696 research outputs found

    A Road Network Design Model Considering Node Capacity

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    Optimal road network design models have been investigated in order to generate alternatives of road network planning. Most of the previous works assume that the decision variables of the planners are the attributes of the links. The actual road network, however, consists of links and nodes, and it is useful to distinguish links and nodes explicitly. Planning models should involve the attributes of nodes in decision variables as well as the link attributes. We formulate a road network design model considering the nodal capacity. The frame of the proposed model is interpreted as a two level optimal problem, which is a system optimizing problem including an optimal problem as its constraint. Before the formulation of a two level problem, the structure of a node is simplified, and a nodal passing time function is introduced, which represents the performance of a node. As a user equilibrium is the most relevant assumption for the description of road network flow, the lower problem is formulated as a fixed demand user equilibrium problem, using nodal passing time functions as well as link travel time functions. Given the total investment cost constraint, the higher problem decides the link and nodal capacities in order to optimize a measure of the whole network performance. The lower problem describes the traffic flow on a network for given capacities. The structure of the model is explained by using the frame of the Stackelberg differential game, whose players are planner (leader) and aggregate term of network user (follower). In order to solve the formulated problem, a heuristic algorithm is proposed. This is the input/outputiterativemethod, and it is expected to be effective for a normal size problem. The convergence of the algorithm is numerically confirmed through an example for simple and hypothetical datum. A sensitivity analysis for the value of the cost constraint is executed to determine the effective value of an investment. Remaining problems are extensively discussed for further research

    Compressive Deformation Process of Japanese Cedar (Cryptomeria Japonica)

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    We examined the compressive deformation behavior, and methods of compression fixation were considered. Furthermore, we examined the mechanical characteristics of compressed wood for each method of fixation and each compression ratio. As a result of the examination, the deformation behavior was found to differ depending on the direction of compression. The deformation progressed without causing destruction in compression into the tangential surface, but compression into the radial surface caused partial buckling of the cell walls in the process of deformation. The compression stress showed the tendency to decrease as the temperature and moisture content increased. Steam treatment by the closed heating method was compared with heat treatment by the open heating method as methods of fixation. The closed heating method was found to be effective for deformation fixation in a short time. As the result of the mechanical properties of compressed wood, the moduli of rupture (MOR) and elasticity (MOE) increased as the compression ratio increased, and they showed the tendency to be roughly proportional to the increase in density. However, hardness increased only nominally up to 40 % compression and then increased rapidly from 40 %. Moreover, in 480-min heat treatment by open heating, the influence of heat deterioration on impact-absorbed energy was found

    Signatures of self-organized criticality in spontaneous walking behavior of Porcellio scaber

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    The 11th International Symposium on Adaptive Motion of Animals and Machines. Kobe University, Japan. 2023-06-06/09. Adaptive Motion of Animals and Machines Organizing Committee.Poster Session P6

    Input and output budgets of radiocesium concerning the forest floor in the mountain forest of Fukushima released from the TEPCO's Fukushima Dai-ichi nuclear power plant accident

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    AbstractEstimations of radiocesium input and output concerning the forest floor within a mountain forest region have been conducted in the north and central part of the Abukuma Mountains of Fukushima, northeast Japan, after a 2–3 year period following the TEPCO Fukushima Dai-ichi nuclear power plant accident. The radiocesium input and output associated with surface washoff, throughfall, stemflow, and litterfall processes at experimental plots installed on the forest floor of evergreen Japanese cedars and deciduous Konara oaks have been monitored. Despite the high output potential in the mountainous forest of Fukushima, the results at both monitoring locations show the radiocesium input to be 4–50 times higher than the output during the summer monsoon in Fukushima. These results indicate that the radiocesium tends to be preserved in the forest ecosystem due to extremely low output ratios (0.05%–0.19%). Thus, the associated fluxes throughout the circulation process are key issues for the projecting the environmental fate of the radiocesium levels, along with the subsequent reconstruction of life emphasized within the setting
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