A taxonomy of design methods process models

ContextDesigners and developers are increasingly expected to deliver high quality systems, i.e. systems that are usable, robust, consistent as well as evolutionary, and that fulfill users’ needs. To produce such systems, Design Methods suggest many approaches. However, the important number of existing approaches makes the choice of a method among the others particularly difficult. In addition to this, and because of the time required for understanding (and then operationalizing) new methods, designers tend to use already known methods, even though those which sometimes may not really be adapted to their needs.ObjectiveThis paper proposes a classification of characteristics of design methods process models. In other terms, it proposes a taxonomy that aims to facilitate the discovery and the choice of methods for designers and developers.MethodFrom a study of process models of several design methods, we identify six main axes, namely Cycle, Collaboration, Artifacts, Recommended Use, Maturity and Flexibility, which are in turn divided into 34 characteristics.ResultsThis paper provides a deep theorical insight. For each characteristic identified from relevant literature, a definition and a gradation, illustrated using examples, are given. Moreover, it presents a web site that offers various tools for exploring the axes of our taxonomy. This web site provides an overview of process models as well as means for comparing them, textually or graphically. Finally, the paper relates the first evaluation conducted in order to estimate designers’ adhesion to the taxonomy in terms of easiness of learning, completeness and intention to use.ConclusionWe show, based on evaluation results, that our taxonomy of process models facilitates the discovery of new methods and helps designers in choosing suitable methods, really adapted to their needs. Therefore, it enhances chances to conduct high quality projects.     

The software design studio: an exploration

Some software designers have recently turned for inspiration to the process of building design to improve development practices and increase software's usefulness and effectiveness. Architects' education revolves around the studio course, which promotes: project based work on complex and open ended problems; very rapid iteration of design solutions; frequent formal and informal critique; consideration of heterogeneous issues; the use of precedent and thinking about the whole; the creative use of constraints; and the central importance of design media. M. Kapor (1991) suggested that software practitioners needed to “rethink the fundamentals of how software is made” and proposed the architect's role in building design as a fruitful analogy for software professionals seeking to reform software practice. This analogy helps us focus on usefulness, usability, user needs and practices, and other technical and nontechnical aspects of good software design. It highlights concerns about people's lives and work practices and how people “inhabit” systems. Several authors have explored similarities and differences between software design and building design, including some who have pursued the software implications of architect Christopher Alexander's design patterns     

Needs’ elaboration between users,designers and project leaders: Analysis of a design process of a virtual reality-based software

ContextThe participation of users in the design process is recognized as a positive and a necessary element as artifacts suit their needs. Two complementary approaches of users’ involvement co-exist: the user-centered design and the participatory design. These approaches involve learning process from users to designers and vice versa. However, there has no research in design of virtual reality (VR)-based software dealing with how the elaboration of needs is actually distributed in time and among users, designers and project leaders, as well as how it is actually supported by tools and methods.ObjectiveThis paper aims to observe, in a real design project of a virtual reality-based software, how the various stakeholders (users, designers, project leaders) actually participate by sharing and pulling pieces of information from the process of needs elaboration, and how these contributions evolve throughout the decisions made in the course of the project.MethodOur method, based on the observation of the practices in collective design, allows us to collect and analyze the relationship between each possible action (e.g., elicitation), each stakeholder who initiates these actions (e.g., users) and each phase of the design process (e.g., evaluation phase), and the dynamics of the construction of needs.ResultsOur results detail how the elicited needs are dealt with by designers, users and/or project leaders: (1) we show a strong contribution of users in the design, compared to others stakeholders, (2) among the needs elicited by users, most have been validated by the designers, (3) some elicited needs could have been firstly rejected and finally validated and implemented.ConclusionWe identify the reasons which justify and explain our results confronting them to the literature. We underline the conditions have been satisfied in our study in order to involve effectively users in the design of emerging technologies.     

Planning and knowledge about strategies: Their relationship to work characteristics in software design

This paper describes an empirical study of software design processes in which both cognitive i.e. planning the work process, knowledge about strategies and organizational i.e. work characteristics factors were examined. Thirty-five software designers with an average professional experience of 6.6 years worked on a software design task in a laboratory setting. Thinking-aloud protocols were analysed, and additional interview and questionnaire data were gathered. It was found that software designers do very little explicit planning but have a broad knowledge of useful strategies. Results of regression analyses indicated that the amount of explicit planning and knowledge of strategies is predicted by the amount of design work to accomplish, communication and cooperation requirements, and control at work.     

A methodology to assess the impact of design patterns on software quality

Context

Software quality is considered to be one of the most important concerns of software production teams. Additionally, design patterns are documented solutions to common design problems that are expected to enhance software quality. Until now, the results on the effect of design patterns on software quality are controversial.

Aims

This study aims to propose a methodology for comparing design patterns to alternative designs with an analytical method. Additionally, the study illustrates the methodology by comparing three design patterns with two alternative solutions, with respect to several quality attributes.

Method

The paper introduces a theoretical/analytical methodology to compare sets of “canonical” solutions to design problems. The study is theoretical in the sense that the solutions are disconnected from real systems, even though they stem from concrete problems. The study is analytical in the sense that the solutions are compared based on their possible numbers of classes and on equations representing the values of the various structural quality attributes in function of these numbers of classes. The exploratory designs have been produced by studying the literature, by investigating open-source projects and by using design patterns. In addition to that, we have created a tool that helps practitioners in choosing the optimal design solution, according to their special needs.

Results

The results of our research suggest that the decision of applying a design pattern is usually a trade-off, because patterns are not universally good or bad. Patterns typically improve certain aspects of software quality, while they might weaken some other.

Conclusions

Concluding the proposed methodology is applicable for comparing patterns and alternative designs, and highlights existing threshold that when surpassed the design pattern is getting more or less beneficial than the alternative design. More specifically, the identification of such thresholds can become very useful for decision making during system design and refactoring.     

An adaptive design process generated by the integration of systematic design process and design patent protection mechanism

The conventional design processes are merely directed at measures for resolving problems, but fail to feature measures for procuring design patent protection. To overcome such a shortage, the authors have made a breakthrough by integrating the systematic design process (SDP) and design patent protection mechanism (DPPM) to develop an adaptive design process (ADP). The ADP includes 14 steps, as follows: (1) Problem, (2) Analysis, (3) Patent needs, (4) Concept, (5) Patent database searching, (6) Design database searching, (7) Integration, (8) Evaluation, (9) Decision, (10) Claim, (11) Solution, (12) Monitor, (13) Enforce and (14) Patent protection. In actual implementation, ADP allows designers to create novel creations easily and helps efficient procurement of design patent protection. In summary, ADP is a brand new design process with an advanced and effective nature.     

CAIRO: a concurrent engineering meeting environment for virtual design teams

This paper presents the software architecture for a next generation concurrent engineering environment that helps geographically separated designers and engineers to collaborate effectively. The paper highlights research in computer-supported collaboration work (CSCW) based on various models of group interaction, social communication theory, negotiation theory and distributed artificial intelligence concepts. The paper describes CAIRO (Collaborative Agent Interaction and synchROnization) system, a distributed conferencing architecture for managing designers and engineers in a distributed design meeting. The CAIRO system allows designers and engineers to work together in virtual teams by supporting multi-media interactions over computer networks. CAIRO aids the concurrent engineering effort by relaxing the physical, temporal and organizational constraints experienced in traditional design meeting environments. CAIRO provides both media synchronization, i.e. ensuring that all information exchanged between users is synchronized, and agent synchronization, i.e. ensuring effective structuring and control of a distributed conference. This paper also details the prototype CAIRO system with a detailed example, illustrating its use in concurrent design settings.     

Designing with dialogue charts: a qualitative content analysis of end-user designers' experiences with a software engineering design tool

Abstract. Software engineering tools used by designers are critical to most systems development methodologies, and successful methodologies are critical to improved productivity. However, the way in which designers use and relate to software engineering tools, whether computer assisted or not, has received little attention in the design literature. The purpose of this study is to gain insight into how people perceive the process of using design tools. The study is a qualitative analysis of interview information from participants in a field experiment. Four teams of student designers used various design tools during the development of interactive information systems typical of those that might be developed by sophisticated end-users. The research reported here is an exploratory study aimed at understanding how designers use one of these tools, the dialogue charts. The broad range of purposes included the uses predicted by the reference literature on design. However, the end-user designers also used the tool opportunistically — they found a broader range of tool usage than the literature on design tools predicted. For example, they consistently used the tool as a communications vehicle among different phases of design and development. The results show that the relationships these 'end-user designers' developed with the target tool are expressed in highly emotional language. These attitudes are tightly coupled with the purposes for which the designers use the tool. The methodology uses a field experiment as a treatment and a semistructured interview with a hidden agenda for gathering data. The data analysis techniques draw on the concepts of discovering grounded theory as described by Glaser and Strauss. They further draw on the concepts of qualitative content analysis synthesized by Krippendortf and the qualitative data analysis methods described by Miles and Huberman.     

The role of domain knowledge in software design

Abstract

If effective knowledge-based support is to be provided for software designers, the process of software design, and the classes of knowledge used by designers must be understood more clearly. It has been shown that a software designer's experience of designing software in the current application domain has a significant effect on the production of a quality design. However, in gaining experience of designing software, a designer gains knowledge in various distinct areas, including software design and the application domain. It is currently unclear which elements of this experience are important. In particular, the role of application domain knowledge that is independent of software design is of great significance for builders of intelligent software design support systems, since the overheads involved in providing application domain knowledge for a variety of application domains in such systems would be huge. This paper reports on a study that has been carried out to gain insights into this question, based around the structured techniques of DeMarco (1979) and Yourdon and Constantine (1979). From this preliminary investigation it would appear that a designer's general knowledge of the application domain does not affect the quality of a design produced for a system in this domain; this runs contrary to current popular beliefs.     

Fault tolerant embedded systems design by multi-objective optimization

The design of fault tolerant systems is gaining importance in large domains of embedded applications where design constrains are as important as reliability. New software techniques, based on selective application of redundancy, have shown remarkable fault coverage with reduced costs and overheads. However, the large number of different solutions provided by these techniques, and the costly process to assess their reliability, make the design space exploration a very difficult and time-consuming task. This paper proposes the integration of a multi-objective optimization tool with a software hardening environment to perform an automatic design space exploration in the search for the best trade-offs between reliability, cost, and performance. The first tool is commanded by a genetic algorithm which can simultaneously fulfill many design goals thanks to the use of the NSGA-II multi-objective algorithm. The second is a compiler-based infrastructure that automatically produces selective protected (hardened) versions of the software and generates accurate overhead reports and fault coverage estimations. The advantages of our proposal are illustrated by means of a complex and detailed case study involving a typical embedded application, the AES (Advanced Encryption Standard).     

A method and tool for the design of educational multimedia material

Abstract This paper deals with the problem of the specification of the pedagogic design of interactive multimedia and specific telematics applications developed for use in education. A method to specify the design and a supporting tool (SHOC-TOOL) are described. The idea is that the use of such a method and tool can make the development process more efficient and can lead to a more professional approach to the pedagogic design of educational software in general. Resulting design specifications can be assessed for completeness, allow for comparisons among designs and are relatively easy to read for others than the designer himself. The method and the tool both stimulate the re-use of existing design and code segments. SHOC-TOOL is described along with several examples from real practice. The paper concludes with a discussion of the experience of its introduction and use.     

Application of fuzzy logic in computer-aided VLSI design

Application of fuzzy logic structures in CAD of digital electronics substantially improves quality of design solutions by providing designers with flexibility in formulating goals and selecting tradeoffs. In addition, the following aspects of a design process are positively impacted by application of fuzzy logic: utilization of domain knowledge, interpretation of uncertainties in design data, and adaptation of design algorithms. We successfully applied fuzzy logic structures in conjunction with constructive and iterative algorithms for selecting of design solutions for different stages of the design process. We also introduced fuzzy logic software development tool to be used in CAD applications     

Systems scenarios: a tool for facilitating the socio-technical design of work systems

Abstract

The socio-technical systems approach to design is well documented. Recognising the benefits of this approach, organisations are increasingly trying to work with systems, rather than their component parts. However, few tools attempt to analyse the complexity inherent in such systems, in ways that generate useful, practical outputs. In this paper, we outline the ‘System Scenarios Tool’ (SST), which is a novel, applied methodology that can be used by designers, end-users, consultants or researchers to help design or re-design work systems. The paper introduces the SST using examples of its application, and describes the potential benefits of its use, before reflecting on its limitations. Finally, we discuss potential opportunities for the tool, and describe sets of circumstances in which it might be used.

Practitioner Summary: The paper presents a novel, applied methodological tool, named the ‘Systems Scenarios Tool’. We believe this tool can be used as a point of reference by designers, end-users, consultants or researchers, to help design or re-design work systems. Included in the paper are two worked examples, demonstrating the tool’s application.     

Multidisciplinary interface model for design of mechatronic systems

The design of mechatronic systems is based on the integration of several disciplines, such as mechanical, electrical and software engineering. How to achieve an integrated multidisciplinary design during the development process of mechatronic systems has attracted the attention of both academia and industry. However, solutions which can fully solve this problem have not been proposed by now. The concept of multidisciplinary interface represents the logical or physical relationship integrating the components of the mechatronic system or the components with their environment. As the design of mechatronic systems is a multidisciplinary work, the multidisciplinary interface model can be considered as one of the most effective supports to aid designers for achieving the integrated multidisciplinary design during the development process. The paper presents a multidisciplinary interface model for design of mechatronic systems in order to enable the multidisciplinary integration among design team members from different disciplines. On the one hand, the proposed model ensures the consistency of interface defined by the designers. On the other hand, it helps the designers to guarantee the different components integrate correctly. The interface model including three concepts: classification, data model and compatibility rules. The multidisciplinary interface model is implemented by a case study based on a 3D measurement system.     

Context-aware cognitive design assistant: Implementation and study of design rules recommendations

Design rules are an essential interface to facilitate the information exchange between designers and experts. Despite many innovations in Knowledge-Based Engineering and Knowledge Management, unstructured design rules documents are still widely used in the manufacturing industry. Due to the complexity of the design process, these documents often contain hundreds of design rules, applicable in varying design contexts. Searching for the right rules according to a design context is demanding in time and cognitive resources. In this paper, we propose a Context-Aware Cognitive Design Assistant (CACDA) to capture the design context and perform tasks such as the recommendation of design rules, the verification of design solutions, or the automation of design routines. Contrary to existing works in model quality testing, the CACDA uses a proactive approach of design rules application and helps designers to provide error-free designs on first attempt. In this paper, we present the design rules recommendation system of the CACDA, its capabilities and its implementation. Then, to measure the impact of design rules recommendations on the design process, we compare our approach with the use of traditional design rules documents. Results show that the use of the CACDA’s design rules recommendations lower the perceived difficulty of design rules retrieval from 75 to 43.5 on a scale of 100. On average, participants that used the demonstrator successfully applied 8.6 design rules on the 25 applicable design rules of our set. Participants that used unstructured documentation correctly applied 4.3 design rules. The global cognitive weight of the design activity as well as the design rules retrieval performances appear to be unchanged. These results demonstrate the usability of the demonstrator and show a positive impact on the design process and on the quality of CAD models. Future works will focus on the overcome of the main limitations of our current experiments, with a panel of professional designers, a lager design rules set and the implementation of several lacking features of the CACDA into the demonstrator.     

An ontology-based universal design knowledge support system

An effective and efficient knowledge support system is crucial for universal design process, as it has become a major design issue in the last decade with the growth of the elderly population and disabled people. There are a limited number of CAD investigations on the nature of knowledge processing that supports the cognitive activities of universal design process. Therefore, this paper proposes an ontology-based computer-assisted universal design (CAUD) plug-in tool that supports designers in developing satisfactory universal design solutions in the conceptual design phase. The required knowledge processing and representation of the developed tool is motivated by the ontological language. It is based on the multiple divergence–convergence cognitive strategies and cognitive needs of designers in the analysis/synthesis/evaluation operations. The CAUD plug-in tool is the first attempt to interface the universal design knowledge ontologically and respond to the requirements of conceptual design phase. According to the user acceptance study, the tool is assessed as useful, understandable, efficient, supportive and satisfactory.     

Improving the development of instructional software: Three building-block solutions to interrelate design and production

Currently, there is a focus on authentic tasks as the driving force for learning in integrated e-learning systems. This sets new criteria for instructional software, which should become much more flexible and allow for domain modeling and pedagogical modeling. A theoretical analysis and a survey (n = 37) amongst experienced developers show that current development methods are insufficient to develop such instructional software. New development methods such as “lean production” promise to satisfy the new criteria as they emphasize mass-customization by rigorously applying a pull-principle throughout the whole development process. However, a potential bottleneck is the lack of design languages to transfer the design outcomes to the production phase. Three building-block solutions are proposed to overcome this transition problem: (1) a 3D-model to support designers in stratifying, elaborating, and formalizing design documents, (2) instructional software templates to support designers in producing software themselves, and (3) an integrative approach to support designers in reusing learning objects.     

On facilitating knowledge transfer in software design

This paper presents a discussion of the facilitation of expertise sharing among software design stakeholders. LOUIS, a prototype research tool, helps to capture much of the contextual information and knowledge in early design meetings that are very often lost soon after the meetings are over. Using LOUIS as a basis, we consider knowledge and skill transfer effects in software design tasks. Results from trials indicate that, although not entirely sufficient, process-related knowledge, in the form of argumentation, is useful to software designers who have reason to re-use that knowledge. A list of recommendations on how those knowledge transfer effects can be further facilitated is provided.