• 제목/요약/키워드: Hotspot

검색결과 261건 처리시간 0.026초

모바일 핫스팟을 위한 이동무선백홀 기술동향 분석 (Trend Analysis of Moving Wireless Backhaul Technologies for Mobile Hotspot Networks)

  • 정희상;조대순;최성우;최승남;오현정;김준형;회빙;신성문;김일규;방승찬
    • 전자통신동향분석
    • /
    • 제30권1호
    • /
    • pp.12-20
    • /
    • 2015
  • 1980년대 초 1세대 아날로그 이동통신시스템이 처음 도입된 이래 이동통신은 2세대, 3세대를 거쳐서 4세대 시스템으로 진화되었다. 기존의 이동통신은 주로 가정, 사무실 등 보행자 중심의 Nomadic 환경에 최적화된 형태이고 120km/h 이상의 고속환경에서는 통신접속이 끊어지지 않는 정도의 서비스에 한정되었다. 2007년 애플의 iPhone이 출현한 이래 스마트폰 중심의 모바일 데이터 서비스 사용량이 매년 가파른 증가세를 보이고 있으며 보행자 중심의 저속환경뿐만 아니라 지하철, 고속철 등 그룹이동체 내에서의 모바일 데이터 서비스도 점차 중요해지고 있다. 그룹이동체 내에서 일반 사용자들은 차량 외부의 이동통신망을 통해 직접 서비스를 받을 수도 있고 이동무선백홀과 결합된 WLAN 혹은 펨토셀과 같은 차량 내 이동소형셀형태로 서비스를 받을 수 있다. 본고에서는 그룹이동체 내의 이동소형셀 지원을 위한 이동무선백홀 기술동향을 분석하고 향후 수 Gbps급 이상의 데이터 전송속도를 지원할 수 있는 밀리미터파 기반의 이동무선백홀 기술을 소개한다.

  • PDF

The Effects of Repetitive Transcranial Magnetic Stimulation on the Gait of Acute Stroke Patients

  • Ji, Sang-Goo;Kim, Myoung-Kwon
    • Journal of Magnetics
    • /
    • 제20권2호
    • /
    • pp.129-132
    • /
    • 2015
  • The aim of the present study was to examine whether repetitive transcranial magnetic stimulation (rTMS) can improve gait ability of acute stage stroke patients. This study was conducted with 39 subjects who were diagnosed as having a hemiparesis due to stroke. The experimental group included 20 subjects who underwent repetitive transcranial magnetic stimulation and the control group included 19 subjects who underwent sham therapy. The stroke patients in the experimental group underwent conventional rehabilitation therapy and rTMS was applied daily to the hotspot of the lesional hemisphere. The stroke patients in the control group underwent sham rTMS and conventional rehabilitation therapy. Participants in both groups received therapy five days per week for four weeks. Temporospatial gait characteristics, such as stance phase, swing phase, step length in affected side, velocity, and cadence, were assessed before and after the four week therapy period. A significant difference was observed in post-treatment gains for the step length in the affected side, velocity, and cadence between the experimental group and control group ( p < 0.05). However, no significant differences were observed between the two groups on stance phase and swing phase ( p > 0.05). We conclude that rTMS may be beneficial in improving the effects of acute stage stroke on gait ability.

Assessing Spatial Disparities and Spatial-Temporal Dynamic of Urban Green Spaces: a Case Study of City of Chicago

  • Yang, Byungyun
    • 한국측량학회지
    • /
    • 제38권5호
    • /
    • pp.487-496
    • /
    • 2020
  • This study introduces how GISs (Geographic Information Systems) are used to assess spatial disparities in urban green spaces in the Chicago. Green spaces provide us with a variety of benefits, namely environmental, economic, and physical benefits. This study seeks to explore socioeconomic relationships between green spaces and their surrounding communities and to evaluate spatial disparities from a variety of perspectives, such as health-related, socioeconomic, and physical environment factors. To achieve this goal, this study used spatial statistics, such as optimized hotspot analysis, network analysis, and space-time cluster analysis, which enable conclusions to be drawn from the geographic data. In particular, 12 variables within the three factors are used to assess spatial disparities in the benefits of the use of green spaces. Finally, the variables are standardized to rank the community areas and identify where the most vulnerable community areas or parks are. To evaluate the benefits given to the community areas, this study used the z- and composite scores, which are compared in the three different combinations. After identifying the most vulnerable community area, crime data is used to spatially understand when and where crimes occur near the parks selected. This work contributes to the work of urban planners who need to spatially evaluate community areas in considering the benefits of the uses of green spaces.

A Game Theory Based Interaction Strategy between Residential Users and an Electric Company

  • Wang, Jidong;Fang, Kaijie;Yang, Yuhao;Shi, Yingchen;Xu, Daoqiang;Zhao, Shuangshuang
    • Journal of Electrical Engineering and Technology
    • /
    • 제13권1호
    • /
    • pp.11-19
    • /
    • 2018
  • With the development of smart grid technology, it has become a hotspot to increase benefits of both residential users and electric power companies through demand response technology and interactive technology. In this paper, the game theory is introduced to the interaction between residential users and an electric company, making a mutually beneficial situation for the two. This paper solves the problem of electricity pricing and load shifting in the interactive behavior by building the game-theoretic process, proposing the interaction strategy and doing the optimization. In the simulation results, the residential users decrease their cost by 11% mainly through shifting the thermal loads and the electric company improves its benefits by 5.6% though electricity pricing. Simulation analysis verifies the validity of the proposed method and shows great revenue for the economy of both sides.

밀집 무선랜 시스템에서의 멀티캐스트 전송 스케줄링 기법 (Multicast Scheduling Scheme in Dense WLAN Systems)

  • 김나명;김원중;백상헌
    • 한국통신학회논문지
    • /
    • 제40권3호
    • /
    • pp.441-450
    • /
    • 2015
  • 최근 무선 디바이스의 증가와 무선랜 사용자가 급증하면서 다수의 AP와 여러 노드가 존재하는 밀집 네트워크 환경이 발생한다. 다수의 AP가 존재하는 환경에서 중첩영역에 대한 고려 없이 멀티캐스트 데이터를 전송할 경우 노드의 위치에 따라서 메시지 중복 수신과 빈번한 데이터 충돌이 발생할 수 있다. 본 논문에서는 밀집 무선랜 시스템에 적합한 새로운 멀티캐스트 전송 스케줄링 기법을 제안한다. 제안하는 멀티캐스트 전송 기법은 단일 전송환경과 다중 전송 환경을 모두 고려하며 각 AP의 최적의 전송 순서를 스케줄링 함으로써 불필요한 중복전송을 제거하고 데이터 충돌을 방지한다. 시뮬레이션 결과를 통하여 제안하는 기법이 비교 기법들에 비해서 전송시간이 감소하고, 밀집 네트워크 환경에서 효율적인 멀티캐스트 전송을 하는 것을 확인할 수 있다.

컴포넌트기반 방법론을 사용한 프레임워크 개발에 관한 연구 (A Study on the Development of Framework Using Component Based Methodology)

  • 김행곤;한은주
    • 한국정보처리학회논문지
    • /
    • 제7권3호
    • /
    • pp.842-851
    • /
    • 2000
  • Developers can reuse not only class code but also wide range of knowledge on domain by reusing framework. Existing Object-Oriented Methodology and Catalysis Methodology were presented when redefining component in the course of redesigning framework. However, existing methodologies have weakness that entire process is waterfall mode or design of interface lays too much stress on implementation stage. So, this thesis will present Component-Oriented Methodology for the reuse of framework, and construct the environment for framework and domain development. That is, domain is analyzed by input of domain knowledge on real world to create software based on component, and hotspot is identified through analyzed information, and refactoring by putting additional information on users and developers. After that, I will create domain framework and application framework depending on domain. In this Component-Oriented Methodology, information is searched, understood and extracted or composite through component library storage internally. Then this information is classified into the information on component, and used as additional information in redesigning. With this, developer can obtain reusability, easiness and portability by constructing infrastructure environment that allows to register, update and delete component through Component Management System(CMS) under he development environment which can be easily applied to his own application using framework component, in this thesis, CoRBA(Common Object Request Broker Architecture) environment.

  • PDF

군집분석을 통한 노인 보행자 사고 취역지역 선정방법에 관한 연구 (The Study of selection method about Elderly Pedestrian Hotspot by Cluster Analysis)

  • 고은혁;윤병조;박형근;양승룡
    • 한국재난정보학회:학술대회논문집
    • /
    • 한국재난정보학회 2015년 정기학술대회
    • /
    • pp.193-194
    • /
    • 2015
  • 본 연구는 요인분석을 통해 노인 보행자 사고 유형을 대표할 수 있는 성분 값을 계산하고 군집분석을 실시하여 노인 보행자 사고 취약 지역을 선정하는 모델을 확인하였다. 기존 노인보행자 사고에 관한 연구는 보행 환경 분석 및 노인보행자 사고 특성을 확인한 뒤, 제도적, 물리적 환경 개선 등에 대한 정책 제언의 형식으로 진행되었다. 이러한 연구는 실질적으로 노인 보행자 특성을 분석하여 사고를 감소시키는 연구가 아닌, 일반적으로 알려진 사실이나 해외 사례를 들어 노인 보행자 사고의 현 실태에 대해 어느 정도 환기만 시켜주는 역할로 그쳤다. 이러한 점에서 군집분석을 통한 노인 보행자 사고 취약지역 선정은 노인 보행자 사고 특성의 비교를 명확하게 할 수 있도록 새로운 기준을 제시하였다. 이에 기존의 방법론에서 벗어나 실질적으로 노인 보행자 사고 방지 대책이 시급한 지역을 선정하였고, 노인 보행자 사고에 관해 활발히 연구 시킬 것이라 예상한다. 군집분석을 사용하는 핵심은 사망자 수와 사망률이 상대적으로 동시에 높은 군집을 선정할 수 있고 지역 특성 비교를 통해 향후 노인 보행자 사고에 관한 추가 연구가 가능할 것으로 기대한다.

  • PDF

Ten New Recorded Species of Macrofungi on Ulleung Island, Korea

  • Park, Myung Soo;Cho, Hae Jin;Kim, Nam Kyu;Park, Jae Young;Lee, Hyun;Park, Ki Hyeong;Kim, Min-Ji;Kim, Jae-Jin;Kim, Changmu;Lim, Young Woon
    • Mycobiology
    • /
    • 제45권4호
    • /
    • pp.286-296
    • /
    • 2017
  • Ulleung Island is a biodiversity hotspot in South Korea. During a survey of indigenous fungal species from Ulleung Island conducted from 2015 to 2016, we discovered 10 unrecorded macrofungi in Korea. These macrofungi were identified to the species level using morphological features and phylogenetic analysis based on the internal transcribed spacer region: Deconica phyllogena, Mycena zephirus, Phaeomarasmius proximans, Phlebia radiata, Pluteus semibulbosus, Postia alni, Resinicium pinicola, Scytinostroma portentosum, Tricholomopsis flammula, and Tyromyces kmetii. We also provide detailed morphological descriptions for these 10 species.

A Multi-Scale Parallel Convolutional Neural Network Based Intelligent Human Identification Using Face Information

  • Li, Chen;Liang, Mengti;Song, Wei;Xiao, Ke
    • Journal of Information Processing Systems
    • /
    • 제14권6호
    • /
    • pp.1494-1507
    • /
    • 2018
  • Intelligent human identification using face information has been the research hotspot ranging from Internet of Things (IoT) application, intelligent self-service bank, intelligent surveillance to public safety and intelligent access control. Since 2D face images are usually captured from a long distance in an unconstrained environment, to fully exploit this advantage and make human recognition appropriate for wider intelligent applications with higher security and convenience, the key difficulties here include gray scale change caused by illumination variance, occlusion caused by glasses, hair or scarf, self-occlusion and deformation caused by pose or expression variation. To conquer these, many solutions have been proposed. However, most of them only improve recognition performance under one influence factor, which still cannot meet the real face recognition scenario. In this paper we propose a multi-scale parallel convolutional neural network architecture to extract deep robust facial features with high discriminative ability. Abundant experiments are conducted on CMU-PIE, extended FERET and AR database. And the experiment results show that the proposed algorithm exhibits excellent discriminative ability compared with other existing algorithms.

Newly recorded ferns from the flora of Myanmar in Natma Taung National Park

  • NWE, Thet Yu;MOON, Myung-Ok;LEE, Seung-Hoon;SUN, Byung-Yun
    • 식물분류학회지
    • /
    • 제49권1호
    • /
    • pp.8-12
    • /
    • 2019
  • Although Myanmar is a biodiversity hotspot, little is known about its flora, particularly lycophytes and ferns, due to a lack of intensive inventories. In 2017, work on a total of 299 species of lycophytes and ferns found throughout the country, including 84 species from Natma Taung National Park in the Chin State, was published. However, a comparison of the flora of Myanmar with those of adjacent countries suggests that many more species are likely also to be distributed in this country. In the present study, two field surveys conducted in Natma Taung National Park during 2015 to make a checklist of lycophytes and ferns resulted in the discovery of three fern species not previously recorded in the flora of Myanmar. All occur in other countries in Southeast Asia as well as in other tropical areas. These species are Pteris bella (Pteridaceae), Dryopteris lepidopoda (Dryopteridaceae), and Loxogramme duclouxii (Polypodiaceae). The results will provide valuable information for the Myanmar fern checklist that is currently being prepared.