• Proceedings of the Korean Geotechical Society Conference
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• 2005.10a
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• pp.389-394
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• 2005

In this study we carried out to evaluate the salinity concentration and volumetric water content of unsaturated soil column using frequency domain Reflectometry with vector network analyzer (FDR-V) measurement system. All of experiments were considered to the effect of temperature which ranges from l0$^{\circ}C$ to 50$^{\circ}C$ increasing the interval of l0$^{\circ}C$ controlled by the constant temperature container. From the results the responses of complex dielectric constant which consist of the real part and imaginary parts have the effect of volumetric water content and concentration of salinity at 1GHz. Use of derived equations (1) and (2) can be calculated the physical parameters such as volumetric water content and salinity concentration of unsaturated media by the responses of complex dielectric constant.

• Journal of Korea Multimedia Society
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• v.3 no.5
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• pp.470-478
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• 2000

Color images from various application areas have their own characteristics. Practical segmentation systems need specialized methods to death with the characteristics. In this paper. we propose a distributed genetic algorithm based segmentation method for color breast carcinoma cell images. To extract positive nuclei and negative nuclei from the cell images, a distributed genetic algorithm with improved genetic operations and an evaluation function is used. As initial values, representative colors from images are introduced to work well with the cell images. A test to verify the validity of the proposed method shows well-segmented images. This result suggests that the method is pertinent to be but into practical use for the images haying limited objects with limited colors.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.5
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• pp.913-921
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• 2009

This paper suggests a deign method of the model-following $H{\infty}$ control system having robust performance. This $H{\infty}$ control system is designed by applying genetic algorithm(GA) with reference model to the optimal determination of weighting functions and design parameter ${\gamma}$ that are given by $H{\infty}$ control theory. These weighting functions and design parameter ${\gamma}$ are optimized simultaneously in the search domain guaranteeing the robust performance of closed-loop system. The effectiveness of this $H_{\infty}$ control system is verified by computer simulation.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.39 no.4
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• pp.1-9
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• 2002

The distribution characteristics of data retention time for DRAM was studied in connection with the probability distribution of the cell parameters. Using the cell parameters and the transient characteristics of cell node voltage, data retention time was investigated. The activation energy for dielectric layer growth on cell capacitance, the recombination trap energy for leakage current in the junction depletion region, and the sensitivity characteristics of sense amplifier were used as the random variables to perform the Monte Carlo simulation, and the probability distributions of cell parameters and distribution characteristics of cumulative failure bit on data retention time in DRAM cells were calculated. we found that the sensitivity characteristics of sense amplifier strongly affected on the tail bit distribution of data retention time.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.8 no.5
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• pp.51-56
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• 2008

In this paper, we propose a printed planar antenna suitable for mobile wireless communications. Since the printed antenna is easy to fabricate due to simplicity, low cost, and light weight, it is widely used in communications systems. The conventional patch antenna takes too much surface area to be applied to a mobile receiver. Although the size is reduced using the printed antenna, still reasonably wide bandwidth should be considered. To overcome the disadvantage of narrow bandwidth, the substrate should be physically thick and the dielectric constant should be small. In this work, we suggest a simple form of printed planar antenna and show the optimal input impedance depending on the antenna size and operating frequency. The performance evaluation is achieved analytically for a prototype antenna model.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.5
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• pp.795-801
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• 2001

A method of miniaturizing branch line coupler is presented. The method utilizes the microstrip line with overlay(or superstrate). The frequency dependent characteristics, dispersion and characteristic impedance, of this line are obtained by Immitance method in spectral domain and Method of Line. The relevant spectral domain Green's function is given and used to obtain numerical results. The branch line couplers with overlays are designed and fabricated at 2 GHz. The experimental results show that the size of coupler with overlay(${epsilon}_r$=10.2) is 31.4 precent smaller than conventional coupler. This minimized coupler is suitable for Butler Matrix as feeder for mobile communication beam forming antenna.

• The Korean Journal of Applied Statistics
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• v.16 no.2
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• pp.195-202
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• 2003

Haplotype analysis in SNP is very useful for the study of complex genetic disease due to low cost and high efficiency comparing to individual analysis of each SNP, and is functionally important in biological view. But, the gametic phase of haplotypes is usually unknown in SNP group, and it is difficult to predict haplotype proportions. In this study, haplotype proportions were estimated using EM algorithm from diploid data of SNP group in solid tumor group and normal group. From these results, linkage disequilibrium among SNPs was analyzed.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.188-188
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• 2011

MgO는 암염구조의 이온결합성 화합물로 7.8 eV의 높은 띠 틈과 약 95%의 탁월한 투과도를 갖는다. 또한, ${\gamma}$ process에 의한 이차 전자 방출이 높고 이온 스퍼터링에 의한 표면 손상이 적어 면 방전 AC-PDP의 보호막으로 이용된다. 따라서 MgO 보호막에 관한 연구는 이차 전자 방출 계수를 높여 방전 전압을 감소시키고 높은 유전율과 투과도를 유지시키기 위한 목적으로 전개되어지고 있다. 본 연구는 이온 스퍼터링에 의한 MgO 보호막의 표면 특성의 변화를 알아보기 위해 이루어졌다. MgO 박막은 electron beam evaporation의 방법을 통해 챔버 내에 O 기체를 주입하고 P type Si 기판을 300$^{\circ}C$ 가열하여 40 nm 두께로 제작되었다. 박막 시료는 표면분석 전 초고진공챔버 내에서 표면에 산화된 불순물 제거를 위해 550$^{\circ}C$의 열처리가 되어졌다. 그리고 250 eV의 He 이온으로 박막 표면을 스퍼터링 하여 XPS, REELS, UPS를 이용하여 전자 및 광학적 특성을 연구하였다. XPS 분석을 통해 MgO 박막은 He 이온 스퍼터링에 의해 표면의 화학적 조성이 변하지 않는다는 것을 확인했다. MgO 박막에 이온 스퍼터링을 하면 표준 시료와 비교하여 Ep=1,500 eV일 때 7.54 eV에서 7.63 eV로 높아지는 경향이 있다. 일함수는 He 이온 스퍼터링 한 결과 3.85 eV로부터 4.09 eV로 약간 높아졌다. 또한, QUEELS simulation으로 얻은 가시광 투과도는 91~92%로 분석되었다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.7
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• pp.1770-1776
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• 1998

This paper presents a waveguide-to-mircostrip transition at Ka-band using antipodal finlines. Critical design parameters were identified with the help of theoretical analysis. Experimental optimization was performed together with 3-D FEM analysis in an effort to find optimum dimensions of the transition. In addition to the conventional antipodal finline transition, a new dielectric impedance transformer was introduced to further reduce the insertion loss. Optimized waveguide-to-microstrip transition showed an insertion loss of 0.3~0.4dB/transition at Ka-band. This transition provides superior reproducibility and better performance than conventional coaxcable-to-microstrip transition.

• The Journal of the Korea institute of electronic communication sciences
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• v.6 no.5
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• pp.649-656
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• 2011

This study is a numerical representative modelling analysis for applying the process that unravels networks between cells in genetics to Network of informatics. Using the probabilistic graphical model, the insight from the data describing biological networks is used for making a probabilistic function. Rather than a complex network of cells, we reconstruct a simple lower-stage model and show a genetic representation level from the genetic based network logic. We made probabilistic graphical models from genetic data and extend them to genetic representation data in the method of network modelling in informatics.