Structured design methods: how expert systems can help

The case study described in this chapter concerns the introduction of a new computer based integrated Clinical Information System (CIS) into a British National Health Services Trust-the Sunrise Trust. At the time of the study most of the system modules had been developed and were being tested largely for technical aspects. The system was being introduced during a period when the organization was experiencing significant changes. It was an environment where new structures were being created and the existing ones changed. Indeed, the case study was selected primarily because of these factors. The analysis of these structures, formal and informal, provides insight into the management of information systems. Various stakeholders in the Hospital Trust felt that a computer based information system would facilitate the change process. However the analysis and design of the system posed its own problems. The system turned out to be inflexible with respect to the core health care delivery process. It was also nonresponsive to the needs of the key stakeholders. Analysis of the case shows that clearly the formal methods adopted by the system analysts fell short of determining the rapid changes required for care. In particular this was an important issue, since the context of the British National Health Services posed pressures on individual trusts to be cost effective. This resulted in long term patients being moved out into the community. However, this richness in the context was overlooked by the analysts. They developed “logical” models of the system, which ended up in being “tidy pictures of reality” and were prescriptive and utterly inflexible. Structured Systems Analysis and Design Method (SSADM) was used as a modelling tool, which amplified the rational view of decision making and information technology (IT) applications (for more details on SSADM see Downs et al., 1988). The interpretations identified in the case show a clear mis-match between the formal models and perceptions of the system users who inevitably reflect a more informal and pragmatic approach to their own organizational realities. The analysis of the case poses a number of interesting issues. It questions the relationship between the complexity of the social relations and systems design. Furthermore it brings to the fore the paradoxical viewpoints of different stakeholders and the emergent concerns for a system analyst. The chapter also identifies the impact of an “overformalized” information system on the integrity of an organization. In doing so it evaluates the nature and significance of social power structures in systems analysis, design and implementation.

I worked for a British computer company in the 1990s, and it was company policy to use SSADM (Structured Systems Analysis and Design Method) for any new projects. At the time, we were working on a part of the London Underground (also called the Tube) automation. I went to my manager with the time estimate for a new module that I was designing. The estimate was high, and he asked, “What are all these tasks for gathering requirement specifications and technical system options?” I said those were SSADM-based tasks. He replied: “We can do the documentation later. Right now, get on with the database design and front-end development.” A lot of years later, that attitude has not gone away.

The reverse engineering into CASE technology method (RECAST) takes the source code for an existing COBOL system and derives a no-loss representation of the system documented in a structured systems analysis and design method (SSADM) format. One key element of the method is the abstraction of logical processing that affects the individual entities of the system. For each entity this processing is extracted from the physical implementation of the system using a program slicing technique and is then transformed into a logical representation (as an entity life history) using a set of translation and transformation rules. How the abstraction is achieved is described, and an example derived from an existing operational system that has been used as a case study for the method is given. >

Traditional structured analysis and design methods have been criticized because the methods lack formality to provide a design for rigorous development. Several approaches have been developed for verifying a design by integrating traditional structured analysis and design methods with formal specification languages. However, the integration of traditional structured analysis and design methods with formal specification languages may confuse the problem definition and understanding with the attempt to define system structures and algorithms in the design phase. In addition, formal specification languages may add complexity to the design due to the complexity of the language syntax and semantics. In this paper, we are presenting an approach to verification of a structured design in HOS without using formal specification languages. Rules for the partial and total correctness of the design are also discussed.

Unified Modeling Language (UML) plays an important role in the modern software development process by offering standardized methods for visual modeling, analysis, and design of complex systems. This paper discusses the main aspects of storing, editing, and integrating UML documents with integrated development environments (IDEs). The main focus is on comparing the two main formats for storing UML models – XML Metadata Interchange (XMI) and JavaScript Object Notation (JSON). XMI, being an official standard developed by Object Management Group, provides a high degree of detail and compatibility with various UML tools, making it preferable for large and complex projects that require support for the full UML specification. At the same time, JSON is simple and flexible, which makes it suitable for projects where speed of development and ease of integration are important, although it is inferior to XMI in describing complex aspects of UML models. The paper analyzes in detail the methods of editing UML documents, including manual editing and automated approaches, using APIs and scripts. Manual editing is useful when you need to make small changes to the structure of a UML document, but it can be time-consuming and error-prone when working with large projects. Automation, on the other hand, provides effective tools for mass editing and generating UML elements, which significantly speeds up development and minimizes the likelihood of errors, especially since modern tools such as StarUML offer the necessary tools for programmatically modifying UML documents by integrating them into development processes. Combining of UML documents with integrated development environments also plays a key role in increasing development efficiency, as this allows automating code generation based on UML models, maintaining synchronization between code and diagrams, and facilitating visualization and documentation of architectural solutions. Despite the significant advantages, there are challenges associated with limited support for all UML features and potential conflicts between models and code. This only emphasizes the need for further research in this area. Prospects for further research include the development of new methods and tools for working with UML documents, improving their integration with development environments, and using artificial intelligence to automate the analysis and design of UML models. Attention should also be paid to the using of UML with continuous integration processes, which can significantly increase the flexibility and adaptability of software development. Thus, the study of the structure of storing, editing, and integrating UML documents is an important area for optimizing the design and development of modern software systems.

This thesis presents a new modelling method for information systems analysis and design, where the concept of service and the principles of service orientation are used for integrated modelling and reasoning about information systems architectures across organisational and technical systems boundaries. The concept of service enables cohesion of the intersubjective and objective modelling traditions by using a single type of diagram that facilitates detection of semantic inconsistency, incompleteness, ambiguity and discontinuity between the static and dynamic aspects of information systems specifications. The thesis is focused on three research topics, which are fundamental to the development of a new service-oriented modelling method. The first research topic concerns a pragmatic-driven specification of information systems. It clarifies answers to the research question: How can a conceptual modelling process be driven by pragmatic considerations? The second research topic provides a service-oriented modelling foundation for information systems analysis and design. It answers the research questions: How can the concept of service be used explicitly for the analysis and design of information systems and how can the static and dynamic aspects of information systems specifications be integrated at the conceptual level? The third research topic presents transition principles to implementation-specific design and answers the research question: How can service-oriented conceptual representations be aligned with implementation-specific design? The thesis contributes with a new knowledge to the area of conceptual modelling of information systems. The service-oriented modelling method consists of the modelling process, modelling language and techniques for the analysis and design of information systems on three levels of abstraction: pragmatic, semantic and syntactic. These three levels are necessary for a holistic understanding of enterprise architecture by stakeholders. The advantage of the service-oriented modelling method is that it can help to control traceability from information system design to original requirements. The method facilitates the semantic integration of the structural, behavioural and interactive aspects of information systems conceptual representations by using a single diagram type. The modelling language provides service-oriented constructs that are fundamental to building the major systems analysis patterns. The service-oriented modelling process contributes with seven steps of incremental design, which justifies various information systems components. The method provides the basis for a gradual and systematic way of modelling and an understanding of how pragmatic, semantic and logical information system requirements are linked together. The possibility to detect and eliminate undesirable characteristics of service-oriented diagrams can help to improve communication among stakeholders. Service-oriented specifications are computation-neutral and therefore they are more comprehensible for business analysis experts in comparison to implementation specific graphical representations of information systems. Finally, this thesis presents the challenges for future research, one of which is the development of the automated tools for the alignment of business models with implementation-specific information systems specifications.

Structured design with mathematical proofs

Although many information systems (IS) design methods and techniques are available to IS professionals, none of them completely supports the design process. One of the problems is that there is a mismatch between IS design method; and the system to be built. Actually, in designing an IS, the methods or techniques employed should match the types and characteristics of the system to be built. Thus paper will explore the relationship between IS types/characteristics and systems design methods, and provide IS designers with a systems framework to develop methods or techniques that match the types and characteristics of IS.

The papers in this special section examine modeling and simulation methods for the analysis and design of advanced energy conversion systems. Energy conversion lies aEnergyveral fronts including materials, conversion methods, power electronics, and controls have created new opportunities for efficient energy conversion from both the conventional and new sources of energy. Our urgent need to solve many critical problems with regards to the sustainability and security of our energy system as well as the ever-increasing environmental challenges facing humanity have further spurred unprecedented opportunities for creation of innovative solutions to address these challenges.

The computational cost of reliability analysis and optimization of medium/large structural systems is prohibitively high. One of the reasons for this situation is the use of inefficient methods, such as finite differences, for design sensitivity analysis. A significant increase in the efficiency of reliability computations is expected from the integration of reliability methods with the discrete and continuum methods of design sensitivity analysis. So far, only the discrete method has been used in the so-called stochastic finite element method. Integration of reliability computations with the continuum method of design sensitivity analysis is proposed in this paper as a new, powerful approach to the probabilistic design of large structural systems. Basic formulations and solution methods of reliability analysis, design sensitivity analysis of reliability indices, reliability-based optimization, and multiobjective reliability-based optimization are reviewed with focus on the sensitivity informatio...

Autosub is a project funded by the Natural Environment Research Council in the UK, with the aim of developing unmanned autonomous underwater vehicles to carry out long range scientific missions in the deep ocean. The navigation system is critical to the survival of the vehicle, and so it is important that appropriate software engineering methods are used. Structured analysis and design methods are useful in helping to capture the requirements of the system, and in producing a well structured design that encourages re-use of code and data. This is necessary but not sufficient. We must also address implementation issues such as multi-tasking, sharing of hardware resources, and message passing and testing. The author describes the methods that he has used in developing the navigation system and gives a personal account of the problems that he has encountered.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Recent theoretical developments have improved the understanding of gain scheduled control and suggested new methods for design, analysis and implementation of such nonlinear control systems. An integrated software environment for gain scheduled local controller network design and analysis, including computer-aided modelling and system identification, is described. Some background theory is included, and a speed control design problem for an experimental vehicle illustrates the application of the approach.

Quasilinear Control (QLC) is a set of methods for analysis and design of systems with nonlinear actuators and sensors. The approach of QLC is based on the method of stochastic linearization, which replaces each nonlinearity with an equivalent gain and bias. In this chapter, we revisit the wind farm controller from Chap. 4 and apply QLC to the design of the proportional controller gains on its inner feedback loop. QLC is particularly suitable here because each of the wind turbines can be modeled as a linear plant preceded by an asymmetric saturation nonlinearity, which accounts for the limited availability of wind. Through extensive numerical simulation, we show that controller gains designed using QLC perform significantly better in a broad range of wind farm operating regimes, compared to those designed using traditional linear methods, where the asymmetric saturation nonlinearities are ignored. The operating regimes we consider include regimes with low and high wind speed, medium and high power generation, weak and strong wind correlation, and cheap and expensive control.

The paper presents a method of engineering analysis and design for complex control systems, the time-domain infinite-matrix method. The formulation of the infinite matrix follows from the convolution summation of sampled-data systems. The mathematical basis of the time-domain matrix formulation is related to the applicable concepts of infinite matrices and sequence spaces. The method is applicable to both continuous-data and sampled-data systems. For continuous systems it is necessary to introduce a fictitious sampler and `hold? of sufficient sampling rate to effect an accurate approximation. The time-domain-matrix method is presented and illustrated as a method of analysis and design of linear, non-linear, and time-varying systems of the continuous-data or sampled-data class. The investigation of non-linear systems is greatly simplified by the time-domain approach. Multi-loop systems may be investigated, and the signals at intermediate points throughout the loops are readily available. Also, systems with multiple non-linearities may be investigated. Two methods of design of a discrete compensator for a sampled-data system are presented. These methods are accomplished directly in the time domain and allow for a compromise of specifications in the time domain. In one design procedure the response between sampling instants is also accounted for. The time-domain-matrix method may be readily programmed on a digital computer, and therefore provides a rapid analysis and design technique.

Mechanical design is one of the essential disciplines in engineering applications, while inspirations of design ideas highly depend on the ability and prior knowledge of engineers or designers. With the rapid development of machine learning (ML) techniques, artificial intelligence (AI)‐based design methods are promising tools for the design of advanced engineering systems. So far, there have been some studies of 2D patterns and structural designs based on ML techniques. However, a particular challenge remains in allowing complex 3D mechanical designs using ML techniques. Herein, a novel and experience‐free method to equip ML models with 3D design capabilities by combining a convolutional neuron network (CNN) with a deep convolutional generative adversarial network (DCGAN) is developed. The model directly receives 2D image‐based training data that define the complex 3D structures of a specific machine part. After the training process, an infinite number of new 3D designs can be generated by the proposed model, with their geometric and mechanical properties being accurately predicted at the same time. Moreover, the generated new designs can be fed back to expand the original input datasets for further ML model training and updating.