• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.4
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• pp.793-798
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• 2012

In this paper, dependence of subthreshold current has been analyzed for doping distribution and channel structure of double gate(DG) MOSFET. The charge distribution of Gaussian function validated in previous researches has been used to obtain potential distribution in Poisson equation. Since DGMOSFETs have reduced short channel effects with improvement of current controllability by gate voltages, subthreshold characteristics have been enhanced. The control of current in subthreshold region is very important factor related with power consumption for ultra large scaled integration. The deviation of threshold voltage has been qualitatively analyzed using the changes of subthreshold current for gate voltages. Subthreshold current has been influenced by doping distribution and channel dimension. In this study, the influence of channel length and thickness on current has been analyzed according to intensity and distribution of doping.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1048-1053
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• 2005

This paper presents design and integration of the ROBHAZ-DT3, which is a newly developed mobile robot system with chained double-track mechanisms. A passive adaptation mechanism equipped between the front and rear body enables the ROBHAZ-DT3 to have good adaptability to uneven terrains including stairs. The passive adaptation mechanism reduces energy consumption when moving on uneven terrain as well as its simplicity in design and remote control, since no actuator is necessary for adaptation. Based on this novel mobile platform, a rescue version of the ROBHAZ-DT3 with appropriate sensors and a semi-autonomous mapping and localization algorithm is developed to participate in the RoboCup2004 US-Open: Urban Search and Rescue Competition. From the various experiments in the realistic rescue arena, we can verify that the ROBHAZ-DT3 is reliable in traveling rugged terrain and the proposed mapping and localization algorithm are effective in the unstructured environment with uneven ground. The another application is an military robot for an EOD(Explosive Ordnance Disposal) and reconnaissance mission. The military version of the ROBHAZ-DT3 with a water disrupter, a thermal scope and a long distance wireless communication device is developed and sent to the area of military tactics in Iraq. Consequently, the feasibility of the military version of ROBHAZ-DT3 is verified.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.39 no.7
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• pp.7-15
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• 2002

The digital DBS tuner is designed and implemented in a CMOS process using a direct-conversion architecture that offers a high degree of integration. To generate mathched LO I/Q quadrature signals covering the total input frequency range, a fully integrated ring oscillator is employed. And, to decrease a high level of phase noise of the ring oscillator, a frequency synthesizer is designed using a double loop strucure. This paper proposes and verifies a band selective loop for fast frequency switching time of the double loop frequency synthesizer. The down-conversion mixer with source follower input stages is used for low voltage operation. An experiment implementation of the frequency synthesizer and mixer with integrated a 0.25um CMOS process achieves a switching time of 600us when frequency changes from 950 to 2150MHz. And, the experiment results show a quadrature amplitude mismatch of max. 0.06dB and a quadrature phase mismathc of max. >$3.4^{\circ}$.

• Geophysics and Geophysical Exploration
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• v.26 no.1
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• pp.1-7
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• 2023

This study derives the expressions of vector gravity and gravity gradient tensor due to an elliptical cylinder. The vector gravity for an arbitrary three-dimensional (3D) body is obtained by differentiating the gravitational potential, including the triple integral, according to the shape of the body in each axis direction. The vector gravity of the 3D body with axial symmetry is integrated along the axial direction and reduced to a double integral. The complex Green's theorem using complex conjugates subsequently converts the double integral into a one-dimensional (1D) closed-line integral. Finally, the vector gravity due to the elliptical cylinder is derived using 1D numerical integration by parameterizing a boundary of the elliptical cross-section as a closed line. Similarly, the gravity gradient tensor due to the elliptical cylinder is second-order differentiated from the gravitational potential, including the triple integral, and integrated along the vertical axis direction reducing it to a double integral. Consequently, all the components of the gravity gradient tensor due to an elliptical cylinder are derived using complex Green's theorem as used in the case of vector gravity.

• Geophysics and Geophysical Exploration
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• v.27 no.1
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• pp.51-56
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• 2024

In this paper, the vector gravity and gravity gradient tensor of an elliptical disk are derived. The vector gravity of an elliptical disk is defined by differentiating the gravitational potential due to the elliptical disk expressed by a double integral with respect to each axial direction. The vector gravity defined by the double integral is then transformed into a line integral of a closed curve along the elliptical disk boundary using the complex Green's theorem. Finally, vector gravity due to the elliptical disk is derived by 1D parametric numerical integration along the elliptical disk boundary. The xz, yz, zz components of the gravity gradient tensor due to the elliptical disk are obtained by differentiating the vector gravity with respect to vertical direction. The xx, yy, xy components are derived by differentiating the horizontal components of the vector gravity in the form of a double integral with respect to horizontal directions and then using the complex Green's theorem.

• 한국노년학
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• v.38 no.4
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• pp.905-922
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• 2018

The purpose of this study was to examine the mediating effects of generativity and ego-integration on the relationship between leisure activity experience and life satisfaction after retirement, and to clarify the structural relationship between variables. In this study, SPSS for window 21.0 program r and AMOS 18.0 were used. First, correlation analysis was performed among the main variables to investigate the relationship between variables. Next, confirmatory factor analysis and fit of hypothesis model were confirmed. Finally, the bootstrapping procedure was conducted to verify the significance of the indirect effect. The main results of this study are as follows. First, leisure activity experience, life satisfaction, generativity and ego-integration were statistically correlated. Second, in the research model, there was a double-mediated effect of the generativity and ego-integration in the married couple's leisure experience and life satisfaction after retirement. The indirect effect that affects life satisfaction was found to be greater through mediation. This study has limitations in collecting data on retirees who have retirement experience or retired husbands who have. The reason for this is that there is a difference in the sense of life satisfaction between the couple and their spouse, and the significance of the path between the variables may also differ. Therefore, the follow-up study suggests the necessity of analyzing only the couple.

• Journal of Embryo Transfer
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• v.31 no.1
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• pp.1-7
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• 2016

Xenotransplantation involves multiple steps of immune rejection. The present study was designed to produce nuclear transfer embryos, prior to the production of transgenic pigs, using fibroblasts carrying transgenes human complement regulatory protein hCD59 and interleukin-18 binding protein (hIL-18BP) to reduce hyperacute rejection (HAR) and cellular rejection in pig-to-human xenotransplantation. In addition to the hCD59-mediated reduction of HAR, hIL-18BP may prevent cellular rejection by inhibiting the activation of natural killer cells, activated T-cell proliferation, and induction of $IFN-{\gamma}$. Transgene construct including hCD59 and ILI-18BP was introduced into miniature pig fetal fibroblasts. After antibiotic selection of double transgenic fibroblasts, integration of the transgene was screened by PCR, and the transgene expression was confirmed by RT-PCR. Treatment of human serum did not affect the survival of double-transgenic fibroblasts, whereas the treatment significantly reduced the survival of non-transgenic fibroblasts (p<0.01), suggesting alleviation of HAR. Among 337 reconstituted oocytes produced by nuclear transfer using the double transgenic fibroblasts, 28 (15.3%) developed to the blastocyst stage. Analysis of individual embryos indicated that 53.6% (15/28) of embryos contained the transgene. The result of the present study demonstrates the resistance of hCD59 and IL-18BP double-transgenic fibroblasts against HAR, and the usefulness of the transgenic approach may be predicted by RT-PCR and cytolytic assessment prior to actual production of transgenic pigs. Further study on the transfer of these embryos to surrogates may produce transgenic clone miniature pigs expressing hCD59 and hIL-18BP for xenotransplantation.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.71-71
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• 2009

This paper describes a simple, on-chip CMOS compatible the thin-film inductor applied for the dc-dc converters. A fully CMOS-compatible thin-film inductor with a bottom NiFe core is integrated with the DC-DC converter circuit on the same chip. By eliminating ineffective top magnetic layer, very simple process integration was achieved. Fabricated monolithic thin film inductor showed fairly high inductance of 2.2 ${\mu}H$ and Q factor of 11.2 at 5MHz. When the DC-DC converter operated at $V_{in}=3.3V$ and 5MHz frequency, it showed output voltage $V_{out}=8.0V$, and corresponding power efficiency was 85%.

• Proceedings of the IEEK Conference
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• 2002.07a
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• pp.106-109
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• 2002

In the integrated systems, that is integrated digital TV(DTV) internet and home automation, like home server, is needed integration of digital TV video signal and computer graphic signal. The graphic signal is operating at the high speed and has time-divide-stream. So the re-request of data is not easy at the time of error detection. therefore EDAC algorithm is efficient. This paper presents the efficiency error detection auto correction(EDAC) for conversion of graphics signal to DTV video signal. A presented EDAC algorithms use the modified Hamming code for enhancing video quality and reliability. A EDAC algorithm of this paper can detect single error, double error, triple error and more error for preventing from incorrect correction. And it is not necessary an additional memory. In this paper The comparison between digital TV video signal and graphic signal, a EBAC algorithm and a design of conversion graphic signal to DTV signal with EDAC function is described.

• JSTS:Journal of Semiconductor Technology and Science
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• v.4 no.3
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• pp.182-188
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• 2004

We demonstrate a $2.1\;{\times}\;1.0\;{\times}\;0.1cm^3$ sized compact transmitter using LTCC System-in-Package (SiP) technology for 60GHz-band wireless communication applications. For low-attenuation characteristics and resonance suppression of the SiP, we have proposed and demonstrated a coplanar double wire-bond transition and novel CPW-to-stripline transition integrating air-cavities as well as novel air-cavities embedded CPW line. The fabricated transmitter achieves an output of 13dBm at a RF frequency of 62GHz, an IF frequency of 2.4GHz, and a LO frequency of 59.6GHz. The up-conversion gain is 11dB, while the LO signal is suppressed with the image rejection mixer below -21.4dBc, and the image and spurious signals are also suppressed below -31dBc.