• Journal of the Institute of Electronics Engineers of Korea SP
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• v.45 no.6
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• pp.78-87
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• 2008

Digital image find own level core media in multimedia as image restoration technology fields, which remove degradation factor for image enhancement, have been growing. Linear space-invariant image restoration algorithm often introduce ringing artifacts near sharp intensity transition areas. This paper presents a new adaptive post-filtering algorithm for reducing ringing artifact. The proposed method extracts an edge map of the image using wavelet transform Based on the edge information, ringing artifacts are detected, and removed by an adaptive bilateral filter. Experimental results show that the proposed algorithm can efficiently remove ringing artifacts with edge preservation.

• Phonetics and Speech Sciences
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• v.3 no.1
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• pp.125-134
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• 2011

The current study investigated the effects of experience of deaf speech, severity of speaker's articulation, and linguistic cues on speech intelligibility of congenitally deafened adults with cochlear implants. Speech intelligibility was judged by 28 experienced listeners and 40 inexperienced listeners using a word transcription task. A three-way (2 $\times$ 2 $\times$ 4) mixed design was used with the experience of deaf speech (experienced/inexperienced listener) as a between-subject factor, the severity of speaker's articulation (mild to moderate/moderate to severe), and linguistic cues (no/phonetic/semantic/combined) as within-subject factors. The dependent measure was the number of correctly transcribed words. Results revealed that three main effects were statistically significant. Experienced listeners showed better performance on the transcription than inexperienced listeners, and listeners were better in transcribing speakers who were mild to moderate than moderate to severe. There were significant differences in speech intelligibility among the four different types of cues, showing that the combined cues provided the greatest enhancement of the intelligibility scores (combined > semantic > phonological > no). Three two-way interactions were statistically significant, indicating that the type of cues and severity of speakers differentiated experienced listeners from inexperienced listeners. The current results suggested that the use of a combination of linguistic cues increased the speech intelligibility of congenitally deafened adults with cochlear implants, and the experience of deaf speech was critical especially in evaluating speech intelligibility of severe speakers compared to that of mild speakers.

• Publications of The Korean Astronomical Society
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• v.30 no.2
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• pp.61-64
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• 2015

The brightness of Io's magnetic footprint, an indicator of electromagnetic interaction at the satellite, appears to be strongly connected to the satellite's distance from the plasma equator. As a result, the brightest footprints were detected when Io is near the interception location between the satellite's orbital plane and the plasma equator. However, volcanic activities on Io show strong correlation with the equatorward shift of Jupiter's main auroral oval, consequently causing the disappearance of Io's footprint. The same conclusion was suggested via the observation of Jupiter's hectometric radio emission, called HOM, which closely corresponds to Jupiter's auroral activity. The plasma environment near the Jovian satellites was found to vary significantly at different observational epochs. The electron density increased by approximately a factor of three from the Voyager epoch (1979) to the Galileo epoch (1995), while the electron density was found to be significantly higher (~ 5 times) in the Cassini epoch (2001). In this current study, the magnetic footprints were clearly brighter ten years ago (from peak brightness in 1998-2001) than the footprints detected in 2007. For volcanic activities on Io in 2007, there are two clear activities in February and late May. The magnetic footprint appeared to be dimmer in March 2007, expected to be the result of volcano activities in Feb 2007. However, the magnetic footprint brightness in June appeared to be slightly brighter than the footprints observed in May. The reason could be the time delay between the brightening of the sodium nebula on approximately May 31st and, a while later, the enhancement of flux tube content peaking on approximately June 5th. On the other hand, Io's magnetic footprints were observed during June 1st - 10th when they may not yet have been affected by the increase in mass outflow due to the increase of plasma density.

• The Journal of the Acoustical Society of Korea
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• v.20 no.1
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• pp.21-29
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• 2001

In order to detect the precise port/starboard direction of arrival of target signal in real noisy ocean environments, Inverse beamforming (IBF) algorithm is surveyed theoretically and the detection performances of IBF are analyzed with simulations. Cardioid Inverse beamforming algorithm was proposed for port/starboard discrimination and the performance was studied with simulations. It is shown that IBF has a 3dB array gain advantage over Conventional beamforming (CBF) under ideal conditions. This 3 dB advantage is proven theoretically and illustrated with simulations. The fact that the IBF beamwidth is narrower than the CBF beamwidth by a factor of 0.68 proves the performance of defection and spatial resolution improvement. Comparing the simulation results of Cardioid Inverse beamforming and Conventional Cardioid beamforming, it is shown that Cardioid Inverse beamformer has enhanced performance in minimum detection level, detection accuracy and resolution. Due to the results of moving target bearing detection test in endfire, it is shown that Cardioid Inverse beamformer has better performance, comparing the Conventional Cardioid beamformer.

• Journal of the Korean Vacuum Society
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• v.17 no.4
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• pp.346-352
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• 2008

Eu sites and the effect of Mg codoping were investigated in Eu-implanted GaN films. Photoluminescence (PL) and PL excitation spectroscopies were performed on 620nm $^5D_0\;{\rightarrow}\;^7F_2$ Eu ionic level transition and revealed the existence of 4 different Eu sites including the known 2 sites. PL intensity from one of the sites increased by a factor of 1.6 by the Mg-codoping. The enhancement of PL by Mg-codoping was less pronounced than Er- and Nd-implanted GaN, in which the trap-mediated energy transfer dominates. In GaN:Eu the above-gap excitation transfers the energy directly to the Mg related Eu site.

• Journal of the Korea Institute of Building Construction
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• v.13 no.4
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• pp.351-359
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• 2013

Blast furnace slag (BFS) have many advantages that are related to effective value improvement on applying to concrete while side effects of blast furnace slag also appear. Thus, research team conducted an experiment with high volume slag to see if the attribute of waste alkali accelerator for mixing rate, mixed use of NaOH and $Na_2SiO_3$, and early strength agent for mixing rate for replacement ratio and for the types of the stimulants in order to increase the use of blast furnace slag1s powder. As the result of the experiment, when it comes to compression strength, all of the alkali stimulants have been improved as the replacement rate increases except for sodium hydroxide. Among the alkali stimulants, sodium silicate was high on dynamic elastic modulus and absorption factor. In case of early strength agent, the mix of mixing 1.5% and blast furnace slag 75% have showed high strength enhancement. In event of Waste Alkali accelerator, it has showed different consequences for each experiment.

• Journal of the Korean Society for Library and Information Science
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• v.21
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• pp.103-140
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• 1991

Knowledge about career patterns of women In any profession and about factors which influence these career patterns becomes increasingly necessary because of the influx of ever-increasing numbers of women into the labor force, and the need for the development and utilization of the creative productivity of women. This study alms to investigate Korean female librarians' overall career patterns and verify relevant factors which might affect to their career patterns. As an instrument, self-reported questionnaires were sent to 1,251 full-time Korean female librarians throughout the country with regular librarian's certificate, currently engaging in public, college or university, and special libraries. Based on the data gathered, the interrelationship between their career pattern inclination and its influential factors were examined through hypothesis testing. Major findings of the survey are outlined in the following: 1). Female librarians' career patterns were classified into five categories with the group represented as Categories-2 (single; wishes to continue working after marriage; places an emphasis on the sense of occupational accomplishment and social prestige) accounted for the highest proportion$(33.4\%)$. 2). The result of the hypothesis testing revealed that there is no significant relationship statistically between social factors(parents' socio-economic status, etc.) and female librarians' career patterns. So the hypothesis concerning social factors were rejected. 3). In psychological factors(job satisfaction ; self-concept sex role attitude ; role conflict ; and achievement motivation), all except for self-concept were shown to be relevant with female librarians' stable career pattern. So the hypotheses concerning psychological factors were supported. 4). According to the result of multiple discriminant analysis conducted between the above four statistically significant psychological factors and career patterns, the most influential factor for female librarians' career patterns was job satisfaction and sex role. In conclusion, the following recommendations were made: For overall enhancement of Korean female librarianship, earlier career guidance and concrete sex role education for young women is urgent which enable them to establish correct viewpoint for their occupational career female librarians themselves' constant endeavor In maintaining positive attitude toward their job is required.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.11
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• pp.2771-2778
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• 2014

In this paper, we propose an algorithm that select efficient relay nodes using information of network environment and nodes. The proposed algorithm can be used changeable weight factors as following network environment in node density. The routing protocols adopting store-carry-forward method are used for solving network problems occurred by unstable end-to-end connection in Delay Tolerant Networks(DTNs). Exiting DTN routing algorithms have problems that large latency and overhead because of deficiency of network informations. The proposed algorithm could be provide a solution this problems using changeable weight factor and prediction of network environment. Thus, selected relay nodes work efficiently in unstable and stressed network environment. Simulation results show that enhancement performance as overhead, delivery ratio, average latency compared to exiting DTN routing algorithm.

• Journal of Energy Engineering
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• v.23 no.2
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• pp.217-222
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• 2014

In order to improve the heat efficiency of the general residential boiler, we performed an experiment of condensation heat transfer to air pre-heating exchanger adhered to the condensing boiler. In this study, surface roughness was imposed on the surface of stainless steel by etching. And in order to evaluate the heat transfer performance on each plate, the counter flow heat exchanger fabricated with polycarbonate in used. As a result, on etching treated plate's overall heat transfer coefficient is higher than the original plate. And etching treated plate during 60 seconds with etchant is the to average 15% compared to bare stainless steel. And we studied the heat transfer enhancement factor through the analysis of surface characteristics using AFM.

• Journal of Microbiology and Biotechnology
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• v.27 no.9
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• pp.1649-1656
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• 2017

In simultaneous saccharification and fermentation (SSF) for production of cellulosic biofuels, engineered Saccharomyces cerevisiae capable of fermenting cellobiose has provided several benefits, such as lower enzyme costs and faster fermentation rate compared with wild-type S. cerevisiae fermenting glucose. In this study, the effects of an alternative intracellular cellobiose utilization pathway-a phosphorolytic pathway based on a mutant cellodextrin transporter (CDT-1 (F213L)) and cellobiose phosphorylase (SdCBP)-was investigated by comparing with a hydrolytic pathway based on the same transporter and an intracellular ${\beta}$-glucosidase (GH1-1) for their SSF performances under various conditions. Whereas the phosphorolytic and hydrolytic cellobiose-fermenting S. cerevisiae strains performed similarly under the anoxic SSF conditions, the hydrolytic S. cerevisiae performed slightly better than the phosphorolytic S. cerevisiae under the microaerobic SSF conditions. Nonetheless, the phosphorolytic S. cerevisiae expressing the mutant CDT-1 showed better ethanol production than the glucose-fermenting S. cerevisiae with an extracellular ${\beta}$-glucosidase, regardless of SSF conditions. These results clearly prove that introduction of the intracellular cellobiose metabolic pathway into yeast can be effective on cellulosic ethanol production in SSF. They also demonstrate that enhancement of cellobiose transport activity in engineered yeast is the most important factor affecting the efficiency of SSF of cellulose.