• Journal of Institute of Control, Robotics and Systems
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• v.8 no.5
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• pp.413-417
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• 2002

The Internet technology has been recognized not only as a tool far communication in the 21st century but also as an environment for enabling changes in the paradigm of teaching and learning. This paper describes a web-based system development for chemical engineering education. Simulation and visualization of dynamic systems in the environment of a standard web-browser is made possible by extending its capabilities. ActiveX control is used to simulate the system tool far online representation of Virtual Lab. System that is developed using visual basic. The courseware is classified into tutorial, exercises, and virtual experiments.

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.4
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• pp.389-394
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• 2014

This paper presents the effect of a reflective force computed from a first-order-hold method on the stability of a haptic system. A haptic system is composed of a haptic device with a mass and a damper, a virtual spring, a sampler and a sample-and-hold. The boundary condition of the maximum virtual stiffness is analytically derived by using the Routh-Hurwitz criterion and the condition shows that the maximum virtual stiffness is proportional to the square root of the mass and the damper of a haptic device and also is inversely proportional to the sampling time to the power of three over two. The effectiveness of the derived condition is evaluated by the simulation. When the reflective forces are computed by using the first-order-hold method, the maximum available stiffness to guarantee the stability is increased several hundred times as large as when the zero-order-hold method is applied.

• Journal of the Korea Society of Computer and Information
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• v.22 no.5
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• pp.11-19
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• 2017

In this paper, we propose a hypervisor for embedded systems based on ARM microprocessor. The proposed hypervisor makes it possible to run several real-time kernels concurrently on a single embedded system by virtualizing its microprocessor. With assistance of MMU, it supports virtual memory which enables each guest operating system has its own address space. Exploiting the fact that most embedded systems use memory-mapped I/O device, it provides a mechanism to distribute an external interrupt to virtual machines properly. It also achieves load balancing through live migration which moves a running virtual machine to other embedded system. Unlike other para-virtualization techniques, minor modifications are needed to run it on the hypervisor. Extensive performance measurement studies are conducted to show that the proposed hypervisor has enough potentiality of its real-world application.

• Speech Sciences
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• v.9 no.2
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• pp.135-146
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• 2002

Generally a speaker verification system improves its system recognition ratio by regularizing log likelihood ratio, using a speaker model and its background speaker model that are required to be verified. The speaker-based cohort method is one of the methods that are widely used for selecting background speaker model. Recently, Gaussian-based cohort model has been suggested as a virtually synthesized cohort model, and unlike a speaker-based model, this is the method that chooses only the probability distributions close to basic speaker's probability distribution among the several neighboring speakers' probability distributions and thereby synthesizes a new virtual speaker model. It shows more excellent results than the existing speaker-based method. This study compared the existing speaker-based background speaker models and virtual speaker models and then constructed new virtual background speaker model groups which combined them in a certain ratio. For this, this study constructed a speaker verification system that uses GMM (Gaussin Mixture Model), and found that the suggested method of selecting virtual background speaker model shows more improved performance.

• IE interfaces
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• v.14 no.1
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• pp.1-8
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• 2001

This paper presented a web-based virtual system to simulate forging operation. The system utilized simulation techniques of Finite Element Method (FEM) to analyze the forging process and Virtual Reality Modeling Language (VRML) to visualize the simulation results in the web. The analysis using FEM could show mechanical information such as stresses and deformation profiles of a specimen during forging process and the analysis results were transferred into virtual space using VRML. Since the forging machine and specimen were modeled using Java and VRML, the forging machine and analysis results were browsed and integrated on the web that is interfaced to users through EAI to show the whole forging simulation. The developed system realized the working environment virtually so that education and experiment could be performed effectively even on the PC.

• Proceedings of the KOSOMBE Conference
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• v.1996 no.11
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• pp.107-110
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• 1996

We proposed a new system for the postural balance rehabilitation training. For the purpose, we used the virtual hiking system using virtual reality technology. We evaluated the system by measuring the parameters such as path deviation, path deviation velocity, cycling time, and head movement. From our results, we verified the usefulness of virtual reality technology in rehabilitation. Our results showed that this system was effective postural balance rehabilitation training device and might be useful as the clinical equipment.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.4
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• pp.173-179
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• 2003

In this paper, a real-time multibody vehicle dynamics and control model has been developed for a virtual reality intelligent vehicle simulator. The simulator consists of low PCs for a virtual reality visualization system, vehicle dynamics and control analysis system a control loading system, and a network monitoring system. Virtual environment is created by 3D Studio Max graphic tool and OpenGVS real-time rendering library. A real-time vehicle dynamics and control model consists of a control module based on the sliding mode control for adaptive cruise control and a real-time multibody vehicle dynamics module based on the subsystem synthesis method. To verify the real-time capability of the model, cut-in, cut-out simulations have been carried out.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2000.08a
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• pp.145-148
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• 2000

Nowadays there are lots of researches on robot systems working on danger environments and control led remotely. In this paper, we describe a virtual robot interface system based on Internet In the system, a client can order scanning for range finding, then server detects a 3D profile data from the objects by using robot controlling and a range finder automatically. If one clicks the original position of object and destination on virtual space, the robot moves the object to the new position in real space. The proposed interface system supports advanced virtual 3D interface and makes it possible one to manage the objects remotely more conveniently.

• Journal of KIISE:Computing Practices and Letters
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• v.15 no.12
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• pp.1003-1007
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• 2009

Client-side attacks including drive-by download target vulnerabilities in client applications that interact with a malicious server or process malicious data. A typical client-side attack is web-based one related to a malicious web page exploiting specific browser vulnerability that can execute mal ware on the client system (PC) or give complete control of it to the malicious server. To defend those attacks, this paper has constructed high interaction client honeypot system using Capture-HPC that adopts execution-based detection in virtual machine. We have detected and classified malicious web pages using the system. We have also analyzed the system's performance in terms of the number of virtual machine images and the number of browsers executed simultaneously in each virtual machine. Experimental results show that the system with one virtual machine image obtains better performance with less reverting overhead. The system also shows good performance when the number of browsers executed simultaneously in a virtual machine is 50.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.39 no.3
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• pp.62-78
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• 2002

In this paper, we describe a system that can interact with agents in the virtual space incorporated in the system. This system is constructed by an analysis system for analyzing human gesture and an interact system for interacting with agents in the virtual space using analyzed information. An implemented analysis system for analyzing gesture extracts a head and hands region after taking image sequence of an operator's continuous behavior using CCD cameras. In interact system, we construct the virtual space that exist an avatar which incarnating operator himself, an autonomous object (like a Puppy), and non-autonomous objects which are table, door, window and object. Recognized gesture is transmitted to the avatar in the virtual space, then transit to next state based on state transition diagram. State transition diagram is represented in a graph in which each state represented as node and connect with link. In the virtual space, the agent link an avatar can open and close a window and a door, grab or move an object like a ball, order a puppy to do and respond to the Puppy's behavior as does the puppy.