Generalized Centrifugal Force Model for Pedestrian Dynamics

A spatially continuous force-based model for simulating pedestrian dynamics is introduced which includes an elliptical volume exclusion of pedestrians. We discuss the phenomena of oscillations and overlapping which occur for certain choices of the forces. The main intention of this work is the quantitative description of pedestrian movement in several geometries. Measurements of the fundamental diagram in narrow and wide corridors are performed. The results of the proposed model show good agreement with empirical data obtained in controlled experiments.Comment: 10 pages, 14 figures, accepted for publication as a Regular Article in Physical Review E. This version contains minor change

VFR travel and second homes tourism : the missing link?: the case of South Africa

Visiting friends and relatives (VFR) travel and second homes tourism as topics of investigations have seen an upsurge in international research over the past twenty years. However, rarely has the conceptual link between the two issues been explored at any great length. The purpose of this paper is to explore the nexus between VFR travel and second homes tourism with particular reference to the Global South. The case of South Africa provides the empirical context. It is revealed that VFR travel and second homes in South Africa must be understood in terms of two circuits. The first circuit, mainly of affluent whites, mirrors the experiences of the Global North with VFR travel linked to recreational second homes. The second circuit shows the experiences of the Global South where working class residents migrate between first and second homes through circular migration as a consequence of labour migration

Modeling Decentralized Organizational Change in Honeybee Societies

Multi-agent organizations in dynamic environments, need to have the ability to adapt to environmental changes to ensure a continuation of proper functioning. Such adaptations can be made through a centralized decision process or come from the individuals within the organization. In the domain of social insects, such as honeybees and wasps, organizations are known to adapt in a decentralized fashion to environmental changes. An organizational model for decentralized organizational change is presented that can aid in analyzing and designing such organizations. The model is specified by dynamic properties at different aggregation levels. At the lowest level such properties characterize the behavior of individual roles, which can be related to higher level properties that express important elements such as survival of an organization. A honeybee colony is used as a case study

Data challenges and solutions in the calculation of Tourism Climate Index (TCI) scores in South Africa

Climatic indices are a valuable yardstick for comparing regions of differing climate regimes. This is particularly useful for economic sectors that are heavily climate-reliant. The selection of a vacation destination by tourists is strongly influenced by the climate. Climate influences the choice of destination, the timing of vacations and the success of outdoor attractions. The Tourism Climatic Index (TCI) is a widely adopted measure of the climatic suitability for tourism of a particular destination. The climatic data required for the calculation of climatic suitability using this index, however, provide limitations for its adoption in much of the African continent, for which regular measurement of the complete set of variables does not occur. South Africa is one such example, which although supporting a large network of meteorological stations, has very few recording sunshine hours. This paper therefore proposes a mathematical adaptation of the index to facilitate the calculation of TCI scores for destinations. TCI scores produced using this mathematical adaptation for stations that do have sunshine hour measurements are compared with the scores using the standard TCI equation, and demonstrate suitability of this approach. Such adaptations to the model should facilitate a more widespread use of TCI scores in the global South

An Ambient Agent Model for Monitoring and Analysing Dynamics of Complex Human Behaviour

In ambient intelligent systems, monitoring of a human could consist of more complex tasks than merely identifying whether a certain value of a sensor is above a certain threshold. Instead, such tasks may involve monitoring of complex dynamic interactions between human and environment. In order to enable such more complex types of monitoring, this paper presents a generic agent-based framework. The framework consists of support on various levels of system design, namely: (1) the top level, including the interaction between agents, (2) the agent level, providing support on the design of individual agents, and (3) the level of monitoring complex dynamic behaviour, allowing the specification of the aforementioned complex monitoring properties within the agents. The approach is exemplified by a large case study concerning the assessment of driving behaviour, and is applied to two smaller cases as well (concerning fall detection of elderly, and assistance of naval operations, respectively), which are briefly described. These case studies have illustrated that the presented framework enables developers within ambient intelligence to build systems with more expressiveness regarding their monitoring focus. Moreover, they have shown that the framework is easy to use and applicable in a wide variety of domains. © 2011 - IOS Press and the authors. All rights reserved

Insight into American tourists experiences with weather in South Africa

Weather and climate are often important factors determining the success of a tourism destination and resultant satisfaction among tourists. This is particularly true for South Africa due the predominance of outdoor tourist attractions. Increasing numbers of international tourists have visited South Africa since the fall of apartheid, particularly those from the United States (U.S.), which is an important market for South African tourism. Therefore, this paper seeks to examine a sample of American tourists experience with day-to-day weather and climatic conditions in South Africa. The results show that although respondents did not feel that climatic conditions were an important factor in motivations to visit the country, the day-to-day weather did often impact the enjoyment of their visit. Most notably, weather controlled their ability to participate in outdoor activities. In correlating accounts of unpleasant weather conditions with the meteorological records, a close association emerged, particularly for excessively high temperatures. This indicates that the experiences of American tourists are an accurate indication of climatic unsuitability for tourism, which poses threats to the South African outdoor tourism sector.