• Smart Structures and Systems
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• v.3 no.4
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• pp.475-494
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• 2007

This paper deals with the development of an innovative distributed construction system based on smart prefabricated concrete elements for the real-time condition assessment of civil infrastructure. So far, two reduced-scale prototypes have been produced, each consisting of a $0.2{\times}0.3{\times}5.6$ m RC beam specifically designed for permanent instrumentation with 8 long-gauge Fiber Optic Sensors (FOS) at the lower edge. The sensing system is Fiber Bragg Grating (FBG)-based and can measure finite displacements both static and dynamic with a sample frequency of 625 Hz per channel. The performance of the system underwent validation in the laboratory. The scope of the experiment was to correlate changes in the dynamic response of the beams with different damage scenarios, using a direct modal strain approach. Each specimen was dynamically characterized in the undamaged state and in various damage conditions, simulating different cracking levels and recurrent deterioration scenarios, including cover spalling and corrosion of the reinforcement. The location and the extent of damage are evaluated by calculating damage indices which take account of changes in frequency and in strain-mode-shapes. The outcomes of the experiment demonstrate how the damage distribution detected by the system is fully compatible with the damage extent appraised by inspection.

• Nuclear Engineering and Technology
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• v.42 no.5
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• pp.546-551
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• 2010

The objective of this research is to estimate the crack location and size of a carbon steel pipe by using a laser ultrasound guided wave for the wall thinning evaluation of an elbow. The wall thinning of the carbon steel pipe is one of the most serious problems in nuclear power plants, especially the wall thinning of the carbon steel elbow caused by Flow-Accelerated Corrosion (FAC). Therefore, a non-destructive inspection method of elbow is essential for the nuclear power plants to operate safely. The specimens used in this study were carbon steel elbows, which represented the main elements of real nuclear power plants. The shape of the wall thinning was an oval with a width of 120mm, a length of 80mm, and a depth of 5mm. The L(0,1) and L(0,2) modes variation of the ultrasound guided wave signal is obtained from the response of the laser generation/air-coupled detection ultrasonic hybrid system represent the characteristics of the defect. The trends of these characteristics and signal processing were used to estimate the size and location of wall thinning.

• Journal of Korean Clinical Nursing Research
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• v.23 no.1
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• pp.64-72
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• 2017

Purpose: This study aimed to explore the distributions of nurse staffing grades and to report changes in staffing grades in general wards and adult and neonatal intensive care units(ICUs) by hospital type and location. Methods: Data collected from the Health Insurance Review and Assessment Service were analyzed. Nurse staffing was categorized from grades 1 to 6 or 7 for general wards, 1 to 9 for adult ICUs, and 1 to 4 for neonatal ICUs based on the nurse-to-bed ratio. Results: The staffing grade for the general wards improved during 2008-2016 in 69.8% of the tertiary hospitals, 58.5% of the general hospitals, and 31.7% of the non-general hospitals. The adult ICUs at tertiary hospitals exhibited a greater improvement in staffing grades (48.8%) than did those of general hospitals (44.2%) during 2008-2015. Tertiary hospitals in non-capital regions showed a greater improvement than those in the capital region. The majority of neonatal ICUs (67.1%) had no change in the staffing grade during 2008-2015. Conclusion: Improvements in nurse staffing differed by hospital type and location. Government policies to improve nurse staffing in non-tertiary hospitals and those in non-capital regions are required to reduce variations in nurse staffing.

• Journal of Korean Academy of Nursing
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• v.47 no.5
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• pp.676-688
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• 2017

Purpose: The purpose of this study was to analyze the migration patterns of new nurses and experienced nurses and to identify the factors influencing inter-regional migration for solving regional imbalances of clinical nurses in South Korea. Methods: This study involved a secondary analysis of data from the Health Insurance Review and Assessment Service (HIRA). Data were analyzed using descriptive statistics and multiple logistic regression analysis. Results: New nurses tended to migrate from Kyunggi to Seoul. However, experienced nurses tended to migrate from Seoul and Chungchung to Kyunggi. Significant predictors of inter-regional migration among new nurses were location and nurse staffing grade of hospitals. Significant predictors of inter-regional migration among experienced nurses were location, hospital type, nurse staffing grade, ownership of hospitals and age of nurses. Conclusion: Inter-regional migration occupied a small portion of total hospital movement among clinical nurses. The regional imbalances of nurses were not caused by the migration from non-metropolitan areas to Seoul. Nurse shortage problems in the small and medium hospitals of the non-metropolitan area can be solved only through improvement of work environment.

• Imaging Science in Dentistry
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• v.40 no.2
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• pp.59-62
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• 2010

Purpose : To investigate and compare the prevalence, size, and location of maxillary sinus septa on panoramic and cone beam computed tomography (CBCT) images. Materials and Methods : Two hundred patients who had taken both panoramic and CBCT images were included. The location of maxillary sinus septa on the panoramic radiographs were recorded and confirmed on the CBCT images. Also the size of septa was measured on the reformatted CBCT images. Results : The prevalence of the patients who had maxillary sinus septa was 51.0% and they showed 179 septa totally. Among them 51.0% of the patients had one septum, 32.4% two septa, 13.7% three, and 2.9% four. The measured heights of the septa were $4.37{\pm}2.87\;mm$, $3.51{\pm}2.47\;mm$, and $3.04{\pm}2.37\;mm$ in the medial, middle, and lateral areas, respectively. It was revealed that 1.0% was located at canine region, 18.0% at first premolar, 25.0% at second premolar, 22.7% at first molar, 19.8% at second molar, and 14.0% at third molar region. Among 213 septa depicted by the panoramic radiographs, only 69.0% were confirmed at the CBCT images. Conclusion : Since various heights and courses of the septa can develop in all parts of the maxillary sinus, adequate assessment of the inner aspect of the maxillary sinus is essential to avoid complications during sinus augmentation procedures. CBCT scanning is the preferred radiographic method for detecting the presence of sinus septa.

• Journal of the Korean Institute of Rural Architecture
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• v.8 no.2
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• pp.1-10
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• 2006

Recently the concerns of landscape resources were on the increase about the landscape of control and landscape design. In order to this, purpose of this paper is to develop architectural landscape design data of individual house in Gangwon Provinces. The type of landscape in Donghae seaside consist of three; Road, Mountain, Seaside. And the type of images about individual housing are three; Western, Traditional, Modern. This research is analyzed 18-simulation scenes, factor analysis is used for the SPSS. The results of this study are as follows. First, the housing of western style do not correspond with landscape of Road, but landscape of mountain and seaside were suitable to the western style. Second, mountain in Donghae seaside harmonizes with housing of traditional style. Third, even though the housing of modern style were marked low assessment in three landscape, we found out relation, modern housing was well-matched load landscape. Finally, to improve of landscape housing, which will serve as systematic approach with association of clients, constructors, designers and public service personnel.

• Structural Monitoring and Maintenance
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• v.2 no.4
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• pp.399-418
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• 2015

Automated damage detection through Structural Health Monitoring (SHM) techniques has become an active area of research in the bridge engineering community but widespread implementation on in-service infrastructure still presents some challenges. In the meantime, visual inspection remains as the most common method for condition assessment even though collected information is highly subjective and certain types of damage can be overlooked by the inspector. In this article, a Frequency Response Functions-based model updating algorithm is evaluated using experimentally collected data from the University of Central Florida (UCF)-Benchmark Structure. A protocol for measurement selection and a regularization technique are presented in this work in order to provide the most well-conditioned model updating scenario for the target structure. The proposed technique is composed of two main stages. First, the initial finite element model (FEM) is calibrated through model updating so that it captures the dynamic signature of the UCF Benchmark Structure in its healthy condition. Second, based upon collected data from the damaged condition, the updating process is repeated on the baseline (healthy) FEM. The difference between the updated parameters from subsequent stages revealed both location and extent of damage in a "blind" scenario, without any previous information about type and location of damage.

• Earthquakes and Structures
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• v.14 no.6
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• pp.589-598
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• 2018

An attempt is conducted to explore the relationship between the macroscopic global damage and the local damage of shear-type RC frames. A story damage index, which can be expressed as multi-variate functions of modal parameters, is deduced based on the tridiagonal matrix of the shear-type frame. The global damage model is also originated from structural modal parameters. Due to the connection of modal damage indexes, the relationship between the macroscopic global damage and the local story damage is reasonably established. In order to validate the derivation, a case study is carried out via an 8-story shear-type frame. The sensitivities of modal damage indexes to the location and severity of local story damages are studied. The evolution of the global damage is investigated as well. Results show that the global damage is sensitive to the degree of story damage, but it's not sensitive to its location. As the number of the damaged stories increases, more and more modes will be involved. Meanwhile, the global damage evolution curve changes from the concave shape to the S-type and then finally transforms into the convex shape. Through the proposed story damage, modal damage and global damage model, a multi-level damage assessment method is established.

• Journal of Hydrogen and New Energy
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• v.30 no.6
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• pp.499-504
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• 2019

Due to the rapid spread and low minimum ignition energy of hydrogen, rupture is highly likely to cause fire, explosion and major accidents. The self-ignition of high-pressure hydrogen is highly likely to ignite immediately when it leaks from an open space, resulting in jet fire. Results of the diffusion and leakage simulation show that jet effect occurs from the leakage source to a certain distance. And at the end of location, the vapor cloud explosion can be occurred due to the formation of hydrogen vapor clouds by built-up. In the result, it is important that depending on the time of ignition, a jet fire or a vapor cloud explosion may occur. Therefore, it is necessary to take into account jet effect by location of leakage source and establish a damage minimizing plan for the possible jet fire or vapor cloud explosion. And it is required to any kind of measurements such as an interlock system to prevent hydrogen leakage or minimize the amount of leakage when detecting leakage of gas.

• Smart Structures and Systems
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• v.24 no.5
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• pp.617-630
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• 2019

Currently most of the vision-based structural identification research focus either on structural input (vehicle location) estimation or on structural output (structural displacement and strain responses) estimation. The structural condition assessment at global level just with the vision-based structural output cannot give a normalized response irrespective of the type and/or load configurations of the vehicles. Combining the vision-based structural input and the structural output from non-contact sensors overcomes the disadvantage given above, while reducing cost, time, labor force including cable wiring work. In conventional traffic monitoring, sometimes traffic closure is essential for bridge structures, which may cause other severe problems such as traffic jams and accidents. In this study, a completely non-contact structural identification system is proposed, and the system mainly targets the identification of bridge unit influence line (UIL) under operational traffic. Both the structural input (vehicle location information) and output (displacement responses) are obtained by only using cameras and computer vision techniques. Multiple cameras are synchronized by audio signal pattern recognition. The proposed system is verified with a laboratory experiment on a scaled bridge model under a small moving truck load and a field application on a footbridge on campus under a moving golf cart load. The UILs are successfully identified in both bridge cases. The pedestrian loads are also estimated with the extracted UIL and the predicted weights of pedestrians are observed to be in acceptable ranges.