• Tribology and Lubricants
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• 제23권3호
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• pp.109-116
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• 2007

A scroll compressor is on the increase in the use for the cooling and ambition machinery because of the advantages about high efficiency, low vibration and low noise. The design of thrust bearing for scroll compressor has depended on the experience. The lubrication considering the squeeze flow was applied for high side shell and low side shell of scroll thrust bearing. This work was based on governing fluid lubrication equation at the general coordinate. It shows the behavior for an orbiting scroll with direct numerical analysis using FDM. This study obtained the theoretical design value by finding load capacity and tilting angle of an orbiting scroll for thrust bearing in a scroll compressor. Especially this work performed the analysis about the design parameter. The program was written using Visual C++ to enhance user to change the design parameter easily. In particular the result value and the pressure profile were displayed as windows in every step for user to understand without difficulty.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.256-261
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• 2005

In this research, we propose a path-planning algorithm for an autonomous mobile robot using geographical information, under the condition that the robot moves in unknown environment. All image inputted by camera at every sampling time are analyzed and geographical elements are recognized, and the geographical information is embedded in environmental map. The geographical information was transformed into 1-dimensional evaluation value that expressed the difficulty of movement for the robot. The robot goes toward the goal searching for path that minimizes the evaluation value at every sampling time. Then, the path is updated by integrating the exploited information and the prediction on unexploited environment. We used a sensor fusion method for improving the mobile robot dead reckoning accuracy. The experiment results that confirm the effectiveness of the proposed algorithm on the robot's reaching the goal successfully using geographical information are presented.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1992년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 19-21 Oct. 1992
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• pp.272-275
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• 1992

Recently, the digital circuit technique has had great success and gained importance in all industries. For the measurement of degree of freshness of plant and animal's tissue, many devices has been developed. But it's data was inaccurate and it had difficulty in making database because it was depend on analog circuit technique. The purpose of this paper is the development of a device based on digital circuit for measurement of freshness degree of wet fish such that its accuracy is very trustworthy and it can be measured in a short time. The device is developed by using micro-computer with some interface modules of A-D/D-A converter and digital circuit with IC modules and its effectiveness has been evaluated through two experimental results of electrical Q-value test and chemical K-value test.

• 한국IT서비스학회지
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• 제7권3호
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• pp.115-127
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• 2008

Many problems making the use and management of patents arduous is caused by the difficulty in knowing the proper value. This study has suggests the methods to evaluate the value of patents by using a quantitative assessment scale as an alternative or complementary measure instead of the existing subjective evaluation tools. This study is to find a method to determine the capability and level of research and establish the scheme of use and management of patents by using the citation index as a quantitative assessment measure. The data used in this paper has been obtained from a public-sector R&D institute, the K-Institute in Korea.

• 한국생산제조학회지
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• 제7권5호
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• pp.38-45
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• 1998

The Z-map model which is quite similar to the non-parametric patch is widely used to describe the shape of a surface because of its simplicity. Despite the inherent advantage of z-map model. it has drawbacks that there exists difficulty in expressing the vertical walls and its related contact treatment method. In the region of vertical walls, there is a convergence problem in searching the contact point. In this study a contact point finding scheme is presented, based on the z value of the z-map model on the sheet normal direction. To show the utility of this scheme a compared with the experimental results. The effects of the Z-map grid distances and the interpolations of the inside Z-map value are also discussed.

• 대한안전경영과학회지
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• 제3권2호
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• pp.113-121
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• 2001

Today, facilities are composed of many complex components or parts. Because of this characteristics, the frequency of failures is decreasing, but the strength of failures is increasing; therefore, the failure analysis about many complex components or parts was needed. In the former research about Fault Tree Analysis, failure data of similar facilities have been used for forecasting about target system or components, but in case that the system or components for forecasting failure is new or qualitative and quantitative data are given simultaneously, there are many difficulty in using Fault Tree Analysis with this incorrect failure data. Therefore, this paper deal with the Fault Tree Analysis method which be applied with Fuzzy theory in above case. In case that , therefore, if there is no the correct failure data, it is represented a system or components as qualitative variable. subsequently, it converted to the quantitative value using fuzzy theory, and the values used as the value for failure forecast.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2006년도 춘계학술대회 논문집
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• pp.288-292
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• 2006

Usually, equations that calculate ground resistance of earth electrode was already informed well by form of earth electrode. But, when apply on the spot because general expressions are very insufficient at point that calculate exact ground resistance value by variation of earth electrode, and constant value that corrective coefficient for ground resistance calculation is fixed regardless of change of the earth resistivity specially is presented, it is actuality that difficulty is. Therefore, in this study, about these problem, proposed corrective coefficient for calculation of ground resistance according to change of the earth resistivity.

• 대한원격탐사학회지
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• 제19권5호
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• pp.341-349
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• 2003

The so-called B-method, a simplified surface energy budget, permits calculation of daily actual evapotranspiration (ET) using remotely sensed data, such as NOAA-AVHRR. Even if the use of satellite data allows estimation of the albedo and surface temperature, this model requires meteorological data measured at ground-level to obtain the other inputs. In addition, a difficulty may be occurred by the difference of temporal scales between the net radiation in daily scale and instantaneous measurement at midday of the surface and air temperatures because the data covered whole day are necessary to obtain accumulated daily net radiation. In order to solve these problems, this study attempted a modification of B-method through an extension of hourly ET value calculated using a complete instantaneous inputs. The estimation of the daily apparent ET from newly proposed system showed a root mean square error of 0.26 mm/day as compared the output obtained from the classical model. It is evident that this may offer more rapid estimation and reduced data volume.

• 산업경영시스템학회지
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• 제27권4호
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• pp.110-116
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• 2004

ABC analysis is the process of dividing inventory items into three classes according to their monetary usage so that managers can focus on items that have the highest monetary usage value, and has been widely used in practice since its development in 1950. However, the original criterion, monetary usage value, can no longer be the only rational criterion. Applying Analytic Hierarchy Process, we develop a new method to classify inventory items by considering such operationally/strategically important criteria as annual dollar usage, lead time, supplier's capacity, defective rate, difficulty of purchasing and unit price. A case study is performed applying the method to the field data from a company which produces electrochemical products.

• 복식문화연구
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• 제9권5호
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• pp.700-711
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• 2001

The purpose of this study was to investigate the differences in the method of patternmaking, difficult in draft of patternmaking, fit in sleeve, aesthetic view, fashionableness in the five types of two-piece sleeve under the controled situation. Five types of two piece sleeve that were originated from five countries including domestic companies which called A type, B type, C type, D type, and E type were used. In order to conduct the experiment fur the study, 10 persons who were well organized about the patternmaking drafted 5 types of sleeve and were tested for the differences in the method of patternmaking, difficulty in draft of patternmaking. Another panel were tested for fit in sleeve, aesthetic view, fashionableness in the five types of two-piece sleeve in jacket under the controled situation. The results of this study were as followed 1. C type was needed height of armhole in bodice and D type was needed height of armhole and width of armhole in bodice as well as all parts of sleeve measurements to draft patternmaking. 2. There were significant differences of the items such as cap height, ease amount around sleeve cap, width of sleeve, forwardness of sleeve and the length of elbow line of the five types patternmaking drafted. 3. There were significant differences of difficulty in draft of the five types of patternmaking. C type and E type were easier to draft. 4. There were significant differences in fitness of the sleeves in jacket. C type and E type were more fit. 5. There were significant differences in aesthetic view. A type, B type and E type were more aesthetic under the situation. 6. There were significant differences in fashionableness in jackets. A type and E type were more fashionable under the situation.