K. Weidenhaupt

Requirements elicitation and validation with real world scenes

A requirements specification defines the requirements for the future system at a conceptual level (i.e., class or type level). In contrast, a scenario represents a concrete example of current or future system usage. In early RE phases, scenarios are used to support the definition of high level requirements (goals) to be achieved by the new system. In many cases, those goals can to a large degree be elicited by observing, documenting and analyzing scenarios about current system usage. To support the elicitation and validation of the goals achieved by the existing system and to illustrate problems of the old system, we propose to capture current system usage using rich media (e.g., video, speech, pictures, etc.) and to interrelate those observations with the goal definitions. Thus, we aim at making the abstraction process which leads to the definition of the conceptual models more transparent and traceable. We relate the parts of the observations which have caused the definition of a goal or against which a goal was validated with the corresponding goal. These interrelations provide the basis for: 1) explaining and illustrating a goal model to, e.g., untrained stakeholders and/or new team members; 2) detecting, analyzing, and resolving a different interpretation of the observations; 3) comparing different observations using computed goal annotations; and 4) refining or detailing a goal model during later process phases. Using the PRIME implementation framework, we have implemented the PRIME-CREWS environment, which supports the interrelation of conceptual models and captured system usage observations. We report on our experiences with PRIME-CREWS gained in an experimental case study.

Scenario usage in system development: a report on current practice

Summary form only given. Scenario-based approaches are attracting more and more interest in requirements engineering research and practice. The research literature offers an increasing number of scenario-related methods, models and notations which highlight the consideration of concrete system descriptions from a usage-oriented perspective, prior to abstract conceptual modelling of function, data and behavior. Scenario use is also becoming a pervasive phenomenon in industrial practice, but comprehensive and expressive studies on the practical relevance of the techniques proposed by research are still rare. The European ESPRIT project CREWS (Cooperative Requirements Engineering With Scenarios) aims at a deeper understanding of the diversity of scenarios, in order to help improve methodological and tool support for scenario-based requirements engineering. The authors consider the two-pronged strategy being followed to gain this understanding.

PRIME—toward process-integrated modeling environments: 1

Research in process-centered environments (PCEs) has focused on project management support and has neglected method guidance for the engineers performing the (software) engineering process. It has been dominated by the search for suitable process-modeling languages and enactment mechanisms. The consequences of process orientation on the computer-based engineering environments, i.e., the interactive tools used during process performance, have been studied much less. In this article, we present the PRIME (Process Integrated Modeling Environments) framework which empowers method guidance through process-integrated tools. In contrast to the tools of PCEs, the process-integrated tools of PRIME adjust their behavior according to the current process situation and the method definitions. Process integration of PRIME tools is achieved through (1) the definition of tool models; (2) the integration of the tool models and the method definitions; (3) the interpretation of the integrated environment model by the tools, the process-aware control integration mechanism, and the enactment mechanism; and (4) the synchronization of the tools and the enactment mechanism based on a comprehensive interaction protocol. We sketch the implementation of PRIME as a reusable implementation framework which facilitates the realization of process-integrated tools as well as the process integration of external tools. We define a six-step procedure for building a PRIME-based process-integrated environment (PIE) and illustrate how PRIME facilitates change integration on an easy-to-adapt modeling level.

Calibrating the absolute amplitude scale for air showers measured at LOFAR

Air showers induced by cosmic rays create nanosecond pulses detectable at radio frequencies. These pulses have been measured successfully in the past few years at the LOw-Frequency ARray (LOFAR) and are used to study the properties of cosmic rays. For a complete understanding of this phenomenon and the underlying physical processes, an absolute calibration of the detecting antenna system is needed. We present three approaches that were used to check and improve the antenna model of LOFAR and to provide an absolute calibration of the whole system for air shower measurements. Two methods are based on calibrated reference sources and one on a calibration approach using the diffuse radio emission of the Galaxy, optimized for short data-sets. An accuracy of 19% in amplitude is reached. The absolute calibration is also compared to predictions from air shower simulations. These results are used to set an absolute energy scale for air shower measurements and can be used as a basis for an absolute scale for the measurement of astronomical transients with LOFAR.

A contextual approach for process-integrated tools

Research in process-centered environments (PCEs) has focused on project management support and has been dominated by the search for suitable process modelling languages and enactment mechanisms. The consequences of the process orientation on the tools used during process performance, and for offering fine-grained, method-based support to the engineers performing the process have been studied much less.

Improving reviews of conceptual models by extended traceability to captured system usage

Abstract When specifying change for an existing system, the history and functionality of the system to be replaced has to be considered. This avoids neglecting important system functionality and repeating errors. The properties and the rationale behind the existing system can be elicited by analysing concrete system-usage scenarios [Pohl, K., Weidenhaupt, K., Domges, R., Haumer, P., Jarke, M., Klamma, R., 1999. Process-integrated (modelling) environments (PRIME): foundation and implementation framework. ACM Transactions on Software Engineering and Methodology (TOSEM), vol. 8, no. 4, pp. 343–410]. The results of the analysis of the existing system are then typically represented using conceptual models. To establish conceptual models of high quality reviewing the models is common practice. The problem faced with when reviewing conceptual models, is that the reviewer cannot assess and therefore understand the basis (concrete system usage) on which the conceptual models were built. In this paper, we present an approach to overcome this problem. We establish Extended Traceability, by recording concrete system-usage scenarios using rich media (e.g. video, speech, graphic) and interrelating the recorded observations with the conceptual models. We discuss the main improvements for review processes and illustrate the advantages with excerpts from a case study performed in a mechanical engineering company.

A Process-Integrated Conceptual Design Environment for Chemical Engineering

The process industries (chemicals, food, oil, ...) are characterized by - - continuous or batch -- processes of material transformation. The design of such processes, and their mapping to the available equipment (plants composed of production units in which reactions take place), is a complex process that determines the competitiveness of these industries, as well as their environmental impact. In cooperation with researchers and industry from chemical engineering, we have developed the idea to capture and evaluate the experiences gained about process designs in so-called process data warehouses. The data sources for such process data warehouses are highly heterogeneous tools, e.g. for conceptual design (termed flowsheeting in chemical engineering), for mathematical simulations of large non-linear differential equation systems, for measurements gained with experimental usage of equipment at small scale or in original size, or even from molecular modeling. The clients of a data warehouse are interested in operational data transfer as well as experience analysis (pattern detection, process mining) and reuse. Starting from an empirical analysis of the requirements for a process data warehouse, the paper describes the solution architecture we are pursuing, the models driving the approach, and the status of a prototypical implementation we are undertaking. The prototype links commercial components operationally through advanced wrapping techniques, where the workflow is determined by constraint analysis in a logic-based meta model and executed through a process-integrated modeling environment. In the conclusions, we point out what can be learned from this work for conceptual modeling in general.

Using Developers' Experience in Cooperative Design Processes

The process industries are characterized by continuous or batch processes of material transformation with the aim of converting raw materials or chemicals into more useful and valuable forms. The design of such processes is a complex process itself that determines the competitiveness of these industries, as well as their environmental impact. Especially the early phases of such design processes, the so-called conceptual design and basic engineering, reveal an inherent creative character that is less visible in other engineering domains, such as in mechanical engineering. This special character constitutes a key problem largely impacting final product quality and cost. As a remedy to this problem, in cooperation with researchers and industrial partners from chemical and plastics engineering, we have developed an approach to capture and reuse experiences captured during the design process. Then, fine-grained method guidance based on these experiences can be offered to the developer through his process-integrated tools. In this section, we describe the application of our approach on the case study of the IMPROVE project. We first report on experiments made with a prototypical implementation of an integrated design support environment in the early project phases, and successively describe how it has been reengineered and extended based on additional requirements and lessons learned.

A Flowsheet-centered architecture for conceptual design

Publisher Summary This chapter discusses the flowsheet-centered architecture for conceptual design. The flowsheet-centered integration architecture is proposed that—in contrast to commercial solutions––takes into account the central role of flowsheets in chemical engineering design. A novel flowsheet editor has been realized as the center of such an architecture, which allows the creation and management of hierarchical flowsheets for various design alternatives in different versions on different levels of detail for a variety of applications in the design process. It has an open architecture for data exchange with application tools and is integrated with a coordinating workflow component. Integration with additional application tools is planned. A coupling of the flowsheet editor with administrative support systems for managing design processes in collaborative teams is described. Another focus will be laid on the visualization of data from different tools in the flowsheet for a better support of decisions.

A field study of data analysis exercises in a bachelor physics course using the internet platform VISPA

Bachelor physics lectures on particle physics and astrophysics were complemented by exercises related to data analysis and data interpretation at the RWTH Aachen University recently. The students performed these exercises using the internet platform VISPA, which provides a development environment for physics data analyses. We describe the platform and its application within the physics course, and present the results of a student survey. The students acceptance of the learning project was positive. The level of acceptance was related to their individual preference for learning with a computer. Furthermore, students with good programming skills favor working individually, while students who attribute themselves having low programming abilities favor working in teams. The students appreciated approaching actual research through the data analysis tasks.