• 한국컴퓨터정보학회논문지
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• 제22권9호
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• pp.91-97
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• 2017

IoT (Internet of Things) systems are based on heterogeneous hardware systems of different types of devices interconnected each other, ranging from miniaturized and low-power wireless sensor node to cloud servers. These IoT systems composed of heterogeneous hardware utilize data sets collected from a particular set of sensors or control designated actuators when needed using open APIs created through abstraction of devices' resources associated to service applications. However, previously existing IoT services have been usually developed based on vertical platforms, whose sharing and exchange of data is limited within each industry domain, for example, healthcare. Such problem is called 'data silo', and considered one of crucial issues to be solved for the success of establishing IoT ecosystems. Also, IoT services may need to dynamically organize their services according to the change of status of connected devices due to their mobility and dynamic network connectivity. We propose a way of dynamically composing IoT services under the concept of WoT (Web of Things) where heterogeneous devices across different industries are fully integrated into the Web. Our approach allows developers to create IoT services or mash them up in an efficient way using Web objects registered into multiple standardized horizontal IoT platforms where their resources are discoverable and accessible. A Web-based service composition tool is developed to evaluate the practical feasibility of our approach under real-world service development.

• International Journal of Internet, Broadcasting and Communication
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• 제12권1호
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• pp.7-13
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• 2020

We describes V2X technology, a connectivity-based recognition technology that is attracting attention as a key technology for implementing autonomous driving technology, and autonomous communication modules that implement ADAS technology, a sensor-based recognition technology. It also explains the trends in V2X technology standardization centered on IEEE 802.11p, which is a WAVE technology standard based on Wi-Fi/DSRC. Finally, we will discuss the market growth trend of V2X communication modules in the United States, the leading V2X technology module, and the development of technology development trends of major domestic and international companies that are leading the global technology market related to V2X communication modules. V2X and ADAS technologies will be the biggest influence on automotive purchasing decisions. In recent years, V2I mandates have been promoted beyond V2V, mainly in developed countries such as the United States. The related industry needs to focus on the development of information transmission network technology that can support high frequency high efficiency(transmission rate) and sophisticated positioning accuracy beyond conventional vehicle communication.

• 디지털산업정보학회논문지
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• 제6권1호
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• pp.83-90
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• 2010

DTNs (Delay Tolerant Networks) refer to the networks that can support data transmission in the extreme networking situations such as continuous delay and no connectivity between ends. DTMNs (Delay Tolerant Networks) are a specific range of DTNs, and its chief considerations in the process of message delivery in the routing protocol are the transmission delay, improvement of reliability, and reduction of network loading. This article proposes a new LCN (Largest Common Neighbor) routing algorism to improve Spray and Wait routing protocol that prevents the generation of unnecessary packets in a network by letting mobile nodes limit the number of copies of their messages to all nodes to L. Since higher L is distributed to nodes with directivity to the destination node and the maximum number of common neighbor nodes among the mobile nodes based on the directivity information of each node and the maximum number of common neighbor nodes, more efficient node transmission can be realized. In order to verify this proposed algorism, DTN simulator was designed by using ONE simulator. According to the result of this simulation, the suggested algorism can reduce average delay and unnecessary message generation.

• 한국콘텐츠학회논문지
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• 제20권8호
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• pp.637-644
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• 2020

VANET (Vehicular Ad Hoc Networks)은 차량 간, 차량과 인프라 간의 네트워크이다. 높은 이동성, 이동 제한, 장애물에 의한 신호 방해와 같은 VANET 고유의 특성은 안정적인 VANET 서비스 제공을 어렵게 한다. 이를 해결하기 위해, 본 논문에서는 기존 버스 기반 클러스터링을 개선한, 차량 종류 기반 우선순위 클러스터 방법을 제시한다. 제안 알고리즘은 차량 종류, 예상 통신 수명, 주변 노드 링크 차수를 바탕으로 우선순위, 링크 품질, 연결성을 평가해 클러스터를 구성한다. 차량의 종류를 바탕으로 미리 결정된 우선순위를 활용함으로써 클러스터 헤드 선택을 단순화하고 클러스터 커버리지를 높이고자 한다. 제안 알고리즘은 커넥티드카 환경에서 안정적인 서비스를 제공하는데 기여함으로써 다양한 서비스 활성화의 기반이 될 것으로 기대된다.

• 한국위성정보통신학회논문지
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• 제8권4호
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• pp.70-74
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• 2013

최근 모바일 디바이스 보급의 확산으로 다양한 기종의 디바이스를 다수 보유중인 사용자의 수가 지속적으로 증가하고 있는 추세이다. 이에 따라 하나의 미디어 콘텐츠를 사용자가 보유한 다양한 기기에서 서로 공유해야 할 필요성이 증가하고 있으며, 이는 연결성, 이동성, 통합성 기반의 N-screen 서비스의 확대를 가지고 왔다. N-screen 서비스는 하나의 미디어 콘텐츠를 공유하여 사용자가 보유한 다양한 디바이스에서 서로 이어보기가 가능하게끔 서비스를 제공한다. 그러나 N-screen 서비스들은 서비스 제공 사업자의 전용 플랫폼에서 시행되는 문제점을 가지고 있다. 따라서 본 논문은 개방형 서비스 플랫폼에서의 이어보기 기능의 설계를 위하여 시험적으로 이어보기 기능을 제공하는 RESTful 기반의 이어보기 기능 제공이 가능한 프로토타입 프로그램을 개발하였으며 동작검증은 Android - PC간 시행하였다.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2008년도 추계종합학술대회 B
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• pp.66-69
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• 2008

IP계층에서의 이동성 지원에 대한 연구가 활발히 진행되어 IETF에서 MIPv6에 대한 표준화가 진행되었다. MIPv6는 이동 노드가 망과 망 사이를 이동할 때, 서비스에 대한 연결성을 유지하여 끊김 없는 통신을 가능하게 해주며, 이러한 방법을 핸드오버라고 한다. IEEE 802.21에서는 MIH(Media Independent Handover)라는 끊김 없는 핸드오버를 위한 방법을 표준화했다. MIH는 하위 레이어와 상위 레이어에서의 핸드오버를 위해 세 가지 서비스를 사용하였으며, 본 논문에서는 기존의 MIH에 두 가지 모드를 적용하여 네트워크 시뮬레이터에서 듀얼 모바일 호스트와 싱글 모바일 호스트의 성능 평가를 수행하였다.

• 한국통신학회논문지
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• 제35권11B호
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• pp.1676-1684
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• 2010

전술 네트워크 환경은 분산된 구조 하에 노드의 이동성이 보장되는 망 구조를 지향하며, 상용 통신망에 비해 상대적으로 열악한 무선 채널 환경의 특성이 고려되어야 한다. 이러한 환경에서 신뢰성 있는 데이터 전송을 위해서는 경로 결정 시 다양한 무선 채널 환경 요소 및 기동 노드의 상태를 자체적으로 인지하여, 전송 트래픽의 QoS(Quality of Service) 요구조건에 적합한 최적 경로 선정이 이루어져야 한다. 본 논문에서는 전술 네트워크 환경의 서비스 요구 조건 및 트래픽 특성을 정의하고, 이를 기반으로 라우팅 메트릭(Routing Metric)의 선별적인 선을 통해 최적경로를 산출함으로써 효율적 데이터 전송이 가능한 AODV-IMTC(Integrated Metrics and Traffic Characteristics)를 제안한다.

• ETRI Journal
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• 제36권4호
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• pp.554-563
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• 2014

The burgeoning growth of real-time applications, such as interactive video and VoIP, places a heavy demand for a high data rate and guarantee of QoS from a network. This is being addressed by fourth generation networks such as Long-Term Evolution (LTE). But, the mobility of user equipment that needs to be handed over to a new evolved node base-station (eNB) while maintaining connectivity with high data rates poses a significant challenge that needs to be addressed. Handover (HO) normally takes place at cell borders, which normally suffers high interference. This inter-cell interference (ICI) can affect HO procedures, as well as reduce throughput. In this paper, soft frequency reuse (SFR) and multiple preparations (MP), so-called SFRAMP, are proposed to provide a seamless and fast handover with high throughput by keeping the ICI low. Simulation results using LTE-Sim show that the outage probability and delay are reduced by 24.4% and 11.9%, respectively, over the hard handover method - quite a significant result.

• 한국BIM학회 논문집
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• 제8권4호
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• pp.72-79
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• 2018

Rapid developments around the world have resulted in urban expansion, habitat destruction, habitat fragmentation, and pollution problems, which are the main reasons for the decline in biological diversity. The United Nations warns that many animals and plants will die out in the near future if this continues. This study was performed to propose a map of eco-corridor suitability analysis of Korean water deer(Hydropotes Inermis) to enhance biodiversity in Chuncheon city. Eight factors affecting habitat suitability were elevation, aspect, slope, forest type, distance to the road, distance to the stream, land use and green connectivity. Previous study analysis on the mobility behaviour of the Korean water deer(Hydropotes Inermis) produced a habitat suitability map by determining the threshold and assigning a value between 0 and 1 depending on the habitat suitability using the fuzzy function. A method of analysis was proposed for a number of eco-corridor through comparative analysis of the data from the produced habitat suitability map and the road-kill point. The previous studies were focused on Backdudaegan region and national parks except for urban cities. The potential habitat map of Korean water deer could be helpful as a way to prevent habitat disconnection and increase species diversity in urban areas.

• 한국IT서비스학회지
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• 제22권6호
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• pp.115-132
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• 2023

This study aimed to propose application directions for South Korea's digital health policy by conducting a literature review, data analysis, and examining foreign cases. The objective was to enhance the healthcare rights of individuals with disabilities, considering the potential expansion of the digital health policy. The findings indicate that digital health holds significant promise in improving mobility and accessibility for the healthcare rights of disabled individuals in Korea. However, addressing the digital gap is crucial for achieving smooth utilization. To ensure seamless use of the digital health system, it is imperative to attain digital inclusion, encompassing digital technology, connectivity, and accessibility. Additionally, establishing governance for digital health and expanding infrastructure for affordable access to high-quality internet are essential. Despite the study's limitations arising from relying on literature research, it is anticipated that the findings can serve as foundational data for preemptive responses and provide insights into the direction of the government's digital health policy to enhance the healthcare rights of individuals with disabilities.