• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.45 no.12
• /
• pp.83-89
• /
• 2008

Simple but effective fast codebook searching algorithms for quantized EGT(equal gain transmission) are presented. Using newly defined metric, rough searching selects a few candidate weight vectors. Using the conventional metric, accurate searching determines the optimal vector among the candidates. This strategy reduces the entire searching time. When the number of transmit antenna is two or three, the searching time reduces more than a half less than the conventional searching time. Moreover, the more the size of codebook increases, the more the searching time reduction also increases.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.25 no.10
• /
• pp.1005-1019
• /
• 2014

In this paper, we proposed the frequency candidates band for the spectrum sharing through researching and analyzing the current status of the policy and the economic values which is actively conducted on the United States and Europe. To this end, we investigated to the status and problems with the frequency reallocation and arrangement in respond to the current frequency demand. To solve these frequency reallocation and arrangement method problems, we introduce to the concept and current status of policy for the frequency method progress by advanced countries mainly. Also the results of the economic value analysis introduced in terms of the operators. In addition, we proposed the assessment terms and criteria for the selection of frequency candidates band through joint research and analysis results.

• The KIPS Transactions:PartD
• /
• v.13D no.3 s.106
• /
• pp.377-382
• /
• 2006

Advantageous features of flash memory are stimulating its exploitation in mobile and ubiquitous related devices. The hardware characteristics of flash memory however place restrictions upon this current trend. In this paper, a cleaning policy for flash memory is proposed in order to decrease the necessary penally for recycling of memory minimizing the degradation of performance at the same time. The proposed cleaning algorithm is based on partitioning of candidate memory regions, to be reclaimed as free, into a number of groups. In addition, in order to improve the balanced utilization of the entire flash memory space in terms of 'wearing-out', a free segment selection algorithm is discussed. The impact of the proposed algorithms is evaluated through a number of experiments. Moreover, the composition of the optimal configuration featuring the proposed methods is tested through experiments.

• Journal of Microbiology and Biotechnology
• /
• v.22 no.12
• /
• pp.1749-1757
• /
• 2012

Makgeolli is a traditional rice wine favored by the general public in Korea. This study investigated the fermentation and sensory characteristics of using wild yeast strains for brewing makgeolli. A non-Saccharomyces cerevisiae strain was isolated from nuruk and termed Y197-13. It showed 98% similarity to Pichia anomala and had an optimal growth temperature of $25^{\circ}C$. Makgeolli was manufactured using koji, jinju nuruk, and improved nuruk as fermentation agents. Y197-13 makgeolli brewed with koji had alcohol and solids contents of 11.1% and 13.9%, respectively. Sweet sensory characteristics were attributed to residual sugars in makgeolli with 6% alcohol. The makgeolli had a fresh sour taste and carbonated taste. Volatile component analysis showed the isoamyl alcohol, phenylethyl alcohol, isoamyl acetate, and fatty acid, including ethyl oleate and ethyl linoleate, relative peak area was higher in Y197-13 makgeolli than in makgeolli with Saccharomyces cerevisiae. These results suggest the wild yeast, Y197-13, as a candidate for brewing makgeolli.

• The Korean Journal of Applied Statistics
• /
• v.30 no.1
• /
• pp.119-133
• /
• 2017

Corrected Akaike's information criterion (AICc) is known to have better finite sample properties. However, Akaike's information criterion (AIC) is still widely used to select an optimal prediction model among several candidate models due to of a lack of research on benefits obtained using AICc. In this paper, we compare the performance of AIC and AICc through numerical simulations and confirm the advantage of using AICc. In addition, we also consider the performance of quasi Akaike's information criterion (QAIC) and the corrected quasi Akaike's information criterion (QAICc) for binomial and Poisson data under overdispersion phenomenon.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2005.10a
• /
• pp.851-856
• /
• 2005

The precision fabrication of aspherical lenses is increasingly required for the latest applications of compact and high resolution video-recording or camera systems. Micro-optical components, including micro-spherical or aspherical lenses and reflecting mirrors, are generally required to be manufactured with high shape accuracy, extremely low surface roughness and no surface damage. To meet the needs of the precision fabrication system, a bed which supports the micro aspherical lens fabrication machines stably and safely is required. In this study, the thickness of the ribs of the bed is optimized using the CAD integrated optimal design system, a virtual DS program.

• Journal of Auto-vehicle Safety Association
• /
• v.11 no.3
• /
• pp.30-36
• /
• 2019

This paper suggests a car-following algorithm for urban environment, with multiple target candidates. Until now, advanced driver assistant systems (ADASs) and self-driving technologies have been researched to cope with diverse possible scenarios. Among them, car-following driving has been formed the groundwork of autonomous vehicle for its integrity and flexibility to other modes such as smart cruise system (SCC) and platooning. Although the field has a rich history, most researches has been focused on the shape of target trajectory, such as the order of interpolated polynomial, in simple single-lane situation. However, to introduce the car-following mode in urban environment, realistic situation should be reflected: multi-lane road, target's unstable driving tendency, obstacles. Therefore, the suggested car-following system includes both in-lane preceding vehicle and other factors such as side-lane targets. The algorithm is comprised of three parts: path candidate generation and optimal trajectory selection. In the first part, initial guesses of desired paths are calculated as polynomial function connecting host vehicle's state and vicinal vehicle's predicted future states. In the second part, final target trajectory is selected using quadratic cost function reflecting safeness, control input efficiency, and initial objective such as velocity. Finally, adjusted path and control input are calculated using model predictive control (MPC). The suggested algorithm's performance is verified using off-line simulation using Matlab; the results shows reasonable car-following motion planning.

• The Bulletin of The Korean Astronomical Society
• /
• v.44 no.1
• /
• pp.75.1-75.1
• /
• 2019

The universe has been ionized in the post-reionization by several photon contributors. The dominant source to produce the hydrogen ionizing photons is not revealed so far. Faint quasars have been expected to generate UV photon budgets required to maintain ionization state of universe. Observational limits, however, hinder to discover them despite their higher number density than bright one. Consequently, the influence of faint quasars on post-reionization are not considered sufficiently. Therefore, a survey to find faint quasars at z ~ 5 is crucial to determine the main ionizing source in the post-reionization era. Deep images from the Hyper Suprime-Cam Subaru Strategic Program (HSC SSP) allow us to search for quasar swith low luminosities in the ELAIS-N1 field. J band information are obtained by the Infrared Medium-deep Survey (IMS) and the UKIRT Infrared Deep Sky Survey (UKIDSS) - Deep ExtragalacticSurvey (DXS). Faint quasar candidates were selected from several multi-band color cut criteria based on simulated quasars on color-color diagram. To choose the reliable candidates with possible Lyman break, we have performed medium-bands observations. Whether a candidate is a quasar or a dwarf star contamination was decided by results from chi-square minimization of quasar/dwarf model fitting. Spectroscopic follow-up observations confirm three quasars at z ~ 5. 100% spectral confirmation success rate implies that the medium-band observations effectively select faint quasars with strong Lyman alpha emission.

• The Bulletin of The Korean Astronomical Society
• /
• v.43 no.2
• /
• pp.53.2-53.2
• /
• 2018

We present newly discovered dwarf galaxy candidates in deep and wide-field images of NGC 1291 obtained with KMTNet. Through a visual inspection, we find ~ 13 candidates, for which central surface brightness ranges from ${\mu}_{0,R}{\sim}22.5$ to $26.5mag\;arcsec^{-1}$. Adopting the distance to NGC 1291, the candidate dwarfs are brighter than $M_R=-12.5mag$ and their effective radii range from 350 pc to 1.4 kpc. Structural and photometric properties of dwarf candidates near NGC 1291 appears to be consistent with those of ordinary dwarf galaxies in nearby galaxies. We conduct the imaging simulation in order to find an optimal way to detect dwarf galaxies in KMTNet images and to test the completeness of our detection algorithm. We plan to apply this method to deep KMTNet images of other nearby galaxies obtained through KMTNet Nearby Galaxy Survey (KNGS).

• The Journal of the Convergence on Culture Technology
• /
• v.7 no.3
• /
• pp.565-570
• /
• 2021

A soft-decision decoding scheme of a channel code for correcting an error occurring in a receiver of a digital communication systems is proposed. A method for efficiently decoding by use of the linear and arithmetic structure of linear block codes is presented. In this way, the probability of decoding errors has been reduced. In addition, it is possible to reduce the complexity of decoding as well. Sufficient conditions for achieving optimal decoding has been derived. As a result, the sufficient conditions enable efficient search for candidate codewords. With the proposed decoding scheme, we can effectively perform the decoding while lowering the block error probability.