• 충청수학회지
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• 제16권1호
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• pp.113-121
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• 2003

This paper is concerned with some properties of stable domains and limit functions. Using the relationship between cycles of periodic stable domains and orbits of critical points and using the Sullivan theorem [19], we prove that the value of a constant limit function in some stable domain for a rational function f of degree at least two lies in the closure of the set of critical orbits of f.

• Journal of Mechanical Science and Technology
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• 제18권4호
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• pp.606-621
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• 2004

A dynamic analysis using a hybrid finite element method was performed to characterize the effects of a number of manufacturing errors on bearing forces and critical tooth stress in the elements of a planetary gear system. Some tolerance control guidelines for managing bearing forces and critical stress are deduced from the results. The carrier indexing error for the planet assembly and planet runout error are the most critical factors in reducing the planet bearing force and maximizing load sharing, as well as in reducing the critical stress.

• 한국유체기계학회 논문집
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• 제14권6호
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• pp.91-95
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• 2011

This paper deals with the detail rotordynamic analysis for the assembly rotor composed of turbine wheel, turbine shaft, connecting arbor, and flange & spindle in order to perform the spin test of turbocharger turbine. Prior to rotordynamic analysis, the 1st spin test was performed but the test was failed by excess vibration in the neighborhood rated speed. It is the reason for this fail that the separation margin between the rated speed and critical speed is not enough, confirmed by rotordynamic analysis results. Since then, the dimension of turbine shaft was modified and the critical speeds were again reviewed for modified assmebly rotor. In results, the separation margin between the rated speed and critical speed is over 20% and then the 2nd spin test was performed successfully. In preparing spin test for turbine, compressor wheels and etc., the geometry design of connecting arbor and dimension of rough machining should be reviewed by considering rotordynamic results, and the separation margin should be enough for successful spin test.

• 산업경영시스템학회지
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• 제29권4호
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• pp.43-50
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• 2006

The objective of this research is to select the most effective technique from AMT (Advanced Manufacturing Technologies) and IMP (Innovative Management Practices) for improving manufacturing performance in shipbuilding enterprises. The research consists of several principal steps. The first step is to design critical criteria in evaluating manufacturing performance in shipbuilding enterprises. The second step is to develop sub-criteria of the critical criteria. The third step is to develop a four level AHP (Analytic Hierarchy Process) structure using the critical criteria, sub-criteria and techniques from AMT and IMP. The fourth step is to develope the pairwise comparison matrix by each level of AHP structure, which was based on survey data collected at the H heavy industry. And the last step is to select the most effective technique from AMT and IMP by using AHP analysis. The results of AHP analysis did not show clear difference in priority between techniques of AMT and IMP in terms of manufacturing performance of the shipbuilding enterprise. Thus, each critical criterion was assigned modified weights and examined the priority change of techniques by conducting performance sensitivity analysis.

• 드라이브 ㆍ 컨트롤
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• 제19권4호
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• pp.1-9
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• 2022

The structure and operating principle of the 2-speed shift reducer were explained, the allowable bending stress value of the material was compared with the analysis result through FM structural analysis program, and the average stress distribution value of von Mises was performed on the gear root atmosphere. The structural safety of the 2-speed planetary gear reducer was verified through FM structural analysis. The natural frequency was calculated by applying the specifications of the planetary gears of the 2-speed gearbox, and the critical speed of resonance was calculated by calculating the natural frequency and the transmission error of the engaged gear pair. As a result of analyzing the critical speed, since it is formed higher than the actual operating speed range, it is considered safe because there is no resonance problem due to the suggested specifications of the planetary gears of the 2-speed shift reduction.

• 수산해양교육연구
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• 제19권2호
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• pp.206-218
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• 2007

The purpose of this study was to investigate effects of critical thinking dispositions on vocational personalities in university students. Subjects were 111 University students in Busan. The questionnaire used in this research were Holland's Vocational Personality Questionnaire and California Critical Thinking Disposition Inventory. The results were analyzed by correlation analysis and enter multiple regression using the SPSS statistical package (SPSS for windows 12.0; SPSS Inc., Chicago, IL, USA). The study results were as follow: First, the students had much more S and R vocational personality characteristics than the others in vocational personality characteristics and had higher inquisitiveness and self-confidence scores than the others in critical thinking dispositions. Second, there were significant relationships between vocational personality types and critical thinking dispositions. Third, some of the vocational personality types were affected by the critical thinking dispositions. Especially I, E, and C personality of vocational personalities were prospected by critical thinking dispositions. Therefore, It's necessary that we understand the relationships between vocational personality types and critical thinking dispositions. Also we have to think over how to development career programs for university students to match to the learner's vocational personality type and critical thinking dispositions.

• Nuclear Engineering and Technology
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• 제54권3호
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• pp.834-841
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• 2022

System thermal-hydraulic (STH) code is adopted for nuclear safety analysis. The critical flow model (CFM) is significant for the accuracy of STH simulation. To overcome the defects of current CFMs (low precision or long calculation time), a CFM based on a genetic neural network (GNN) has been developed in this work. To build a powerful model, besides the critical mass flux, the critical pressure and critical quality were also considered in this model, which was seldom considered before. Comparing with the traditional homogeneous equilibrium model (HEM) and the Moody model, the GNN model can predict the critical mass flux with a higher accuracy (approximately 80% of results are within the ±20% error limit); comparing with the Leung model and the Shannak model for critical pressure prediction, the GNN model achieved the best results (more than 80% prediction results within the ±20% error limit). For the critical quality, similar precision is achieved. The GNN-based CFM in this work is meaningful for the STH code CFM development.

• 한국응급구조학회지
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• 제12권3호
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• pp.115-127
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• 2008

Purpose : This study aimed to examine the effects of empowerment of the paramedics on critical thinking and provide the basic materials for the qualitative improvement of emergency medical service. Methods : This study collected data with the paramedics working at general hospital and hospital emergency room in G metropolitan city, B metropolitan city, U metropolitan city, D metropolitan city and J province from July 1 to 31, 2008. Total 180 questionnaires were collected and 152 were used for final analysis, and the following results were obtained through statistical analysis using SPSS 12.0 program. Results : 1) Average score of empowerment was 4.44 out of 6 and according to average score by areas, significance was 4.94, capacity 4.92, self-determination 4.28, and effective-ness 3.62. 2) Empowerment by general characteristics was statistically significant in age (F = 3.313, p < 0.05), the final scholastic attainments(F = 2.436, p < 0.05), and salary(F = 1.695, p < 0.01). 3) Average score of critical thinking was 3.12 out of 7 and according to scores by areas, maturity was highest as 3.71, followed by no prejudice as 3.70, systemicity as 3.14, pursuit of truth as 3.05, much curiosity as 2.93, critical thinking and self-confidence as 2.92, and analysis as 2.91. 4) Critical thinking by general characteristics was statistically significant in marital status (F = 15.695, p < 0.01) and the final scholastic attainments (F = 2.606, p < 0.05). 5) Correlations between empowerment and critical thinking showed positive correlations as Pearson's correlation coefficient r = 0.400 and positive correlation in all areas including empowerment and critical thinking were found (r = 0.116-0.710). 6) The effect of empowerment on critical thinking was statistically significant in p < 0.01 and was explained as $R^2=0.155$. In the effects of empowerment on critical thinking, significance, capacity and self-determination were statistically significant in p < 0.01, effectiveness in p < 0.05 and were explained as R2 = 0.244. Conclusion : From the above results, it was found that empowerment had the influence on critical thinking, so it was considered that hospital managers and emergency room chiefs must develop and operate education and training program based on the concept of empowerment, maintenance and management strategies.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1999년도 봄 학술발표회 논문집
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• pp.331-338
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• 1999

In the present study, a searching technique for critical slip surface in two dimensional slope stability analysis is proposed. The failure surface generation and analysis has been usually limited to simple geometric shapes. However, more random surfaces need to be examined for some particular ground conditions. For this purpose, random searching technique is developed using genetic algorithm. The generalized limit equilibrium method is employed as the method of stability analysis. Using this technique, the factor of safety is compared with the result by using simplified Bishop's method. In addition, the convergent trend of fitness value is analyzed.

• 대한간호학회지
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• 제24권4호
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• pp.616-622
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• 1994

Precise concept analysis has been neglected be-cause of a lack of understanding of its necessity and a lack of conceptual analytic knowledge. Concept analysis is the mental work of examining parts, phenomenon and the interrelated whole of a thing. Focus in this article is to extract the critical attributes of hardiness and make an operational delinition. The process of concept analysis is illustrated and documented using the analytic approach described by Walker and Avant (1983). To explore the explicit or implicit meanings of hardiness, existing literature was reviewed. The evolution of hardiness and the dictionary definitions were also added. Hardiness can be defined as follows : A condition of being inured to fatigue or hardship which has three subcomponents-challenge, control and commitment. Critical attributes of hardiness were extracted that may be used in naming the occurrence of the phenomenon. Model case, contrary case, borderline case and related case were described. Antecedents and consequences were explored. The defining critical attributes of hardiness are : 1. Resistance-hardiness involves resistance of stress or hardship. 2. Hardiness involves appraisal of change as a chance. 3. Hardiness implies interpretation of events and self as influential,. 4. Hardiness requires active involving reaction Implications for nursing and for further study are added.