• 대한인간공학회지
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• 제30권4호
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• pp.525-534
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• 2011

This paper describes the current status of musculoskeletal disorders(MSDs) and its ergonomic risk factors, including the preventive intervention in terms of the working conditions and health promotion among agricultural workers. Korean agricultural workers have been exposed to the poor working condition. They have suffered from a variety of work-related injury and diseases more than the general population or the other occupational group. MSDs are one of the most prevalent problems threatening the agricultural worker's health and quality of life. Low back pain, osteoarthritis of hip and knee joint and carpal tunnel syndrome are well known MSDs that was found easily and frequently among agricultural workers. MSDs are worsened by poor ergonomic working conditions such as heavy weight lifting, repetitive movement and awkward posture which involves squatting with long sitting work on the ground, long working hours and heavy workload which are inherent in the greater part of agricultural works. Even though Korean agricultural workers are very weak population in terms of occupational safety and health, no many studies were conducted in the past and no many social and institutional supports were provided sufficiently. We need more interests and efforts in agricultural fields to improve its working condition and to promote health status of agricultural workers.

• 한국도로학회논문집
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• 제19권4호
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• pp.1-7
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• 2017

PURPOSES : This study aims to improve complex modeling of multivariable, nonlinear, and overdispersion data with an artificial neural network that has been a problem in the civil and transport sectors. METHODS: Deep learning, which is a technique employing artificial neural networks, was applied for developing a large bus fuel consumption model as a case study. Estimation characteristics and accuracy were compared with the results of conventional multiple regression modeling. RESULTS : The deep learning model remarkably improved estimation accuracy of regression modeling, from R-sq. 18.76% to 72.22%. In addition, it was very flexible in reflecting large variance and complex relationships between dependent and independent variables. CONCLUSIONS : Deep learning could be a new alternative that solves general problems inherent in conventional statistical methods and it is highly promising in planning and optimizing issues in the civil and transport sectors. Extended applications to other fields, such as pavement management, structure safety, operation of intelligent transport systems, and traffic noise estimation are highly recommended.

• Smart Structures and Systems
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• 제16권2호
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• pp.367-382
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• 2015

This paper aims to conduct the reliability-based assessment of the welded joint in the orthotropic steel bridge deck by use of a mesh-insensitive structural stress (MISS) method, which is an effective numerical procedure to determine the reliable stress distribution adjacent to the weld toe. Both the solid element model and the shell element model are first established to investigate the sensitivity of the element size and the element type in calculating the structural stress under different loading scenarios. In order to achieve realistic condition assessment of the welded joint, the probabilistic approach based on the structural reliability theory is adopted to derive the reliability index and the failure probability by taking into account the uncertainties inherent in the material properties and load conditions. The limit state function is formulated in terms of the structural resistance of the material and the load effect which is described by the structural stress obtained by the MISS method. The reliability index is computed by use of the first-order reliability method (FORM), and compared with a target reliability index to facilitate the safety assessment. The results achieved from this study reveal that the calculation of the structural stress using the MISS method is insensitive to the element size and the element type, and the obtained structural stress results serve as a reliable basis for structural reliability analysis.

• Earthquakes and Structures
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• 제14권5호
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• pp.389-398
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• 2018

The seismic isolation system makes a structure isolated from ground motions to protect the structure from seismic events. Seismic isolation techniques have been implemented in full-scale buildings and bridges because of their simplicity, economic effectiveness, inherent stability and reliability. As for the responses of an isolated structure due to seismic events, it is well known that the most uncertain aspects are the seismic loading itself and structural properties. Due to the randomness of earthquakes and uncertainty of structures, seismic response distributions of an isolated structure are needed when evaluating the seismic fragility assessment (or probabilistic seismic safety assessment) of an isolated structure. Seismic response time histories are useful and often essential elements in its design or evaluation stage. Thus, a large number of non-linear dynamic analyses should be performed to evaluate the seismic performance of an isolated structure. However, it is a monumental task to gather the design or evaluation information of the isolated structure from too many seismic analyses, which is impractical. In this paper, a new methodology that can evaluate the seismic fragility assessment of an isolated structure is proposed by using stochastic response database, which is a device that can estimate the seismic response distributions of an isolated structure without any seismic response analyses. The seismic fragility assessment of the isolated nuclear power plant is performed using the proposed methodology. The proposed methodology is able to evaluate the seismic performance of isolated structures effectively and reduce the computational efforts tremendously.

• 한국전자통신학회논문지
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• 제6권6호
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• pp.815-822
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• 2011

본 논문은 다변화하고 있는 GMDSS 본연의 임무인 조난 및 긴급 안전과 병행하여 요구되고 있는 해상의 데이터통신 서비스를 위한 선박통신장비인 MF/HF, VHF, Inmarsat 위성통신 등 기존 탑재 장비들의 기능적 한계와 서비스 가능성을 확인하기 위한 데이터 통신 시스템을 설계 및 구현하였으며, 통신 매체별 통신비용, 처리율, 통신 속도, 처리 가능한 서비스, 통신 가능 범위 등에 대한 성능 분석 및 평가를 실시하여 미래 해상 통신 환경에서의 GMDSS의 역할과 방향을 제시하였다.

• KIEAE Journal
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• 제8권4호
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• pp.29-36
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• 2008

The rapid industrialization since the 1960s has caused considerable changes in the appearance of Korean cities. The huge demand and cityward tendency derived from the increase of population with such the expansion from 9 millions in 1960 to 43 millions in 2003, have resulted in number of problems such as the falling-off in the quality of life, amenity, and safety. And above all, the urban identities is not to be found obviously in the cities. With regard to these problems, the re-creation of cities should be emphasized to make environmental, economical, and social improvements and to restore human-oriented activities. In the course of making new improvements cities need to preserve the characteristics and maintain the concordance with their environments. In other words, the restoration of cities ought to be made in the aspect of continuity, which means the accession of genetic factors inherent in cities. In this background, concerning about the system on apartment house especially relating to environmentally sound restoration and comparing with that of Japan, this study proposes the direction needed in the development of urban space.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2006년도 춘계 학술발표회 논문집
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• pp.949-959
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• 2006

Despite of the popularity of using empirical methods for support design, empirical rules suffer from the inherent problem of providing no indication of the safety degree of the design. For the support design of large span tunnel, it was considered that the empirical design guidelines should be augmented by more explicit design methods. This paper presents an overview of the analytical support design methodology that is used to refine initial empirical recommendations. The initial support design supplemented by analytical methods is validated by probabilistic and deterministic approach applied to stress-induced and structurally controlled gravity-driven instability problem each. As a result, the extent of the potential failure zone is sorted out and numerical parametric studies were performed to gain insight into the overall behavior of tunnel in the potential failure zone. Concequently, it was decided that additional conservation techniques have to be planed as a reserved support pattern.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제55권9호
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• pp.485-490
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• 2006

According to the computerization of railway signaling systems, the interface link between the signaling systems has been replaced by the digital communication channel. At the same time, the importance of the communication link is more pronounced than before. In this paper, new Network-based protocol between railway signaling and SCADA (Supervisory Control and Data Acquisition system) has designed and the overview of designed protocol is briefly represented. And also this paper addresses analysis of newly designed train control systems. Fame error rates of the data transmissions are calculated and compared for the two cases that the CTC (Centralized Traffic Control)/SCADA has an extra data transmission error control (CRC16) besides the inherent error control of the Ethernet and that the CTC/SCADA has no extra data transmission error control. With simulation results it has been verified that the additional error control code contributes to lowering the frame error rate. It will be expected to increase the safety, reliability and efficiency of maintenance of the signaling systems by using the designed protocol for railway signaling system.

• 콘크리트학회논문집
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• 제15권6호
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• pp.924-929
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• 2003

A majority of infrastructures has been deteriorated over time. Therefore, it is very important to verify the quality of construction, and the level of structural deterioration in existing structures, to ensure their safety and functionality. Many researchers have studied non-destructive testing (NDT) methods to identify structural problems in existing structures. The impact echo technique is one of the widely used NDT techniques. The impact echo technique has several inherent problems, including the difficulties in P-wave velocity evaluation due to inhomogeneous concrete properties, deterioration of evaluation accuracy where multiple reflection boundaries exist, and the influence of the receiver location in evaluating the thickness of the tested structures. Therefore, the objective of this paper is to propose an enhanced impact echo technique that can reduce the aforementioned problems and develop a Virtual Instrument for the application via a thickness evaluation technique which has same technical background to find deterioration in concrete structures. In the proposed impact echo technique, transfer function from dual channel system analysis is used, and coherence is improved to achieve reliable data. Also an averaged signal -ensemble- is used to achieve more reliable results. From the analysis of transfer function, the thickness is effectively identified.

• Clinical and Experimental Pediatrics
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• 제60권8호
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• pp.237-244
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• 2017

During the last 10 years, there have been major technological achievements in pediatric interventional cardiology. In addition, there have been several advances in cardiac imaging, especially in 3-dimensional imaging of echocardiography, computed tomography, magnetic resonance imaging, and cineangiography. Therefore, more types of congenital heart diseases can be treated in the cardiac catheter laboratory today than ever before. Furthermore, lesions previously considered resistant to interventional therapies can now be managed with high success rates. The hybrid approach has enabled the overcoming of limitations inherent to percutaneous access, expanding the application of endovascular therapies as adjunct to surgical interventions to improve patient outcomes and minimize invasiveness. Percutaneous pulmonary valve implantation has become a successful alternative therapy. However, most of the current recommendations about pediatric cardiac interventions (including class I recommendations) refer to off-label use of devices, because it is difficult to study the safety and efficacy of catheterization and transcatheter therapy in pediatric cardiac patients. This difficulty arises from the challenge of identifying a control population and the relatively small number of pediatric patients with congenital heart disease. Nevertheless, the pediatric interventional cardiology community has continued to develop less invasive solutions for congenital heart defects to minimize the need for open heart surgery and optimize overall outcomes. In this review, various interventional procedures in patients with congenital heart disease are explored.