11,223 research outputs found

    Evaluating the effects of road hump on speed and noise level at a university setting

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    This study is carried out to determine the effectivness of road humps to reduce the traffic speed and traffic noise in institutional area. The difference in hump profiles in terms of height, width and length are the main factors in determing the effectiveness of road humps. The difference in the profiles of the road hump will cause changing driver behaviour of the users especially when approaching the road hump. The road humps with different design profiles are selected to measure the speed and noise level of the vehicles at, before and after each of the selected road humps. Radar speed gun and noise level meters are used to measure speed and noise level of the vehicles at each of designated points along the major circular road in IIUM. The changes in speed and noise level at different selected points at each of the different profiles of the road humps are the expected findings of this study

    Evaluating the effects of road hump on the speed of vehicles in an institutional environment

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    Vehicles travelling at speed above the permissible speed limit have jeopardized the safety of road users. The concern is greater at institutional environment whereby most road users travel by walking. Road hump is considered as an efficient traffic calming measure in reducing the speed of the vehicle. This paper investigates the effects of different road hump dimensions in decreasing the speed of vehicles at the main road of International Islamic University Malaysia. Six (6) road humps with different design profile were selected. The design profile and spot speed of the vehicles at all six (6) road humps were measured. The speed of vehicles at the road hump was analyzed by using descriptive analysis and t-test. The findings of this study suggest that road hump is effective in lowering the speed of vehicles in an institutional environment. The dimensions of road hump, especially height, influence significantly the speed reduction of vehicles

    Prospects of electric vehicles in the developing countries : a literature review

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    Electric mobility offers a low cost of travel along with energy and harmful emissions savings. Nevertheless, a comprehensive literature review is missing for the prospects of electric vehicles in developing countries. Such an overview would be instrumental for policymakers to understand the barriers and opportunities related to different types of electric vehicles (EVs). Considering the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines, a systematic review was performed of the electronic databases Google Scholar and Web of Science for the years 2010–2020. The electric four-wheelers, hybrid electric vehicles and electric two-wheeler constituted the electric vehicles searched in the databases. Initially, 35 studies identified in the Web of Science that matched the criteria were studied. Later, 105 other relevant reports and articles related to barriers and opportunities were found by using Google Scholar and studied. Results reveal that electric four-wheelers are not a feasible option in developing countries due to their high purchase price. On the contrary, electric two-wheelers may be beneficial as they come with a lower purchase price

    Speed profile optimization of an electrified train in Cat Linh-Ha Dong metro line based on pontryagin's maximum principle

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    An urban railway is a complex technical system that consumes large amounts of energy, but this means of transportation still has been obtained more and more popularity in densely populated cities because of its features of high-capacity transportation capability, high speed, security, punctuality, lower emission, reduction of traffic congestion. The improved energy consumption and environment are two of the main objectives for future transportation. Electrified trains can meet these objectives by the recuperation and reuse of regenerative braking energy and by the energy - efficient operation. Two methods are to enhance energy efficiency: one is to improve technology (e.g., using energy storage system, reversible or active substations to recuperate regenerative braking energy, replacing traction electric motors  by energy-efficient traction system as permanent magnet electrical motors; train's mass reduction by lightweight material mass...); the other is to improve operational procedures (e.g. energy efficient driving including: eco-driving; speed profile optimization; Driving Advice System (DAS); Automatic Train Operation (ATO); traffic management optimization...). Among a lot of above solutions for saving energy, which one is suitable for current conditions of metro lines in Vietnam. The paper proposes the optimization method based on Pontryagin's Maximum Principle (PMP) to find the optimal speed profile for electrified train of Cat Linh-Ha Dong metro line, Vietnam in an effort to minimize the train operation energy consumption

    First workshop of the Asian Network for Environment and Energy: Event report

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    Asia is one of the most densely populated areas in the world. Many Asian countries experienced strong economic growth and rapid urbanization in the last decade. However, Asia is also faced with the challenge of environmental protection, energy security and CO2 emissions. The purpose of establishment of the Asian Network for Environment and Energy (ANEE) is to connect the re-search and training institutions, facilitate the exchange of experience and know-how, and initiating joint projects on environmental protection and renewable energy. The network organizes annual scientific conferences, develops projects addressing environmental problems of the region, and builds personnel training programs for renewable energy and environment. The first ANEE workshop held in Ho Chi Minh City is the launching event the network addressing air pollution, water management, solid waste and energy.Châu Á là một trong những khu vực đông dân nhất trên thế giới. Nhiều quốc gia tại châu Á đã có sự phát triển kinh tế mạnh mẽ và đô thị hóa rất nhanh trong thập kỷ vừa qua. Tuy nhiên, khu vực châu Á cũng đối mặt với các thách thức về bảo vệ môi trường, phát thải CO2 và an ninh năng lượng. Mục đích thành lập Mạng lưới châu Á về Môi trường và Năng lượng (ANEE) nhằm kết nối các tổ chức nghiên cứu và đào tạo, tạo điều kiện cho trao đổi kinh nghiệm và know-how, xây dựng các dự án tổng thể về bảo vệ môi trường và năng lượng tái tạo. Mạng lưới tổ chức các Hội thảo khoa học hàng năm, phát triển các dự án giải quyết các vấn đề môi trường thời sự của khu vực, xây dựng các chương trình đào tạo nhân lực ngành môi trường và năng lượng tái tạo. Hội thảo lần thứ nhất của ANEE được tổ chức tại Tp.Hồ Chí Minh là sự kiện khởi động Mạng lưới với các chuyên đề về Ô nhiễm không khí, Quản lý nguồn nước, chất thải rắn và năng lượng

    Study of Vehicle Movement for Mixed Traffic Modeling Using Social Force Model

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    Today, many models for describing vehicle movementhave been developed. Most of the available methods for modelingthe vehicle movement in traffic assume that vehicles move on lanesdisciplines. Meanwhile, in developing countries the traffic washeterogeneous, which means there are many types of vehicles. Indeveloping countries, each vehicles usually did not move based onlane disciplines, they move irregularly with unpredictable behavior.The vehicles used to move based on the empty space around themin order to make their travel time faster. Lately, research onmodeling the irregular movement of vehicle using Social ForceModel approached have been developed, especially for mixedtraffic condition in developing countries. This paper will explainabout the basic concept of Social Force Model theories and also willgive a review and comparison of existing the vehicle movementmodel using Social Force Model in mixed traffic condition. Basedupon the review and comparison, some practical issues such asadding some new parameters (driver’s psychology, crowd situationfactor, environmental, driver distraction, etc.) to improve theaccuracy and reliability of vehicle movement model will bepresented as a contribution from this paper

    Modeling and Design of Millimeter-Wave Networks for Highway Vehicular Communication

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    Connected and autonomous vehicles will play a pivotal role in future Intelligent Transportation Systems (ITSs) and smart cities, in general. High-speed and low-latency wireless communication links will allow municipalities to warn vehicles against safety hazards, as well as support cloud-driving solutions to drastically reduce traffic jams and air pollution. To achieve these goals, vehicles need to be equipped with a wide range of sensors generating and exchanging high rate data streams. Recently, millimeter wave (mmWave) techniques have been introduced as a means of fulfilling such high data rate requirements. In this paper, we model a highway communication network and characterize its fundamental link budget metrics. In particular, we specifically consider a network where vehicles are served by mmWave Base Stations (BSs) deployed alongside the road. To evaluate our highway network, we develop a new theoretical model that accounts for a typical scenario where heavy vehicles (such as buses and lorries) in slow lanes obstruct Line-of-Sight (LOS) paths of vehicles in fast lanes and, hence, act as blockages. Using tools from stochastic geometry, we derive approximations for the Signal-to-Interference-plus-Noise Ratio (SINR) outage probability, as well as the probability that a user achieves a target communication rate (rate coverage probability). Our analysis provides new design insights for mmWave highway communication networks. In considered highway scenarios, we show that reducing the horizontal beamwidth from 9090^\circ to 3030^\circ determines a minimal reduction in the SINR outage probability (namely, 41024 \cdot 10^{-2} at maximum). Also, unlike bi-dimensional mmWave cellular networks, for small BS densities (namely, one BS every 500500 m) it is still possible to achieve an SINR outage probability smaller than 0.20.2.Comment: Accepted for publication in IEEE Transactions on Vehicular Technology -- Connected Vehicles Serie

    Distributional effects of WTO agricultural reforms in rich and poor countries

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    Rich countries'agricultural trade policies are the battleground on which the future of the WTO's troubled Doha Round will be determined. Subject to widespread criticism, they nonetheless appear to be almost immune to serious reform, and one of their most common defenses is that they protect poor farmers. The authors'findings reject this claim. The analysis uses detailed data on farm incomes to show that major commodity programs are highly regressive in the United States, and that theonly serious losses under trade reform are among large, wealthy farmers in a few heavily protected subsectors. In contrast, analysis using household data from 15 developing countries indicates that reforming rich countries'agricultural trade policies would lift large numbers of developing country farm households out of poverty. In the majority of cases these gains are not outweighed by the poverty-increasing effects of higher food prices among other households. Agricultural reforms that appear feasible, even under an ambitious Doha Round, achieve only a fraction of the benefits for developing countries that full liberalization promises, but protect U.S. large farms from most of the rigors of adjustment. Finally, the analysis indicates that maximal trade-led poverty reductions occur when developing countries participate more fully in agricultural trade liberalization.Rural Poverty Reduction,Economic Theory&Research,Population Policies,Achieving Shared Growth
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