DYNAMIC DISCRETE CHOICE MODELS FOR CAR OWNERSHIP MODELING

With the continuous and rapid changes in modern societies, such as the introduction of advanced technologies, aggressive marketing strategies and innovative policies, it is more and more recognized by researchers in various disciplines from social science to economics that choice situations take place in a dynamic environment and that strong interdependencies exist among decisions made at different points in time. The increasing concerns about climate change, the development of high-tech vehicles, and the extensive applications of demand models in economics and transportation areas motivate this research on vehicle ownership based on disaggregate discrete choices. Over the next five to ten years, dramatic changes in the automotive marketplace are expected to occur and new opportunities might arise. Therefore, a methodology to model dynamic vehicle ownership choices is formulated and implemented in this dissertation for short and medium-term planning. In the proposed dynamic model framework, the car ownership problem is described as a regenerative optimal stopping problem; when a purchase is made, the current vehicle state (vehicle age, mileage driven, etc.) is regenerated. The model allows the estimation of the probability of buying a new vehicle or postponing this decision; if the decision to buy is made, the model further investigates the vehicle type choices. Dynamic models explicitly account for consumers' expectations of future vehicle quality or market evolution, arising endogenously from their purchase decisions. Both static and dynamic formulations are applied first to simulated data in order to test the ability to recover the true underlying parameters of the synthetic population. Results obtained attest that the dynamic model outperforms the static MNL in terms of goodness of fit, parameters bias and predictive power. In particular, it is found that MNL captures the general trends in choice probabilities, but fails to recover peaks in demand and behavioral changes due to rapidly evolving external conditions. The extension to a real case study required a data collection effort. A preliminary pilot survey was designed and executed in the State of Maryland in fall 2010; the survey was self-administrated and web-based. Choices were made under the hypothesis that an interval time period of six months passed from a decision to the successive decision and choices over a hypothetical time period of six years were recorded. Finally, the application of dynamic discrete choice models to vehicle ownership decisions in the context of the introduction of new technology is proposed. Results from the real case study confirm our initial expectations, as the model fit is significantly superior to the fit of the static model

European research projects on Urban agriculture

Los trabajos reunidos en los números 6 y 7 de la revista Hábitat y Sociedad dejan claro que hay una atención creciente en la investigación hacia la agricultura urbana y periurbana, así como hacia políticas públicas que fomentan y regulan estas formas de uso del suelo urbano. Este creciente interés por la agricultura urbana y las políticas públicas que la ordenan se enmarca dentro del desarrollo más amplio de nuevas estrategias urbanas para fortalecer sistemas alimentarios más sostenibles y resilientes. Esta creciente atención también se puede percibir en el ámbito europeo e internacional donde están surgiendo proyectos de investigación y conferencias internacionales donde la agricultura urbana y periurbana es objeto de un especial interés. En esta contribución se exponen los principales proyectos europeos de investigación y algunas de las conferencias internacionales recientes más relevantes, apuntando los temas propuestos para el debate y los enfoques aplicados para el análisis

Environmental co-operatives reconnect farming, ecology and society

Regional diversity, diversified farming styles and endogenous development are hot issues in the current political debate on European agriculture. This article presents a historical overview of development experiences and elaborates on the emergence of environmental co-operatives in Dutch farming. They are unique ‘field laboratories’ for innovations toward sustainable rural development. The achievements in terms of environmental gains and social cohesion are coupled with cost reduction for the farmers and the stat

Collective Farmers Marketing Initiatives in organic supply chains – relevance, barriers and support strategies

Conclusions - New forms of collective farmers’ marketing that go beyond traditional cooperative mechanisms can be observed across Europe - These can be understood as responses to changing market, policy and societal contexts: -- Loss of control over supply chains due to dominant position of retailers and concentration in retailing & processing -- Increased production / processing standards -- Growing differentiation of rural areas, evolving urbanrural relations, and changes in EU rural policy frameworks new opportunities -- New markets for distinctive food qualities, services & public goods - Collective organic farmers’ marketing initiatives apply a diversity of strategies ­ sometimes in combination ­ that are crucial to understand their functioning and (potential) impact

Between food ethics, solidarity and the social construction of alternative markets. Exploring the dimensions of grassroots food movements in Spain

In recent years there has been growing attention for the emergence of alternative food networks, first as a possible strategy for farm households to counter deteriorating market conditions and respond to changing societal demands, and more recently as expression of a growing consumer involvement in the shaping of food systems. In debates on AFNs contributions from Spain have been relatively scarce, not because these tendencies do not occur but rather because applied analytical frameworks somehow did not seem to capture the specific nature of experiences in the peninsula. Against this background, this paper aims to analyze emerging grassroots food movements in Spain, explore to what extent different initiatives constitute a coherent alternative paradigm for sustainable local food systems, and identify relevant dimensions that shape their development and potential contribution to the sustainable development of rural areas and society at large. The paper is mainly based on case studies from Andalucia and the Basque country, and stresses that food initiatives have been largely driven by social movements, incl. peasant‐based farmers and consumer groups but also agroecology movements. As a result, Spanish food movements often have a wider focus and combine ethical values like fairness, solidarity and participative democracy with economic and environmental concerns

Clinical workplace-learning today:how competency frameworks inform clinical workplace learning (and how they do not)

The medical profession is changing due to increasing expectations, technological advancements, changing demographics and awareness of the unsustainable healthcare expenditure. In order to better prepare doctors for their future jobs, medical curricula adopt competency-based approaches that define ultimate learning outcomes. This thesis reveals that the promise of competency-based medical education is not readily achieved. Medical training largely takes place at the clinical workplace, that tends to be unruly and reluctant to change. For instance, we found a dominant focus on time-efficiency, that seemed to hamper patient-centeredness. We formulate important pitfalls that need to be addressed, and showcase that a curriculum change in clinical workplace learning might actually require organisational change