• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11a
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• pp.297-303
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• 2001

This research presents an analytical model to characterize the ball bearing vibration due to the waviness in a rigid rotor supported by multi-row ball bearings considering centrifugal force and gyroscopic moment of ball. The effects of centrifugal force and gyroscopic moment are introduced to the kinematic constraints and force equilibrium equations. The waviness of ball and races is modeled by the superposition of sinusoidal function and it is introduced to position vectors of race curvature center to use the Hertzian contact theory in order to calculate the elastic deflection and nonlinear contact force resulting from the waviness while the rotor has translational and angular motion. They can be determined by solving the nonlinear equations of motion with five degrees of freedom by using the Runge-Kutta-Fehlberg algorithm. The accuracy of this research is validated by comparing with the results of the prior researches. It characterizes the vibration frequencies resulting from the various kinds of waviness in rolling elements, the harmonic frequencies resulting from the nonlinear load-deflection characteristics of ball bearing resulting from the waviness interaction.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.11 no.7
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• pp.275-286
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• 2001

The research presents an analytical theory to calculate the characteristics of the bal bearing with waviness in its rolling elements considering the centrifugal force and gyroscopic moment of bal. The effects of centrifugal force and gyroscopic moment are introduced to the kinematic constraints and force equilibrium equations. and the waviness of rolling elements is modeled by sinusoidal function to calculate the contact force at each ball. The numerical solutions of governing equation of berating due to waviness are calculated by using the Newton-Raphson method. The accuracy of the research is validated by comparing the contact force. contact angle in case of considering the centrifugal force and gyroscopic moment of bal and the contact force and vibration frequencies in cases of considering waviness with the prior researches respectively. It investigates the stiffness, contact force. displacement and vibration frequencies of the ball bearing considering not only the centrifugal force and gyroscopic moment of ball but also the waviness of the rolling elements.

• Journal of KIISE:Computer Systems and Theory
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• v.26 no.12
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• pp.1529-1538
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• 1999

광대역 액세스 망은 B-ISDN 환경에서 다양한 유형의 가입자들을 서비스 노드로 집선하는 기능을 수행한다. ITU-T의 SG13에서는 광대역 액세스 망과 서비스 노드 사이에서 ATM 자원의 동적인 할당 및 해제를 위하여 연결 제어 프로토콜의 표준화를 수행하고 있다. ATM 연결의 설정을 위한 연결 제어 프로토콜과 신호 프로토콜의 연동 기능은 서비스 노드에서 수행되며, ITU-T에서는 순차적 연동 모델을 채택하고 있다. 순차적 연동 모델은 SN에서 각 프로토콜의 절차가 순차적 방식으로 연동되므로 연결 지연이 크다. 본 논문에서는 광대역 액세스 망의 도입으로 인한 연결 설정 지연을 최소화하기 위하여 병렬형으로 수행되는 연동 모델을 제시하였다. 그리고 본 논문에서 제안한 병렬형 연동 모델의 성능 분석을 통하여 순차적 연동 모델과의 연결 설정 지연 및 완료비에 대한 비교, 분석을 수행하였다. 성능 분석에서 사용된 워크로드 파라미터는 RACE MAGIC 프로젝트의 결과를 적용하였다. Abstract In B-ISDN environment, various subscribers are concentrated into a service node via a broadband access network. The SG13 of ITU-T is standardizing a connection control protocol which provides dynamic allocation of ATM resources between an access network and a service node. To establish an ATM connection, interworking functions between the connection control protocol and the signaling protocol are performed at the service node. ITU-T adopts the sequential interworking model. In this paper, we propose the parallel interworking model which minimizes the overall connection setup delay by introducing the access network. Using the performance analysis, we compare our proposed parallel model with the existing sequential model in terms of connection setup delay and completion ratio. The workload parameters of RACE MAGIC project are applied to the analysis and simulation.

• Survey Research
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• v.11 no.1
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• pp.63-85
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• 2010

This study defines the substance and multi-dimension of emotional reactions which Koreans have toward foreigners to find the starting point of change in values which is an inevitable task in this multi-cultural society. The results indicate that the Bogardus scale which has been used to measure the social distance toward the minority race is found to have limitations in explaining the closed attitude of Koreans toward 'nation' and 'kinship through marriage'. To supplement such limitations, exploration on attitudes toward foreigners from different native places is performed based on the 'evaluation', 'power' and 'activity' dimensions of the Affective Control Theory. As a result, Americans are highly evaluated in all three dimensions while Japanese are evaluated low in the 'evaluation' dimension and high in the 'power' and 'activity' dimensions. North Korean defectors and ethnic Koreans from China (the Chosun race) are high in evaluation but low in other dimensions. West Asians are evaluated low in all three dimensions. By comprehending the influencing factors and the relative influence of social distance, it proves that the 'evaluation' dimension is the common denominator in all groups while 'power' dimension toward Japanese and 'activity' dimensions toward Chinese and West Asians influence social distance. All foreigners excluding Americans receive closer social distance when having higher education level. Moreover, American women and older North Korean defectors receive closer social distance.

• Convergence Security Journal
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• v.11 no.2
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• pp.35-43
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• 2011

In the universities of U.S.A., Criminal Justice is the interdisciplinary study of the institutions and policies that constitute the criminal justice system, as well as theories of human behavior and philosophies of justice related to the maintenance of social order, the control of crime, and the achievement of a just society. There are 103 American Universities have Criminal Justice department and they provide about 180 differents courses as a pre-requisition or optional subject in the major. The most 10 courses that those colleges adopted are Introduction to Criminal Justice, Criminal Law, Criminology, Criminal Procedures, Research Methods in Criminal Justice, Criminal Investigation, Juvenile Justice, Terrorism, Ethical Issues in Criminal Justice, Introduction to Psychology or Introduction to Sociology. Also, 10 fields more important in the major if we group together similar courses those are Criminal Justice and Procedures Sequences, Law, Justice and corrections, Theory and Methods Sequences, Homelend Security and Security Operations, Forensics and Cybercrime, Management and Administration, Police, Race and Ethnicity, General Requirements, Other Social Science Fields. The combined degree program leading to Bachelor of Arts Degree in Criminal Justice and Master in Public Administration provides a concentration in criminal justice, management, administration, and leadership. They have big different courses between USA and Korea event though they have similar educative goal and way of approach to the target in the major.