The Epigenesis of Meaning in Human Beings,and Possibly in Robots

Minds and Machines - This article addresses a classical question: Can a machine use language meaningfully and if so, how can this be achieved? The first part of the paper is mainly philosophical....     

基于DNS的异地服务器负载平衡

随着网络的发展,大型网站的访问量剧增,单台服务器已不能满足需要,负载平衡是解决这一问题的有效方式。分析现有的负载平衡方法,提出一种基于DNS的异地服务器负载平衡新方法。该方法通过控制域名解析,将负载分配到各地服务器,其优点在于既可分散各服务器的负载,增强系统的稳定性,又可利用服务器分放各地的网络环境优势,缩短用户和服务之间通信时间,提高服务质量,从而克服现有负载平衡方法的不足。     

银证联网系统的方案与实现

根据银行业务零售业务部门的总体要求,确定了银证联网的系统方案,具体实施过程中,选取了有关业务的中间件,结合银行、证券两端开发的程序,完成了银证联网的业务需求,最后就银证联网安全性这一敏感问题,进行分析和诊断,并提出措施。     

射击仿真舱液压控制系统设计

介绍了利用单片机对射击仿真舱的液压控制系统进行仿真控制的设计方法,给出了液压系统的设计方案和对射击舱仿真控制控制的程序设计。     

A reactive GRASP and path relinking for a combined production–distribution problem

An NP-hard production–distribution problem for one product over a multi-period horizon is investigated. The aim is to minimize total cost taking production setups, inventory levels and distribution into account. An integer linear model is proposed as a compact problem specification but it cannot be solved to optimality for large instances. Instead of using a classical two-phase approach (production planning and then route construction for each day), metaheuristics that simultaneously tackle production and routing decisions are developed: a GRASP (greedy randomized adaptive search procedure) and two improved versions using either a reactive mechanism or a path-relinking process. These algorithms are evaluated on 90 randomly generated instances with 50, 100 and 200 customers and 20 periods. The results confirm the interest of integrating production and distribution decisions, compared to classical two-phase methods. Moreover, reaction and path-relinking give better results than the GRASP alone.     

“操作系统”课程教学实践环节思考

本文是教授"操作系统"课的心得体会。提出了对"操作系统"课程的一些思考以及对教材改革的思路,并且指出了传统的"操作系统"课程教学环节的弊端和实践环节在"操作系统"这门课中的重要性以及实践环节的多样性,最后指出要从培养高水平的创新性人才出发,研究教材改革的方向和思路。     

Limitations of nonlinear discrete periodic control for disturbance attenuation and robust stabilization

This paper presents a performance analysis of nonlinear periodically time-varying discrete controllers acting upon a linear time-invariant discrete plant. Time-invariant controllers are distinguished from strictly periodically time-varying controllers. For a given nonlinear periodic controller, a time-invariant controller is constructed. Necessary and sufficient conditions are given under which the time-invariant controller gives strictly better control performance than the time-invariant controller from which it was obtained, for the attenuation of l_p exogenous disturbances and the robust stabilization of l_p unstructured perturbations, for all p[1,∞].     

On the bounded-real and positive-real conditions for affine nonlinear state-delayed systems and applications to stability

In this paper, bounded-real conditions for affine nonlinear state-delayed systems are derived using the concept of dissipativeness. Necessary and sufficient conditions for the system to be dissipative and to have finite L₂-gain also referred to as the bounded-real condition are given. The implications on the stability of the system and feedback interconnections of such systems are also considered. Finally, an equivalent of the positive-real lemma is derived and its implications on stability of the system and feedback interconnections of such systems are similarly discussed.     

A method of predicting the number of clusters using Rand's statistic

Distributional and asymptotic results on the moment of Rand's C_k statistic were derived by DuBien and Warde [1981. Some distributional results concerning a comparative statistic used in cluster analysis. ASA Proceedings of the Social Statistics Section, 309–313.]. Based on those results, a method to predict the number of clusters is suggested by applying various agglomerative clustering algorithms. In the procedure, the methods using different indexes are examined and compared based on the concept of agreement (or, disagreement) between clusterings generated by different clustering algorithms on the set of data. Our method having practical generality works better than the other methods and assigns statistical meaning to C_k values in determining the number of clusters from the comparison.     

How causal knowledge simplifies decision-making

Making decisions can be hard, but it can also be facilitated. Simple heuristics are fast and frugal but nevertheless fairly accurate decision rules that people can use to compensate for their limitations in computational capacity, time, and knowledge when they make decisions [Gigerenzer, G., Todd, P. M., & the ABC Research Group (1999). Simple Heuristics That Make Us Smart. New York: Oxford University Press.]. These heuristics are effective to the extent that they can exploit the structure of information in the environment in which they operate. Specifically, they require knowledge about the predictive value of probabilistic cues. However, it is often difficult to keep track of all the available cues in the environment and how they relate to any relevant criterion. This problem becomes even more critical if compound cues are considered. We submit that knowledge about the causal structure of the environment helps decision makers focus on a manageable subset of cues, thus effectively reducing the potential computational complexity inherent in even relatively simple decision-making tasks. We review experimental evidence that tested this hypothesis and report the results of a simulation study. We conclude that causal knowledge can act as a meta-cue for identifying highly valid cues, either individual or compound, and helps in the estimation of their validities.