Browsing by Author "Owusu-Ansah, Emmanuel"

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    A Proposed Method for Finding Initial Solutions to Transportation Problems
    (Pakistan Journal of Statistics and Operation Research, 2023) Owusu-Ansah, Emmanuel; Acheson, Valentine; Ackora-Prah, Joseph; Nkrumah, Seth K
    The Transportation Model (TM) in the application of Linear Programming (LP) is very useful in optimal distribution of goods. This paper focuses on finding Initial Basic Feasible Solutions (IBFS) to TMs hence, proposing a Demand- Based Allocation Method (DBAM) to solve the problem. This unprecedented proposal goes in contrast to the Cost- Based Resource Allocations (CBRA) associated with existing methods (including North-west Corner Rule, Least Cost Method and Vogel’s Approximation Method) which select decision variable before choosing demand and supply constraints. The proposed ‘DBAM’ on page 66 is implemented in MATLAB and has the ability to solve large-scale transportation problems to meet industrial needs. A sample of five (5) examples are presented to evaluate efficiency of the method. Initial Basic Feasible Solutions drawn from the study are of higher accuracy and will rapidly converge to optima in less iterations. The comparative results also showed that the DBAM outperforms other methods under this study which qualifies it as one of the best methods to solve industrial TMs.
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    A systematic framework for dynamic nodal vulnerability assessment of water distribution networks based on multilayer networks
    (Elsevier, 2021-11) Owusu-Ansah, Emmanuel; Tornyeviadzi, Hoese Michel; Mohammed, Hadi; Seidu, Razak
    Nodal demands vary throughout the day, as such any vulnerability analysis based on static networks, which considers daily average demands cannot realistically represent the criticality of nodes in the network. This study presents a systematic framework, which couples multilayer networks, structural reducibility and a Demand Adjusted Vulnerability Measure for dynamic nodal vulnerability assessment of water distribution networks (WDNs) under extended period simulation. Within this framework, we present the novel idea of characterizing the dynamics of WDNs with multi-slice networks, which captures the state of the network within a predefined temporal window taking into consideration the directional flow in pipes and the operational status of pumps, valves etc. Using a benchmark WDN, Net 3, as a case study we have demonstrated the importance of demand variations and operational status of various components, no matter how minuscule their operational time, on nodal vulnerability assessment in WDNs. The results indicated that the framework evaluates the criticality of all types of nodes, even intermediary nodes with zero base demand, within any temporal window much more realistically than conventional vulnerability analysis methods based on single (static) networks. Structural reducibility unearthed correlations between the operational status of source nodes and pumps on the general dynamics of the distribution system. The multilayer framework opens a new frontier in vulnerability analysis of WDNs and could serve as a tool for stakeholders in accessing node criticality, impact of various failure scenarios and optimal scheduling of maintenance routines.
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    A Two-Phase Method for Solving Transportation Models with Prohibited Routes
    (Pakistan Journal of Statistics and Operation Research, 2022) Owusu-Ansah, Emmanuel; Ackora-Prah, Joseph; Acheson, Valentine; Barnes, Benedict; Takyi, Ishmael
    The Transportation Problem (TP) is a mathematical optimization technique which regulates the flow of items along routes by adopting an optimum guiding principle to the total shipping cost. However, instances including road hazards, traffic regulations, road construction and unexpected floods sometimes arise in transportation to ban shipments via certain routes. In formulating the TPs, potential prohibited routes are assigned a large penalty cost, M; to prevent their presence in the model solution. The arbitrary usage of the big M as a remedy for this interdiction does not go well with a good solution. In this paper, a two-phase method is proposed to solve a TP with prohibited routes. The first phase is formulated as an All-Pairs Least Cost Problem (APLCP) which assigns respectively a non-discretionary penalty costM? ij M to each of n prohibited routes present using the Floyd’s method. At phase two, the new penalty values are substituted into the original problem respectively and the resulting model is solved using the transportation algorithm. The results show that, setting this modified penalty cost (M?) logically presents a good solution. Therefore, the discretionary usage of the M 1 is not a guarantee for good model solutions. The modified cost M? M so attained in the sample model, is relatively less than the Big M( 1) and gives a good solution which makes the method reliable.
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    ARTIFICIAL NEURAL NETWORK MODEL FOR LOW STRENGTH RC BEAM SHEAR CAPACITY
    (Journal of Science and Technology, 2012-08) Owusu-Ansah, Emmanuel; Afrifa, R. Owusu; Adom-Asamoah, M.
    This research was to investigate how the shear strength prediction of low strength reinforced concrete beams will improve under an ANN model. An existing database of 310 reinforced concrete beams without web reinforcement was divided into three sets of training, validation and testing. A total of 224 different architectural networks were tried, considering networks with one hidden layer as well as two hidden layers. Error measures of strength ratios were used to select the best ANN model which was then compared with 3 conventional design code equations in predicting the shear strength of 26 low strength RC beams. Even though the ANN was the most accurate, it was less conservative compared with the design code equations. A model reduction factor based on the characteristic strength concept is derived in this research and used to modify the ANN output. The modified ANN model is conservative in terms of safety and economy but not overly conservative as the conventional design equations. The procedure has been automated such that when new experimental sets are added to the database, the model can be updated and a new model could be developed.
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    Financing small-scale farmers in the Techiman District, Brong Ahafo Region of Ghana
    (1989) Owusu-Ansah, Emmanuel
    The desire for food self-sufficiency in C-ham has been a dream of all succeeding governments since independence. However, this dream has become an enigma, for a long time, as the country continues to rely on massive food importation and food aid to supplement her food requirements. One way of realising this dream of self-sufficiency in the country’s food needs is by increasing the productivity of the small-scale farmer. However, the growth andtdeve1opmen of the small-scale farmer is beset with many problems, most important of them being inadequate financing. Small-scale farmers in the Techiman District are no exception to this problem. The study, therefore, set out to analyse the characteristics of the financial constraints facing the small-scale farmers in the Techiman District and the reaction of the financial institutions in solving their financial problems. It was revealed from the study that most of the farmers are illiterates, use traditional implements, depend on rain-fed agriculture, have limited farm sizes and depend on family hands as farm labour. The characteristics of the existing sources of finance also revealed that the formal sources of finance play an insignificant role in financing small-scale farmers in the district not only because of their rigid lending procedures but also due to the poor repayment rate, diversion of loans from the purposes for which they were acquired, refusal to pay the loans and the dispersed nature of the small-scale farmers. These factors combine to make the banks very repulsive in granting loans to farmers. Informal sources such as money-lenders, personal savings, friends and relatives and cash advances from middlemen and traders, therefore, form the backbone for financing small-scale farmers. It was revealed that the informal sources are not only unreliable but also charge high interest rates which means that after repayment of the loan most farmers cannot have enough to meet their social expenditure and for further reinvestment in agriculture. It is against the background of the unreliability and. the high rate of interests of the informal sources that recommendations have been offered to help small-scale farmers get out of their financial problem. These recommendations include the need to increase extension services, formation of co-operative associations, fanner education, opening of more rural banks, the integration of formal and informal sources of finance and improvement in the marketing and distribution networks. It is hoped that these recommendations could help in solving the financial constraints, to the growth and development of small-scale farmers in the Techiman District and. other food producing areas in Ghana.
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    Hybrid Methods of Some Evolutionary Computations AndKalman Filter on Option Pricing
    (IJMER, 2017-07) Owusu-Ansah, Emmanuel; Ackora-Prah, Joseph; Osei, Pearl Asieduwaa
    The search for a better option price continues within the financial institution. In pricing a put option, holders of the underlying stock always want to make the best decision by maximizing profit. We present an optimal hybrid model among the following combinations: Kalman Filter-Genetic Programming(KF-GP), Kalman Filter-Evolutionary Strategy(KF-ES) and Evolutionary Strategy -Genetic Programming(ES- GP). Our results indicate that the hybrid method involving Kalman Filter-Evolutionary Strategy(KF-ES) is the best model for any investor. Sensitivity analysis was conducted on the model parameters to ascertain the rigidity of the model.
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    Parameter Estimation in Rainfall-Watertable Relationship Using Kalman Filter
    (Global Institute for Research and Education, 2013-01) Owusu-Ansah, Emmanuel; Ofori, E.,; Kyei-Baffour, N.,; Dontwi, I. K.; Atta-Darkwa, T.
    Employing a proper groundwater recharge estimation technique is extremely important for efficient water resource development in a groundwater basin. This paper describes the estimation of groundwater recharge in the Besease basin using the linear Kalman filter mathematical model. The physical model estimated the watertable levels and subsequently derived the infiltration parameters from rainfall inputs and groundwater levels data. The Kalman Filter method used as a recharge estimate resulted in a fit between the simulated hydraulic head and observed sub-surface water level fluctuation. The results show that the infiltration parameter varied considerably over the period of time when it was assumed as time dependent with the recharge values ranging between 0.0-1.27 % for P4 and 0.0-16.5 % for P14 of the incident rainfall. A very high infiltration factor α was obtained when considerable rain fell during June 2009, October 2009 and in June and July, 2010. However, during the periods from December 2009 to April 2010, the infiltration factor was zero which suggested that infiltrated water could not reach the water table but was retained in the unsaturated zone to replenish moisture deficit. Therefore, efficient application of irrigation water, knowledge about the moisture regime and the cropping pattern in the basin is fundamental for ensuring optimal moisture content and watertable level management.
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    Population, poverty and environmental degradation: the Ghanaian experience
    (2001) Owusu-Ansah, Emmanuel
    The rapid growth of the urban centres in the country, in terms of numbers and space, is creating a lot of environmental problems for the country. Firstly, natural resources in the form of forests, grass1ans, and even wetlands are now giving way to human settlements and infrastructural development. A second major environmental problem associated with urbanization in Ghana is the creation of waste products. The management of which has been the bane of the country. As a developing country, Ghana has been constrained financially in managing the domestic waste in the cities efficiently. The residents are also helpless in handling the waste since most of them do not have the financial resources to either use environmentally-benign facilities or to manage waste in efficient manner. The result of all these is mirrored in the fact that our surroundings are engulfed in the heaps of rubbish and even faeces. However, there have not been many quantitative analyses of this issue iii this country. In this dissertation, data on 150 heads of households from 4 communities in Accra and Kumasi have been used to investigate the relationship between population density and the levels of income of residents on one hand and the environmental pollution in such areas on the other. The findings of the study have confirmed the notion that population pressure and poverty are major agents of environmental pollution in the urban centres in Ghana. The target groups of the study are the residents of the urban centres of the country and the policymakers of such areas. It is intended that the residents would take a cue from the revelations of the study in terms of the health problems associated with environmental pollution. it is also hoped that the policymakers, especially the chief executives of the district assemblies, who are agents of developments would consider providing environmentally- friendly, public waste disposal facilities, especially at places being regarded as deprived areas
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    Power Theft Practices in Ghana: Key Perspective Indicators Undermining the Revenue Mobilization Among Some Selected Regions within NEDCo Operational Areas in Ghana
    (IJSB, 2022-09-02) Owusu-Ansah, Emmanuel; Appiah-Kubi, Baah; Amo-Boateng, Mark; Boamah, Bismark
    Power theft remains a challenge to electricity companies globally. Presently, despite the invention of new technologies to help combat it is also another difficult task because is not easy to detect and track. In Ghana, power theft practices have been estimated yearly to be one of the indicators that underrates the country’s economic growth. Therefore, the aim of this study was to investigate power theft practices: perspective keys undermining revenue mobilization in some selected NEDCo operational areas. This will help to determine power theft existence in those area understudy. A crosssectional study design was adopted where 4 regions (Bono, Bono-East, Savanna and Upper West were selected because they serve as the zones in which NEDCo operates. The study regions were stratified into 2 zones thus, middle belt and northern belt zones. 200 participants were recruited for the study based on the eligibility criteria with 100 questionnaires been administered to each of the zones in order to ascertain their views. The study showed that poor service delivery and lack of stringent measure compelled people to steal electricity. Power theft is practiced by all irrespective of location. The best way to reduce power theft practices is by vigorous hous eto house monitoring. More so, this calls for a greater urgency for research and development aimed at identifying proponent measures to mitigate power theft practices.
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    Substrate Ultilization for Bioremediation of Hydrocarbon Compounds
    (2012-06-20) Owusu-Ansah, Emmanuel
    We design, evaluate and compare the biodegradation performance of the application of compost (made up of some dead plants), Poultry manure (Organic) and inorganic chemical fertilizer (Urea) in the bioremediation of soil contaminated with petroleum hydrocarbon. Four different levels of nitrogen application were augmented for each of the substrates. A combination of treatments consisting of the application of poultry manure, Chemical fertilizer, and Compost was evaluated ex situ during a period of 8 weeks of remediation. The aim was to (i) find the best performance of substrate for the process, (ii) the level of nitrogen which stimulate performance (ii) find if there exists a significant difference in both the substrate and the level of nitrogen (iv) the best combination of substrate and level of nitrogen good for bioremediation process using ANOVA and Tukey’s test of difference. Contaminated soil containing oil and total petroleum hydrocarbon with different levels was bioremediated by blending of the hydrocarbon contaminated soil with portions of compost, poultry manure and fertilizer. After eight weeks of remediation, the most efficient contributor to hydrocarbon decomposition was poultry manure, followed by compost and fertilizer respectively. Moreover, in all the four (4) fixed nitrogen levels, it was found that, the higher the level of nitrogen the better the rate of degradation. For the substrate used, poultry manure-hydrocarbon blend recorded the least residual of Oil/ grease and TPH values followed by the compost substrate and with fertilizer blend recording the highest.