• Journal of Advanced Navigation Technology
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• v.7 no.1
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• pp.1-5
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• 2003

In this paper, the output power level and phase noise property of nine conventional push-push FET DROs (Dielectric Resonator Oscillator) have been experimentally investigated by adding one more identical DR at the drain port. The nine oscillators designed to generate 20 GHz from 10 GHz fundamental frequency, have been tested for each of three different power combiners at the output port. It has been observed that the output power level of the push-push FET DROs can be improved by placing the DR while maintaining their phase noise characteristics were approximately the same as before adding the DR.

• The Transactions of the Korean Institute of Power Electronics
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• v.24 no.4
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• pp.268-272
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• 2019

A lithium polymer battery-based 9 kJ/s high-voltage capacitor charger, which comprises two stages, is proposed. A modified LCC resonant converter and resonant circuit are introduced at the first and second stages, respectively. In the first stage, the methods for handling low-voltage and high-current batteries are considered. Delta-wye three-phase transformers are used to generate a high output voltage through the difference between the phase and line-to-line voltages. Another method is placing the series resonant capacitor of the LCC resonant components on the transformer secondary side, which conducts considerably low current compared with the transformer primary side. On the basis of the stable operation of the first charging stage, the secondary charging stage generates final output voltage by using the resonance. This additional stage protects the rectifying diodes from the negative voltage when the output capacitor is discharged for a short time. The inductance and capacitance of the resonance components are selected by considering the resonance charging time. The design procedure for each stage with the aforementioned features is suggested, and its performance is verified by not only simulation but also experimental results.

• Archives of Plastic Surgery
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• v.34 no.5
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• pp.622-627
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• 2007

Purpose: Although the autogenous tissue transfer has been the mainstay of the breast reconstruction, concern for the donor site morbidity can lead to the superseded method using tissue expander with implant or permanent expander-implant. However, the additional procedure of tissue expansion possibly cause discomfort and raise the cost. We tried to verify the efficacy of using the saline-filled breast implant by itself for the safe and convenient immediate breast reconstruction modality if the patients have small, round and non-ptotic breasts and the sufficient breast skin can be saved with mastectomy. Methods: From July 2002 to July 2005, 29 breasts of 26 patients were restored only with the saline-filled breast implant immediately after the skin sparing or nipple-areolar skin sparing mastectomy in Asan Medical Center. A pocket with pectoralis major and serratus anterior muscle was created and the implant was covered with this muscle pocket. Simultaneous contralateral augmentation was performed in patients whose mastectomy specimen weighed less than 100g. Results: Using only the saline-filled breast implant resulted in the successful reconstruction with few complications including partial necrosis of nipple areolar skin (five cases, 17.2%), capsular contracture (three cases, 10.3%), hematoma (one case, 3.4%), depigmentation of areolar skin (one case, 3.4%), hypertrophic scar (one case, 3.4%), which were all healed by conservative management. There were no significant complications such as implant exposure and subsequent removal. Conclusion: Immediate breast reconstruction only with the saline-filled breast implant can be a satisfactory alternative option for the patients whose breast is small, round and non-ptotic, especially when the nipple-areolar skin of the breast is preserved in the mastectomy.

• Journal of the Korean Institute of Rural Architecture
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• v.15 no.4
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• pp.35-42
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• 2013

The study aims to investigate general characteristics of Jae-sil from an architectural perspective by grasping location, deployment, structure, and plan composition based on existing inhabited conditions in Jeollabukdo. Results derived from the study are as follows. First, the location of Jae-sil is classified into mountainous and village types, and the two types showed a similar distribution. The village type showed the most distribution in the foot of a mountain in the rear of village, while the mountainous type is close to graveyard. The Jae-sil were mostly exposed to south, southeast, and southeast, which was not significantly different from residence. For deployment of the Jae-sil, a "二" shaped house, where main quarter and gated building are parallel located, can be common, indicating that additional attached building is less required. Second, for the platform out of structural components, coursed masonry was conducted by using natural rocks, and placed were a prop on the platform, first line on processed foot stone, and others on natural foot stone. For pillar, front line round columns, while others square columns. The binding type of the upper part of pillar is dominated by jangyeosujang and sorosujang. For wooden frame structure, 5ryangs were the most distributed, and out of these, 1goju 5ryang was the most generally used. For a roof part, it was composed with gambrel roof with single eave, and the roof was constructed by placing traditional Korean tile roof on the top. Third, for a size of Jae-sil out of plan composition, although the facade and the side of it were presented in a diverse manner, 4 facade rooms and 1.5 side rooms were the most frequently presented, and all Jae-sil were equipped with front ceremonial space. For spatial composition of Jae-sil, main floored hall is placed at the center, and each room is placed on the left and right side to secure space for ancestral rite for participants of it, and for a house with 5 rooms or more, it shows that main floored hall and rooms are weighted from side to side.

• Journal of Korean Library and Information Science Society
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• v.39 no.2
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• pp.493-514
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• 2008

The paper analyzes local children's libraries' status of application of classification scheme and problems and difficulties in its application in order to be used as basic material for development of classification scheme for exclusive use of children's libraries. Through survey, the paper researched 96 local children's libraries, and the results showed that KDC-applied libraries numbered 53 and were the highest, libraries which developed their own classification scheme numbered 22, and libraries which applied classification scheme for children's library numbered 13. Further, many asserted that there needs to be a development of standard classification scheme to be used in children's library. On problems and difficulties in applying classification scheme, notes such as difficulty of accommodating various forms of children's books(such as comic books and picture books), placing too much emphasis on collection of books on certain topic, and lack of topic categories appropriate for characteristics of collected books were voiced, and by holding additional discussion on these, the paper raised the usefulness of the dissertation to be used as basic materials for developing classification scheme for exclusive use of children's library in the future.

• Structural Monitoring and Maintenance
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• v.2 no.3
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• pp.283-300
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• 2015

Visual condition inspections remain paramount to assessing the current deterioration status of a bridge and assigning remediation or maintenance tasks so as to ensure the ongoing serviceability of the structure. However, in recent years, there has been an increasing backlog of maintenance activities. Existing research reveals that this is attributable to the labour-intensive, subjective and disruptive nature of the current bridge inspection method. Current processes ultimately require lane closures, traffic guidance schemes and inspection equipment. This not only increases the whole-of-life costs of the bridge, but also increases the risk to the travelling public as issues affecting the structural integrity may go unaddressed. As a tool for bridge condition inspections, Unmanned Aerial Vehicles (UAVs) or, drones, offer considerable potential, allowing a bridge to be visually assessed without the need for inspectors to walk across the deck or utilise under-bridge inspection units. With current inspection processes placing additional strain on the existing bridge maintenance resources, the technology has the potential to significantly reduce the overall inspection costs and disruption caused to the travelling public. In addition to this, the use of automated aerial image capture enables engineers to better understand a situation through the 3D spatial context offered by UAV systems. However, the use of UAV for bridge inspection involves a number of critical issues to be resolved, including stability and accuracy of control, and safety to people. SLAM (Simultaneous Localisation and Mapping) is a technique that could be used by a UAV to build a map of the bridge underneath, while simultaneously determining its location on the constructed map. While there are considerable economic and risk-related benefits created through introducing entirely new ways of inspecting bridges and visualising information, there also remain hindrances to the wider deployment of UAVs. This study is to provide a context for use of UAVs for conducting visual bridge inspections, in addition to addressing the obstacles that are required to be overcome in order for the technology to be integrated into current practice.

• Steel and Composite Structures
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• v.18 no.2
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• pp.497-517
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• 2015

This study evaluates behavior of the Y-type perfobond rib shear connector proposed by Kim et al. (2013). In addition, an empirical shear resistance formula is developed based on push-out tests. Various types of the proposed Y-type perfobond rib shear connectors are examined to evaluate the effects of design variables such as concrete strength, number of transverse rebars, and thickness of rib. It is verified that higher concrete strength increases shear resistance but decreases ductility. Placing transverse rebars significantly increases both the shear resistance and ductility. As the thickness of the ribs increases, the shear resistance increases but the ductility decreases. The experimental results indicate that a Y-type perfobond rib shear connector has higher shear resistance and ductility than the conventional stud shear connector. The effects of the end bearing resistance, resistance by transverse rebars, concrete dowel resistance by holes, and concrete dowel resistance by Y-shape ribs on the shear resistance are estimated empirically based on the push-out test results and the additional push-out test results by Kim et al. (2013). An empirical shear resistance formula is suggested to estimate the shear resistance of a Y-type perfobond shear connector for design purposes. The newly developed shear resistance formula is in reasonable agreement with the experimental results because the average ratio of measured shear resistance to estimated shear resistance is 1.024.

• The Journal of Korean Academy of Prosthodontics
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• v.59 no.3
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• pp.314-318
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• 2021

There are very few reports of the restoration of tooth loss using dental implants in patients with diffuse sclerosing osteomyelitis (DSO). Because the patients with DSO have unfavorable bone quality for osseointegration of dental implants, additional considerations such as surgical trauma, infection control, and an extended healing period are essential when placing dental implants. The purpose of this study is to report on the success of osseointegration of a dental implant in the patient with DSO.

• Journal of Advanced Navigation Technology
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• v.26 no.2
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• pp.91-98
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• 2022

Unmanned aircraft system traffic management (UTM) service for the safe operation of unmanned aerial vehicles (UAV) such as drones using commercial communication networks such as long-term evolution (LTE) and 5G in low-altitude areas of 150m or less is being studied in several countries. In this paper, whether it is possible to secure three-dimensional (3D) coverage for UTM service using the existing LTE cellular network for terrestrial usersis analyzed through simulations. The practicality in the real environment is confirmed by performing performance analysis in the actual topographical environment and the LTE base station layouts in Korea. According to the analysis results, as the altitude increases, the number of line-of-sight (LOS) interference base stations increases, resulting in a worse signal to interference plus noise ratio (SINR), but coverage is secured except for the limited areas within 150m. was confirmed to be possible. In addition, it is confirmed that a significant proportion of outage areas could be reduced by placing a small number of additional base stations for the outage area.

• Journal of IKEEE
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• v.25 no.4
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• pp.591-597
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• 2021

This paper proposes an EMC-aware PCB design method to reduce electromagnetic emission, where trace length and teturn path of critical signal are shortened by changing chip location and trace layout on the PCB, while additional filters or decoupling capacitors are not required. In the proposed method, signal velocity is calculated for various signals on the PCB. Critical signal with the fastest signal velocity is determined and its return path is shortened as much as possible by placing chip location and trace routing first. Return path of critical signal should be carefully designed not to have discontinuity. Power plane and ground plane should be carefully designed not to be divided, since these planes are the reference of return path. The proposed method was applied to automotive directional Bluetooth speaker which failed to pass CISPR 32 and CISPR 25 EMC tests. Its PCB was redesigned based on the proposed method and it easily passed the EMC tests. The proposed method is useful to EMC-sensitive electronic equipments.