• The Journal of Korean Society for School & Community Health Education
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• v.18 no.1
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• pp.99-110
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• 2017

Objectives: The purpose of this study was to examine the effect of the field practice of health science majors on their career attitude maturity in our country in an effort to determine influential factors. Methods: The subjects in this study were 220 selected health science majors in three different colleges located in North Gyeongsang Province and South Chungcheong Province. A survey was conducted with structured questionnaires from September 1 to 10, 2016. As for statistical analysis. a statistical package SPSS 20.0 was used. Results: The factors of the field practice of the health science majors that affected their career attitude maturity were the career of people in charge(${\beta}=.145$, p-.034) and the content of field practice(${\beta}=.233$, p=.015), which were the factors of the institution for field practice, and the relationship between people in charge and trainees(${\beta}=.299$, p=.008) and satisfaction with field placement(${\beta}=-.262$, p=.013) that were the factors of field practice tasks were also influential. The influence of these factors were statistically significant. Conclusions: Institutions that provide health science majors with the opportunity of field practice should try to improve the competencies of people in charge, to ensure the substantiality of field practice in content and to develop standardized manuals for field practice. In schools, professors who are in charge of field practice should offer intensive guidance and feedback on problems with field practice. These efforts are expected to elevate the career attitude maturity of students.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.22 no.2
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• pp.278-288
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• 1998

An efficient and useful method to improve the local stress field in a displacement-formulated finite element solution has been proposed using the theory of conjugate approximations for a stress field and the Loubignac's iterative method for a displacement field. Validity of the proposed method has been tested through three test examples, to improve the stress field and displacement field in the whole domain and the local regions. As a result of analysis on the test examples, it is found that the stress field in the local regions are approximated to those in the whole domain within a few iterations which have satisfied the original finite element equilibrium equation. In addition, it is found that the local stress field are by far better approximated to the exact stress field than the displacement-based stress field with the reduction of the finite-element mesh-size.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.1752-1761
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• 2000

This paper describes the far-field estimation using the near-field measurement data. Measurement in far-field region gives us the acoustical characteristics of the source but in general measurement is made in near-field such as acoustic water tank or anechoic chamber, so far-field acoustical characteristics of the source should be predicted from near-field data. In this case, the number of measurement points in the near field which relates to the accuracy of the predicted field and the amount of data processing, should be optimized. Existing papers say that measurement points is proportional to kL and depends on geometry and directivity of the source. But they do not give us any definite criterion for the required number of measurement points. Boundary Collocation Method which is one of the far-field prediction methods, is analyzed based on Helmholtz integral equation and Green function and it has been found that the number of measurement points is optimized as 0.54kL which is about one half of the existing results.

• Journal of Drive and Control
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• v.17 no.4
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• pp.103-112
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• 2020

Field robots are used in various fields, such as agriculture, forestry, manufacturing, and construction; their use has recently expanded to include submarine areas. Field robots can aid in various tasks, such as soil transport, ground clearance, and dismantling of buildings. As field robots are used in a variety of different areas, the difficulty of the work is also quite varied. Increased difficulty is associated with an increased risk of accidents involving the field robot. In order to reduce the accident rate of field robot workers, the need for digitalization and automation of field robots is becoming more of an issue. To this end, it is necessary to study a system that enables workers to do their work without directly contacting a field robot. Therefore, in this paper, we introduce a control system for wireless remote control of a small field robot. The field robot can be wirelessly controlled by a worker in a remote location if the worker cannot be present at the work site. The implemented remote system is tested according to the type of work, and the operating characteristics of the remote system are assessed.

• Journal of the Korean Applied Science and Technology
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• v.30 no.4
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• pp.586-591
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• 2013

This paper describes the characteristics of thermo-field emission in a freestanding silicon nanomembrane under ion bombardment with various thermal and field conditions. The thermal effect and field effect in thermo-field emission in silicon nanomembrane are investigated by varying kinetic energy of ions and electric field applied to the silicon nanomembrane surface, respectively. We found that thermo-field emission increases linearly as the electric field increases, when the electric field intensity is lower than the threshold. The thermo-field emission (schottky effect) increases proportionally to the power of temperature, which agree well with the predictions of a thermo-field emission model.

• Progress in Superconductivity and Cryogenics
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• v.14 no.3
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• pp.18-22
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• 2012

This paper presents the magnetic field analysis of the racetrack double pancake field coil for the 10 MW class superconducting wind turbine which is considered to be the next generation of wind turbines using the 3 Dimensional FEM(Finite Elements Method). Generally, the racetrack-shaped field coil which is wound by the second generation(2G) superconducting wire in the longer axial direction is used, because the racetrack-shaped field coil generates the higher magnetic field density at the minimum size and reduces the synchronous reactance. To analysis the performance of the wind turbines, It is important to calculate the distribution of magnetic flux density at the straight parts and both end sections of the racetrack-shaped high temperature superconductivity(HTS) field coil. In addition, Lorentz force acting on the superconducting wire is calculated by the analysis of the magnetic field and it is important that through this way Lorentz force can be used as a parameter in the mechanical analysis which analyzes the mechanical stress on the racetrack-shaped field coil.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.04a
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• pp.916-919
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• 2008

This paper deals with a means to reproduce sound field by using Kirchhoff-Helmholtz integral equation. We control boundary value or generate sound sources on the boundary in order to control the sound field as we want. The method assumes that there is a unique relation between sound field and its boundary should. Otherwise the reproduced sound field is different from what we want generate; the original sound field. Half-infinite sound field and finite sound field are considered and whether the uniqueness is hold or not and how the reproduced field is generated are discussed in each case.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.51 no.11
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• pp.616-621
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• 2002

With biological effects by ELF (Extremely Low Frequency) magnetic field generated from power system, the transient magnetic field from electric appliances is a major issue presently. Because the transient magnetic field induces higher current than the power frequency field inside living bodies, transient magnetic field exposure has been much focused. In this paper, it is shown that transient magnetic field from electric home appliances can be characterized as magnetic dipole moment. In this method, the dipole moment vector is assumed by allowing an uncertainty of 6dB in the estimated field. A parameter M that represents biological interaction was applied also. The proposed method was applied to 7 types of appliances (hair drier, heater, VDT, etc.) and their equivalent magnetic dipole moment and harmonic components were estimated. As the results, the useful data for quantifying magnetic field distribution around electric appliances were obtained.

• The Bulletin of The Korean Astronomical Society
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• v.35 no.2
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• pp.49.2-49.2
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• 2010

In order to understand the configuration of magnetic field producing a solar penumbral microjet that was recently discovered by Hinode, we performed a magnetohydrodynamic simulation reproducing a dynamic process of how that configuration is formed in a modeled solar penumbral region. A horizontal magnetic flux tube representing a penumbral filament is placed in a stratified atmosphere containing the background magnetic field that is directed in a relatively vertical direction. Between the flux tube and the background field there forms the intermediate region in which the magnetic field has a transitional configuration, and the simulation shows that in the intermediate region magnetic reconnection occurs to produce a clear jet- like structure as suggested by observations. The result that a continuous distribution of magnetic field in three-dimensional space gives birth to the intermediate region producing a jet presents a new view about the mechanism of a penumbral microjet, compared to a simplistic view that two field lines, one of which represents a penumbral filament and the other the background field, interact together to produce a jet. We also discuss the role of the intermediate region in protecting the structure of a penumbral filament subject to microjets.

• Journal of the Korean Vacuum Society
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• v.8 no.2
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• pp.172-179
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• 1999

The axial distributions of plasma density in a helical resonator plasma with the external magnetic field have been measured using Langmuir probes. Net RF power is set to 200W and chamber pressure is varied from 0.4 mTorr to 100mTorr there are three kinds of eternal magnetic field structure applied on the helical resonator plasma. One is a uniform magnetic field, the second is a positive gradient magnetic field and the third is a negative gradient magnetic field. In the three magnetic field structures, the negative gradient magnetic field is found to show the highest increase in plasma density on the substrate compared with other magnetic structures. Plasma density profile in helical resonator is well consistent with electromagnetic field pattern obtained by computer simulation. It is also found that axial magnetic fields do not affect plasma density distribution in the plasma reactor region, but induce the increase of plasma density in the process chamber region. In order to avoid the nonuniformity of radial density profile, weak magnetic fields under 100G are applied.