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80 results about "Similarity query" patented technology

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

Multi-dimensional index structure under cloud environment, construction method thereof and similarity query method

The invention discloses a multi-dimensional index structure under a cloud environment, a construction method thereof and a similarity query method. The index structure disclosed by the invention comprises a global index and local indexes which are respectively positioned at all storage nodes, the cloud environment uses an overlay network to organize the storage nodes, and the local indexes are of clustering results obtained by clustering approximate vectors of all vector data in the storage nodes where the local indexes are located; and the global index is of information of clustering centers of all the local indexes, which are distributed to the whole overlay network and addresses of the storage nodes where the clustering centers are located. The index structure disclosed by the invention has the advantages of reducing index storage space, reducing resource consumption, effectively supporting multi-dimensional data index and similarity query under the cloud environment, using the clustering information obtained by clustering all the approximate vectors as the local indexes and improving query efficiency by only performing query on corresponding categories through the information of the clustering centers without scanning all the approximate vectors during the query of the local indexes.
Owner:NANJING UNIV OF POSTS & TELECOMM

Anomaly detection method based on data incremental graphs

The invention discloses an anomaly detection method based on data incremental graphs. The anomaly detection method includes the following steps that detection data in a current monitoring zone of a wireless sensor network are collected and preprocessed, and an event zone is determined; data sets relevant to a current event are acquired, a graph model is utilized to abstractly generalize event data, and the event data are converted into the event data incremental graphs; a graph similarity algorithm based on structure correlation is utilized to search an event mode graph database for event mode graphs similar to the event graphs and judge the type of the current event, wherein the event mode graph database is a set of the event mode graphs; the event mode graphs are the event data incremental graphs and abstract description for types of events; by the adoption of the graph similarity query algorithm based on the structure correlation, the graph similarity query problem is converted into the sequence similarity query problem, and therefore query complexity is effectively reduced. By the adoption of the anomaly detection method based on the data incremental graphs, the event graphs can be acquired based on domain expert knowledge or data analysis and used for detecting complex events, the detection efficiency of the events is improved, and the false alarm rate is reduced.
Owner:SOUTHEAST UNIV

Time sequence similarity measurement method based on self-adaptive piecewise statistical approximation

The invention discloses a time sequence similarity measurement method based on self-adaptive piecewise statistical approximation. The method comprises the following steps of firstly, segmenting a time sequence into subsequences containing complete fluctuation trends based on time sequence coded identification turning points; secondly, extracting various statistical characteristics of each subsequence in sequence so as to configure local pattern character vectors; and lastly, computing a distance between the local pattern character vectors by utilizing a normalized distance so as to realize local pattern matching, and using the local pattern matching as a subprogram of a dynamic programming algorithm so as to realize global pattern matching. The time sequence similarity measurement method is better than the other measurement method in the aspects of measurement precision and computational efficiency to a larger extent, and plays an important role in daily activities and industrial production of people, such as similarity search, classification, clustering, predication, anomaly detection, on-line pattern recognition and the other processing of large-scale sampling data or high-speed dynamic data flow in banking transaction, traffic control, air quality and temperature monitoring, industrial flow monitoring, medical diagnosis and the other application.
Owner:ZHEJIANG UNIV

Privacy-protected encrypted image retrieval method and system

The invention discloses a privacy-protected encrypted image retrieval method and system, and the method comprises the specific implementation steps that an image owner extracts the feature vector of an image, encrypts the image and the feature vector, and uploads the encrypted image and the encrypted feature vector to a cloud server; when a query user searches, a query vector of a query image is extracted and encrypted, and a trap door is generated from the encrypted query vector and a set similarity query threshold and sent to the cloud server; and the cloud server retrieves the encrypted image set according to the query trap door and the index table and returns a retrieval result to the query user, and the query user decrypts the retrieval result to obtain a retrieval result. According to the method and system, based on the chaotic mapping image encryption algorithm, the convolutional neural network model is adopted to extract the image features, the image retrieval efficiency is improved, and finally, the cloud server only returns similar results within the threshold range and does not perform similar sorting, so that the security is further improved. The whole retrieval processis achieved in a ciphertext domain, and safe retrieval of the image is effectively achieved on the premise that stored data information and retrieval result related information are not leaked.
Owner:XIDIAN UNIV

High-dimensional data similarity connection inquiry method and device based on distance partition tree

The embodiment of the invention provides a high-dimensional data similarity connection inquiry method and device based on a distance partition tree. The method comprises the steps of: acquiring high-dimensional original data, and mapping the original data into a one-dimensional space; according to a first distance threshold and a chi square distribution property, determining a second distance threshold, and according to the original data and the second distance threshold, constructing the distance partition tree; traversing the distance partition tree and carrying out comparison on each node in the distance partition tree to obtain a candidate similar node pair set; and calculating an original distance between the original data included in each candidate similar node pair in the candidatesimilar node pair set, and carrying out comparison on each original distance and the first distance threshold to obtain a similarity inquiry result. The device is used for executing the method. According to the embodiment of the invention, complexity of calculation is reduced by mapping the high-dimensional original data to the one-dimensional space, candidate results can be found with low cost bythe distance partition tree, and a filtering effect is improved, so that inquiry efficiency is greatly improved.
Owner:LUOYANG NORMAL UNIV

High-dimensional data similarity join query method and device based on mapping space partition

Embodiments of the present invention provide a high-dimensional data similarity join query method and device based on mapping space partition. The method comprises: acquiring high-dimensional raw dataand mapping the raw data to one-dimensional space; determining a second distance threshold according to a first distance threshold and the chi-square distribution property, and dividing the one-dimensional space into a plurality of subspaces according to the second distance threshold; determining a number of the subspace corresponding to each raw data; obtaining a candidate data pair according tothe second distance threshold and the numbers of the subspaces; calculating an original distance of the candidate data pair and comparing the original distance with the first distance threshold to obtain a similarity query result. Device for performing a method is provided. As the high-dimensional raw data is mapped to the one-dimensional space, the raw data is divided in the one-dimensional space according to the second distance threshold, and then the similarity inquiry is carried out, and in this way, the computational complexity is lowered, the number of candidate results is reduced, andthe inquiry efficiency is improved.
Owner:LUOYANG NORMAL UNIV
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