• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.1401-1409
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• 2007

This paper presents a detecting technique for the improvement in quality by appling the various vibrational characteristics theory. The object of this study is to objectively point out faulty gear by developing the program which can be used to analyze and predict the vibrational characteristics caused by gear wear, deformation and nick of auto-transmission. The fault detection methods by vibrational signal analysis of gear have been progressed in the various fields of industry. These methods have the advantage of being easy to attach the accelerometer without discontinuance of the structure. But not all the methods are efficient for finding early faults. So in the thesis, we completed development of the inspection system of vibration by appling the most efficient detecting methods and verified the system's reliability through experiments.

• Journal of the Korean Society of Costume
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• v.26
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• pp.123-143
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• 1995

Clothing as one of elements of culture has been interwoven with cultural diffusion, and accompanied the most visible change. In this paper, it was focused that the process and the characteristics of western clothing adop-tion of Korea from 1876 to 1945 corelating with cultural diffusion theory. They were analyzed through the change of clothing reformation system by government, school uniform, and social phenomenon. The finding of this paper were as followings; 1. The process of western clothing adoption was forcibly demanded by Japan, therefore influenced by Japan. 2. The clothing reformation which was forced to accept western style was confronted by complex of cultural, psychological and economical resistance. 3. The fashion leaders of this period were Korean students studying abroad, diplomatic officials, members of the armed forces, government officials, students of western educational systemed school, and lady of evangelist. 4. Man adopted western clothing earlier than woman. 5. Western clothing adoption was took precedence in case of formal wear, diplomatic official's attire, military uniform, and school uniform. 6. In this process, we can find 'transculturation' by Malinowski and 'reinter-pretation' by Herskovits. 7. This process was a kind of 'reorientaion'. 8. The change of clothing which was affected by the tradition, for example, robe for the ancestral rites was evolutionary than others. 9. Clothing elements based on mental or internal characteristics like which clothing was hardly changed by compulsion or extortion. 10. The external trends of clothing change during this period were simplicity, utility, and decrease of status symbols.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.12
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• pp.3109-3117
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• 1994

To operate a flexible mechanism in high speed its weight must be reduced as far as the structural strength does not decrease too much, but a light-weighted mechanism causes undesirable elastodynamic responses deteriorating the system performance. Besides, clearance within the connections of mechanisms causes rapid wear, increased noise and vibration. Even if the problems described above must be considered in the initial design stage, there has been no effective design process which takes account of the correlation between dynamic characteristics of flexible mechanism and the clearance effect at the joint. In this study, the generalized elastodynamic governing equations which include dynamic characteristics and boundary conditions of flexible mechanism are derived by variational calculus and solved by using FFM theory. To take the clearance effect at joint into account a new dynamic model is presented and also the method of modified stiffness/damping matrix is proposed to activate the dynamic clearance model, which cooperates with the developed governing equation very easily. As the results of this study, the proposed method(modified stiffness/damping matrix) to calculate clearance effect was proved to be superior to the existing one(force reaction method) in solution convergency and calculation performance. Besides this method can be easily adopted to the complex shape joint without calculation of reaction force direction.

• Plant Journal
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• v.13 no.1
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• pp.30-36
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• 2017

During the start-up of 500 MW class coal-fired power plant, abnormal shaft vibration was occurred on bearings installed on both side of high and intermediate pressure steam turbine. Shaft vibration was analyzed to investigate the reason and find the resolution, based on well-known theory in this study. Typical vibration characteristics which occur when rotating parts contact with stationary parts were observed at the analysis of frequency, amplitude and phase angle. The reason of abnormal vibration was assumed to be rub and internal parts wear was observed during repair period. As a result of applying low speed turning and balancing for resolution of abnormal vibration, balancing was more effective for rub removal. So balancing could be excellent resolution in the case of abnormal vibration which is similar to this study.

• The Research Journal of the Costume Culture
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• v.18 no.3
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• pp.488-498
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• 2010

This study was intended to develop a multi-purpose, multi-functional design for safety vest to enhance the safety and user's availability. With a limited scope to LED-applied safety vest, this study contemplates on the problems of safety vest on the market and directions for design development with a view to develop its prototype. This is a significant study because it has been conducted concerning a prototype, a cut above the study method of constructing a basic theory. For study method, theoretic considerations on LED and safety vest are followed by case study for LED-applied safety vest currently on the market to draw out problems. Then, solutions for problems with LED safety vest will be found, while planning for a design direction in consideration of safety, functionality and beauty. Scope of study was limited to cases of LED safety vests currently on sale online and offline, excluding cases of common-form luminosity such as HB luminous vest without LED. Accordingly, results of study will help develop the prototype for LED safety vest with an increase of the wearer's safety, and be used as a basic data for developing high-value-added fashion prodcts to meet his aesthetic sense and functionality. This study has limitations. Restricted scope for LED-applied safety vest should be extended to an outdoor wear in follow-up research for the foundation of higher value added.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.445-450
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• 2003

This study was performed 10 develop the accelerated life test method using Weibull-IPL(Inverse Power Law) model for mechanical components. Weibull-IPL model is concerned with determining the assurance life with confidence level and the accelerated life test time From the relation of weibull distribution factors and confidence limit, the testing times on the no number of failure acceptance criteria arc determined. The mechanical components generally represent wear and fatigue characteristics as a failure mode. IPL based on the cumulative damage theory is applied effectively the mechanical components to reduce the testing time and to achieve the accelerating test conditions. As the actual application example, accelerated life test method of agricultural tractor transmission was described. Life distribution of agricultural tractor transmission was supposed to follow Weibull distribution and life test time was calculated under the conditions of average life (MTBF) 3,000 hours and 90% confidence level for one test sample. According to IPL, because test time call be shorten in case increase test load test time could be reduced by 482 hours when we put the load 1.1 times of rated load than 0.73 times of rated load that is equivalent load calculated by load spectrum of the agricultural tractor. This time, acceleration coefficient was 11.7.

• Journal of the Korean Society of Costume
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• v.25
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• pp.157-169
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• 1995

The confucianism, the Taoism, the Budd-hism and the Folk-Faith actually coexisted and all of them had also widespread infuluence on the Chosun Society. This thesis is designed to study symbol of Color Scheme expressed in the clothing of Chosun dynasty. For this thesis I examined records of Royal archives, books containing lifestyle of Chosun dynasty, genre paintings, documantary pain-tings, excorcist clothing and existing remains. And I synthetically studied symbol of the Clothing Color Schemes in Chosun dynasty on the bases of theoretical researches. The result were as follows. There were many cases of 1. Upper·lowergarments : Red-Blue, White-Blue, White-Blue Color Schemes. 3. Exorcist clothing : Red-Red, Blue-Yellow, Blue-Blue Color Schemes. 4. Multy-colored stripes : Same color arrange-ments were avoided in Color Schemes. In the case of Green Wonsam, Blue-Red-Yellow-White Clothing Color Scheme was obvious. 5. Dance wear : Red-Blue, Yellow-Red Color Schemes. Generally more than anything else Blue-red Clothing Color Scheme was widely used. Be-sides Blue-Red Color Scheme, there were also many cases of Red-Yellow, White-Blue Cloth-ing Color Schemes. As a whole, compatible Color Schemes were more often used than in-compatible Color Schemes were used with various symbols that were based on color concept of Yin-Yang O-haeng, Tae-il theory Folk-Faith and so forth in Chosun dynasty.

• International Journal of Precision Engineering and Manufacturing
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• v.6 no.3
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• pp.51-55
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• 2005

This study addresses the contamination sensitivity test of a typical fuel pump for an automotive vehicle. The objective of the study is to find the contamination sensitivity coefficient of a fuel pump on specific contaminant particle sizes so that an optimal fuel filter could be selected. To achieve the objective, the degradation of discharge flow rate of the fuel pump is measured under the experiments of various contaminants size ranges of ISO test dust up to $80\;{\mu}m$. The fundamental theory of contamination sensitivity is introduced and the contamination sensitivity coefficients are estimated using the experimental data. Maximum contamination sensitivity coefficient of $5\chi\;10^{-6}\;L/min{\cdot}Ea$ is found in the contaminant size range of $40\;{\mu}m\~50\;{\mu}m$. The magnified picture of the surface of vane disc reveals that the abrasive wear is the principal cause of discharge flow rate degradation. Hence, this study reveals that a high efficiency filter for contaminant particles especially in the size range of $30\;{\mu}m\~70\;{\mu}m$ especially should be used to maintain the service life of the fuel filter.

• Journal of Advanced Marine Engineering and Technology
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• v.11 no.4
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• pp.50-58
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• 1987

At present it has been cleared that even carefully polished surfaces have irregularities on them which are large compared with molecular dimensions by the progress of a scanning electron microscope. When two solids are placed together, the real area of contact is very small, so that the local pressure is high and, in general, exceeds the yield pressure of the metal. Plastic flow of the solid occurs at the summits of the irregularities so that the real area of contact is proportional to the applied load. There is adhesion at local resions of contact and the friction is, in a large measure, the force required to shear them. On this view point, the friction experiment with different specimens which are carbon steel, copper and constantan was attempted to know the characteristics of temperature change in contact with different metals. Various experiments are summerized as follows; 1) With metals of high melting point, momentary 1000 .deg. C may last below $10^{-4}$ of a second. It is thought that above phenomena back up previous adhesion theory in wear. 2) As a general rule, surface temperature in contact with different metals becomes high when the load increases while it is observed that surface temperature decreases when the load increases with shapes of specimens.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.7 no.2
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• pp.23-30
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• 2008

As a basic machining process, turning is a widely used machining process in which a single-point cutting tool removes material from the surface of a rotating material. A common method of evaluating machining performance is to measure the surface roughness. In a turning operation, it is important to select cutting conditions for achieving high cutting performance. As a rule, cutting conditions can be classified into feed rate, depth of cut and insert radius. While cutting process even though cutting conditions are optimized, the average roughness can be deterioration due to wear of the cutting tool edge. In this study, the aim is to maintain the average roughness even though the cutting condition is irregularly changing within the predictable range due to the working environment. First, the surface roughness model influenced by cutting conditions is constructed based on the experimental results in a turning operation, Second, applying the sliding mode control theory to the turning operation model which is composed of the surface roughness model and the motor transfer function, the surface roughness is closed to the desired value. Finally, the effectiveness of this approach is demonstrated through the computer simulation.