• 한국동물학회:학술대회논문집
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• 한국동물학회 2000년도 한국생물과학협회 학술발표대회
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• pp.264.2-264
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• 2000

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• 한국광과학회:학술대회논문집
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• 한국광과학회 2005년도 제12회 학술대회 논문초록
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• pp.90-90
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• 2005

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2002년도 proceedings of the second asia international conference on tribology
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• pp.425-426
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• 2002

Lineal and angular movements of many engine components make the lubricant absorb air and the aerated lubricant greatly influences the clearance performance of contacting behaviors of engine components such as big-end bearing, cam and tappet, etc. This study investigates the behaviors of aerated lubricant in the gap between con-rod bearing and proceeding which is one of the most frictional energy consuming components in the engine. Our assumption for the analysis of aerated lubricant film is that the film formation is influenced by the two major factors. One is the density characteristics of the lubricant due to the volume change of lubricant by absorbing the bubbles and the other is the viscosity characteristics of the lubricant due to the surface tension of the bubble in the lubricant. In our investigation, it is found that these two major factors surprisingly increase the load capacity in certain ranges of bubble sizes and densities. Frictional forces are also influenced by the aerated bubble size and density, which eventually enlarge the shear resistance due the surface tension, Modified Reynolds' equation is developed for the computation of fluid film pressure with the effects of aeration ratio under the dynamic loading condition. From the calculated load capacity by solving modified Reynolds' equation, proceeding locus is computed with Mobility method at each time step.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 춘계학술대회 논문집
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• pp.1023-1030
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• 2011

The purpose of this article is to find out and analyze the diverse factors that are incurring stress to the railway drivers, and to depict the relationship among personality, job stress, job satisfaction, and accidents. To attain this purpose, the authors designed the questionnaire based on in-depth interview, scrutinized the factors of stressors, and statistically tested the study themes on the moderating effects of Personality Factors such as Locus of Control, Self-Efficacy, and Organization-Based Self Esteem on the relationship between Job Stressors and Job Satisfaction/Accidents, for the 212 samples received from KORAIL, Seoul Metro, and Seoul Metropolitan Rapid Transit. Resultedly, one of the findings indicate that certain aspects of a driver's personalities, as measured by locus of control, self-efficacy, and organization-based self esteem play important roles in predicting the level of job satisfaction, job stress and accidents.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2000년도 춘계학술발표대회
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• pp.592-595
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• 2000

In human chromosome, a short sequence of DNA has been repeated a number of times. These repeats are called variable number of tandem repeat(VNTR) or short tandem repeat(STR) which has short repeat core. VNTR and STR are used in the field of forensic science, evolution, and anthropology. In this work, we examined allele frequencies of 3 VNTR(YNZ22, NeuR, D21S11) and one STR(Humth01) in a Korean population sample by polymerase chain reaction(PCR) followed by high-resolution polyacrylamide gelelectrophoresis(PAGE) with silver staining. Subsequently, the polymorphism information content(PIC) was calculated : the highest PIC was observed for the NeuR locus(0.95680) and lowest for the Humth01 locus(0.75809).

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2002년도 제35회 춘계학술대회
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• pp.185-192
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• 2002

This paper focused on the dynamic behavior of camshaft in a direct acting type valve train system. To investigate camshaft behavior, transient vibration analysis is performed by using the transfer matrix method. The camshaft is treated as lumped mass system supported by spring and damper. Front the presented analytical model, we could predict dynamic behavior of camshaft, shaft locus within bearing and bearing load. The presented mode and results will be very helpful to design the optimal camshaft and valve train system.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.174-179
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• 2004

The paper deals with gravitational effect on dynamic stability of a cantilevered pipe conveying fluid. The eigenvalue branches and modes associated with flutter of cantilevered pipes conveying fluid are fully investigated. Governing equations of motion are derived by extended Hamilton's principle, and the solutions are sought by Galerkin's method. Root locus diagrams are plotted for different values of mass ratio of the pipe, and the order of branch in root locus diagrams is defined. The flutter modes of the pipe at the critical flow velocities are drawn at every one of the twelfth period. The transference of flutter-type instability from one eigenvalue branches to another is investigated thoroughly.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.1428-1431
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• 1996

This paper proposes an anti-swing control law for a 2 degrees of freedom overhead crane. The dynamic model of a 2 degrees of freedom crane is highly nonlinear and coupled. The model is linearized and decoupled for each degree of freedom of the crane for small motions of the load about the vertical. Then a decoupled anti-swing control law is designed for each degree of freedom of the crane based on the linearized model. The control law consists of a position control loop and an swing angle control loop. The position loop,. is designed based on the loop shaping method and the swing angle loop is designed via the root locus method. Finally, the proposed anti-swing control law is implemented and evaluated on a 2 degrees of freedom prototype crane.

• 한국벤처창업학회:학술대회논문집
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• 한국벤처창업학회 2018년도 춘계학술대회
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• pp.191-197
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• 2018

The purpose of the study is to identify social entrepreneurship intentions among university students in Uzbekistan focusing on the Tashkent State University of Economics(TSEU) as a study area. A 47 item questionnaire was distributed to 371 students of TSUE students in Uzbekistan by using convenience sample method. From a total of the 371 respondents, 278 (74.93%) were male, 93 (25.07%) were females and the average age of the respondents was approximately 22 years. The result indicates that the model in this study accounts for 67,7% of the variance in interpreting the social entrepreneurship intention. This study makes a contribution to the social entrepreneurship research area by including factors such as risk taking propensity, internal locus of control, moral obligation, self-efficacy and empathy as antecedents of the theory of planned behavior that also explains social entrepreneurial intention formation.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.513-518
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• 2001

As the machining depth increases, the drilling torque increases and fluctuates and the risk of drill failure also increases. Hence, drilling torque control is very important to prevent the drill from failure. In this study, a PID controller was designed to control the drilling torque in a machining center. The plant including the feed drive system, cutting process, and spindle system was modeled for controller design. The Ziegler-Nichols rule was used to determine the controller gain and control action times. The root locus plot was used to tune the controller gain for a certain cutting condition. Also, suggested was a simple method to obtain the tuned controller gain for an arbitrary cutting condition not using the Ziegler-Nichols rule and root locus plot. The cutting torque control, performance of the designed controller and the effect of gain tuning on the control performance were examined.