• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.8-8
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• 2000

PICARD (Port-Interface Component Architecture for Real-time system Design) is a software architecture and environment, which is aimed to reduce development time and cost of real-time, control system. With PICARD, a control engineer can construct a control system software by assembling pre-built software components us ing interact ive graphical development environment. PICARD consists of PVM(Picard Virtual Machine) , a component library, and PICE(PIcard Configuration Editor). PVM is a real-time engine of the PICARD system which runs control tasks on a real-time operating system. The component library is composed of components which are called task blocks. PICE is a visual editor which can configure control tasks by creating data-flow diagrams of task blocks or Ladder diagrams for sequential logics. For the communication between PVM on a target system and PICE on a host computer, a simple protocol and tools for stub generation was dove]oped because RPC or CORBA is difficult to be applied for the embedded system. New features such as a byte-code based run time system and a simple and easy MMI builder are also introduced.

• The Journal of Korea Robotics Society
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• v.12 no.1
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• pp.42-54
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• 2017

Using an inverse of the geometric Jacobian matrix is one of the most popular ways to control robot manipulators, because the Jacobian matrix contains the relationship between joint space velocities and operational space velocities. However, the control algorithm based on Jacobian matrix has algorithmic singularities: The robot manipulator becomes unstable when the Jacobian matrix loses rank. To solve this problem, various methods such as damped and filtered inverse have been proposed, but comparative studies to evaluate the performance of these algorithms are insufficient. Thus, this paper deals with a comparative analysis of six representative singularity avoidance algorithms: Damped Pseudo Inverse, Error Damped Pseudo Inverse, Scaled Jacobian Transpose, Selectively Damped Inverse, Filtered Inverse, and Task Transition Method. Especially, these algorithms are verified through computer simulations with a virtual model of a humanoid robot, THORMANG, in order to evaluate tracking error, computational time, and multiple task performance. With the experimental results, this paper contains a deep discussion about the effectiveness and limitations of each algorithm.

• Knowledge Management Research
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• v.23 no.2
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• pp.83-98
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• 2022

The current study investigated the effect of user interface design on metaverse user's objective task performance, perceived usefulness, presence, and enjoyment. Using a 2 × 2 within-subject repeated measure experimental design, we found that users perceived the interface to be significantly more useful when additional visual cues existed and performed better for the given task. Additionally, a repeated-measure mediation analysis revealed that the effect of richer information in the interface on users' enjoyment as a function of need satisfaction was mediated by perceived usefulness. Theoretical and practical implication are derived from the result of the current study.

• Journal of the HCI Society of Korea
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• v.2 no.2
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• pp.45-51
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• 2007

Space planning is one of the popular applications of VR technology including interior design, architecture design, and factory layout. In order to provide easier methods to accommodate physical objects into virtual space planning task, we suggest applying mixed reality (MR) interface. We describe our hardware and software of our MR system designed according to requirements of the application domain. In brief, our system hardware consists of a video see-through display with a touch screen interface, mounted on a mobile platform, and we use screen space 3D manipulations to arrange virtual objects within the MR scene. Investigating the interface with our prototype implementation, we are convinced that our system will help users to design spaces in more easy and effective way.

• KIPS Transactions on Computer and Communication Systems
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• v.4 no.9
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• pp.315-320
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• 2015

In cloud computing, server virtualization supports one or more virtual machines loaded on multiple operating systems on a single physical host server. Migration of a VM is moving the VM running on a source host to another physical machine called target host. A VM live migration is essential to support task performance optimization, energy efficiency and energy saving, fault tolerance and load balancing. In this paper, we propose open source based adaptive VM live migration technique. For this, we design VM monitoring module to decide VM live migration and open source based full-virtualization hypervisor.

• Korean Journal of Computational Design and Engineering
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• v.18 no.4
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• pp.290-298
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• 2013

A walking navigation system (usually known as a locomotion interface) is an interactive platform which gives simulated walking sensation to users using sensed bipedal motion signals. This enables us to perform navigation tasks using only bipedal movement. Especially, it is useful for the certain VR task which emphasizes on physical human movement, or accompanies understanding of the size and complexity of building structures. In this work, we described system components of VR walking system and investigated several types of walking platform by literature survey. We adopted a MS Kinect depth sensor for the motion recognition and a treadmill which includes directional turning mechanism for the walking platform. Through the integration of these components with a VR navigation scenario, we developed a simple VR walking navigation system. Finally several technical issues were found during development process, and further research directions were suggested for the system improvement.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.8
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• pp.3865-3883
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• 2016

Infrastructure as a Service (IaaS) encapsulates computer hardware into a large amount of virtual and manageable instances mainly in the form of virtual machine (VM), and provides rental service for users. Currently, VM anomaly incidents occasionally occur, which leads to performance issues and even downtime. This paper aims at detecting anomalous VMs based on performance metrics data of VMs. Due to the dynamic nature and increasing scale of IaaS, detecting anomalous VMs from voluminous correlated and non-Gaussian monitored performance data is a challenging task. This paper designs an anomaly detection framework to solve this challenge. First, it collects 53 performance metrics to reflect the running state of each VM. The collected performance metrics are testified not to follow the Gaussian distribution. Then, it employs independent components analysis (ICA) instead of principal component analysis (PCA) to extract independent components from collected non-Gaussian performance metric data. For anomaly detection, it employs multi-class Bayesian classification to determine the current state of each VM. To evaluate the performance of the designed detection framework, four types of anomalies are separately or jointly injected into randomly selected VMs in a campus-wide testbed. The experimental results show that ICA-based detection mechanism outperforms PCA-based and LDA-based detection mechanisms in terms of sensitivity and specificity.

• 한국HCI학회:학술대회논문집
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• 2009.02a
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• pp.1239-1245
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• 2009

가상현실의 자연스러운 응용분야는 작업 훈련(Task Training) 분야이다. 이러한 작업 훈련 분야에서 가장 중요한 요소 중 하나는 각성 수준(Arousal Level)으로, 적절한 각성 수준은 과제 훈련의 효과를 결정짓는다. 본 연구는 VR 환경과 Desktop 환경의 자동차 운전 시뮬레이터에서 피험자가 실험을 위하여 설계된 2 개의 시나리오를 수행하는 동안 피험자의 생리 신호를 측정하고, 실험 후 각 환경에 대한 주관적인 실재감을 측정하여, 두 실험 환경 사이에 피험자의 주관적인 실재감이 유의한 차이가 있는지 알아보고, 피험자가 수행한 시나리오와 시나리오에 종속된 실험 태스크에 대하여, 각성 수준을 평가할 때 유용한 지표로 활용되는 피부전도도(GSR) 반응이 피험자의 주관적인 실재감의 결과와 어떠한 관계를 보이는지 살펴 보았다. 실험 결과 두 실험 환경 사이의 피험자의 주관적인 실재감은 유의한 차이가 있었고, VR 환경에서 더 높게 나왔다. 그러나 두 실험 환경 사이의 피험자의 생리적 각성 반응은 실재감의 결과처럼 유의한 차이를 보여주지 못했으며, 오히려 시나리오에 종속된 실험 태스크에 따라서 유의한 차이를 보여주었다. 따라서 실재감과 피부전도도 (GSR)측정에 의한 각성도 는 직접적인 관계가 적은 것으로 생각되며, 이는 피부전도도(GSR)를 실재감의 한 척도로 쓰기에는 적합하지 않을 수 있다는 것을 의미한다.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2004.02a
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• pp.205-219
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• 2004

The remote operation of the Advanced Spent Fuel Conditioning Process (ACP) is analyzed by using the 3D graphic simulation tools. The ACP equipment operates in intense radiation fields as well as in a high temperature. Thus, the equipment should be designed in consideration of the remote handling and maintenance. As well as suitable remote handling and maintenance technology needs to be developed along with the design of the process concepts. To develop such remote operation technology, we developed the graphic simulator which provides the capability of verifying the remote operability of the ACP without fabrication of the process equipment. In other words, by applying virtual reality to the remote maintenance operation, a remote operation task can be simulated in the graphic simulator, not in the real environment. The graphic simulator will substantially reduce the cost of the development of the remote handling and maintenance procedure as well as the process equipment, while at the same time developing a remote maintenance concept that is more reliable, easier to implement, and easier to understand.

• The Journal of Society for e-Business Studies
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• v.2 no.1
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• pp.21-37
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• 1997

As the complexity in design and manufacturing activities of distributed virtual enterprises rapidly increases, the issue of process management becomes more critical to shorten the time-to-market, reduce the manufacturing cost and improve the product quality. This paper proposes a unified framework to manage design and manufacturing processes in a distributed environment. We present a methodology which utilizes process flow graphs to depict the hierarchical structure of workflows and process grammars to represent various design processes and design tools. To implement the proposed concept, we develop a process management system which mainly consists of a cockpit and manager programs, and we finally address a preliminary implementation procedure based on the Object Modeling Technique. Since the proposed framework can be a formal approach to the process management by providing formalism, parallelism, reusability, and flexibility, it can be effectively applied to further application domains of distributed virtual enterprises.