• 국제학술발표논문집
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• The 9th International Conference on Construction Engineering and Project Management
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• pp.1245-1246
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• 2022

Walkability is an indicator of how much pedestrians are willing to walk and how well a walking environment is created. As walking can promote pedestrians' mental and physical health, there has been increasing focus on improving walkability in different ways. Thus, plenty of research has been undertaken to measure walkability. When measuring walkability, there are many objective and subjective variables. Subjective variables include a feeling of safety, pleasure, or comfort, which can significantly affect perceived walkability. However, these subjective factors are difficult to measure by making the walkability index more reliant on objective and physical factors. Because many subjective variables are associated with human emotional states, understanding pedestrians' emotional states provides an opportunity to measure the subjective walkability variables more quantitatively. Pedestrians' emotions can be examined through surveys, but there are social and economic difficulties involved when conducting surveys. Recently, an increasing number of studies have employed physiological data to measure pedestrians' stress responses when navigating unpleasant environmental barriers on their walking paths. However, studies investigating the emotional states of pedestrians in the walking environment, including assessing their positive emotions felt, such as pleasure, have rarely been conducted. Using wearable devices, this study examined the various emotional states of pedestrians affected by the walking environment. Specifically, this study aimed to demonstrate the feasibility of monitoring biometric data, such as electrodermal activity (EDA) and heart rate variability (HRV), using wearable devices as an indicator of pedestrians' emotional states-both pleasant-unpleasant and aroused-relaxed states. To this end, various walking environments with different characteristics were set up to collect and analyze the pedestrians' biometric data. Subsequently, the subjects wearing the wearable devices were allowed to walk on the experimental paths as usual. After the experiment, the valence (i.e., pleasant or unpleasant) and arousal (i.e., activated or relaxed) scale of the pedestrians was identified through a bipolar dimension survey. The survey results were compared with many potentially relevant EDA and HRV signal features. The research results revealed the potential for physiological responses to indicate the pedestrians' emotional states, but further investigation is warranted. The research results were expected to provide a method to measure the subjective factors of walkability by measuring emotions and monitoring pedestrians' positive or negative feelings when walking to improve the walking environment. However, due to the lack of samples and other internal and external factors influencing emotions (which need to be studied further), it cannot be comprehensively concluded that the pedestrians' emotional states were affected by the walking environment.

• 한국산림과학회지
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• 제112권4호
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• pp.544-553
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• 2023

활엽수림은 여름철에 착엽을 통해 일사를 차단하여 열 스트레스를 완화하는 역할을 하는 것으로 알려져 있지만, 이와 관련된 데이터의 축적은 부족한 실정이다. 따라서 본 연구는 여름철 활엽수림에서의 휴식이 온열환경 쾌적성 및 인체의 생리・심리적 반응에 미치는 영향을 분석하는 것을 목적으로 하였다. 연구대상자는 남녀 대학생 32명(21.5±2.1세)으로 하였다. 연구대상자는 두 명이 한 조를 이루어 각각 실험지(수관울폐도: 76.6%)와 대조실험지(25.9%)로 이동하였고, 일련의 실험과정을 이후 장소를 교대하여 같은 실험을 진행하였다. 실험과정은 다음과 같다. 연구대상자는 의자에 앉아 휴식한 후, 눈을 감고 5분 동안 안정을 취하였다. 이때의 온열환경 쾌적성을 평가하고 심박변이도, 심박수, 이마체온을 연속적으로 측정하였다. 이후 혈압 및 맥박수를 측정하였으며, 주관평가를 진행하였다. 그 결과, 실험지는 통계적으로 유의미한 예상평균한서감지수 및 예상불만족률의 감소, 부교감신경활동의 증가, 심박수・이마체온・이완기혈압・맥박수의 감소가 나타났으며, 주관적 온열감 및 쾌적감이 개선되었다. 결론적으로, 수관울폐도가 높은 활엽수림은 여름철 온열 스트레스를 감소시키며, 인체를 생리・심리적으로 안정시킨다는 것을 확인하였다.

• 한국정보통신학회논문지
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• 제14권11호
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• pp.2435-2441
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• 2010

본 논문에서는 M2M 기반의 글로벌 헬스케어 모니터링 시스템을 구축하여 헬스케어 분야에 있어 기존의 센서네트워크의 확장성과 이동성을 보완하여 더욱더 안정적이고 신뢰성 있는 건강상태 정보를 제공하고자 하였다. 센서 노드는 웨어러블 심전도 및 맥파 센서와 결합되어 있으며, 각각의 생체신호를 수집하여 IEEE 802.15.4 표준 프로토콜과 6LoWPAN 프로토콜을 통해 외부 인터넷 망을 거쳐 서버로 전송한다. 또한 서버 프로그램은 측정된 생체신호를 통해 HRV 신호를 검출하였으며, HRV 신호를 이용한 시간 영역 및 주파수 영역 분석을 통해 환자의 스트레스 상태를 판단하도록 하였다. 이로써 제안된 시스템은 기존의 네트워크 인프라를 최대한 활용할 수 있는 장점을 가지고 있으며, 각각의 센서노드에 IP를 부여하여 헬스케어 서비스의 적용범위가 좁은 지역을 벗어나 범국가적으로 확대될 수 있도록 하였다.

• Wind and Structures
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• 제23권6호
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• pp.505-521
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• 2016

The objective of this study is to investigate numerically the effect of building roof shaps on wind flow and pollutant dispersion in a street canyon with one row of trees of pore volume, $P_{vol}=96%$. A three-dimensional computational fluid dynamics (CFD) model is used to evaluate air flow and pollutant dispersion within an urban street canyon using Reynolds-averaged Navier-Stokes (RANS) equations and the Explicit Algebraic Reynolds Stress Models (EARSM) based on k-${\varepsilon}$ turbulence model to close the equation system. The numerical model is performed with ANSYS-CFX code. Vehicle emissions were simulated as double line sources along the street. The numerical model was validated by the wind tunnel experiment results. Having established this, the wind flow and pollutant dispersion in urban street canyons (with six roof shapes buildings) are simulated. The numerical simulation results agree reasonably with the wind tunnel data. The results obtained in this work, indicate that the flow in 3D domain is more complicated; this complexity is increased with the presence of trees and variability of the roof shapes. The results also indicated that the largest pollutant concentration level for two walls (leeward and windward wall) is observed with the upwind wedge-shaped roof. But the smallest pollutant concentration level is observed with the dome roof-shaped.

• Computers and Concrete
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• 제3권1호
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• pp.1-15
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• 2006

The seismic safety of reinforced concrete containment building can be evaluated by probabilistic analysis considering randomness of earthquake, which is more rational than deterministic analysis. In the safety assessment of earthquake-resistant structures by the deterministic theory, it is not easy to consider the effects of random variables but the reliability theory and random vibration theory are useful to assess the seismic safety with considering random effects. The reliability assessment of reinforced concrete containment building subjected to earthquake load includes the structural analysis considering random variables such as load, resistance and analysis method, the definition of limit states and the reliability analysis. The reliability analysis procedure requires much time and labor and also needs to get the high confidence in results. In this study, random vibration analysis of containment building is performed with random variables as earthquake load, concrete compressive strength, modal damping ratio. The seismic responses of critical elements of structure are approximated at the most probable failure point by the response surface method. The response surface method helps to figure out the quantitative characteristics of structural response variability. And the limit state is defined as the failure surface of concrete under multi-axial stress, finally the limit state probability of failure can be obtained simply by first-order second moment method. The reliability analysis for the multiaxial strength limit state and the uniaxial strength limit state is performed and the results are compared with each other. This study concludes that the multiaxial failure criterion is a likely limit state to predict concrete failure strength under combined state of stresses and the reliability analysis results are compatible with the fact that the maximum compressive strength of concrete under biaxial compression state increases.

• Journal of Acupuncture Research
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• 제24권4호
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• pp.13-23
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• 2007

Objectives : The aim of the present study was to assess the effects of Sa-am acupuncture (Damjeonggyeok) on autonomic nervous system in night nurses by heart rate variability. Methods : Five night nurses were divided into two groups. We checked their HRV once after sleeping for night and 5 times after working for night, 4 times after operation. We operate Sa-am acupuncture (Damjeonggyeok) and sham acupuncture twice by turns for group A and in reverse order for group B. We checked responses of HRV change after operations. Statistical analysis was performed by using the SPSS Win. Ver. 13.0 for analysis about correlation between data, and Baysian analysis using WinBUGS(Ver. 1.4) for comparison between Sa-am acupuncture (Damjeonggyeok) and sham acupuncture. Results : The median overall decrease for difference in responses of low-frequency power in normalized units (LF (NU)) was -16.56 (-28.88, -6.446), the median overall increase for difference in responses to high-frequency power in normalized units (HF (NU)) was 16.25 (8.104, 28.6) and for the median overall decrease for difference in responses to the ratio of low- to high-frequency power (LF/HF) was -1.846 (-3.922, -0.069), 95% credibility intervals being shown in brackets. VAS of stress was correlated with LF (NU) and HF (NU), LF/HF (p<0.0l). Conclusion : Sa-am acupuncture (Damjeonggyeok) might have sympatholytic and parasympathomimetic effects.

• 사상체질의학회지
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• 제23권4호
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• pp.487-502
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• 2011

1. Objective This study was performed to research the biological change of forest healing according to Sasang constitution. 2. Methods Forty seven applicants are involved in this study. They were classified into three groups(Soyangin, Taeeumin, Soeumin) by QSCC II. And then they participated in forest healing program from March 26 to March 27 in 2011. We performed before and after experiment, including vital sign, electroencephalography(EEG), heart rate variability(HRV), complete blood cell count(CBC), biochemical test(BC), and stress hormones. 3. Results Men had the relaxative effect of tension. While, the group of women and Soyangin was more sensitive to sudden environmental change than the group of men or other constitutions. The tension of women and soyangin's group increased after the forest healing program. Soeumin group showed reduced diastolic blood pressure after the forest healing program. 3. Conclusions Forest healing program has shown better efficacy in relaxation in men than women, in lowering diastolic blood pressure in Soeumin group than other constitutional groups. However a single positive result within this study should be carefully interpreted.

• 대한기계학회논문집A
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• 제37권9호
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• pp.1109-1116
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• 2013

본 연구의 목적은 마찰교반용접된 7075-T651 알루미늄 합금 용접부에 대한 피로균열전파율의 공간적 불규칙성을 고찰하기 위한 것이다. 본 연구에서는 이전의 피로균열전파 실험 데이터를 활용하였다. 피로균열전파율의 공간적 불규칙성을 명확히 이해하기 위하여, 피로균열전파 실험은 일정 응력확대 계수범위 제어하에서 수행되었다. 재질, 즉 마찰교반용접된 7075-T651 알루미늄 합금 용접부의 용접재와 모재에 대하여 피로균열전파율의 공간적 불규칙성을 조사하기 위하여 실험 데이터가 해석되었다. 결론적으로 용접재의 변동성이 모재의 변동성보다 높게 나타났으며, Weibull 통계 해석에 의하여 변동성을 평가할 수 있음을 알았다.

• 대한물리의학회지
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• 제10권1호
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• pp.9-14
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• 2015

PURPOSE: The purpose of this study was to investigate the effects of ten minutes of manual passive exercise performed by physical therapists on autonomic nervous system. METHODS: Thirty-five healthy adults, both male and female, were chosen as subjects for this study. The autonomic nervous system was measured by heart rate variability (HRV),before and after passive exercise using the following measurements: mean heart rate (mean HRT), low frequency (LF) and high frequency (HF) components, the LF/HF ratio, root mean square of the successive differences (RMSSD), and the HRV index. The exercise was performed on the subjects by a physical therapist with seven years of experience specializing in the nervous system. The exercise was conducted at the mid-range of motion on the upper and lower limbs of the subjects for two minutes and thirty seconds and for a total of ten minutes. RESULTS: There was a significant increase in the LF component. The mean HRT and the LF/HF ratio both increased, but these increases were not significant. The HF component, RMSSD, and HRV index all decreased, but these decreases were not significant. CONCLUSION: In conclusion, mid-range manual passive exercise does not induce stress on the autonomic nervous system. It can safely be performed by a physical therapist.

• 한국산학기술학회논문지
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• 제8권5호
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• pp.1186-1191
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• 2007

본 연구는 교차형 와이드 거더를 이용한 건축구조로 최소한의 슬래브 두께로 가능한 최장의 스팬을 확보할 수 있도록 함으로써, 층고를 높이지 않으면서 실내 공간에 자유롭고 다양한 변화를 가져올 수 있도록 하는 것이다. 즉, 본 연구는 교차형 와이드 거더를 응력분포에 따라 일정 간격으로 연속 배치함으로써, 낮은 층고에서 해당 경계 공간을 무주 공간으로 형성시킬 수 있도록 하는 것이다 본 연구의 수치적 타당성을 검토하기 위하여 3차원 횡력 설계가 가능한 프로그램인 Midas Gen을 이용하여 기존의 벽체 시스템과 교차형 Wide Girder에 의한 연성골조 시스템을 해석한 결과, 구조적으로 횡변위 및 층간변위와 바닥의 처짐 등이 기존의 벽체시스템과 비교하여 크게 불리하지 않으며, 전체적인 콘크리트 물량이 기존 벽체시스템과 비슷하며 건축적인 가변성을 확보하는데 큰 장점이 있는 것으로 나타났다.