在静态编译器中实现Java异常机制的算法

将Java程序静态编译成可执行程序是使用Java虚拟机动态编译／解释执行Java程序的另一种运行Java程序的方式。针对Java异常机制的特点和静态编译的需求,在介绍Java异常处理逻辑的基础上,提出一种在静态编译器中实现Java异常机制的算法,结合Open64开源编译器,给出该算法的具体步骤以及实现方式,以SPECjvm98为测试集,验证该算法的有效性。     

Leveling up: Are non-gamers and women disadvantaged in a virtual world classroom?

Today's young gamers are tomorrow's students who expect more immersion from their online learning experiences. Teachers and administrators, however, must ask are some students at a disadvantage in such a class and does gender play a role? We examine the degree to which gaming experience and gender influence sense of presence in a virtual world learning classroom. Feelings of presence are key to involvement in virtual worlds. Participants, 348 undergraduates, interacted within a custom designed virtual world classroom focusing business negotiation skills. Results reveal that while gaming experience gives a slight advantage, lack of previous software ownership and gender do not put learners at a disadvantage. This finding shows that non-gamers and females can equally participate in a virtual world classroom, relieving concerns of adoption.     

A fuzzy reasoning and fuzzy-analytical hierarchy process based approach to the process of railway risk information: A railway risk management system

Risk management is becoming increasingly important for railway companies in order to safeguard their passengers and employees while improving safety and reducing maintenance costs. However, in many circumstances, the application of probabilistic risk analysis tools may not give satisfactory results because the risk data are incomplete or there is a high level of uncertainty involved in the risk data. This article presents the development of a risk management system for railway risk analysis using fuzzy reasoning approach and fuzzy analytical hierarchy decision making process. In the system, fuzzy reasoning approach (FRA) is employed to estimate the risk level of each hazardous event in terms of failure frequency, consequence severity and consequence probability. This allows imprecision or approximate information in the risk analysis process. Fuzzy analytical hierarchy process (fuzzy-AHP) technique is then incorporated into the risk model to use its advantage in determining the relative importance of the risk contributions so that the risk assessment can be progressed from hazardous event level to hazard group level and finally to railway system level. This risk assessment system can evaluate both qualitative and quantitative risk data and information associated with a railway system effectively and efficiently, which will provide railway risk analysts, managers and engineers with a method and tool to improve their safety management of railway systems and set safety standards. A case study on risk assessment of shunting at Hammersmith depot is used to illustrate the application of the proposed risk assessment system.     

Firms’ involvement in Open Source projects: A trade-off between software structural quality and popularity

Open Source (OS) was born as a pragmatic alternative to the ideology of Free Software and it is now increasingly seen by companies as a new approach to developing and making business upon software. Whereas the role of firms is clear for commercial OS projects, it still needs investigation for projects based on communities. This paper analyses the impact of firms’ participation on popularity and internal software design quality for 643 SourceForge.net projects. Results show that firms’ involvement improves the ranking of OS projects, but, on the other hand, puts corporate constraints to OS developing practices, thus leading to lower structural software design quality.     

An open implementation for context-oriented layer composition in ContextJS

Context-oriented programming (COP) provides dedicated support for defining and composing variations to a basic program behavior. A variation, which is defined within a layer, can be de-/activated for the dynamic extent of a code block. While this mechanism allows for control flow-specific scoping, expressing behavior adaptations can demand alternative scopes. For instance, adaptations can depend on dynamic object structure rather than control flow. We present scenarios for behavior adaptation and identify the need for new scoping mechanisms. The increasing number of scoping mechanisms calls for new language abstractions representing them. We suggest to open the implementation of scoping mechanisms so that developers can extend the COP language core according to their specific needs. Our open implementation moves layer composition into objects to be affected and with that closer to the method dispatch to be changed. We discuss the implementation of established COP scoping mechanisms using our approach and present new scoping mechanisms developed for our enhancements to Lively Kernel.     

Adoption of Open Source Software: The role of social identification

While the benefits of incorporating Open Source Software (OSS) into personal and organizational systems have been widely touted, OSS must be adopted and used by end users before these benefits can be realized. Drawing on research in information systems and sociology, this study develops and evaluates an integrated model for the acceptance of OSS. In addition to the traditional technology adoption variables the findings stress the importance of social identification as a key driver of OSS adoption. The proposed model provides a useful decision support tool for assessing and proactively designing interventions targeted at successful OSS adoption and diffusion.     

Diffusion dynamics of open source software: An agent-based computational economics (ACE) approach

The rising popularity of open source software (OSS) calls for a better understanding of the drivers of its adoption and diffusion. In this research, we propose an integrated framework that simultaneously investigates a broad range of social and economic factors on the diffusion dynamics of OSS using an Agent Based Computational Economics (ACE) approach. We find that interoperability costs, variability of OSS support costs, and duration of PS upgrade cycle are major determinants of OSS diffusion. Furthermore, there are interaction effects between network topology, network density and interoperability costs, which strongly influence the diffusion dynamics of OSS. The proposed model can be used as a building block to further investigate complex competitive dynamics in software markets.     

基于GL847的扫描图像校正

扫描仪在扫描成像过程中,诸多因素会给扫描图像带来误差和扭曲,因而必须对其加以校正。在分析扫描仪误差产生原理的基础上,详细讨论了基于GL847的扫描图像增益与偏移校正机制,提出了一种有效的扫描图像校正参数获取方法。     

GL Studio在武器装备虚拟训练系统中的应用

采用虚拟技术对武器装备操作人员进行训练是一种经济,高效的方法。针对武器装备系统结构复杂,精密性高等特点,选择开发周期短,界面真实感强的GL Studio软件来开发虚拟训练系统。探讨了武器装备虚拟训练系统设计开发流程和关键性技术。     

GIS互操作性初探

互操作性是ＧＩＳ发展的趋势,它实现窨数据和系统操作的共享。实现互操作性是ＧＩＳ用户的要求,万维网的发展为ＧＩＳ互操作性提供了技术基础。分布式空间数据模型和ＧＩＳ部件化是互操作笥ＧＩＳ的特征,Ｏｐｅｎ ＧＩＳ政致力于互操作性ＧＩＳ的空间标准。