分布式防火墙技术研究

介绍了分布式防火墙的产生、体系结构、主要特点及存在的问题.     

安钢高强板AH60的生产实践

本文论述了高强度低合金钢板AH60的试制过程，结合产品技术要求和生产实际设计合理的成分体系和工艺路线。     

A fuzzy constraint satisfaction approach for electronic shopping assistance

The Internet and World Wide Web offer an additional channel for consumers to find, select, and buy products. However, unlike shopping in the traditional store, consumers have no direct contact with human clerks to get the required information in the electronic store. The objective of this paper is to propose a fuzzy constraint satisfaction approach to help buyers find fully satisfactory or replacement products in electronic shopping. For the buyer who can give precise product requirements, the proposed approach can generate product-ranking lists based on the satisfaction degrees of each product to the given requirements. For the buyer who may not input accurate requirements, a similarity analysis approach is proposed to assess buyer requirements automatically during his browsing process. The proposed approach could help buyers find the preferred products on the top of the ranking list without further searching the remaining pages. The experimental results show the applicability of the proposed approach for electronic shopping assistance.     

The coming of CSP: automated assembly processes for high-volume chip scale packaging

Chip scale packaging (CSP) is emerging as a major player within the semiconductor packaging market. Processing in the back-end requires optimizing the use of intermediate carrier configurations such as tape-in-carrier and strip-based substrates. This optimization of carrier configurations must occur in all processes related to CSP assembly, including die attach, wire bond, encapsulation, ball attach, laser mark, singulate, inspect, and test. CSP is considered an SMT and, as such, can be processed using existing lines. However, CSP is different from SMT and has its own assembly problems. One of the critical problems is that, with thinner package profile requirement, thinner substrate is necessary. Another important problem that should be considered is the failure of solder joints because of the coefficient of thermal expansion mismatch among the substrate, lead packages, and the board when the thermal load is severe. To address this point, several studies using moire interferometry have been conducted to measure thermal deformations that accumulate during thermal cycles.     

A note on the robust stability of uncertain stochastic fuzzy systems with time-delays

Takagi-Sugeno (T-S) fuzzy models are now often used to describe complex nonlinear systems in terms of fuzzy sets and fuzzy reasoning applied to a set of linear submodels. In this note, the T-S fuzzy model approach is exploited to establish stability criteria for a class of nonlinear stochastic systems with time delay. Sufficient conditions are derived in the format of linear matrix inequalities (LMIs), such that for all admissible parameter uncertainties, the overall fuzzy system is stochastically exponentially stable in the mean square, independent of the time delay. Therefore, with the numerically attractive Matlab LMI toolbox, the robust stability of the uncertain stochastic fuzzy systems with time delays can be easily checked.     

An effective hybrid genetic algorithm for flow shop scheduling with limited buffers

As a typical manufacturing and scheduling problem with strong industrial background, flow shop scheduling with limited buffers has gained wide attention both in academic and engineering fields. With the objective to minimize the total completion time (or makespan), such an issue is very hard to solve effectively due to the NP-hardness and the constraint on the intermediate buffer. In this paper, an effective hybrid genetic algorithm (HGA) is proposed for permutation flow shop scheduling with limited buffers. In the HGA, not only multiple genetic operators based on evolutionary mechanism are used simultaneously in hybrid sense, but also a neighborhood structure based on graph model is employed to enhance the local search, so that the exploration and exploitation abilities can be well balanced. Moreover, a decision probability is used to control the utilization of genetic mutation operation and local search based on problem-specific information so as to prevent the premature convergence and concentrate computing effort on promising neighbor solutions. Simulation results and comparisons based on benchmarks demonstrate the effectiveness of the HGA. Meanwhile, the effects of buffer size and decision probability on optimization performances are discussed.     

An enhanced 0-1 mixed-integer LP formulation for traffic signal control

An enhanced 0-1 mixed-integer linear programming formulation based on the cell-transmission model is proposed for the traffic signal optimization problem. This formulation has several features that are currently unavailable in other existing models developed with a similar approach, including the components for handling the number of stops, fixed or dynamic cycle length and splits, and lost time. The problem of unintended vehicle holding, which is common in analytical models, is explicitly treated. The formulation can be utilized in developing strategies for adaptive traffic-control systems. It can also be used as a benchmark for examining the convergence behavior of heuristic algorithms based on the genetic algorithm, fuzzy logic, neural networks, or other approaches that are commonly used in this field. The discussion of extending the proposed model to capture traffic signal preemption in the presence of emergency vehicles is given. In terms of computational efficiency, the proposed formulation has the least number of binary integers as compared with other existing formulations that were developed with the same approach.     

双机架可逆冷轧机张力控制系统的研究

文章针对双机架可逆冷轧机的特点和轧制工艺要求,采用间接张力与直接张力复合控制法以实现卷取恒张力控制;提出了机架间张力控制系统的组成,描述了两种调张法的控制原理与实现方法.     

化学转化柱法测定气体中的微痕量水分的气敏分析仪的研究

采用特制LiAlH4催化反应柱,在(40～60)0C下,将气体中的微、痕量水转化成氢气.以气体中的微、痕量氢标准样品为标准,利用N型二氧化锡气敏半导体传感器作为检测器的气敏色谱方法,通过对转化的氢气进行准确测定,从而间接得出气体中微、痕量水的含量.研究表明,本文设计的催化反应装置选择性好,常温下反应快速、完全且稳定,一年来进行了近3000次试验考察表明,转化效率基本保持稳定,数据重复性很好.同时,气敏色谱法测水干扰因素少,进样量少,仅(1～2)ml,样品消耗少,仅(2～5)升,几分钟即可完成分析.该方法由于有微量氢标准气体作为相对标准,测水准确度高,不确定度为1%～10%.     

研究生教育管理模式探讨

随着研究生教育规模的扩大,研究生教育管理理念必须与时俱进.文章结合学校实际,从加强党的领导地位和凝聚力切入,围绕创新研究生素质教育、强化研究生自我管理、营造研究生成才环境等展开讨论,旨在探讨创建有特色的开放式研究生教育管理模式.