• Journal of the Korean Chemical Society
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• v.61 no.4
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• pp.143-150
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• 2017

Countercurrent oxidation process (COP) was developed and evaluated for treatment of highly concentrated PCB containing insulating oil. The PCB content in insulating oil taken from Haksanmetal company was found to be 1,512 ppm. The COP utilizes a self-sustained flame which propagates itself in a direction counter to the oxygen flow. The flame removes PCBs adsorbed in activated carbon and, at the same time, regenerates activated carbon. The flame temperature was determined from both mass loss of activated carbon and the relative ratio of CO and $CO_2$ exhausted during COP, and showed that its temperature lied in the range of $650-850^{\circ}C$. Removal efficiency of PCBs was achieved above 99.99% for 5% of insulating oil loaded activated carbon with 1 COP in weight ratio. Also, the same removal efficiency was acquired for 60% of insulating oil loaded activated carbon with three consecutive COP. In addition, specific surface area of activated carbon during COP was recovered to almost similar value of virgin activated carbon. It proved that the COP was much effective in removing high concentration of PCBs in insulating oil easily and affordably.

• Journal of the Ergonomics Society of Korea
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• v.36 no.4
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• pp.343-353
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• 2017

Objective: This study aims to evaluate the efficiency of two representative subway map design types, namely a diagram type and a geographical type using physiological metrics, performance metrics, and self-reported metrics, which are representative usability metrics. Background: Subway maps need to be designed in order for users to quickly search and recognize subway line information. Although most cities' subway maps currently use the diagram type designed by Henry Beck, New York City's subway map has recently been changed to the subway map type combined with the geographical type designed by Michael Hertz. However, not many studies on its efficiency are found, and the studies that are available mainly depend on questionnaire surveys or take on a subjective behavioral study type based on experts' experiences. In this regard, evaluation through a more objective method is needed. Method: This study employed usability metrics as a method to evaluate the efficiency of information search targeting the diagram type and geographical type subway maps used mostly as subway maps. To this end, physiological metrics obtained through eye tracking, task completion time, representative metric of task performance, and subjective evaluation metrics were used for the suitability evaluation of subway map designs. Results: In the result of gaze movement distance analysis, no significant difference was shown in the two design types in terms of a process finding a departure station from the starting point and a process finding a transfer station between the departure station and arrival station (destination). However, the gaze movement distance in the process finding the arrival station at the departure station was significantly shorter in the geographical type, rather than in the diagram type. The analysis of task completion time showed a result similar to the gaze movement distance analysis result. Task completion time was significantly shorter in the geographical type, rather than in the diagram type, which is in the process finding the arrival station at the departure station. In other information search processes, no significant difference was shown. As a result of subjective evaluation metrics analysis, no significant difference was revealed in the two design types. Conclusion: An analysis on the two representative subway map design types was carried out via the adoption of usability metrics. As a result, although no significant difference was shown in some information search processes, it was revealed that information search was easier in the geographical type overall. Also, it was found that usability metrics can be effectively used to evaluate the design types of subway maps. Application: The study results can be used to set design direction to offer ease in information search on subway lines. The study also can be used as a method to evaluate a subway map's design type.

• Journal of Arbitration Studies
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• v.27 no.2
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• pp.83-105
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• 2017

In contemporary society interest in and consumption of beauty treatment are increasing, raising interest in health and beauty. However, beauty-related laws are becoming factors of hindrance of beauty development. Currently the Public Health Control Act plays a basic role in the beauty art business in Korea, However the contents are in discord with international laws and its definition is not clear. Therefore it is causing conflicts of different occupations and job associations which are similar to art business. Especially, because neither definitions nor policies on beauty care devices exist in the Public Health Control Act, beauty care devices using in foreign countries cannot be used in Korea due to classification as medical devices. Under this circumstance, therefore, beauty care device uses by beauty artists violate the law. The government has tried to solve these irrational regulations. Recently, the Small and Medium Business Administration announced 'the improvement plan of small business and young founders site regulation for public economy recovery' in a ministerial meeting on December 28, 2016. Regulations on policy preparation for skincare devices were inclusive in this announcement. It is the question whether the regulations will be executed or not. Even though beauty industrial competitiveness was presented in the 18th Presidential Council on National Competitiveness in 2009, it was not practiced. The proposal bills for beauty law improvement have been put forth several times since 2000 including an improvement plan for regulating beauty care devices. However, so far there have been no improvements. The damage on the regulation classifying beauty devices as medical devices is not only restricted to skincare. This develops beauty devices and the beauty industry which imports and exports beauty devices. When beauty devices are exported, complicated procedures are unavoidable and when beauty devices are imported, irrational problems like reregistration procedures and costs occur. The reason why an improvement plan has not gone into practice is the resistance of the dermatologists' association. Dermatologists tend to stand positively against harming public health by saying that beauty devices used by beauty artists cause people to suffer side effects. In contrast, anyone who has a licence to use beauty devices is able to use them in foreign countries. It is not only infringement of one's right as a beauty artist but also people's right to receive beauty care services. With this reason, Korean's current law under which beauty devices are ruled as medical devices should be revised with accordance to domestic surroundings. Therefore in order to advance and globalize the beauty industry, the support and cooperation of the Korean government and relevant associations is needed to legislate and revise the beauty devices laws. The relevant associations abandon regional self-centeredness and cooperate to define ranges, size and management of beauty devices for safe use. If no collaboration exists, an arbitration agency should be established to solve the problem.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.9
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• pp.535-540
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• 2017

The changes in the electrical characteristics of CMOS ICs due to coupling with a narrow-band electromagnetic wave were analyzed in this study. A magnetron (3 kW, 2.45 GHz) was used as the narrow-band electromagnetic source. The DUT was a CMOS logic IC and the gate output was in the ON state. The malfunction of the ICs was confirmed by monitoring the variation of the gate output voltage. It was observed that malfunction (self-reset) and destruction of the ICs occurred as the electric field increased. To confirm the variation of electrical characteristics of the ICs due to the narrow-band electromagnetic wave, the pin-to-pin resistances (Vcc-GND, Vcc-Input1, Input1-GND) and input capacitance of the ICs were measured. The pin-to-pin resistances and input capacitance of the ICs before exposure to the narrow-band electromagnetic waves were $8.57M{\Omega}$ (Vcc-GND), $14.14M{\Omega}$ (Vcc-Input1), $18.24M{\Omega}$ (Input1-GND), and 5 pF (input capacitance). The ICs exposed to narrow-band electromagnetic waves showed mostly similar values, but some error values were observed, such as $2.5{\Omega}$, $50M{\Omega}$, or 71 pF. This is attributed to the breakdown of the pn junction when latch-up in CMOS occurred. In order to confirm surface damage of the ICs, the epoxy molding compound was removed and then studied with an optical microscope. In general, there was severe deterioration in the PCB trace. It is considered that the current density of the trace increased due to the electromagnetic wave, resulting in the deterioration of the trace. The results of this study can be applied as basic data for the analysis of the effect of narrow-band high-power electromagnetic waves on ICs.

• The Journal of Korean Academy of Prosthodontics
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• v.54 no.3
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• pp.218-225
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• 2016

Purpose: The purpose of this study was to evaluate the push-out bond strength of glass-fiber post cemented with different adhesive systems and surface treatments. Materials and methods: 160 tooth samples made from 48 human maxillary single-rooted teeth with similar root length were divided into 4 groups according to the adhesive system (no adhesive, Adper Single Bond 2, Clearfil SE Bond, Clearfil S3). Each group had 4 subgroups according to the post surface treatment methods (no treatment, sandblast, silane, sandblast and silane). Posts (Parapost Fiber White) were cemented with Rely X Unicem. The teeth were sectioned perpendicular to their long axis into 1-mm thick sections. The push-out tests was performed at a speed of 0.5 mm/min. The results were evaluated by 2-way ANOVA, 1-way ANOVA and multiple comparison procedures (Tukey test) (${\alpha}=0.05$). Results: Tukey test showed that the adhesive system significantly influenced the push-out strength. The Clearfil SE Bond group showed the highest value. Post surface treatments showed no significant effect. Conclusion: Bond strength of glass-fiber post cemented with self-adhesive resin cement using Clearfil SE Bond showed significantly higher values compared to other adhesive systems.

• The Journal of the Korea Contents Association
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• v.16 no.8
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• pp.107-116
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• 2016

This study aimed to provide the basic data to effectively teach nursery practices by investigating the dilemmas experienced by nursery school teachers-in-training majoring in children's welfare during nursery practicums and factors for solving such dilemmas. To this end, a qualitative analysis was conducted using journals, daily monitoring reports and interviews with 15 nursery school teachers-in-training in the Department of Social Welfare at S Women's University. The meaning related to the theme of the research was identified by repetitive reading in the process and then, the key words were determined through the categorization process. Next, the key words with similar concepts were re-classified and the sub-theme and the main theme were selected. In accordance with the analysis, it was identified that the dilemmas experienced during nursery practicums were related to tutors, children, classes, excessive work and the self. Furthermore, the subjects reported inner conflict because they had the alternative to select nursery or social welfare. The factors relieving such dilemmas included a change of children, encouragement from colleagues and the acquisition of practical knowledge. On the basis of the analysis results, this study proposed an approach to effectively implement nursery practicums for nursery school teachers-in-training majoring in children's welfare in the discussion chapter.

• Proceedings of the Korea Database Society Conference
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• 1999.06a
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• pp.175-186
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• 1999

Detecting the features of significant patterns from their own historical data is so much crucial to good performance specially in time-series forecasting. Recently, a new data filtering method (or multi-scale decomposition) such as wavelet analysis is considered more useful for handling the time-series that contain strong quasi-cyclical components than other methods. The reason is that wavelet analysis theoretically makes much better local information according to different time intervals from the filtered data. Wavelets can process information effectively at different scales. This implies inherent support fer multiresolution analysis, which correlates with time series that exhibit self-similar behavior across different time scales. The specific local properties of wavelets can for example be particularly useful to describe signals with sharp spiky, discontinuous or fractal structure in financial markets based on chaos theory and also allows the removal of noise-dependent high frequencies, while conserving the signal bearing high frequency terms of the signal. To date, the existing studies related to wavelet analysis are increasingly being applied to many different fields. In this study, we focus on several wavelet thresholding criteria or techniques to support multi-signal decomposition methods for financial time series forecasting and apply to forecast Korean Won / U.S. Dollar currency market as a case study. One of the most important problems that has to be solved with the application of the filtering is the correct choice of the filter types and the filter parameters. If the threshold is too small or too large then the wavelet shrinkage estimator will tend to overfit or underfit the data. It is often selected arbitrarily or by adopting a certain theoretical or statistical criteria. Recently, new and versatile techniques have been introduced related to that problem. Our study is to analyze thresholding or filtering methods based on wavelet analysis that use multi-signal decomposition algorithms within the neural network architectures specially in complex financial markets. Secondly, through the comparison with different filtering techniques' results we introduce the present different filtering criteria of wavelet analysis to support the neural network learning optimization and analyze the critical issues related to the optimal filter design problems in wavelet analysis. That is, those issues include finding the optimal filter parameter to extract significant input features for the forecasting model. Finally, from existing theory or experimental viewpoint concerning the criteria of wavelets thresholding parameters we propose the design of the optimal wavelet for representing a given signal useful in forecasting models, specially a well known neural network models.

• The Journal of the Korean dental association
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• v.48 no.5
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• pp.391-406
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• 2010

Orthodontic treatment for middle-aged patients has become more commonplace with various reasons including improved socioeconomic status. Understanding of oral status and treatment modalities of middle-aged patients is mandatory for accurate diagnosis and proper treatment planning. This study investigated 100 consecutive patients aged 40s and 50s and 100 aged 20s who had been examined and diagnosed at the Department of Orthodontics, Chonnam National University Dental Hospital. The results were obtained as follows; 1. Gender distribution showed female outnumbered male patients in young-aged adult patients, but middle-aged patients showed similar male and female distribution. 2. The major concern seeking orthodontic treatment was esthetics not only in young-aged but also in middle-aged adult patients, and a number of middle-aged patients were concerned about oral health as well. 3. Considerable number of middle-aged patients were referred by other dental specialties while young-aged adult patients were more self-motivated for orthodontic treatment. 4. Middle-aged adult patients had more missing teeth and periodontal disease than young-aged adults. 5. The most frequently-observed problem was dental spacing in middle-aged patients while dental crowding in young-aged adult patients. Middle-aged patients showed higher prevalence of deep overbite and overjet while most of young-aged adults presented opposite direction of problem in overbite and overjet. 6. Limited orthodontic treatment was required rather than comprehensive treatment in middle-aged patients, and the most common tooth moving area was anterior part of dentition in case of limited treatment. Need of interdisciplinary therapy with other dental specialties was more common in middle-aged patients. 7. Intervention of specific technique such as invisible TP, passive bracketing, passive wire bonding, and lingual orthodontics was more required in middle-aged patients. Considering that middle-aged patients have different characteristics than young-aged adults, the results of the present study suggest that different treatment modalities are required in middle-aged orthodontic patients in order to manage them properly and efficiently.

• Korean Journal of Occupational Health Nursing
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• v.7 no.1
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• pp.65-82
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• 1998

This study was carried out in order to confirm the reliability and validity of the commitment inventory developed by Meyer and Allen, and to investigate commitment level of health manager, to compare two different professionals of health manager such as industrial health nurse and industrial hygienist to find out some characteristics that have effect on commitment. This survey was done by self-administered questionnaire to 227 respondents as the trainees of Industrial Safety Training Center, KISCO from June to December 1996. Authors classified commitment into two categories ; professional commitment and organizational commitment, and these two types of commitments have three different aspects ; affective, continuance, and normative commitment based on Meyer's inventory. The results were as follows; 1. Items of whole scales of the both type of commitments have three factors that represent three aspects of commitment ; affective, continuance, and normative commitment. This means that each type of commitment was reliable to use as measurement tool of three different aspects of commitment. Classification of items by factor analysis was more consistent in professional commitment than organizational commitment. Among 16 items of organizational commitment, four items were classified into different aspects of commitment with similar factor loading. 2. Commitment level of industrial health nurse was higher than that of industrial hygienist in affective, continuance professional commitment controlled by other characteristics. These differences can be due to other characteristics of specific task and background of health managers that were not used in this study. 3. The level of affective professional commitment was statistically different in age, sex, educational level, and that of organizational commitment was statistically different in only two variables such as age, and job tenure. The level of continuance professional and organizational commitments were different in sex group, but past history of employment have effect on continuance organizational commitment. The level of normative organizational commitment was affected by only age. As the above results, the tools of measurement of commitment developed by Meyer and Allen can be useful to measure the level of commitment of health manager. Three aspects of two types of commitments were influenced by different characteristics of health manager. Authors suggested future study on the affecting variables to the commitment such as background, task of health manager and organizational characteristics.

• Journal of The Korean Society of Grassland and Forage Science
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• v.34 no.4
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• pp.234-239
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• 2014

This experiment was conducted to evaluate the effect of seeding rates on the forage quality and productivity of direct-seeded whole crop rice at the experimental field of the Grassland and Forages Division, National Institute of Animal Science, RDA from 2007 to 2008. Whole crop rice variety, "Nokyang", developed by the National Institute of Crop Science, was directly seeded with four different seeding rates (30, 60, 90 and 120 kg/ha). There were no significant differences (p<0.05) found in emergence date, heading date, greenish and disease resistance based on the seeding rates. Plant height increased at higher seeding rates but the tiller number per plant decreased (p<0.05). The dry matter (DM) content showed no significant difference based on seeding rates (p<0.05) while the yield of fresh and dry matter increased with incremented seeding rates (p<0.05). Acid detergent fiber (ADF) content increased with higher seeding rates, but the neutral detergent fiber (NDF) content did not show a similar tendency. The total digestible nutrient (TDN) content was lowest with 120 kg/ha seeding rate. The grain ratio decreased at higher seeding rates. In economic analysis, the plot seeded at a rate of 60 kg/ha showed the highest income increment. Although high seeding rates increased the DM yield, a seeding rate of 60 kg/ha is recommended as the proper seeding rate for direct-seeded whole crop rice.