On the optimal design of fuzzy neural networks with robust learningfor function approximation

A novel robust learning algorithm for optimizing fuzzy neural networks is proposed to address two important issues: how to reduce the outlier effects and how to optimize fuzzy neural networks, in the function approximation. This algorithm is able to reduce the outlier effects by cooperating with a conventional robust approach, and then to optimize fuzzy neural networks by determining the optimal learning rates which can minimize the next-step mean error at each iteration of our algorithm.     

Optimizing multiple dimensional queries simultaneously in multidimensional databases

Some significant progress related to multidimensional data analysis has been achieved in the past few years, including the design of fast algorithms for computing datacubes, selecting some precomputed group-bys to materialize, and designing efficient storage structures for multidimensional data. However, little work has been carried out on multidimensional query optimization issues. Particularly the response time (or evaluation cost) for answering several related dimensional queries simultaneously is crucial to the OLAP applications. Recently, Zhao et al. first exploited this problem by presenting three heuristic algorithms. In this paper we first consider in detail two cases of the problem in which all the queries are either hash-based star joins or index-based star joins only. In the case of the hash-based star join, we devise a polynomial approximation algorithm which delivers a plan whose evaluation cost is $ O(n^{\epsilon }$) times the optimal, where n is the number of queries and is a fixed constant with . We also present an exponential algorithm which delivers a plan with the optimal evaluation cost. In the case of the index-based star join, we present a heuristic algorithm which delivers a plan whose evaluation cost is n times the optimal, and an exponential algorithm which delivers a plan with the optimal evaluation cost. We then consider a general case in which both hash-based star-join and index-based star-join queries are included. For this case, we give a possible improvement on the work of Zhao et al., based on an analysis of their solutions. We also develop another heuristic and an exact algorithm for the problem. We finally conduct a performance study by implementing our algorithms. The experimental results demonstrate that the solutions delivered for the restricted cases are always within two times of the optimal, which confirms our theoretical upper bounds. Actually these experiments produce much better results than our theoretical estimates. To the best of our knowledge, this is the only development of polynomial algorithms for the first two cases which are able to deliver plans with deterministic performance guarantees in terms of the qualities of the plans generated. The previous approaches including that of [ZDNS98] may generate a feasible plan for the problem in these two cases, but they do not provide any performance guarantee, i.e., the plans generated by their algorithms can be arbitrarily far from the optimal one. Received: July 21, 1998 / Accepted: August 26, 1999     

遗传算法求解邮递员问题的探讨

邮递员问题是目前一个尚未完全解决的图论问题,而遗传算法则是一个比较好的全局搜索算法,本文提出了一种换方法,以此为基础,用遗传算法实现了对有向图邮递员问题的求解,较传统方法更加容易实现,在求解大规模复杂网络时,其效率更高。     

Influence of gas flow through the vibrating grid on the hydrodynamics of a shallow vibrofluidized bed

The dependence of the characteristics of vibrofluidization on the coefficients of hydraulic resistance of the bed and the grid and on a steady pressure drop (or gas flow) imposed from outside is analyzed.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 34, No. 4, pp. 604–613, April, 1978.     

Equation of state of the liquid alkali metals. I.

Experimental PVT data are given for sodium, rubidium, and cesium in the liquid phase. Procedures and measurement errors are discussed.Notation P pressure - V volume - T temperature - density - R solubility - D coefficient of diffusion - t time - L diffusion length - thermal expansion - C_p isobaric specific heat Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 35, No. 5, pp. 901–907, November, 1978.