• 제목/요약/키워드: coordinator

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소형 셀 환경에서 유틸리티 최대화를 위한 분산화된 방법의 기지국 전송 전력 제어 (Distributed BS Transmit Power Control for Utility Maximization in Small-Cell Networks)

  • 이창식;김지환;곽정호;김은경;정송
    • 한국통신학회논문지
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    • 제38A권12호
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    • pp.1125-1134
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    • 2013
  • 최근 많은 수의 모바일 유저와 과도한 트래픽 증가를 해결하기 위한 솔루션으로 피코 혹은 펨토 셀과 같은 소형 셀을 설치하는 방법이 주목 받고 있다. 그러나 소형 셀에 속한 엣지 유저들은 주변 기지국으로부터 극심한 셀간 간섭을 받기 때문에 낮은 평균 전송률을 얻게 되고, 이를 해결하기 위해서는 셀 간 간섭을 효과적으로 관리하는 방법이 필요하다. 최근의 많은 연구들은 셀 간 간섭 관리를 위해 기지국의 전송 전력을 제어하는 알고리즘을 제시하였지만, 제시된 방법들은 높은 복잡도를 가지고 중앙 기지국의 도움을 필요로 한다는 단점이 있다. 본 연구에서는 기지국간의 경쟁을 기반으로 하여, 낮은 복잡도를 가지는 분산화된 방법의 기지국 전송 전력 on/off 제어 및 유저 스케줄링 알고리즘을 제안한다. 시뮬레이션 결과를 통해, 제안하는 방법이 셀 간 간섭 관리를 하지 않는 방법에 비해 셀 엣지 유저의 경우 170%의 성능 개선을 보이고, 최적의 알고리즘과 비교 했을 때 88-96%에 달하는 geometric average throughput (GAT) 성능 및 매우 근접한 average edge user throughput (AET) 성능을 보임을 검증한다.

무선환경에서의 이동객체 관리를 위한 통제기법: 공항 안전통제 업무를 중심으로 (A Transaction Scheme for Managing Mobile Units in Wireless Environments: A Case of Airport Safety Control)

  • 김용재;안현섭;이석준;현두운;최용구;이석원
    • 경영정보학연구
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    • 제10권2호
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    • pp.309-327
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    • 2008
  • 이 연구는 한국에 위치한 어느 공항의 프로젝트를 수행하는 가운데 도출된 결과다. IT 솔루션들을 놓고 검토한 결과, 레거시 정보시스템을 흡수하며 동시에 안전 수준을 향상시키는 시스템을 구축하기 위해서, PCS에 기반을 둔 모바일 데이터베이스 도입을 고려하면서 동반되는 물리적인 제약과 기술적인 문제들을 검토하고, 모바일 환경에서의 트랜잭션을 처리해 주는 두 가지 선택에 대하여 비교한다. 현재까지 알려진 문헌연구와 시뮬레이션 스터디를 통해서 이들 기술을 비교한 다음, 트랜잭션 프로세싱코디네이터 마이그레이션에 대한 방법을 제시하며, 기술이 가진 한계를 현실적 환경에서 검토해 본다.

보건소내 물리치료실 운영실태와 물리치료사의 배치방안 (A Study on the Operation and Use of Physiotherapy room at Public Health Service Center)

  • 송명수;김성일;송미화;박선아
    • 대한물리치료과학회지
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    • 제6권4호
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    • pp.263-274
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    • 1999
  • The public health service center and its branch are, as one of public institution, responsible for providing non-profitable medical service to local residents, which can't be addressed by private medical institutes. In addition, as a planning coordinator, they need to manage local medical resources effectively to make sure local residents can be offered good-quality health service fairly and impartially. The purpose of this study was to highlight the importance of physical therapy in public health service center's successful role performance, one of treatment to which local residents had a direct access. For attaining the purpose, an investigation was made into the actual facilities of public health service center and its branches in North Cholla province, the extent of use of physicaltherapy room, and the general characteristics of physical therapists. And literatures concerned were referred to. As a result, the dominant opinion was that the current physicaltherapy room shoulder be more reinforced(38.9%) or that it should he kept as it was(46.5%). Besides, the physical therapists investigated still were serving in a poor working condition. To elevate the quality and quantity of medical service, the current way to employ expert personnels temporarily or not to guarantee the position of physiotherapists should be removed immediately. Instead, physicaltherapists should be employed as regular public official. As, in home-visit project, physiotherapist are expected to play a bigger role in rehabilitation care or the management of patients with chronic disease, the physicaltherapy room should be increased and more physicaltherapists should be provided to health service institutions.

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Energy-efficient Relay MAC with Dynamic Power Control in Wireless Body Area Networks

  • Cai, Xuelian;Yuan, Jingjing;Yuan, Xiaoming;Zhu, Wu;Li, Jiandong;Li, Changle;Ullah, Sana
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제7권7호
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    • pp.1547-1568
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    • 2013
  • Wireless body area network (WBAN) is an emerging short-range wireless communication network with sensor nodes located on, in or around the human body for healthcare, entertainment and ubiquitous computing. In WBANs, energy is severely constrained which is the prime consideration in the medium access control (MAC) protocol design. In this paper, we propose a novel MAC protocol named Energy-efficient Relay MAC with dynamic Power Control (ERPC-MAC) to save energy consumption. Without relying on the additional devices, ERPC-MAC employs relaying nodes to provide relay service for nodes which consume energy fast. Accordingly the superframe adjustment is performed and then the network topology can be smoothly switched from single-hop to multi-hop. Moreover, for further energy saving and reliability improvement, the dynamic power control is introduced to adjust the power level whenever a node transmits its packets to the coordinator or the relaying node. To the best of the authors' knowledge, this is the first effort to integrate relay, topology adjustment and power control to improve the network performance in a WBAN. Comprehensive simulations are conducted to evaluate the performance. The results show that the ERPC-MAC is more superior to the existing standard and significantly prolongs the network lifetime.

웃음요법이 방사선요법을 받는 유방암 여성의 우울, 불안, 스트레스에 미치는 효과 (The Effect of Laughter Therapy on Depression, Anxiety, and Stress in Patients with Breast Cancer Undergoing Radiotherapy)

  • 김소희;김연희;김화정;이순행;유시온
    • 종양간호연구
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    • 제9권2호
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    • pp.155-162
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    • 2009
  • Purpose: The purpose of this study was to investigate the of laughter therapy on depression, anxiety, and stress among patients underwent radiotherapy. Methods: Participants in the study were comprised of 60 breast cancer outpatients who received radiotherapy. Thirty-one of the patients were assigned in the experimental group and the other 29 patients made up the control group. Laughter therapy was consisted of the delivery of information and active motion resulting in laughter. We provided laughter therapy 4 times for 2 weeks. Each session lasted 60 min. The experimental group received laughter therapy intervention as a group. An average attendance frequency per person was 2.7. To evaluate the effect of laughter therapy, the degrees of depression and anxiety were measured by Hospital Anxiety and Depression (HAD) and stress was measured by the Brief Encounter Psychosocial Instrument (BEPSI). Data analysis included a 2-test, t-test, and Fisher's exact test using SPSS 12.0 and SAS 8.0. Results: There was significant decrease in the degrees of depression, anxiety, and stress in the experimental group compared to those in the control group (p<.01, p=.04, and p<.01, respectively). Conclusion: This study provides evidence that laughter therapy is an effective intervention in improving depression, anxiety, and stress in breast cancer patients.

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University Linkages in Technology Clusters of Emerging Economies - Exploratory Case Studies from Cyberjaya, Malaysia - a Greenfield Development and Cyberabad, India - a Brownfield Development

  • Mohan, Avvari V.;Ejnavarzala, Haribabu;Lakshmi, C.N.
    • World Technopolis Review
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    • 제1권1호
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    • pp.42-55
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    • 2012
  • This paper is concerned with the linkages between universities and industry in the information and communications technology (ICT) in Cyberjaya, Malaysia and Cyberabad, India. In the case of the ICT cluster of Cyberjaya, the context can be termed as greenfield cluster development as the whole project is developed from scratch. In the case of Cyberabad, India, the context can be seen as a brownfield development, where the cluster developed based on existing and new organisations in a region. There is extant literature in research, be it from an Innovation systems or a Triple Helix perspective that has given significant attention to the importance of universities as engines of growth and also about the significance of their linkages with industry innovation in regions. But as argued by scholars like Chaminade et al, most of these papers tend to ignore the specific context in which this interaction between the university and the industry takes place - this study aims to fill this gap through an exploratory study from emerging economies and in a greenfield and brownfield contexts. The findings from the two cases point towards (1) the role of intermediary organisations in developing the linkages, (2) the issue of capabilities of universities for supporting industry development and (3) university-industry linkages are different in greenfield and brown field developments. The paper presents the cases and discusses the findings and provides insights to cluster development officials and policy makers and implications to researchers for developing studies of university-industry from a capabilities and context perspectives.

Medical Body Area Networks(MBAN)에서 CSMA/TDMA를 이용한 긴급 메시지 전송 프로토콜 (Emergency Message Transmission Protocol using CSMA/TDMA in Medical Body Area Networks(MBANs))

  • 김경준
    • 한국항행학회논문지
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    • 제13권2호
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    • pp.224-230
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    • 2009
  • 최근, Medical Body Area Networks (MBAN)는 사람의 인체를 진단하기 위한 새로운 기술로서 주목받고 있다. MBAN은 소형, 저 전력, 단거리 무선통신 기술을 의료(medical)분야에 적용한 의료 네트워크 이다. 본 논문은 MBAN에서 긴급 메시지 전송시 패킷 간 충돌과 IEEE 802.15.3이 가지는 전송대기 시간에 의해 발생하는 전송지연을 개선하기 위해 Carrier Sense Multiple Access/Time Division Multiple Access를 이용한 프로토콜을 제안하였다. 제안하는 프로토콜은 전력의 효율성 및 신뢰성을 개선하기 위해, IEEE 802.15.3의 MCTA를 MBAN에서 적용 가능한 SR-MCTA로 변형하여 전송의 신뢰성 및 전력 사용의 효율성을 높였다. 제안하는 프로토콜에서 SR-MCTA 슬롯은 단말 디바이스의 요청에 의해 MBAN 코디네이터가 할당하며, 할당하는 방법은 현재 슬롯에서 긴급 패킷이 발생할 때 임의의 충돌 패킷을 발생시켜 패킷을 획득하는 방법을 사용한다. 제안하는 프로토콜의 성능을 평가하기 위해 전송대기 시간을 평가할 수 있는 수식을 유도하고, 또한 이러한 결과를 이용하여 시뮬레이션 하였다. 시뮬레이션의 결과는 우리가 제안하는 프로토콜에서는 전송지연이 개선됨을 보였다.

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The Effect of Hierarchy Culture on Clan Leadership and Organizational Commitment of Export-Driven SMEs

  • KIM, Hyuk Young
    • 산경연구논집
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    • 제11권4호
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    • pp.19-30
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    • 2020
  • Purpose: The purpose of this study examines the mediating effect of clan leadership in the relationship between hierarchy culture and organizational commitment. Most previous research focused on the relationship between organizational culture and organizational performance or organizational culture and job satisfaction. There are few empirical studies that focus on organizational commitment data because it is difficult to collect in many cases of export-driven small and medium sized enterprises. However, this research measures affective commitment, continuance commitment, and normative commitment differently than previous research, which is mostly focused on the hierarchy culture, clan leadership, and organizational commitment measurements. Research design, data, methodology: Conceptual research model is based on the studies of Cameron and Quinn (2011), and Gungor and Sahin (2018). The model is designed with three constructs such as hierarchy culture, organizational commitment, and clan leadership. The monitor culture and coordinator culture are as proxy for the hierarchy culture. The affective commitment, continuance commitment, and normative commitment are as proxy for the organizational commitment. And also the facilitator leadership and mentor leadership are as proxy for the clan leadership. Based on three hundred cases such as export-driven small and medium sized enterprises (SMEs), this study verify the hypothesis. Hypothesis was analyzed with the structural equation modeling. Results: In case of export-driven small and medium sized enterprises (SMEs), clan leadership acts as a mediator in the relationship between hierarchy culture and organizational commitment. In case of export-driven small and medium sized enterprises (SMEs) with high organizational commitment, clan leadership acts as a mediator in the relationship between hierarchy culture and organizational commitment. In case of export-driven small and medium sized enterprises (SMEs) with low organizational commitment, clan leadership did not act as a mediator in the relationship between hierarchy culture and organizational commitment. Conclusions: By controlling for the mediating effect of clan culture, this study have improved the academic contributions as well as policy and practical implications through empirical study of clan leadership that affect organizational commitment in the fields of hierarchy culture. In addition, this study means that the mediating effects on the variables of clan leadership were examined.

EU Water Framework Directive-River Basin Management Planning in Ireland

  • Earle, R.;Almeida, G.
    • Environmental Engineering Research
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    • 제15권2호
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    • pp.105-109
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    • 2010
  • The European Union (EU) Water Framework Directive (WFD) (2000/60/EC) was transposed into Irish law by Statutory Instrument Nos. 722 of 2003, 413 of 2005 and 218 of 2009, which set out a new strategy and process to protect and enhance Ireland's water resources and water-dependent ecosystems. The Directive requires a novel, holistic, integrated, and iterative process to address Ireland's natural waters based on a series of six-year planning cycles. Key success factors in implementing the Directive include an in-depth and balanced treatment of the ecological, economic, institutional and cultural aspects of river basin management planning. Introducing this visionary discipline for the management of sustainable water resources requires a solemn commitment to a new mindset and an overarching monitoring and management regime which hitherto has never been attempted in Ireland. The WFD must be implemented in conjunction with a myriad of complimentary directives and associated legislation, addressing such key related topics as flood/drought management, biodiversity protection, land use planning, and water/wastewater and diffuse pollution engineering and regulation. The critical steps identified for river basin management planning under the WFD include: 1) characterization and classification of water bodies (i.e., how healthy are Irish waters?), 2) definition of significant water pressures (e.g., agriculture, forestry, septic tanks), 3) enhancement of measures for designated protected areas, 4) establishment of objectives for all surface and ground waters, and 5) integrating these critical steps into a comprehensive and coherent river basin management plan and associated programme of measures. A parallel WFD implementation programme critically depends on an effective environmental management system (EMS) approach with a plan-do-check-act cycle applied to each of the evolving six-year plans. The proactive involvement of stakeholders and the general public is a key element of this EMS approach.

IEEE 802.15.3 Wireless PAN의 MAC에서 다중채널의 적용 (MAC Enhancement by Utilizing Multiple Channels in IEEE 802.15.3 High-Rate Wireless Personal Area Networks)

  • 이병주;이승형;최웅철;정광수;이장연;조진웅
    • 한국통신학회논문지
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    • 제30권8A호
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    • pp.656-663
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    • 2005
  • 본 논문에서는 IEEE 802.15.3 High-Rate WPAN (Wireless Personal Area Network) 환경에서 다중 채널을 사용하여 향상된 성능의 MAC 프로토콜을 제안한다. IEEE 802.15.3 High-Rate WPAN은 10m 내외의 거리에서 실시간 비디오 및 대용량 파일 전송을 목적으로 설계된 MAC과 PHY의 표준을 말한다. 현재 표준의 MAC 프로토콜은 하나의 무선 채널을 piconet 내의 모든 DEV가 공유하여 사용한다. 이 중 PNC(Piconet Coordinator)는 TDMA(Time Division Multiple Access)방식으로 DEV들에게 채널타임을 할당한다. 이런 경우 piconet내의 통신하는 DEV의 수가 많아지게 되면 superframe의 길이가 길어져 전송되는 데이터의 aggregate throughput이 떨어지고 QoS(Quality of Service)를 보장하지 못한다. 본 논문에서 하나의 piconet이 여러 개의 채널을 동시에 사용하여 aggregate throughput을 향상시키고 QoS를 보장하는 다중채널 MAC 프로토콜을 제안하고 시뮬레이션을 통해 향상된 성능을 증명한다.