Behavioral adaptation of information systems through goal models

Customizing software to perfectly fit individual needs is becoming increasingly important in information systems engineering. Users want to be able to customize software behavior through reference to terms familiar to their diverse needs and experience. We present a requirements-driven approach to behavioral customization of software systems. Goal models are constructed to represent alternative behaviors that users can exhibit to achieve their goals. Customization information is then added to restrict the space of possibilities to those that fit specific users, contexts, or situations. Meanwhile, elements of the goal models are mapped to units of source code. This way, customization preferences posed at the requirements level are directly translated into system customizations. Our approach, which we apply to an on-line shopping cart system and an automated teller machine simulator, does not assume adoption of a particular development methodology, platform, or variability implementation technique and keeps the reasoning computation overhead from interfering with the execution of the configured application.     

From fine-grained to abstract process models: A semantic approach

Organizations actively managing their business processes face a rapid growth of the number of process models that they maintain. Business process model abstraction has proven to be an effective means to generate readable, high-level views on business process models by showing coarse-grained activities and leaving out irrelevant details. In this way, abstraction facilitates a more efficient management of process models, as a single model can provide for many relevant views. Yet, it is an open question how to perform abstraction in the same skillful way as experienced modelers combine activities into more abstract tasks. This paper presents an approach that uses semantic information of a process model to decide on which activities belong together, which extends beyond existing approaches that merely exploit model structural characteristics. The contribution of this paper is twofold: we propose a novel activity aggregation method and suggest how to discover the activity aggregation habits of human modelers. In an experimental validation, we use an industrial process model repository to compare the developed activity aggregation method with actual modeling decisions, and observe a strong correlation between the two. The presented work is expected to contribute to the development of modeling support for the effective process model abstraction.     

Modeling NOx emissions from coal-fired utility boilers using support vector regression with ant colony optimization

Modeling NO_x emissions from coal fired utility boiler is critical to develop a predictive emissions monitoring system (PEMS) and to implement combustion optimization software package for low NO_x combustion. This paper presents an efficient NO_x emissions model based on support vector regression (SVR), and compares its performance with traditional modeling techniques, i.e., back propagation (BPNN) and generalized regression (GRNN) neural networks. A large number of NO_x emissions data from an actual power plant, was employed to train and validate the SVR model as well as two neural networks models. Moreover, an ant colony optimization (ACO) based technique was proposed to select the generalization parameter C and Gaussian kernel parameter γ. The focus is on the predictive accuracy and time response characteristics of the SVR model. Results show that ACO optimization algorithm can automatically obtain the optimal parameters, C and γ, of the SVR model with very high predictive accuracy. The predicted NO_x emissions from the SVR model, by comparing with the BPNN model, were in good agreement with those measured, and were comparable to those estimated from the GRNN model. Time response of establishing the optimum SVR model was in scale of minutes, which is suitable for on-line and real-time modeling NO_x emissions from coal-fired utility boilers.     

移动区域建模在Agent仿真中的应用

目前有关移动区域的应用不断增加,而传统的移动点模型已不能很好地适应移动区域的应用。为此,针对基于移动点Agent模型的局限性,提出一种新的基于移动区域的Agent模型,该模型结合新Agent技术及XML技术,将仿真运行过程中的Agent状态记录到移动对象XML数据库,以便于仿真回放和仿真事后分析。仿真实验结果证明了该模型的可行性。     

智能粮库曲面建模的设计与实现

在智能粮库计量系统中,粮面三维图形的还原与粮食质量的计算是粮库监管的一项重要内容．本系统采取将超声波传感器等设备非均匀地布置于粮仓内,用以获取粮面的部分信息,在合适的数学模型下还原出粮面的三维图形,并计算出粮食的体积和粮库的储粮质量,不仅能大幅度降低系统成本,而且具有安全、可靠、直观、高效等优点．     

一种快速三角形电源地平面谐振腔模型

针对等腰直角三角形平面模型效率低和精度差的问题,在双频点近似算法的基础上,提出了一种快速的Spice兼容等腰直角三角形平面谐振腔模型.与电感近似的等腰直角三角形平面模型相比,提出的模型使用最少的谐振腔基本模式与单节的高阶修正电路,不仅提高了等腰直角三角形电源地平面的仿真效率,而且改善了模型精度.仿真结果表明,电感近似模型在分类关键因子为2时,最大误差约为10%;提出的模型在分类关键因子为1.3时,最大误差约为1%,其仿真时间仅为电感近似模型的26%,验证了该模型在提高等腰直角三角形电源地平面的仿真效率和改善模型精度上的有效性.     

基于UML动态模型的数据操纵建模

针对传统数据建模过少关注对系统功能的实现建立模型的问题,在UML动态模型的基础上将界面交互模型与数据操纵过程相结合,并应用于数据操纵模型的构建中.该数据操纵模型从用户界面出发,用动态模型展现用户与系统的交互过程.实验证明,该方法能够降低软件维护的复杂性,提高软件的重用率,从而提高了软件开发过程效率和可维护性.     

炼钢-连铸生产调度系统建模

针对炼钢-连铸生产调度,通过扩展UML对象和消息传递机制,形式化捕述每个Agent的知识,并提升其行为控制和模块通讯能力;基于多Agent分布式建模体系,构造出炼钢-连铸生产调度系统所需的各种Agent类的静态属性和方法,及各类之间的动态交互关系,完成调度表生成、信息收集及数据分析处理,实现生产的有效调度．     

Investigation on the explosive welding mechanism of corrosion-resisting alu-minum and stainless steel tubes through finite element simulation and experi-ments

To solve the difficulty in the explosive welding of corrosion-resistant aluminum and stainless steel tubes, three technologies were proposed after investigating the forming mechanism through experiments. Then, a 3D finite element model was established for systematic simulations in the parameter determination. The results show that the transition-layer approach, the coaxial initial assembly of tubes with the top-center-point the detonation, and the systematic study by numerical modeling are the key technologies to make the explosive welding of LF6 aluminum alloy and 1Cr18Ni9Ti stainless steel tubes feasible. Numerical simulation shows that radial contraction and slope collision through continuous local plastic deformation are necessary for the good bonding of tubes. Stand-off distances between tubes (D1 and D2) and explosives amount (R) have effect on the plastic deformation, moving velocity, and bonding of tubes. D1 of 1 mm, D2 of 2 mm, and R of 2/3 are suitable for the explosive welding of LF6-L2-1Cr18Ni9Ti three-layer tubes. The plastic strain and moving velocity of the flyer tubes in-crease with the increase of stand-off distance. More explosives (R2/3) result in the asymmetrical distribution of plastic strain and non-bonding at the end of detonation on the tubes.     

板坯连铸中间包结构优化的研究

结合某公司双冲击点板坯中间包生产现状,利用水模实验对中间包内钢水流动特性进行了研究.结果表明：原中间包结构存在明显的短路流,钢水停留时间偏短,死区体积分率偏高,不利于夹杂物上浮去除.同时,由于在高度较大的两湍流控制器间钢水不能流出,影响金属收得率.这种具有双冲击点的中间包,应按照对称的两个单流板坯中间包进行结构优化.采用小高度湍流控制器加上下挡墙的控流方式时,由于钢水流经路径增长和全混流体积分率增加,响应时间增长,死区体积分率显著减小至15%以下,有利于夹杂物上浮去除.同时,将小高度湍流控制器和门式开孔导流坝相结合,残钢量显著减小,有利于提高金属收得率.