160 research outputs found

    Crossing the frontier to survive: mainstream churches and the 'Pentecost' in Buea-Cameroon, 1960-2020

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    This study deals with the borrowing of Pentecostal practices by mainstream churches in the town of Buea in Cameroon. Contrary to the impression given by the conceptualizers of 'Pentecost' who consider it as a de-territorialized place or a space characterized by the only presence of Pentecostals and their culture, this reflection which relies on diffusion theory, postulates that ‘Pentecost’ is not solely a matter of Pentecostals. It is a heterogeneous sphere shared by mainstream and Pentecostal churches. This sharing has led to the borrowing of Pentecostal religious forms by the former notably through proximity and media used to diffuse Pentecostal culture. By focusing on Buea which religious setting is a mosaic of Christian Churches with more than one hundred Pentecostal groups and about only six mainstream churches, the paper states that the latter are progressively becoming part of 'Pentecost' by adopting Pentecostal style. Pentecostal forms are usually expressed in mainstream churches activities principally through the way of preaching and praying. In some cases Pentecostal songs are even performed by church members. In the Catholic Church precisely, these forms are highly noticed in charismatic renewal groups where healings, glossolalia and crusades which are key features of 'Pentecost' are also practiced. The work relies on qualitative data collected in Buea through interviews, participant observation and media

    Improving Roadside Unit deployment in vehicular networks by exploiting genetic algorithms

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    Vehicular networks make use of the Roadside Units (RSUs) to enhance the communication capabilities of the vehicles in order to forward control messages and/or to provide Internet access to vehicles, drivers and passengers. Unfortunately, within vehicular networks, the wireless signal propagation is mostly affected by buildings and other obstacles (e.g., urban fixtures), in particular when considering the IEEE 802.11p standard. Therefore, a crowded RSU deployment may be required to ensure vehicular communications within urban environments. Furthermore, some applications, notably those applications related to safety, require a fast and reliable warning data transmission to the emergency services and traffic authorities. However, communication is not always possible in vehicular environments due to the lack of connectivity even employing multiple hops. To overcome the signal propagation problem and delayed warning notification time issues, an effective, smart, cost-effective and all-purpose RSU deployment policy should be put into place. In this paper, we propose the genetic algorithm for roadside unit deployment (GARSUD) system, which uses a genetic algorithm that is capable of automatically providing an RSU deployment suitable for any given road map layout. Our simulation results show that GARSUD is able to reduce the warning notification time (the time required to inform emergency authorities in traffic danger situations) and to improve vehicular communication capabilities within different density scenarios and complexity layouts

    Les Pionniers Locaux de l'animation Radio au Nord-Cameroun: Entre Subalternité et Mobilité Sociale (1958-début des années 2000)

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    This article deals with the place and status of radio local pioneers in the making and the evolution of Northern Cameroon's media landscape and social space. Drawing from history from below, it uses bourdieusian sociology and subaltern studies theories as entries to question the emergence and the social (re)positioning of the first radio local actors in Northern Cameroon's social space. As radio hosts assigned to the production of programs in local languages, these pioneers were second class professional who emerged in the framework of mutations induced by colonization. Thanks to their recruitment in Radio-Garoua - the first radio implanted in the region in 1958 - they constituted a new socio-professional category/class, in a society apportioned between tradition and modernity. Through empirical data provided by three biographies (Ahmadou Abdou, Adam Alhadji and Haoua Siddiki), the study reveals that the trajectories of these pioneers were determined by the French (neo) colonial policies and the perpetuation of Muslim hegemony under Ahmadou Ahidjo's regime (1960-1982). This sociopolitical context contributed in making their social status ambivalent. Benefiting from the cultural capital conferred on them by their belonging to the Muslim community, they integrated the modern society where they were looked upon as subalterns whereas this integration valued their image and status in the traditional society

    Économie politique de la presse écrite au Nord-Cameroun postcolonial

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    This paper seeks to address the political participation of the press in the Northern Cameroon after the beginning of the democratic process which led to the institutionalization of freedom of speech in 1990. Through a Political Economy of Communication perspective, it aims at focusing on L'Harmattan and L'OEil du Sahel -which are the main newspapers in Northern Cameroon- to question the political capital of the press in this area where there is an hegemonic competition between ethno-tribal communities. The paper provides a venue to unveil the contribution of L'Harmattan and L'OEil du Sahel to rivalries between elites in sight of their positioning on the political chessboard at local and national levels. It arises from the analysis of the publications of those newspapers that they have a partisan position in the political opposition between the Fulbe who are Muslims and the Kirdi who are non-Muslims. L'Harmattan supports the first while L'OEil du Sahel has affinities with the others

    On the Study of Vehicle Density in Intelligent Transportation Systems

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    Vehicular ad hoc networks (VANETs) are wireless communication networks which support cooperative driving among vehicles on the road. The specific characteristics of VANETs favor the development of attractive and challenging services and applications which rely on message exchanging among vehicles. These communication capabilities depend directly on the existence of nearby vehicles able to exchange information. Therefore, higher vehicle densities favor the communication among vehicles. However, vehicular communications are also strongly affected by the topology of the map (i.e., wireless signal could be attenuated due to the distance between the sender and receiver, and obstacles usually block signal transmission). In this paper, we study the influence of the roadmap topology and the number of vehicles when accounting for the vehicular communications capabilities, especially in urban scenarios. Additionally, we consider the use of two parameters: the SJ Ratio (SJR) and the Total Distance (TD), as the topology-related factors that better correlate with communications performance. Finally, we propose the use of a new density metric based on the number of vehicles, the complexity of the roadmap, and its maximum capacity. Hence, researchers will be able to accurately characterize the different urban scenarios and better validate their proposals related to cooperative Intelligent Transportation Systems based on vehicular communications

    Reducing emergence services arrival time by using vehicular communications and Evolution Strategies

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    Nowadays, traffic jams in urban areas have become a problem that keeps growing every year since the number of vehicles in our cities is continuously increasing. One of the most common causes producing traffic jams are vehicle accidents. Moreover, the arrival time of the emergency services could be raised due to traffic congestion. Intelligent Transportation Systems (ITS) have a key role in order to reduce or mitigate this problem. In this paper, we propose four different approaches addressing the traffic congestion problem, comparing them to obtain the best solution. Using V2I communications, we are able to accurately estimate the traffic density in a certain area, which represents a key parameter to perform efficient traffic redirection, thereby reducing the emergency services arrival time, and avoiding traffic jams when an accident occurs. Specifically, we propose two approaches based on the Dijkstra algorithm, and two approaches based on Evolution Strategies. Notice that, when an accident occurs, time is a critical issue, and the strategies here proposed contribute to find the optimal solution within a short time period.This work was partially supported by the Ministerio de Ciencia e Innovacion, Spain, under Grant TIN2011-27543-C03-01, as well as by the Fundacion Universitaria Antonio Gargallo, the Obra Social de Ibercaja, under Grant 2013/B010, and by the Government of Aragon and the European Social Fund (T91 Research Group).Barrachina, J.; Garrido, P.; Fogue, M.; Martínez, FJ.; Cano Escribá, JC.; Tavares De Araujo Cesariny Calafate, CM.; Manzoni, P. (2014). Reducing emergence services arrival time by using vehicular communications and Evolution Strategies. Expert Systems with Applications. 41(4):1206-1217. https://doi.org/10.1016/j.eswa.2013.08.004S1206121741

    Using topology and neighbor information to overcome adverse vehicle density conditions

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    Vehicular networks supporting cooperative driving on the road have attracted much attention due to the plethora of new possibilities they offer to modern Intelligent Transportation Systems. However, research works regarding vehicular networks usually obviate assessing their proposals in scenarios including adverse vehicle densities, i.e., density values that significantly differ from the average values, despite such densities can be quite common in real urban environments (e.g. traffic jams). In this paper, we study the effect of these hostile conditions on the performance of different schemes providing warning message dissemination. The goal of these schemes is to maximize message delivery effectiveness, something difficult to achieve in adverse density scenarios. In addition, we propose the Neighbor Store and Forward (NSF) scheme, designed to be used under low density conditions, and the Nearest Junction Located (NJL) scheme, specially developed for high density conditions. Simulation results demonstrate that our proposals are able to outperform existing warning message dissemination schemes in urban environments under adverse vehicle density conditions. In particular, NSF reduces the warning notification time in low vehicle density scenarios, while increasing up to 23.3% the percentage of informed vehicles. As for high vehicle density conditions, NJL is able to inform the same percentage of vehicles than other existing approaches, while reducing the number of messages up to 46.73%This work was partially supported by the Ministerio de Ciencia e Innovacion, Spain, under Grant TIN2011-27543-C03-01, by the Fundacion Universitaria Antonio Gargallo and the Obra Social de Ibercaja, under Grant 2013/B010, as well as the Government of Aragon and the European Social Fund (T91 Research Group).Sanguesa, JA.; Fogue, M.; Garrido, P.; Martinez, FJ.; Cano Escribá, JC.; Tavares De Araujo Cesariny Calafate, CM. (2014). Using topology and neighbor information to overcome adverse vehicle density conditions. Transportation Research Part C: Emerging Technologies. 42:1-13. https://doi.org/10.1016/j.trc.2014.02.010S1134

    An Infrastructureless Approach to Estimate Vehicular Density in Urban Environments

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    In Vehicular Networks, communication success usually depends on the density of vehicles, since a higher density allows having shorter and more reliable wireless links. Thus, knowing the density of vehicles in a vehicular communications environment is important, as better opportunities for wireless communication can show up. However, vehicle density is highly variable in time and space. This paper deals with the importance of predicting the density of vehicles in vehicular environments to take decisions for enhancing the dissemination of warning messages between vehicles. We propose a novel mechanism to estimate the vehicular density in urban environments. Our mechanism uses as input parameters the number of beacons received per vehicle, and the topological characteristics of the environment where the vehicles are located. Simulation results indicate that, unlike previous proposals solely based on the number of beacons received, our approach is able to accurately estimate the vehicular density, and therefore it could support more efficient dissemination protocols for vehicular environments, as well as improve previously proposed schemes.This work was partially supported by the Ministerio de Ciencia e Innovacion, Spain, under Grant TIN2011-27543-C03-01, as well as by the Fundacion Universitaria Antonio Gargallo (FUAG), and the Caja de Ahorros de la Inmaculada (CAI).Sanguesa, JA.; Fogue, M.; Garrido, P.; Martinez, FJ.; Cano Escribá, JC.; Tavares De Araujo Cesariny Calafate, CM.; Manzoni, P. (2013). An Infrastructureless Approach to Estimate Vehicular Density in Urban Environments. Sensors. 13(2):2399-2418. doi:10.3390/s130202399S2399241813

    Understanding Evolutionary Algorithms through Interactive Graphical Applications

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    It is very common to observe, especially in Computer Science studies that students have difficulties to correctly understand how some mechanisms based on Artificial Intelligence work. In addition, the scope and limitations of most of these mechanisms are usually presented by professors only in a theoretical way, which does not help students to understand them adequately. In this work, we focus on the problems found when teaching Evolutionary Algorithms (EAs), which imitate the principles of natural evolution, as a method to solve parameter optimization problems. Although this kind of algorithms can be very powerful to solve relatively complex problems, students often have difficulties to understand how they work, and how to apply them to solve problems in real cases. In this paper, we present two interactive graphical applications which have been specially designed with the aim of making Evolutionary Algorithms easy to be understood by students. Specifically, we present: (i) TSPS, an application able to solve the ”Traveling Salesman Problem”, and (ii) FotEvol, an application able to reconstruct a given image by using Evolution Strategies. The main objective is that students learn how these techniques can be implemented, and the great possibilities they offer

    Non-emergency patient transport services planning through genetic algorithms

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    Non-emergency Patient Transport Services (PTS) are provided by ambulance companies for patients who do not require urgent and emergency transport. These patients require transport to or from a health facility like a hospital, but due to clinical requirements are unable to use private or public transport. This task is performed nowadays mainly by human operators, spending a high amount of time and resources to obtain solutions that are suboptimal in most cases. To overcome this limitation, in this paper we present NURA (Non-Urgent transport Routing Algorithm), a novel algorithm aimed at ambulance route planning. In particular, NURA relies on a genetic algorithm to explore the solution space, and it includes a scheduling algorithm to generate detailed routes for ambulances. Experimental results show that NURA is able to outperform human experts in several real scenarios, reducing the time spent by patients in ambulances during non-emergency transportations, increasing ambulance usage, while saving time and money for ambulance companies
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