• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.3
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• pp.526-531
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• 2016

This paper presents an experimental study on the optimal settings for the selected DC fault relay (50F) to improve the operating performance for the high-speed circuit breaker on DC feeding system which ensure safety within rolling stock maintenance depot. In this study, current supplied to overhead contact wire was calculated on 1 ms interval to analyze the correction values of DC fault selective relay for the operation of current supply cutout. Particularly, standards for the accurate detection of accidents between an electric railway vehicle and the electric power facilities are shown by investigating the optimal correction values for detection of fault current, and the results indicated that it takes about 213 ms for the DC fault selective relay(50F) to fully open. In the future, the correction values of DC fault selective relay suggested in this paper will be used as the reference values of protective relay for the safe operation of DC electric railroad system such as urban railway.

• Korean Institute of Interior Design Journal
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• v.21 no.6
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• pp.177-185
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• 2012

The endowed privilege to an established profession acts as an important motivation related to professionalization of occupations. The established profession enjoys cognitive, legal, and economic privilege. This study analyzes the professionalization process of interior design. Specifically, the study evaluates the suitability of the body of knowledge and professional ethos(i.e., protection of citizen's health, safety, and welfare), while analyzing the professionalization of interior design in the United States. The research aims at proposing a reference point for the professionalization of Korean interior design. Utilized data include research paper, court sentencing, and reports published by related professional organizations. The study concludes that 3E's are a means of professionalization of interior design, while separating interior design from interior decorating. In addition, there is no evidence to the protection of citizen's HSW. Rather, it increases service costs and restricts the job opportunities. When the public is not persuaded, the argument related to the necessity of license for the protecting citizen's HSW can be consumed as a mere rhetoric, concealing intentions for formulating a cartel. Thus, this study proposes that the professionalization of interior design may focus on the establishment of identity and body of knowledge, which are specific to interior design.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.53 no.4
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• pp.213-223
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• 2004

In the machine tool industry, direct drive linear motor technology is of increasing interest as a means to achieve high acceleration, and to increase reliability. The advantages of such a motor are that it has a good linearity and has no need of such mechanical energy conversion parts, which change rotary motion into linear motion, as screws, gears, chains etc In this paper, two structures of LOA are analyzed. One is the moving-coil type LOA and the other is moving-magnet type LOA. Two types of LOA are analyzed, with reference to the following parameters as variables: magnetic field, flux linkage, motor thrust and back emf. These variables are derived by the use of analytical method in terms of two-dimensional rectangular coordinate system. The maximum values of thrust according to such design parameters as air-gap length and magnet height for each model is also represented. The results are validated extensively by comparison with finite element method. In particular, we experiment moving-coil LOA which is already manufactured and confirm that the experimental results are shown in good agreement with analysis through the comparison of between analytical and experimental results

• The Journal of Fisheries Business Administration
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• v.47 no.1
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• pp.63-86
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• 2016

The purpose of this study is to investigate production efficiency of Oceans and Fisheries Human Resources Development Programs Efficiency using Bootstrap-DEA. The study extracts 33 officials curriculum, 11 fisheries managers curriculum for its analytical. First, the study estimates technical, pure technical, and scale efficiency of each curriculums based on traditional DEA under the assumption of CRS and VRS. 8(official 7, managers 1) curriculums are identified as efficient DMUs under the CCR-model, and 13(official 10, managers 3) under the BCC-model. We provide inputs that allow inefficient curriculum to be efficient DMUs on a production frontier, and a reference set for their bench-marking. Second, rank test, Wilcoxon-Mann-Whitney test to find a statistical significance of heterogeneity existing in efficiences between Bootstrap-DEA tenical vs Bootstrap-DEA pure technical was no significant difference. We have identified that G10, 11, 12 13, 25, 31, 33, 39 curriculums are the most efficiently produced in the technical and pure technical efficiency. Also we managed to measure the inefficiency which exists in efficiently produced curriculums when estimating the bias corrected efficiency scores. In Technical efficiency, Operation and facility was significant at the 10%. In Pure technical efficiency, facility was significant at the 10%.

• Advances in concrete construction
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• v.4 no.2
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• pp.89-105
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• 2016

The post - fire investigation is conducted on a fire-affected reinforced concrete shear wall building to ascertain the level of its strength degradation due to the fire incident. Fire incident took place in a three-storey building made of reinforced concrete shear wall and roof with operating floors made of steel beams and chequered plates. The usage of the building is to handle explosives. Elevated temperature during the fire is estimated to be $350^{\circ}C$ based on visual inspection. Destructive (core extraction) and non-destructive (rebound hammer and ultrasonic pulse velocity) tests are conducted to evaluate the concrete strength. X-ray diffraction (XRD) and Field Emission Scanning Electron Microscopy (FESEM) are used for analyzing micro structural changes of the concrete due to fire. Tests are conducted for concrete walls and roof slab on both burnt and unburnt locations. The analysis of test results reveals no significant degradation of the building after the fire which signifies that the structure can be used with full expectancy of performance for the remaining service life. This document can be used as a reference for future forensic investigations of similar fire affected concrete structures.

• Journal of the Ergonomics Society of Korea
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• v.30 no.1
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• pp.9-17
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• 2011

Consumer products are produced on the premise that consumers can use their products safely and effectively no matter how serious human errors they may make. However, different careers and educational experiences of them may induce diverse human errors when they want to use them. In that sense, not a few policies to reduce human errors may show some implications for human error prevention and industrial design of consumer products. In this paper, producers' safety efforts required by Product Liability(PL) Act were reviewed in view of human error prevention, and legal aspects of manufacturers' responsibility for consumer products were discussed in relation to Product Liability Act. Then, principal approaches for them were introduced under the title of System Safety Precedence. After that, major key points for preventing human errors related with consumer products - such as ergonomic design and effective labeling - were discussed with reference to ISO standards. Therefore, it was shown that all the efforts required by PL Act would be correspondent to human error prevention in the whole manufacturing processes if understood by ergonomists. To make a conclusion, it could be said that, for human error prevention, the principle of System Safety Precedence would be indispensable, and that all the efforts for preventing human errors should be systematically organized in Product Safety Management Systems.

• Spatial Information Research
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• v.17 no.3
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• pp.351-359
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• 2009

Nowadays, a precision multiple-beam epoch sounder is a depth-sounding apparatus, which is widely used especially for the mapping of bottom of the sea in the coastal area and the bed of river. However, there has been no attempt to verify the accuracy of the depth-sounding apparatus with the data obtained through the actual measurement. As a consequence, the efficient and systematic evaluation of the survey results cannot be performed. In this paper, the accuracy of the multiple beam echo sounder is analyzed by comparing the in-situ measurements and reference data. The test results show that the highest level of accuracy, indicated by IHO, can be achieved even though the magnitude of error increases with the depth of water.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.26 no.2
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• pp.7-17
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• 1996

This study was performed to determine the postitional relationships of two lobes of parenchyma and to analysis the anatomical feature and its variations of duct on the panoramic views of the normal parotid glands in adults. Materials included 66 panoramic views and anterioposterior views of sialograms of selected persons and the radiograms of the gland experimentally reproduced on dry skull with lead foil and the reference images of computed tomograms of normal persons. Results were as follows : 1. On panoramic view of sialogram, the superficial lobe was revealed with totally being superimposed with the mandibular ramus and condyle and its tail portion superimposed with mandibular angle area, the deep lobe was revealed between the posterior border of the ramus and the mastoid process, and the isthmus was begin from the marked furcation off main duct and superimposed partially with the medial part of the deep lobe. 2, The mean length and the lateral extension of parenchyma was 63.18±8.05mm and 21.78±4.87mm respectively on panoramic view and showed no statistical relationship between them. 3. The main duct was generally perpendicular to the posterior border of ramus at middle portion and its configurations revealed 57,58％ of curvilinear type, 21.21％ sigmoid type, 15.15％ reverse sigmoid type. 4, The interlobular ducts of the deep lobe showed relatively well defined features between the mandibular ramus and the mastoid process.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.28 no.1
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• pp.37-46
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• 1998

The purpose of this study was to evaluate the diagnostic performance of the senior dental students for the proximal dental caries on intraoral radiographs and to compare it with the dental hospital residents, the reference group. It was also investigated the diagnostic performance according to the carious lesion depth. Thirty-five intraoral periapical and bitewing radiographs with 213 proximal surfaces included in this study were selected from the dental patients at Chonnam National University Hospital. The observers were 181 senior dental students from 5 dental schools and 40 dentists who were second year resident from 5 dental hospitals. They were asked to evaluate the presence or the absence of the proximal dental caries. The results were as follows: 1. The mean of the hitting rate for the overall observers was 184.51 surfaces and the diagnostic accuracy was 86.62％. 2. The diagnostic performance of the sound proximal tooth surfaces was very high, i.e., 91.5％ true negative rate and 8.5％ false positive rate. 3. The diagnostic performance of the dentist group was higher than the student group(P<0.05). 4. The proximal dental caries perceptibility increased as the lesion depth increased significantly(P<0.001) except no difference between the carious lesion depth III and IV (P>0.001).

• Journal of IKEEE
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• v.19 no.2
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• pp.160-167
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• 2015

We present an experimental implementation of the inexpensive microwave security sensor that can detect both static and slowly moving objects in cluttered environment. The prototype consists of a frequency-modulated continuous wave radar sensor, control board or computer and software. The prototype was tested in a cluttered indoor environment. In case of intrusion or change of environment the sensor will give an alarm, determine the location of new object, change in its location and can detect a slowly moving target. To make a low-cost unit we use commercially available automotive radar and own signal processing techniques for object detection and tracking. The intruder detection is based on a comparison between current 'image' in memory and 'no-intrusion' reference image. The main challenge is to develop a reliable technique for detection of a relatively low-magnitude object signals hidden in multipath clutter echo signals. Various experimental measurements and computations have shown the feasibility and performance of the system.