• Structural Engineering and Mechanics
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• 제81권5호
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• pp.647-664
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• 2022

The powerful data mapping capability of computational deep learning methods has been recently explored in academic works to develop strategies for structural health monitoring through appropriate characterization of dynamic responses. In many cases, these studies concern laboratory prototypes and finite element models to validate the proposed methodologies. Therefore, the present work aims to investigate the capability of a deep learning algorithm called Sparse Autoencoder (SAE) specifically focused on detecting structural alterations in real-case studies. The idea is to characterize the dynamic responses via SAE models and, subsequently, to detect the onset of abnormal behavior through the Shewhart T control chart, calculated with SAE extracted features. The anomaly detection approach is exemplified using data from the Z24 bridge, a classical benchmark, and data from the continuous monitoring of the San Vittore bell-tower, Italy. In both cases, the influence of temperature is also evaluated. The proposed approach achieved good performance, detecting structural changes even under temperature variations.

• 국제초고층학회논문집
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• 제1권1호
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• pp.37-51
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• 2012

New generation of tall and complex buildings systems are now introduced that are reflective of the latest development in materials, design, sustainability, construction, and IT technologies. While the complexity in design is being overcome by the availability and advances in structural analysis tools and readily advanced software, the design of these buildings are still reliant on minimum code requirements that yet to be validated in full scale. The involvement of the author in the design and construction planning of Burj Khalifa since its inception until its completion prompted the author to conceptually develop an extensive survey and real-time structural health monitoring program to validate all the fundamental assumptions mad for the design and construction planning of the tower. The Burj Khalifa Project is the tallest structure ever built by man; the tower is 828 meters tall and comprises of 162 floors above grade and 3 basement levels. Early integration of aerodynamic shaping and wind engineering played a major role in the architectural massing and design of this multi-use tower, where mitigating and taming the dynamic wind effects was one of the most important design criteria established at the onset of the project design. Understanding the structural and foundation system behaviors of the tower are the key fundamental drivers for the development and execution of a state-of-the-art survey and structural health monitoring (SHM) programs. Therefore, the focus of this paper is to discuss the execution of the survey and real-time structural health monitoring programs to confirm the structural behavioral response of the tower during construction stage and during its service life; the monitoring programs included 1) monitoring the tower's foundation system, 2) monitoring the foundation settlement, 3) measuring the strains of the tower vertical elements, 4) measuring the wall and column vertical shortening due to elastic, shrinkage and creep effects, 5) measuring the lateral displacement of the tower under its own gravity loads (including asymmetrical effects) resulting from immediate elastic and long term creep effects, 6) measuring the building lateral movements and dynamic characteristic in real time during construction, 7) measuring the building displacements, accelerations, dynamic characteristics, and structural behavior in real time under building permanent conditions, 8) and monitoring the Pinnacle dynamic behavior and fatigue characteristics. This extensive SHM program has resulted in extensive insight into the structural response of the tower, allowed control the construction process, allowed for the evaluation of the structural response in effective and immediate manner and it allowed for immediate correlation between the measured and the predicted behavior. The survey and SHM programs developed for Burj Khalifa will with no doubt pioneer the use of new survey techniques and the execution of new SHM program concepts as part of the fundamental design of building structures. Moreover, this survey and SHM programs will be benchmarked as a model for the development of future generation of SHM programs for all critical and essential facilities, however, but with much improved devices and technologies, which are now being considered by the author for another tall and complex building development, that is presently under construction.

• 천문학회보
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• 제27권2호
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• pp.48-48
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• 2002

• 대한지역사회영양학회지
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• 제22권5호
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• pp.401-412
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• 2017

Objectives: The purpose of this study was to investigate the current status of parents' monitoring of school lunch programs and to examine the relationship of parents' school lunch monitoring with their level of trust in school lunch programs. Methods: During November 2016, a web survey was conducted with 1,283 parents who had participated in monitoring of school lunch programs. A total of 621 parents completed the questionnaires (48.4% response rate) and the responses from 442 parents were analyzed (34.5% analysis rate) for elementary (n=196) and middle/high school parents (n=246), respectively. Results: Both the elementary and middle/high school parents most wanted to participate in monitoring 1~2 times per month, which was less frequent than their current practice. They showed the highest experience rate in 'food sanitation' area in both the prior training and actual practice of school lunch monitoring. They most responded 'increasing trust in school lunch programs' as a merit and 'lack of parents participating in monitoring' as a problem of school lunch monitoring. The average levels of trust did not differ between elementary and middle/high school parents. Multiple regression analyses showed that elementary school parents' level of satisfaction in the monitored school lunch programs was positively associated with the parents' level of trust in general school lunch programs. Monitoring frequency and parents' age, in addition to level of satisfaction in the monitored school lunch program, were associated with level of trust in general school lunch programs among middle/high school parents. Conclusions: There was room for change in parents' school lunch monitoring programs to meet parents' needs better. Well-managed school lunch monitoring programs contributing to parents' satisfaction with school lunch programs could increase parents' level of trust in school lunch programs.

• 대한영양사협회학술지
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• 제20권2호
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• pp.123-132
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• 2014

This study investigated the effect of food consumption monitoring and real-time communication-based weight control program using a smartphone on weight reduction and maintenance in obese women. This study consisted of two phases: an 8-week weight control program with food consumption monitoring and real-time communication using a smartphone and an 8-week follow-up. Sixteen obese female college students (>30% body fat) participated in this program, and we measured changes in body composition and dietary intake volume. Follow-up analysis focused on weight maintenance after 8 weeks of no contact. Total energy intake (P<0.01), body weight (P<0.001), percent body fat (P<0.001), body fat (P<0.05), and body mass index (P <0.001) decreased significantly after the 8-week weight control program. However, we could not observe total energy intake or body composition regain after the follow-up period. These results suggest that food consumption monitoring and real-time communication using a smartphone can be effective for weight control and maintenance.

• 한국안전학회지
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• 제33권1호
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• pp.109-117
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• 2018

This study examined the effect of Behavior Based Safety(BBS) program on safe behaviors of bus drivers and passengers. Four male bus drivers working at a H transportation company situated in Seoul participated in this study. BBS program consisted of education, prompts, and self-monitoring with goal setting. Dependent variables were the percentage of two safe driving behaviors of bus drivers (departure after stopping for 3 seconds, announcement for holding bus handles) and the percentage of one safe behavior of passengers getting on the busses those drivers drove (holding bus handles). A primary observer and two trained assistant observers measured two safe behaviors of the bus drivers with behavior checklists by riding on the busses and the passengers' safe behavior was observed by CCTV installed on each bus. An ABC multiple baseline design across participants was adopted. After baseline(A), education and prompts(B) and self-monitoring with goal setting(C) were introduced sequentially to each participant. The results showed that BBS program was effective to increase both bus drivers' and passengers' safe behaviors. Especially self-monitoring with goal setting was more effective in improving safe behaviors of bus drivers than education/prompts. These results suggest that education/prompts and self-monitoring with goal setting would be an alternative treatment technique to improve safety for lone workers such as bus drivers.

• 에너지공학
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• 제24권2호
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• pp.179-186
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• 2015

에너지효율등급제 사후관리의 시행내용에 대해서 분석해 보았다. 이를 바탕으로 국내 사후관리제에 대한 개선방안을 제시하였다. 첫째, 사후관리 위반정도가 심한 제품, 반복적 위반업체의 해당모델에 대해 지속적으로 포함하고, 판매시장에서 구입하는 방식으로 적용되어야 할 것이다. 둘째, 사후관리 대상모델에 대한 점검결과를 반영하여 위반 발생빈도에 따라 제품별 사후관리 점검방식의 개선을 강구하는 것이 바람직하다. 셋째, 사후관리 점검결과 부적합률 또는 반복적 위반사례가 지속되는 경우 수시점검의 실시가 필요하다. 끝으로, 사후관리 점검결과에 대한 현재 관보 게재 및 보도자료 공개에서 사후관리 전과정에 대한 상세보고서까지 관계 유관기관에 공고 및 인터넷 공개로 확대하는 것이 요청된다.

• 대한의용생체공학회:의공학회지
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• 제35권3호
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• pp.55-61
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• 2014

In sleep monitoring system, polysomnography (PSG) is the gold-standard but previous studies revealed that attaching numerous amount of sensors disturb sleep during the test which is the fundamental disadvantage of PSG. We suggest an unconstrained rapid-eye-movement (REM) sleep monitoring method measured with polyvinylidene (PVDF) film-based sensor for the normal and the obstructive sleep apnea (OSA) patients. Nine normal subjects and seventeen OSA patients have participated in the study. During REM sleep, rate and variability of respiration are known to be greater than in other sleep stages. Based on this phenomena, respiratory signals of participants were unconstrainedly measured using the PVDF-based sensor with the PSG and REM sleep were extracted from the average rate and variability of respiration. In epoch-by-epoch REM sleep detection, proposed method classified REM sleep with an average sensitivity of 72.3%, specificity of 92.5%, accuracy of 88.9%, and kappa statistic of 0.60 compared to the results of PSG. Student's t-test showed no significant difference between the results of normal and OSA group. This method is potentially applicable to REM sleep detection in homing environment or ambulatory monitoring.

• Nuclear Engineering and Technology
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• 제27권4호
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• pp.555-561
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• 1995

이 논문에서는 영광 3호기와 같이 노심내 핵계장 장치를 갖고 있는 가압형 원자력 발전소용 노심출력 분포 감시프로그램의 개발에 수정형 Borresen 모형의 응용 타당성을 검토해 보았다 이를 위해 수정형 Borresen 방정식의 소격모형해를 핵계장장치의 측정치를 경계조건으로 하여 풀었으며, 이로부터 영광 3호기 첫주기 노심의 3차원 출력분포를 계산하였다. 그 결과는 현재 영광 3호기의 축방향 출력분포 감시프로그램으로 활용되고 있는 COLSS 예측치와 비교하였으며, 이를 통하여 수정형 Borresen 모형으로 제안한 방법이 COLSS보다 축방향 출력분포를 실제에 더 가깝게 모사할 수 있음을 보였다. 노심 출력거동에 대한 예측능력이 있고 또한 전산속도면에서의 이점이 있어서 제안된 수정형 Borresen 방법이 노심출력분포 감시프로그램 개발에 유용하게 활용될 수 있다고 결론을 내렸다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 춘계학술대회 논문집
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• pp.470-475
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• 2011

The objective of this study is the developement health & disaster monitoring measurement using ubiquitous active communication digital datalogger system for monitoring measurement of railway construction sites. For the replacement of current passive data communication, ubiquitous active communication digital datalogger system is studied for the first time with in a country. Therefore data communication method and analyzing program of automatic measurement data is developed for the global positioning automatic digital datalogger system. The results of this study will be using both real time automatic monitoring measurement and health & disaster monitoring measurement of railway structures.