• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 1999.04a
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• pp.14-14
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• 1999

비활성 가스제너레이터는 가스터빈 추진기관 및 기타 열기관을 이용하여 연소가 되지 않는 저온의 공기를 생산하는 기계장치를 말하며 이러한 저온의 비활성 기체를 화재 지역에 분사하는 경우 기존의 소방수를 이용한 화재 진압방식보다 매우 효율적으로 화재진압에 사용되어 질 수 있다. 일반적으로 민항기 등의 가스터빈 추진 기관에서 배기되는 기체내에는 터빈입구온도(TIT : Turbine Inlet Temperature)및 초과공기지수(Excess Air Coefficient)에 따라 다르게 나타나지만 TIT가 1500$^{\circ}$K인 경우 약 13-14%정도의 산소가 잔존하는 것으로 알려져 있다. 따라서 본 연구에서는 가스터빈 및 열교환 시스템 그리고 터빈 1단 등의 시스템 조합율을 통하여 대기 중의 기체의 온도를 영하 2$0^{\circ}C$ 및 산소함유량을 약 5%수준까지 낮춤으로서 이를 대형 화재 진압에 사용하기 위한 연구이다. 비활성 가스제너레이터에 사용하는 연료로는 Kerosene 및 CNG(Compressed Natural Gas)등이 사용될 수 있으며, 유량이 8.1kg/sec인 터보축 가스터빈 엔진을 사용하는 경우 18750㎥ 부피의 비활성기체를 생산하는데 Kerosene 연료가 약 1톤(200＄ 이하)이 필요한 것으로 계산되며 이에 소요되는 시간도 약 52분에 지나지 않는 것으로 계산되었다. 만일 50kg/sec의 보다 큰 가스터빈 엔진을 사용하는 경우 약 9분 정도가 필요한 것으로 계산되었다. 사용되는 가스터빈은 압축비가 15, 열교환기의 효율이 $\varepsilon$=0. 그리고 최종 터빈 1단의 팽창비가 1.25가 적합한 것으로 계산된다. 연구 분석 결과 기술적 문제점으로는 배기 가스온도가 낮은데 따른 출구 부분의 Bearing, Sealing이 문제가 될 수 있다고 판단되며 배기 가스 자체에 대기 공기중에 함유되어 있던 습기가 얼어붙는(Icing화) 문제가 발생하기 때문에 배기가스의 Icing을 방지하기 위하여 압축기 끝단에서 공기를 추출하여 배기부분에 송출할 필요성이 있는 것으로 판단되었다. 출구가스의 기체 유동속도가 매우 빠르므로 (100-l10m.sec) 이를 완화하기 위한 디퓨저의 설계가 요구된다고 판단된다. 또 연소기 후방에 물을 주입하는 경우 열교환기 및 기타 부분품에 발생할 수 있는 부식 및 열교환 효율 저하도 간과할 수 없는 문제로 파악되었다. 이러한 기술적 문제가 적절히 해결되는 경우 비활성 가스 제너레이터는 민수용으로는 대형 빌딩, 산림, 유조선 등의 화재에 매우 적절히 사용되어 질 수 있을 뿐 아니라 군사적으로도 군사작전 중 및 공군 기지의 화재 그리고 지하벙커에 설치되어 있는 고급 첨단 군사 장비 등의 화재 뿐 아니라 대간첩작전 등에 효과적으로 활용될 수 있을 것으로 판단된다.

• Journal of the Korea Society of Computer and Information
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• v.28 no.2
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• pp.121-129
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• 2023

In this paper, we developed a traffic signal control system for emergency situations that can minimize loss of property and life by actively controlling traffic signals in a certain section in response to emergency situations. When the emergency vehicle terminal transmits an emergency signal including identification information and GPS information, the surrounding image is obtained from the camera, and the object is analyzed based on deep learning to output object information having information such as the location, type, and size of the object. After generating information tracking this object and detecting the signal system, the signal system is switched to emergency mode to identify and track the emergency vehicle based on the received GPS information, and to transmit emergency control signals based on the emergency vehicle's traveling route. It is a system that can be transmitted to a signal controller. This system prevents the emergency vehicle from being blocked by an emergency control signal that is applied first according to an emergency signal, thereby minimizing loss of life and property due to traffic obstacles.

• Journal of Broadcast Engineering
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• v.24 no.1
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• pp.118-131
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• 2019

In order to provide 8K UHD contents of terrestrial broadcasting with a large capacity, the terrestrial broadcasting system has various problems such as limited bandwidth and so on. To solve these problems, UHD contents transmission technology has been actively studied, and an 8K UHD broadcasting system using terrestrial broadcasting network and communication network has been proposed. The proposed technique is to solve the limited bandwidth problem of terrestrial broadcasting network by segmenting 8K UHD contents and transmitting them to heterogeneous networks through hierarchical separation. Through the terrestrial broadcasting network, the base layer corresponding to FHD and the additional enhancement layer data for 4K UHD are transmitted, and the additional enhancement layer data corresponding to 8K UHD is transmitted through the communication network. When 8K UHD contents are provided in such a way, user can receive up to 4K UHD broadcasting by terrestrial channels, and also can receive up to 8K UHD additional communication networks. However, in order to transmit the 4K UHD contents within the allocated bit rate of the domestic terrestrial UHD broadcasting, the compression rate is increased, so a certain level of image deterioration occurs inevitably. Due to the nature of UHD contents, video quality should be considered as a top priority over other factors, so that video quality should be guaranteed even within a limited bit rate. This requires packet scheduling of content generators in the broadcasting system. Since the multiplexer sends out the packets received from the content generator in order, it is very important to make the transmission time and the transmission rate of the process from the content generator to the multiplexer constant and accurate. Therefore, we propose a variable transmission scheduler between the content generator and the multiplexer to guarantee the image quality of a certain level of UHD contents in this paper.

• Journal of Navigation and Port Research
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• v.36 no.6
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• pp.475-480
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• 2012

In order to establish eLoran (enhanced Long Range Navigation) system, it needs the advancement of receiver, transmitter, data channel addition for Loran information, differential Loran sites for compensating Loran-c signal and ASFs (Additional Secondary Factors) database, etc. In addition, the precise synchronization of transmitting station to the UTC (Coordinated Universal Time) is essential if Loran delivers the high absolute accuracy of navigation demanded for maritime harbor entrance. For better timing synchronization to the UTC among transmitting stations, it is necessary to measure and monitor the transmission delay of the station, and the correction information of the transmitting station should be provided to the user's receivers. In this paper we presented the measurement method of absolute delay of Pohang Loran transmitting station and developed a time delay measurement system and a phase monitoring system for Loran station. We achieved -2.23 us as a result of the absolute phase delay of Pohang station and the drift of Loran pulse of the station was measured about 0.3 us for a month period. Therefore it is necessary to measure the delay offset of transmitting station and to compensate the drift of the Loran signal for the high accuracy application of PNT (Positioning, Navigation and Timing).

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.8
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• pp.1620-1625
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• 2004

To advance fisheries, we set developmental directions of fishery information by grasping present situations and analyzing maritime & fisheries issues. We promote various policies through effective systematical information data bases, based on both control and utilization of oceanic resources. For these puposes, it is imperative that we set up fisheries communication networks. There are satellite assisted informational networks to assist fishing vessels with their marine based movements. However, there's no hope for poorly equipped fishermen to adopt this network because of extravagant network call charges. So we think that using existing SSB communication system is the best plan. We organize fishery communication network by HF SSB communication which doesn't have operational costs. We build wireless transmitting and receiving stations that are basic systems of informnation, and equip wireless data communication systems by the use of wireless communication network protocols in coastal stations. It is necessary that a fish boat has a terminal device for wireless data communication. In this research we can conclude that if we transmit the location of a fishing boat in-real time through GPS channels then we propose that some methods be formulated to able terminal devices on fishing boats to collect various types of information, such as meteorological and oceanic conditions.

• Journal of Broadcast Engineering
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• v.16 no.3
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• pp.394-402
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• 2011

We introduce the standard content identifier Universal Content Identifier (UCI) and a watermarking system that embeds UCI for the broadcast content distribution services. Our proposed UCI embedder is designed in consideration of integrating with the previously established broadcast system and protecting the illegal distribution of broadcast contents. Our goal is that when broadcast content is transmitted, 28 byte UCI is embedded imperceptibly in the content itself in real-time and the embedded UCI is successfully extracted not only in the typical format used in the broadcast content distribution service but also in the illegally distributed broadcast contents. Usually the illegally distributed contents are modified from the original by changing resolutions, frame rates, or adjusting colors. In this paper, we present a watermarking scheme that embeds 28 byte UCI in broadcast content in real-time while keeping the visual quality high and the embedded watermark robust enough to survive through the various modification. The experimental results show that the embedded UCI remains in the various modified versions of content and that the visual degradation by embedding is not noticeable.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.3
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• pp.244-250
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• 2018

Multilateration acquires the transponder signal of target from receivers installed on the ground and calculates the position of the target using the difference of the signal acquisition time of each receiver. One of the factors that influence the positioning accuracy of Multilateration using the TDOA calculation method is the error due to the precision measurement of signal input time. When measuring the signal input time at the receiver, the input signal is sampled using the reference clock of the receiver and a reference sample having the same sampling rate is applied to the cross correlation technique. Therefore, the accuracy of the signal input time is proportional to the reference clock. In this paper, the algorithm for precisely measuring the signal input time by performing cross correlation between the input signal of the receiver and DRS(Delayed Reference Sample) is proposed. In order to verify this, we implemented the pulse signal of the transponder that is transmitted from the target using Matlab. Through the simulation, cross correlation between the proposed DRS and the input signal was performed. From this result, the performance of the precise measurement of signal input time was analyzed.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2010.07a
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• pp.208-211
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• 2010

2012년 지상파 방송은 아날로그 송출을 종료하고 디지털 방송으로 전환된다. 이렇게 전환되는 지상파 디지털 방송은 무료로 누구나 시청할 수 있는 보편적 서비스를 지향하기 때문에, 케이블TV, 위성TV, IPTV 등의 다른 매체와는 달리 기술적 보호조치 없이 방송되고 있다. 또한 DTV 방송프로그램은 원본과 똑같은 화질로 개인이 쉽게 저장할 수 있고 인터넷을 통하여 누구나 쉽게 접근이 가능하기 때문에, DTV 방송프로그램의 무단복제와 인터넷을 통한 불법재배포는 큰 문제점으로 대두되고 있다. 이러한 불법 대량배포는 방송프로그램의 저작권을 심각히 침해할 뿐만 아니라, 방송사의 고품질의 방송프로그램을 제작환경을 더욱 열악하게 만들고 있다. 또한 일반 사용자는 인식하지 못하는 사이에 인터넷을 통해 불법 콘텐츠를 사용하게 되는 악순환에 빠지게 된다. 이에 본 논문은 KBS에서 추진하고 있는 여러 콘텐츠 보호 기술들을 하나의 보호 고리로 연결하는 KBS 보호기술 체계를 소개하고자 한다. 이를 위하여 KBS는 아래의 3가지 보호 기술을 개발하여 체계적으로 연결하여 적용하고 있다. 첫째, 프로그램의 저작권과 배포 정보를 나타내는 프로그램 보호신호(PPI, Program Protection Information)와 워터마크를 방송 신호에 삽입하여 수신기에서의 프로그램 보호를 추진한다, 둘째, 인터넷 OSP(Online Service Provider)와의 제휴를 통하여 콘텐츠 필터링 기술을 도입하여 프로그램 불법 업로드, 다운로드를 방지한다. 셋째, KBS 저작물 인터넷 모니터링 시스템을 개발하여 인터넷 상의 불법 프로그램 배포정보를 획득하여 불법배포가 진행되는 사이트에 보호를 요청한다.

• Journal of Advanced Navigation Technology
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• v.16 no.3
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• pp.526-535
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• 2012

Digital signage in airport is used to provide the flight and airport information to the airport passenger. However, the current digital signage displays one type of contents to all of the airport customers without considering the type of the customer. Thus, the digital signage suffer from the inefficiency problem resulting in lower customer satisfaction. This problem can be solved if we adopt a smart digital signage which can recognize the type of the customer and provide the tailored contents. In this study, we report a smart digital signage using age recognition. Our smart digital signage can recognize the age of the customer in real-time, and provide the tailored contents to the customer. The smart digital signage can improve the airport customer satisfaction and the airport work efficiency by providing the information that is needed by the airport customers.

• The Journal of the Acoustical Society of Korea
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• v.22 no.4
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• pp.276-285
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• 2003

In this paper, we present real-time implementation of a R2MFC/DTMF (R2 Multi Frequency Combinations/Dual Tone Multiple Frequency) tone receiver/sender using a high performance DSP (Digital Signal Processor) and apply it to a carrier class VoIP (Voice over Internet Protocol) gateway system. The Receiver utilizes the Goertzel filter and the sender adopts the harmonic resonant filter. We describe, in detail, the techniques of multi-channel real-time implementation on a Texas Instruments TMS320C62x DSP such as effective PCM (Pulse Code Modulation) in/out by means of DMA (Direct Memory Access) and McBSP (Multi Channel Buffered Serial Port) and message communication via HPI (Host Port Interface), etc. From experimental results, we confirmed that the optimized code provided 780 channel capacity at 250㎒ C6202, and the our R2MFC/DTMF receiver/sender met ITU-T (International Telecommunication Union-Telecommunication) specifications.