• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2006년도 하계종합학술대회
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• pp.827-828
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• 2006

This paper presents a vehicle control algorithm for Personal Rapid Transit (PRT) system. PRT system is a one-way direction network system which is composed of guideway branches, merging/diverging points. Vehicle control algorithm can be divided into two kinds. Those are merging control algorithm and the other. We emphasized on the merging control algorithm. For that, we first devised a front/virtual front vehicle finding strategies. Properly determined front/virtual front vehicle is the starting point of vehicle control. The objects of merging control are to avoid collision and to pass the merging point fluently. Which implies that jerk constraint and limits of acceleration and deceleration etc. are should be considered. To verify the validation of the vehicle algorithm, we executed simulations and presented test results.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 추계학술대회 논문집
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• pp.27-30
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• 2000

In this paper, we determine the design criteria of haptic device considering the human haptic system and determine the design specifications. We developed a new 2DOF haptic device based on the specifications. It has the wide workspace, statically-balanced, constant inertia matrix, well-conditioned Jacobian matrix and so on. There also is not singularity point within workspace of the device. We show that it has better performance than other 2DOF haptic device in the many aspects.

• 한국컴퓨터그래픽스학회논문지
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• 제24권3호
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• pp.101-109
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• 2018

최근 가상 현실 및 증강 현실 기술의 발달로 다양한 형태의 기술이 제안되고 발전되고 있다. 특히 가상의 학습공간이나 가상의 건축 공간들을 위한 기술로서 원하는 형태의 그림을 그릴 수 있는 가상 드로잉 툴은 필수적인 요소 중 하나로 볼 수 있다. 기존의 래스터 기반 드로잉 알고리즘은 공간 이동이 잦은 가상 현실에서는 부적합 할 수 있는데, 가상 현실의 특성상 근접하거나 멀어지는 경우가 많기 때문이다. 본 논문에서는 연필 및 에어브러시의 물리적인 특성을 고려하여 실제 결과와 흡사하면서도 확대 및 축소에 강건한 가상의 드로잉 툴 렌더링 알고리즘을 제안한다. 캔버스로부터의 거리, 분사되는 잉크의 양, 움직이는 속도, 마찰력, 압력 등을 고려한다. 드로잉의 기본 단위는 정사각형 패치이며 각 패치는 슈도 랜덤값을 기반으로 하는 입자 형태의 이미지를 가진다. 이러한 입자 패치는 슈도 랜덤 식을 사용하고 매 프레임 마다 재 생성되기 때문에 확대 축소 시 깨짐 현상이 발생하지 않는다. 제안된 알고리즘은 2차원 환경 및 가상 현실 환경에 구현되었다. 2차원 환경은 안드로이드 기반 스마트폰에서 구현하였으며 가상 현실 환경은 언리얼 엔진 4를 사용하여 구현하였다. 구현 결과 확대 축소 시에도 이질감 없이 원래의 질감을 유지하는 렌더링 결과를 얻을 수 있었다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권3호
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• pp.1164-1183
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• 2019

The rapid development of cloud computing and high requirements of operators requires strong support from the underlying Data Center Networks. Therefore, the effectiveness of using resources in the data center networks becomes a point of concern for operators and material for research. In this paper, we discuss the online virtual-cluster provision problem for multiple tenants with an aim to decide when and where the virtual cluster should be placed in a data center network. Our objective is maximizing the total revenue for the data center networks under the constraints. In order to solve this problem, this paper divides it into two parts: online multi-tenancy scheduling and virtual cluster placement. The first part aims to determine the scheduling orders for the multiple tenants, and the second part aims to determine the locations of virtual machines. We first approach the problem by using the variational inequality model and discuss the existence of the optimal solution. After that, we prove that provisioning virtual clusters for a multi-tenant data center network that maximizes revenue is NP-hard. Due to the complexity of this problem, an efficient heuristic algorithm OMS (Online Multi-tenancy Scheduling) is proposed to solve the online multi-tenancy scheduling problem. We further explore the virtual cluster placement problem based on the OMS and propose a novel algorithm during the virtual machine placement. We evaluate our algorithms through a series of simulations, and the simulations results demonstrate that OMS can significantly increase the efficiency and total revenue for the data centers.

• 인터넷정보학회논문지
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• 제25권4호
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• pp.39-46
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• 2024

API 게이트웨이는 클라우드 외부의 API 클라이언트가 클라우드 내부 서비스와 통신할 수 있는 단일 진입점을 제공하는 고가용성 구성요소로서 병목 현상을 발생시킬 위험이 크고 서비스 변경 시 재배포가 필요하다. 여러 API 게이트웨이가 구현되고 있는 Java 언어는 배포와 운영 성능의 문제를 극복하기 위해 GraalVM Native Image와 Virtual Thread라는 기술을 발표하였다. Java 애플리케이션에 이들 기술을 적용하기 위해서는 소스 코드 및 배포 절차를 변경해야 한다. 본 연구에서는 API 게이트웨이가 GraalVM Native Image와 Java Virtual Machine(JVM) 기반으로 동작했을 때와 Virtual Thread와 Reactive 스레드 처리 방식 간의 성능을 측정하고 분석하였다. 본 연구에서는 배포 성능과 운영 성능의 평가를 위해 평가지표를 선정하였고 네 가지 환경에서 평가지표의 성능을 측정하고 평가하였다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2011년도 추계학술대회 논문집
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• pp.398-400
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• 2011

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 추계학술대회 논문집
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• pp.106-109
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• 2000

The virtual reality - haptic device is developed for the purpose used in the work that human cannot approach and that need elaborate exercises. To render haptic, the total system is constituted master, haptic device, and slave, remote manipulator. Human operates the remote manipulator. Human operates the remote manipulator relying on the hapti devices and stereo graphic. And then the force and scene of the remote manipulator is fed-back from each haptic devices and virtual devices. The feedback information gets system gain exactly. The system gain provides the most exact haptic and virtual devices. The feedback information gets system gain exactly. The system gain provides the most exact haptic and scene to human by the location, the graphic rendering and the haptic rendering algorithm on real-time. In this research, 3D haptic device is developed for common usage and make human feel the haptic when human contacts virtual object rendered by computer graphic. The haptic device is good for tracing location and producing devices because of the row structure. Also, openGL and Visual Basic is utilized to the algorithms for haptic rendering. The haptic device of this research makes the interface possible not only with virtual reality but also with the real remote manipulator.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.1166-1172
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• 2003

The extremely strong competition among the world automobile industries has introduced the concept of PLM in the total production activities, one of whose major components is VM(Virtual Manufacturing). If the production lines are equipped with robots, the application of OLP in the virtual space is fully mature. However, in the point of the investment's and the maintenance's view, there are always some activities, which can not be automated: for example, typically the manual welding for prefixing in the automobile body shop and the material loading. Process planning for these activities, therefore, are decided mainly by experiences, which caused many repeated rework of the processes and the inconvenience of the workers, and resulted consequently in the reduction of the productivity and the safety of the workers. In this paper, the optimal dimension of the welding gun and its handle position and the optimal working path is simulated and decided by use of DELIMN/IGRIP and DELMIA/Ergo and the working area modelized in the virtual workcell of DELMIA.

• 한국실내디자인학회논문집
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• 제33호
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• pp.3-10
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• 2002

Virtual reality is not a new concept but just a new word and also it isnt limited to the reality created by computer-assisted image composition. Furthermore, we have lived within the virtual reality since long time ago, and the newly emerging digital technology has made the limits of the virtual expression vague and the definition of space concept new, The magical experiences we have had within the digital space consisted of Virtual space are the philosophical subject which we can hardly explain as a simple dichotomous definition such as Virtuality or Reality. But its true that our experiences made within virtual space are felt as much newer space considering those of space design, which have been traditionally made in our physical territory. Digital game is the representative space that provides a new space. Therefore, the new concept in space will be not just the territory expansion of space but also the opportunity we can find a new possibility through the relation between human and space. At this point in time that the life territory is expanding as a new space, this research goal is to show the new possibility of the connection of human and digital space through studying the relationship of Human and Space, Space and Digital space and Human and Digital space as well as The peculiarity of the space which is expressed at Digital game, the most representative space providing new experiences.

• 한국자동차공학회논문집
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• 제18권4호
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• pp.92-98
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• 2010

Virtual ground modeling is one of key topic for real-time vehicle dynamic simulation. This paper discusses about the virtual 3D road modeling process using parametric surface concept. General road data is a type of lumped position vector so interpolation process is required to compute contact of internal surface. The parametric surface has continuity and linearity within boundaries and functions are very simple to find out contact point. In this paper, the parametric surface formula is adopted to road modeling to calculate road hight. Position indexing method is proposed to reduce memory size and resource possession, and a simple mathematical method for contact patch searching is also proposed. The developed road process program is tested in dynamic driving simulation on off-road. Conclusively, the new virtual road program shows high performance of road hight computation in vast field of off-road simulation.