• Smart Structures and Systems
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• 제12권3_4호
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• pp.291-308
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• 2013

A novel concept of transmissibility based on a wavelet transform for structural damage detection is presented in this paper. The main objective of the research was the development of a method for detecting slight damage at the incipient stage. As a vibration-based approach, the concept of transmissibility has attracted considerable interest because of its advantages and effectiveness in damage detection. However, like other vibration-based methods, transmissibility-based approaches suffer from insensitivity to slight local damage because of the regularity of the traditional Fourier transform. Therefore, the powerful signal processing techniques must be found to solve this problem. Wavelet transform that is able to capture subtle information in measured signals has received extensive attention in the field of damage detection in recent decades. In this paper, we first propose a novel transmissibility concept based on the wavelet transform. Outlier analysis was adopted to construct a damage detection algorithm with wavelet-based transmissibility. The feasibility of the proposed method was numerically investigated with a typical six-degrees-of-freedom spring-mass system, and comparative investigations were performed with a conventional transmissibility approach. The results demonstrate that the proposed transmissibility is more sensitive than conventional transmissibility, and the former is a promising tool for structural damage detection at the incipient stage.

• Nuclear Engineering and Technology
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• 제29권1호
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• pp.78-84
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• 1997

The specific purpose of this study is to develop the numerical guide for the cost-benefit analysis of ORE ($/person-Sv reduction) to meet the criterion of ALARA in the design stage of the KNGR. In deriving the guide, the risk factor which is defined by the risk to unit collective radiation exposure dose (deaths/person-Sv) and the monetary value of human life ($/death) are required. The risk factor has been estimated from various clinical data accumulated for a number of years and continuously modified. And the monetary value of human life is usually quantified using the human capital approach. In this study, the risk to radiation exposure perceived by a group of people is investigated through an extensive poll survey conducted among university students in order to modify the existing risk factor for radiation exposure. And in evaluating the monetary value of human life, the QOL factor is introduced in order to incorporate the degree of public welfare or quality of life. As a result of study, a value within the range of 151, 000~172, 000 dollars per person-Sv reduction is recommended as the appropriate interim numerical guide for cost-benefit analysis of ORE to meet the criterion of ALARA in the design stage of the KNGR. A poll survey was also conducted in order to see whether the public acceptance cost of nuclear power should be incorporated in developing the guide, and the result of study shooed that such a cost does not need to be considered.

• Smart Structures and Systems
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• 제18권3호
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• pp.625-642
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• 2016

The rapid technology developments in smartphones have created a significant opportunity for their use in structural live load measurements. This paper presents extensive experiments conducted in two stages to investigate this opportunity. Shaking table tests were carried out in the first stage using selected popular smartphones to measure the sinusoidal waves of various frequencies, the sinusoidal sweeping, and earthquake waves. Comparison between smartphone measurements and real inputs showed that the smartphones used in this study gave reliable measurements for harmonic waves in both time and frequency domains. For complex waves, smartphone measurements should be used with caution. In the second stage, three-dimensional motion capture technology was employed to explore the capacity of smartphones for measuring the movement of individuals in walking, bouncing and jumping activities. In these tests, reflective markers were attached to the test subject. The markers' trajectories were recorded by the motion capture system and were taken as references. The smartphone measurements agreed well with the references when the phone was properly fixed. Encouraged by these experimental validation results, smartphones were attached to moving participants of this study. The phones measured the acceleration near the center-of-mass of his or her body. The human-induced loads were then reconstructed by the acceleration measurements in conjunction with a biomechanical model. Satisfactory agreement between the reconstructed forces and that measured by a force plate was observed in several instances, clearly demonstrating the capability of smartphones to accurately assist in obtaining human-induced load measurements.

• 대한조선학회논문집
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• 제30권3호
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• pp.1-15
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• 1993

국내외적인 여건 변화와 향후 초고속선 해상 수송시대에 대비한 세계 각국의 초고속선 개발에 대처하기 위하여 당사 선박해양연구소에서는 3단계 고속선 개발계획을 수립한 바 있다. 그 1단계 사업으로 300인 이상의 승객을 태우고 최고 속도 40노트 이상으로 왕복 800해리의 장거리를 운항할 수 있는 "장거리 고속 수중익 쌍동여객선"을 개발하여 건조하게 되었다. 본 장거리 고속 수중익 쌍동여객선의 설계과정을 통하여 국내에서는 최초로 기능별 최적화와 성능확인을 위한 방대한 양의 이론적 분석과 모형시험이 체계적으로 이루어졌다.

• 한국간호교육학회지
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• 제27권2호
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• pp.117-131
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• 2021

Purpose: This study is a qualitative study that investigated the nature of Koreans' spiritual health using a hybrid model, clarifying the definition and attributes of the concept. Methods: The nature and definition of Koreans' spiritual health were identified through a review of the extensive literature at the theoretical stage and then compared with an analysis of the in-depth interview data conducted by the researcher in the fieldwork stage. Results: Koreans' spiritual health comprised nine attributes: awareness of the meaning and purpose of life, self-awareness, self-acceptance and recognition, self-transcendence, self-integration, harmony of relationships, self-actualization and development, the inner affective attributes of hope, happiness, fulfillment and thankful mind, and the interpersonal affective attributes of one connected mind, compassion, generosity and humility. The scope of the Absolute is expanded to 'heaven' and 'ancestors', and harmony with the community is emphasized. Conclusion: We have found that Koreans' spiritual health is important for total nursing care and that mental, social and physical health can be improved if spiritual health is promoted. Considering this point, personal and organizational efforts are needed to ensure that spiritual nursing is positively applied in community and clinical settings.

• 대한간호학회지
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• 제48권6호
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• pp.637-655
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• 2018

Purpose: The purpose of this qualitative study is to investigate the nature of tacit nursing knowledge practiced in the clinical field in Korea using hybrid models, and to clarify the definitions and attributes of the concept. Methods: The definition and nature of tacit nursing knowledge, obtained through a review of the extensive literature at the theoretical stage of the research, and the analysis of the in-depth interview data conducted by the career nurses in the fieldwork stage, are compared and analyzed. Results: The tacit nursing knowledge was found in three dimensions as knowledge related to the person, the clinical situation work context, the self, the others, and the task. The tacit nursing knowledge was defined as personal nursing knowledge and artistic skills that show up as unconscious behavior patterns, learned informally, and internalizedthrough repeated clinical practice experience based on professional nursing knowledge. Conclusion: Tacit nursing knowledge has been widely used in clinical practice and has been shown to have a great impact, directly or indirectly, on clinical nursing. Therefore, individual and organizational efforts are needed for validation and clarification using the generation, sharing, collection, and peer review of sound implicit nursing knowledge to ensure that it is properly applied.

• Steel and Composite Structures
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• 제39권4호
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• pp.419-433
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• 2021

In composite structures, shear connectors are crucial components to resist the relative slip between the steel and concrete, and thereby to achieve the composite actions. In the service stage, composite structures are usually in elastic state, so the elastic stiffness of the shear connection is a quite important parameter in the structural analysis of composite structures. Nevertheless, the existing studies mainly focus on the load-slip relationship rather than the tangent stiffness at the initial elastic stage. Furthermore, when composite beams subjected to torque or local load, shear connections are affected by both tensile force and shear force. However, the stiffness of shear connections under combined effects appears not to have been discussed hitherto. This paper investigates the initial elastic stiffness of stud connections under combined effects of biaxial forces. The initial expression and the relevant parameters are obtained by establishing a simplified analytical model of the stud connection. Afterwards, parametric finite element analysis is performed to investigate the effects of the relevant factors, including the stud length, stud diameter, elastic modulus of concrete, elastic modulus of steel and volume ratio of reinforcement. The feasibility of the proposed modelling has been proved by comparing with sufficient experimental tests. Based on the analytical analysis and the extensive numerical simulations, design equations for predicting the initial elastic stiffness of stud connections are proposed. The comparison between the equations and the data of finite element models demonstrates that the equations are accurate enough to serve for engineering communities.

• 국제학술발표논문집
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• The 9th International Conference on Construction Engineering and Project Management
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• pp.94-102
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• 2022

Construction workers are engaged in many activities that may expose them to serious hazards, such as falling, unguarded machinery, or being struck by heavy construction equipment. Despite extensive research in building information modeling (BIM) for safety management, current approaches, detecting safety issues after design completion, may limit the opportunities to prevent predictable and potential accidents when decisions of building materials and systems are made. In this respect, this research proposes a proactive approach to detecting safety issues from the early design phase. This research aims to explore accident precursors and integrate them into BIM for tracking safety hazards during the design development process. Accident precursors can be identified from construction incident reports published by OSHA using a text mining technique. Through BIM-integrated accident precursors, construction safety hazards can be identified during the design phase. The results will contribute to supporting a successful transition from the design stage to the construction stage that considers a safe construction workplace. This will advance the body of knowledge about construction safety management by elucidating a hypothesis that safety hazards can be detected during the design phase involving decisions about materials, building elements, and equipment. In addition, the proactive approach will help the Architecture, Engineering and Construction (AEC) industry eliminate occupational safety hazards before near-miss situations appear on construction sites.

• 대한한의학회지
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• 제43권4호
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• pp.74-88
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• 2022

Objectives: The purpose of this study is to design Korean-themed online public education content in Korean medicine using rapid prototyping instructional systems design (RPISD). This study presents cases of developing and converting face-to-face general education programs designed to increase the interest in and understanding of Korean medicine for the public into online programs within a short timeframe. Methods: This qualitative study is design and development research, which used the RPISD model to analyze the available resources utilized in the rapid development of public educational content and propose systematization and optimization measures by analyzing the needs of clients, learners, and the environment. The <Treasured Mirror of Eastern Medicine(DUBG)Open Course> was developed according to the model procedure, which involved needs analysis, development of course materials and manuscript, and storyboard creation and its filming and editing. Usability tests were conducted at all stages, and the opinions of clients, instructors, experts, and instructional designers were accommodated and reflected at each stage. Results: Using the rapid prototyping model, <Treasured Mirror of Eastern Medicine(DUBG)Open Course> was organized into five classes of 20 minutes each. Each class was developed in Korean and included English, Chinese, and Japanese subtitles in addition to Korean under the cooperative instructional design among clients, subject-matter experts, instructional designer and learners. Conclusion: The cooperative instructional design of stakeholders is significant in developing Korean medicine public education content online through extensive interaction and feedback from stakeholders in the early stage of educational content development.

• 한국지구과학회지
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• 제33권3호
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• pp.242-258
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• 2012

황해 경기만은 제4기에 반복된 해침과 해퇴로 4개의 해침-해퇴 퇴적체(DS-1, DS-2, DS-3, DS-4)를 형성하였다. 본 연구는 황해 경기만 퇴적체의 형성을 6개 퇴적단계로 나누어 설명한다. A 단계는 MIS-6 저해수면 시기로서 큰 규모의 해수면 하강으로 인해 대부분의 지역이 대기에 노출되고 광범위한 하도 침식 및 풍화작용의 영향을 받았다. 이어지는 B 단계는 MIS-5e 까지 빠른 해수면 상승과정에서 MIS-5 시퀀스의 하부 해침퇴적체가 형성되었고, 다음에 이어지는 MIS-5d부터 MIS-4 저해수면 시기까지의 C 단계에서는 MIS-5 시퀀스의 상부인 해퇴퇴적체가 만들어졌다. 다음의 D 단계는 MIS-4 저해수면 시기부터 MIS-3c 고해수면 시기까지로 하도 침식 및 하도 충전 구조로 이루어진 MIS-3 해침 퇴적체가 형성되었다. 다음의 E 단계에서는 LGM 시기까지 계속적인 해수면 하강이 있었고 외해쪽에서는 천해 기원의 MIS-3 해퇴퇴적체가 만들어진 반면에, 내륙쪽에서는 노출된 환경에서 하도 충전 퇴적체나 범람원 퇴적체가 형성되었다. 마지막 단계인 F 단계는 황해 전체적으로 홀로세 해침이 발생하였고, 이 시기에 외해쪽에서는 대륙붕 사질 퇴적체와 조석사주 퇴적체가 형성되어 고해수면 시기인 현재까지 퇴적이 일어나고 있다.