Stability and Distributed Scheduling Algorithms

Many distributed scheduling algorithms have been developed and reported in the current literature. However, very few of them explicitly treat stability issues. This paper first discusses stability issues for distributed scheduling algorithms in general terms. Two very different distributed scheduling algorithms which contain explicit mechanisms for stability are then presented and evaluated with respect to individual specific stability issues. One of the agorithms is based on stochastic learning automata and the other on bidding. The results indicate how very specific the treatment of stability is to the algorithm and environnent under consideration.     

NURBS modeling and structural shape optimization of cardiovascular stents

Cardiovascular stents have been used since the 1990s to treat atherosclerosis, one of leading causes of death in the western world, and structural optimization has led to significant improvements in stent performance. Much of the potential variation in stent geometry, however, has remained unconsidered. This paper presents a non-uniform rational basis spline (NURBS) parameterization of a stent, the inclusion of structural fatigue resistance as a design consideration, and the results of a design optimization based on response surface techniques. Results show the feasibility and merits of the NURBS approach, which models a much broader range of shapes than was previously possible. Multi-objective optimization produces a range of geometrically diverse Pareto-optimal designs; these can be used to develop future clinical design guides, accounting for the variation observed across patients. We conclude by motivating future work with increasingly complex physical modeling and optimization capabilities.     

Delphi实现EMIF规范中XML报文的生成与解析

针对EMIF规范中XML报文处理，基于Delphi及XML Data Binding技术设计并实现了XML报文的生成与解析方法，为参照EMIF规范进行教育管理信息系统开发或利用Delphi进行XML相关开发的人员提供参考。     

基于凸壳和模糊识别的数学公式识别

根据数学公式中字符或符号间空间关系特点,并针对目前用于数学公式字符空间关系判别的区域和质心方法所存在的不足,提出了基于字符凸壳和模糊识别的字符空间关系判别方法.首先,对数学公式中的字符或符号进行分类,对每一类运用字符凸壳判别其正上和正下关系,然后应用模糊识别的方法对常见关系进行识别.实验结果表明,运用该方法能明显提高字符空间关系判别的识别率,识别的正确率可达到93.5%.     

A Camera Engine for Computer Games: Managing the Trade-Off Between Constraint Satisfaction and Frame Coherence

Many computer games treat the user in the "1st person" and bind the camera to his or her view. More sophistication in a game can be achieved by enabling the camera to leave the users' viewpoint. This, however, requires new methods for automatic, dynamic camera control. In this paper we present methods and tools for such camera control. We emphasize guiding camera control by constraints ; however, optimal constraint satisfaction tends to lead to the camera jumping around too much. Thus, we pay particular attention to a trade-off between constraint satisfaction and frame coherence. We present a new algorithm for dynamic consideration of the visibility of objects which are deemed to be important in a given game context.     

一种新型隐私数据库秘密同态检索协议

针对隐私数据查询中的隐私泄露威胁模型,本文提出了一种新型隐私数据库秘密同态检索协议,该协议基于SomeWhat部分同态算法进行设计,通过使用密文同态运算性质较好的解决了该威胁模型中涉及到的隐私泄露问题,同时本文在证明该协议正确性和安全性的基础上,通过适当的参数选择,对该协议的同态算法进行了测试,给出了算法的运行效率。     

Fuzzy set based crack diagnosis system for reinforced concrete structures

This paper presents a computer assisted crack diagnosis system for reinforced concrete structures which aids the non-expert to diagnose the cause of cracks at the level of an expert in the general inspection of structures. The system presented adapts fuzzy set theory to reflect fuzzy conditions, both for crack symptoms and characteristics which are difficult to treat using crisp sets. The inputs to the system are mostly linguistic variables concerning the crack symptoms and some numeric data about concrete and environmental conditions. Using these input data and based on built-in rules, the proposed system executes fuzzy inference to evaluate the crack causes under consideration. The built-in rules were constructed by extracting expert knowledge, primarily from technical books about concrete and concrete cracks. We implemented the proposed system in a computer program with a graphic user interface for actual utilization in practical business fields. When applied to cracks actually diagnosed by experts, the proposed system provided results similar to those obtained by experts, and we expect that this system can be used as an effective crack diagnosis tool for both experts and non-experts in the regular inspection of RC structures.     

An automated bi-level optimization approach for IMRT

Intensity-modulated radiation therapy is used worldwide to treat cancer patients. The objective of this treatment is to deliver a prescribed radiation dose to the tumor while sparing, as much as possible, all the healthy tissues, especially organs at risk (OAR). This means that the planning of a radiotherapy treatment should take into consideration conflicting objectives: to be able to spare as much as possible the OAR guaranteeing, at the same time, that the desired radiation is delivered to the volumes to treat. While the volumes to treat can be adequately irradiated from almost any set of directions, the radiation directions that are chosen have a determinant impact on the OAR. This means that those directions that provide an improved OAR sparing should be selected. The choice of radiation directions (beam angles) can thus be interpreted as being fundamentally determined by the OAR, with the radiation intensities associated with each of these directions being determined by the needed radiation to be delivered to the volumes to treat. In this work, we interpret the radiotherapy treatment planning problem as a bi-level optimization problem. At the upper level, OAR control the choice of the beam angles, which are selected aiming at OAR sparing. At the lower level, the optimal radiation intensities are decided by the volumes to treat, considering the beam angle ensemble obtained at the upper level. The proposed bi-level approach was tested using 10 clinical head-and-neck cancer cases already treated at the Portuguese Institute of Oncology in Coimbra.     

复杂电磁环境下防空雷达的探测模型研究

现代战场处于复杂的电磁对抗环境之中,在空袭与防空作战中,制电磁权的斗争集中表现在雷达领域,防空雷达的探测模型是防空作战仿真中不可或缺的重要模型.传统的雷达模型对复杂电磁环境考虑的不够,模型通常为距离模型而非概率模型,并且模型参数过于复杂,不适合大规模作战仿真的需要.针对复杂电磁环境下电子对抗和雷达装备的特点,在雷达距离方程的基础上,对雷达探测的某些问题做了合理的简化,参考雷达探测的BLAKE图解法,采用功能性仿真,计算统计意义上的雷达探测概率,建立了雷达探测的概率模型和仿真算法.通过仿真结果与相关型号试验数据的印证,表明模型能够确切反映相关雷达的真实作战效能,适合作战仿真的需要.     

基于邻近序列的IP地址地理定位方法

IP地址地理定位旨在准确地确定给定的IP地址的物理空间位置,通常采用基于测量的技术或者基于数据分析的技术。现有的基于数据分析的IP地址地理定位技术,对IP地址之间的关系考虑较少。考虑到IP地址的聚集特性,提出了一种基于邻近序列的IP地址地理定位方法。首先计算IP地址的邻近序列,并将其转化为对应的经纬度序列,然后建立模型并求解。以IP地址定位库和含有GPS信息的移动流量数据为原始数据,对该方法进行了实验验证。实验结果表明,通过邻近IP序列确实可以确定IP地址的物理空间位置,平均定位误差在20～30km,实现了区县一级的定位。该方法给IP地址地理定位问题提供了新的解决方案,同时该方法也可以与其他基于测量或者基于数据分析的方法相结合,以获得更优的结果。     

Inspection of free-form shaped parts

Free-form surface inspection requires the measurement surface and the corresponding design model in a common coordinate system so that comparison between the two surfaces can be made. In practical engineering applications, the free-form shaped parts are sometimes assigned profile tolerance with or without the reference of design datum(s) based on consideration of assembly, functionality and other manufacturing requirements. This paper discusses the profile verification techniques for free-form surface inspection with and without datums. The inspection of free-from surfaces includes two major processes: (1) the localization of measurement data to design coordinate system based on the datum reference information or a number of extracted surface features; and (2) the further localization based on the surface characteristics so that the deviation of the measured surface from the design model is minimized. Implementation and tests of inspection samples have been carried out to verify the developed inspection techniques.     

Economics‐inspired decentralized control approach for adaptive grid services and applications

Grid technologies facilitate innovative applications among dynamic virtual organizations, while the ability to deploy, manage, and properly remain functioning via traditional approaches has been exceeded by the complexity of the next generation of grid systems. An important method for addressing this challenge may require nature‐inspired computing paradigms. This technique will entail construction of a bottom‐up multiagent system; however, the appropriate implementation mechanism is under consideration in order for the autonomous and distributed agents to emerge as a controlled grid service or application. A credit card management service in economic interactions is considered in this article for a decentralized control approach. This consideration is based on a preliminarily developed ecological network‐based grid middleware that has features desired for the next generation grid systems. The control scheme, design, and implementation of the credit card management service are presented in detail. The simulation results show that (1) agents are accountable for their activities such as behavior invocation, service provision, and resource utilization and (2) generated services or applications adapt well to dynamically changing environments such as agent amounts as well as partial failure of agents. The approach presented herein is beneficial for building autonomous and adaptive grid applications and services. © 2006 Wiley Periodicals, Inc. Int J Int Syst 21: 1269–1288, 2006.     

Texts on-line

The study of signs is divided between those scholars who use the Saussurian binary sign (semiology) and those who prefer Charles Peirce's tripartite sign (semiotics). The common view of the opposition between the two types of signs does not take into consideration the methodological conditions of applicability of these two types of signs. This is particularly important in the field of literary studies and hence for the preparation of electronic programs for text analysis. The Peircian sign explicitly entails the discovery of a truth of meaning that claims to be universal and not reducible to a collection of opinions based on fragmented information; it also imposes the task of elucidating a transhistorical and universal significantion encoded in a text. Contrary to Peirce's view of the sign, our use of computer programs for text analysis, however, demonstrates that we implicitly treat every literary text as a set of linguistic data (letters, phonemes, syntagmatic segments, etc.) which are reducible to units that can be treated separately. A brief comparison of the results obtained from computer analyses of the French poet Stéphane Mallarmé's text, “Le Cygne,” with those obtained from two Peircian analyses (by Riffaterre and Champigny) of the same text demonstrates that our current methods of computer textual analysis are based on a Saussurian semiology, which is unidimensional and limited, and that these methods are still quite unable to produce a semiotic interpretation based on a totalizing hierarchy of the text's various discursive components.     

An integrated approach for the consideration of uncertainty in decision making supported by Life Cycle Assessment

This paper presents an approach for the integrated consideration of both technical and valuation uncertainties during decision making supported by environmental performance information based on Life Cycle Assessment (LCA). Key elements of this approach include “distinguishability analysis” to determine whether the uncertainty in the performance information is likely to make it impossible to distinguish between the activities under consideration, and the use of a multivariate statistical analysis approach, called principal components analysis (PCA), which facilitates the rapid analysis of large numbers of parallel sets of results, and enables the identification of choices that lead to similar and/or opposite evaluations of activities. The integrated approach for the management of uncertainty is demonstrated for a technology selection decision for the recommissioning of a coal-based power station. The results of the case study decision suggest that stakeholder involvement in preference modelling is important, and that the “encoding” of value judgements and preferences into LCA environmental performance information is to be avoided. The approach presented in this paper provides a foundation for the consideration of the implications of diversity in values and preferences as part of an overall approach to promote effective decision making based on LCA environmental performance information. However, the approach is more universally applicable – it can be used wherever multiple criteria decision analysis is used to assist in the resolution of complex decision situations.     

WSN中移动单点信号源的重建算法

现有移动信号源估计算法没有综合考虑采样点之问存在的空间相关性或难以适应运动信号源,针对该问题提出一种基于空间相关性的能量优化移动单点信号重建算法。该算法对事件源进行运动预测,确定发送监测数据的最佳距离,以降低网络通信量。实验结果证明了其有效性。     

Robust regulation of a class of partially observed nonlinear continuous bioreactors

We propose a design of robust dynamic output feedback for the global partial stabilization of a class of continuous stirred bioreactors. Our approach is robust with respect to exogenous disturbances and functional uncertainties of the kinetics, considered as bounded unknown inputs. The method is based on a design of dynamic guaranteed bounds on the unmeasured variables, conditioned to past measurements and given bounds on the initial condition. This approach is suitable to systems which are not detectable for unknown inputs. The flexibility in the design of the parameters allows the consideration of saturation constraints on the control variable.     

Sensors and observers in distributed parameter systems

Luenberger observer theory is extended to distributed parameter systems. This extension is based on the consideration of sensors. For systems with infinite dimensional state spaces, it is possible to construct the state vector asymptotically (or a part of the state vector) by a ‘good’ choice of sensors. We show that the link between detectability and sensor structure may be of some interest in the construction of observers.     

Control Synthesis of Singularly Perturbed Fuzzy Systems

This paper considers the problem of designing stabilizing and H_infin controllers for nonlinear singularly perturbed systems described by Takagi-Sugeno fuzzy models with the consideration of the bound of singular perturbation parameter e. For the synthesis problem of simultaneously designing the bound of e and stabilizing or H_infin controllers, linear matrix inequalities (LMI)- based methods are presented. For evaluating the upper bound of e subject to stability or a prescribed H_infin performance bound constraint for the resulting closed-loop system, sufficient conditions are developed, respectively. For the stabilizing and H_infin control synthesis without the consideration of improving the bound of e, new design methods are also given in terms of solutions to a set of LMIs. Examples are given to illustrate the efficiency of the proposed methods.     

Control design for a class of nonlinear continuous-time systems

This paper addresses the control design problem for a certain class of continuous-time nonlinear systems subject to actuator saturations. The system under consideration consists of a system with two nested nonlinearities of different type: saturation nonlinearity and cone-bounded nonlinearity. The control law investigated for stabilization purposes depends on both the state and the cone-bounded nonlinearity. Constructive conditions based on LMIs are then provided to ensure the regional or global stability of the system. Different points, like other approaches issued from the literature, are quickly discussed. An illustrative example allows to show the interest of the approach proposed.