• Tunnel and Underground Space
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• v.23 no.5
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• pp.392-400
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• 2013

Joint sets should be considered as an influence factor, when location of subsidence zone by stopes is predicted. And the mechanical properties and distribution patterns of joint set above stopes may be affecting subsidence occurrence. In this study, therefore, the orientation of joint sets is reanalyzed with the data from the previous research on prediction of defining the subsidence zone. From a correlated analysis, the influence of major joint set($J_1$) on subsidence location was analyzed by comparing the angle of assumption with the angle of major joint set($J_1$).

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.10B
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• pp.619-629
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• 2005

In this paper, we propose energy-aware routing schemes which are simple enough to be applicable to the wireless sensor networks. The one hop upstream no de in direction of the base-station is determined in four different ways based on the energy information of neighboring nodes, which are obtainable via the process of self-organization of the network. The fair distribution of the energy consumption over all the possible routes to the base-station is one of the design objectives. Also, an alternate route search mechanism is proposed to cope with the situation in which no routing information is available due to lack of remaining energy of the neighboring nodes. The mechanism turns out to be a supplementary scheme to improve the energy efficiency. Lots of simulations are performed to examine the performance metrics such as the energy efficiency, throughput, network lifetime, and the transmission latency of the proposed schemes. Simulation results show the feasibility of the simple routing schemes for the sensor networks.

• Korean Journal of Construction Engineering and Management
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• v.19 no.4
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• pp.43-51
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• 2018

As the inventory of aged apartments is expected to increase explosively, the importance of maintenance to improve the durability of concrete facilities is increasing. Concrete compressive strength is a representative index of durability of concrete facilities, and is an important item in the precision safety diagnosis for facility maintenance. However, existing methods for measuring the concrete compressive strength and determining the maintenance of concrete facilities have limitations such as facility safety problem, high cost problem, and low reliability problem. In this study, we proposed a model that can predict the concrete compressive strength through images by using deep convolution neural network technique. Learning, validation and testing were conducted by applying the concrete compressive strength dataset constructed through the concrete specimen which is produced in the laboratory environment. As a result, it was found that the concrete compressive strength could be learned by using the images, and the validity of the proposed model was confirmed.

• Solar Energy
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• v.20 no.1
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• pp.45-54
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• 2000

Five direct/diffuse decomposition models were validated using the eight years data set of direct normal beam insolation measured in Seoul. The comparison has been performed In terms of the widely used statistical indicators such as MBE, RMSE, CV(RMSE), t-Statistic and Degree of Agreement. Result indicates that most of the correlations exhibit a tendency to underestimate the direct normal beam insolation except Bouguer's model. Most of big discrepancies between the measured and the predicted values was mainly shown in near the sunrising and the sunset period. Even though the investigated five models showed fairly large disagreement for the measured values by 34%$\sim$48% of CV(RMSE), Udagawa's correlation which includes the effect of solar altitude variation appears to performs always better in every statistical error tests.

• Journal of the Korean Association of Geographic Information Studies
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• v.25 no.2
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• pp.48-58
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• 2022

This study tried to assess the applicability of a hand-held LiDAR for measuring the geometric structures of forest trees including diameters at a breast height(DBH) and tree height(H). A traditional method using tapelines was conducted to analyze the accuracy of the LiDAR instrument in the Taebaeksan national park in South Korea. Four statistical indices which are bias, root mean square error, mean absolute error, and correlation coefficient were employed to compare the measurements by the LiDAR instrument and traditional method. The DBHs from the LiDAR were very similar to those from the traditional method. And it indicated that the LiDAR is sufficient to be a alternative of a traditional method. However, there was a limitation in assessing the accuracy of LiDAR for measuring tree height by comparing the measurements by observer's eyes since they included different error sources. Further study is needed to assess the accuracy of LiDAR instrument for tree height through more reliable measurements.

• Industry Promotion Research
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• v.8 no.3
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• pp.181-199
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• 2023

E-commerce is gradually upgrading from traditional text and image formats to short video and livestreaming formats. Livestreaming e-commerce enriches the content and forms of information dissemination and product display, enhances the consumer's shopping experience, and gradually becomes the mainstream new consumer scene. However, there are many negative phenomena in the development of livestreaming e-commerce, such as false propaganda, counterfeit goods, and various negative events, which seriously affect the level of consumer trust in livestreaming e-commerce. Trust is the core competitive factor of livestreaming e-commerce. Based on previous research on trust theory and combined with the characteristic elements of "people, goods, and scenes" of livestreaming e-commerce, this article constructs a trust model for livestreaming e-commerce, proposes hypotheses, and proves through empirical research that factors such as store characteristics, livestream host characteristics, brand image, product information, platform reputation, livestreaming situation, and trust tendency have a significant positive impact on consumer trust. Based on the research conclusions, this article provides insights and management suggestions, such as emphasizing the construction of store characteristic indicators, creating desirable livestream host characteristics, focusing on product brand building and selection, maintaining the display of product information, selecting suitable livestreaming platforms, and creating rich content for livestreaming situations.

• Journal of Preventive Medicine and Public Health
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• v.24 no.1 s.33
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• pp.57-69
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• 1991

This study examined the cross-sectional association of central body fat distribution with hypertension as well as the superiority of medial calf skinfold measured as peripheral fat distribution over the conventional triceps skinfold using 450 Korean Navy divers selected by authors' convenience in 1990. Their mean age was 27.9 and range of it was 19-51. The centrally located body fat was approximated by subscapular skinfold and peripherally located fat by triceps and medial calf skinfolds. Four indices were constructed from these skinfold measures to reflect central versus peripheral fat distribution pattern : 2 ratios and 2 differences. After controlling age and overall obesity (body mass index), prevalance odds ratios of the 2/4, 3/4, 4/4 quartiles of subscapular skinfold comparing with lowest 1/4 quartile were 2.05(95% confidence interval, CI 1.18-3.59), 2.02(95% CI 1.06-3.86), 4.00 (95% CI 1.99-8.06) respectively. The difference of subscapular and medial calf skinfolds was associated with hypertension (odds ratio 2.45, 95% CI 1.28-4.68 comparing highest with lowest quartiles). Triceps and medial calf skinfolds alone did not show any odds ratio not including unity. The adjusted odds ratios were generally reduced in small magnitude compared with crude odds ratios not adjusted for age and overall obesity. The medial calf skinfold appeared to be more representative of peripheral body fat distribution than triceps skinfold. These findings suggest that central fat distribution rather than peripheral distribution is associated with hypertension independent of age and overall level of obesity and medial calf skinfold may replace conventional triceps skinfold in predicting peripheral distribution of body fat.

• The Journal of Society for e-Business Studies
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• v.11 no.2
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• pp.49-69
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• 2006

The virtual community has been recognized as an effective marketing tool and has been an important motive of using internet to Internet users, but very few attempts have been done for the development of virtual community success. Although many studies have been made on influencing factors of virtual community success, the comprehensive studies have never been done so far. Therefore, this study focused on developing the comprehensive model and verifying empirically. This study proposed five influencing factors(Virtual Community Operational factor, Characteristics of Users, Usefulness, Trust, Commitment) that affect virtual community success and three success factors(Sense of Virtual Community, Loyalty, Purchasing Intention) by carrying out literature review extensively and suggesting the relationship among factors. The relationship among factors were empirically validated by structural equation modeling. The data used in this study were collected from 292 users of the existing virtual communities. As the result of statistical analysis. It was found that Virtual Community Operational Factor and Characteristics of Users statistically significantly influenced Virtual Community Success. Also, it was shown that the intervening effects of Usefulness, Trust and Commitment were statistically significant, but that the relationship between commitment and Loyalty was not statistically significant. Finally, it turned out that the causality among success variables of Virtual Community was supported, but that sense of Virtual Community was required to be measured by new measurements.

• The Korean Journal of Applied Statistics
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• v.30 no.3
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• pp.391-401
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• 2017

This study develops an indicator to manage regional variations of approval rates for long-term care (LTC) service. We used LTC insurance data for grade assessment that include 433,155 applicants from 227 LTC centers across Korea in 2015. The approval rate for each center was defined as the proportion of the numbers of approved applicants out of all applicants. We assumed that the approval rates depended on the characteristics of applicants. We estimated the 'standard' approval rates from a multiple linear regression analysis using the characteristics of applicants as independent variables. The difference between the observed and the standard rates was then defined as an indicator for deviation. A center having a large difference could be considered as a center with a potential error in grade assessment. We also examined if the characteristics of investigators affected the approval rates. We found that the socio-demographic characteristics of applicants and reapplication rate for LTC grade were independent factors affecting the approval rates. Centers having the management indicator values falling outside the middle 95% of the distribution were identified as centers with an error in grading. We expect that this study will contribute to enhancing reliability and equity in LTC grading.

• Journal of The Korean Association For Science Education
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• v.37 no.2
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• pp.335-346
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• 2017

In this study, we developed and examined the validity and reliability of the Test for Indicators of Positive Experiences about Science (TIPES) that measures students' positive experiences about science. We have developed TIPES through literature reviews, development of the preliminary version of TIPES, a pilot test and revisions of the preliminary version, and the test of the final version. Through literature reviews and Delpi methods, we developed the preliminary version of TIPES, which consists of five categories such as science academic emotion, science-related self-concept, science learning motivation, science-related career aspiration, and science-related attitude. Using the preliminary version, we conducted a pilot test with 198 students consisting of 4th, 6th, 8th, and 10th graders, and modified the first version based on the results from the pilot test and expert meetings. We then conducted a main test with the revised version of TIPES with 1,841 students consisting of 4th, 6th, 8th, and 10th graders. According to a confirmatory factor analysis, a reliability test and descriptive statistics analyses, TIPES found to have a good validity as well as reliability. In addition, there are statistically significant differences in the norm distribution and scores of TIPES by student's grade, gender, school location, and level of participation in science-related activities. Discussed in the conclusion are the implications of this research for science education research and science teaching and learning practices in the school.