• The Journal of the Korean dental association
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• v.57 no.3
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• pp.175-184
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• 2019

Increasing the aesthetic needs of patients and decreasing the use of amalgam had led to increased demand for dental resin composite. Thereby, light curing unit (LCU) has become an essential equipment in dental clinic. To ensure long-term prognosis of photopolymerized materials, LCU should have a uniform and consistent radiant output and an emission spectrum that includes the active wavelength range of photoinitiators. In addition, when the correct use and thorough maintenance and repair of LCU are performed, the higher success rate of restoration using photopolymerization materials will be achieved.

• Bulletin of the Korean Chemical Society
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• v.26 no.5
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• pp.715-716
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• 2005

• Journal of the Korean Institute of Telematics and Electronics S
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• v.34S no.12
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• pp.106-113
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• 1997

While driving, the low frequency interior noise below 200Hz causes the main component that irritates the auditory acoustic sense. But these passive control methods bring out increment in cost and weight of the vehicle and result in low efficiency. Recently, various ANC(Active Noise Control) methos to suppress the low frequency noise began to launch into application. In this study, we implemented the active noise control system for passenger vehicle to cancel the engine booming noise using DSP-based control unit, 4 micorphones, and 2 speakers. We used MEFX-LMS (Multiple Error Filtered X-Least Mean Square) algorithm since it can be easily implemented in real time. Also, MEFX-RLS algorithm was taken to enhance the suppression of the harmonic components of the engine booming noise inspite of its computational complexity. The performance of two adaptive algorithms were analyzed with experimental resutls.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.969-974
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• 2008

As the railway becomes higher, the reliable stability and riding comfort of higher railway are required. To improve the riding comfort of high-speed trains, it is very helpful to use active suspension system for railway. In Japan, the high-speed train, Shinkansen has adopted semi-active suspension system and now it is running in the main trunk. In this paper, the authors introduce several technical trends of vibration control methods of Japanese Shinkansen. And the installation of semi-active suspension to HSR 350x and the test result of test run on the Kyoung-Bu high speed ling are also explained. After development of HSR 350x, new R&D national project of high speed train is progressed by Ministry of Land, Transport, and Maritime Affairs. This project is the development of Electric Multiple Unit of high speed train with 400km/h of maximum test speed. These result would be helpful to progress next generation high speed project.

• Journal of Korean Institute of Industrial Engineers
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• v.26 no.3
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• pp.227-237
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• 2000

A workflow management system is a software system to assist designing processes, controlling and managing the execution of the designed processes. One emerging trend in many recent information systems is the provision of process management functions. In this paper, we propose a method of designing processes for automatic process execution directly from process modeling. First of all, the concept of block is presented which is to define a nested process model. A block is the minimum unit that can specify the relationships of process components, i.e., tasks. A general process can be defined by a combination of the blocks defined in this paper. An algorithm is developed to transform a general flat process model into a nested model. We identify basic types of blocks and build ECA (Event-Condition-Action) rules for each of the basic types. This allows us to automate the execution of the process model by using the active features of active databases.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.33 no.5
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• pp.25-29
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• 2001

Dimethyldioxirane (DMD), which is a source of active oxygen, is effective agent that can be used in chemical pulp bleaching. In this study, delignification of kraft bagasse pulp has been carried out by using DMD. The effect of the applied charge of DMD (as active oxygen) and pH of the delignification medium were studied. The optimum conditions of the applied DMD charge and pH of the delignification reaction were achieved at pH range from 8~9, 2% of DMD (as active oxygen) and the rest of delignification reaction conditions were $25^{\circ}C$, 60 min, and 12% pulp consistency. The development of brightness per unit kappa number removal (ΔBrightness/ Δ Kappa number) has highest value at the optimum condition. The study showed that the reactivity of kraft bagasse pulp be enhanced to wards alkaline hydrogen peroxide bleaching by pulp treatment with DMD.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.46 no.4
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• pp.17-22
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• 2009

FlexRay is a new standard of network communication system which provides solutions to the degradation problems generated by many ECU (Electronic Control Unit) connections in automobiles and automation systems. The upper bound of the data rate is 10Mbps and it provides two channels for redundancy In this paper, FlexRay system is first designed using SDL. For hardware implementation, FlexRay system is designed using Verilog HDL based on the SDL design result. The designed system is synthesized using Synopsys Design Compiler with the Magna/Hynix 0.18 um cell library. In this paper, to construct a FlexRay network, active star is used since active star systems can provide high speed data transmission up to 10Mbps. The performance of the star network is tested using one transmitter node and two receiver nodes.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.1-4
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• 2008

Fuel cells have the potential of providing several times higher energy storage densities than those possible using current state-of-the-art lithium-ion batteries, but current energy density of fuel cell system is not better than that of lithium-ion batteries. To achieve the high energy density, volume and weight of fuel cell system need to be reduced by miniaturizing system components such as stack, fuel tank, and balance-of-plant. In this paper, the thin flexible PCB (Printed circuit board) is used as a current collector to reduce the stack volume. Two end plates are made from light weight aluminum alloy plate. The plate surface is wholly oxidized through the anodizing treatment for electrical insulation. The opening rate of cathode plate hole is optimized through unit cell performance measurement of various opening rates. The performances are measured at room temperature and ambient pressure condition without any repulsive air supply. The active area of MEA is 10.08 $cm^2$ and active area per a unit cell is 1.68 $cm^2$. The peak power density is about 210 mW/$cm^2$ and the air-breathing planar stack of 2 Wis achieved as a small volume of 18 cc.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.16 no.5
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• pp.112-118
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• 2002

The adaptive m filters is more effective than m filters when acoustic feedback exists, in which cause an order of a FIR filter must be very large if some of poles of the ideal control filter are near the unit circle. But the IIR filters may have stability problems especially when the adaptive algorithm is not converged. In this paper, a stabilizing procedure for adaptive IIR filters is proposed. In the beginning of the ANC system, it improve a stability by pulling the poles of the IIR filter to the center of the unit circle, and it returns the poles to their original positions after the filter converge. Computer simulations and experiments are performed to show the effectiveness of proposed schemes.

• Knowledge Management Research
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• v.19 no.2
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• pp.1-19
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• 2018

This study aims to identify the causal relationship among public technology transfer, technological performance, and research and development (R&D) productivity. Using the impulse-response function(IRF) of a panel vector autoregressive model (panel VAR), this study suggests the results of how long the factors such as technological performance (patent), public technology transfer, and R&D productivity takes and lasts if a one-unit shock of standard deviation occurs. As a result, first, the increase of public technology transfer activities has no power to increase the technology performance but improve the R&D productivity. If the public institute increases its technology transfer activities by one unit, the R&D productivity will increase within five years. Second, the impact of increasing technological performance on improvement of public technology transfer and R&D productivity is an insignificant. Third, the effect of R&D productivity on the public technology transfer creates a substantial reaction after a current time. Considering the structural relationships among public technology transfer, technological performance, and R&D productivity, if policy makers intend to construct the active R&D circumstance, technology suppliers should be motivated to run the active R&D mechanism because they achieve gains.