Addis Ababa, Ethiopia
Addis Ababa, Ethiopia

Addis Ababa University is a state university in Addis Ababa, the capital of Ethiopia. Originally called the University College of Addis Ababa at its establishment in 1950, it was later renamed Haile Selassie I University in 1962 after the Ethiopian Emperor Haile Selassie I. The institution received its current name in 1975. Wikipedia.


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Aschalew Y.,Bahir Dar University | Mamo M.,Addis Ababa University
IEEE AFRICON Conference | Year: 2015

In concentrated winding multi-phase permanent magnet machines, harmonic currents are intentionally injected to produce additional torque. However, harmonics result additional power losses, core temperature rise and reduction in efficiency. In this paper, analysis on the electrical power losses due to the harmonics in nine-phase permanent magnet synchronous motor is done. Analytical loss model and modified nine-phase machine, accounting for the power losses are derived. The analytical model is to generate the flux distribution in different regions of the machine and determine the losses as the result of the non-sinusoidal flux distribution. The modified model for nine-phase machine is presented to show an appropriate operating points which minimizes the total electrical loss (copper plus core loss). Comparison of power loss and efficiency in nine-phase machine with that of equivalent three phase machines is also explored. © 2015 IEEE.


News Article | December 22, 2016
Site: www.24-7pressrelease.com

DUMFRIES, ENGLAND, December 22, 2016-- Dr. Jacob S. Dreyer has been included in Marquis Who's Who. As in all Marquis Who's Who biographical volumes, individuals profiled are selected on the basis of current reference value. Factors such as position, noteworthy accomplishments, visibility, and prominence in a field are all taken into account during the selection process.An esteemed surgeon and consultant born in Cape Town, South Africa, Dr. Dreyer received a Bachelor of Medicine and Bachelor of Surgery from Stellenbosch University before obtaining a Master of Medicine in surgery from the same school. He then earned a Fellowship of the College of Surgeons of South Africa (FCS) in surgery through the Colleges of Medicine of South Africa. After relocating to the United Kingdom, Dr. Dreyer attained a Master of Education in surgical education from Imperial College London.Dr. Dreyer has utilized his strong educational foundation in a number of roles throughout his career. Since 1999, he has served as a consultant and general surgeon for NHS Dumfries & Galloway, specializing in the areas of colorectal disease, critical care, and global surgery. Dr. Dreyer is also noted for his position as chair of the Education and Research Committee for the International Federation of Surgical Colleges. He served as editor for the book, "Critical Care Handbook for Global Surgery," and has contributed a number of articles to professional publications.Additionally, Dr. Dreyer has held several teaching and training roles in critical care education and global surgery. These include being a member of the University of Edinburgh's Global Health Academy, an honorary visiting professor of surgery at Addis Ababa University, and a trainer of surgeons in Ethiopia, Zambia, Kenya, Rwanda and Tanzania through COSECSA. Further positions include convener of critical care courses for the Royal College of Surgeons of Edinburgh, board member of NHS Scotland's Diagnostics Collaborative, and review panel member of NHS Scotland's Surgical Profiles.Dr. Dreyer's professional affiliations include fellowships of the Royal College of Surgeons of Edinburgh and College of Surgeons of East, Central and Southern Africa (COSECSA), memberships of the Association of Surgeons of Great Britain and Ireland, and the Global Initiative for Emergency and Essential Surgical Care of the World Health Organization. His varied accomplishments were taken into consideration when he was chosen to be featured in the 28th through 33rd edition of Who's Who in World.About Marquis Who's Who :Since 1899, when A. N. Marquis printed the First Edition of Who's Who in America , Marquis Who's Who has chronicled the lives of the most accomplished individuals and innovators from every significant field of endeavor, including politics, business, medicine, law, education, art, religion and entertainment. Today, Who's Who in America remains an essential biographical source for thousands of researchers, journalists, librarians and executive search firms around the world. Marquis now publishes many Who's Who titles, including Who's Who in America , Who's Who in the World , Who's Who in American Law , Who's Who in Medicine and Healthcare , Who's Who in Science and Engineering , and Who's Who in Asia . Marquis publications may be visited at the official Marquis Who's Who website at www.marquiswhoswho.com


Yohannes E.,Hawassa University | Hailemariam D.,Addis Ababa University
IEEE AFRICON Conference | Year: 2015

This paper presents joint adaptive modulation and multiple-input multiple-output (MIMO) system (JAMAMS) in Long Term Evolution (LTE) network that adapts both modulation type and MIMO scheme based on channel conditions. Specifically, four adaptive modulation-based MIMO techniques, namely, 1 × 2 MIMO with maximum ratio combining (MRC); 2 × 1 and 2 × 2 Alamouti techniques; and 2 × 2 Vertical Bell Labs Layered Space-Time Architecture (V-BLAST) are investigated. Bit error rate (BER) and spectral efficiency (SE) are used as performance metrics and Zero Forcing (ZF) detection is used in all the MIMO techniques. For each of the four techniques, first the signal-to-noise (SNR) thresholds for switching from one modulation order to the next (i.e., adaptive modulation) are determined. Then, based on comparison of the thresholds of the four schemes, a proposal is made when the system has to switch from one MIMO scheme to the other; and the resulting system is called JAMAMS. In the uplink scenario, as an example, adaptive modulation-based 2 × 2 Alamouti, 1 × 2 scheme with MRC, and 2 × 2 V-BLAST schemes have shown 'optimal' SE performance in the SNR ranges 4-19 dB, 19 dB-28 dB, and greater than 28 dB, respectively, while satisfying target BER constraint, BERth ≤ 10-2. Moreover, it is shown that JAMAMS has comparable computational complexity in comparison to fixed MIMO systems. © 2015 IEEE.


News Article | December 9, 2015
Site: www.gwec.net

There’s a revolution blowing along the highlands about 95 km southeast of Addis Ababa, Ethiopia’s capital. Standing high up on the Great Rift Valley, row upon row of giant white wind turbines spin freely, churning out valuable green energy to supplement the nation’s grid. They belong to the Adama Wind Farm, installed by Chinese company HydroChina International Engineering Co. Ltd. Adama Wind Farm boasted an installed capacity of 50 MW in the first phase. The second phase of the project completed this May, and with an installed capacity of 153 MW, it has become the largest wind farm in Sub-Saharan Africa. Abebayehu Assefa, the project’s consultant engineer, is proud to have witnessed Adama’s progress from blueprint to reality. The professor at the Institute of Technology of Addis Ababa University says the Ethiopian side developed an in-depth understanding of China’s wind power technology and equipment development, as well as management experience, by working with Chinese engineers. “We are happy that Ethiopians had, for the first time, participated in an international consultancy at the Adama wind power project,” Assefa said. “We would like to enjoy long-term cooperation with Chinese wind turbine companies in the future, which would mean a lot to our domestic clean energy development.” Upon completion, the project will meet 20 percent of the power demand in the Ethiopian capital and ease the prevailing power shortage considerably


Medhn S.,Adigrat University | Hailemariam D.,Addis Ababa University
IEEE AFRICON Conference | Year: 2015

In this paper, we propose a cooperative Multiple-Input Multiple Output (MIMO) system where the cooperation uses amplify-and-forward (AF) relaying strategy and the MIMO is based on Vertical Bell-Labs Layered Space Time (V-BLAST) architecture. The idea is to simultaneously exploit the advantages offered by cooperative diversity and MIMO and the proposed system is intended for use in Worldwide Interoperability for Microwave Access (WiMAX) technology. Complexity of the cooperative MIMO (Co-MIMO) is also analyzed considering Maximum Ratio Combining (MRC) and Equal Gain Combining (EGC) schemes; Zero Forcing (ZF), Minimum Mean Square error (MMSE) and Maximum Likelihood (ML) detections; and V-BLAST transmission technique at transmitting node. Simulation results show that, at comparable complexity, Co-MIMO achieves significantly better symbol error rate (SER) performance than the conventional cooperative diversity or MIMO system only. As an example, at SER of 10-3, Co-MIMO system using MMSE detection has 10 dB signal-to-noise ratio (SNR) gain over systems that employ cooperative diversity or MIMO only. © 2015 IEEE.


Mekonnen S.K.,Addis Ababa University | Mekonnen S.K.,Armauer Hansen Research Institute | Mekonnen S.K.,University of Tübingen | Aseffa A.,Armauer Hansen Research Institute | And 3 more authors.
Malaria Journal | Year: 2014

Background: With 75% of the Ethiopian population at risk of malaria, accurate diagnosis is crucial for malaria treatment in endemic areas where Plasmodium falciparum and Plasmodium vivax co-exist. The present study evaluated the performance of regular microscopy in accurate identification of Plasmodium spp. in febrile patients visiting health facilities in southern Ethiopia. Methods. A cross-sectional study design was employed to recruit study subjects who were microscopically positive for malaria parasites and attending health facilities in southern Ethiopia between August and December 2011. Of the 1,416 febrile patients attending primary health facilities, 314 febrile patients, whose slides were positive for P. falciparum, P. vivax or mixed infections using microscopy, were re-evaluated for their infection status by PCR. Finger-prick blood samples were used for parasite genomic DNA extraction. Phylogenetic analyses were performed to reconstruct the distribution of different Plasmodium spp. across the three geographical areas. Results: Of the 314 patients with a positive thick blood smear, seven patients (2%) were negative for any of the Plasmodium spp. by nested PCR. Among 180 microscopically diagnosed P. falciparum cases, 111 (61.7%) were confirmed by PCR, 44 (24.4%) were confirmed as P. vivax, 18 (10%) had mixed infections with P. falciparum and P. vivax and two (1.1%) were mixed infections with P. falciparum and P. malariae and five (2.8%) were negative for any of the Plasmodium spp. Of 131 microscopically diagnosed P. vivax cases, 110 (84%) were confirmed as P. vivax, 14 (10.7%) were confirmed as P. falciparum, two (1.5%) were P. malariae, three (2.3%) with mixed infections with P. falciparum and P. vivax and two (1.5%) were negative for any of the Plasmodium spp. Plasmodium falciparum and P. vivax mixed infections were observed. Plasmodium malariae was detected as mono and mixed infections in four individuals. Conclusion: False positivity, under-reporting of mixed infections and a significant number of species mismatch needs attention and should be improved for appropriate diagnosis. The detection of substantial number of false positive results by molecular methodologies may provide the accurate incidence of circulating Plasmodium species in the geographical region and has important repercussions in understanding malaria epidemiology and subsequent control. © 2014 Mekonnen et al.; licensee BioMed Central Ltd.


Assefa T.,Development Bank of Ethiopia | Wencheko E.,Addis Ababa University
Ethiopian Journal of Health Development | Year: 2012

Background: Health care planning depends upon good knowledge of prevalence that requires a clear understanding of survival patterns of patients who receive medication, treatment and care. Survival analysis can bring to light the effect that some demographic, social, medical and clinical characteristics have on the mortality rate of HIV-patients. Objectives: The objective of this research undertaking was to estimate mortality rate and identify predictors that have significant impact on the survival status of a sample of patients who received antiretroviral treatment and care in Tikur Anbessa Specialized Hospital, Addis Ababa, Ethiopia. Methods: The data for this research were collected during the follow-up time from 2005 to 2008. Out of a population of HIV-patients who were taking antiretroviral therapy in the hospital in that period, data on 1,000 patients were used for this study. The study subjects were people in the age range from 15 to 75 years. The Kaplan-Meier Method was employed to estimate mortality; the Cox Proportional Hazards Regression Method was used to identify determinants of mortality. Results: After initiation of the antiretroviral treatment, HIV-positive patients lived for an average of 5.65 years (CI: 3.69-7.61 years); the median survival age was found to be 3.98 years (CI: 2.98-4.97 years). The number of medications, baseline functional status, CD4 count, antiretroviral treatment, age, gender and weight impact the survival experience of the patients. Conclusions: Antiretroviral therapy treatment reduced death among AIDS patients by 50 percent. Providing treatment at health facilities outside big towns and in the country should be given due attention. Similar studies in the future need to consider predictors in addition to those considered in this study.


Fikre Z.,Addis Ababa University | Mostefaoui A.,CNRS Femto ST Institute
2012 International Conference on Selected Topics in Mobile and Wireless Networking, ICOST 2012 | Year: 2012

Mobile peer to peer multimedia streaming is getting a lot attention, especially in instantaneous mobile networks in which users want to share their multimedia content as live streams from source peer to destination peers. The general public infatuation towards these systems is due to numerous advantages of the streaming mode: latency reduction, constant storage requirement at the receiver side, particularly suitable for low storage devises, copyright preservation, etc. Because of the temporal dimension of multimedia streams, such systems suffer however from the data unavailability problem i.e., streams that are currently viewed will not be consumed until the end because of the unpredictable source peer departure. One way to handle this problem is to use a cache to prefetch parts of the currently viewed stream so to ensure their availability. Nevertheless, when to start caching? What size of stream file need to be cached? remain open research issues that need to be addressed for maximum user satisfaction with limited cache size. This paper addresses these issues by proposing and using probabilistic users' profile in the network to decide whether there is a need for pre-caching or not. It estimates the waiting time of senders and receivers as well as viewing duration of stream file for decision making. It demonstrates that the introduced preconditions have saved a considerable amount of caching resources. © 2012 IEEE.


Adane W.,Jimma University | Hailemariam D.,Addis Ababa University
IEEE AFRICON Conference | Year: 2015

This paper investigates orthogonal frequency division multiplexing (OFDM) based cooperative communication system for frequency flat and selective channel conditions. Carrier frequency offset (CFO) that creates inter-carrier interference (ICI) is one known problem in OFDM-based systems. The CFO problem becomes worse when OFDM is integrated into the cooperative systems as identical OFDM signal suffers from several offsets at different uncorrelated channels. To minimize the multiple CFO effects, a two step technique is proposed in this work. Firstly, a time-domain windowing is used at the transmitter to reduce the effect of frequency offset due to Doppler shift. Secondly, Maximum Likelihood (ML)-based CFO estimation is used in each of the receiving nodes to reduces the effect of synchronization errors. The performance of the time-domain windowing and the ML-based CFO estimation is investigated, separately and jointly. Then, comparison of these systems with inter-carrier interference (ICI) self-cancellation and data conjugate techniques is performed. The combined technique has a signal to noise ratio (SNR) advantage of 7dB for a sample standard bit error rate (BER) value of 10-3. © 2015 IEEE.


Kebede N.,Addis Ababa University
Eastern Mediterranean health journal = La revue de santé de la Méditerranée orientale = al-Majallah al-ihhīyah li-sharq al-mutawassi | Year: 2010

To determine the prevalence of human hydatidosis in Bahir Dar and the sex and age distribution and awareness, we used a questionnaire and retrospective analysis covering 5 years of the case reports at public health institutions in Bahir Dartown and the surrounding areas. We interviewed 244 individuals: 150 households, 32 abattoir workers, 30 butchers and 32 health professionals. None of the householders or butchers knew about cystic echinococcosis, nor did 25% of the health professionals; however, 100% of the abattoir workers and 75% of the health professionals recognized it. The householders owned on average 3 livestock and 1 dog and during holidays, ceremonies and other feasts, the community mostly practised backyard slaughter. Case book analysis between January 2002 and December 2006 showed that out of the total of 36,402 patients admitted for ultrasound examination, 24 hydatidosis cases were registered, giving a mean annual incidence rate of approximately 2.3 cases per 100,000 per year. Ultrasound was the most frequently used diagnostic method.

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