• Journal of Digital Convergence
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• v.12 no.8
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• pp.249-255
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• 2014

In this paper, we proposed to reduce the interference in the visible light Communication with multi-LEDs for improving the performance of BER and satisfied the QoS. LED is not only lighting device, but also transmitting device in the VLC. Our proposed system is aim to decrease the interference in the multi-LEDs. In addition, it occurred the ISI and CCI by transmitter to receiver different distance. To solve this problem, we proposed the multi-LEDs system using walsh code to reduce ISI and CCI. In addition, our proposed system is able to improve the performance of BER and satisfied the Qos to desire users.

• Convergence Security Journal
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• v.12 no.1
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• pp.35-42
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• 2012

Increase of data traffic and the advent of new real-time services require to change from the traditional TDM-based (Time Division Multiplexing) networks to the optical networks that soft and dynamic configuration. Voice and lease line services are main service area of the traditional TDM-based networks. This optical network became main infrastructure that offer many channel that can convey data, video, and voice. To provide high resilience against failures, Packet-optical networks must have an ability to maintain an acceptable level of service during network failures. Fast and resource optimized lightpath restoration strategies are urgent requirements for the near future Packet-optical networks with a Generalized Multi-Protocol Label Switching(GMPLS) control plane. The goal of this paper is to provide packet-optical network with a hierarchical multi-layer recovery in order to fast and coordinated restoration in packet-optical network/GMPLS, focusing on new implementation information. The proposed schemes do not need an extension of optical network signaling (routing) protocols for support.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.6
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• pp.26-36
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• 2009

ad-hoc network is self-constructed by mobile hosts without any infrastructure. And the hosts collaborate with each other for routing packet by means of multi-hop communication. But it is too hard to deploy ad hoc network at the large area because of the salability problem caused by low network throughput. network throughput decrease is due to contention on the air among the neighbor host and single interface limitation, and broadcast flooding through overall network. In this paper, to solve the ad hoc scalability problem, we propose mesh network based scalable hierarchical ad hoc architecture, and also propose the adaptation methods for inter-working with the host not including ad hoc functions and the legacy infra-network.

• 한국벤처창업학회:학술대회논문집
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• 2017.04a
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• pp.40-40
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• 2017

국내 대학은 연구 및 교육 기관으로서의 중요성과 함께 창업에 기여해야 할 사회적 책무를 지고 있다. 대학이 축적한 각종 지식 성과와 함께 연구와 개발 인프라를 활용하고 대학생 및 대학원생의 창의적 아이디어의 활용 가치를 높여 경제 활성화를 위한 새로운 성장 엔진을 개발해야 한다. 또한 창업연구와 창업지원 사업에 대한 사회적 요구에 맞추어 대학은 창업기능을 구조 혁신의 도구로 삼을 기회를 가지게 되었다는 점도 주목해야 한다. 본 연구는 한국 대학의 창업지원 기관의 역할 정립을 위한 학술적 지식을 되짚어 보고 창업을 중심으로 한 대학의 적극적인 창업지원단 구축 모델에 대한 논의를 담고 있다. 창업교육과 창업지원에 관한 기존의 연구와 2차 통계자료를 기반으로 창업지원 방향에 관한 시사점을 획득하고 대학 혁신을 위한 창업지원 모델인 WoW! Valley Model을 제안한다. 본 모형은 창업지원단의 역할 정립에 도움을 주고 대학 창업지원의 정책 수립의 기초를 제공할 것으로 본다. 국내외 경제 여건의 악화와 글로벌 경제 침체 속에서 창업의 사회적 중요성은 점차 커지고 있다. 이러한 상황에서 대학의 창업 활성화는 시대적 과제라 할 수 있다. 체계적인 창업 지원 정책을 대학이 주도하고 현실 학문적 성격을 강화하는 방향으로 체질을 개선하는 일이 시급하다. 본 연구는 대학의 창업지원단 활동의 새로운 모델을 제시하고 있다. 이미 국내의 많은 대학들이 창업지원을 위한 센터나 지원단을 운영하고 있으며 독자적인 체계를 갖추고 있다. 그러나 창업지원을 중심으로 대학의 기능을 재편하는 등의 혁신 체계로서의 창업지원단 운영 모델은 수립 및 시행된 경우가 드물다. 본 연구는 창업교육과 창업지원에 관한 기존의 연구 성과를 되짚어 보고 국내 대학의 창업지원을 위한 새로운 시각을 제시한다. 창업 지원단의 수립 및 운영 모형에 관한 논의가 절실한 시점에서 본 연구는 연구자와 대학 운영자 및 정책 입안자에게 의미 있는 시사점을 줄 것으로 기대한다. 한편, 본 연구는 개념적 디자인을 제시하는 수준이므로 디자인을 평가하여 새로운 지식을 얻는 등의 후속 과정을 거쳐 보완될 필요가 있다. 다중 사례 연구와 실행 연구(Action Research) 등의 실증 방법을 통해 본 연구의 후속 결과가 요구된다.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.6 s.348
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• pp.39-45
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• 2006

n a hybrid ad-hoc network, wired network and a mobile ad-hoc network are connected by the internet gateway. To provide seamless service for internet users in the hybrid ad-hoc network, an efficient internet gateway selection technique and a fast handover technique are needed. In this paper, we propose a seamless handoff technique for providing mobility of mobile hosts in hybrid ad-hoc networks. The proposed internet gateway re-registration algorithm improves general handoff performance. Moreover, the handoff processing time within certain range of area is reduced by using mobility management agent(MMA). In addition the packet loss is reduced when handoff occurs out of the range of MMA by tunneling technique.

• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.5
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• pp.1041-1051
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• 2012

Attack on Cloud Computing, an intensive service solution using network infrastructure recently released, generates service breakdown or intrusive incidents incapacitating developmental platforms, web-based software, or resource services. Therefore, it is needed to conduct research on security for the operational information of three kinds of services (3S': laaS, PaaS, SaaS) supported by the Cloud Computing system and also generated data from the illegal attack on service blocking. This paper aims to build a system providing optimal services as a 4-stage defensive method through the test on the attack and defense of Cloud Computing services. It is a defense policy that conducts 4-stage, orderly and phased access control as follows: controlling the initial access to the network, controlling virtualization services, classifying services for support, and selecting multiple routes. By dispersing the attacks and also monitoring and analyzing to control the access by stage, this study performs defense policy realization and analysis and tests defenses by the types of attack. The research findings will be provided as practical foundational data to realize Cloud Computing service-based defense policy.

• Journal of Advanced Navigation Technology
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• v.19 no.6
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• pp.534-543
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• 2015

This paper introduces the time-misalignment error between multiple range measurements acquired by an onboard distance measuring equipment (DME) interrogator and proposes an efficient position determination method that can mitigate the negative effects of the time-misalignment error. The introduced time-misalignment error does not occur in conventional utilization of DME combined with VHF omnidirectional range (VOR). The proposed position determination method projects all the DME range measurements acquired irregularly during an interval to the same time instance where the aircraft position is determined. By the simulation utilizing a representative aircraft trajectory, it is shown that it is possible to estimate the horizontal position accurately without any changes of ground DME facilities.

• Journal of Korea Society of Industrial Information Systems
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• v.22 no.1
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• pp.1-9
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• 2017

With the Development of Wireless Network Technology and Wireless Link Technology, Wireless Mesh Network (WMN) is Attracting Attention as a Key Technology to Construct the Wireless Transit Network. The WMN has been Studied for a Long Time in Various Fields, however there are still many Problems that have not been solved yet. One of them is the Routing Problem to find an Optimal path in a Multi-hop Network Composed of Wireless Links. In the Hybrid-WMN, which is one of the Three Types of WMN, Optimal Path Selection Requires Research on Path Search Protocols that Effectively use the Infrastructure Mesh as a Transit Network, Together with Research for a Routing Metric with Excellent Performance. Therefore, this Paper Proposes a Dual Mode-AODV(Ad hoc On-demand Distance Vector) for Hybrid-WMN. Simulation result shows that the Path Selection Delay was Reduced by 52% than AODV when the Proposed Dual Mode-AODV was applied.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.8
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• pp.718-727
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• 2016

Korean ground systems have started to be developed for mission control and payload data processing since 1990s. International technology cooperations were needed in the early development phase of ground system for science experiment satellite, LEO satellite and GEO satellite and then they have been developed as domestic own technology since acquiring early technology. Our country has developed total 14 ground systems until now, this paper suggests prospect and direction on ground system development in the base of such development experiences. Mission control system is needed to develop multi-satellite mission control system in the base of technology of re-configure, re-use and automation. Processing system is needed to acquire processing technology for kinds of payload sensor data and study inter-operation to integrate and use outputs which are processed between users. Finally, national ground system infrastructure is needed to operate kinds of lots of satellites at worldwide area.

• Spatial Information Research
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• v.21 no.1
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• pp.87-100
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• 2013

Recently, the use of locational information is growing rapidly. GPS technology has been adopted generally for obtaining locational information in outdoor spaces. In the other hand, the researches on indoor positioning have been carried out applying WLAN, RFID or Bluetooth technology because of the multi-path interference of GPS signal caused by the physical obstacles such as walls or columns in buildings. However, such technologies for indoor positioning cost too much to build sensing infrastructure and compute-intensive processes are involved. Furthermore, the accuracy of location estimation is variable caused by interior structures in buildings. In this study, to make up for the limitations, descriptive data such as phone number, unique room numbers, or business names readily available in mixed-use buildings is used for extracting location information. Furthermore, during the process, a geocoding method using character matching is applied to this study enabling prompt location estimation and sublating the fluctuation of accuracy caused by interior structures. Based on the proposed method in this study, an architecture is designed, and three-dimensional viewer program is developed for the implementation of this study. Also, this research is quantitatively analyzed through match rate and processing time of proposed method.