http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
A Satellite Resource Allocation for Multi-Beam Satellite Communication System
Sagawa, Yuichi,Ohata, Kohei,Ueba, Masazumi 통신위성우주산업연구회 2003 Joint Conference on Satellite Communications Vol.2003 No.-
A multi-beam system is one solution for enlarging the communication capacity by re-using the limited system frequency band, but system resources should be allocated to each user considering the interferences from vicinity beams(users). In addition, in mobile satellite systems, the resource allocation must consider user mobility and the uneven user distribution in the system and each beam. In this paper, we analyze an FDMA based multi-beam satellite system resource allocation scheme that considers both inter-beam interference and user distribution in the system in controlling both forward link power and frequency simultaneously. We confirm that this scheme enhances system capacity relative to the CDMA system, which uses the entire system frequency band.
Simulation of Seagrass Bed Mapping by Satellite Images based on the Radiative Transfer Model
Tatsuyuki Sagawa,Teruhisa Komatsu 한국해양과학기술원 2015 Ocean science journal Vol.50 No.2
Seagrass and seaweed beds play important roles in coastal marine ecosystems. They are food sources and habitats for many marine organisms, and influence the physical, chemical, and biological environment. They are sensitive to human impacts such as reclamation and pollution. Therefore, their management and preservation are necessary for a healthy coastal environment. Satellite remote sensing is a useful tool for mapping and monitoring seagrass beds. The efficiency of seagrass mapping, seagrass bed classification in particular, has been evaluated by mapping accuracy using an error matrix. However, mapping accuracies are influenced by coastal environments such as seawater transparency, bathymetry, and substrate type. Coastal management requires sufficient accuracy and an understanding of mapping limitations for monitoring coastal habitats including seagrass beds. Previous studies are mainly based on case studies in specific regions and seasons. Extensive data are required to generalise assessments of classification accuracy from case studies, which has proven difficult. This study aims to build a simulator based on a radiative transfer model to produce modelled satellite images and assess the visual detectability of seagrass beds under different transparencies and seagrass coverages, as well as to examine mapping limitations and classification accuracy. Our simulations led to the development of a model of water transparency and the mapping of depth limits and indicated the possibility for seagrass density mapping under certain ideal conditions. The results show that modelling satellite images is useful in evaluating the accuracy of classification and that establishing seagrass bed monitoring by remote sensing is a reliable tool.
Yoshimasa Sagawa,Coline Guilhendou,Thierry Moulin,Antonio Vinicius Soares,Pierre Decavel 한국운동재활학회 2024 JER Vol.20 No.2
The rehabilitation process of people with multiple sclerosis (PwMS) is a challenge, and decision-making requires a thorough assessment to increase the chances of success in rehabilitation planning. The aim of this study was to investigate the importance of the neuro-orthopaedic checkUp (NOChU) for gait prognosis. Participated in the study 105 PwMS with different levels of impairment. The NOChU includes measurements of passive range of motion (ROM), muscle strength, and spasticity. Additionally, was carried out the spatial-temporal analysis of the walking, Timed Up and Go test, and 6-min walk test. ROM remained relatively preserved to perform daily life activities except for ankle dorsiflexion. Muscle strength was also relatively preserved. Spasticity affected especially the ankle muscles, clearly the sural triceps. Among the NOChU measurements the catch seemed to have the most impact on walking on its different phases and on other activities. Accurate NOChU measurements play a crucial role in clinical settings, guiding informed decisions in rehabilitation planning. Future research endeavours could focus on exploring the correlations between NOChU deficiencies and the decline in walking capabilities among PwMS, with the goal of proposing personalized treatment strategies that address their specific requirements.