Elastos跨进程跨语言对象调用的研究与实现

构件编程的目标是希望软件能够像积木一样轻松组装,这就需要构件模块做到高内聚低耦合,而将模块放在不同进程和用不同语言实现是实现高内聚低耦合的有效手段。因此,要实现构件编程,首先要解决对象的跨进程和跨语言调用。该文在Elastos构件编程的基础上提出了一种新的对象调用模型,使得不同进程、不同语言间的对象可以相互调用,并用测试数据证明了这种调用模型的可信性和高效性。     

基于梦境粒子群优化的类集成测试序列生成方法

类集成测试序列的确定是面向对象类集成测试技术中的一个重要课题。合理的类集成测试序列可以降低为其构造测试桩的总体复杂度,从而减小测试代价。针对粒子群优化算法容易早熟的缺陷,文中提出一种基于梦境粒子群优化算法的类集成测试序列生成方法。首先把每个类集成测试序列映射为一维空间中的一个粒子,然后将粒子看作有做梦能力的个体。每个迭代周期分为白天和夜间两个阶段,在白天阶段粒子正常移动,而在夜间阶段粒子根据各自的做梦能力扭曲当前位置。如此,粒子有机会在当前位置附近进行搜索,使得算法减缓收敛速度,避免过早陷入局部最优。实验结果表明,多数情况下该方法可以得到测试代价更小的类集成测试序列。     

Organising equity exchanges

In the past years equity exchanges have diversified their operations into business areas such as derivatives trading, post-trading services, and software sales. Securities trading and post-trading are subject to economies of scale and scope. The integration of these functions into one institution ensures efficiency by economising on transactions costs. Using balanced panel data from major equity exchanges over the period 2005–2008, we empirically analyse the effects of different business strategies on the costs per trade and the profitability of equity exchanges. The evidence confirms the existence of significant economies of scale. The evidence also shows that vertical integration increases the profitability of exchanges while diversification and horizontal integration reduces their profitability. Naturally, the increasing competition needs to be considered when analysing effects on profitability.     

一类离散线性切换系统的最优控制

研究了一类离散线性切换系统在切换时间、切换次数固定的情况下的二次最优控制问题.利用离散动态规划的方法,将多级决策过程分解成一系列易于求解的单级决策过程,求出最优控制序列和最优切换序列,并给出算法.最后通过一个数值例子来说明所提出的方法的有效性.     

一种用于类测试的改进型EFSM模型

扩展有限状态机(EFSM)中迁移存在前置条件和相应操作,而前置条件和相应操作中变量的相互依赖性导致了EFSM中存在不可达路径,不利于基于EFSM模型的类的测试。通过把UML状态图转换成EFSM模型,提出一种消除EFSM模型不可达路径算法,从而建立一种用于面向对象软件的类测试模型,通过该模型可以应用传统的数据流和控制流分析技术对类进行测试。     

Task Oriented Optimum Positioning of a Mobile Manipulator Base in a Cluttered Environment

A method for generating discrete optimal sequences of base locations for mobile manipulators is presented that considers the task capability of the workspace in a cluttered environment. In implementation, the obstacles and task trajectories are represented by 2ⁿ trees, so that a series of set operations are performed to characterize the manipulators configuration space into topological subspaces. By incorporating trajectory-motion-capable subspaces into the enumeration of the cost function, an optimum search technique is made applicable to the determination of a task feasible location. The method is then extended to a multiple positioning problem by concatenating the single optimization processes into a serial multistage decision making system, for which an optimal set of decisions can be found through a computationally efficient dynamic programming process.The computational paradigm of the present method is coherent with topological workspace analysis, and thus applicable to task trajectories of arbitrary dimensions and shapes. The effectiveness of the presented method is demonstrated through simulation studies performed for a 3-d.o.f. regional manipulator operating under various task conditions.     

Methodologies and tools for intelligent agents in distributed control

Agent technology also provides an appropriate framework to integrate knowledge with production actions. Knowledge integration depends on balanced information in and across organizations. So, replacing the central models with distributed intelligent agents make it possible to cope with demands more efficiently. In this, each agent represents a specific activity to support overall operations. With agents, maintaining the overall system is easier because instead of changes occurring to a colossal program, changes take place on a small scale without disrupting overall operations. We've developed a set of tools and methodologies to help design, build, test, and verify such systems. Using these tools and methodologies, we've devised an agent architecture that we've applied to a US Navy shipboard chilled-water system.     

Nash decomposition for process efficiency in multistage production systems

Many production systems consist of a sequence of processes or stages. For these systems, relational network DEA can be used and an overall system efficiency (equal to the efficiency of the different processes) can be computed. However, there can be alternative solutions that give different estimations of the process efficiencies and therefore lead to different decompositions of the overall system efficiency. It is not obvious which efficiency decomposition to use. In this paper, it is shown how a Nash bargaining game can be used to compute point estimates of the efficiency of the processes for multistage systems. The proposed approach extends and improves over existing approaches for production systems with just two stages. The rationality principles behind the proposed solution approach are presented and an interesting interpretation of the resulting efficiency decomposition is provided. The fact that this rigorous solution approach leads to such a simple and elegant efficiency decomposition should facilitate its adoption by Expert and Intelligent Systems practitioners.     

Framework of grinding process modeling and simulation based on microscopic interaction analysis

This paper describes a framework of grinding process modeling to understand the grinding fundamentals and design grinding processes with predictive performance. The model regards grinding process as a time dependent process and an integration of microscopic interactions in the wheel-workpiece contact zone, including cutting, plowing, and sliding as well as other frictional interactions. The grinding process control and design are in fact to manage and balance all these interactions. The principles of microscopic interactions are analyzed and used to correlate the grinding process input parameters and performance output.     

Accurate robotic belt grinding of workpieces with complex geometries using relative calibration techniques

Robotic belt grinding operations are performed by mounting a workpiece to the end effector and commanding it to move along a trajectory while maintaining contact with the belt grinding wheel. A constant contact force throughout the grinding process is necessary to provide a smooth finish on the workpiece, but it is difficult to maintain this force due to a multitude of installation, manipulation, and calibration errors. The following describes a novel methodology for robotic belt grinding, which primarily focuses on system calibration and force control to improve grinding performance. The overall theory is described and experimental results of turbine blade grinding for each step of the methodology are shown.     

Scheduling-Framework für Jobs auf parallelen Maschinen in komplexen Produktionssystemen

The paper describes a framework for parallel machine scheduling in complex manufacturing systems. Complex manufacturing systems are characterized by groups of parallel machines, machine dedications, sequence dependent setup times, batch processes, prescribed due dates of the jobs, and a diverse and over time changing product mix. In the present paper, a four-phase algorithm is suggested that covers a broad range of process conditions. The frameworks contains a first phase that deals with the formation of scheduling entities. The second phase is used to assign the scheduling entities to the parallel machines. The sequence of the scheduling entities is determined in the third phase on each single machine. The schedules are improved by the final, optional fourth phase. The paper describes software development issues, the integration of the framework into other information systems on the shopfloor, and the performance assessment of a case study.     

Coordination and control of batch-based multistage processes

Run-to-run (R2R) process control has attracted much attention in research and has been widely used in practice. It has been proved effective at compensating for process disturbances by using R2R controllers at a single stage. However, most manufacturing processes span across multiple stages; variation in earlier stages can be magnified stage by stage if they are not properly eliminated. In addition, products are processed batch by batch in certain manufacturing processes. In such cases, the traditional EWMA controller might not effectively reduce the variation. This paper focuses on developing a process control strategy for batch production in a multistage process. In the newly proposed framework, a batch-allocation operation is introduced to group products into similar clusters before each stage; an R2R controller is then implemented to generate customized recipes for each batch. This framework emphasizes better coordination among the stages in a multistage process. Simulation results show that the proposed strategy is effective for the reduction of variation.     

复杂时空域下多维度智能车间数据的关联网络建模

智能车间生产数据的多工序、跨流程、异构多态的特性加剧了生产过程中工艺数据关联融合问题的复杂性.面向复杂时空域下多维多尺度车间数据,提出一种基于时序聚类-关联挖掘-复杂网络的深度融合建模方法.首先,通过高斯核函数与一维卷积运算描述车间数据的聚类特征,采用欧氏距离度量车间时序数据特征向量间的相似性,并将处理后的时序特征引入聚类分析中;其次,通过时序数据关联规则提取各工艺参数之间蕴含的内在规律和关联关系,采用支持度与置信度完成关联规则的深度挖掘;然后,依据车间跨流程多工序协同运行特点,构建以多工序的工艺参数为节点、关联关系为边的带时间窗的生产工艺过程双权重有向多层网络模型,为车间跨流程、多工序、异构多态的工艺指标间的复杂关联关系的描述提供依据;最后,以某制丝生产线质量调控为例,对所提出方法的有效性和适用性进行验证.     

Understanding enterprise systems-enabled integration

A key touted benefit of enterprise systems (ES) is organizational integration of both business processes and data, which is expected to reduce processing time and increase control over operations. In our 3-year longitudinal case study of a phased ES implementation, we employed a grounded theory methodology to discover organizational effects of ES. As we coded and analyzed our field data, we observed many integration effects. Further analysis revealed underlying dimensions of ES-enabled integration. ES-enabled integration varied depending on the relationship between the integrated business units (similar plants, stages in a business process, or dissimilar functional areas) and on whether processes or data were integrated. Turning to the literature, we realized that Thompson's three types of interdependence, pooled, sequential, and reciprocal, captured the business relationships revealed in our data. Thus, we describe the salient characteristics of ES-enabled integration using Thompson's interdependence types applied to process and data integratio n. We also identify dimensions of differentiation between business units that contribute to integration problems. Viewing our field data through the lens of these salient characteristics and dimensions of differentiation provided theoretical explanations for observed integration problems. These findings also help managers understand and anticipate ES-enabled integration opportunities and problems.     

The Value of Outsourcing: A Field Study

This article examines the effects of information systems outsourcing on the business processes of organizations. Rather than simply comparing outsourcing and not outsourcing, the study also addresses a third and increasingly common strategy, that of using software purchased “off-the-shelf.” An extensive survey was distributed to business process managers over a cross-section of financial services processes and companies. Results show that outsourcing information systems can create lower overall process costs and may lead to superior overall process performance compared to processes that used software purchased off-the-shelf. Further, information systems built in house lead to superior overall process performance compared to processes that used software purchased off-the-shelf. These results should assist business managers in gauging the possible effects of outsourcing information systems (or not) on their core processes.     

Collaborative design: Managing task interdependencies and multiple perspectives

This paper focuses on two characteristics of collaborative design with respect to cooperative work: the importance of work interdependencies linked to the nature of design problems; and the fundamental function of design cooperative work arrangement, which is the confrontation and combination of perspectives. These two intrinsic characteristics of the design work stress specific cooperative processes: coordination processes in order to manage task interdependencies, establishment of common ground and negotiation mechanisms in order to manage the integration of multiple perspectives in design.     

Toward a more flexible Web-based framework for multidisciplinary design

In today's competitive environment, both industry and government agencies are under pressure to reduce the time and cost of multidisciplinary design projects. New tools have been introduced to assist in this process by facilitating the integration of and communication among diverse disciplinary codes. One such tool, a framework for multidisciplinary design, is defined as a hardware–software architecture that enables integration, execution, and communication among diverse disciplinary processes. An examination of current frameworks reveals weaknesses in various areas, such as sequencing, monitoring, controlling, and displaying the design process. The objective of this research is to explore how Web technology can improve these areas of weakness and lead toward a more flexible framework. This article describes a Web-based system that optimizes and controls the execution sequence of design processes in addition to monitoring the project status and displaying the design results.     

Improvements in land use mapping for irrigated agriculture from satellite sensor data using a multi-stage maximum likelihood classification

The accuracy of conventional land use classification of irrigated agriculture from optical satellite images using maximum likelihood supervised classification was compared with a classification based on multistage maximum likelihood supervised classification. In the multistage maximum likelihood classification series of sub-classifications were carried out which included masking and/or omitting certain crops from the classifications. These series of classifications improved the identification of individual crops/land use types. The output from the optimum sub-classifications were stacked to give an overall crop types/land use map. When the multistage classification was tested against a single stage classification on a large irrigation scheme in Central Asia the final accuracy of crop/land use classification increased from 85% to 94%. Field verification confirmed the accuracy at 93.5%. These results were achieved with a single Landsat 7 Enhanced Thematic Mapper (ETM+) sensor dataset as of 2 August 1999 over an area of 38.5?km².     

Understanding the functions of teleconferences for coordinating global software development projects

One of the dominant characteristics of contemporary software development is the global distribution of tasks, of developers, of information and of technologies. Undoubtedly, such distribution engenders new coordination challenges in the form of distance‐related interdependencies. One of the predominant processes of addressing these challenges is electronic meetings (or teleconferences). However, the functions of these meetings for coordination purposes are not yet understood. The distinctive conventions of teleconferences and their causal relationships that lead to optimal coordination of global software development (GSD) projects are also not yet understood. In this paper, the functions of teleconferences held by globally distributed software developers to coordinate their work in the face of global distribution of resources, cross‐site information interdependencies and continuously changing software requirements are analysed. The analysis is based on a qualitative study of how a subunit of 13 software developers, distributed across three sites in the USA and one in Republic of Ireland, used teleconferences to address its coordination challenges. The paper proffers a teleconference approach to GSD coordination by arguing that the functions of teleconferences manifest in software developers' multitasking; their ready access to all their information as additional benefits; flexibility in their communicative behaviours; and a reduction in their structure overload. This approach draws attention to these manifestations as distinctive conventions of the de‐structured meeting, which de‐structuring is occasioned by organic information processing needs in teleconferencing. This approach also explains why the combination of global distribution and teleconferences is a strategic opportunity for information processing for software process coordination.     

Rules for expanding robot applications

A discrepancy exists in the number of installed robot systems as compared to the number of potential applications. The restrictions of potential users in the seventies can be partially explained by the imperfect technology of the equipment and the minimal knowledge of first users with regard to robot integration into installed systems. Almost half of all installed robots are applied in the areas of spot and arc welding operations in the automotive industry. Due to the expected market saturation, robot manufacturers have to develop new applications for their products. These applications can be discovered through an analysis of the interdependencies between the requirements of respective tasks and the potential of new technologies. A systematic planning process is indispensable for a successful implementation.