• Current Industrial and Technological Trends in Aerospace
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• v.6 no.2
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• pp.3-10
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• 2008

Lee, Myung-bak Administration comprises the plan to foster the Universities as a world's research and development point, and to strengthen the Institute-Academia Collaboration for the knowledge based economy in the new plan of science and technology. In addition, by participating Universities into the medium-and long-term research business of government-supported institute, it is expected to strengthen the basic initiative research, revitalize the joint study conducted by the universities and government-supported institute, and to reshuffle the statutes to promote personnel exchanges between the universities and government-supported institute. Universities role as a principle of innovation in the field of Aerospace is getting its weight so that the necessity of the institute-academia collaboration is increasing. Types of the Institute-Academia Collaboration can be categorized into the Joint-Study, internships for the students in Masters and Ph. D. programs, Professor-Researcher Exchange, Joint Research Lab, and Joint Postgraduate Course, and those are the cases from the U.S., Brazil, Germany, France, Japan, and Korea. High mutual reliance on the research subject, mutual trust on the research capability, and abundant and flexible capabilities in sources are required to make a success in Institute-Academia Collaboration.

• Investigative Magnetic Resonance Imaging
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• v.15 no.1
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• pp.57-66
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• 2011

Purpose : A new inhomogeneity correction method based on two-point Dixon sequence is proposed to obtain water and fat images at 0.35T, low field magnetic resonance imaging (MRI) system. Materials and Methods : Joint phase-magnitude density function (JPMF) is obtained from the in-phase and out-of-phase images by the two-point Dixon method. The range of the water signal is adjusted from the JPMF, and 3D inhomogeneity map is obtained from the phase of corresponding water volume. The 3D inhomogeneity map is used to correct the inhomogeneity field iteratively. Results : The proposed water-fat imaging method was successfully applied to various organs. The proposed 3D inhomogeneity correction algorithm provides good performances in overall multi-slice images. Conclusion : The proposed water-fat separation method using JPMF is robust to field inhomogeneity. Three dimensional inhomogeneity map and the iterative inhomogeneity correction algorithm improve water and fat imaging substantially.

• Journal of Oral Medicine and Pain
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• v.47 no.1
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• pp.38-51
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• 2022

Purpose: The purpose of this study was to analyze the extent of awareness and understanding of college students on temporomandibular disorder (TMD) and to search for avenues for raising public awareness and improving knowledge about TMD. Methods: One thousand and one hundred and twenty one college students in Gyeonggi-do completed a questionnaire related to awareness, experience and knowledge of TMD and collected data were analyzed by Pearson's chi-squared test. Results: Women were more significantly aware of the terms, 'TMD' (p<0.001) and 'jaw joint disease' (p<0.001) than men. Third graders were more significantly aware of the terms, 'TMD' (p<0.001) and 'jaw joint disease' (p<0.001) than any other graders. Third graders the most frequently chose to visit department of dentistry for the treatment of TMD among three graders (p<0.001). Women more frequently chose to visit department of dentistry for the treatment of TMD than men (p<0.001). Health field subjects were more significantly aware of the terms, 'TMD' (p<0.001) and 'jaw joint disease' (p<0.001) than non health field subjects. Having more frequently visited department of dentistry for the treatment of TMD than non health field subjects (p<0.001), health field subjects more frequently chose to visit department of dentistry for the treatment of TMD in the future (p<0.001). Conclusions: The level of awareness and knowledge of TMD was higher in women college students, health field subjects and third graders than men college students, non health field subjects and the rest of two graders, respectively. The higher the level of experience and education of the subject, the more aware the subject was of TMD. Therefore publicity activities and education through various routes are required to raise public awareness and knowledge of TMD. In addition, it is necessary to inform general public of the dentistry specialized for the accurate diagnosis and standardized treatment of TMD.

• Magazine of the Korea Concrete Institute
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• v.20 no.6
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• pp.75-79
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• 2008

• Proceedings of the Korea Concrete Institute Conference
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• 2000.10b
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• pp.1085-1090
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• 2000

It is socially increasing the need to maintenance of building's durability and management for building's safety. It has happened in waterproofing field, especially in case of water leakage in expansion joint and cracks, lacking basic design for waterproofing. After the completed of construction, there are many troubles something like this. Therefore it need for development to prevent from water leakage, using oakum and urethane in expansion joint and cracks as a method for waterproofing.

• Korean journal of applied entomology
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• v.32 no.2
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• pp.176-183
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• 1993

These sutdies were conducted to investigate the joint toxic action of mixtures of several acaricides including amitraz, bifenthrin, propargite, fenbutatin dxide and bxide dicofol to the field-collected strian of Tetranychus urticae. The synergistic action of acaricidal mixtures was greatly varied with the kind of acaricide combinations and their mixture ratios. The combinations of amitraz with each of the tested acaricides were synergized at the given mixture ratios. The higher synergistic action in the each combination was observed at 2 : 8 ratio of amitraz and bifenthrin, 8 : 2 ratio of amitraz and fenbutatin oxide, 4 : 6 ratio of amitraz and propargite and 6 : 4 ratio of amitraz and dicofol.

• International Journal of Highway Engineering
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• v.19 no.3
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• pp.11-18
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• 2017

PURPOSES : This study investigates the effect on concrete pavement accordance with the curing methods in cool weather and supports the best method in the field. METHODS : Two field tests evaluated the curing methods of concrete pavement in cool weather. Firstly, five curing methods were tested, including normal curing compound, black curing compound, bubble sheet, curing mat, and curing mat covered with vinyl. Concrete maturity was compared from temperature data. Secondly, normal curing compound and curing mat with vinyl, which showed the best performance, were compared in terms of maturity and join condition index. RESULTS:From the field tests, it is an evident that curing mat with vinyl accelerated the concrete strength. Therefore, it is possible to conduct saw-cut works in cool weather, which minimizes damage on concrete at joint. CONCLUSIONS : For concrete pavement in cool weather, using curing mat with vinyl as the curing method could overcome the strength delay. Therefore, strength and durability problems on concrete at joint due to cool weather would be fewer in the future.

• Geomechanics and Engineering
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• v.18 no.1
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• pp.59-69
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• 2019

Grout injection is mainly used for permeability reduction and/or improvement of the ground by injecting grout material into pores, cracks, and joints in the ground. The oscillatory grout injection method was developed to enhance the grout penetration. In order to verify the level of enhancement of the grout, field grout injection tests, both static and oscillatory tests, were performed at three job sites. The enhancement in the permeability reduction and ground improvement effect was verified by performing a core boring, borehole image processing analysis, phenolphthalein test, scanning electron microscopy analysis, variable heat test, Lugeon test, standard penetration test, and an elastic wave test. The oscillatory grout injection increased the joint filling rate by 80% more and decreased the permeability coefficient by 33-68%, more compared to the static grout injection method. The constrained modulus of the jointed rock mass was increased by 50% more with oscillatory grout injection compared to the static grout injection, indicating that the oscillatory injection was more effective in enhancing the stiffness of the rock mass.

• Computers and Concrete
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• v.32 no.4
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• pp.411-423
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• 2023

The rapid development of road transport has increased the number of bridges that require widening. A critical issue in the construction of bridge widening is the influence of vibrations of the old bridge on the casting of wet joint concrete between the old and new bridges owing to the running traffic. Typically, the bridge is closed to traffic during the pouring of wet joint concrete, which negatively affects the existing transportation network. In this study, a newly developed microscopic traffic load modeling approach and the vehicle-bridge interaction theory are incorporated to develop a refined numerical framework for the analysis of random traffic-bridge coupled dynamics. This framework was used to investigate traffic-induced vibrations at the wet joint of a widened bridge. Based on an experimental study on the vibration resistance of wet joint concrete, traffic control strategies were proposed to ensure the construction performance of cast-in-site wet joint concrete under random traffic without interruption. The results show that the vibration displacement and frequency of the old bridge, estimated by the proposed framework, were comparable with those obtained from field measurements. Based on the target peak particle velocity and vibration amplitude of the wet joint concrete, it was found that traffic control measures, such as limiting vehicle gross weight and limiting traffic volume by closing an additional traffic lane, could ensure the construction performance of the wet joint concrete.

• Journal of Welding and Joining
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• v.21 no.2
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• pp.102-110
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• 2003

A visual sensor consisted of polygonal mirror, laser, and CCD camera was proposed to measure the distance to the weld joint for recognizing the joint shape. To scan the laser beam of the sensor onto an object, 8-facet polygonal mirror was used as the rotating mirror. By locating the laser and the camera at axi-symmetrical positions around the mirror, the synchronized-scan condition could be satisfied even when the mirror was set to rotate through one direction continuously, which could remove the inertia effect of the conventional oscillating-mirror methods. The mathematical modelling of the proposed sensor with the optical triangulation method made it possible to derive the relation between the position of an image on the camera and the one of a laser light on the object. Through the geometrical simulation of the proposed sensor with the principal of reflection and virtual image, the optical path of a laser light could be predicted. The position and direction of the CCD camera were determined based on the Scheimpflug's condition to fit the focus of any image reflected from an object within the field of view. The results of modelling and simulation revealed that the proposed visual sensor could be used to recognize the weld joint and its vicinity located within the range of the field of view and the resolution. (Received February 19, 2003)