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Malting multiple views self-maintainable in a data warehouse

DATA & KNOWLEDGE ENGINEERING 1999年第2期30卷 121-134页

作者： Liang, WF Li, H Wang, H Orlowska, ME Univ Queensland CRC Distributed Syst Technol St Lucia Qld 4072 Australia Australian Natl Univ Dept Comp Sci Canberra ACT 0200 Australia Univ Queensland Dept Comp Sci & Elect Engn St Lucia Qld 4072 Australia

A data warehouse collects and maintains a large amount of data from several distributed and heterogeneous data sources. Often the data is stored in the form of materialized views in order to provide fast access to the integrated data, regardless of the availability of the data sources. In this paper we focus on the following problem: for a given set of materialized select-project-join (SPJ) views, how can we find and minimize the auxiliary data stored in a data warehouse in order to make all materialized views in the data warehouse self-maintainable? For this problem we first devise an algorithm for finding such an auxiliary view set by exploiting information sharing among the auxiliary views and materialized views themselves to reduce the total size of auxiliary views. We then consider how to make the data warehouse still self-maintainable by minor modifications when there is a view addition to or deletion from it by giving an algorithm for this incremental maintenance purpose. (C) 1999 Elsevier Science B.V. All rights reserved.

关键词： multiple materialized view maintenance self-maintainability data warehousing data integration algorithm design

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Matching and multidimensional matching in chordal and strongly chordal graphs

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DISCRETE APPLIED MATHEMATICS 1998年第1-3期84卷 79-91页

作者： Dahlhaus, E Karpinski, M Univ Bonn Dept Comp Sci D-53117 Bonn Germany Univ Cologne Dept Math D-50931 Koln Germany Univ Cologne Dept Comp Sci D-50931 Koln Germany

Chordal graphs are graphs with the property that each cycle of length greater than 3 has two non-consecutive vertices that are joined by an edge. An important subclass of chordal graphs are strongly chordal graphs (Farber, 1983). Chordal graphs appear for example in the design of acyclic data base schemes (Beeri et al., 1983). In this paper we study the computational complexity (both sequential and parallel) of the maximum matching problem for chordal and strongly chordal graphs. We show that there is a linear-time greedy algorithm for a maximum matching in a strongly chordal graph provided a strongly perfect elimination ordering is known. This algorithm can also be turned into a parallel algorithm. The technique used can also be extended to the perfect multidimensional matching for chordal and strongly chordal graphs yielding the first polynomial time algorithms for these classes of graphs (the multidimensional matching is NP-complete in general). (C) 1998 Elsevier Science B.V. All rights reserved.

关键词： algorithm design parallel algorithms graph algorithms

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GLONASS Broadcast Orbit Computation

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GPS SOLUTIONS 1998年第2期2卷 16-27页

作者： Stewart, Mike Tsakiri, Maria Curtin Univ Technol Sch Spatial Sci GPO Box U 1987 Perth WA 6845 Australia

The potential 48-satellite constellation offered by the combination of observations from both the GPS and GLONASS positioning systems has created considerable interest among existing GPS users. In the published literature, a considerable amount of work has been devoted to the theoretical issue of algorithm design for combined GPS/GLONASS positioning solutions. Little work has been published, however, on the practical conversion of existing GPS software to include GLONASS observations. This paper considers the computation issues pertaining to the GLONASS broadcast ephemeris for inclusion of GLONASS observations into existing GPS software. The format of the GLONASS broadcast ephemeris is discussed and theory of satellite orbits and their stepwise numerical integration is reviewed. Finally, a strategy for GLONASS broadcast ephemeris computation is proposed to facilitate combination of GPS and GLONASS observations. (c) 1998 John Wiley & Sons, Inc.

关键词： algorithm design Satellite Orbit Theoretical Issue Computation Issue Broadcast Orbit

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Power Efficient, FPGA Implementations of Transform algorithms for Radar-Based Digital Receiver Applications

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IEEE TRANSACTIONS ON INDUSTRIAL INFORMATICS 2013年第3期9卷 1591-1600页

作者： McKeown, Stephen Woods, Roger Queens Univ Belfast Belfast BT3 9DT Antrim North Ireland Queens Univ Belfast Inst Elect Commun & Informat Technol ECIT Belfast BT3 9DT Antrim North Ireland

A key challenge in defense and security systems is to implement functionality within a power budget. We show how data bandwidth redundancy and the need to change performance is exploited to achieve power efficient, field programmable gate array realizations with improved sampling rates. A unified methodology is given for the implementation of a key function, the fast Fourier transform, for a Radar-based digital receiver. Locality of data, temporal and spatial resource usage are examined from first principles, leading to an algorithmic approach that demonstrates substantial industrial benefits in terms of power, performance and resource usage. A power saving of 18% is achieved over a Cooley Tukey design with a 100% speed improvement;the work is extended to other cyclical fast algorithms.

关键词： algorithm design DSP FFT FPGA locality

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When Crowd Meets Big Video Data: Cloud-Edge Collaborative Transcoding for Personal Livecast

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IEEE TRANSACTIONS ON NETWORK SCIENCE AND ENGINEERING 2020年第1期7卷 42-53页

作者： Zhu, Yifei He, Qiyun Liu, Jiangchuan Li, Bo Hu, Yueming Simon Fraser Univ Sch Comp Sci Burnaby BC V5A 1S6 Canada Tableau Software Vancouver BC V6C 3E8 Canada Hong Kong Univ Sci & Technol Dept Comp Sci & Engn Hong Kong Peoples R China South China Agr Univ Coll Nat Resources & Environm Guangzhou 510640 Peoples R China

Deep penetration of personal computing devices and high-speed Internet has enabled everyone to be a broadcaster. In this crowdsourced live streaming service, numerous amateur broadcasters lively stream their video contents to viewers around the world. Consequently, these broadcasters generate a massive amount of video data. The set of video sources and recipients are big as well, so are demand for the storage and computational resources. Transcoding becomes a must to better service these viewers with different network and device configurations. However, the massive amount of video data contributed by countless channels even makes cloud significantly expensive for providing transcoding services to the whole community. In this paper, inspired by the paradigm of Edge Computing, we propose a Cloud-edge collaborative system which combines the idle end-viewers' resources with the cloud to transcode the massive amount of videos at scale. Specifically, we put forward tailored viewer selection algorithms after empirically analyses the viewer behavior data. In the meantime, we propose auction-based payment schemes to motivate these viewers participating in the transcoding. Large-scale trace-driven simulations demonstrate the superiority of our approach in cost reduction and service stability. We further implement a prototype in PlanetLab to prove the feasibility of our design.

关键词： Cloud computing edge computing video transcoding algorithm design

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Joint Flow Routing and DoF Allocation in Multihop MIMO Networks

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IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 2016年第3期15卷 1907-1922页

作者： Qin, Xiaoqi Yuan, Xu Shi, Yi Hou, Y. Thomas Lou, Wenjing Midkiff, Scott F. Virginia Polytech Inst & State Univ Blacksburg VA 24061 USA Intelligent Automat Inc Rockville MD 20855 USA

Recently, degree-of-freedom (DoF)-based models have been widely used to study MIMO network performance. Existing DoF-based models differ in their interference cancellation (IC) behavior and many of them suffer from either loss of solution space or possible infeasible solutions. To overcome these limitations, a new DoF-based model, which employs an IC scheme based on node-ordering was proposed. In this paper, we apply this new DoF IC model to study a throughput maximization problem in a multihop MIMO network. The problem formulation involves joint consideration of flow routing and DoF allocation and falls in the form of a mixed-integer linear program (MILP). Our main contribution is an efficient polynomial time algorithm that offers a competitive solution to the MILP through a series of linear programs (LPs). The algorithm employs a sequential fixing framework to obtain an initial feasible solution and then improves the solution by exploiting: 1) the impact of node ordering on DoF consumption for IC at a node and 2) route diversity in the network. Simulation results show that the solutions obtained by our proposed algorithm are competitive and feasible.

关键词： Network throughput optimization algorithm design multi-hop MIMO networks

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Dynamical modeling of uncertain interaction-based genomic networks

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BMC BIOINFORMATICS 2015年第13-Sup期16卷 1-12页

作者： Mohsenizadeh, Daniel N. Hua, Jianping Bittner, Michael Dougherty, Edward R. Texas A&M Univ Dept Stat College Stn TX 77843 USA Texas A&M Univ Dept Elect & Comp Engn College Stn TX 77843 USA Texas A&M Univ Ctr Bioinformat & Genom Syst Engn College Stn TX 77843 USA

Background: Most dynamical models for genomic networks are built upon two current methodologies, one process-based and the other based on Boolean-type networks. Both are problematic when it comes to experimental design purposes in the laboratory. The first approach requires a comprehensive knowledge of the parameters involved in all biological processes a priori, whereas the results from the second method may not have a biological correspondence and thus cannot be tested in the laboratory. Moreover, the current methods cannot readily utilize existing curated knowledge databases and do not consider uncertainty in the knowledge. Therefore, a new methodology is needed that can generate a dynamical model based on available biological data, assuming uncertainty, while the results from experimental design can be examined in the laboratory. Results: We propose a new methodology for dynamical modeling of genomic networks that can utilize the interaction knowledge provided in public databases. The model assigns discrete states for physical entities, sets priorities among interactions based on information provided in the database, and updates each interaction based on associated node states. Whenever uncertainty in dynamics arises, it explores all possible outcomes. By using the proposed model, biologists can study regulation networks that are too complex for manual analysis. Conclusions: The proposed approach can be effectively used for constructing dynamical models of interaction-based genomic networks without requiring a complete knowledge of all parameters affecting the network dynamics, and thus based on a small set of available data.

关键词： Dynamical model Uncertain networks algorithm design

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Scalable Suffix Sorting on a Multicore Machine

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IEEE TRANSACTIONS ON COMPUTERS 2020年第9期69卷 1364-1375页

作者： Xie, Jing Yi Nong, Ge Lao, Bin Xu, Wentao Sun Yat Sen Univ Sch Data & Comp Sci Guangzhou 510275 Guangdong Peoples R China Guangdong Univ Foreign Studies Sch Informat Sci & Technol Guangzhou 510420 Peoples R China

A number of methods have been proposed for suffix sorting on internal memory of RAM and external memory of hard disks. The current best results for suffix sorting on internal or external memory are achieved by several algorithms using the induced sorting (IS) method in various ways. While these algorithms are efficient, the internal ones are much different from those external in terms of the algorithm designs. A scalable IS method that can be applied for suffix sorting on both internal and external memory is highly desired. This article proposes a blockwise IS method to facilitate pipelined access on internal memory and sequential I/Os on external memory. The detailed algorithm of using this method for a 4-stage pipeline with multiple threads is described, where multiple threads are applied to parallelize not only the pipelined stages of consecutive blocks but also the tasks within each stage wherever possible. This algorithm is evaluated by our experiments on a set of realistic and artificial datasets to achieve better overall time and space performance than the existing best results from pSACAK, pDSS and pKS. Beside sorting suffixes on internal memory in linear time, the proposed method can be ported to external memory for sorting massive suffixes in linear I/O complexity.

关键词： Sorting Random access memory Indexes Multicore processing Arrays Task analysis Big Data Suffix sorting algorithm design multicore computer

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A comparative study of three evolutionary algorithms incorporating different amounts of domain knowledge for node covering problem

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IEEE TRANSACTIONS ON SYSTEMS MAN AND CYBERNETICS PART C-APPLICATIONS AND REVIEWS 2005年第2期35卷 266-271页

作者： He, J Yao, X Li, J Univ Birmingham Sch Comp Sci Ctr Excellence Res Computat Intelligence & Applic Birmingham B15 2TT W Midlands England

This paper compares three different evolutionary algorithms for solving the node covering problem: EA-I relies on the definition of the problem only without using any domain knowledge, while EA-II and EA-III employ extra heuristic knowledge. In theory, it is proven that all three algorithms can find an optimal solution in finite generations and find a feasible solution efficiently;but none of them can find the optimal solution efficiently for all instances of the problem. Through experiments, it is observed that all three algorithms can find a feasible solution efficiently, and the algorithms with extra heuristic knowledge can find better approximation solutions, but none of them can find the optimal solution to the first instance efficiently. This paper shows that heuristic knowledge is helpful for evolutionary algorithms to find good approximation solutions, but it contributes little to search for the optimal solution in some instances.

关键词： algorithm design heuristic knowledge optimization methods performance analysis

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Stable and efficient collision detection scheme for hip-surgery training system

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CLUSTER COMPUTING-THE JOURNAL OF NETWORKS SOFTWARE TOOLS AND APPLICATIONS 2019年第4-Sup期22卷 S8769-S8781页

作者： Wang, Monan Mao, Zhiyong Ma, Yuzheng Cao, Jiaqi Harbin Univ Sci & Technol Mech & Power Engn Coll Harbin Heilongjiang Peoples R China

To satisfy real-time requirements, collision detection algorithms should be stable and efficient, and should be capable of accurate detection. This paper presents a collision detection algorithm that is based on the concept of dimension reduction of imitating latitude and longitude space. We achieve a rough and accurate detection function of the algorithm after four steps including latitude detection, bounding box detection, crossing-algorithm detection, and an affine coordinate system for accurate detection. The efficiency of the proposed collision detection algorithm is higher than that of the aligned axis bounding box (AABB) collision detection algorithm in terms of both rough detection and accurate detection. The efficiencies of coarse detection and accurate detection are basically the same, and the efficiencies of both types of detection are stable. The proposed collision detection algorithm has good stability, high efficiency, and accurate detection, and it can be used as the core algorithm of a collision detection module in virtual surgery training systems.

关键词： Virtual surgery training Collision detection algorithm design Imitating latitude and longitude Spatial dimensional reduction

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