• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집A
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• pp.298-303
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• 2001

The critical thickness of an epitaxial film on a substrate in electronic or optoelectronic devices is studied on the basis of equilibrium dislocation analysis. Two geometric models, a single dislocation and an array of dislocations in heteroepitaxial system, are considered respectively to calculate the misfit dislocation formation energy. The isotropic linearly elastic stress fields for the models are obtained by means of complex potential method combined with alternating technique, and are used for calculating the formation energies. As a result, the effect of elastic mismatch between film and substrate on critical thickness is presented and $Si_xGe_{1-x}/Si$ epitaxial structure is analyzed to predict the critical thickness with varying germanium concentration.

• 한국경영과학회지
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• 제29권1호
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• pp.1-16
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• 2004

Critical success factors (CSFs) have been replicated and applied in a wide variety of settings for more than two decades. Most previous research on CSF have focused on identifying critical factors, based on the variance theory, in terms of the correlation between individual factor and Information system (IS) success. However, it is unknown how a set of critical factors Influence each other and lead to IS success, which means the process of IS implementation. in this research, we aim to understand how a set of critical factors influence each other and lead to IS success in the context of IS implementation for Customer Relationship Management based on the process theory. This research has implications In explaining a mechanism leading to CRM systems success based on the influencial relationships among the critical factors.

• 성인간호학회지
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• 제19권3호
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• pp.495-507
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• 2007

Purpose: This critical ethnography was performed to explore the experiences of nurses who are working with patients in an industrial disaster hospital. During the research process, I focused on the experiences of conflict in caring patients. Methods: Data for the study came from 13 informants with their corresponding patients through interview and observation from March 2002 to February 2004. The data was examined line by line; then compared and contrasted based on a critical discourse analysis. Results: Nurses' conflicts came from discrepancies of the world views from that of the patients. Such conflicts arose because of various issues as follows: Worker as an individual vs patients, nurse as young women vs the medical profession, hospital as an extended home vs health care setting, and hospitalization as a means to enhance work capacity vs a means of treatment. Conclusion: We need more study on the development of adaptive strategy for the nurses to overcome conflicts during their nursing career. Developing a nurses' and patient role intervention program is needed.

• 한국안전학회지
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• 제35권2호
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• pp.94-99
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• 2020

Bikers can be subjected to injuries from unexpected accidents even if they wear basic helmets. A properly designed airbag can efficiently protect the critical areas of the human body. This study introduces a wearable smart airbag system using machine learning techniques to protect human neck and shoulders. When a bicycle accident happens, a microprocessor analyzes the biker's motion data to recognize if it is a critical accident by comparing with accident classification models. These models are trained by a variety of possible accidents through machine learning techniques, like k-means and SVM methods. When the microprocessor decides it is a critical accident, it issues an actuation signal for the gas inflater to inflate the airbag. A protype of the wearable smart airbag with the machine learning techniques is developed and its performance is tested using a human dummy mounted on a moving cart.

• 문화기술의 융합
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• 제2권2호
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• pp.9-15
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• 2016

Objectives : The purpose of this study to investigate the Critical Thinking disposition in Nursing College students and related to ability of basic nursing science. Methods : Data were collected from 36 students who were students belong to one of province University. The instrument used in this study was California Critical Thinking Disposition Inventory(CCTDI) by Facione & Facione. The instrument was composed of 7 sub-items, truth-seeking, analyticity, systematicity, open-mindness, critical thinking, self-confidence, inquisitiveness, and maturity. The data were analyzed by descriptive statistics, t-test, ANOVA, Pearson Correlations with SPSS 12.0. Results : The result of this study were as follow; The average of total score in critical thinking disposition was 44.8, which means middle level(below 40: low, above 50: high level). Maturity was the highest while open-mindness was the lowest with an average score 5.01. There was significant difference between critical thinking and basic nursing science grade while there was no difference between age, gender, and religion. There was strongly relation between critical thinking disposition and basic nursing science(F=2.84, p=.01). Conclusion : According to the results of this study, nursing curriculum should be considered critical thinking disposition.

• 한국항공운항학회지
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• 제21권4호
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• pp.47-52
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• 2013

In this paper, limit cycle flutter induced by Hopf bifurcation is studied with nonlinear system analysis approach and observed for the critical slowing down phenomenon. Considering an attractor of the dynamics of a system, when a small perturbation is applied to the system, the dynamics converge toward the attractor at some rate. The critical slowing down means that this recovery rate approaches zero as a parameter of the system varies and the size of the basin of attraction shrinks to nil. Consequently, in the pre-bifurcation regime, the recovery rates decrease as the system approaches the bifurcation. This phenomenon is one of the features used to forecast bifurcation before they actually occur. Therefore, studying the critical slowing down for limit cycle flutter behavior would have potential applicability for forecasting those types of flutter. Herein, modeling and nonlinear system analysis of the 2D airfoil with torsional nonlinearity have been discussed, followed by observation of the critical slowing down phenomenon.

• Korean Journal of Mathematics
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• 제17권4호
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• pp.419-428
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• 2009

We show the existence of at least one nontrivial solution of the homogeneous mixed type nonlinear elliptic problem. Here mixed type nonlinearity means that the nonlinear part contain the jumping nonlinearity and the critical growth nonlinearity. We first investigate the sub-level sets of the corresponding functional in the Soboles space and the linking inequalities of the functional on the sub-level sets. We next investigate that the functional I satisfies the mountain pass geometry in the critical point theory. We obtain the result by the mountain pass method, the critical point theory and variational method.

• 한국철도학회논문집
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• 제4권3호
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• pp.116-122
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• 2001

As freight traffic becomes heavier, the high speed of existing freight cars is essential, instead of the construction of a new railway. The high speed can be achieved by the modifications of freight bogie design. In this paper, an analytical model of freight bogie is developed to decide the critical speed. The dynamic responses of the analytical model are compared with the experimental data from a running test of freight bogie and showed good agreements between them. The analytical model is used to find the design of freight bogie. The parameter studies show that the reduction of wheelset mass ratio and the increase of the axle distance of freight bogie can increase the critical speed, but the primary lateral stiffness has little effects on the critical speed. And this study also shows that smaller wheel conicity deteriorates the running safety of freight car, which means that the overhauling of the wheel of freight bogie should be done regularly.

• 한국정밀공학회지
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• 제21권11호
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• pp.179-185
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• 2004

The effect of viscous damping on stability of beam resting on an elastic foundation subjected to a dry friction force is analytically studied. The beam resting on an elastic foundation subjected to dry friction force is modeled for simplicity into a beam resting on Kelvin-Voigt type foundation subjected to distributed follower load. In particular, the effects of four boundary conditions (clamped-free, clamped-pinned, pinned-pinned, clamped-clamped) on the system stability are considered. The critical value and instability type of columns on the elastic foundation subjected to a distributed follower load is investigated by means of finite element method for four boundary conditions. The elastic foundation modulus, viscous damping coefficient and boundary conditions affect greatly both the instability type and critical load. Also, the increase of damping coefficient raises the critical flutter load (stabilizing effect) but reduces the critical divergence load (destabilizing effect).

• 한국표면공학회지
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• 제32권3호
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• pp.410-415
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• 1999

The adhesion strength of sputtered copper films to Inconel substrates has been studied using the scratch test. The effects of substrate treatments before deposition such as chemical or ion bombardment etching were investigated by means of a mean critical load derived from a Weibull-like statistical analysis. It was found that the mean critical load was very weak unless the amorphous layer produced by mechanical polishing on the substrate surface was eliminated. Chemical etching in a nitric-hydrochloric acid bath was shown to have practically no effect on the enhancement of the adhesion. In contrast, the addition in this bath of nickel and copper sulphates allowed removal of the amorphous layer and an increase in the values of the mean critical load. However, it was observed that excessive chemical etching could cancel out the mean critical load enhancement. The results obtained in the case of ion bombardment etching pretreatments could be far higher than those obtained with chemical etching. Moreover, for a sufficiently long period of ion bombardment etching, the adhesion strength was so high that it was impossible to observe evidence of an adhesion failure.