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Mechanical Assembly Packing problem Using Joint Constraints

Journal of Computer Science & Technology 2017年第6期32卷 1162-1171页

作者： Ming-Liang Xu Ning-Bo Gu Wei-Wei Xu Ming-Yuan Li Jun-Xiao Xue Bing Zhou School of Information Engineering Zhengzhou University Zhengzhou 450000 China State Key Laboratory of Computer Aided Design and Computer Graphics Zhejiang University Hangzhou 310058 China School of Software Zhengzhou University Zhengzhou 450000 China

The three-dimensional packing problem is generally on how to pack a set of models into a given bounding box using the smallest packaging volume. It is known as an np-hard problem. When discussing the packing problem in mechanical field, the space utilization of a mechanism is low due to the constraint of mechanical joints between different mechanical parts. Although such a situation can be improved by breaking the mechanism into components at every joint, it burdens the user when reassembling the mechanism and may also reduce the service life of mechanical parts. In this paper, we propose a novel mechanism packing algorithm that deliberately considers the DOFs （degrees of freedom） of mechanical joints. With this algorithm, we construct the solution space according to each joint. While building the search tree of the splitting scheme, we do not break the joint, but move the joint. Therefore, the algorithm proposed in this paper just requires the minimal number of splits to meet the goal of space utilization. Numerical examples show that the proposed method is convenient and efficient to pack three-dimensional models into a given bounding box with high space utilization.

关键词： np-hard problem packing problem search tree

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A new DNA algorithm to solve graph coloring problem

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Progress in Natural Science:Materials International 2007年第6期17卷 733-738页

作者： Jiang Xingpeng1, Li Yin2, Meng Ya3 and Meng Dazhi2(1. National Laboratory of Pattern Recognition,Institute of Automation, Chinese Academy of Sciences, Beijing 100080, China 2. College of Applied Sciences, Beijing University of Technology, Beijing 100022, China 3. School of Science, Beijing Institute of Technology, Beijing 100081, China) National Laboratory of Pattern Recognition Institute of Automation Chinese Academy of Sciences Beijing 100080 China College of Applied Sciences Beijing University of Technology Beijing 100022 China School of Science Beijing Institute of Technology Beijing 100081 China

Using a small quantity of DNA molecules and little experimental time to solve complex problems successfully is a goal of DNA computing. Some np-hard problems have been solved by DNA computing with lower time complexity than conventional computing. However, this advantage often brings higher space complexity and needs a large number of DNA encoding molecules. One example is graph coloring problem. Current DNA algorithms need exponentially increasing DNA encoding strands with the growing of problem size. Here we propose a new DNA algorithm of graph coloring problem based on the proof of four-color theorem. This algorithm has good properties of needing a relatively small number of operations in polynomial time and needing a small number of DNA encoding molecules (we need only 6R DNA encoding molecules if the number of regions in a graph is R).

关键词： DNA computing np-hard problem graph coloring problem.

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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

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Concepts,measurements and scientific problems of biocomplexity

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Integrative Zoology 2007年第2期2卷 100-110页

作者： Zhibin ZHANG Institute of Zoology Chinese Academy of SciencesBeijingChina

There is increasing awareness of biocomplexity as a field of study,although there are some disagreements about its definition among *** science of biocomplexity has been influenced greatly by the emergence of the science of complexity,which aims to solve complicated problems in complex *** this paper,I review the basic concepts and scientific problems of biocomplexity.I argue that biological systems are adaptive complex systems that tend to become more complicated over time.I hypothesize that complexity is favored by natural *** are two relatively independent evolutionary templates for complexity in biological systems:gene-guided and neural-guided *** general,biology has been overly influenced by gene-dominant evolution theory,which cannot account for the complex behaviors,social structures,and ecosystems that *** energy intake,non-polynomial(np)-hard problems and stability(***,non-linear and evolutionary stability)are probably the three most important properties of biological *** work is not equivalent to the energy input(non-equivalence rule)in biological systems because the input energy is *** total work can be measured using the order energy(ordergy),a function of energy input and the efficiency of energy *** may be essential in solving np-hard problems and in reducing the instability of non-linearity in biological systems.

关键词： biocomplexity energy hierarchy natural selection np-hard problem stability work

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DNA Supercomputing of Multiprocessor’s Independent Task Scheduling problem

DNA Supercomputing of Multiprocessor’s Independent Task Sch...

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2011年全国电子信息技术与应用学术会议

作者： Jianbo WANG Department of Computer Science and Technology Hunan Institute of Humanities,Science and Technology Loudi,China Guangjun GUO,Xinbo CHEN Department of Electric and Electrical Engineering Loudi Vocational and Technical College Loudi,China

Task scheduling is a np-hard problem and is an integral part of parallel and distributed *** this paper,implementation ideas and methods to solve independent task scheduling problem which is an engineering related combinatorial problem using this DNA computing approach is *** objective of solution of the independent task scheduling problem is to find an optimal scheduling that can satisfy with resources load *** proposed algorithms show promising results that DNA computing approach can be well-suited for solving such real-world application in the near future.

关键词： DNA computing task scheduling np-hard problem parallel computing

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