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Fiducial Marker Based on Projective Invariant for Augmented Reality

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Journal of Computer Science & Technology 2007年第6期22卷 890-897页

作者：李玉王涌天刘越 School of Information Science and Technology Beijing Institute of Technology

Fiducial marker based Augmented Reality has many applications. So far the inner pattern of the fiducial marker is always used to encode the markers. Thus a large portion of the fiducial marker image is used for encoding instead of providing corresponding feature points for pose accuracy. This paper presents a novel method which utilizes directly the projective invariant contained in the positional relation of the corresponding feature points to encode the marker. Tile proposed method does not require the region of pattern image for encoding any more and can provide more corresponding feature points so that higher pose accuracy can be achieved easily. Many related approaches such as cumulative distribution function, reprojection verification and robust process are proposed to overcome the problem of sensibility of the projective invariant. Experimental results show that the proposed fiducial marker system is reliable and robust, and can provide higher pose accuracy than that achieved by existing fiducial marker systems.

关键词： Augmented reality fiducial marker pose estimation projective invariant registration

Task assignment for minimizing application completion time using honeybee mating optimization

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Frontiers of Computer Science 2013年第3期7卷 404-415页

作者： Qinma KANG Hong HE School of Information Engineering Shandong University Weihai 264209 China State Key Laboratory of Computer Science Institute of Software Chinese Academy of Sciences Beijing 100190 China

Effective task assignment is essential for achieving high performance in heterogeneous distributed computing systems. This paper proposes a new technique for minimizing the parallel application time cost of task assignment based on the honeybee mating optimization （HBMO） algorithm. The HBMO approach combines the power of simulated annealing, genetic algorithms, and an effective local search heuristic to find the best possible solution to the problem within an acceptable amount of computation time. The performance of the proposed HBMO algorithm is shown by comparing it with three existing task assignment techniques on a large number of randomly generated problem instances. Experimental results indicate that the proposed HBMO algorithm outperforms the competing algorithms.

关键词： heterogeneous distributed computing task assignment task interaction graph honeybee mating optimization meta-heuristics

A Protocol for a Private Set-Operation

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Journal of Computer Science & Technology 2007年第6期22卷 822-829页

作者：李荣花武传坤 State Key Laboratory of Information Securitg Institute of SoftwareChinese Academy of Sciences

A new private set-operation problem is proposed. Suppose there are n parties with each owning a secret set. Let one of them, say P, be the leader, S be P＇s secret set, and t （less than n - 1） be a threshold value. For each element w of S, if w appears more than t times in the rest parties＇ sets, then P learns which parties＇ sets include w, otherwise P cannot know whether w appears in any party＇s set. For this problem, a secure protocol is proposed in the semi-honest model based on semantically secure homomorphic encryption scheme, secure sharing scheme, and the polynomial representation of sets. The protocol only needs constant rounds of communication.

关键词： secure multiparty computation private set-operation secure protocol

Histogram-Based Estimation of Distribution Algorithm:A Competent Method for Continuous Optimization

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Journal of Computer Science & Technology 2008年第1期23卷 35-43页

作者：丁楠周树德孙增圻 Department of Electronic Engineering Tsinghua University Department of Computer Science and Technology Tsinghua University

Designing efficient estimation of distribution algorithms for optimizing complex continuous problems is still a challenging task. This paper utilizes histogram probabilistic model to describe the distribution of population and to generate promising solutions. The advantage of histogram model, its intrinsic multimodality, makes it proper to describe the solution distribution of complex and multimodal continuous problems. To make histogram model more efficiently explore and exploit the search space, several strategies are brought into the algorithms： the surrounding effect reduces the population size in estimating the model with a certain number of the bins and the shrinking strategy guarantees the accuracy of optimal solutions. Furthermore, this paper shows that histogram-based EDA （Estimation of distribution algorithm） can give comparable or even much better performance than those predominant EDAs based on Gaussian models.

关键词： evolutionary algorithm estimation of distribution algorithm histogram probabilistic model surrounding effect shrinking strategy

Double Barrier Coverage in Dense Sensor Networks

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Journal of Computer Science & Technology 2008年第1期23卷 154-164,F0003页

作者：蒋承东陈国良 Department of Computer Science and Technology University of Science and Technology of China

When a sensor network is deployed to detect objects penetrating a protected region, it is not necessary to have every point in the deployment region covered by a sensor. It is enough if the penetrating objects are detected at some point in their trajectory. If a sensor network guarantees that every penetrating object will be detected by two distinct sensors at the same time somewhere in this area, we say that the network provides double barrier coverage （DBC）. In this paper, we propose a new planar structure of Sparse Delaunay Triangulation （SparseDT）, and prove some elaborate attributes of it. We develop theoretical foundations for double barrier coverage, and propose efficient algorithms with NS2 simulator using which one can activate the necessary sensors to guarantee double barrier coverage while the other sensors go to sleep. The upper and lower bounds of number of active nodes are determined, and we show that high-speed target will be detected efficiently with this configuration.

关键词： wireless sensor network barrier coverage Delaunay triangulation distributed algorithm

DDFS spurious signals due to amplitude quantization in absence of phase-accumulator truncation

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Journal of Systems Engineering and Electronics 2009年第3期20卷 485-492页

作者： Tian Xinguang Liu Xin Chen Hong Duan Miyi Inst. of Computing Technology Beijing Jiaotong Univ. Beijing 100029 P. R. China Inst. of Computing Technology Chinese Academy of Sciences Beijing 100080 P. R. China

Spurious signals in direct digital frequency synthesizers （DDFSs） are partly caused by amplitude quantization and phase truncation, which affect their application to many wireless telecommunication systems. These signals are deterministic and periodic in the time domain, so they appear as line spectra in the frequency domain. Two types of spurious signals due to amplitude quantization are exactly formulated and compared in the time and frequency domains respectively. Then the frequency spectra and power levels of the spurious signals due to amplitude quantization in the absence of phase-accumulator truncation are emphatically analyzed, and the effects of the DDFS parameter variations on the spurious signals are thoroughly studied by computer simulation. And several important conclusions are derived which can provide theoretical support for parameter choice and spurious performance evaluation in the application of DDFSs.

关键词： spurious signal direct digital frequency synthesizer amplitude quantization phase truncation power level.

Query Performance Prediction for Information Retrieval Based on Covering Topic Score

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Journal of Computer Science & Technology 2008年第4期23卷 590-601页

作者：郎皓王斌 Gareth Jones 李锦涛丁凡刘宜轩 Institute of Computing Technology Chinese Academy of Sciences School of Computing Dublin City University

We present a statistical method called Covering Topic Score （CTS） to predict query performance for information retrieval. Estimation is based on how well the topic of a user＇s query is covered by documents retrieved from a certain retrieval system. Our approach is conceptually simple and intuitive, and can be easily extended to incorporate features beyond bag- of-words such as phrases and proximity of terms. Experiments demonstrate that CTS significantly correlates with query performance in a variety of TREC test collections, and in particular CTS gains more prediction power benefiting from features of phrases and proximity of terms. We compare CTS with previous state-of-the-art methods for query performance prediction including clarity score and robustness score. Our experimental results show that CTS consistently performs better than, or at least as well as, these other methods. In addition to its high effectiveness, CTS is also shown to have very low computational complexity, meaning that it can be practical for real applications.

关键词： information storage and retrieval information search and retrieval query performance prediction coveringtopic score

Quasi-Physical Algorithm of an Off-Lattice Model for Protein Folding Problem

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Journal of Computer Science & Technology 2007年第4期22卷 569-574页

作者：刘景发黄文奇 Computer and Software Institute Nanjing University of Information Science and Technology School of Computer Science and Technology Huazhong University of Science and Technology

Protein folding problem is one of the most prominent problems of bioinformatics. In this paper, we study a three-dimensional off-lattice protein AB model with two species of monomers, hydrophobic and hydrophilic, and present a heuristic quasi-physical algorithm. By elaborately simulating the movement of the smooth elastic balls in the physical world, the algorithm finds low-energy configurations for a given monomer chain. A subsequent ＂off-trap＂ strategy is proposed to trigger a jump for a stuck situation in order to get out of local minima. The methods have been tested in the off-lattice AB model. The computational results show promising performance. For all sequences with 13 to 55 monomers, the algorithm finds states with lower energy than previously proposed putative ground states. Furthermore, for the sequences with 21, 34 and 55 monomers, new putative ground states are found, which are different from those given in present literature.

关键词： protein folding off-lattice model quasi-physical algorithm off-trap strategy NP-hard problem

research on Next-Generation Internet Architecture

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Journal of Computer Science & Technology 2006年第5期21卷 723-731页

作者：吴建平徐恪 Department of Computer Science Tsinghua University Beijing 100084 P.R. China

The primary problem during the evolvement of next-generation Internet is the contradiction between growing requirements for Internet and the insufficient development of network theory and technology. As the fundamental principles to guide the developing direction of Internet, the study of Internet architecture is always a focus in the research community. To address the core issue of network scalability, we propose multi-dimension scalable architecture of next-generation Internet, the main idea of which is to extend the single-dimension scalability of traditional Internet on interconnection to multi-dimension scalability of next-generation Internet. The multi-dimension scalability is composed of scale-scalability, performance-scalability, security-scalability, function-scalability, and service-scalability. We suggest five elements, namely, IPv6, authentic IPv6 addressing, scalable processing capacity of routers, end-to-end connectionless Quality-of-Service control, and 4over6 mechanism to realize the multi-dimension scalability. The current research results show that the multi-dimension scalable architecture composed of these five elements will bring great influence on next-generation Internet.

关键词： next-generation Internet multi-dimension scalability IPv6 authentic IPv6 addressing 4over6