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Strongly connected components based efficient computation of page rank

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Frontiers of Computer Science 2018年第6期12卷 1208-1219页

作者： Hongguo YANG Derong SHEN yue KOU Tiezheng NIE ge yu School of Computer Science and Engineering Northeastern UniversityShenyang 110004China

In this paper, an efficient page rank (PR) exact algorithm is proposed, which can improve the computation efficiency without sacrificing results accuracy. The existing exact algorithms are generally based on the original power method (PM). In order to reduce the number of I/Os required to improve efficiency, they partition the big graph into multiple smaller ones that can be totally fitted in memory. The algorithm proposed in this paper can further reduce the required number of I/Os. Instead of partitioning the graph into the general subgraphs, our algorithm partitions graph into a special kind of subgraphs: SCCs (strongly connected components), the nodes in which are reachable to each other. By exploiting the property of SCC, some theories are proposed, based on which the computation iterations can be constrained on these SCC subgraphs. Our algorithm can reduce lots of I/Os and save a large amount of computations, as well as keeping the results accuracy. In a word, our algorithm is more efficient among the existing exact algorithms. The experiments demonstrate that the algorithms proposed in this paper can make an obvious efficiency improvement and can attain high accurate results.

关键词： page rank strongly connected component power method I/Os

Discovering context-aware conditional functional dependencies

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Frontiers of Computer Science 2017年第4期11卷 688-701页

作者： yuefeng DU Derong SHEN Tiezheng NIE yue KOU ge yu College of Information Science and Engineering Northeastern University Shenyang 110819 China

Conditional functional dependencies（CFDs） are important techniques for data consistency. However, CFDs are limited to 1） provide the reasonable values for consistency repairing and 2） detect potential errors. This paper presents context-aware conditional functional dependencies（CCFDs） which contribute to provide reasonable values and detect po- tential errors. Especially, we focus on automatically discov- ering minimal CCFDs. In this paper, we present context rela- tivity to measure the relationship of CFDs. The overlap of the related CFDs can provide reasonable values which result in more accuracy consistency repairing, and some related CFDs are combined into CCFDs. Moreover, we prove that discover- ing minimal CCFDs is NP-complete and we design the pre- cise method and the heuristic method. We also present the dominating value to facilitate the process in both the precise method and the heuristic method. Additionally, the context relativity of the CFDs affects the cleaning results. We will give an approximate threshold of context relativity accord- ing to data distribution for suggestion. The repairing results are approved more accuracy, even evidenced by our empirical evaluation.

关键词： conditional functional dependencies contextaware rules discovery

X-Ray Properties of PSR J1811-1925 by Nu STAR

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Research in Astronomy and Astrophysics 2023年第11期23卷 51-59页

作者： Jin-Tao Zheng Ming-yu ge Xiang-Hua Li Department of Astronomy Yunnan UniversityKunming 650090China Key Laboratory for Particle Astrophysics Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China

We analyzed the spectral properties and pulse profile of PSR J1811-1925,a pulsar located in the center of composite supernova remnant(SNR)G11.2-0.3,by using high timing resolution archival data from the Nuclear Spectroscopic Telescope Array Mission(NuSTAR).Analysis of archival Chandra data over different regions rules out the SNR shell as the site of the hard X-ray emission while spectral analysis indicates that the NuSTAR photons originate in the pulsar and its *** pulse profile exhibits a broad single peak up to 35 *** jointed spectrum by combining NuSTAR and Chandra can be well fitted by a power-law model with a photon index ofΓ=1.58±*** integrated flux of jointed spectrum over 1-10 keV is 3.36×10^(-12)erg cm^(-2)s^(-1).The spectrum of pulsar having photon indexΓ=1.33±0.06 and a 1-10 keV flux of 0.91×10^(-12)erg cm^(-2)s^(-1).We also performed the phase-resolved spectral analysis by splitting the whole pulse-on phase into five phase *** photon indices of the bins are all around 1.4,indicating that the photon index does not evolve with the phase.

关键词： (stars:)pulsars:individual(PSR J1811-1925) stars:neutron methods:data analysis

Optimizing Distributed Top-k Queries on Uncertain Data

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Optimizing Distributed Top-k Queries on Uncertain Data

A lock-free approach to parallelizing personalized PageRank computations on GPU

第25届中国控制与决策会议

作者： Zhao Zhibin yu Yang Bao yubin yu ge School of Information Science and Engineering Northeastern University

ISBN: (纸本)9781467355339

With the advances in technology of CPS （Cyper Physical System）, it is found that uncertain data arises in many important domains, such as WSN, RFID, P2P system, and so on. It poses a great challenge on Top-k query processing, which is a very common and crucial application in data management. In this paper, we summarize several semantics of top-k queries on uncertain data and propose an optimized algorithm DMPUTop-k for processing most probable uncertain Top-k queries（MPUTop-k） in the distributed environment. In addition, we analyze the equivalence between MPUTop-k and UTop-k in some special cases. The experiments on real dataset show that our technique can greatly reduce the bandwidth consumption for processing Top-k queries in distributed uncertain dataset.

关键词： Top-k query uncertain data distributed environment optimization transmission cost

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Frontiers of Computer Science 2023年第1期17卷 219-220页

作者： Zhigang WANG Ning WANG Jie NIE Zhiqiang WEI yu GU ge yu Faculty of Information Science&Engineering Ocean University of ChinaQingdao 266100China School of Computer Science and Engineering Northeastern UniversityShenyang 110819China

1 Introduction Personalized PageRank(PPR)is a classic topology-based proximity measure and it is most widely computed by Forward *** is,given a starting vertex in graph,it iteratively computes the importance score of any vertex in with respect to,and then broadcasts the new score as messages to’s neighboring *** process converges until all scores hold ***,Graphical Processing Units(GPU)with massive threads has been extensively used to parallelize such compute-intensive *** yields performance improvement but also involves two atomic locks for *** locks are practically inefficient and become a new performance *** paper proposes a separation technique to partially eliminate atomic protections,termed as Lightweight Forward Push.A Forward Pull solution is further devised to support lock-free PPR computations but also causes useless *** best performance,a new Hybrid Framework is then designed to adaptively balance locking costs and reading costs.

关键词： PageRank GPU Push

Finding Communities by Decomposing and Embedding Heterogeneous Information Network

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Journal of Computer Science & Technology 2020年第2期35卷 320-337页

作者： yue Kou De-Rong Shen Dong Li Tie-Zheng Nie ge yu School of Computer Science and Engineering Northeastern UniversityShenyang 110004China

Community discovery is an important task in social network ***,most existing methods for community discovery rely on the topological structure *** methods ignore the rich information available in the content *** order to solve this issue,in this paper,we present a community discovery method based on heterogeneous information network decomposition and *** traditional methods,our method takes into account topology,node content and edge content,which can supply abundant evidence for community ***,an embedding-based similarity evaluation method is proposed,which decomposes the heterogeneous information network into several subnetworks,and extracts their potential deep representation to evaluate the similarities between ***,a bottom-up community discovery algorithm is *** leader nodes selection,initial community generation,and community expansion,communities can be found more ***,some incremental maintenance strategies for the changes of networks are *** conduct experimental studies based on three real-world social *** demonstrate the effectiveness and the efficiency of our proposed *** with the traditional methods,our method improves normalized mutual information(NMI)and the modularity by an average of 12%and 37%respectively.

关键词： community discovery heterogeneous information network decomposition embedding incremental maintenance

A method to determine the shell layout scheme for equipment battlefield damage tests under artillery fire

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Defence Technology（防务技术） 2021年第2期17卷 682-691页

作者： Cai Chen Quan Shi Zhi-feng You Hong-yu ge Fang Zhang Equipment Command and Management Department Army Engineering UniversityShijiazhuang050003China Baicheng Ordnance Test Center of China Baicheng137001China No.32178 Troops of PLA Beijing100012China

In this paper,a new method for determining the shell layout scheme is proposed,which can make the equipment damage data by the battlefield damage test resemble as close as possible the actual combat *** method is based on the analysis of the impact point distribution and effective damage area of *** order to obtain the position of the impact points,an impact point distribution model under artillery fire was ***,in order to obtain the effective damage area of equipment,the concepts of generalized damage area and task-based equipment functional damage probability were demonstrated,and the corresponding calculation model was *** case analysis,the shell layout scheme was effectively obtained,verifying the correctness of the proposed method.

关键词： Battlefield damage test Projectile impact point Effective damage area Functional damage

A Reprocessing Model for Complete Execution of RFID Access Operations on Tag Memory

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Journal of Computer Science & Technology 2012年第1期27卷 213-224页

作者： Wooseok Ryu Bonghee Hong Joonho Kwon ge yu Department of Computer Engineering Pusan National UniversityBusan 609-735Korea Institute of Logistics Information Technology Pusan National UniversityBusan 609-735Korea School of Information Science and Engineering Northeastern UniversityShenyang 110004China

This paper investigates the problem of inconsistent states of radio frequency identification （RFID） tag data caused by incomplete execution of read/write operations during access to RFID tag memory. Passive RFID tags require RF communication to access memory data. This study is motivated by the volatility of RF communication, where instability is caused by intermittent connections and uncertain communication. If a given tag disappears from the communication area of the reader during the reading or writing of tag data, the operation is incomplete, resulting in an inconsistent state of tag data. To avoid this inconsistency, it is necessary to ensure that any operations on tag memory are completed. In this paper, we propose an asynchronous reprocessing model for finalizing any incomplete execution of read/write operations to remove inconsistent states. The basic idea is to resume incomplete operations autonomously by detecting a tag＇s re-observation from any reader. To achieve this, we present a concurrency control mechanism based on continuous query processing that enables the suspended tag operations to be re-executed. The performance study shows that our model improves the number of successful operations considerably in addition to suppressing inconsistent data access completely.

关键词： asynchronous reprocessing concurrency control continuous query RFID tag access operation

Behavior of aqueous stable colloidal nano-C60 aggregates exposed to TX100 micelles under different environmental conditions

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Frontiers of Environmental Science & Engineering 2015年第2期9卷 197-205页

作者： Jing HUO Ye yu Ling ge Bo ZHANG Yiliang HE School of Environmental Science & Engineering Shanghai Jiaotong University Shanghai 200240 China

C60, as one of carbon nanomaterials widely used in various fields, could be released into the water environment thus exerting some potential health risks to human beings. This work examined the behavior of aqueous stable colloidal nano-C60 （nC60） aggregates under different environmental conditions including Polyethylene glycol octylphenol ether （TX100） micelles concentration, pH, and reaction time when exposed to TX100micelles. Results show that the nC60 aggregates became more dispersive and restored the capability of generating the singlet oxygen when exposed to TX100 micelles. With the increase of TX100 concentration, smaller average size of nC60 aggregates was observed in dynamic light scattering （DLS） analysis, the fluorescence intensity of TX100 was more quenched by nC60 aggregates, and the kinetic rate constant of generating the singlet oxygen for nC60 aggregates was improved. The mean size of nC60 aggregates in the presence of TX 100 had no obvious variations when the pH ranged from 4 to 8. The longer reaction time between nCro aggregates and TX100 led to a higher kinetic rate constant of generating the singlet oxygen. Collective data suggest that variations in physicochemical properties of nC60 aggregates are strongly dependent on the surrounding media under different environmental conditions and directly govern nC60＇S transport behavior and potential toxicity.

关键词： Keywords nano-C60 (nC60) aggregates photochemicalreactivity artificial biological membrane