• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.4
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• pp.585-590
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• 2021

This paper proposes a 3-user non-interfering binary pulse amplitude modulation(2PAM) and non-orthogonal multiple access(NOMA) scheme, to improve the bit-error rate(BER) performance of the weakest channel user with the tolerable BER loss of the stronger channel users. First, we design the 3-user non-interfering 2PAM NOMA, and then derive the closed-form expressions for the BERs of the proposed scheme. Numerical results are also presented to demonstrate that the BER of the weakest channel user improves greatly, with the small BER losses of the stronger channel users. As a result, the non-interfering 2PAM could be considered in NOMA of 5G systems.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.1
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• pp.274-281
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• 2015

Firms are becoming increasingly dependent on external resources for a competitive advantage in environmental turbulence, the requisite speed of organizational change. Therefore, they focused on an 'Open Innovation'. This study examined the relationships among entrepreneurial orientation, learning orientation, open innovation, and new product development. The results provide broad support for the following: (1) entrepreneurial orientation and learning orientation strongly drive open innovation, (2) open innovation has a significant effect on new product development, and (3) learning orientation has a positive effect on open innovation and new product development. These results provide unique insight into how firms develop new product through open innovation. This study also addresses the implications of these results and the possible limitations of the research.

• Journal of Convergence for Information Technology
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• v.10 no.9
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• pp.22-27
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• 2020

In the fifth generation (5G) networks, the mobile services require much faster connections than in the fourth generation (4G) mobile networks. Recently, as one of the promising 5G technologies, non-orthogonal multiple access (NOMA) has been drawing attention. In NOMA, the users share the frequency and time, so that the more users can be served simultaneously. NOMA has several superiorites over orthogonal multiple access (OMA) of long term evolution (LTE), such as higher system capacity and low transmission latency. In this paper, we investigate impact of channel estimation errors on successive interference cancellation (SIC) performance of NOMA. First, the closed-form expression of the bit-error rate (BER) with channel estimation errors is derived, And then the BER with channel estimation errors is compared to that with the perfect channel estimation. In addition, the signal-to-noise (SNR) loss due to channel estimation errors is analyzed.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.23 no.3
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• pp.531-543
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• 2013

The destruction and prejudice of major infrastructure such as energy, broadcast, communication and transportation could result in a threat to individual rights and liberties, as well as social and economic losses. If a traffic signal control facilities have been violated, the lives of the citizens discomfort as well as causing social disruption such as traffic accident. Because the control system is operating as a closed network and you think it is safe, the information protection system has not been built or security patches and anti-virus updates do not work properly. So, cyber attacks by security vulnerabilities are exposed. Therefore, there is a need to identify the characteristics of the system, and develop appropriate countermeasures in order to prevent cyber attacks and prejudices incidents. This paper examines the vulnerabilities of Intelligent Transport Systems and proposes the improvement of security vulnerabilities.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.5
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• pp.19-24
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• 2019

The development of ICT technology has a huge impact on the existing closed CCTV security equipment market. With the importance of video data particularly highlighted in areas such as self-driving cars, unmanned vehicles and smart cities, various technologies using video are emerging. In this paper, we proposed a method to transmit videos and metadata as a part of smart city integration, and to solve the traffic, environment and security problems caused in urban life by utilizing the metadata instead of using CCTV videos for simple recording purposes, and reverse tunneling technique was designed and implemented as a method for accessing CCTV videos for vehicles from remote locations. Integrated management of CCTV videos and metadata for vehicles that have been used only for limited purposes in closed environments will enable efficient operation of integrated centers in real time required by smart cities, such as vehicle status check, road conditions and facility management.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.40 no.6
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• pp.633-641
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• 2020

Residential complexes offer a sense of community and convenience, but making closed and privated space have been criticized.Closed urban spaces have issues encouraging residential segregation.large apartment complexes over 1,000 households,the most poular housing type in Korea, seems to make urban space more closed and privated than ever before. Our study puts forward and tests the hypothesis that large apartment complexes with over 1,000 households are linked to residential segregation. First of all, we examined the degree of residential segregation of metropolitan cities in Korea over a nine-year period (2011-2019). The dissimilarity index and the delta index were used for determining the extent of residential segregation. Next, we tested our hypothesis by Spearman's rank correlation analysis. Spearman's rank correlation analysis was performed on the residential segregation index per administrative division ("dong") and the number of large apartment complexes per administrative division ("dong").

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.85.1-85.1
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• 2010

캐스케이드형 연료전지 시스템에 있어서 각 스택의 단에서 전기화학반응에 의해 생성된 물을 분리하여 적절하게 배출시켜주는 것은 스택의 성능 및 내구성 향상을 위해 매우 중요하다. 이를 위해 연료전지 스택 각 단의 상이한 조건에 맞는 기액분리기의 설계가 필요하다. 유량에 따른 기액분리기의 부피와 원활한 연료 가스와 생성수의 분리를 위한 내부구조 및 입구 속도 등의 변수들에 따라 기액분리기의 성능 뿐만 아니라 연료전지 시스템 전체의 성능에 영향을 준다. 그러나 기액분리기의 폐쇄적 구조 때문에 실험을 통해 내부의 거동 및 현상을 파악할 수 없어 앞서 언급한 변수들의 효과를 확인할 수 없는 문제점이 있다. 이에 CFD(Computational Fluid Dynamics, 전산유체역학)를 활용하여 각 조건에 따른 기액분리기 내부의 현상을 파악하고 이를 통해 기액분리기 설계를 최적화하였다.

• Information and Communications Magazine
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• v.33 no.12
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• pp.12-21
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• 2016

사물인터넷(Internet of Things, IoT) 분야는 모든 기기, 사람, 사물 등이 네트워크로 연결되는 초연결 사회를 지향한다. 이에 반해 전력시스템은 폐쇄망으로 운영되고 있으며, 차세대 전력망이라 일컬어지는 스마트 그리드 환경에서도 개방형 양방향 통신을 기반으로 논의는 되고 있으나, 정보보안 취약성이 높아지고 사고 위험이 증가함에 따라 전력망의 안전성 및 신뢰성 확보에 대한 중요도가 증가하고 있다. 이처럼 초연결 사회를 전력분야에 적용하기 위해서는 적용대상의 정의, 적용방법 등에 대한 기본적인 표준 정립을 통해 IoT 확산 저해요인을 조기에 해소하는 것이 필요하다. 본고에서는 전력 및 에너지 분야에 사물 인터넷을 도입하고 활성화 하기 위해 필요한 에너지 IoT(eIoT) 표준 시스템에 대해 알아본다.

• Proceedings of the Korea Contents Association Conference
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• 2017.05a
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• pp.363-364
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• 2017

1882년 최초의 발전소가 생긴 이래로 전기는 경제성장의 필수적 요소가 되었다. 전기는 빛의 속도로 움직이는 특성으로 인해 정전과 같은 사고에 대처하기 위해 중앙 집중적이며 폐쇄적인 체계를 가졌으나 온실가스 감축 협약, 신재생에너지의 확산 등으로 근본적인 변화를 맞이하고 있으며 최근 인공지능의 급격한 발전으로 전력망 관리에도 인공지능을 도입하는 것에 대한 논의가 필요한 시점이다. 본 논문은 전력망에 인공지능이 결합된 에너지 로봇이라는 개념을 제안하여 점차 가속화 되고 있는 지능화의 흐름 속에서 전력 시스템이 나아가야 할 방향에 대해 고찰하고자 한다.

• Proceedings of the Korea Multimedia Society Conference
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• 2002.05c
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• pp.124-127
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• 2002

EDI를 사용한 전자문서 처리는 두 기업간의 데이터를 전달하기 위해 VAN을 이용하여 데이터를 전달했으나 VAN의 폐쇄성으로 인해 확장에 문제가 제시되었다. 이러한 문제점을 해결하기 위하여 다양한 문서구조 표현이 가능한 XML (eXtensible Markup Language)을 활용한 EDI 서비스 환경으로 옮겨가고 있다. 본 논문에서는 JDBC 브리지를 사용하여 두 관계형 데이터베이스에 존재하는 EDI 메시지를 브러커시스템를 이용한 XML 변환기법을 제안한다. 변환된 XML을 사용하여 스키마를 그대로 복구하는 동시에 정의된 테이블에 원래 레코드들을 그대로 삽입하는 방법을 제시하면서, 반드시 동일한 데이터베이스 관리시스템을 사용해야 한다는 전제조건을 필요했던 기존방식을 탈피했으며 외부로 전달할 경우 환경에 따라 제대로 동작하지 않을 가능성이 높았던 제한점을 극복했다.