• Journal of the Korean Ceramic Society
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• v.39 no.6
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• pp.582-588
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• 2002

IrO$_2$-RuO$_2$ films were deposited on plasma sprayed TiO$_2$ buffer layer above Ti metal by sol-gel and dip-coating method. Organic vehicle (ethyl cellulose and $\alpha$-terpineol) and glass frit were added to improve adherence of the coatings. Taguchi method and L$_{18}$ (2$^1$$\times$3$^{7}$ ) orthogonal arrays were evalvated in terms of current density to determine the optimal combination of levels of factors that best satisfy the bigger is better quality characteristic. The observed conditions were as fellows: ethyl cellulose (100 cp), drying temperature and time (17$0^{\circ}C$,20 min), heat treatment temperature and time (75$0^{\circ}C$,10 min), the weight ratio of IrO$_2$-RuO/powders to glass frit (99:5), final heat treatment time (120 min) and flow rate of air (5 sccm), respectively. ANOVA analysis suggested that the influence of the factors within $\alpha$= 0.1 was significant with a 90% confidence level.

• Journal of Korean Society of Forest Science
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• v.8 no.1
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• pp.11-16
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• 1968

1. A Study was to delineate the correlation relationship growth factors, a) height and clear-length, b) height and circle of breast height, c) height and circle of ground height, d) height and crown length, of phyllostachys reticulata kock and phyllostachys edulis riv, 2. The formula applied to arrive at correlation coefficient according to correlation table, was $e=\frac{1-{\mu}^2}{\sqrt{\Sigma}X^2y^2}$ the formula for average error was $e=0.6745\frac{1-{\mu}^2}{\sqrt{n}}$ 3. The correlation coefficient and average error by each species were as three tables. 4. Area of the sample plot were 0.5~1 acres. 5. Height, clear-length, circle of breast height, circle of ground height and crown-length of bamboos were measured by weise hypsometer and pole.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.5
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• pp.77-87
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• 2018

Many researches have been focused on localization in WSNs. However, the solutions for localization in static WSN are hard to apply to the mobile WSN. The solutions for mobile WSN localization have the assumption that there are a significant number of anchor nodes in the networks. In the resource limited situation, these solutions are difficult in applying to the static and mobile mixed WSN. Without using the anchor nodes, a localization service cannot be provided in efficient, accurate and reliable way for mixed wireless sensor networks which have a combination of static nodes and mobile nodes. Also, accuracy is an important consideration for localization in the mixed wireless sensor networks. In this paper, we presented a method to satisfy the requests for the accuracy of the localization without anchor nodes in the wireless sensor networks. Hop coordinates measurements are used as an accurate method for anchor free localization. Compared to the other methods with the same data in the same category, this technique has better accuracy than other methods. Also, we applied a minimum spanning tree algorithm to satisfy the requests for the efficiency such as low communication and computational cost of the localization without anchor nodes in WSNs. The Java simulation results show the correction of the suggested approach in a qualitative way and help to understand the performance in different placements.

• Journal of the korean academy of Pediatric Dentistry
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• v.35 no.1
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• pp.118-126
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• 2008

Dental fear is one of the main barriers to the use of dental services, leading patients to avoid periodical dental check-ups or treatments, thus making oral health worse, and sometimes becoming the reason that dental professionals fail control the behavior of patients. Therefore, a dental fear must be controlled carefully in order to promote oral health and effective dental treatment. This study was taken from 313 people 13 to 18 year olds to measure their levels of dental fear. After analyzing the characteristics of dental fear and its related factors, as well as other factors which influence dental fear, we acquired the following results. 1. The level of dental fear was high, compared with advanced countries with relatively good oral health. 2. The strongest physiological response experienced during a dental treatment was the tension of muscles. These dental fears were mainly related to anesthetic needles and drills. 3. Levels of dental fear became higher, the number of times for the dental services utilization had reduced, avoid regular dental examination and perceived oral disease symptoms increased. 4. One of the biggest influences on dental fears turns out to be direct painful experiences and beliefs about dentists.

• Journal of Korea Port Economic Association
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• v.33 no.4
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• pp.59-72
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• 2017

The purpose of this study is to analyze and compare the perceived job satisfaction of logistics company employees and students majoring in logistics who expect to engage in logistics occupations after graduation, and to suggest its implications in improving logistics job satisfaction. Based on previous studies on job satisfaction for logistics and other industries, the pertinent factors to logistics job satisfaction were identified, and a survey was conducted for logistics company employees and students majoring in logistics. Additionally, frequency analysis, reliability analysis, and t-test were performed to compare the differences in logistics job satisfaction. As a result of comparing the perceptions differences in job satisfaction between logistics company employees and students majoring in logistics, each pair of the following were significantly different: personal achievement, social achievement, job prospect, and economic satisfaction. However, there was no meaningful difference in job security and recognition from others.

• Tunnel and Underground Space
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• v.30 no.4
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• pp.306-319
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• 2020

Characterizations of Excavation Damage Zone (EDZ), which is hydro-mechanical degrading the host rock, are the important issues on the geological repository for the spent nuclear fuel. In the DECOVALEX 2019 project, Task G aimed to model the fractured rock numerically, describe the hydro-mechanical behavior of EDZ, and predict the change of the hydraulic factor during the lifetime of the geological repository. Task G prepared two-dimensional fractured rock model to compare the characteristics of each simulation tools in Work Package 1, validated the extended three-dimensional model using the TAS04 in-situ interference tests from Äspö Hard Rock Laboratory in Work Package 2, and applied the thermal and glacial loads to monitor the long-term hydro-mechanical response on the fractured rock in Work Package 3. Each modelling team adopted both Finite Element Method (FEM) and Discrete Element Method (DEM) to simulate the hydro-mechanical behavior of the fracture rock, and added the various approaches to describe the EDZ and fracture geometry which are appropriate to each simulation method. Therefore, this research can introduce a variety of numerical approaches and considerations to model the geological repository for the spent nuclear fuel in the crystalline fractured rock.

• The Journal of Engineering Geology
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• v.17 no.4
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• pp.511-516
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• 2007

Active method MASW(Multi channel Analysis of Surface Waves), which is one of the surface wave exploration methods, has the difficulties to supply enough shear wave velocity log, caused by short spread length and lack of low frequency energy. To make up this defect, the passive method MASW survey is taked and analysised in Daeku subway construction site, Jungpyung-dong Gyeongsan city. The passive method MASW using the microtremor, improve the quality of the overtone record by applying the azimuth correction caused offline sources. And combing with active overtone record which is acquired by same geometry has the benefits of improve shallow depth resolution and extend possible investigation depth. To take the optimized acquisition parameters, the 2m, 4m, and 6m geophone spacing is tested. And 2m spacing overtone image could make the reliable shear wave velocity log.

• Journal of Korean Society of Disaster and Security
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• v.13 no.1
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• pp.25-39
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• 2020

Despite the global promotion of Smart City, there is currently no standard for smart water grid development, and it is not possible to judge the success of Smart City. There is a clear need to establish the requirements and goals of the Smart Water Grid and accurately diagnose and improve the limitations and problems of the existing Smart Water Grid. For this purpose, it is very important to use the index suitable for Smart Water Grid goals. In this study, we developed Smart Water Grid Index which can be used to evaluate the target measurement and attainment of Smart Water Grid and can be utilized based on the implementation plan for Smart Water Grid in the future. Through the development of the Smart Water Grid Key Performance Index (SWG KPI), we will lay the groundwork for continuous capacity evaluation of the Smart Water Grid and improve the reliability of the Index. It is expected that it will be possible to prepare and evaluate a Challenge Evaluation Card for the planned Smart Water Grid by providing an evaluation table for grid competency evaluation.

• Journal of the Korean Society for Railway
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• v.20 no.2
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• pp.203-209
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• 2017

Research on condition monitoring and diagnosis of power facilities has been conducted to improve the safety and reliability of electric power supply. Although insulation diagnostic techniques for unit equipment such as gas-insulated switchgears and transformers have been developed rapidly, studies on monitoring of cables have only included aspects such as whether defects exist and partial discharge (PD) detection; other characteristics and features have not been discussed. Therefore, this paper dealt with PD characteristics against void sizes and positions, and with defect localization in XLPE cable. Four types of defects with different sizes and positions were simulated and PD pulses were detected using a high frequency current transformer (HFCT) with a frequency range of 150kHz~30MHz. The results showed that the apparent charge increased when the defect was adjacent to the conductor; the pulse count in the negative half of the applied voltage was about 20% higher than that in the positive half. In addition, the defect location was calculated by time-domain reflectometry (TDR) method, it was revealed that the defect could be localized with an error of less than1m in a 50m cable.

• Journal of Digital Convergence
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• v.15 no.12
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• pp.517-529
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• 2017

The purpose of this study is to develop and evaluate the scale for university students' health behaviors. This research is based on Roger's(1975) Protection Motivation Theory and Weinstein(1988)'s Precaution Adoption Process Model as theoretical frameworks. The contents of the scale were first abstracted from personal depth interviews of qualitative study on university students' health behavior experiences and review of its related literature. The initial items consisted of 76 behavior questions and 34 perception questions. After conducting the preliminary test, 33 behavior questions and 24 perception questions were selected for the final test by revisions on the basis of the result of the content validity test and the item understanding test. The questionnaires for the final test were distributed to 400 students enrolled in three universities. The questionnaires collected from 373 participants were analyzed by the SPSS program. From the examination of construct validity, item correlation, and factor relation turned out to be relevant. Five factors were determined from 27 items with a cumulative explained variance of 54.498 %. After examining reliability and validity of the collected dat, 27 items were finalized as the scale for university students' health behaviors.