Learning device, state inference device, state monitoring system, and learning method

Abstract

The learning device (300) includes a global model construction unit (304) that constructs a first regression model (global model) that fits the learning data explainable by a plurality of explanatory variables and a first explanatory variable (x1) that is an externally specified explanatory variable and is one of the plurality of explanatory variables, a variable selection unit (360) that selects a second explanatory variable (x2) from the plurality of explanatory variables, the variable selection unit selecting a second explanatory variable that is separable from the learning data for target data that is deemed to be varied based on the first regression model constructed by the global model construction unit, and a local model construction unit (354) that constructs a second regression model (local model) that fits the learning data and the first explanatory variable, using the learning data after the target data has been separated, based on the second explanatory variable selected by the variable selection unit and the first explanatory variable.

Description

[Technical field]

[0001] The present disclosure relates to a learning device, a state inference device, a state monitoring system, and a learning method. [Background technology]

[0002] In the manufacturing industry, abnormality detection is performed on equipment such as plants and rotating machines (hereinafter also referred to as "target equipment") using a trained model trained by machine learning. Here, an abnormality in the target equipment is, for example, deterioration of the target equipment. In general, it is more difficult to collect abnormal data from the target equipment than to collect normal data. Therefore, when learning a trained model, a learning device often uses only normal data collected from the target equipment as training data to perform unsupervised learning and learns the model. In this case, an inference device that infers the state of the target equipment uses the trained model to calculate an anomaly degree that indicates how far the state of the target equipment deviates from the normal state. At this time, a threshold value for determining an abnormality degree is set in the inference device to determine that the target equipment is abnormal, and if the calculated anomaly degree exceeds the threshold value, the target equipment is determined to be abnormal. In relation to such an anomaly detection technology, for example, Non-Patent Document 1 and Non-Patent Document 2 describe an anomaly detection technology using a linear regression model and a Gaussian process regression model. [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] Tsuyoshi Ide, "Introduction to Anomaly Detection Using Machine Learning", Corona Publishing, 2019 [Non-Patent Document 2] Tsuyoshi Ide, "Anomaly Detection and Change Detection", Corona Publishing, 2018 Summary of the Invention [Problem to be solved by the invention]

[0004] The above non-patent documents 1 and 2 describe anomaly detection technology when there is no variation in the normal data learned by a learning device. On the other hand, target equipment such as plants and rotating machines rarely continue to operate under constant operating conditions (for example, constant driving and operation patterns), and often operate under various operating conditions. In this case, the normal data collected from the target equipment may vary depending on the operating conditions. The operating conditions of the target equipment are determined by a large number of control information (parameters), ranging from tens to hundreds, such as the current value or voltage value of the power required to operate the target equipment.

[0005] In this way, when the anomaly detection technology described in Non-Patent Document 1 and Non-Patent Document 2 is applied to the case where the normal data varies, it is possible to learn a desired regression model by a learning device (computer) to which the anomaly detection technology is applied. In this case, the learning device (hereinafter also referred to as the "conventional device") clusters normal data so as to cover all patterns, and the inference device performs anomaly detection using the regression model learned as a result. Here, from a physical point of view, the operating conditions of the target equipment suitable for anomaly detection are often limited. For example, in anomaly detection of a rotating machine, the normal data collected from the rotating machine when it is energized may include the influence of electromagnetic noise due to the current. Therefore, in this case, it is desirable for the conventional device to perform analysis (construction and evaluation of a regression model) limited to the normal data collected from the rotating machine when it is not energized. However, in the current state of the art, it is difficult to perform such an analysis, and as a result, there is a problem that the labor required for learning the regression model increases.

[0006] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a learning device that can reduce the amount of labor required for learning, compared to conventional methods, when learning a regression model for detecting anomalies in a target device using variable learning data. [Means for solving the problem]

[0007] The learning device according to the present disclosure includes a global model construction unit that constructs a first regression model that fits the learning data and the first explanatory variable based on learning data that can be explained by a plurality of explanatory variables and a first explanatory variable that is an externally specified explanatory variable and is one of the plurality of explanatory variables; a variable selection unit that selects a second explanatory variable from the plurality of explanatory variables, the variable selection unit selecting a second explanatory variable that is separable from the learning data for target data that is deemed to be variable based on the first regression model constructed by the global model construction unit; and a local model construction unit that constructs a second regression model that fits the learning data and the first explanatory variable using the learning data after the target data has been separated based on the second explanatory variable selected by the variable selection unit and the first explanatory variable. Effect of the Invention

[0008] According to the present disclosure, when learning a model for detecting anomalies in a target device using variable data collected from the target device, it is possible to reduce the amount of work required for learning compared to conventional methods. [Brief description of the drawings]

[0009] [Figure 1] 1 is a diagram illustrating a configuration example of a state monitoring system according to a first embodiment. [Diagram 2] FIG. 2 is a diagram illustrating an example of the configuration of a learning device according to the first embodiment. [Diagram 3] 5A to 5C are diagrams showing an example of vibration data and control information data in the first embodiment. [Figure 4] FIG. 2 is a diagram illustrating an example of the configuration of a global learning unit (a global model construction unit and a model evaluation unit) in the first embodiment. [Diagram 5] FIG. 2 is a diagram showing an example of an image of a global model in the first embodiment. [Figure 6] FIG. 2 is a diagram showing an example of an image of a global model in the first embodiment. [Figure 7] FIG. 4 is a diagram for explaining a specific example of classification processing by a filter processing unit in the first embodiment. [Figure 8] 2 is a diagram illustrating an example of the configuration of a local learning unit (a range selection unit, a local model construction unit, and a model evaluation unit) in the first embodiment. FIG. [Figure 9] 4A to 4C are diagrams for explaining a specific example of processing by a distribution calculation unit in the first embodiment. [Figure 10] FIG. 2 is a diagram showing an example of a probability distribution map generated by a second variable selection processing unit in the first embodiment. [Figure 11] 4 is a diagram showing an example of a distribution map of vibration data generated by a region evaluation unit in the first embodiment. FIG. [Figure 12] FIG. 4 is a diagram showing an example of an image indicating a calculation result of a prediction error, generated by an image output unit in the first embodiment. [Figure 13] 4 is a flowchart illustrating an example of the operation of the learning device according to the first embodiment. [Figure 14] 14A and 14B are diagrams illustrating an example of a hardware configuration of the learning device according to the first embodiment. [Figure 15] 1 is a diagram illustrating an example of a configuration of a state inference device according to a first embodiment. [Figure 16] 2 is a diagram illustrating an example of the configuration of an evaluation unit in the state inference device according to the first embodiment. [Figure 17] FIG. 4 is a diagram showing an example of an image showing a comparison result generated by an image output unit in the first embodiment. [Figure 18] 4 is a flowchart illustrating an example of the operation of the state inference device according to the first embodiment. [Figure 19] 19A and 19B are diagrams illustrating an example of a hardware configuration of the state inference device according to the first embodiment. [Figure 20] FIG. 20A is a diagram for explaining the difficulty of selecting an appropriate regression model in a conventional device, and FIG. 20B is a diagram for explaining the difficulty of evaluating the variability of training data (normal data) in a conventional device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. Embodiment 1

[0011] Fig. 1 is a diagram showing an example of the configuration of a state monitoring system 1000 according to embodiment 1. The state monitoring system 1000 includes, for example, a recording unit 100, a learning data recording unit 200, a learning device 300, and a state inference device 600, as shown in Fig. 1.

[0012] The recording unit 100 is configured with a recording medium such as a hard disk drive (HDD) and a solid state drive (SDD). The recording unit 100 records data indicating a trained model constructed by the learning device 300.

[0013] The learning data recording unit 200 is configured with a recording medium such as a hard disk drive (HDD) and a solid state drive (SDD), etc. The learning data recording unit 200 records learning data used by the learning device 300 to construct a trained model.

[0014] The learning device 300 and the state inference device 600 are each configured to be connectable to the recording unit 100. Furthermore, the learning device 300 is configured to be connectable to a learning data recording unit 200.

[0015] The learning device 300 constructs a trained model for detecting anomalies in equipment (target equipment) such as a plant and a rotating machine by machine learning, using the training data recorded in the training data recording unit 200. The learning device 300 causes the recording unit 100 to record data indicating the constructed trained model.

[0016] The state inference device 600 uses the learned model indicated by the data recorded in the recording unit 100 by the learning device 300 to infer the state of the target device, thereby detecting an abnormality (e.g., deterioration) of the target device.

[0017] The condition monitoring system 1000 includes a first external evaluation device 400, a second external evaluation device 500, and a third external evaluation device 700, as shown in FIG.

[0018] The first external evaluation device 400 and the second external evaluation device 500 are configured to be connectable to the learning device 300. The first external evaluation device 400 and the second external evaluation device 500 are devices that serve as interfaces for the learning device 300, such as transmitting instructions from a user to the learning device 300 and presenting the contents of processing by the learning device 300 to the user.

[0019] The third external evaluation device 700 is configured to be connectable to the state inference device 600. The third external evaluation device 700 is a device that serves as an interface for the state inference device 600, such as transmitting instructions from a user to the state inference device 600 and presenting the contents of processing by the state inference device 600 to the user.

[0020] In the following description, for convenience of explanation, the learning device 300 will be described in detail first, and then the state inference device 600 will be described in detail.

[0021] <Learning device 300> 2 is a diagram showing an example of the configuration of learning device 300 according to embodiment 1. Learning device 300 includes a global learning unit 301, a local learning unit 350, and an intermediate recording unit 390, for example, as shown in FIG.

[0022] The learning device 300 uses a target variable explained by any number of explanatory variables (hereinafter also referred to as a "group of explanatory variables") as learning data, and performs two-stage machine learning, namely learning by a global learning unit 301 and learning by a local learning unit 350, to construct a trained model for detecting abnormalities in a target device.

[0023] Specifically, first, the global learning unit 301 acquires a first explanatory variable selected from a group of explanatory variables by a user having skills and knowledge regarding the target device. The global learning unit 301 also performs machine learning using a target variable explained by the acquired first explanatory variable as learning data, and constructs a trained model that fits between the learning data and the first explanatory variable. The global learning unit 301 also obtains an evaluation of the trained model from the user via the first external evaluation device 400. As a result, the global learning unit 301 constructs a global trained model that has acquired validity from a physical point of view. The global learning unit 301 causes the intermediate recording unit 390 to record data indicating the constructed trained model.

[0024] Next, the local learning unit 350 classifies the above-mentioned learning data into "data considered to be scattered (large variation)" and "data considered to be not scattered (small variation)" using the learned model indicated by the data recorded in the intermediate recording unit 390 by the global learning unit 301. In addition, the local learning unit 350 searches the above-mentioned explanatory variable group for a second explanatory variable that is an explanatory variable capable of accurately separating "data considered to be scattered (large variation)" from the above-mentioned learning data and is different from the first explanatory variable selected by the user. Note that "separable" or "separable" here does not mean that "data considered to be scattered (large variation)" can be completely separated from the learning data, but means that the latter can be roughly separated from the former.

[0025] Then, the local learning unit 350 performs machine learning using the learning data after the "data considered to be scattered (large variation)" is separated based on the searched second explanatory variable and the above-mentioned first explanatory variable, thereby constructing a local trained model that fits between the separated learning data and the first explanatory variable. Here, the local trained model means a model trained using the learning data after the "data considered to be scattered (large variation)" is separated from the physical viewpoint.

[0026] Here, the learning data used by the learning device 300 for learning is recorded in the learning data recording unit 200. The learning data recording unit 200 includes a vibration DB 210 and a control information DB 220, for example, as shown in FIG.

[0027] The vibration DB 210 records vibration data. The vibration data is data indicating a time change in a vibration amplitude value, for example, as shown in the top graph of FIG. 3. The vibration data may be data indicating a time change in a feature of the vibration amplitude value. In this case, the feature of the vibration amplitude value may be, for example, an RMS value of the vibration amplitude value. In the following description, a case where the vibration data is the RMS value of the vibration amplitude value will be described as an example.

[0028] The control information DB 220 records control information data, which is an explanatory variable. The control information data is data indicating the time change of the control information, for example, as shown in the second to fourth graphs from the top in Fig. 3. Here, the control information is a parameter that determines the operating conditions of the target device, such as the rotation speed when the target device is a rotating machine, the current value of the driving power of the rotating machine, and Accel / Decel.

[0029] Each control information data recorded in the control information DB 220 is synchronized in time with the vibration data recorded in the vibration DB 210. In this case, the vibration data corresponds to the objective variable, and each control information data corresponds to the explanatory variable that explains the vibration data.

[0030] In the following description, the vibration data corresponds to the objective variable and each control information data corresponds to the explanatory variable, but this is merely an example, and the objective variable and the explanatory variable may be data other than those described above. In the following description, the explanatory variable group is also referred to as the control information group.

[0031] <Global Learning Unit 301> The global learning unit 301 includes a data extraction unit 302, an explanatory variable acquisition unit 303, a global model construction unit 304, and a model evaluation unit 305, as shown in FIG.

[0032] (Explanatory variable acquisition unit 303) First, the user selects any control information from a group of explanatory variables (group of control information) that explain the vibration data, and inputs the selected control information to the first external evaluation device 400. Here, for ease of explanation, it is assumed that the user selects "rotation speed" as the control information. The explanatory variable acquisition unit 303 acquires the control information input by the user to the first external evaluation device 400 from the first external evaluation device 400 as a first explanatory variable x1. In addition, the explanatory variable acquisition unit 303 outputs data indicating the acquired first explanatory variable x1 to the data extraction unit 302 as a variable descriptor D13.

[0033] (Data extraction unit 302) The data extraction unit 302 acquires the variable descriptor D13 from the explanatory variable acquisition unit 303. The data extraction unit 302 acquires control information data corresponding to the acquired variable descriptor D13 from the control information DB 220 in the learning data recording unit 200. In this example, since the variable descriptor D13 indicates "rotation speed", the data extraction unit 302 acquires the second control information data from the top in Fig. 3 from the control information DB 220.

[0034] Furthermore, the data extraction unit 302 acquires vibration data from the vibration DB 210 in the learning data recording unit 200. Then, the data extraction unit 302 outputs the acquired control information data and vibration data to the global model construction unit 304 as learning data D12.

[0035] (Global model construction unit 304) The global model construction unit 304 learns a regression model that fits the vibration data and the first explanatory variable x1, based on the vibration data that can be explained by a plurality of explanatory variables and the first explanatory variable x1, which is an externally specified explanatory variable and is one of the plurality of explanatory variables. The global model construction unit 304 includes a model construction unit 311 and a model update unit 312, for example, as shown in FIG.

[0036] The model construction unit 311 acquires the learning data D12 from the data extraction unit 302. The model construction unit 311 uses the acquired learning data D12 to perform unsupervised learning to construct a regression model. At this time, the model construction unit 311 performs unsupervised learning using the control information data (rotation speed) included in the learning data D12 as an explanatory variable and the vibration data (RMS value of vibration amplitude value) included in the learning data D12 as a target variable. Note that as the learning method in this case, a known learning method such as linear regression, polynomial regression, and Gaussian process regression may be used. In the following description, the regression model constructed here is also referred to as a "global model."

[0037] The global model is a model that receives the first explanatory variable x1 (control information data) as input and outputs a response variable (vibration data), but it is sufficient for the global model to reproduce a rough regression tendency between the control information data and the vibration data. Therefore, when constructing the global model, the model construction unit 311 does not necessarily need to use all the control information data and vibration data included in the learning data D12. For example, the model construction unit 311 may construct the global model using the control information data and vibration data corresponding to an arbitrary time range designated by the user.

[0038] The model construction unit 311 outputs data indicating the constructed global model (hereinafter also referred to as "global model data"), and the control information data and vibration data used in learning the global model, to the model update unit 312 as data D18.

[0039] The model construction unit 311 may construct global models of multiple patterns. In this case, the model construction unit 311 outputs the global model data for each pattern, and the control information data and vibration data used in the learning, as data D18, to the model update unit 312.

[0040] The model update unit 312 acquires data D18 from the model construction unit 311. When the model evaluation unit 355 of the local learning unit 350 (described later) outputs data D60, the model update unit 312 acquires the data D60 from the model evaluation unit 355 and updates (reconstructs) the global model in response to a user instruction. The update process in this case will be described later.

[0041] When the model updating unit 312 updates the global model, it outputs data indicating the updated global model and data combining the control information data and vibration data used in the update as data D14 to the model evaluation unit 305. When the model evaluation unit 355 does not output data D60 and the global model is not updated, the model updating unit 312 outputs data D18 as it is to the model evaluation unit 305 as data D14.

[0042] (Model evaluation unit 305) The model evaluation unit 305 receives an external (e.g., a user) evaluation of the global model indicated by the data included in the data D14. The model evaluation unit 305 includes an image output unit 313 and a model determination unit 314, as shown in FIG.

[0043] The image output unit 313 acquires data D14 from the model update unit 312. Based on the global model data included in the acquired data D14, the image output unit 313 visualizes the global model indicated by the data, and generates data indicating an image of the global model (hereinafter, also referred to as "global model image data"). The image output unit 313 outputs the generated global model image data to the first external evaluation device 400 as data D15.

[0044] An example of an image of a global model is shown in Fig. 5. For example, in Fig. 5, reference numeral 501 denotes a curve (prediction line) showing a regression equation obtained by a global model, and reference numeral 502 denotes a boundary of a confidence interval (e.g., curve 501 ± 5%) set for the curve (prediction line) showing the regression equation.

[0045] In addition, when the data D14 includes multiple patterns of global model data, the image output unit 313 generates global model image data for each pattern based on each global model data, for example as shown in Figure 6, and outputs each generated global model image data to the first external evaluation device 400 as data D15.

[0046] The first external evaluation device 400 acquires data D15 from the image output unit 313. The first external evaluation device 400 displays one or more images of the global model on a display unit (not shown) such as a display based on the acquired data D15. When there is only one image of the global model displayed on the display unit, the user checks the image, judges whether or not the global model is considered to be correct from a physical point of view, and if it is considered to be correct, inputs a judgment result indicating that to the first external evaluation device 400. When there are multiple images of the global model displayed on the display unit, the user checks each image, selects a global model considered to be correct from a physical point of view, and inputs the selection result to the first external evaluation device 400.

[0047] At this time, the user specifies, within the time range on the time series of the control information data (here, the rotation speed) used in the learning, a range in which the variation in the vibration data is considered to be relatively small, or a range in which the characteristics of the target device are considered to be reflected in the vibration data, as a search range S, and inputs the range S to the first external evaluation device 400. Here, the search range S is a variable used when searching for a region with small variation in the vibration data in the range selection unit 352 of the local learning unit 350 described later.

[0048] The first external evaluation device 400 outputs to the model determination unit 314, as data D16, data that is a combination of data indicating the above judgment result or the above selection result by the user and data indicating the search width S input by the user.

[0049] If there is no global model that is considered to be correct from a physical point of view, the user may perform, for example, one of the following two operations. For example, the user may use the first external evaluation device 400 to discard the global model constructed at that time, and input control information different from the initially input control variable (here, the rotation speed) to the first external evaluation device 400. Then, the user may cause the explanatory variable acquisition unit 303 to acquire the different control information as a new first explanatory variable x1, and thereafter, the user may cause the global model construction unit 304 to reconstruct the global model through the same processes as those described above.

[0050] Alternatively, the user may leave the first explanatory variable x1 as it is, use the first external evaluation device 400 to exclude data that is considered to be scattered from the vibration data based on the image of the global model, and then have the global model construction unit 304 reconstruct the global model. The user may repeat any of the above operations until a global model that is considered to be correct from a physical point of view is constructed.

[0051] The model determination unit 314 acquires data D16 from the first external evaluation device 400. Based on the acquired data D16, the model determination unit 314 records data indicating a global model that the user has determined to be correct from a physical perspective, or data indicating a global model that the user has selected as a correct model from a physical perspective, as data D17 in the intermediate recording unit 390. The model indicated by this data D17 corresponds to the global trained model described above.

[0052] At this time, the model determination unit 314 treats the data indicating the search width S contained in the data D16 as a range descriptor, and includes the range descriptor and an identifier (e.g., name) of the control information data used to train the global model in the data D17 and records them in the intermediate recording unit 390.

[0053] (Intermediate recording unit 390) The intermediate recording unit 390 records the data D17. That is, the intermediate recording unit 390 records data indicating a global model equivalent to a global trained model (global model data), an identifier of the control information data, and a range descriptor.

[0054] <Local Learning Unit 350> 2, the local learning unit 350 includes a second variable selection unit 360, a local model construction unit 354, and a model evaluation unit 355. The second variable selection unit 360 includes a filter processing unit 351, a range selection unit 352, and a second variable selection processing unit 353, for example.

[0055] (Filter processing unit 351) The filter processing unit 351 acquires the data D17 (global model data, an identifier of the control information data, and a range descriptor) recorded in the intermediate recording unit 390 as a global model descriptor D51.

[0056] In addition, the filter processing unit 351 refers to the learning data recording unit 200 and acquires, as data D52, the vibration data recorded in the vibration DB 210 and data corresponding to the identifier of the control information data included in the data D17 among the control information data recorded in the control information DB 220.

[0057] Then, based on the acquired global model descriptor D51 and data D52, the filter processing unit 351 classifies (filters) the vibration data included in the data D52 into data considered to be scattered and data considered not to be scattered, and labels both of the classified data.

[0058] For example, the filter processing unit 351 determines the degree of variation in the vibration data based on the global model, labels the vibration data that is considered to be varied as “Data A”, and labels the vibration data that is considered not to be varied as “Data B”. Then, the filter processing unit 351 outputs the vibration data to which the label has been added and the data combined with the above-mentioned global model descriptor D51 to the range selection unit 352 as data D53.

[0059] A specific example of the classification process by the filter processing unit 351 is shown in Fig. 7. For example, Fig. 7A shows a distribution diagram of vibration data (RMS value) when the horizontal axis represents the first explanatory variable x1 (rotation speed) and the vertical axis represents vibration data. Fig. 7B shows an image of the global model indicated by the global model data included in the data D17 recorded in the intermediate recording unit 390. Fig. 7C is a distribution diagram of the vibration data after classification process by the filter processing unit 351.

[0060] For example, the filter processing unit 351 superimposes Fig. 7A and Fig. 7B, and among the vibration data shown in Fig. 7A, the vibration data located outside the confidence interval set for the curve (prediction line) 701 in the global model in Fig. 7B is regarded as data that is scattered, and labels the data as "Data A" (lower diagram in Fig. 7C). Also, among the vibration data shown in Fig. 7A, the filter processing unit 351 regards the vibration data located inside the confidence interval as data that is not scattered, and labels the data as "Data B" (upper diagram in Fig. 7C).

[0061] In the following description, for ease of understanding, data that is deemed to be scattered by the filter processing unit 351 will be simply referred to as "Data A," and data that is deemed not to be scattered will be simply referred to as "Data B." These data will also be collectively referred to as "labeled data."

[0062] (Range selection unit 352) The range selection unit 352 includes a distribution calculation unit 361 and a distribution difference comparison unit 362, as shown in FIG.

[0063] The distribution calculation unit 361 acquires data D53 from the filter processing unit 351. The distribution calculation unit 361 analyzes the distribution of DataA and DataB based on the labeled data included in the acquired data D53. Specifically, the distribution calculation unit 361 calculates a probability distribution pA of DataA and a probability distribution pB of DataB for a first explanatory variable x1, as shown in FIG. 9, for example, and outputs data indicating the calculated probability distributions and data D53 to the distribution difference comparison unit 362.

[0064] 9 indicates the above-mentioned search width input by the user via the first external evaluation device 400. In the example of FIG. 9, the search width is set to a range of 500 to 1000 rotations. This means that the user has determined that the variation in vibration data is relatively small if the rotation speed is between 500 and 1000.

[0065] The distribution difference comparison unit 362 acquires data indicating the probability distributions pA and pB from the distribution calculation unit 361, and data D53. The distribution difference comparison unit 362 obtains the difference between the probability distributions pA and pB based on the acquired data indicating the probability distributions pA and pB. At this time, the distribution difference comparison unit 362 selects, from the search width indicated by the range descriptor included in the data D53, a range on the time series of the control information data (rotation speed) where the difference is the largest and where the probability distribution pB is larger than the probability distribution pA.

[0066] Specifically, the distribution difference comparison unit 362 calculates the difference pB-pA based on the probability distributions pA and pB acquired from the distribution calculation unit 361. At this time, assuming that the search width is S, the distribution difference comparison unit 362 selects a range Ω in which pB|Ω-pA|Ω (where Ω=[a, a+S], where a is an arbitrary value of the first explanatory variable x1) is maximum from the search width S, and sets the selected range Ω as a new range descriptor. Then, the distribution difference comparison unit 362 outputs data combining the new range descriptor, the labeled data (DataA and DataB), and the global model descriptor D51 to the second variable selection processing unit 353 as data D54.

[0067] Note that, here, an example has been described in which the distribution difference comparing unit 362 selects the range Ω in which pB|Ω-pA|Ω is maximum, but the distribution difference comparing unit 362 is not limited to this. For example, the distribution difference comparing unit 362 may select the range Ω in which pB|Ω-pA|Ω is equal to or greater than a predetermined value, and set the selected range Ω as a new range descriptor.

[0068] (Second variable selection processing unit 353) The second variable selection unit 353 acquires data D54 from the range selection unit 352. Then, the second variable selection unit 353 selects, from the explanatory variable group, an explanatory variable (control information) other than the first explanatory variable x1 selected by the user during learning in the global learning unit 301, which is capable of separating DataA and DataB with high accuracy. In the following description, the explanatory variable selected here is also referred to as the "second explanatory variable x2."

[0069] For example, the second variable selection processing unit 353 generates a probability distribution diagram as shown in Fig. 10. In Fig. 10, the horizontal axis indicates an explanatory variable other than the first explanatory variable x1 that is a candidate for the second explanatory variable x2. Also, the vertical axis indicates the occurrence frequency of DataA and DataB that exist in the above-mentioned range Ω included in the data D54.

[0070] At this time, the second variable selection processing unit 353 searches for explanatory variables in the following procedure while sequentially changing the explanatory variables that are candidates for the second explanatory variable x2, and selects the searched explanatory variable as the second explanatory variable x2.

[0071] (1) In a probability distribution diagram such as that shown in Fig. 10, for example, when the length of the entire horizontal axis is "100", the second variable selection processing unit 353 sets the range of the horizontal axis in which the proportion of Data A among all Data A is "100-ε"% or more (ε is a small positive integer) as Y (first range). For example, the second variable selection processing unit 353 sets ε=5, and sets Y to the range of the horizontal axis in which 95% or more of all Data A is included.

[0072] (2) Next, the second variable selection processing unit 353 sets the range excluding the range Y on the horizontal axis of the probability distribution diagram as the range X (second range), and searches for explanatory variables such that the proportion of Data B among all data included in the range X is a predetermined value (e.g., 80%) or more. Then, the second variable selection processing unit 353 selects the explanatory variable that has been searched for as the second explanatory variable x2. Note that, when the second variable selection processing unit 353 searches for multiple explanatory variables such that the proportion of Data B among all data included in the range X is a predetermined value or more, it selects, for example, the explanatory variable that makes the proportion of Data B in the range X the largest as the second explanatory variable x2.

[0073] If the search fails, the second variable selection processing unit 353 repeats the above steps (1) and (2) while sequentially changing the explanatory variables that are candidates for the second explanatory variable x2. Then, the second variable selection processing unit 353 outputs data combining the second explanatory variable x2 selected by the above procedure with the above data D54 to the local model construction unit 354 as data D56.

[0074] This second explanatory variable x2 is a variable different from the first explanatory variable x1 specified by the user during learning in the global learning unit 301, and is a variable that is likely to be able to accurately (precisely) separate DataA and DataB when combined with the first explanatory variable x1.

[0075] (Local model construction unit 354) The local model construction unit 354 includes a region evaluation unit 363 and a model construction unit 364, as shown in FIG.

[0076] (Area Evaluation Unit 363) The region evaluation unit 363 acquires data D56 from the second variable selection processing unit 353. The region evaluation unit 363 generates a distribution diagram of vibration data, for example, as shown in FIG 11, by using the second explanatory variable x2 and the first explanatory variable x1 (here, the rotation speed) included in the acquired data D56.

[0077] This distribution chart, for example as shown in Fig. 11, is a chart in which the horizontal axis is a first explanatory variable x1 (rotation speed) and the vertical axis is a second explanatory variable x2, and vibration data is displayed in a region (hereinafter also referred to as a "combination region") determined by a combination of both variables, and shows the regions in which Data A and Data B appear in the combination region. Note that in Fig. 11, Data A is shown by gray dots and Data B is shown by black dots.

[0078] In this way, by displaying Data A and Data B in the combination area, the area evaluation unit 363 can clearly indicate areas in the combination area where Data A is relatively abundant and areas where Data A is relatively scarce (indicated by symbols U1 to U3 in FIG. 11). The area evaluation unit 363 outputs data showing the generated distribution map to the second external evaluation device 500 as data D62.

[0079] The second external evaluation device 500 acquires data D62 from the region evaluation unit 363. The second external evaluation device 500 displays an image of the distribution map on a display unit (not shown) such as a display based on the acquired data D62.

[0080] The user refers to the image of the distribution map displayed on the display unit, selects an area with relatively few Data A among the above combination areas, such as areas U1 to U3 in Fig. 11, and inputs the selected area to the second external evaluation device 500. At this time, the user may select only one area, such as area U1, or may select multiple areas, such as areas U1 to U3. The second external evaluation device 500 outputs data indicating the input area to the model construction unit 364 as area range data D63.

[0081] The model construction unit 364 acquires the area range data D63 from the second external evaluation device 500. The model construction unit 364 also acquires the data D56 from the second variable selection processing unit 353. Then, based on the acquired area range data D63 and data D56, the model construction unit 364 identifies vibration data included in the areas U1 to U3 in FIG. 11, for example, and performs unsupervised learning using the identified vibration data and the control information data corresponding to the vibration data as learning data to construct a regression model. In the following description, the regression model constructed here is also referred to as a "local model." The local model is a model that receives a first explanatory variable x1 (control information data) as an input and outputs a response variable (vibration data).

[0082] When a plurality of regions are selected by the user, the model construction unit 364 constructs a local model for each of the selected regions. At this time, the model construction unit 364 uses a learning model similar to the learning model used by the global model construction unit 304 of the global learning unit 301. However, both learning models do not necessarily have to be the same model.

[0083] The model construction unit 364 outputs data indicating the constructed local model (hereinafter also referred to as “local model data”) and the vibration data (Data A and Data B) used for learning to the model evaluation unit 355 as data D57.

[0084] (Model Evaluation Unit 355) The model evaluation unit 355 receives an external (e.g., a user) evaluation of the local model indicated by the local model data included in the data D57. The model evaluation unit 355 includes a prediction error calculation unit 365, an image output unit 366, and a model determination unit 367, as shown in FIG.

[0085] The prediction error calculation unit 365 acquires the data D57 from the model construction unit 364. The prediction error calculation unit 365 calculates the prediction error of the local model based on the acquired data D57.

[0086] For example, the prediction error calculation unit 365 inputs the first explanatory variable x1 (rotation speed) to the local model indicated by the local model data included in the data D57, and calculates how much error there is in the vibration data (RMS value) output from the local model at this time compared to the vibration data that should be output. At this time, the prediction error calculation unit 365 calculates the prediction error using a value such as the mean absolute percentage error (MAPE). The prediction error calculation unit 365 outputs the first explanatory variable x1 and vibration data used in calculating the prediction error, and data indicating the calculated prediction error, to the image output unit 366.

[0087] The image output unit 366 acquires the first explanatory variable x1, the vibration data, and data indicating the prediction error from the prediction error calculation unit 365. Then, based on the acquired data, the image output unit 366 generates data indicating an image showing a predicted result for each region, for example, as shown on the right side of FIG. 12. Then, the image output unit 366 outputs data combining the generated image and the prediction error to the second external evaluation device 500 as data D58. Note that, in the image shown on the right side of FIG. 12, a curve (prediction line) indicating a regression equation obtained by a local model and a boundary of a confidence interval (for example, the curve ±5%) set for the curve (prediction line) indicating the regression equation are shown, similarly to the image of the global model shown in FIG. 5.

[0088] The second external evaluation device 500 acquires data D58 from the image output unit 366. The second external evaluation device 500 displays, for example, an image shown on the right side of FIG. 12 on a display unit (not shown) such as a display based on the acquired data D58. The user refers to the image displayed on the display unit, determines a local model to be finally output to the recording unit 100 from among the local models, and inputs an identifier of the determined local model to the second external evaluation device 500. The second external evaluation device 500 outputs the input identifier of the local model to the model determination unit 367 as data D59.

[0089] The model determination unit 367 acquires data D59 from the second external evaluation device 500. The model determination unit 367 causes the recording unit 100 to record, as data D61, data indicating the local model that the user has finally determined to be output based on the acquired data D59.

[0090] At this time, the model determination unit 367 causes data (hereinafter also referred to as "control condition data") indicating the conditions (hereinafter also referred to as "control conditions") of the control information (explanatory variables) when the local model that the user decided to output was constructed to be included in the data D61 and recorded in the recording unit 100. Here, the control conditions refer to, for example, the type of the first explanatory variable x1 (such as the rotation speed), the type of the second explanatory variable x2 (other than the rotation speed), the range of the first explanatory variable x1 and the range of the second explanatory variable x2 in which the learning data existed when the local model was constructed, and the like.

[0091] When a user sets a plurality of local models as output targets, the model determination unit 367 records the plurality of local model data in the recording unit 100. In this case, the model determination unit 367 also records the control condition data in the recording unit 100 in association with each of the plurality of local models.

[0092] When the user refers to the image displayed on the display unit but ultimately fails to find a local model to be output to the recording unit 100, the user inputs, for example, a message to that effect to the second external evaluation device 500. The second external evaluation device 500 outputs data indicating that a local model to be output was not found to the model determination unit 367 as data D59.

[0093] When the model determination unit 367 acquires the data D59, it acquires data D57 (data combining the local model data and the vibration data (Data A and Data B) used for learning the local model) from the prediction error calculation unit 365, and outputs the acquired data D57 as data D60 to the model update unit 312 of the global learning unit 301.

[0094] The model update unit 312 acquires data D60 from the model determination unit 367. Upon acquiring the data D60, the model update unit 312 causes the display unit of the first external evaluation device 400 to display the contents of the data D60. The model update unit 312 also causes the display unit of the first external evaluation device 400 to instruct the user to perform an update process (i.e., rebuild) of the global model.

[0095] In response to this display, the user reselects an explanatory variable other than the first explanatory variable x1 that was initially selected when constructing the global model, and inputs the newly selected explanatory variable to the first external evaluation device 400. Thereafter, the model update unit 312 updates (reconstructs) the global model in the same manner as the model construction unit 311 described above.

[0096] Here, an example has been described in which the user reselects an explanatory variable other than the first explanatory variable x1 initially selected when constructing the global model to update (reconstruct) the global model, but the method of updating (reconstructing) the global model is not limited to this. For example, the user may change the range of the first explanatory variable x1 from the initial state, such as narrowing the range of the first explanatory variable x1, while leaving the first explanatory variable x1 initially selected when constructing the global model as is. In this case, the model update unit 312 may update (reconstruct) the global model using learning data included in the changed range.

[0097] Furthermore, the model update unit 312 may, for example, not update the global model, but instruct the user to re-input the search width via the first external evaluation device 400. In this case, the user inputs a new search width via the first external evaluation device 400, and the new search width is recorded as a range descriptor in the intermediate recording unit 390. Thereafter, based on this new range descriptor, a new second explanatory variable x2 is selected by the second variable selection processing unit 353, and the local learning unit 350 reconstructs the local model.

[0098] Alternatively, the model update unit 312 may not update the global model, but may instruct the user to reselect the regions U1 to U3 shown in Fig. 11 via the second external evaluation device 500. In this case, the user inputs a new region via the second external evaluation device 500, and data indicating the new region is sent as region range data to the model construction unit 364. Thereafter, the model construction unit 364 reconstructs a local model using this new region range data.

[0099] Next, an example of the operation of the learning device 300 according to the first embodiment will be described with reference to the flowchart shown in FIG.

[0100] First, the explanatory variable acquisition unit 303 acquires the control information input by the user to the first external evaluation device 400 as a first explanatory variable x1 from the first external evaluation device 400 (step ST1). The explanatory variable acquisition unit 303 outputs data indicating the acquired first explanatory variable x1 to the data extraction unit 302 as a variable descriptor D13.

[0101] Next, the data extraction unit 302 acquires control information data corresponding to the acquired variable descriptor D13 from the control information DB 220 in the learning data recording unit 200. In addition, the data extraction unit 302 acquires vibration data, which is learning data, from the vibration DB 210 in the learning data recording unit 200 (step ST2).

[0102] Next, the model construction unit 311 constructs a global model using the data acquired in step ST2 (step ST3).

[0103] Next, the image output unit 313 generates global model image data and outputs the generated global model image data to the first external evaluation device 400 (step ST4). The first external evaluation device 400 displays an image of the global model on a display unit such as a display based on the acquired data, and accepts a judgment result or a selection result by the user. The first external evaluation device 400 outputs data indicating the judgment result or the selection result by the user to the model determination unit 314.

[0104] Next, the model determination unit 314 acquires data indicating the judgment result or selection result by the user, and judges whether or not the result indicates that any global model has been selected (step ST5). As a result, if the result indicates that no global model has been selected (step ST5; No), the process returns to step ST1, and the explanatory variable acquisition unit 303 acquires a new first explanatory variable x1 from the user via the first external evaluation device 400. Thereafter, steps ST2 to ST5 are repeated.

[0105] On the other hand, if the above result indicates that one of the global models has been selected (step ST5; Yes), the process proceeds to step ST6, and the filter processing unit 351 classifies (filters) the vibration data into data considered to be varied (Data A) and data considered not to be varied (Data B) (step ST6).

[0106] Next, the distribution calculation unit 361 calculates the probability distribution pA of DataA and the probability distribution pB of DataB with respect to the first explanatory variable x1. The distribution difference comparison unit 362 selects the range Ω within the search width S where pB|Ω-pA|Ω (Ω=[a, a+S], a is an arbitrary value of the first explanatory variable x1) is maximum (step ST7).

[0107] Next, the second variable selection processing unit 353 selects a second explanatory variable x2 that is an explanatory variable other than the first explanatory variable x1 and that can accurately separate Data A and Data B (step ST8).

[0108] Next, the region evaluation unit 363 generates a distribution map showing vibration data in a region defined by a combination of the first explanatory variable x1 and the second explanatory variable x2. Then, the model construction unit 364 accepts a region selection made by the user based on the distribution map (step ST9).

[0109] Next, the model constructing unit 364 constructs a local model by using the vibration data and control information data included in the region selected in step ST9 (step ST10).

[0110] Next, the prediction error calculation unit 365 calculates the prediction error of the local model, and the image output unit 366 generates image data indicating the prediction result and outputs it to the second external evaluation device 500. The second external evaluation device 500 displays the image indicating the prediction result on the display unit and accepts the judgment result or selection result by the user. The second external evaluation device 500 outputs data indicating the judgment result or selection result by the user to the model determination unit 367.

[0111] Next, the model determination unit 367 acquires data indicating the judgment result or selection result by the user, and judges whether or not the result indicates that any local model has been selected (step ST11). As a result, if the result indicates that no local model has been selected (step ST11; No), the model update unit 312 instructs the user to select a new first explanatory variable x1 via the first external evaluation device 400. Thereafter, the process proceeds to step S21, and the explanatory variable acquisition unit 303 acquires a new first explanatory variable x1 from the user via the first external evaluation device 400. Thereafter, steps ST2 to ST11 are repeated.

[0112] 13, if the result indicates that no local model is selected (step ST11; No), the model update unit 312 may instruct the user to change the range of the first explanatory variable x1, such as narrowing the range of the first explanatory variable x1, via the first external evaluation device 400. If the model update unit 312 instructs the user to change the range of the first explanatory variable x1, the process may return to step ST2.

[0113] Similarly, when the above result indicates that no local model has been selected (step ST11; No), the model update unit 312 may instruct the user to re-input the search width or re-select the regions U1 to U3 via the first external evaluation device 400. When the model update unit 312 instructs the user to re-input the search width, the process returns to step ST7, and when the model update unit 312 instructs the user to re-select the regions U1 to U3, the process returns to step ST9.

[0114] On the other hand, if the result indicates that any local model has been selected (step ST11; Yes), the process proceeds to step S32, and the model determination unit 367 causes the recording unit 100 to record data indicating the selected local model (step ST12). The model determination unit 367 also causes the recording unit 100 to record the control condition data.

[0115] As configured as described above, the learning device 300 of embodiment 1 can reduce the amount of work required for learning a model for detecting anomalies in a target device using variable data collected from the target device, compared to the conventional method.

[0116] To add to this point, for example, in the conventional device, normal data (learning data) with variation is clustered so as to cover all patterns, but from a physical point of view, the operating conditions of the target equipment suitable for anomaly detection are often limited. However, in the conventional device, it is difficult to perform learning using normal data collected under the limited operating conditions, and as a result, there is a problem that the labor required for learning the regression model increases. In addition, in the conventional device, when there are many control information (parameters) that determine the operating conditions, or when each control information has a continuous value, there is a problem that countless methods of condition classification are possible, and calculation costs are high. Furthermore, in the conventional device, even if several regression models can be constructed by clustering normal data so as to cover all patterns, for example, as shown in FIG. 20A, it is difficult to select an appropriate regression model from among them. In addition, in the conventional device, it is expected that the evaluation of the variation of normal data will differ depending on which regression model is selected. Therefore, in the conventional device, it is difficult to evaluate whether the normal data present in a square frame can truly be said to be data with variation, for example, as shown in FIG. 20B.

[0117] In this regard, the learning device 300 according to the first embodiment, as described above, first constructs a global trained model (global model) that has acquired validity from a physical point of view by the global model construction unit 304, then selects a second explanatory variable x2 that can separate target data considered to be scattered from the training data by the second variable selection unit 360, and constructs a regression model (local model) that fits between the training data and the first explanatory variable x1 by the local model construction unit 354 using the training data after the target data has been separated based on the second explanatory variable x2 and the first explanatory variable x1. In this way, the learning device 300 increases the possibility of finding limited operating conditions for the target equipment by selecting the second explanatory variable x2 that can be separated from the training data for target data considered to be scattered, and can reduce the labor and calculation costs required for learning compared to conventional devices. Furthermore, the learning device 300 is capable of separating target data that is considered to be variable from the training data, which not only makes it easy to select an appropriate regression model and evaluate the variation in the training data, which were difficult to do with conventional devices, but also makes it possible to construct a regression model with high inference accuracy.

[0118] Next, an example of a hardware configuration of the learning device 300 according to the first embodiment will be described with reference to Fig. 14. Each function of the global learning unit 301 and the local learning unit 350 in the learning device 300 is realized by a processing circuit. The processing circuit may be dedicated hardware as shown in Fig. 14A, or may be a CPU (also referred to as a Central Processing Unit, a processing unit, an arithmetic unit, a microprocessor, a microcomputer, a processor, or a DSP (Digital Signal Processor)) 72 that executes a program stored in a memory 73 as shown in Fig. 14B.

[0119] When the processing circuit is a dedicated hardware, the processing circuit 71 corresponds to, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or a combination of these. The functions of each unit of the global learning unit 301 and the local learning unit 350 may be realized by the processing circuit 71, or the functions of each unit may be realized by the processing circuit 71 collectively.

[0120] When the processing circuit is a CPU 72, the functions of the global learning unit 301 and the local learning unit 350 are realized by software, firmware, or a combination of software and firmware. The software and firmware are written as programs and stored in the memory 73. The processing circuit realizes the functions of each unit by reading and executing the programs recorded in the memory 73. That is, the learning device 300 includes a memory for storing a program that, when executed by the processing circuit, results in the execution of each step shown in FIG. 13. It can also be said that these programs cause a computer to execute the procedures and methods of the global learning unit 301 and the local learning unit 350. Here, examples of the memory 73 include non-volatile or volatile semiconductor memories such as RAM (Random Access Memory), ROM (Read Only Memory), flash memory, EPROM (Erasable Programmable ROM), and EEPROM (Electrically EPROM), magnetic disks, flexible disks, optical disks, compact disks, mini disks, and DVDs (Digital Versatile Discs).

[0121] It should be noted that the functions of global learning unit 301 and local learning unit 350 may be partially realized by dedicated hardware and partially realized by software or firmware. For example, the functions of global learning unit 301 may be realized by a processing circuit as dedicated hardware, and the functions of local learning unit 350 may be realized by the processing circuit reading and executing a program stored in memory 73.

[0122] Thus, the processing circuitry may implement the above-described functions through hardware, software, firmware, or a combination of these.

[0123] <State inference device 600> Next, a description will be given of state inference device 600 according to embodiment 1. Fig. 15 is a diagram showing an example of the configuration of state inference device 600 according to embodiment 1. State inference device 600 includes an acquisition unit 601, a data selection unit 602, an evaluation unit 603, and a feedback information generation unit 604, for example, as shown in Fig. 15.

[0124] State inference device 600 detects an abnormality in the target device by inferring the state of the target device using a local model indicated by the data (local model data) recorded in recording unit 100 by learning device 300. In the following description, it is assumed that the abnormality in the target device is deterioration of the target device.

[0125] (Acquisition part 601) The acquiring unit 601 acquires vibration data A1 from the vibration sensor 50 attached to the target device. This vibration data A1 is data indicating a time change in a vibration amplitude value of the target device acquired from the target device by the vibration sensor 50 attached to the target device. Note that the vibration data A1 may be data indicating a time change in a feature of the vibration amplitude value. In this case, the feature of the vibration amplitude value may be, for example, an RMS value of the vibration amplitude value. Note that, in the following description, a case where the vibration data is an RMS value of the vibration amplitude value will be described as an example.

[0126] The acquiring unit 601 also acquires control information data B1 to Bn from the control information recording device 60. Here, the control information data B1 to Bn are data indicating time changes in the control information, as shown in the second to fourth graphs from the top in FIG. 3, and are data synchronized in time with the vibration data. Also, n is the number of pieces of control information. Here, the control information is a parameter that determines the operating conditions of the target device, such as the number of rotations when the target device is a rotating machine, and the current value of the driving power of the rotating machine. Here, the control information recording device 60 is a dedicated device for recording the control information data B1 to Bn.

[0127] The acquiring unit 601 outputs the collected data, which is a combination of the acquired vibration data A1 and the acquired control information data B1 to Bn, to the data selecting unit 602 as data D1.

[0128] (Data selection unit 602) The data selection unit 602 refers to the recording unit 100 and acquires the local model data MA1 to MAn and the control condition data MB1 to MBn from the recording unit 100. Here, n is the number of local models, and the local model data and the control condition data correspond one-to-one. For ease of understanding, it is assumed here that n=1.

[0129] The data selection unit 602 extracts vibration data and control information data that satisfy the control conditions indicated by the acquired control condition data MB1 from the vibration data and control information data included in the above-mentioned data D1, and outputs data combining each extracted data with the local model data MA1 and the control condition data MB1 to the evaluation unit 603 as data D2.

[0130] (Evaluation unit 603) The evaluation unit 603 includes a degradation degree calculation unit 631, a parameter adjustment unit 632, and an image output unit 633, as shown in FIG.

[0131] (Deterioration level calculation unit 631) The degradation degree calculation unit 631 acquires data D2 from the data selection unit 602. The degradation degree calculation unit 631 analyzes the acquired data D2 to calculate the degradation degree of the target device. Specifically, the degradation degree calculation unit 631 inputs, for example, an arbitrary value (e.g., rotation speed=500) of the control information data B1 included in the data D2 to the local model indicated by the local model data MA1 included in the data D2. Based on the input value, the local model outputs vibration data corresponding to the value (e.g., RMS value=1.5).

[0132] Then, the degradation degree calculation unit 631 compares the vibration data output from the local model with the vibration data included in the data D2 and corresponding to the arbitrary value, and calculates the error between them. Then, the degradation degree calculation unit 631 calculates the degradation degree of the target device by comparing the calculated error with a predetermined threshold. Note that the degradation degree calculation unit 631 can calculate the degradation degree using, for example, the mean absolute error (MAPE) or T2 Hotelling. The degradation degree calculation unit 631 outputs data indicating the calculated degradation degree to the image output unit 633 as a state descriptor.

[0133] (Image output unit 633) The image output unit 633 acquires the state descriptor from the deterioration degree calculation unit 631. The image output unit 633 also acquires the data D2 from the data selection unit 602. The image output unit 633 then generates data showing a comparison image, for example, as shown in FIG. 17, using each of the acquired data. In FIG. 17, the left side is an image showing the distribution of vibration data (learning data) used when constructing the local model, and the right side is an image showing the distribution of vibration data obtained by inputting the control information data B1 actually acquired from the target device into the local model. With such an image, the user can easily grasp how much the distribution of the vibration data obtained by inputting the control information data B1 actually acquired from the target device into the local model deviates from the distribution of the vibration data (learning data) used when constructing the local model. The image output unit 633 outputs the generated data showing the comparison image to the third external evaluation device 700.

[0134] The third external evaluation device 700 acquires data indicating a comparison image from the image output unit 633. The third external evaluation device 700 displays a comparison image as shown in Fig. 17 on a display unit (not shown) based on the acquired data. The user checks the comparison image displayed on the display unit, and adjusts parameters using the third external evaluation device 700 as necessary.

[0135] For example, as shown in Fig. 17, a slight difference may occur between the two distributions due to an accidental cause. In this case, the deterioration degree may change due to a slight difference caused by an accidental cause unrelated to deterioration. For example, in the example of Fig. 17, the deterioration degree of the target device is calculated as "18% deterioration" even though it is not actually very deteriorated. Therefore, the user adjusts the parameters to adjust for such a slight difference.

[0136] For example, the user adjusts the position of a prediction line 1701 obtained by a local model shown on the left side of Fig. 17 and the position of a line 1702 indicating the boundary of a confidence interval set for the prediction line 1701. In this case, the user adjusts the position of each line by visually checking the difference between the left and right distribution maps in Fig. 17, for example, or adjusts the position of each line by calculating the difference between the average values ​​of the left and right vibration data.

[0137] Alternatively, the user adjusts the interval between a prediction line 1701 obtained by a local model shown on the left side of Fig. 17 and a line 1702 indicating the boundary of a confidence interval set for the prediction line 1701. In this case as well, the user adjusts the interval by visually checking the ratio of variations in the vibration data in the left and right distribution maps of Fig. 17, for example, or by taking the magnification of the standard deviation values ​​of the left and right vibration data.

[0138] The third external evaluation device 700 outputs data indicating the adjustment content input by the user to the parameter adjustment unit 632 as an adjustment descriptor D4. The adjustment descriptor D4 includes regression model data to be adjusted, control condition data, data necessary for model adjustment (specifically, correction values ​​of regression coefficients), and the like. In particular, data necessary for model adjustment is also called a parameter adjuster. The adjustment descriptor D4 also includes a judgement input by the user for determining whether or not to output the adjustment descriptor D4 to the feedback information generation unit 604. For example, if the judgement is 1, it indicates that the adjustment descriptor D4 is to be output to the feedback information generation unit 604, and if the judgement is 0, it indicates that the adjustment descriptor D4 is not to be output to the feedback information generation unit 604.

[0139] It should be noted that, among the adjustment descriptors D4, the parameter adjusters are input by the user when, for example, the user visually adjusts the left and right distribution diagrams in FIG. 17; however, in other cases (for example, when the difference between the average values ​​of the left and right vibration data is calculated to adjust the positions of each line), the parameter adjusters can be calculated automatically by, for example, the parameter adjustment unit 632, so they do not necessarily have to be input by the user.

[0140] (Parameter adjustment unit 632) The parameter adjustment unit 632 acquires the adjustment descriptor D4 from the third external evaluation device 700. The parameter adjustment unit 632 outputs the acquired adjustment descriptor D4 to the degradation degree calculation unit 631, and instructs the degradation degree calculation unit 631 to adjust the local model based on the adjustment descriptor D4. In response to this instruction, the degradation degree calculation unit 631 adjusts the local model, and recalculates the degradation degree by the above-mentioned procedure using the adjusted local model. In addition, the degradation degree calculation unit 631 outputs data indicating the recalculated degradation degree to the image output unit 633 as a state descriptor. Thereafter, the image output unit 633, the third external evaluation device 700, and the parameter adjustment unit 632 repeat the above-mentioned processes.

[0141] When the parameter adjustment unit 632 no longer acquires the adjustment descriptor D4 from the third external evaluation device 700 in the above repetition, the parameter adjustment unit 632 instructs the image output unit 633 to display the final calculation result of the deterioration degree on the display unit of the third external evaluation device 700.

[0142] Furthermore, the parameter adjustment unit 632 checks the content of the judge included in the acquired adjustment descriptor D4. When the content of the judge indicates that the adjustment descriptor D4 is to be output to the feedback information generation unit 604, the parameter adjustment unit 632 outputs the adjustment descriptor D4 as data D5 to the feedback information generation unit 604. On the other hand, when the content of the judge indicates that the adjustment descriptor D4 is not to be output to the feedback information generation unit 604, the parameter adjustment unit 632 does not output the adjustment descriptor D4 to the feedback information generation unit 604.

[0143] (Feedback information generating unit 604) The feedback information generating unit 604 acquires data D5 from the parameter adjusting unit 632. The feedback information generating unit 604 generates feedback information D6 based on the acquired data D5, and causes the recording unit 100 to record the generated feedback information D6. The feedback information D6 includes regression model data to be adjusted, control condition data, data required for model adjustment (specifically, correction values ​​of regression coefficients), and the like, almost similar to the adjustment descriptor D4. The feedback information generating unit 604 causes the recording unit 100 to record the feedback information D6 as information separate from the local model data MA1 and control condition data MB1 already recorded in the recording unit 100.

[0144] Thereafter, the user may appropriately reflect the feedback information D6 recorded in the recording unit 100 in the local model data MA1 and the control condition data MB1. This causes the local model data MA1 and the control condition data MB1 to be updated based on the feedback information D6, and it is possible to reduce the possibility of detection errors arising from a difference (for example, a difference due to the above-mentioned accidental cause) that is unknown at the time of constructing the second regression model between the data actually acquired from the target device and the learning data used when the second regression model is constructed.

[0145] Next, an example of the operation of state inference device 600 according to the first embodiment will be described with reference to the flowchart shown in FIG.

[0146] First, the acquiring unit 601 receives vibration data from the vibration sensor 50 attached to the target device. The acquiring unit 601 also acquires control information data from the control information recording device 60 (step ST21).

[0147] Next, the data selection unit 602 acquires the local model data and the control condition data from the recording unit 100, and extracts the vibration data and the control information data that satisfy the control conditions indicated by the acquired control condition data from the vibration data and the control information data acquired in step ST21 (step ST22).

[0148] Next, the deterioration level calculation unit 631 calculates the deterioration level of the target device by using the data extracted in step ST22 (step ST23).

[0149] Next, the image output unit 633 generates data representing a comparison image, for example, as shown in Fig. 17, using the calculation result in step ST23 (step ST24). The image output unit 633 outputs the generated data representing the comparison image to the third external evaluation device 700.

[0150] Next, the parameter adjustment unit 632 judges whether or not the adjustment descriptor D4 has been acquired from the third external evaluation device 700 (step ST25). As a result, when the parameter adjustment unit 632 judges that the adjustment descriptor D4 has been acquired from the third external evaluation device 700 (step ST25; Yes), the parameter adjustment unit 632 outputs the adjustment descriptor D4 to the degradation degree calculation unit 631 and instructs the degradation degree calculation unit 631 to adjust the local model based on the adjustment descriptor D4. The degradation degree calculation unit 631 adjusts the local model based on the adjustment descriptor D4 (step ST26). After that, the process returns to step ST23.

[0151] On the other hand, if the parameter adjustment section 632 determines that the adjustment descriptor D4 has not been acquired from the third external evaluation device 700 (step ST25; No), the process proceeds to step ST26.

[0152] In step ST26, the parameter adjustment unit 632 judges whether or not the adjustment descriptor D4 has been acquired even once from the third external evaluation device 700 (step ST26). As a result, when the parameter adjustment unit 632 judges that the adjustment descriptor D4 has not been acquired even once from the third external evaluation device 700 (step ST26; No), the process proceeds to step ST29.

[0153] On the other hand, if the parameter adjustment unit 632 determines that it has previously acquired the adjustment descriptor D4 at least once from the third external evaluation device 700 (step ST26; Yes), it checks the contents of the judgement included in the last acquired adjustment descriptor D4. Then, if the contents of the judgement indicate that the adjustment descriptor D4 should be output to the feedback information generation unit 604, it outputs the last acquired adjustment descriptor D4 to the feedback information generation unit 604 as data D5.

[0154] The feedback information generating unit 604 generates feedback information D6 based on the data D5 acquired from the parameter adjusting unit 632 (step ST27), and causes the generated feedback information D6 to be recorded in the recording unit 100 (step ST28). After that, the process proceeds to step ST29.

[0155] In step ST29, the image output unit 633 generates data indicating the final calculation result of the deterioration degree of the target equipment, and outputs the generated data to the third external evaluation device 700, thereby causing the final calculation result of the deterioration degree of the target equipment to be displayed on the display unit (step ST29).

[0156] Next, an example of a hardware configuration of a state inference device 600 according to the first embodiment will be described with reference to Fig. 19. The functions of an acquisition unit 601, a data selection unit 602, an evaluation unit 603, and a feedback information generation unit 604 in the state inference device 600 are realized by processing circuits. The processing circuit may be dedicated hardware as shown in Fig. 19A, or may be a CPU (also referred to as a Central Processing Unit, a processing unit, an arithmetic unit, a microprocessor, a microcomputer, a processor, or a DSP (Digital Signal Processor)) 82 that executes a program stored in a memory 83 as shown in Fig. 19B.

[0157] When the processing circuit is a dedicated hardware, the processing circuit 81 corresponds to, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or a combination of these. The functions of each of the acquisition unit 601, the data selection unit 602, the evaluation unit 603, and the feedback information generation unit 604 may be realized by the processing circuit 81 individually, or the functions of each unit may be realized by the processing circuit 81 collectively.

[0158] When the processing circuit is a CPU 82, the functions of the acquisition unit 601, the data selection unit 602, the evaluation unit 603, and the feedback information generation unit 604 are realized by software, firmware, or a combination of software and firmware. The software and firmware are written as programs and stored in the memory 83. The processing circuit realizes the functions of each unit by reading and executing the programs recorded in the memory 83. That is, the state inference device 600 includes a memory for storing a program that, when executed by the processing circuit, results in the execution of each step shown in FIG. 18, for example. It can also be said that these programs cause a computer to execute the procedures and methods of the acquisition unit 601, the data selection unit 602, the evaluation unit 603, and the feedback information generation unit 604. Here, examples of memory 83 include non-volatile or volatile semiconductor memory such as RAM (Random Access Memory), ROM (Read Only Memory), flash memory, EPROM (Erasable Programmable ROM), EEPROM (Electrically EPROM), magnetic disk, flexible disk, optical disk, compact disk, mini disk, or DVD (Digital Versatile Disc), etc.

[0159] It should be noted that the functions of the acquisition unit 601, the data selection unit 602, the evaluation unit 603, and the feedback information generation unit 604 may be partially realized by dedicated hardware and partially realized by software or firmware. For example, the acquisition unit 601 may be realized by a processing circuit as dedicated hardware, and the data selection unit 602, the evaluation unit 603, and the feedback information generation unit 604 may be realized by the processing circuit reading and executing a program stored in the memory 83.

[0160] Thus, the processing circuitry may implement the above-described functions through hardware, software, firmware, or a combination of these.

[0161] As described above, according to the first embodiment, the learning device 300 includes: a global model construction unit 304 that constructs a first regression model (global model) that fits the learning data and a first explanatory variable x1 based on learning data that can be explained by a plurality of explanatory variables and a first explanatory variable x1 that is an externally specified explanatory variable and is one of the plurality of explanatory variables; a second variable selection unit 360 that selects a second explanatory variable x2 from the plurality of explanatory variables, the second variable selection unit 360 selecting a second explanatory variable x2 that is separable from the learning data for target data that is deemed to be varied based on the first regression model constructed by the global model construction unit 304; and a local model construction unit 354 that constructs a second regression model (local model) that fits the learning data and the first explanatory variable x1 using the learning data after the target data has been separated, based on the second explanatory variable x2 selected by the second variable selection unit 360 and the first explanatory variable x1. As a result, the learning device 300 of embodiment 1 can reduce the amount of work required for learning when using variable data collected from a target device to learn a model for detecting anomalies in the target device, compared to the conventional method.

[0162] The second variable selection unit 360 also includes a filter processing unit 351 that classifies the learning data into target data (Data A) considered to be scattered and non-target data (Data B) considered not to be scattered based on the first regression model constructed by the global model construction unit 304, a range selection unit 352 that selects a predetermined range from among the possible ranges of the first explanatory variable x1 based on the target data and non-target data classified by the filter processing unit 351, and a second variable selection processing unit 353 that selects the second explanatory variable x2 using the learning data included in the predetermined range selected by the range selection unit 352. This allows the learning device 300 according to the first embodiment to appropriately select the second explanatory variable x2 based on the first regression model and the learning data.

[0163] Furthermore, the filter processing unit 351 sets the learning data located outside a predetermined confidence interval centered on the prediction line, which is set for the prediction line obtained based on the first regression model constructed by the global model construction unit 304, as target data, and sets the learning data located inside the predetermined confidence interval centered on the prediction line as non-target data. This enables the learning device 300 according to the first embodiment to easily classify the learning data into target data (Data A) considered to be scattered and non-target data (Data B) considered not to be scattered.

[0164] The range selection unit 352 also includes a distribution calculation unit 361 that calculates, for each of the target data and non-target data, a probability distribution indicating how frequently the target data and non-target data classified by the filter processing unit 351 appear with respect to the first explanatory variable x1, and a distribution difference comparison unit 362 that calculates the difference between the probability distribution of the target data calculated by the distribution calculation unit 361 and the probability distribution of the non-target data calculated by the distribution calculation unit 361, and selects, as a predetermined range, a range of the first explanatory variable x1 in which the calculated difference is equal to or greater than a predetermined value. This allows the learning device 300 according to the first embodiment to easily select a predetermined range of the first explanatory variable x1 used to select the second explanatory variable x2.

[0165] Furthermore, the distribution difference comparing unit 362 selects a predetermined range from the search width S received from outside, which indicates a range of the first explanatory variable x1 in which the proportion of non-target data is assumed to be relatively high. This allows the learning device 300 according to the first embodiment to appropriately select the predetermined range of the first explanatory variable x1, based on the search width S received from outside.

[0166] The second variable selection unit 353 generates a probability distribution indicating how frequently the learning data included in the predetermined range selected by the range selection unit 352 appears with respect to a certain explanatory variable, and selects, as the second explanatory variable x2, an explanatory variable such that, in the generated probability distribution, a ratio of non-target data to the number of learning data included in the second range X is equal to or greater than a predetermined value, where the range of the first explanatory variable x1 in which the ratio of non-target data to the number of learning data included in the second range X is equal to or greater than a predetermined value. This allows the learning device 300 according to the first embodiment to select the second explanatory variable x2 appropriately and efficiently.

[0167] The local model construction unit 354 further includes a region evaluation unit 363 that generates data showing an image in which a region where target data appears and a region where non-target data appears are shown among the regions defined by a combination of the second explanatory variable x2 selected by the second variable selection unit 360 and the first explanatory variable x1, and a model construction unit 364 that receives a region specified from outside based on the image shown by the data generated by the region evaluation unit 363 among the regions defined by a combination of the first explanatory variable x1 and the second explanatory variable x2, and constructs a second regression model using the learning data included in the received region. This allows the learning device 300 according to the first embodiment to construct a second regression model reflecting an external (e.g., user) intention.

[0168] Furthermore, the learning device 300 includes a model evaluation unit 305 that receives an external evaluation of the first regression model constructed by the global model construction unit 304, and a model evaluation unit 355 that receives an external evaluation of the second regression model constructed by the local model construction unit 354. This allows the learning device 300 according to the first embodiment to obtain external (e.g., user) evaluations of the first regression model and the second regression model.

[0169] Furthermore, the global model construction unit 304 includes a model update unit 312 that reconstructs a first regression model that fits the learning data and a new first explanatory variable x1, which is specified from the outside and is one of the multiple explanatory variables, based on the learning data and the new first explanatory variable x1, when the evaluation received by the model evaluation unit 355 indicates that a desired second regression model does not exist. Thereby, the learning device 300 according to the first embodiment can reconstruct the first regression model from the first regression model when a desired second regression model has not been constructed.

[0170] Furthermore, according to the first embodiment, the state inference device 600 includes a global model construction unit 304 that constructs a first regression model (global model) that fits the learning data explainable by a plurality of explanatory variables and a first explanatory variable x1 that is an externally specified explanatory variable and is one of the plurality of explanatory variables, and a second variable selection unit 360 that selects a second explanatory variable x2 from the plurality of explanatory variables, and selects, from the learning data, target data that is deemed to be varied based on the first regression model constructed by the global model construction unit 304, from the learning data. The learning device 300 includes a second variable selection unit 360 that selects a second explanatory variable x2 separable from the target data, and a local model construction unit 354 that constructs a second regression model (local model) that fits the learning data and the first explanatory variable x1 using the learning data after the target data has been separated, based on the second explanatory variable x2 selected by the second variable selection unit 360 and the first explanatory variable x1. The state inference device 600 infers a state of the target device using the second regression model constructed by the local model construction unit 354 and data corresponding to the learning data and the first explanatory variable acquired from the target device. This allows the state inference device 600 according to the first embodiment to accurately infer the state of the target device.

[0171] Moreover, state inference device 600 includes feedback information generating unit 604 that corrects the regression coefficients in the second regression model based on a correction value received from outside and used to correct the regression coefficients in the second regression model. This allows state inference device 600 according to the first embodiment to reduce the possibility of detection errors arising from a difference, which is unknown at the time of construction, between data actually acquired from the target device and learning data used when constructing the second regression model.

[0172] Furthermore, according to the first embodiment, the condition monitoring system 1000 includes a global model construction unit 304 that constructs a first regression model (global model) that fits the learning data explainable by a plurality of explanatory variables and a first explanatory variable x1 that is an externally specified explanatory variable and is one of the plurality of explanatory variables, and a second variable selection unit 360 that selects a second explanatory variable x2 from the plurality of explanatory variables, and selects target data that is considered to be varied based on the first regression model constructed by the global model construction unit 304 from the learning data as a second regression model that can be separated from the learning data. The learning device 300 includes a second variable selection unit 360 that selects an explanatory variable x2, and a local model construction unit 354 that constructs a second regression model (local model) that fits between the learning data and the first explanatory variable x1 using the learning data after the target data is separated based on the second explanatory variable x2 selected by the second variable selection unit 360 and the first explanatory variable x1, and a state inference device 600 that infers a state of the target device using the second regression model constructed by the local model construction unit 354 and data corresponding to the learning data and the first explanatory variable x1 acquired from the target device. As a result, the state monitoring system 1000 according to the first embodiment can reduce the number of steps required for learning compared to the conventional method when learning a model for detecting an abnormality of the target device using data with variations collected from the target device, and can accurately infer the state of the target device using the model.

[0173] Finally, a suitable application example of the learning device 300 and the state inference device 600 according to the first embodiment will be described. The learning device 300 according to the first embodiment is suitable for use in a monitoring system for an electric motor mounted on a railway vehicle, for example. In an electric motor mounted on a railway vehicle, a large amount of control information, such as brake information, rotation speed information, current information, and voltage information of the electric motor, is present in addition to vibration data. When constructing a system for monitoring vibration data reflecting the state of the electric motor under control information, in order to utilize the knowledge of a user (for example, knowledge that vibration and rotation speed are closely related and that high-frequency vibration characteristics are likely to appear at low speeds), a model (global model) in which the rotation speed is an explanatory variable is first constructed by the global model construction unit 304. Next, in order to improve the accuracy of the model, a model (local model) is constructed after the user specifies the range of the rotation speed and narrows down the conditions using other control information that can exclude data that deviates from the global model. As a result, in the monitoring system, it is possible to incorporate the knowledge of a user into the construction of a model, reduce the process of model construction and evaluation using explanatory variables and conditions that are considered unnecessary for deterioration detection, and efficiently construct a model.

[0174] Similarly to learning device 300, state inference device 600 according to embodiment 1 is also suitable for use in, for example, a monitoring system for an electric motor mounted on a railway vehicle. For example, state inference device 600 according to embodiment 1 may be further provided with an alarm device, and configured to output an alarm to a user of the monitoring system when state inference device 600 determines, based on vibration data acquired from vibration sensor 50 attached to the target device, that the target device is not the same object as the object set as a monitoring target. State inference device 600 according to embodiment 1 is thus applicable to a monitoring system.

[0175] Similarly to the learning device 300 and the state inference device 600, the state monitoring system 1000 according to the first embodiment is also suitable for use in a monitoring system for an electric motor mounted on a railway vehicle, for example.

[0176] In addition, the present disclosure allows modification of any of the components of the embodiment, or omission of any of the components of the embodiment. For example, in the above description, the learning data, which is the objective variable, is vibration data, and the explanatory variable explaining the objective variable is control information data. However, the learning data, which is the objective variable, and the explanatory variable are not limited to the above example, and may be any type of data as long as the explanatory variable explains the objective variable.

[0177] Also, in the above description, an example has been described in which recording unit 100 is provided separately from learning device 300 and state inference device 600. However, the present invention is not limited to this, and recording unit 100 may be built into, for example, either learning device 300 or state inference device 600. Alternatively, the recording unit 100 may be built into any one of the first external evaluation device 400, the second external evaluation device 500, and the third external evaluation device 700.

[0178] In the above description, an example has been described in which the first external evaluation device 400, the second external evaluation device 500, and the third external evaluation device 700 are provided separately. However, the present invention is not limited to this, and the functions of the respective devices may be integrated into one device, or the functions of any two devices may be integrated into one device. [Explanation of symbols]

[0179] 50 vibration sensor, 60 control information recording device, 71 processing circuit, 72 CPU, 73 memory, 81 processing circuit, 82 CPU, 83 memory, 100 recording unit, 200 learning data recording unit, 300 learning device, 301 global learning unit, 302 data extraction unit, 303 explanatory variable acquisition unit, 304 global model construction unit, 305 model evaluation unit (first model evaluation unit), 311 model construction unit, 312 model update unit, 313 image output unit, 314 model determination unit, 350 local learning unit, 351 filter processing unit, 352 range selection unit, 353 second variable selection processing unit (variable selection processing unit), 354 local model construction unit, 355 model evaluation unit (second model evaluation unit), 360 second variable selection unit (variable selection unit), 361 distribution calculation unit, 362 distribution difference comparison unit, 363 Area evaluation unit, 364 model construction unit, 365 prediction error calculation unit, 366 image output unit, 367 model determination unit, 390 intermediate recording unit, 400 first external evaluation device, 500 second external evaluation device, 501 prediction line, 502 line indicating boundary of confidence interval, 600 state inference device, 601 acquisition unit, 602 data selection unit, 603 evaluation unit, 604 feedback information generation unit, 631 deterioration degree calculation unit, 632 parameter adjustment unit, 633 image output unit, 700 third external evaluation device, 1000 state monitoring system, 1701 prediction line, 1702 line indicating boundary of confidence interval, A1 vibration data, B1 control information data, 210 vibration DB, 220 control information DB, U1 area, U2 area, U3 area.

Claims

1. a global model construction unit that constructs a first regression model that fits the learning data and a first explanatory variable, the first explanatory variable being one of the plurality of explanatory variables and that is externally specified, based on the learning data that can be explained by the first explanatory variable; a variable selection unit that selects a second explanatory variable from the plurality of explanatory variables, the variable selection unit selecting a second explanatory variable that is separable from the training data for target data that is deemed to be varied based on the first regression model constructed by the global model construction unit; a local model construction unit that constructs a second regression model that fits the learning data and the first explanatory variables, using the learning data after the target data has been separated, based on the second explanatory variables selected by the variable selection unit and the first explanatory variables; A learning device equipped with

2. The variable selection unit: a filter processing unit that classifies the learning data into the target data that is considered to be scattered and non-target data that is considered not to be scattered based on a first regression model constructed by the global model construction unit; a range selection unit that selects a predetermined range from among possible ranges of the first explanatory variable based on the target data and the non-target data classified by the filter processing unit; a variable selection unit that selects the second explanatory variable by using learning data included in the predetermined range selected by the range selection unit; 2. The learning device according to claim 1, further comprising:

3. The filter processing unit includes:

3. The learning device according to claim 2, characterized in that learning data located outside a predetermined confidence interval centered on a prediction line obtained based on the first regression model constructed by the global model construction unit is set as the target data, and learning data located inside a predetermined confidence interval centered on the prediction line is set as the non-target data.

4. The range selection unit is a distribution calculation unit that calculates a probability distribution indicating how frequently the target data and the non-target data classified by the filter processing unit appear with respect to the first explanatory variable, for each of the target data and the non-target data; a distribution difference comparison unit that calculates a difference between the probability distribution of the target data calculated by the distribution calculation unit and the probability distribution of the non-target data calculated by the distribution calculation unit, and selects, as the predetermined range, a range of the first explanatory variable in which the calculated difference is equal to or greater than a predetermined value; 4. The learning device according to claim 2, further comprising:

5. The distribution difference comparison unit The learning device according to claim 4, characterized in that the specified range is selected from a search range received from outside, the search range indicating a range within the range of the first explanatory variable in which the proportion of non-target data is assumed to be relatively high.

6. The variable selection processing unit: a probability distribution is generated that indicates how frequently learning data included in a predetermined range selected by the range selection unit appears with respect to a certain explanatory variable, and in the generated probability distribution, a range of a first explanatory variable in which a ratio of the target data to the number of learning data is equal to or greater than a predetermined value is defined as a first range, and a range of the first explanatory variable excluding the first range is defined as a second range; The learning device according to claim 2 or 3, characterized in that an explanatory variable in which a proportion of the non-target data among the learning data included in the second range is equal to or greater than a predetermined value is selected as the second explanatory variable.

7. The local model construction unit an area evaluation unit that generates data showing an image showing an area in which the target data considered to be scattered appears and an area in which non-target data considered not to be scattered appears, among areas defined by a combination of the second explanatory variable selected by the variable selection unit and the first explanatory variable; a model construction unit that receives an area designated from outside based on an image represented by data generated by the area evaluation unit, among areas defined by a combination of the first explanatory variable and the second explanatory variable, and constructs the second regression model using learning data included in the received area; The learning device according to any one of claims 1 to 3, further comprising:

8. a first model evaluation unit that receives an external evaluation of the first regression model constructed by the global model construction unit; a second model evaluation unit that receives an external evaluation of the second regression model constructed by the local model construction unit; The learning device according to any one of claims 1 to 3, further comprising:

9. The global model construction unit and a model updating unit configured to reconstruct a first regression model that fits the learning data and a new first explanatory variable that is externally specified and is one of the plurality of explanatory variables, based on the learning data and a new first explanatory variable when the evaluation received by the second model evaluation unit indicates that a desired second regression model does not exist.

9. The learning device according to claim 8.

10. a global model construction unit that constructs a first regression model that fits the learning data and a first explanatory variable, the first explanatory variable being one of the plurality of explanatory variables and that is externally specified, based on the learning data that can be explained by the first explanatory variable; a variable selection unit that selects a second explanatory variable from the plurality of explanatory variables, the variable selection unit selecting a second explanatory variable that is separable from the training data for target data that is deemed to be varied based on the first regression model constructed by the global model construction unit; a local model construction unit that constructs a second regression model that fits the learning data and the first explanatory variables, using the learning data after the target data has been separated, based on a second explanatory variable selected by the variable selection unit and the first explanatory variable; and A state inference device that infers a state of a target device using data corresponding to the learning data and data corresponding to the first explanatory variable, both obtained from the target device.

11. a feedback information generating unit that corrects the regression coefficient in the second regression model based on a correction value received from an external source and that is used to correct the regression coefficient in the second regression model.

11. The state inference device according to claim 10.

12. a global model construction unit that constructs a first regression model that fits the learning data and a first explanatory variable, the first explanatory variable being one of the plurality of explanatory variables and that is externally specified, based on the learning data that can be explained by the first explanatory variable; a variable selection unit that selects a second explanatory variable from the plurality of explanatory variables, the variable selection unit selecting a second explanatory variable that is separable from the training data for target data that is deemed to be varied based on the first regression model constructed by the global model construction unit; a local model construction unit that constructs a second regression model that fits between the learning data and the first explanatory variables, using the learning data after the target data has been separated, based on a second explanatory variable selected by the variable selection unit and the first explanatory variable; a state inference device that infers a state of the target device by using a second regression model constructed by the local model construction unit, and data corresponding to the learning data and data corresponding to the first explanatory variable, which are acquired from the target device; A condition monitoring system with

13. A learning method using a learning device, comprising: a step of constructing a first regression model that fits the learning data and a first explanatory variable, the first explanatory variable being one of the plurality of explanatory variables, based on the learning data that can be explained by the plurality of explanatory variables, by a global model construction unit; a step of selecting a second explanatory variable from the plurality of explanatory variables, in which a variable selection unit selects a second explanatory variable capable of separating, from the learning data, target data that is deemed to be varied based on a first regression model constructed by the global model construction unit; a local model construction unit constructing a second regression model that fits between the training data and the first explanatory variables, using the training data from which the target data has been separated, based on the second explanatory variables selected by the variable selection unit and the first explanatory variables; A learning method that has

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