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65results about How to "Reduce time and space complexity" patented technology

Network hot event detection method based on text classification and clustering analysis

The invention discloses a network hot event detection method based on text classification and clustering analysis. The method solves the problem that the efficiency and accuracy rate of the existing network hot event detection method based on clustering analysis need to be improved. The method comprises the steps that feature words are respectively selected for various classes of files through feature extraction and feature selection by utilizing a training corpus; each training text and test text are represented as vectors in all of the feature spaces by utilizing a vector space model method, and the weight of each dimension of the vectors is determined by utilizing a TF-IDF (term frequency-inverse document frequency) method, and then each test text is classified; the classified test texts in different classes are respectively subjected to clustering analysis, so the hot cluster of each class is obtained, the feature word representing the hot event is obtained through further analysis, and then the word property and other aspects of each feature word are analyzed; the description of each hot event is generated by utilizing relevant language knowledge and necessary linguistic organization. With the network hot event detection method based on text classification and clustering analysis, the detection efficiency and accuracy rate of hot events can be effectively improved.
Owner:NANJING UNIV OF POSTS & TELECOMM

Fatigue driving state detecting system and method based on decision-making level data integration

The invention discloses a fatigue driving state detecting system and method based on decision-making level data integration. The fatigue driving state detecting system firstly uses an acceleration sensor to acquire motion acceleration of a steering wheel, judges motion states of the steering wheel based on dynamic acceleration threshold values, and primarily judges fatigue driving states of a driver based on 4s immobility theory. Detecting error tolerance is improved by setting errors of the steering wheel turning from left to right. Pulse time domain values of the driver can be acquired via a pulse sensor, and physiological states of the driver can be detected based on dynamic pulse threshold values. Integrated detecting results can be obtained by integrating two kinds of detecting results in decision making level. By the fatigue driving state detecting method based on decision-making level data integration, a fatigue driving state detecting prototype system is constructed. Compared with existing methods, the fatigue driving state detecting method based on decision-making level data integration has certain advantages in detection accuracy and perfect performance in response time, time complexity, memory occupation and the like of algorithms.
Owner:NANJING UNIV OF POSTS & TELECOMM

Speaker confirmation method and speaker confirmation device used in short voice condition

InactiveCN105845140AImprove legibilityLittle impact on recognition rateSpeech analysisFeature vectorFrequency spectrum
The invention relates to a speaker confirmation method and a speaker confirmation device used in a short voice condition. The method comprises the steps of extracting a linear prediction cepstral coefficient, a Mel frequency cepstral coefficient and a Delta characteristic from an objective voice signal; combining the linear prediction cepstral coefficient, the Mel frequency cepstral coefficient and the Delta characteristic, thereby obtaining a plurality of effective characteristic vectors; reducing the dimension number of the effective characteristic vectors by means of a partial fuzzy PCA method; and modeling by means of the dimension-reduced effective characteristic vectors according to a Gaussian mixture model, and identifying the speaker of the objective voice signal. Compared with the prior art, the speaker confirmation method and the speaker confirmation device are advantageous in that a single characteristic is replaced by a characteristic combination, thereby improving number of dimensions of the effective characteristics and compensating defects of a characteristic sample, and furthermore the local fuzzy PCA is used for performing effective dimension reduction on the combined characteristic, thereby reducing time-space complexity of the system under a precondition of low effect on identification rate.
Owner:SPEAKIN TECH CO LTD

Method and device for retrieving similarity of picture messages

The invention discloses a method and a device for retrieving the similarity of pictures and belongs to the field of the graphic images. The method comprises the steps of obtaining the to-be-retrieved picture characteristics of to-be-retrieved pictures, hashing the to-be-retrieved picture characteristics by use of an LSH (Locality Sensitive Hashing) algorithm to generate hash values of the to-be-retrieved pictures, finding database picture hash values of which are matched and similar to the hash values of the to-be-retrieved pictures om a hash table corresponding to every hash values of the to-be-retrieved pictures, finding database pictures according to the database picture hash values, and according to Euclidean distances of the characteristics of the database pictures and the characteristics of the to-be-retrieved pictures, selecting a preset number of database pictures from the database pictures having relatively smaller Euclidean distances. The method and the device have the characteristics that the problem that a user cannot retrieve the most similar pictures from a plurality of results obtained by the LSH algorithm at the present is solved, and the advantages of LSH in reducing the time-space complexity in picture similarity retrieval and supporting high-dimensional data retrieval are better developed by virtue of the combination of the LSH algorithm and a linear retrieval algorithm.
Owner:BEIJING FEINNO COMM TECH

Audio-video fingerprint generation method based on key frames

The invention discloses an audio-video fingerprint generation method based on key frames. The audio-video fingerprint generation method comprises the following steps: firstly extracting a plurality of the key frames from an I-frame of video data based on a minimum vertex covering principle so as to reduce fingerprint expenditure; then by virtue of characteristics of DCT (discrete cosine transform) coefficients of the I-frame, selecting a direct current (DC) coefficient x<0> and N low-frequency alternating current (AC) coefficients x<1>, x<2>...and x<N> with minimum frequency of the key frames, generating a 0/1 sequence with N+1 digits by a quantization coding mode, converting timestamps of the key frames into a binary sequence, and placing the binary sequence in front of the 0/1 sequence with the N+1 digits so as to form a video frame fingerprint with M-1 digits for the key frames; and by virtue of characteristics of exclusive OR (XOR) operation, and uniting audio and video fingerprints into one, an audiovisual fingerprint is generated through the matching and synchronous authentication of the timestamps. The audio-video fingerprint generation method has the advantages of achieving the purpose of authenticating a plurality of media data at the same time through one fingerprint, greatly reducing the fingerprint expenditure and realizing certain error location, error detection and repair functions on problems such as incorrect playback and error playback of audio-video programs, insertion of illegal programs, program interpolation and the like.
Owner:UNIV OF ELECTRONIC SCI & TECH OF CHINA

Fabric weft inclination rapid-detection method based on machine vision

InactiveCN103866551ASimple Effective Noise PixelsRemove noise pixelsInspecting textilesRapid detectionVideo camera
The invention discloses a fabric weft inclination rapid-detection method based on machine vision. The method comprises the following steps that a CCD video camera is adopted to collect texture images of fabrics, the best segmentation threshold value T is automatically found by using the Otsu method, image target and background segmentation is conducted on the texture images of the fabrics according to the best segmentation threshold value T, and binary texture images of the fabrics are obtained; the stripe trend in the binary texture images of the fabrics is tracked in a window pixel searching method, isolated point noise is removed, a stripe tracking starting point and end point are determined, and finally the stripe weft inclination angle is obtained; a plurality of stripes are tracked by adopting a stripe space domain retraining method, a set of stripe weft inclination angle values are obtained, selective averaging is conducted on the stripe weft inclination angle values, and final fabric stripe image weft inclination angle values are obtained. The method effectively avoids influence on weft inclination angle detection of environment light, is high in fabric weft inclination angle detection accuracy, and can rapidly detect the fabric weft inclination angle in real time.
Owner:NANJING UNIV OF SCI & TECH

Field observation data transmission method and device

The invention discloses a field observation data transmission method and device. The device comprises data transmission devices of a sending terminal and a receiving terminal, and the data transmission devices of the sending terminal and the receiving terminal separately comprise two parts, namely a protocol board and a data radio station board card. The transmission method comprises the followingsteps: improving a response mechanism, a timeout mechanism and a window mechanism of a selection-retransmission ARQ; extracting observation data, and sending the observation data to a data receivinghost; and finally integrating a power management function and a working time management function on the protocol board. The field observation data transmission method and device disclosed by the invention have the advantages that after the realization processes of various reliability protocols are analyzed, the low-power-consumption design is incorporated into the protocol improvement, and under the assistance of the power management on the respect of the hardware system, the transmission power consumption can be effectively reduced during field data transmission, the volume is small and the cost is low.
Owner:COLD & ARID REGIONS ENVIRONMENTAL & ENG RES INST CHINESE

Autonomous ship route planning method based on D*Lite optimization algorithm

ActiveCN111220160AReal-time dynamic replanningReal-time dynamic programmingInternal combustion piston enginesNavigational calculation instrumentsSimulationRoute planning
The invention provides an autonomous ship route planning method based on a D*Lite optimization algorithm. The method comprises the steps that S1, in the navigation process of an autonomous ship, obtaining environment information according to a preset time interval, and according to the currently obtained environment information and the environment information obtained last time, if the environmentinformation in a current target map area is changed, judging whether a target route point of the autonomous ship is changed or not; and S2, if the target path point is changed, updating the target route point, taking the current route point as a navigation starting point, determining a termination point according to the updated target route point, and planning a route for the autonomous ship to continue to sail by adopting the D*Lite algorithm according to the environmental information, the navigation starting point and the termination point in the current target map area, wherein the targetmap area is a map area influencing route planning between the current route point and the target route point. When the position of the target route point is changed in the navigation process of the autonomous ship, the route can be dynamically replanned in real time.
Owner:智慧航海(青岛)科技有限公司
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