• Journal of Korean Neurosurgical Society
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• v.54 no.6
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• pp.461-466
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• 2013

Objective : Although curcumin has a protective effect on bone remodeling, appropriate therapeutic concentrations of curcumin are not well known as therapeutic drugs for osteoporosis. The purpose of this study was to compare the bone sparing effect of treatment of low-dose and high-dose curcumin after ovariectomy in rats. Methods : Forty female Sprague-Dawley rats underwent either a sham operation (the sham group) or bilateral ovariectomy (OVX). The ovariectomized animals were randomly distributed among three groups; untreated OVX group, low-dose (10 mg/kg) curcumin administered group, and high-dose (50 mg/kg) curcumin group. At 4 and 8 weeks after surgery, serum biochemical markers of bone turnover were analyzed. Bone histomorphometric parameters of the 4th lumbar vertebrae were determined by micro-computed tomography (CT). In addition, mechanical strength was determined by a three-point bending test. Results : High-dose curcumin group showed significantly lower osteocalcin, alkaline phosphatase, and the telopeptide fragment of type I collagen C-terminus concentration at 4 and 8 weeks compared with the untreated OVX group as well as low-dose curcumin group. In the analyses of micro-CT scans of 4th lumbar vertebrae, the high-dose curcumin treated group showed a significant increase in bone mineral densities (p=0.028) and cortical bone mineral densities (p=0.036) compared with the low-dose curcumin treated group. Only high-dose curcumin treated group had a significant increase of mechanical strength compared with the untreated OVX group (p=0.015). Conclusion : The present study results demonstrat that a high-dose curcumin has therapeutic advantages over a low-dose curcumin of an antiresorptive effect on bone remodeling and improving bone mechanical strength.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.2
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• pp.548-553
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• 2013

EHPS(Electro-Hydraulic Power Steering) is a system to generate the steering operation force from the electric motor connected directly to the oil pump. To optimize the manufacturing cost and efficiency of the performance of the steering system is very important. Until now, the development of the hydraulic system is implemented by the field test which needs a significant time and cost. In this paper, flow measurement of an external gear pump is performed. Then using the experimental results, an approximate model expressed by flow rate characteristics is proposed to calculate the discharge flow rate. Proposed approximate model is verified by comparing with the experimental data and AMESim results. As the experimental data and AMESim results agree well, the approximate model data can be used as an alternative to highly cost experimental procedure.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.2
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• pp.573-577
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• 2013

Heat pumps come into wide use because high energy efficiency can be obtained and diverse heat sources like geothermal heat, waste heat and air are available. It is necessary for an air source heat pump to defrost in order to remove frost on the surfaces of an outdoor heat exchanger. It is impossible for continuous heating if reverse cycle operation is used as defrosting method, furthermore it causes the degradation of COP. In this study an fin-tube heat exchanger with three rows was used as an outdoor coil. One row among three rows of the heat exchanger was used like a condenser in order to remove frost on it, the others were used as evaporator to accomplish continuous heating. Each row was switched in order from a condenser to an evaporator in specified time interval. Tests were carried out during minimum 180 minutes at the defrost-heating test condition(dry bulb temperature $2^{\circ}C$, wet bulb temperature $1^{\circ}C$) described in KS C 9306. Time-averaged COP was about 20% higher than that of conventional defrosting method.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.11
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• pp.349-356
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• 2020

The heat release rate (HRR) and fire growth rate of fire for the solid combustibles consisting of multi-materials was measured through the ISO 9705 room corner test, and the computational analysis in a closed compartment was performed to simulate a fire using the heat release rate prediction model provided by a Fire Dynamics Simulator (FDS). The method of predicting the heat release rate provided by the FDS was divided into a simple model and a pyrolysis model. Each model was applied and computational analysis was performed under the same conditions. As the solid combustible consisting of multi-materials, a cinema chair composed mostly of PU foam, PP, and steel was selected. The simple model was over-predicted compared to the predicted heat release rate and fire growth rate using the pyrolysis model in a closed compartment.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.2
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• pp.69-76
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• 2010

Recently, the natural environment changes drastically and the frequency of occurrence for lightning has gradually been increased. Such lightning delivers high volume of energy along the power line and communication line to the equipment in use. The high volume of energy arising from the lightning surge develops in fast velocity to destroy the facilities in power source and many other facilities in operation in sequential destruction with vast energy. This paper examines the characteristics of ZnO varistor to prevent from thermal runaway. We carry out performance evaluation of electrical characteristics on ZnO varistor. we will develop ZnO varistor Prevented from thermal explosion using test result of this paper.

• Journal of the Korean Society of Safety
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• v.32 no.6
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• pp.54-60
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• 2017

A railway rail will be corroded by the repetitive sea wind and fog in the splash and tidal zone such as Youngjong grand bridge. And these rusts of rail could be increased by increasing service period, and it frequently occurred the safety accidents or disorders in electrical problem. In this study, the sacrificial anode cathodic protection method was proposed as a measures for reducing the corrosion of the railway rails in the oceanic climate conditions. As the results of immersion test using the salt water during four months, the sacrificial anode cathodic protection method using the aluminum anode(Al-anode) was evaluated that a distinct effect on corrosion reduction in the rails. Therefore the sacrificial anode cathodic protection method was experimentally proven that a disorders in aspects electric and signal of railway operation condition such as direct fixation track system in Youngjong grand bridge could be prevented by reducing rust falling from the rail. In addition, the installation conditions of the anodes directly affect the transmission range of corrosion potential, the sectional loss of anode, and the corrosion reduction effect. Therefore, to expect the corrosion reduction effect of rails under the oceanic climate conditions for railway track, it was important to adopted the appropriate spacing of anode installation by considering the actual field conditions.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.8
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• pp.1654-1660
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• 2004

In this paper, we describes the design and implementation of LonWorks communication module for distributed intelligent control using LonWorks technology of Echelon. LonWorks communication module can be divided hardware and firmware. First, hardwares is divided into microcontroller attaching sensors and LonWorks components for working together control network and data network. Hardwares are consisted of neuron chip, microcontroller, transceiver, LONCard. Second, operating firmware is realized with neuron C using NodeBulider 3.0 development tool. Produced and implemented LonWorks communication module is pretested using LTM-10A, Gizmo 4 I/O board, parallel I/O Interface. For field test, microcontroller module part is tested by HyperTerminal, communication procedure in data network is certified by transmitting and receiving short message using LonMaker for Windows tool. Herewith, LON technology is based on network communication technique using LonWorks.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.4
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• pp.835-842
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• 2012

Operating Systems is a discipline which handles abstract concepts and techniques. However, most of OS courses have been textbook-oriented theoretical classes. Theoretical classes lead to the decline in the understanding of a lecture, and hurt their concentration. Many instructors have tried to make use of educational tools to help students understand lectures and arouse interests. This paper describes the design and implementation of a CPU scheduling simulator which shows the operation of process scheduling algorithms visually. The academic achievement evaluation for 2010's students and 2011's and t-test results show that the differences of the correct answer ratio for the exam about CPU scheduling algorithms are meaningful. The survey shows that the simulator is useful as an educational tool which causes the interests and enhances the understanding of a lecture, this teaching method is effective to develop problem solving skills.

• Journal of Practical Engineering Education
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• v.7 no.1
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• pp.47-55
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• 2015

This study has the objective of proposing the basic data for the political and administrative support needs so that the Echo generation can be prepared with the supper-aged society, by verifying the perception level and degree of necessity about the outplacement support service, whether they want to be serviced or not, and necessary contents in the service with the employed people and non-employed people as objects among the Echo generation in the Southeast region. The study result derived from these effort is illustrated as follows. The perception level of the Echo generation about outplacement support service showed to be significantly different according to the gender, age, industry type, and career. The degree of needs was significantly different depending on the age. For the provision period of the outplacement support service, the opinions were that 3 months before the retirement was most appropriate. The intention of participation when the outplacement support service is provided showed to be significantly different depending on the age.

• The Journal of Society for e-Business Studies
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• v.16 no.3
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• pp.263-274
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• 2011

The KEC XML Electronic Tax Invoice v3.0 which is a typical example of XML document was developed in 2009 according to the amendment of the Value Added Tax Law in 2008 that obliged all the corporation business to issue tax invoices electronically and submit them to the National Tax Service. The issue and submission of those tax invoices has been implemented since Jan. 2011 through a pilot test in 2010. It has some differences in aspect of standard, developing subject, technologies, and operation with the previous version of it. Above all, it is the first case of the XML document being developed based on international standard and methodologies and distributed nationally. This study aims to guide the future development of same kinds of standard XML document by arranging the development and distribution processes of XML Tax Invoice comprehensively.