Faculty Publications

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    Prediction of daily pan evaporation using support vector machines
    (CAFET INNOVA Technical Society cafetinnova@gmail.com 1-2-18/103, Mohini Mansion, Gagan Mahal Road, Domalguda, Hyderabad 500029, 2014) Pammar, L.; Deka, P.C.
    Water scarcity globally has lead to severe problems in water management. Understanding the rate of evaporation, from surface water resources is essential for precise management of the water balance. However, evaporation is difficult to measure experimentally due to its nature. Preparing reliable forecasts of evaporation has become an essential element towards efficient water management. The objective of this paper is to predict daily pan evaporation using different kernel functions of Support Vector Machines (SVM's) based regression approach for the meteorological data obtained for the region 'Lake Abaya' which is located in the Great Rift Valley, southern part of Ethiopia. The meteorological parameters considered for study includes daily details of mean-temperature (T), wind speed (W), sunshine hours (Sh), relative humidity (Rh), rainfall (P). Among the kernel functions used for study, the polynomial kernel function proved its credibility by showing improved performance in training and testing periods. The evidence for performance of polynomial kernel function was seen in terms of correlation coefficient (CC) obtained for training and testing is respectively 0.940, 0.956 which is acceptable. © 2014 CAFET-INNOVA TECHNICAL SOCIETY.
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    Hydrological effects of land use /land cover changes on stream flow at Gilgel Abay River Basin, Upper Blue Nile, Ethiopia
    (CAFET INNOVA Technical Society 1-2-18/103, Mohini Mansion, Gagan Mahal Road, Domalguda, Hyderabad 500029, 2016) Mulu, A.; Dwarakish, G.S.
    Water is the most important resource for the survival of living things and it is the most essential resource associated with land use/ land cover (LU/LC) changes. Therefore, it is very important to make evaluations of the expected impact on the hydrology and water resources due to expected changes. The main objective of this study is to assess the hydrological effect of land use/ land cover changes on stream flow at GilgelAbay river basin using Precipitation Runoff Modeling System (PRMS) model. System inputs are daily time-series values of precipitation, minimum and maximum air temperature, and parameter files which are generated from GIS Weasel. To identify effect of changes in LU/LC, vegetation type and vegetation density on stream flow, LU/LC, vegetation type and vegetation density data from 1990-2000 and 2001-2010 years were considered. This different period LU/LC, vegetation type and vegetation density with soil data and DEM were given to GIS Weasel to generate different parameters for PRMS model. These generated parameters together with time series data (daily minimum and maximum air temperature, daily precipitation and daily stream flow) feed to PRMS model to simulate stream flow for the years 1993-2000 and 2001-2008. From the time series data, climate changes (daily maximum and minimum temperature and daily precipitations) were kept the same as baseline period (1993-2000). The stream flow of 2001-2008 compared with baseline period (1993-2000) and the effect of LU/LC, vegetation type and vegetation density was identified using calibrated and simulated PRMS model. Hence, as LU/LC, vegetation type and vegetation density changed from 1993-2000 period to 2001-2010 period, stream flow increased from 7.8% (128.4 Mm3) to 25.3% (432 Mm3) and ET decreased from 4.2% (75 Mm3) to 20% (524 Mm3) from baseline period. For the whole simulation periods (2001-2008) stream flow increased by 10.9% (784 Mm3), but ET decreased 6.7% (43 Mm3) related to baseline periods. © 2016 CAFET-INNOVA TECHNICAL SOCIETY. All rights reserved.
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    Analysis of variability and trends in rainfall over northern Ethiopia
    (Springer Verlag service@springer.de, 2016) Kiros, G.; Shetty, A.; Nandagiri, L.
    Rainfall is a key component of the hydrological cycle, and its spatiotemporal variability is essential from the both scientific and practical perspectives. This study is focused on analysis of temporal variability and trends in historical rainfall records for stations in the Geba River basin. The Geba catchment is surrounded by the Danakil basin in the east, by the Tekeze River basin in the south, and the Werie River basin in the west which is located in the northern Ethiopia regional state of Tigray between 38° 38? E and 39° 48? E and 13° 18? N and 14° 15? N. The climate over the basin is semi-arid and has large elevation differences varying from 926 to 3301 m above mean sea level. Daily rainfall data of 43 years measured at seven stations in the basin for the period of 1971 to 2013 for annual and seasonal rainfall trends have been processed and used for the analysis. The non-parametric Mann–Kendall test and the Sen’s slope estimator have been used to identify the existence of trends and slope magnitude in rainfall. Results revealed that although there was a mix of positive and negative trends, they were no statistically significant except at one station which showed an increasing trend in annual rainfall. Considering rainfall in different seasons, an increase in rainfall was observed in two stations in the wet season which, however, was not statistically significant. For the remaining stations, a weak decline in wet season rainfall (not statistically significant at 95 % confidence level) for four stations and absence of trend for one station were noticed. Furthermore, no statistically significant trend (positive or negative) was evident for the dry season rainfall. Results of this study may prove useful in the preparation of climate change mitigation and adaptation strategies in rainfed agricultural and water supply systems in the region. © 2016, Saudi Society for Geosciences.
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    Resource saving and productivity enhancing impacts of crop management innovation packages in Ethiopia
    (Blackwell Publishing Ltd customerservices@oxonblackwellpublishing.com, 2016) Jaleta, M.; Kassie, M.; Tesfaye, K.; Teklewold, T.; Jena, P.R.; Marenya, P.; Erenstein, O.
    Crop management innovations are often not discrete fixed stand-alone options—and their adoption may imply various combinations and adaptations. This potentially confounds their impact assessment. This article assesses the resource saving and productivity enhancing impacts of a crop management package revolving around minimum tillage in maize-based farming systems in northwest Ethiopia. An endogenous switching regression model was applied to plot- and household-level survey data collected from 290 rural households operating 590 maize plots during the 2012 production year. Controlling for variations in plot and household characteristics, the average effect of minimum tillage package (minimum tillage package) on maize productivity is 0.44 t/ha. Compared to conventional practice (CP), adoption of the MTP decreased the average male and female labor use in maize production by 14.4 and 8.2 person-days per ha, respectively. Similarly, MTP adoption decreased draft power use for land preparation by 13.2 pair of oxen-days per ha. Compared to CP, in general, there is a considerable short-run maize productivity gain and reduction in labor and draft power use under MTP. © 2016 International Association of Agricultural Economists
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    Construction education in Ethiopia: Knowledge and skills level attained and effectiveness of internship program
    (Emerald Group Holdings Ltd., 2019) Mengistu, D.G.; Mahesh, G.
    Purpose: The purpose of this paper is to evaluate knowledge and skills level of final-year students of undergraduate construction programs in Ethiopia and assess the effectiveness of internship and its coordination under these programs. Design/methodology/approach: A mixed-methods approach is used in this study. Data were collected through two separate questionnaires, completed by students and company supervisors (professionals having experience in supervising internship students). Interviews were held with university instructors to supplement findings of the questionnaire. Findings: The findings show the students have performance shortfalls in most of the required knowledge areas. A significant correlation was found between students’ self-evaluation and supervisors’ evaluation rankings. It was also found that both students and industry perceive the internship to have benefited them. However, the coordination of internship program was found unsatisfactory. These findings indicate there is a room for improvement in the curricula and coordination of internship program. Originality/value: As performance of the construction industry (CI) is associated with the competence of professionals, it is important to assess the knowledge and skills level of students, and internship coordination for the effective development of CI. Hence, the findings of this paper will help academic institutes to review their curricula and improve their internship coordination mechanism. It has implication for industry organizations in indicating knowledge and skills gap of entry-level professionals which could be filled through training. It may also invite other researchers in the country to focus on construction education for betterment of the CI. © 2019, Emerald Publishing Limited.
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    Assessment of consumption and availability of water in the upper Omo-Gibe basin, Ethiopia
    (Springer, 2020) Nesru, M.; Nagaraj, M.K.; Shetty, A.
    Understanding water balance components is imperative for proper policy and decision making, specifically in the upper part of the Omo-Gibe basin (UOGB) Ethiopia. The objective of this study is to explore the possibility of assessing consumption and availability of water using freely available satellite data and secondary data. Using twenty-three rain gauge stations data, a spatial average of rainfall was computed using the Thiessen polygon approach. Actual evapotranspiration (ETa) was estimated through the Surface Energy Balance System (SEBS). Input data used are, 16 clouds free Moderate Resolution Imaging Spectroradiometer (MODIS) images covering the study area for estimation of the spatial distribution of actual evapotranspiration covering the whole cropping year from the months of November 2003 to October 2004. Additionally, Priestly and Taylor’s approach was used to estimate reference evapotranspiration (ET0). For the study period, the result of estimated precipitation and ETa showed that the UOGB received 41,080 mm3 of precipitation, while 24,135 mm3 become evapotranspired. The assessed outflow from the basin is 17.6% of the precipitation and demonstrated that water is a scares resource in the UOGB. © 2019, Saudi Society for Geosciences.
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    Dimensions for improvement of construction management practice in Ethiopian construction industry
    (Emerald Group Holdings Ltd., 2020) Mengistu, D.G.; Mahesh, G.
    Purpose: The state of the different practices in construction industry determines its performance level. Hence, improving performance of construction industry needs assessing state of the practices in the industry and devising improvement intervention. The purpose of this paper is to measure improvement requirement level of different construction management practice areas and to identify the underlying improvement dimensions in Ethiopian construction industry. Design/methodology/approach: Questionnaire survey was developed for data collection based on a thorough literature review which yielded 28 construction management practice areas. Purposive sampling method was used to select respondents for the survey. Mean score was used to identify the required improvement level, and one sample T-test was carried out to identify significance of improvement requirement. Factor analysis was conducted to identify the underlying dimensions of the construction management practice areas. Findings: Findings indicate 27 areas need significant improvement. This shows the low level of adoption of good construction management practices in Ethiopian construction industry. Factor analysis resulted in the areas being grouped to four broad improvement dimensions, namely, project management, organization management, knowledge and risk management and project development and contract management. Originality/value: The findings provide information for appropriate action by the stakeholders to raise standards of adopted construction management practices. It also show areas of construction management which require more focused research in the context of Ethiopian construction industry. Considering the similarity of nature of construction industry problems in developing countries, the findings can be extended to similar countries. © 2019, Emerald Publishing Limited.
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    Trend and variability of hydrometeorological variables of Tikur Wuha watershed in Ethiopia
    (Springer, 2020) Ketema, A.; Dwarakish, G.S.
    The study assessed monthly, seasonal, and annual variability and trend of hydrometeorological variables for 1978–2017 of Tikur Wuha watershed in Ethiopia. The Mann-Kendall trend test and Sen’s slope estimator were employed for the trend and size of the trend, respectively. Besides, the coefficient of variation has been computed for variability analysis. The areal average annual rainfall exhibited an insignificant declining trend with a magnitude of 20.8 mm/decade at a watershed scale. The watershed has been suffering from irregular and erratic rainfall during the dry season. Temperature exhibited a statistically significant rising trend with minimum temperature rises faster than that of the maximum temperature. The streamflow of the Tikur Wuha River was found to be increasing at the rate of 21.16 MCM/decade. The increasing trend of streamflow without the corresponding increase of rainfall in the watershed needs further investigation. © 2020, Saudi Society for Geosciences.
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    Multi-variable calibration of hydrological model in the upper Omo-Gibe basin, Ethiopia
    (Springer, 2020) Nesru, M.; Shetty, A.; Nagaraj, M.K.
    The calibration of any hydrological model in any river basin is generally performed using a single hydrological variable. Spatially distributed hydrological modeling provides an opportunity to enhance the use of multi-variable calibration models. The objective of this study is to test the efficiency of satellite-based actual evapotranspiration in the HBV hydrological model to render the catchment water balance using multi-variable calibration in the upper Omo-Gibe basin in Ethiopia. Five years (2000–2004) meteorological data, streamflow, and actual evapotranspiration (ETa) based on remote sensing were used for calibration and validation purposes. The performance of the HBV model and the efficiency of SEBS–ETa were evaluated using certain calibration criteria (objective function). The model is first calibrated using only streamflow data to test HBV model performance and then calibrated using a multi-variable (streamflow and ETa) dataset to evaluate the efficiency of SEBS–ETa. Both model setups were validated in a multi-variable evaluation using streamflow and ETa data. In the first case, the model performed well enough for streamflow and poor for ETa, while in the latter case, the performance efficiency of SEBS–ETa and streamflow data shows satisfactory to good. This implies that the performance of hydrological models is enhanced by employing multi-variable calibration. © 2020, Institute of Geophysics, Polish Academy of Sciences & Polish Academy of Sciences.
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    Challenges in developing the Ethiopian construction industry
    (Taylor and Francis Ltd. michael.wagreich@univie.ac.at, 2020) Mengistu, D.G.; Mahesh, G.
    To ensure continual improvement in the construction industry’s performance, its challenges must be identified so that integrated solutions that suit the context can be provided. The Ethiopian construction industry, like that in most developing countries, faces challenges that impede its development. This paper assesses four categories of challenges facing the industry, based on their sources: variables emanating from role of government, resource related variables, those related to the nature of the industry and variables emanating from the vision of the industry itself for its own development. Data for the study were collected through a questionnaire survey. Professionals from different background, such as contractors, consultants, clients, regulatory authority and academics were engaged in the survey. Mean score was used to identify the perceived impact level of the variables. Significant variables were identified and factor analysis was conducted to identify the underlying dimensions of the different sources. The major challenges are identified as: (i) delay in construction industry development (CID) policy implementation and corruption; (ii) weak capacity of contractors and consultants; (iii) lack of collaboration and professionalism; and (iv) lack of benchmarking CID practice from role of government, resource related variables, nature of the industry and industry’s vision for its own development, respectively. Findings provide information that stakeholders can use to make informed decisions and critical interventions for the effective development of the industry. © 2019, © 2019 African Journal of Science, Technology, Innovation and Development.