• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.29 no.2D
• /
• pp.245-253
• /
• 2009

Road facility is the most fundamental infrastructure for traffic and various information for smooth traffic is included in road surfaces. Various information included in road surfaces should be often removed and reinstalled by partial damage and aging. In addition, the existing road surface information should be removed in order to mark new information as traffic information changes. The existing road surface removal method suing grinders and torches had problems such as dangerous working equipment and workers' direct exposure to cars. In addition, although water-jet system using super high-pressure water was used to remove road surface in order of improvement of traditional method, there are another problems such as limitations according to water-tanks and water frost on the road surfaces after work. Therefore, this study analyzes and suggests systems to develop prototype after analyzing dry ice blaster in order to improve the current road surface removal methods. In addition, the study analyzes the possibility of introduction of dry ice blaster through a test for proposing an automatized equipment for new road surface mark removal considering environment and work efficiency, and compare traditional method with introduced dry ice blaster for operating cost.

• 한국노년학
• /
• v.31 no.3
• /
• pp.733-749
• /
• 2011

The purpose of this research are as follows. The first is to investigate the mediating effect of interpersonal skill on the relationship between the ability to use Internet and social activity among the 50's and 60's. The second is to compare 60's latent mean of core variables with 50's ones in terms of information gap. The data was Seoul welfare panel data made by Seoul welfare foundation in 2008 and the total subject was 941(50's=644, 60's=297). When it comes to the research methods, structured equation analysis for verifying the mediating effect and latent mean analysis for comparing the two groups were practiced. The results of this research are as follows. First of all, interpersonal skill did function as partial mediator. Second, according to the latent mean analysis, the group of 50's showed a more higher level of the ability to use Internet. On the other hand, the group of 60's revealed a more active social participation. In conclusion, Information educational programs should focus on Internet communication skill for enhancing social activities of the elderly and consider the differentiations among the elder generations.

• The Journal of the Korea Contents Association
• /
• v.22 no.8
• /
• pp.607-618
• /
• 2022

The purpose of this study was to identify the effect of family resilience on willingness for self-sufficiency in self-sufficiency program participants and to verify the mediating effect of mental health in the relationship. The survey subjects were 283 participants from a local self-support center in Gangwon-do. As for the analysis method, descriptive statistics and difference verification were performed. Also, hierarchical regression analysis and mediating effect method were performed to verify the research model. First, as a result of the difference test, the level of self-support was higher when there was a caring family. The level of family resilience was higher in those who were in their 40s and 50s than in their 30s or less, married than unmarried, had normal or excellent health conditions than deplorable health conditions, and had a caring family. Mental health quality was higher in very healthy people rather than in people who had poor health. Also, people with no dept had a higher mental health quality. Second, as a result of analyzing the relationship of influence on self-support, the higher the age, the more caring families, the higher the level of family resilience and mental health, the higher the self-sufficiency. Third, as a result of the mediating effect analysis, mental health had a partial mediating effect between family resilience and willingness for self-sufficiency. Therefore, we discussed the implications for improving family resilience and mental health as a factor in improving the level of self-sufficiency in self-sufficiency program participants.

• 한국노년학
• /
• v.39 no.1
• /
• pp.73-92
• /
• 2019

The purpose of this study is to verify the influence of volunteering on the sense of community and the community capacity, and the mediating effect of the sense of community on the relationship between volunteering variables(the period and satisfaction of volunteering) and the community capacity as well. Study population is 1,416 elderly volunteers who participated in the government-sponsored elderly volunteer program for prevention of depression and suicide in 2016. The results show that the experience of volunteering plays an important role in improving the sense of community and the community capacity among the older participants. As for the analysis of the mediating effect, the sense of community has a perfect mediating effect between the period of volunteering and the community capacity, and a partial mediating effect between volunteering satisfaction and the community capacity. Based on these findings, the theoretical and practical implications were discussed.

• Journal of the Institute of Convergence Signal Processing
• /
• v.24 no.2
• /
• pp.119-125
• /
• 2023

In this study, we photograph driving obstacle objects such as crosswalks, side spheres, manholes, braille blocks, partial ramps, temporary safety barriers, stairs, and inclined curb that hinder or cause inconvenience to the movement of the vulnerable using electric mobility aids. We develop an optimal AI model that classifies photographed objects and automatically recognizes them, and implement an algorithm that can efficiently determine obstacles in front of electric mobility aids. In order to enable object detection to be AI learning with high probability, the labeling form is labeled as a polygon form when building a dataset. It was developed using a Mask R-CNN model in Detectron2 framework that can detect objects labeled in the form of polygons. Image acquisition was conducted by dividing it into two groups: the general public and the transportation weak, and image information obtained in two areas of the test bed was secured. As for the parameter setting of the Mask R-CNN learning result, it was confirmed that the model learned with IMAGES_PER_BATCH: 2, BASE_LEARNING_RATE 0.001, MAX_ITERATION: 10,000 showed the highest performance at 68.532, so that the user can quickly and accurately recognize driving risks and obstacles.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.27 no.5
• /
• pp.120-129
• /
• 2023

Hanger cable tension is a major response that can determine the integrity and safety of suspension bridges. In general, the vibration method is used to estimate hanger cable tension on operational suspension bridges. It measures natural frequencies from hanger cables and indirectly estimates tension using the geometry conditions of the hanger cables. This study estimated the hanger cable tension of the Palyeong Bridge using a vision-based system. The vision-based system used digital camcorders and tripods considering the convenience and economic efficiency of measurement. Measuring the natural frequencies for high-order modes required for the vibration method is difficult because the hanger cable response measured using the vision-based system is displacement-based. Therefore, this study proposed a back analysis technique for estimating tension using the natural frequencies of low-order modes. Optimization for the back analysis technique was performed by defining the difference between the natural frequencies of hanger cables measured in the field and those calculated using finite element analysis as the objective function. The direct search method that does not require the partial derivatives of the objective function was applied as the optimization method. The reliability and accuracy of the back analysis technique were verified by comparing the tension calculated using the method with that estimated using the vibration method. Tension was accurately estimated using the natural frequencies of low-order modes by applying the back analysis technique.

• Journal of the Korean Geosynthetics Society
• /
• v.23 no.2
• /
• pp.43-52
• /
• 2024

Recent abnormal climate conditions have increased the risk of slope collapses, which frequently result in significant loss of life and property due to the absence of early prediction and warning dissemination. In this paper, we develop a slope condition analysis system using IoT sensors and AI-based camera to assess the condition of slopes. To develop the system, we conducted hardware and firmware design for measurement sensors considering the ground conditions of slopes, designed AI-based image analysis algorithms, and developed prediction and warning solutions and systems. We aimed to minimize errors in sensor data through the integration of IoT sensor data and AI camera image analysis, ultimately enhancing the reliability of the data. Additionally, we evaluated the accuracy (reliability) by applying it to actual slopes. As a result, sensor measurement errors were maintained within 0.1°, and the data transmission rate exceeded 95%. Moreover, the AI-based image analysis system demonstrated nighttime partial recognition rates of over 99%, indicating excellent performance even in low-light conditions. Through this research, it is anticipated that the analysis of slope conditions and smart maintenance management in various fields of Social Overhead Capital (SOC) facilities can be applied.

• Information Systems Review
• /
• v.20 no.2
• /
• pp.21-37
• /
• 2018

Under ubiquitous work environment, innovative changes occur in work process with ICT. The work process for collaboration through mobile devices and network should be investigated. The research model consists of two major antecedents: autonomy and interdependence as a task characteristic and job satisfaction as ultimate consequence followed by work design theory. To elaborate work design theory, smartwork application (app) use, communication extent, and work-life balance were reviewed from the literature. Data were collected from three ICT firms, which adopted certain smartwork app, and a partial least squares analysis was made on 175 data points. The analysis results show that task interdependence exerts a statistically significant effect on the level of smartwork app usage. Communication extent directly affects job satisfaction and work-life balance. The remarkable point is that smartwork app usage does not affect employees' work-life balance; the former can only affect the latter indirectly by increasing communication extent. This study attempts to explain the organizational impact by considering smartwork app and the effects simultaneously. We proposed and empirically tested the extended work design theory including information technology and its environment. Based on the results, other theoretical and practical contributions are discussed at the end with limitations and further studies.

• Korean Journal of Psychosomatic Medicine
• /
• v.19 no.2
• /
• pp.92-100
• /
• 2011

Objectives：We developed a Korean version of the Brief Measure of Worry Severity(BMWS), and examined its reliability, validity, and factor structures. We also explored the associations of pathological worry with depression and anxiety. Methods：Three hundreds fifty-two subjects including community population and college students completed the BMWS, and 27 subjects repeated the scale three weeks later. Reliability was assessed by Cronbach's coefficient ${\alpha}$ and test-retest correlation. The external validity was examined by the correlation of the BMWS score with the scores of Beck Depression Inventory(BDI), Patient Health questionnaire-2(PHQ-2), State Anxiety Inven-tory(SAI), and Trait Anxiety Inventory(TAI). And principal component analysis was performed to evaluate the construct validity. The associations of pathological worry with depression and anxiety were explored using partial correlation analysis. Results：Cronbach's coefficient ${\alpha}$ for the BMWS was 0.904 and test-retest correlation was 0.56(P<0.01). The Spearman correlation coefficients of the BMWS score with the scores of BDI, PHQ-2, SAI, and TAI were 0.60(P<0.01), 0.42(P<0.01), 0.36(P<0.01), and 0.59(P<0.01), respectively. The BMWS showed unifactorial construct. When controlling for TAI score, the correlation coefficient between the BMWS score and the BDI score was 0.357(P<0.01), and when controlling for BDI score the correlation coefficient between the BMWS score and the TAI score was 0.446(P<0.01). Conclusion：The Korean version of the BMWS was found to be a reliable and valid questionnaire for measuring pathological worry. And we could identify the associations of the pathological worry with depression as well as anxiety.

• Journal of the Korea Concrete Institute
• /
• v.19 no.1
• /
• pp.121-130
• /
• 2007

To investigate the enhancement in strength and deformation capacities of concrete confined by FRP composites, tests under axial loads were carried out on three groups of thirty six short columns in circular section with diverse GFRP confining reinforcement. The major test variables considered include fiber content or orientation, wrap or tube type by varying the end loading condition, and continuous or discontinuous confinement depending on the presence of vortical spices between its two halves. The circumferential FRP strains at failure for different types of confinements were also investigated with emphasis. Various analytical models capable of predicting the ultimate strength and strain of the confined concrete were examined by comparing to observed results. Tests results showed that FRP wraps or tubes provide the substantial increase in strength and deformation, while partial wraps comprising the vertical discontinuities fail in an explosive manner with less increase in strength, particularly in deformation. A bilinear stress-strain response was observed throughout all tests with some variations of strain hardening. The failure hoop strains measured on the FRP surface were less than those obtained from the tensile coupons in all tests with a high degree of variation. In overall, existing predictive equations overestimated ultimate strengths and strains observed in present tests, with a much larger scatter related to the latter. For more accuracy, two simple design- oriented equations correlated with present tests are proposed. The strength equation was derived using the Mohr-Coulomb failure criterion, whereas the strain equation was based on entirely fitting of test data including the unconfined concrete strength as one of governing factors.