Boosting Search with Variable Elimination in Constraint Optimization and Constraint Satisfaction Problems

There are two main solving schemas for constraint satisfaction and optimization problems: i) search, whose basic step is branching over the values of a variables, and ii) dynamic programming, whose basic step is variable elimination. Variable elimination is time and space exponential in a graph parameter called induced width, which renders the approach infeasible for many problem classes. However, by restricting variable elimination so that only low arity constraints are processed and recorded, it can be effectively combined with search, because the elimination of variables may reduce drastically the search tree size.In this paper we introduce BE-BB(k), a hybrid general algorithm that combines search and variable elimination. The parameter k controls the tradeoff between the two strategies. The algorithm is space exponential in k. Regarding time, we show that its complexity is bounded by k and a structural parameter from the constraint graph. We provide experimental evidence that the hybrid algorithm can outperform state-of-the-art algorithms in constraint satisfaction, Max-CSP and Weighted CSP. Especially in optimization tasks, the advantage of our approach over plain search can be overwhelming.     

Banach空间一阶周期边值问题的混合单调方法

研究Banach空间中一阶周期边值微分方程解的存在性。对适合混合单调过程的一类函数，利用上下解的混合单调方法证明了解的存在性，推广了已有的结果[4]。     

黄牛皮劳保鞋面革的制作要点

论述了黄牛皮劳保鞋面革的制作要点。     

从美、英两国的电信资费管制看我国现行电信资费管制的不足

文章介绍了美、英两国在电信资费管制制度的发展历程，阐述了美、英两国在现行的资费管制制度一价格上限制度并从美、英两国的资费管制经验中发现我国现行资费管制制度存在的不足之处，加以改进。     

厚松散层下近风化带保水采煤的GIS研究

煤炭和水都是人类生存和发展的宝贵资源．兖州矿区厚松散层下近风化带的煤炭开采一方面受到第四系下组水的威胁，同时还涉及到第四系下组水资源的合理保护问题。本以兖州市杨庄矿为例，建立了GIS数据库和图形库，通过GIS多因素拟合建立了近风化带覆岩采动破坏“两带”高度的预计模型，提出了考虑保护层的开采上限GIS决策模式，用于保水条件下的安全煤柱留设设计。     

玻纤对二灰碎石基层的力学性能影响试验

玻璃纤维掺入到二灰碎石基层中，对其强度和刚度进行试验。结果表明，掺量一定时，玻纤可提高二灰碎石半刚性基层的强度，随着玻纤掺量的增加．其刚度则有所降低。另外，玻璃纤维还可有效改善二灰碎石基层的韧性。     

恒力弹簧支吊架微机检测系统的研制

探讨了微机检测系统结构、硬、软件设计及系统实施中的关键性技术问题，设计了系统电气测量、控制和通信部分的硬件和软件，分析了系统的可靠性及采取的措施。     

Anomalous Excess Heat Capacities of Ethanol + Alkane Mixtures

A thermodynamic study at atmospheric pressure on the ethanol + n-dodecane and ethanol + n-tridecane binary systems near their liquid-liquid critical points has been carried out. To this end, densities and speeds of sound were determined in the temperature range from 288.15 to 308.15 K, whereas differential scanning calorimetry was used to obtain isobaric heat capacities per unit volume from 288.15 to 303.15 K as well as liquid-liquid equilibrium curves. All these results for the mentioned properties were obtained over the complete composition range. They were used to obtain molar volumes, isentropic compressibilities, isobaric thermal expansivities, isothermal compressibilities, isochoric heat capacities, and the excess quantities of all these properties. An untypical behavior of the excess heat capacities at the lowest measuring temperatures resulting from the critical behavior of the isobaric heat capacity is observed. No clear anomalies for the excess volumetric properties are detected.     

大兴安岭地区初霜冻成因及预报

霜冻的出现一般都是范围广、危害性强、损失大，特别是大兴安岭区地处高纬度地区，初霜来得比较早，对初霜冻的预报就显得格外重要。选取了该区近35a出现初霜的资料，经过分析研究发现，初霜冻的出现和高空环流形势及地面的天空状况有直接的关系。     

Theoretical method for estimation of mean pressure on contact area between rolling tools and workpiece in cross wedge rolling processes

The paper gives a new method no determine the mean unit contact pressures on a material—tool contact surface in cross wedge rolling processes (CWR). The dependencies worked out on the basis of the energy and the upper bound methods permits rolling forces to be determined which are comparable to experimentally measured ones. The analysis provides equations which relate the mean contact pressure q_m to the basic process parameters, namely the forming angle α, the spreading angle β, the relative reduction of a portion δ and the shear friction factors m and m_k.