• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.05a
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• pp.226-230
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• 2003

In this thesis I analyzed that V5.2 protocol function is effective to fulfill all of the services that are provided at the existing local exchange. I analyzed this in five methods that refer to ETSI inside patronage. I experimented turnaround time by Start-up method and verified V5.2 protocol function when Start-up. Also I confirmed stability of system by the reconstruction-ability experiment related E1 switch over. I verified V5.2 protocol function through PSTN call process that uses a special service test and local call simulator. As a result of experiment, I confirmed the best method when simultaneous Start-up. V5.2 protocol function was excellent and It becomes switch over at 1/1000 seconds when E1 is out of service. V5.2 protocol function was effective to fulfill all of the special services that are provided at local exchange and its long call process ability was superior to KT standard with 4 fails in 20000 calls. Through the experiment, it was proved that V5.2 interface will become a significant element of communication network when after LE side expanse of v5 interface ID with TDX-100 exchanger and the AN occurrences OOS by message transmission limit and call disconnect when E1 switch over are improved.

• Journal of the Korea Institute of Military Science and Technology
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• v.11 no.5
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• pp.5-11
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• 2008

Recently developed radars use the solid-state power amplifier to amplify the RF signal. The stability of RF signal directly depends on that of the electric power. So the stable and reliable electric power should be needed. When the electric power switch is tuned on for the first time in order to operate the radar system, the in-rush current is generated because of the capacitive characteristic. The excess in-rush current breaks the element. Therefore, the analysis about the in-rush current to design the electric power system is necessary. In this paper, modeling and simulation on the whole power system is carried out and the necessity of limiting the in-rush current is verified. After the analysis, the circuit to limit the in-rush current is designed and examined to verify the analysis. The circuit is good enough to limit the in-rush current.

• Journal of Convergence for Information Technology
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• v.9 no.9
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• pp.38-43
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• 2019

In this paper, a method of inputting one analog input and two digital switch inputs by using one analog port of microcontroller embedded in IoT device was proposed. In this method, the upper limit and the lower limit of the input voltage range of the analog input port are determined, and the analog input voltage is input to this interval. The digital switches are configured to exceed the boundaries of the upper and lower limits, respectively. To verify the performance of the proposed method, an experimental circuit was constructed and tested using a microcontroller. As a result, all three inputs can be sensed using a single analog port, thus confirming that the three required input ports are reduced to one input port, ie, 33%.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.7
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• pp.791-796
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• 2012

A RF limiter is a component to protect the receiver front end from undesired signal. A RF limiter is a key component whose output is constant level for all inputs above a critical value. A RF limiter use a diode to pass signals of low power while attenuating those above some threshold. A RF limiter for receiver protection in modern radar systems is playing a vital role in order to meet challenges of new interference threats and complicated electromagnetic environments. This paper proposed a new circuit for high power RF limiter whose structure is the combination of the PIN diode and Limit diode. PIN diode take a use of its isolation characteristics which act as a switch does. A 2 kW RF limiter with 200 us pulse width at S-band was developed. It shows good agreements between estimated value and measured results.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.2B
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• pp.100-107
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• 2007

Recently, a study of BcN(Broadband convergence Network) is progressing continuously, and it is important to improve the quality of the service according to subscribers because a scale of network is about to be larger. It is more important to manage QoS(Quality of Service) of all subscribers in layer 2 than layer 3 network since managing it in layer 3 network cost both additional processes and large hardware. Moreover, QoS based on Best-Effort service has been developed because tots of subscribers should use limited resource in BcN. However, they want to be supplied with different service even though they pay more charge. Therefore, it is essential to assign the different bandwidth to subscribers depending on their level of charge. The method of current Rate Limiter limits the bandwidth of each port that does not offer fair service to subscribers. The Rate Limiter proposed in this paper limits bandwidth according to each subscriber. Therefore, subscribers can get fair service regardless of switch structure. This new Rate Limiter controls the bandwidth of subscribers according to the information of learning subscriber and manages maximum performance of Ethernet switch and QoS.

• Journal of Korea Multimedia Society
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• v.19 no.2
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• pp.405-410
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• 2016

Elevator industry is a field that is mechanical, electrical and electronic technology and constantly requires inspection and maintenance considering various applications and various types. Recently, various elevator control and monitoring technologies with IT are developing for elevators on land. But technologies with IT have been hardly done in marine elevator that is consistently assured safety and reliability of life cycle for its parts in poor environment. In this paper, we implemented embedded main controller, floor controller and car controller that meet the requirements and use NMEA network protocol by analyzing home and abroad integrated elevator operation and management systems. Especially, we secured reliability of maintenance by real-time fault diagnosis and control that was implemented with limit switch, gyro sensor, temperature/humidity/barometric pressure sensor and fire detection sensor thinking over the environmental conditions of terrestrial and marine elevator.

• Proceedings of the Korean Nuclear Society Conference
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• 1997.05a
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• pp.207-212
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• 1997

영광2호기에 설치되어있는 노내 중성자속 감시 계통 설비인 기계식 인출제한 스위치(Withdrawl Limit Switch)의 구조적인 결함을 제거하기 위한 원인 분석 및 개선과정에 중점을 두었다. 기계제어방식의 구조적 결함은 검출기(Detector)가 노심의 중성자속(Neutron Flux)을 측정하기 위해 구동기의 수동 혹은 자동운전시 검출기 안내관에 삽입 인출이 반복 수행되면서 물리적 또는 환경적요인에 의한 레버의 휘어짐으로 접촉위치의 변경이 발생하는 것을 의미한다. 콘솔내 다수의 마이크로-프로세서(Multiple-Microprocessors)에 의한 구동기(Drive Unit) 동작으로 노심내 3차원 중성자속 분포를 측정할 수 있는 유일할 설비로써 본 계통은 그동안 관련 보수작업 및 설비개선에도 불구하고 근본문제점이 해소되지 못한 가운데 여러차례의 설계, 모의시험을 거쳐 인출제한스위치 제어 방식을 기계식에서 전자식으로 개선, 대체하여 시험 및 운전해 본 결과 근본적 결함원인이 해결되었음을 확인하였다.

• Journal of Power Electronics
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• v.16 no.4
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• pp.1298-1305
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• 2016

This paper presents the development of a short-circuit protection mechanism on a high voltage switch (HVS) board which is built by a series connection of semiconductor switches. The HVS board is able to quickly detect and limit the peak fault current before the signal board triggers off a gate signal. Voltage clamping techniques are used to safely turn off the short-circuit current and to prevent overvoltage of the series-connected switches. The selection method of the main devices and the development of the HVS board are described in detail. Experimental results have demonstrated that the HVS board is capable of withstanding a short-circuit current at a rated voltage of 10kV without a di/dt slowing down inductor. The corresponding short-circuit current is restricted to 125 A within 100 ns and can safely turn off within 120 ns.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.10
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• pp.1832-1837
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• 2011

The fault current has increased due to the large power demand in power distribution system and network distribution system. To protect the power system effectively from the increased fault current, the superconducting fault current limiter (SFCL) has been notified. However, the conventional SFCL has some problems such as cost, operation, recovery, loss. To solve some problems, the hybrid superconducting fault current limiter using the fast switch was proposed. However, hybrid SFCL also has a problem that is protection coordination in power distribution system with hybrid SFCL. In this paper, the fault current limiting characteristics of hybrid SFCL with first half cycle non-limiting operation according to the fault angle, the resistance of superconducting element, and the magnitude of Current Limit Resistor (CLR) which are the components of hybrid SFCL were analyzed through the experiments.

• Journal of the Korean Graphic Arts Communication Society
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• v.14 no.1
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• pp.17-29
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• 1996

N-substituted acrylamide hydrogel is reported to have the feature of bing transparent and sensitive enough to response to a temperature stimulus below the temperature of phase transition. Especially at the near of 35 C it becomes shrunk and opaque very quickly. It has also the characteristic of reversing swelling and shrinking. The experiment showed that it is possible to produce a functional gel of super water absorption with the process of free radical polymerizing PVA(polyvinylalcohol) and PAA(polyacrylamide), and crosslinking. The ratio of shrinking and swelling caused by copolymerization rises 10% to 80% at the each temperature of 20 C, 30 C, 40 C, respectively. Phase transition temperature of this gel by copolymerization is50 C while that of ordinary N-substituted acrylamides is between 32~35 C. This temperature reaches the rearing limit of animals and plants so that volumetric transition polymer gel can be ulilized in varying fields such as agriculture/gardening which are water-using field, on-off switch sensing temperature and volumetric variation, processing of liquid wastes and civil engineering works, architecture and electronics. We have no doubt that this material will be the high-functional resin in the hi-tech age of the near future.