• Proceedings of the KWS Conference
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• 2002.10a
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• pp.127-132
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• 2002

Recent deepwater offshore structures in Gulf of Mexico utilize butt welded tubular joints. Application of welded tubular joint includes tendons, production risers, and steel catenary risers. Fatigue life assessment of these joints becomes more critical because the structures to which they are attached are allowed to undergo cyclic and sometimes large displacements around an anchored position. Estimating the fatigue behavior of these tubular members in the design stage is generally conducted by using S-N curves specified in the codes and standards. Applying the stress concentration factor of the welded structure to S-N approach often results in very conservative assessment because the stress field acting on the tubular has a non-uniform distribution through the thickness. Fracture mechanics and fitness for service (FFS) technology have been applied in the design of the catenary risers. This technology enables the engineer to establish proper requirements on weld quality and inspection acceptance criteria to assure satisfactory structural integrity during its design life. It also provides guidance on proper design curves to be used and a methodology for accounting for the effects of non-uniform stress distribution through the wall thickness. An attempt was made to develop set of S-N curves based on fracture mechanics approach by considering non-uniform stress distribution and a threshold stress intensity factor. Series of S-N curves generated from this approach were compared to the existing S-N curves. For flat plate butt joint, the S-N curve generated from fracture mechanics matches with the IIW class 100 curve when initial crack depth was 0.5 mm (0.02"). Similar comparison with API X′ was made for tubular joint.. These initial crack depths are larger than the limits of inspection by current Non-destructive examination (NDE) means, such as Automatic Ultrasonic Inspection (AUT). Thus a safe approach can be taken by specifying acceptance criteria that are close to limits of sizing capability of the selected NDE method. The comparison illustrates conservatism built into the S-N design curve.

• International Journal of Computer Science & Network Security
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• v.23 no.1
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• pp.153-163
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• 2023

This study is situated in the context of intelligent transport systems, where in-vehicle devices assist drivers to avoid accidents and therefore improve road safety. The vehicles present in a given area form an ad' hoc network of vehicles called vehicular ad' hoc network. In this type of network, the nodes are mobile vehicles and the messages exchanged are messages to warn about obstacles that may hinder the correct driving. Node mobilities make it impossible for inter-node communication to be end-to-end. Recognizing this characteristic has led to delay-tolerant vehicular networks. Embedded devices have small buffers (memory) to hold messages that a node needs to transmit when no other node is within its visibility range for transmission. The performance of a vehicular delay-tolerant network is closely tied to the successful management of the nodes' transit buffer. In this paper, we propose a message transit buffer management model for nodes in vehicular delay tolerant networks. This model consists in setting up, on the one hand, a policy of dropping messages from the buffer when the buffer is full and must receive a new message. This drop policy is based on the concept of intermediate node to destination, queues and priority class of service. It is also based on the properties of the message (size, weight, number of hops, number of replications, remaining time-to-live, etc.). On the other hand, the model defines the policy for selecting the message to be transmitted. The proposed model was evaluated with the ONE opportunistic network simulator based on a 4000m x 4000m area of downtown Bouaké in Côte d'Ivoire. The map data were imported using the Open Street Map tool. The results obtained show that our model improves the delivery ratio of security alert messages, reduces their delivery delay and network overload compared to the existing model. This improvement in communication within a network of vehicles can contribute to the improvement of road safety.

• International Journal of Advanced Culture Technology
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• v.11 no.1
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• pp.1-11
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• 2023

Backgrounds: As the COVID-19 pandemic continues, the university students population is one of the high risk and vulnerable groups. This study analyzed the status of student's mental health, including anxiety and depression caused by COVID-19, and its related factors among a university students in Korea. Methods : Our study subjects included university students in Korea. The survey items included general characteristics, teaching methods, physical activity, eating habits (SDBQ-L), weight-related questions, general anxiety disorder-7(GAD-7), and depression symptoms checklist. Frequency analysis, chi-square test, and logistic regression analysis were performed and data was analyzed using R version 4.1.2 program. Results : The prevalence of anxiety complaints was 5.5%, while the prevalence of depression complaints was 30.8%. In the multivariable logistic regression analysis of factors influencing anxiety, anxiety occurred 19.081 times (95% confidence interval (CI): 2.352-154.807) in the group with unhealthy diet (p<0.01). While in the multivariable analysis to identify factors affecting depression, women were 2.607 times significantly higher (95% CI: 1.255-5.415) than men, 0.407 times (95% CI:0.197-0.840) for residents of the metropolitan area, 3.418 times higher (95% CI:1.633-7.198) for unhealthy dietary people, and 2.225 times higher (95% CI: 1.080-4.582) for weight gainers (p<0.05). The type of class had no effect. Conclusions: COVID-19 and its associated interventions had negative effects on the mental health status including anxiety and depression in university students in Korea. Based on our results we recommend developing mental health interventions and prevention strategies for students in all universities in Korea.

• Korean Journal of Clinical Pharmacy
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• v.32 no.1
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• pp.13-19
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• 2022

Background: The use of combination therapy and fixed-dose combination therapy is increasing for the treatment of type 2 diabetes. Sodium glucose cotransporter-2 inhibitor (SGLT2i) is a drug class used in combination with metformin. Methods: Type 2 diabetes patients on SGLT2i/metformin combination therapy were extracted from the 2019 Health Insurance Review & Assessment Service-National Patients Sample. On July 1, 2019, SGLT2i and metformin fixed-dose combination (SGLT2i/metformin FDC) and two-pill combination (TPC) groups were identified, and a chi-square test and multiple logistic regression were performed. Results: Of total 2,992 patients, 1,077 (36%) were prescribed SGLT2i/metformin FDC and 1,915 (64%) were prescribed TPC. We found that the most common comorbidities were in the order of dyslipidemia, gastrointestinal disease, and hypertension. Multiple logistic regression analysis showed that the use of SGLT2i/metformin FDC was lower than TPC in patients with diabetic neuropathy (OR=0.76, p=0.008). Clinic (OR=2.09, p<0.001) and general hospital (OR=1.40, p=0.019) showed higher tendency to prescribe SGLT2i/metformin FDC compared to tertiary hospital. The tendency of prescribing SGLT2i/metformin FDC was lower in Kyeonggi (OR=0.79, p=0.037), Gyeongsang (OR=0.77, p=0.025) and Chungcheong (OR=0.68, p=0.007) than Seoul. Conclusion: Factors related to the use of SGLT2i/metformin FDC in patients with type 2 diabetes were complication, medical institution and region. The tendency to prescribe SGLT2i/metformin FDC was relatively higher in clinics than in tertiary general hospitals and in Seoul than in other regions.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.18 no.2
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• pp.203-228
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• 2007

This study was conducted to explore pending issues as an obstacle factor in the library growth and progress through measurement of Korean and Chinese College undergraduates' perception on the library, and suggest its countermeasure to that the study result showed that their perception to the library's social and cultural function was low, so the library's cultural events need to be consolidated to enhance perception, and the Korean student's study zeal was lower than Chinese, and amny students did not go to the library, but an incentive is needed to escalate the strength of course study or the library availability. Also a countermeasure should be established such as a class link project through continuing specialized librarians' training strengthened, users' group education for the satisfaction enhancement and validity of the information service users.

• Journal of radiological science and technology
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• v.46 no.5
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• pp.435-444
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• 2023

The purpose of this study was to analyze the factors that demographic factors, radiation knowledge level, and radiation awareness could be affecting the benefits of radiation. From July 2022 to July 2023, after receiving consent to participate by using the link of Naver through Social Network Service (SNS) for the general public, 312 people were surveyed by self-registration method without collecting personal information. The questionnaire consisted of a total of 25 questions following demographic factors (5 questions including age group by life cycle, sex, monthly household income, residence), radiation knowledge level (8 questions including basic physical, biological effects, radiation protection technology), radiation awareness (12 questions including risk, management, benefit). Independent sample T-test and ANOVA tests were performed for significant differences in the average radiation awareness between variables, and hierarchical regression was performed to identify influencing factors on radiation benefits. As a result, the benefit of radiation was significantly high among the radiation awareness, but the awareness of the danger of radiation was insufficient to the level of recognizing it as safe. Men had significantly higher awareness of radiation management and benefits than women, and the awareness of radiation management was significantly higher in the middle class with a monthly household income of 4.31 million won or more. The higher the knowledge level of radiation, the higher the awareness of the benefits of radiation. The factors that had a positive effect on radiation benefits were the high level of radiation knowledge and awareness of radiation management.

• Journal of the Korea Society of Computer and Information
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• v.28 no.11
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• pp.103-111
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• 2023

Recently, many universities have used various electronic attendance systems such as NFC, QR code, Sound-QR, Bluetooth BLE authentication, and face recognition to process attendance. However, existing methods have various problems such as attendance errors due to deformation of authentication signals, mis-recognition attendance from outside the classroom, and difficulty to process seat absence during class. Therefore, this study proposes a high-frequency signal-based electronic attendance system to solve these problems and manage more accurate electronic attendance. As the high-frequency signal replaces the BLE signal, and the transmission range of the signal is limited to the classroom, and the signal value can be immediately changed if a change of the signal is needed. To verify the performance of the proposed system, we conducted a comparative experiment with the Bluetooth based electronic attendance system, and as a result, the proposed method showed high accuracy. Thus, the proposed method will be a useful service that can be immediately used in smart device-based electronic attendance system.

• Fashion & Textile Research Journal
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• v.25 no.5
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• pp.560-567
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• 2023

This study aims to rediscover the industrial value of a borderless service in the hyper-connected era by producing fashion content at the forefront of the cultural industry as XR content and contributing to developing fashion content for edutech. The research method employed design aesthetic theory, while the empirical proposal utilized scientific knowledge information to build a framework for 3D convergence content. The characteristics of fashion content exhibitions that apply the neumorphism technique are as follows: The first is a virtual space that produces clothing culture by type. Africa, where dyeing and crafts are developed, selects a product-oriented exhibition type; Asia, where weaving and textiles are excellent, selects a random movement type; and Europe, where the evolution of clothing design over time is evident, selects a guided movement type to create a three-dimensional fashion edutech. The goal was to produce content. The second is creative reproducibility, which combines a new fashion design that embraces the aura of the original with a trendy sense. The realistic folk costume style of the original allowed for its implementation in the AR exhibition space using historical traditional style techniques such as weaving and textiles. The third is building organic, modular content. By designing and then saving/editing/arranging the basic VP zone for each style, learners and instructors can freely edit the content for each fashion class topic and create various presentations to ensure that it functions as non-face-to-face edutech content around the world.

• Journal of the Korean earth science society
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• v.22 no.5
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• pp.360-376
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• 2001

This qualitative research investigated in-service science teachers' perceptions about cooperative learning and their perceived barriers in implementing cooperative learning in their classrooms. The underlying premise for cooperative learning is founded in constructivist epistemology. Cooperative learning (CL) is presented as an alternative frame to the current educational system which emphasizes content memorization and individual student performance through competition. An in-depth interview was conducted with 18 in-service science teachers who enrolled in the first-class teacher certification program during 2001 summer vacation. These secondary school teachers's interview data were analyzed and categorized into three areas: teachers' definition of cooperative learning, issues with implementing cooperative learning in classrooms, and teachers' and students' responses towards cooperative learning. Each of these areas are further subdivided into 10 themes: teachers' perceived meaning of cooperative learning, the importance of talk in learning, when to use cooperative learning, how to end a cooperative class, how to group students for cooperative learning, obstacles to implementing cooperative learning, students' reactions to cooperative learning, teachers' reasons for choosing (not choosing) student-centered approaches to learning/teaching, characteristics of teachers who use cooperative learning methods, and teachers' reasons for resisting cooperative learning. Detailed descriptions of the teachers' responses and discussion on each category are provided. For the development and implementation of CL in more classrooms, there should be changes and supports in the following five areas: (1) teachers have to examine their pedagogical beliefs toward constructivist perspectives, (2) teacher (re)education programs have to provide teachers with cooperative learning opportunities in methods courses, (3) students' understanding of their changed roles (4) supports in light of curriculum materials and instructional resources, (5) supports in terms of facilities and administrators. It's important to remember that cooperative learning is not a panacea for all instructional problems. It's only one way of teaching and learning, useful for specific kinds of teaching goals and especially relevant for classrooms with a wide mix of student academic skills. Suggestions for further research are also provided.

• The Journal of the Korea Contents Association
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• v.18 no.5
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• pp.191-214
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• 2018

This research empirically analyzed the selection factors and the locational selection factors of the medical service facilities according to the gradual increase of the importance of the selection factors and the locational selection factors regarding the establishments of the small- and medium-sized hospitals according to the rapid changes of the socio-economic conditions. By analyzing the priority order according to the levels of the importance of each evaluation item factor through a research related to the selection factors and the locational selection factors of the small- and medium-sized hospitals and by drawing what the important factors that have the influences on the competitiveness of the pre-existent small- and medium-sized hospitals are through the classification of the real estate locational factors and the non-locational factors, the purpose lies in utilizing them as the basic data and materials for the opening strategies of the small- and medium-sized hospitals considering the special, locational characteristics according to the important factors of the selection factors of the small- and medium-sized hospitals, regarding the medical suppliers that have been preparing, for opening the new, small- and medium-sized hospitals. Based on the results of the preceding researches and the researches on the case examples, 28 evaluation factors were arrived at in terms of the level of the medical treatment, the medical services, the accessibilities of the hospitals, the conveniences of the hospitals, and the physical environment. And, regarding the 28 detailed evaluation factors that had been collected, through the interviews with the related experts, the 5 factors of the medical level, the medical service, the expertise of the hospital, the convenience of the hospital, and the physical environment were selected as the upper class evaluation factors. And, according to each upper class, a total of 28 low-part evaluation factors were selected. Regarding the optimal evaluation factors that were selected, the optimal locational factors were selected by carrying out an AHP questionnaire survey investigation with 200 medical experts as the subjects. Regarding the AHP analysis results, similarly with the case examples of the precedent researches, the levels of the importance appeared in the order of the medical level, the medical services, the accessibility of the hospital, the physical environment, and the convenience. And the factors that were related to the facilities of a hospital appeared low. The results of this research can be applied in providing the basis for the decision-makings regarding the selections of the locations of the small- and medium-sized hospitals in the future.