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Nishi-Tokyo-shi, Japan

Komazawa University is one of the oldest universities in Japan. Its history starts in 1592, when a seminary was established to be a center of learning for the young monks of the Sōtō sect, one of the two main Zen Buddhist traditions in Japan.The university in Tokyo campus comprises eight faculties and 22 departments with a total of around 16,000 students. Also for students who wish to pursue advanced studies, each department has a graduate school except the Department of Radiological science. It also has seven research institutes and a Museum of Zen Buddhist Culture. Wikipedia.


Iida T.,Komazawa University | Zipkin P.,Duke University
Operations Research | Year: 2010

We consider a serial supply chain with one supplier and one retailer. Each obtains some demand forecast information, which may be shared or not. We investigate the members' benefits from sharing information. The forecasts follow a variant of the Martingale model of forecast evolution (MMFE). We construct a simple transfer-payment scheme to align the players' incentives with that of the overall system. The main finding is that, unless the players' incentives are aligned in this way, sharing information makes little sense. It might hurt one or the other player and the system as a whole. ©2010 INFORMS. Source


Suzuki S.,Komazawa University
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2011

Vagueness is a ubiquitous feature that we know from many expressions in natural languages. It can invite a serious problem: the Sorites Paradox. The aim of this paper is to proposed a new version of complete logic for vague predicates - salient-similarity-based vague predicate logic (SVPL) that can avoid the Sorites Paradox and give answers to all of the Semantic Question, the Epistemological Question and the Psychological Question given by Graff. © 2011 Springer-Verlag. Source


Iida T.,Komazawa University
International Journal of Production Economics | Year: 2015

Abstract This paper studies both the benefits of leadtime information and the interrelationships among demand forecast information, leadtime uncertainty, and leadtime information, for improving inventory control performance. To this end, it explicitly incorporates both leadtime information and demand forecast information into an inventory model although they have conventionally been dealt with individually in the literature. Specifically, it considers a periodic-review inventory model with uncertain leadtimes, in which both leadtime information and demand forecast information are available. The leadtime information is modeled as the information of the arrival of outstanding orders and the demand forecast information as the Martingale Model of Forecast Evolution (MMFE). The paper analyzes the way to use both leadtime information and demand forecast information for inventory control operations. Specifically, under certain conditions, the optimality of the state-dependent base-stock policy is shown, and an effective heuristic policy is developed. It also derives some managerial insights for exploiting both leadtime information and demand forecast information in the case where leadtimes are uncertain. For instance, while leadtime information itself significantly improves inventory control performance, it also enhances the benefits of demand forecast information. Specifically, the benefits of demand forecast information may significantly decrease as leadtime uncertainty increases. However, the decrease of the benefits of demand forecast information may be alleviated with leadtime information. © 2015 Elsevier B.V. All rights reserved. Source


We consider a discrete-time two-dimensional process {(Ln (1),Ln (2))} on ℤ+ 2 with a background process {Jn} on a finite set, where individual processes {Ln (1)} and {Ln (2)} are both skip free. We assume that the joint process {Yn}={(Ln (1),Ln (2)},Jn)} is Markovian and that the transition probabilities of the two-dimensional process {(Ln (1),Ln (2))} are modulated depending on the state of the background process {Jn}. This modulation is space homogeneous, but the transition probabilities in the inside of ℤ+ 2 and those around the boundary faces may be different. We call this process a discrete-time two-dimensional quasi-birth-and-death (2D-QBD) process, and obtain the decay rates of the stationary distribution in the coordinate directions. We also distinguish the case where the stationary distribution asymptotically decays in the exact geometric form, in the coordinate directions. © 2012 Springer Science+Business Media, LLC. Source


Hasegawa K.,Tokyo Metroplitan University | Hasegawa K.,Komazawa University | Matsuyama H.,Tokyo Metroplitan University | Tsuzuki H.,Ehime University | Sweda T.,Ehime University
Remote Sensing of Environment | Year: 2010

A new vegetation index, the Normalized Hotspot-signature Vegetation Index (NHVI), is proposed for a better quantitative estimation of leaf area index (LAI) than with the remotely sensed normalized difference vegetation index (NDVI), especially in the boreal forest. To obtain this new index, the Hotspot-Dark-spot index (HDS) (Lacaze et al., 2002) was introduced. HDS is calculated by the difference between the strongest vector (hotspot) and the weakest vector (dark-spot) of bi-directional reflectance, a given tract of vegetation returns in the reflecting solar position, and the geometric structure of the vegetation canopy, which are poorly represented by NDVI alone. The validity of NHVI was statistically tested using two field data sets of multi-angular observations and LAI from the boreal forests of Canada; one set was our own observations, and the other was from the Boreal Ecosystem-Atmosphere Study (BOREAS). The range of linear correspondence of NHVI with LAI is much wider than that of NDVI alone, indicating significant representation of leaf biomass in the canopy geometry captured by HDS. With the technical innovation of multi-angular remote-sensing and kernel-driven models in the future, this index has the potential to provide a more accurate evaluation of regional and global LAIs. © 2009. Source

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