Yohannes Yebabe Tesfay

Modeling the Causes of the Bullwhip Effect and Its Implications on the Theory of Organizational Coordination

This article analyzes the potential cause of bullwhip effect using experimentally simulated data from a beer distribution game. The game represents a simple supply chain that consists of a factory, distributor, wholesaler, and retailer. The study used the bootstrapping estimation technique on ANOVA models, signal processing, and recessive autoregression estimation methods, which resulted in preliminary findings that confirmed that the bullwhip effect has different cost implications to various business partners in the supply chain. The inventory cost is higher in the upstream of the supply chain. Consequently, the stock-out cost is higher in the downstream of the supply chain. The generalization of the preliminary findings suggests that one way or another, the bullwhip effect attacks all business partners in the supply chain. Then, we tried to analyze the causes of the bullwhip effect. The Cochrane-Orcutt autoregression recursive estimation result showed that the bullwhip effect can be caused by intra- and inter-organizational coordination of the business partners in the supply chain. The effect of the intra-organizational coordination on the bullwhip effect showed the drawback of existing theory on organizational coordination. The analysis showed that in order to make the supply chain more efficient and effective a coordination type, named hyper-hybrid coordination, is introduced, which helps us to modify the Kraljic portfolio model. Finally, we have shown some applications of the hyper-hybrid coordination in the supply chain of agricultural products.

Derivation of econometric estimable functions of intra-trade industry: the case of the Norwegian intra-continental import trade pattern

This paper evaluates the item-based Norwegian intra-continental trade pattern. The paper derives the best linear unbiased estimator (BLUE) of estimable functions of the two-stage non-full rank hierarchical linear econometric model for the analysis of the intra-continental variations of the yearly Norwegian import expenditures for the period 1988-2014. The result confirms that the intra-Europe, item-based trade pattern of the Norwegian import trade is characterised as very stable, standardised and predictable. However, most of the items of import from the other continents show lack of stability and predictability. The result implies that efforts by governments (or firms) for trade stability have little effects.

Intercontinental variations of the import trade pattern of Norway: applications to best linear unbiased estimable functions of hierarchical econometric model

This papers main purpose is an analysis of the intercontinental variations of Norwegian import expenditures based on yearly import data from 1988 to 2014. We apply the best linear unbiased estimable (BLUE) functions of the two-stage non-full rank hierarchical linear econometric model. The results confirm that the top three import-items across continents (in descending order) are machinery and transport equipment, manufactured goods classified mainly by material, and miscellaneous manufactured articles. These three import-items cover more than 60% of the Norwegian imports. Furthermore, the model predicts that Europe is the leading continent of these three important items of Norwegian imports. The European continent is therefore influential for the Norwegian trade pattern, while other continents show lack of stability and predictability. The results imply that any governmental (or private) trade stability programs have only marginal effects.

Parametric Survival Modelling of Risk Factor of Tuberculosis Patients under DOTS Program at Hawassa Town, Ethiopia

Tuberculosis (TB) is a chronic infectious disease that has a major health problem over the centuries. This study assessed the risk factors associated with time to death among TB patients treated under directly observed short course treatment program in Health facilities in Hawassa city, Ethiopia. The authors analysed data from a cohort of 1604 TB patients recruited between September 2008 to September 2011. They apply the parametric regression model of survival data analysis. The best fitted parametric regression model is selected by using the Akaike information criterion (AIC). The AIC confirms that the Weibull regression model is found to be the best fit of the survival of tuberculosis patients under the DOTS program at Hawassa town, Ethiopia. The fit of the Weibull regression model result revealed that sex, age, baseline weight, HIV status, category of patients and year of enrolment are the significant factor for the survival of TB patients. Parametric Survival Modelling of Risk Factor of Tuberculosis Patients under DOTS Program at Hawassa Town, Ethiopia

Econometric Modelling of the Variations of Norway’s Export Trade across Continents and over Time: The Two-Stage Non-Full Rank Hierarchical Linear Econometric Model Approach

This paper applies the two-stage hierarchical non-full rank linear econometric model to make a deep analysis based on revenue generated from key Norwegian export items over the world’s continents. The model’s ability to analyse the variation of Norway’s export trade gives us the following interesting details: (1) for each continent intra- and intervariation of export items, (2) access to deep knowledge about the characteristics of the Norway’s export items revenue, (3) quantifying the economic importance and sustainability of export items within continents; and finally (4) comparing a given export item economic importance across continents. The results suggest the following important policy implications for Norway. First, Europe is the most important trade partner for Norway. In fact, 81.5% of Norwegian export items are transported to Europe. Second, there is a structural shift in Norwegian exports from North and Central America to Asia and Oceania. Third, the new importance of Asia and Oceania is also emphasized by the 85% increase in export revenues over the period 1988–2012. The trade pattern has changed and trade policy must change accordingly. The analysis has shown that in 2012 there are two important export continents for Norway: Europe and Asia and Oceania.