• 한국콘텐츠학회논문지
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• 제22권5호
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• pp.383-392
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• 2022

문화기술은 메타버스와 같이 타 산업과의 융·복합화를 통해 새로운 가치 창출에 기여하고 있다. 정부도 문화콘텐츠산업의 경쟁력 확보를 위해 해당 분야의 연구개발에 적극적으로 투자하고 있다. 이에 본 연구에서는 국가연구개발 과제 중 문화기술의 R&D 효율성을 과제 특성별로 비교 분석하였다. 이를 위해 2016-2019년에 수행된 968개 국가연구개발 과제를 대상으로 자료포락분석과 비모수 검정을 하였다. 분석 결과 기술 분류별로는 문화유산, 문화콘텐츠, 생활문화 순으로 R&D 효율성이 높았다. 연구수행 주체별로는 대학, 민간기업, 공공 연구기관 순으로 R&D 효율성이 높았다. 또한, 타 기관과 협력한 경우 협력하지 않은 경우보다 R&D 효율성이 낮았다. 지역별로는 서울 지역에서 수행된 과제가 타 지역의 과제보다 R&D 효율성이 높았다. 즉, 문화기술분야의 국가연구개발 과제 특성에 따라 R&D 효율성 차이가 존재함을 확인하였다. 이는 문화기술에 대한 국가연구개발 과제를 기획할 때 이러한 특성을 고려하여 전략적으로 추진해야 함을 시사한다.

• 디자인학연구
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• 제11권1호
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• pp.237-244
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• 1998

래피드 프로토 타이핑 기술은 일반적으로 제품의 사용 성(usability)을 미리 평가해 볼 수 있는 효과적 방법으로 여겨지고 있다. 그러나 아직까지 래피드 프로토 타이핑(rapid prototyping)에 의해 생성한 프로 타이프(prototype)를 가지고 사용 성 평가를 할 경우, 실제품으로 할 경우에 비교해 사용자 행위상에 어떤 차이가 있는 지에 대해서는 충분한 검증이 없었다. 본 연구의 목적은 래피드 프로토 타이핑에 의해 생성한 프로토 타이프가 실제품을 대신해 사용 성 평가에 사용될 수 있는 가를 검증하는 것이다. 이를 위해 우선 가전제품 중 사용자 인터페이스(user interface)가 비교적 단순한 냉장고의 제어 표시판(control-display)을 대상으로 한 실험을 수행하였다. 16명의 여자 피 실험 자 들이 피 실험 자간 실험(between-subjects)에 실험에 참여하여, 8명은 실제 냉장고의 제어 표시 판을 사용했고 나머지 8은 프로토 타이프를 사용했다. 각 그를 모두 냉장고 제어 표시 판의 대표적 기능인 시계조작, 절전냉장, 쾌속냉동 등 세 작업을 수행하도록 했다. 실제 품과 프로토 타이프의 차이는 작업 실패율, 작업완수 시간, 버튼 조작 회수 측면에서 분석되었다. 비 모수 검정(non-parametric)에 의한 분석 결과, 실제 품과 프로토 타이프 사이에 통계적 유의한 차이는 없는 것으로 나타났다. 이는 냉장고와 같이 비교적 단순한 제품의 사용 성 평가에는 래피드 프로토타이핑 기술의 효과적으로 사용될 수 있음을 보여준 결과라고 할 수 있다.

• 환경영향평가
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• 제28권2호
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• pp.83-100
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• 2019

본 연구는 팔당호 내 4개 지점을 대상으로 각 지점에서의 장기 수질 변화 및 지점 간 시차성을 확인하기 위하여 비모수적 추세분석 방법인 Seasonal Kendall test, LOWESS와 Cross Correlation을 수행하였다. 본 분석을 위하여 2004년 1월부터 2016년 12월까지, 각 지점별 9개 수질 항목(수온, EC, DO, BOD, COD, T-N, T-P, TOC, Chl-a)의 주별 분석 자료를 사용하였다. Seasonal Kendall test 결과 수온은 증가, EC와 T-N, T-P는 전 지점 모두 감소 경향을 나타내었다. LOWESS 결과 BOD 농도는 전 지점에서 2013년부터 2016년까지 "감소" 경향을 나타내었고 COD는 2012년부터 "증가" 경향을 나타내었다. 따라서 2012~2013년은 팔당호 전 지점에서 BOD의 개선과 함께 COD의 증가가 나타나는 전환기였음을 확인할 수 있었다. Cross Correlation 결과, 모두 시차성 없음으로 나타났다. 본 연구를 통하여 팔당호에 대한 보다 적합한 수질관리를 위하여 위의 전환기에 대한 발생원인 분석과 함께 수질 측정주기의 증가를 통한 보다 정밀한 모니터링이 필요할 것으로 판단된다.

• 지능정보연구
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• 제28권2호
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• pp.19-31
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• 2022

기계학습 모델 구축 간 트레이닝 데이터를 활용하며, 훈련 간 사용되지 않은 테스트 데이터를 활용하여 모델의 정확도와 일반화 성능을 판단한다. 일반화 성능이 낮은 모델의 경우 새롭게 받아들이게 되는 데이터에 대한 예측 정확도가 현저히 감소하게 되며 이러한 현상을 두고 모델이 과적합 되었다고 한다. 본 연구는 중심극한정리를 기반으로 데이터를 생성 및 기존의 훈련용 데이터와 결합하여 새로운 훈련용 데이터를 구성하고 데이터의 정규성을 증가시킴과 동시에 이를 활용하여 모델의 일반화 성능을 증가시키는 방법에 대한 것이다. 이를 위해 중심극한정리의 성질을 활용해 데이터의 각 특성별로 표본평균 및 표준편차를 활용하여 데이터를 생성하였고, 새로운 훈련용 데이터의 정규성 증가 정도를 파악하기 위하여 Kolmogorov-Smirnov 정규성 검정을 진행한 결과, 새로운 훈련용 데이터가 기존의 데이터에 비해 정규성이 증가하였음을 확인할 수 있었다. 일반화 성능은 훈련용 데이터와 테스트용 데이터에 대한 예측 정확도의 차이를 통해 측정하였다. 새롭게 생성된 데이터를 K-Nearest Neighbors(KNN), Logistic Regression, Linear Discriminant Analysis(LDA)에 적용하여 훈련시키고 일반화 성능 증가정도를 파악한 결과, 비모수(non-parametric) 기법인 KNN과 모델 구성 간 정규성을 가정으로 갖는 LDA의 경우에 대하여 일반화 성능이 향상되었음을 확인할 수 있었다.

• 한국자동차공학회논문집
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• 제14권1호
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• pp.129-137
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• 2006

This paper studies the effects of the swirl for the variation of intake port configuration that is key parameters in the flow field of direct injection diesel engines. In-cylinder flow characteristics is known to have significant effects on air-fuel mixing, combustion, and emissions. To investigate the effects of the swirl flow, various rpm(250, 500, 750) and two different intake port were used. And to evaluate the swirl motion in the flow field visualization engine, steady state flow test was conducted. Helical port intake port and SCV(Swirl Control Valve) were selected as the design parameters to increase the swirl flow and parametric study was performed. In the case of non-SCV, intake flow rate and non-dimensional swirl ratio were higher than those of SCV for the swirl head type. So, we could strengthen the swirl in the flow field with the swirl head type and don't using SCV. From the results of steady state flow test, non-swirl head type has the most good advantage for intake flow rate, and also the flow rate could be increased by using the SCV slightly. The effects of the type of engine head on intake air flow capability are dominant with respect to the existence of the SCV. We could measure the qualitative grade of swirl by capturing the scattering signal of microballoon from ICCD camera in the visualization diesel engine.

• 한국간담췌외과학회지
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• 제26권2호
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• pp.144-148
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• 2022

Backgrounds/Aims: Splenectomy in patients with non-Hodgkin lymphoma (NHL) is performed to relieve abdominal symptoms, treat hypersplenism or confirm diagnosis. Excision of a very large spleen is technically challenging and data on outcomes of surgery in patients with NHL are scanty. The aim of study was to evaluate the impact of spleen size on the surgical outcome of splenectomy in patients with NHL. Methods: Patients with NHL who underwent splenectomy, between 2006 and 2017, were included and divided into two groups: group 1, spleen ≤ 20 cm; group 2, spleen > 20 cm. Surgical approach, operative time, postoperative morbidity, mortality, hospital stay and re-admission rates were retrospectively compared between groups. Non-parametric data were evaluated with the Mann-Whitney U test. Differences in frequencies were analyzed with Fisher's exact test. Results: Sixteen patients were included (group 1, 6; group 2, 10). Laparoscopy was successful in three patients of group 1, none of group 2 (p = 0.035), the intraoperative time did not differ significantly between groups. One patient in each group developed postoperative complications. The patient in group 1 died of pneumonia. Median length of stay was 8 days (range, 3-16 days) for group 1, 5.5 days (range, 3-10 days) for group 2, showing no significant difference between the two groups. No patient was readmitted to hospital. Conclusions: Spleen size does not affect the outcome of splenectomy in patients with NHL. If a mini-invasive approach is to be chosen, laparoscopy may not be feasible when the spleen size is > 20 cm.

• 한국전문물리치료학회지
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• 제8권1호
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• pp.35-50
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• 2001

The purposes of this study were to investigate the therapeutic effects of an early exercise program after mastectomy and to provide the early exercise program protocol for patients who had undergone mastectomy. The subjects were seventy women who were diagnosed with breast cancer. They were randomly as signed either to a experimental group (n=35) that received early postoperative exercise program or to a control group (n=35) that received only education by nurses. Data were obtained for each patient from goniometric measurements of shoulder flexion, abduction, external rotation, 10 elements of functional performance, and subjective pain evaluation using visual analogue scale (VAS). All variables were measured preoperatively, three days postoperatively, and one month postoperatively. Data were compared by groups using independent t-test and Mann-Whitney U test for parametric or non-parametric data, respectively. There were no significant differences between the groups for all variables preoperatively and at three days postoperatively. But there were significant differences at one month postoperatively. The experimental group showed a statistically significant increases in shoulder flexion, abduction, and external rotation and in the pain VAS at one month postoperatively (p<.05). Also, at one month postoperatively, the experimental group had less difficulty with three elements of functional performance-doing up a 'back' zippered article of clothing, reaching the ipsilateral scapula, and contralateral scapula with the fingers on the operated side-than the control group (p<.05). The results of this study suggest that, after mastectomy, the early exercise program conducted by a well-trained physical therapist can make a significant contribution to the return of more normal shoulder function and activities of daily living and to an increased quality of life.

• Steel and Composite Structures
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• 제31권6호
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• pp.601-615
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• 2019

In cold-formed steel (CFS) structures, such as trusses, wall frames and columns, the use of back-to-back built-up CFS angle sections are becoming increasingly popular. In such an arrangement, intermediate fasteners are required at discrete points along the length, preventing the angle-sections from buckling independently. Limited research is available in the literature on the axial strength of back-to-back built-up CFS angle sections. The issue is addressed herein. This paper presents the results of 16 experimental tests, conducted on back-to-back built-up CFS screw fastened angle sections under axial compression. A nonlinear finite element model is then described, which includes material non-linearity, geometric imperfections and explicit modelling of the intermediate fasteners. The finite element model was validated against the experimental test results. The validated finite element model was then used for the purpose of a parametric study comprising 66 models. The effect of fastener spacing on axial strength was investigated. Four different cross-sections and two different thicknesses were analyzed in the parametric study, varying the slenderness ratio of the built-up columns from 20 to 120. Axial strengths obtained from the experimental tests and finite element analysis were used to assess the performance of the current design guidelines as per the Direct Strength Method (DSM); obtained comparison showed that the DSM is over-conservative by 13% on average. This paper has therefore proposed improved design rules for the DSM and verified their accuracy against the finite element and test results of back-to-back built-up CFS angle sections under axial compression.

• PNF and Movement
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• 제20권1호
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• pp.9-17
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• 2022

Purpose: The purpose of this study was to investigate the effect of chest mobilization and stretching exercises on maximal inspiratory pressure and maximal expiratory pressure in healthy adults who use computers for extended periods of time each day due to coronavirus disease 2019. Methods: Twenty-five healthy adults in their 20s and without respiratory disease (15 female, 10 male) took part in this study. Two types of thoracic mobilizing exercises using a Theraband and three types of stretching exercises using a foam roller were performed. Maximum inspiratory pressure and maximum expiratory pressure were measured three times each before and after the interventions. In terms of statistical methods, the maximum inspiratory pressure due to chest mobility and stretching was compared with the maximum expiratory pressure using parametric paired t-test and non-parametric Wilcoxon signed-rank test. Results: Maximum inspiratory pressure (p = .012) and maximum expiratory pressure (p = .006) showed significant differences before and after chest mobilization exercise and stretching among the participants. Conclusion: The results of this study suggest that chest mobilization and stretching exercises are effective exercise methods for improving maximal inspiratory and expiratory pressure. They suggest that these exercises can prevent respiratory muscle weakness and improve aerobic fitness in healthy people as well as those in need of cardiorespiratory physiotherapy.

• Restorative Dentistry and Endodontics
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• 제47권2호
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• pp.21.1-21.11
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• 2022

Objectives: This study aimed to investigate the bonding effects of cleaning protocols on dentin impregnated with endodontic sealer residues using ethanol (E) or xylol (X). The effects of dentin acid etching immediately (I) or 7 days (P) after cleaning were also evaluated. For bonding to dentin, universal adhesive (Scotchbond Universal; 3M ESPE) was used. The persistence of sealer residues, hybrid layer formation and microshear bond strength were the performed analysis. Materials and Methods: One hundred and twenty bovine dentin specimens were allocated into 4 groups (n = 10): G1 (E+I); G2 (X+I); G3 (E+P); and G4 (X+P). The persistence of sealer residues was evaluated by SEM. Confocal laser scanning microscopy images were taken to measure the formed hybrid layer using the Image J program. For microshear bond strength, 4 resin composite cylinders were placed over the dentin after the cleaning protocols. ANOVA followed by Tukey test and Kruskal-Wallis followed by Dunn test were used for parametric and non-parametric data, respectively (α = 5%). Results: G2 and G4 groups showed a lower persistence of residues (p < 0.05) and thicker hybrid layer than the other groups (p < 0.05). No bond strength differences among all groups were observed (p > 0.05). Conclusions: Dentin cleaning using xylol, regardless of the time-point of acid etching, provided lower persistence of residues over the surface and thicker hybrid layer. However, the bond strength of the universal adhesive system in etch-and-rinse strategy was not influenced by the cleaning protocols or time-point of acid etching.