Browsing by Author "Hailu Amare"

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    Evaluation of U-turning Road Traffic crash at Median Opening In Yeka sub city, Addis Ababa
    (Addis Ababa University, 2023-06) Hailu Amare; Getu Segni (PhD0
    Road traffic crashes occur as a result of several factors associated with the traffic systems, such as road users, road environment and vehicles. Despite having low road network density and vehicle ownership, Ethiopia has a relatively high number of road traffic accident records. Consequently, Ethiopia is one of the nations across the globe with the highest fatality rate per vehicle. The research was based on the collected data from Traffic Police Office in year between 2017/18 and 2020/21. Field observations were also carried out to collect the required of primary data to be performed as complement to accident analyses. In this research Statistical analysis (multinomial logistic regression analyses) was used to decide the relationship of dependent and independent variables This study tries to analyze the traffic crashes, and develop a preventive strategies and possible counter measures for the route selected as black spot area. The aim is to provide users with an understanding of the major causes of traffic crashes and present using several Statistical tools. In Yeka sub-city the road traffic crash become serious that many people lost their lives, injured and loss of properties. U-turn at median opening traffic crash was one of the most frequently occurring collisions by different causes and area of sub city. Human error, road environment and vehicle factors are main causes of road crashes. In the study area related to driver’s errors were 91 percent, poor weather conditions 6 percent and other factors take about 3 percent. The result of the study showed that higher traffic accident cause by male drivers compared to female drivers. Also the study finds the age groups of 18-30 were mostly affected age of drivers. From the day of the week Tuesday was the highest traffic accident were recorded. And also accidents varies throughout the time of the day, hence times of the day from 7:00am-8:00am, 12:00am-1:00am, and 5:00am-6:00am were the highest accident were recorded. Improper design of cross-sectional elements like narrow Median width, narrow median opening lengths, lack of speed limit and lack sufficient sight distance on the road has been contribute own share for road traffic crashes in sub city.
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    Theoritical Range Resoulution Studies of Stradar Syatems Having Instrumental Imperfections
    (Addis Ababa University, 1992-06) Hailu Amare; Ogubazghi Ghebrebrhan (PhD)
    The range resolution of a radar system depends on a number of factors, such as the duration and shape of the transmitted radar pulse, the impulse response of the receiver matched filter, the antenna system, characteristics of some transmitting and receiving equipment, etc. In this study, the theoretical range resolution of the stratospheretroposphere CST) radar system having instrumental imperfections is considered. The imperfections considered are the width and shape of the transmitted pulse and the associated impulse response of the receiver matched filter which is assumed to be always matched to the transmitted pulse. All other parameters that influence range resolution are assumed to be ideal. A simplified model of an ST radar system suitable for resolution studies is presented and this is used to simulate atmospheric profiles