Computational Science

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Female Labor Force Status and Fertility in Akaki - a Sub-urban Industrial Town in Ethiopia
(Addis Ababa University, 1994-06) Gurmu, Eshetu; Hailemariam, Assefa (PhD)
This thesis focuses on the relationship between fertility and female labor force status in Akaki town. The study was based on a sample survey of 1475 eligible women belonging to the three female labor force status categories, namely, formal, informal and no work categories. Women were classified as eligible if they were aged 15-49, currently married, living with their first husband, fecund and had at least one live birth. The thesis discusses the sampling procedure employed and the quality of data; and examines the interrelationship between fertility and female labor force status using bi-variate and multi-variate statistical techniques of data analysis. Multiple classification analysis (MeA) and the log linear models were used in the multi-variate analyses. The Bongaarts model was also employed in order to show the interrelationship between female labor force status, fertility and some of the proximate variables. Fertility measured by children ever born was treated as the dependent variable and female labor force status (classified into formal, informal and no-work) was treated as the independent variable. Other variables such as age at first marriage, contraceptive use, duration of breast-feeding (in months), education, family type, childhood place of residence, husband's income and occupation were used as control. The findings indicate that fertility is inversely related to work of women in the formal labor force status category where as it is positively associated to work of women in the informal labor force status group. No definite relationship between female labor force status and fertility was observed in the case of women in the nowork category. Longer birth interval, higher contraceptive use, shorter duration of breast-feeding and lower desired family size were observed for women in the formal sector while for women in the informal sector, shorter birth interval, longer lactational period, lower contraceptive use and higher desired family size were observed. Results were not consistent for non-working women. Finally, the study concludes by suggesting some policy implications for intervention in areas of fertility and labor force participation as well as the need for detailed research in the same area.
Modeling Traffic Flow Problem: Comparison of Multilane Roundabout Versus Traffic Light Control
(Addis Ababa University, 2009-07) Yoseph, Dagim; Mitiku, Semu (PhD)
The vehicular traffic is controlled by a self-organized scheme in which traffic lights are absent at traffic junctions. This controlling method incorporates a yield-at-entry strategy for the vehicles approaching to the circulating traffic flow in the roundabout. Vehicular dynamics are simulated within the framework of the probabilistic cellular automata and the throughputs experienced at each individual street are evaluated for specified time intervals to determine the performance of the roundabout. We used Multi-stream Minimum Acceptable Space (MMAS) Cellular Automata (CA) model for the description of vehicular traffic at a roundabout. In this thesis inconsistency of driver behavior and interactions in cross traffic at entrances of roundabouts are simulated by incorporation of four different categories of driver behavior (i.e., conservative, moderate, urgent and radical). Our results give the critical throughput in which the intersection should be controlled in a self-organized manner is approximately 4500vph. This proves that below certain congestion, the roundabout efficiency is higher than fixed-time signalized junction point. In general, average throughputs for two-lane roundabout are lower than the signalized intersection, even for a fixedtime signalization.
Numerical Modelling of Thin Plates using the Finite Element Method
(Addis Abeba University, 2010-06) Gezahegn, Addisu; Zekaria, Adil (PhD)
In the advancement of digital computer it is becoming common to model a certain system to get a deep insight of the existing conditions. In this thesis Kirchoff's thin plate theory is considered to study static behaviour of a plate. Based on the assumption of the theory a finite element computer program is developed in FORTRAN using a linear triangular element. This thesis is mainly concerned in validating the numerical result obtained from the computer program. Hence the result is compared with analytical solution and with a general finite element program called Ansyis for a specific problem. Finally, recommendation is made on the selection of finiteelement meshes for future analyses
Seismicity of Afar and the Main Ethiopian Rift From 2000 - 2002 G.C.
(Addis Ababa University, 2011-06) Alemayehu, Sisay; Ayele, Atalay (PhD)
Earthquakes data recorded between 2000 and 2002 are used to study the seismicity of Ethiopia mainly focused around Afar and the Main Ethiopian rift. The locations of 238 local earthquake are determined using P- and S- wave arrival times recorded on three or more stations that resulted to a maximum of 1.5 root mean square (RMS). Previous studies of seismicity by Brazier et al., 2006 has been revisited using the same data from IRIS/PASSCAL broadband seismic experiments and adding more from ESSN (Ethiopian Seismic Station Network) sources. Comparing the results in this study with Brazier et al., 2006's, it is found that eight bogus events (earthquakes that didn't occur in the real world) and six more teleseismic earthquakes are reported as if they occurred in the Ethiopian neighborhood. On the other hand, it is observed that Brazier et al's work, which is published in Bulletins of Seismological Society of America (BSSA), reported 25 earthquakes that are located with readings from seismic stations less than three which puts doubt on the accuracy of the seismicity study. Another 53 new earthquakes are identi ed in the database and located in this study which has improved details of the seismicity of the region for the time period considered. A Fortran program is written in 0.5 by 0.5 degree window and with 0.5 degree sliding window in order to map the seismic energy release. The distribution of epicenter in this study shows high seismic activity around 90N and 40:500E; 9:500N and 39:500E during the study period, these epicenters are close to the N - S trending Ankober region, Kessem area and Dofen volcano. Coda magnitudes are also estimated for the reported events. Similarly b-values are estimated using both the least squares method and the maximum likelihood method. b-value of 0.9 0.09 and 1.10 were obtained using the maximum-likelihood method and using least square method determined respectively for the highly seismic Ankober-Dofen region during the study period. On the other hand, seismic energy map is developed for the whole region. The relatively high b-value estimated and the seismic energy mapping showed that seismic energy are released in the form of small magnitude.
Optimal Project Selection and Budget Allocation for the Selected Project
(Addis Ababa University, 2011-06) Taye, Nuhamin; Guta, Berhanu (PhD)
Project Selection is the process of evaluating individual projects, to choose the right project based on an analysis so that the objectives of the company will be achieved. It involves a thorough analysis including the most important nancial aspect to determine the most optimum project among all the alternatives. LINGO optimization tool has been adopted to determine the optimal project. The model presented in the paper shows a special tool for project selection based on in uences that govern the project selection process. Finally, an optimal budget is allocated to the selected project using a dynamic programming. The result showed that optimal project selection and optimal budget allocation should be used by organization to maximize their return.
Air Traffic schedule: the case of Bole International Airport.
(Addis Ababa University, 2011-06) Wetere, Thomas; Teklu, Tilahun (PhD)
This thesis is limited to the presentation of the single-server waiting line systems with Poisson arrivals and exponential service times. Waiting systems are stochastic mathematical models and they represent the describing base of the waiting phenomena, service processes and appropriate performance measures. The objective here is to describe the state of waiting line phenomena at Bole international airport and then improve its performance measurements. The data collected from Ethiopian civil aviation authority is then analyzed using mathematical models of queuing theory to determine performance characteristics of the Airport under steady state. Finally, solution results show that performance characteristics of Bole international Airport can be improved by either increasing the service rate or by adding new servers (runways) so that more aircrafts can be served simultaneously. Based on these results, recommendations are provided. Key words: Waiting line Models;queuing theory; waiting system; waiting line; Utilization rate; arrival rate; service rate;and queue discipline.
Knowledge Discovery From Satellite Images For Drought Monitoring
(Addis Ababa, 2013) Beman, Getachew; Alnafu, Solomon(PhD)
Drought is one of the most impo rtant challenges facing the planet. When it happens, it usually re sults in serious econom ic. environmental, and social cr ises. Despite the growi ng number of freely available biophysical, climate. and satellite data for characterizing and modeli ng drought, research efforts have been constrained to using only meteo rological point data, such as the amount of rainfall, for drought monitoring information. This po int data is insufficient for representing diversified ecosystems, and the data has coarse reso lut ion levels (lim ited spatial coverage). Researchers also have limited tools for data retrieval and integration for improved drought identification and model ing. which usua lly results in a time de lay fo r informat ion to reach dec is ion makers. Taking this into account, this dissertation researc h has three objectives: I) identify the most re levant attr ibutes for effic ient ly implementing drought monitoring, 2) develop a new approach for extracting knowledge from sate ll ite imageries for improved ident ifica tion and pred iction of drought, and 3) evaluate the new approach for national and regio nal dro ught prediction appl ications. Using an exploratory research approach and modeli ng research method, different data co llect ion and analys is techniques were executed using knowledge d iscovery in a database approach. The data mi ning models developed using art ificial neural network and regress ion tree models were able to predict DroughtObject with accuracy of 0.70 - 0.95 co rrelat ion coefficients. in a neta four month s' time lag. The develo ped DroughtObject model was evaluated for its application in showing drought severity and food defic it status. There were positive relat ionships between DroughtObjecl products and crop yield data up to 0.91 R2 values. The results confirmed that the model can direct ly be used by those who are currently responsible for drought monitoring and ri sk management. The new concept developed in this research was prolotypcd and demonstrated in an easy-tousc approach. with a focus on demonstfaling the concept of DroughtObjecl characterization and identification fro m a group of pixels. This demonSiration also revealed poss ible future system deve lopments. This di ssert ation research could he lp deci sion makers use advanced satellite technology fo r crrcctive drought monitoring and early warning systems in va rious regio ns. Combined with proper pol ic ies. Ihese systems can he lp to prevent famine and starvat ion in food-insecure reg ions. Up to now, satellite technologies have been used primarily in areas of meteoro logical applications. In this research. the main emphas is is on mining knowledge from satell ite images for dro ught ri sk assessment and sa ving the lives of individua ls who are affected by recurring drought s. The findings of this research can help decision makers take time ly and appropriate actions to save lives in drought-affected areas using advanced satellite techno logy.
Debt Collection Optimization: Commercial Bank of Ethiopia’s case
(Addis Ababa University, 2015-02) Girma, Benyam; Teklu, Tilahun (PhD)
This thesis develops and analyzes a finite horizon Markov decision process model for commercial bank of Ethiopia’s debt collection optimization problem. Two sectors namely domestic trade and services (DTS) and foreign trade (FT) have been studied primarily because of loan turnover rates and economic policy focus. A 2 years long data are used to determine cost of holding an outstanding loan in a certain state or delinquency status on a log scale where each state/status is scaled by the percentage of provision allocated to the states. Conclusions are made in terms of which loan segments banks need treat with more caution. Simple but important suggestions on ways of improving the operations of banks are made in the end.
Epidemiological Modeling of Measles Disease with Optimal Control of Vaccination Strategy
(Addis Ababa University, 2015-04) Zewdie Esayas; Oseloka Okey (Professor)
Epidemiological models provide a powerful tool for investigating the dynamics and control of infectious diseases, but quantifying the underlying epidemic structure can be challenging especially for new and under-studied diseases. Measles is a highly infectious disease which has a major impact on child survival, particularly in developing countries. The importance of understanding the epidemiology of this disease is underlined by its ability to change rapidly in the face of increasing immunization coverage with proper cost effectiveness. Much is still to be learned about its epidemiology and the best strategies for administering measles vaccines. However, it is clear that tremendous progress can be made in preventing death and disease from measles with existing knowledge about the disease, and by using the presently available vaccines and applying well-tried methods of treating cases. Since vaccination turned out to be the most effective strategy against childhood disease, developing a framework that would predict an optimal vaccine coverage level needed to control the spread of these diseases is crucial. We consider an optimal control problem subject to an SEIR measles epidemic model with vaccination controls. Our aim is find the best optimal control strategies to make the number of infectious individuals as small as possible and to keep the vaccination ratio of measles as low as possible during a certain vaccination period that will minimize the cost of control. We used Pontryagin’s maximum principle to characterize the optimal levels of the controls. The resulting optimality system is solved numerically by forward-backward sweep method. The results show that the optimal vaccination policy differs according to the controlled and uncontrolled individuals and has a very desirable effect upon the population for reducing the number of infected individuals. The effect of vaccination on transmission dynamics of measles is studied. The resulting optimality system also showed that, the use of vaccinating at the highest possible rate to the population as early as possible is essential for controlling an epidemic of the measles disease. Finally, we use our model to simulate the data of measles cases in the Ethiopia from 2004 to 2014 and design a control strategy (optimal vaccination policy) of the country to eliminate the epidemic for the future course with optimal control theory. The results from our simulation are discussed.
The Influence of Nonlinear Reaction, Memory and A Heaviside Function Source Term on Scalar Transport
(Addis Ababa University, 2016-06) Bekele Habtamu; Oseloka Okey (Professor)
In this study, a numerical method based on finite difference is presented for the numerical solution of a generalized Fisher-Integro differential equation. A composite weighted trapezoidal rule is manipulated to handle the numerical integrations which results in a closed difference scheme. The non-linear terms are linearized by one of the finite difference linearization techniques. Three different methods are used; Left end point rule, right end point rule and trapezoidal end point rule. The numerical solutions obtained for the three methods indicate that, the approach is reliable and yields results compatible. The discretization of the governing equation is made by explicit, Implicit and Crank-Nicolson method time scheme. The flow of an incompressible viscous fluid between a uniformly porous upper plate and a lower impermeable plate that is subjected to a FKPP is modeled and analyzed in this study. The Model equations are presented in terms of Left end point rule, Right end point rule and trapezoidal end point rule. For the Left end point rule, we are using the explicit method, for the right end point rule we are using the implicit method and for the trapezoidal end point rule we are using both implicit and explicit (Crank-Nicolson) method. In this study, the researcher looked how to discretize integro-partial differential equation (memory term) using trapezoidal, left endpoints, right endpoints and Simpson’s rule. The literature highlights how the Fisher Kolomogrov-Petrovskii-Piskunov Equation is developed and used. The main part of this paper is dedicated in discretizing FKPP and developing a computer program to compute the solution.
Screening food lesl pa.ramelers 10 deice I adulleration of leff (Eragroslis leI (Zucc.) Troller) flour and injera with non-edible adulteranls
(Addis Ababa University, 2017-06) Sileshi, Biruk; Geillch ew PhD, Paulos
Teff(Eragrostis fe/ (Zuee .) Troner) is the main staple cereal in Ethiopia that is used to prepare a fermented flatbread with a unique slightly spongy texture named injera. Majority of Ethiopian diets consist of injera which accounts for about two--th irds of the daily protein intake of the Ethiopian population. Recently, adulterat ion ofteffflour and injcra with non·cdible ingredients is becoming a serious problem puning the consumers' health at risk. Therefore, the main purpose of th is study is to screen some of the common food analyses test parameters that could detect nonedible adu lterants in lef[ flour and injera for potent ial use in future routi ne inspection ana lysis. In the study, simulation of the adulteration was made on two widely distributed white teffvarieti es, namely Quncho TefT (DZ-Cr-387) and Magna TefT (DZ-O 1-196). Three adulterants were selected based on the information gathered from local health bureau, namely Sawdust (organic adulterant) and two inorganic adu lterants, chalk powder (calcium carbonate) and gypsum (calcium sulphate dihydrate). Based on the information gathered, the lefT to adulterant ratio was (7:3). Thus, the primary investigation was conducted on this adulteration ratio. Accordingly, the analyt ical tests at this adulteration ratio resulted in a significant mean value difference between the adulterated and control teff nour samples. Secondary investigation was done by preparing injera using lower ratio ofteff nour to adulterants (9.5:0.5), (9: I), (8.5: 1.5), (8:2) and (7.5:2.5), while unadu lterated (100%) teO' nour injera was used as control. Ratios resulting in acceptab le injcra appearance were used as cut-off adulteration ratios to apply the selected test parameters. The final investigation was conducted using the cut-off adulteration ratio, on which the selected test parameters were applied to compare significant mean differences (p < 0.05) between control and adulterated tefTnour and injera samples. The overall results of the physicochemical analysis showed that some parameters like crude ash, and crude fib re, and mineral analysis of calcium could be used as detection test parameters for samples as low as 5% adulteration ratio. Qualitative tests such as effervescence and precipitation are also effective tests to detect adulteration. Therefore, this study provides test parameters for preliminary teIT flour and injera adulteration detection, which can further be developed by concerned bodies to come up with standard analytical procedu res for the detection leff and te IT injera with the tested and other simi lar adu lterants.
The Transmission Dynamics and Optimal Control of Hepatitis B in Ethiopia Using SVEIRS Model
(Addis Ababa University, 2017-10) Nurhasen Hindia; Oseloka Okey (Professor)
An epidemic model is a simplified means of describing the transmission of communicable disease through individuals. In this paper the mathematics behind the model and the various tools for judging effectiveness of policies and control methods on the spread of infectious diseases in populations has been analyzed mathematically. And it has been applied to specific diseases to study the propagation of diseases using the mathematical epidemic model. Epidemic models are many types form that select SVEIRS model and discussed the dynamics and control of infectious diseases, but quantifying the underlying epidemic structure can be challenging especially for new and understudied diseases. SVEIRS model is that generalizes several classical deterministic epidemic models then apply it for Hepatitis B. Consider compartments of susceptible, vaccination, exposed, infected, and recovered humans without immunity and modeled the natural growth, natural death and death due to disease and the interactions between these populations. The model has two equilibrium states namely, the disease - free and the endemic equilibrium points. The stability of each equilibrium point discussed has been found to be stable or unstable. The basic reproduction number(R0) estimate the stability, with (R0 > 1) whenever the transmission rate was increased or the recovery rate reduced but turned to the disease die out with (R0 < 1) whenever the transmission rate was reduced or the recovery rate increased. The results of our sensitivity analysis showed that the most sensitive parameter that controls the spread of Hepatitis B is the initial infection rate of the susceptible, b and d or death rate. Decreasing the value of b at the same rate as the other parameter values completely decreases the proportions of both the infective and the exposed more effectively than any parameter value. Consider an optimal control problem subject to an SVEIRS Hepatitis B epidemic model with vaccination controls. Our aim is to find the best optimal control strategies to make the number of infectious individuals as small as possible and to keep the vaccination ratio of Hepatitis B as low as possible during a certain vaccination period that will minimize the cost of control. Pontryagin’s maximum principle to characterize the optimal levels of the controls. The resulting optimality system is solved numerically by forward-backward sweep method. The results show that the optimal vaccination, drug and education using media differs according to the controlled and uncontrolled individuals and has a very desirable effect upon the population for reducing the number of infected individuals. The effect of vaccination on transmission dynamics of Hepatitis B is studied. The resulting optimality system also showed that, the use of vaccinating at the highest possible rate to the population as early as possible is essential for controlling an epidemic of the Hepatitis B disease. Finally model to simulate the data of Hepatitis B cases in the Ethiopia from 2015 and design a control strategy of the country to eliminate the epidemic for the future course with optimal control theory. Keywords: SVEIRS-Model; mathematical models; vital dynamics; vaccinations; HB, HBV, Herd Immunity; epidemiology number, optimal control.
Systematic Global Optimization Algorithm for a General Multilevel Multi Follower Stackelberg Nash Problems with Bounded Decision Range
(Addis Ababa University, 2018-06-12) Dagne, Yonas; Goa, Mengistu
Today, many decision makers decide a decision which is hard to accept and could affect or leave to unpleasant situation to those who follows them in structural arrangements. This is because of challenge of solving Structural multi level interdependent set of objects. And most of computational model has challenge for finding the optimal result of each object that considerer all the constraints and limitations of each decision maker in both computational time and decision support quality. This thesis develops a computational optimization computerized model based on root finding technique for a bounded decision range in a non-cooperative environment to reduce computational time and improve decision support quality.
Effectiveness of selling fruits in pieces or in bulk in improving fruit consumption of high-school students: A cluster randomized controlled trial in urban setting of Ethiopia
(Addis Ababa University, 2019-10) Gebremichael, Bereket; Baye PhD, Kaleab
Background: Diets high in fnlits and vegetables arc widely recommended for hcahhicr life. Fruits have historically he ld a place in dietary guida nce because of their concentrations of dietary fib er, vitamins, minerals, electrolytes; and morc recently phytochcmicals, especially antioxidants. However, fruit consumption in Ethiopia is very low. The barriers and enablers affecting consumer behavior towards fruits consumption including price, preference, qual ity, safety and access are largely undocumented; hence, maki ng it diffi cult to design effective interventions that improve consumption of fruit s. For example, fnlils arc sold around some schools, but the minimum amount that one can buy is half a ki logram, This may discourage students from buying fru its as a snack and may contribute to the purchase of sweets and biscuits that arc more affordable to thcm. Objective: The objective of this study was to evaluatc whet her selling fmits in pieces improves consumption and volume of sale than the current practice of selling fruits in bulk (kilogram). Methodology: A cluster randomized contfolled trial was conducted from April through June 20 19 in selected schools of Addis Ababa, Ethiopia. A double population proportion for cluster randomized trial was employed to calcu late thc sample size. After adding 5% non-response rate, the lolal smnple size was estimated to be 369. Data were collected on socio-demographic infomlation, fruit consumption pattem, vo lumc of sale per day and other variable that determine fruit consumption pattem by usi ng semi structured and pre tested tool. EPI data version 4.2.0 was used to code, enter and clean the collected data. Data WCfe analyzed usi ng SPSS version 20 and SAS version 9.4. Descriptive statistics were lIsed to describe variables in relation to thc outcome. Mixed-effect linear regress ion was employed to see the impact of intcrvention. We lIsed unstructured variance matrix stnteture to estimate the parameters of the random intercept. All tests were two-sided and P<0.05 was considered stati stically significant. We report Ihe parameter estimates with 95% CI and standard errors (SE). Result: Out of 157 partic ipants in the intervention group 80 (51 %) and 77 (5 1 %) were male and female respectively. In the control group, 65(37.6%) and 108 (62.4%) were male and female respectively. The mean (SO) age of intervention and control group was 15.9 ( 1.2) and 17 (1.06) respectively. With regards 10 a one-week recall fruit consumption, Banana consumption was 82% in the intervention group when compared with 65% of control (P <0.001), Water melon and mango consumption was also higher in intervention group with proportion of 12.7% and 61.1 % in comparison wi th 4% and 44.5% (P
Level of Aflatoxin in Dairy Feed, Poultry Feeds and Feed Ingredients Produced by Feed Factories in Addis Ababa, Ethiopia
(Addis Ababa University, 2019-10) Mengesha, Genet; Bekele Assistant Prof., Tilahun
Aflatoxins arc one of the major faclors thai affect the quality and safety of feeds that arc transferred into li vestock species and then to humans via animal sources of food (meal, egg and mi lk). The objective of this study was to detect and quantify the level of aflatox ins (8 I, 82, G I, G2 and total aflatoxin) in dairy feed, poultry (layer tInd broiler) feed and feed ingredients produced in feed factories in Addis Ababa also 10 evaluate knowledge Attitude and Practice (KAP) of feed producers and farmers in regard to feed qua lity and safety. A total of 42 samples consisting of five dairy feed s, six poultry broiler feed s, six layer feeds and 25 feed ingredients were collected from seven dairy and poultry feed factories found in Addis Ababa and ils surroundings. Samples were analY.led using High Performance Liquid Chromalography after cleaned up with lmmunoaffinilY columns. The eva lualion of KAP was done using a slruclured questionnaire. In the feed samples analY.lcd, the aflatoxin B I levels obtained ranged from (5 1.66 to 370.51) ).Lglkg in dairy cattle feed; from ( 1,45 to 139.5 1) ).Lglkg in poultry layer feed; and from ( 16.49 to 148.86) ).Lglkg in broi lcr feed. In feed ingredients on the other band, afl atoxin B I levels ranged from (2.64 to 46.74) J.1g1kg in maize grain; from Not Detectcd (ND) to 3.66 J.1g1kg in wheat bran; from NO to 12.77 J.1g1kg in whcat middl ing; from D to 3.43J.1g!kg in soybean; and from (110.93 to 438.86) J.1g!kg in nigcr seed cake. 100% of dairy fced s, 67% of poultry laycr, 67% broi ler feeds and 24% of ingredients con tained aflatox in in levels higher than the maximum tolerable lim it set by the US Food and Drug Adminimation and Eth iopian Standard Agency. The result of KAP assessmcnt revcaled that only 63% of fced producers and fanners had awarencss about the formation of aflatox ins in fccds. In conclusion, dairy feed from feed types and nigcr seed cake from feed ingredients were the most heavily contaminated with aflatoxi ns that need better feed managcment by the producers and strong regulation by the government. There should be regular monitoring of aflatoxin in animal feeds by the feed manufactures to prevent aflatoxin buildup in dairy feeds, poultry feeds, and feed ingredients to ensure the health of an imals and sa fe ty of animal source of foods like mi lk, egg and meat.
Numerical and Nonlinear Dynamical Systems Analysis for Fluid Mechanics and Heat Transfer Problems
(Addis Ababa University, 2020-07-16) Alemseged, Nahom; Oseloka, Okey (professor)
In This Thesis, Different Heat Transfer And Boundary Layer Flow Problems Coupled With Heat Transfer, Thermodynamics And Electromagnetism Has Been Studied. Problems Concerning Heat Transfer In Fins And Thermal Explosion End Up In A Second Order Nonlinear Odes, Which Are Then Solved Using Numerical Method, Specifically The Shooting Secant Method. Dynamical Systems Analysis Is Also Studied For These Problems. Boundary Layer Flow Coupled With Heat Transfer, Thermodynamics And Electromagnetism, And Nano Fluid Flow Is Also Studied In This Thesis. They End Up In Highly Nonlinear Coupled Odes, Which Are Then Solved Using Numerical Method (Shooting Secant). Background Of The Specific Problem Introduced In The Chapter, Together With The Mathematical Formulations Of Ythe Problem And Descriptions Of The Results Are Then Provided. The Description Based On The Physics Of The Problems Are Discussed In Detail For Each Chapters.
Epidemiological Study and Comments on two Highly Contagious Diseases in Africa
(Addis Ababa University, 2020-09-09) Gebremedhin Addis; Oseloka Okey (Professor)
Epidemiological studies and comment on two highly contagious disease Ebola and Coronavirus Outbreak from the bases of Computational Science program and Epidemiological models considering Susceptible, Infected, Recovered, Vaccine, Quarantine and Death etc. trying to illustrate the activity of Ebola and Coronavirus disease Outbreak in many ways like figurative ways in different compartement which illustrate detail from Supceptible to Infected from infected to Recover stage and from infected to quarantine stage or death etc. And from that observation asesement method computitional by which I learnt in Computational science departement by appling mathimatical model using Ordinary differential equation,these equations model the dynamics of the transitions from the mathimatical model SIR,SIRD,SIRV,SIQR, and Algorithem, using Matlab codeing and plot. I learnt and recogized how the disease moves and behaves from one Compartement to another compartement and how it incline and decline of each activity on the figuer. By certain mathimatical model, by using algorthim by setting Matlab code and by plotting graphs through Matlab program, I tried to show how the cases of the Virus it behaves from one stage to another stage how it increases,decrease and recover from supceptable stage to infected stage and recoverd or quarntine (death) stage. The progress between these sections could be presented as formal mathimatical terms to make quantitative predictions and interpolation,we can translate them into formal mathematical terms. This paper illustrate the stage of the diseases, the level of the diseases and describes by using mathematical models by using collective data in Table, Tabular form by ploting graphs to illustrates these models together with the kinds of mathimatical model analyses that have proved which is useful to epidemiologists. West Africa Ebola disease outbreaks from 2013-2019 and Coronavirus 2019-2020 has brought to light the significance of epidemic modeling and pandemic modeling at a time considered when many serious illnesses are no longer a threat to Public Health. Between regions and continents Countries the increasing connectivity makes it to understand the mechanisms that drive the spread of new acute illnesses and our ability to control them at the source more important now than ever before. In general Epidemiology of the Ebola and Coronavirus in particular it is a disease, poorly understood, and capable of causing threat to Public Health and corona virus disease is considered analyzed statistically and model using the SIR,SIRD,SIRV, and SIQR model. Differential equation formulated the non-linear systems of solving numerically using MS-Excel and Mat-lab program over time period of 120 days. For simplicity, Democratic Republic of Congo, Liberia, Guinea West African Countries that was hit severely by EVD in 2014 was used for this study. As stated earlier, modeling infectious disease dynamics demands that we investigate whether the disease spread could accomplish an epidemic level or pandemic it could be wiped out. The Ebola and covid-19 Virus is spread largely through contacts between an infected person and a non-infected person. Infected people cannot be entirely separated or quarantined from the rest of the large population in the case of Ebola but in the case of Covid-19 entirely we separate and isolate the infected person from the people. In the case of Ebola the separation can only be done when an infected person visits a health center but in the case of Corona virus we trace and isolate or separate them from the beginning we identify the person who is positive.
Application of Newton and Quasi-Newton Techniques to Non-Linear Problems in Computational Mechanics
(Addis Ababa University, 2020-11-12) Habtamu, Fikru; Oseloka, Okey (Professor)
In the field of engineering, researches often come across strong nonlinear boundary value problems (BVPs) that cannot solve easily. Numerical convergence for many problems, typically solved by the Newton-Raphson algorithm, is sensitive to the initial guess and need computations of Jacobi and its inverse at each iteration. Emphasis in the present work is placed on the alternative approach, such as quasi-Newton, HM and optimization method. Many problems in applied mechanics are reduced to the solutions of systems of nonlinear algebraic, transcendental equations containing an explicit parameter. These are problems in the areas of thermo-fluids, gas dynamics, deformable solids, heat transfer, biomechanics, optimal control and others. A parameter found in these models is not unique, and may be easily identified artificially. An important aspect of these problems is a question of the variation of the solution when parameter is incrementally changed. The numerical solution of BVPs of ordinary differential equations (ODE‟s) relies heavily on methods for solving systems of algebraic equations. The choice of the optimal numerical method, which ensures the best convergence rate with minimum error for the corresponding system of nonlinear equations, is discussed. Some modifications of quasi-Newton‟s method for systems of ordinary nonlinear differential equations are apply and suggested. Effectiveness of the method is demonstrated by comparing the results with the analytic solution for model boundary value problem implemented using a MATLAB Program. The objective of the research is to investigate applicability of the method to the wide range of nonlinear boundary value problems in different areas of mechanics. Different problems of applied mechanics and physics with dominant nonlinearities due to constituent models, and others are analyzed and solve in the present work. In this paper, the Newton‟s Homotopy analysis method (NHAM) is also applied on nonlinear boundary value problems(BVPs) of mechanics problems. The result from the method prove NHAM with Runge-Kutta steps, were significantly reliable and more accurate however, computation cost is high.
Block-skill Framework for a Mutable Blockchain-based Data: In Case of a Job-driven Education System
(Addis Ababa University, 2021-03-06) Berhane, Henok; Libsie, Mulugeta (PhD)
Blockchain is a list of records called blocks that collectively and sequentially stores information and that cannot be changed or deleted. However, in the context of the current conditions, the question of making modifications and deleting data in blockchain has recently been asked. Besides, this is again contrary to applications that need modifying storage. Numerous research efforts and methods have been proposed to address this limitation, but they are still being made to balance the limitations with other needs. For this reason, we proposed a Mutable blockchain-based data operation with Block-skill framework. Block-skill is a Blockchain-based framework, in which blocks are used to store information using hash functions and it uses smart contracts to achieve the mutability of blockchain data and to fulfill the role and functions of applications that use the framework. As a result, the use of Block-skill Framework in case of job-driven education system started with studying the state of the art of the system using survey research design technique. The participants of the survey were 15 Businesses, 15 Employees, 8 Higher learning institutions, and 7 Recruiting agents, which are selected through Purposive and Convenience sampling techniques. Therefore, both quantitative and qualitative data were collected and analyzed. Our analysis of the survey data indicates the roles and activities of the participants, key points about skill gaps and the need for secure stakeholder collaboration. Consequently, in response to the importance of mutable blockchain that follows the practices of a job-driven education system, Block-skill Framework is found to be a promising solution. The feasibility of the Block-skill Framework has been validated in the mutability of Blockchain data for multiple peers executing on the same on-chain data. This is as a result of the integrity maintaining function on the developed smart contracts to retain the original as well as the modified versions of data. Besides, Blockchain data is classified into off-chain and on-chain and its hash information is stored in the blockchain to control references to off-chain information. A prototype is developed for the implemented framework and a usage scenario is evaluated using questionnaires. The prototype evaluation result confirmed the viability of the framework as well as the assured integrity using the smart contracts.
Computational Modeling and Analysis of Traffic Crash and Traffic Volume in Addis – Adama Expressway
(Addis Ababa University, 2021-04-26) Murad, Ayana; Gizaw, Solomon (PhD)
Transportation has a major contribution in the development of the human civilization. The accessibility of highway transportation has given many focal points that contribute to a high standard of living. However, many issues related to the highway mode of transportation exist. These issues incorporate highway related accidents, parking troubles, clog, natural risks (carbon emissions, clamor contamination, etc.) and delay. To solve these problems building expressways is one of the solutions. Even though building express way is a good solution for solving problems related to highway traffic, Data collected from Ethiopia Toll Road Enterprise indicated that, on average, about 417 road crashes were reported since September 2014 to February 2016 that leads around 672 traffic accidents. Road traffic crashes (RTCs) are globally acknowledged as increasing threat to society, because they can affect many lives when they result in severe injury or fatality. Ethiopia is among the leading countries in road traffic accident. The recent road safety record of Addis Ababa- Adama expressway is also alarming the severity of the situation and calling for an integral effort of all pertinent stakeholders to reverse the trend. In this research we modeled traffic crashes and traffic volumes in Addis – Adama express way with ordinary differential equation using interpolation methods (i.e. newton DVD and Lagrange interpolations). We solved the ordinary differential equations we got after modeling using Euler method and Runge – Kutta method. We observed if there is any relation between traffic crash and traffic volume. We analyzed the traffic crash data parameters i.e. vehicle type, vehicle type with weekdays and direction to observe the factors causing traffic accident. The data we used for modelling and analyzing is collected from ETRE. Using the mathematical model of traffic crash, we were able to predict 2020 number of traffic crash. The finding shows that traffic crash and traffic volume have linear relationship. From the analysis we observed that Small automobiles are causing the highest traffic crash, the highest number of traffic crash occurred in Friday, and vehicles heading to mojo are causing the highest number of traffic crash. Therefore, ETRE should take restrict monitoring on small automobiles, vehicles heading to mojo, and in weekends.

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