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48 results about "Exponentially weighted moving average" patented technology

An exponential moving average (EMA) is a type of moving average (MA) that places a greater weight and significance on the most recent data points. The exponential moving average is also referred to as the exponentially weighted moving average.

Content classification based category popularity cache replacement method in oriented content-centric networking

The invention relates to a content classification based category popularity cache replacement method in an oriented content-centric networking. The content classification based category popularity cache replacement method comprises the following steps: firstly determining whether a remaining cache space of a node can accommodate new data content or not; caching the new data content if the cache space is enough; calculating the popularity of all content categories in standard computing nodes according to an exponentially weighted moving average method, and selecting the content category with the smallest popularity; removing a content item with the fewest request times in predefined time in the content category with the smallest popularity out of a node cache; extracting name character string characteristics of the new data content and classifying; storing the newly arrived data content item into corresponding content category in the node, and updating a category heat table and a log. The cache of nodes in CCN (content-centric networking) can be better managed according to the content name category, so that the content can be found and replaced from the name of the content in the communication process in the networking, the diversity of the content in the node cache is balanced, and the efficiency of cache replacement is improved.
Owner:HARBIN ENG UNIV

Cloud computing system load predicting method capable of automatically adjusting parameters

The invention discloses a cloud computing system load predicting method capable of automatically adjusting parameters, which comprises the following steps: at the moment t, computing the actual load O(t) of a system at the moment t through system call; executing short-term prediction; computing alpha (t) and E(t) by utilizing the O(t) value and historical data; executing long-term prediction; computing alpha T(t) and ET(t) by utilizing the O(t) and the historical data; combining the short-term prediction and the long-term prediction; when t is less than T, outputting the O(t) and switching to the next step; otherwise, taking the maximum value or average value of E(t-1) and ET(t-T) as the output at the moment t; and updating the historical data, waiting the moment t+1 and switching to the first step. In the invention, the alpha (t) and the alpha T(t) are computed in real time through error functions, thereby enhancing the prediction accuracy of classic EWMA (Exponentially Weighted Moving Average); the requirement that a prediction value is slightly larger than an actual value can be met by expanding the alpha (t) and the alpha T(t) to an interval (-1, 1); and the responsiveness of the prediction to the load periodicity of a cloud computing platform is enhanced by introducing a long-term prediction module.
Owner:PEKING UNIV

Magcard decoding method

The invention discloses a magcard decoding method comprising the following steps: S1. converting a sampled analog waveform to an initial digital waveform by adopting an extremum method and correcting the pulse width of the initial digital waveform by adopting a curve fitting method; S2. taking the pulse width of purported leading zero bits of a magcard as an initial reference pulse width, distinguishing a first pulse width of the corrected digital waveform by utilizing the initial reference pulse width, obtaining a second reference pulse width on the basis of the initial reference pulse width according to an EWMA (exponentially weighted moving average) formula, distinguishing a second pulse width of the corrected digital waveform by taking the second reference pulse width as a reference, and repeatedly executing the process of adjusting the reference pulse width and distinguishing the pulse width of the corrected digital waveform according to the corresponding reference pulse width until all of the pulse widths of the corrected digital waveform are distinguished; S3. converting the corrected digital waveform to a corresponding 0/1 bit sequence according to the distinguished result of the step S2; and S4. decoding the bit sequence according to magcard standards.
Owner:FUJIAN LANDI COMML EQUIP CO LTD

Monitoring method of state of gearbox bearing of wind turbine generator system

The invention discloses a monitoring method of the state of a gearbox bearing of a wind turbine generator system. The method comprises the steps of selecting variables by adopting a ReliefF feature selection algorithm, establishing an improved noise reduction self-encoding network to establish a relation model between the temperature of the gearbox bearing and influence variables thereof, reconstructing modeling variables in a monitoring stage by using the model, and predicting the temperature of the gearbox bearing; performing calculation according to a modeling variable reconstruction errorof normal operation data of the wind turbine generator system to obtain an exponentially weighted moving average control chart threshold; obtaining the fact that the unit operates normally if an EWMAcontrol chart statistic of the monitored unit is less than a threshold; and giving an alarm that the temperature of the gearbox bearing is abnormal if the temperature exceeds the threshold. The methodis used for analyzing the temperature data of the gearbox bearing, the goals of artificial intelligence monitoring and fault early warning of the temperature of the gearbox bearing of the wind turbine generator system are efficiently and accurately achieved, and the example analysis verifies the practicability and the universality of the method.
Owner:HUANENG POWER INT INC +2

Bearing performance degradation state detection method and system

The invention discloses a bearing performance degradation state detection method and system. The method comprises the steps: S1, collecting vibration signals in the full-life service process of a bearing; S2, constructing a high-dimensional degradation trend feature set, and performing smoothing processing by using exponentially weighted moving average; S3, designing a feature sensitivity evaluation criterion, and screening out a bearing performance degradation state sensitive feature set; and S4, fusing the sensitive feature set by using a consistent manifold approximation algorithm, and further smoothing the fusion index by using exponential weighted moving average to form a bearing performance degradation state curve. According to the method, noise in characterization indexes can be removed, and fluctuation in the performance degradation process of the bearing is slowed down; monotonicity and correlation in the bearing performance degradation process are integrated in the characterization index screening criterion, and effective characterization indexes can be selected more reasonably; and consistent manifold approximation algorithm is used for fusing selected effective indexes, the global structure and the local structure of data can be considered, and the defects of a traditional data fusion method are overcome.
Owner:SUZHOU UNIV

Energy acquisition type wireless sensor network monitoring frequency maximization method

The invention discloses an energy acquisition type wireless sensor network monitoring frequency maximization method, comprising the following steps: setting up a virtual source node, establishing a connection relationship between the virtual source node and a monitored target node, predicting the energy acquired by monitoring nodes according to an exponentially weighted moving average process, and setting link weights between monitoring network nodes based on energy acquisition; performing monitoring network topology decomposition, performing topology decomposition by adopting a node splitting operation, and establishing a decomposed monitoring network; sequentially calculating maximum energy flow paths from the virtual source node to receiving nodes according to the decomposed monitoring network, performing reverse operation on each path, and subtracting energy values required for the monitoring of the nodes on the paths; updating the link weights of the monitoring network; repeating the above calculations until no maximum energy flow exists; and calculating the number of maximum energy paths to obtain the target monitoring frequency. According to the method disclosed by the invention, the network monitoring frequency and energy utilization performance can be improved, the maximization of the monitoring frequency can be achieved, and the throughput of the monitoring network also can be effectively improved.
Owner:NANCHANG INST OF TECH

Method for detecting tiny faults of satellite attitude control system and based on locally linear embedding (LLE)

The invention discloses a method for detecting tiny faults of a satellite attitude control system and based on locally linear embedding (LLE). The method is based on a locally linear embedding method,and comprises the steps that firstly, historical data is enabled to have a zero mean value and a unified variance, then the number of neighborhood points is determined by a dynamic locally linear embedding (DLLE) method, a weight matrix W is reconstructed dynamically, then low-dimensional embedding Y of a sample set is found through the obtained weight matrix W, and two statistics of T<2> and SPEare further acquired; then an exponentially weighted moving average (EWMA) is solved by using an EWMA algorithm, an EWMA statistic range of normal data is used as a threshold value for judging whether to-be-detected data has faults or not, a mapping matrix A is further obtained and used for calculating the statistics of T<2> and SPE of online data, and the corresponding EWMA statistics is calculated; and finally whether the EWMA statistic of the online data is greater than a control limit or not is judged, if the EWMA statistic is greater than the control limit, the system faults are generated, and if not, the system is normal. According to the method for detecting the tiny faults of the satellite attitude control system and based on LLE, deficiencies of an original algorithm are overcome, and the detecting performance of the algorithm towards the tiny faults is improved.
Owner:CHINA XIAN SATELLITE CONTROL CENT

Method and system for detecting working state of aerator

An embodiment of the present invention provides a method and system for detecting the working state of an aerator. The method comprises a step of acquiring a corner point corresponding to a corner point in a target area in each frame and a reference frame according to an optical flow method for each frame in an aerator video to be detected, a step of acquiring an average displacement of the corresponding corner point in the frame and obtaining an exponentially weighted moving average displacement according to the average displacement, a step of inputting the average displacement of the corresponding corner point in the frame and the exponentially weighted moving average displacement into a preset support vector machine to obtain the working state of the aerator in the frame. According to the method and system for detecting the working state of an aerator provided by the embodiment of the present invention, the reference frame is used as a comparison object, the matched corner point isobtained by corner point detection and the optical flow method, the working state of the aerator is detected according to the average displacement of the matched corner point and the exponentially weighted moving average displacement by using the support vector machine, very obvious classification features can be extracted, the possibility of interference is little, and the accuracy of detecting the working state of the aerator can be improved.
Owner:CHINA AGRI UNIV

Offshore wind turbine generator gear system fault diagnosis method based on Park transformation

The invention discloses an offshore wind turbine generator gear system fault diagnosis method based on Park transformation. The method comprises the following steps of: collecting three-phase current parameters of an offshore wind turbine generator stator; preprocessing the three-phase current parameters through park conversion to determine a fault characteristic quantity; supplying the fault characteristic quantity to an auto-encoder in a sample learning mode for sample training; obtaining a hidden layer representation method by the auto-encoder, enabling an encoder to finely adjust the parameters of the whole system according to a training result after training of a plurality of hidden layers to obtain a neural network model with feature extraction and mode recognition functions, and calculating a threshold; and inputting test online data into the trained neural network model to obtain an abnormal score score of a test set, and drawing an exponentially weighted moving average value control chart to judge whether a fan gearbox has a fault or not. The method is better in noise reduction capability, is higher in diagnosis precision, and can meet the precision and real-time requirements of offshore wind power.
Owner:CHINA THREE GORGES CORPORATION

A Blast Furnace Molten Iron Quality Monitoring Method Based on Adaptive Threshold pls

ActiveCN107290962BGuaranteed normal judgmentAccurate judgmentAdaptive controlMoving averageControl limits
The present invention provides a blast-furnace molten iron quality monitoring method based on adaptive threshold PLS. The method comprises: collecting blast furnace operation parameters and molten iron quality variables at the same moment; selecting data in the blast-furnace molten iron normal process as a training set, calculating a mean value and a standard deviation and performing standardization processing; constructing a PLS model; obtaining the new blast furnace operation parameter sample data of the blast-furnace ironmaking process and performing standardization processing; aiming at a test set, employing a Q statistical magnitude and an Hotelling's T<2> statistical magnitude to detect whether the blast-furnace ironmaking process generates anomaly or not, calculating the Q statistical magnitudes and the T<2> statistical magnitudes of the test set samples, and calculating a fixed control limit; and calculating the index weight mobile mean value of each sample statistical magnitude at present in real time so as to determine the T<2> statistical magnitude adaptive threshold and the Q statistical magnitude adaptive threshold at the current moment and complete the fault detection of the test set. The method provided by the invention obviously reduces the fault false alarm rate and ensures the accuracy and the sensitivity of a fault detection result.
Owner:NORTHEASTERN UNIV LIAONING
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