• 자원ㆍ환경경제연구
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• 제31권2호
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• pp.233-260
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• 2022

본 연구에서는 비모수적 분위수 인과관계 검정 방법을 이용하여 국제유가의 변동이 산업별 주가의 움직임에 어떤 영향을 주는지 분석하였다. 본 연구의 분석 대상은 1998년 1월부터 2021년 4월까지 WTI 가격, KOSPI 지수 및 18개 산업별 주가지수의 주별 데이터이다. 비모수 분위수 인과 검정 결과에서 유가 변화가 KOSPI 지수에 미치는 영향은 유의하지 않은 것으로 나타났다. 이는 KOSPI 지수에 포함된 여러 산업의 주가 반응이 서로 다르기 때문이라고 생각된다. 유가 변화에 대한 산업별 주가지수의 반응을 살펴보면, 주식 수익률을 0.1분위부터 0.9분위까지 0.05단위로 나눈 인과관계 결과에서 전체 18개 산업 중 섬유의복, 종이목재, 의약품 등을 포함한 9개 산업에서 인과성이 유의하게 나타났으며, 나머지 9개 산업에서는 유가와의 인과성을 보이지 않았다. 이 산업들 중 세 분위 이상에 걸쳐 연속적으로 인과성이 나타난 산업은 의약품과 통신업(0.45분위 ~ 0.85분위), 섬유의복(0.15분위 ~ 0.45분위), 건설업(0.5분위 ~ 0.6분위) 등 4개 산업으로 인과성이 나타난 구간은 업종마다 차이가 있다. 검정결과를 통해 유가의 변화에 대한 주가 반응에는 산업별로 큰 차이가 있었고, 한 산업에서도 시장 상황에 따라 다르게 나타남을 알 수 있다. 이것은 유가 변화 시기에 투자자들은 포트폴리오를 산업별로 재조정할 필요가 있음을 보여준다. 또한, 정부의 산업정책과 고용정책 등 거시경제정책도 유가 변화 영향이 산업별, 시장 상황별로 차이나는 점을 충분히 고려하여 운영되어야 할 것이다.

• 대한물리의학회지
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• 제8권4호
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• pp.513-523
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• 2013

PURPOSE: The purpose of this study was to investigate characteristics of the forced pulmonary function test effect and abdominal muscles activation by combined complex exercise with abdominal drawing-in maneuver training of chronic stroke patients. METHODS: 14 post stroke patients(10 males and 4 females) involved voluntary this study and we divided two groups into CEG(complex exercise group) and CEAG (complex exercise and abdominal drawing-in maneuver group).(n=7, per goup). Each groups implicated the 2 times, 30minute exercises for 6 weeks a day. The CEAG performed the complex exercise 15 minutes and 15 minutes of abdominal drawing-in maneuver. For data analysis, the mean and standard deviation were estimated; non-parametric independent t-test was carried out. RESULTS: According to the study, in the combined complex exercise with abdominal drawing-in maneuver group, FVC and activation of transversus abdominis/internal oblique were statistically significant difference compared to the complex exercise group. CONCLUSION: These results indicate that the combined complex with abdominal drawing-in maneuver was efficient in enhancing abdominal muscles activation and pulmonary function of chronic stroke patients.

• The Journal of Korean Physical Therapy
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• 제29권3호
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• pp.142-144
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• 2017

Purpose: Few studies have addressed the effect of diurnal circadian rhythms on postural stability, and thus the aim of the present study was to examine circadian effects on static and dynamic postural stability in young adults. Methods: Twenty-four subjects (9 men, 11 women: age=$22.20{\pm}1.77$, height=$167.20{\pm}10.47$, weight=$59.85{\pm}10.66$) from a university community volunteered for this study. Static and dynamic balance testing, which recorded using a Good Balance system (Good Balance, Metitur Ltd, Finland) was conducted at 9:00, 13:00, and 17:00 hours on two consecutive days, and the sequencing of static and dynamic balance tests were randomized. Results were analyzed using the non-parametric one-way repeated Friedman test in SPSS version 18.0 (SPSS Inc., Chicago, IL, USA), and variable found to be significant were subjected to Wilcoxon post hoc testing. Results: Static and dynamic balance showed significant difference at the three times assessments (test at 9:00, 13:00, and 17:00) during circadian. In the post hoc test of static (anteroposterior distance, mediolateral distance and COP (center of pressure) velocity) and dynamic balance (performance time), 13:00 was the longer and faster than 9:00. Conclusion: These results indicated that control of postural balance is influenced by diurnal circadian rhythms, and confirm that control of postural balance is more effective and better performance in the 09:00 hours than 13:00 hours or 17:00 hours.

• Environmental Engineering Research
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• 제21권1호
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• pp.58-68
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• 2016

The study explored droughts using the Standardized Precipitation Index (SPI) in the northwestern region of Bangladesh, which is the drought prone area. In order to assess the trend and variability of monthly rainfall, as well as 3-month scale SPI, non-parametric Mann-Kendall (MK) tests and continuous wavelet transform were used respectively. The effect of climatic parameters on the drought in this region was also evaluated using SPI, with the Southern Oscilation Index (SOI) by means of the wavelet coherence technique, a relatively new and powerful tool for describing processes. The MK test showed no statistically significant monthly rainfall trends in the selected stations, whereas the seasonal MK test showed a declining rainfall trend in Bogra, Ishurdi, Rangpur and Sayedpur stations respectively. Sen's slope of six stations also provided a decreasing rainfall trend. The trend of the SPI, as well as Sen's slope indicated an increasing dryness trend in this area. Dominant periodicity of 3-month scale SPI at 8 to 16 months, 16 to 32 months, and 32 to 64 months were observed in the study area. The outcomes from this study contribute to hydrologists to establish strategies, priorities and proper use of water resources.

• Structural Engineering and Mechanics
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• 제70권4호
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• pp.431-443
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• 2019

The present paper illustrates a numerical investigation on the failure behaviour of ring-stiffened cylinder subjected to external hydrostatic pressure. The published test data of steel welded ring-stiffened cylinder are surveyed and collected. Eight test models are chosen for the verification of the modelling and FE analyses procedures. The imperfection as the consequences of the fabrication processes, such as initial geometric deformation and residual stresses due to welding and cold forming, which reduced the ultimate strength, are simulated. The results show that the collapse pressure and failure mode predicted by the nonlinear FE analyses agree acceptably with the experimental results. In addition, the failure mode parameter obtained from the characteristic pressure such as interframe buckling pressure known as local buckling pressure, overall buckling pressure, and yield pressure are also examined through the collected data and shows a good correlation. A parametric study is then conducted to confirm the failure progression as the basic parameters such as the shell radius, thickness, overall length of the compartment, and stiffener spacing are varied.

• Steel and Composite Structures
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• 제48권2호
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• pp.131-143
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• 2023

The CFRP bar was used to achieve more ductile and durable headed-stud shear connectors in composite components. Three series of push-out tests were firstly conducted, including specimens reinforced with pure steel fibers, steel and CFRP bars. The distributed stress was measured by the commercial PPP-BOTDA (Pre-Pump-Pulse Brillouin optical time domain analysis) optical fiber sensor with high spatial resolution. A series of numerical analyses using non-linear FE models were also made to study the shear force transfer mechanism and crack response based on the test results. Test results show that the CFRP bar increases the shear strength and stiffness of the large diameter headed-stud shear connection, and it has equivalent reinforcing effects on the stud shear capacity as the commonly used steel bar. The embedded CFRP bar can also largely improve the shear force transfer mechanism and decrease the tensile stress in the transverse direction. The parametric study shows that low content steel fibers could delay the crack initiation of slab around the large diameter stud, and the CFRP bar with normal elastic modulus and the standard reinforcement ratio has good resistance to splitting crack growth in headed stud shear connectors.

• 한국ITS학회 논문지
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• 제21권5호
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• pp.103-116
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• 2022

국토교통부는 원활한 자율주행자동차 서비스 확대를 위해 총 7개 지역을 자율주행자동차 시범운행지구로 지정·고시하여 매년 운영성과에 대한 평가를 받도록 하였다. 본 연구는 이를 위한 기초연구로서 자율주행자동차 서비스의 정성적 만족도를 설문조사 기반으로 평가하였다. 첫째, 세종시 자율주행 서비스 이용자와 일반인을 대상으로 자율주행 서비스 인식에 대한 설문조사를 실시하였다. 그 결과, 자율주행 서비스 이용자가 자율주행 기술에 대한 단계 인지, 이용 의향 등이 일반인에 비해 높게 나타났다. 둘째, 수요대응형 대중교통 서비스 이용자와 세종시 자율주행 서비스 이용자를 대상으로 서비스 만족도 설문조사를 실시하였다. 비모수통계분석 방법 중 윌콕슨 순위합 검정(Wilcoxon Rank Sum Test)을 통한 분석 결과, 자율주행 서비스 이용자의 경우 안전과 관련된 요인들이 전반적인 만족도에 영향을 미치는 것으로 나타났다. 반면, 수요대응형 대중교통 서비스 이용자들은 서비스 편의성과 관련된 항목들이 전반적인 만족도에 영향을 미치는 것으로 나타났다. 이러한 설문조사 결과는 향후 자율주행 서비스의 개선사항 및 정책수립에 대한 기초자료로 활용이 기대된다.

• Journal of Periodontal and Implant Science
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• 제46권4호
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• pp.266-276
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• 2016

Purpose: The aim of the present study was to retrospectively investigate the influence of potential risk indicators on the development of peri-implant disease. Methods: Overall, 103 patients referred for implant treatment from 2000 to 2012 were randomly enrolled. The study sample consisted of 421 conventional-length (>6 mm) non-turned titanium implants that were evaluated clinically and radiographically according to preestablished clinical and patient-related parameters by a single investigator. A non-parametric Mann-Whitney U test or Kruskal-Wallis rank test and a logistic regression model were used for the statistical analysis of the recorded data at the implant level. Results: The diagnosis of peri-implant mucositis and peri-implantitis was made for 173 (41.1%) and 19 (4.5%) implants, respectively. Age (${\geq}65$ years), patient adherence (professional hygiene recalls <2/year) and the presence of plaque were associated with higher peri-implant probing-depth values and bleeding-on-probing scores. The logistic regression analysis indicated that age (P=0.001), patient adherence (P=0.03), the absence of keratinized tissue (P=0.03), implants placed in pristine bone (P=0.04), and the presence of peri-implant soft-tissue recession (P=0.000) were strongly associated with the event of peri-implantitis. Conclusions: Within the limitations of this study, patients aged ${\geq}65$ years and non-adherent subjects were more prone to develop peri-implant disease. Therefore, early diagnosis and a systematic maintenance-care program are essential for maintaining peri-implant tissue health, especially in older patients.

• Journal of Audiology & Otology
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• 제23권3호
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• pp.121-128
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• 2019

Background and Objectives: There is a scant evidence on the use of simulations in audiology (especially in Malaysia) for case-history taking, although this technique is widely used for training medical and nursing students. Feedback is one of the important components in simulations training; however, it is unknown if feedback by instructors could influence the simulated patient (SP) training outcome for case-history taking among audiology students. Aim of the present study is to determine whether the SP training with feedback in addition to the standard role-play and seminar training is an effective learning tool for audiology case-history taking. Subjects and Methods: Twenty-six second-year undergraduate audiology students participated. A cross-over study design was used. All students initially attended two hours of seminar and role-play sessions. They were then divided into three types of training, 1) SP training (Group A), 2) SP with feedback (Group B), and 3) a non-additional training group (Group C). After two training sessions, the students changed their types of training to, 1) Group A and C: SP training with feedback, and 2) Group B: non-additional training. All the groups were assessed at three points: 1) pre-test, 2) intermediate, and 3) post-test. The normalized median score differences between and within the respective groups were analysed using non-parametric tests at 95% confidence intervals. Results: Groups with additional SP trainings (with and without feedback) showed a significantly higher normalized gain score than no training group (p<0.05). Conclusions: The SP training (with/without feedback) is a beneficial learning tool for history taking to students in audiology major.

• 대한청각학회지
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• 제23권3호
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• pp.121-128
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• 2019

Background and Objectives: There is a scant evidence on the use of simulations in audiology (especially in Malaysia) for case-history taking, although this technique is widely used for training medical and nursing students. Feedback is one of the important components in simulations training; however, it is unknown if feedback by instructors could influence the simulated patient (SP) training outcome for case-history taking among audiology students. Aim of the present study is to determine whether the SP training with feedback in addition to the standard role-play and seminar training is an effective learning tool for audiology case-history taking. Subjects and Methods: Twenty-six second-year undergraduate audiology students participated. A cross-over study design was used. All students initially attended two hours of seminar and role-play sessions. They were then divided into three types of training, 1) SP training (Group A), 2) SP with feedback (Group B), and 3) a non-additional training group (Group C). After two training sessions, the students changed their types of training to, 1) Group A and C: SP training with feedback, and 2) Group B: non-additional training. All the groups were assessed at three points: 1) pre-test, 2) intermediate, and 3) post-test. The normalized median score differences between and within the respective groups were analysed using non-parametric tests at 95% confidence intervals. Results: Groups with additional SP trainings (with and without feedback) showed a significantly higher normalized gain score than no training group (p<0.05). Conclusions: The SP training (with/without feedback) is a beneficial learning tool for history taking to students in audiology major.