Scheduling-Location (ScheLoc) problem is a new and interesting topic in manufacturing, considering location and scheduling decisions simultaneously. Most existing works focus on the deterministic problems. In practice, however, job-processing times are usually uncertain due to some factors. This paper investigates the stochastic parallel machine ScheLoc problem to minimise the weighted sum of the location cost and the expectation of the total completion time. A two-stage stochastic programming formulation is proposed, then the sample average approximation (SAA) method is adapted to solve the small-size problems. To efficiently address the large-scale problems, a genetic algorithm (GA) and a scenario-based heuristic are designed. Numerical experiments on 450 instances are conducted. Computational results show that the scenario-based heuristic outperforms SAA method and GA in terms of solution quality and computational time.
Online health communities allow doctors to fully use existing medical resources to serve remote patients. They broaden and diversify avenues of interaction between doctors and patients using Internet technology, which have built an online medical consultation market. In this study, the theory of supply and demand was adopted to explore how market conditions of online doctor resources impact price premiums of doctors’ online service. Then, we investigated the effect of the stigmatized diseases. We used resource supply and resource concentration to characterize the market conditions of online doctor resources and a dummy variable to categorize whether the disease is stigmatized or ordinary. After an empirical study of the dataset (including 68,945 doctors), the results indicate that: (1) the supply of online doctor resources has a significant and negative influence on price premiums; (2) compared with ordinary diseases, doctors treating stigmatized diseases can charge higher price premiums; (3) stigmatized diseases positively moderate the relationship between resource supply and price premiums; and (4) the concentration of online doctor resources has no significant influence on price premiums. Our research demonstrates that both the market conditions of online doctor resources and stigmatized diseases can impact price premiums in the online medical consultation market. The findings provide some new and insightful implications for theory and practice.
8 December 2006 in Journal of Combinatorial Optimization
As one of the most important grain protection policies in China, the minimum purchase price policy prevents the fluctuation of grain output and protects the interests of farmers by regulating the prices of major grain varieties. For developing countries with a shortage of agricultural resources, represented by China, an in-depth study on the implementation effect and public satisfaction of this policy is of great significance for promoting the sustainable development of the grain industry. Based on the interest demands of the government, farmers, grain enterprises and consumers, this paper constructs a policy satisfaction evaluation model based on the Analytic Hierarchy Process and Fuzzy Comprehensive Evaluation. The research shows that the implementation effect of this policy has promoted the sustainable development of China’s grain in four aspects: improving farmers’ enthusiasm for planting, optimizing the structure of supply and demand, reducing the adverse impact of disasters, and ensuring the steady increase of output. However, due to the differences in natural resources and folk customs, the implementation effect of this policy varies in different regions.
15 July 2014 in Journal of Combinatorial Optimization