• Proceedings of the Korean Society of Precision Engineering Conference
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• 1991.11a
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• pp.121-125
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• 1991

In order to minimize fixing error of workpieces, prismatic and cylindrical types. Modification Rule by Indexing Table and Modification Rule by NC Program are developed for machining centers by using touch trigger probes. The Modification Rule by Indexing Table means the alignment of workpiece to NC program through degree of freedoms of indexing table. The Modification Rule by NC Program is the alignment of NC program to workpiece set-up condition via the generation of NC program. A postprocessing module is also developed for generating NC-part Program (User Macro) to compensate for Machining errors in end milling and boring processes. Developed methods are verified by experiments.

• Proceedings of the KIEE Conference
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• 2008.09a
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• pp.3-5
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• 2008

Electricity Technology Management Act were carried out enactment in last 1995 to prevent illegal construction practices of electricity equipment, Later electricity supervision service is ordered to electricity supervision trade who register by law demarcated Dept of Architecture, Wish to investigate present condition and problem of current electricity supervision system in this treatise and present improvement plan for right fixing of electricity supervision system.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.543-546
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• 2000

Static and dynamic experiments were done to study on the restitution behaviors of strings. The elastic and viscoelastic model were compared. To apply a linear viscoelastic model (Kelvin model) to longitudinal behaviors of strings, static and dynamic tensile tests were done. Using their results, it should be intended to acquire damped stress (Stress related to velocity), and to calculate the viscoelastic coefficient. Fixing both ends, string was pushed by the loadcell attached to the tensile tester. The experimental results were in accordance with the calculated results using the Kelvin model acquired from the results of longitudinal tensile test. But the results of falling mass experiments, the behaviors of strings were near to elastic model. The clamping condition of strings in both sides has an effected on the value of COR. The smaller contact area, the grower the value of COR.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.04a
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• pp.14-18
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• 1996

From the experimental study of Wire-Cut EDM of die-material(SKD-11), machining characteristics such as machining rate, surface roughness and hardness have been observed and evaluated under the conditions varing pulse on time, pulse off time, peak voltage after fixing other conditions. It was found that various operating conditions have significant influences on machining rate, surface roughness. Hardness of workpiece was unaffected by operating conditions.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.04a
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• pp.173-178
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• 2003

Recently, according to the development of mechatronics industry that was composed of NT, ST, IT, RT and etc, the 1 necessity of nano-parts was increased. Because of the necessity, this research was started for improving work precision of the parts as fixing UPCU( Ultra Precision Cutting Unit)on lathe. So, in this research we executed the modeling of UPCU (Ultra Precision Cutting Unit) by the application of PZT, the relationship between the displacement of tool in UPCU and the cutting force of it has been in take a triangular position in the case of plane cutting. The modeling of system that is containing the fine displacement was performed. Also, we found like to find the optimal cutting condition through the simulation of relationship between the displacement and the cutting force.

• Proceedings of the Korean Reliability Society Conference
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• 2011.06a
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• pp.265-270
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• 2011

This paper describes a reliability/durability test of the remanufactured steering gear units. There used to be government restrictions to remanufacture certain types of automotive components regarding safety of passengers. Nevertheless, scientific approach to sustainability and remanufacturing process provided solid evidence of highly beneficial sides of reusing the products. Failure mode analysis of the steering gear unit is performed and main failure is found out. The unit is remanufactured by fixing the failure and its quality is assessed through designing a new sequence of loading events. Oil leakage is witnessed as a possible failure and its volume is measured. Conclusions based on laboratory condition durability test are given at the end.

• Proceedings of the Korean Society of Computer Information Conference
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• 2020.07a
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• pp.649-652
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• 2020

본 논문에서는 스타크래프트 게임이나 리그 오브 레전드 게임 등의 이용자끼리 실력을 겨루는 PVP 형태의 온라인 게임들에서 일어나는 어뷰징에 대해서 실태를 조사하고 이에 따른 개선 방안을 제시한다. 어뷰징에 관하여 알아보고 어뷰징이 게임과 일상에서 어떻게 작용하는지 설명하고 유저들이 어뷰징으로 인한 피해를 입는 사례를 조사하고 현재 개발사들의 조치 방안 및 유저 커뮤니티의 의견 등을 통해 실태에 대해 내용을 제시한다. 결론으로 조사한 자료를 바탕으로 어떻게 하면 어뷰징을 좀 더 방지할 수 있는지에 대한 개선 방안을 제시하고 게임 운영 차원에서 어떤 방식으로 지원해야 하는지를 제시한다.

• Korean Journal of Soil Science and Fertilizer
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• v.20 no.3
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• pp.261-268
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• 1987

A green house experiment was conducted to find out the differences in the amount of biologically fixed nitrogen and kjeldahl nitrogen on the different soil texture, kinds and amounts of fertilizer nitrogen under light (photosynthetic $N_2$-fixation) and dark (heterotrophic $N_2$-fixation) condition in submerged paddy soil. The reults obtained were summarized as follows; 1. The amount of biologically fixed nitrogen per mg carbon from different organic matter was obtained as 0.13 mg in glucose, 0.09 mg in rice straw, and 0.07 mg in refused mushroom compost and barley straw under 60 days of incubation. 2. Nitrogen fixing activities were decreased with increase of fertilizer nitrogen and those tendency was pronounced more in sandy soil with application of urea than that of ammonium sulfate. 3. The application of ammonium sulfate in sandy soil under light condition was increased the photosynthetic $N_2$-fixation and the applied urea was remarkably reduced the heterotrophic $N_2$-fixation in sandy soil. The proportion of biologically fixed total nitrogen after experiment in sandy soil was obtained as 25% for dark(heterotrophic $N_2$-fixation) and 75% for light (photosynthetic $N_2$-fixation) condition. On the other hand, very similar biological $N_2$-fixing tendency was obtained between kinds of nitrogen fertilizer and two light condition in clayey soil. 4. The kjeldahl nitrogen was remarkably decreased after experiment under dark condition with application of urea than that of light condition with ammonium sulfate, and no remarkable decreasing tendency was obtained in clayey soil between two kinds of fertilizer nitrogen. 5. The high significant positive correlationship was obtained between calculated biological nitrogen fixation by acetylene reducing activity and kjeldahl nitrogen after experiment under light (y=0.8488X-5.9632, $r=0.9928^{**}$, n=21) and dark (y=0.8795X-7.1056, $r=0.9782^{**}$, n=21) condition. In this experiment condition, conversion factors of 6:1 was obtained from biological nitrogen fixation to soil nitrogen.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.11a
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• pp.603-606
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• 2006

We present a study on the development of a practical and quantitative technique for the assessment of the structural health condition with using piezoceramic(PZT) sensors. The electro-impedance-based technique with the PZT patches is very sensitive for evaluation of the incipient and small damage in a high frequency range, and however the commonly traditional modal analysis method is effective only for considerably larger damages in low frequency range. The paper presents the technique in detecting and characterizing real-time damage on the specimen that is an aluminum plate fastened with bolts and nuts by different torques and as well a plate with a crack. By using the special arrangement of the PZT sensors, the required longitudinal wave is generated through the specimen. A large number of experiments are conducted and the different conditions of the specimens, i.e. the location and extent of loosening bolts, and the plate with a crack are simulated. respectively. Since fixing and loosening the loosened bolt is controlled by a torque wrench, we can control exactly the experiment of the different torques. Compared with the simulated healthy condition, we can find whether or not there is a damage in the specimen with using an impedance analyzer with the PZT sensors. Several indices are discussed and used for assessing the different simulated damages. As for the location of bolt loosening, the RMSD is found to be the most appropriate index for numerical assessment and as well the RMSD shows strongly linear relationship for assessing the extent of the bolt loosening, and the frequency peak shift ${\Delta}F$ is used to assess the cracked plate. The possibility of repeatability of the pristine condition signatures is also presented and the appropriate frequency range and interval are uniquely selected through large numbers of experiments.

• Journal of the Mineralogical Society of Korea
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• v.23 no.3
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• pp.219-225
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• 2010

Optimal grinding condition was examined by changing only the size of screen opening with fixing other factors to produce coal fines of particle sizes required for circulating fluidized bed gasifier. At least 85 wt% of the coal particles should fall into the size range of 0.045~1.0 mm for efficient gasification. In this study, hammer mill was used to grind Chinese low rank lignite coal following grinding condition designed by Taguchi method. The analysis of signal to noise ratio showed that optimum grinding condition for the gasifier was 3 mm in primary screen size and 1.3 mm in secondary screen size on the 95% level of significance.