Analysis of leakage current in GaAs micro-solar cell arrays

The output characteristics of micro-solar cell arrays are analyzed on the basis of a modified model in which the shunt resistance between cell lines results in current leakage.The modification mainly consists of adding a shunt resistor network to the traditional model.The obtained results agree well with the reported experimental results.The calculation results demonstrate that leakage current in substrate affects seriously the performance of GaAs micro-solar cell arrays.The performance of arrays can be imp...     

Performance of Muse on switch-based multiprocessor machines

The Muse (multiple sequential Prolog engines) approach has been used to make a simple and efficient OR-parallel implementation of the full Prolog language. The performance results of the Muse system on bus-based multiprocessor machines have been presented in previous papers. This paper discusses the implementation and performance results of the Muse system on switch-based multiprocessors (the BBN Butterfly GP1000 and TC2000). The results of Muse execution show that high real speedups can be achieved for Prolog programs that exhibit coarse-grained parallelism. The scheduling overhead is equivalent to around 8–26 Prolog procedure calls per task on the TC2000. The paper also compares the Muse results with corresponding results for the Aurora OR-parallel Prolog system. For a large set of benchmarks, the results are in favor of the Muse system.     

Stabilization of Takagi–Sugeno Model via Nonparallel Distributed Compensation Law

This paper addresses the stabilization of nonlinear systems, which is represented by a Takagi–Sugeno (T–S) model. Based on the extended nonquadratic Lyapunov function and the nonparallel distributed compensation law, three new results are obtained by using appropriate slack matrices, collection matrices, and the higher dimensional collection matrix. The first two results are less conservative, and computationally less expensive, than some of the existing results. The third result combines the procedures of the first two results, and is less conservative, but is computationally more expensive than the first two results. The effectiveness of the new results is validated by two numerical examples.      

DynaForm在汽车顶盖重力变形评估中的应用

针对大型面板的重力变形在整车车型设计和生产过程中易被忽略的问题,用DynaForm对某车型的顶盖进行重力变形评估,并验证软件评估结果与实验结果的一致性.结果表明:DynaForm的模拟结果与实验结果基本符合,零件的重力变形评估意义重大.研究结果对于DynaForm在零件重力变形方面的应用和实际生产具有参考和指导意义.     

Strength analysis of steam turbine valves frames

The paper presents a method of analysis of frames strength of steam turbine regulating valves. The frames by finite elements are modeled. The calculation results are presented in form of maps of the reduced node mean stresses. The results of numerical calculations are compared with the investigation results obtained experimentally.     

Application of variational methods to a rectangular clamped plate problem

The present paper deals with the variational approach for solving a clamped rectangular plate under a uniform load. The increasing use of composite materials for plate-type structures intensified the need for solutions of rectangular plates. The variational approach has a broad range of applications in solid mechanics. The methods used to solve the problem consider the minimum total potential energy approach. The maximum deflection is obtained for a square plate by the Ritz, Galerkin and Kantorovich methods. The aim of this paper is to find an approximate solution of higher accuracy. Numerical results for various components of stresses are found and plotted in the form of curves. The results obtained by various methods are compared with those reported earlier. The results show reasonable agreement with the known results, but with a simple and practical approach. The physical aspect of the concept is the immediate use of these results in solid and structural mechanics.     

Analysis of slab-on-girder bridges

Grid models of three short-span steel girder bridges are developed and analyzed. The techniques used to develop grid models are discussed. Stresses and deflections from the grid analyses are compared to results of field load tests of the bridges. It is found for all three bridges that the grid analyses are able to reproduce the maximum measured stresses within 30%. The grid analysis results are also compared to results from the AASHTO wheel load distribution factor method for two of the bridges. The grid analysis results were found to match the measured results more closely in both cases.     

一种基于冗余消除的本体映射后处理方法

现有的本体映射研究大多只关注映射方法本身,而缺乏对映射结果的具体分析,使得已有的映射结果供本体重用时应用效率不高。因此,本文提出一种基于冗余消除的本体映射后处理方法来对已有映射结果进行处理,以获得最优基础映射集,提高本体映射重用的效率。实验结果表明,本文方法在精简映射规模和提高映射重用效率上的表现均较优。     

Using neural networks to predict the design load of cold-formed steel compression members

The paper considers the use of neural networks to predict the failure load of cold-formed steel compression members. The objective is to provide a fast method of predicting the failure load, so that the method can be used in other design algorithms, such as optimisation routines. Three types of symmetric sections are considered, and the results of neural network predictions compared with results from BS5950 Part 5. The results are in good agreement with the results from design codes. Moreover, a trained neural network gives the results significantly more quickly than a computer implementation of the code.     

Global asymptotic stability of recurrent neural networks with multiple time-varying delays.

In this paper, several sufficient conditions are established for the global asymptotic stability of recurrent neural networks with multiple time-varying delays. The Lyapunov-Krasovskii stability theory for functional differential equations and the linear matrix inequality (LMI) approach are employed in our investigation. The results are shown to be generalizations of some previously published results and are less conservative than existing results. The present results are also applied to recurrent neural networks with constant time delays.     

多搜索引擎权重计算及搜索结果排序质量评估

搜索引擎在多成员搜索引擎搜索结果的整合过程中,搜索结果的排序在很大程度上决定着元搜索引擎的服务质量。为了实现搜索结果的有效整合,目前技术主要结合查询请求、文档内容、初始排序或（和）赋予搜索成员搜索引擎权重等因素。其中采用赋予搜索引擎权重时,往往根据用户和技术人员经验,主观地进行赋值,不能体现真实的用户搜索偏好。为此,提出了通过挖掘用户搜索及遍历情况,动态地赋予各成员搜索引擎权重的方法。通过用户遍历及点击下载情况,得到了用户搜索遍历与返回结果的匹配度,论证了该方法的可行性和有效性。     

动态矩阵控制中基于Kalman滤波的开环预测方法

用稳态Kalman滤波器来解释双层结构模型预测控制中的开环预测模块,得到的结果与非基于Kalman滤波导出的开环预测对应和等价.将该结果与文献中已有的Kalman滤波解释进行了详细对比,阐述了其中的不同点.针对双层结构预测控制的整体策略进行仿真,并针对积分输出的Kalman滤波进行仿真,验证了所得结论的有效性.     

多属性群决策权重调整自适应算法

研究多属性群决策中权重确定问题。对属性权重采用目标规划法进行优化;计算专家个体决策结果与群体决策结果的灰色关联度,据此对初始专家权重进行调整更新,进而调整更新初始群决策结果;根据2阶Minkowski距离继续对专家权重进行自适应调整,直至计算出稳定的专家权重和群决策结果。通过对风电机组设备供应商的评价表明了该方法的可行性与实用性。     

Some results on disturbance attenuation for Hamiltonian systems via direct discrete‐time design

The disturbance attenuation and robust disturbance attenuation problems for Hamiltonian systems in the discrete‐time setting are considered and some new results are presented. The new results are derived utilizing the recently presented dissipativity equality obtained by adding the dissipation rate function to the classical dissipativity inequality. A selection of the dissipation rate function yields new results. These results include a condition on the dissipation structure of the system to achieve the desired disturbance attenuation level and gives direct construction of optimal control laws for any desired disturbance attenuation level. The results remove the need to solve Hamilton–Jacobi–Isaacs inequalities. Copyright © 2014 John Wiley & Sons, Ltd.     

Distributed sediment yield modelling: Importance of initial sediment conditions

The importance of initial sediment conditions on model calibration and validation is analysed. A sediment model was calibrated and validated under three different initial sediment conditions: (0) no sediment availability, (1) calibration of the initial sediment condition and (2) using a warm-up simulation. The model results were assessed in terms of the graphic of fine sediment transport, or sedigraphs, and the visual fit of the hysteresis on the sediment rating.All strategies provided adequate results. However, the loop rating curve analysis demonstrated that the choice of initial sediment conditions affected the simulation results. Without any initial sediment condition, the model results were typically inferior to the simulation results with calibration or warm-up. The calibration of initial conditions proved to be the most reliable technique to generate clockwise hysteresis loops, but failed in reproducing other loop types. Overall, the warm-up simulations showed encouraging results, providing satisfactory fine sedigraph simulation results.     

Evaluating the Quality of Face Alignment without Ground Truth

The study of face alignment has been an area of intense research in computer vision, with its achievements widely used in computer graphics applications. The performance of various face alignment methods is often image‐dependent or somewhat random because of their own strategy. This study aims to develop a method that can select an input image with good face alignment results from many results produced by a single method or multiple ones. The task is challenging because different face alignment results need to be evaluated without any ground truth. This study addresses this problem by designing a feasible feature extraction scheme to measure the quality of face alignment results. The feature is then used in various machine learning algorithms to rank different face alignment results. Our experiments show that our method is promising for ranking face alignment results and is able to pick good face alignment results, which can enhance the overall performance of a face alignment method with a random strategy. We demonstrate the usefulness of our ranking‐enhanced face alignment algorithm in two practical applications: face cartoon stylization and digital face makeup.     

基于XML描述的数据挖掘结果的存储方法

对数据挖掘结果进行存储和维护能够提高数据挖掘效率并为共享挖掘结果提供更多的途径,为企业决策提供强有力的支持.对结构各异的结果模式进行存储首先需要一种表示半结构化信息的数据表示方法,而XML非常适合半结构化信息的描述.重点研究了以XML描述5种常见数据挖掘结果的方法,并提出了这5种数据挖掘结果的统一描述方法,为数据挖掘结果的集中存储、管理、利用以及共享奠定了基础.     

基于能量估计的灰度水印系统分析

针对一类灰度水印系统设计理论存在的不足,给出指导该类灰度水印算法设计的一系列理论结果,包括嵌入强度、鲁棒性、不可见性三者之间定量关系的建立,提出水印算法不可见性和鲁棒性的折中方案,采用已有的算法对理论结果进行验证,结果表明,得出的理论结果对该类水印算法的设计具有较大的指导意义。     

改进的无单元Galerkin方法在机场复合道面中的应用

运用改进的无单元Galerkin（Improved Element Free Galerkin,IEFG）方法计算机场复合道面的位移和应力,分析不同的节点数量和影响域比例参数对计算结果的影响.结果表明：节点数在4 000以上、影响域比例参数取2.5~3.5时计算结果较好;IEFG方法比无单元Galerkin(Element Free Galerkin,EFG)方法的精度更高,计算速度更快.计算结果可为机场道面设计提供参考.