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Copyright of Lubrication Engineering (0254-0150) is the property of Editorial Office of LUBRICATION ENGINEERING and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The infectious disease prevention information system has the problems that data is difficult to circulate and share between monitoring systems.To solve these problems,this paper proposed an infectious disease data sharing model based on delegated proof of stake consensus algorithm combined with blockchain technology.By virtue of the characteristics of the blockchain,such as decentralization,non-tampering and collective maintenance,it used double-chain as the blockchain architecture,which improved the work efficiency.Combined with inter-planetary file system,it obtained large capacity storage space,which solved the space problem faced by block data storage and ensured the stability and sharing security of data storage.This paper proposed a consensus algorithm for disease prevention and control to realize the efficient operation.In addition,by comparing with other data sharing models,the advantages of this model in data storage and sharing security are highlighted. [ABSTRACT FROM AUTHOR]

Copyright of Computer Measurement & Control is the property of Magazine Agency of Computer Measurement & Control and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Most overlapping community detecting algorithms ignored the similarity of non-adjacent edges,which reduced the accuracy of overlapping community detection. This paper proposed an overlapping community detecting algorithm based on link distance matrix( LDM). Firstly,based on the link-node-link random walk model and superposed random walk index,this paper proposed a method to calculate the similarity of the non-adjacent edges in the network,which improved the utility of edge information. Then it used the fuzzy clustering methods to deal with link distance matrix to obtain the edge community structure.Finally it adjusted and optimized the overlapping community structure of the network according to the extension module degree function. Compared with existing algorithms in LFR artificial networks and real networks,the experiment results show that the LDM algorithm can effectively improve the accuracy of overlapping community detection algorithm. [ABSTRACT FROM AUTHOR]

Benefiting from its stability and efficiency, low-cost storage capability, Hadoop distributed file system HDFS has been widely used in many large enterprises. However, processing massive small files on HDFS costs too much memory o-verhead of NameNode, and the efficiency of accessing small files from merged file is not satisfactory. To deal with these two issues, this paper proposes an optimizing strategy for storing and accessing small files, that is Small Files Storage Strategy Based on Hybrid Index. Firstly, the strategy classifies and marks small files by a classifier. Secondly, H - B +_tree index on NameNode and different block index on DataNode are created to improve small file access efficiency. Finally, to enhance the response speed of the client access request, cache structure is used to release memory load of NameNode. The experimental results indicate that the strategy is able to improve small file access efficiency, and significantly reduce the memory overhead of NameNode. [ABSTRACT FROM AUTHOR]

Aiming to the issues of low processing efficiency of small files in HDFS, from the perspective of researching correlation between user's accessing regulation and data attributes, this paper treated user accessing streams as request sequences to data files, and parameterized these data on the basis of its spatial and temporal properties. When it generalized new signature sequences by feature extraction, the feature templates of different access modes were found through sequential pattern mining by PrefixSpan algorithm. Experimental results show that the consolidation strategy effectively reduces the NameNode memory usage and response time, and improves the system read efficiency. [ABSTRACT FROM AUTHOR]

For protecting sensitive data stored on computer disks, this paper presented a data hiding method based on disk slack space. Based on analyzing disk partitioning scheme and file management mechanism of cluster-based file system, it made dispersed file-cluster slack spaces organic combination to store sensitive data, and maintained data which was used to restore the original data by using data structure which was stored in partitioning-scheme slack spaces. Experimental results show that data hiding method based on disk slack space does not take up the file system effective space, has characteristics of high concealment, low system overhead, positive correlation between hiding capacity and overall number of files within file system, and anti-interference performance is susceptible to the stability of host files. Moreover, hiding capacity will be very considerable when overall number of files is large, and anti-interference performance can be improved by selecting host files with good stability. [ABSTRACT FROM AUTHOR]

This paper studied the capacity of resisting rotational attack of Luffa hash function. Through analyzing characteristics of Luffa permutation, it defined the rotational pair of Luffa permutation, gave the influence of basic word transformations to rotational relation, proved that the AND operation and the OR operation had the same influence on rotational relation, and presented the distinguisher algorithm between round-reduced Luffa permutation and a random permutation. Theoretical analysis and experiment results show that 3 round Luffa permutation can't resist rotational attack and the attack complexity is only 216. [ABSTRACT FROM AUTHOR]

Frequent itemsets mining, which is the basic in the field of data stream mining, has been paid more and more attention by researchers. Due to the uncertainties, continuities and large amount of data streams, many mining algorithms are difficult to deal with these dynamic data streams. In this paper, hashed table and the interesting degree of association rules are introduced, where the former is used to represent the synoptic data structure and the latter is applied to incorporate attention of customers. After that, a new frequent itemsets mining algorithm named MIFS-HT(mining interesting frequent itemsets with hash table) is proposed. Comparing with lossy counting and a similar algorithm called mining frequent item sets over data streams by matrix (MISM for short), the result shows that MIFS-HT is more effective both in time and space efficiency. [ABSTRACT FROM AUTHOR]

The frame and data structures of CFD solver are studied in this paper. Firstly, the requirements for frame and data structure design are reviewed. Then, a frame based on Object-Oriented technique is presented. The defined basic classes in the frame are discussed in details. Meanwhile, a concept of 'Running Data-base' is introduced in CFD software programming to store and update all kinds of data during the computations. Based on the study, a CFD code, named as HyperFlow, is developed. HyperFlow can run synchronously the structured solver on structured grids and unstructured solver on unstructured grids. Finally, some numerical results are shown to validate the performance of HyperFlow. [ABSTRACT FROM AUTHOR]

Aiming at the bandwidth mismatch between record process and convert process in high-speed data recording system, factors that affect convert process bandwidth are analyzed, and a more flexible and practical data recording method based on file system is proposed. The method divides storage memory into consecutive information management space and data storage space by establishment of file system in advance. In record process, data is recorded in data storage space consecutively and in convert process, information management space is modified. Thus, without decreasing record bandwidth, the method could improve the bandwidth in convert process to achieve high-speed file conversion. [ABSTRACT FROM AUTHOR]

In order to solve the problem that features with high frequency can not be used to obtain clustering results with high quality cause of their incomplete reflection of the document's topic, and to obtain the nice description of information described by each cluster, lexical chains were used to reflect the document's topic and similar documents were clustered according to the similarity between different lexical chains. Then the lexical chains describing the same topic information in the same cluster were combined. Via analyzing the distribution of each topic clew among different clusters, the keyword sets that can completely reflect the topic of each cluster were extracted. Experimental results demonstrate that clustering results obtained by this method outperform those obtained by using features with high frequency to cluster documents, and the extracted keyword sets can reflect the emphasis information of each cluster. [ABSTRACT FROM AUTHOR]