• International Journal of Computer Science & Network Security
• /
• 제22권11호
• /
• pp.241-247
• /
• 2022

Ad hoc network is self-organized network powered by battery. The reliability of virtual user identification and channel security are reduced when SNR is low due to limited user energy. In order to solve this problem, a joint virtual user identification and channel security en/decoding method is proposed in this paper. Transmitter-receiver-based virtual user identification code is generated by executing XOR operation between orthogonal address code of transmitter and pseudo random address code of receiver and encrypted by channel security code to acquire orthogonal random security sequence so as to improve channel security. In order to spread spectrum as well as improve transmission efficiency, data packet is divided into 6-bit symbols, each symbol is mapped with an orthogonal random security sequence. Subspace-based method is adopted by receiver to process received signal firstly, and then a judgment model is established to identify virtual users according to the previous processing results. Simulation results indicate that the proposed method obtains 1.6dB E_b/N₀ gains compared with reference methods when miss alarm rate reaches 10^-3.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2002년도 ICCAS
• /
• pp.121.6-121
• /
• 2002

Web-based virtual machine/manufacturing system (VMS) utilizes Virtual Device Network (VDN.) VDN inevitably involves the implementation of Distributed Monitoring and Control Networks (DMCN). In general, one needs to integrate device (control) network and IP network to realize DMCN over IP network or internet, which can be viewed as a VDN. In this study, LonWorks networking technology is used for device network and the transmission characteristics of LonWorks/IP-based VDN is investigated. A method to minimize the transmission delay in the LonWorks/IP networks is also suggested.

• ETRI Journal
• /
• 제37권2호
• /
• pp.369-379
• /
• 2015

Fault management of virtualized network environments using user-driven network provisioning systems (NPSs) is crucial for guaranteeing seamless virtual network services irrespective of physical infrastructure impairment. The network service interface (NSI) of the Open Grid Forum reflects the need for a common standard management API for the reservation and provisioning of user-driven virtual circuits (VCs) across global networks. NSI-based NPSs (that is, network service agents) can be used to compose user-driven VCs for mission-critical applications in a dynamic multi-domain. In this article, we first attempt to outline the design issues and challenges faced when attempting to provide mission-critical applications using dynamic VCs with a protection that is both user-driven and trustworthy in a dynamic multi-domain environment, to motivate work in this area of research. We also survey representative works that address inter-domain VC protection and qualitatively evaluate them and current NSI against the issues and challenges.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2004년도 추계학술대회 논문집
• /
• pp.1253-1258
• /
• 2004

A general idea of implementing and managing real-time control on the VDN for rail transit vehicles is presented. In particular, the virtual device network considered in this paper is composed of Ethernet as the data network and LonWorks network as the device (control) network. A LonWorks/IP web server was used as a gateway to realize peer to peer data communication on the virtual device networks. Experimental results are given to validate the suggested architecture.

• 한국정보처리학회:학술대회논문집
• /
• 한국정보처리학회 2012년도 춘계학술발표대회
• /
• pp.590-593
• /
• 2012

현재 인터넷은 하드웨어 종속적인 특징을 가지고 있어 급변하는 환경에 적응하기 힘들다. 이러한 제약사항은 관련 산업 발전을 더디게 하고 있다. 이와 같은 네트워크 환경에서 산업 발전을 위하여 네트워크 인프라에 유연성을 제공할 수 있는 기술의 개발이 필요하다. 그러한 문제를 해결하기 위해 오픈프로토콜인 OpenFlow의 Programmable Network의 특성을 이용하여 네트워크 가상화를 구현하였으며, 응용 서비스별 Virtual Network를 제공하는 방안에 대해 연구하였다. 이를 위하여 OpenFlow 기반의 Programmable Network를 구축하였으며, 동적으로 구성이 가능한 네트워크에서 가상화를 제공하기 위해 VNAPI를 개발하였다. 또한, VNAPI를 통하여 신뢰성 있고 효율적인 응용 서비스의 전달을 위하여 Virtual Network Topology에 대한 설계를 같이 수행하였다.

• 한국정보통신학회:학술대회논문집
• /
• 한국해양정보통신학회 2009년도 추계학술대회
• /
• pp.793-794
• /
• 2009

최근에는 컴퓨팅 자원이 크게 증가하여, 인터넷을 통해 연결된 수많은 컴퓨팅 자원들을 다수의 사용자가 이용하고 어떻게 서비스 할 것인가에 대한 클라우드 컴퓨팅 또는 그리드 컴퓨팅 기술이 주목받고 있으며 또한 네트워크에서도 물리적 네트워크 위에 가상의 네트워크 링크와 노드을 구성하여 가상의 네트워크를 구성하는 가상 네트워크 환경 연구가 이뤄지고 있다. 가상화 기술은 네트워크 보다는 실질적으로 운영체제 분야에서 오랫동안 연구되고 발전되고 있으나 본 논문에서는 네트워크 분야에 적용된 가상화기술을 토대로 모바일 네트워크에 적용된 가상 모바일 네트워크에 대하여 살펴보도록 하겠다.

• 유통과학연구
• /
• 제17권3호
• /
• pp.85-95
• /
• 2019

Purpose - The existing marketing studies using Social Network Analysis have assumed that network structure variables are time-invariant. However, a node's network position can fluctuate considerably over time and the node's network structure can be changed dynamically. Hence, if such a dynamic structural network characteristics are not specified for virtual goods purchase model, estimated parameters can be biased. In this paper, by comparing a time-invariant network structure specification model(base model) and time-varying network specification model(proposed model), the authors intend to prove whether the proposed model is superior to the base model. In addition, the authors also intend to investigate whether coefficients of network structure variables are random over time. Research design, data, and methodology - The data of this study are obtained from a Korean social network provider. The authors construct a monthly panel data by calculating the raw data. To fit the panel data, the authors derive random effects panel tobit model and multi-level mixed effects model. Results - First, the proposed model is better than that of the base model in terms of performance. Second, except for constraint, multi-level mixed effects models with random coefficient of every network structure variable(in-degree, out-degree, in-closeness centrality, out-closeness centrality, clustering coefficient) perform better than not random coefficient specification model. Conclusion - The size and importance of virtual goods market has been dramatically increasing. Notwithstanding such a strategic importance of virtual goods, there is little research on social influential factors which impact the intention of virtual good purchase. Even studies which investigated social influence factors have assumed that social network structure variables are time-invariant. However, the authors show that network structure variables are time-variant and coefficients of network structure variables are random over time. Thus, virtual goods purchase model with dynamic network structure variables performs better than that with static network structure model. Hence, if marketing practitioners intend to use social influences to sell virtual goods in social media, they had better consider time-varying social influences of network members. In addition, this study can be also differentiated from other related researches using survey data in that this study deals with actual field data.

• 디지털융복합연구
• /
• 제14권10호
• /
• pp.303-310
• /
• 2016

인터넷의 경직성으로 인하여 다양한 서비스를 제공하기 어려운 문제를 해결하기 위한 가장 효과적인 방법이 네트워크 가상화 방안이다. 공통의 물리 네트워크 자원을 공유하는 가상 네트워크를 효율적으로 생성하기 위해서는 자원을 효율적으로 사용할 수 있는 방안이 필요하다. 이러한 한정된 물리 자원을 효율적으로 사용하기 위하여 본 논문에서는 사용중인 자원이라도 더 높은 서비스 우선순위를 갖는 가상 네트워크에 할당하는 방법을 제안한다. 높은 우선순위의 네트워크 생성 요청을 위하여 운용중인 낮은 우선순위의 가상 네트워크에서 효율적으로 대역폭을 회수하는 알고리즘을 제안한다. 제안하는 대역폭 할당 알고리즘은 낮은 우선순위를 갖는 가상 네트워크에서 서비스 지속성을 유지하면서 할당된 대역폭을 회수할 수 있다. 제안한 알고리즘의 실험을 통하여 약 8%정도의 가상 네트워크 생성 수락률의 향상을 확인하였다.

• Management Science and Financial Engineering
• /
• 제12권2호
• /
• pp.37-62
• /
• 2006

This paper considers the problem of designing logical tunnels in virtual private networks considering QoS guarantee which restricts the number of tunnel hops for each traffic routing. The previous researches focused on the design of logical tunnel itself and Steiner-tree based solution algorithms were proposed. However, we show that for some objective settings it is not sufficient and is necessary to consider both physical and logical connectivity at the same time. Thereupon, the concept of the layered network is applied to the logical tunnel design problem in virtual private networks. The layered network approach considers the design of logical tunnel as well as its physical routing and we propose a modified branch-and-price algorithm which is known to solve layered network design problems effectively. To show the performance of the proposed algorithm, computational experiments have been done and the results show that the proposed algorithm solves the given problem efficiently and effectively.

• 한국정보시스템학회지:정보시스템연구
• /
• 제31권2호
• /
• pp.19-43
• /
• 2022

Purpose Due to the COVID-19 pandemic, many companies are building virtual workplaces based on virtual reality technology. Through this study, we intend to identify the trend of convergence and convergence research between virtual reality technology and work space, and suggest future promising fields based on this. Design/methodology/approach For this purpose, 12,250 bibliographic data of research papers related to Virtual Reality (VR) and Workplace were collected from Scopus from 1982 to 2021. The bibliographic data of the collected papers were analyzed using Text Mining and Pathfinder Network, Parallel Neighbor Clustering, Nearest Neighbor Centrality, and Triangle Betweenness Centrality. Through this, the relationship between keywords by period was identified, and network analysis and visualization work were performed for virtual reality-based workplace research. Findings Through this study, it is expected that the main keyword knowledge structure flow of virtual reality-based workplace convergence research can be identified, and the relationship between keywords can be identified to provide a major measure for designing directions in subsequent studies.