• Proceedings of the KIPE Conference
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• 2016.11a
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• pp.13-14
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• 2016

This paper has introduces a novel Integrated On-board Charger (IOBC) to reduce the size, weight and cost of power conversion stages in Electric Vehicles (EVs). The IOBC is composed of an OBC and a low voltage dc-dc converter (LDC). The IOBC includes a bidirectional ac-dc converter and a bidirectional full-bridge converter with an active clamp circuit. The LDC converter is a hybrid topology combining an active clamped full-bridge converter and a forward converter derived from the Weinburg converter topology. Unlike conventional OBC, the proposed IOBC is compact and the LDC converter of it can achieve a higher efficiency. In addition, the LDC converter of the proposed IOBC can achieve high step-down voltage conversion ratio, no circulating current, no reverse recovery current of the rectifier diodes and small ripple current of output inductor on the auxiliary battery. A 1kW hardware of the LDC converter is implemented to verify the performances of the proposed IOBC.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.139-140
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• 2010

This paper presents an indoor prototype for wireless digital signal transmission using Visible Light Communications (VLC) in which high power Light Emitting Diode (LED) is used. Using low cost and off-the-shelf components, the transmitter module is constructed using an AVR Atmega128 microcontroller and commercial white beam LEDs. Modulating the light intensity of the LED enables digital signals to be transmitted across the optical link. The receiver module employs a high speed PIN photodetector for optical signal detection and a recovery circuit for optical-electro signal conversion. By sending digitalized data via VLC technology, many applications can be realized in the areas of consumer advertising, traffic safety information and disaster control.

• Environmental Engineering Research
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• v.24 no.2
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• pp.347-353
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• 2019

Although membrane distillation (MD) has great promise for desalination of saline water sources, it is crucial to improve its thermal efficiency to reduce the operating cost. Accordingly, this study intended to examine the thermal energy efficiency of MD modules in a pilot scale system. Two different modules of hollow fiber membranes were compared in direct contact MD mode. One of them was made of polypropylene with the effective membrane area of $2.6m^2$ and the other was made of polyvinylidene fluoride with the effective membrane area of $7.6m^2$. The influence of operation parameters, including the temperatures of feed and distillate, feed flow rate, and distillate flow rate on the flux, recovery, and performance ratio (PR), was investigated. Results showed that the two MD membranes showed different flux and PR values even under similar conditions. Moreover, both flow rate and temperature difference between feed and distillate significantly affect the PR values. These results suggest that the operating conditions for MD should be determined by considering the module properties.

• Transactions of the Korean hydrogen and new energy society
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• v.30 no.1
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• pp.58-66
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• 2019

Static compound parabolic collectors (CPCs) have advantages such as ease for fabrication and lower cost compared with other concentrating collectors. In this study, thermal performance analysis of CPC employing heat storage tank was carried out. The clearness index and capacity of heat storage tank are taken as the main parameters for numerical simulation. The effects of the parameters on the hourly and daily system performances ncluding the useful energy, heat loss, and collector efficiency were numerically investigated. Results showed that the system has a potential for efficient recovery of solar thermal energy.

• Journal of Korean Foot and Ankle Society
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• v.23 no.1
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• pp.6-11
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• 2019

As a result of the increased participation in recreational and competitive sports activity, the incidence of chronic lateral instability has risen. Because chronic ankle instability can cause significant comorbidity and increase the social cost, the interest in this issue is growing. Although there are well-documented and effective surgical treatments for managing this condition, conservative treatments are a viable first option in selected patients. Through conservative treatment, surgical treatments can be reduced or delayed without necessarily affecting the overall outcome, but the failure of conservative treatment results in the need for surgical treatment to reduce the long term complications. Appropriate postoperative rehabilitation is essential for adequate functional recovery, even when surgical treatment is required.

• Genomics & Informatics
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• v.16 no.4
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• pp.30.1-30.6
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• 2018

There is urgent need for effective and cost-efficient data storage, as the worldwide requirement for data storage is rapidly growing. DNA has introduced a new tool for storing digital information. Recent studies have successfully stored digital information, such as text and gif animation. Previous studies tackled technical hurdles due to errors from DNA synthesis and sequencing. Studies also have focused on a strategy that makes use of 100-150-bp read sizes in both synthesis and sequencing. In this paper, we a suggest novel data encoding/decoding scheme that makes use of long-read DNA (~1,000 bp). This enables accurate recovery of stored digital information with a smaller number of reads than the previous approach. Also, this approach reduces sequencing time.

• Food Science and Industry
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• v.51 no.2
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• pp.100-113
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• 2018

To obtain an edible grade oil from crude oil extracted from oil-bearing materials, it is generally necessary to carry out a refining process composed with degumming, deacidification, bleaching, and deodorization, to remove undesirable matters which affect the quality and shelf life of oils. The main purpose of degumming is to remove gum material mainly consisted with phospholipids. Phospholipases convert nonhydratable phospholipids into their hydratable forms which can be removed by centrifugation. In comparison with conventional water and acid degumming processes, enzymatic degumming can result the lower phosphatide content in oil than conventional processes. The enzymatic degumming can be conducted with the reduced amount of acid, and contributes to generate less amount of wastewater, decrease of operating cost, and increase oil recovery yield. The phospholipases used in enzymatic degumming process are phospholipase A1, A2, B, and C.

• International Journal of Internet, Broadcasting and Communication
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• v.14 no.3
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• pp.161-170
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• 2022

Recently, NAND-type flash memory has been regarded to be new promising storage media for large-scale database systems. For flash memory to be employed for that purpose, we need to reduce its expensive update cost caused by the inablity of in-place updates. To remedy such a drawback in flash memory, we propose a new flash-aware buffering scheme that enables virtual flushing of dirty pages. To this end, we slightly alter the tradional algorithms used for the logging scheme and buffer management scheme. By using the mechanism of virtual flushing, our proposed buffering scheme can efficiently prevent the frequenct occureces of page updates in flash storage. Besides the advantage of reduced page updates, the proposed viurtual flushing mechanism works favorably for shorneing a recocery time in the presense of failure. This is because it can reduce the time for redo actions during a recovry process. Owing to those two benefits, we can say that our scheme couble be very profitable when it is incorporated into cutting-edge flash-based database systems.

• Membrane and Water Treatment
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• v.14 no.4
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• pp.175-180
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• 2023

Mixed matrix membranes (MMMs) can be a promising alternative for the solution of dye removal from coloured effluents. Polymeric membranes are widely used due to their good film-forming ability, flexibility, separation properties, and cost. However, they have low mechanical, chemical, and thermal resistances. Moreover, the fouling of polymeric membranes is high because of their hydrophobic nature. Hence, there is an increasing interest in organic-inorganic hybrid membranes as a new-generation membrane material. It has been shown that carbon nanotubes have the potential to increase the material properties of polymers with their low density, high strength, hardness, and exceptional aspect ratio. In this work, carbon nanotubes blended MMMs were prepared and methyl orange removal efficiency of them was investigated. Compared to the bare membranes, MMMs showed not only increased hydrophilicity, water content, and pure water flux but also increased methyl orange rejection and flux recovery

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.8A
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• pp.1085-1095
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• 2000

In this paper, we have defined the rules and the algorithm for diagnosis and recovery of routing configuration fault on a system. By using them, we have implemented the Java-based system that can manage routing configuration fault automatically. To manage routing configuration fault, the production rule for network configuration management, the production rule for routing configuration fault diagnosis, and the production rule for routing configuration fault recovery have been proposed. Rule-based routing configuration fault management system has been implemented on the basis of backward chaining algorithm and applied for meta rules for the purpose of interconnecting the production rules. We have derived the experimental result from transition process of the rules, the Blackboard, the goals based on scenarios. Through the implementation of dynamically applicable system in heterogeneous and rapidly changing network environments, we have proposed the methodology for network configuration fault management. Also, we expect that network configuration manager can reduce time and cost wasted for routing configuration fault management.