• Journal of Institute of Control, Robotics and Systems
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• v.9 no.1
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• pp.90-98
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• 2003

The real-time industrial network, often referred to as fieldbus, is an important element for building automated manufacturing systems. Thus, in order to satisfy the real-time requirements of field devices, numerous fieldbus protocols have been announced. But the application of fieldbus has been limited due to the high cost of hardware and the difficulty in interfacing with multi-vendor products. Therefore, as an alternative to fieldbus, the computer network technology, especially Ethernet (IEEE 802.3), is being adapted to the industrial environment. However, the crucial technical obstacle for Ethernet is its non-deterministic behavior that makes it inadequate for industrial applications where real-time data have to be delivered within a certain time limit. Recently, the development of switched Ethernet shows a very promising prospect for industrial application due to the elimination of uncertainties in the network operation resulting in much improved performance. This paper focuses on the application of the switched Ethernet for industrial communications. More specifically, this paper presents an analytical and experimental performance evaluation of the switched Ethernet and a case study about networked control system.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.32 no.4
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• pp.169-177
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• 2009

Concurrent Engineering (CE) has presented new possibilities for successful product development by incorporating various product life-cycle functions from the earlier stage of design. In the product design, geometric representation is vital not only in its traditional role as a means of communicating design information but also in its role as a means of externalizing designer's thought process by visualizing the design product. During the last dozens of years, there has been extraordinary development of computer-aided tools intended to generate, present or communicate 3D models. However, there has not been comparable progress in the development of 3D-CAD systems intended to represent and manipulate a variety of product life-cycle information in a consistent manner. In the previous research, the authors proposed a novel concept called Minus Volume (MV) to incorporate various design information relevant to product life-cycle functions. This paper proposes the use of the MV concept for the collaborative design environment, where many team members are geographically distributed over the networked environment, including Internet, Intranet, WWW, etc. A prototype 3D-CAD system is implemented based on the MV concept and illustrated with the successful implementation of collaborative design example.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.765-766
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• 2010

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.51 no.4
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• pp.206-210
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• 2002

The transmission delays in the networked control systems affect the performance and stability. For covering the delays, this paper proposes NCS including the predictive strategy. The proposed method shows that the two cases such as stable and unstable system are well behaved.

• Journal of Korea Multimedia Society
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• v.4 no.2
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• pp.130-135
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• 2001

When a networked virtual reality system handles composite media audio and video as well as three dimensional computer graphics, the quality of the virtual space is greatly affected by the current available network, and end system resources. Even if the network can preserve a certain amount of resources, the required resources change dynamically according to the user\`s navigation of a large virtual space, and then it may decrease the quality of the virtual space. In this paper, a method for resource allocation is proposed and the proposed system copes with the deterioration of quality of virtual spaces in case that the starvation of system resources occurs. The experimental results show that the proposed method is efficient.

• Korean Journal of Computational Design and Engineering
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• v.9 no.3
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• pp.212-219
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• 2004

This paper presents the visualization method of the KAIST interactive bicycle simulator. The simulator consists of two bicycles of 6 DOF and 4 DOF platforms, force feedback handlebars and pedal resistance systems to generate motion feelings; a real-time visual simulator, a HMD and a beam projection system; and a 3D sound system. The system has an integrating control network with the server-client network structure for multiple simulators. The visual simulator generates dynamic images in real-time while communicating with other modules of the simulator. The operator of the simulator can have realistic visual experience of riding on a velodrome or through the KAIST campus, while being able to watch the other bicycle with an avatar.

• IEMEK Journal of Embedded Systems and Applications
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• v.2 no.1
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• pp.1-8
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• 2007

In this paper, we developed a file system architecture for portable multimedia devices. To enhance user convenience, the information about the stored files should be easily retrieved and organized. We defined NMD (Networked MetaData), which can organize the files in networked fashion by attaching user-defined attributes and relation between files. The NMD is stored in flash memory to utilize its nonvolatile property and low-power consumption, while multimedia files are stored in hard disk, an inexpensive mass storage. The experimental implementation showed that this architecture was able to save about 10% power compared to the hard disk NMD-store.

• IEMEK Journal of Embedded Systems and Applications
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• v.3 no.3
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• pp.136-142
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• 2008

Mobile robots can offer services like intelligent monitoring in an indoor environment using network connection with remote users. In this paper, we designed and developed a networked security robot system with various sensors, such as flame detector, gas detector, sound monitoring module, and temperature sensor, etc. The robot can be accessed through a web service and the user can check the status of the environment. Using ADAMS software, we defined the motor specification for a worst-case condition of climbing over a obstacle. We applied the robot system in monitoring office condition.

• Journal of the Korean Society for information Management
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• v.15 no.1
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• pp.19-42
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• 1998

Most of the work done in developing Z39.50 was carried out in the basic protocol framework. It becomes apparent that some problems would be quite unacceptable in implementing and reinforcing the networked information retrieval and that it needs some other arrangement such as ISP. This article discussed the current modifications like ISPs by reviewing the unique characters of Z39.50 and the overall design of a client-server search systems, and also distinguished the Z39.50 clients that have been developed as non-profits from those of profits in the perspective of Z39.50 function-expanding.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.3 no.3
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• pp.51-61
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• 2010

Nowadays, there are various networked systems with many computers. In most networked systems, a crucial objective is to keep transmitting and/or receiving data continuously even though failures exist. How can one make a computer continue transmitting and/or receiving data even when there are some errors on a link? Fault-Tolerant Ethernet (FTE) can be a solution to this question. In this paper, we propose a Localized Software-based Fault-Tolerant Ethernet (LSFTE). Our new approach fulfills the general FTE requirements. It takes advantage of redundant cable lines to maintain communication in a faulty environment. A software layer, which uses a simple and effective algorithm, is added above the LAN card driver software to detect and overcome faults. For our approach, there is no need to change the existing hardware or the end-use interfaces. Furthermore, the fault-detection time is reduced significantly compared to the conventional software-based approach.