• Journal of Periodontal and Implant Science
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• 제53권5호
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• pp.362-375
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• 2023

Purpose: The aim of this study was to investigate the relationships between gingival thickness (GT) and keratinized gingiva width (KGW), papilla height (PH), and crown ratio (CR) by employing transgingival probing and an intraoral scanner (IOS). Methods: This cross-sectional study examined 360 maxillary anterior teeth from 60 patients. GT was assessed using transgingival probing with an endodontic spreader. KGW, CR, and PH were measured using an IOS. One-way analysis of variance, the Student's t-test, and Spearman correlation coefficients were employed for statistical analysis. Results: Higher GT was significantly associated with thinner KGW in the central region (P=0.019). There was no statistically significant difference in GT between teeth (P=0.06). PH was lower in lateral teeth than in canines (P=0.047), with a PH of 2.99 mm in lateral teeth. The KGW was narrower in canines than in central teeth (P=0.007). A moderate correlation was observed between KGW and PH in the central region (P=0.01), while a weak negative correlation was found between KGW and CR (P=0.043). Conclusions: A moderate negative correlation was found between GT and KGW, as well as between PH and KGW in central teeth. In contrast, a weak negative correlation existed between CR and KGW. The PH (2.99 mm) was lower in lateral teeth than in canines. The traditional paradigm, which suggests a positive correlation between KGW and GT, was reevaluated by measuring KGW using an IOS.

• 시큐리티연구
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• 제50호
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• pp.119-141
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• 2017

본 연구는 보안관련 종사자를 중심으로 조직몰입과 직무만족에 관한 종단적 인과관계를 분석하는데 그 목적이 있다. 이를 위해 한국노동패널 자료에서 경비, 경호, 보안서비스, 경찰, 교도관 종사자를 분류한 뒤 자기회귀교차지연 분석을 적용하였다. 자료분석은 SPSS 18.0과 AMOS 20.0을 이용하였으며, 가설 검정 전에 타당도 검증과 신뢰도 분석을 실시하였다. 분석결과를 요약하면 t-1 시점의 조직몰입이 t 시점의 조직몰입에 정(+)적인 영향을 미치며, t-1 시점의 직무만족이 t 시점의 직무만족에 정(+)적인 영향을 미치는 것으로 나타났다. 조직몰입이 직무만족에 영향을 미치는 교차회귀계수가 유의한 것으로 나타났으며(1차년 조직몰입 ${\rightarrow}$ 2차년 직무만족, 2차년 조직몰입 ${\rightarrow}$ 3차년 직무만족), 직무만족이 조직몰입에 영향을 미치는 교차회귀계수 역시 유의한 것으로 나타났다(2차년 직무만족 ${\rightarrow}$ 3차년 조직몰입). 교차회귀계수를 종합해 봤을 때 조직몰입이 직무만족에 선행하며, 예측변인으로 작용한다고 해석할 수 있다. 이상의 연구결과는 조직몰입과 직무만족의 선후 관계를 살펴보았다는 점에서 그 의미가 있다.

• 대한기계학회논문집
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• 제8권5호
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• pp.442-449
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• 1984

본 연구에서는 두 분류가 교우되어 배합이 이루어지는 유동역에서 3차원 방향 에 대하여 평균속도분포, 난류강도분포, 난류전단응력분포, 상관계수의 분포 및 난류 운동에너지와 운동량의 변화 등을 측정 분석하였다.

• 대한기계학회논문집B
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• 제25권11호
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• pp.1640-1649
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• 2001

The present study investigates the effects of various rib arrangements on heat/mass transfer in the cooling passage of gas turbine blades. A complex flow structure occurs in the cooling passage with rib turbulators which promote heat transfer on the wall. It is important to increase not only the heat transfer rates but also the uniformity of heat transfer in the cooling passage. A numerical computation is performed using a commercial code to calculate the flow structures and experiments are conducted to measure heat/mass transfer coefficients using a naphthalene sublimation technique. A square channel (50 mm $\times$ 50 mm) with rectangular ribs (4 mm $\times$ 5 mm) is used fur the stationary duct test. The experiments focus on the effects of rib arrangements and gap positions in the discrete ribs on the heat/mass transfer on the duct wall. The rib angle of attack is 60°and the rib-to-rib pitch is 32 mm, that is 8 times of the rib height. With the inclined rib angle of attack (60°), the parallel rib arrangements make a pair of counter rotating secondary flows in the cross section, but the cross rib arrangements make a single large secondary flow including a small secondary vortex. These secondary flow patterns affect significantly the heat/mass transfer on the ribbed wall. The heat/mass transfer in the parallel arrangements is 1.5 ∼2 times higher than that in the cross arrangements. However, the shifted rib arrangements change little the heat/mass transfer from the inline rib arrangements. The gap position in the discrete rib affects significantly the heat/mass transfer because a strong flow acceleration occurs locally through the gap.

• Structural Engineering and Mechanics
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• 제42권5호
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• pp.715-728
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• 2012

This paper deals with determining the fundamental frequency of tall buildings that consist of framed tube, shear core, belt truss and outrigger systems in which the framed tube and shear core vary in size along the height of the structure. The effect of belt truss and outrigger system is modeled as a concentrated rotational linear spring at the belt truss and outrigger system location. Many cantilevered tall structures can be treated as cantilevered beams with variable cross-section in free vibration analysis. In this paper, the continuous approach, in which a tall building is replaced by an idealized cantilever continuum representing the structural characteristics, is employed and by using energy method and Hamilton's variational principle, the governing equation for free vibration of tall building with variable distributed mass and stiffness is obtained. The general solution of governing equation is obtained by making appropriate selection for mass and stiffness distribution functions. By applying the separation of variables method for time and space, the governing partial differential equation of motion is reduced to an ordinary differential equation with variable coefficients with the assumption that the transverse displacement is harmonic. A power-series solution representing the mode shape function of tall building is used. Applying boundary conditions yields the boundary value problem; the frequency equation is established and solved through a numerical process to determine the natural frequencies. Computer program has been developed in Matlab (R2009b, Version 7.9.0.529, Mathworks Inc., California, USA). A numerical example has been solved to demonstrate the reliability of this method. The results of the proposed mathematical model give a good understanding of the structure's dynamic characteristics; it is easy to use, yet reasonably accurate and suitable for quick evaluations during the preliminary design stages.

• The Korean journal of internal medicine
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• 제33권6호
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• pp.1119-1128
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• 2018

Background/Aims: In multicenter clinical trials, laboratory tests are performed in the laboratory of each center, mostly using different measuring methodologies. The purpose of this study was to evaluate coefficients of variation (CVs) of laboratory results produced by various measuring methods and to determine whether mathematical data adjustment could achieve harmonization between the methods. Methods: We chose 10 clinical laboratories, including Green Cross Laboratories (GC Labs), the central laboratory, for the measurement of total cholesterol, high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), serum triglycerides, creatinine, and glucose. The serum panels made with patient samples referred to GC Labs were sent to the other laboratories. Twenty serum samples for each analyte were prepared, sent frozen, and analyzed by each participating laboratory. Results: All methods used by participating laboratories for the six analytes had traceability by reference materials and methods. When the results from the nine laboratories were compared with those from GC Labs, the mean CVs for total cholesterol, HDL-C, LDL-C, and glucose analyzed using the same method were 1.7%, 3.7%, 4.3%, and 1.7%, respectively; and those for triglycerides and creatinine analyzed using two different methods were 4.5% and 4.48%, respectively. After adjusting data using Deming regression, the mean CV were 0.7%, 1.4%, 1.8%, 1.4%, 1.6%, and 0.8% for total cholesterol, HDL-C, LDL-C, triglyceride, creatinine, and glucose, respectively. Conclusions: We found that more comparable results can be produced by laboratory data harmonization using commutable samples. Therefore, harmonization efforts should be undertaken in multicenter trials for accurate data analysis (CRIS number; KCT0001235).

• Wind and Structures
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• 제27권6호
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• pp.381-397
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• 2018

Nonlinear behavior in fluid-structure interaction (FSI) of bridge decks becomes increasingly significant for modern bridges with increasing spans, larger flexibility and new aerodynamic deck configurations. Better understanding of the nonlinear aeroelasticity of bridge decks and further development of reduced-order nonlinear models for the aeroelastic forces become necessary. In this paper, the amplitude-dependent and neutral angle dependent nonlinearities of the motion-induced loads are further highlighted by series of computational fluid dynamics (CFD) simulations. An effort has been made to investigate a semi-analytical time-domain model of the nonlinear motion induced loads on the deck, which enables nonlinear time domain simulations of the aeroelastic responses of the bridge deck. First, the computational schemes used here are validated through theoretically well-known cases. Then, static aerodynamic coefficients of the Great Belt East Bridge (GBEB) cross section are evaluated at various angles of attack, leading to the so-called nonlinear backbone curves. Flutter derivatives of the bridge are identified by CFD simulations using forced harmonic motion of the cross-section with various frequencies. By varying the amplitude of the forced motion, it is observed that the identified flutter derivatives are amplitude-dependent, especially for $A^*_2$ and $H^*_2$ parameters. Another nonlinear feature is observed from the change of hysteresis loop (between angle of attack and lift/moment) when the neutral angles of the cross-section are changed. Based on the CFD results, a semi-analytical time-domain model for describing the nonlinear motion-induced loads is proposed and calibrated. This model is based on accounting for the delay effect with respect to the nonlinear backbone curve and is established in the state-space form. Reasonable agreement between the results from the semi-analytical model and CFD demonstrates the potential application of the proposed model for nonlinear aeroelastic analysis of bridge decks.

• 한국경제지리학회지
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• 제24권4호
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• pp.400-410
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• 2021

본 연구는 2000년부터 2019년까지 우리나라 16개 광역시·도의 패널자료를 활용하여 확장된 STIRPAT 모형을 통해 이산화탄소 배출량 결정요인을 분석하였다. 패널 데이터의 횡단면 의존성과 계수 이질성을 검정한 후, 이들 특성을 반영한 MG, CCEMG, AMG 추정법을 통해 분석하였다. AMG 추정법을 통해 분석한 결과를 살펴보면, 소득, 인구, 에너지 집약도의 계수가 양(+)의 부호로 통계적으로 유의하게 나타났으나, 도시화는 통계적으로 유의하지 않는 것으로 나타났다. 우리나라 이산화탄소 배출량의 감소는 에너지 효율의 증가와 지속가능한 경제성장을 통해 이루어질 수 있다. 따라서 이산화탄소 감축기술의 적극적인 개발로 저탄소 사회를 구축하고, 이와 함께 기술혁신을 통해 장기적으로 생산성 향상을 유발하여 지속가능한 경제성장에 기여할 수 있는 정책수립이 필요하다.

• 임상간호연구
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• 제29권2호
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• pp.163-174
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• 2023

Purpose: To identify the effect of a new leadership type by confirming the effect of clinical nurses' grit and nursing work environment on nursing performance and retention intention with the mediating effect of compassionate rationalism leadership in the process. Methods: A proportional stratified sampling method was used with 45 tertiary general hospitals nationwide as the sampling unit. An online survey targeting nurses who have been working continuously for more than one year was conducted from October 14 to November 9, 2022. The final analysis included 1,256 questionnaires. The correlation between the participants' variables was analyzed using Pearson's correlation coefficients. The mediating effect was confirmed using a regression analysis, and bootstrapping. Results: The compassionate rationalism leadership had a mediating effect on the relationship between grit and nursing performance (F=203.21, p<.001), nursing work environment and nursing performance (F=109.48, p<.001), grit and retention intention (F=149.90, p<.001), and nursing work environment and retention intention (F=25.14, p<.001). Conclusion: The compassionate rationalism leadership of nursing managers had a positive effect on nursing performance and retention intention. Therefore, with the development and application of educational programs of compassionate rationalism leadership, it can be used to improve nursing performance and operate an efficient nursing organization.

• 한국산림과학회지
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• 제63권1호
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• pp.35-41
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• 1984

우리나라 남부(南部) 해안선(海岸線)을 따라 천연분포(天然分布)되어 있는 해송(Pinus thunbergii)에 대(對)하여 침엽형질상(針葉形質上)으로 본 지역간(地域間), 지역내(地域內)의 집단간(集團間), 집단내(集團內)의 개체간(個體間)에 변이(變異)를 분석(分析)하였던 바 그 결과(結果)는 다음과 같다. 거치밀도(鋸齒密度), 침엽체적(針葉體積)의 형질(形質)은 다른 형질(形質)보다 변이개체(變異係體)가 비교적(比較的) 높게 나타났고 각(各) 집단내(集團內)의 개체간(個體間)에 있어서 영광(靈光)의 침엽횡단면형상비(針葉橫斷面形狀比)를 제외(除外)하고는 집단(集團) 모두 개체간(個體間)에 1% 수준(水準)의 유의성(有意性)을 인정(認定)할 수 있었다. 지역내(地域內)의 집단간(集團間)에 있어서는 동안형지역(東岸型地域)의 경우, 거치밀도(鋸齒密度), 침엽횡단면적(針葉橫斷面積)은 5% 수준(水準), 침엽체적(針葉體積)은 1% 수준(水準)에서 유의성(有意性)을 인정(認定)할 수 있었다. 서안형지역(西岸型地域)의 집단간(集團間)에 있어서 침엽횡단면형상비(針葉橫斷面形狀比), 침엽종단면형상비(針葉縱斷面形狀比)는 1% 수준(水準)의 유의성(有意性)이 있었고 남해안형지역(南海岸型地域)에서는 침엽체적(針葉體積)에서만 5% 수준(水準)에서 유의성(有意性)이 있었다. 지역간(地域問)에 있어서 침엽횡단면형상비(針葉橫斷面形狀比), 침엽횡단면적(針葉橫斷面積)은 5% 수준(水準)에서 유의성(有意性)을 인정(認定)할 수 있었으며 이들 형질(形質)은 동안형지역(東岸型地域)이 다른 지역(地域)과 유의차(有意差)가 있었다. 이상(以上)의 결과(結果)에서 우리나라 남부(南部) 해안(悔岸)에 분포(分布)되고 있는 해송은 침엽일부(針葉一部)의 형질(形質)에서 지역적(地域的)으로 분화(分化)가 이루워지고 있음을 알 수 있었다.