• Journal of Digital Contents Society
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• v.8 no.4
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• pp.425-430
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• 2007

Depends on the running dry of the radio resources for the next generation of wireless communication system the estimated possibilities of the visible light which used for the devices such as signal light, the electric display board, guide board and so on applied for the next generation wireless network is the topic to be explored in this paper. Since radiation efficiency utilization for the wireless network has its capacity to become a trend direction we will study also on its application as well as the technique standardization.

• Proceedings of the KAIS Fall Conference
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• 2006.11a
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• pp.167-171
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• 2006

본 연구에서는 통신선 가설 보조 기구인 조가선에 이상 장력이 작용하였을 때 전주의 영향을 유한 요소 해석을 통하여 평가하였고, 전주와 가공 광통신선에 대한 보호 기구를 설계 해석하여 보호시스템을 개발하였다. 보호시스템은 일반하중 또는 풍압과 일반적인 불평형 하중에서는 조가선이 탈락되지 않고 일정강도 이상이 가해지면 조가선이 자동 탈락되어 전주의 절손 방지 및 전주에 거치되어 있는 광통신선의 단선 방지 역할을 한다. 이러한 보호시스템의 구조는 유한 요소 해석을 통하여 해석되어졌고, 실제 제품에 대한 인장강도를 측정함으로써 성능을 입증하였다.

• Journal of Korea Society of Digital Industry and Information Management
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• v.16 no.4
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• pp.29-42
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• 2020

SCADA (Supervisory Control and Data Acquisition) systems for remote monitoring, data acquisition and control are applied to major industrial infrastructures including power, water and railroad. Recently, there are many researches on key management scheme for secure communication due to change to the open network environment. These systems are located at far distances and are connected to the main control center through various types of communication methods. Due to the nature of these systems, they are becoming the significant targets of cyber attack. We propose an efficient key management scheme which is established on ID-based cryptosystem without an expensive computation on MTU (Master Terminal Unit), Sub-MTU, and RTU (Remote Terminal Unit). The proposed method is secure and effective in key management among multiple legitimate devices.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.1
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• pp.45-52
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• 2009

Currently broadcasting and telecommunication has integrated, And IPTV Service has appeared who called TPS(Triple Play Service) which integrated with broadcasting, telecommunication and Phone Service. IPTV provide broadcasting service and VOD(Video on Demand) service, and it must be satisfied digital content security. For this condition, IPTV Forum working on standardization of interface for digital content security. The Security solution for broadcasting and VOD are CAS (Conditional Access System) and DRM(Digital Rights Management). But these solutions manufactured by many vendors, so there is no inter-operability. And after finished standardization of interface for CAS and DRM system, the problem of inter-operability with them will be issued. For this reason, Rights management system which possible to operate independently with platform is necessary. In this paper, To protect multimedia digital content, we designed and implemented Conditional Access Management System.

• KIPS Transactions on Software and Data Engineering
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• v.3 no.6
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• pp.237-242
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• 2014

Current digital door lock systems are mainly designed for users' convenience, so they have weakness in security. Thus, this paper suggests a video digital doorlock system grouped with a relay device, a server, and a digital doorlock with a camera, sensors, and communication modules, which is detecting or recognizing objects approaching to the front of the door lock system and sending images and door-opening information to users' smart devices. Experiments showed that the suggested system has 96~98% recognition rate of approaching objects and requires 17.1~23.9 seconds for transmission on average, depending on network systems. Therefore, the system is thought to have enough capability for real time security response by monitoring the front area of the doorlock system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.3
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• pp.217-223
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• 2013

A digital retrodirective antenna system is easy to modify and upgrade because it can control the phase information of the output signal toward opposite direction to input signal without a priori knowledge of the arrival direction. Due to this advantage, it is possible to perform fast beam tracking. In this paper, a design digital retrosirective array antenna system according to the number of antenna array by using only one digital PLL which finds angle of delayed phase and we test BER performance of this system. When we transmit data at actual communication system, the data modulated onto carrier frequency in order to shift spectrum from base band to another band. So we simulate system considering carrier frequency according to the number of antenna array. As a result, carrier frequency has no impact on the performance.

• Journal of Digital Convergence
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• v.10 no.3
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• pp.265-271
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• 2012

This paper proposes a communication distance performance evaluation method for mobility of service robots equipped with a Wi-Fi module. Service robots have function of mobile communication system according to classified services and utilize a (preferred) communication method, wireless lan(IEEE802.11 a/b/gin) communication method of ISM band(2.4GHz and 5.8GHz). For evaluating degradation performance of wireless data for the service robot's mobility. We measured and presented reference vectors obtained by utilizing a distance attenuation correlation method in the real world environment. To evaluate performance of the proposed method, path loss of reference vectors was assigned to the Azimuth 301W and then transmission rate and the transmit throughput of the test sample were measured by the Chariot. The proposed measurement method is necessary for securing wireless LAN communication distance for mobility of mobile smart device and service robots. In addition, if the proposed measurement method os adopted, It would be expected that mobile smart device vendors would utilize the method as an effective wireless LAN mobility communication distance performance evaluation method.

• Journal of Navigation and Port Research
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• v.47 no.6
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• pp.419-429
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• 2023

The pinnacle of rapidly changing and advancing maritime transportation technology is expected to be the Maritime Autonomous Surface Ship (MASS). The implementation of various services within the MASS is likely to be feasible through the ship-centric network known as the S2X communication system. However, existing communication systems face issues such as service traffic saturation and failure to meet demanded functionalities, necessitating the proactive introduction of additional communication technologies. In this study, the concept of S2X communication for the MASS was redefined, deriving required functionalities and ultimately selecting frequencies suitable for utilization. Candidate frequency groups suitable for the derived communication requirements were identified, and communication frequencies prioritized for the initial application were chosen through expert consensus. It is anticipated that through further research, including experimentation to validate these frequencies, they could be utilized in implementing services for autonomous ship navigation in the future.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2003.11a
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• pp.197-200
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• 2003

MPEG-21은 디지털 객체를 정의하고 이를 네트워크상에서 생성, 변형, 전달, 소비를 위한 통합적 멀티미디어 프레임워크에 대한 국제 표준이다. 디지털 아이템(DI: Digital item)은 MPEG-21 프레임워크 내에서 표준화 된 식별체계, 서술 형식을 따르는 구조화된 디지털 객체이며, 유통, 처리의 최소 단위이다 본 논문에서는 이러한 디지털 아이템을 최종 소비하는 MPEG-21 터미널 구조를 제안하고 이에 대한 설계 및 구현, 그리고 실험 결과를 제시한다

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2003.11a
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• pp.257-260
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• 2003

MPEG-21은 사용자가 다양한 멀티미디어 데이터를 네트워크상에서 생성, 변형, 전달, 소비하기 위한 통합적 멀티미디어 프레임워크를 정의한 국제 표준이 다. MPEG-21 DIA(digital item adaptation)는 멀티 미디어 데이터를 사용자의 환경, 단말기 특성, 네트워크 특성에 대한 정보를 기술할 수 있는 표준을 정의하고 있다. 본 논문에서는 DIA에서 정의한 여러 가지 적응 변환 중 사용자의 관심 영역을 중심으로 한 의미론적 변환 엔진을 구현하였으며, 이에 대한 실험결과를 제시한다 기존의 변환 방법이 비디오 프레임의 전체 크기, 해상도 화질을 조정하였다면, 의미론적 변환은 사용자의 관심 영역을 중심으로 변환을 수행함으로써, 사용자의 관심도를 반영할 수 있는 장점이 있다.