Centros UC

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Browsing Centros UC by browse.metadata.fuente "Historial Académico"

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    Coping with Natural Disasters and Urban Risk: An Approach to Urban Sustainability from Socio-Environmental Fragmentation and Urban Vulnerability Assessment
    (Emerald Group Publishing Limited, 2014) Link, Felipe; Barth, Katrin; Harris, Jordan Michael; Irarrazaval Irarrazaval, Felipe; Valenzuela, Felipe; Welz, Juliane; William G. Holt; CEDEUS (Chile)
    Purpose - Cities have been exposed to a variety of natural disasters such as flooding, extreme temperatures, storms, earthquakes, and other natural shocks, and have had to respond and adapt to such pressures over time. In the context of global climate change, natural disasters have increased across the globe. Apart from climate change, many urban environments in Latin America are experiencing significant transformations in land use patterns, socio-demographic change, changing labor markets, and economic growth, resulting from recent decades of globalization. Such transformations have resulted in the internal fragmentation of cities. In this context, the purpose of the present chapter is to demonstrate the importance in both theoretical and methodological terms, of integrating the concept of socio-environmental fragmentation into urban vulnerability research in order to make progress toward higher degrees of local sustainability in those areas of the city that suffer natural disasters and fragmentation. Methodology/approach - A mixed methods approach is used in order to combine different technical issues from urban and climate change studies. Findings - The findings are related to the importance of an integrated approach, regarding the complexity of urban life, and the relationship between the urban, the social, and the environmental phenomenon. Social implications - This chapter relates to the revisit of the current state of preparedness and to determine whether further adaptations are required. The authors understood that these kinds of mixed approaches are necessary in order to understand the new complexity of urban processes.
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    Inequalities in job-related accessibility: Testing an evaluative approach and its policy relevance in Buenos Aires
    (2019) Vecchio, Giovanni; Lanza, Giovanni; Bocchimuzzi, Lucia; Pucci, Paola; CEDEUS (Chile)
    Accessibility, as a requisite to guarantee the individual ability to participate in valued activities, has been receiving increasing yet scattered attention from diverse theoretical and operational approaches. These approaches focus on how individuals are able to engage in out-of-home activities, participate in social life as well as on their involvement in other activities that contribute to their overall well-being. The paper aims at further investigating such approaches, analysing forms of inequality in job-related mobilities while assuming that a person's accessibility depends on both contextual and individual factors. Taking the Buenos Aires metropolitan area as a suitable testbed, the paper offers an approach to identify the inequalities in job-related accessibility at the neighbourhood scale. The approach considers the relationship between the quality and supply of public transport, level of social exclusion and reachable employment opportunities. The research proposes a synthetic index of inequalities in access to job opportunities (IAO) to identify disadvantaged urban areas characterized by a confluence of problems related to socio-economic deprivations, low accessibility to employment as well as a low mobility and poor quality of transport supply. The approach has an explicit operational dimension and intends to contribute to outlining tailored measures to guarantee better job opportunities, as in the case of people living in areas experiencing sub-standard levels of accessibility to workplaces.
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    Integrating Frequency Setting, Timetabling, and Route Assignment to Synchronize Transit Lines
    (2019) Giesen Encina, Ricardo; Knapp Dimonte, Paul Michael; Muñoz, Juan C.; Ibarra-Rojas, Omar; De Oña, Rocío; CEDEUS (Chile)
    Synchronization of different transit lines is an important activity to increase the level of service in transportation systems. In particular, for passengers, transferring from one line to another, there may be low-frequency periods and transfer zones where walking is needed, or passengers are exposed to adverse weather conditions and uncomfortable infrastructure. In this study, we define the Bus Lines Synchronization Problem that determines the frequency for each line (regarding the even headway), the timetable (including holding times for buses at transfer stops), and passenger-route assignments to minimize the sum of passenger and operational costs. We propose a nonlinear mixed integer formulation with time-indexed variables which allow representing the route choice for passengers and different types of costs. We implement an iterative heuristic algorithm based on fixing variables and solving a simplified formulation with a commercial solver. We implement our proposed heuristic on the transit network in Santiago, Chile. Numerical results indicate that our approach is capable of reducing operating costs and increasing the level of service for large scenarios.
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    The danger zone of express services: When increasing frequencies can deteriorate the level of service
    (Elsevier Ltd., 2020) Larraín Izquierdo, Homero; Muñoz Abogabir, Juan Carlos; CEDEUS (Chile)
    Express bus services are services that skip some of the stops along their routes to provide a faster ride for particularly demanded trips on a corridor. There is a growing literature on express services that focuses on route design and performance evaluation. In this work, we study a simplified transit corridor where a regular service operates in tandem with an end-to-end express service. Assuming that passengers minimize their expected travel and waiting times, we show that, even if the system has enough aggregate capacity, it may present a specific range of frequencies for the express service where it attracts more demand than it can actually fulfill. We call this range the "danger zone" of express services. When frequencies fall within the danger zone, a queue of passengers will form at the station. Applying queuing theory, we obtain expressions to estimate these queues and the associated waiting times, expected travel times and social costs of the system. We show that even when the station has unlimited passenger capacity, the performance of the system can be greatly affected in the danger zone. If the station has indeed limited capacity, the scenario can be much worse: if the queue grows to the point of saturating the station, a vicious circle ensues that amplifies the negative effects of the danger zone.