• Title/Summary/Keyword: DAS System

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Downlink Capacity Analysis of Distributed Antenna Systems with Imperfect Channel State Information

  • Xu, Weiye;Lin, Min
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.11 no.1
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    • pp.253-271
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    • 2017
  • In this paper, considering that perfect channel state information (CSI) is hard to achieve in practice, the downlink capacity of distributed antenna systems (DAS) with imperfect CSI and multiple receive antennas is investigated over composite Rayleigh fading channel. According to the performance analysis, using the numerical calculation, the probability density function (PDF) of the effective output SNR is derived. With this PDF, accurate closed-form expressions of ergodic capacity and outage probability of DAS with imperfect CSI are, respectively, obtained, and they include the ones under perfect CSI as special cases. Besides, the outage capacity of DAS in the presence of imperfect CSI is also derived, and a Newton's method based practical iterative algorithm is proposed to find the accurate outage capacity. By utilizing the Gaussian distribution approximation, another approximate closed-form expression of outage capacity is also derived, and it may simplify the calculation of accurate outage capacity. These theoretical expressions can provide good performance evaluation for downlink DAS for both perfect and imperfect CSI. Simulation results verify the effectiveness of the theoretical analysis, and the system capacity can be improved by increasing the receive antennas, and decreasing the estimation error or path loss. Moreover, the system can tolerate the estimation error variance up to about 0.01 with a slight degradation in the capacity.

Distributed Antenna System for Intra-vehicle Wireless Energy Transfer (차량 내 무선 에너지 전송을 위한 분산 안테나 시스템)

  • Kim, Yeonghwan;Kwon, Kuhyung;Lee, Chungyong
    • Journal of the Institute of Electronics and Information Engineers
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    • v.54 no.2
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    • pp.3-8
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    • 2017
  • This paper considers an application of distributed antenna system (DAS) to a system of intra-vehicle wireless energy transfer (WET). The intra-vehicle WET system has features such as limited mobility of energy receiver, static channel environment and short distance between transmitter and human body. Under these conditions, location of transmitter highly affects the amount of energy received by human body and the energy received by energy receiving devices. We compare centralized antenna system (CAS) and the DAS in intra-vehicle WET system by simulation. The results show the DAS has superior performance to the CAS.

The Development of An Improved Distribution Automation System Including Low Voltage Monitoring Function (저압 배전망 감시기능을 포함하는 개선된 배전자동화시스템 개발)

  • Shin, Chang-Hoon
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.8 no.5
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    • pp.1034-1041
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    • 2007
  • This paper presents the developing results of improved distribution automation system including system configuration and subsystem design, prototype hardware and software implementation, and pilot tests on the real distribution networks of Korea Electric Power Corporation (KEPCO). An integrated system is designed to combine independent system for the distribution field works with DAS; transformer monitoring, power quality monitoring, voltage monitoring, outage monitoring, etc. The communication network is hierarchically configured as main network and branch network and well-defined integrated terminal units were developed. In addition, useful host configuration and applications were developed to integrate the services with DAS or interfacing other systems. Pilot tests were performed to verify that the system enables to properly integrate the DAS and other services of the distribution network.

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Design and Implementation of Mobile Crowdsourcing-based Driver Assistance Systems (MC-DAS) (모바일 크라우드소싱 기반 운전자 지원 시스템의 설계 및 구현)

  • Jeong, Han-You
    • Journal of IKEEE
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    • v.22 no.1
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    • pp.29-37
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    • 2018
  • In recent years, there have been increasing interests in the mobile crowdsourcing that exploits multiple sensors, communication and user interfaces, and the computation power of widespread smartphones. In this paper, we present a novel mobile crowdsourcing-based driver assistance systems (MC-DAS) that crowdsource the sensor data of smartphone app having already passed a road segment, generate its profile information through a massive data processing, and forward this profile to the smartphone app of vehicle entering the road segment. Based on the MC-DAS platform, we also design and implement a new navigation system that advices the vehicle speed depending on the speedbump and on the road curvature profile. We expect that the proposed MC-DAS platform will be used as a platform for emerging new mobile crowdsourcing applications.

Eine methodische Betrachtung fur die Erstellung des koreanisch-deutschen WordNets (한독 워드넷 구축을 위한 기본 방법론 고찰)

  • Nam Yu-Sun
    • Koreanishche Zeitschrift fur Deutsche Sprachwissenschaft
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    • v.9
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    • pp.217-236
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    • 2004
  • Das Ziel dieser Arbeit ist es, als eine methodische Grundlage zur Erstellung des koreanisch-deutschen WordNets das Grundwissen $\"{u}ber$ das WordNet und einige bisherige Untersuchungen des WordNets darzulegen. Ais erster Schritt wurde einige grundlegende Punkte $f\"{u}r$ das WordNet im Rahmen des WordNets fur Englisch in Betracht gebracht. Dabei ging es um lexikalische Hierarchie, und um semantische Relationen zwischen den Synsets(Zusammensetzen der synonymen $W\"{o}rter$) wie Synonymy, Antonymy, Hyponymy, Mronymy, Troponomy und Entailment. $Anschlie{\ss}end$ wurden EuroNet und GermaNet in kurzer Form vorgestellt, die auf dem Princeton WordNet basierten. EuroNet ist eine multilinguale Datenbasis mit WordNets $f\"{u}r$ einige europaische Sprachen (hollandisch, italienisch, spanisch, deutsch, franzasisch, tschechisch und estnisch). Dieses auf das Deutsch bezogenen WordNet kann wichtige Hinweise $f\"{u}r$ die Erstellung des koreanisch-deutschen WordNets geben. In Korea wurden auch verschiedene Untersuchungen uber das WordNet $f\"{u}r$ Koreanisch unternommen. Darunter kann insbesondere KORTERM WordNet $f\"f{u}r$ Koreanisch als ein umfassendes System $erw\"{a}hnt$ werden, in dem Nomen, Verben, Adjektive und Adverbien miteinander interagieren. KORTERM WordNet fur Koreanisch ist eine multilinguale Datenbasis mit WordNets $f\"{u}r$ einige asiatische Sprachen (koreanisch, japanisch und chinesisch) und versucht noch die weiteren Sprachen in diese multilinguale Datenbasis hineinzubringen. Nach diesem WordNet wird das koreanisch-deutsche WordNet erstellt.

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Development target of intelligent DAS with the function of distribution transformer monitoring (배전변압기 감시제어 기능이 통합된 지능형 배전자동화 시스템 개발 방향)

  • Ha, Bok-Nam;Seol, Lee-Ho;Park, Shin-Yeol;Jeong, Yeong-Beom
    • Proceedings of the KIEE Conference
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    • 2005.07a
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    • pp.554-556
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    • 2005
  • Distribution Automation System (DAS) will provide supervision and remote control of switches and reclosers such as pole pounted switches and pad-mounted switchgears on high voltage distribution line. Kepco had developed basic function such as remote monitoring, remote control, remote measuring and remote setting at first. As a next step, Kepco has been developed diverse application programs such as single line diagram drawing program, relay coordination program, feeder reconfiguration program, over load elimination program, bad data detection program, section load management program, fault processing program and so on. Kepco is examining to develop more powerful functions for special specification of foreign distribution automation system. This paper explains what is the target for overseas DAS market.

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The Database Structure of Integrated Gateway System for Wireless-Internet Service in W-CDMA (비동기식 IMT-2000에서 무선 인터넷 접속을 위한 통합 게이트웨이 시스템의 데이터베이스 구성)

  • Lee, Hoon-Ki;Ryu, Won
    • Proceedings of the Korea Information Processing Society Conference
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    • 2003.11b
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    • pp.1029-1032
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    • 2003
  • 본 논문은 무선 인터넷 서비스를 제공하는 이동통신 망에서 동기식과 비동기식 IMT-2000서비스를 동시에 제공하는 통합 게이트웨이 시스템인 A-MiDAS(Advanced Mobile internet Data Access System)을 위한 데이터베이스 구성 방법에 관한 것이다. A-MiDAS시스템은 동기식 망의 PDSN 노드 역할과 비동기식 망에서의 GGSN 게이트웨이를 담당한다. 패킷에 대한 사용자 인스턴스로서의 세션 정보는 사용자가 패킷 통신을 하고자 할때, 시작부터 종료 시까지의 모든 과정에서 발생하는 유지 정보를 관리하여 각각의 인스턴스 항목간의 오버헤드를 줄이고 세션 정보의 관리를 용이하고, 검색에 따른 지연시간을 줄일 수 있어야 한다. 또한 전체 시스템의 상태를 관리함으로써 운용상에서 실시간 모니터링을 통한 사용자의 인터넷 서비스를 안정적이고 지속적으로 제공할 수 있다. 이에 본 논문에서는 GPRS망에서의 GGSN을 담당하는 게이트웨이 시스템 관점에서의 A-MiDAS시스템을 구축하는데 필요한 데이터베이스 구성 방법을 제시한다.

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The Development of a Distribution Automation System with an Wireless Network (무선통신망을 이용한 배전자동화시스템 개발 연구)

  • Kim, Myong-Soo;Hyun, Duck-Hwa
    • Proceedings of the KIEE Conference
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    • 2000.07d
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    • pp.2747-2749
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    • 2000
  • The KEPRI has been developing the medium/small scale Distribution Automation System(DAS) that adopts wireless transmission media for exchanging information between master and remote terminals. It was concluded that Short Message Service(SMS) of Personal Communication Service(PCS) was the best wireless transmission media for the medium/small scale DAS in the last year. However. we had problem that PCS had long transmission delay. Therefore. SMS phones will be substituted with Radio Link Protocol(RLP) modems having transmission delay less than 5 seconds. This paper describes wireless networks for DAS, practical experience.

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Implementation of DAS for Bio information Measuring (생체정보측정기와 연계된 DAS(Data Acquisition System) 설계)

  • Hong, Sung-Woong;Kim, Youn-Seo;Kim, Pyeong-Jung
    • Proceedings of the Korea Information Processing Society Conference
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    • 2009.11a
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    • pp.27-28
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    • 2009
  • 본 논문에서는 사용자자동인식, 실시간 상태 모니터링에 적합한 유헬스 시스템을 위한 생체정보측정기와 연계된 임베디드 미들웨어 DAS(Data Acquisition System)를 제안한다. DAS는 U-health 서비스를 제공하기 위해 센서정보와 정보처리기 중간에서 센싱 정보수집기의 불필요한 요소를 제거하고 HMS의 통신기능을 담당하는 기능을 갖는다.

Machine Learning-based Phase Picking Algorithm of P and S Waves for Distributed Acoustic Sensing Data (분포형 광섬유 센서 자료 적용을 위한 기계학습 기반 P, S파 위상 발췌 알고리즘 개발)

  • Yonggyu, Choi;Youngseok, Song;Soon Jee, Seol;Joongmoo, Byun
    • Geophysics and Geophysical Exploration
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    • v.25 no.4
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    • pp.177-188
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    • 2022
  • Recently, the application of distributed acoustic sensors (DAS), which can replace geophones and seismometers, has significantly increased along with interest in micro-seismic monitoring technique, which is one of the CO2 storage monitoring techniques. A significant amount of temporally and spatially continuous data is recorded in a DAS monitoring system, thereby necessitating fast and accurate data processing techniques. Because event detection and seismic phase picking are the most basic data processing techniques, they should be performed on all data. In this study, a machine learning-based P, S wave phase picking algorithm was developed to compensate for the limitations of conventional phase picking algorithms, and it was modified using a transfer learning technique for the application of DAS data consisting of a single component with a low signal-to-noise ratio. Our model was constructed by modifying the convolution-based EQTransformer, which performs well in phase picking, to the ResUNet structure. Not only the global earthquake dataset, STEAD but also the augmented dataset was used as training datasets to enhance the prediction performance on the unseen characteristics of the target dataset. The performance of the developed algorithm was verified using K-net and KiK-net data with characteristics different from the training data. Additionally, after modifying the trained model to suit DAS data using the transfer learning technique, the performance was verified by applying it to the DAS field data measured in the Pohang Janggi basin.