Reasons for bottlenecks in very large-scale system of systems development

ContextSystem of systems (SoS) is a set or arrangement of systems that results when independent and useful systems are to be incorporated into a larger system that delivers unique capabilities. Our investigation showed that the development life cycle (i.e. the activities transforming requirements into design, code, test cases, and releases) in SoS is more prone to bottlenecks in comparison to single systems.ObjectiveThe objective of the research is to identify reasons for bottlenecks in SoS, prioritize their significance according to their effect on bottlenecks, and compare them with respect to different roles and different perspectives, i.e. SoS view (concerned with integration of systems), and systems view (concerned with system development and delivery).MethodThe research method used is a case study at Ericsson AB.ResultsResults show that the most significant reasons for bottlenecks are related to requirements engineering. All the different roles agree on the significance of requirements related factors. However, there are also disagreements between the roles, in particular with respect to quality related reasons. Quality related hinders are primarily observed and highly prioritized by quality assurance responsibles. Furthermore, SoS view and system view perceive different hinders, and prioritize them differently.ConclusionWe conclude that solutions for requirements engineering in SoS context are needed, quality awareness in the organization has to be achieved end to end, and views between SoS and system view need to be aligned to avoid sub optimization in improvements.     

Applying a student modeling with non-monotonic diagnosis to Intelligent Virtual Environment for Training/Instruction

We present a student modeling approach that has been designed to be part of an Intelligent Virtual Environment for Training and/or Instruction (IVET). In order to provide the proper tutoring to a student, an IVET needs to keep and update dynamically a student model taking into account the student’s behaviour in the Virtual Environment. For that purpose, the proposed student model employs a student ontology, a pedagogic diagnosis module and a Conflict Solver module. The goal of the pedagogic diagnosis module is to infer which learning objectives have been acquired or not by the student. Nevertheless, the diagnosis process can be complicated by the fact that while learning the student will not only acquire new knowledge, but he/she may also forget some previously acquired knowledge, or he/she may have some oversights that could mislead the tutor about the true state of the student’s knowledge. All of these situations will lead to contradictions in the student model that must be solved so that the diagnosis can continue. Thus, our approach consists in applying diagnosis rules until a contradiction arises. At that moment, a conflict solver module is responsible of classifying and solving the contradiction. Next, the student ontology is updated according to the resolution adopted by the Conflict Solver and the diagnosis can continue. This paper mainly focuses on the design of the proper mechanisms of the student model to deal with the non monotonic nature of the pedagogic diagnosis.     

在线化工设备疲劳分析专家系统的研究

运用应力分析、疲劳分析的理论，综合专家学者的知识和经验，针对现代化大型联合企业技术管理的现状，提出了建立在线化工设备及管道安全评定中疲劳分析的专家系统方法，并编制了初级的软件。用简化试验来模拟一条高温高压蒸汽管线的疲劳裂纹扩展，并用之考评本软件。     

Development of refinery scheduling system using mixed integer programming and expert system

This paper presents a hybrid refinery scheduling system combining mathematical programming model and expert system. Mixed-integer linear programming models for crude oil movement between units are merged into the expert system that is for qualitative issues concerning crude vessel unloading operations. The target problem ranging from the crude unloading to the crude charging to distillation towers is decomposed into several module problems for efficiency. Compared with existing scheduling approaches for oil movement, the proposed hybrid refinery scheduling system is very effective in dealing with timing decisions involving vessel unloading operations due to the advantages of an expert system. Since the proposed scheduling system can generate solutions so fast, it is expected to play a key role in the real processes. This paper is dedicated to Professor Wha Young Lee on the occasion of his retirement from Seoul National University.     

高效快速纤维球过滤器的应用

介绍了纤维球过滤器的特点、工作原理及其在脱盐水装置中的应用效果。     

Jet bundle formulation of infinite-dimensional port-Hamiltonian systems using differential operators

We consider infinite-dimensional port-Hamiltonian systems described on jet bundles. Based on a power balance relation we introduce the port-Hamiltonian system representation using differential operators regarding the structural mapping, the dissipation mapping and the input mapping. In contrast to the well-known representation on the basis of the underlying Stokes–Dirac structure our approach is not necessarily based on using energy-variables which leads to a different port-Hamiltonian representation of the analyzed partial differential equations. The presented constructions will be specialized to mechanical systems to which class also the presented examples belong.     

Multivariable adaptive control: A survey

Adaptive control is a control methodology capable of dealing with uncertain systems to ensure desired control performance. This paper provides an overview of some fundamental theoretical aspects and technical issues of multivariable adaptive control, and a thorough presentation of various adaptive control schemes for multi-input–multi-output systems, literature reviews on adaptive control foundations and multivariable adaptive control methods, and related technical problems. It covers some basic concepts and issues such as certainty equivalence, stability, tracking, robustness, and parameter convergence. It discusses some of the most important topics of adaptive control: plant uncertainty parametrization, stable controller adaptation, and design conditions for different adaptive control schemes. The paper also presents a detailed study of well-developed multivariable model reference adaptive control theory and design techniques. It provides an introduction to multivariable adaptive pole placement and adaptive nonlinear control, and it concludes by identifying some open research problems.     

柳州,云浮,宣化三厂预热分解系统技术改进经验引起的思考

本文分析了柳州、云浮、宣化三厂预分解系统粘结堵塞、难以稳定生产和不能“达产达标”的原因,逐一介绍了三厂预分解系统技术改进的措施和效果,并就其技改工程经验进行了分析总结和探索思考.     

基于面向服务的泥石流数值模拟通用平台

对当前泥石流模拟系统的单一性缺点进行了研究,提出了面向服务的泥石流数值模拟的通用平台思想。以有限差分模型为基础,采用面向服务的思想,设计了系统 C/S模式的技术方案并完成了整个系统的设计和实现。经过香港滑坡地形图的验证,证明了本通用平台的可行性和有效性。     

注塑机的电液比例控制系统

本文介绍美国ＶａｎＤｏｒｎ塑机公司生产的５５吨注塑机的电液比例控制系统的组成，原理及特点；该系统集插装，负载传感功率匹配及计算机电液化比例控制等先进技术于一体，对国内新型注塑机的研究开发有一定参考价值，文末还就国内注塑机机械的制造和使用提出了建议。