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Multi-granularity temporal structure representation based outlier detection method for prediction of oil reservoir
MENG Fan, CHEN Guang, WANG Yong, GAO Yang, GAO Dequn, JIA Wenlong
Journal of Computer Applications    2021, 41 (8): 2453-2459.   DOI: 10.11772/j.issn.1001-9081.2020101867
Abstract293)      PDF (1265KB)(258)       Save
The traditional methods for prediction of oil reservoir utilize the seismic attributes generated when seismic waves passing through the stratum and geologic drilling data to make a comprehensive judgment in combination with the traditional geophysical methods. However, this type of prediction methods has high cost of research and judgement and its accuracy strongly depends on the prior knowledge of the experts. To address the above issues, based on the seismic data of the Subei Basin of Jiangsu Oilfield, and considering the sparseness and randomness of oil-labeling samples, a multi-granularity temporal structure representation based outlier detection algorithm was proposed to perform the prediction by using the post-stack seismic trace data. Firstly, the multi-granularity temporal structures for the single seismic trace data was extracted, and the independent feature representations were formed. Secondly, based on extracting multiple granularity temporal structure representations, feature fusion was carried out to form the fusion representation of seismic trace data. Finally, a cost-sensitive method was utilized for the joint training and judgement to the fused features, so as to obtain the results of oil reservoir prediction for these seismic data. Experiments and simulations of the proposed algorithm were performed on an actual seismic data of Jiangsu Oilfield. Experimental results show that the proposed algorithm is improved by 10% on Area Under Curve (AUC) compared to both of the Long Short-Term Memory (LSTM) and Gated Recurrent Unit (GRU) algorithms.
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Correspondence property-based platform configuration attestation
XU Mingdi, GAO Yang, GAO Xueyuan, ZHANG Fan
Journal of Computer Applications    2018, 38 (2): 337-342.   DOI: 10.11772/j.issn.1001-9081.2017082168
Abstract331)      PDF (904KB)(384)       Save
Concerning the security problem of local and global attacks on the Integrity Report Protocol (IRP), the StatVerif syntax was extended by adding constructors and destructors associated with the integrity measurement. The security of the Platform Configuration Attestation (PCA) was analyzed and the local and global attacks were found, including tampering the platform configuration register or revising stored measurement log by running unauthorized commands. The abilities of attackers were modeled, and how attackers accumulated knowledge and tampered PCA protocol by using constructors and destructors was introduced. Finally, the existence of attacking sequence was proved theoretically when PCA does not satisfy the correspondence property; and several propositions that PCA can meet the local reliability and gloabal reliability were given, which were proved by the formal verification tool Proverif.
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Whole process optimized garbage collection for solid-state drives
FANG Caihua, LIU Jingning, TONG Wei, GAO Yang, LEI Xia, JIANG Yu
Journal of Computer Applications    2017, 37 (5): 1257-1262.   DOI: 10.11772/j.issn.1001-9081.2017.05.1257
Abstract1085)      PDF (1128KB)(526)       Save
Due to NAND flash' inherent restrictions like erase-before-write and a large erase unit, flash-based Solid-State Drives (SSD) demand garbage collection operations to reclaim invalid physical pages. However, the high overhead caused by garbage collection significantly decrease the performance and lifetime of SSD. Garbage collection performance will be more serious, especially when the data fragments of SSD are frequently used. Existing Garbage Collection (GC) algorithms only focus on some steps of the garbage collection operation, and none of them provids a comprehensive solution that takes into consideration all the steps of the GC process. On the basis of detailed analysis of the GC process, a whole process optimized garbage collection algorithm named WPO-GC (Whole Process Optimized Garbage Collection) was proposed, which integrated optimizations on each step of the GC in order to reduce the negative impact on normal read/write requests and SSD' lifetime at the greatest extent. Moreover, the WPO-GC was implemented on SSDsim which is an open source SSD simulator to evaluate its efficiency. The experimental results show that the proposed algorithm can decreases read I/O response time by 20%-40% and write I/O response time by 17%-40% respectively, and balance wear nearly 30% to extend the lifetime, compared with typical GC algorithm.
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Online incentive mechanism based on reputation for mobile crowdsourcing system
WANG Yingjie, CAI Zhipeng, TONG Xiangrong, PAN Qingxian, GAO Yang, YIN Guisheng
Journal of Computer Applications    2016, 36 (8): 2121-2127.   DOI: 10.11772/j.issn.1001-9081.2016.08.2121
Abstract1063)      PDF (1144KB)(702)       Save
In big data environment, the research on mobile crowdsourcing system has become a research hotspot in Mobile Social Network (MSN). However, the selfishness of individuals in networks may cause the distrust problem of mobile crowdsourcing system. In order to inspire individuals to select trustful strategy, an online incentive mechanism based on reputation for mobile crowdsourcing system named RMI was proposed. Combining evolutionary game theory and Wright-Fisher model in biology, the evolution trend of mobile crowdsourcing system was studied. To solve free-riding and false-reporting problems, the reputation updating methods were established. Based on the above researches, an online incentive mechanism was built, which can inspire workers and requesters to select trustful strategies. The simulation results verify the effectiveness and adaptability of the proposed incentive mechanism. Compared with the traditional social norm-based reputation updating method, RMI can improve the trust degree of mobile crowdsourcing system effectively.
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Multi-source irrigation information fusion method based on fuzzy rough set and D-S evidence theory
CHEN Zhifang WANG Jinglei SUN Jingsheng LIU Zhugui SONG Ni GAO Yang
Journal of Computer Applications    2013, 33 (10): 2811-2814.  
Abstract588)      PDF (605KB)(477)       Save
Concerning the problem that uncertainty information is difficult to be merged during the decision-making process of multi-source irrigation information, a decision fusion method based on fuzzy rough set and Dempster-Shafer (D-S) evidence theory was proposed. Using the fuzzy rough set theory,the basic probability distribution function was established, the interdependence between irrigation factors and irrigation decision was calculated, and the identification framework of irrigation decision on the multiple fusion irrigation factors was built. Using the improved D-S evidence theory, the multi-source irrigation information was fused at the decision-making level, the expression and synthesis problems of uncertain information were solved. The information of winter wheat such as soil moisture, photosynthetic rate and stomatal conductance in north China was fused in irrigation decision by the application of the methods mentioned above. The results show that the uncertainty of the irrigation decision decreases from 38.0% before fusion to 9.84%. The method can effectively improve the accuracy of irrigation decision and reduce the uncertainty of the irrigation decision.
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Echo cancellation technique solutions based on parallel filter
WANG Zhen-chaoZhenchao GAO Yang XUE Wenling YANG Jianpo
Journal of Computer Applications    2013, 33 (07): 1839-1841.   DOI: 10.11772/j.issn.1001-9081.2013.07.1839
Abstract832)      PDF (469KB)(439)       Save
To improve the convergence rate of digital repeater echo cancellation, firstly, the echo cancellation technique based on adaptive filter was studyed; secondly, the recursion algorithm of adaptive filter was improved by the technical schemes that two adaptive filters compute in parallel and update the weights jointly and recursively. Since the error signal to adjust weights of the two adaptive filters was generated in different ways, the schemes were divided into two categories: scheme one is that the weights of two filters were adjusted by error signal of echo cancellation (simultaneously); scheme two is that the weights of the first filter were adjusted by error signal as the difference value of received signal from antenna and output signal of the first filter; and the weights of the second filter were adjusted by error signal as the difference value of the above-mentioned error signal and the output signal of the second filter (separately). The simulation results show that the convergence rate of the echo cancellation is increased by 11.11%~17.78% in the improved technique scheme, so as to improve the condition effectively with the slow convergence rate of digital repeater echo cancellation.
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Security assurance capability assessment based on entropy weight method for cryptographic module
SU Deng-yin XU Kai-yong GAO Yang
Journal of Computer Applications    2012, 32 (01): 115-118.   DOI: 10.3724/SP.J.1087.2012.00115
Abstract994)      PDF (556KB)(592)       Save
To solve the problems that the index value of cryptographic modules is not fixed, the index system is hardly built, and the security assurance ability can not be quantitatively assessed, a security assurance capability assessment for cryptographic module was proposed. The description on indexes by interval number was applied to illustrate the security attribute of cryptographic modules. This paper determined the weight vector of each period point by entropy weight coefficient method combined with expert decision weight method. According to the interval multi-attribute decision methodology, a feasible methodology was adopted to solve the interval Information Assurance (IA) capability evaluation problem of cryptographic modules. Finally, through analyzing two kinds of cryptographic modules, the experimental results show that the proposed method is feasible.
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