• Journal of the Korean Society for Railway
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• v.13 no.5
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• pp.521-527
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• 2010

The Paved Track is applied to reduce maintenance cost of conventional line. The Paved Track could be used in all types of lines including earthwork, bridge, tunnel and turnout sections. In case of earthwork section, the construction joint is the most critical factor to track durability. The construction joint does not affect to the track structure directly, but the gap due to discontinuity of slabs may affect to the long-term serviceability. To evaluate this problem, the accelerated track test has been performed on the construction joint and the middle part to of the real scale Paved Track. The purpose of this test is that evaluate the vulnerability of construction joint section comparing the trends of settlement and earth pressure under repeated loads of construction joint with those of the middle slab part.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.1760-1767
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• 2007

In Korean railroad-related Organizations facing turbulent environmental change and growth, the introduction of MBO has long been a full-fledged trends. The main reason for this trends is that they need to adapt their system to their vision, mission, value, and strategy in order to gain a sustainable competitive advantage. The purpose of this article is to depict the effectiveness of MBO in railroad-related organizations based on the cognitive response of employees. To attain this purpose, several aspects of current MBO system are surveyed through questionaire and analyzed by SPSS. And some implications will be supposed.

• Korean Journal of Optics and Photonics
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• v.14 no.1
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• pp.38-43
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• 2003

Fabrication process of strain-induced channel waveguides in $LiNbO_3$ was developed using strain-optic effect and compressional strain due to ~1.4 $\mu\textrm{m}$ surface Mo/Pt metal film. Characterization of the channel waveguides revealed a single transverse and depth mode in both TE and TM polarizations. Measurements showed total insertion loss of 6.2 and 7.7 ㏈/cm for TM and TE polarizations. respectively. Electro-optic intensity modulators with 11 mm long electrode length and 21 $\mu\textrm{m}$ electrode gap at $\lambda$ = 1.15 ${\mu}{\textrm}{m}$have been produced in $LiNbO_3$ substrates using strain-induced channel waveguides. Modulation depth of 100% at $\pi$-radian voltage of 16.1V has been demonstrated. Also, 1$\times$2 on/off power splitters at $\lambda$ = 0.63 $\mu\textrm{m}$ have been produced using strain-induced channel waveguides. On/off voltage of $\pm$ 25V has been demonstrated.

• 한국환경농학회:학술대회논문집
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• 2009.07a
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• pp.93-115
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• 2009

There are growing public concerns over crop and food safeties due to the elevated levels of heavy metals grown in contaminated soil. Heavy metals are classified as the chemical harmful risks for crop and food safety. With implementation of GAP, crop safety is controlled by many regulatory options for soil, irrigation water and fertilizers. Any attempt to retard the metal uptake by crops may be the best protocol to secure crop and food safety. This article reviews the management strategies for heavy metals in view of crop safety in Korea and demonstrates results from the field experiments to retard metal translocation from soil to crops by using chemical amendments and soil layer management methods. Major source of soil pollution by heavy metals has been related with mining activities. Risk assessment revealed that rice consumption and groundwater ingestion in the abandoned mining areas were the major exposure pathways for metals to human and the heavy metal showed the toxic effects on human health. Chemical amendments such as lime and slag retarded Cd uptake by rice (Oryza sativa L.) by increasing soil pH, lowering the phytoavailable Cd concentration in soil solution, immobilizing Cd in soil and converting the available Cd fractions into non-available fractions. The soil layer management methods decreased the Cd uptake by 76% and Pb by 60%. Either reversing the surface layer with subsurface layer or immobilization of metals with layer mixing with lime was considered to be the practical option for the in-situ remediation of the contaminated paddy soils. Combination of chemical soil amendments and layer management methods was efficient to retard the metal bioavailability and thus to secure crop safety for heavy metals. This protocol seems to be cheap, relatively easy to practice and practical in the agricultural fields. However, a long term monitoring work should be followed to verify the efficiency of this protocol.

• Archives of Plastic Surgery
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• v.33 no.4
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• pp.454-457
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• 2006

Purpose: The anastomosis of hepatic artery to recipient vessel has a major role in a liver transplantation, so its occlusion is the most important cause of failure of liver transplantations. We made the study to reveal the peculiarities in pediatric liver transplantations compared with adult cases. Methods: From January 1999 to September 2005, we performed 99 cases of pediatric liver transplantation. The mean age at operation was 4.17 years of age. The hepatic vein and portal vein are anastomosed by the general surgeons and then the hepatic artery is anastomosed by the plastic surgeons. The Doppler ultrasonography and computed tomography were used for postoperative checkup for hepatic artery patency. Results: There were no immediate complications, but hepatic arterial occlusion was developed in 3 cases (2.8%). In pediatric patients, the anastomosis of hepatic artery is more difficult than adults because of the rapid respiratory and pulse rate, the small vascular diameter, and the large gap of diameter difference between the recipient and the donor vessels. Conclusion: We could confirm that pediatric liver transplantations are relatively safe but long learning curve was needed.

• Journal of the Korean Society for Precision Engineering
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• v.34 no.1
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• pp.41-46
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• 2017

Magnetically levitated (Maglev) vehicles maintain a constant air gap between guideway and car bogie, and thereby achieves non-contact riding. Since the straightness and the flatness of the guideway directly affect the stability of levitation as well as the ride comfort, it is necessary to monitor the status of the guideway and to alert the train operators to any abnormal conditions. In order to develop a signal processing algorithm that extracts guideway irregularities from sensor data, virtual testing using a simulation model would be convenient for analyzing the exact effects of any input as long as the model describes the actual system accurately. Simulation model can also be used as an estimation model. In this paper, we develop a state-space dynamic model of a maglev vehicle system, running on the guideway that contains jumps. This model contains not only the dynamics of the vehicle, but also the descriptions of the power amplifier, the anti-aliasing filter and the sampling delay. A test rig is built for the validation of the model. The test rig consists of a small-scale maglev vehicle, tracks with artificial jumps, and various sensors measuring displacements, accelerations, and coil currents. The experimental data matches well with those from the simulation model, indicating the validity of the model.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.5
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• pp.199-208
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• 2017

Lithium polymer batteries are used in energy storage systems (ESS), electric vehicles (EVs), etc. due to their high safety, fast charging and long lifecycle, and now they are used in agricultural drones. However, when overcharging and overdischarging, the lithium-polymer battery is destroyed in the gap structure in the lithium-ion battery and the battery life is reduced. In order to prevent overcharge and overdischarge, uneven cell voltage Cell balancing system is needed. In this paper, a fuzzy controller suitable for nonlinear systems is proposed by detecting the unbalanced cells by detecting the voltage difference between charging and discharging of each cell, and suggesting the applied cell balancing algorithm. In this paper, we have designed the cell balancing of the battery pack of agricultural drones by fuzzy control and it is designed for equal control between cells. As a final result, we checked whether cell balancing is good, and when there are two cells, Cell balancing was confirmed. We tested whether it could be used for other products. As a result, we confirmed that cell balancing is good regardless of the number of cells used.

• The Journal of the Korean dental association
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• v.57 no.12
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• pp.736-746
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• 2019

Supportive periodontal therapy(SPT) is essential for the long-term success of periodontal treatment. A patient's compliance with SPT is one of the most important factors affecting periodontal status. There are few studies quantifying compliance with SPT. The aim of this study is to quantify patient's compliance using new method and evaluate tooth loss depending on patient's supportive periodontal treatment compliance index(SPTCI) with SPT. This study included subjects diagnosed with generalized moderate to severe chronic periodontitis, who had completed active periodontal treatment and had SPT over 5 years in Wonkwang university dental hospital. Chart review and radiography analysis were performed. To quantify compliance, SPTCI representing average of gap between recommended schedules and actual visits has been used and evaluated with tooth loss. Mean period of SPT was 8.9 years and mean SPTCI was about 120. In statical analysis, patients who have higher SPTCI with SPT are more likely to have higher rate of tooth loss. Under SPTCI of 120, there were no significant co-relation between SPTCI and tooth loss. Patients diagnosed with moderate chronic periodontitis have significant co-relation between SPTCI and tooth loss, whereas patients diagnosed with severe chronic periodontitis have no co-relation. SPTCI, new method of quantifying compliance in this study, affected to tooth loss. This study suggests that using SPTCI could be helpful for prediction of tooth loss and be used to determine the interval of visit.

• Journal of the Korean Home Economics Association
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• v.42 no.5
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• pp.53-76
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• 2004

This study conducted a survey on sexuality for the purpose of substantial verification, focusing on literature reviews of premarital sexuality. The Literature reviews included relevant studies of our society and its cultures such as premarital sexuality and behaviors, expressions of love or intimacy, contraception, abortion, sex education and sexuality in family contexts. The survey was conducted to 355 university students and 200 working premarital adults in Seoul, Gyeonggi and Gangwon areas. It has 21 questions to measure sexuality by sexual altitude sentence completion Scale (composed of 4 categories and options of the other items)which has been widely used by professional counsel institutes. Male and female students complete the sentence of this scale, then similar contents were classified. Love type test was developed by Hendrick & Hendrick (1986) was used to measure love and intimacy. Results from the sentence completion for sexuality attitudes are generally as follows: First of all, there was clear difference in male md female responses about each categories. For example, With regard to the questions on premarital sex with opposite sex friends of long time relationship, more than half of male students said it is all right, whereas more than half of female students answered to the same questions that it can never be possible, with many answering 'I don't know', or leaving them unanswered. The survey result, masturbation answered that Female is needed however many Females actually don't it. But Male is almost necessary and conduct himself. On questions regarding, Homosexuality is both male and Female answered opposed. These results of the study show that premarital adults clearly open to issues on sexuality compared with the past, but they have not established their own sexual identity, which can be seen with big gap between male and female perspectives, due to experiencing confusion under the changing environment of the society.

• Composites Research
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• v.16 no.2
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• pp.68-73
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• 2003

Interfacial properties and electrical sensing fer fiber fracture in carbon and SiC fibers/epoxy composites were investigated by the electrical resistance measurement and fragmentation test. As fiber-embedded angle increased, the interfacial shear strength (IFSS) of two-type fiber composites decreased, and the elapsed time takes long until the infinity in electrical resistivity. The initial slope of electrical resistivity increased rapidly to the infinity at higher angle, whereas electrical resistivity increased gradually at small angle. Furthermore, both fiber composites with small embedded angle showed a fully-developed stress whitening pattern, whereas both composites with higher embedded angle exhibited a less developed stress whitening pattern. As embedded angle decreased, the gap between the fragments increased and the debonded length was wider for both fiber composites. Electro-micromechanical technique could be a feasible nondestructive evaluation to measure interfacial sensing properties depending on the fiber-embedded angle in conductive fiber reinforced composites.