Browsing by Author "Abebe, Tesfaye"

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    Dynamics of Degenerate Three-Level Laser
    (Addis Ababa University, 2016-02) Abebe, Tesfaye; Hirpo, Deribe (PhD)
    We analyze the quantum properties of the light generated by a three-level laser coupled to a vacuum reservoir. The three-level atoms available in the cavity are pumped from the bottom to the top level at a rate rda. Employing the pertinent master equation, we obtained the equation of evolution for cavity mode and atomic operators. Moreover, we have calculated the mean and variance of the photon number, the quadrature variance and the quadrature squeezing as well as the power spectrum for the cavity mode
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    Eastern Nile River Basin Simulation with Grand Ethiopian Renaissance Dam / GERD
    (Addis Ababa University, 2015-05) Abebe, Tesfaye; Sileshi, Yilma(PhD)
    The Ethiopian government has conducted Integrated Water Resource Development Master Plan for the Blue Nile basin in 1998. The master plan has identified various irrigation and hydropower developments in the Sub basin. Since then, few projects have been implemented and some are under construction and the rest are at various levels of studies. This research is identified to evaluate and simulate the Grand Ethiopian Renaissance Dam hydropower development opportunities in the Easter Nile basin and to assess the impacts on the downstream hydropower generation and irrigation developments and other water use systems. The thesis compiled recent studies in the basin and meteorological, hydrological and demand data for each hydropower and irrigation schemes have been considered for the analysis. Mike Hydro 2014 model and Nile Basin DSS (preliminary stage) used for the study for simulation of the river water based on the existing water requirement and user priority setting situation. The model is operated by using the monthly based data in both the demand side and supply sides. The water resources availability assessment and the allocations performed by different Scenarios. The impact of the Grand Ethiopian Renaissance Dam Hydropower generation in the Eastern Nile River Basin is insignificant on the existing hydropower generation (present condition Sc-0) of the Eastern Nile River Basin. The scenario analysis result indicates that, the overall average power production during the 40 years of simulation is increased by more than 50% in the Eastern Nile River Basin. In the Roseri and Sennar, the average power production increased by 15% from the present (SC-0) condition. The Hydro power generation in the Aswan Dam is reduced by 9% from the present (SC-0) condition. Accordingly, the simulation result showed positive impact on the existing Irrigation development (present condition Sc-0) of the Eastern Nile River Basin. The impact of the Grand Ethiopian Renaissance Dam Hydropower generation in Irrigation development in the Eastern Nile River Basin is significant on the existing Irrigation development on the downstream of Eastern Nile River Basin. The scenarios result illustrates the benefit for downstream courtiers, especially, in Sudan because of increased upstream regulation in Ethiopia. An overall improved coverage of the irrigation water demand (0 month of deficit with GERD, Sc-1, against 10 months of deficit without GERD, present condition Sc-0) in the Eastern Nile Basin. The average irrigation water demand deficit during the 40 years of simulation is reduced up to zero (no deficit) in the downstream Irrigation Scheme as shown in the simulation results. In the U/S Sennar and D/S Sennar, the average irrigation water demand deficit is reduced significantly up to nil. The irrigation water demand deficit in the Gzeria and downstream of Aswan Irrigation schemes are also reduced accordingly. The results in this research are preliminary and based on many assumptions. Where it has been possible to verify the simulations the model results are reasonable. Nevertheless, the current results must be treated with caution. The model need to be refined using improved estimates of stream flow data on the major tributaries and better estimates of irrigation demand at all schemes.
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    The Practice and Challenges of Media Coverage in Reporting Tourism: In the Case of ETV News “Tena –Yistilign Ethiopia” News Package
    (Addis Ababa University, 2022-06) Abebe, Tesfaye; Mekasha (Asst. Prof.), Mekuria
    The objective of this study was to explore the practice and challenges of tourism media coverage in the ETV "Tena-Yistilign Ethiopia" news package. The research design was descriptive research design. In addition to this, a mixed research approach is employed in this study. The data collection instruments were interviews and document analysis. An interview was conducted with the editor-in-chief, shift editor, producer, news anchor/host, and reporter. Document analysis was obtained from sixty-seven tourism news broadcasts from January 1, 2019 to December 31, 2019. The findings of the study pointed out that the ETV news package has less attention to tourism reporting. The sources of information for tourism news stories are eventbased and government organizations. Some of the challenges of tourism reporting in the "Tena- Yistilign Ethiopia" news package were lack of interest and awareness of tourism reports as well as media roles, lack of infrastructure, lack of information, and time constraint. Based on the findings of the study, the following recommendations are forwarded: The management of the "Tena-Yistilign Ethiopia" news package should give due attention to tourism and assign professionals who are able to produce well-planned, organized, and quality tourism news and programs so as to promote media coverage of tourism reporting. The journalists need to be well informed about tourism and work hard to promote the sector in their news packages. The media management and other stakeholders should provide training to media and tourism professionals, tour guides, and other stakeholders to help encourage the sector's concerned bodies.