15,192 research outputs found

    A Model of Regional Housing Markets in England and Wales

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    Balancing operating revenues and occupied refurbishment costs 1: problems of defining project success factors and selecting site planning methods

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    In planning the refurbishment of railway stations the spatial needs of the contractor and of the ongoing business stakeholders have to be balanced. A particular concern is the disruptive effect of construction works upon pedestrian movement. RaCMIT (Refurbishment and Customer Movement Integration Tool) was a research project aimed at addressing this problem. The objective of the research was to develop a decision protocol facilitating optimisation of overall project value to the client's business. This paper (the first of two) presents a framework for considering public disruption in occupied refurbishment using two case studies in large railway stations as examples. It briefly describes new tools which (combined with existing techniques) assist decision making in the management of disruption. It links strategic with sitebased decision making and suggests how public disruption may be treated as a variable to be jointly optimised along with traditional criteria such as time, cost and quality. Research observations as well as current literature suggest that for overall decision-making, opportunities may be lost (under current practice) for minimising joint project cost/revenue disruption, and, for spatio-temporal site decision-making, effective and efficient tools now exist to model both sides of the construction site boundary

    A Microsimulation Approach to the Modelling of Urban Population and Housing Markets Within an Object-Oriented Framework

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    The structure of a city constantly changes, in accordance to the population’s housing demand and the city’s housing supply. Housing demand depends on several factors, such as changes in household structure caused by demographic events (e.g. mortality, fer

    Fleet management in free-floating bike sharing systems using predictive modelling and explorative tools

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    For redistribution and operating bikes in a free-floating systems, two measures are of highest priority. First, the information about the expected number of rentals on a day is an important measure for service providers for management and service of their fleet. The estimation of the expected number of bookings is carried out with a simple model and a more complex model based on meterological information, as the number of loans depends strongly on the current and forecasted weather. Secondly, the knowledge of a service level violation in future on a fine spatial resolution is important for redistribution of bikes. With this information, the service provider can set reward zones where service level violations will occur in the near future. To forecast a service level violation on a fine geographical resolution the current distribution of bikes as well as the time and space information of past rentals has to be taken into account. A Markov Chain Model is formulated to integrate this information. We develop a management tool that describes in an explorative way important information about past, present and predicted future counts on rentals in time and space. It integrates all estimation procedures. The management tool is running in the browser and continuously updates the information and predictions since the bike distribution over the observed area is in continous flow as well as new data are generated continuously

    Modelling the response of vascular tumours to chemotherapy: A multiscale approach

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    An existing multiscale model is extended to study the response of a vascularised tumour to treatment with chemotherapeutic drugs which target proliferating cells. The underlying hybrid cellular automaton model couples tissue-level processes (e.g. blood flow, vascular adaptation, oxygen and drug transport) with cellular and subcellular phenomena (e.g. competition for space, progress through the cell cycle, natural cell death and drug-induced cell kill and the expression of angiogenic factors). New simulations suggest that, in the absence of therapy, vascular adaptation induced by angiogenic factors can stimulate spatio-temporal oscillations in the tumour's composition.\ud \ud Numerical simulations are presented and show that, depending on the choice of model parameters, when a drug which kills proliferating cells is continuously infused through the vasculature, three cases may arise: the tumour is eliminated by the drug; the tumour continues to expand into the normal tissue; or, the tumour undergoes spatio-temporal oscillations, with regions of high vascular and tumour cell density alternating with regions of low vascular and tumour cell density. The implications of these results and possible directions for future research are also discussed

    Drawing the line: balancing the spatial requirements of customer and contractor in occupied refurbishment

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    In planning the refurbishment of railway stations the spatial needs of the contractor and ofthe ongoing business stakeholders have to be balanced. A particular concern is thedisruptive effect of construction works upon pedestrian movement.RaCMIT (Refurbishment and Customer Movement Integration Tool) is a research projectaimed at addressing this problem through combining the knowledge of the client projectmanager, the construction planner and the pedestrian modelling expert.The objective of the research is to develop a decision protocol (based on problemsencountered in two case studies) facilitating optimisation of overall project value to theclient?s business.Research observations as well as current literature suggest that:? for overall decision-making, opportunities may be lost (under current practice) forminimising joint project cost/revenue disruption and? for spatial decision-making, temporary station configuration during construction(and not just overall pedestrian capacity) is a significant variable for both businessand safety outcomes. In planning the refurbishment of railway stations the spatial needs of the contractor and ofthe ongoing business stakeholders have to be balanced. A particular concern is thedisruptive effect of construction works upon pedestrian movement.RaCMIT (Refurbishment and Customer Movement Integration Tool) is a research projectaimed at addressing this problem through combining the knowledge of the client projectmanager, the construction planner and the pedestrian modelling expert.The objective of the research is to develop a decision protocol (based on problemsencountered in two case studies) facilitating optimisation of overall project value to theclient?s business.Research observations as well as current literature suggest that:? for overall decision-making, opportunities may be lost (under current practice) forminimising joint project cost/revenue disruption and? for spatial decision-making, temporary station configuration during construction(and not just overall pedestrian capacity) is a significant variable for both businessand safety outcomes

    Spatio-temporal Modelling of Accessibility to Train Stations for Park and Ride (PnR) Users

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    Accessibility has been of critical importance to physical planning over the past 60 years. This study mainly focuses a spatial methodology framework to understand measure and model the Park and Ride (PnR) users’ accessibility to train stations, specifically including the characteristics of catchment areas, directional accessibility to train stations, spatial modelling of train stations’ catchment areas, and spatio-temporal modelling of accessibility to train stations

    Geospatial Narratives and their Spatio-Temporal Dynamics: Commonsense Reasoning for High-level Analyses in Geographic Information Systems

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    The modelling, analysis, and visualisation of dynamic geospatial phenomena has been identified as a key developmental challenge for next-generation Geographic Information Systems (GIS). In this context, the envisaged paradigmatic extensions to contemporary foundational GIS technology raises fundamental questions concerning the ontological, formal representational, and (analytical) computational methods that would underlie their spatial information theoretic underpinnings. We present the conceptual overview and architecture for the development of high-level semantic and qualitative analytical capabilities for dynamic geospatial domains. Building on formal methods in the areas of commonsense reasoning, qualitative reasoning, spatial and temporal representation and reasoning, reasoning about actions and change, and computational models of narrative, we identify concrete theoretical and practical challenges that accrue in the context of formal reasoning about `space, events, actions, and change'. With this as a basis, and within the backdrop of an illustrated scenario involving the spatio-temporal dynamics of urban narratives, we address specific problems and solutions techniques chiefly involving `qualitative abstraction', `data integration and spatial consistency', and `practical geospatial abduction'. From a broad topical viewpoint, we propose that next-generation dynamic GIS technology demands a transdisciplinary scientific perspective that brings together Geography, Artificial Intelligence, and Cognitive Science. Keywords: artificial intelligence; cognitive systems; human-computer interaction; geographic information systems; spatio-temporal dynamics; computational models of narrative; geospatial analysis; geospatial modelling; ontology; qualitative spatial modelling and reasoning; spatial assistance systemsComment: ISPRS International Journal of Geo-Information (ISSN 2220-9964); Special Issue on: Geospatial Monitoring and Modelling of Environmental Change}. IJGI. Editor: Duccio Rocchini. (pre-print of article in press

    A GIS toolkit to evaluate individual and joint accessibility to urban opportunities

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