Tawiah Quartey-Papafio | Nanjing University of Aeronautics and Astronautics (original) (raw)

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Research paper thumbnail of Forecasting cocoa production of six major producers through ARIMA and grey models

Grey Systems: Theory and Application, 2020

PurposeIn the current study, two grey prediction models, Even GM (1, 1) and Non-homogeneous discr... more PurposeIn the current study, two grey prediction models, Even GM (1, 1) and Non-homogeneous discrete grey model (NDGM), and ARIMA models are deployed to forecast cocoa bean production of the six major cocoa-producing countries. Furthermore, relying on Relative Growth Rate (RGR) and Doubling Time (Dt), production growth is analyzed.Design/methodology/approachThe secondary data were extracted from the United Nations Food and Agricultural Organization (FAO) database. Grey forecasting models are applied using the data covering 2008 to 2017 as their performance on the small sample size is well-recognized. The models' performance was estimated through MAPE, MAE and RMSE.FindingsResults show the two grey models fell below 10% of MAPE confirming their high accuracy and forecasting performance against that of the ARIMA. Therefore, the suitability of grey models for the cocoa production forecast is established. Findings also revealed that cocoa production in Côte d'Ivoire, Cameroon, G...

Research paper thumbnail of Grey relational evaluation of impact and control of malaria in Sub-Saharan Africa

Grey Systems: Theory and Application, 2019

Purpose The rise in malaria deaths discloses a decline of global malaria eradication that shows t... more Purpose The rise in malaria deaths discloses a decline of global malaria eradication that shows that control measures and fund distribution have missed its right of way. Therefore, the purpose of this paper is to study and evaluate the impact and control of malaria on the independent states of the Sub-Saharan African (SSA) region over the time period of 2010–2017 using Deng’s Grey incidence analysis, absolute degree GIA and second synthetic degree GIA model. Design/methodology/approach The purposive data sampling is a secondary data from World Developmental Indicators indicating the incidence of new malaria cases (per 1,000 population at risk) for 45 independent states in SSA. GIA models were applied on array sequences into a single relational grade for ranking to be obtained and analyzed to evaluate trend over a predicted period. Findings Grey relational analysis classifies West Africa as the highly infectious region of malaria incidence having Burkina Faso, Sierra Leone, Ghana, Be...

Research paper thumbnail of Critical Factors in Process Quality of Engineering Construction Projects during Building Design Phase

International Journal of Grey Systems

Quality in construction is an important topic in the design phase due to the quick change in tech... more Quality in construction is an important topic in the design phase due to the quick change in technological advancement. The current study focuses on the identification, measurement, and analysis of the critical elements which impact the process quality of building construction projects during the design stage in Pakistan. Elements were graded using the conservative Relative Importance Index (RII) and Grey Absolute Decision Analysis (GADA). The findings indicate that during the design phase, the critical element impacting process quality is the quality of codes and standards and was facilitated using a questionnaire survey. Similarly, the teamwork of parties in design firms and constructability analysis of the design are key factors during the design phase in Pakistan. Measures for the improvement of process quality in Pakistan were suggested. The building construction projects need to be modified to cover the important aspects of constructability analysis, continuous working on trai...

Research paper thumbnail of Mathematical modeling for optimizing the blood supply chain network

Modern Supply Chain Research and Applications

PurposeThis research studies a location-allocation problem considering the m/m/m/k queue model in... more PurposeThis research studies a location-allocation problem considering the m/m/m/k queue model in the blood supply chain network. This supply chain includes three levels of suppliers or donors, main blood centers (laboratories for separation, storage and distribution centers) and demand centers (hospitals and private clinics). Moreover, the proposed model is a multi-objective model including minimizing the total cost of the blood supply chain (the cost of unmet demand and inventory spoilage, the cost of transport between collection centers and the main centers of blood), minimizing the waiting time of donors in blood donating mobile centers, and minimizing the establishment of mobile centers in potential places.Design/methodology/approachSince the problem is multi-objective and NP-Hard, the heuristic algorithm NSGA-II is proposed for Pareto solutions and then the estimation of the parameters of the algorithm is described using the design of experiments. According to the review of th...

Research paper thumbnail of Evaluating Suppliers for Healthcare Centre using Ordinal Priority Approach

Management Science and Business Decisions

Supplier selection is one of the most critical problems in the industry. In the healthcare sector... more Supplier selection is one of the most critical problems in the industry. In the healthcare sector, where the tolerance level for mistakes and errors is low, the need to improve the supplier evaluation system is ever increasing. Earlier, the cardinal data-based mathematical models played an important role in supplier selection however since last few decades, the emphasis on the decision-making methods that can handle ordinal relations is gaining exceeding attention. The development of the Ordinal Priority Approach (OPA) is an essential milestone in this regard that is being used in the current study to evaluate the suppliers of a Chinese healthcare facility. The study confirms that the OPA is convenient and powerful approach that can single-handedly estimate the weights of suppliers, criteria and experts. The results demonstrated the feasibility and validity of the approach for healthcare supplier selection problems.

Research paper thumbnail of Grey relational evaluation of impact and control of malaria in Sub-Saharan Africa

Emerald Grey Systems: Theory and Application, 2019

Purpose-The rise in malaria deaths discloses a decline of global malaria eradication that shows t... more Purpose-The rise in malaria deaths discloses a decline of global malaria eradication that shows that control measures and fund distribution have missed its right of way. Therefore, the purpose of this paper is to study and evaluate the impact and control of malaria on the independent states of the Sub-Saharan African (SSA) region over the time period of 2010-2017 using Deng's Grey incidence analysis, absolute degree GIA and second synthetic degree GIA model. Design/methodology/approach-The purposive data sampling is a secondary data from World Developmental Indicators indicating the incidence of new malaria cases (per 1,000 population at risk) for 45 independent states in SSA. GIA models were applied on array sequences into a single relational grade for ranking to be obtained and analyzed to evaluate trend over a predicted period. Findings-Grey relational analysis classifies West Africa as the highly infectious region of malaria incidence having Burkina Faso, Sierra Leone, Ghana, Benin, Liberia and Gambia suffering severely. Also, results indicate Southern Africa to be the least of all affected in the African belt that includes Eswatini, Namibia, Botswana, South Africa and Mozambique. But, predictions revealed that the infection rate is expected to fall in West Africa, whereas the least vulnerable countries will experience a rise in malaria incidence through to the next ten years. Therefore, this study draws the attention of all stakeholders and interest groups to adopt effective policies to fight malaria. Originality/value-The study is a pioneer to unravel the most vulnerable countries in the SSA region as far as the incidence of new malaria cases is a concern through the use of second synthetic GIA model. The outcome of the study is substantial to direct research funds to control and eliminate malaria.

Research paper thumbnail of Forecasting cocoa production of six major producers through ARIMA and grey models

Grey Systems: Theory and Application, 2020

PurposeIn the current study, two grey prediction models, Even GM (1, 1) and Non-homogeneous discr... more PurposeIn the current study, two grey prediction models, Even GM (1, 1) and Non-homogeneous discrete grey model (NDGM), and ARIMA models are deployed to forecast cocoa bean production of the six major cocoa-producing countries. Furthermore, relying on Relative Growth Rate (RGR) and Doubling Time (Dt), production growth is analyzed.Design/methodology/approachThe secondary data were extracted from the United Nations Food and Agricultural Organization (FAO) database. Grey forecasting models are applied using the data covering 2008 to 2017 as their performance on the small sample size is well-recognized. The models' performance was estimated through MAPE, MAE and RMSE.FindingsResults show the two grey models fell below 10% of MAPE confirming their high accuracy and forecasting performance against that of the ARIMA. Therefore, the suitability of grey models for the cocoa production forecast is established. Findings also revealed that cocoa production in Côte d'Ivoire, Cameroon, G...

Research paper thumbnail of Grey relational evaluation of impact and control of malaria in Sub-Saharan Africa

Grey Systems: Theory and Application, 2019

Purpose The rise in malaria deaths discloses a decline of global malaria eradication that shows t... more Purpose The rise in malaria deaths discloses a decline of global malaria eradication that shows that control measures and fund distribution have missed its right of way. Therefore, the purpose of this paper is to study and evaluate the impact and control of malaria on the independent states of the Sub-Saharan African (SSA) region over the time period of 2010–2017 using Deng’s Grey incidence analysis, absolute degree GIA and second synthetic degree GIA model. Design/methodology/approach The purposive data sampling is a secondary data from World Developmental Indicators indicating the incidence of new malaria cases (per 1,000 population at risk) for 45 independent states in SSA. GIA models were applied on array sequences into a single relational grade for ranking to be obtained and analyzed to evaluate trend over a predicted period. Findings Grey relational analysis classifies West Africa as the highly infectious region of malaria incidence having Burkina Faso, Sierra Leone, Ghana, Be...

Research paper thumbnail of Critical Factors in Process Quality of Engineering Construction Projects during Building Design Phase

International Journal of Grey Systems

Quality in construction is an important topic in the design phase due to the quick change in tech... more Quality in construction is an important topic in the design phase due to the quick change in technological advancement. The current study focuses on the identification, measurement, and analysis of the critical elements which impact the process quality of building construction projects during the design stage in Pakistan. Elements were graded using the conservative Relative Importance Index (RII) and Grey Absolute Decision Analysis (GADA). The findings indicate that during the design phase, the critical element impacting process quality is the quality of codes and standards and was facilitated using a questionnaire survey. Similarly, the teamwork of parties in design firms and constructability analysis of the design are key factors during the design phase in Pakistan. Measures for the improvement of process quality in Pakistan were suggested. The building construction projects need to be modified to cover the important aspects of constructability analysis, continuous working on trai...

Research paper thumbnail of Mathematical modeling for optimizing the blood supply chain network

Modern Supply Chain Research and Applications

PurposeThis research studies a location-allocation problem considering the m/m/m/k queue model in... more PurposeThis research studies a location-allocation problem considering the m/m/m/k queue model in the blood supply chain network. This supply chain includes three levels of suppliers or donors, main blood centers (laboratories for separation, storage and distribution centers) and demand centers (hospitals and private clinics). Moreover, the proposed model is a multi-objective model including minimizing the total cost of the blood supply chain (the cost of unmet demand and inventory spoilage, the cost of transport between collection centers and the main centers of blood), minimizing the waiting time of donors in blood donating mobile centers, and minimizing the establishment of mobile centers in potential places.Design/methodology/approachSince the problem is multi-objective and NP-Hard, the heuristic algorithm NSGA-II is proposed for Pareto solutions and then the estimation of the parameters of the algorithm is described using the design of experiments. According to the review of th...

Research paper thumbnail of Evaluating Suppliers for Healthcare Centre using Ordinal Priority Approach

Management Science and Business Decisions

Supplier selection is one of the most critical problems in the industry. In the healthcare sector... more Supplier selection is one of the most critical problems in the industry. In the healthcare sector, where the tolerance level for mistakes and errors is low, the need to improve the supplier evaluation system is ever increasing. Earlier, the cardinal data-based mathematical models played an important role in supplier selection however since last few decades, the emphasis on the decision-making methods that can handle ordinal relations is gaining exceeding attention. The development of the Ordinal Priority Approach (OPA) is an essential milestone in this regard that is being used in the current study to evaluate the suppliers of a Chinese healthcare facility. The study confirms that the OPA is convenient and powerful approach that can single-handedly estimate the weights of suppliers, criteria and experts. The results demonstrated the feasibility and validity of the approach for healthcare supplier selection problems.

Research paper thumbnail of Grey relational evaluation of impact and control of malaria in Sub-Saharan Africa

Emerald Grey Systems: Theory and Application, 2019

Purpose-The rise in malaria deaths discloses a decline of global malaria eradication that shows t... more Purpose-The rise in malaria deaths discloses a decline of global malaria eradication that shows that control measures and fund distribution have missed its right of way. Therefore, the purpose of this paper is to study and evaluate the impact and control of malaria on the independent states of the Sub-Saharan African (SSA) region over the time period of 2010-2017 using Deng's Grey incidence analysis, absolute degree GIA and second synthetic degree GIA model. Design/methodology/approach-The purposive data sampling is a secondary data from World Developmental Indicators indicating the incidence of new malaria cases (per 1,000 population at risk) for 45 independent states in SSA. GIA models were applied on array sequences into a single relational grade for ranking to be obtained and analyzed to evaluate trend over a predicted period. Findings-Grey relational analysis classifies West Africa as the highly infectious region of malaria incidence having Burkina Faso, Sierra Leone, Ghana, Benin, Liberia and Gambia suffering severely. Also, results indicate Southern Africa to be the least of all affected in the African belt that includes Eswatini, Namibia, Botswana, South Africa and Mozambique. But, predictions revealed that the infection rate is expected to fall in West Africa, whereas the least vulnerable countries will experience a rise in malaria incidence through to the next ten years. Therefore, this study draws the attention of all stakeholders and interest groups to adopt effective policies to fight malaria. Originality/value-The study is a pioneer to unravel the most vulnerable countries in the SSA region as far as the incidence of new malaria cases is a concern through the use of second synthetic GIA model. The outcome of the study is substantial to direct research funds to control and eliminate malaria.