• Journal of the Society of Naval Architects of Korea
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• v.28 no.1
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• pp.12-18
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• 1991

Three-dimensional nonlinear sloshing effects due to tank motions are simulated by solving boundary value problem using the panel method based on boundary integral technique. While Shinkai used boundary elements on which source strengths vary linearly between nodes, the source of constant strength is distributed on each triangular panel in the present study. The source strength at each time step is determined by solving the Fredholm integral equation of the second kind obtained from Green's theorem. To avoid cumulative numerical errors as time elapses, Adam-Bashforth-Moulton method is employed. Numerical examples for the case of partially filled spherical tank on board oscillating in harmonic sway mode or pitch mode are solved. The elevation of the free surface is compared with the result by Shinkai and confirmed in good agreement during early time. The input and the output energy are comparatively evaluated to check the overall accuracy of the present numerical scheme. Although some leakage of energy are found as time marches, it is plausible when we take into account nonlinearities of the problem and the number of panels of the model.

• The Transactions of the Korean Institute of Power Electronics
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• v.10 no.6
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• pp.578-586
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• 2005

Recently, due to the launch of digital broadcasting service, the demand of Flat Panel Display (FPD) is sharply rising. Among them, the PDP is expected to be one of the most promising digital displays of next generation because of its large screen size, high resolution, thinness and board field of view. Meanwhile, the PDP uses ADS (Address Display-period Separation) scheme which divide one subfield into address and sustaining period to express the grey scale of images. Since the output of sustaining power module Is mostly used for sustaining period, the load of the sustaining power module can be considered as a pulsating load. Due to this particular load condition, if the wide ZVS range of the power switches is not guaranteed, the hard switching causes large amount of switching loss and serious thermal problem in power module. In this paper, a high efficiency power conversion circuit for 60' PDP sustaining power module which achieves wide ZVS range with the help of additional ZVS tank is proposed. According to the various gating methods, the different operations of the proposed converter are presented. And, to confirm the properties of the proposed converter, an experimental prototype of 900W power converter is constructed md tested. As a result, more than $92\%$ of high efficiency is obtained at $10\%$ load condition, and the ZVS operation is achieved from full load to $10\%$ load condition.

• Journal of the Korean Wood Science and Technology
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• v.42 no.3
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• pp.309-317
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• 2014

Harvested wood products (HWP) are known as products from the tree such as sawn wood, plywood, particle board, structural lumber, wooden interior material, wooden furniture, and paper products. Because carbon is locked up in the HWP until eventual end-use of HWP, HWP played a role as the carbon storage which has the effect of stabilizing the concentration of carbon dioxide in the atmosphere. For these reasons, the suggestion that it must admit the carbon storage effect of HWP has been constantly raised. In 2011, the 17th session of the Conference of the Parties (COP) to the United Nations Framework Convention on Climate Change (UNFCCC) which was held in Durban, South Africa, assigned "Production Approach" which targets only the HWP producted by using round wood of domestic forestry as a official method for carbon accounting. Therefore, it is necessary that each country has to determine the half-life of wood in order to correspond to the discussions and negotiations between countries in the future and to develop an inventory of product-specific domestic wood. In this study, some countries' examples of the methods and conditions for determining half-life of HWP were investigated, and it was tried to derive the factor and methodology to determine half-life span of domestic HWP appropriately.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.369-372
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• 2002

In this research, a vision system for detecting tool breakage which is hardly detected by such indirect in-process measurement method as acoustic emission, cutting torque and motor current was developed and embedded into a PC-NC system. The vision system consists of CMOS image sensors, a slit beam laser generator and an image grabber board. Slit beam laser was emitted on the tool surface to separate the tool geometry well from the various obstacles surrounding the tool. An image of tool is captured through two steps of signal processing, that is, median filtering and thresholding and then the tool is estimated normal or broken by use of change of the centroid of the captured image. An air curtain made by the jetting high-pressure air in front of the lens was devised to prevent the vision system from being contaminated by scattered coolant, cutting chips in cutting process. To embed the vision system to a Siemens PC-NC controller 840D NC, an HMI(Human Machine Interface) program was developed under the Windows 95 operating system of MMC103. The developed HMI is placed in a sub window of the main window of 840D and this program can be activated or deactivated either by a soft key on the operating panel or M codes in the NC part program. As the tool breakage is detected, the HMI program emit a command for automatic tool change or send alarm to the NC kernel. Evaluation test in a high speed tapping center showed the developed system was successful in detection of the small-radius tool breakage.

• Journal of the Korean Wood Science and Technology
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• v.34 no.3
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• pp.30-37
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• 2006

The present study examined the formaldehyde (HCOH) emission characteristic of various wood-based panel used in interior design, and measured changes in formaldehyde emission when a number of VOC reduction methods were applied. Formaldehyde emission showed a clear tendency of increase with the rise of temperature, and the concentration of formaldehyde emitted changed according to the preprocessing condition before measuring. Formaldehyde emission from wood board after bake out treatment was lower than that of the control group. When specimens were coated with urethane, cashew, water, oil stain, they generally showed the decrease of formaldehyde emission, although varying according to finishing material, and when edge sealing was applied the decrease became significant. $TiO_2$ coating was more effective in decreasing formaldehyde under ultraviolet lamps than under ordinary lamps. When the irradiation of ultraviolet lamps gets longer, formaldehyde emission decreased.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.4
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• pp.940-947
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• 2015

This paper presents the region of interest pattern image extraction method on a display printed matrix pattern. Proposed method can not use conventional method such as laser, ultrasonic waves and touch sensor. It searches feature point and rotation angle using luminance and pattern reliable feature points of input image, and then it extracts region of interest. In order to extract region of interest, we simulate proposed method using pattern image written various angles on display panel. The proposed method makes progress using the OpenCV and the window program, and was designed using Verilog-HDL and was verified through the FPGA Board(xc6vlx760) of Xilinx.

• International Journal of Automotive Technology
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• v.7 no.5
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• pp.571-577
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• 2006

This paper deals with dynamic tensile characteristics for the polypropylene used in an IP(Instrument Panel). The polypropylene is adopted in the dash board of a car, especially PAB(Passenger Air Bag) module. Its dynamic tensile characteristics are important because the PAB module undergoes high speed deformation during the airbag expansion. Since the operating temperature of a car varies from $-40^{\circ}C$ to $90^{\circ}C$ according to the specification, the dynamic tensile tests are performed at a low temperature($-30^{\circ}C$), the room temperature($21^{\circ}C$) and a high temperature($85^{\circ}C$). The tensile tests are carried out at strain rates of six intervals ranged from 0.001/sec to 100/sec in order to obtain the strain rate sensitivity. The flow stress decreases at the high temperature while the strain rate sensitivity increases. Tensile tests of polymers are rather tricky since polymer does not elongate uniformly right after the onset of yielding unlike the conventional steel. A new method is suggested to obtain the stress-strain curve accurately. A true stress-strain curve was estimated from modification of the nominal stress-strain curves obtained from the experiment. The modification was carried out with the help of an optimization scheme accompanied with finite element analysis of the tensile test with a special specimen. The optimization method provided excellent true stress-strain curves by enforcing the load response coincident with the experimental result. The material properties obtained from this paper will be useful to simulate the airbag expansion at the normal and harsh operating conditions.

• Nutrition Research and Practice
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• v.1 no.2
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• pp.89-93
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• 2007

Many countries such as The Republic of Korea have established their own nutritional standards, collectively termed Nutrient Reference Values (NRVs), and they vary due to the science which was reviewed, the purposes for which they are developed, and issues related to nutrition and food policy in the country. The current effort by the Codex Alimentarius Committee on Nutrition and Foods for Special Dietary Uses (CNFSDU) to update the NRVs that were established following the Helsinki Consultation in 1988 represents an opportunity to develop a set of reference values reflecting current scientific information to be used or adapted by many countries. This paper will focus on possible approaches to selecting or developing reference values which would serve the intended purpose for nutrition labeling to the greatest extent possible. Within the United States, the Food and Drug Administration (U.S. FDA) is currently reviewing regulations on nutrition labeling to better address current health issues, and is expected to enter into a process in the next few months to begin to explore how best to update nutrient Daily Values (DVs), most of which are still based on the Recommended Dietary Allowances (RDAs) of the Food and Nutrition Board, U.S. National Academy of Sciences, last reviewed and revised in 1968. In this presentation, I review the current purposes in the U.S. for nutrition labeling as identified in the 1938 Food, Drug, and Cosmetic Act as amended, the scientific basis for current nutrition labeling regulations in the United States, and the recommendations made by the recent Committee on Use of Dietary Reference Intakes in Nutrition Labeling of the Institute of Medicine (2003) regarding how to use the DRIs in developing new DVs to be used on the label in the United States and Canada. Based on these reviews, I then provide examples of the issues that arise in comparing one approach to another. Much of the discussion focuses on the appropriate role of nutrient labeling within the Nutrition Facts panel, one of the three major public nutrition education tools in the United States (along with MyPyramid and Dietary Guidelines for Americans).

• Journal of Korean Academy of Nursing Administration
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• v.15 no.4
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• pp.527-538
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• 2009

Purpose: The purpose of this study was to reclassify the advanced nursing practices of critical care nurse practitioners(CCNPs) in intensive care unit and measure the time and frequency of CCNP's activities. Method: Practices of ICU nurses are divided into RN's and CCNP's practices by a panel of ICU nursing experts. Each practice of CCNP is defined and CCNP's working time and service frequencies are monitored in general hospitals. Result: Practices of CCNP were classified into 4 domains and 32 practices. Fourteen practices by CCNPs were completed in 10 minutes and the other 12 practices consumed 10-30 minutes. A priority of practice in respiratory therapy was given to artificial airway management, management of tracheostomy patient, lower respiratory care, and the priority of CRRT was management of anticoagulation. Conclusions: Advanced nursing practices of CCNPs were recognized from those of RNs. A further research of CCNPs practices should be extended to other advanced practices and it is required to evaluate economic value of advanced nursing practice in the national health insurance system.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.1
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• pp.101-108
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• 2005

When a heavy rain occurs, many electrical shock victims are produced every year because lamp poles are under water. In order to prevent electrical shock accidents at a street lamp, the investigation was carried out at real field conditions. The investigation was performed about the circuit configuration of a panel board, a wiring method, a grounding conductor, a lamp pole and so on. The related regulation was analyzed and the problems were presented. Also, the domestic and foreign things were compared and analyzed by the investigation of the field conditions, and the related standard was already revised. Through investigating the field conditions and analyzing the related regulation, it is intended to present the real data to establish more effective preventive measures against electrical shock accidents at a street lamp to be installed on the road. In the future, the analytical data can be applied to stabilize other electrical facilities on the road as well as a street lamp, and to reduce the electrical disasters.