Ethiopian Journals Online (EJOL)
Not a member yet
4332 research outputs found
Sort by
Analytical Hierarchy Process Model for Selecting Road Contractors: A Case of Ethiopian Roads Administration
Get PDFIn the construction industry, the successful completion of a project mainly depends on the performance and capability of the contractor. It is therefore understood that the success of a project may be compromised without an appropriate and reliable process for identifying the most suitable contractor. Commonly, many organizations select contractors primarily on the lowest bid offer, as it is simple and emphasizes cost efficiency. However, this approach often undermines other important factors. Hence, incorporating a multi criteria decision making approach ensures a more balanced evaluation that considers both bid price and other key criteria. This study explores the application of the Analytical Hierarchy Process as a decision-making model for contractor’s selection. A combination of descriptive and case study research design was employed to identify and prioritize the contractor selection criteria. An extensive literature review identified 23 contractor selection criteria, which were categorized into four main groups. A structured questionnaire was then used to collect primary data based on these criteria. Once the data is gathered, the criteria are ranked in order of significance and prioritized for use in the analytical hierarchy process model. The analysis revealed that past performance competency had the highest weight (38.56%) with a consistency ratio of 0.088, followed by technical competency (24.16%) and financial competency (20.42%). Management competency ranked lowest at 16.84%, with a consistency ratio of 0.0529. In summary,the proposed model enhances the contractor selection process by integrating multiple key competencies to evaluate contractors across broader criteria
Safety Evaluation of Reinforced Concrete Highway Bridges Under Overloaded Truck Traffic: A Data-driven Assessment using Static Weighing Station (sws) Records
Get PDFAssessing performance assessment of reinforced concrete (RC) highway bridges subjected to overloaded truck is important in maintaining safety and sustainability of transport infrastructures. These trucks cause threat to bridges and lead to deterioration if not managed. The framework of assessment consists of structural analysis techniques, load rating methodologies, condition assessment procedures, and risk evaluation criteria. Studies showed that bridges in Ethiopia are overloaded and hence, in this study, a comprehensive safety assessment of selected RC highway bridges subjected to overloaded truck is presented. Nine RC girder bridges found along the selected routes have been considered for investigation. To investigate the effects of overloaded vehicles on Ethiopian bridges, 51,900 actual truck loading data from three static weighing stations (SWS) were collected over a period of five years. Rating factors for bridges were determined based on legal loads, actual truck load data, and extrapolated load data, taking into account the estimated remaining service life of the bridges and possible future reinforcement corrosion. The results revealed that, on average, 16.3 % and 33.85 % of the trucks violated the limit set on national regulation and bridge formulas, respectively. In addition, the rating factors for the bridges were reduced by 30.18 % and 56.29 % for the actual truck load data and extrapolated load data, respectively, compared to the legal loads. The result showed the bridges’ performance is severely affected and hence enforcing the current law and developing appropriate mitigation strategies are recommended
Investigation of the Effect of Lime Treatment on the Soil Water characteristics curve of expansive Soils
Get PDFThe engineering behavior of natural untreated and compacted lime-treated expansive soils, which typically exist in a state of unsaturated condition, can be better-explained using concepts from unsaturated soil mechanics. The soil water characteristics curve (SWCC) is the key unsaturated soil property for obtaining unsaturated soil property functions (USPFs). However, there are limited studies on the effect of lime on the SWCC of lime-treated expansive soils. This study investigated the effect of lime on the SWCC of lime-treated expansive soils. The drying portion of SWCCs for untreated natural soil and lime - treated soil samples with three different lime contents (3 %, 6 % and 9 %) with 7 days of curing were studied. The SWCCs were determined by using pressure plate apparatus in the suction range of 0 – 1400 kPa. The shrinkage curve (SC) was also determined to evaluate the change in volume of the different soil samples. The experimental results indicate that SWCC is affected by lime treatment and there is a change in the SWCC parameters and in the shape and position of SWCC as the percentage of lime is changed. The SWCC of the lime-treated soil samples show a higher rate of desaturation as the lime content increases. The Air Entry Value (AEV) and residual water content of lime-treated soil decreases with increase in percentage of lime and the SWCC shifts towards the left side as the AEV decreases. The differences in AEV obtained from gravimetric- water-content-based SWCC (w-SWCC) and degree-of-saturation-based SWCC (S-SWCC) for the lime-treated soil samples were small when compared to the untreated natural soil sample.Keywords: Air-entry value, Expansive soil, Lime treatment, Shrinkage curve, Soil–water characteristic curve, Unsaturated soil
Spectrum Occupancy Predictions Using Deep Learning Algorithms
Get PDFThe fixed spectrum allocation (FSA) policy causes a waste of valuable and limited natural resources because a significant portion of the spectrum allocated to users is unused. With the exponential growth of wireless devices and the continuous development of new technologies demanding more bandwidth, there is a significant spectrum shortage under current policies. Dynamic spectrum access (DSA) implemented in a cognitive radio network (CRN) is an emerging solution to meet the growing demand for spectrum that promises to improve spectrum utilization, enabling secondary users (SUs) to utilize unused spectrum allocated to primary users (PUs). This study has addressed all the limitations of the previous studies by implementing a comprehensive approach that encompasses reliable spectrum sensing, potential candidate spectrum band identification, long-term adaptive prediction modeling, and quantification of improvements achieved in the prediction model. The Long-Short Term Memory (LSTM) Deep Learning (DL) model was proposed as a solution for this study to address the challenge of capturing temporal dynamics in sequential inputs. The LSTM model leverages a gating mechanism to regulate information flow within the network, allowing it to learn and model long-term temporal dependencies effectively. The dataset used for this study was obtained from a real-world spectrum measurement by employing the Cyclostationary Feature Detection (CFD) approaches in the GSM900 mobile network uplink band, spanning a frequency range of 902.5 to 915 MHz over five consecutive days. The dataset comprises a total of 225,000 data points. The five-day spectrum measurement data analysis yielded an average spectrum utilization of 20.47 %. The proposed model predicted the spectrum occupancy state for 5 hours ahead in the future with an accuracy of 99.45 %, improved the spectrum utilization from 20.47 % to 98.28 % and reduced the sensing energy to 29.39 % compared to real-time sensing
Effective Cultism Management Techniques as Perceived by Staff and Students in Higher Education, A Case of Study of Federal College of Education (Technlcal) Gombe Nigeria
No full textThe Link between N.ational Education and Training to Economic Performance Is It all too Obvious to be Taken for Granted
No full text
Attempts at Educational Reform in Ethiopia: A Top-Down or a Bottom-Up Reform? Seyoum Tefera, Ethiopian Journal of Education, Vol. 16, No.1, 1996, pp. 1-37 Reviewed by The Ministry of Education
No full textThe major purpose of this Paper is to further depict and convey the right picture and message of the new and operational "Education and Training Policy" to general readers. This Paper also attempts, through all possible means, to respond to some of the not well-~hought-out statements reflected on the ETHIOPIAN JOURNAL OF EDUCATION (December, 1996) under the title "Attempts at Educational Reform in Ethiopia: A Top-down or a Bottom-up Reform?" authored by Dr. Seyoum Tefera, an Associate Professor, at the Department of Educational Administration, Addis Ababa University. This Paper shall not, under any circumstances, attempt to foolhardly engage in re-incriminations. It reflects on the existing educational reality. On the basis of the evolutionary. development of the Ethiopian educational · system, the Paper also attempts to historically trace the tortuous path that the Ethiopian education system has traversed through in the da~k past. Finally, in drawing a conclusion, the Paper views the steps taken by the Ministry of Education of the FDRE to bring about a bottom-up democratic education reform,' as opposed to top-down