• 전기저널
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• 통권403호
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• pp.73-73
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• 2010

• 전자공학회논문지S
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• 제35S권4호
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• pp.30-39
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• 1998

Currently, LAMA(Local Automatic Message Accounting) is a billing mechanism which is being used for billing process, in which billing dat is written on MT(Magnetic Tape), collected at each regional billing center and then processed once a month. However, in order to prepare further development of telecommunication network and future new services, computerization of billing process and new daily billing processing system are urgently needed. Therefore Korea Telecom had developed a CAMA (Centralized Automatic Message Accounting) system for M10CN switch. In the CAMA system, billing data generated in switches is transfered on-line using approproate protocols and various transmission media and immediately processed. The CAMA system for M10CN switch consists of three parts such as ED (Extraction Device), TD(Transmission Device) and HC(Host Collector). The system also has redundancy to maintain continuance and confidence of system operation.

• 조명전기설비학회논문지
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• 제29권11호
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• pp.47-52
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• 2015

This paper derives the problems that occur when asynchronous transfer in case of phase, frequency, voltage between the emergency generator and the grid and proposed the countermeasure to solve this problem when the transfer switch replace ATS(Automatic Transfer Switch) with CTTS(Closed Transition Transfer Switch) for the non-interrupting switching. In order to simulate above cases, modelling was used the transient analysis program PSCAD/EMTDC. By using this, the customer installed emergency generator and the grid was implemented. We compared three cases of asynchronous transition based on the basic case and proposed improvement by controlling the governor of emergency generator.

• 조명전기설비학회논문지
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• 제22권10호
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• pp.34-40
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• 2008

본 논문에서는 최근 증가 일로에 있는 자동점멸식 보안등에 대한 안전점검 방안을 제시하였다. 기술적인 측면으로서 보안등주의 하부에 안전점검을 위한 별도의 점검함을 설치하고 점검원이 누설전류, 누전차단기의 정상적인 동작 상태, 절연저항 및 접지저항을 승주하지 않고 측정할 수 있도록 하였으며, 충전부에 대한 직접 접촉의 가능성을 최대한으로 경감함으로써 감전의 위험으로부터 자유로울 수 있도록 설계하였다. 본 연구의 결과물을 실용화함으로써 보안등에 대한 점검을 최대한 안전하고 효율적으로 수행하는데 일조할 수 있을 것으로 기대한다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 추계학술대회 논문집
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• pp.794-797
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• 2005

The automatic load transfer switch (ALTS), a kind of electric power switch, typically automatically transfers electrical loads from a normal electrical power source to an emergency electrical power source upon reduction or loss of normal power source voltage. It can also automatically re-transfer the load to the normal power source when the normal voltage has been restored within acceptable limits. The transfer operation of ALTS is accomplished by a spring-driven linkage mechanism. In order to control or delay the transfer switching time, the ALTS studied in this paper uses the superposed leaf springs, which are subjected to impact leadings in contacting with electrical contacts. Therefore, to confirm whether the springs has enough mechanical endurance in ALTS, we build a finite element model of the superposed lear springs using LS-DYNA and perform the impact and fatigue analysis.

• 한국정보통신학회논문지
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• 제19권6호
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• pp.1443-1448
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• 2015

현재 대부분의 지하공동구 출입관리시스템은 중앙시스템과 자동개폐기 간 네트워크가 유선 상으로 구축되어 있으며, 네트워크 인프라의 부재 그리고 리더기의 야외 노출 등 지하공동구의 특수한 환경에서의 문제점들이 노출되어 있다. 이에 본 논문에서는 지하공동구의 출입관리에 대한 문제점들을 파악하고 이를 해결하기 위해 지하공동구의 특수 환경에 적합하며, 체계적인 출입 및 점검 이력의 관리가 가능한 스마트 폰 인증키 기반 지하공동구 출입관리시스템을 제안한다. 제안한 출입관리시스템은 현장 네트워크의 별도 통신망 구축 없이 스마트폰에서 지원하는 블루투스를 사용하여 출입이 가능하며 아울러, 모든 개폐기의 제어 정보를 스마트폰 애플리케이션을 통하여 서버로 전송하여 서버에서의 체계적인 통제 및 이력관리가 가능하다.

• 한국컴퓨터정보학회지
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• 제2권1호
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• pp.35-44
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• 1995

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.3180-3186
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• 2011

A segmented scissors type switch has been developed for the urban transit maglev demonstration line to be commercialized near Incheon International Airport in 2013. Based on the design of the previous segmented 3-way switch, the scissors switch is composed of four segmented 2-way switches up/down and left/right and a turn table in the mid point. The main function of the scissors switch is to change the running direction of the train at end terminals. The developed scissors switch is planned to be installed in front of the 102 station, which has a side platform, of the demonstration line. The total length of the switch is 65m and the distance between the up and down track centerlines is 6m. The 2-way switches and turn table are made of steel box type beams, and have their own driving unit, locking unit, control unit, levitation and propulsion rails, and so on. Installed in the factory, a 100,000-cycle continuous operation test was carried out after manual and automatic test operations. The applicapability of the developed switch was verified through the measurements of the linearity of the track after repetitive operations, the mechanical operation noise, the load of the main driving motor, the safety of the control panel, the natural frequency of the girder, the deformation of the girder, and so on.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권11호
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• pp.5223-5242
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• 2017

In the last decade, the 2.4 GHz band of IEEE 802.11 WLANs has become heavily congested due to the explosive increase in demand of Wi-Fi connectivity. With the current deployment of enterprise WLANs, channel switching mechanism continues to exhibit inefficiencies because it cannot adapt to real-time channel condition and the inability to support seamless channel switching. Software Defined Networking (SDN) as an emerging architecture is promising to introduce flexibility and programmability for wireless network management. Leveraging SDN to existing enterprise WLANs, channel switching method can be improved significantly. This paper presents a software-defined enterprise WLAN framework with a load aware automatic channel switching solution, which utilizes AP load and channel interference factor (CIF) to provide seamless channel switching. Two automatic channel switching algorithms named Single Switch (SS) and Double Switch (DS) are proposed to improve the overall user experience and the experience of users with highest traffic load respectively. Experiment results demonstrate that our solution can efficiently improve user experience in terms of jitter, transmission delay and network throughout when compared to the conventional channel switching mechanism.

• 한국초전도ㆍ저온공학회논문지
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• 제7권1호
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• pp.21-24
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• 2005

The problem of fluctuation-induced digital errors in a rapid single flux quantum (RSFQ) circuit has been very important issue. So in this experiment, we calculated error rate of RSFQ switch in superconductiyity ALU, The RSFQ switch should have a very low error rate in the optimal bias. We prepared two circuits Placed in parallel. One was a 10 Josephson transmission lines (JTLs) connected in series, and the other was the same circuit but with an RSFQ switch placed in the middle of the 10 JTLs. We used a splitter to feed the same input signal to the both circuits. The outputs of the two circuits were compared with an RSFQ XOR to measure the error rate of the RSFQ switch. By using a computerized bit error rate test setup, we measured the bit error rate of 2.18$\times$$10^{12}$ when the bias to the RSFQ switch was 0.398mh that was quite off from the optimum bias of 0.6mA.