ON COMPUTER SIMULATION AS A COMPONENT IN INFORMATION SYSTEMS RESEARCH

Computer simulation is widely regarded as a useful activity during various phases of research. However, depending on its context, the meaning, definition, and focus of the term can vary: In traffic planning, for example, simulation is used to determine useful configurations of a road network, thus focusing on the environment. An entirely different perspective is used within multi-agent systems. In such settings, the environment of the agents remains static, while the interesting research questions concern the behavior of the agents themselves. The research focuses on the microscopic level and the resulting emergent behavior. This article puts such diverse meanings in the context of a research process that treats descriptive and prescriptive research as two sides of the same coin. We develop a framework to classify different types of simulation, based on the actual research activity they are intended to be used for. Two case studies supplement the framework

Conservation of Limited Resources: Design Principles for Security and Usability on Mobile Devices

Mobile devices have evolved from an accessory to the primary computing device for an increasing portion of the general population. Not only is mobile the primary device, consumers on average have multiple Internet-connected devices. The trend towards mobile has resulted in a shift to “mobile-first” strategies for delivering information and services in business organizations, universities, and government agencies. Though principles for good security design exist, those principles were formulated based upon the traditional workstation configuration instead of the mobile platform. Security design needs to follow the shift to a “mobile-first” emphasis to ensure the usability of the security interface. The mobile platform has constraints on resources that can adversely impact the usability of security. This research sought to identify design principles for usable security for mobile devices that address the constraints of the mobile platform. Security and usability have been seen as mutually exclusive. To accurately identify design principles, the relationship between principles for good security design and usability design must be understood. The constraints for the mobile environment must also be identified, and then evaluated for their impact on the interaction of a consumer with a security interface. To understand how the application of the proposed mobile security design principles is perceived by users, an artifact was built to instantiate the principles. Through a series of guided interactions, the importance of proposed design principles was measured in a simulation, in human-computer interaction, and in user perception. The measures showed a resounding difference between the usability of the same security design delivered on mobile vs. workstation platform. It also reveals that acknowledging the constraints of an environment and compensating for the constraints yields mobile security that is both usable and secure. Finally, the hidden cost of security design choices that distract the user from the surrounding environment were examined from both the security perspective and public safety perspective

Development and application of a simulated urban system for geographical studies of environmental health

Urban areas are highly dynamic and diverse systems and the interactions and networks within an urban area are, at present, only partly understood, although some of the most important impacts on human health occur in these areas. It is essential, therefore, to develop a deeper understanding of these urban dynamics and processes especially with regard to exposure and health risk assessment. This thesis describes the development and application of an urban SImulation for ENvironmental health Analysis (SIENA). SIENA provides a controlled, simplified urban environment to develop and test spatial epidemiological concepts and models, to simulate processes and interactions relating to environmental exposure and to explore theoretical and methodological problems in the spatial analysis of environmental health. The development of the simulated urban system focuses on identifying and quantifying fundamental processes and inter-dependencies in the structure of urban areas in Great Britain. Twelve cities are chosen as sample cities and their spatial data structure (topography, transport network, land cover) and relationships between these structures and the urban population are statistically analysed. Based on the results of the statistical analysis SIENA is developed within a Geographic Information System (GIS) using probabilistic models and spatial analysis tools. Beside the identified core structure, topography, transport network, land cover and population, additional data such as traffic flow, air pollution monitoring networks or emissions from industrial sources amongst others are modelled and incorporated into SIENA. To demonstrate the potential of the simulation, SIENA is applied in two case studies both focusing on the misclassification of human exposure to urban air pollution. The first case study explores the representativeness of various air pollution monitoring networks and the resulting implications for exposure assessments. For the second case study, personal exposure is simulated within SIENA and then compared to the use of a location-based exposure proxy and the potential exposure misclassification spatially analysed