Browsing by Author "Getachew, Dereje"
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Item The National Army's Participation In Primary Education A Case Study In Tita Military Camp(Addis Ababauniversity, 2006-06) Getachew, Dereje; Devi, Usha (PhD)The main purpose of this research paper is to examine the current participation of the national army in Primary education, and thereby identify the major constraints that hinder their participation to indicate possible intervention strategies for educational planners and policy makers to alleviate the educational marginalization of some members of the army who have been settled in remote areas of the nation and in restricted camps. To this end, a case study method was employed in an old Military camp, Tita, in the NorthEastern part of the nation. Apart from consultation of documents from relevant sources, data were gathered through participative observation with 3 army students, focus group discussion with 5 army teachers and interview with the school coordinator. Applying purposive sampling techniques helped me to draw these respondents. The data obtained from these sources and respondents were interpreted qualitatively, and the researcher constructs his own subjective narration based on the data collected for two months through participative observation. The data from documentary analysis indicated that the participation of members of the army in the primary school in Tita is very low. Only less than half percent of the students enrolled at the beginning of the academic year were able to remain in school and assumed to pass to the next grade level. Military obligation for conflict resolution, attitudes of the adults toward learning academic subjects, the influence of their family, low self-concepts, health problem, school factors such as curriculum relevance, the language of instruction, lack of school facilities, problems in quality and quantity of teachers, and institutional constraints have been identified as the major problems in the education participation of the army in the primary school. On top of this, time constraints of both the teach~rs and the students, lack of interest from the side of the learners and lack of additional payment for their hard work of the teachers, lack of reading rooms and books were found to be major constraints to the educational involvement of the army in primary level. Hence, it is concluded that, in most cases, participation of the army in Tita camp is afunction of material constraints, time constraints, lack of interest and negligence to learning, school intrinsic and administrative problems. Depending on the results of the findings, reforming the curriculum, budgeting time for reading and assignment, opening library, and promoting capacity building training programmes for educational personnel are recommendedItem The Role of Incretin Hormone in Type 2 Diabetes(Addis Ababa University, 2011-06) Getachew, Dereje; Dr.Seifu, DanielBackground: Type 2 diabetes mellitus is a metabolic disease associated with low quality of life and early death. It is now well established that beta-cell dysfunction and insulin resistance are two central defects in the pathophysiology of T2DM. Recently, improved understanding of the incretin effect on the pathophysiology of type 2 diabetes has led to development of new hypoglycemic agents. The incretin effect refers to the amplification of insulin secretion that occurs when glucose is ingested orally as opposed to infused intravenously in amounts that result in identical glucose excursions. Objective: To review the role of incretin hormone in type 2 diabetes. Methode: The review was conducted as a systemic review. Articles were searched from MEDLINE, HINARI and PUBMED in English language with the key words incretin or gut hormone, type 2 diabetes, and the role of incretin in type 2 diabetes. Result: A total of 65 studies were retrieved. Of these, 12 were considered to be relevant up on initial screening. Abstract of these 12 articles were reviewed and while 5 studies excluded. 7 studies were agreed upon to meet the inclusion criteria. Conclusion: The incretin effect was significantly reduced in patients with type 2 diabetes.GLP-1 concentrations and response is also reduced. But the GIP concentration is increased, reduced or normal. Incretin secretion is increased after oral glucose compared with intravenous infusion.Item Sliding Mode Control of a 2 DOF Of Freedom Robot Arm Using Permanent Magnet Synchronous Motor(2018-03) Getachew, Dereje; Mengesha, Mamo (PhD)This thesis study aims at the problem of modeling and control of a two DOF robot arm using Permanent magnet synchronous actuators. Permanent magnet synchronous actuator have been used in various industrial and domestic applications because of its advantages like simple structure, large torque, long use. Trajectory tracking is a very difficult topic in robot arm control. This is due the nonlinearities and input couplings present in the dynamics of the arm caused by dynamics changes rapidly as the manipulator moves within its working range. Moreover, for a robot with gear transmissions, the gears have nonlinearities such as hysteresis, backlash, friction, and nonlinear elasticity. In industrial applications such complex systems are controlled using the traditional PID controllers. However, a major drawback of the linear PID control is failed to track the desired trajectory of the robot arm when the nonlinear system dynamics is dominant. In this thesis sliding mode controller is modeled to overcome the shortcomings of PID controller. The SMC is designed to control the joint trajectory of the robot. SMC adopts a switching function, and these results in high-frequency oscillations (the so-called chattering) in the control signal. To reduce chattering, saturation function is used. The simulation is carried out using Level-2 MAT-LAB s-function and Simulink. PID controller is designed for the comparison purpose with SMC without disturbance and parameter variation and the result shows Steady State error of SMC is 0.029% for joints one and 0.0098% for joint two and increased to 15% and 24% respectively overshoot remain the same, rise time is decreased by 0.16sec, and settling time is decreased by 0.4sec for both joints when PID controller is used. The SMC and PID with disturbance and parameter variation also tested and results show that the performances with disturbance and parameter variation are almost the same for SMC. The control input voltage is increased by 0.03v and 0.02v for joint one and two respectively for SMC. However the amplitude of the control effort of PID controller with disturbance and parameter variation is much larger when compared to the control effort without disturbance and it is increased by 18v and 6.5v. Generally from the result it is possible to conclude that SMC has better performance, more stable and robust than PID controller.Item The Structure and Efficiency of Ethiopian Commercial bank(A.A.U, 2006-12) Getachew, Dereje; Demeke, Mulat (Dr.)Using the stochastic frontier analysis and employing the cost, standard profit, alternative profit and labor efficiency concepts, this study has analyzed the efficiency situations and identified the exogenous factors affecting the inefficiencies of the Ethiopian commercial banks from 1994/95 to 2004/05. FUl1hermore, the study has investigated whether or not management inefficiency existed in the banks and the quality difference in the outputs of the banks. The findings also depicts that Ethiopian commercial banks have on the average cost, standard profit alternative profit and labor efficiency scores of 92.2, 68, 71.3 and 80.3 percent respectively. However, the econometric findings suggest that the alternative profit efficiency concept to be the most appropriate efficiency concept to assess the Ethiopian commercial banking industry. In view of this, the study indicates that alternative profit efficiency is affected positively by the private ownership, cheap source of deposit, larger size, higher capital size, lower risk preference of the management, longer years of operation and lower number of branches even though it deteriorated over the study period. In addition, the findings also reveal the existence of management inefficiency and output quality difference among the banks. , JItem Synthetic Unit Hydrograph Derivation Using Giuh And Giuh Based Nash Iuh Models forUngauged Catchments in Abbay(Addis Ababa University, 2011-06) Getachew, Dereje; Ayalew, Semu(PhD)Geomorphologic instantaneous unit hydrograph (GIUH) can be used as a transfer function for modeling the transformation of excess rainfall into surface runoff, in which excess rainfall is a production function to the hydrologic system. These models can be used to predict the temporal variation of the surface runoff at the outlet of ungauged catchment, which is useful in the hydrologic engineering applications. In this study the two types of geomorphologic approaches were studied, GIUH and GIUH based Nash IUH models, for unit hydrograph derivation from the observed data. The geomorphological characteristics of a catchment were related with the shape and scale parameters of the Nash IUH to derive the complete shape of the GIUH based Nash IUH model; and GIUH was developed from geomorphological characteristics of the catchments and probability density function of travel time of rainfall excess to the catchment outlet. These two models were developed in seven catchments in Abay basin (Fettam, Hoha, Neshi, Uke, Andassa, Azuari and Jedebe) with range of areas 161 to 573km2. In this study, velocity was set as a calibration parameter to calibrate the simulated unit hydrograph with the observed unit hydrograph in both models. A regionalized streamflow velocity equation was developed from the simulated data with R2 equal to 0.89 and 0.96 for GIUH and GIUH based Nash IUH model respectively. Then, these equations were applied on chemoga catchment, which was considered as ungauged catchment, to observe the reliability of the models. The performances of the calibrated models were evaluated using Nash-Sutcliffe efficiency (NSE), Error (ERR), percentage error in peak discharge (PEP) and percentage error in time to peak (PETP). From model evaluation results, GIUH model efficiency (EFF) varies from 81.95 to 97.9 percent while GIUH based Nash IUH model efficiency varies from 75.68 to 97.51 percent. GIUH model is efficient in peak discharge estimation (R2=0.988) than GIUH based Nash IUH model (R2=0.884). In general, the result of both GIUH and GIUH based Nash IUH models are almost comparable and their results are acceptable but the GIUH model is superior. ii Moreover, a simple GIUH based regional triangular unit hydrograph equations were developed and compared with the SCS triangular unit hydrograph. The R2 value in peak discharge estimation using SCS method is 0.48 while using GIUH method is 0.95. This implies that the derived GIUH based regional triangular unit hydrograph equation is quite different from SCS triangular unit hydrograph and GIUH has better efficiency. Finally, this paper concludes that, the regionalized GIUH based equation for peak discharge, time to peak and base time of the triangular unit hydrograph can be used, within the errors specified in this research paper, for any ungauged catchment found in neighbor of the study area having similar character and varying in areas from 161 to 573km2. Further work may in the future be required to explain any non linear relationship of rainfall runoff and homogeneity of the catchments. KEY WORDS: Geomorphologic Instantaneous Unit Hydrograph (GIUH), Nash IUH Model, ILWIS (Integrated Land and Water Information System), Rainfall-Runoff modeling, Ungauged Catchment.