Browsing by Author "Shibayama, Tomoya"

Now showing 1 - 3 of 3
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    Integrated Model for Estimating Sediment Discharge to Coastal Environment from River Basin
    (2006-01) Norbert, Joel; Shibayama, Tomoya
    In this study an integrated model to estimate total sediment discharge from the river basin to the coastal environment is developed. Simulated and measured sediments discharge at the river mouth is compared and there is a good agreement. Also the effect of land use and climate change to the sediment yield is analyzed. The land use data derived from remotely sensed images of 1976 and 1997 is used as the basis for comparison to see the effect of land use change. It was observed that using the land use data for the year 1997, total sediment discharge to the coastal environment increased as compared to the year 1976; this is mainly due to the increased agricultural areas and residential areas and also decreases in forest area. For analyzing the effect of climate change, HadCM2 model is used to generate mean daily precipitation for the month for the period 2040-2050 and then daily rainfall amount is generated from this data using exponential distribution. The results of the sediments discharge to the coastal environment using this generated data show a decrease in the average annual sediment discharge.
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    Management of Pavement Network Maintenance and Rehabilitation Planning Using Shuffled Complex Evolution
    (2007) Mturi, Matiko S.; Shibayama, Tomoya
    This paper presents an approach for optimization of segment-linked maintenance and rehabilitation plan for a pavement network by using shuffled complex evolution. It extends the works of Nunuo and Agyei (2000) by improving the exploration-exploitation balance of the algorithm and by using a realistic pavement deterioration model to solve the problem of multiple maintenance and rehabilitation activities. An example to maximize the serviceability of the road network under a fixed budget and minimum serviceability level policy is also presented. The result of the optimization process using a part of Kanagawa prefecture road network showed very good results with reasonable computational times.
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    Proposal of Simple Pavement Deterioration Model by Using In-Service Survey Data
    (2007-07) Mturi, Matiko S.; Shibayama, Tomoya
    In this paper a nonlinear deterministic flexible pavement performance model is presented. The model uses the maintenance control index calculated from in-service condition survey data as its independent variable, and pavement characteristics of initial condition, structure and traffic loading as its dependent or explanatory variables. The parameters of the model are estimated using Kanagawa Prefecture Road Network condition survey data. The results of the model show that the model reproduces correctly the actual in-service pavement deterioration trend. This model is simple in its expression, uses a simple estimation method, and uses readily available data, consequently reducing the cost of model estimation. It therefore, suggests a promising avenue for improving the pavement performance prediction and consequently the pavement management system.