In this study, we propose a tradable permit mechanism for mobility sharing system. if mobility sharing services allow users to take arbitrary trips, the overall efficiency of the service cannot be achieved. To solve this problem, this study proposes a tradable permit mechanism. We first propose the Vickrey-Clarke-Groves mechanism for mobility sharing. With this mechanism, this tradable permits system satisfies the strategy-proof and the efficient allocation. Next, we discuss the difference between single-minded bidders case and multiple bidders case. we show that the permits price is decomposed to the usage fee for leaving the port of origin and the income for arriving at the port of destination. Finally, we propose the solution algorithm of these problems and from the aspect of computational time, we show this algorithm is feasible.

View full abstract

 This paper presents a novel method that automatically extracts regions and tracks of vehicles from traffic video images observed even when local sunlight condition varies or at nighttime. The proposed method first generates “accumulated temporal subtraction images” by accumulating temporal subtraction images within a certain period, and removes shadows by counting the number of brightness change in the images. This process removes parts of vehicles, but the lacking parts are compensated by accumulating the accumulated temporal subtraction images after removing shadow. As a result, the vehicle's track is determined. Then, the vehicle region at a certain time is delineated by multiplying the track without shadow and a tentative vehicle region with shadow. Finally, the image is converted into bird-eye view images, and the velocity of a vehicle is estimated by subtracting vehicle's positions shown in two bird-eye view images. We applied the method to traffic video images observed in Kyoto, and it was found that F-value was 0.98, and accordingly the proposed method performs very accurately.

View full abstract

 A variety of risks and uncertainties are inherent in project contract. Shari'ah, the law of Islam, prohibits gharar and mysir which are concepts related to ‘uncertainty’. Therefore, project contract is in danger of violating Shari'ah. The conformity of a project contract with Shari'ah significantly concerns the manner in which uncertainties are dealt with. However, there has been no contemporary rigorous definition or legal interpretation of ‘Shari'ah compliance’ with the general consensus. Rather, the regional variety of legal interpretation of Shari'ah is observed. In this paper, a theoretical model of complete contract is proposed to assess the Shari'ah compliance of a typical project contract. In addition, Shari'ah compliance of some typical contractual arrangements in project contract is discussed based on the proposed model.

View full abstract

 In the last two decades, a large number of studies have attempted to develop spatial computable general equilibrium (SCGE) models based on new economic geography (NEG). Although these studies provide SCGE models with agglomeration economies, their framework is oversimplified for computational purposes and inconsistent with NEG. This study develops an SCGE model consistent with NEG that has the following two characteristics to overcome the shortcomings of previous studies: 1) this model considers vertical linkages (input-output linkages) as in Venables¹⁾, which ensures the theoretical consistency; 2) the stable equilibrium that emerges after implementation of policies can be obtained. Furthermore, we present a numerical example to demonstrate that our model can be applied to practical applications.

View full abstract

 The "Suez shift" of Asia-US east coast container route is progressing, and the Panama Canal will be expanded within several years. After the expansion, whether the Panama Canal path will regain lost ground or not will be the large influence on Japan, which is the nearest Asian country to the Panama Canal.
 Against this background, this study calculated the container volume ratio of Panama/Suez Canal path, analyzed the cause of "Suez shift" and estimated the container volume ratio after the expansion. The conclusions of this study were as follows: (1) the cause of the "Suez shift" were the differences of TEU capacities and tolls of the canal transiting ships, (2) the container volume via the Panama Canal would increase about 20% if TEU capacities of vessels which passes each canal would be the same level after the expansion.

View full abstract