• IEIE Transactions on Smart Processing and Computing
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• 제6권1호
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• pp.60-65
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• 2017

Network virtualization enables us to make efficient use of resources in a physical network by embedding multiple virtual networks in the physical network. In this paper, we develop a prototype of a virtual network embedding system. Our system consists of OpenStack, which is an open source cloud service platform, and shell scripts. Because OpenStack does not provide a quality of service control function, we realize bandwidth reservation for virtual links by making use of the ingress policing function of Open vSwitch, which is a virtual switch used in OpenStack. The shell scripts in our system automatically construct the required virtual network on the physical network using the OpenStack command-line interface, and they reserve bandwidth for virtual links using the Open vSwitch command. Experimental evaluation confirms that our system constructs the requested virtual network and appropriately allocates node and link resources to it.

• 한국컴퓨터산업학회논문지
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• 제3권1호
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• pp.85-94
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• 2002

ATM(Asychronous Transfer Mode) 표준에서 제안된 EMRCA(Explicit Max_min Rate Control Algorithm) 스위치 방식은 ATM 네트워크에서 ABR(Available Bit Rate) 서비스 트래픽을 제어한다. ATM 네트워크의 ABR 서비스 분류는 다양한 링크 용량에 적용하기 위하여 피드백 제어 방식을 사용한다. VS/VD(Virtual Source/Virtual Destination) 기법은 다른 종단간 ABR 제어 루프를 격리된 루프들로부터 분리할 수 있도록 해준다. 피드백 지연과 내부적으로 폐쇄된 구간을 갖는 ABR 트래픽 제어는 처리량, 지연 그리고 지터 등을 고려한 ABR 접속에 있어서 보다 나은 성능과 QoS(Quality of Service)를 제공한다. 본 논문은 ABR VS/VD 흐름 제어 방식에 관한 연구이다. 매개변수를 정확하게 선택하고 시스템의 안정성과 같은 성능을 평가하는 수단을 제공하기 위하여 선형 제어 이론을 사용하여 모델링 하였다. 성능 개선의 목적은 높은 링크 이용율과 공정한 대역폭 분배 그리고 안정된 동작등이며 이는 이산 사건 시뮬레이션을 하였다. 본 논문에서는 VS/VD 스위치의 특수한 레이아웃에 맞춘 ABR 흐름 제어 방식의 설계에 선형 제어 이론을 사용한 것이며 시뮬레이션을 하여 기존의 폭주 제어 방식보다 우수함을 보였다.

• Asia pacific journal of information systems
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• 제13권3호
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• pp.1-21
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• 2003

Facing competitive and complicated business environment, many companies are developing new and diverse organization forms not only to overcome to minimize costs and risks but also to maximize the efficiency of an organization. Virtual organization is one of the representative forms allowing firms to create this value though a link of core competency among firms. In order to explain the performance of virtual organization in terms of efficiency, this study utilizes a concept of trust since it is recently considered as one of core concept to enhance the cooperative performance between firms and also virtual organizations success or failure can not be properly explained by traditional transaction-cost based economic point of view. Based on previous literature this study derives three success factors, organizational reputation, skill Uniqueness, and interpersonal trust and studies how three factors influence on the efficiency of virtual organization. Findings conducted with a questionnaire survey are as follow: first, organization reputation and skill uniqueness between virtual organization's transaction parties are important elements in the success of virtual organization. Second, interpersonal trust affected by organization reputation and skill uniqueness decides virtual organization's efficiency.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권1호
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• pp.145-164
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• 2014

Network virtualization provides a promising tool to allow multiple heterogeneous virtual networks to run on a shared substrate network simultaneously. A long-standing challenge in network virtualization is the Virtual Network Embedding (VNE) problem: how to embed virtual networks onto specific physical nodes and links in the substrate network effectively. Recent research presents several heuristic algorithms that only consider single topological attribute of networks, which may lead to decreased utilization of resources. In this paper, we introduce six complementary characteristics that reflect different topological attributes, and propose three topology-aware VNE algorithms by leveraging the respective advantages of different characteristics. In addition, a new KS-core decomposition algorithm based on two characteristics is devised to better disentangle the hierarchical topological structure of virtual networks. Due to the overall consideration of topological attributes of substrate and virtual networks by using multiple characteristics, our study better coordinates node and link embedding. Extensive simulations demonstrate that our proposed algorithms improve the long-term average revenue, acceptance ratio, and revenue/cost ratio compared to previous algorithms.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2008년도 정기 학술대회
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• pp.100-103
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• 2008

Recently Development of construction system that subjective operators share and control information efficiently based on the three-dimensional space and design information throughout life cycle of construction project is progressing dynamically. In case of civil structures which are infrastructure, Demand for structure of complex system which has multi-functions such as super and smart bridges and express rails is increasing and system development which computerizes and integrates process of structure design is in need. For that, research about link way between three dimensional modeling data and structure analysis programs should be preceded. In this research, therefore, research about interface design between three dimensional virtual modeling data to automate efficient civil-structure-design and nonlinear finite element analysis program which is made up of reinforced concrete material model that express material's character clearly.

• 대한기계학회논문집A
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• 제30권3호
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• pp.231-240
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• 2006

Immersive virtual reality (VR) for the manufacturing planning helps to shorten the planning times as well as to improve the quality of planning results. However, VR equipment is expensive, both in terms of development efforts and device. Engineers also spend time to manually repair erroneous 3-D shape because of imperfect translation between 3-D engineering CAD model and VR system format. In this paper a method is proposed to link 3-D engineering CAD model to a multichannel visualization system with PC clusters. The multichannel visualization module enables distributed computing for PC clusters, which can reduce the cost of VR experience while offering high performance. Each PC in a cluster renders a particular viewpoint of a scene. Scenes are synchronized by reading parameters from the master scene control module and passing them to client scenes.

• 대한전기학회논문지:시스템및제어부문D
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• 제51권10호
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• pp.439-445
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• 2002

In this paper force feedback control system is investigated for improving the quality of the haptic feedback in virtual reality applications. We suggested the method of controlling the haptic device and modelling the virtual environment. Haptic device is composed of five bar link structure, voice coil motor, control board, and virtual environment modeling program. We applied voice coil motor in the actuating system for simple structure and easy control. Virtual environment modelling is constructed in PC, and the control signals of the actuators and the encoder data are transferred to the control system through USB. Experiment is performed to evaluate the characteristics of the haptic device.

• 한국컴퓨터정보학회논문지
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• 제11권2호
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• pp.177-186
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• 2006

이 논문은 입력 영상에 대해 기존의 영상기반 렌더링 기법을 적용하고 가상공간지도라는 개념을 도입하여 사실적인 3차원 가상공간을 구축할 수 있는 효율적인 저작도구 개발에 대한 연구를 기술하고 있다. TIP 같은 기존의 기법들은 단일 영상을 사용하여 작은 3D가상공간을 구축하는 반면 여기서 제안하는 저작도구는 복수의 영상을 사용하여 광범위한 가상공간을 구축한다. 이 저작도구는 입력영상 각각에 대해 작은 3차원 가상공간을 구축하고 먼저 정의된 가상공간지도를 사용하여 이 독립적인 3D가상공간을 서로 연결하여 광범위한 3D가상공간을 구축할 수 있게 설계되었다. 가상공간지도는 세 가지 구성요소와 세 가지 방향으로 구성되어있다. 세 가지 구성요소는 특정 공간, 연결점 및 통로이고, 세 가지 방향은 정방향, 역방향 및 양방향이다. 가상공간지도는 가상공간의 연결구조, 네비게이션 정보 등 다양한 정보를 가지고 있다. 또한 이 저작도구는 사용자가 광범위한 3차원 가상공간을 쉽게 구축할 수 있게끔 사용자 인터페이스를 제공하고 있다.

• 한국CDE학회논문집
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• 제16권4호
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• pp.305-313
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• 2011

This paper proposes a method for reusing kinematic design data for virtual facilities, Making a virtual model of a facility involves two major activities: geometric design (virtual model visualization) and kinematic design that should be remodeled frequently whenever design changes occur, Conventionally, a virtual model of an automated facility focuses on the design level, which mainly deals with design verification, alternative comparison, and geometric model diagnosis, Although a design level model can be designed with the information of past models from PLM system, a simulation level model is not sufficient utilized to be reused for kinematic design purpose, We propose a method for reusing kinematic information of a past simulation model to cope with this problem, We use the concept or the 'center of mass', which is a point representing the mean position of the matter in a body or system. And we also use comparison method of a boundary box to identity which 3D objects have to be involved from the design model to a link structure that is contained in the simulation model. Because a proposed method only use not a historical approach but a geometrical approach, it is more effective to apply to the field.

• 한국통신학회논문지
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• 제39B권8호
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• pp.491-498
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• 2014

현재의 인터넷은 경직성으로 인해 새로운 서비스 요구를 수용하기 어렵다. 이러한 문제를 해결하기 위한 방안중 하나가 네트워크 가상화다. 본 논문에서는 네트워크 가상화를 위한 휴리스틱 가상 네트워크 대응 방안을 제안한다. 제안하는 방안에서는 가상 네트워크를 실제 네트워크에 대응시킬 때, 실제 노드가 가상 링크 조건을 만족시킬 수 있는 가능성이 있는 지 확인하고 가상 노드와 실제 노드에 우선순위를 부여하여 우선순위에 따라 대응 순서를 정한다. 또한 대응되는 실제 노드가 클러스터를 형성할 수 있도록 한다. 제안하는 방안의 성능을 시간 복잡도와 가상 네트워크 수락율로 평가한다.