AN APPLICATION OF THE RATIONAL EXPECTATIONS HYPOTHESIS IN THE U.S. BEEKEEPING INDUSTRY

A national beekeeping-industry model, assuming rational expectations, is presented. Consistent and asymptotically efficient estimates are obtained by a modified two-step two-stage least squares method. Based on parameter estimates, elasticities, and likelihood functions, a previously estimated modified adaptive expectations model explains industry behavior better than the rational expectations model. Simulation analyses of the models suggest the direction of the impacts of an ineffective federal honey support program from 1982 through 1985 is similar but the magnitudes are varied. The rational expectations model indicates the decrease in beekeepers' revenue in this period is larger than the decrease identified by the modified adaptive expectations model.Farm Management,

Scheduling Performance Evaluation of Logistics Service Supply Chain Based on the Dynamic Index Weight

Scheduling is crucial to the operation of logistics service supply chain (LSSC), so scientific performance evaluation method is required to evaluate the scheduling performance. Different from general project performance evaluation, scheduling activities are usually continuous and multiperiod. Therefore, the weight of scheduling performance evaluation index is not unchanged, but dynamically varied. In this paper, the factors that influence the scheduling performance are analyzed in three levels which are strategic environment, operating process, and scheduling results. Based on these three levels, the scheduling performance evaluation index system of LSSC is established. In all, a new performance evaluation method proposed based on dynamic index weight will have three innovation points. Firstly, a multiphase dynamic interaction method is introduced to improve the quality of quantification. Secondly, due to the large quantity of second-level indexes and the requirements of dynamic weight adjustment, the maximum attribute deviation method is introduced to determine weight of second-level indexes, which can remove the uncertainty of subjective factors. Thirdly, an adjustment coefficient method based on set-valued statistics is introduced to determine the first-level indexes weight. In the end, an application example from a logistics company in China is given to illustrate the effectiveness of the proposed method

A computational tool for analysing the response of complex heat exchanger networks to disturbances

The heat exchanger networks (HEN) in industrial heat recovery systems often consist of large and complex subsystems. Calculating the response of such HENs to disturbances, such as varying inlet conditions or changing heat transfer capacities, may be challenging due to the presence of, e.g. stream splits and recycle loops. Extensive modelling and/or trial and error calculations may be necessary. This applies also for the analysis of different retrofit proposals. Retrofit opportunities in industrial heat recovery systems are often constrained by operability considerations, i.e. retrofit actions are supposed to have as little impact as possible on the production process to maintain the quality of the core product. Consequently, there is a clear demand for a tool to effectively screen design proposals at an early stage in the design process. In this work, a computational analysis tool is proposed to meet this demand. The proposed analysis tool allows fast evaluation of the network response when operating conditions change and/or operational settings are manipulated, and it is applicable for a wide range of HEN structures. The practical use of the analysis tool is demonstrated in a case study on the HENs of a large state-of-the-art Kraft pulp mill

Integrated Location-Production-Distribution Planning in a Multiproducts Supply Chain Network Design Model

This paper proposes integrated location, production, and distribution planning for the supply chain network design which focuses on selecting the appropriate locations to build a new plant and distribution center while deciding the production and distribution of the product. We examine a multiechelon supply chain that includes suppliers, plants, and distribution centers and develop a mathematical model that aims at minimizing the total cost of the supply chain. In particular, the mathematical model considers the decision of how many plants and distribution centers to open and where to open them, as well as the allocation in each echelon. The LINGO software is used to solve the model for some problem cases. The study conducts various numerical experiments to illustrate the applicability of the developed model. Results show that, in small and medium size of problem, the optimal solution can be found using this solver. Sensitivity analysis is also conducted and shows that customer demand parameter has the greatest impact on the optimal solution

A computational tool for guiding retrofit projects of industrial heat recovery systems subject to variation in operating conditions

Heat exchanger networks (HEN) in industrial heat recovery systems often consist of large and complex subsystems. Usually, such HENs are subject to variation in operating conditions, such as varying inlet conditions or changing heat capacity flow rates. Additionally, complexities such as stream splits and recycle loops are commonly present in industrial HENs. Therefore, extensive modelling and/or analytical calculations may be necessary when analyzing different retrofit proposals. Furthermore, retrofit opportunities in industrial heat recovery systems are often constrained by operability considerations, i.e. retrofit actions are supposed to have as little impact as possible on the production process to maintain the quality of the core product. In this work, a computational analysis tool is proposed for effective screening of HEN retrofit design proposals at an early stage in the design process. The proposed tool enables fast evaluation of the network\u27s response, i.e. temperatures and heat loads, when operating conditions change and/or operational settings are manipulated, and it is applicable for a wide range of HEN structures. The practical use of the analysis tool is demonstrated in a case study on the HENs of a large modern Kraft pulp mill