• Journal of Welding and Joining
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• v.12 no.1
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• pp.102-115
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• 1994

This paper is to evaluate the fatigue strength of lap joints of materials applied to LNG carrier cargo containment of GAZ-TRANSPORT(GT) type, which was welded by manual and automatic TIG welding process. The thicknesses of lapped members were 1.5mm/1.5mm or 1.5mm/0.7mm in Invar to Invar joint, and 1.5mm/8.0mm in Invar to stainless steel joint, respectively. These lap joints were mainly applied to the membrance fabrication of GT-LNG carrier. Fatigue tests of Invar/Inar lap joints were conducted under the stress ratio R=0 at room temperature. The effect of mean stress and cumulative fatigue damage on the allowable stress of Invar lap joint was evaluated on the basis of test results. Fatigue test was also conducted on Inver/Stainless steel lap joints welded by automatic TIG process without filler metals. The fatigue test of the joint was carried out under the same conditions as those of Invar/invar lap joints. The fatigue strength of the joint welded without filler metal was comparable to those welded with filler metal quoted from reference. The fatigue strength of Invar/stainless steel lap joint was only dependent on the lap throat thickness, and not on the welding process. Based on test results, the applicability of TIG welding process without filler metal in Invar/stainless steel lap joint was reviewed by controlling welding variables to assure the valid throat thickness of lap joints.

• Fire Science and Engineering
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• v.33 no.5
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• pp.86-93
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• 2019

Previous studies related to evacuation guidance systems are focused on the system construction, and research on manual of the standard evacuation map is insufficient. Therefore, this research is a basic study to establish the standard evacuation map, and analyzed the decision-making time according to the type and size for each component of the evacuation map. Experimental elements were derived through the review of previous studies and legal regulations. After that, decision-making time was analyzed according to the type and size of the component display method. An experiment was conducted to analyze the decision-making time according to the type and size of the component display method. Afterwards, through the statistical test, the evacuation map guidelines for smartphones were proposed.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.7 no.1
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• pp.115-126
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• 2008

Since the ITS project of Gwacheon city has been implemented in 1998, feasibility analysis for various ITS projects has been conducted in quantitative and qualitative aspects. However, ITS operation manual that describes the universal standards comprehensive methodology for survey and analysis for the qualitative effects of the ITS. Although it its difficult to measure the qualitative elements, the effectiveness and achievement of ITS project can be directly evaluated from the user survey. A comprehensive methodology proposed in this paper includes the design and implementation of the qualitative survey, the procedure of data analysis, the evaluation, and proposing the enhancements. The proposed methodology that take both quantitative and qualitative aspects into account, therefore, can lead the accurate and effective assessment of ITS projects.

• Journal of the Earthquake Engineering Society of Korea
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• v.20 no.7_spc
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• pp.443-451
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• 2016

A Gyeongju earthquake in the magnitude of 5.8 on the Richter scale (the moment magnitude of 5.4), which was recorded as the strongest earthquake in Korea, occurred in September 12, 2016. Compared with the 2011 Virginia earthquake, the moment magnitude was slightly smaller and its duration was 3 seconds, much shorter than 10 seconds of the Virginia earthquake, resulting in relatively minor damage. But the two earthquakes are quite similar in terms of the overall scale, unexpectedness, and social situation. The North Anna Nuclear Power Plant, which is a nuclear power plant located at 18 km away from the epicenter of the Virginia earthquake, had no damage to nuclear reactors because the reactors were automatically shut down as the design basis earthquake value was exceeded. Ground accelerations of the 2016 Gyeongju earthquake did not exceed the threshold value but the manual shutdown was carried out so that Wolsong Nuclear Power Site was not damaged. Damaged historic homestead house and masonry structures due to the Virginia earthquake have been repaired, reinforced, and rebuilt based on a long-term earthquake recovery project. Likewise, it will be necessary to carefully carry out an earthquake recovery planning program to improve overall seismic performance and to reconstruct the historic buildings and structures damaged as a result of the Gyeongju earthquake.

• Journal of the Korean Recycled Construction Resources Institute
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• v.4 no.4
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• pp.496-503
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• 2016

This paper studies the leakage situation of domestic residential building underground parking lots and main leakage areas. 18 complexes were studied and the results showed that 80% of buildings with exterior waterproofing had no leakage, but all buildings with interior waterproofing had leakage. According to a survey among professionals, water leakage problems are considered to be severe in underground parking lots and a preventative measure is required by the government. By comparing the survey and the actual situation at hand, the results showed that the lowest floor slab, wall construction joints, and floor expansion joints were the most prone to leakage. Based on the results, further study to develop a design manual for the appropriate prevention of leakage is deemed necessary.

• Journal of Periodontal and Implant Science
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• v.50 no.4
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• pp.209-225
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• 2020

Purpose: Marginal bone loss (MBL) is an important clinical issue in implant therapy. One feature that has been cited as a contributing factor to this bone loss is peri-implant mucosal thickness. Therefore, in this report, we conducted a systematic review of the literature comparing bone remodeling around implants placed in areas with thick (≥2-mm) vs. thin (<2-mm) mucosa. Methods: A PICO question was defined. Manual and electronic searches were performed of the MEDLINE/PubMed and Cochrane Oral Health Group databases. The inclusion criteria were prospective studies that documented soft tissue thickness with direct intraoperative measurements and that included at least 1 year of follow-up. When possible, a meta-analysis was performed for both the overall and subgroup analyses. Results: Thirteen papers fulfilled the inclusion criteria. A meta-analysis of 7 randomized clinical trials was conducted. Significantly less bone loss was found around implants with thick mucosa than around those with thin mucosa (difference, -0.53 mm; P<0.0001). Subgroups were analyzed regarding the apico-coronal positioning, the use of platform-matched vs. platform-switched (PS) connections, and the use of cement-retained vs. screw-retained prostheses. In these analyses, thick mucosa was found to be associated with significantly less MBL than thin mucosa (P<0.0001). Among non-matching (PS) connections and screw-retained prostheses, bone levels were not affected by mucosal thickness. Conclusions: Soft tissue thickness was found to be correlated with MBL except in cases of PS connections used on implants with thin tissues and screw-retained prostheses. Mucosal thickness did not affect implant survival or the occurrence of biological or aesthetic complications.

• Journal of the HCI Society of Korea
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• v.7 no.2
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• pp.11-16
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• 2012

R&D Strategic Planning plays a crucial role in determining success or failure of R&D. However, current automatic services for supporting the purpose merely provide fragmentary quantitative/qualitative analytics, and force domain experts to carry out further manual analysis by themselves. Thus, this study aims at automatically supporting R&D strategic planning with efficiency and effectiveness. To achieve the goal, we design major services in the viewpoint of the relationship between technology and R&D actor, which are essential elements in R&D. 'Trends and Predictions', 'Technology Levels', 'Relationship Paths', 'Roadmaps', and 'Competitors and Collaborators' services were designed and implemented on about 15 millions papers and patents. Future works will include the support of higher level in the hierarchy of strategic intelligence.

• Journal of Digital Contents Society
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• v.13 no.2
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• pp.159-167
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• 2012

Eye tracking technology tracks human eyes movements to understand user's intention. This technology has been improving slowly and should be used for a variety of occasions now. For example, it enables persons with disabilities to operate a computer with their eyes. This article will show a typical implementation of an eye tracking system for persons with disabilities, after introducing the design principles and specific implementation details of an eye tracking system. The article discussed the realization of self-adapting regulation algorithm in detail. The self-adapting algorithm is based on feedback signal controlling the lens movements to realize automatic focus, and to get a clear eyes image. This CCD camera automatic focusing method has self-adapting capacity for changes of light intensity on the external environment. It also avoids the trouble of manual adjustment and improves the accuracy of the adjustment.

• Journal of the Ergonomics Society of Korea
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• v.34 no.1
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• pp.1-10
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• 2015

Objective: The purpose of this paper is to evaluate old and newly designed ammunition boxes from an ergonomic point of view. Background: The ammunition boxes made of wood, which are currently used by the military, have some difficulties such as corrosion and damage of ammunition, environmental pollution, and stock management. Also, damages to the wooden ammunition boxes take place frequently, because soldiers carry them manually. Method: Sixteen participants volunteered to randomly perform lifting, carrying, and side-by-side moving tasks with 4 different old and new boxes, respectively for the ammunitions of 5.56mm, 60mm, 81mm, and 105mm in diameter. The old boxes are made of wood and are currently used in the military, while the new boxes are made of plastics. The joint moments of the elbow, shoulder, back, and knee were measured by using a motion analysis system and force platforms. In addition, an electromyographic system was used to measure the forces of hand and wrist muscles. Results: In most tasks, new boxes caused less joint moments at the elbow and shoulder than old boxes, because the new boxes were lighter and smaller than the old boxes. New boxes also derived less hand and wrist muscle forces due to the provision of fixed hard handles rather than string handles. Conclusion: The ergonomically designed new boxes could reduce the physical stresses of soldiers manually handling ammunitions and be helpful for storage and reuse. Application: This study shows an ergonomic application example for product development and evaluation.

• Journal of Digital Convergence
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• v.13 no.5
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• pp.309-316
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• 2015

The styles by character type in customizing systems were analyzed, being classified into creative style, attractive style, grotesque style, usual style, and suit style on the basis of the 'fashion style types of game characters' proposed in the previous research. The creative and convergent designs that couldn't be implemented in reality were expressed in various forms because those designs were created in virtual space, one feature of games. The analysis of the fashion styles of characters was focused on the RPG using the characters with exaggerated body proportions beyond the general body proportions in reality and the features on game characters that were identified by gamers. Thus, the creative style and attractive style showed a high frequency. The common features were identified because the costume designs and colors for characters are generally selected in accordance with the gamers' requests or by reflecting the view on the world. However, it was difficult to find out the representative cases for hair designs and colors because of excessively diverse expressions. The results of this paper will be a valuable reference for the research on the fashion item development manual satisfying the gamers' personalities and requests and relevant research.