• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.22 no.3
• /
• pp.777-783
• /
• 2021

Aircraft are affected by various vibrations during maneuvering. These vibrations may have a fatal effect on the survival of aircraft in some cases, so the safety of components applied to the aircraft should be proven against various vibrations through random vibration analysis. In this study, the structural robustness of an external fuel tank and pylon for military aircraft was evaluated under random vibration conditions using commercial software, MSC Random. In the random vibration analysis, a frequency response analysis was performed by imposing a unit load on the boundary condition point, and then excitation was performed with a PSD profile. In this process, the required mode data was extracted through a modal analysis method. In addition, the random vibration profile specified in the US Defense Environment Standard was applied as random vibration conditions, and the PSD profile given in units of G's was converted into units of gravitational acceleration. As a result of the numerical analysis, we evaluated the structural robustness of the external fuel tank and pylon by identifying the safety margins of beam elements, shell elements, and solid elements in a numerical model for random vibration in the x, y, and z directions.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.22 no.2
• /
• pp.336-344
• /
• 2021

The purpose of this study was to identify the self-awareness of smartphone dependence among undergraduate students and their response to the same. The data was drawn from a survey on smartphone overdependence conducted by the Ministry of Science and information and communications technology (ICT) and the National Information Society Agency in 2017. The responses of 1,735 undergraduate students were analyzed by frequency, percentage, mean, standard deviation, minimum-maximum value, ��2-test, independent t-test, Pearson's correlation coefficient, and stepwise multiple regression analysis. The results indicated that 22.3% of participants were at risk of smartphone dependence, and 63.6% of them were unaware of their dependence on smartphones. The perception of smartphone dependence was significantly associated with a higher risk of smartphone dependence (��=.35, p=.000) and the increasing use of applications such as games (��=.19, p=.000), television/video (��=.11, p=.000), and learning (��=.11, p=.000). Of the participants with dependence awareness, only a few knew about the existence of centers to prevent smartphone and internet dependence. Moreover, they rarely utilized these centers. However, the participants felt the need for more counseling agencies (26.8%), programs for dealing with oneself (23.2%), information about smartphone dependence (14.9%), and help to overcome dependence (10.9%). These findings show the need to establish public services so that students can easily access correct information on smartphone dependence and address this problem.

• Atmosphere
• /
• v.30 no.4
• /
• pp.377-390
• /
• 2020

Not only emissions, but also atmospheric circulation is a key factor that affects local particulate matters (PM) concentrations in Korea through ventilation effects and transboundary transports. As part of the atmospheric circulation, air stagnation especially adversely affects local air quality due to weak ventilation. This study investigates the large-scale circulation related to air stagnation over Korea during winter and projects the climate change impacts on atmospheric patterns, using observed PM data, reanalysis and regional climate projections from HadGEM3-RA with Modified Korea Particulate matter Index. Results show that the stagnation affects the PM concentration, accompanied by pressure ridge at upper troposphere and weaken zonal pressure gradient at lower troposphere. Downscaling using HadGEM3-RA is found to yield Added-Value in the simulated low tropospheric winds. For projection of future stagnation, SSP5-8.5 and SSP1-2.6 (high and low emission) scenarios are used here. It has been found that the stagnation condition occurs more frequently by 11% under SSP5-8.5 and by 5% under SSP1-2.6 than in present-day climate and is most affected by changes in surface wind speed. The increase in the stagnation conditions is related to anticyclonic circulation anomaly at upper troposphere and weaken meridional pressure gradient at lower troposphere. Considering that the present East Asian winter monsoon is mainly affected by change in zonal pressure gradient, it is worth paying attention to this change in the meridional gradient. Our results suggest that future warming condition increase the frequency of air stagnation over Korea during winter with response of atmospheric circulation and its nonlinearity.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.24 no.6
• /
• pp.34-41
• /
• 2020

In recent years, magnitude and frequency of earthquakes have increased in Korea. Damage to a bridge, which is one of the main infrastructures, can directly lead to considerable loss of human lives. Therefore, engineers need to evaluate the seismic fragility of the structure and prepare for the possible seismic damage. In particular, the number of aging bridges over 30 years of service increases, and thus the seismic analysis and fragility requires accounting for the aging and retrofit effects on the bridge. In this study, the nonlinear static and dynamic analyses were performed to evaluate the effects of the aging and FRP retrofit on a PSC bridge. The aging and FRP retrofit were applied to piers that dominate the response of the bridge during earthquakes. The maximum displacement of the bridge increased due to the aging of the pier but decreased when FRP retrofit applied to the aged pier. In addition, seismic fragility analysis was performed to evaluate the seismic behavior of the bridge combined with the seismic performance of the pier. Compared with the aged bridge, the FRP retrofit bridge showed a decrease in the seismic fragility in all levels of damage. The reduction of the seismic fragility in the FRP bridge was prominent as the value of PGA and level of damage increased.

• Journal of the Korean BIBLIA Society for library and Information Science
• /
• v.32 no.4
• /
• pp.161-188
• /
• 2021

Libraries are experiencing numerous modifications to multifunctional spaces in response to the declaration of WHO pandemic. Most libraries throughout the globe have reported their closures, including national libraries in every country, and most established facing services have been transformed to untact services. However, the breadth of the service varies by local autonomous entity and library, making it difficult for librarians to act according to their conviction, and also users are feeling inconvenienced. As a result, this study used a user perception survey to determine the extent of non-face-to-face services in the library and to suggest the direction of operation of non-face-to-face services in a pandemic condition. To that purpose, beginning February 12, 2020, an online survey of library customers in 37 public libraries was performed for about three weeks, and the 117 replies were examined using the SPSS statistics tool to perform frequency analysis, regression analysis, correlation analysis, and reliability analysis. By the survey and data survey results, it was recommended that library services be re-established in the direction of non-face-to-face library service operation, that library non-face-to-face services be expanded, that user education be conducted, that non-face-to-face services be promoted, and that user opinions be collected.

• The Journal of the Korea Contents Association
• /
• v.22 no.7
• /
• pp.81-88
• /
• 2022

This study is to investigate the perception of domestic appraisers about the possibility of using artificial intelligence (AI) and related risks from the use of AI in the appraisal industry. We conducted a mobile survey of evaluators from February 10 to 18, 2022. We collected survey data from 193 respondents. Frequency analysis and multiple response analysis were performed for basic analysis. When AI is used in the appraisal industry, factor analysis was used to analyze various types of risks. Although appraisers have a positive perception of AI introduction in the appraisal industry, they considered collateral, consulting, and taxation, mainly in areas where AI is likely to be used and replaced, mainly negative effects related to job losses and job replacement. They were more aware of the alternative risks caused by AI in the field of human labor. I was very aware of responsibilities, privacy and security, and the risk of technical errors. However, fairness, transparency, and reliability risks were generally perceived as low risk issues. Existing studies have mainly studied analysis methods that apply AI to mass evaluation models, but this study focused on the use and risk of AI. Understanding industry experts' perceptions of AI utilization will help minimize potential risks when AI is introduced on a large scale.

• Journal of Korea Entertainment Industry Association
• /
• v.14 no.3
• /
• pp.375-382
• /
• 2020

The purpose of this study was to examine the awareness and performance of hand washing in some health-related college students and to provide basic data on the management of hand washing through the difference and correlation between awareness and performance. This study collected data from 367 questionnaires excluding non-response and unfaithful responses from health-related college students in nursing, physiotherapy and occupational therapy. The survey tool was a Likert 5-point scale self-filled questionnaire that examined general characteristics, hand washing awareness and performance. The general characteristics of the subjects were calculated by frequency analysis, and one-way ANOVA, awareness and performance were analyzed by Pearson's correlation. There was a significant difference in the awareness of hand washing in some health-related college students in the presence or absence of infection education and in all areas except gender. According to the characteristics of the health department, the awareness and performance of hand washing showed a significant difference in the order of physical therapy, occupational therapy, and nursing. There was a significant difference in hand washing awareness in grade characteristics and no significant difference in performance. There was a high correlation between awareness and performance of hand washing.

• Journal of Convergence for Information Technology
• /
• v.12 no.5
• /
• pp.183-193
• /
• 2022

The purpose of this study is to analyze the effect of black consumer behavior perception on the anger expression and turnover intention of beauty workers. For data collection, the final 392 copies were used by distributing questionnaires to 400 people for three months from November 1, 2021 to January 31, 2022, centering on beauty service workers in Seoul, Gyeonggi, and Incheon. For data analysis, SPSS 25.0 program was used. Frequency analysis was performed to identify demographic characteristics, and factor analysis and reliability analysis were performed to understand the validity of the measurement tool. Correlation analysis, A regression analysis was performed. As a result of the analysis, the transient and deterrence of black consumers had a positive (+) effect on anger expression, anger suppression, and turnover intention, and anger expression and anger control had a positive (+) effect on turnover intention. Therefore, it is necessary to raise excessive problems of black consumers or eradicate forced services, and it is believed that proper customer response methods and programs for stress relief should be provided by members.

• The Journal of Internal Korean Medicine
• /
• v.43 no.4
• /
• pp.625-642
• /
• 2022

Objectives: Postoperative ileus (POI) is a common impairment of gastrointestinal motility and causes a delay in postoperative recovery, as well as an increased length of hospital stay, but no single strategy has a significant recuperative effect on POI. Studies of traditional Korean medicine (TKM) have reported improvements in bowel function after surgery. The aim of this systematic review was to assess the effectiveness of TKM on postoperative ileus in gastric cancer patients. Methods: We used six databases to search for studies published from January 1, 2007, until May 11, 2022. The included studies were those reporting gastric cancer patients who received TKM treatment after gastrectomy through indicators related to POI. Results: The search identified 27 RCTs that used herbal medicine (Daegeonjung-tang and Gami-leejoongtang), herbal medicine combined with acupuncture (Sama-tang, Gumiseunggi-tang, Daeseunggi-tang, and Insam-tang), acupuncture, acupuncture and moxibustion, electroacupuncture, warm needling, transcutaneous electroacupuncture (TEA), low-frequency electrical acupoint stimulation (LEAS), moxibustion, auricular acupressure, and ST-36 acupoint injection with neostigmine as treatments for POI. The time to first flatus was shortened by herbal medicine combined with warm needling (Sama-tang, Gumiseunggi-tang, Daeseunggi-tang, and Insam-tang), acupuncture, electroacupuncture, warm needling, TEA, moxibustion, auricular acupressure, and ST-36 acupoint injection with neostigmine (p<0.00001). The time to the first defecation decreased significantly in response to the herbal medicine combined with warm needling (Sama-tang, Gumiseunggi-tang, Daeseunggi-tang, and Insam-tang), acupuncture, electroacupuncture, warm needling, TEA, moxibustion, auricular acupressure, and ST-36 acupoint injection with neostigmine (p<0.00001). No serious adverse events occurred. Conclusions: TKM could be a promising option for preventing and resolving POI in gastric cancer patients after gastrectomy.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.25 no.6
• /
• pp.154-160
• /
• 2021

Recently, there have been increasing construction works carried out in urban centers, which are inducing frequent artificial vibration in the vicinity of existing structures due to such construction works. moreover, in case of industrial estates, vibration is induced due to operation of machines in the surrounding areas, thereby causing problems. meanwhile, in case of ordinary concrete that compose structure has low level of damping capability for vibration. accordingly, there are difficulties in blocking a wide range of vibrations delivered to the structures from outside including not only vibrations generated in the structures themselves but also ground vibration. recently, numerous studies are being carried out actively on high-damping system that markedly enhanced the damping performances of structures by utilizing polymer concrete in order to block the vibrations delivered to the structures through ground. therefore, this study compared the performances of polymer concrete with those of ordinary concrete, polyurethane pad and foamed rubber pad in order to review its performances in reducing ground vibration. for this purpose, review of FRF and vibration acceleration as dynamic characteristics was made. after comparative verification on the dynamic characteristics is made when polymer concrete and other aforementioned materials are applied to underground structures, the possibility of application of polymer concrete to structures is reviewed.