• Journal of the Computational Structural Engineering Institute of Korea
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• v.32 no.4
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• pp.233-240
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• 2019

Open-hole tensile tests are usually performed to measure the tensile strengths of composites as they are an essential parameter for designing composite structures. However, correctly modeling the tensile test is extremely challenging as it involves various damages such as fiber and matrix damage, delamination, and debonding damage between the fiber and matrix. Therefore, a progressive damage model was developed in this study to estimate the in-plane failure and delamination between the fiber and matrix. The Hashin damage model and cohesive zone approach were used to model ply and delamination failures. The results of the present model were compared with previously published experimental and numerical findings. It was observed that neglecting delamination during finite element analysis led to overestimation of tensile strength.

• Journal of The Korean Astronomical Society
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• v.50 no.3
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• pp.51-59
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• 2017

The presence of blue stragglers pose challenges to standard stellar evolution theory, in the sense that explaining their presence demands a complex interplay between stellar evolution and cluster dynamics. In the meantime, mass transfer in binary systems and stellar collisions are widely studied as a blue straggler formation channel. We explore properties of the Galactic open clusters where blue stragglers are found, in attempting to estimate the relative importance of these two favored processes, by comparing them with those resulting from open clusters in which blue stragglers are absent as of now. Unlike previous studies which require a sophisticated process in understanding the implication of the results, this approach is straightforward and has resulted in a supplementary supporting evidence for the current view on the blue straggler formation mechanism. Our main findings are as follows: (1) Open clusters in which blue stragglers are present have a broader distribution with respect to the Z-axis pointing towards the North Galactic Pole than those in which blue stragglers are absent. The probability that two distributions with respect to the Z-axis are drawn from the same distribution is 0.2%. (2) Average values of $log_10(t)$ of the clusters with blue stragglers and those without blue stragglers are $8.58{\pm}0.232$ and $7.52{\pm}0.285$, respectively. (3) The clusters with blue stragglers tend to be relatively redder than the others, and are distributed broader in colors. (4) The clusters with blue stragglers are likely brighter than those without blue stragglers. (5) Finally, blue stragglers seem to form in condensed clusters rather than simply dense clusters. Hence, we conclude that mass transfer in binaries seems to be a relatively important physical mechanism of the generation of blue stragglers in open clusters, provided they are sufficiently old.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.10 no.1
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• pp.69-82
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• 2002

Recently, it appears that the major change in open skies agreement established the bilateral agreement and sub-regional multi-lateral agreement system with U.S.A. as the central figure. Specifically sub-regional multi-lateral air transportation cooperation is based on the bilateral agreement systems among the like minded countries. To develop the air transportation industry, Each country tries to come true free air transportation in bloc and deregulation in terms of market approach and traffic right. The purpose of this study is to look into the background of sub-regional air transportation cooperation and to expect the economic impact of the open skies agreement. We selected the Singapore in Asia-Pacific region as the subject of investigation. Even though Singapore is a small country in Asia-Pacific region. They have global competition power which is airport field as well as to airlines and tourism industry. Under this condition, we analyzed the economic impact of the open skies policy through the Input/Output analysis.

• The Mathematical Education
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• v.44 no.2 s.109
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• pp.307-323
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• 2005

The purpose of this study was to develop a program to cultivate mathematical creativity based on open-ended problem and to investigate its effect. The major features of this innovative program are (a) breaking up fixations, (b) multiple answers, (c) various strategies, (d) problem posing, (e) exploring strategies, (f) selecting and estimating, (g) active exploration through open-ended problems. 20 units for 7th grade mathematics were developed. This study hypothesizes that experimental students may develop more divergent thinking abilities than their traditional counterparts. The participants were 7th grade students attending middle schools in Seoul. Instruments were pre and post tests to measure mainly divergent thinking skills through open-ended problems. The results indicated that the experimental students achieved better than the comparison students on overall and each component of fluency, flexibility, and originality of divergent thinking skills, when deleting the effect of covariance of the pretest. The developed program can be a useful resource for teachers to use in enhancing their students' creative thinking skills. Further this open-ended approach can be served as a model to implement in classes. This study suggests that further investigations are needed in order to examine effects on affective domains such as motivation and task perseverance which are also considered as important factors of creativity.

• Journal of Trauma and Injury
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• v.23 no.2
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• pp.175-179
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• 2010

Purpose: Sternal fractures after blunt thoracic trauma can cause significant pain and disability. They are relatively uncommon as a result of direct trauma to the sternum and open reduction is reserved for those with debilitating pain and fracture displacement. We reviewed consecutive 11 cases of open reduction and fixation of sternum and tried to find standard approach to the traumatic sternal fractures with severe displacement. Methods: From December 2008 to August 2010, the medical records of 11 patients who underwent surgical reduction and fixation of sternum for sternal fractures with severe displacement were reviewed. We investigated patients' characteristics, chest trauma, associated other injuries, type of open reduction and fixation, combined operations, preoerative ventilator support and postoperative complications. Results: The mean patient age was 59.3years (range, 41~79). The group comprised 6 male and 5 female subjects. Among 11 patients who underwent open reduction and fixation for sternal fracture with severe displacement, 6 cases had isolated sternal fractures and the other 5 patients had associated other injuries. Sternal fractures were caused by car accidents (9/11, 81.8%), falling down (1/11, 9.1%) and direct blunt trauma to the sternum (1/11, 9.1%), respectively. 3 of the 7 patients (42.9%) who underwent sternal plating with longitudinal plates showed loosening of fixation. Otherwise, none of the 4 patients who underwent surgical fixation using T-shaped plate had stable alignment of the fracture. Conclusion: Sternal fractures with severe displacement need to be repaired to prevent chronic pain, instability of the anterior chest wall, deformity of the sternum, and even kyphosis. In the present study, a T-shaped plate with a compression-tension mechanism constitutes the treatment of choice for displaced sternal fractures.

• Journal of Information Management
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• v.39 no.4
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• pp.1-20
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• 2008

The purpose of this study is to scrutinize the copyright issue under Open Access environment. A survey has been carried out to investigate researchers' awareness and recognitions about such issues. For this, bioinformatics researchers were selected and surveyed. Descriptive statistics method is employed for analysis of collected data. The findings of this study summarized as follow. (1) Although the researchers regarded the Open Access a positive initiative, the perceptions about open access were very low. (2) The researchers demanded possession of copyright depending on type of research information. (3) Many agencies did not required the transfer of copyright to the researcher. Thus, there is a possibility of dispute regarding copyright issues between researchers and agencies. (4) The researchers are willing to participate in open access activity on the assumption that their study is used in legitimate objective. On the basis of these findings, suggestions are added in as an impetus to lower the barrier against a copyright and higher the approach to information seekers and information providers.

• The korean journal of orthodontics
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• v.44 no.4
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• pp.203-216
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• 2014

The purpose of the current report is to present 6-year long-term stability and 10-year follow-up data for an adult patient who was treated with a tongue elevator for relapsed anterior open-bite. The 19-year-old male patient presented with the chief complaint of difficulty in chewing his food. Collectively, clinical and radiographic examinations revealed an anterior open-bite, low tongue posture, and tongue-tie. The patient opted for orthodontic treatment alone, without any surgical procedure. A lingual frenectomy was recommended to avoid the risk of relapse, but the patient declined because he was not experiencing tongue discomfort. Initial treatment of the anterior open-bite with molar intrusion and tongue exercises was successful, but relapse occurred during the retention period. A tongue elevator was used for retreatment, because the approach was minimally invasive and suited the patient's requirements regarding discomfort, cost, and time. The appliance changed the tongue posture and generated an altered tongue force, which ultimately resulted in intrusive dentoalveolar effects, and a subsequent counterclockwise rotation of the mandible. The results showed long-term stability and were maintained for six years through continual use of the tongue elevator. The results of this case indicated that a tongue elevator could be used not only as an alternative treatment for open-bite, but also as an active retainer.

• Journal of The Korean Association For Science Education
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• v.21 no.2
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• pp.255-263
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• 2001

The purpose of this study is to analyse the eighth grade students' performance of open investigations for two kinds of tasks: the qualitative one which involves the descriptive approach through observation, and the quantitative one which involves the quantitative data processing through control of variables. Researcher's observation, interview data as well as students' investigation reports, self-evaluations were analysed. The difficulties of qualitative open investigation lie in detecting and dealing with unexpected observations, of which the acceptance and interpretation were influenced by preconceptions. On the other hand, managing several variables, making reliable and valid measures, and quantitative data processing constituted main difficulties of quantitative open investigation. Some students could recognize the deficiencies of their methods and findings in qualitative one, but few in quantitative one. These results suggest the teaching point for each task of open investigations.

• The Journal of the Convergence on Culture Technology
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• v.4 no.4
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• pp.373-377
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• 2018

In this paper, we propose an implementation of a neural network accelerator for reducing the rendering noise using OpenCL. Among the rendering algorithms, we selects a ray tracing to assure a high quality graphics. Ray tracing rendering uses ray to render, less use of the ray will result in noise. Ray used more will produce a higher quality image but will take operation time longer. To reduce operation time whiles using fewer rays, Learning Base Filtering algorithm using neural network was applied. it's not always produce optimize result. In this paper, a new approach to Matrix Multiplication that is based on General Matrix Multiplication for improved performance. The development environment, we used specialized in high speed parallel processing of OpenCL. The proposed architecture was verified using Kintex UltraScale XKU6909T-2FDFG1157C FPGA board. The time it takes to calculate the parameters is about 1.12 times fast than that of Verilog-HDL structure.

• Journal of Korean Foot and Ankle Society
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• v.28 no.1
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• pp.8-14
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• 2024

Purpose: Ankle fracture fixation is the gold standard of treatment but it does have its own complications. There is inadequate data regarding the comparative effectiveness of early vs. delayed fixation for open ankle fracture outcomes. This study compares the clinical and functional outcomes of open ankle fractures treated by early or delayed definitive fixation and identifies the limitations of both methods. Materials and Methods: All 73 patients enrolled in the study underwent surgical intervention within 24 hours of injury. The early fixation group (group A) consisting of 39 patients underwent definitive fixation as an index procedure, while the delayed fixation group (group B) consisted of 34 patients who underwent debridement and external fixator application as an index procedure and definitive fixation when soft tissue condition was conducive. All patients were evaluated at 2, 6, and 12 weeks postoperatively and then three monthly for a year. Results: Enneking and American Orthopaedic Foot and Ankle Society scores were markedly higher in the early fixation group at 6 months postoperatively (p-values <0.001 and 0.011, respectively). However, no discernible intergroup difference was evident at 12 months postoperatively. Between 6 and 12 months, group functional outcome scores were significantly different. At 6 months, there was a substantial difference in dorsiflexion between the two groups (p-values 0.001 and <0.001, respectively), but no difference was observed at 12 months postoperatively. At 6 and 12 months, group average plantar flexions were non-significantly different. Conclusion: Early definitive fixation of complex ankle fractures using a targeted approach produced promising results for lower grade open fractures (grades 1 and 2), and delayed definitive fixation, after initial external fixation to allow for soft tissue stabilization, produced promising results for higher grade open fractures (grades 3A and 3B). At 12-month follow-ups, clinical and functional outcomes achieved using these strategies were equivalent.