• KIEAE Journal
• /
• v.7 no.4
• /
• pp.135-140
• /
• 2007

In this study we settled the trouble of the MgO board of existence by this research. We changed the wooden one of the main ingredient of a board to a perlite and a mineral particle in the aluminum hydroxide group and proceeded with a study to physical character and fire resistance efficiency improvement. The result yellowing phenomenon could be improved and it was possible to reduce size decrease of pin hole and the frequency of occurrence. We found out that the in case of absorbed amount added 5~8% corresponding to the weight decreases the acrylic group emulsion suddenly. So this product is improved with the bending strength and water-resistance. After behavior stop time measurement of a mouse for experiments was measured at the time of a gas harmful effect test, an improved MgO board appeared more highly for an average of 138 seconds compared with a board of existence.

• 제어로봇시스템학회:학술대회논문집
• /
• 1992.10b
• /
• pp.306-311
• /
• 1992

We propose software algorithms which provide the characteristics of acceleration/deceleration essential to high dynamic performance at the transient state where industrial robots or CNC machine tools start and stop. The path error, which is one of the most significant factors in performance evaluation of industrial robots and CNC machine tools, is analyzed for linear, exponential, and parabolic acceleration/deceleration algorithms in case of circular interpolation. The analysis shows that the path error depends on the acceleration/deceleration routine and the servo control system. In experiments, the entire control algorithm including the proposed acceleration/deceleration algorithms is executed on the motion control system with a floating point digital signal processor(DSP) TMS320C30 as a CPU. The experimental results demonstrate that the proposed algorithms are very effective in controlling axes of motion of industrial robots or CNC machine tools with the desired characteristics.

• Journal of the Korea Society of Computer and Information
• /
• v.22 no.1
• /
• pp.99-106
• /
• 2017

In this paper, the first to identify in detail the direct and indirect causes of trade claims and to provide a way to prevent the causes and measures specific claims. Trade claims is not the best way to prevent in advance, measures to prevent future trade claims is as follows. First, it should be the credit investigation of the counterparts. Second, the contract must determine the rights and obligations of each other through sufficient consultation with contract and faithfully perform its contractual obligations. Third, the explicit trade arbitration clause of arbitration in the contract, and shall be a sufficient review of the procedure such as import and export, international business practices, norms and partners of economic policy, foreign exchange regulations, the trade system transactions. Finally, for it is to be treated as a one-stop strengthening the organization and function, and the Ministry of Commerce and Trade Association, and KOTRA and Trade Insurance Corporation strategic support systems, such as done by covering the work on trade claims prevention and resolution in the Korean Commercial Arbitration Board.

• Proceedings of the KSR Conference
• /
• 2003.05a
• /
• pp.68-81
• /
• 2003

Rockfall protection fence is one of the most common rockfall protection methods in Korea. If rockfall protection fences are required along the road or railway, their location, height and capacity, in terms of the maximum kinetic energy that they can absorb, should be specified. Within this paper, the best practice of rockfall barrier is introduced. Modern rockfall simulations as a means to define risks, protection requirements, dynamic loading and height of potential structures and selection of appropriate placement is presented. Technical possibilities of rockfall barriers and their actual limits are presented. Safety concepts based on probabilities approaches are proposed. Recent studies performed in other countries show that Flexible Barriers are also a feasible system to stop and retain debris flows. Finally an outlook onto further development is given.

• Proceedings of the KSR Conference
• /
• 2002.10a
• /
• pp.408-413
• /
• 2002

From the moment that electricity is applied to a relay, a wheel turned, or a valve opened, the process leading to the need for maintenance begins, The uninitiated will tell you that the Maintenance man is someone who repairs something when it has gone wrong. Unfortunately, in any large engineering concern, such as a railway, it is not possible to work on the principle that only when something breaks down should it get any attention. The failure of one contact, diode or bearing could well stop not only the assembly of which it is a part, but the flow line or process, with loss of revenue, and clientele, and often with effects on the safety of both staff and the traveling public. So, we have to establish the reliable and cost-effective maintenance system to resolve these problems.

• Journal of Electrical Engineering and Technology
• /
• v.9 no.3
• /
• pp.1132-1136
• /
• 2014

In the context of increasing electric energy consumption in a data center, energy efficiency improvement is strongly emphasized. In a data center, electric energy is largely consumed by DC power supply system, which is based on a rectifier composed by multiple parallel converters. Therefore, rectifier efficiency must be improved for minimizing loss of DC power supply system. Rectifier efficiency can be modulated by load allocation to converters because converter efficiency depends on input AC power. In this paper, we propose a new control method to maximize rectifier efficiency. The method can control load allocation to converters by introducing active power converter control scheme and start-and-stop of converters. In order to illustrate optimal load allocations in a rectifier, a maximization problem of rectifier efficiency is formulated as a nonlinear optimization one. The problem is solved by Lagrangian relaxation method and the computation results provide the validity of proposed method.

• Proceedings of the KSR Conference
• /
• 2008.11b
• /
• pp.1807-1820
• /
• 2008

The station area development planed to improve the old and narrowed station and to enhance the train passenger's convenience through private capital attraction in the past. But it has been faced with difficulty for the creative of transfer demand. Because of lean upon building facilities were caused by shortage of business profitability as to development of the upside a railway line, and lack of public utilities. The station area development requires that it's trend to large scale development of station areas, korail's direct development, deputation of specialty company to development, collaboration between local government and korail in development, diversification of process & installed facility, building multi-transfer center and one-stop transfer system. This trend caused by low profitability in development of the upside a railway line. The purposes of study are to make the system and law reflected to the property of station area development, investment in kind of needed land, and change railroad areas to high-rise and complex development, and make a forum between government and korail, etc.

• Journal of Power System Engineering
• /
• v.11 no.4
• /
• pp.32-37
• /
• 2007

Regarding the need of energy in advance and the depletion of fossil fuel energy, all researches around the world now are trying to extract energy from many alternative sources especially the renewable one. Solar, ocean tidal, wind and geothermal energy are renewable energy fields which many researches are focused on. This paper explains about effort to replace electric pump used in solar water heating system by bubble pump. The utilization of bubble pump in this system is very efficient since it needs heat energy for its operation that can be obtained easily. In addition, it can also simplify the construction of the system. Bubble pump also functions as a controller to circulate water inside the system. Before the installation of bubble pump, the special quality and performance of bubble pump should be analyzed. The result got from the analysis could show the fluctuation of water flow rate occurred because it sensitively reacts to the heat quantity. Here the heat quantity is taken from the solar that, as we know, is not stable in a whole day. Problems often occurred are the flow rate in this system is very low moreover it could be stop if the pressure exceeds the limit.

• Journal of the Korean Society for Railway
• /
• v.8 no.2
• /
• pp.145-154
• /
• 2005

Traffic accidents at highway-rail crossing result in larger social and economic damages than the accidents at the typical highway intersections. The traditional control and warning systems of the highway-rail crossing have limitations in that 1) they do not recognize the differences of the trains' arrival times because they rely on the distance-based control system, rather than the time-based one, and 2) thereby they usually cause longer delays of vehicles and pedestrians at the highway-rail crossings. The objective of this study is to develop a time-based railroad crossing control system which takes into account the speed and expected arrival time of trains. using the spot speeds and acceleration rates of trains measured at three points, the developed system was found to be able to accurately estimate the arrival time of train. VISSIM simulation package was utilized to compare system effect of the developed time-based railroad crossing control system with that of the conventional distance-based one. It was found that the developed time-based railroad crossing control system reduced the average travel time, maximum delay length, average delay time, and average number of stop-experienced vehicles as much as 7.0$\%$, 75.6$\%$, 12.7$\%$, and 60.0$\%$, respectively, compared with those from the conventional distance-based one.

• Journal of the Korean BIBLIA Society for library and Information Science
• /
• v.11 no.1
• /
• pp.45-66
• /
• 2000

Most of Korean Medical researcher is using MEDLINE which is made by National Library of Medicine in U.S. However we have not such total database of medical information. And so, we have designed medical literature article system, serial union cataloging system and interlibrary loan system as library total system. All Korean Medical Association member input bibliographic data and holding data. Medical researcher can access medical literature article system at www and then access holding data and they can use interlibrary loan system in online. The object of this total system is that medical researcher as well as medical librarian can easily retrive medical literature and gain original article.