国家自然科学基金科学传播体系构建研究

经过25年的发展,国家自然科学基金现已成为国家知识创新体系的重要组成部分,为我国在基础科学多个领域赶超世界先进水平提供了强有力保障,支撑着我国社会科学事业的持续创新发展。通过不断探索与实践,积累了丰富的科学基金管理经验,形成了具有中国特色的科学基金管理制度。通过国家自然科学基金的资助,由项目申报到结题过程中形成的成果、人才、平台等信息,构成了一个庞大的科学信息库。国家自然科学基金的科学传播应以政府管理层、科学家群体、社会公众对科学基金信息的诉求为出发点;运用现代科学传播方法和不同传播媒介,有效构建新型的科学传播体系,以科技新闻报道为主体,多种科学传播形式综合运用,向社会广为传播;在营造科技创新的社会环境、促进社会科学事业的加速发展。同时,使政府、科技界和全社会对科学基金工作有一个全面的认识,推动科学基金未来更好地发展;自然科学基金科学传播应遵循针对性原则、客观性原则、时效性原则和保密原则;科学传播要注重多种媒体组合宣传和宣传时机及时段,强调"内宣"与"外宣"的有效结合,充分发挥主流媒体和科技媒体的组合传播效果。     

一种ANDSF获取接入网动态信息的方法

下一代异构无线网络环境是宽带移动无线接入和异构分布的网络,如何减少切换时延实现无缝切换是当前需要解决的问题。文章针对在切换之前如何获取有效的接入网信息提出了一种新的方法,即一种ANDSF(接入网发现和选择功能)获取接入网动态信息的方法,该方法可以保证ANDSF中接入网信息及时准确。然后介绍ANDSF功能实体,分析其工作原理,指出其不足,并提出改进方法。     

票信通产品在信息管税工作中的应用探讨

票信通产品是中国联通利用网络优势与税务机关联合推出的一个网络发票服务产品。文章分析网络发票在我国的应用现状,提出平台的技术架构,介绍票信通产品的主要业务功能。并阐述推广此业务的意义。     

Network design problem with relays: A genetic algorithm with a path-based crossover and a set covering formulation

The network design problem with relays arises in telecommunications and distribution systems where the payload must be reprocessed at intermediate stations called relays on the route from its origin to its destination. In fiber-optic networks, for example, optical signals may be regenerated several times to overcome signal degradation because of attenuation and other factors. Given a network and a set of commodities, the network design problem with relays involves selecting network edges, determining a route for each commodity, and locating relays to minimize the network design cost. This paper presents a new formulation to the problem based on set covering constraints. The new formulation is used to design a genetic algorithm with a specialized crossover/mutation operator which generates a feasible path for each commodity, and the locations of relays on these paths are determined by solving the corresponding set covering problem. Computational experiments show that the proposed approach can outperform other approaches, particularly on large size problems.     

Robust ranking and portfolio optimization

The portfolio optimization problem has attracted researchers from many disciplines to resolve the issue of poor out-of-sample performance due to estimation errors in the expected returns. A practical method for portfolio construction is to use assets’ ordering information, expressed in the form of preferences over the stocks, instead of the exact expected returns. Due to the fact that the ranking itself is often described with uncertainty, we introduce a generic robust ranking model and apply it to portfolio optimization. In this problem, there are n objects whose ranking is in a discrete uncertainty set. We want to find a weight vector that maximizes some generic objective function for the worst realization of the ranking. This robust ranking problem is a mixed integer minimax problem and is very difficult to solve in general. To solve this robust ranking problem, we apply the constraint generation method, where constraints are efficiently generated by solving a network flow problem. For empirical tests, we use post-earnings-announcement drifts to obtain ranking uncertainty sets for the stocks in the DJIA index. We demonstrate that our robust portfolios produce smaller risk compared to their non-robust counterparts.     

模糊数学精品课程建设与实践

模糊数学课程是我校各专业研究生的一门重要的公共基础课,实施模糊数学核心课程建设,对于深化教学改革、提高教学质量以及培养研究生的实践能力和创新能力起着极其重要的作用,从模糊数学课程性质、目的和任务人手,较详细地阐述了模糊数学课程的教学内容、体系,教学模式和手段等系列改革以及模糊数学课程建设中取得的显著成效。     

Optimal locating arrays for at most two faults

Locating arrays are of interest in generating software test suites to cover all t-way component interactions and locate interaction faults in component-based systems.Recently,Tang,Colbourn and Yin made an investigation into optimal locating arrays in the case where a single fault is to be located.They pointed out that when two or more faults were considered,matters would become rather complicated.To handle those cases generally seems challenging,but is well worth further research.In this paper,we establish a lower bound on the size of locating arrays with at most two faults,and then prove that optimal locating arrays meeting this bound can be equivalently characterized in terms of orthogonal arrays with prescribed properties.Using this characterization,we develop a number of constructions of optimal locating arrays.Two infinite series of optimal locating arrays are then obtained.     

金华山软岩铁路隧道施工过程围岩屈服接近度分析

隧道施工过程中围岩处于复杂应力状态下,隧道围岩屈服区演化特征的确定对于围岩稳定性分析和开挖支护方案优化具有重要的意义。采用屈服接近度指标衡量围岩破坏接近程度可以合理地描述复杂应力状态下围岩的应力危险性,对Mohr-Coulomb类岩体材料的屈服接近度函数进行了相应的推导,并在非线性有限元用户子程序上编程予以实现。介绍了赣州-龙岩铁路DKl33+095～DKl38+237段软弱围岩单线隧道正台阶步施工方案以及湿喷纤维混凝土支护方案。为了对该隧道施工过程中隧道围岩屈服区的演化特征进行合理评价,采用非线性有限元法对软弱围岩条件下的铁路隧道施工过程进行了数值模拟,分析了施工过程中隧道围岩屈服接近度分布特征,判定了隧道台阶步施工过程中隧道围岩的稳定性。分析结果表明:该隧道施工过程中围岩破坏区主要发生在下台阶步施工过程中;屈服接近度指标比传统的塑性区分布提供的信息更加丰富,有利于工程技术人员定量地评价隧道开挖支护方案。     

基于动力松弛法的松弛索杆体系找形分析

索杆张力结构施工成形分析需要解决一个松弛态索杆系统的平衡形态求解问题,该问题可归结为一个给定构件原长的受荷索杆机构系统的找形问题。文中利用动力松弛法进行该类松弛索杆体系的找形分析。由于不建立刚度矩阵,避免了体系几何不稳定性所引起的刚度矩阵奇异问题。该方法采用悬链线索单元模型,可以考虑索大垂度效应。文中还推导了反映索原长和内力之间关系的悬链线索单元协调方程。通过一个正交松弛索网算例分析,考察了该找形方法的计算精度和收敛性。最后还模拟了一个索穹顶的施工成形过程,表明了该找形方法用于索杆张力结构施工成形分析的有效性。     

河道施工降水引起的邻近建筑物沉降分析

通过对地基进行沉降计算, 对基础沉降进行实际观测, 将计算数值与观测数值进行对比分析. 结果表明: 施工降水是导致邻近建筑物沉降、开裂的原因; 邻近建筑物地基沉降的规律是离 施工降水现场由近至远逐渐减小; 采用设止水帷幕和回灌井联合控制地下水位下降是一种有 效的措施.