• Proceedings of the Korea Information Processing Society Conference
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• 2007.05a
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• pp.1306-1309
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• 2007

본 논문에서는 indoor 환경에서 CR 네트워크를 이용하기 위한 방안으로 CR-Wi-Fi device 시스템을 제안했으며 IU 을 보호하는 방법으로 CR beaconing 을 제안했다. IU 가 출현하면 UHF, VHF band 와 ISM band 로 동시에 이를 알리고 CR 네트워크가 간섭을 주는 경우 사용 중이던 채널 사용을 중지 혹은 이동하도록 명령해야 한다. 본 논문에서는 CR beaconing 방식을 제안하여 보다 효과적인 IU 보호 및 복구를 수행하도록 하였다.

• Journal of Advanced Navigation Technology
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• v.11 no.1
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• pp.17-23
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• 2007

This paper, describes the VDR physical layer design in VDL Mode-2 in order to meet the requirements of International standards. VDR's frequency band is 117.975~137MHz, and CSMA(Carrier Sense Multiple Access), D8PSK(Differential Eight Phase Shift Keyed), 25KHz's channel bandwidth use. The analysis of the isolated channel from near channels, sensitivity of the receiver, dynamic range of the receiver, linear of the transmitter and energy of spurious for linear and non-linear simulation as a requirement condition of performance of VDR and teaches the course of design. The transmitting power level should be lower than 5dB from Po1dB point and the selected IF frequency is 45MHz to suppress the spurious signals. The receiver designed has 4.5dB of Noise figure, 27.52dB of Es/No, Mixer isolation up to 30dB, IIP3 power of LNA up to +10dBm to minimize the intermodulation.

• Journal of the Korean Institute of Telematics and Electronics
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• v.13 no.2
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• pp.14-22
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• 1976

This research was started to develop a VHF television antenna which secures good pictures in spite of the disturbance from tile rear side. In a year of research, an antenna which front to banck ratio is gyrator than 30dB and whose side lobe level is smaller than -30dB alas been developed. This new antenna was designed log-periodically for the sake of wide frequency bandwidth which is necessary to cover all tile high channel. And it was found having characteristics of anti-interference against the disturbance wave from tole behind, and anti-ghosts from the reflected waves. Furthermore, the gain of this new antenna is reasonablly high, because of its low side lobe level. After all, the developed antenna is silpposcd to increace the service area considervably and to improve the TV receiving certainly.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.6
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• pp.681-688
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• 2016

Several VHF bands for the use in analog communications has been changed to those for the use in new maritime digital communications by WRC-12. ITU-R M. 1842-1 has been also standardized, recommending the characteristics of maritime digital communication systems. In addition, a Shipborne Ad-hoc Network (SANET) has been introduced by IMO in order to provide ships, which cannot be connected to a shore directly, with maritime digital data exchange services with the help of ad-hoc communication. In this paper, several functionalities of the SANET, including channel access, route determination to a shore, and data exchange, are verified via sea trials. It is expected that the SANET can be applicable to collecting and analyzing maritime information, facilitating the entry and departure of vessels, and the communication infrastructure of e-navigation.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.10a
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• pp.765-768
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• 2001

A universal shipborne automatic identification system(AIS) uses self-organised time division multiple access(SOTDMA). The performance evaluation system of the SOTDMA algorithm for AIS is needed to implement it efficiently. This paper shows the method of designing it. Real ships access the VHF maritime mobile band but in this performance system, several ship objects access the shared memory. Real ships are designed as the object and the wireless communication channel is designed as the shared memory. This system shows several stations are assigned the transmission slot by the SOTDMA algorithm

• Journal of Advanced Navigation Technology
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• v.17 no.5
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• pp.516-523
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• 2013

In this paper, The path loss model of Air Traffic Control(ATC) telecommunication radio channel has been studied at the Incheon International Airport(IIA) with the terminal with two antlers. We measured two frequencies among VHF/UHF channel bands. The transmitting site radiated the Continuous Wave(CW). The propagation measurement was taken using the moving vehicle equipped with receiver and antenna. The transmitting power, frequency and antenna height are the same as the current operating condition. The path loss exponent and intercept parameters were extracted by the basic path loss model and hata model. The path loss exponents at passager terminal areas were 3.32 and 3.10 respectively in 128.2 MHz and 269.1 MHz. The deviation of prediction error is 9.69 and 9.65. The new path loss equation at the terminal area was also developed using the derived path loss parameters. The new path loss was compared with other models. This result will be helpful for the ATC site selection and service quality evaluation.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.11
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• pp.2451-2456
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• 2011

This paper is a study on the high power amplifier to fulfill standards of the MOPS. VDR's frequency band is 117.975~137MHz, and CSMA(Carrier Sense Multiple Access), D8PSK(Differential Eight Phase Shift Keyed), 25KHz's channel bandwidth use. It also stated in DO-281A MOPS output power, symbol constellation error, spurious emissions, adjacent channel power must be met. We designed and measured the performance. The 38dB of the IM3 satisfies the MOPS standard.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2012.06a
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• pp.545-547
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• 2012

본 연구는 VHF채널 정숙도를 확보하는 것을 목적으로 하여, 교신시간을 불필요하게 연장케 하는 VTS교신효율 저해요소를 구체적으로 수치화하기 위하여 마련되었다. 하루 24시간 동안의 교신을 기록조사하여 교신내용 형식 및 교신주체별 교신소요시간 등을 분석하였고, 교신시간대 관제사 별 교신수반결과 및 1회 교신 중 많은 정보가 수반될 경우 발생될 수 있는 청자의 인지실패율에 초점을 두고 연구를 진행하여 VTS생산자료의 이용방향을 제시하는데 의의를 두었다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2015.07a
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• pp.351-353
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• 2015

2014년 4월 1일자로 항만VTS의 관제구역이 레이더 탐지가 가능한 12마일까지 확대됨에 따른 관제섹터 운영 방안 중 항만의 지리적, 환경적 특성에 따라 지역으로 구분하는 분업방식의 관제운영방식이 아닌 전체 관제구역을 주-보조 관제사가 동시에 확인하는 협업방식의 관제운영석 운영방안에 대하여 연구하고자 함.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2011.06a
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• pp.126-128
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• 2011

AIS가 도입된 이후 선박확인절차에 필요한 VHF교신량 감소, Ship to Ship, Ship to VTS간 안전통신의 기회증대와 RADAR에서 발생하는 Swap(물표바뀜)현상 감소 등 자동으로 선박정보를 수신함으로써 VTS구역의 전체적인 통항이미지를 관제사가 쉽게 그릴 수 있어 보다 안전한 관제업무를 수행하는데 기여하고 있다. 하지만 AIS탑재선박의 증가로 AIS기지국/선박국 통신환경에 따른 채널간섭과 AIS신호의 ERROR(오류) 정보 등이 관제업무를 더욱 위험한 상황으로 만드는 경우들이 발생하고 있다. 따라서 본 논문에서는 관제업무를 수행함에 있어서 경험하였던 AIS ERROR 정보로 인한 위험했던 상황들을 분석하여 다른 관제사가 업무 수행시 합리적인 판단을 내릴 수 있도록 AIS특성 및 개선방안을 제시하고자 한다.