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Combining search space partition and Abstraction for LTL model checking

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Science in China(Series F) 2007年第6期50卷 793-810页

作者： PU Fei ZHANG WenHui State Key Laboratory of Computer Science Institute of Software Chinese Academy of Sciences Beijing 100080China School of Computing and Mathematics University of Western Sydney Australia

The state space explosion problem is still the key obstacle for applying model checking to systems of industrial size. Abstraction-based methods have been particularly successful in this regard. This paper presents an approach based on refinement of search space partition and Abstraction which combines these two techniques for reducing the complexity of model checking. The refinement depends on the representation of each portion of search space. Especially, search space can be refined stepwise to get a better reduction. As reported in the case study, the integration of search space partition and Abstraction improves the efficiency of verification with respect to the requirement of memory and obtains significant advantage over the use of each of them in isolation.

关键词： search space partition refinement Abstraction LTL model checking

Reduction and Simplification of Explicit LTL Model Checking via an Abstraction Method

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Tsinghua Science and Technology 2009年第1期14卷 90-94页

作者：孙军波罗贵明 Tsinghua National Laboratory for Information Science and Technology (TNList) School of Software Tsinghua University

An Abstraction method developed for the explicit linear temporal logic model checking was geared towards reducing the useless part of the state space during the Abstraction period. This reduces the cost during the Abstraction period relative to models requiring many useless states. A dining-philosophers example comparing this Abstraction method with conventional methods indicates that a large proportion of the state space has been reduced by this Abstraction method. Finally, the abstract method is shown to be correct and an analysis is given to show how such a large proportion of states can be reduced.

关键词： linear temporal logic explicit model checking Abstraction Buchi automaton

Automatic Abstraction of interference fringes with image technique

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Journal of Harbin Institute of Technology(New Series) 2002年第2期9卷 166-169页

作者：浦昭邦陶卫张敏 Harbin Inst. of Technol. Harbin 150001 China

ion technique of interference fringes used in phase modulation and phase scanning modulation interferometer is presented. For the measurement of amplitudes of interference fringes, fringes are fitted and their central points are determined automatically according to their distribution rules. However, for the measurement of their phases, fringes should be recognized and processed with different calculating algorithms and least square optimization methods depending on the scanning modulation mode. When this technique is used for measurement of surface roughness, the measurement uncertainty is better than 5nm and the repeatability is less than 5%.

关键词： interference fringes Abstraction phase-modulation image detection

Quantum chemical study on insertion and Abstraction reaction of dichlorocarbene with methyl alcohol and methyl mercaptan

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Science China Chemistry 2009年第3期52卷 304-312页

作者： LI ZhiFeng ZHU YuanCheng LI HuiXue LIU XinWen LU XiaoQuan College of Life Science and Chemistry Tianshui Normal UniversityTianshui 741001China Key Laboratory of Polymer Materials of Gansu Province College of Chemistry and Chemical EngineeringNorthwest Normal UniversityLanzhou 730070China

The insertion and Abstraction reaction mechanisms of singlet and triplet CCl2 with CH3MH (M=O, S) have been studied by using the DFT, NBO and AIM methods. The geometries of reactions, the transition state and products were completely optimized by B3LYP/6-311G(d, p). All the energy of the species was obtained at the CCSD(T)/6-311G(d, p) level. The calculated results indicated that the major pathways of the reaction were obtained on the singlet potential energy surface. The singlet CCl2 can not only trigger the insertion reaction with C-H and M-H in four pathways, by which the products P1 [CH3OCHCl2, reactionⅠ(1)], P3[Cl2HCCH2OH, reactionⅠ(2)], P5[CH3SCHCl2, reactionⅡ(1)] and P7[Cl2HCCH2SH, reac-tion Ⅱ(2)] are produced respectively, but also abstract M-H, resulting P4 [CH2O+CH2Cl2, reactionⅠ(3)] and P8[CH2S+CH2Cl2, reactionⅡ(3)]. In addition, the important geometries in domain pathways have been studied by AIM and NBO theories.

关键词： carbene alcohol DFT NBO AIM insertion reaction Abstraction reaction

The Role of Abstraction in the Evolution of Semiotic Systems

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Language and Semiotic Studies 2016年第3期2卷 36-47页

作者： Javier Terrado University of Lleida Spain

The action of signs in human lives and in the evolution of cultures is to be understood in the light of semiosis, the process by which a meaning is given to all things in the world. Writing systems, as a sort of semiotic creation, evolve according to the laws of semiosis and the rhythm of human stepping ahead. This paper is an attempt to afford evidence of three relevant facts: a) A close contact, or at least a remarkable coincidence, of writing cultures in ancient times. b) An apparent and undeniable process of divergence of writing systems over centuries. c) A tendency to a new convergence of writing systems, as an ongoing process inferable from the new symbols of an increasingly globalised world. We propose that one of the elements that push these processes forward is Abstraction, and we suggest that Abstraction might be the leading factor in the evolution of writing and semiotic systems.

关键词： semiotics semiosis Abstraction evolution system history of writing

Multiple Levels of Abstraction in the Simulation of Microthreaded Many-Core Architectures

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Open Journal of Modelling and Simulation 2015年第4期3卷 159-190页

作者： Irfan Uddin Institute of Information Technology Kohat University of Science and Technology Kohat Pakistan

Simulators are generally used during the design of computer architectures. Typically, different simulators with different levels of complexity, speed and accuracy are used. However, for early design space exploration, simulators with less complexity, high simulation speed and reasonable accuracy are desired. It is also required that these simulators have a short development time and that changes in the design require less effort in the implementation in order to perform experiments and see the effects of changes in the design. These simulators are termed high-level simulators in the context of computer architecture. In this paper, we present multiple levels of Abstractions in a high-level simulation of a general-purpose many-core system, where the objective of every level is to improve the accuracy in simulation without significantly affecting the complexity and simulation speed.

关键词： High-Level Simulations Multiple Levels of Abstraction Design Space Exploration Many-Core Systems

Role of hydrogen in the dissociation of CH4 on different graphene by DFT study

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Chinese Journal of Aeronautics 2022年第6期35卷 407-419页

作者： Kun LI Hejun LI Ni LI Qiang SONG Lehua QI State Key Laboratory of Solidification Processing Carbon/Carbon Composites Research CenterNorthwestern Polytechnical UniversityXi’an 710072China School of Aeronautics Northwestern Polytechnical UniversityXi’an 710072China School of Mechanical Engineering Northwestern Polytechnical UniversityXi’an 710072China

The effect of hydrogen on the growth mechanism of pyrocarbon has attracted much attention. The influence of hydrogen on the dissociation from CH4to C2H2on pristine graphene,N-doped graphene and vacancy graphene have been investigated by using density functional theory.There are two kinds of heterogeneous reaction pathways when the hydrogen is involved, i.e., dehydrogenation reactions and H-Abstraction reactions. The transition state calculations were performed to acquire the reaction pathways on each substrate after obtaining the most stable adsorption configurations of the reactants and products. The results indicate that the adsorptions of reactants are not affected by hydrogen. The dehydrogenation reactions are more favored on vacancy graphene, and the H-Abstraction reactions are more favored on the pristine graphene and N-doped graphene. The dehydrogenation reactions on the vacancy graphene are most favored among all these reactions in favor of the deposition of pyrocarbon. The dehydrogenation reactions on these three substrates are affected by hydrogen.

关键词： Abstraction Dehydrogenation DFT Graphene Hydrogen Methane

Density Functional Theory Studies on the Addition and Abstraction Reactions of OH Radical with Benzoate Anion

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Open Journal of Physical Chemistry 2013年第1期3卷 7-13页

作者： Nobuaki Tanaka Shigeo Itoh Department of Environmental Science and Technology Faculty of Engineering Shinshu University Nagano Japan

The addition and Abstraction reactions of OH radical with benzoate anion are investigated by density functional theory calculations that include solvent effects using UB3LYP, UCAM-B3LYP, UmPW1PW91 and UM06-2X functionals with the 6-311++G(2d,2p) basis set. Geometry optimizations of the reactants, products and transition state species are performed for the possible reaction paths. For the addition reactions, those targeting the ipso-, ortho-, meta- and para-carbons are predicted to be exoergic. The H-atom Abstraction reactions from ortho, meta and para positions are also predicted to be exoergic. On the basis of the rate constants calculated by means of the transition state theory, the H-atom Abstraction reaction from the ortho position is determined to be the favored path followed by the ortho OH addition reaction.

关键词： DFT Calculation Benzoate Anion H-Atom Abstraction OH Addition Transition State Theory

Topology Abstraction Service for IP VPNs: Core Network Partitioning for Resource Sharing

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American Journal of Operations Research 2018年第3期8卷 167-202页

作者： Ravishankar Ravindran Changcheng Huang Krishnaiyan Thulasiraman Tachun Lin Huawei Research Center Santa Clara CA USA Carleton University Ottawa Canada University of Oklahoma Norman OK USA Bradley University Peoria IL USA

VPN service providers (VSP) and IP-VPN customers have traditionally maintained service demarcation boundaries between their routing and signaling entities. This has resulted in the VPNs viewing the VSP network as an opaque entity and therefore limiting any meaningful interaction between the VSP and the VPNs. A key challenge is to expose each VPN to information about available network resources through an Abstraction (TA) [1] which is both accurate and fair. In [2] we proposed three decentralized schemes assuming that all the border nodes performing the Abstraction have access to the entire core network topology. This assumption likely leads to over- or under-subscription. In this paper we develop centralized schemes to partition the core network capacities, and assign each partition to a specific VPN for applying the decentralized Abstraction schemes presented in [2]. First, we present two schemes based on the maximum concurrent flow and the maximum multicommodity flow (MMCF) formulations. We then propose approaches to address the fairness concerns that arise when MMCF formulation is used. We present results based on extensive simulations on several topologies, and provide a comparative evaluation of the different schemes in terms of Abstraction efficiency, fairness to VPNs and call performance characteristics achieved.

关键词： IP-VPN Service Topology Abstraction Maximum Concurrent Flow Maximum Multicommodity Flow