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Impact Damage Identification for Composite Material Based on Transmissibility Function and OS-ELM Algorithm
Get PDFA method is proposed based on the transmissibility function and the Online Sequence Extreme Learning Machine (OS-ELM) algorithm, which is applied to the impact damage of composite materials. First of all, the transmissibility functions of the undamaged signals and the damage signals at different points are calculated. Secondly, the difference between them is taken as the damage index. Finally, principal component analysis (PCA) is used to reduce the noise feature. And then, input to the online sequence limit learning neural network classification to identify damage and confirm the damage location. Taking the amplitude of the transmissibility function instead of the acceleration response as the signal analysis for structural damage identification cannot be influenced by the excitation amplitude. The OS-ELM algorithm is based on the ELM (Extreme Learning Machine) algorithm, in-creased training speed also increases the recognition accuracy. Experiment in the epoxy board shows that the method can effectively identify the structural damage accurately
Hierarchical Geographically Weighted Regression Model
Get PDFIn spatial analysis, two problems of the scale effect and the spatial dependence have been plagued scholars, the first law of geography presented to solve the spatial dependence has played a good role in the guidelines, forming the Geographical Weighted Regression (GWR). Based on classic statistical techniques, GWR model has ascertain significance in solving spatial dependence and spatial non-uniform problems, but it has no impact on the integration of the scale effect. It does not consider the interaction between the various factors of the sampling scale observations and the numerous factors of possible scale effects, so there is a loss of information. Crossing a two-stage analysis of “return of regression” to establish the model of Hierarchical Geographically Weighted Regression (HGWR), the first layer of regression analysis reflects the spatial dependence of space samples and the second layer of the regression reflects the spatial relationships scaling. The combination of both solves the spatial scale effect analysis, spatial dependence and spatial heterogeneity of the combined effects
CNN-Based Fast HEVC Quantization Parameter Mode Decision
Get PDFWith the development of multimedia presentation technology, image acquisition technology and the Internet industry, long-distance communication methods have changed from the previous letter, the audio to the current audio/video. And the proportion of video in work, study and entertainment keeps increasing, high-definition video is getting more and more attention. Due to the limits of the network environment and storage capacity, the original video must be encoded to be efficiently transmitted and stored. High Efficient Video Coding (HEVC) requires a large amount of time to recursively traverse all possible quantization parameter values of the coding unit in the adaptive quantization process. The optimal quantization parameter is calculated by comparing the rate distortion cost. In this paper, we propose a fast decision method for HEVC quantization parameters selection based on convolutional neural network, which saves video’s encoding time
Ensuring Readability of Electronic Records Based on Virtualization Technology in Cloud Storage
Get PDFWith the rapid development of E-commerce and E-government, there are so many electronic records have been produced. The increasing number of electronic records brings about storage difficulties, the traditional electronic records center is difficult to cope with the current fast growth requirements of electronic records storage and management. Therefore, it is imperative to use cloud storage technology to build electronic record centers. However, electronic records also have weaknesses in the cloud storage environment, and one of them is that once electronic record owners or managers lose physical control of them, the electronic records are more likely to be tampered with and destroyed. So, the paper builds a reliable electronic records preservation system based on coding theory. It can effectively guarantee the reliability of record storage when the electronic record is damaged, and the original electronic record can be restored by redundant coding, thus ensuring the reliable storage of electronic records
A Novel Steganography Scheme Combining Coverless Information Hiding and Steganography
No full textAt present, the coverless information hiding has been developed. However, due to the limited mapping relationship between secret information and feature selection, it is challenging to further enhance the hiding capacity of coverless information hiding. At the same time, the steganography algorithm based on object detection only hides secret information in foreground objects, which contribute to the steganography capacity is reduced. Since object recognition contains multiple objects and location, secret information can be mapped to object categories, the relationship of location and so on. Therefore, this paper proposes a new steganography algorithm based on object detection and relationship mapping, which integrates coverless information hiding and steganography. In this method, the coverless information hiding is realized by mapping the object type, color and secret information in object detection method. At the same time, the object detection method is used to find the safe area to hide secret messages. The proposed algorithm can not only improve the steganographic capacity of the two information hiding methods but also make the coverless information hiding more secure and robust
A Survey on Digital Image Steganography
No full textInternet brings us not only the convenience of communication but also some security risks, such as intercepting information and stealing information. Therefore, some important information needs to be hidden during communication. Steganography is the most common information hiding technology. This paper provides a literature review on digital image steganography. The existing steganography algorithms are classified into traditional algorithms and deep learning-based algorithms. Moreover, their advantages and weaknesses are pointed out. Finally, further research directions are discussed
SERVQUAL Model Based Evaluation Analysis of Railway Passenger Transport Service Quality in China
No full textRailway is the backbone of Chinese transportation system, but its poor quality of services for passengers cause complains now and then. This study first analyzed the influencing factors of service quality on railway passenger, and its quality characteristics was also explained, and finally we proposed an evaluation system of service quality on railway passenger transport. Through the statistical analysis and processing of the basic information from survey data from railway station, trains and the official website of the ticket purchase, the evaluation score of question naire was converted into the score in evaluation index system, which was based on SERVQUAL model. Finally, the evaluation index system was applied to the field test, and all levels of indicators and the overall evaluation of railway passenger transport service quality was obtained. The relevant results show that the evaluation model of this study is concise and practical, and the method has certain practicability and promotion value, which is beneficial to the department of management supervision in railway transportation
Multi-Scale Variation Prediction of PM2.5 Concentration Based on a Monte Carlo Method
No full textHaze concentration prediction, especially PM2.5, has always been a significant focus of air quality research, which is necessary to start a deep study. Aimed at predicting the monthly average concentration of PM2.5 in Beijing, a novel method based on Monte Carlo model is conducted. In order to fully exploit the value of PM2.5 data, we take logarithmic processing of the original PM2.5 data and propose two different scales of the daily concentration and the daily chain development speed of PM2.5 respectively. The results show that these data are both approximately normal distribution. On the basis of the results, a Monte Carlo method can be applied to establish a probability model of normal distribution based on two different variables and random sampling numbers can also be generated by computer. Through a large number of simulation experiments, the average monthly concentration of PM2.5 in Beijing and the general trend of PM2.5 can be obtained. By comparing the errors between the real data and the predicted data, the Monte Carlo method is reliable in predicting the PM2.5 monthly mean concentration in the area. This study also provides a feasible method that may be applied in other studies to predict other pollutants with large scale time series dat
Application of MES System in Offshore Oil and Gas Field Production Management
No full textIn order to solve information island problem of offshore oil and gas field production-related information system, including repetitive reporting and input of data, data isolation of central control system, inadequate follow-up analysis and development to support oil and gas field production management, and so on. Therefore, the introduction of MES (Manufacturing Execution System) production execution system in the manufacturing industry and downstream production of offshore oil has become an inevitable choice. This system utilizes the real-time database combined with relational database to collect the scattered structured data, such as the production process real-time data, production management documents and statistical tables of offshore oil and gas production facilities. It establishes a unified data center platform for each operation area and production site, so as to centralize the related production management data at production sites. This system realizes many functions, including the production management support like production report generation as well as presentation and POB, equipment management support like PM optimization, remote configuration and monitoring of production operation, status trend analysis, and production event prediction. The implementation of MES system in offshore oil and gas field production management perfects the overall information system of China National Offshore Oil Corporation more and gradually enhances its comprehensive benefits
A Straightforward Direct Traction Boundary Integral Method for Two-Dimensional Crack Problems Simulation of Linear Elastic Materials
Get PDFThis paper presents a direct traction boundary integral equation method (DTBIEM) for two-dimensional crack problems of materials. The traction boundary integral equation was collocated on both the external boundary and either side of the crack surfaces. The displacements and tractions were used as unknowns on the external boundary, while the relative crack opening displacement (RCOD) was chosen as unknowns on either side of crack surfaces to keep the single-domain merit. Only one side of the crack surfaces was concerned and needed to be discretized, thus the proposed method resulted in a smaller system of algebraic equations compared with the dual boundary element method (DBEM). A new set of crack-tip shape functions was constructed to represent the strain field singularity exactly, and the SIFs were evaluated by the extrapolation of the RCOD. Numerical examples for both straight and curved cracks are given to validate the accuracy and efficiency of the presented method