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EN
The problem of attaching dynamic vibration absorber (DVA) to a discrete multi-degree-of-freedom or continuous structure has been outlined in many papers and monographs. An impact damping system can overcome some limitations by impact as the damping medium and impact mass interaction as the damping mechanism. The paper contemplates the provision of DVA with the several of the impact masses. Such originally designed absorbers reduce vibration selectively in maximum vibration mode without introducing vibration in other modes. An impact damper is a passive control device which takes the form of a freely moving mass, constrained by stops attached to the structure under control, i.e. the primary structure. The damping results from the exchange of momentum during impacts between the mass and the stops as the structure vibrates. The paper contemplates the provision of the impact multi-mass DVA’s with masses collisions for additional damping. For some cases of DVA optimization such a design seems more effective than conventional multi-mass DVA with independent mass moving. A technique is developed to give the optimal DVA’s for the elimination of excessive vibration in harmonic stochastic and impact loaded systems.
EN
We consider a logistic planning problem for simultaneous optimization of the storage and the delivery. This problem arises in the consolidate shipment using an intermediate storage in a supply chain, which is typically found in the automobile industry. The vehicles deliver the items from the origin to the destination, while the items can be stored at some warehousing facilities as the intermediate storage during the delivery. The delivery plan is made for each day separately, but the storage at a warehouse may last for more than one day. Therefore, the entire logistic plan should be considered over a certain period for the total optimization. We formulate the storage and delivery problem as a mixed integer programming. Then, we propose a relax-and-fix type heuristic method, which incrementally fixes decision variables until all the variables are fixed to obtain a complete solution. Moreover, a semiapproximate model is introduced to effectively fix the variables. Based on the formulation, the delivery plan can be solved for each day separately. This has the advantage especially in the dynamic situation, where the delivery request is modified from the original request before the actual delivery day. Numerical experiments show that the simultaneous optimization gives the effective storage plan to reduce the total logistic cost, and the proposed heuristics efficiently reduce the computational time and are robust against the dynamic situation.
EN
In this study we address the preliminary design for the module layout and bill conveyance routes of automatic teller machines (ATMs). We determine a two-dimensional layout for the modules as below that are approximately rectangular if the ATM is viewed from the side. ATMs require the compact placement of modules within the chassis and conveyance routes that smoothly circulate bills. However, the intersection and overlapping of routes by which the bills are conveyed in opposite directions are not allowed. Applying the bottom-left method and route-design-oriented packing method to the layout of the modules and the direction-oriented maze routing expediting branching and interflow of routes to the bill conveyance route, the application orders are optimized simultaneously using genetic algorithms (GAs). Results show that suitable designs for the ATM including the case when modules are selected as well as placed are achievable using the above simultaneous optimization. The design intention is expressible by changing the weights associated with chassis dimensions, route lengths and the number of route bends, which compose the objective function. The proposed method is useful for efficiently advancing the preliminary design of ATMs. Finally, if island models pursuing individual targets are used along with a GA, the design becomes even more efficient.
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