支持虚拟企业的过程建模和工作流管理系统

针对虚拟企业提出了一种基于产品开发制造全过程分解和活动描述的形式化过程建模方法,在组成过程的任务中存在许多约束关系,如使能约束和促进约束,每个任务可以分解成许多活动,可以用企业本体论来表示这些活动、任务、状态和约束等,企业本体论是以情景演算来表示语义的,同时,建立了与过程模型相分离的组织模型活动、任务、状态和约束等,企业本体论是以情景演算来表示语义的。同时,建立了与过程模型相分离的组织模型;在此基础上,建立了一个工作流管理系统来支持虚拟的运行。文中提出一种由活动模型、意向模型、技能模型和伙伴模型等构成的Agent模型,来实现工作流管理,并通过构建可嵌套的Agent联帮增强系统的柔性。     

MPEC strategies for optimization of a class of hybrid dynamic systems

With the development and widespread use of large-scale nonlinear programming (NLP) tools for process optimization, there has been an associated application of NLP formulations with complementarity constraints in order to represent discrete decisions. In particular, these constraints arise frequently in equation-based formulations for real-time optimization. Also known as mathematical programs with equilibrium constraints (MPECs), these formulations can be used to model certain classes of discrete events and can be more efficient than a mixed integer formulation, particularly for large systems with many discrete decisions, such as dynamic systems with switches at any point in time. In this study, we consider and extend MPEC formulations for the optimization of a class of hybrid dynamic models, where the differential states remain continuous over time. These include differential inclusions of the Filippov type. Here, particular care is required in the formulation in order to preserve smoothness properties of the dynamic system. Results on three case studies, including process control examples, illustrate the effectiveness and accuracy of the proposed MPEC optimization methodology for a class of hybrid dynamic systems.     

Service Discovery and Negotiation With COWS

To provide formal foundations to current (web) services technologies, we put forward using COWS, a process calculus for specifying, combining and analysing services, as a uniform formalism for modelling all the relevant phases of the life cycle of service-oriented applications, such as publication, discovery, negotiation, deployment and execution. In this paper, we show that constraints and operations on them can be smoothly incorporated in COWS, and propose a disciplined way to model multisets of constraints and to manipulate them through appropriate interaction protocols. Therefore, we demonstrate that also QoS requirement specifications and SLA achievements, and the phases of dynamic service discovery and negotiation can be comfortably modelled in COWS. We illustrate our approach through a scenario for a service-based web hosting provider.     

基于体系结构的软件开发模型

传统软件开发模型存在开发效率不高,不能很好地支持软件重用等缺点。在多个大中型软件项目的实践基础上,提出了基于体系结构的软件开发模型(ABSD)。ABSD模型把整个基于体系结构的软件过程划分为体系结构需求、设计、文档化、复审、实现、演化等6个子过程,讨论了各个子过程所要完成的工作,给出了ABSD模型在劳动和社会保险领域的一个应用实例。实践表明,采用ABSD模型进行软件项目开发,具有结构清晰、易于理解、可移植性强、重用粒度大等优点。     

A simulated annealing approach to integrated production scheduling

This paper describes an approach to manufacturing planning that seeks to integrate both process planning and scheduling. We show that separating these two related tasks, as is the common practice, can impose constraints that substantially reduce the quality of the final schedule. These constraints arise from premature decisions regarding operation sequence and allocation of manufacturing resources. Having formulated an integrated process planning and scheduling problem, we describe a solution technique based on simulated annealing. We compare this approach with others reported in the literature, considering both their generality and performance. In particular, we perform a detailed empirical comparison between simulated annealing and the popular technique of dispatching rules. Our results, achieved with two distinct sets of example problems, show that simulated annealing can produce solutions of significantly higher quality than those achieved through a published dispatching rule approach.     

带时间和资源约束的实例化过程模型验证方法

软件过程的性能是由软件过程模型和软件过程实例化两方面因素决定,如果对软件过程进行了不恰当的实例化,会导致成本超支、进度延期、甚至项目失败．已有的过程描述法不足以分析实例化过程模型,由于没有考虑实例化阶段的时间资源约束,语法结构正确的过程模型并不能保证过程执行的正确性．提出一种带时间和资源约束的实例化过程模型验证方法,为目前已有的s-TRISO／ML建模语言增加时间和资源约束属性,然后提出了从s-TRISO／ML模型转换成时间自动机的转换方法和实现算法,利用已有的分析工具Uppaal对转换得到的时间自动机的性质进行验证,得到一个合理的实例化模型,从而为真实的开发流程提供指导．     

Guidelines for Business Rule Modeling Decisions

Business process models are used heavily in practice as a basis for process improvement, systems development, and understanding business operations. While prior research has identified a clear need for integrating business rules into graphical business process models, there is little guidance on the circumstances under which business rules should be integrated into business process models. Unnecessary integration may hamper business rule reuse, increase business process model complexity, and lead to difficulties with business rule modification, to name a few. Accordingly, it is important to understand when such integration is appropriate. The aim of this article is to address this need for guidance on when business rules should be integrated in process models, and when they should remain separate. To this end, we explain 12 factors posited to influence such modeling decisions, conduct an empirical study to identify their importance, and develop empirically based modeling guidelines that inform business rule modeling decisions.     

Implementation of set-based design in multidisciplinary design optimization

Set-based design is a design approach where feasible regions for the design variables are determined from different disciplines, with the goal of locating and working with the areas of feasible overlap. During the process the constraints are adjusted in order to accommodate conflicting requirements between disciplines. The main objective of set-based design is to narrow the design space, while delaying the pursuit of a single point design as much as possible. This process avoids finalizing decisions early and allows for flexibility in dealing with requirement creep. This paper presents the development and application of a new multidisciplinary design optimization (MDO) algorithm inspired by the principles of set-based design. The new MDO algorithm was developed with the core concept of describing the design using sets to incorporate features of set-based design and achieve greater flexibility than with a single-point optimization. The MDO algorithm was applied to a ship design problem and the ship design application demonstrated the value of utilizing set-based design as a space-reducing technique before approaching the problem with a point-based optimization. Furthermore, incorporating flexibility in the constraints allowed the optimization to handle a problem with very strict constraints in a rational manner and minimize the necessary constraint violation.     

基于事件约束的软件过程验证

软件过程是以人为中心的系统,其特点是动态性和不断演化.既定过程模型在实际执行时往往有所偏差.基于E-CSPE(extended constraints on succeeding and proceeding events)约束实现过程验证和偏差测量.事件约束根据过程模型定义.过程实例执行被记录为事件序列.通过分析事件序列对事件约束的覆盖和违反结果,可以计算EPD(event constraint based process difference metric)和EAD(event constraint based activity deviation metric)指标.EPD指标可以反映过程执行与过程模型的偏差,EAD指标则为过程演化提供依据.     

Dynamic Scheduling and Fault-Tolerance: Specification and Verification

Considera distributed real-time program which is executed on a systemwith a limited set of hardware resources. Assume the programis required to satisfy some timing constraints, despite the occurrenceof anticipated hardware failures. For efficient use of resources,scheduling decisions must be taken at run-time, considering deadlines,the load and hardware failures. The paper demonstrates how toreason about such dynamically scheduled programs in the frameworkof a timed process algebra and modal logic. The algebra providesa uniform process encoding of programs, hardware and schedulers,with an operational semantics of a process depending on the assumptionsabout faults. The logic specifies the timing properties of aprocess and verifies them via this fault-affected semantics,establishing fault-tolerance. The approach lends itself to applicationof existing tools and results supporting reasoning in processalgebras and modal logics.     

Predictive monitoring of temporally-aggregated performance indicators of business processes against low-level streaming events

Monitoring the performances of a business process is a key issue in many organizations, especially when the process must comply with predefined performance constraints. In such a case, empowering the monitoring system with prediction capabilities would allow us to know in advance a constraint violation, and possibly trigger corrective measures to eventually prevent the violation. Despite the problem of making run-time predictions for a process, based on pre-mortem log data, is an active research topic in Process Mining, current predictive monitoring approaches in this field only support predictions at the level of a single process instance, whereas process performance constraints are often defined in an aggregated form, according to predefined time windows. Moreover, most of these approaches cannot work well on the traces of a lowly-structured business process when these traces do not refer to well-defined process tasks/activities. For such a challenging setting, we define an approach to the problem of predicting whether the process instances of a given (unfinished) time window will violate an aggregate performance requirement. The approach mainly rely on inducing and integrating two complementary predictive models: (1) a clustering-based predictor for estimating the outcome of each ongoing process instance, (2) a time-series predictor for estimating the performance outcome of “future” process instances that will fall in the window after the moment when the prediction is being made (i.e. instances, not started yet, that will start by the end of the window). Both models are expected to benefit from the availability of aggregate context data regarding the environment that surrounds the process. This discovery approach is conceived as the core of an advanced performance monitoring system, for which an event-based conceptual architecture is here proposed. Tests on real-life event data confirmed the validity of our approach, in terms of accuracy, robustness, scalability, and usability.     

基于混合整数线性规划无人机实时航迹规划

为了解决无人机实时航迹规划问题,特别足带动力学约束条件的实时航迹规划问题,给出了基于混合整数线性规划技术在模型预测控制框架下进行无人机实时航迹规划的方法.通过将威胁区、速度、加速度以及威胁规避等约束条件转化为能够直接应用在MILP中的形式,并结合模型预测控制方法来进行规划以满足实时性要求.在威胁区的规避上,使用了二进制变量进行逻辑判断,同时,利用松弛变量的方法将威胁规避条件转变为线性形式;在速度、加速度约束条件上,使用单位圆将其约束在圆内以满足速度约束的限制.最后根据仿真计算的验证和分析,得出基于混合整数线性规划的无人机实时航迹规划的有效性.     

An integrated approach for requirement selection and scheduling in software release planning

It is essential for product software companies to decide which requirements should be included in the next release and to make an appropriate time plan of the development project. Compared to the extensive research done on requirement selection, very little research has been performed on time scheduling. In this paper, we introduce two integer linear programming models that integrate time scheduling into software release planning. Given the resource and precedence constraints, our first model provides a schedule for developing the requirements such that the project duration is minimized. Our second model combines requirement selection and scheduling, so that it not only maximizes revenues but also simultaneously calculates an on-time-delivery project schedule. Since requirement dependencies are essential for scheduling the development process, we present a more detailed analysis of these dependencies. Furthermore, we present two mechanisms that facilitate dynamic adaptation for over-estimation or under-estimation of revenues or processing time, one of which includes the Scrum methodology. Finally, several simulations based on real-life data are performed. The results of these simulations indicate that requirement dependency can significantly influence the requirement selection and the corresponding project plan. Moreover, the model for combined requirement selection and scheduling outperforms the sequential selection and scheduling approach in terms of efficiency and on-time delivery.     

Multi-level decision making in reconfigurable machining systems using fuzzy logic

Reconfigurable machine tools (RMTs) are synthesised using the principles of modular design in order to achieve the required structural design for a particular part to be manufactured. In this paper, an effective method that uses multi-level fuzzy decisions to create dynamic optimal configurations of machine structures with respect to a given part geometry is presented. A system of modular machine configuration is utilised to arrive at machine configurations considering the fuzzy constraints that are pertinent in this process. With the utilisation of fuzzy decisions for the configuration system model, selection of optimal modular tool configurations is done. Decisions are made at a particular threshold level so as to verify the appropriateness of such decisions.     

Security analysis of GTRBAC and its variants using model checking

Security analysis is a formal verification technique to ascertain certain desirable guarantees on the access control policy specification. Given a set of access control policies, a general safety requirement in such a system is to determine whether a desirable property is satisfied in all the reachable states. Such an analysis calls for the use of formal verification techniques. While formal analysis on traditional Role Based Access Control (RBAC) has been done to some extent, recent extensions to RBAC lack such an analysis. In this paper, we consider the temporal RBAC extensions and propose a formal technique using timed automata to perform security analysis by analyzing both safety and liveness properties. Using safety properties one ensures that something bad never happens while liveness properties show that some good state is also achieved. GTRBAC is a well accepted generalized temporal RBAC model which can handle a wide range of temporal constraints while specifying different access control policies. Analysis of such a model involves a process of mapping a GTRBAC based system into a state transition system. Different reduction rules are proposed to simplify the modeling process depending upon the constraints supported by the system. The effect of different constraints on the modeling process is also studied.     

Optimization of process route by Genetic Algorithms

Process route sequencing is considered as the key technology for computer aided process planning (CAPP) and is very complex and difficult. In this paper, based on the analyzing of various constraints in process route sequencing and the astringency of Genetic Algorithms (GAs), the GA is reconstructed, including the establishing of the coding strategy, the evaluation operator and the fitness function. The new GAs can meet the requirement of sequencing work and can meet the requirement of astringency. The natural number is adopted in coding strategy, the “elitist model” and the “tournament selection” are adopted as selection operators, the nonconforming sequential searching crossover operator is used and the inconsistent mutation operator is adopted, the fitness function is defined as a formula of the sum of compulsive constraints with each weighing, and these constraints are used as the control strategy for GAs in the searching process. By using GAs in the optimization, the optimal or near-optimal process route is obtained finally.     

Transition rather than balance: Organizing constraints for collective creativity in pharmaceutical development

When it comes to organizing for collective creativity, management scholars typically advise balancing between constraint and freedom. However, this suggestion to balance is often too enigmatic in practice, neglects the dynamics inherent in creative processes, and predominantly highlights the inhibiting aspects of constraints. Thus, the present article aims to rethink this balancing proposition by asking how constraints unfold during collective creative processes. Based on four cases of pharmaceutical development, it illustrates how collective creativity is enabled by constraints from two distinct sources, namely restraint and contingency. The article further shows how and why these constraint sources alternate along the development trajectory. While constraints can enable collective creativity, phases of constraint transition are eventually necessary to revitalize the development process. Building upon these findings, the article concludes that organizing constraints for collective creativity is a matter of transition rather than balance.     

Using an ethnographic process to conduct requirements analysis for agile systems development

Since the late 1990s, agile or lightweight software development methodologies have experienced a meteoric rise of interest among systems developers who consider traditional systems development methodologies (such as Structured Systems Development, Information Engineering, and Rational Unified Process) too inflexible for building systems having unpredictable and changing requirements. Agile methodologies try to adapt to rapid requirement changes by having short, iterative development cycles and by encouraging frequent, open communication with customers. However, agile methodologies are still in the process of devising systematic approaches on how to be adaptive to unpredictable and changing requirements and how to incorporate customers into the systems development process. In this study, we show how an ethnographic research process called Strip Resolution can be applied as a systematic complement to projects applying agile development principles. We illustrate, in detail, how the Strip Resolution Process (SRP) enabled us, in the role of systems developers, to adapt to changing and unpredictable user requirements and to incorporate customers into the systems development process.