• Journal of Magnetics
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• v.14 no.1
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• pp.47-51
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• 2009

The coreless linear synchronous motor (coreless LSM) has been widely used as a driving source of semiconductor production processes for machine speeding up, positioning accuracy and simple maintenance. However, this coreless LSM suffers the disadvantage of decreased thrust force created by the leakage of magnetic flux. With the goal of increasing the generated thrust force and decreasing the cogging force, the slot of the core part was removed and a moving-coil-type slotless LSM (moving-coil-type slotless LSM) is proposed in this paper. Although this moving-coil-type slotless LSM with a back-yoke at the primary side demonstrated an increase in the generated thrust force, it remained capable of generating the cogging force when the primary side was moved due to the position between the permanent magnet and the back-yoke. Therefore, we attempted to decrease the cogging force of the moving-coil-type slotless LSM. We found that the back-yoke length at the primary side needs to be made $0.5{\tau}$ longer than the integral multiple of the magnetic pole pitch in order to decrease the cogging force created by the moving-coil-type slotless LSM.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05c
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• pp.99-102
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• 2003

Tin dioxide thin films were deposited at $375^{\circ}C$ on alumina substrate by metal-organic chemical vapor deposition process to find the relationship between physicochemical properties and the annealing treatments. The small grains with heat treatments grew to the bunch of grains and then showed the hillocks on the film surface. The thickness decreased with annealing treatment. The measured binding energy (BE) and branching ratio of the Sn 3d spin-orbital doublet were typical of oxidized states of Sn and the BE of the O1s core level of about 530~530.65eV also confirmed the presence of O-Sn bonds. The BE of oxygen and tin with annealing treatment shifted to higher position. O/Sn atomic ratios of films deposited at $375^{\circ}C$ for 2min and 4min were 1.99 and 2.01, respectively. The value of the atomic ratio O/Sn of films deposited at $375^{\circ}C$ for 2min changed from 1.99 to 2.45 with annealing treatment. Gas sensitivity depended on annealing temperature, the sensitivity increased with increasing annealing temperature.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.11
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• pp.2073-2082
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• 2010

The 4-th generation of mobile communication aims to realize global, fast and mobile communication service. The satellite communication charges a key role in this field. In this study, an OTM(On-The-Move) antenna which is mounted on ground vehicles and is used for mobile communication between vehicle and satellite was addressed. Since vehicles move during communication, active antenna line-of-sight stabilization is a core technology to guarantee high satellite communication quality. Stabilization of a satellite tracking antenna which consists of 2-DOF gimbals, an elevation gimbal over an azimuth gimbal, was considered in this study. Various disturbance torques such as static and dynamic mass imbalance torques, variation of moment of inertia according to elevation angle, friction torque related to vehicle motion, equivalent disturbance torque due to antenna roll motion, etc. were analyzed. As a robust stabilization control, rate feedback with sliding mode control and position feedback with proportional+integral control was suggested. To compensate antenna roll motion, a supplementary roll rate feed forward control was included beside of the feedback control loop. The feasibility of the analysis and the proposed control design were verified along with some simulation results.

• Journal of Elementary Mathematics Education in Korea
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• v.18 no.3
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• pp.425-439
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• 2014

The concept of a fraction as division is a core idea which serves as a axiom in the process of a extension of the natural number system to rational number system. Also, it has necessary position in elementary mathematics. Nevertheless, the timing and method of the introduction of this concept in Korean elementary math textbooks is not well established. In this thesis, I suggested a solution of a various topics which is related to this problem, that is, transforming improper fraction to mixed number, the usage of quotient as a term, explaining the algorithm of division of fraction, transforming fraction to decimal.

• The Korean Journal of Archival Studies
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• no.65
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• pp.47-88
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• 2020

Moon Jae-in as the government was launching new records & Archives management innovation is promoted. It was necessary to overhaul the Presidential Records & Archives Act and resolve the issues so far. The key issues include the establishment of individual presidential archives and the guarantee of access to former presidents. The current administration of presidential records is being carried out in the position of a manager (agency). The system's biggest "customers" are discussing management difficulties, even though they are former presidents. Record management should be a customer-centered information service. The "core customer" of managing presidential records is the former president. Another important problem is to separate the Presidential Archives from the National Archives to strengthen its status.

• Journal of International Academy of Physical Therapy Research
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• v.10 no.2
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• pp.1779-1784
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• 2019

Background: A number of researchers have attempted to improve the balance of stroke patients, however there is still a question as to whether taping is effective in increasing balance. Objective: To determine the effect of paretic and non-paretic side taping on the balance ability in patients with stroke. Design: A single-blind randomized controlled trial Methods: This randomized single-blind controlled clinical trial with a repeated measures study included 45 subjects who were randomly assigned to paretic side taping groups (n=15), non-paretic side taping groups (n=15), and trunk exercise groups (n=15). Trunk exercise and paretic side taping groups had taping on the paralyzed erector spinae, while the non-paretic side taping group had taping on the non-paralyzed erector spinae. Trunk exercises were performed for 30 minutes to promote core muscles. The balance ability measured the center of pressure movement (paretic side, non-paretic side,forward, backward, limit of stability) in the sitting position. All measurements were evaluated using BioRescue. Results: All three groups showed significant increase in all variables after 4 weeks. The paretic and non-paretic side taping groups had a significant increase in all variables after 30 min of attachment. However, there was no significant difference among the three groups. Conclusions: Paralysis and non-paralysis taping improved the balance ability of patients with stroke in an immediate effect of 30 min. However, after 4 weeks of intervention, taping with trunk exercise did not differ from single trunk exercise. In future studies, various analyses need to be conducted through more diverse evaluations.

• Safety and Health at Work
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• v.1 no.1
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• pp.43-50
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• 2010

Objectives: The objective of this study was to investigate the effect of chain installation condition on stress distribution that could eventually cause disastrous failure from sudden deformation and geometric rupture. Methods: Fractographic method used for the failed chain indicates that over-stress was considered as the root cause of failure. 3D modeling and finite element analysis for the chain, used in a crane hook, were performed with a three-dimensional interactive application program, CATIA, commercial finite element analysis and computational fluid dynamic software, ANSYS. Results: The results showed that the state of stress was changed depending on the initial position of the chain that was installed in the hook. Especially, the magnitude of the stress was strongly affected by the bending forces, which are 2.5 times greater (under the simulation condition currently investigated) than that from the plain tensile load. Also, it was noted that the change of load state is strongly related to the failure of parts. The chain can hold an ultimate load of about 8 tons with only the tensile load acting on it. Conclusion: The conclusions of this research clearly showed that a reduction of the loss from similar incidents can be achieved when an operator properly handles the installation of the chain.

• Cross-Cultural Studies
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• v.35
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• pp.35-58
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• 2014

This article aims to explain the 'people-image' of Bakhtin's works in the light of "Transgredience" and "Transition." According to Bakhtin, the real core of every culture is the people. But he did try to answer the question "what is the people?" I think, the secret of Bakhtinian thought is located in the people-image, because it is the one of the territories that have not been explained. For this purpose, we have to examine four images represented by Bakhtin, - rogue, clown, fool, thief. These images are the concrete and individualized images of people, who can characterize the power of transgredience and transition. They commonly act for changing ordinary borders of identities formulated with nationality, property, status, classes, sex and so forth. In this sense, Bakhtin thinks that the masks are the real nature which can show the mutational power of Being. That is the kernel of Bakhtin's people-image that makes and changes every cultural world. When we accept and practise this perspective positively, we will realize that Bakhtin's position is close to the cultural politics, because a practical power of thought cannot help but being political. That's why we have to investigate Bakhtin's people-image from a vantage point of "Transgredience" and "Transition."

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.05a
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• pp.734-737
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• 2014

With the advent of smart age, the concern on smart work has gradually increased in the situation that creative innovation capability has become one of the important elements in business competitiveness. Most domestic small and medium-sized businesses have partly introduced smart work system due to the lack of its recognition and understanding about a specific method to implement. Under the environment, it is essential to make standardization strategy and do systematic implementation for core technology which leads global market in order to secure the dominant position in smart work related technologies. Therefore, this paper suggests standardization items which lead global standard and implementation direction on standardization through analysing the current situation introducing smart work in small and medium-sized business and technology/standardization trends.

• Journal of Positioning, Navigation, and Timing
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• v.11 no.4
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• pp.229-238
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• 2022

This paper addresses on the International technical trends, standards, and development status of terrestrial radionavigation system to provide more accurate and fail-safe Positioning, Navigation, and Timing (PNT) Information available in maritime navigation environment. We analyze the performance result of pilot service in enhanced Long range navigation (eLoran) testbed environment using Low Frequency (LF) signal, and describe the development status of Ranging-Mode (R-Mode) system using Medium Frequency (MF) and Very High Frequency (VHF) to meet the Harbor Entrances and Approaches (HEA) requirement of International Maritime Organization (IMO) within 10m position accuracy. Furthermore, we present an architecture for integrated service of satellite-terrestrial navigation system and future maritime applicable fields. As the core information infrastructure of future navigation for 4th industrial revolution, this paper will be contributed to determining the direction of present and future to provide fail-safe PNT service with Global Navigation Satellite System (GNSS) based on the technical enhancement of terrestrial integrated navigation system.