Functional system maps as boundary objects in complex system development

A trend towards the provision of product-service packaging and the proliferation of service businesses introduces both tangible and intangible elements into system design. In this paper, we consider the utility of hierarchical system models as a way of flexibly combining such elements by focusing on requisite functionality. Four cases illustrate how the same approach may be used to clarify the requirements of business or socio-technical systems during system development, operation or reengineering stages. It is suggested that a suitable loosely coupled model has significant utility as a 'boundary object' - a term first coined in the study of museum artefacts. Discussion of such objects requires the use of imagination, which may support innovative system design and development. It is suggested that a well-crafted model has multiple uses - as a foundation for system development, in combining traditional and agile project management strategies and in providing a framework to facilitate the capture and organisation of project knowledge.

Energy minimization in multi-task software-defined sensor networks

Abstract—
After a decade of extensive research on application-specific wireless sensor networks (WSNs), the recent development of information and communication technologies makes it practical to realize the software-defined sensor networks (SDSNs), which are able to adapt to various application requirements and to fully explore the resources of WSNs. A sensor node in SDSN is able to conduct multiple tasks with different sensing targets simultaneously. A given sensing task usually involves multiple sensors to achieve a certain quality-of-sensing, e.g., coverage ratio. It is significant to design an energy-efficient sensor scheduling and management strategy with guaranteed quality-of-sensing for all tasks. To this end, three issues are investigated in this paper: 1) the subset of sensor nodes that shall be activated, i.e., sensor activation, 2) the task that each sensor node shall be assigned, i.e., task mapping, and 3) the sampling rate on a sensor for a target, i.e., sensing scheduling. They are jointly considered and formulated as a mixed-integer with quadratic constraints programming (MIQP) problem, which is then reformulated into a mixed-integer linear programming (MILP) formulation with low computation complexity via linearization. To deal with dynamic events such as sensor node participation and departure, during SDSN operations, an efficient online algorithm using local optimization is developed. Simulation results show that our proposed online algorithm approaches the globally optimized network energy efficiency with much lower rescheduling time and control overhead.

A suite of visual languages for model-driven development of statistical surveys and services

Objective: To provide statistician end users with a visual language environment for complex statistical survey design and implementation. Methods: We have developed, in conjunction with professional statisticians, the Statistical Design Language (SDL), an integrated suite of visual languages aimed at supporting the process of designing statistical surveys, and its support environment, SDLTool. SDL comprises five diagrammatic notations: survey diagrams, data diagrams, technique diagrams, task diagrams and process diagrams. SDLTool provides an integrated environment supporting design, coordination, execution, sharing and publication of complex statistical survey techniques as web services. SDLTool allows association of model components with survey artefacts, including data sets, metadata, and statistical package analysis scripts, with the ability to execute elements of the survey design model to implement survey analysis. Results: We describe three evaluations of SDL and SDLTool: use of the notation by expert statistician to design and execute surveys; useability evaluation of the environment; and assessment of several generated statistical analysis web services. Conclusion: We have shown the effectiveness of SDLTool for supporting statistical survey design and implementation. Practice implications: We have developed a more effective approach to supporting statisticians in their survey design work.

A preliminary survey of factors affecting software testers

Most software testing research has focused on the development of systematic, standardised, and automated testing methodologies and tools. The abilities and expertise needed to apply such techniques and tools - such as personality traits, education, and experience - have attracted a comparatively small amount of research attention. However, the limited research in the area to date provides some indication that the human traits of software testers are important for effective testing. This paper presents the opinions of software testers themselves, collected through an online survey, on the importance of a variety of factors that influence effective testing, including testing-specific training, experience, skills, and human qualities like dedication and general intelligence. The survey responses strongly suggest that while testing tools and training are important, human factors were similarly considered highly important. Domain knowledge, experience, intelligence, and dedication, amongst other traits, were considered crucial for a software tester to be effective. As such, while systematic methodologies are important, the individual most clearly does matter in software testing. The results of our research have implications for education, recruitment, training and management of software testers.