• 한국멀티미디어학회논문지
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• 제8권1호
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• pp.119-127
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• 2005

국내의 많은 대학들은 매년 교육전산망에서 망 서비스 업자를 공개 입찰로 선정한 결과에 따라 교내망을 자신에 맞게 다양한 방법으로 외부망과 연결시키고 있다 그런데 이들 중 특히, 여러 외부망을 연동시키는 대학에서는 연동 비율에 따라서 전산망 운영 방식을 결정하는데 있어 보다 복잡한 문제에 부딪치고 있다. 따라서 이러한 대학들은 자신의 전산망 운영 방식을 보다 적합하게 결정할 수 있는 지원체계가 시급하다. 본 논문은 전국의 대학전산망 운영자를 대상으로 한 트래픽 관리에 대한 설문조사를 바탕으로 하여 회선 이용율에 기반한 트래픽 효율성을 분석하였다. 그리고 이를 이용하여 두 사업자를 동시에 채택하고 있는 대학의 효율적인 외부망 연동 전략 방안을 제시한다.

• 한국멀티미디어학회논문지
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• 제7권1호
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• pp.64-72
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• 2004

인터넷의 광범위한 사용과 더불어 이동성은 컴퓨터 사용자들의 컴퓨팅 환경을 급격하게 변화시키고 있다. 이러한 인터넷 사용환경에서 이동성을 보장하기 위하여 IETF에서는 Mobile IP 프로토콜을 표준화하였다. Mobile IP 사용시 인터넷 사용자는 자신의 홈 네트워크에서 다른 외부 네트워크로 이동하더라도 IP 주소 설정의 변경 없이 자유롭게 인터넷을 사용할 수 있는 장점이 있다. 본 논문에서는 이러한 Mobile IP를 학내망에 도입하기 위하여 그 성능을 평가하기 위한 테스트베드를 구축한다. Mobile IP 프로토콜의 사용이 네트워크 성능에 미칠수 있는 영향을 실험적으로 평가함으로써 학내 망에 직접 설치하여 검증할 때 발생 가능한 부작용을 줄일 수 있을 것으로 예상된다.

• 한국항행학회논문지
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• 제21권5호
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• pp.472-478
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• 2017

본 논문에서는 네트워크 토폴로지 설계방법들(minimum spanning tree와 Dijkstra algorithm)을 사용하여 교통 격자 가로망을 최적화 하는 방안을 다루며, 최소신장트리(minimum spanning tree)에서 직진 교통신호등간의 연동들을 통해 출발지와 목적지간의 지연시간을 최소화 하는 것으로 교통격자 가로망을 최적화한다. 또한 컴퓨터 네트워크에서 사용되어지는 Dijkstra algorithm을 통해 구해진 경로에 따라 차량 운전자들이 그 경로를 준수한다고 가정한다면 격자망에서 교통신호등의 연동을 통해 최적화할 수 있음을 보여준다. 격자 가로망에서의 모의실험결과는 직진 교통신호등의 연동을 통해 망을 가로지는 지연시간을 최소화함을 보여준다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권3호
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• pp.1034-1051
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• 2016

Mobility models are invaluable for determining the performance of routing protocols in opportunistic networks. The movement of nodes has a significant influence on the topological structure and data transmission in networks. In this paper, we propose a new mobility model called the campus-based community mobility model (CBCNM) that closely reflects the daily life pattern of students on a real campus. Consequent on a discovery that the pause time of nodes in their community follows a power law distribution, instead of a classical exponential distribution, we abstract the semi-Markov model from the movement of the campus nodes and analyze its rationality. Then, using the semi-Markov algorithm to switch the movement of the nodes between communities, we infer the steady-state probability of node distribution at random time points. We verified the proposed CBCNM via numerical simulations and compared all the parameters with real data in several aspects, including the nodes' contact and inter-contact times. The results obtained indicate that the CBCNM is highly adaptive to an actual campus scenario. Further, the model is shown to have better data transmission network performance than conventional models under various routing strategies.

• Journal of Electrical Engineering and Technology
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• 제13권1호
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• pp.521-531
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• 2018

This paper presents a procedure for field measurements which provides a generalized Narrowband Power Line Communications (NB-PLC) channel model for low voltage (LV) access network in order to deploy advanced metering infrastructure (AMI) within Lahore, Pakistan. The measurements of allocated sites were performed in the residential (urban and rural), industrial and commercial electricity consumers for the NB-PLC channel modeling of overhead transmission lines (TLs). On the basis of extensive field measurement results, the average attenuation profile and transfer functions are presented. The results obtained from field measurements are validated by comparing them with a proposed Simulink model. A close agreement in the measured and simulated transfer function (TF) results is observed. The proposed Simulink model is an effort to model the NB-PLC channels in an effective way, especially in South Asian countries.

• International Journal of Computer Science & Network Security
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• 제23권8호
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• pp.146-158
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• 2023

Smart City is gaining attention with the advancement of Information and Communication Technology (ICT). ICT provides the basis for smart city foundation; enables us to interconnect all the actors of a smart city by supporting the provision of seamless ubiquitous services and Internet of Things. On the other hand, Crowdsourcing has the ability to enable citizens to participate in social and economic development of the city and share their contribution and knowledge while increasing their socio-economic welfare. This paper proposed a hybrid model which is a compound of human computation, machine computation and citizen crowds. This proposed hybrid model uses knowledge-based crowdsourcing that captures collaborative and collective intelligence from the citizen crowds to form democratic knowledge space, which provision solutions in areas of civic innovations. This paper also proposed knowledge-based crowdsourcing framework which manages knowledge activities in the form of human computation tasks and eliminates the complexity of human computation task creation, execution, refinement, quality control and manage knowledge space. The knowledge activities in the form of human computation tasks provide support to existing crowdsourcing system to align their task execution order optimally.

• 한국인터넷방송통신학회논문지
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• 제18권6호
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• pp.33-41
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• 2018

스마트 캠퍼스의 플랫폼으로 사물 인터넷에 대한 아이디어가 점점 대중화되고 있다. 인터넷에 연결하기 위해 통신 네트워크, 센서 노드 및 게이트웨이로 구성된 인프라가 필요하며 각 센서 노드는 환경에서 데이터를 수집할 수 있다. 본 논문은 스마트 캠퍼스 모니터링을 적용하기 위해 인터넷에 구성한 무선 센서 네트워크를 설명한다. 무선 센서 네트워크 모니터링은 저전력 구현 및 통합 시스템을 사용하는 완벽한 솔루션이다. 그러나 제한된 컴퓨팅 범위, 제한된 컴퓨팅 성능, 네트워크 프로토콜의 가용성 부족, 프로그래밍 보안 부족 및 기밀성, 무결성 및 가용성 분야의 보안 오류로 인해 수많은 제약이 있다. WSNM 노드를 위한 새로운 보안 기술과 기능이 개발되었다. 보안 네트워크 연구 개발 및 서비스 거부 (DOS) 및 복잡성 공격 방지를 위한 시스템을 제안하였다. 이러한 시스템이 제대로 구현되면 사전 할당을 통한 에너지 효율성 메커니즘과 안전한 루틴 알고리즘을 통해 핵심 관리 모델의 새로운 키를 제공 할 수 있다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권12호
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• pp.4682-4705
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• 2020

The Unmanned Aerial Vehicles (UAV) networks consisting of low-cost UAVs are very vulnerable to smart jammers that can choose their jamming policies based on the ongoing communication policies accordingly. In this article, we propose a novel cloud and edge-aided mobile communication scheme for low-cost UAV network against smart jamming. The challenge of this problem is to design a communication scheme that not only meets the requirements of defending against smart jamming attack, but also can be deployed on low-cost UAV platforms. In addition, related studies neglect the problem of decision-making algorithm failure caused by intermittent ground-to-air communication. In this scheme, we use the policy network deployed on the cloud and edge servers to generate an emergency policy tables, and regularly update the generated policy table to the UAVs to solve the decision-making problem when communications are interrupted. In the operation of this communication scheme, UAVs need to offload massive computing tasks to the cloud or the edge servers. In order to prevent these computing tasks from being offloaded to a single computing resource, we deployed a lightweight game algorithm to ensure that the three types of computing resources, namely local, edge and cloud, can maximize their effectiveness. The simulation results show that our communication scheme has only a small decrease in the SINR of UAVs network in the case of momentary communication interruption, and the SINR performance of our algorithm is higher than that of the original Q-learning algorithm.

• Architectural research
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• 제9권1호
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• pp.19-30
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• 2007

This study explores the issue of campus expansion of an urban university using an in-depth case study of New York University in New York City, USA. It investigates the physical pattern and development mechanism of the campus expansion process on a city grid structure. The three elements that characterize NYU's recent campus expansion, are (1) the university's commitment to building a student community around a public open space on a subway network, (2) four types of property acquisition and building development practiced by the university with private developers for space leasing, building renovation and development under changing local development circumstances, and (3) the city's initiative for attracting the private sector whose development activities influence the university's development dynamics. These findings suggest that the expansion planning of an urban university, due to its location in a city, should be placed on a local planning agenda, which can positively contribute to public goals through the collaborative engagement of the private and public sectors.

• IMMUNE NETWORK
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• 제20권4호
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• pp.30.1-30.10
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• 2020

Systemic infections due to Fusobacterium may originate in the tonsillar/internal jugular veins or from the abdomen. We encountered a patient who presented with bacteremia, fulminant septic shock, and extensive soft tissue pyogenic infection due to Fusobacterium necrophorum. In addition, there was widespread metastatic colon cancer with the unique finding of pre-mortem co-localization of F. necrophorum and cancer cells at a site distant from the colon. We reviewed the literature of the association of F. necrophorum and colon cancer, and discuss the evidence of how each of these 2 distinct entities may mutually augment the development or progression of the other.