102 results about "Double compression" patented technology

A bone screw assembly for joining bone fragments having a screw shaft, a compression head and a sleeve. The compression head has external threads for providing double compression of the bone fragments. The sleeve extends along and around the screw shaft to provide reinforcing strength and alignment to the screw.

The invention relates to a double compression shear experimental device for material dynamics based on a Hopkinson rod. The experimental device comprises a strain foil (5), an impact rod (3), an incident rod (4) and a transmission rod (7); the experimental device is characterized in that one of the adjacent ends of the incident rod (4) and the transmission rod (7) is a V-shaped groove or a wedgy head, while the other end is a wedgy head or a V-shaped groove; included angles between the bevels of the V-shaped groove and the wedgy head and the axes of the incident rod (4) and the transmission rod (7) are the same and between 30 and 80 degrees; and two test samples are symmetrically clamped between the bevels of the V-shaped groove and the wedgy head. The experimental device does not need to make large change to the Hopkinson pressure rod, only needs to reprocess one incident rod (4) of which one end is provided with the wedgy head or the V-shaped groove and a pressure rod of which one end is provided with the V-shaped or the wedgy head and adopts a test sample of the conventional Hopkinson pressure rod to simultaneously apply the impact load combining compression shear on two test samples. The experimental device has the characteristics that equipment has small occupied area, attractive appearance, elegance and simple operation.

The invention discloses a double compression detection method of a joint photographic experts group (JPEG) image. The method comprises the following steps of: correcting a JPEG image to be detected to obtain a reference image; extracting histograms of quantization discrete cosine transform (DCT) parameters of the JPEG image to be detected and the reference image, and calculating a characteristic value of each frequency according to the histograms; and performing pattern recognition on the characteristic values by using a trained classifier, and judging whether the JPEG image to be detected is subjected to double compression. In the double compression detection method of the JPEG image, because only one characteristic value of each frequency of the JPEG image to be detected and the reference image is extracted, the number of the characteristic values is small, and the training time of the classifier is short; and the characteristic values are effectively extracted, so that judgment accuracy rate is high, and performance is stable. Moreover, the invention also provides a double compression detection system of the JPEG image.

The invention provides an all-optical laser plasma accelerator-based small-sized Gamma ray source. The ray source comprises a synchronous dual-output high-power laser system (200), a double-compression-delay system (12), a laser plasma accelerator (18), a particle beam focusing system (24), a scattered light focusing mirror (27) and a particle beam separation system. A bunch of initial laser pulse is separated and amplified through the laser system (200) to generate two bunches of synchronous high-energy laser pulses (10 and 11); the two amplified laser pulses are compressed in a time domain through the double-compression-delay system (12), and proper delay is performed to form a drive pulse (13)-scattering pulse (14) pair; a drive pulse (13) passes through the laser plasma accelerator (18) to generate a relativistic electron beam (21); the particle beam focusing system (24) is used for transmitting the electron beam (21); the scattered light focusing mirror (27) is used for focusing a scattering pulse (14) to the electron beam (21) so as to generate a gamma ray 31); the separation system is used for separating the electron beam (21) from the gamma ray (31).

The invention relates to an underground packer with a double-compression function and a use method of the packer. According to a double-acting compression type packer, a center pipe of the packer is sleeved with an outer pipe, an outer step at the upper end of the center pipe corresponds to an inner step at the upper end of the outer pipe, the upper end of the outer pipe is sleeved by a rubber barrel sealing mechanism, an anchoring mechanism is arranged in the middle of the outer pipe in a sleeved mode and located under the rubber barrel sealing mechanism, the lower end of the outer pipe is sleeved with a hydraulic mechanism, the hydraulic mechanism is connected with the anchoring mechanism, the lower portion of the outer pipe is provided with square holes in the circumferential direction, a locking block is arranged in one square hole, the locking block radially extrudes out of an inner groove embedded in the hydraulic mechanism, a circumferential groove is formed in the lower portion of the locking block and in the outer periphery of the center pipe, and the positions, under the circumferential groove, of the center pipe and the outer pipe are connected in the axial direction through a shear pin. After the sealing action of the hydraulic mechanism is finished, a rubber barrel is compressed through mechanical force produced when a feeding pipe column presses downward, compressive deformation of the pipe column on the rubber barrel is locked through a locking ring, and therefore contact stress between the rubber barrel and a bush of the packer can be well improved. Therefore, the sealing performance of the packer is improved.

The invention discloses a double JPEG (Joint Photographic Experts Group) compressed image-targeted tempertamper detection method. The tempertamper detection method comprises the steps of: firstly, evaluating the image compression quality factor Q2 by utilizing the header file of a detection image with JPEG format, carrying out first double compression to the detection image by utilizing the quality factor Q2, calculating the square errordifference of corresponding image pixel values before and after the double compression so as to obtain the distortion matrix of the double compression, calculating a local minimum value of the distortion degree to be confirmed as a quality factor Q1, carrying out second double compression to the image subjected to the first double compression by using the quality factor Q1, calculating the square difference of corresponding image pixel values of the image subjected to the second double compression and the detection image to serve as the distortion matrix of the second double compression, conducting tempertamper detection through detecting whether an abnormal area exists in the distortion matrix of the second double compression, displaying the abnormal area in the form of images to obtain the tamper located image display result. According to the inventionmethod, the detection accuracy is high, good robustness on the operation for keeping the contents such as normal image processing and the like is achieved has good robustness, and higher calculation efficiency can be realized.

The invention discloses a steganography detection method for audio subjected to MP3Stego steganography. The method includes the steps of forming a sample library through MP3 compressed audio not subjected to steganography and MP3 compressed audio subjected to steganography, conducting double-compression coding on each sample to obtain carrier estimation of each sample, extracting a quantized MDCT coefficient of each frame in each sample to obtain a first coefficient matrix corresponding to the sample, extracting a quantized MDCT coefficient of each frame in the carrier estimation of each sample to obtain a second coefficient matrix corresponding to the carrier estimation, calculating a Hausdorff distance value between corresponding lines in each first coefficient matrix and the corresponding coefficient matrix to obtain the final steganography analysis characteristic line vector of each sample, obtaining a training template through SVM classifier training, and detecting the MP3 compressed audio to be detected through the training template. The method has the advantages that whether the MP3 compressed audio is subjected to MP3Stego steganography or not can be quite accurately determined, and particularly, the quite high detection efficiency can still be obtained under the condition that the steganography information embedment rate is low.

The invention relates to a test data encoding compression method. The test data encoding compression method comprises the following steps of: segmenting original test data by using L as a data section length, wherein L is a positive integer power of 2; if the length of the last data section is less than L bits, then filling X-bits at the tail part of the last data section to complement the residual bits, and obtaining a plurality of data sections; respectively carrying out external compatibility analysis on the plurality of data sections, carrying out backtracking and value assignment on the X-bits in the data sections according to an external compatibility analysis result; carrying out internal compatibility analysis on the data sections without external compatibility to obtain internal encoding types of the data sections and generate corresponding internal reference data sections; and obtaining encoding code words of the data sections according to an encoding rule and the external compatibility analysis result or according to the encoding rule, the external compatibility analysis result, the internal encoding types and the internal reference data sections. The invention has the characteristics of realizing double compression of the test data and improving test data compression ratio.

The invention relates to a double-compression roller structure for a label delivering machine. The structure comprises a drive roller (1) arranged on a mainboard (2) of the label delivering machine and two groups of compression rollers (3), wherein the two groups of compression rollers (3) have the same structures and are arranged on the two sides of the drive roller (1); a label body paper (21) and a label (22) are pressed on the surface of the drive roller (1) by one of the compression rollers (3); and after the label (22) is separated from the label body paper (21), the label body paper (21) moves around the drive roller (1) of the label delivering device again and is pressed on the surface of the drive roller (1) by the other compression roller (3). By adoption of the invention, during the movement of the label, the label body paper can be equally stressed so that the label body paper cannot be torn even in the state of high-speed movement. The double-compression roller structure for the label delivering machine is reasonable in design, convenient and practical.

The invention discloses a moving picture experts group audio layer-3 (MP3) audio double-compression detection method under same code rate. The MP3 audio double-compression detection method under the same code rate comprises the following steps of firstly acquiring to-be-detected MP3 audios, then, decoding the to-be-detected MP3 audios to obtain decoded WAV audios, then, coding the decoded WAV audios, respectively and correspondingly acquiring scale factor matrixes in a decoding process and a coding process according to the position of every long-window coded frame during the decoding process and the coding processes, extracting a characteristic value in every to-be-detected MP3 audio according to the scale factor matrixes respectively acquired in the decoding process and the coding process, and sending the characteristic values into a trained support vector machine and detecting the characteristic values to determine whether the to-be-detected MP3 audios are MP3 audios after primary compression or MP3 audios after double compression under the same code rate. The MP3 audio double-compression detection method under the same code rate has the advantages that the blank of MP3 audio double-compression detection under the same code rate is filled and the defect of the audio double-compression detection under higher code rate is overcome, and two scale factor matrixes are introduced, so that the computation complexity is lowered.

The invention provides a method for classifying pixel blocks of JPEG images and image falsification detecting and falsified area positioning methods based on the same. The method comprises the following steps of: dividing to-be-detected JPEG images into continuous and non-overlapped 8*8 pixel blocks; taking one pixel block as the center and selecting a square area combined by (2n+1)*(2n+1) pixel blocks as a sub-image; utilizing a first number distribution probability feature of AC coefficients in the front i AC coefficient regions of the sub-image to divide the central pixel block into singlecompression or double compression; and confirming a classifying result as the double compression and a connected region with an area more than M 8*8 pixel blocks as a falsified area. According to themethod provided by the invention, the falsified area can be accurately detected and positioned; the falsified areas of three different falsifying technologies can be detected according to the method;the method is wide in application scope; the method is an automatic blind detecting method for JPEG falsified images and does not require any priori knowledge; and the detection coverage rate is higher and the error detection rate is low.

The invention relates to an tntegral type conveyer with double compression rollers. The integral type conveyer comprises a conveying rack and a conveying platform, wherein a first bevel wheel speed reduction motor, a second bevel wheel speed reduction motor and a conveying platform are arranged on the conveying rack; a flower roller and a smooth roller are arranged on the conveying platform; a double-compression-roller support frame is arranged on the conveying platform; a driving central shaft is arranged on the double-compression-roller support frame and is connected with a flower roller rotary support beam and a smooth roller rotary support beam, so that the flower roller rotary support beam and the smooth roller rotary support beam drive the central shaft to swing. According to the integral type conveyer with double compression rollers, the height difference of the double compression rollers and the conveying platform is respectively adjusted by virtue of a hand wheel, so that the conveyer can be adapted to bags with multiple specifications and multiple materials, the compactness and the flatness of a packaging bag are guaranteed, the operation smoothness of a production line is improved, and the production management cost is reduced; after the packaging bag is finished by the double compression rollers for twice, materials in the packaging bag are uniformly distributed, and the shape is flat, therefore the stacking quality and the operation speed of the production line are improved.

The invention relates to a displacement JPEG (joint photographic experts group) double-compression tampering blind detection method based on a condition symbiotic probability matrix. The method comprises the steps: firstly, carrying out differential and thresholding treatment of horizontal, vertical, main diagonal and secondary diagonal directions on an amplitude matrix of a discrete cosine transform coefficient quantified by a JPEG; then modeling the four thresholding differential matrixes by the condition symbiotic probability matrix; selecting an element of the condition symbiotic probability matrix as characteristic data, and carrying out dimension reduction treatment on the characteristic data by principal component analysis; and finally, judging whether an image block is subjected to displacement JPEG double-compression through a support vector machine technology. An experiment shows that the method has obvious advantages compared with the existing algorithm when the image block is small, so that the practicability of the displacement JPEG double-compression tampering detection is greatly improved, and good foundation is established for further development of the digital image forensics field.

The invention belongs to the technical field of medical appliances and particularly relates to an elastic pressure hemostatic dressing comprising a viscose elastic compression layer, the vicious side of the viscose elastic compression layer is connected with a first cushion layer, and a self-expansion layer is connected to the top end face of the first cushion layer. The elastic pressure hemostatic dressing has the advantages that the dressing is in a double-compression structure, strapping is not required, no movement occurs, hemostasis is efficient, and chances of bleeding and hematoma are slimed.

The invention discloses a double compression detection method towards an MP3 (moving picture experts group audio Layer-3) digital audio file. The double compression detection method towards the MP3 digital audio file includes: using a pattern classification technology to extract features of the MP3 digital audio file; using classifier training and double compression determination to perform double compression detection on the MP3 digital audio file; using the classifier training and source code rate determination to perform source code rate detection on the MP3 digital audio file. The double compression detection method towards the MP3 digital audio file is based on calibration, uses difference value of numbers of average frame quantization MDCT coefficients of an original audio file and a calibrated audio file, which are equal to figures from 0 to 9, as the features to perform the detection, can solve the puzzles in detection of double compression at the same bit rate and double compression at bit rate from high to low as shown in experimental results, not only can identify whether the MP3 digital audio file is compressed or not, but also can accurately determine original compression code rate of the MP3 digital audio file, and thereby provides the basis for audio tamper detection.

The invention relates to a motion vector domain video steganography method based on a novel embedding cost. The novel embedding cost construction method gives fully consideration to affects on motion characteristics, motion vector local optimality and motion vector statistic distribution of a video content because of motion vector alteration and uses weight parameters to regulate distribution proportion of three costs in a novel cost. The motion vector domain video steganography method adopts an adaptive selection strategy when selecting a replaceable motion vector, can effectively maintains the local optimality of the motion vector, and, particularly under a condition of high bit rate, can obtain higher safety compared with the current steganography method. The motion vector domain video steganography method can effectively resist multiple steganalysis like the steganalysis method based on the local optimality, the steganalysis method based on double compression, etc.

The invention discloses a JPEG image double-compression automatic detection method, and the method comprises the steps: carrying out the preprocessing of a JPEG image; extracting a first effective number feature of a DCT coefficient and adjacent coefficient difference features of the JPEG image based on the Markov model, carrying out the fusion of the features, and carrying out the feature dimension reduction; and training and recognizing a support vector machine. The fusion features can be effectively used for various compression conditions (besides the common compression conditions, also comprising a condition that two compression qualities are equal and the second compression quality is 95). Moreover, after the extraction of the fusion features, the dimension reduction of a feature matrix is carried out, and the matrix after dimension reduction is taken as a feature vector for subsequent operation. The method reduces the calculation complexity, improves the algorithm efficiency, and is easy to use in reality.

The invention provides a laminated matrix decomposition-based low frequency electromagnetic property simulation method. Firstly, the problem of low frequency collapse of the conventional electric field integral equation method is eliminated by employing an augmented electric field integral equation method; a low frequency multi-level fast multi-pole method is adopted to establish a laminated matrix expression for the coefficient matrix of the augmented electric field integral equation; the laminated matrix is further compressed by using a double compression method to remove redundant information; finally, a laminated matrix format algorithm is adopted to perform upper-lower triangular decomposition on the compressed laminated matrix. The laminated matrix decomposition can reduce calculating complexity and memory consumption to be almost linear; a precondition technology is constructed for an iteration solution and a direct solution is constructed. The method has the advantages of high solving speed, low memory consumption and precision controllability and can be applied to various kinds of low frequency electromagnetic property analysis.

Provided is a gas circuit breaker. The gas circuit breaker includes a fixed part, a movable part, a piston, and a double compression mechanism. The fixed part includes a fixed arc contact and a first fixed contact maker. The movable part includes a movable arc contact selectively making contact with the fixed arc contact, a cylinder in which the movable arc contact is disposed, and a second fixed contact maker guiding a movement of the cylinder. The piston is disposed in the second fixed contact maker. The double compression mechanism is configured to move the piston in a direction opposite to a moving direction of the movable part when the movable part is moved to separate the fixed arc contact and the movable arc contact for interrupting a fault current.

The invention discloses a method, a device and equipment of data warehouse-in. The method includes: starting a high-speed Huffman compression algorithm, which includes a quick sorting algorithm, to carry out first data compression on written data to generate firstly compressed file; after the firstly compressed file is written into an Hbase database table, calling a double compression algorithm torealize second data compression on the firstly compressed file, and outputting a secondly compressed file; and realizing data warehouse-in of a Hadoop distributed file system (HDFS) on the basis of the secondly compressed file. After employing the embodiment of the invention, IO pressure of a network and a disk can be alleviated, and data warehouse-in performance can be guaranteed.

The invention discloses an image compression method and device. The method comprises the following steps of adopting an initial quality factor for obtaining an input image; computing an objective quality assessment score of the input image after double compression processing according to the initial quality factor and a preset minimum quality factor; carrying out adaptive adjustment on the quality factor of the input image according to the objective quality assessment score, a preset objective quality assessment score of the image, which is corresponding to the type of the input image, and a preset rule, stopping a compression process until the objective quality assessment score for image compression meets a preset threshold range, and computing to obtain a first quality factor; carrying out fine tuning on the first quality factor according to subjective image quality factor priori knowledge obtained based on mass data knowledge, and determining a second quality factor; and carrying out compression processing on the input image according to the first quality factor and the second quality factor. According to the image compression method and device, a problem that the visual quality effect is low when the image compression rate is higher, and the visual quality effect for image compression is improved.

The invention provides a double-compression detection method by using a quantification factor same as an H.264 video. The method comprises the steps of 1, acquiring intra-frame prediction macro block modes of all macro blocks of an I frame by decoding an input video; 2, coding a YUV sequence by using the quantification factor same as the previous input video, thus acquiring the next input video, and acquiring the intra-frame prediction macro block modes of the all macro blocks of the I frame of the video; 3, repeating the step 2 for K times, and computing the average quantity Cn of the macro blocks of which the intra-frame prediction macro block modes change in each I frame between the videos of adjacent compression visions; 4, respectively dividing the Cn acquired by K times by the total quantity of the corresponding macro blocks in the single frame of the video, and constituting results into a K-dimensional characteristic vector; and 5, judging whether the video is subjected to the double compression of the same quantification factor by using a characteristic vector training classifier of a training video set. The method provided by the invention is high in accuracy and has good robustness for the different quantification factors and video resolution.

The invention discloses a rotary compressor which includes the casing, the electromotion part and the compression part. The electromotion part locates on the top of the casing; the compression part which includes cylinder, rolling hoop, top axletree and lower axletree locates inside and on the bottom of the casing; there is compression cavity with some cubage in the cylinder; the sucking hole communicates with the compression cavity; the bypass opening locates the place which is some distance away the sucking hole; the discharge hole discharges the compressed gas from the compression cavity. The rolling hoop eccentrically connects with the rotation axis, rolls on the inner surface of the compression cavity and divides the space which is used for sucking and compression together with the inner surface. The spacing block is set between the sucking hole and the discharge hole, maintains spring contact with the rolling hoop and divides the compression cavity into sucking space and the discharge space. The makeandbreak unit selects and opens or closes the by-pass port according to compression module. The invention can get double compression energy by a compressor, provide adequate compression energy corresponding to the run condition realizes double compression energy and saves electric power.