Harvey J. Miller

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Hägerstrand’s time geography is a powerful conceptual framework for understanding constraints on human activity participation in space and time. However, rigorous, analytical definitions of basic time geography entities and relationships do not exist. This limits abilities to make statements about error and uncertainty in time geographic measurement and(More)
Geographic information systems (GIS) are convenient and potentially powerful platforms for transportation and urban analysis. Most GIS-based tools for transportation and urban analysis continue a place-based representation that is increasingly ill-suited to answer important questions in theory, policy and practice. The increasing disconnection between(More)
Key scientific and application questions concern the relationships between individual-level activities and their effects on broader human phenomena, such as transportation systems and cities. Continuing advances in geographic information science, location-aware technologies, and geosimulation methods offer great potential for observational and simulation(More)
Location-based services assist people in their decision-making during the performance of tasks in space. They do not consider the user’s individual preferences, time constraints, and possible subtasks to be performed. In order to account for these important aspects, a user centered spatio-temporal theory of location-based services is required. We propose(More)
Human lives consist of activities such as working, raising families, socializing, shopping and recreation. These activities require time and space, and are often only available at particular locations for limited durations. People differ with respect to the location and timing of key activities in their lives (e.g., home, work) as well as available time and(More)
This paper provides a decentralized and coordinate-free algorithm, called DGraF (decentralized gradient field) to identify critical points (peaks, pits, and passes) and the topological structure of the surface network connecting those critical points. Algorithms that can operate in the network without centralized control and without coordinates are(More)
Transportation systems exist to improve individual accessibility. However, emerging applications of GIS in transportation (GIS-T) and intelligent transportation system (ITS) focus on throughput (the amount of system flow) rather than accessibility. Throughput is related but not equivalent to accessibility. Sensitive transportation planning requires(More)