• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.05a
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• pp.861-863
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• 2014

Fingerprinting technique exists at the position assumption system for the service of indoor location-based. However, there is a problem it takes a long time to build fingerprinting map. We need to verify that received signal of WAP(wireless access point) is similar at all times in a similar space in order to solve these problems. This paper proposes a plan that is able to build fingerprinting map by using the received signal data of WAP. To do this, change the positon of WAP in the same space, It is confirmed the process of change of the RSSI corresponding to the distance. We also confirmed that the RSSI collected from elsewhere in the space a similar change in the same manner.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.3
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• pp.483-488
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• 2019

The propagation prediction model of the earth-space communication link used as an international standard was used to calculate and analyze the total losses on the communication path. The standard definition and scope of ITU-R Rec. were analyzed for each parameter(rain, scintillation, atmospheric gas, clouds) used to calculate the total loss. The total losses were calculated using the standard model for each parameter and the statistical data provided by ITU-R, and the results were analyzed using the validation examples data. The rain losses were calculated using long-term local rainfall attenuation statistics data measured in the region, and compared with the calculation results using a rainfall map in the ITU-R Recommendation. The data of Cheollian satellites for the L-Band and Ka-Band were used to calculate the rainfall attenuation. In the range of 0.01% to 0.1%, it was found to have a greater attenuation slope when using local data than attenuation by the model of ITU-R.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.4
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• pp.231-236
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• 2016

A three-electrode type reflective display (electronic paper) is designed to apply an independent electric field to each three electrodes of the cell including two electric-type of particles and electrically neutral color fluid, so single color realization is possible. In particular, the movement of particles and optical properties are decided by the electric field between two electrodes on the lower substrate. So, the effect of electric field by the distance between two electrodes on the lower substrate is studied with electrode spacing with $10{\mu}m$, $15{\mu}m$, $20{\mu}m$, and $25{\mu}m$. By our experimentation, the driving voltage induces more reliable movement of charged particles and the optical properties as compared with the threshold voltage. We ascertain the single color realization and non-inverted particle separation is possible. So the more desirable optical properties are observed in case of the short electrode like $10{\mu}m$.

• Bulletin of the Korean Chemical Society
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• v.20 no.11
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• pp.1281-1287
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• 1999

The low-lying electronic states of diazirine and 3,3'-dimethyldiazirine have been studied by high level ab initio quantum chemical methods. The equilibrium geometries of the ground state and the first excited singlet and triplet states have been optimized using the Hartree-Fock (HF) and complete active space SCF (CASSCF) methods, as well as using the Møller-Plesset second order perturbation (MP2) theory and the single configuration interaction (CIS) theory. It was found that the first excited singlet state is of 1 B1 symmetry resulting from the n- π* transition, while the first excited triplet state is of 3 B2 symmetry resulting from the π- π* transition. The harmonic vibrational frequencies have been calculated at the optimized geometry of each electronic state, and the scaled frequencies have been compared with the experimental frequencies available. The adiabatic and vertical transition energies from the ground electronic state to the low-lying electronic states have been estimated by means of multireference methods based on the CASSCF wavefunctions, i.e., the multiconfigurational quasidegenerate second order perturbation (MCQDPT2) theory and the CASSCF second-order configuration interaction (CASSCF-SOCI) theory. The vertical transition energies have also been calculated by the CIS method for comparison. The computed transition energies, particularly by MCQDPT2, agree well with the experimental observations, and the electronic structures of the molecules have been discussed, particularly in light of the controversy over the existence of the so-called second electronic state.

• Current Optics and Photonics
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• v.7 no.2
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• pp.183-190
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• 2023

Three-dimensional (3D) displays provide a significant advantage over traditional 2D displays by offering realistic images, and table-style displays in particular are ideal for generating 3D images that appear to float above a table. These systems are based on multiview displays, and are typically operated using temporal or spatial multiplexing methods to expand the viewing zone (VZ). The VZ is an expanded space that results from merging the sub-viewing zones (SVZs) from which an individual view is made. To increase the viewing angle, many SVZs are usually required. In this paper, we propose a table-ornament electronic holographic display that utilizes 3f parabolic mirrors. In holography, the VZ is not simply expanded but synthesized from SVZs to implement continuous motion parallax. Our proposed system is small enough to be applied as a table ornament, in contrast to traditional tabletop displays that are large and not easily portable. By combining multiview and holographic technologies, our system achieves continuous motion parallax. Specifically, our system projects 340 views using a time-multiplexing method over a range of 240 degrees.

• Proceedings of the IEEK Conference
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• 2004.08c
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• pp.596-599
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• 2004

We propose an Alamouti-like scheme for combining space-time block coding with single-carrier frequency-domain equalization(SC-FDE) in fixed broadband wireless access environment. With two transmit antennas, the scheme is shown to achieve significant diversity gains at low complexity over frequency-selective fading channels

• Electrical & Electronic Materials
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• v.4 no.1
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• pp.53-64
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• 1991

절연체중에 있는 하전입자의 거동은 절연재료의 특성에 많은 영향을 준다. 본 연구에서는 호핑모델에 의한 수치해석법을 TSC특성과 쌍극자분극에 대한 TSC특성은 차이가 있었다. 실험과 대응시켜 가동이온에 관한 물성정수의 평가를 하였다. 호핑모델에 의해서 불포화 TSC와 I-V특성의 수치계산을 하였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1995.05a
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• pp.107-110
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• 1995

Space charge formation in epoxy/silica composites has been investigated by the pulsed electroacoustic (PEA) method. The addition of silica resulted in homocharge formation, which attributed to the interfacial trapping of injected charge at epoxy/silica interfaces, Homocharge accumulation with increase of voltage and silica content.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.897-900
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• 2001

Space charge distributions in silane crosslinked polyethylene (SXLPE)/ crosslinked polyethylene (XLPE) laminates was investigated using a pulsed electroacoustic (PEA) method. XLPE shows heterocharge while SXLPE shows homocharge. Positive charge is accumulated at the interface of SXLPE/XLPE laminate when applied electric field is more than 20 kV/mm. The charge profile at various temperatures was also acquired using temperature-controllable PEA system. Although applied electric field is only 8.6 kV/mm, positive interfacial charge starts to appear near 50$^{\circ}C$.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07a
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• pp.217-220
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• 2005

To find the optimal expansion of the color gamut of a display, we investigated various 4-primary display systems based on DLP. Via comparing the volume of the color gamut in a 3-D uniform color space CIELUV, the best 4-primary system on the premise of keeping the existing three primaries is brought forward.