• Proceedings of the Acoustical Society of Korea Conference
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• autumn
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• pp.179-182
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• 2000

본 논문은 전화음성 서비스 시스템의 핵심 기술인 멀티채널 음성인식 시스템의 구현에 대해서 기술하고자 한다. 구현한 시스템은 전화망 인터페이스 모듈, 음성입력 모듈, 음성인식 모듈, 및 서비스 제어모듈로 구성되어 있다. 전화망 인터페이스 모듈은 전화망을 이용한 교환기와의 호 처리 및 이벤트 처리를 담당하며, 전화망 접속카드와 밀접한 관계를 가지고 있다. 음성입력 및 인식 모들은 호 접속이 이루어진 채널로부터 음성을 입력받아 단어인식 기능을 수행하는 부분으로서 멀티 채널을 수용할 수 있는 구조로 설계되어 있다. 음성인식 모델은 문맥 종속형 CHMM 모델이며, 각각의 HMM 모델은 3-state, skip path 로 구성되어 있다. 음성인식 모듈내의 함수들은 모두 re-entrant 하도록 구성함으로써 멀티 채별이 가능하며, 각각의 채널은 모두 독립적인 메모리 공간에서 동작하도록 되어있다. 이와 같은 멀티채널 전화음성인식 시스템은 Dialogic보드를 이용하여 Windows NT에서 동작하도록 구현하였다. 실험결과, 구현된 시스템은 실시간으로 상용서비스가 가능한 인식율을 보였으며 원활한 멀티채널 지원이 가능하였다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2023.11a
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• pp.182-184
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• 2023

'스마트 항로표지 현장시설 고도화 연구'를 통해 다양한 센서를 통해 해상 데이터를 수집하고, 이를 가공하여 선박과 육상 연계시스템에 전파하는 방안이 논의되고 있다. 본 논문에서는 특정 업체에 종속되지 않고 미래 기술 발전에 유연한 대응이 가능하도록 스마트 항로표지 인터페이스 플랫폼에 대한 기술 요구사항의 표준화 방안을 정리한다. 이미 정의된 표준 구문은 그대로 수용하고, 신규 센서의 경우 관련 구문을 새로 정의하여 표준화하며 장치들을 직집 연결하거나 망 접속을 통해 연결하기 위해 정의되어야 하는 사안들을 정리한다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.4
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• pp.1789-1796
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• 2012

In this paper, a new high-efficiency CMOS bridge rectifier for driving RFID tag chips is designed and analyzed. The input stage of the proposed rectifier is designed as a cascade structure connected with two NMOSs for reducing the gate capacitance by circuitry method, which is the main path of the leakage current that is increased when the operating frequency is increased. This gate capacitance reduction technique using the cascade input stage for reducing the gate leakage current is presented theoretically. The output characteristics of the proposed rectifier are derived analytically using its high frequency small-signal equivalent circuit. For the general load resistance of $50K{\Omega}$, the proposed rectifier shows better power conversion efficiencies of 28.9% for 915MHz UHF (for ISO 18000 -6) and 15.3% for 2.45GHz microwave (for ISO 18000-4) than those of 26.3% and 26.8% for 915MHz, and 13.2% and 12.6% for 2.45GHz of compared other two existing rectifiers. Therefore, the proposed rectifier may be used as a general purpose rectifier to drive tag chips for various RFID systems.

• Journal of Korea Multimedia Society
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• v.2 no.1
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• pp.47-58
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• 1999

In this paper, we design the radio interface protocols of wideband Wireless Local Loop(WLL) that uses wideband Code Division Multiple Access(CDMA), and propose the random access procedures on access channel and analyze the performance of the channel. The structure of radio interface protocols are designed by three modular parts to meet the requirements of IMT-2000 : radio resource controlling part that depends on the radio resources, connection controlling part that is independent of the radio resources, and application part that supports the interface between different parts and user terminals. In addition, we propose the random access procedures on access channel and analyze the performance of the channel. We assume that both near-far effect and shadow fading can be compensated by open loop power control. We observe that the number of access probes(delay) depend on the initial mobile transmission power and power increment, and the poor estimation of initial mobile transmission power might increase the average number of access probes.

• 한국IT서비스학회:학술대회논문집
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• 2009.05a
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• pp.397-400
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• 2009

현재 웹은 단순히 정보를 수집하여 제공하던 웹 1.0을 지나 정보의 사용자가 곧 생산자가 되어 개방된 웹 환경을 기반으로 사용자 스스로 콘텐츠를 제작, 재창조, 공유하는 인터넷 서비스 모델인 웹 2.0으로 발전하였다. 이러한 웹의 발전 과정에서 시맨틱 웹이 등장하게 되었고 시맨틱 웹이 지리 정보와 접목되어 시맨틱 지리 정보 시스템이 등장하게 되었다. 기존 지리 정보 시스템에서는 사용자들이 국한된 정보만을 제공받아 왔지만 웹이 발전하고 수많은 콘텐츠가 생성되면서 웹의 데이터를 지리 정보 시스템과 연결시켜서 사용자에게 풍부한 정보를 제공 할 수 있는 시스템이 연구, 개발되고 있다. 하지만 기존 연구들은 사용자가 시스템에 접속하여 비공간 정보를 입력해야 하는 특정 시스템에 종속적이라는 단점을 가지고 있어 시맨틱 웹에서 지향하는 풍부한 서비스 제공에 어려움을 격고 있다. 따라서 이 논문에서는 웹 자원을 정의된 지리정보 온톨로지(Geo-Ontology)의 인스턴스로 추가하여 지리 정보 시스템의 비공간 정보를 확장함으로써 특정 시스템에 종속적이지 않고 사용자에게 보다 풍부한 서비스를 제공하기 위한 모델을 제안하고 프로토타입을 구현한다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.11
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• pp.2100-2106
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• 2007

Multi-stage folding A/D converter circuit with $0.25{\mu}m$ N-well CMOS technology is designed. This A/D converter consists of a transconductance circuit, linear folder circuit and 1bit A/D converter circuit. In H-spice simulation results, linear folder circuits having high linearity can be obtained when the current mode is used instead of voltage mode. And in case of 6bit, the delay time is limited about 40ns. From this results, 6bit 25MSPS A/D converter circuit can be realized.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.6
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• pp.131-137
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• 2014

Service Oriented Architecture(SOA) is a flexible structure which does not affect other services even when a specific service is changed. It provides the platform with neutral interfaces independent of any others, where services are loosely coupled in a standard way. While ESB (Enterprise Service Bus) is a key technology for service-oriented architecture, few research and development for ESB has been done. In this paper, we designed and implemented the key components of ESB such as mediation service, message oriented middleware service, operation service, monitoring service, application connection service, and database connection service. The performance evaluation was done by measuring the message processing time for the number of messages with various sizes.

• The Journal of Korean Association of Computer Education
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• v.7 no.3
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• pp.35-43
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• 2004

Internet-based P2P computing with independent machines suffers from frequent disconnections and security threats caused by leaving, failure, network diversity, or anonymity of participated machines. Replication schemes of shared resources are used for solving these issues in many studies and implementations. We propose an operational replication scheme in P2P computing to share computing resources, and the scheme verifies the correctness of operation against faults and security threats. This verifications are carried out periodically on replicated and dependent working units without global message exchanges over the whole system. The verified working units are treated as checkpoints, and thus they could be put to practical use for fault-tolerance with rollback recovery.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.10
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• pp.1829-1834
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• 2008

An optical switch/modulator is designed and the light propagating characteristics is analyzed by the simplified BPM. The distinctive feature of the switch/modulator is that all the waveguide branches are designed to be single-mode. Principle of the device is based on the coupled mode theory in the Y-junction interconnecting waveguide. In spite of all the waveguides are designed to be single-mode, adjusting the interconnecting waveguide length of the device, the same characteristics as existing device up to date is obtainable. Numerical results show that the switching characteristics periodically depends on the interconnecting waveguide length with a spatial of about 150${\mu}m$ in the Ti:LiNbO3 step index waveguide. The concept of design would be utilized effectively in fabricating the monolithic high density of optical integrated circuit.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.2
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• pp.29-35
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• 2013

For the purpose of designing and applying optimum surge protection, one of the essential points is to take into account the energy coordination between cascaded surge protective devices(SPDs) and it is important to obtain an acceptable sharing of the energy stress between two cascaded SPDs. In this paper, in case of two voltage-limiting SPDs connected in parallel, the amount of splitting impulse current and energy that flow through each SPDs is investigated as a function of the protective distance. As a result, the energetic coordination between cascaded SPDs is strongly dependent on the voltage protection level of SPDs and the protective distance. It was confirmed that the sharing of the energy between two cascaded SPDs and the limited voltage levels are appropriate when the voltage protection levels of both upstream and downstream SPDs are the same.