• Journal of Korea Multimedia Society
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• v.23 no.1
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• pp.58-66
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• 2020

5G-based HMD technology grew rapidly in the context of the environment change of convergence technology media and mobile networks in the fourth industrial era. It has also grown into a core technology that transforms our digital visual system. However, there is no research or system that can understand and verify radical visual system changes. Therefore, it is necessary to have an engineering understanding and verification of the diffusion of HMD media imaging devices. Beyond the distinction between virtual and real, research is urgently needed on the new three-dimensional interface of the 21st century through viewer participation. For this reason, research on the algorithm structure of interactive video media using L-System is an essential process and will be a guide to understanding the virtual reality interactive environment.

• Journal of the Optical Society of Korea
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• v.10 no.2
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• pp.76-80
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• 2006

The proposed technique uses a combination of two systems, viz. a three dimensional stereoscopic system and a two-lens system. This novel combined system successfully produces a stereoscopic floating image in mid air near the observer. The two-lens system produces a floating image from the stereoscopic image originating from the stereoscopic system, and the two lenses eliminate the defects of the floating lens and concave mirror. The experimental results show that the two lenses eliminate the defects of the lens and the concave mirror, so that the proposed system successfully produces a touchable stereoscopic floating image.

• Proceedings of the KIEE Conference
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• 2001.10a
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• pp.289-292
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• 2001

A Dual rotor turbines HAWT/VAWT combined wind turbine system that can drastically enhance the power production capability compared to conventional Single Rotor Turbine HAWT system. The combined system that takes advantage of strong point of both horizontal and vertical Axis wind turbine system developed by a venture firm : KOWINTEC of Chonbuk National University. The HAWT/VAWT hybrid system has been successfully field tested and commercial operation since Feb. 12, 2001 in Hae-chang rest park, Bu-an county near the Sae Man-Kum Sea Dike. This paper will briefly describe the field test results performance and a special aerodynamic structure with bevel-planetary gear box of Dual Rotor Wind Turbine system.

• The Transactions of the Korean Institute of Power Electronics
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• v.26 no.5
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• pp.307-314
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• 2021

Even though the LCL filters have superior harmonic attenuation ability to L filters, stability has always been an issue. The system could be unstable because of the resonance phenomenon, especially when digital controller is used. Adding a notch filter to the compensator is one approach to solve the problem. Resonance phenomenon can be inhibited by aligning notch frequency to system resonance frequency. However, resonance frequency variation can be obtained because the actual system has a nonstationary characteristic. Therefore, the system could be unstable, where the system parameters are changed when the conventional notch filter is used. An adaptive digital notch filter that stabilizes the system even system parameters are changed. Simulation and experiment results are provided to verify the validity of the proposed adaptive filter.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.2147-2150
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• 2003

Recently, many technologies of the P.L.C (Power Line Carrier) are introduced for an efficient communication. P.L.C communication sends information in the carrier signals by conduction over the power wire. An arc detector is proposed in this paper for the effective transmission. The Power Line Carrier has an advantage in low cost because it uses existent power line. It can be easily applied anywhere that a power line socket is available. But the P.L.C. is very noisy, because many electronic devices in generate electronic noise in modulated signals. This problem should be considered carefully in the design of the arc detector system using P.L.C in railway. The proposed system can be applied for monitoring the arc detector system and the arc locator system in railway. Hence the system will be able to exchange the arc information to be T.C.M.S. (Train Control Management System), bogies and even between a station and trains in railway and use to suspicion fire in train.

• Proceedings of the KOSOMBE Conference
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• v.1997 no.11
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• pp.206-209
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• 1997

The stereostatic surgery becomes a important part of neurosurgery. The conventional style of stereostatic system uses a input method of film digitizing. It is time consuming and laborious. In this paper, we presented a system that can manage digital images from medical imaging machine to surgery assisting program. CT images were transferred in DICOM format to a surgery assisting computer in a operation room through PACS. The streotatic surgery assisting program processed the digital images and calculated the parameters that were required in steostatic surgery. The assisting program were developed that can detect the reference points automatically, transform CT coordinate to frame coordinate and calculate the RM (Riechert-Mundinger) frame. This system were applied to clinical cases in Seoul National Univ. Hospital. The two advantages of this system were revealed. The processing time from imaging to surgery parameters were much aster than conventional system. The surgery accuracy were more mininute as the digitizing error were reduced. This system were a good application of connecting imaging machines to clinical treatment system through PACS.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.13
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• pp.1033-1055
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• 2000

Almost business enterprises have recently used electronic commerce to conduct their business. Electronic commerce has come to encompass the Internet as well as EDI on private networks begun in the 1960s. The Internet is already changing the way that many companies conduct their business. Domestic electronic commerce has rapidly enhanced, while Int'l electronic commerce has gone steady. There are four issues for developing of Int'l Electronic Commerce. Firstly, The EDI Standardization is to be uniformed and prevailed over the world in UN/EDIFACT authorized by ISO. Secondly, There are two useful systems on Electronic Document Transmission, so called, Bolero project system and Trade Card System. It is thought that Bolero system will be more useful for large trading enterprises, especially, who need a Letter of Credit and electronic B/L, while T/C system is proper to small trade companies who do not need those. Successful results of Bolero system is very important for Int'l electronic commerce enterprises. Thirdly, to secure electronic signature, Int'l Certification Authority is essential for the users of Int'l electronic commerce. Trusted way of distributing public keys is to use a Int'l Certification Authority. The Int'l Certification Authority will accept user's public key, along with some proof of identity and serve as a depository of digital certificates. Both governments and the International business community must involve archiving keys with trusted third parties. Finally, It is important that all the nations and UNCITRAL continue efforts to make legal bases in Int'l electronic commerce concerned, including electronic signature, certification etc.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.13 no.6
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• pp.145-159
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• 2010

A Sustainable Structured wetland Biotop (SSB) system was planned, designed, and finally constructed, and maintained in the An-teo Reservoir ecological park, which is the habitat of the endangered Gold-spotted Pond Frog. The system purifies polluted water of An-teo Reservoir which flows from up to bottom within the system. Water was sampled once a month at the inlet and at the outlet from December, 2009 to August, 2010. BOD5, SS, T-N and T-P were analyzed. Average influent and effluent BOD5 concentration was 2.9 and 1.0 mg/L, respectively, and BOD5 removal was 67%. SS concentration of influent and effluent averaged 18.1 mg/L and 2.5 mg/L, respectively, and SS abatement amounted to 86%. Average influent and effluent T-N concentration was 0.426 mg/L and 0.147 mg/L, respectively, and T-N retention was 66%. T-P concentration of influent and effluent averaged 0.071 mg/L and 0.022 mg/L, respectively, and T-P removal amounted to 68%. Plant and frog species of the system were monitored during the period. Amphibia and reptiles provided 7 species and 4 families including the Endangered Gold-Spotted Pond Frog (Rana chosenica ) which also lives in the system. Twenty-six plant species were naturally introduced into the system, however, they didn't make up a significant portion of the plant populations compared with the planted species. The endangered plants, Bladderwort (Utricularia vulgaris var. japonica ) and Euryale ferox were observed in An-teo Reservoir as well as in the system.

• Journal of the Korean Institute of Intelligent Systems
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• v.18 no.6
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• pp.762-767
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• 2008

This paper introduces a $L_{\infty}$-gain state feedback fuzzy controller design for the time delay nonlinear system represented by Takagi-Sugeno(T-S) fuzzy model. First, the T-S fuzzy model is employed to represent the time delay nonlinear system. Next based on the fuzzy model, a fuzzy state feedback controller is developed to achieve $L_{\infty}$-gain performance. Finally, sufficient conditions are derived for $L_{\infty}$-gain performance. The sufficient conditions are formulated in the format of linear matrix inequalities (LMIs). The effectiveness of the proposed controller design methonology is finally demonstrated through numerical simulations.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.9
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• pp.59-70
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• 2007

In this paper, we proposed an effective T&L(Transform & Lighting) Processor architecture for a real time 3D graphics acceleration SoC(System on a Chip) in a mobile system. We designed Floating point arithmetic IPs for a T&L processor. And we verified IPs using a SoC Platform. Designed T&L Processor consists of 24 bit floating point data format and 16 bit fixed point data format, and supports the pipeline keeping the balance between Transform process and Lighting process using a parallel computation of 3D graphics. The delay of pipeline processing only Transform operation is almost same as the delay processing both Transform operation and Lighting operation. Designed T&L Processor is implemented and verified using a SoC Platform. The T&L Processor operates at 80MHz frequency in Xilinx-Virtex4 FPGA. The processing speed is measured at the rate of 20M Vertexes/sec.