• Computers and Concrete
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• v.31 no.2
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• pp.163-171
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• 2023

Face gear transmission is widely used in aerospace shunt-confluence transmission system. Tooth wear is one of the main factors affecting its bearing transmission performance. Furthermore, the installation errors of face gear are inevitable. In order to study the wear mechanism of face gear tooth surface with installation errors, based on tooth contact analysis numerical method and Archard wear theory, the UMESHMOTION subroutine in ABAQUS is developed.Combining with Arbitrary Lagrangian-Eulerian adaptive mesh technology, the finite element mesh wear model of abraded face gear pair is established.The preprocessing conditions are set to generate the inp files.Then,the inp files for each corner are imported and batch processed in ABAQUS.The loading tooth contact problem at each rotation angle is solved and the load distribution coefficient among gear tooth, tooth root bending stress, tooth surface contact stress and loaded transmission error are obtained. Results show that the tooth root wear is the most serious and the wear at the pitch cone is close to 0.The wear law of tooth surface along tooth width direction is convex parabola and the wear law along tooth height direction is concave parabola.

• Journal of the Society of Naval Architects of Korea
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• v.61 no.3
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• pp.185-199
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• 2024

Global warming impacts every corner of human life. Maritime transportation and shipbuilding industries are no exception. Recent counteraction in maritime industries is accelerating to meet the zero emission by 2050. Various alternative energy sources have been studied, and recent developments in Europe show that the windship, as a proven technology, can be an attractive candidate to solve the problem. In this paper, as the alternative transportation option, to infer the performances of modern windships, the non-dimensional ratios of past tall ships and windships are studied and reviewed. In addition, the ratios are compared to estimate the position of current and future windships under consideration. It is found that regarding the ratio distributions, the current windships being planned can be either wind-assisted propulsion ships or less fully functional windships than the past tall ships.

• Journal of the Korean housing association
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• v.26 no.2
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• pp.13-20
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• 2015

Single household is expected to be the typical form of future Korean elderly household from reduction of household size and rapid growth of the elderly. As Japanese solve the same problem with Senior Sharehouse, a case study on Senior Sharehouse in japan focused on the Spatial Arrangement and Spatial Composition could suggest an potential applications in Korea. In conclusion, compare to Korea, the Senior Sharehouse in Japan supplies additional $7.5{\sim}9.3m^2$ more space to support the physical movement of the elderly and to help the elderly to solve various functions at one space. The independence and privacy of residents are also assured by supplying single occupancy. Space analysis shows that public space is as spacious (47.3~55%) as personal space. The result of the Space analysis suggests that the sharehouse provides rational ratio of space to assure residents' independence. It was supposed that the center type would be the main stream of the Spatial Arrangement for sharehouse considering its characteristic of sharing space. But, the Senior Sharehouse in Japan prefers corner type. The guarantee of personal space is being considered as a important characteristic. As a result of case analysis, Senior Sharehouse can be a proper type of house for single elderly household and present study can be used for the baseline data to solve the residence problem for single elderly household in Korea.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.10
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• pp.2489-2496
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• 2014

The existing ship repair tool management system based on hand writing has many problems such as frequent loss of tool and overdue. To solve this problem, same systems have adopted the bar-code system. However, the systems can't cope with a problem to substitute spurious tool for genuine one on bar-code damage. Therefore, additional validation steps are necessary in order to manage expensive ship repair tool. In this paper, we propose an image comparison method for ship repair tool management. To be more concrete, we propose a normalization method and determination conditions for image comparison to use characteristics of mobile device. The normalization method makes use of the characteristics of mobile device that provides functions of real time recording, overlapping and cropping images. The proposed method applies three conditions(sum of inner angles, size of angle, position of corner coordinates) into the comparison module. The implemented system shows good performance on change direction, lighting, size and etc. The accuracy is more than 95%.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.9 no.5
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• pp.678-686
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• 1998

This paper describes an anisotropic perfectly matched layer (APML) for mesh truncation of the Finite Difference Time Domain(FDTD) method. The APML method can classified by a split type and an unsplit type, in case of the split type be made up 12 equations or 8 equations largely, and in case of the unsplit type be made of 6 equations. Therefore the latter is more simple as compare with the former. For the APML method presented in this paper is the latter, is directly derived from the time domain equations of Maxwell and extend to the three dimensional problem for the method suggested by Chen. Especially, in the edge and corner parts except the planes, the APML method effectively treated as compound with the Chen's method and Gedney's method newly. The results of the numerical method in this paper show the radiation patterns and the time responses of electromagnetic fields of the wire antennas according to wavelengths and the APML results are compared with Mur's first order absorbing boundary condition and Kraus's analytical results. Eventually, Mur's first order condition have many errors at the edge and corner. On the other hand, in comparison with Kraus's analytical results, it is quite good agreement, and the validity of present method is confirmed.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.36 no.4
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• pp.156-163
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• 2023

Objectives : The purpose of this study is to report the effect of Korean medical treatments on idiopathic bilateral strabismus. Methods : We treated a 43-year-old male idiopathic bilateral strabismus patient who was told to wait without a prescription as there was no problem in intraocular pressure test, fundus test, brain computed tomography, brain magnetic resonance imaging and angiography test, and cerebrospinal fluid test. The patient was admitted to Cheonan Korean medical hospital for 3 months to get Korean medical treatments including acupuncture, electroacupuncture, vapor treatment, pharmacopuncture therapy. The degree of improvement in idiopathic bilateral strabismus was determined by the objective measures of internal and external rotation disorders, and the patient's subjective opinions on eye pain and double vision discomfort. Results : The results of this patient showed distinct improvements on objective measures of internal and external rotation disorders in both eyes. Distance from the outer corner of the right eye when abducted decreased from 7mm to 0mm, and left eye decreased from 7mm to 0mm. Distance from the inner corner of the right eye when adducted decreased from 5mm to 0mm, and left eye decreased from 4mm to 0mm. In addition, eye pain decreased from 10 to 0 and diplopia decreased from 10 to 2 according to the patient's subjective opinions. Conclusions : This study shows the possibility that such medical treatment in Koreans can improve the rare idiopathic bilateral perspective among strabismus patients.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.7
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• pp.467-474
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• 2016

This study is intended to look into the effects of children's problem behaviors on the coping strategies of teachers involved in early childhood education (ECE). To achieve this, a survey was administered to 90 teachers involved in ECE at kindergartens and child care centers in Daejeon Metropolitan City. The findings showed that these teachers have a professionalism and suitability for their career and excellent ability to cope with the problems of children in this age group. The results showed that competent teachers had less tendency to put children in the corner or give physical punishment to them than incompetent teachers. Competent teachers didn't use coping strategies involving scolding or saying no with a somewhat loud voice, but rather pointed to each word accurately or helped the children express their feelings and understand their situation. However, their coping strategies may not always be suitable in all situations. When necessary, saying no accurately with an accompanying warning is also important. Consequently, career and professional knowledge are important for teachers involved in ECE, and it would be useful to collate the diverse strategies that they use.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.25 no.6
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• pp.469-476
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• 2012

In this paper, a finite element domain decomposition method using local and mixed Lagrange multipliers for a large scal structural analysis is presented. The proposed algorithms use local and mixed Lagrange multipliers to improve computational efficiency. In the original FETI method, classical Lagrange multiplier technique was used. In the dual-primal FETI method, the interface nodes are used at the corner nodes of each sub-domain. On the other hand, the proposed FETI-local analysis adopts localized Lagrange multipliers and the proposed FETI-mixed analysis uses both global and local Lagrange multipliers. The numerical analysis results by the proposed algorithms are compared with those obtained by dual-primal FETI method.

• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.12
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• pp.1923-1932
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• 2013

In order to solve the problem of severely distorted images from a wide-angle camera, we propose a calibration method which corrects a radial distortion in wide-angle images by estimation and validation of camera model. First, we estimate a camera model consisting of intrinsic and extrinsic parameters from calibration patterns, where intrinsic parameters are the focal length, the principal point and so on, and extrinsic parameters are the relative position and orientation of calibration pattern from a camera. Next we validate the estimated camera model by re-extracting corner points by inversing the model to images. Finally we correct the distortion of the image using the validated camera model. We confirm that the proposed method can correct the distortion more than 80% by the calibration experiments using the lattice shaped pattern images captured from a general web camera and a wide-angle camera.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.573-576
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• 2008

Recently, it is the well-known that there are some kinds of problem the waste concrete generated while repairing, reinforcing and dismantling of structures in the domestic and overseas. In this paper, various tests were performed about the use of the recycled concrete fine aggregate for the materials of high quality and structural concrete. And also, in order to improve structural performance of the concrete structure the steel frame was under overcrowded arrangement of steel bar. Consequently, it was be necessary the Self-Consolidating Concrete(SCC) that can fill the concrete into the work-form corner which has become overcrowded arrangement of steel bar without any other vibration. The purpose of this study is related to the properties of Self-Consolidating Concrete(SCC) according to mixing ratio of recycled concrete fine aggregate.