지연 감내 네트워크에서 커뮤니티 기반 영향력 측정 기법

김찬명(Chan-Myung Kim),김용환(Yong-hwan Kim),한연희(Youn-Hee Han) 한국통신학회 2013 韓國通信學會論文誌 Vol.38 No.1B

사회 관계망에서 영향력의 전파는 중요한 연구 이슈이다. 영향 전파는 임의의 노드로 부터 새로운 아이디어, 정보, 소문의 전파로 인해 다른 노드들의 상태나 성질이 변화하는 것을 뜻한다. 영향을 받은 노드는 자신과 통신하는 다른 노드에게도 영향을 주고 영향은 확산되어 네트워크 내에서 퍼져 나간다. 입소문 마케팅에 기반을 둔 영향력 전파 문제는 네트워크에 가장 영향력을 끼칠 수 있는 노드들을 찾아 전체 네트워크에 영향력을 최대화 하는 것이 목적이다. 본 논문에서는 Delay-Tolerant Networks에서 각 노드의 영향력을 측정하여 가장 영향력 있는 노드 집합을 선택하는 문제를 다룬다. 노드 간 연결성이 항시 보장되지 않는 Delay-Tolerant Networks 환경에서는 전체 네트워크 정보를 정확히 알 수 없기 때문에 노드의 영향력을 정확히 측정하는 것은 쉽지 않다. 본 논문에서는 Delay-Tolerant Networks 환경에서 분산 방식으로 각자 노드가 κ-clique 구조로 커뮤니티를 구성하여 한정된 지역 정보만을 활용하여 자신의 영향력을 추정하는 방법을 제시한다. 또한, 실험을 통해 제안 기법으로 산출한 영향력 있는 노드 정보가 전체 네트워크 관점에서 산출한 영향력 있는 노드 정보와 거의 일치함을 보인다. Influence propagation is an important research issue in social networks. Influence propagation means that the status or the disposition of nodes get changed by new idea, information and gossip propagated by other nodes. Influenced nodes also make other nodes influenced across the network. The influence propagation problem based on ‘word of mouth’ referral is to find most influential nodes set in networks to maximize influence. In this paper, we study the influence measuring and finding most influential nodes set in Delay-Tolerant Networks. It is difficult to measure exact influential power in Delay-Tolerant networks where network topology is not stable due to the nodal mobility. In this paper, we propose a distributed scheme that each node constructs κ-clique community structure and estimates local influential power in Delay-Tolerant Networks. Simulation results show that the influential nodes information estimated by proposed scheme is in agreement with a global view of influential nodes information.

행성 간 통신에서의 지연/분열 허용 네트워크 성능 분석

백재욱,한상익,김인규 사단법인 한국위성정보통신학회 2017 한국위성정보통신학회논문지 Vol.12 No.4

Delay- and Disruption-Tolerant Network (DTN) has been considered as a key technology to overcome main challenges in interplanetary communications such as an intermittent connectivity and high bit error rates. The lack of end-to-end connectivity between source and destination results in long and variable delays and data loss, hence the Internet Protocols cannot operate properly in such environments because it requires an end-to-end connectivity. The DTN, which utilizes ‘store-and-forward’ message passing scheme between nodes, can overcome the lack of end-to-end connectivity in Interplanetary Network (IPN). In this paper, DTN is applied to 3-hop relay IPN, where messages are transmitted from Earth ground station to Lunar lander through Earth satellite and Lunar orbiter. ONE simulator is used to reflect the real environment of IPN and an efficient resource management method are analyzed to guarantee the message delivery by optimizing a message TTL (Time to Live), buffer size and message fragmentation. 지연/분열 허용 네트워크는 간헐적인 통신링크 단절, 높은 전송 에러율와 같은 행성 간 통신에서 마주하는 주된 문제점들을 해결할주된 기술로 여겨진다. 행성 간 통신에서 종단간 연결성이 보장되지 않아 간헐적으로 통신링크가 단절되면 길고 일정하지 않은 시간지연과 정보 손실이 발생하고, 따라서 종단간 연결성을 요구하는 인터넷 프로토콜은 행성 간 통신에 적합하지 않다. Store-and-forward 메시지 전송 방식을 따르는 지연/분열 허용 네트워크는 행성 간 통신에서 종단간 연결성이 보장되지 않아 발생하는 문제점을 해결할 수 있다. 본 논문에서는 지구 기지국-지구 위성-달궤도선-달탐사체로 구성된 3-hop 릴레이 우주통신 환경에지연/분열 허용 네트워크 개념을 적용한 통신 모델을 제시하며, ONE 시뮬레이터를 이용한 실제 우주통신환경 모델링 및 성능 분석을 통해, 안정적인 메시지 전송을 보장하는 최적의 메시지 수명, 버퍼 공간 및 메시지 분할 방법을 제시한다.

달 탐사선과 지상국간 지연 인지 데이터 통신 프로토콜 접속 연구

구철회,김창균,류동영 한국항공우주학회 2015 한국항공우주학회 학술발표회 논문집 Vol.2015 No.4

달의 자전과 공전, 그리고 지구와 약 40만 km 떨어져 있는 달 탐사선의 정확한 자세 및 궤도 정보의 부재는 달탐사선과 지상국간 신뢰성있는 통신 채널의 지속적 유지에 대한 예측을 어렵게 하고 있다. 통신이 끊길 때 재개되기까지 수분에서 수시간까지 지연이 나타날 수 있고 이는 데이터 전송에 심각한 지장을 초래할 수 있다. 이와 같은 달탐사선과 지상국과의 통신 환경은 TCP와 같은 지상 인터넷 통신 프로토콜로도 해결할 수 없는 문제이고 해외 우주탐사 선진국에서는 지연허용 네트워크(DTN) 프로토콜을 통해 극복하고 있다. 현재 추진중인 한국형 달탐사 개발사업에서도 최소한 지연을 인지한 데이터 통신 프로토콜 접속 방안에 대한 연구가 요구되고 있다. 본 논문에서는 지금까지 지연을 고려했을 때 달 탐사선과의 지상국간 적합한 데이터 통신 프로토콜에 대한 연구한 내용을 정리하였다. Estimation of reliable communication channel between lunar orbiter and ground station is difficult due to Moon’s rotation and revolution, and ambiguity of attitude and orbit information of lunar orbiter which orbits Moon around 400,000 km away from Earth. Delay may exist during several minutes or hours until next communication is reestablished, and it severly affects on reliable data transmission. Even TCP which is stable protocol for ground internet environment can’t be used for solving this problem, so abroad developed space explorer country uses delay tolerant network (DTN) for the solution of this delay. At the result at least delay cognitive data communication protocol is being considered at Korean Lunar Explorer project as planning phase. In this paper, a study of appropriate data communication protocol between lunar explorer and ground station provided that consideration of delay is summarized.

Performance Evaluation of Efficient Routing Protocols in Delay Tolerant Network under Different Human Mobility Models

Namita Mehta,Mehul Shah 보안공학연구지원센터 2015 International Journal of Grid and Distributed Comp Vol.8 No.1

Delay and/or Disruption-Tolerant Networking (DTN) is a novel communication prototype that can span across multiple networks and deal with unpredicted conditions in the Internet model.Delay-tolerant networks (DTNs) are partitioned wireless ad hoc networks with intermittent connectivity. Additional terminology in this family of dynamic networks includes disruption-tolerant networks, intermittently connected networks, and opportunistic networks. Routing of the packets in DTN is based on store-carry-and forward paradigm. In this paper, we study and analyze performance of well known PROPHET and Spray and Wait routing protocol, under different human mobility models such as Truncated Levy Walk mobility model (TLW),Self-similar Least Action Walk (SLAW) and Random way point (RWP) model. The MATLAB simulator is used in order to analyze the performance of these routing protocols.Simulation results illustrate that Spray and Wait significantly outperforms the PROPHET on aspects of delivery ratio, average delay and communication overhead.

지연 감내 네트워크에서 사회관계기반 기회적 라우팅 기법

최재인 ( Jae In Choi ),박인수 ( In Soo Park ),조유제 ( You Ze Cho ) 한국정보처리학회 2014 정보처리학회논문지. 컴퓨터 및 통신시스템 Vol.3 No.1

Delay-Tolerant Network employs message forwarding based on a Store, Carry and Forward method to conquer no guarantee of continue connectivity. For this reason, a lot of DTN routing scheme have been proposed recently. message forwarding is an important research issue in delay-tolerant network and In this paper, we propose a efㄴficiency DTN routing scheme using node`s social relation and expanded Ego-network betweenness centrality. Our simulation results show that it is more efficient to message delivery cost than Epidemic routing, Friendship routing while it has a little performance degradation of message delivery ratio.

Delay Tolerant Network에서 효율적인 메시지 전달을 위한 라우팅 프로토콜 연구

장성진,신용태,김종배 한국통신학회 2013 韓國通信學會論文誌 Vol.38 No.2(융합기술)

Delay Tolerant Network(DTN)은 통신 인프라가 임시적이고 간헐적인 모바일 노드의 연결에 의하여 디자인 되어졌다. 이 네트워크는 노드가 전송범위 안에 다른 노드를 만났을 때 노드의 메시지를 버퍼에 저장하고 이동 중에 전달하는 store-carry-forward 방법으로 동작한다. 전통적인 통신방법인 TCP/IP 기반의 네트워크는 노드가 움직일 때 잦은 토폴로지 변화, 분열 그리고 네트워크 단절로 인하여 종단간의 연결을 지원하지 못한다. 이 논문에서는 DTN 라우팅 프로토콜에서 효과적인 메시지 전달을 위한 버퍼관리 기법과 라우팅 방법을 제안한다. 시뮬레이션 결과에서는 기존보다 효과적인 라우팅 밥법을 제시한다

Proposed Message Transit Buffer Management Model for Nodes in Vehicular Delay-Tolerant Network

Gballou Yao, Theophile,Kimou Kouadio, Prosper,Tiecoura, Yves,Toure Kidjegbo, Augustin International Journal of Computer ScienceNetwork S 2023 International journal of computer science and netw Vol.23 No.1

This study is situated in the context of intelligent transport systems, where in-vehicle devices assist drivers to avoid accidents and therefore improve road safety. The vehicles present in a given area form an ad' hoc network of vehicles called vehicular ad' hoc network. In this type of network, the nodes are mobile vehicles and the messages exchanged are messages to warn about obstacles that may hinder the correct driving. Node mobilities make it impossible for inter-node communication to be end-to-end. Recognizing this characteristic has led to delay-tolerant vehicular networks. Embedded devices have small buffers (memory) to hold messages that a node needs to transmit when no other node is within its visibility range for transmission. The performance of a vehicular delay-tolerant network is closely tied to the successful management of the nodes' transit buffer. In this paper, we propose a message transit buffer management model for nodes in vehicular delay tolerant networks. This model consists in setting up, on the one hand, a policy of dropping messages from the buffer when the buffer is full and must receive a new message. This drop policy is based on the concept of intermediate node to destination, queues and priority class of service. It is also based on the properties of the message (size, weight, number of hops, number of replications, remaining time-to-live, etc.). On the other hand, the model defines the policy for selecting the message to be transmitted. The proposed model was evaluated with the ONE opportunistic network simulator based on a 4000m x 4000m area of downtown Bouaké in Côte d'Ivoire. The map data were imported using the Open Street Map tool. The results obtained show that our model improves the delivery ratio of security alert messages, reduces their delivery delay and network overload compared to the existing model. This improvement in communication within a network of vehicles can contribute to the improvement of road safety.

우주인터넷과 Delay/Disruption Tolerant Netwoking (DTN) 프로토콜 개발 동향

박주호(Park, Joo-Ho),허윤구(Huh, Yun-Goo),채동철(Chae, Dong-Chul),김영윤(Kim, Young-Yun),조승원(Cho, Seung-Won),류진영(Ryu, Jin-Yeong),유명종(Yu, Myoung-Jong),문귀원(Moon, Guee-Won) 한국항공우주연구원 2015 항공우주산업기술동향 Vol.13 No.1

과거 소수 선진국만의 영역으로 여겨졌던 우주개발은 점차 다양한 국가들이 참여하는 양상을 띄고 있으며, 그 경쟁 또한 치열해지고 있다. 게다가, 국가주도의 우주개발 외에 민간기업들의 우주개발이 두드러지면서, 비즈니스 영역으로써 우주를 활용하려는 움직임도 보이고 있다. 최근 우주인터넷이라는 새로운 사업계획을 발표하며 또다시 세상의 주목을 받고 있는 스페이스 엑스(Space X)가 그 대표적인 예이다. 사실, 우주인터넷이라는 용어는 미국항공우주국(NASA) 및 유럽우주국(ESA)에서 심우주 탐사를 위한 네트워크 개념으로서 이미 사용된 바 있으며, 민간의 우주인터넷과는 개념적으로 다소 차이가 있다. 본 논문에서는 민간에서 추진중인 우주인터넷 계획과 주요 우주선진국의 우주인터넷 개념을 각각 살펴보았으며, Delay/Disruption Tolerant Networking (DTN)기술을 소개하고 그 개발동향을 기술하였다. In the past, just a few advanced countries led in field of space. Recently, however, more and various countries take part in this field and even many private companies expand their business boundary into the space. Early this year, Elon Musk, CEO at Space X, announced new project "Space Internet". National Aeronautics and Space Administration(NASA) and European Space Agency(ESA) also use this term, somewhat different way, as a network for deep space communication technology. In this paper, Space Internet of private company and national agency is described. Delay/Disruption Tolerant Networking (DTN) and related experiments are introduced as well.

Performance analysis of information propagation in DTN-like scale-free mobile social network

( Zhifei Wang ),( Su Deng ),( Hongbin Huang ),( Yahui Wu ) 한국인터넷정보학회 2014 KSII Transactions on Internet and Information Syst Vol.8 No.11

Mobile social network can be seen as a specific application of the DTN (Delay Tolerant Network), in which the information propagation can be impacted by many social behaviors of the nodes. For a specific node, its social behaviors are various. For example, the node may not be interested in the information before receiving it and may also discard the information after getting it. On the other hand, people are more willing to forward the message to his friends. These interactive behaviors between nodes can be seen as social behaviors. It is easy to see that the impact of the social behaviors is related to the social ties, which can be manifested by the structure of the social network. State of the art works often simply assumes that the social networks can be divided into some communities. At present, some works find that the structure of some social networks is scale-free. To overcome this problem, this paper proposes a theoretical model to evaluate the impact of above social behaviors in the DTN-like scale-free network. Simulation shows the accuracy of the model. Numerical results show that both social behaviors and scale-free character have significant impact on information propagation. Moreover, the impact of social behaviors is related to the scale-free character of the networks.

Performance Improvement of Delay-Tolerant Networks with Mobility Control under Group Mobility

( Ling Fu Xie ),( Peter Han Joo Chong ) 한국인터넷정보학회 2015 KSII Transactions on Internet and Information Syst Vol.9 No.6

This paper considers mobility control to improve packet delivery in delay-tolerant networks (DTNs) under group mobility. Based on the group structure in group mobility, we propose two mobility control techniques; group formation enforcement and group purposeful movement. Both techniques can be used to increase the contact opportunities between groups by extending the group`s reachability. In addition, they can be easily integrated into some existing DTN routing schemes under group mobility to effectively expedite the packet delivery. This paper is divided into 2 parts. First, we study how our proposed mobility control schemes reduce the packet delivery delay in DTNs by integrating them into one simple routing scheme called group-epidemic routing (G-ER). For each scheme, we analytically derive the cumulative density function of the packet delivery delay to show how it can effectively reduce the packet delivery delay. Then, based on our second proposed technique, the group purposeful movement, we design a new DTN routing scheme, called purposeful movement assisted routing (PMAR), to further reduce the packet delay. Extensive simulations in NS2 have been conducted to show the significant improvement of PMAR over G-ER under different practical network conditions.