• Journal of the Korean Geotechnical Society
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• v.25 no.12
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• pp.5-12
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• 2009

As rock bolts become one of the main support systems in tunnels and underground structures, the integrity of the rock bolts affects the safety of these structures. The purpose of this study is the evaluation of rock bolt integrity using wavelet transforms of the guided ultrasonic waves by using transmission test in the field. After several rock bolts with various defect ratios are embedded into a large scale concrete block and rock mass, guided waves are generated by a piezo disk element and measured by an acoustic emission (AE) sensor. The captured signals are analyzed in the time-frequency domain using the wavelet transform based on a Gabor wavelet. Peak values in the time-frequency domain represent the interval of travel time of each echo. The energy velocities of the guided waves increase with an increase in the defect ratio. The suitable curing time for the evergy velocity analysis is proposed by the laboratory test, and in-situ tests are performed in two tunnelling sites to verify the applicability of rock bolt integrity tests performed after proposed curing time. This study proves that time-frequency domain analysis is an effective tool for the evaluation of the rock bolt integrity.

• Journal of the Korean Geotechnical Society
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• v.26 no.7
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• pp.17-24
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• 2010

Load Resistance Factor Design method is used increasingly in geotechnical design world widely and resistance factors for drilled shafts are suggested by AASHTO. However, these resistance factors are determined for intact rock conditions; by comparison, most of bedrocks in Korea have weathered condition, so that applying the AASHTO resistance factors is not reasonable. Thus, this study suggests the proper resistance factors for design of drilled shaft in Korea. The 22 cases of pile load test data from 8 sites were chosen and reliability-based approach is used to analyze the data. Reliability analysis was performed by First Order Second Moment Method (FOSM) applying 4 bearing capacity equations. As a result, when the Factor of Safety (FOS) was selected as 3.0, the target reliability indexes (${\beta}_c$) were evaluated as 2.01~2.30. Resistance factors and load factors are determined from optimization based on above results. The resistance factors ranged between 0.48 and 0.56 and load factors for dead load and live load are evaluated as approximately 1.25 and 1.75 respectively. However, when the target reliabilities are considered as 3.0, the resistance factors are evaluated as approximately 50% of the results when the target reliability index was 2.0.

• Journal of the Korean Geotechnical Society
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• v.23 no.12
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• pp.83-94
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• 2007

Piled raft foundations have been highlighted as an economical design concept of pile foundations in recent years. However, piled raft foundations have not been widely used in Korea due to the difficulty in estimating the complex interaction effects among rafts, piles and soils. The authors developed an effective numerical program to analyze the behavior of piled raft foundations for practical design purposes and presented it briefly in this paper. The developed numerical program simulates the raft as a flexible plate consisting of finite elements with eight nodes and the raft is supported by a series of elastic springs representing subsoils and piles. This study imported another model to simulate pile groups considering non-linear behavior and interaction effects. The apparent stiffnesses of the soils and piles were estimated by iterative calculations to satisfy the compatibility between those two components and the behavior of piled raft foundations can be predicted using these stiffnesses. For the verification of the program, the analysis results about some example problems were compared with those of rigorous three dimensional finite element analysis and other approximate analysis methods. It was found that the program can analyze non-linear behaviors and interaction effects efficiently in multi-layered soils and has sufficient capabilities for application to practical analysis and design of piled raft foundations.

• Knowledge Management Research
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• v.24 no.1
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• pp.99-126
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• 2023

As cultural background contributes members of society to recognize and behave in a specific direction, customers with different cultural backgrounds show various reactions even when they are provided with the same service. Previous studies have used the Hofstede cultural dimension to understand how hotel visitors' satisfaction varies with the provided service as per their cultural background. However existing research only considered the cultural background of the guests, and there are not many studies focused on the types of travel. Therefore, in this study, the travel types of hotel visitors are classified into business travel visitors and leisure tourism visitors, and analyzed the effect of Hofstede's cultural dimension on hotel selection attributes according to the styles of travel. In this study, we collected information on six cultural dimensions of Hofstede, and from TripAdvisor, a representative tourism platform, 204,261 optional attribute ratings for hotels in New York to investigate the satisfaction of hotel selection attributes. In conclusion, it is expected that this study will be able to identify which service attributes the customers of various cultures who visit hotels put emphasis in advance, and therefore provide suitable service accordingly.

• Journal of the Korea Society of Computer and Information
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• v.14 no.10
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• pp.43-53
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• 2009

Knowledge retrieval service that uses collective intelligence which has special quality of open structure and can share the accumulative data is gaining popularity. However, acquiring the right needs for users from massive public knowledge is getting harder. Recently, search results from Google which is known for it's exquisite algorism, shows results for collective intelligence such as Wikipedia, Yahoo Q/A at the highest rank. Objective of this paper is to show that most answers come from human and to find the most influential people in on-line knowledge retrieval service. Hereupon, this paper suggest the influence value calculation algorism by analyzing user relation as centrality which social network is based on user activeness and reliance in Naver 지식iN. The influence value calculated by the suggested algorism will be an important index in distinguishing reliable and the right user for the question by ranking users with troubleshooting solutions in the knowledge retrieval service. This will contribute in search satisfaction by acquiring the right information and knowledge for the users which is the most important objective for knowledge retrieval service.

• Journal of Digital Convergence
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• v.20 no.3
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• pp.407-413
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• 2022

Existing clothing recommendation systems remain at the level of showing appropriate photos when a user selects a type of clothing he or she likes after entering his or her own body size or body size. When a user purchases clothing using such recommendation systems, there are many cases in which it does not fit or does not fit the user's body size. In this study, to solve these problems of existing clothing recommendation systems, a system was implemented in which the user receives not only size but also skin tone and recommends clothing suitable for the user's body size as well as skin tone. In this system, clothing size information obtained through web crawling was periodically stored in a database for eight male tops to recommend clothing, and the entire pixel of the clothing image was analyzed to extract color text values. In order to confirm the performance of this system, a survey was conducted on 100 male college students, and the satisfaction level was 70%. Most of the reasons for not being satisfied are that the recommended clothing is limited, so it is judged that it is necessary to expand the target clothing in the future.

• Journal of the Korean Society for information Management
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• v.39 no.1
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• pp.171-193
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• 2022

In contemporary society, the importance of 'Citizen Participation' has been recognized and actively used in various fields. Archives are also planning citizen participation activities according to the trend, but there is a limit to taking the form of passive participation activities such as participation in contests and donation of records. The ultimate purpose of this study is to prepare issues and specific action plans to induce more active citizen participation in domestic archives. To this end, first, previous studies related to citizen participation in the field of records management were reviewed, and terms and concepts were established. Next, advanced cases that are stably operating overseas were selected and analyzed from various aspects, and through this, specific program operation elements and pros and cons were identified. After that, the current status of domestic archives that have or are planning to engage in citizen participation activities was investigated to derive factors to be considered from a practical point of view when introducing the actual program. Based on this study, it is hoped that it will contribute to the establishment of a participating recording culture by designing and operating Citizen-Participating Programs suitable for individual archives.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.1
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• pp.24-35
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• 2023

Rapid industrialization and urbanization have led to severe marine pollution. A Water Quality Index (WQI) has been developed to allow the effective management of marine pollution. However, the WQI suffers from problems with loss of information due to the complex calculations involved, changes in standards, calculation errors by practitioners, and statistical errors. Consequently, research on the use of artificial intelligence techniques to predict the marine and coastal WQI is being conducted both locally and internationally. In this study, six techniques (RF, XGBoost, KNN, Ext, SVM, and LR) were studied using marine environmental measurement data (2000-2020) to determine the most appropriate artificial intelligence technique to estimate the WOI of five ecoregions in the Korean seas. Our results show that the random forest method offers the best performance as compared to the other methods studied. The residual analysis of the WQI predicted score and actual score using the random forest method shows that the temporal and spatial prediction performance was exceptional for all ecoregions. In conclusion, the RF model of WQI prediction developed in this study is considered to be applicable to Korean seas with high accuracy.

• Journal of Convergence for Information Technology
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• v.12 no.3
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• pp.186-192
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• 2022

This study investigated 110 contractual industries to identify the effects of curriculum development and educational environment improvement through Ulsan College LINC+ Program on job education and training. As a result of the study, core competency and job competency were 5.73 points each in field practice and educational environment, and job performance was significant with OJT 5.58 points and 5.74 points for educational environment(p<0.05). The relationship between suitability of the curriculum, educational environment, and recruitment performance was significant with 5.73 points for OJT, 5.74 points for field training during the education and training period, and 5.79 points for educational environment, and job reeducation/training expense was significant with 5.73 points for OJT and 5.79 points for educational environment(p<0.05). Also, students who completed the LINC+business curriculum shortened their job period by 1 to 6 months in 86.3% of the respondents, and responded that the education expense for new employees was reduced. Therefore, it was identified that the LINC+ Program of Ulsan College has the effect of shortening the job adaptation period and reducing education expenses for new employees by operating the curriculum reflecting the needs of the industry and improving the same educational environment as the industrial field.

• Korea Science and Art Forum
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• v.19
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• pp.735-745
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• 2015

This study is about the marketing mix of convention destination, aims to examine convention destination image and loyalty. In order to study the marketing mix more scientifically, this paper select those indexes which can promote the destination image but also can guide the access loyalty of exhibition participants. In addition, in order to understand the influence of marketing mix of convention destination which includes products, place, price, promotion, people, on destination image and loyalty, this research analyses the beneficial effect among variables. Based on previous research, the marketing mix of convention destination export products, place, price, promotion, people, convention image exports Cognitive images and Emotional images. The results show that, assuming that the beneficial effect of convention marketing mix on cognitive images was established partly, the beneficial effect of convention marketing mix on emotional images was established partly, the beneficial effect of marketing mix of convention destination on loyalty was established partly, the beneficial effect of cognitive images of convention destination on loyalty was established, he beneficial effect of emotional images of convention destination on loyalty was established. Based on the results of the study, a comprehensive strategic management on arketing mix of convention destination, played a profound impact on forming the image of the participants and enlivening the convention destination.