The Complete Solution of the Competitive Rank Selection Problem

Two decision-makers A and B observe sequentially a given permutation of n uniquely rankable options. A and B have one choice each (without recall) and both must make a choice. At each step only the relative ranks are known, and A has the priority of choice. At the end the (absolute) ranks are compared and the winner is the one who has chosen the better rank. Extending results by Enns and Ferenstein [6] and Berry et al. [1] this article gives, for both A and B , the optimal strategy and the corresponding winning probabilities. We show in particular that the limiting winning probabilities for A and B do exist, which closes a most important gap in the work of previous authors. This also provides an algorithm for numerically computing the limiting value of these probabilities. Although our proof is analytic in a strong sense, it is interesting to see that it would have been very hard to assemble it without the help of computer algebra. The reason is that the functions we have to investigate display subranges of indices which contrast considerably with respect to error terms when certain terms are replaced by approximations, and that computations were very helpful to locate those ranges where a particularly fine tuning of error estimates turned out to be indispensable. Received October 1997; revised March 15, 1998.     

多路高速信号采集、记录与回放系统设计

为了准确地记录测控系统的测量数据，本文提出了一种基于SCSI硬盘的多路高速信号采集、记录与回放系统的设计方法，给出了系统的总体结构，阐述了采集电路的设计、SCSI硬盘控制的设计和抗干扰方法。本文提出的设计方法能满足多种应用场合，具有广泛的应用前景。     

遗传算法的收敛性分析

理论分析算法发生过早收敛的原因、收敛速度与各个控制参数以及适应度函数的关系,并提出与证明了判断遗传算法收敛性的统一判据。     

机器人仿生膝关节的计算力矩加比例微分反馈控制

磁流变阻尼器控制的四连杆关节瞬时转动中心是变化的,仿生特性好,但机构模型复杂,模拟人腿关节运动时变轨迹跟踪较为困难.基于此,提出行走机器人四连杆仿生膝关节机构,建立虚拟样机、机构动力学简化模型和磁流变阻尼器Bingham模型.基于瞬时转动中心和简化的关节几何中心,引入大小腿长度变化以减少模型误差.设计计算力矩加比例微分反馈控制算法来控制关节摆动.采用Lyapunov方法,分析在模型存在误差情况下,控制算法的收敛性和跟踪误差大小.在虚拟样机上对阻尼力和关节摆动运动进行仿真,在样机上对控制算法进行验证.试验结果表明,引入瞬时中心和几何中心,可降低模型误差,控制算法轨迹跟踪精度能满足行走机器人行走要求.     

自整角机轴角信息采集记录仪的设计

介绍了一种由单片轴角／数字转换集成电路AD2S83、单片机以及大容量存储器构成的自整角机轴角信息采集记录仪的总体设计。该采集记录仪能将自整角机的三相模拟信号及参考信号转换为表示轴角位置、角速度等信息的数字量。可以对转换结果进行处理、存储或传输，在含有自整角机的系统的研究开发、状态监测等场合具有实用价值。     

3D ECT reconstruction by an improved Landweber iteration algorithm

Electrical capacitance tomography (ECT) is a relatively mature non-invasive imaging technique that attempts to map dielectric permittivity of materials. Recently, 3D ECT has gained interest because of its potential to generate volumetric images. The study of a fast and accurate image reconstruction algorithm is a challenge task, especially for 3D reconstruction. In this paper, we propose an improved Landweber iteration algorithm. We incorporate an additional acceleration term into the cost function and apply an adaptive threshold operation to the image obtained in each iteration for reducing artefacts. The algorithm proposed is tested by the noise-free and noise-contaminated capacitance data. Sensitivity matrixes and capacitance data of a 3D ECT sensor are obtained by using the finite element (FE) method. Extensive simulations in 3D reconstruction are carried out. The results verify the effectiveness of these improvements. Both the reconstruction time and the artefacts in the reconstructed image are reduced obviously. The experimental results of 3D reconstruction of objects in the shape of letters U and L confirm the effectiveness of the proposed algorithm further.     

Two-stage iterations based on composite splittings for rectangular linear systems

In this paper, we introduce a two-stage method to solve rectangular linear systems that exhibits faster convergence than typical stationary iterative methods. Under suitable conditions, we prove convergence of the new method. The number of outer iterations can be reduced by using a few significant number of inner iterations for efficient computations. Further, we perform a comparison analysis, and establish that a higher number of inner iterations ensures a smaller spectral radius of the global iteration matrix. We also discuss the uniqueness of a proper splitting, and illustrate different comparison theorems for different subclasses of proper splittings.     

Low climate stabilisation under diverse growth and convergence scenarios

In the last decade a number of papers have analysed the consequences of achieving the greenhouse gas concentration levels necessary to maintain global temperature increases below 2 °C above preindustrial levels. Most models and scenarios assume that future trends in global GDP will be similar to the growth experienced in the past century, which would imply multiplying current output by about 19 times in the 21st century. However, natural resource and environmental constraints suggest that future global economic growth may not be so high. Furthermore, the environmental implications of such growth depend on how it is distributed across countries. This paper studies the implications on GHG abatement policies of low global GDP growth and high convergence levels in GDP per capita across countries. A partial equilibrium model (POLES) of the world's energy system is used to provide detailed projections up to 2050 for the different regions of the world. The results suggest that while low stabilisation could be technically feasible and economically viable for the world in all the scenarios considered, it is more likely to occur with more modest global growth. However, that will imply higher global abatement costs relative to GDP. Convergence in living standards on the other hand places greater pressures in terms of the required reduction in emissions. In general we find that there are major differences between regions in terms of the size and the timing of abatement costs and economic impact.     

MAC finite difference scheme for Stokes equations with damping on non-uniform grids

In this paper, we consider the numerical methods for stationary Stokes equations with damping. The mark and cell(MAC) method has been applied to discretize the problem on non-uniform grids. We establish the LBB condition and the stability for the MAC scheme. Then we obtain the second order super-convergence in L2 norm for both velocity and pressure on non-uniform grids. We also obtain the second order convergence for some terms of H1 norm of the velocity, and the other terms of H1 norm are second order convergence on uniform grids. Numerical experiments using the MAC scheme show agreement of the numerical results with theoretical analysis.     

Feasibility and modelling for convergence of optical-wireless network – A review

Now a days, the convergence of wireless and optical network gaining popularity to enhance the data carrying capacity, QoS and to support future multimedia applications. The queue theory plays an important role for analytically evaluating such converged networks. In the everyday state of affairs, queue phenomena are observed in the several situations like the health clinic, railway reservation system, automobile laundry centre, bank cash counter, call centre, etc. Similarly, the phenomenon of congestion is ascertained in the telephone network, computer network, communication systems and the Internet wherever nonstop enhancements need to be created to stay up with the quickly growing demand. The subsistence of these adverse clogging effects has lead toward the improvement of queuing theory-based statistical models. Therefore, these queues based statistical models answering to optimising queries corresponding to the way for assigning resources in converged optical and wireless networks. During this paper, a review on the role of the queuing model in wireless & optical communication is presented that concentrate on the present and future aspects of research.