• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2008년도 춘계학술대회논문집
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• pp.97-100
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• 2008

Various flyers in nature have attracted great interests with a recent need for developing versatile and small-size flight vehicles. In the present study, we focus on the flying fish which has been observed to glide a long distance just above a seawater surface. Since previous studies have depended on the field observation or measurement of the physical parameters only, quantitative data of the flying fish flight has not been provided so far. Therefore, we evaluate the wing performance of the flying fish in gliding flight by directly measuring the lift, drag and pitching moment on real flying fish models (Cypselurus hiraii) in a wind tunnel. In addition, we investigate the roles of wing morphology like the enlarged pectoral and pelvic fins, and lateral dihedral angle of pectoral fins. With both the pectoral and pelvic fins spread, the lift-to-drag ratio is larger and the longitudinal static stability is enhanced than those with the pelvic fins folded. From the glide polar, we find that the wing performance of flying fish is equivalent to those of medium-size birds like the petrel, hawk and wood duck. Finally, we examine the effect of water surface underneath the flying fish and find that the water surface reduces the drag and increases the lift-to-drag ratio.

• 한국생산제조학회지
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• 제20권6호
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• pp.773-777
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• 2011

Conventional ultrasonic thickness measurement is to be considered as the assumption that the ultrasonic velocity is known. In actual applications the velocity is often not well known and access is often limited to one side. This paper aims at determining the ultrasonic velocity and thickness of plates with parallel or wedged surfaces using contact measurements made on one surface only. For wedged plates the thickness at one point and the wedge angle are determined. Equations are used for determining the ultrasonic velocity, thickness and wedge angle of the plate based on the times-of-flight measured by two contact transducers coupled to one surface. The time-of-flight of the obliquely reflected longitudinal wave echo was measured as a function of the separation between the two transducers. In addition, a simulation was made for comparing the experimental data and a FEM image. Experiments and simulations were performed on flat and wedged plates of aluminium materials; the calculated results for the unknown quantities are generally agreed with them to some degree.

• 성인간호학회지
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• 제13권1호
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• pp.70-81
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• 2001

The relationships among self efficacy, depression and coping with cancer were examined in 194 outpatients who had received a diagnosis of cancer. The sample for this descriptive correlational study consisted of people who were at least 19 years old and had been treated for cancer at 6 hospital in Seoul. Data were collected using a self-report questionnaire. The results of this study are as follows: 1. People who attributed cancer to heredity/family showed the highest mean score of self efficacy. People who attributed cancer to smoking showed the highest mean score of depression. and coping. 2. There were significant differences between causal attribution and depression and between causal attribution and coping. 3. There was a negative correlation between self-efficacy and depression(r=-.301, p= .000), whereas there was a positive correlation between self-efficacy and coping (r=.195, 0=.006). Finally, it is evident that identifying clear perceived causes, self-efficacy, depression and coping in patients with cancer continues to challenge researchers. Based upon this study, it is recommended that future research have a longitudinal design that allows for the identification of changes in perception, emotion and coping and, possibly, different relationships over time.

• 노동경제논집
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• 제32권3호
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• pp.27-59
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• 2009

본고는 한국교육종단연구의 중학생 표본 및 교육행정 데이터의 학교 자료를 이용하여 사교육 수요에 영향을 주는 구체적인 학교 특성을 분석하였다. 분석 결과, 교사에 대한 개별 학생의 평가지수가 높고 교원의 평균 학력이 높을수록 사교육비 지출액이 적었고, 수준별로 운영되는 교과교실도 해당 과목의 사교육비 지출액을 줄이는 효과가 있었다. 이 결과는 정규 수업의 질을 높이기 위한 교원양성 방식의 개선과 학생 중심의 교원평가제 도입, 그리고 평준화의 단점을 보완하기 위한 수준별 수업의 운영 등이 사교육 경감에 도움이 될 수 있다는 것을 의미한다.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제36권4호
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• pp.135-139
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• 2014

Purpose: We review published research on temporomandibular joint (TMJ) total replacement that compares costochondral graft and customized total joint reconstruction (especially TMJ concepts), focusing on effectiveness. Methods: We searched PubMed databases, including prospective, retrospective, case-control or longitudinal studies and significant statistical analysis. In data analysis, we divided outcomes into 'Acceptable' or 'Non-acceptable'. Results: There were seven articles found dealing with costochondral graft and 180 patients. The majority of patients had satisfactory treatment outcomes (n=109, 61%). There were six articles including 275 patients using the alloplastic material TMJ concepts. Almost all patients had satisfactory treatment outcomes (n=261, 95%). Conclusion: Comparing customized total joint reconstruction with costochondral graft, use of TMJ concepts resulted in increased quality of life and fewer complications. In conclusion, we judged that alloplastic material such as TMJ concepts is more effective device in total joint replacement than costochondral graft.

• 대한간호학회지
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• 제37권3호
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• pp.324-333
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• 2007

Purpose: The purpose of this study was to develop and evaluate a quality of life scale for Korean patients with cancer (C-QOL). Methods: The C-QOL was developed and validated as follows, item generation, pilot study, and psychometric tests. A total of 337 patients diagnosed with stomach, liver, lung, colon, breast, or cervix cancer were recruited. The patients were asked to complete the preliminary questionnaire comprising the content-validated items, the SF-36, and the ECOG performance status. The obtained data was analyzed using descriptive statistics, factor analysis, multidimensional scaling (MDS), multitrait/multi-item matrix, ANOVA, t-test, and Cronbach's alpha. Results: Preliminarily twenty-six items were generated through content validity and a pilot study. Factor analysis and MDS extracted a total of 21 items with a 5-point Likert-type scale (C-QOL). The C-QOL included five subscales: physical status (6 items), emotional status (6 items), social function (3 items), concern status (2 items), and coping function (4 items). The C-QOL established content validity, construct validity, item convergent and discriminant validity, known-groups validity, reliability, and sensitivity. Conclusion: The Newly developed C-QOL is an easily applicable instrument which established psychometric properties and reflected Korean culture. It is recommended for further study to examine the responsiveness of the C-QOL using a longitudinal research design.

• 대한기계학회논문집A
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• 제24권7호
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• pp.1871-1877
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• 2000

Longitudinal and lateral forces acting at tire are known to be closely related to the tractive ability, braking characteristics, handling stability and maneuverability of ground vehicles. However, it is not feasible in the operating vehicles to measure the tire forces directly because of high cost of sensors, limitations in sensor technology, interference with the tire rotation and harsh environment. In this paper, in order to develop tire force monitoring system, a new vehicle dynamics monitoring model is proposed including the roll motion. Based on the monitoring model, tire force monitoring system is designed to estimate the lateral tire force acting at each tire. A newly proposed SKFMEC (Scaled Kalman Filter with Model Emr Compensator) method is developed utilizing the conventional EKF (Extended Kalman Filter) method. Tire force estimation performance of the SKFMEC method is evaluated in the Matlab simulations where true tire force data is generated from a 14 DOF vehicle model with a combined-slip Magic Formula tire model.

• 한국산학기술학회논문지
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• 제14권11호
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• pp.5434-5441
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• 2013

본 연구는 지배주주의 소유지배괴리도가 경영자 보수에 미치는 영향을 규명하기 위해 2001년부터 2008까지 공정위가 상호출자제한 기업집단으로 발표한 기업집단 소속 122개 기업 575건을 대상으로 실증분석을 시하였다. 실증분석 결과, 첫째, 지배주주의 소유지배괴리도와 경영자 보상 (등기임원 1인당 현금보상) 간에는 부(-)의 유의적인 관계가 존재하였다. 둘째, 지배주주의 소유지배괴리도는 경영성과와 경영자 보상 간의 민감도에 부(-)의 유의적인 영향을 미쳤다. 본 결과는 지배주주가 소유지분을 초과하여 지배권을 가질수록 지배주주의 대리인 비용에 대한 이해관계자의 우려를 완화시키기 위해 경영자 보상 수준을 낮추는 반면 경영성과에 대한 경영자 보상의 민감도를 약화시키는 것으로 나타났다.

• 노동경제논집
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• 제24권1호
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• pp.177-205
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• 2001

이 연구에서는 고연령층이 경험하는 은퇴과정의 다양성과 긴장 정도를 파악하고 있다. 은퇴 과정의 다양성을 규정 짓는 주요 요인으로서 중장년기의 종사상 지위에 초점을 둔다. 비정규직 종사자의 취업 불안정과 빈곤 위기는 취업시점에서뿐 아니라, 이후의 노동이동 과정과 고연령기 은퇴에 이르기까지 장기적으로 그 영향을 미칠 것으로 가정한다. 1998년과 1999년 한국노동 연구원에서 실시한 1~2차 한국노동패널 조사를 이용하여 중장년기에서 고연령기에 이르기까지의 노동이동 및 은퇴 과정을 유형화하고, 주요 유형별 소득수준을 비교하고 있다.

• 대한기계학회논문집B
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• 제30권10호
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• pp.966-972
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• 2006

A numerical simulation is performed fur developing turbulent flow in a strongly curved 180 deg pipe and its downstream tangent by a new solution code(PowerCFD) which adopts an unstructured cell-centered method. The governing equations are discretized as the full elliptic from of the equations of motion. Three typical two-equation turbulence models of low-Reynolds-number form are used to approximate the turbulent stress field. Solutions fur both streamwise and circumferential velocity components are compared with the experimental data by Azzola et at.(1986). The ${\kappa}-{\omega}$ model by Wilcox(1988) is found to give better prediction performance than the other two. Predicted secondary velocities and streamwise velocity component contours at sequential longitudinal stations are also presented in order to enable a detailed description of the complete flow. It is also found that, in the bend both mean streamwise and secondary velocities never achieve a fully-developed state and the code is capable of producing very well the complex nature of steady flow in a strongly curved pipe.