• Journal of the Korean Society for Precision Engineering
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• v.31 no.6
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• pp.535-541
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• 2014

In this research, three degree-of-freedom parallel spherical robot is developed for an artificial eyeball. The proposed system is comprised of a moving and a base plate, three prismatic actuators, and a ball joint for an angular movement of the moving plate. The vector analysis is employed to investigate the relationship between positions of the actuators and a pose of the moving plate. The required ranges for every actuators are calculated using the derived inverse kinematics in regard to the combination of two different levels for the size of the system component. Then the size of every components is determined from the analyzed trend. PI controller is employed for the position control of the moving plate. Finally the proposed system is verified using an arbitrary path of the angular movement.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.6
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• pp.810-812
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• 2014

In this paper, a hagwon-bus boarding danger warning system based on computer vision is proposed to protect children from an accident causing injuries or death. Three zones are defined and different algorithms are applied to detect moving objects. In zone 1, a block-based entropy value is calculated using the absolute difference image generated by the absolute differential estimation between background image and incoming video frame. In zone 2, an effective and robust motion object tracking algorithm is performed based on the particle filter. Experimental results demonstrate the efficient and effectively of the algorithm for moving object inspection in each zone.

• Proceedings of the KIEE Conference
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• 2006.10a
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• pp.180-181
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• 2006

In this paper, there have been brief review about the important consideration in laboratory planning and construction of the reliability assessment infrastructure including 400 kV, 120 kVA AC test system, which enable to evaluate the HV long-term overcharged withstand performance for spacers using in Gas Insulated Switchgears up to transmission class, Also it is described simply about its trial running of the whole test system and its assessment example. To inform the founded national code, RS C 0084, and the procedure for getting a reliability assessment certificate issued by the government, brief description of the code and summation of test results have been conducted.

• Journal of Christian Education in Korea
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• v.75
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• pp.7-31
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• 2023

Purpose of study: The purpose of this essay is to seek an alternative direction for confirmation education within the context of Korean Protestant Church, addressing the following issues: 1) Confusion in the use of terminology on confirmation, 2) Superficial understanding of confirmation, and the absence or privatization of confirmation theology, 3) Formalized confirmation education based on the concept of rites of passage, and 4) The absence of denominationally structured confirmation education. Research content and method: To achieve this purpose, this essay attempts to foster an intradisciplinary and interactive dialogue on confirmation through a biblical, historical, and theological approach. Biblically, confirmation is to be understood as the unity of the baptism of water and the baptism of Holy Spirit, associated with the consecration of the baptized as royal priests through the baptism of Holy Spirit. Historically, as a part of the rite of Christian initiation, confirmation was a unified rite that has undergone a process of separation and reunification. Theologically, the rite of confirmation affirms the covenant of the Triune God given in baptism and is positioned between baptism and the Lord's Supper. Conclusions and Suggestions: In conclusion, this essay suggests an alternative form of Confirmation education that is oriented towards the following objectives: 1) Education that forms the identity given in the baptismal covenant, 2) Education that reflects characteristics of both baptism and the Lord's Supper, 3) Education that integrates the Bible, doctrine, and life of confirmand and, 4) Education based on an organic educational system.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.2
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• pp.165-171
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• 2012

In this paper, an analytical method is used to perform a sensitivity analysis of geometric errors in a three-axis machine tool. First, an error synthesis model is constructed for evaluating the position volumetric error due to the geometric errors, and then an output variable is defined, such as the magnitude of the position volumetric error. Next, the global sensitivity analysis is executed using an analytical method. Finally, the sensitivity indices are calculated using the quantitative values of the geometric errors.

• Journal of the Korean Magnetics Society
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• v.8 no.3
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• pp.125-130
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• 1998

13Cr-1.5Nb-Fe alloy powder was fabricated by water atomization method, and ring-shape specimen of this composition was fabricated by oil press, and then sintered in the vacuum furnace. Powder shape, size distribution, composition (C, N, O, S) analysis and saturation magnetization of as-prepared 13Cr-1.5Nb-Fe alloy powder were investigated. Ac permeability and power loss was measured after forming and sintering process. Saturation magnetization and contents of oxygen of the alloy powder is160 emu/g and about 6000 ppm, respectively. 50 % volume fraction indicate particle size of 70$\mu$m. The ac permeability of sintered specimen increases with increasing sintering temperature and forming pressure. The power loss is 107 W/cc at sintering temperature of 1200 $^{\circ}C$, 12 ton/$\textrm{cm}^2$ forming pressure, and 20 KHz. It is the lowest among the prepared specimen.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.5
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• pp.38-45
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• 2004

As optical communication is being substituted for telecommunication, the demand of a large variety of fiber optic components is increasing. V-groove substrates, one of the module components, are used to connect optical fibers to optical planar circuits and to arrange fibers. Their applications are multi-channel optical connectors and optical waveguide fiber coupling, etc. Because these substrates are a critical part of the splitter in a multiplexer and a multi fiber connector, precise and reliable fabrication process is required. For precisely aligning core pitch between fibers, machined core pitch tolerance should be within sub-microns. Therefore, these are generally produced by state-of-the-art micro-fabrication like MEMS. However, most of the process equipment is very expensive. It is also difficult to change the process line for custom designs to meet specific requirements using various materials. For various design specifications such as different values of the V angle and low-priced process, the fabrication method should be flexible and low cost. To achieve this goal, we have suggested a miniaturized machine tool with high accuracy positioning system. Through this study, it is shown that this cutting process can be applied to produce V-groove subtracts. We also show the possibility of using a miniaturized machining system for producing small parts.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.8 no.2
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• pp.356-364
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• 1998

The dependence of green and sintered densities of Zirconia-Toughened Alumina ($ZTA:\;Al_2O_3/\;15\;vol{%}\;ZrO_2$) on the properties of spray-dried granules was studied thoroughly to establish the optimum compaction condition leading to high reproducibility in the light of sintered density. The sphericity, mean size, degree of hollow occurrence and moisture content of spray-dried granules were largely different in between the granule containing binder and the ones with no binder. The effect of these differences in the characteristic of granules on the compaction behavior was examined in terms of the compaction pressure from 80 MPa to 120 MPa 10 MPa increment and the compaction method, i.e., uniaxial and cold isostatic pressing. This work confirmed that the reproducibility of sintered density caused by the variation of granule property could be improved by the optimization of compaction process. The variation of sintered density was controlled within 1 % deviation by compacting the granules under a relatively low pressure of 80 MPa in an uniaxial forming and subsequent cold isostatic pressing at high pressure of 500 MPa.

• Journal of Technologic Dentistry
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• v.45 no.1
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• pp.1-7
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• 2023

Purpose: To evaluate the marginal and internal fit of metal coping fabricated by a metal three-dimensional (3D) printer that uses selective laser melting (SLM). Methods: An extraoral scanner was used to scan a die of the prepared maxillary right first molar, and the coping was designed using computer-aided design software and saved as an stereo lithography (STL) file. Ten specimens were printed with an SLM-type metal 3D printer (SLM group), and 10 more specimens were fabricated by casting the castable patterns output generated by a digital light processing-type resin 3D printer (casting the 3D printed resin patterns [CRP] group). The fit was measured using the silicon replica technique, and 8 points (A to H) were set per specimen to measure the marginal (points A, H) and internal (points B~G) gaps. The differences among the groups were compared using the Mann-Whitney U-test (α=0.05). Results: The mean of marginal fit in the SLM group was 69.67±18.04 ㎛, while in the CRP group was 117.10±41.95 ㎛. The internal fit of the SLM group was 95.18±41.20 ㎛, and that of the CRP group was 86.35±32 ㎛. As a result of statistical analysis, there was a significant difference in marginal fit between the SLM and CRP groups (p<0.05); however, there was no significant difference in internal fit between the SLM group and the CRP group (p>0.05). Conclusion: The marginal and internal fit of SLM is within the clinically acceptable range, and it seems to be applicable in terms of fit.

• Journal of Christian Education in Korea
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• v.75
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• pp.153-170
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• 2023

Purpose of study: This study seeks practical ways to resolve conflicts between church and religious community members in modern society living in an age of division and conflict. Research content and method: First, the phenomenon and causes of a society of division and conflict were examined. Second shalom was studied to restore division and conflict. Third values were discovered along with the ABCD theory for the development of an asset-based community in order to solve a society of conflict with shalom. 4D cycle strategy of A.I. Fourth in order to restore the conflicts of the faith community to shalom, the ABCD theory and the 4D of A.I. were presented with ways to manage conflicts, minimize division, and restore shalom through dialogue and storytelling tools. Conclusions and Suggestions: The various conflicts in our society can be restored when all Christians discover their vocation and talent through the method of dialogue for shalom, solidarity as a community of faith, and achieve shalom. Therefore it is necessary to educate the Shalom faith community through dialogue for Shalom.