• The Journal of Korean Institute of Communications and Information Sciences
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• v.39A no.11
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• pp.637-644
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• 2014

This paper investigates the detection performance of fault location using STDR(sequence time domain reflectometry) and SSTDR(spread spectrum time domain reflectometry) with various length and types of sequences, and then, proposes an improved detection technique by eliminating the injected signal in SSTDR. The detection error rates are compared and analyzed in power line channel model with various fault locations, fault types, and spreading sequences such as m-sequence, binary Barker sequence, and 4-phase Frank sequence. It is shown that the proposed technique is able to improve the detection performance obviously when the reflected signal is weak or the fault location is extremely close.

• Journal of the Korean Society of Visualization
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• v.3 no.1
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• pp.3-19
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• 2005

Novel optical techniques are presented for three-dimensional tracking of nanoparticles; Optical Serial Sectioning Microscopy (OSSM) and Ratiometric Total Internal Reflection Fluorescent Microscopy (R-TIRFM). OSSM measures optically diffracted particle images, the so-called Point Spread Function (PSF), and dotermines the defocusing or line-of-sight location of the imaged particle measured from the focal plane. The line-of-sight Brownian motion detection using the OSSM technique is proposed in lieu of the more cumbersome two-dimensional Brownian motion tracking on the imaging plane as a potentially more effective tool to nonintrusively map the temperature fields for nanoparticle suspension fluids. On the other hand, R-TIRFM is presented to experimentally examine the classic theory on the near-wall hindered Brownian diffusive motion. An evanescent wave field from the total internal reflection of a 488-nm bandwidth of an argon-ion laser is used to provide a thin illumination field of an order of a few hundred nanometers from the wall. The experimental results show good agreement with the lateral hindrance theory, but show discrepancies from the normal hindrance theory. It is conjectured that the discrepancies can be attributed to the additional hindering effects, including electrostatic and electro-osmotic interactions between the negatively charged tracer particles and the glass surface.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.05a
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• pp.241-242
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• 2016

Recently, the interests in safety and prevention from disaster are increasing. In particular, lifeline networks such as water line and sewerage, electricity, gas, and road would be damaged from a disaster. If the lifeline networks do not work in normal, national public service will not properly function. Researches in social network analysis have been conducted for analyzing the interdependency between individuals since 1970s. These network analysis are utilized to investigate a spread of information and disease. However, it is hard to discover the analyzed cases including characteristics of nodes of networks in the area of transportation and disaster. Therefore, this study conducts network analysis of flooded road with flooding scenarios, investigates safe evacuation routes in flooded road network, and suggests efficient approaches for preventing damages from a flooding.

• Journal of Advanced Navigation Technology
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• v.16 no.2
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• pp.401-408
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• 2012

There is a clear need for characterizing optical components with the growing role played by optical devices in measurement, communication, and photonics. A basic and useful measuring parameter to meet this need, especially for imaging systems, is the Modulation Transfer Function, or MTF. Over the past few decades new instrument, including the laser interferometer, the CCD camera, and the computer have revolutionized the measurement and calculation of the MTF. This has made what was tedious and involved into virtually an instantaneous measurement. We proposed a Simpson approxiamtion method to create MTF graph and illustrated real example to verify its method in this paper. This method is very useful while it is very useful because its error is very minor and small although its approximation.

• Journal of Biomedical Engineering Research
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• v.17 no.2
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• pp.165-172
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• 1996

A scanning slot digital mammography system Luing a plastic scintillating fiber screen (SFS) is currently being developed To improve the x-ray interaction efficiency and absorption efficiency of an SFS, high Z elements can be added into the scintillating fiber core. In this paper, we investigated theoretically the zero spatial frequency detective quantum efficiency, DQE(0), and modulation transfer function, MTF(f), of three 2 cm thick SFSs made of polystyrene, polystyrene loaded with 5% by weight of lead, and polystyrene Loaded with 10% by weight of tin scintillating fibers. X-ray interaction efficiency, scintillating light intensity distributions and line spread functions were generated using Monte Carlo simulation. DQE(0) and MTF(f) were computed for x-ray energies ranging from 15 to 50 keV. Loading high Z elements into the SFS markedly increased the DQE(0). For x-ray energies used for mammovaphy, DQE(0) values of both high Z element loaded SFSs are about a factor of three higher than the DQE(0) of an Min-R screen. At mammographic x-ray energies, MTF(f) values of all three SFSs are Venter than 50% at 25 Ip/mm spatial frequency, and were found to be dominated by the 20 um individual scintillating fiber diameter used The results show that both hiP DQE(0) and spatial resolution can be achieved with the high Z element loaded SFSs, which make these SFSs attractive for use in a scanning slot detector for digital mammography.

• Journal of the Korea Society of Computer and Information
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• v.21 no.2
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• pp.43-49
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• 2016

In this paper, we propose the controllability function and service design to efficiently implement the control of the disaster communication network, using Internet of Things(IoT) Technology. In accordance with the spread of Information Communication Technology(ICT), the era for building a disaster communications system without exclusion over the entire areas has emerged. National wireless mesh networks for public safety and disaster relief have been evolving to strengthen the pre-disaster response system using the latest technologies through the convergence of various technologies and services from the viewpoint of the command and control between disaster response agencies. In line with such a technological paradigm shift, the controllability of the objects in the IoT has been emerging as a key quality requirement of a disaster communications system. In this study, the objects are classified by the subject of control according to the IoT component, such as data, network resources and services in order to effectively implement their controllability. In addition, based on the destination of this controllability, technologies and services have been designed that can reduce the damage caused by disasters. Technologies and services that were derived from this study must be implemented in the current disaster safety network systems together with the establishment of an infrastructure for the networks in order that all persons are able to effectively utilize the disaster communications system for their safety.

• The Bulletin of The Korean Astronomical Society
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• v.39 no.1
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• pp.63.2-63.2
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• 2014

As a part of the "Dust, Ice, and Gas In Time" (DIGIT) key program on Herschel, we observed GSS30-IRS1, a Class I protostar located in Ophiuchus (d =125 pc), with Herschel/Photodetector Array Camera and Spectrometer (PACS). More than 70 lines were detected within a wavelength range from 50 ${\mu}m$ to 200 ${\mu}m$: CO lines from J = 14-13 to 41-40, several $H_2O$ lines of Eup = 100 K to 1500 K, 16 transitions of OH rotational lines, and two atomic [O I] lines at 63 and 145 ${\mu}m$. The [C II] line, known as a tracer of externally heated gas by the interstellar radiation field, is also detected at 158 ${\mu}m$. All lines, except [O I] and [C II], are detected only at the central spaxel of $9^{\prime\prime}.4{\times}9^{\prime\prime}.4$. The [O I] emission is extended along a NE-SW orientation, which is consistent with the known outflow direction, while the [C II] line is detected over all spaxels. One possible explanation of the detection of the [C II] line and no correlation of its spatial distribution with any other molecular emission is the existence of the enhanced ISRF nearby GSS30-IRS1. One interesting feature of GSS30-IRS1 is that the continuum emission is extended beyond the point-spread function (PSF), unlike the molecular line emission, indicative of significant external heating. The best-fit continuum model of GSS30-IRS1 with the physical structure including flared disk, envelope, and outflow shows that the internal luminosity is 11 $L_{\odot}$, and the region is also externally heated by a radiation field enhanced by a factor of 25 compared to the local standard interstellar field.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.30 no.3
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• pp.217-222
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• 1985

The yield responses of three isogenic lines in plant type of paddy rice(open-, spread- and broom-type) as affected by combined treatments of transplanting densities (47.62, 22.22, 15.15, 11.11 and 8.33 hills per sq. meter) and rates of fertilizer application (0, 0.5, 1.0 and 1.5 folds of standard rate) were studied by using of the partial differentiations by planting density(D):df(D,F)/dD, fertilizer rate(F):df(D,F)/dF, and their interaction(DXF):d$^2$ f(D,F)/dDdF from the multiple regression polynominal equations. Under the condition of wider planting, the broom-type showed most prominent and sensitive responses in yield among others. Also the action of transplanting density in the broom-type were positive both at lower and higher densities. Under the lower densities, the broom-type represented positive actions both at lower and higher rates of fertilizer application. Whereas the interactions between the density and fertilizer rate under the lower densities were rather negative. To achieve the labor-saving by lower transplanting density(11-14 hills per sq. meter), the amount of fertilizer rates were estimated as 1.3-1.5 folds much of the standard in the open-type, whereas more than 1.5 folds in the broom-type. Thus, the potentials to absorb more amounts of fertilizer may explain the compensating function of the broom-type for equivalent yields of the standards at reduced transplanting densities.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.2
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• pp.155-158
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• 2017

With the help of technical development in the electronic industries, the electronic devices employing the cutting-edged technology are spread in all the area requiring electromagnetic communications. Especially, because of the presence of electronic devices in a variety of research fields like automotive vehicle, train, and aircraft, the research area such as the malfunction and critical damage of the internal system and microwave devices due to the unexpected radiated high-powered EM effects are very important even for the possible occurrence of human damage. In this paper, the effects of electromagnetic fields into the cable connecting the electronic devices and many sensors inside the target structure is treated because of potential malfunction or hardware disorders. In addition, correlation function and transmission line theory have been employed for the analysis of the induced current on the cable inside an electrically large resonant structure.

• Journal of radiological science and technology
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• v.29 no.3
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• pp.133-139
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• 2006

By using CR image pixel data, We examined the way how to calculate the MTF and digital characteristic curve. It can be changed to the text-file(Excel) from a pixel data which was printed with a digital x-ray equipment. In this place, We described the way how to figure out and correct the sharpness of a digital images of the MTF from FUJITA. Excel program was utilized to calculate from radiography of slit. Digital characteristic curve, Line Spread Function, Discrete Fourier Transform, Fast Fourier Transform digital specification curve, were indicated in regular sequence. A big advantage of this method, It can be understood easily and you can get results without costly program and without full knowledge of computer language. It shows many different values by using different correction methods. Therefore we need to be handy with appropriate correction method and we should try many experiments to get a precise MTF figures.