College of Technology and Built Environment

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    2D Hydrodynamic Modeling of Rib River Flooding
    (Addis Ababa, 2011-10) Shiferaw, Muluken; Michael, Yonas (PhD)
    Flood occurs repeatedly in Ethiopia and cause tremendous losses in terms of property and life, particularly in the lowland areas. The majority of flood disasters’ victims are poor people living in nearby stretch of floodplain. Therefore, the study was carried out to perform floodplain analysis and risk assessment of Fogera and nearby areas. This research involves the integration of 2D Structured Mesh Generator (CCHE-MESH) and hydrodynamic numerical model (CCHE2D model) with Geographic Information Systems (GIS) to develop a regional model for floodplain determination and representation. The study describes the flood extent and depth in the area for flow condition derived from the historical flow data of the Rib River. Triangulated Irregular Network (TIN) was prepared from shape file generated from spot elevations of the floodplain through field survey data and the DEM of the study area in ArcGIS. Triangulated Irregular Network (TIN) is converted to an ASC II format, which is supported by the CCHE-MESH and CCHE2D model. Boundary condition for the inlet is specified as total discharge and discharge hydrograph for steady and unsteady simulation respectively and for the outlet a constant water level of Lake Tana (1788m) is specified as a downstream BC which allows for simulation of the free flow condition at the river outlet. Initial conditions are defined based on information on gauges or through introducing a so called warm-up that precedes the actual simulation period and boundary conditions are generally specified from hydrometric data such as time series data of discharge and stage or simulated discharge hydrograph. Maps of flood Extent, Level, Depth and Velocity are developed using 100 years return period flood. The Flood has the inundation area of 47.13km2 while the simulated flood extent has flood depths less than 5.9m. The depth between 5.9m and 2m is located along the river channel and on the pond which is located south of the rib river. However, the depths below 2m exist largely on the flood plain which extend 4 km and 3 km outside right bank and the left bank of the main river respectively. The simulated water level ranges between 1798.4m ASL at the upstream and 1788m ASL at the downstream end of the main river. The simulation result indicates much of the flooding occur in the middle part of the river where the flow behaviour is mainly dominated by the inflow from the Rib River. Most of the areas around the flood plain are cultivated land with less proportion of Agro-pastoral, Marsh and Pastoral. 85-90% of the flood inundated areas are covered by agricultural land. The remaining 10-15% is covered by Agro-pastoral near inlet to Lake Tana.
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    3D Gravity Inversion for Mineral Exploration Over Southern Green-stone-Belts of Ethiopia
    (Addis Ababa University, 2022-03) Girum, Ashenafi; Tulu, Besha (PhD)
    Mainly this study aimed to investigate subsurface geology of the southern green stone mineralization zone for evaluation of gravity inversion is how effectively detecting high-density mineralization. Throughout the project, three main tasks have done: the first task was carrying out necessary correction for observed gravity data. Under this stage three main outputs were obtained: Bouguer gravity anomaly, regional Bouguer anomaly and residual Bouguer anomaly. The target information is represented by residual anomaly therefore it is became the final data for inversion process. The second task was minimizing Tikhonov’s cost function and carrying out inversion with the help of a conjugate gradient algorithm after formulated sensitivity matrix. The interpretation process was the last step of the work. The results obtained from the inversion process are demonstrated in two forms: the first one was a horizontal slice that illustrated the trend of mineralization in a horizontal plane and the second was density contrast model in a vertical plane that illustrated at four different lines of cross-section. In the horizontal density contrast model, the pixels value of high-density contrast under mineralization zone revealed 76.8% of pixels made a good agreement with the mineralization history of the target region. In addition, 90.3% of high-density contrast agreed with the location of metallic minerals in the region. In contrast, very low-density contrast in the region scored 3.77%. Therefore the inverted density contrast model well demonstrated the signature of mineralization in the target region. The vertical slice of the density contrast model indicated the depth condition of the high anomalous density region. Thus cross-section profile 1 up to 4 maximum depth and percentage of high density contrast above 600m depth are 1309.464m, 1089.866m, 847.72m, 661.0338m and 81.5%, 72%, 86.3%, 99.1% respectively. The vertical patterns of high-density contrast are correlated with the information obtained from a borehole at the mineralization zone. From such results and validation, I concluded: gravity anomaly inversion is a good tool to detect the position, depth extent, and the trend of the significant anomalous region.
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    5D Planning, Scheduling and Control of Construction Projects by Integrating Project Management Software and GIS
    (Addis Ababa University, 2017-12) Sitota, Girma; Abebe, Dinku (Prof.)
    Construction industry can be deemed as the most vital driving force of a country. Construction of vast projects such as township, stadiums, and dams is a challenging task both in terms of managing complexities of the project and addressing the demands of all stakeholders. Its success or failure largely depends on cost effectiveness, time-bound delivery, quality and amount of resources available throughout the lifecycle of the project. This clearly turns the focus towards effective construction project management. Today’s demand of construction industry requires highly accurate planning, scheduling and management of the process of a project which can enable the overall optimization of cost, time, and resources. With the advances in information technology, its use is being constantly explored in the area of construction planning and monitoring. The aim of this study is to demonstrate the methodology of integrating Geographic Information System (GIS) with construction project management to provide a better solution for optimization and real time monitoring of the progress of a project. GIS is a computer based tool and being used extensively to solve various engineering problems involving the use of spatial data. The technology provides capabilities to solve problems involving creation and management of data, integration of information, visualization and cost estimation to which most of the construction management software are lacking. In spite of the growing popularity its complete potential to the construction industry has not been realized. Integration of GIS and Project management might assist a planner in a better perception of a project as well as in the integration of other parties’ activities in the planning process. It will provide a common basis of understanding and communication among stakeholders. This helps in reducing construction errors occurring on sites and thereby reduces the amount of administrative time. In this research paper a review of up-to-date work on the applications of GIS technology in construction industry is presented. Methodology to generate 3D view of a building and to represent construction schedule within GIS environment is also discussed. With this, integration of GIS and Project Management is developed using AutoCAD, MS-Excel, ArcGIS, and Visual Studio to assist construction managers in controlling and monitoring a construction progress. With time as the fourth dimension, the progress of construction task can be displayed as 4D (3D + time) view. The 5D (3D + time + cost) model of progress monitoring is beneficial to all stakeholders and can be opted as the future of planning and monitoring in the fast developing construction industry. A case study of one story building is selected for the purpose of presenting the integrated tool for progress monitoring. Ultimately, an easy to use Graphic User Interface (GUI) named as “5D Construction Monitoring Application” is developed to enable project participants have an idea of the current status of a project at run-time. The paper explores the potential of GIS environment in developing a construction project information system for rate analysis; and safety and quality control recommendation. It also suggests that the proposed GIS based methodology may replace manual methods used to extract information from the available database and can be easily updated as most of the information is in digital format. Successful project control is a challenging responsibility, but the job becomes easier when it is complimented with visualization of information. The propositions presented herein could facilitate and accelerate this trend, and as well provide means of measuring the success of implementation of 5D planning in construction projects and be a basis for further research.
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    (7,3) Maximum - Length Binary Cycle Code Applied to Single Channel Digital Communication System for Error Correction
    (Addis Ababa University, 1996-06) snegash, Yohanne; Alemu, Ketema(phD)
    This paper presents the design and hardware implementation of the (7,3) maximum-length binary cyclic code applied to a single channel communication system. In hardware implementation of the system a PC with a data acquisition board with time <- sharing for interfacing the analog signals. A 12-bit digital output of the PC is divided into blocks of 3-bits for processing by the channel encoder The implementation of the system is carried out using shift registers and logic gates. A sinusoidal input waveform is applied to the system input and a circuit designed with a combination of D-type flip-flops and logic gates is used to introduce the effects of a single-random-error and a double-adjacent-burst error to observe the performance of the system. The code resulted in good performance in correcting a single-random-error and a double-adjacent-burst-error.
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    A Comparative Analysis of Power Amplifier Types in Massive MIMO Systems for 5G Networks.
    (Addis Ababa University, 2025-03) Gamachu Tafari; Yihenew Wondie (PhD)
    Class AB, Doherty, and Envelope Tracking Power Amplifiers (ETPA) are the three types of power amplifiers that are thoroughly compared in this thesis in the context of 5G networks. Current communication standards require power amplifiers to achieve high efficiency over increasingly larger dynamic ranges and bandwidths while maintaining strict linearity criteria. The study uses key criteria like power-added efficiency, linearity, gain, and output power to evaluate their performance. Simulations were conducted using MATLAB and the Advanced Design System to evaluate amplifier properties under various settings, including the use of Digital Pre-Distortion to improve nonlinearity. The results showed that Class AB amplifiers achieved PAE of 51.090 % and improved AMAM Conversion. Excellent back-off efficiency and significant advantages in high-power scenarios are exhibited by Doherty amplifiers, especially when DPD integration is employed for enhanced linearity. Despite achieving 70% PAE and demonstrating superior efficiency over a broad dynamic range, envelope tracking amplifiers require complex design due to their reliance on dynamic voltage control. By balancing the trade-offs between linearity and efficiency, this study determines the optimal amplifier topologies for 5G networks that are both high-performance and energy-efficient. These discoveries contribute to the advancement of the technology by revealing the future applications of power amplifiers in wireless communication systems.
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    A Comparative Study of Limits on Normalized Axial Loads of Es-En 1998:2015 With Other Current Major Building Codes on Columns
    (Addis Ababa University, 2024-04) Abel Negussie; Adil Zekaria (PhD)
    Axial loads highly affect the behavior of reinforced concrete members, such as failure mode, yield curvature, ultimate curvature, curvature ductility, beam-column joint, etc. In order to limit the adverse effects of axial loads, Ethiopian Standards based on Euro-Norms limits normalized design axial compressive loads. This research explores the basis for these limits and then compares them with other major codes and standards. The primary aim for these limits is for the axial loads not to exceed loads at balanced failure, . To study the balanced conditions, a series of interaction charts were constructed with the confinement effect of transverse reinforcement on concrete considered. The three main parameters for the charts are the distance of compression reinforcement from the extreme compression fibres normalised with respect to effective depth, ⁄ , mechanical reinforcement ratios, , and mechanical volumetric ratio of confining reinforcement, . Sectional properties, i.e., yield curvature, ultimate curvature and curvature ductility, under the obtained balanced axial loads were compared to their perspective limits. It was concluded that is highly affected by , and to a lesser extent by and . It has an inversely proportional relationship with both , and . Fifteen different column section was also considered as an example, and their results are in alignment with the interaction charts. From the results obtained, it can be concluded that the limits can be more directed for values of . This is especially the case for column sections having lower values of which show a greater load capacity than the set limits.
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    A Comprehensive Through Lane Saturation Flow Rate Model for Signalized Intersection by Considering Illegal Crossing Pedestrian Effect at Selected Intersections in Addis Ababa
    (Addis Ababa University, 2025-06) Ephrem Bogale; Yonas Minalu (PhD)
    One significant element influencing urban traffic performance networks is signalized intersections. It can guarantee safe and efficient traffic flow through the crossings and optimize their capacity. Researchers have been examining signalized junction capacities for a long time. However, the pedestrian effect has not been well studied. Two perspectives are used to analyze the effects of pedestrians: 1) Traffic flow is disrupted by pedestrians; 2) Speed and saturation flow rate are reduced as a result of pedestrian interference. One of the crucial aspects of analyzing the capacity of signalized junctions that is influenced by several circumstances is saturation flow rate. Geometric conditions, traffic conditions, driver conduct, traffic light timing, gradient direction, number of lanes, lane width, volume and kind of turning actions, and pedestrian movement are some of the effective aspects that HCM identifies as determining saturation flow. Walking is a popular form of transportation in Addis Ababa, and people who cross the street when green traffic light is on have an impact on traffic flow. We chose five Addis Ababa signalized crossings to examine how pedestrians affect signal capacity. St. Estifanos, Banko de Roma, Ayer Tena, Jemo Michael, and Saris Abo. Their current functional status, being four-legged, high pedestrian flow, High traffic volume, least interference to entry and exit traffic due to parking activities were the criteria for their selection. Video graphic method was used to gather pedestrian and traffic data from the field. The hours of 8:00 AM to 9:00 AM and 3:00 PM to 4:00 PM were used to gather traffic data. To develop a suitable saturation flow equation for estimating capacity and designing traffic infrastructure for heterogeneous traffic, the heterogeneous traffic must be transformed into homogeneous using a common unit, called the PCU. The dynamic PCUs have been computed in this study, which takes vehicle size and speed into account as key variables for PCU component estimation. The Method adopted in this thesis work o generate a model equation to calculate PCU is Speed-Area method which is developed by Dr. Satish Chandra, according to Chandra’s method (1) This study presents a saturation flow rate analysis of selected Addis Ababa's signalized crossings under mixed traffic situations. In order to collect information on traffic volume and speed on city roads, a video graphic technique was used to determine the saturation flow. The headway which is the amount of time that passes between successive cars crossing the stop line had calculated and then 3600 divided by this headway to get the saturation flow rate. Measurements of saturation flow rates generally show 2.47% - 29.53% lower values than those currently used in the Highway Capacity Manual. The saturation flow rates at the local crossings will be overstated if HCM's suggested value is implemented in study intersections; the presence of pedestrians didn’t show significance in through lane saturation flow rate. A general model for the saturation flow rate analysis should have been created in the spot while we design and maintain an intersection in Addis Ababa.
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    A Deterministic Approach to Tri-Radical Amharic Verb Derivatives Generation
    (Addis Ababa University, 2022-02) Samrawit Kassaye; Yalemzewd Negash (PhD)
    Morphological synthesis or generation is a process of returning one or more surface forms from a sequence of underlying (lexical) forms. Today, synthesizers of different kinds have been developed for languages that have relatively wider use internationally. Amharic is the second most populous Semitic languages after Arabic. But it is not exploited in the digital world. In this research paper, a rule-based approach to morphologically derive or generate Amharic words from tri-radical verbs to finally generate rich Amharic lexicon is elaborated. This work utilizes two data sources namely Amharic word list and tri-radical verbs. The Amharic word list file contains more than 450,000 unique Amharic words. The tri-radical verb data source contains more than 350 unique tri-radical verbs. The proposed method works towards identifying rules from existing Amharic words after analyzing with tri-radical verbs. The new feature identified is applying index changing the letter of tri-radical verbs. Index changing (adding vowel to consonant letters) is one of the approaches used in morphological derivation of Amharic words from root(stem) words. After index changing of the tri-radical verbs, the index changed words will be searched in the Amharic word list file. If the index changed words are found directly or part of word with prefix and/or suffix, the pattern of the word with respect to the root verb and index changed words will be captured. From the pattern captured morphemes are extracted and rules are identified. 85,115 unique rules are identified. While identifying rules, the frequency of every rule is recorded in order to evaluate the efficiency of each rule. A memory-based machine learning approach applied to evaluate the frequency of the rules. From the 85,115 rules, the prefix of 29,776 rules and the suffix of 32,401 rules are wrong, and 11,390 rules are discarded by wrong index changing process. The rules identified showed the accuracy of 0.99, average precision of 0.88 and average recall of 0.85. Based on these rules, a comprehensive set of derivatives for tri-radical Amharic verbs were generated and end up having a rich Amharic Lexicon.
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    A gravimetric method to determine horizontal stress field due to flow in the mantle in East Africa Great Rift Valley
    (Addis Ababa University, 2023-07) Abenezer Getinet; Andinet Ashagire (Phd)
    The gravimetric approach has been widely used to determine the stress field of subsurface geology of the earth crust. Mainly this study aimed to determine lithospheric shear stress in the Earth’s mantle and its temporal changes caused by geodynamical movements. The gravimetric approach is applied, to evaluate the stress at the base of lithosphere and to detect changes in stress using static gravity field model EGM08 and GRACE monthly solutions respectively. In addition to the static gravity field data some physical information about topographic height, crustal thickness, and lithospheric thickness are incorporated in this method. As a result, more geophysical information and data are applied for computation of horizontal lithospheric stress in this approach. To do so, depth of the base of lithosphere determined by subtracting topographic height from lithospheric thickness is needed, thus the lithospheric shear stress component computed at the base of lithosphere. Moreover, the comparison of lithospheric shear stress using different static gravity field models are performed. The estimated horizontal shear stress at the base of the lithosphere throughout the study area revealed 55.68% of the stress is oriented in a northward direction and the remaining 44.32% is oriented in the southward direction; 44.41% of the stress is oriented in an eastward direction and the remaining 55.59% is oriented in the westward direction: and the result of the estimated horizontal shear stress magnitude ranges from ≈ 0.04 MPa to ≈ 15.32 MPa. Furthermore, the estimated horizontal shear stress components show good agreement with the tectonic boundaries and the location of stress regimes in the WSM2016 database, as well as the seismic events in the study area.
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    A Heuristics and Discrete Event Simulation for Optimized Layout Design in Agricultural Machinery Maintenance - A Case Study of Wereta International Business Plc.
    (Addis Ababa University, 2024-07) Fitsumberhan Hailemeskel; Ameha Mulugeta (PhD); Ayele Legesse ((Mr.) Co-Advisor
    Agricultural machineries play a vital role in agricultural processes and help in the production of food and non-food items. The efficient layout of agricultural machinery maintenance facilities is crucial for minimizing process times and maximizing throughput. This paper deals with the development and optimization of an agricultural machinery maintenance facility using discrete event simulation considering Wereta International Business Plc.’s agricultural machinery maintenance facility layout as a case. The development of the facility layout is done in a way that introduces flexibility of departments and also that combines the different services given in the facility, maintenance, training (customer & staff) and pre-delivery inspection processes. The research tries to construct a new facility layout that decreases the travel distance, considers the relationship between departments using the CORELAP facility layout construction method. The newly constructed facility layout has been optimized using facility layout improvement technique, CRAFT (excel add-in) to further enhance the optimality of the facility layout by enhancing the material flow between departments to minimize the material handling cost. Finally, an improved facility layout, with 15 departments that include main and supporting facilities and also combines the services and training facilities is developed. The proposed facility layout reduces that has been constructed from scratch and then optimized decreases the distance traveled between departments by 2,015.11 meter (a reduction of 33.66%) and the total monthly material handling cost by 531,093.14 Birr per month (a reduction of 86.85%). The entity output of the existing system is 40 units and for the proposed layout, the entity output is 67, an increase by 67.50%. Also, the system output from the existing simulation model is 125.30 units and the proposed layout simulation modeling system output increased by 58.85% to 199.04 units.
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    A Hybrid Approach to Strike a Balance of Sampling Time and Diversity in Floorplan Generation
    (Addis Ababa University, 2024-05) Azmeraw Bekele; Beakal Gizachew. (PhD)
    Generative models have revolutionized various industries by enabling the generation of diverse outputs, and floorplan generation is one such application. Different methods, including GANs, diffusion models, and others, have been employed for floorplan generation. However, each method faces specific challenges, such as mode collapse in GANs and sampling time in diffusion models. Efforts to mitigate these issues have led to the exploration of techniques such as regularization methods, architectural modifications, knowledge distillation, and adaptive noise schedules. However, existing methods often struggle to effectively balance both sampling time and diversity simultaneously. In response, this thesis proposes a novel hybrid approach that amalgamates GANs and diffusion models to address the dual challenges of diversity and sampling time in floorplan generation. To the best of our knowledge, this work is the first to introduce a solution that not only balances sampling time and diversity but also enhances the realism of the generated floorplans. The proposed method is trained on the RPLAN dataset and combines the advantages of GANs and diffusion models while incorporating different techniques such as regularization methods and architectural modifications to optimize our objectives. To evaluate the effect of the denoising step, we experimented with different time steps and found better diversity results at T=20. The diversity of generated floorplans was evaluated using FID across the number of rooms, and the results of our model demonstrate an average 15.5% improvement over the state-of-the-art houseDiffusion model. Additionally, it reduces the time required for generation by 41% compared to the housediffusion model. Despite these advancements, it is acknowledged that the proposed research may encounter limitations in generating non-Manhattan floorplans and when dealing with complex layouts.
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    A Lightweight Model for Balancing Efficiency and Precision in PEFT-Optimized Java Unit Test Generation
    (Addis Ababa University, 2025-06) Sintayehu Zekarias; Beakal Gizachew (PhD)
    Software testing accounts for nearly 50% of development costs while being critical for ensuring software quality, creating an urgent need for more efficient testing solutions. This work addresses this challenge by developing an innovative framework that combines Parameter-Efficient Fine-Tuning (PEFT) techniques with transformer models to automate Java unit test generation. The study systematically evaluates three PEFT approaches—Low-Rank Adaptation(LoRA), Quantized LoRA (QLoRA), and Adapters—through a rigorous methodology involving specialized assertion pretraining using the Atlas dataset (1.2M Java method-assertion pairs), PEFT optimization, targeted fine-tuning with Methods2Test (780K test cases), and comprehensive validation on the unseen Defects4J benchmark to assess cross-project generalization. Experimental results demonstrate that LoRA maintains 92% full fine-tuning effectiveness (38.12% correct test cases) while reducing GPU memory requirements by 17% and improving generation speed by 23%. QLoRA achieves even greater efficiency with 36% memory reduction, making it particularly suitable for resource-constrained environments. However, evaluation on Defects4J, assessing cross-project generalization, showed that LoRA achieved 43.1% correct assertions (compared to a full fine-tuning baseline of 46.0% on Defects4J), indicating a minor reduction in generalization alongside the efficiency gains. Despite these promising advancements, it’s important to note that our findings are currently contextualized by the Java programming language and the specific datasets employed in our experiments. These findings provide valuable insights for the implementation of AI-powered test generation in practice, highlighting both the potential of PEFT techniques to reduce testing costs and the need for further research to address the nuances of maintaining test quality across diverse projects.
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    A Masters Project on Utilization and Quality Enhancement of Local Kaolin Clay Minerals Through Beneficiation
    (Addis Ababa University, 2023-02) Abiyot Ayalew; Anteneh Marlign (PhD); Meseret Aregahegn:-Co-Advisor
    Recently, some researchers labeled industrial minerals as ‘Development Minerals ‘because of their crucial role for fast local economic development and their necessity in the industrialization. The commercial term “Kaolin “is one of the most versatile industrial clay minerals composed essentially of kaolinite (Al2O3.2SiO22H2O). Kaolin What we call it as “China clay” have been found in Ethiopia as huge reserve estimated (20 million tons), throughout in the different parts of country. However, manufacturing industries import commercially value-added Kaolin from foreign countries due to the low qualities of local kaolin which have major impurities. The impurities of Kaolin from literatures and from XRF characterization of Raw Kaolin (RK) are quartz, mica, feldspar, iron oxide and titanium oxide minerals. Here my interest was to improve the qualities of this local kaolin through physical, thermal and chemical beneficiation to substitute imported commercial Kaolin. The two principal objectives of kaolin refining were the removal of impurities and the production of the desired particle-size distributions. Possibly to meet some industrial requirements, the coloring impurities (mainly iron oxides and other small amounts of fuxing components) must be removed. Based on the XRF analysis, the raw kaolin ore from AlemTena, Ethiopia containing 64.135 wt% SiO2, 25.747 wt% Al2O3, 4.838 wt% Fe2O3, and 8.22 wt% loss of ignition (LOI). Then it was physically beneficiated, chemically leached, and thermally treated for possible industrial use, especially for ceramic applications. The leaching experiments were carried out using oxalic acid solutions as leaching reagents for the iron extraction and colour enhancement process. A substantial reduction of iron oxide (4.838 to 3.107 wt %) and silica (64.135 to 57.285 wt%) SiO2 on the other hand a substantial increment of alumina (25.747 to 33.662 wt%) Al2O3 from the raw kaolin was observed at operating conditions of 2.0 M oxalic acid, the temperature of 90 °C, and contact time of 120 min. From Chemically leached kaolin we observed a significant whiteness and brightness. In other way the thermally treated kaolin was observed an increment of iron oxide (4.838 to 6.605 wt %) and also it lost its crystalline structure and becomes an amorphous phase but still its alumina and silica contents improved. Generally, from my study I understood that, the physically beneficiated, chemically leached, and thermally treated kaolin raw material can used to fabricate low-cost kaolin-based ceramic products.
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    A Structured Framework for Email Forensic Investigations
    (Addis Ababa University, 2025) Biruk Bekele; Henok Mulugeta (PhD)
    Email forensics investigations become vital regarding legal, cybersecurity, and corporate challenges. However, most of the existing frameworks are suffering from inefficiency problems, data integrity, and handling such diverse data sources with complexity, considering encrypted emails and metadata. This thesis applied the Design Science Methodology to develop a structured framework that enhanced efficiency and effectiveness in email forensic investigations. These specifically deal with data quality, diversity in data management, and integrity of evidence. Among others, one key component is case management, which systemizes and keeps track of the investigation from the very outset to the last step in an appropriate manner and ensures each step is conducted methodically. The framework comprises key phases: case management, governance, identification, preservation, classification, analysis, presentation and compliance that address critical challenges such as ensuring data quality, managing diverse data sources, and maintaining evidence integrity. Case management forms the core part of the proposed framework for organizing, tracking the investigation process from start to finish in order ensuring that evidence is handled properly, and all phases are executed in a systematic manner. It integrates open-source tools, case studies of different varieties, and best practices to be relevant to different real-world scenarios. The effectiveness of the artifact can also be demonstrated in practical application, performance being measured in terms of speed of investigation, data quality, accuracy, and user satisfaction, among other metrics. This research underscores that the suggested framework decreases the time of investigation, reduces the rate of errors, increases the quality of data management, and guarantees the effective access of various data sources. This thesis contributes on both practical and theoretical levels, guiding practitioners and researchers comprehensively in the area of digital forensics to bring current email forensic investigations into a more efficient, accountable, and adaptable condition.
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    A Study on Optical Quality Enhancement of Alpha-Alumina/Titania Pearlescent Pigment Via Insitu Ph Control
    (Addis Ababa University, 2023-10) Buziye Guye; Anteneh Marilegn (PhD)
    Pigment is a material that changes the color of reflected or transmitted light as the result of wavelength- picky immersion. During high-temperature calcination, there is a problem with the thermal expansion coefficient mismatch between mica and titania and the resulting thermal stress and crack formation. Thermal stress and crack formation is an issue during high-temperature calcination. Formation of cracks in the coating layer results in the scattering of light and the consequent decline of pearl luster. Various researchers have conducted a study on the low temperature rutile phase formation; however, the attempts have resulted in higher rutile phase fraction on the final coating but in most cases with compromised optical quality. In this study, α-Al2O3 platelets of average particle size ⁓ 10μm have been synthesized to be used as a substrate for the pearlescent pigment. Coating of TiO2 on the surface of the synthesized α-Al2O3 was performed via co-precipitation method. Urea was utilized as a hydrolyzing and pH-regulating agent along with TiOSO4 as a precursor to TiO2The sample with lower oxysulfate:urea ratio (i.e. strongly acidic synthesis media) resulted in higher rutile phase fraction (41.5%) while the other two samples, where the oxysulfate:urea ratios are 1:25 (i.e. close to neutral pH) and 1:50 (i.e. strongly basic synthesis media), resulted in extremely lower rutile phase fraction, 2.9% and 1.4% ,respectively. The coated samples' morphology showed that the entire coating was smooth. When compared to samples with lower rutile phase fractions, those with greater rutile phase fractions exhibit higher reflactance in the visible area, according to the optical performance of the samples. The color value measurments have also revealed that, samples with higher rutile fractions exhibit higher lightness values (L*) in comparison to those with lower rutile phase fractions. The study showed that, in general, controlling the rutile phase fraction by adjusting the pH of the synthesis media using in-situ urea decomposition was effective in producing TiO2 coatings with higher rutile phase fractions and better surface smoothness, which in turn results in higher optical quality.
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    A Study on Optical Quality Enhancement of Alpha-Alumina/Titania Pearlescent Pigment Via Insitu PH Control
    (Addis Ababa University, 2023-10) Buziye Guye; Anteneh Marelign (PhD)
    Pigment is a material that changes the color of reflected or transmitted light as the result of wavelength- picky immersion. During high-temperature calcination, there is a problem with the thermal expansion coefficient mismatch between mica and titania and the resulting thermal stress and crack formation. Thermal stress and crack formation is an issue during high-temperature calcination. Formation of cracks in the coating layer results in the scattering of light and the consequent decline of pearl luster. Various researchers have conducted a study on the low temperature rutile phase formation; however, the attempts have resulted in higher rutile phase fraction on the final coating but in most cases with compromised optical quality. In this study, α-Al2O3 platelets of average particle size ⁓ 10μm have been synthesized to be used as a substrate for the pearlescent pigment. Coating of TiO2 on the surface of the synthesized α-Al2O3 was performed via co-precipitation method. Urea was utilized as a hydrolyzing and pH-regulating agent along with TiOSO4 as a precursor to TiO2The sample with lower oxysulfate:urea ratio (i.e. strongly acidic synthesis media) resulted in higher rutile phase fraction (41.5%) while the other two samples, where the oxysulfate:urea ratios are 1:25 (i.e. close to neutral pH) and 1:50 (i.e. strongly basic synthesis media), resulted in extremely lower rutile phase fraction, 2.9% and 1.4% ,respectively. The coated samples' morphology showed that the entire coating was smooth. When compared to samples with lower rutile phase fractions, those with greater rutile phase fractions exhibit higher reflactance in the visible area, according to the optical performance of the samples. The color value measurments have also revealed that, samples with higher rutile fractions exhibit higher lightness values (L*) in comparison to those with lower rutile phase fractions. The study showed that, in general, controlling the rutile phase fraction by adjusting the pH of the synthesis media using in-situ urea decomposition was effective in producing TiO2 coatings with higher rutile phase fractions and better surface smoothness, which in turn results in higher optical quality.
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    A Study on the Performance of Housing Projects: A Post Project Evaluation of Branch Two 40/60 Housing Projects in Ethiopia.
    (Addis Ababa University, 2025-05) Helen Woldeselassie; Abebe Dinku (Prof.)
    Integrated Housing Development Program was created as part of the nation's economic development strategy, In order to boost local companies, encourage the use of locally produced building materials, and provide job opportunities. The 40/60 housing scheme is one of the initiatives. The Addis Ababa city administration started the 40/60 saving housing project at reasonable costs for middle-class city citizens in order to address the housing issue. The country's largest city Addis Ababa, is home to a sizable population, and it is anticipated that this population will continue to grow in the near future. This has occasionally led to an increase in the demand for housing, which has resulted in the most complex socioeconomic issues in the city. Since 2013, the IHDP lottery registration system has been inaccessible to new applicants, as there is a waiting list that currently stands more than 800,000. Additionally, previously scheduled IHDP construction developments have been postponed.Ex post evaluation is an assessment technique that emphasizes the project's long-term results. The lack of a system for evaluating building performance is one of the causes for our inability to obtain crucial data on our buildings, which leads to reoccurring errors and ineffective projects. Project assessment can be helpful in demonstrating openness and accountability as well as in allowing lessons learned to be shared in the construction of knowledge and expertise. In this regard this research is conducted to evaluate the performance of the 40/60 housing projects. Beside observed information this research identify and analyse data to determine the performance of the housing projects, to identify the underperformance areas in the housing projects, to investigate factors contributing to underperformance of the housing projects and to identify the post occupation issues or defects of the housing projects.The data is collected from customers, brokers and employees of the organization that are involved in the building construction projects through an interview, questioner , project reports and documents. The housing projects under this research construct in total of 14,724 houses and 4932 shops. Among these buildings 158 of them are delivered and 7,963 numbers of keys are transferred to the owners. In total 737 people benefited from this project employment opportunity and among them 139 of them are women. This projects helps landlords in creating wealth And also help as an option for the peoples who can’t afford the rent and the cost of real-estate apartments. However there is a difference between the number of blocks constructed and transferred, there is also price increment on the buyers in each round which makes accountability and affordability of these condominium houses questionable and also Water leakage, dampness and mold growth are among the common quality problems observed in these projects. Delayed design, delayed contractor payments and time estimates that are unrealistic compared to the actual work are some of the reason mentioned for the observed delays. And the reasons for the difference in quantity among the materials given to the contractor by the government and actual consumption were the standard being not prepared back then, due to inefficient uses of material by contractors, in some cases due to robbery issues and also the change in supervisor in different times from the client side causing a gap in information.
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    A Top- Down Chart Parser for Ge’ez Sentences
    (Addis Ababa University, 2024-12) Nega Meareg; Surafel Lemma (PhD)
    Parsing is the process of breaking down a sentence into its part of speech or words like verb, noun, preposition, adjective and so on. Parsing plays an important role in enhancing the performance of numerous natural languages processing (NLP). Here this work is designed to parse geez language on the approach of a Top-Down chart Parser for Geez language sentences using the context free grammar rule (CFG). We reviewed various parsing approaches for different languages, to achieve our objective. How ever, Geez language parsing remains challenging dueto the absence of annotated dataset. To address this gap, we collected a dataset for sentence parsing from the well-known book Mezumere Dawit.Given the lack of the lack of pre-existing labled data; we collaborated with a language expert (Amanuel), an instructor in the Geez Department at Aksum University, to ensure lingustic accuracy. The expert prepared the dataset in a format suitable fstablished grammatical rules ford sentence construction based on verb and noun phrase structures, and manually parsed the sentences. This study presents a Top-Down parsing approach for Geez language sentences; addressing the challenges posed by the language’s unique morphological and synthetic structures. Using a dataset of 500 sourced from the book ’Mezumure Dawit” the parser correctly parsed 470 sentences, achiving a parsing accuracy of 94%. The results were validated through the manual parsing, where 490 sentences were parsed manually, with 470 sentences matching the parser’s output. The performance of the parser was evaluated using standard metrics, including precision, recall, F1 score, and Experimental results show the effectiveness of the proposed method in parsing Geez language sentences. Thrid study contributes a foundational step towards computational processing of Geez language, with potential applications in machine translation and historical analysis.
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    A Trilingual Android Application with Automatic Malaria Detection from Microscopic Images of Red Blood Cells
    (Addis Ababa University, 2023-12) Berihun Nigussa; Dawit Assefa (PhD)
    Malaria, which is a mosquito-borne blood disease caused by Plasmodium parasites, is one of the virulent infectious diseases affecting human beings and other animals since antiquity. Even though there were promising progresses in the reduction of malaria morbidity and mortality in the past two decades before the outbreak of COVID-19, the latest two reports of theWorld Health Organization (WHO) statistics indicate that malaria has been overlooked due to the COVID pandemics. Malaria is still prevalent specifically in low resource setting areas such as the sub-Saharan African countries, including Ethiopia. WHO reported that there were 229 million new cases of malaria and 409,000 deaths globally in 2019, alone. Whereas in the year 2021, the morbidity and mortality was reported to rise up to 247 million and 619,000, respectively. Timely diagnosis and treatment as well as good awareness about the disease play a major role to combat malaria. In the current project work, it was intended to design and develop a multi-lingual Android App that offers useful information about the malaria disease and is capable of automatically detecting malaria infected red blood cells (RBCs) from color microscopic images based on a deep learning approach. The Convolutional Neural Network (CNN) based deep learning model was trained, validated and tested on a publicly available dataset composed of microscopic images of RBCs taken from individuals with confirmed malaria infection as well as normal control groups. Experimental results generated from the deep learning model showed that the detection capability of the model achieved 100% training accuracy, 96% validation accuracy and 96% testing accuracy. The developed App avails useful information about malaria disease in general and tips users with fundamental information regarding its prevention and transmission mechanisms acting as an m-health system.
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    A Video Coding Scheme Based on Bit Depth Enhancement With CNN
    (Addis Ababa University, 2023-06) Daniel Getachew; Bisrat Derebssa (PhD)
    Raw or uncompressed videos take a lot of resources in terms of storage and bandwidth. Video compression algorithms are used to reduce the size of a video and many of them have been proposed over the years. People also proposed video coding schemes which works on top of existing video compression algorithms by applying down sampling prior to encoding and restoring them to their original form after decoding for further bitrate reduction. Down sampling can be done in spatial resolution or bit depth. This paper presents a new video coding scheme that is based on bit depth down sampling before encoding and use CNN to restore it at the decoder. However unlike previous approaches the proposed approach exploits the temporal correlation which exists between consecutive frames of a video sequence by dividing the frames into key frames and non-key frames and only apply bit depth down sampling to the non-key frames. These non-key frames will be reconstructed using a CNN that takes the key frames and non-key frames as input at the decoder. Experimental results showed that the proposed bit depth enhancement CNN model improved the quality of the restored non-key frames by an average of 1.6dB PSNR than the previous approach before integrated to the video coding scheme. When integrated in the video coding scheme the proposed approach achieved better coding gain with an average of -18.7454% in Bjøntegaard Delta measurements.