50MN自由锻造水压机电液伺服控制系统建模仿真

大型锻造水压机的电液伺服控制系统的可靠性和鲁棒性直接影响着水压机的使用、人身安全和锻件质量。针对50MN自由锻造水压机负载的不确定性,建立其电液位置伺服系统的数学模型,设计出动态鲁棒补偿器并结合传统的PID控制方法,利用MATLAB/SIMULINK软件仿真,结果表明动态鲁棒补偿器在水压机电液伺服系统中的应用很好地抑制了外负载干扰,提高了电液控制系统精度和稳定性。     

再论扩展目标的角闪烁

解释了角闪烁的两种物理概念及其计算方法;从数学上证明了远区角闪烁线偏差与雷达距离无关;以两个任意取向的电偶极子组成的典型目标为例,推导了考虑目标回波极化和接收天线极化时的角闪烁理论计算公式。理论分析和数值计算表明,在几何光学条件近似下,对线极化接收,相位梯度法与坡印亭矢量法完全等效。     

EMD新算法及其应用

经验模态分解（ENID）算法是Hilbert-Huang变换（HHT）的核心算法，它的分解效果依赖于包络线的生成算法和端点延拓算法。采用分段幂函数插值算法求包络成。结合一种改进的端点延拓算法。得到了一种新的EMD算法。分析了分段幂函数插值算法的收敛精度。从数学角度解释了选取该插值算法的原因．最后，结合一个股票模型的仿真结果说明新的EMD算法效果更好。     

A situation calculus based approach to dynamic management of e-business services

In the era of e-businesses, the traditional business services are greatly challenged by the ever-increasing demands from customers with various backgrounds and personalities. Large numbers of new e-businesses are driven by the needs of customers. The existing dynamics inherent in the customer needs require the corresponding dynamic management of services. Attempting to respond to customers in a rapid and intelligent way, this paper proposes a situation calculus based approach for dynamically managing e-Business services in the ubiquitous environment. By employing the formalism of the situation calculus to enable intelligence and automation, the approach can implement. the functions of service automatic composition and model verification. These functions will improve the degree of customer-orientation and enable fast responsiveness in the emerging e-service systems.     

Conflict analysis approaches for investigating attitudes and misperceptions in the War of 1812

Formal systems engineering approaches to modeling misperceptions and attitudes are employed within the framework of the graph model for conflict resolution to systematically study the War of 1812 between the United States of America and Great Britain in order to provide enhanced insights into the causes of the war. More specifically, relational definitions for preferences, movements and stability concepts are defined for describing the attitudes and associated behavior of decision makers involved in a conflict. To capture misperceptions of decision makers in the War of 1812, attitudes are studied within the structure of a hypergame. Combining attitudes and misperceptions within the paradigm of the graph model furnishes the flexible analytical tool which demonstrates that misunderstanding of attitudes by Great Britain and the United States may have contributed to the outbreak of this nasty war.     

THE λ-GROBNER BASES UNDER POLYNOMIAL COMPOSITION

Polynomial composition is the operation of replacing variables in a polynomial with other polynomials. λ-Grgbner basis is an especial Grobner basis. The main problem in the paper is： when does composition commute with λ-Grobner basis computation？ We shall answer better the above question. This has a natural application in the computation of λ-Grobner bases.     

A multiple intelligent agent system for credit risk prediction via an optimization of localized generalization error with diversity

Company bankruptcies cost billions of dollars in losses to banks each year. Thus credit risk prediction is a critical part of a bank＇s loan approval decision process. Traditional financial models for credit risk prediction are no longer adequate for describing today＇s complex relationship between the financial health and potential bankruptcy of a company. In this work, a multiple classifier system （embedded in a multiple intelligent agent system） is proposed to predict the financial health of a company. In our model, each individual agent （classifier） makes a prediction on the likelihood of credit risk based on only partial information of the company. Each of the agents is an expert, but has limited knowledge （represented by features） about the company. The decisions of all agents are combined together to form a final credit risk prediction. Experiments show that our model out-performs other existing methods using the benchmarking Compustat American Corporations dataset.     

Using Action Research to Improve Communication and Facilitate Group Work in a Multicultural Classroom: A South African Case Study

This study started with problems that my colleagues (and I) were experiencing with interaction and intercultural communication among students in our diverse classrooms. Educators were also experiencing difficulties in motivating students to work effectively in groups. The purpose of this paper was to seek solutions to these problems by exploring variations of the group oral assessment structure in a multilingual and multicultural context. Four phases of assessments were conducted at two tertiary institutions in South Africa using a combination of action research and a participatory approach. Not only did this study succeed in addressing the problems but it also revealed the added benefits of using an action research methodology.     

EXPLORATION/EXPLOITATION TRADEOFF WITH CELL-SHIFT AND HEURISTIC CROSSOVER FOR EVOLUTIONARY ALGORITHMS

In order to tradeoff exploration/exploitation and inspired by cell genetic algorithm a cellshift crossover operator for evolutionary algorithm （EA） is proposed in this paper. The definition domain is divided into n-dimension cubic sub-domains （cell） and each individual locates at an ndimensional cube. Cell-shift crossover first exchanges the cell numbers of the crossover pair if they are in the different cells （exploration） and subsequently shift the first individual from its initial place to the other individual＇s cell place. If they are already in the same cell heuristic crossover （exploitation） is used. Cell-shift/heuristic crossover adaptively executes exploration/exploitation search with the vary of genetic diversity. The cell-shift EA has excellent performance in terms of efficiency and efficacy on ten usually used optimization benchmarks when comparing with the recent well-known FEP evolutionary algorithm.     

INFORMATION CHARACTERIZATION OF COMMUNICATION CHANNELS FOR SYSTEM IDENTIFICATION

This paper studies identification of systems in which the system output is quantized, transmitted through a digital communication channel, and observed afterwards. The concept of the CR Ratio is introduced to characterize impact of communication channels on identification. The relationship between the CR Ratio and Shannon channel capacity is discussed. Identification algorithms are further developed when the channel error probability is unknown.