Interactive situation models for systems development

Devising principles for systems representation and analysis that can cope with the complexity of the interactions between programmable components and human agents in modern computing applications is a challenging and fundamental problem. Understanding the role of human and inanimate components within a reactive system, for instance, involves not only input-output transformations, but also communication and stimulus-response issues. This paper proposes novel computer-based interactive situation models to assist systems development. Such models provide an environment within which the human interpreter can explore the relationships between observables and the patterns of behaviour associated with a system component with particular reference to its external real-world semantics. They are constructed using principles based upon observation, agency and dependency ("Empirical Modelling") that have been developed at the University of Warwick. This paper describes and illustrates ! the characteristics of interactive situation models in detail, and concludes with a brief discussion of their potential significance for systems development

Distributed empirical modelling and its application to software system development

Empirical Modelling (EM) is a new appro~h for software system development (SSO) that is particularly suitable for ill-defined, open systems. By regarding a software system as a computer model, EM aims to acquire and construct the knowledge associated with the intended system by situated modelling in which the modeller interacts with the computer model through continuous observations and experiments in an open-ended manner. In this way, a software system can be constructed that takes account of its context and is adaptable to the rapidly changing environment in which the system is developed and used. This thesis develops principles and tools for distributed Empirical Modelling (OEM). It proposes a framework for OEM by drawing on two crucial theories in social science: distributed cognition and ethnomethodology. This framework integrates cognitive and social processes, allowing multiple modellers to work collaboratively to explore, expand, experience and communicate their knowledge through interaction with their networked computer models. The concept of pretend play is proposed, whereby modellers as internal observers can interact with each other by acting in the role of agents within the intended system in order to shape the agency of such agents. The author has developed a tool called dtkeden to support the proposed OEM framework. Technical issues arising from the implementation dtkeden and case-studies in its use are discussed. The popular star-type logical configuration network and the client/server· communication technique are exploited to construct the network environment of this tool. A protocol has been devised and embedded into their communication mechanism to achieve synchronisation of computer models. Four interaction modes have been implemented into dtkeden to provide modellers with different forms of interpersonal interaction. In addition, using a virtual agent concept that was initially devised to allow definitions of different contexts to co-exist in a computer model, a definitive script can be interpreted as a generic observable that can serve as a reusable definitive pattern. Like experience in everyday life, this definitive pattern can be reused by particularising and adapting it to a specific context. A comparison between generic observables and abstract data types for reuse is given. The application of the framework for OEM to requirements engineering is proposed. The requirements engineering process (REP) - currently poorly understood - is reviewed. To integrate requirements engineering with SSD, this thesis suggests reengineering the REP by taking the context into account. On the basis of OEM, a framework (called SPORE) for the REP is established to guide the process of cultivating requirements in a situated manner. Examples of the use of this framework are presented, and comparisons with other approaches to RE are made

Explanatory models for open-ended human-computer interaction

Design principles to support human-computer interaction outside a closed-world framework are considered. These are based on the construction of explanatory models using Empirical Modelling tools and methods devised at Warwick. The approach can be applied to interaction that is associated with evolving understanding and the acquisition of skills on the part of the user. This is illustrated with reference to a study in mathematical investigation and visualisation, and the construction of a family of interactive models that can be used to teach the heapsort sorting algorithm

Interactive situation models for program comprehension

The complexity of the interactions between programmable components and human agents in modern computing applications motivates new approaches to program comprehension. Understanding the role of programs within a reactive system, for instance, involves not only input-output transformations, but also communication and stimulus-response issues. This paper examines the prospects for constructing novel computer-based interactive situation models to assist program comprehension. Such a model provides an environment within which the human interpreter can explore the data relationships and patterns of behaviour generated by a computer program with particular reference to its external real-world semantics. The proposed method of construction exploits principles based upon observation, agency and dependency ("Empirical Modelling") that have been developed at the University of Warwick. Connections between these principles and previous work on program comprehension are discussed. Some experimental studies in applying interactive situation models are reviewed, and conclusions about their potential future role in program comprehension and generation are drawn

Cultivating requirements in a situated requirements engineering process

The fact that requirements are situated motivates an alternative to conventional process models that gives adequate recognition to the situatedness of the requirements engineering process (REP). This paper proposes a problem-oriented framework SPORE (situated process of requirements engineering) whereby requirements as solutions to the identified problems in the application domain are developed in an open-ended and situated manner. Within this framework, people participating in the REP are able to cultivate requirements through collaborative interaction with each other for solving the identified problems, rather than to search for requirements from the jungle of users' needs. For a given application, a family of artefacts or interactive situation models (ISM) are developed which form the medium for the problem-solving process of requirements cultivation. These ISMs are built using the principles and tools of the Empirical Modelling, a novel approach to computer-based modelling. Participants can create and use these models not only as artefacts to explore, expand and experience the solutions to the identified problems, but also as a powerful means of supporting their collaborative interaction for 'growing up' the solutions in a distributed environment. A case study of applying this framework to cultivate requirements for a warehouse distribution system is given

Biomechanical Evaluation and Strength Test of 3D-Printed Foot Orthoses

Foot orthoses (FOs) are commonly used as interventions for individuals with flatfoot. Advances in technologies such as three-dimensional (3D) scanning and 3D printing have facilitated the fabrication of custom FOs. However, few studies have been conducted on the mechanical properties and biomechanical effects of 3D-printed FOs. The purposes of this study were to evaluate the mechanical properties of 3D-printed FOs and determine their biomechanical effects in individuals with flexible flatfoot. During mechanical testing, a total of 18 FO samples with three orientations (0°, 45°, and 90°) were fabricated and tested. The maximum compressive load and stiffness were calculated. During a motion capture experiment, 12 individuals with flatfoot were enrolled, and the 3D-printed FOs were used as interventions. Kinematic and kinetic data were collected during walking by using an optical motion capture system. A one-way analysis of variance was performed to compare the mechanical parameters among the three build orientations. A paired t-test was conducted to compare the biomechanical variables under two conditions: walking in standard shoes (Shoe) and walking in shoes embedded with FOs (Shoe+FO). The results indicated that the 45° build orientation produced the strongest FOs. In addition, the maximum ankle evertor and external rotator moments under the Shoe+FO condition were significantly reduced by 35% and 16%, respectively, but the maximum ankle plantar flexor moments increased by 3%, compared with the Shoe condition. No significant difference in ground reaction force was observed between the two conditions. This study demonstrated that 3D-printed FOs could alter the ankle joint moments during gait