Mitigating supply and production uncertainties with dynamic scheduling using real-time transport information

Supply and production uncertainties can affect the scheduling and inventory performance of final production systems. Facing such uncertainties, production managers normally choose to maintain the original production schedule, or follow the first-in-first-out policy. This paper develops a new, dynamic algorithm policy that considers scheduling and inventory problems, by taking advantage of real-time shipping information enabled by today’s advanced technology. Simulation models based on the industrial example of a chemical company and the Taguchi’s method are used to test these three policies under 81 experiments with varying supply and production lead times and uncertainties. Simulation results show that the proposed dynamic algorithm outperforms the other two policies for supply chain cost. Results from Taguchi’s method show that companies should focus their long-term effort on the reduction of supply lead times, which positively affects the mitigation of supply uncertainty

Factors associated with central overweight and obesity in students attending the University for Development Studies in Tamale, Ghana: a cross-sectional study

Objectives: This study assessed the prevalence of central overweight and obesity in students of the University for Development Studies in Tamale, Ghana. Lifestyle factors associated with central overweight and obesity were also investigated in this study population.Design: A cross-sectional study design was employed.Setting: School of Medicine and Health Sciences, University for Development Studies, Tamale, Ghana.Subjects: A sample of 552 students was randomly selected to participate.Method: Waist and hip circumference was measured with appropriate tools and computed into a waist-to-hip ratio (WHR). Demographic and socio-cultural factors, such as age, sex, smoking status and coffee and alcohol consumption, were recorded. Physical activity was assessed using the World Health Organization Global Physical Activity Questionnaire.Results: Generally, 29.3% of the participants had a normal WHR (44.1% males, 3.0% females). 60.9% (55.9% males, 69.7% females) were centrally overweight and 9.8% (0.0% males, 27.3% females) centrally obese. Age and smoking status were not associated with central overweight and obesity. Being female was significantly associated with a higher prevalence of central obesity. The prevalence of central obesity was 13.9% in non-coffee drinkers, 6.7% in coffee drinkers, 11% in non-alcohol drinkers and 0% in alcohol drinkers. Almost 95% of centrally obese participants engaged in light or moderate physical activity, and 5.6% in vigorous physical activity (p-value < 0.0001). Conversely, 55% of normal weight participants engaged in light or moderate physical activity and 44% in vigorous physical activity (p-value 0.0008).Conclusion: Physical activity, female gender, alcohol and coffee consumption were associated with central obesity.Keywords: alcohol consumption, central obesity, coffee consumption, Ghana, physical activity, Tamale, University students, WH

Mobile Internet and SMEs: a focus on the adoption

The purpose of this paper is to focus on the adoption of business to employee (B2e) mobile internet (MI) applications in Italian small and medium enterprises (SMEs). The purpose is twofold: to analyze the diffusion of these applications underlining the main adoption barriers and to describe the impact on the corporate environment and the decision-making process leading to the introduction of B2e MI application

Dynamic expediting of an urgent order with uncertain progress

A supplier manages an urgent order with uncertain progress for which her client has set a deadline for its completion. The supplier observes in real time the order progress and chooses dynamically the effort level, such as manpower level, to expedite the order. Her problem is to identify expediting policies to minimise her expected cost, given by two costs in trade-off with each other: an effort level cost and a one-time penalty cost for late completion of the order. We formulate this problem using a discrete stochastic dynamic programming framework and obtain an optimal expediting policy for it.By conducting a worst-case analysis, we show that decreasing the level of flexibility, interpreted as the supplier’s ability to update effort levels more often, may lead to a large increase in the costs of managing the order. We refine the problem formulation by modelling the case in which the supplier takes into account the negative effects of late order completion on her client using a penalty cost charged every period the order is delayed. We find an optimal policy for this case, by solving two dynamic programming problems sequentially. For both problems, we show that in presence of certain assumptions, there is an optimal expediting policy for which effort levels are non-increasing in the order progress. Finally, using a simulation study based on a car seat assembly case, we compare the performance of the two policies