• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1997년도 제25회 춘계학술대회
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• pp.33-40
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• 1997

This study was undertaken to investigate tribology characteristics of the alumina ceramics($Al_2O_3$) for the vauiation of ambient condition such as air and distilled water. The results obtained were as follows. As the sliding speed increases, the friction coefficient in the air decreased due to the reduction of sheafing stress caused by the heat accumulation of contact interface. And the friction coefficient in the distilled water decreased due to an activation of the tribochemical reaction. As the contact load increases, the friction coefficient is small in the air due to temperature rise of the contact interface. However, at the low speed side in the distilled water, the friction coefficient holds a large value due to decrease of the tribochemical reaction. The friction surface of ceramics can be protected in the air by the influence of the oxides tansfered from STB2 and also in the distilled water by the influence of the corrosive productive hydroxides.

• 한국품질경영학회:학술대회논문집
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• 한국품질경영학회 2010년도 춘계학술대회
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• pp.291-309
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• 2010

Customer satisfaction is an ever-growing concern of management throughout the world. To find the way to increase customer satisfaction, we must understand customer requirements. Kano distinguishes between three types of product requirements(must-be, one-dimensional, attractive requirement) which influence customer satisfaction in different ways when met. Timko has developed customer satisfaction(CS) coefficient based on Kano model. The CS coefficient is indicative of how strongly a product feature may influence satisfaction. In this paper, potential customer satisfaction improvement(PCSI) index was developed using Kano model and CS coefficient. The PCSI index represents how much a product feature can increase the degree of customer satisfaction when the product feature is fully fulfilled. In order to explain the meaning of PCSI index, a case study for cellular phones is done. It is also discussed how to use the index strategically.

• 품질경영학회지
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• 제38권2호
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• pp.248-260
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• 2010

Customer satisfaction is an ever-growing concern of management throughout the world. To find the way to increase customer satisfaction, we must understand customer requirements. Kano distinguishes between three types of product requirements (;must-be, one-dimensional, attractive requirement) which influence customer satisfaction in different ways when met. Timko has developed customer satisfaction(CS) coefficient based on Kano model. The CS coefficient is indicative of how strongly a product feature may influence satisfaction. In this paper, potential customer satisfaction improvement(PCSI) index was proposed using Kano model and CS coefficient. The PCSI index represents how much a product feature can increase the degree of customer satisfaction when the product feature is fully fulfilled. In order to explain the meaning of PCSI index, a case study for cellular phones is done. It is also discussed how to use the index strategically.

• 대한기계학회논문집
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• 제12권3호
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• pp.409-418
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• 1988

본 연구에서는 상반상반정리가 성립되는 선형계의 경우에 있어서 회전체를 회 전시키지 않고 시험추도 사용하지 않으며 베어링부를 가진하는 것에 의한 영향계수 측 정법을 제안한다. 대상으로 하는 영향계수는 베어링부와 각 수정점 사이의 영향계수 로서 비회전가진실험에 의해 베어링부에 힘을 가한 경우의 각 수정점에서의 비회전 영 향계수를 측정한다. 회전시험에서는 베어링부에 시험추를 부가하는 것이 구조상 곤 란하므로 각 수정점에 시험추를 부착하여 각 수정점에 힘을 가한 경우에 대한 베어링 부에서의 영향계수를 측정한다.그리고 수치계산으로 전달매트릭스법에 의해 베어링 부에 시험추를 부착하고 회전체를 회전시켜 각 수정점에서의 회전영향계수를 계산하고 실험결과와 비교한다. 상에서 구하여진 비회전과 회전영향계수의 실험결과를 비교하 므로서 비회전 영향계수의 특성을 파악하고, 이를 이용하여 탄성회전체의 평형잡이를 하는 새로운 방법을 제안한다.

• 대한기계학회논문집A
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• 제37권2호
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• pp.177-185
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• 2013

본 논문에서는 윤중감소를 고려한 이론적 새로운 탈선계수 모델을 제시한다. 본 탈선계수 모델은 열차 충돌 원인 탈선현상을 예측할 수 있는 단일 윤축의 이론적 탈선모델을 바탕으로 도출한다. 현재 국내 탈선규정에서는 플랜지 각이 $60^{\circ}$ 이고 마찰계수가 0.3인 조건을 나달식에 적용하여 탈선계수를 구한 후 안전율을 적용하여 0.8을 규정하고 있으나, 플랜지 각이 변경되면 이론적 설명이 부족하게 된다. 따라서 제시한 탈선계수 이론모델을 이용하여 탈선계수 규정 값 0.8을 이론적으로 접근해본다. 또한 국내탈선규정에서 윤중 감소율을 50%까지 허용하고 있으나 명확한 규정근거를 제시하고 있지 않다. 따라서 윤중 규정 50%감소와 탈선계수 규정 값 0.8과의 상관 관계를 앞서 제시한 탈선계수 이론모델을 이용하여 이론적으로 규명한다. 마지막으로 동역학 시뮬레이션을 이용하여 탈선계수 이론모델의 타당성을 입증한다.

• Smart Structures and Systems
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• 제25권2호
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• pp.169-181
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• 2020

Sensor placement is a crucial aspect of bridge health monitoring (BHM) dedicated to accurately estimate and locate structural damages. In addressing this goal, a sensor placement framework based on the deflection influence line (DIL) analysis is here proposed, for the optimal design of damage detection-oriented BHM system. In order to improve damage detection accuracy, we explore the change of global stiffness matrix, damage coefficient matrix and DIL vector caused by structural damage, and thus develop a novel sensor placement framework based on the Fisher information matrix. Our approach seeks to determine the contribution of each sensing node to damage detection, and adopts a distance correction coefficient to eliminate the information redundancy among sensors. The proposed damage detection-oriented optimal sensor placement (OSP) method is verified by two examples: (1) a numerically simulated three-span continuous beam, and (2) the Pinghu bridge which has existing real damage conditions. These two examples verify the performance of the distance corrected damage sensitivity of influence line (DSIL) method in significantly higher contribution to damage detection and lower information redundancy, and demonstrate the proposed OSP framework can be potentially employed in BHM practices.

• 동력기계공학회지
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• 제17권1호
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• pp.50-57
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• 2013

This describes the formulation for the free vibration of joined conical-cylindrical shells with uniform thickness using the transfer of influence coefficient. This method was developed based on successive transmission of dynamic influence coefficients, which were defined as the relationships between the displacement and the force vectors at arbitrary nodal circles of the system. The two edges of the shell having arbitrary boundary conditions are supported by several elastic springs with meridional/axial, circumferential, radial and rotational stiffness, respectively. The governing equations of vibration of a conical shell, including a cylindrical shell, are written as a coupled set of first order differential equations by using the transfer matrix of the shell. Once the transfer matrix of a single component has been determined, the entire structure matrix is obtained by the product of each component matrix and the joining matrix. The natural frequencies and the modes of vibration were calculated numerically for joined conical-cylindrical shells. The validity of the present method is demonstrated through simple numerical examples, and through comparison with the results of previous researchers.

• Journal of applied mathematics & informatics
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• 제19권1_2호
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• pp.521-525
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• 2005

Case deletion diagnostic for multiple correlation coefficient is considered. A method of detecting observations that can hide or create multicollinearity is suggested. A numerical example is given for illustration.

• 동아시아식생활학회지
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• 제4권1호
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• pp.37-47
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• 1994

A survey on images and consumption for Instant food for 450 homemakers in Ullungdo, Hansando and Daegu area were summarized as follows. 1) The tought of Homemakers food took 'easy to cook' and 'save time' as the best advantage in the image on instant food, while 'tasty' as the lowest one. It appeared that characteristic variables as household income, homemaker's education, homemaker's age, and area had influence on the image about instant food. 2) Processed food(ham, sausage)was purchased the most, while fermented food(kimchi, gochuchang) was purchased the least. It appeared that characteristics variables as household income, homemaker's education and homemaker's age had influence on the purchasing degree of instant food. 3) There were positive correlation coefficient between homemaker's image on instant food and household income(0.247) and area(0.211). There were negative correlation coefficient between homemaker's image on instant food and homemaker's age(-0.171). 4) Homemaker's purchasing degree about instant food had positive correlation coefficient with homemaker's image on instant food(0.389), household income(0.247) and area(0.211)and had negative correlation coefficient with homemaker's age(-0.190). 5) Fat intake had positive correlation coefficient with homemaker's purchasing degree(0.281) and homemaker's image(0.144) on instant food. Energy intake had positive correlation coefficient with homemaker's purchasing degree(0.206) and homemaker's image(0.138) on instant food.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1995년도 추계학술대회논문집; 한국종합전시장, 24 Nov. 1995
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• pp.154-159
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• 1995

In this study, an efficient, yet easy to use, in-situ runout identification scheme by using extended influence coefficient method is presented for active magnetic bearing(AMB) systems. It is shown experimentally that the proposed scheme successfully identifies and eliminates the troublesome runout of the well balanced AMB system in the laboratory so that a high precision spindle system can be achieved, while it is in operation.