• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2021년도 추계학술대회
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• pp.119-120
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• 2021

국내 어선의 해상업무용 무선설비 및 항해 장비는 IEC 60945를 준용한 KN60945_60533의 성능기준을 따르도록 규정하고 있다. LTE-M 송수신기는 해상업무용 무선설비에 포함되지 않아 기존 선박용 장비들과 동일한 기준을 적용받지 않기 때문에, 방사 방출 또는 전도 방출에 의한 간섭으로 기존 해상업무용 무선설비에 가청 소음을 발생하는 원인이 되고 있다. 본 논문에서는 초고속해상무선통신망 무선설비를 소형선으로 확대보급하기 위해 선결 사항으로 위와 같은 간섭 영향의 원인을 분석하고 관련 대책을 검증 제안한다.

• 한국전자파학회논문지
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• 제19권10호
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• pp.1065-1074
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• 2008

Eureka-147 표준안을 기반으로 하는 지상파 DMB 방송은 현재 다양한 멀티미디어 서비스를 제공하고 있다. 하지만 지상파 DMB 방송에 대한 다양하고 질 좋은 서비스의 제공이 요구되었고, 이에 본 논문에서는 기존의 시스템과의 역호환성을 유지하면서도, UEP와 계층 변조 기법이 적용된 차세대 지상파 DMB 시스템을 본 논문에서 제안하였다. 차세대 지상파 DMB 방송 시스템에서 비균일 16 QAM의 멀티 레벨 변조 방식이 적용되면서 복잡도와 성능의 관점이 고려된 비트 분리 방법을 제안하였고, 기존의 DMB 시스템에서 추가적으로 구성한 부가 서비스 스트림에 DVB-RCS 규격에서 사용하고 있는 double binary turbo 부호를 적용하여 그 성능을 시뮬레이션 하였다. 시뮬레이션 결과, 기존의 지상파 DMB 방송 시스템에 비해 double binary turbo code를 사용한 차세대 지상파 DMB 시스템은 2 dB 이상의 성능의 향상을 확인할 수 있다.

• Journal of information and communication convergence engineering
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• 제6권3호
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• pp.353-357
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• 2008

One objective in developing the next generation of wireless communication systems is to increase data rates and reliability. A promising way to achieve this is to combine multiple-input and multiple-output signal processing with a space-time coding scheme, which offers higher coding and diversity gains and improves the spectrum efficiency and reliability of a wireless communication system. It is noted, however, that time delay differences and phase differences among different channels increase symbol interference and degrade system performance. In this letter, we investigate phase differences and their effects on multiple-input and multiple-output systems, and propose a compensation algorithm for the Rayleigh fading model to minimize their effects.

• 한국항해학회지
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• 제16권2호
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• pp.53-78
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• 1992

GMDSS-the Global Maritime Distress and Safety system which is utilizing the new technologies such as satellite communication system, DSC and NBCP-is effectuated not only by the amendment of SOLAS but also by the conference of RR and IMO's MSC, and will be the major factor of the variation of the demand and supply of Radio Operators. To cope with the GMDSS voluntarily, regulations relating to the radio installation, the posting of Radio Operators, the bounds of duty, etc. must be established and the demand and supply of Radio Operators which take charge of the system must be accomplished pertinently. In this study, the authors suggested some practical schemes to improve the effect of policy as follow. 1. The Ministry of Communication must supervise strictly the arrangement of Radio Operators, especially relating tot he legally qualified complement of Radio Station, and must review the official certification system to upgrade the quality of Radio Operators. 2. The Ministry of Communication must take overall charge of the qualitifications and technical standards of Radio Operators, the extent of their engagement, etc. which are provided by International Regulations. 3. Relating Administrations must cooperate with Shipping Companies in onboard-training to foster and ensure the manpower of Radio Operators. 4. Institutional devices to drive the resolute investment in education and training for mariners, especially for the ship's officers, must be prepared. 5. The Communication Administration and the Korea Maritime and Port Adminstration(KMPA) must cooperate mutually in the balance of the demand and supply of Radio Operators and use make their best to realize more harmonious policies on the demand and supply of manpower.

• 한국전자파학회논문지
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• 제20권3호
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• pp.222-229
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• 2009

본 논문에서는 RFID Tag가 금속판에 접근할 때 통신 거리가 감소되는 RFID 시스템의 통신 거리 증대를 위한 전파흡수체를 개발하였다. 먼저 자성 손실 재료인 Amorphous 금속 분말과 지지재인 CPE(Chlorinated Polyethylene)를 이용하여 조성비별 전파흡수체 샘플을 제작하고, 이 전파흡수체 샘플로부터 구한 재료정수를 이용하여 전파흡수능이 서로 다른 전파흡수체를 각각 설계 제작하였다. 이와 더불어 개발된 전파흡수체를 적용하여 금속에 의해 특성이 열화되는 RFID 태그 안테나의 특성 개선 효과 및 실제 RFID 시스템의 통신 거리 변화를 실험적으로 검토하였다. 그 결과 조성비가 Amorphous metal powder:CPE=80:20 wt.%이고, 두께가 4 mm인 전파흡수체가 금속판으로 인해 통신 거리가 0.8 m인 실제 RFID 시스템의 통신 거리를 5.2 m까지 증대시킴을 확인하였다.

• 한국항해학회지
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• 제17권2호
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• pp.75-106
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• 1993

GMDSS(Global Maritime Distress and Safety system) is a new communication system for the distress and safety at sea which is utilizing the recent advancements in satellite communication and positioning system, digital communication system, computer and microelectronic technology, etc., and will completely substitute the current communication system by 1999. Although the improvements of education for producing qualified Radio Operators as well as the establi-shments of policy for accepting the system are required, the educational institutions and relating administ-rations have not yet prepared the rational and concrete schemes on the educational methods and accepting procedures for the system. In this study, as the result of analyzing the GMDSS, courses of training and relating data, the authors suggested principles for improving the course and contents of education and rational schemes for balan-cing the demand and supply of Radio Operators. The authors expect not only the consequences of this study can be utilized as reference materials for the instruction to ratio communication in the organs of education but also that the following effects can be obtained by the study. 1. Security of distress and safety communication system at sea by the establishment of relating regula-tions. 2. Rationalization of the management of radio communication at sea and improvement of the communi-cation system on the vessel. 3. Upgrading the quality of Radio Operators and presenting schemes for current qualified persons. 4. Activation of industry producing radio instruments. 5. Balance of the demand and supply of Radio Operators and development of shipping industry.

• Journal of information and communication convergence engineering
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• 제9권5호
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• pp.523-529
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• 2011

In this paper an inter-layer protocol, referred to as a Multi-Network Selector (MNS) is proposed for multiband maritime networks. A MNS is located between the data-link layer and the network layer and performs vertical handover when a ship moves another radio network. In order to provide seamless data transfer to different radio networks, the MNS uses received signal strength (RSS) and ship's location information as decision parameters for vertical handover, which can avoid ping-pong effect and reduces handover latency. In addition, we present related issues in order to implement the MNS for a multiband maritime network.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제6권3호
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• pp.247-254
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• 2006

Biometrics are getting more and more attention in recent years for security and other concerns. So far, only fingerprint recognition has seen limited success for on-line security check, since other biometrics verification and identification systems require more complicated and expensive acquisition interfaces and recognition processes. Hand-Geometry can be used for biometric verification and identification because of its acquisition convenience and good performance for verification and identification performance. It could also be a good candidate for online checks. Therefore, this paper proposes a Hand-Geometry recognition system based on geometrical features of hand. From anatomical point of view, human hand can be characterized by its length, width, thickness, geometrical composition, shapes of the palm, and shape and geometry of the fingers. This paper proposes thirty relevant features for a Hand-Geometry recognition system. This system presents verification results based on hand measurements of 20 individuals. The verification process has been tested on a size of $320{\times}240$ image, and result of the verification process have hit rate of 95% and FAR of 0.020.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2019년도 추계학술대회
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• pp.209-210
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• 2019

본 논문은 해상 원격의료진료 시스템 구현을 위한 통신모듈에 관한 내용이다. 해상에서 실시간 원거리 영상통신 및 원격제어를 통한 의료서비스을 구현하기 위한 통신 시스템을 디지털 회로로 구현하였으며 이에 대한 회로구조 및 통신 방법등에 대해 발표하고자 한다.

• Journal of electromagnetic engineering and science
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• 제8권2호
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• pp.70-75
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• 2008

In this paper, the EM wave absorber was designed and fabricated for countermeasure against EMI from a ceiling of a tollgate in ETC system. We fabricated several samples in different composition ratios of MnZn-ferrite, Carbon, and CPE(Chlorinated Polyethylene). Absorption abilities were simulated in accordance with different thicknesses of the prepared absorbers and changed complex relative permittivity and permeability according to composition ratio. The optimized mixing ratio of MnZn-ferrite, Carbon, and CPE was found as 40:15:45 wt.% by experiments and simulation. Then the EM wave absorber was fabricated and tested using the simulated data. As a result, the developed EM wave absorber has the thickness of 3.3 mm and absorption ability was more than 20 dB in the case of normal incidence and more than 11 dB for the incident angle from 15 to 45 degrees at 5.8 GHz. Therefore, it was confirmed that the newly developed absorber can be used for ETC system.