• 대한기계학회논문집B
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• 제29권1호
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• pp.16-26
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• 2005

Air-cooled heat sinks are employed in many electronic cooling applications since they provide significant heat transfer enhancement and operational flexibility. Strip-shaped fin heat sink is of interest and needs to be investigated as general cooling products for more applicability. The purposes of this study are to evaluate heat sink performance without bypass flow condition and to determine optimal heat sink geometries. The results show that the decreasing rate of thermal resistance of a heat sink decreases with increasing inlet air velocity, and the increasing rate of pressure drop increases with increasing inlet air velocity, but is not affected by input power. The increasing rate of optimal longitudinal fin spacing is larger than that of transverse fin spacing. The strip fin heat sink tested in this study showed better cooling performance compared to that of other plate fin type.matism. 2004; 50(11): 3504-3515.

• The Journal of Korean Physical Therapy
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• 제2권1호
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• pp.103-112
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• 1990

The intervertebral disc in the anterior portion of the function unit gives the spine its flexibility. The disc is attached closely to the vertebral endplates. Between these endplates and the annulus fibrosus, the nucleus pulposus of the lumbar disc is enclosed in a circle of unyielding tissues. Compressive pressure placed on the disc is dissipated circumferentially in a passive manner In response to the greater axial forced exerted on the lumbar spine in comparison to the cervical and thoracic spines, the nucleus pulposus has its greatest surface area in the lumbar spine. The intervertebral disc is not only structure that helps diss pate stresses placed on the spine. With flexion, extension, rotation, or shear stress, the load distribution on the function unit is shared by the intervertebral disc, anterior and posterior longitudinal ligaments, the facet joints and capsules, and other ligamentous structures like the ligamentum flavum, interspinous and supraspinous ligaments, which attach to the posterior elements of the functional unit.

• 기본간호학회지
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• 제3권1호
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• pp.108-127
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• 1996

The purpose of this research was to determine whether or not a education program of low back pain would have benificial effect on nurses. Nonequivalent control group pre-post test research was designed. Subjects for this study were 50 selected from nurses who work at a general hospital in Taegu. Of them, twenty seven were assigned to experimental group, twenty-three to control group. The data were collected during the period from June 27 to August 31, 1994. The instruments used in this study were Visual Analog Scale for low back pain, Sit-and-reach test for trunk flexibility, and 1 min sit up test for abdominal muscle endurance. Data related to general chracteristics and factors of low back pain were collected with questionnaire developed by this reseacher. The data were analyzed by $X^2-test$, t-test and paired t-test, using the SAS package program. The results of this study are summerized as follows : 1. The numbers of the experimental group with low back pain were not a statistically significant difference from pre to posttesting($X^2=0.77$, p=.379), and the numbers of the control group with low back pain were also not a statistically significant difference from pre to posttesting($X^2=0.09$, p=.767). 2. The severity of low back pain of the experimental group was not a statistically significant difference from pre to posttesting(t=-0.55, p=.5857), and the severity of low back pain of the control group was also not a statistically significant difference from pre to posttesting(t=-0.70, p=.3101). 3. The trunk flexibility of the experimental group was not a statistically significant difference from pre to posttesting(t= 1.08, p=.2835), and the control group's trunk flexibility was also not a statistically significant difference from pre to posttesting(t=0.85, p=.4026). 4. The abdominal muscle endurance of the experimental group was a statistically significant difference from pre to posttesting(t=-2.42, p=.0190), but the control group's abdominal muscle endurance was not a statistically significant difference from pre to posttesting(t=-0.06, p=.9556) This study suggest that replication of study with more sample and more rigid treatment should be needed. And furthermore, the longitudinal research is needed to determine the effectiveness of education program.

• 한국노년학
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• 제37권4호
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• pp.871-891
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• 2017

한국의 중 고령자들이 60세 이전에 조기은퇴하는 현상의 주된 이유로 건강문제가 거론된다. 일부 선행연구에서는 은퇴 이후 시점에서의 건강과 조기은퇴 간의 관계를 알아보았다는 점에서 역인과관계 문제가 존재한다. 또한 근로 당시의 건강상태를 고려하지 않고 건강문제와 조기은퇴 간의 관계를 분석함으로 인해 건강문제의 영향력이 과대평가될 수 있는 문제점이 제기된다. 이를 보완하기 위하여 본 연구는 근로 시기와 비교해 건강상태의 악화가 조기은퇴에 어떠한 영향을 미치는지 알아보는 것을 목적으로 하였다. 고령화패널 1차 자료에서 조사된 45~52세 중 고령 근로자 1,049명을 대상으로 고령화패널 5차 자료까지의 추적연구를 통해 건강의 악화가 조기은퇴에 미치는 영향을 콕스의 비례위험모형으로 분석하였다. 그 결과 은퇴 이전 시점에서 치료가 필요한 만성질환의 증가는 자영업자의 은퇴 위험을, 주관적 건강상태의 악화는 임금근로자의 은퇴 위험을 유의하게 높이는 것을 확인했다. 이러한 결과는 역인과관계 문제와 편향 문제를 없애거나 줄인 상황에서도 건강 악화는 여전히 조기은퇴의 주된 원인임을 보여준다. 자영업자와 임금근로자 간 은퇴원인의 차이는, 자영업자의 근로신축성에 기인한 것으로 추측된다.

• 응용통계연구
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• 제33권1호
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• pp.47-59
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• 2020

본 논문에서는 마코프 이항 회귀 모형의 시차가 알려져 있거나 그렇지 않은 경우일 때, t-링크 함수를 갖는 종단적 마코프 이항 회귀 모형을 제시한다. 일반적으로, 이항 회귀 모형에서는 로직 모형이나 프로빗 모형이 주로 사용된다. t-링크 함수는 t 분포가 자유도가 커질수록 정규분포로 근사하기 때문에 프로빗 모형을 대신 더 많은 유연성을 위해 사용될 수 있다. 게다가 마코프 회귀모형은 종단 자료에 대해 사용될 수 있다. 우리는 마코프 회귀 모형의 시차를 결정하기 위해 베이지안 방법을 제시하고자 한다. 특히, 각 모델의 차수에 대해 알고 있는 경우에는 DIC를 기준으로 모델 비교를 실시하였다. 모델의 차수에 대해 모르는 경우에는 가능한 모델들의 사후 확률을 이용하였다. 복잡한 베이지안 계산을 해결하기 위하여 Albert와 Chib (1993), Kuo와 Mallick (1998)과 Erkanli 등 (2001)의 방법을 이용하여 모델을 재설정하였다. 제안하는 방법은 시뮬레이션 데이터와 Somer 등 (1984)에 의해 조사된 인도네시아 어린이 종단 데이터에 적용했다. 마코프 이항 회귀모형의 순서에 대해서 아는 경우와 모르는 경우를 각각 가정하여 최적의 모델을 알아보기 위해 MCMC 방법을 사용하였다. 또한, 매트로폴리스 해스팅 알고리즘의 수렴성을 점검하기 위해 Gelman과 Rubin의 진단을 이용했다.

• 한국해양공학회지
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• 제21권4호
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• pp.38-44
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• 2007

The structural response characteristics of Tension leg platforms(TLPs) in waves are examined for presenting the basic data for structural design of TLPs. The numerical approach is based on a combination of the three dimensional source distribution method and the structural response analysis method, in which the superstructure of TLP is assumed to be flexible instead of rigid. Hydrodynamic and hydrostatic forces on the submerged surface of a TLP have been accurately calculated by excluding the assumption of the slender body theory. The hydrodynamic interactions among TLP members, such as columns and pontoons, and the structural damping are included in structural analysis. The mooring forces are estimated as the sum of pretension of tendons and variational tension due to longitudinal displacements. Stiffness matrices of elastic beam elements connecting nodes are formulated by ordinary method of three dimensional frame analysis. The equation of motion about the whole structure is obtained by the sum of forces and moments acting on each nodes.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1997년도 추계학술대회
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• pp.343-346
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• 1997

A new type of stent was invented using a Nitinol wire. The hoop strength of the new stent was found to be 2 times larger than that of the Cragg or Memotherm stents. However, the longitudinal flexibility of the new stent was inferior to both the Cragg and Memotherm stents. This new stent seems to be useful or the treatment of stenosis with straight configuration, but need to be improved or use in tortuous stenotic region. The stent was applied to the patients with esophargeal stenosis and showed a good result.

• 소성∙가공
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• 제17권1호
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• pp.27-34
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• 2008

In order to manufacture a doubly curved sheet metal, the incremental roll forming process which adopts advantages such as the flexibility of the incremental forming process and continuous bending deformation of the roll forming process has been experimentally investigated. An experimental equipment was developed which was named as unit roll set (URS) consisting of two pairs of support rolls and an upper center roll. The upper roll equipped with the servo control unit is motor-driven and can be positioned in the vertical direction according to the user's commands. Four support rolls are idle, and they freely rotate only along the axis so as to transfer the plate more stably in the tangential direction of the rotation of the driving roll. In the process, the plate is deformed incrementally as deformation proceeds simultaneously in longitudinal and transverse directions. Through the experiments using URS, information regarding to forming schedules is found out to fabricate curved hull plates. This study demonstrates the further application of the incremental roll forming process in shipbuilding industries.

• Journal of Yeungnam Medical Science
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• 제36권3호
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• pp.183-191
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• 2019

Some patients with type 1 and type 2 diabetes mellitus (DM) present with cognitive dysfunctions. The pathophysiology underlying this complication is not well understood. Type 1 DM has been associated with a decrease in the speed of information processing, psychomotor efficiency, attention, mental flexibility, and visual perception. Longitudinal epidemiological studies of type 1 DM have indicated that chronic hyperglycemia and microvascular disease, rather than repeated severe hypoglycemia, are associated with the pathogenesis of DM-related cognitive dysfunction. However, severe hypoglycemic episodes may contribute to cognitive dysfunction in high-risk patients with DM. Type 2 DM has been associated with memory deficits, decreased psychomotor speed, and reduced frontal lobe/executive function. In type 2 DM, chronic hyperglycemia, long duration of DM, presence of vascular risk factors (e.g., hypertension and obesity), and microvascular and macrovascular complications are associated with the increased risk of developing cognitive dysfunction. The pathophysiology of cognitive dysfunction in individuals with DM include the following: (1) role of hyperglycemia, (2) role of vascular disease, (3) role of hypoglycemia, and (4) role of insulin resistance and amyloid. Recently, some investigators have proposed that type 3 DM is correlated to sporadic Alzheimer's disease. The molecular and biochemical consequences of insulin and insulin-like growth factor resistance in the brain compromise neuronal survival, energy production, gene expression, plasticity, and white matter integrity. If patients claim that their performance is worsening or if they ask about the effects of DM on functioning, screening and assessment are recommended.

• 의학교육논단
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• 제25권2호
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• pp.119-125
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• 2023

Pusan National University School of Medicine (PNUSOM) began analyzing the cohort of pre-medical students admitted in 2015 and has been conducting purposeful analyses for the past 3 years. The aim of this paper is to introduce the process of cohort establishment, cohort composition, and the utilization of cohort analysis results. PNUSOM did not initially form a cohort with a purpose or through a systematic process, but was able to collect longitudinal data on students through the establishment of a Medical Education Information System and an organization that supports medical education. Cohort construction at our university is different in terms of a clear orientation toward research questions, flexibility in cohort composition, and subsequent guideline supplementation. We investigated the relevance of admission factors, performance improvements, satisfaction with the educational environment, and promotion and failure rate in undergraduate students, as well as performance levels and career paths in graduates. The results were presented to the Admissions Committee, Curriculum Committee, Learning Outcomes Committee, and Student Guidance Committee to be used as a basis for innovations and improvements in education. Since cohort studies require long-term efforts, it is necessary to ensure the efficiency of data collection for graduate cohorts, as well as the validity and ethics of the study.