Learning systems, methods, and programs

Abstract

To appropriately set federated learning conditions in which local data is considered.SOLUTION: According to one embodiment, a learning system includes a plurality of local devices and a server. The local devices each include a local determination unit to determine a federated local training condition indicating a training condition in federated learning of a local model based on preliminary local training information including a preliminary local training condition and a preliminary local training result in a case where a model is preliminarily trained using local data. The server includes a global determination unit to determine a global training condition of a global model based on the preliminary local training information.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] Embodiments of the present invention relate to learning systems, methods, and programs. [Background technology]

[0002] One learning method called Federated Learning involves training a machine learning model (local model) based on training data acquired from multiple local devices, and then sending the parameters of the trained local models to a server. The server aggregates and integrates the parameters from each local model and updates the machine learning model (global model) on the server. The updated global model's parameters are then distributed to each of the multiple local devices. This series of processes is repeated. Federated Learning distributes the computational load because training is performed on multiple local devices. Furthermore, since only parameters are exchanged with the server, the training data itself is not exchanged. Therefore, it offers the advantages of high privacy confidentiality and low communication costs.

[0003] When using neural networks as machine learning models, it is crucial to appropriately set learning conditions (tuning parameters) such as the learning rate, regularization strength, and optimizer. In associative learning, the learning conditions for both the local model and the global model must be set according to the number of devices, and setting these values ​​appropriately becomes more difficult as the number of devices increases. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] U.S. Patent No. 10402469 [Overview of the project] [Problems that the invention aims to solve]

[0005] The present disclosure has been made to solve the above-described problems, and an object thereof is to provide a learning system, method, and program capable of appropriately setting collaborative learning conditions in consideration of local data.

Means for Solving the Problems

[0006] The learning system according to the present embodiment includes a plurality of local devices and a server. Each of the plurality of local devices includes a local determination unit that determines collaborative local learning conditions indicating learning conditions in the collaborative learning of the local model based on pre-local learning information including pre-local learning conditions and pre-local learning results when the model is pre-learned with local data. The server includes a global determination unit that determines global learning conditions of the global model based on the pre-local learning information.

Brief Description of the Drawings

[0007] [Figure 1] Conceptual diagram showing the learning system according to the present embodiment. [Figure 2] Flowchart showing the learning process of the learning system according to the present embodiment. [Figure 3] Block diagram showing an example of the hardware configuration of the local device and the server.

Modes for Carrying Out the Invention

[0008] Hereinafter, the learning system, method, and program according to the present embodiment will be described in detail with reference to the drawings. In the following embodiments, portions denoted by the same reference numerals perform the same operations, and duplicate explanations will be omitted as appropriate.

[0009] The learning system according to the present embodiment will be described with reference to the block diagram of FIG. 1. The learning system according to this embodiment includes local devices 10A, local device 10B, and server 11, which are respectively connected via network NW so as to be able to transmit and receive data. Here, as an example, two local devices 10A and local device 10B are shown, but three or more local devices 10 may be included. Hereinafter, in the case of descriptions common to each local device, it is simply referred to as local device 10.

[0010] Each local device 10 includes a local storage unit 101, a local determination unit 102, a local learning unit 103, and a local communication unit 104.

[0011] The local storage unit 101 stores local data, local models, learned models, etc., in addition to pre-local learning information. The pre-local learning information is only the local data held by each local device 10, and is information when the model is learned in advance, and includes pre-local learning conditions and a pre-local learning result that is a learning result based on the pre-local learning conditions. Pre-local training conditions are the training conditions for training the model in advance, and include settings such as learning rate, regularization, mini-batch size, initialization method or model weights, optimizer, dataset classification information, and architectural structure. The learning rate is, for example, the initial learning rate and learning rate schedule. Regularization is, for example, L1 regularization intensity, L2 regularization intensity, dropout number, orthogonal regularization intensity, or its schedule. The initialization method or model weights are, for example, information about random numbers and the lottery hypothesis. The optimizer is, for example, an update formula such as SGD (Stochastic Gradient Decent), Adam, or LARS (Layer-wise Adaptive Rate Scaling), or its tuning parameters. The distribution information of the dataset is a quantitative value of the nature and difficulty of the data obtained by, for example, the number of data points, mean, variance, Shannon information, and V-usable information. The architecture structure indicates the type of model to be used, such as a CNN (Convolutional Neural Network), SVM (Support Vector Machine), Random Forest, or a skip-structure model like ResNet, DenseNet, or U-net. The architecture structure should be selected based on the task at hand. The pre-training local training results include the model's recognition rate, loss, pruning results, and NTK (Neural Tangent Kernel) information. The model's recognition rate and loss, respectively, show the results for the recognition rate curves at the final iteration, the best-performing iteration, and intermediate stages of the training data (local data and test data). The pruning results indicate weights, channels, and layers that can be removed from the neural network during or after training. NTK information shows information such as kernels that indicate how the overall weights or features of the neural network change during training. The pre-local learning information serves as a baseline for users or administrators who own each local device 10 before conducting federated learning. This information is crucial for verifying performance improvements through federated learning and estimating target performance. Therefore, by appropriately setting the pre-local learning conditions and performing appropriate pre-local learning, even greater effectiveness can be expected in subsequent federated learning.

[0012] In this embodiment, the local data is, for example, an inspection image of a factory-manufactured product. The local label is, for example, if the local data is an inspection image, a category classification of the defect associated with the inspection image (e.g., scratch, stain, deformation). A local model is, for example, a neural network, and in the case of classifying inspection images, it is trained to perform a classification task that classifies inspection images into good and defective products. Note that the task of the local model is not limited to classification tasks, but can be any task such as object detection, semantic segmentation, motion recognition, anomaly detection, suspicious person detection, regression, prediction, etc. Also, the local data is not limited to images, but can be time-series data such as voice, machine sounds, ambient sounds, acceleration data, instrument data, etc. Any data that can be handled by machine learning is acceptable.

[0013] The local decision unit 102 acquires pre-local learning information and determines the federated local learning conditions based on the pre-local learning information. The federated local learning conditions are the conditions for training a local model using local data when using a federated learning method.

[0014] The local learning unit 103 updates the local model based on the federated local learning conditions. Furthermore, if pre-training is required, the local learning unit 103 updates the local model by training it using local data based on the pre-local learning conditions. This allows for obtaining pre-local learning results as the model's training result, and generates pre-local learning information that includes the pre-local learning conditions and pre-local learning results.

[0015] The local communication unit 104 transmits local model parameters and pre-local training information related to the updated local model to the server 11. The local model parameters are the neural network parameters (such as weight coefficients and biases) that are shared with the global model. The local communication unit 104 also receives information about the global model from the server 11. This information about the global model includes, for example, the parameters of the global model.

[0016] Server 11 includes a global storage unit 111, a global determination unit 112, a global update unit 113, and a global communication unit 114.

[0017] The global storage unit 111 stores the global model. The global model is, for example, a neural network. The global decision unit 112 determines global learning conditions using pre-local learning information received from multiple local devices 10.

[0018] The global update unit 113 determines the integration parameters based on the global learning conditions and local model parameters, and updates the global model. The integration parameters are parameters that represent the aggregation ratio of the local model parameters received from each local device 10. The global communication unit 114 receives local model parameters and pre-local training information from multiple local devices 10. The global communication unit 114 transmits information about the updated global model to each local device 10.

[0019] Examples of local and global models include convolutional neural networks (CNNs), multilayer perceptrons (MLPs), recurrent neural networks (RNNs), Transformers, and BERT (Bidirectional Encoder Representations from Transformers). However, neural networks with other common machine learning architectures may also be used as local and global models. Furthermore, this approach is not limited to neural networks; it is applicable to all machine learning models to which associative learning can be applied. For example, models such as SVMs and Random Forests may also be used.

[0020] Furthermore, the parameters included in the pre-local training information are adjusted as needed depending on the type of machine learning model. Specifically, for SVM, the penalty coefficient and tolerance are included in the pre-local training information, while for Random Forest, the number of trees and maximum depth are included.

[0021] Next, the learning process of the learning system 1 according to this embodiment will be described with reference to the sequence diagram in Figure 2. Unless otherwise specified, each of the multiple local devices 10 will execute the process according to the sequence diagram. In this embodiment, it is assumed that pre-local learning information has already been obtained, but the model may be pre-trained according to the pre-local learning conditions and pre-local learning information may be obtained at the stage of executing the learning process of the learning system 1 according to this embodiment.

[0022] In step SA1, the local communication unit 104 of the local device 10 sends pre-local learning information, which associates the pre-local learning conditions with the pre-local learning results, to the server 11.

[0023] In step SA2, the global communication unit 114 of server 11 receives pre-local learning information. In step SA3, the global decision unit 112 of server 11 determines global learning conditions based on pre-local learning information. Global learning conditions are learning conditions related to associative learning, such as the architecture structure of the global model, the conditions for updating the global model, and the conditions for integrating local model parameters. For example, when setting the initial values ​​of the global model, suppose the pre-local learning information shows that a high recognition rate was obtained by initializing the weight parameters of the local model with HeNormal. In this case, by similarly initializing the parameters of the global model with HeNormal, it can be expected that a high recognition rate will be achieved in associative learning as well.

[0024] Furthermore, as part of the global model structure, an individualization method may be adopted to take into account the differences in data distribution among the local devices 10. In this case, the global learning conditions should be determined so that the global decision unit 112 updates the global model while performing a transformation according to the individualization method.

[0025] For example, by analyzing the vector norm or matrix singular values ​​related to the parameters of the trained model included in the pre-local training results, it is possible to estimate unnecessary model structures and the required expressive power (capacity) of the local model. Therefore, for example, by designing the number of layers that are not integrated during associative learning and are individualized layers specific to the local device in proportion to the required expressive power of the local model, associative learning can be performed that provides the optimal model structure (scale) for each of the 10 local devices. Furthermore, it is more beneficial if the pre-local training conditions are determined according to a method suitable for structural analysis (pruning) of the local model.

[0026] Furthermore, there is a proportional relationship between the difficulty of the task and the optimal size of the neural network (e.g., number of parameters, number of channels, number of layers). In other words, if the task is difficult, it is desirable to increase the size of the neural network. Therefore, by designing the number of individualization layers in proportion to the performance (such as recognition rate) obtained from the pre-local training results, associative learning can be performed while providing the optimal model structure (size) for each of the 10 local devices.

[0027] If the task difficulty differs for each of the 10 local devices, associative learning may prioritize parameter updates for easier tasks, failing to adequately reflect the learning results of each local device. In such cases, for example, by taking a weighted average of the parameters of each local model and integrating them, the weight coefficients used when updating the global model can be set to values ​​inversely proportional to the performance of the pre-trained local results (test recognition rate) or metrics that quantify task difficulty (e.g., Shannon information, V-usable information). This allows for an adequate reflection of the learning results of each local device.

[0028] In step SA4, the global communication unit 114 of the server 11 transmits a global model to each local device 10. The global model transmitted here is, for example, a set of neural network parameters shared by the local devices 10.

[0029] In step SA5, the local communication unit 104 of the local device 10 receives the global model from the server 11. In step SA6, the local decision unit 102 of the local device 10 determines the federated local learning conditions based on the pre-local learning information. For example, model parameters that are not shared with the server 11, such as the individualization layer mentioned above, can be initialized using the same initialization method as the pre-local learning conditions, or initialized using the model parameters of the trained model, which are the result of pre-training, thereby reflecting the insights gained during pre-training.

[0030] Furthermore, generally, the smoothness of the loss relative to the model parameters (Loss Landscape) changes depending on the combination of values ​​such as the learning rate, regularization strength, batch size, and data augmentation method. Therefore, it is necessary to set these appropriately according to the environment, such as the difficulty of the task. In this embodiment, for example, the federated local learning conditions can be determined to be the same as, or proportional to, the pre-local learning conditions.

[0031] Furthermore, the regularization strength and the degree of data augmentation are generally set to be strong if overfitting is to be avoided, and weak otherwise; these settings are task-dependent. It is also known that the appropriate optimization function varies depending on the task. For example, SGD is suitable for image classification tasks, while Adam is suitable for generative tasks such as GANs. Moreover, even with the same optimizer, the optimal tuning parameters (momentum, epsilon, etc.) differ. Therefore, by calculating the federated local learning conditions based on prior local learning information, it is possible to efficiently select from a vast number of tuning parameter combinations.

[0032] Furthermore, the number of iterations for updating the local model during training, which is included in the federated local training conditions, may be determined based on the results of prior local training. While increasing the number of training iterations reduces computational costs, there is a trade-off: when the global model on server 11 is updated, the update range of each local model becomes larger, making efficient integration processing difficult. Therefore, the local determination unit 102 of local device 10 sets the number of iterations inversely proportional to, for example, the learning curve of the prior local training results, in this case the rate of change of loss and recognition rate. This allows for stabilizing the update of the global model by reducing the number of iterations at the training timing of local devices with fast training progress, and reducing computational costs by increasing the number of iterations at the training timing of local devices with slow training progress.

[0033] In step SA7, the local learning unit 103 of the local device 10 updates the local model by causing the local model to be learned based on the determined collaborative local learning conditions. Here, K (1 ≤ K ≤ N) devices are selected from all the local devices 10 to perform the learning. When K = N, while there is an advantage that the update information of the local models of all the local devices 10 can be considered when updating the global model of the server 11, it should be noted that the communication cost and the calculation cost increase. Since K can often maintain the performance even at about 10% of N, K may be set to a value smaller than N.

[0034] Specifically, let the input image input to the local model be x → ij (i = 1, 2, 3,..., j = 1,..., N i ) Here, the superscript arrow indicates that the data to which the arrow is attached is tensor data. i is the serial number for identifying the local device 10, j is the serial number of the training data, and N i represents the number of training data sampled by the i-th local device 10, which is a natural number of 2 or more. Also, the input image x → ij is a set of pixels with a width W and a height H, and is two-dimensional tensor data.

[0035] Let the target label for the input image x → ij be represented as t → ij . The target label t → ij is an M-dimensional vector in which the corresponding element is 1 and the other elements are zero. M is the number of classification types, which is a natural number of 2 or more. For example, if the input image x → ij is a product image and has a defect, it can be represented as (1, 0) T and if there is no defect, it can be represented as (0, 1) T . Here, the superscript T represents a column vector.

[0036] Let the input to the local model be the input image x →ij , the output of the local model is y → ij Therefore, it can be expressed by equation (1). y → ij =f(x → ij )···(1) Here, f() represents the neural network function relating to the local model.

[0037] Also, the learning error L ij This is expressed by equation (2). L ij =-t → ij T ln(y → ij )···(2) Here, the learning error L ij This is calculated using cross-entropy. In each local device 10, the local learning unit 103 calculates the average of the learning errors of each of the multiple input images related to a minibatch as the loss, and updates the parameters of the neural network for the local model using backpropagation and stochastic gradient descent to minimize this loss.

[0038] As mentioned above, when updating local models, individualization techniques for each of the 10 local devices, such as meta-learning and distillation, may be employed. For example, the input layer of each local model may be set as a layer with parameters unique to each local model, or part of the intermediate layer may be set as a layer with parameters unique to each local model. Also, if each local model includes a normalization layer, the normalization layer may be set as a layer with parameters unique to the local model. In this way, instead of directly copying the received global model to the local model, the global model may be transformed according to the personalization technique and the local model may be updated.

[0039] In step SA8, the local learning unit 103 of the local device 10 determines whether the local model update is complete. For example, the update can be determined to be complete when the update has been completed for the number of iterations set based on the federated local learning conditions. Alternatively, the update may be determined to be complete when the absolute value or sum of the absolute values ​​of the parameter update amounts reaches a certain value. The determination of whether the update is complete is not limited to the above example, but may also be made using termination conditions commonly adopted in machine learning. If the local model update is complete, the process proceeds to step SA9; otherwise, the process returns to step SA7 and repeats.

[0040] In step SA9, the local communication unit 104 of the local device 10 sends local model parameters related to the updated local model to the server 11. The local model parameters may be, for example, the updated parameters, or the amount of change due to the update, for example, the difference between the parameters before the update and the parameters after the update. The local communication unit 104 may also compress the data related to the parameters to be sent to the server 11 before sending it. The data compression process may be lossless or lossy. By compressing the data before sending it, communication volume and communication bandwidth can be saved. The data may also be encrypted before sending it, which can improve data confidentiality.

[0041] In step SA10, the global communication unit 114 of the server 11 receives local model parameters from each local device 10. In step SA11, the global update unit 113 of the server 11 updates the global model based on the local model parameters and global learning conditions. Updating the global model can be done by integrating the local model parameters of each local device 10, which can be expressed, for example, by equation (3). Θ g =Σ i∈S (a i xΘ i )··· (3) Θ gΘ is a model parameter of the global model. S is the sequential number of the K devices that have been updated. i These are the model parameters excluding the individualization layer of the local model. i This is an integrated parameter that represents the aggregation ratio of local model parameters, or in other words, a weight coefficient for each local model. i This is determined in step SA5. The global model update method can be any general update method used in associative learning, as long as it adheres to the global learning conditions.

[0042] In step SA12, the global update unit 113 of the server 11 determines whether to continue federated learning. Whether to continue federated learning can be determined by, for example, when the performance of the local models of each local device 10, such as recognition rate, accuracy, precision, and recall, reaches the target value, when the global model has been updated a predetermined number of times, or when the update range of the global model has converged to below a threshold. In such cases, it can be determined that federated learning has ended and not to continue. If federated learning is not to be continued, it ends; if it is to continue federated learning, the process proceeds to step SA13.

[0043] In step SA13, the global communication unit 114 of the server 11 transmits information about the global model to each local device 10. The information about the global model includes, for example, the global model itself, the updated global model parameters, and at least one of the amounts of change due to the update.

[0044] In step SA14, the local communication unit 104 of the local device 10 receives information about the global model from the server 11. The learning system 1 then simply repeats the processes from step SA4 to step SA14 until federated learning is complete.

[0045] The number of global model updates (also called the number of global iterations) must be set appropriately according to the expressive power of the global model or the task difficulty level of each local device (10). Too few updates may result in underperforming performance, while too many updates may generate redundant computation and communication costs, or lead to performance degradation due to overfitting. Therefore, for example, the number of global model updates can be set to a value proportional to the maximum, median, and mean number of training epochs included in the pre-local training conditions of each local device 10. This allows for setting an appropriate number of global model updates.

[0046] Alternatively, the local devices 10 participating in federative learning may be grouped into multiple groups, and federative learning may be performed for each group. For example, rather than applying federated learning to multiple local devices 10 with extremely different local data distributions, task difficulty levels, and optimal conditions, federated learning can be performed more efficiently by grouping the local devices participating in federated learning and applying federated learning to each group. For instance, the global decision unit 112 of the server 11 can extract local devices 10 with similar conditions based on pre-local learning conditions (e.g., learning rate and optimizer) and pre-local learning results (recognition rate, loss). In this case, the local devices 10 with similar conditions can be grouped together, and federated learning can be applied to each group.

[0047] Furthermore, the global decision unit 112 of server 11 may refer to pre-local learning information and, if there is a local device 10 with a small number of learning epochs (number of iterations), set the probability of executing the local model update process in step SA7 during federated learning to a lower value. This reduces the communication cost and learning time between the local device 10 and the entire federated learning process, while achieving a high recognition rate while updating the local device 10 with a small number of epochs.

[0048] In the above embodiment, it is assumed that all local devices 10 have the same recognition category (e.g., classification of objects) and that learning is performed using local data of the same image size in the classification task. However, the recognition categories or data sizes may differ among the local devices 10. For example, if the recognition categories are different, individualized output layers can be prepared according to the number of output channels. This allows learning to be performed according to the number of recognition categories while utilizing image knowledge. Also, if the image sizes differ as data size, the width (number of channels) and depth of the neural network can be individualized. This allows learning to be performed according to the receptive field of the image.

[0049] Furthermore, in the above-described embodiment, it was assumed that federated local learning conditions and global learning conditions were calculated based on pre-local learning information at the stage of starting federated learning, and that the same federated local learning conditions and global learning conditions were used during the execution of federated learning, but this is not limited to this. For example, the federated local learning conditions and global learning conditions may be modified as appropriate during the learning process of federated learning, such as when the global model update is completed, based on the pre-local learning information and the learning progress of the federated learning in progress. Specifically, for example, the aggregation ratio (integration parameter) can be set to have a larger weight for local devices 10 that deviate greatly from the pre-local learning results, thereby preventing the occurrence of local devices 10 whose learning is delayed.

[0050] Furthermore, in the above embodiment, it is assumed that the local model of local device 10 and the global model of server 11 are neural networks with basically the same structure. However, the local models of multiple local devices 10 may each be scalable neural networks that share some parameters with the neural network of the global model. A scalable neural network is a neural network that allows the model size, such as the number of convolutional layers in the network model, to be adjusted according to the required computational load or performance. For example, if the local models differ in each local device 10, the model structure, model size, number of parameters such as weight coefficients and biases will differ. Server 11 can update the parameters of the global model and send a portion of the global model to each local device 10 according to the scale of each local model.

[0051] Here, an example of the hardware configuration of the local device 10 and server 11 according to the above embodiment is shown in the block diagram of Figure 3. The local device 10 and the server 11 each include a CPU (Central Processing Unit) 31, RAM (Random Access Memory) 32, ROM (Read Only Memory) 33, storage 34, display device 35, input device 36, and communication device 37, and are connected by buses.

[0052] The CPU 31 is a processor that performs arithmetic and control processing according to a program. The CPU 31 uses a predetermined area of ​​the RAM 32 as a working area and, in cooperation with programs stored in the ROM 33 and storage 34, performs the processing of each part of the local device 10 and server 11 as described above.

[0053] RAM32 is a type of memory such as SDRAM (Synchronous Dynamic Random Access Memory). RAM32 functions as a workspace for the CPU31. ROM33 is a memory that stores programs and various information in a non-rewritable format.

[0054] The storage device 34 is a device that writes and reads data from magnetic recording media such as HDDs (Hard Disk Drives), semiconductor storage media such as flash memory, or optically recordable storage media. The storage device 34 writes and reads data from the storage media in response to control from the CPU 31.

[0055] The display device 35 is a display device such as an LCD (Liquid Crystal Display). The display device 35 displays various information based on display signals from the CPU 31. The input device 36 is an input device such as a mouse and a keyboard. The input device 36 receives information input by the user as an instruction signal and outputs the instruction signal to the CPU 31. The communication device 37 communicates with external devices via a network in response to control from the CPU 31.

[0056] The instructions shown in the processing procedure described in the above-described embodiment can be executed based on a software program. A general-purpose computer system can store this program in advance and, by reading this program, can obtain effects similar to those of the control operation of the learning system (local device and server) described above. The instructions described in the above-described embodiment are recorded as a program that can be executed by a computer on a magnetic disk (flexible disk, hard disk, etc.), optical disk (CD-ROM, CD-R, CD-RW, DVD-ROM, DVD±R, DVD±RW, Blu-ray® Disc, etc.), semiconductor memory, or similar recording medium. Any storage format is acceptable as long as it is a recording medium that can be read by a computer or embedded system. The computer can read the program from this recording medium and, based on this program, have the CPU execute the instructions described in the program, thereby achieving operations similar to the control of the learning system (local device and server) in the above-described embodiment. Of course, when the computer acquires or reads the program, it may do so via a network. Furthermore, an operating system (OS) running on a computer, a database management software, a network, or other middleware (MW) operating on a computer, based on instructions from a program installed on a computer or embedded system from a recording medium, may execute some of the processes necessary to realize this embodiment. Furthermore, the recording medium in this embodiment is not limited to a medium independent of the computer or embedded system, but also includes a recording medium that stores or temporarily stores a program that has been downloaded via a LAN, the Internet, or the like. Furthermore, the recording medium is not limited to one; even when the processing in this embodiment is performed from multiple media, these are also included as recording media in this embodiment, and the configuration of the media may be any configuration.

[0057] In this embodiment, the computer or embedded system is used to execute each process in this embodiment based on a program stored on a recording medium, and may be configured as any of the following: a single device such as a personal computer or microcontroller, or a system in which multiple devices are connected via a network. Furthermore, the term "computer" in this embodiment is not limited to personal computers, but also includes arithmetic processing units, microcontrollers, and the like included in information processing equipment, and refers collectively to any equipment or device capable of realizing the functions of this embodiment through a program.

[0058] According to the embodiment described above, the federated local learning conditions and global learning conditions in federated learning are determined using pre-local learning information, which includes the pre-training conditions and learning results obtained when pre-training on a local device. This makes it possible to appropriately set many federated learning conditions that take into account the local data of each local device, for example, the properties and difficulty of the local data.

[0059] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims and their equivalents. [Explanation of symbols]

[0060] Learning system…1, 10, 10A, 10B…Local devices, 11…Server, 101…Local storage unit, 102…Local decision unit, 103…Local learning unit, 104…Local communication unit, 111…Global storage unit, 112…Global decision unit, 113…Global update unit, 114…Global communication unit, 31…CPU, 32…RAM, 33…ROM, 34…Storage, 35…Display device, 36…Input device, 37…Communication device

Claims

1. A learning system including multiple local devices and a server, Each of the multiple local devices is: The system comprises a local determination unit that determines federated local learning conditions, which indicate the learning conditions in federated learning of local models, based on pre-local learning information including pre-local learning conditions and pre-local learning results when a model is trained in advance using local data. The aforementioned server, The system includes a global decision unit that determines the global learning conditions of the global model based on the aforementioned pre-local learning information. Learning system.

2. The aforementioned server, The system further comprises a global update unit that updates the global model by integrating the parameters of the local model received from each of the multiple local devices based on the global learning conditions, Each of the multiple local devices is: The learning system according to claim 1, further comprising a local learning unit that updates the local model based on parameters relating to the updated global model.

3. The learning system according to claim 1, wherein the pre-local learning conditions include information relating to the local model, including at least one of the selection of learning rate, regularization, mini-batch size, initialization method, optimizer, and architectural structure.

4. The learning system according to claim 1, wherein the pre-local learning results include information relating to at least one of the recognition rate, loss, learning curve, model weights, and pruning results when the local model is trained using the pre-local learning conditions.

5. The learning system according to claim 1, wherein the global learning conditions include information from the individualization layer of the local model based on differences in data distribution between the local devices.

6. The global determination unit groups local devices with similar data distributions or learning statuses based on the pre-local learning information, and determines the information regarding the grouped local devices as the global learning conditions. The learning system according to claim 1, wherein the server performs the federated learning for each of the grouped local devices based on the global learning conditions.

7. The aforementioned pre-local training information includes the number of training epochs, The learning system according to claim 1, wherein the global decision unit sets the number of updates of the global model based on the number of learning epochs.

8. The learning system according to claim 1, wherein the local determination unit modifies the federated local learning conditions based on the prior local learning information and the learning progress of the federated learning.

9. The learning system according to claim 1, wherein the global determination unit modifies the global learning conditions based on the pre-local learning information and the learning progress of the federated learning.

10. A learning method for a learning system including multiple local devices and a server, Based on pre-local training information, including pre-local training conditions and pre-local training results when a model is trained in advance using local data, we determine the federated local training conditions that indicate the training conditions in federated training of the local model. A learning method that determines the global learning conditions of a global model based on the aforementioned pre-local learning information.

11. A learning program in a learning system that includes multiple local devices and a server, Computers, A local decision means for determining federated local learning conditions that indicate the learning conditions in federated learning of local models, based on pre-local learning information including pre-local learning conditions and pre-local learning results when a model is trained in advance using local data, A learning program that functions as a global decision-making tool to determine the global learning conditions of a global model based on the aforementioned pre-local learning information.

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