Robust model predictive control for discrete uncertain nonlinear systems with time-delay via fuzzy model

INTRODUCTION In recent years, research on nonlinear model predictive control has attracted significant attention because most practical processes are nonlinear. In industry process control, model predictive controllers based on linear models (LMPC) are often used to control nonlinear systems. When the operating con- ditions undergo significant changes, the performance of LMPC can deteriorate drastically. Under such conditions, predictive control based on nonlinear models (NMPC) shoul…     

Exploring the Relationship between State Financial Aid Policy and Postsecondary Enrollment Choices: A Focus on Income and Race Differences

This study explores the relationship between state financial aid policies and postsecondary enrollment for high school graduates (or equivalent diploma holders). Utilizing an event history modeling for a nationally representative sample from the National Education Longitudinal Study (NELS:88/2000) in addition to state-level policy variables, this study examined how state aid policies differentially affect students’ postsecondary enrollment choices depending on their family income and race/ethnicity between the years 1992 through 2000. The findings demonstrate that there is a clear and consistent gap in college enrollment for students who are from different income and race/ethnic groups, and that changes in state financial aid policy are significantly related with the type of institutions a student attends across income and racial groups. The study findings have important implications for state aid policy as well as future research on the role of public financial aid policy in college choice of students from different income and racial/ethnic backgrounds.     

An exchange rate determination model for central banks’ interventions in financial markets

We establish an exchange rate determination model for central banks’ interventions in financial markets. The model shows that central banks can adjust exchange rate by several policy instruments and that different instruments may have different effects on exchange rate determination. It specifies potential policy instruments for central banks as well as their policy effects. Based on these effects, feasible matches of policy instruments in contingent intervention are put forth. Project supported by the National Natural Science Foundation of China (No. 79870074)     

Cluster parallel rendering based on encoded mesh

INTRODUCTION Three dimensional (3D) meshes are widely used to represent 3D objects. With the rapid advances in digital acquisition technology, meshes with millions of vertices are becoming increasingly common. Be- cause of memory constraints and lack of graphics power, visualizations of this magnitude are difficult or impossible to perform even on the most powerful workstations. Therefore, the need for parallel im- plementation is clear. Most previous work in high performance rendering h…     

Extending attributes page: a scheme for enhancing the reliability of storage system metadata

In an object-based storage system, a novel scheme named EAP （extending attributes page） is presented to enhance the metadata reliability of the system by adding the user object file information attributes page for each user object and storing the file-related attributes of each user object in object-based storage devices. The EAP scheme requires no additional hardware equipments compared to a general method which uses backup metadata servers to improve the metadata reliability. Leveraging a Markov chain, this paper compares the metadata reliability of the system using the EAP scheme with that using only metadata servers to offer the file metadata service. Our results demonstrate that the EAP scheme can dramatically enhance the reliability of storage system metadata.     

Control system for dynamic testing platform of asymmetrical pitch mechanism

A novel asymmetrical pitch system for rotary wing is presented. The pitch control characteristics are studied and analyzed. Because elastic linkage is a key part in whole asymmetrical pitch system, in order to obtain the variation of the elastic linkage deformation, an experimental platform mainly based on the device of micro aerial vehicles (MAVs) and a new control system mounted on TMS320LF2407 are designed. This control system has its compacted configuration and reliability. Finally, using this system to control the MAV for simulating the flying forward, experimental results show the MAV’s flight attitude can be controlled based on the variation of the elastic linkage. Project supported by the National Natural Science Foundation of China (Grant No.60605028), the National High-Technology Research and Development Program of China (Grant No.2007AA04Z225), the Shanghai Rising-Star Program (Grant Nos.07QA14024, 07QH14006), the Shanghai Shuguang Program (Grant No.07SG47), and the Shanghai Leading Key Laboratory of Mechanical Automation and Robotics Science Foundation (Grant No.ZZ0805)     

A pooled-neighbor swarm intelligence approach to optimal reactive power dispatch

INTRODUCTION The reactive power dispatch is aimed at mini- mizing the active power loss in the transmission network by allocating the reactive power generation under several security constraints. The reactive power dispatch problem has significant influence on secure and economic operation of power systems. The reac- tive power generation affects the overall generation cost via transmission loss. A procedure which allo- cates the reactive power generation so as to minimize the transmissio…     

Influence of input acoustic power on regenerator＇s performance

Performance of a pulse tube cooler significantly depends on the efficient operation ofits regenerator. Influence of input acoustic power on regenerator＇s performance is simulated and analyzed with simple harmonic analysis method. Given regenerator＇s dimensions and pressure ratio, there is an optimal input acoustic power for achieving a highest coefficient of performance, due to a compromise between relative time-averaged total energy flux in regenerator and relative acoustic power at regenerator＇s cold end. Additionally, optimal dimensions of regenerator are also estimated and presented for different input acoustic powers. The computed optimal diameter obviously increases with increase of input acoustic power, while the optimal length decreases slightly, and as a result, a larger input acoustic power requires a smaller aspect ratio （length over diameter）.     

A laser shaft alignment system with dual PSDs

INTRODUCTION Precise alignment occurs when the centerlines of rotation of two shafts are essentially collinear with each other. The degree to which two machines are misaligned can be determined by examining the amount of offset and angularity that exists between them. Offset is the distance between the two rota- tional centerlines, and angularity is the angle between the centerlines created by the misalignment of the two centerlines. The traditional precise shaft alignment method is dial …     

Preventive repair policy and replacement policy of repairable system taking non-zero preventive repair time

The repairable system with preventive maintenance is one of the typical systems with wide useful applications in engineering. If the system can be made as good as new by preventive maintenance, both the life stochastic variable of different periods and fault correction time stochastic variable form monotonous stochastic process. Based on the above assumption and the available results, in this paper we discuss the maintenance and replacement policy of the repairable system with preventive maintenance. The intervals of preventive maintenance, T, and the times of system failure, N, are introduced and the vector Markov process method is used. The formulation of steady state average profit rate can be deduced to solve the optimization problem of the maintenance and replacement policy.     

Construction simulation and real-time control for high arch dam

A method of combining dynamic simulation with real-time control was proposed to fit the randomness and uncertainty in the high arch dam construction process. The mathematical logic model of high arch dam construction process was established. By combining dynamic construction simulation with schedule analysis, the process of construction schedule forecasting and analysis based on dynamic simulation was studied. The process of real-time schedule control was constructed and some measures for dynamic adjustment and control of construction schedule were provided. A system developed with the method is utilized in a being constructed hydroelectric project located at the Yellow River in northwest China, which can make the pouring plan of the dam in the next stage (a month, quarter or year) to guide the practical construction. The application result shows that the system provides an effective technical support for the construction and management of the dam. ZHONG Denghua, born in 1963, male, Dr, Prof. Supported by National Natural Science Foundation of China(No.50539120), National Basic Research Program of China(“973”Program,No. 2007 CB714101), National Science Fund for Distinguished Young Scholars of China(No.50525927), and National Natural Science Foundation of China (No.50579045).     

Predictive functional control (PFC) and its application in chlorinated polyethylene process

The main principle and the characteristic of Predictive Functional Control (PFC) strategy are presented in this paper and the corresponding control system aid design software APC-PFC is also introduced. For a chlorinated polyethylene (CPE) process, a design scheme of cascade predictive functional control system is described and the control performance is improved obviously. Project (No. 69974035) supported by the National Natural Science Foundation of China     

Design of H∞ robust fault detection filter for nonlinear time-delay systems

INTRODUCTION Due to increasing demand for higher perform- ance, as well as for higher safety and reliability standards, the model-based approaches to fault de- tection and isolation (FDI) for dynamic systems have received more and more attention during the last two decades (Chen and Patton, 1999; Chen and Saif, 2006 Frank and Ding, 1997; Gao and Wang, 2006; Jiang and Zhou, 2005; Zhou et al., 1998). Among these model-based approaches, the most common way is the observer-based approach…     

教育对中国收入不平等变迁的作用:1991～2006

中国的改革开放引发了经济的迅速增长,同时也造成了贫富差距扩大的问题,并成为中国进一步发展的瓶颈。本研究尝试在北卡罗大学卡罗人口中心和中国疾病预防控制中心营养与食品安全所合作调查的中国健康与营养调查(1991～2006)数据基础上,应用整体分布反事实模拟法对教育对中国收入不平等变迁的影响进行研究。研究发现,1991～2006年间,教育扩展对中国收入不平等变迁的作用表现为U字形趋势,即表现为扩大—扩大的强度减少—缩小—缩小的强度增大的趋势作用;而教育收益率的变化对中国收入不平等的作用表现为倒U字形方向,即缩小—扩大—扩大的强度增强—强度缩小的趋势作用。结论表明,教育对收入不平等的变化有所作为,但是要发挥教育改善收入不平等的作用,需要提高低收入群体的教育水平,改善教育自身的分配平等。     

New finding on out-of-step separation configuration of large-scale power systems

In this paper,two new concepts—“main out-of-step mode” and “minor out-of-step mode”—are proposed for power system reliability analysis. Large-scale power system studies found that out-of-step generator groups may have characteristics of the main out-of-step mode and the minor out-of-step mode. The generator groups with main out-of-step modes can determine the out-of-step interface of the large-scale power system,while generators with the minor out-of-step modes cannot play such a role. Therefore,the method of capturing the out-of-step interface by seeking the lowest voltage point(the out-of-step center) can only group the generators with the main out-of-step modes,and may fail to combine the generators with the minor out-of-step modes into proper coherent generator groups. Thus,it is necessary in engineering applications to equip the generators that are likely to have the characteristics of the minor out-of-step modes with separation devices based on off-line simulation studies in order to reduce the risk of further accidents caused by these generators after system separation.     

带干扰的广义泊松过程模型及其破产概率

在一般的风险模型中，都假定保险公司的保费收入为时间的线性函数，但在实际情况中，保险公司的保费收入与保险公司售出的保单数和每份保单的保额有关．在保险理赔的广义泊松过程模型中，加入扩散扰动项，并假定保费收入为一泊松过程，建立起新的模型，证明了新模型下的破产概率满足Lundberg不等式．     

Stress analysis of anisotropic thick laminates in cylindrical bending using a semi-analytical approach

Semi-analytical elasticity solutions for bending of angle-ply laminates in cylindrical bending are presented using the state-space-based differential quadrature method (SSDQM). Partial differential state equation is derived from the basic equations of elasticity based on the state space concept. Then, the differential quadrature (DQ) technique is introduced to discretize the longitu- dinal domain of the plate so that a series of ordinary differential state equations are obtained at the discrete points. Meanwhile, the edge constrained conditions are handled directly using the stress and displacement components without the Saint-Venant principle. The thickness domain is solved analytically based on the state space formalism along with the continuity conditions at interfaces. The present method is validated by comparing the results to the exact solutions of Pagano’s problem. Numerical results for fully clamped thick laminates are presented, and the influences of ply angle on stress distributions are discussed.     

Science Letters: Lattice type transmission line of negative refractive index

In this letter, we introduce a novel passive transmission line of negative refractive index （i.e., left-handedness） based on identical symmetrical lattice type structures [thus called ＂lattice type transmission line＂ （LT-TL）]. The dispersion characteristic and the transmission response of the proposed LT-TL are analyzed. While all the other left-handed passive transmission lines are of high pass, the present passive left-handed transmission line is of low pass. Compared with a conventional transmission line, the LT-TL has a phase shift of 180° in the entire wide pass-band.     

我国高等学校学费标准与居民收入水平、GDP的增长分析

高等学校实行收费政策是中国高等教育体制的一项重大改革。通过将高校学费标准的增长与城乡居民收入、人均GDP的增长进行比较分析,得出我国高校学费标准的增长大大高于人均收入水平及人均GDP的增长速度。     

Predictive control of a class of bilinear systems based on global off-line models

INTRODUCTION Bilinear systems are a kind of important nonlinear systems with relatively simple structure, and many industrial processes can be described as a bilinear system. Thus research on the control of this kind of systems is very important. On the other hand, model predictive control (MPC) (Clarke et al., 1987) has been widely used in industrial applications and many predictive control methods focusing on bilinear systems are emerging (Bloemen et al., 2001; Fontes et al., 2004; He…