• 한국지진공학회논문집
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• 제20권1호
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• pp.33-43
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• 2016

This study investigates the performance of hollow precast segmental bridge columns with reinforcement details for material quantity reduction. The proposed triangular reinforcement details are economically feasible and rational, and facilitate shorter construction periods. The precast segmental bridge columns provides an alternative to current cast-in-place systems. We tested a model of hollow precast segmental bridge columns under a constant axial load and a quasi-static, cyclically reversed horizontal load. We used a computer program, Reinforced Concrete Analysis in Higher Evaluation System Technology (RCAHEST), for analysis of reinforced concrete structures. The used numerical method gives a realistic prediction of performance throughout the loading cycles for hollow precast segmental bridge column specimens investigated. As a result, proposed reinforcement details for material quantity reduction was equal to existing reinforcement details in terms of required performance.

• 한국건축시공학회지
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• 제19권6호
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• pp.557-566
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• 2019

건설업은 국내 산업 중 안전사고가 가장 많이 발생한다. 건설업의 재해는 막대한 재산손실과 인명피해로 인한 사회적 문제로 이어지기 때문에 더 각별한 주의를 기울여야 한다. 최근 이로 인해 건설업에서 발생하는 재해에 대한 경각심이 높아지고 있으며 정부 각 부처에서는 안전관리에 관한 규정을 강화하고 있다. 특히 산업안전보건공단에서는 이번 산업안전보건법 전부개정안에서 보호대상의 확대와 책임 소재의 명확화에 중점을 두고 있다. 이에 따라 발주자 책임강화에 따른 건설사업관리자 선정 시 안전을 고려하는 요인 중심으로 분석한 연구가 필요한 실정이다. 따라서 본 연구에서는 먼저, 성장하고 있는 건설사업관리 시장에 비해 증가하고 있는 건설재해에 대한 저감 대책 중 하나인 산업안전보건법 전부개정법률을 참고하였고, 다양한 건설사업의 특성과 안전 요인을 고려하지 않은 획일화된 건설사업관리용역업자 사업수행능력 평가기준을 개선하기 위해, 발주자의 입장에서 건설사업관리자를 선정할 때 안전에 대한 항목을 참고할 수 있도록 관련 요인을 도출하고 중요도를 분석해 새로운 평가의 기준점을 제시하고자 한다. 이를 위해 법령, 국내 논문 및 문헌, 해외 사례 등을 바탕으로 기존 연구와 문헌을 고찰하고, 전문가 면담을 통해 항목을 선정하였다. 선정된 항목은 4가지 상위요인 그룹으로 분류하여 총 19가지의 하위요인으로 정리하여 공공기관 및 민간사업 잘주처 관계자 및 건설사업관리업 종사자, 안전관리자에게 쌍대비교설문을 실시하였다. 수집된 설문조사 결과 데이터를 바탕으로 계층 분석적 방법인 AHP기법을 활용하여 상대적 중요도를 비교하고 우선순위를 분석해 최종적으로 안전을 고려한 건설사업관리 사업수행능력 평가기준에 필요한 요인을 도출하였다. 본 연구의 결과가 발주자 입장에서 건설사업관리자를 선정함에 있어 안전관리 요인을 고려할 수 있도록 도움이 되고 건설 산업 전체의 재해 저감에 기여할 수 있는 기초적인 자료로 활용되기를 기대한다.

• 대한토목학회논문집
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• 제39권5호
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• pp.623-630
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• 2019

아시아 건설시장의 전략적 중요성이 높아지면서 기업 간 경쟁이 더욱 치열해지고 있다. 기존의 아시아 건설시장에 대한 연구는 주요 국가로의 진출전략 도출, 분야별 리스크 평가에 대한 정성적 접근이 주류를 이루었던 반면, 다수 기업의 역동적인 경쟁구도를 정량적으로 설명한 연구는 드물었다. 이에 본 연구는 국내 건설기업이 2009년부터 2017년까지 계약을 체결한 3,996건의 프로젝트 정보를 바탕으로 아시아 지역의 계약실적 구조를 분석하였다. 정태적 분석에는 시장 집중도, 동태적 분석에는 시장 이동성 및 불안정성 개념을 각각 활용하였으며, 이에 대한 수학적 모델을 소개하였다. 분석 결과, 정태적 측면에서는 아시아 건설시장에서 국내 상위 기업군의 시장 점유율 집중 현상이 나타나고 있으며, 동태적 측면에서는 산업설비 공종을 제외한 대부분의 경우 시장 지위가 약하고 안정성이 떨어지는 것으로 밝혀졌다. 본 연구에서 제시한 분석 방법론과 결과는 산업 차원의 실적에 대한 체계적 진단을 가능케 하며, 향후 경쟁전략 수립을 위한 기초자료를 제공하였다는 점에서 의의가 있다.

• Safety and Health at Work
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• 제13권3호
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• pp.364-371
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• 2022

Background: Respiratory masks can provide healthcare workers with protection from biological hazards when they have good performance. There is a direct relationship between the visual specifications of a mask and its efficacy; thus, the aim of this study was to develop tools for qualitative assessment of the performance of masks used by healthcare workers. Methods: A mixed-methods design was used to develop a qualitative assessment tool for medical face masks (MFM) and particle filtering half masks (PFHM). The development of domains and items was undertaken using observation and interviews, the opinions of an expert panel, and a review of texts and international standards. The second phase evaluated the psychometric properties of tools. Finally, the validated Mask Qualitative Assessment Tools (MQAT) were used to assess six samples from 10 brands of the two types of masks. Results: MQAT-MFM and MQAT-PHFM shared 42 items across seven domains: "cleanliness," "design," "marking, labeling and packaging," "mask layers," "mask strap," "materials and construction," and "nose clip." MQAT-MFM included one additional item. MQAT-PHFM included another nine items associated with an eighth "Practical Performance" domain, and the valve version had another additional "Exhalation Valve" domain and six items. The evaluation indicated 80% compliance for MFM and 71% compliance for PFHM. "Marking, labeling and packaging" and "Layers" were associated with the least compliance in both types of masks and should be checked carefully for defining mask quality. Conclusion: MQAT can be used for immediate screening and initial assessment of MFM and PHFM through appearance, simple tools, and visual inspection.

• Wind and Structures
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• 제31권5호
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• pp.381-392
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• 2020

Despite that the failure of sign structure may not have disastrous consequence, its sheer number still ensures the need for rigorous safety standard to regulate their maintenance and construction. During its service life, a sign structure is subject to extensive wind load, sometimes well over its permissible design load. A fragility analysis of a sign structure offers a tool for rational decision making and safety evaluation by using a probabilistic framework to consider the various sources of uncertainty that affect its performance. Wind fragility analysis was used to determine the performance of sign structure based on the performance of its connection components. In this study, basic wind fragility concepts and data required to support the fragility analysis of the sign structure such as sign panel's parameters, connection component's parameters, as well as wind load parameters were presented. Fragility and compound fragility analysis showed disparity between connection component. Additionally, reinforcement of the connection system was introduced as an example of the utilization of wind fragility results in the retrofit decision making.

• Structural Monitoring and Maintenance
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• 제10권3호
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• pp.191-205
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• 2023

In this paper, through operational modal analysis and ambient vibration tests, the dynamic characteristics of a multi-span simply-supported reinforced concrete highway bridge deck was determined and the results were used to assess the quality of construction of the individual spans. Supporting finite element (FE) models were created and analyzed according to the design drawings. After carrying out the dynamic tests and extracting the modal properties of the deck, the quality of construction was relatively assessed by comparing the results obtained from all the tests from the individual spans and the FE results. A comparison of the test results among the different spans showed a maximum difference value of around 9.3 percent between the superstructure's natural frequencies. These minor differences besides the obtained values of modal damping ratios, in which the differences were not more than 5 percent, can be resulted from suitable performance, health, and acceptable construction quality of the bridge.

• 국제학술발표논문집
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• The 6th International Conference on Construction Engineering and Project Management
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• pp.685-686
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• 2015

The world is currently undergoing an intense urbanization process. The percentage of urban dwellers has never been so high. In 2010, and for the first time, urban population surpassed the rural one, accounting for 51% of global population, and this trend will continue in the forthcoming years. This increment in concentration of population and supporting assets in cities, make their performance a critical issue for world population. Recent events such as Fukushima tsunami and the hurricane Katrina have shown how fragile built environments are and the unpredictability of occurrence and magnitude of the hazards. Such an expansion of the world's urban population, together with an increase in severity and number of hazards and catastrophes, has put under the spotlight the necessity to build cities not only sustainable, but resilient. Decision makers should acknowledge failure as an option, and the importance of developing city resilience. This paper will provide an initial review on urban resilience, definitions and assessment approaches as a first step for decision makers to account for resilience in their decision making process.

• International journal of advanced smart convergence
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• 제12권2호
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• pp.159-166
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• 2023

Due to the aging workforce in the construction industry in South Korea, the accident rate has been increasing. The cognitive abilities of older workers are closely related to both safety incidents and labor productivity. Therefore, there is a need to improve cognitive abilities through personalized training based on cognitive assessment results, using cognitive training content, in order to enable safe performance in labor-intensive environments. The provided cognitive training content includes concentration, memory, oreintation, attention, and executive functions. Difficulty levels were applied to each content to enhance user engagement and interest. To stimulate interest and encourage active participation of the participants, the difficulty level was automatically adjusted based on feedback from the MMSE-DS results and content measurement data. Based on the accumulated data, individual training scenarios have been set differently to intensively improve insufficient cognitive skills, and cognitive training programs will be developed to reduce safety accidents at construction sites through measured data and research. Through such simple cognitive training, it is expected that the reduction of accidents in the aging construction workforce can lead to a decrease in the social costs associated with prolonged construction periods caused by accidents.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2007년도 동계학술발표대회 논문집
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• pp.149-154
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• 2007

Now, in Korea, the performances of the building service equipment relay on the individual superintendent's share for the assessment of performance, fault detection, deterioration diagnosis of the building service equipment. As the result, very different quality of the performance or the durability of equipment is being obtained with his skill and effort and it is also not easy to assess that quality. This finally lead to the waste of labor force and the operating cost due to the high-cost, low-efficiency system. How to construct the N-BMS was considered to save energy, resource and to conserve performance of building service equipment. The FEMIS, facility, energy/environmental management & information system, for building service offer management process integrated with BAS, FMS and EMS and so on.

• 국제학술발표논문집
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• The 6th International Conference on Construction Engineering and Project Management
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• pp.564-567
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• 2015

The incorporation of sustainability principles into the structural engineering design of buildings is increasingly important. Historically the focus of improvements to the environmental performance of structures has been operational energy considerations. Current research has highlighted the requirement for changing the approach by increasing the consideration of embodied energy in structures. This research was conducted to build on previous research by the authors in quantifying the contribution of column optimization to the embodied energy performance of concrete framed buildings. Ultimately, the authors intend to develop mechanisms through which sustainable design can be quantified, enabling alleviation prior to construction. Columns are a key structural element to consider as part of this development process. The outcomes of this assessment reinforced previous findings, observing that reduced structural weight as a result of other sustainable design measures carries manifold benefits include column design savings. Through the quantification of the embodied energy outcomes during this research phase, the columns were shown to contribute up to 19.71% of the total embodied energy of the structural system dependent upon construction technique used.