• Transactions of Materials Processing
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• v.19 no.6
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• pp.357-362
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• 2010

Dry sliding wear behavior of pure Fe and Cu which have BCC and FCC crystal structure, respectively, was investigated. The wear characteristics of the pure metals with different crystal structure were compared. Dry sliding wear tests were carried out using a pin-on-disk wear tester at various loads under the constant sliding speed condition of 0.15 m/s against a silica ball at room temperature. Sliding distance was fixed as 600 m for all wear tests. Wear rate of a specimen was calculated by dividing the weight loss of the specimen after the test by the specific gravity and sliding distance. Worn surfaces and wear debris were analyzed by SEM. The wear of both pure Fe and Cu proceeded with surface deformation, resulting in similar wear rates despite of their structure difference under the current test conditions. Wear rates of both metals were low if the surface deformation due to wear forms thick surface-deformation layer that is strain hardened beneath the wearing surface. The pure Cu specimens showed a lot of oxides on the worn surface when tested at low loads less than 5 N, which resulted in very low wear rate.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.05a
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• pp.385-388
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• 2009

Dry-sliding-wear behavior of Fe-18Cr-l0Mn steel with various carbon and nitrogen contents was characterized, and the effect of carbon and nitrogen contents on the wear was investigated. Dry sliding wear tests of the steel were carried out at room temperature against an AISI 52100 bearing steel ball using a pin-on-disk wear tester. Applied wear loads were varied from 10 N to 100 N, and the sliding distance was fixed as 720 m. Worn surfaces and the wear debris of the steel were examined using an SEM to find out the wear mechanism. It was found that the Fe-18Cr-10Mn with both carbon and nitrogen exhibited superior wear resistance to the steel with only nitrogen. The wear resistance of the Fe-18Cr-10Mn-xC-yN alloy increased with the increase of the carbon content. The excellent wear resistance of the Fe-18Cr-10Mn-xC-yN alloy was explained by the increased strain-hardening capability with the interstitial atoms.

• Journal of Korean Society of Water and Wastewater
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• v.33 no.6
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• pp.447-456
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• 2019

This study focused on natural organic matter and trihalomethane removal by ozonation with various ferrous concentration in surface water. Ozonation is more affected by injection concentration than reaction time. dissolved organic carbon removal rates in ozonation increased with the increase in ferrous concentration. The highest removal was obtained at 6 mg/L of ferrous concentration. When 1 mg/L of ferrous was added with 2 mg/L of ozone concentration, it was found to be a rapid decrease in specific ultraviolet absorbance at the beginning of the reaction because ferrous acts as a catalyst for producing hydroxyl radical in ozonation. As ozone concentration increased, trihalomethane formation potential decreased. When 2 mg/L of ozone was injected, trihalomethane formation potential was shown to decrease and then increase again with the increase in ferrous concentration.

• The Journal of Korea Robotics Society
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• v.15 no.3
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• pp.240-247
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• 2020

This paper presents a novel knitted data glove system for pattern classification of hand posture. Several experiments were conducted to confirm the performance of the knitted data glove. To find better sensor materials, the knitted data glove was fabricated with stainless-steel yarn and silver-plated yarn as representative conductive yarns, respectively. The result showed that the signal of the knitted data glove made of silver-plated yarn was more stable than that of stainless-steel yarn according as the measurement distance becomes longer. Also, the pattern classification was conducted for the performance verification of the data glove knitted using the silver-plated yarn. The average classification reached at 100% except for the pointing finger posture, and the overall classification accuracy of the knitted data glove was 98.3%. With these results, we expect that the knitted data glove is applied to various robot fields including the human-machine interface.

• 한국IT서비스학회:학술대회논문집
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• 2003.05a
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• pp.171-179
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• 2003

기업들은 IT 아웃소싱을 통하여 급속한 IT의 변화에 대하여 신속히 적응하고, IT 구축 및 운영 비용을 효율적으로 절감하고 있으며, 특히 IT의 전략적 가치가 주요해짐에 따라 아웃소싱을 통하여 서비스 품질을 향상시키고, 핵심역량에 집중하고자 노력하고 있다. 공기업에서도 최근의 정부의 민간위탁에 대한 적극적인 제도 지원에 의해 IT 아웃소싱이 활성화되고 있으나, 이에 따른 의사결정을 위해서는 민간 부문과는 다른 요인들이 고려되어야 한다. 지금까지 많은 연구가 주로 위험요인, 조직요인, 도입목적 등의 단편적인 요인들을 제시하는 수준이었기 때문에 실질적인 의사 결정에 있어서는 활용성이 부족하므로, 본 연구에서는 실질적인 의사결정을 지원할수 있도록, 기존 연구들을 바탕으로 IT 아웃소싱 의사 결정의 전범위에 걸친 체계적인 의사결정 모형을 제시하고, 각 의사결정단계에서 우선적으로 고려해야 하는 요인들을 구체적으로 나타내고자, IT 아웃소싱의 의사결정 영역을 네가지로 분류하고, 고려해야 할 55개의 요인들을 문헌연구들을 통하여 도출하였다. 그리고, 11명의 전문가 집단을 구성하여 각 의사결정 영역별로 주요한 요인들을 도출하였다. 또한, 공기업 M사 사례를 통하여 IT 아웃소싱 의사결정 프로세스의 실례를 보여줌으로써 향후 활용방안을 제시하고 있다.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.12 no.10
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• pp.901-907
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• 2000

The conceptual determination of mixed-refrigerant (MR) for a closed Joule-Thomson cryocooler is described in this paper. The thermodynamic cycle design was mainly considered to develop a cryocooler by using a compressor of domestic air-conditioning unit. The target cooling performance of the designed cryocooler is 10 W around 70 K with less than 5 kJ/kg enthalpy rise. The systematic approach of choosing a proper refrigerant among 20 different kinds of mixture for such cryogenic temperature was introduced in detail. The main components of the cryocooler are compressor, evaporator, oil separator, after-cooler, counterflow heat exchanger, and J-T expansion device. Due to the limitation of the compressor operation range, the temperature after the compression was limited below $117^{\circ}C$ (390 K) and the temperature before compression was restricted above $5^{\circ}C$ (278 K). 20 atm of discharging pressure (high pressure) and less than 3 atm suction pressure (low pressure) were the design conditions. The inlet temperature of a counterflow heat exchanger in the high Pressure side was about 300 K. The proper composition of the mixed refrigerant for the designed J-T cryocooler is 15% mol of$ N_2, 30% mol of $CH_4,\; 30% mol\; of C^2H^ 6,\; 10%\; mol\; of\; C_3H_8\; and \;15%\; mol\; of\; i-C_4H_10$.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.1
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• pp.71-78
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• 2016

This paper proposes the new electric power demand forecast model which is based on an artificial neural network and considers time and weather factors. Time factors are selected by measuring the autocorrelation coefficients of load demand in summer and winter seasons. Weather factors are selected by using Pearson correlation coefficient The important weather factors are temperature and dew point because the correlation coefficients between these factors and load demand are much higher than those of the other factors such as humidities, air pressures and wind speeds. The experimental results show that the proposed model using time and seasonal weather factors improves the load demand forecasts to a great extent.

• The Research Journal of the Costume Culture
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• v.27 no.6
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• pp.582-598
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• 2019

Intermedia is a term that refers to the convergence of different media. It has not only enabled the delivery of brand message but also developed interactive communication in a contemporary fashion show context. This study investigates the presentation methods of contemporary fashion shows affected by intermedia. We examined the research and theory related to intermedia and fashion shows by accessing articles since the 2000s concerning 252 shows by 30 designers that tended to demonstrate the use of intermedia. Our analysis highlighted four particular characteristics: "medium scalability" (the unity of art and fashion and the unity of life and fashion); "synesthetic flow" (the audience's emotional immersion, represented by the actual performance and performances of the models); "participatory accessibility" (performance participation through action and instrumental support); and "immaterial symbolization" (an intuitive symbol that emphasizes both the direct outward appearance and the metaphorical symbolism so that the object is expressed in a figurative sense). From these results, we identified considerable synergy between the characteristics of intermedia and contemporary fashion shows. Therefore, it might be useful to conduct an experimental study on this area of research.

• The Journal of Churna Manual Medicine for Spine and Nerves
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• v.5 no.2
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• pp.1-8
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• 2010

Objectives : The propose of this study was to observe the correlation between Cervical hypolordosis and radiological result. Methods : We randomly selected among the 110 patients with X-ray and C-spine MRI films who have visited Jaseng Hospital of Oriental Medicine with neck pain. Radiographic measures of cervical lordosis and herniated disc were collected, and statistically analyzed. Results : In this study, if the finding of a X-ray showed straightening of cervical lordotic curve, based on MRI finging, the amount of herniation was more severe. Conclusions : There was a significant correlation between Cervical hypolordosis and herniated disc. Hypolordosis group complained a severe herniated disc.

• Journal of Ocean Engineering and Technology
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• v.29 no.2
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• pp.199-206
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• 2015

Regular high-strength carbon steel is currently the most commonly used pipe material for onshore and offshore pipelines. The corrosion of offshore pipelines is a major problem as they age. The collapse of these structures as a result of corrosion may have a heavy cost is lives and assets. Therefore, their monitoring and screening is a high priority for maintenance, which may ensure the integrity and safety of a structure. Monitoring risers and subsea pipelines effectively can be accomplished using eddy current inspection to detect the average remaining wall thickness of corroded low-alloy carbon steel pipelines through corrosion scaling, paint, coating, and concrete. A test specimen for simulating the offshore pipeline is prepared as a standard specimen for an analysis and experiment with differential bobbin eddy current sensors. Using encircling coils, the signals for the defect in the simulated specimen are analyzed and evaluated in experiments. Differential bobbin eddy current sensors can diagnose the defects in a specimen, and experiments have been carried out using the developed bobbin eddy current sensor. As a result, the most optimum coil parameters were selected for designing differential bobbin eddy current sensors.