• Steel and Composite Structures
• /
• v.32 no.3
• /
• pp.305-312
• /
• 2019

In this study, we investigated the effect of fatigue crack propagation of the beams which have a vital importance in engineering applications, on the natural frequency of the system. Beams which have a wide range of applications, are used as fundamental structural elements in engineering structures. Therefore, early detection of any damages in these structures is of vital importance for the prevention of possible destructive damages. One of the widely used methods of early detection of damages is the vibration analysis of the structure. Hence, it is of vital importance to detect and monitor any changes in the natural frequencies of the structure. From this standpoint, in this study we experimentally investigated the effect of fatigue crack propagation on beams produced from 4140 steel, of the natural frequency of the beam. A crack was opened on the $8{\times}16{\times}500mm$ beam using a 3 mm long and 0.25 mm wide wire erosion. The beam, then, underwent 3 point bending tests at 10 Hz with a dynamic fatigue device and its natural frequencies were measured in scheduled intervals and any changes taking place on the natural frequencies of the beam were measured. This data allowed us to identify and measure the crack occurring on the beam subjected to dynamic loading, during the propagation phase. This method produced experimental data. The experimental data showed that the natural frequency of the beam decreased with the propagation of the fatigue crack on the beam.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.20 no.4
• /
• pp.15-24
• /
• 2019

The optimum solutions of MOSCOS antenna arrangement were studied to solve the EMI between it and EWT mounted on an MTB. Two candidates of optimal place for MOSCOS antenna were determined by using a fishbone diagram to determine seven reasons based on 4M1E, to identify the design factors on Friis equations, and to analyze the case study of EMI related to MOSCOS. MOSCOS antenna was rearranged by the final optimal position, which was selected by measuring the Power Spectral Density (PSD) at two locations, and the proposed improvement was tested on board to determine its efficiency.

• Journal of Preventive Medicine and Public Health
• /
• v.52 no.5
• /
• pp.281-291
• /
• 2019

Objectives: The validity of instruments measuring socioeconomic position (SEP) has been a major area of concern in research on cardiovascular health disparities. The purpose of this systematic review is to identify the current status of the methods used to measure SEP in research on cardiovascular health disparities in Korea and to provide directions for future research. Methods: Relevant articles were obtained through electronic database searches with manual searches of reference lists and no restriction on the date of publication. SEP indicators were categorized into compositional, contextual, composite, and life-course measures. Results: Forty-eight studies published from 2003 to 2018 satisfied the review criteria. Studies utilizing compositional measures mainly relied on a limited number of SEP parameters. In addition, these measures hardly addressed the time-varying and subjective features of SEP. Finding valid contextual measures at the organizational, community, and societal levels that are appropriate to Korea's context remains a challenge, and these are rarely modeled simultaneously. Studies have rarely focused on composite and life-course measures. Conclusions: Future studies should develop and utilize valid compositional and contextual measures and appraise social patterns that vary across time, place, and culture using such measures. Studies should also consider multilevel influences, adding a focus on the interactions between different levels of intertwined SEP factors to advance the design of research. More attention should be given to composite and life-course measures.

• Journal of Preventive Medicine and Public Health
• /
• v.52 no.3
• /
• pp.154-160
• /
• 2019

Objectives: Stillbirth is a common adverse pregnancy outcome that represents a distressing and traumatic event for women and their partners. The aim of this study was to identify factors associated with stillbirth in ever-pregnant women in Nepal. Methods: This study utilized the individual women's dataset from the Nepal Demographic and Health Survey, conducted in 2016. The dependent variable of interest was whether women had at least 1 stillbirth during their lifetime. The associations between independent variables and the dependent variable of the study were analyzed using a multiple logistic regression model. Results: Among 8918 ever-pregnant women aged 15-49 years, 488 had experienced at least 1 stillbirth during their lifetime, representing 5.5% of the total. After adjusting each factor for the confounding effects of other factors, maternal age, maternal education, place of residence, and sub-region remained significantly associated with having experienced stillbirth. Conclusions: Stillbirth continues to be a major problem among women, especially those with higher maternal age, those who are illiterate, and residents of certain geographical regions. To minimize stillbirth in Nepal, plans and policies should be focused on women with low education levels and residents of rural areas, especially in the western mountain and far-western hill regions.

• Journal of the Korea Institute of Building Construction
• /
• v.20 no.6
• /
• pp.577-584
• /
• 2020

Construction automation and robotics have been widely adopted in the construction industry as a promising solution to such issues like a shortage of skilled labor and the difficulties workers face in harsh working environments. The analysis of the knowledge structure and its evolution from the existing articles helps identify essential knowledge elements and possible future research directions. This study attempts to (1) construct keyword networks from the papers published in the International Symposium on Automation and Robotics in Construction (ISARC), (2) investigate how keywords and keyword communities are associated with each other, and (3) examine the changes in the crucial keywords over time. Through cluster analysis, 79 keywords were categorized into four groups (BIM, Building construction, Sensing, and GPS as representative keywords) with similar structural positions. Research trends show that research themes related to Infrastructure, Construction equipment, and 3D have consistently received a large amount of attention, regardless of geographical region. Research on as-built status model utilization through BIM and Laser scanning and improving Energy performance is taking place more frequently. In contrast, research studies related to problem-solving based on Neural networks are not as common as previously. This study provides useful insights into the construction automation field, at both the macro and micro levels.

• Journal of architectural history
• /
• v.30 no.4
• /
• pp.79-90
• /
• 2021

Since its construction in the late 14th century, Hanyangdoseong had been carried out three major repairs and reconstructions during the 500 years of the Joseon Dynasty. In addition to the large-scale construction, small-scale construction continued until King Gojong era. In particular, in the 18th century, systematic construction management was implemented by the craftsmen and the military participated in the renovation of Hanyangdoseong in earnest, and the construction methods also developed rapidly. In the early 18th century, new construction techniques were attempted in various sections of the reconstruction work, and gradually became a common technology for repairing Hanyangdoseong in the late 18th century. The purpose of this study is to examine the characteristics and period of changes in the 18th century's construction technique, when the rapid development of Hanyangdoseong took place. To this end, the excavation results related to Hanyangdoseong, the remaining city wall, and the inscribed stones were used to identify and demonstrate the characteristics and change of the construction method.

• Korea Trade Review
• /
• v.44 no.5
• /
• pp.93-106
• /
• 2019

The purpose of the study is to investigate whether monetary and non-monetary incentives paid to exporters influence the level of compliance and tendency to behave opportunistically. As one of the most common ways to export one's products overseas is to establish relationships with foreign agents, numerous research has aimed to identify types of incentives to motivate foreign agents to bring the most efficient outcomes. Stemming from previous studies, this research hypothesizes that the type of incentives affects exporter's level of compliance, and tendency to act opportunistically which determine the level of exporter's satisfaction on foreign agency role performance. Data was collected from 196 Korean exporters, and the findings suggest that exporters should actively engage in providing non-monetary incentives to their agents to motivate importers to comply with exporter's rules. Conversely, agents tend to act more opportunistically when they receive monetary incentives only. These phenomena lead to the conclusions that the satisfaction level of foreign agency role performance is improved when non-monetary incentives are actively in place, and at the same time, foreign agent's level of compliance and opportunism play mediating roles.

• Nuclear Engineering and Technology
• /
• v.53 no.6
• /
• pp.2038-2045
• /
• 2021

The main objective of this work is to propose a reliable routine standard operation procedures (SOP) for structural health monitoring and diagnosis of nuclear power plants (NPPs). At present, NPPs have monitoring systems that can be used to obtain the quantitative health record of containment (CTMT) buildings through system identification technology. However, because the measurement signals are often interfered with by noise, the identification results may introduce erroneous conclusions if the measured data is directly adopted. Therefore, this paper recommends the SOP for signal screening and the required identification procedures to identify the dynamic characteristics of the CTMT of NPPs. In the SOP, three recommend methods are proposed including the Recursive Least Squares (RLS), the Observer Kalman Filter Identification/Eigensystem Realization Algorithm (OKID/ERA), and the Frequency Response Function (FRF). The identification results can be verified by comparing the results of different methods. Finally, a preliminary CTMT healthy record can be established based on the limited number of earthquake records. It can be served as the quantitative reference to expedite the restart procedure. If the fundamental frequency of the CTMT drops significantly after the Operating Basis Earthquake and Safe Shutdown Earthquake (OBE/SSE), it means that the restart actions suggested by the regulatory guide should be taken in place immediately.

• Korean Journal of Acupuncture
• /
• v.38 no.4
• /
• pp.290-307
• /
• 2021

Objectives : Perceptual experiences have a causal relationship with reality. If there exists something corresponding to acupoints, there should be perceptual experiences for that something. The purpose of this study is to identify and to analyze the perceptual experiences for acupoints within 『LingShu·BenShu』. Methods : First, we briefly propose a perceptual anatomy in order to describe the perceived human body parts, and their perceived directions and places. Second, we analyze the ways of identifying acupoints in the original text of 『LingShu·BenShu』. Results : From 『LingShu·BenShu』, the procedures of identifying total 64 acupoints were recognized. It was clarified that they are by way of visual and haptic explorations in body regions and partial regions. Conclusions : Perceptual explorations for acupoints follow three major principles: of gradual narrowing down, of determination of direction or place, of relative distance. At the final stages, categories of form and location are encountered by observers. The forms have either concavities or convexities. They are determinate indicators of where acupoints are, while the locations are indetermanate. Haptic forms of acupoints are newly discovered from textual analysis with perceptual anatomy. These properties will shed new light both on study of acupoints and on study of meridians.

• Journal of Korean Academy of Rural Health Nursing
• /
• v.17 no.1
• /
• pp.23-33
• /
• 2022

Purpose: This study was conducted to identify the effects of an integrated health improvement program for the elderly based on primary health care posts during the COVID-19 pandemic. Methods: A single group pretest-posttest design (n=16) was employed to evaluate an integrated health improvement program that took place twice a week for 11 weeks. The program was conducted in a small group of no more than 10 people in compliance with the guidelines to prevent COVID-19 infection. The program consisted of various contents such as making letters using blocks, health education, and talking about one's memories. The data were analyzed using the Wilcoxon signed rank test. Results: Following the program, social support (Z=-3.50, p<.001) and quality of life of the elderly (Z=-3.74, p<.001) were significantly improved among depression, social support and quality of life. Conclusion: The integrated health improvement program based on primary health care posts, considered in this study, was useful to improve the social support and quality of life of the elderly in the community, and needs to be applied to a larger number of elderly people throughout the community.