Improving probability selection based weights for satisfiability problems

Boolean Satisfiability problem (SAT) plays a prominent role in many domains of computer science and artificial intelligence due to its significant importance in both theory and applications. Algorithms for solving SAT problems can be categorized into two main classes: complete algorithms and incomplete algorithms (typically stochastic local search (SLS) algorithms). SLS algorithms are among the most effective for solving uniform random SAT problems, while hybrid algorithms achieved great breakthroughs for solving hard random SAT (HRS) problem recently. However, there is a lack of algorithms that can effectively solve both uniform random SAT and HRS problems. In this paper, a new SLS algorithm named SelectNTS is proposed aiming at solving both uniform random SAT and HRS problem effectively. SelectNTS is essentially an improved probability selection based local search algorithm, the core of which includes new clause and variable selection heuristics: a new clause weighting scheme and a biased random walk strategy are utilized to select a clause, while a new probability selection strategy with the variation of configuration checking strategy is used to select a variable. Extensive experimental results show that SelectNTS outperforms the state-of-the-art random SAT algorithms and hybrid algorithms in solving both uniform random SAT and HRS problems effectively

An efficient contradiction separation based automated deduction algorithm for enhancing reasoning capability

Automated theorem prover (ATP) for first-order logic (FOL), as a significant inference engine, is one of the hot research areas in the field of knowledge representation and automated reasoning. E prover, as one of the leading ATPs, has made a significant contribution to the development of theorem provers for FOL, particularly equality handling, after more than two decades of development. However, there are still a large number of problems in the TPTP problem library, the benchmark problem library for ATPs, that E has yet to solve. The standard contradiction separation (S-CS) rule is an inference method introduced recently that can handle multiple clauses in a synergized way and has a few distinctive features which complements to the calculus of E. Binary clauses, on the other hand, are widely utilized in the automated deduction process for FOL because they have a minimal number of literals (typically only two literals), few symbols, and high manipulability. As a result, it is feasible to improve a prover's deduction capability by reusing binary clause. In this paper, a binary clause reusing algorithm based on the S-CS rule is firstly proposed, which is then incorporated into E with the objective to enhance E’s performance, resulting in an extended E prover. According to experimental findings, the performance of the extended E prover not only outperforms E itself in a variety of aspects, but also solves 18 problems with rating of 1 in the TPTP library, meaning that none of the existing ATPs are able to resolve them

Effects of Small Amounts of Phosphoric Acid as Additive in the Preparation of Microporous Activated Carbons

The activated carbons with well-developed microporosity were prepared from fir wood (Cunninghamia lanceolata) impregnated with small amounts of phosphoric acid (impregnation ratios, 1.5 – 4.5 wt.%). For comparison purpose, a parallel study of fir wood without impregnation was carried out in the same conditions. The results showed that the addition of small amounts of H3PO4 could lower the thermal decomposition temperature of fir wood and significantly promote the adsorption capacity and the yield of activated carbon. The yield without phosphoric acid impregnation was 6.55 wt.%, which rose to 19.82 wt.% in the case of 3.0 wt.% H3PO4 impregnation. Using small amounts of phosphoric acid as additive was beneficial to improve specific surface area (SBET) and micropore volume (Vmic), and could produce activated carbons with well-developed microporous structure. With 3.0 wt.% H3PO4 impregnation, SBET and Vmic of the activated carbon reached as high as 1281.6 m2/g and 0.535 mL/g, the ratio of Vmic/Vtot (total pore volume) was higher than 80 %. DOI: http://dx.doi.org/10.5755/j01.ms.24.4.18999</p

Graph-Based Node Finding in Big Complex Contextual Social Graphs

Graph pattern matching is to find the subgraphs matching the given pattern graphs. In complex contextual social networks, considering the constraints of social contexts like the social relationships, the social trust, and the social positions, users are interested in the top-K matches of a specific node (denoted as the designated node) based on a pattern graph, rather than the entire set of graph matching. This inspires the conText-Aware Graph pattern-based top-K designated node matching (TAG-K) problem, which is NP-complete. Targeting this challenging problem, we propose a recurrent neural network- (RNN-) based Monte Carlo Tree Search algorithm (RN-MCTS), which automatically balances exploring new possible matches and extending existing matches. The RNN encodes the subgraph and maps it to a policy which is used to guide the MCTS. The experimental results demonstrate that our proposed algorithm outperforms the state-of-the-art methods in terms of both efficiency and effectiveness

Computer vision based calibration of the purely translational Orthopod manipulator

In this paper, we have achieved kinematic calibration of the purely translational Orthopod parallel mechanism via a flexible measuring system, which is based on Costar SI-M350 CCD camera with TEC-M12 lens. We first identify intrinsic parameters of the camera and the camera calibration result is verified using a simple yet practical experiment. Then we perform manipulator calibration using its inverse kinematics model. To evaluate the visionbased kinematic calibration method, we let the endeffector undergo a uniaxial translation and observe its leg parallelism [1]. Experiment data verifies the effectiveness and flexibility of the proposed calibration method.6 page(s

Exponential Submanifolds: A New Kinematic Model For Mechanism Analysis and Synthesis

This paper aims to develop a new kinematic model, the exponential submanifolds (EXPSs) e(Omega) with Omega a subspace of se (3) (the Lie algebra of the special Euclidean group SE(3)), for mechanism analysis and synthesis. The EXPSs provide perfect models for many global motion types appearing in the past mechanisms, robotics and kinesiology literatures which cannot be modeled as the well known Lie subgroups or their product. We derive in this paper both the sufficient and necessary conditions on Omega such that e(Omega) is an EXPS, and geometric properties of the EXPS for mechanism analysis and synthesis

Computing resources market in grid and cloud based on contract management

With the development of information technologies and the popularity of on-line shopping, a special market where people can trade computing resources easily and safely has been focused on recently. The architecture of such a market in economic Grid environment is overall presented and discussed in this paper. Some efficient management mechanisms, including contract constrain, third-party depository service, dynamic reputation evaluation and dynamic price fluctuation, are employed into this market and proved to be important roles in regulating trading activities and keeping the market in healthy operations. Furthermore, the computing resources market in Cloud environment is also proposed and preliminarily discussed in this paper.5 page(s