10,291 research outputs found

    Performance Analysis of Traffic and Mobility Models on Mobile and Vehicular Ad Hoc Wireless Networks

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    Advances in wireless communication technology and the proliferation of mobile devices enable the capa- bilities of communicating with each other even in areas with no pre-existing communication infrastructure. Traffic and mobility models play an important role in evaluating the performance of these communication networks. Despite criticism and assumption from various researches on Transmission Control Protocols (TCP), weaknesses on Mobile Ad Hoc Network (MANET), and Vehicular Ad Hoc Network (VANET). A simulation was carried out to evaluate the performance of Constant Bit Rate, Variable Bit Rate and Transmission Control Protocol on MANET and VANET using DSR routing protocol. CBR, VBR, and TCP have different manufacturer operation mechanisms and these differences lead to significant performance of CBR and VBR over TCP with better throughput and less average maximal end-to-end delay. DSR was able to respond to link failure at low mobility which led to TCP’s performance in packets delivery

    On the Covariant Quantization of the 2nd-Ilk Superparticle

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    This paper is devoted to the quantization of the second-ilk superparticle using the Batalin-Vilkovisky method. We show the full structure of the master action. By imposing gauge conditions on the gauge fields rather than on coordinates we find a gauge-fixed quantum action which is free. The structure of the BRST charge is exhibited and the BRST cohomology yields the same physical spectrum as the light- cone quantization of the usual superparticle.Comment: 17 page

    Ensuring Food Security - A Case for ASEAN Integration

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    The ASEAN member countries can be grouped into three sub-groups, each of which exhibits a distinct pattern with respect to food security issues. The first group is made up of the relatively food-secure countries of Singapore and Brunei. The second group consists of Malaysia, Thailand, Philippines, Indonesia, and Vietnam. In these countries, except for Vietnam, agriculture has contributed a declining share in GDP, employment, and international trade. In addition, food habits in these countries have changed dramatically in recent decades. The third group is composed of Cambodia, Lao PDR, and Myanmar - economies in transition that require special attention. A simple exercise shows that the area can collectively achieve food security via trade in rice and maize. Trade facilitation measures and the harmonization/equivalency of food regulation and control standards will reduce the cost of trade in food products. While specialization and revealed comparative and competitive indices point to complementarities between trade patterns among the ASEAN member countries, intra-ASEAN trade in agriculture is quite small. However, integration could address this problem. Further, if integration is to be used as a venue for ensuring food security, the member countries must agree on what food security collectively means to them, and what food items are important to each of them and the region, in general, so that regional integration and cooperation under the auspices of ASEAN can be promoted.food security, ASEAN, integration

    Cellular system information capacity change at higher frequencies due to propagation loss and system parameters

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    In this paper, mathematical analysis supported by computer simulation is used to study cellular system information capacity change due to propagation loss and system parameters (such as path loss exponent, shadowing and antenna height) at microwave carrier frequencies greater than 2 GHz and smaller cell size radius. An improved co-channel interference model, which includes the second tier co-channel interfering cells is used for the analysis. The system performance is measured in terms of the uplink information capacity of a time-division multiple access (TDMA) based cellular wireless system. The analysis and simulation results show that the second tier co-channel interfering cells become active at higher microwave carrier frequencies and smaller cell size radius. The results show that for both distance-dependent: path loss, shadowing and effective road height the uplink information capacity of the cellular wireless system decreases as carrier frequency increases and cell size radius R decreases. For example at a carrier frequency fc = 15.75 GHz, basic path loss exponent α = 2 and cell size radius R = 100, 500 and 1000m the decrease in information capacity was 20, 5.29 and 2.68%
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