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50 results about "Time series similarity" patented technology

A model for identifying similar time series has been developed. Two time series are considered similar if they have enough non overlapping time ordered sub- sequences that are similar. The two subsequences are considered to be similar if one is enclosed within an envelope of a user defined width around another.

Embedded index based hydrological time series similarity searching method

The present invention discloses an embedded index based hydrological time series similarity searching method. The method is carried out by the following steps: calculating corresponding embedded index vectors of each position in an original time series in an off-line preparation stage, wherein in the off-line preparation stage, the hydrological time series flood peak segmentation, serial clustering, initial reference sequence set generation, reference set training and time series embedded index calculation are realized; and calculating the index vectors by using a query sequence and a reference set sequence in an on-line searching stage, performing searching in an embedded index Euclidean vector space of the original series to find a relatively similar point as a candidate point set, refining candidate points, and then performing original DTW (dynamic time warping) measurement to find a final similar sequence. According to the embedded index based hydrological time series similarity searching method, the similarity searching is mapped to the Euclidean vector space to perform searching, thereby greatly improving the search efficiency.
Owner:HOHAI UNIV

Time-series similarity measurement method based on segmented statistical approximate representation

The invention discloses a time-series similarity measurement method based on segmented statistical approximate representation. The method comprises the steps of feature extraction and dynamic pattern matching. First, a time series is segmented into sub series, the various statistical features of the sub series are sequentially extracted, and local pattern feature vectors are constructed; then the distance between the local pattern feature vectors is calculated by the weighted Euclidean distance, local pattern matching is achieved, the matched local pattern is used as the sub program of a dynamic programming algorithm, and global pattern matching is achieved. The method is superior to other measurement methods by a large degree on the aspects of measurement precision and calculation efficiency, and plays an important role in daily activities and industrial production of people, for example, financial transactions, traffic control, air quality and temperature monitoring, industrial flow monitoring, medical diagnosis and the like. Large scale sampling data or high-speed dynamic data flow is subjected to similarity-based search, classification, clustering, prediction, abnormal detection, on-line pattern recognition and the like.
Owner:ZHEJIANG UNIV

Financial time series similarity query method based on K-chart expression

The invention discloses a financial time series similarity query method based on K-chart expression. The method comprises the following steps of feature extraction, index construction and query processing. The method comprises the following concrete steps of firstly, extracting basic mode and classic mode features for a financial time series based on K-chart expression, and respectively translating the basic mode and classic mode features into a basic string and a classic string; secondly, respectively constructing reverse indexes on the basic string and the classic string; for each query sequence, after the basic mode and classic mode features are extracted through the same way, respectively querying the two constructed reverse indexes to acquire two candidate sets, and then carrying out intersection operation to obtain a final candidate set; obtaining a final query result through follow-up processing. The financial time series similarity query method based on K-chart expression can effectively realize nearest neighbor query, has higher measurement precision and query efficiency, has favorable extensibility for time series length, nearest neighbor query scale and data set scale, and can play a significant role in the widened electronic finance trade market.
Owner:ZHEJIANG UNIV

Vegetation change occurrence time detection method based on time series similarity

The invention relates to a vegetation change occurrence time detection method based on time series similarity, comprising: first, establishing multi-year time-space continuous vegetation index time series data of a research area, calculating JM distance between vegetation index time series curves of each past year and the initial year pixel by pixel, year by year, and generating a time series curve for the JM distance of each past year and the original year; fitting the time series curve for the JM distance of each past pear and the original year by using a logistic model, and acquiring time parameter from logistic model parameters so as to automatically extract vegetation change time. In the method, the JM distances of vegetation index time series curves between the past years and the initial year are used to indicate time series similarity, and vegetation change time is acquired from change law of yearly time series similarity. The method is effective in detecting changes of time series curves in terms of amplitude, frequency and the like, the complex step of decomposing original spectral index time series data is avoided, and the problem that it is difficult to extract indexes directly from original spectral index time series data to provide comprehensive characterization of vegetation changes is solved.
Owner:FUZHOU UNIV

Trend segmentation similarity-based airport noise monitoring point exception identification method

The invention discloses a trend segmentation similarity-based airport noise monitoring point exception identification method and belongs to the technical field of airport noise monitoring point exception analysis. The method comprises the steps of firstly obtaining noise monitoring data of monitoring points around an airport by utilizing a monitoring device; secondly preprocessing the monitoring data and creating a standard noise time series data set; thirdly performing dimension reduction expression on noise time series of the monitoring points by using a trend segmentation-based time series expression method; fourthly by utilizing a trend segmentation-based similarity measurement method, measuring noise time series similarity between the monitoring points, and establishing a similarity matrix; fifthly finding out first k monitoring points with relatively high similarity with each monitoring point, and creating a similar monitoring point set; and finally measuring the similarity between new noise time series of the monitoring points and new noise time series of associated monitoring points, and if the similarity is remarkably changed, determining that the monitoring points are exceptional. According to the method, the monitoring point exception can be accurately identified, so that the timeliness and validity of airport noise monitoring point maintenance are effectively improved.
Owner:NANJING UNIV OF AERONAUTICS & ASTRONAUTICS

Time-series similarity measurement method under data missing

The invention discloses a time-series similarity measurement method capable of adapting to missing data. According to the method, data pairs are extracted from two original time series in pairs and are divided into five types according to data missing conditions, and first-order similarity intervals are calculated respectively; intervals are extracted from the first-order similarity intervals in pairs, second-order similarity is figured out, and second-order similarity vector quantities are obtained; at last, the second-order similarity vector quantities are averaged to obtain final similarity of the two time series. The method can adapt to multiple scenes, is simple and does not have any requirement for data integrity.
Owner:ZHEJIANG UNIV

Oil immersed transformer state evaluation method

The invention discloses an oil immersed transformer state evaluation method. The method includes constructing to-be-measured data to characterize the characteristics of an oil immersed transformer byusing the oil and gas data of the oil immersed transformer; obtaining fault oil immersed transformer data, and dividing six fault data clusters according to fault types; calculating the relative proximity of the to-be-measured data and the fault data clusters according to big data clustering thought; dividing an equipment state into a health state, a latent fault state or a fault state; judging the fault types of fault equipment on this basis, and calculating the health scores of the health equipment based on the fault type associating with weight; and obtaining the predicting fault development time of latent fault equipment through a time series similarity analysis method. Thus, the time inverting into the fault state can be accurately predicted, the hidden risks of the equipment can be found before fault occurs, and early detection and solution of equipment hidden danger can be realized.
Owner:STATE GRID JIANGXI ELECTRIC POWER CO LTD RES INST +1

Harmonic source tracing method based on algorithm with dynamic planning time series similarity

The invention provides a harmonic source tracing method based on an algorithm with dynamic planning time series similarity, comprising: obtaining, from an electric energy quality monitoring system, harmonic voltage monitoring data in a period of time collected by an electric energy quality monitoring terminal installed on a certain bus; obtaining, from a power consumption information collecting system, power consumption active power data in the time period of all users supplied by the bus; processing the harmonic voltage monitoring data and the power consumption active power data by using a data standardization method; and solving the correlation between the power consumption active power series data of each user and the harmonic voltage series data of the common connection points by usingan algorithm that solves the time series data similarity based on the dynamic planning principle, and carrying out the harmonic source tracing. The method provided by the invention fully mines the value of smart meter data deployed on a large scale, and infers possible users that cause harmonic problems by data correlation analysis results of the power consumption condition and the harmonic condition of the users, thereby providing a basis for accurate harmonic responsibility division, future quality-based pricing, and precise control.
Owner:FUZHOU UNIV

Principal-component analysis-based construction method of multivariate hydrological time series matching model

The invention discloses a principal-component analysis-based construction method of a multivariate hydrological time series matching model. Combined-model construction of multivariate hydrological time series similarity matching is carried out on the basis of principal-component analysis (PCA) and dynamic-time-warping (DTW) methods. The construction method includes: firstly, carrying out isomorphic processing on original data, wherein a Z-score standardization method is adopted; then carrying out piecewise aggregate approximation (PAA) processing on the processed data, and carrying out PCA processing on the data after PAA processing, wherein dimension reduction of the data in both a time dimension and a variable dimension is realized after the two times of processing; and finally, using aweighted DTW method for similarity matching, and obtaining a time series, which is most similar to a given time series, by matching. The construction method improves accuracy and time efficiency of similarity matching, provides services for hydrological forecasting and hydrological data analysis, and has higher application values for needs of water conservancy informatization and water conservancymodernization.
Owner:HOHAI UNIV

A Harmonic Traceability Method Based on Dynamic Programming Time Series Similarity Algorithm

ActiveCN113435490BComprehensive and accurate monitoring and judgmentThe judgment method is simple and effectiveSpectral/fourier analysisCharacter and pattern recognitionTime segmentElectric consumption
The present invention belongs to the field of electric power technology, in particular, a harmonic source tracing method based on a dynamic programming time series similarity algorithm. Aiming at the problem of poor accuracy, the following scheme is proposed, including the following steps: S1: extract a certain time in a certain day and a method in the system All harmonic data at this time every day; S2: Extract the same time period of the day and all unit time power consumption in the system at this time every day; S3: Process all harmonic data and power consumption per unit time at a certain time on a certain day to form Change curve; S4: weighted average of all harmonic data and power consumption per unit time at a certain time each day to form a change curve; S5: respectively subtract the data of a certain day from the weighted average of harmonic data and power consumption per unit time , get the absolute value and then calculate the average value; S6: use the sequence similarity algorithm to calculate and solve, and trace the source of harmonics according to the calculated value. The present invention monitors and judges the harmonic data more comprehensively and accurately, and the judgment method is simple and effective.
Owner:ELECTRIC POWER RESEARCH INSTITUTE OF STATE GRID NINGXIA ELECTRIC POWER COMPANY +1

Vegetation Change Occurrence Time Detection Method Based on Temporal Similarity

The invention relates to a vegetation change occurrence time detection method based on time series similarity, comprising: first, establishing multi-year time-space continuous vegetation index time series data of a research area, calculating JM distance between vegetation index time series curves of each past year and the initial year pixel by pixel, year by year, and generating a time series curve for the JM distance of each past year and the original year; fitting the time series curve for the JM distance of each past pear and the original year by using a logistic model, and acquiring time parameter from logistic model parameters so as to automatically extract vegetation change time. In the method, the JM distances of vegetation index time series curves between the past years and the initial year are used to indicate time series similarity, and vegetation change time is acquired from change law of yearly time series similarity. The method is effective in detecting changes of time series curves in terms of amplitude, frequency and the like, the complex step of decomposing original spectral index time series data is avoided, and the problem that it is difficult to extract indexes directly from original spectral index time series data to provide comprehensive characterization of vegetation changes is solved.
Owner:FUZHOU UNIV
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