argo carriers are obligated to reduce the CO₂ emissions that result from their cargo transportation activities. However, they tend to focus on reducing cargo transportation costs rather than CO₂ emissions. In addition, most cargo carriers entrust all their deliveries to subcontractors, and therefore, vehicle routing and cargo allocation that take only CO₂ emissions into consideration are not applicable for them. It is necessary to develop a method to determine cargo allocation and delivery routes for both the cargo carrier and their subcontractors. In our previous work, we proposed a method for solving a vehicle routing and cargo allocation problem where the cost and CO₂ emissions must be minimized. This method is not a global search but a hill-climbing method that adjusts a tentative cargo allocation with a low outsourcing fee, which is defined using a simple procedure. In this paper, we propose a method based on a harmony search algorithm. Experiments were conducted using both synthetic data and actual data provided by a cargo carrier in Japan. The results validate the utility of the proposed method.

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Cell formation is one of the important problems in design of a cellular manufacturing system. In recent years,many works had been carried out in this active research field. Specially, similarity coe fficient methods had been studied widely to form part-machine cells so as to minimize intercellular part movements, but few of them had considered inŽuence of operation sequences and times on cell formation simultaneously. In this paper, we improve an existing similarity coefficients based on considering the factors of operation sequences and operation times. A feasible and effective operation sequences and times-based similarity coefficient method is presented to solve cell formation problems. The improved method is applied to several examples from literatures and a numerical example with some repeated production processes. The results demonstrate that it is necessary to consider the operation sequences and times into similarity measure between each pair of parts or machines, and the proposed method is valid and available for cell formation in cellular manufacturing system with some repeated operations.

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Reducing CO₂ emissions is a very important mission in green transportation. In Japan about 20% of total CO₂ emissions are from transportation department. Modal shift from truck to railway or ship transportation is a good alternative because it may bring a lower environmental impact. In this paper, a geographical simulation model is constructed in where the advantageous areas of railway can be shown, comparing with truck transportation when the departure point is given. Three evaluating factors of transportation cost, delivery lead time and CO₂ emissions are combined into the geographical framework to clarify the advantageous areas totally by the modal shift. Simulation experiments are designed and executed based on the real data of Japanese companies, to show the performance and utility of the model.

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The purpose of this paper is to clarify the increase in Žexibility by introducing bu ffer stocks that enable modelsequence changes in a mixed-model assembly line. It is shown that changing the model sequences between stations can shorten the line length for a mixed-model assembly. Numerical analysis indicates that the range of possible operation time combinations of models can be increased and the model mix can be made more Žexible by introducing bu ffer stocks under the same line length. This phenomenon is also discussed from the viewpoint of the relationship between buffers and Žexibility. A procedure for examining feasible combinations of operation times is presented.

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The recent Great East Japan Earthquake and Thailand Žoodsmade the supply and procurement of parts di fficult and caused a downstream production stop. Such a stoppage of a supply chain results in the concerned mixed-production lines being thrown into confusion. Designing robust mixed-model assembly lines is one of the critical issues for responding effectively to supply and demand Žuctuations. In this study, the relationships between alteration of the mixing ratio and line length are considered under the assumption of the same planning period length. Based on these relationships, a procedure of designing a robust mixed-model assembly line is shown with a numerical analysis example.

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