• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.127-131
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• 2007

A laboratory study on low frequency noise assessment was carried out to determine the acceptability limits in the frequency range between 20 and 200 Hz. The acceptability limits were tested in the anechoic chamber to minimize the background noise. A total of 30 test subjects, who were aged between 19 to 33 years, participated in this study. They were exposed to various stimuli for about 1 hour by supra-aural earphone. The experiment consisted of two listening sessions; hearing threshold and the acceptability limits session. The results showed that the trend of the acceptability limits curve was approximately equal to C-weighting curve which had been found to be superior to A-weighting curve in low frequency noise assessment.

• Journal of Radiation Protection and Research
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• v.45 no.1
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• pp.11-15
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• 2020

Background: There have been various studies to investigate the mechanisms of DNA damage from low-energy electrons. To understand the mechanism of these strand breaks, it is necessary to investigate the dissociation mechanism of the DNA constituents, that is, bases, sugars, and phosphates. Materials and Methods: We studied the dissociation of thymine base upon interaction with low-energy electrons. For this experiment, thymine powder was pressed onto the indium base and irradiated by 5 eV electrons. Results and Discussion: Non-irradiated and irradiated thymine samples were compared and analyzed using the X-ray photoelectron spectroscopic technique to analyze the dissociation patterns of the molecular bonds after low-energy electron irradiation of thymine. Conclusion: With 5 eV electron irradiation, C-C and N-C = O bonds are the primary dissociations that occur in thymine molecules.

• Clinical and Experimental Pediatrics
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• v.64 no.4
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• pp.172-179
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• 2021

Background: Evidence shows that fluconazole prophylaxis is an effective treatment against invasive fungal infections in preterm neonates, however, the most efficient schedule of fluconazole prophylaxis for the colonization and mortality of invasive candidiasis (IC) is unknown. Purpose: This systematic review and meta-analysis aimed to assess the efficiency of different prophylactic fluconazole schedules in controlling IC colonization, infection, and mortality in very low birth weight (VLBW) and extremely low birth weight (ELBW) infants in neonatal intensive care units. Methods: We searched the PubMed, Scopus, Embase, and Cochrane databases using the keywords "candida," "invasive candidiasis," "IC," "fluconazole prophylaxis," "preterm infants," "very low birth weight infants," "VLBW," "extremely low birth weight," and "ELBW." Results: Mortality was significantly decreased in a meta-analysis of studies using different fluconazole prophylaxis regimens. The meta-analysis also indicated a significant decrease in the incidence of IC-associated mortality in ELBW infants using the same fluconazole prophylaxis schedules. Conclusion: Future studies should explore the effectiveness of other different fluconazole prophylaxis schedules on IC colonization, infection, and mortality.

• The Korean Journal of Cytopathology
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• v.9 no.2
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• pp.139-146
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• 1998

The AutoPap 300 QC System is an automated device for the analysis and classification of conventional cervical cytology slides for quality control purpose. These studies evaluated the sensitivity of the AutoPap 300 QC System, and estimated morphologic features other than epithelial abnormality to identify a high quality control(QC) score with the AutoPap 300 QC System. The sensitivity of the AutoPap 300 QC System at 10% review rate for 210 cases of cervicovaginal cytology with low grade squamous intraepithelial lesion(LSIL) and higher grade lesion was assessed, and compared with a 10% random rescreening. The morphologic features, such as presence of endocervical component, dirty background, atrophy, abnormal ceil size, and celluiarity of single atypical cells were estimated in 45 cases of no review and 30 cases of QC review cases. The AutoPap 300 QC System identified 119(56.7%) out of 210 cases with LSIL and higher grade lesion at 10% review rate. It was more sensitive to squamous cell lesions$(50{\sim}62%)$ than to glandular lesions(10%). The dirty background and the scanty cellularity of single atypical cells were significantly related to low QC score. Conclusively, AutoPap 300 QC System is superior to human random rescreen for the identification of false negative smears. The upgrading of this device is required to enhance the defection of glandular lesion and certain Inadequate conditions of the slides.

• Journal of the Korean housing association
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• v.17 no.3
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• pp.123-131
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• 2006

This study examined types and color conditions of street views through relationship of high-storied apartment house to street components which has great visual influence on urban street view and requires harmony with street environment as background factor and conducted positive experiment with high-storied apartment houses located at housing site development districts in Gwangju Metropolitan City since 1990s in order to set applicable color ranges in designing external colors of high-storied apartment houses which became background of street view by types. Consequently, in image changes of four factors of main colors in classified street types, P, RP, R and YR colors showed high average values in naturalness, harmony and unity and GY, G, BG and B colors showed dichotomy with low average value, but image of personality showed generally low average value. RP, R and YR colors showed higher adaptability and GY, G and BG colors showed lower adaptability. It was confirmed that according to adaptability of main colors used in high-storied apartment houses by street types, there was difference of appropriate color range in street components and external colors of high-storied apartment houses by street types.

• Proceedings of the IEEK Conference
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• 2009.05a
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• pp.37-39
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• 2009

In the research of speech recognition, locating the beginning and end of a speech utterance in a background of noise is of great importance. Since the background noise presenting to record will introduce disturbance while we just want to get the stationary parameters to represent the corresponding speech section, in particular, a major source of error in automatic recognition system of isolated words is the inaccurate detection of beginning and ending boundaries of test and reference templates, thus we must find potent method to remove the unnecessary regions of a speech signal. The conventional methods for speech endpoint detection are based on two simple time-domain measurements - short-time energy, and short-time zero-crossing rate, which couldn't guarantee the precise results if in the low signal-to-noise ratio environments. This paper proposes a novel approach that finds the Lyapunov exponent of time-domain waveform. This proposed method has no use for obtaining the frequency-domain parameters for endpoint detection process, e.g. Mel-Scale Features, which have been introduced in other paper. Comparing with the conventional methods based on short-time energy and short-time zero-crossing rate, the novel approach based on time-domain Lyapunov Exponents(LEs) is low complexity and suitable for Digital Isolated Word Recognition System.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.6
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• pp.579-586
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• 2011

It is very critical for image processing of IIR (Imaging Infrared) seekers to achieve improved guidance performance for missile systems to determine appropriate thresholds in various environments. In this paper, we propose automatic threshold determination methods for proper thresholds to extract definite target signals in an EOCM (Electro-Optical Countermeasures) environment with low SNR (Signal-to-Noise Ratios). In particular, thresholds are found to be too low to extract target signals if one uses the Otsu method so that we suggest a Shifted Otsu method to solve this problem. Also we improve extracting target signal by changing Shifted Otsu thresholds according to the TBR (Target to Background Ratio). The suggested method is tested for real IIR images and the results are compared with the Otsu method. The HPDAF (Highest Probabilistic Data Association Filter) which selects the target originated measurements by taking into account of both signal intensity and statistical distance information is applied in this study.

• MALSORI
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• no.63
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• pp.125-137
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• 2007

Recently, many techniques have been proposed to improve the noise robustness for speaker verification. In this paper, we consider the feature recombination technique in multi-band approach. In the conventional feature recombination for speaker verification, to compute the likelihoods of speaker models or universal background model, whole feature components are used. This computation method is not effective in a view point of multi-band approach. To deal with non-effectiveness of the conventional feature recombination technique, we introduce a subband likelihood computation, and propose a modified feature recombination using subband likelihoods. In decision step of speaker verification system in noise environments, a few very low likelihood scores of a speaker model or universal background model cause speaker verification system to make wrong decision. To overcome this problem, a reliable feature selection method is proposed. The low likelihood scores of unreliable feature are substituted by likelihood scores of the adaptive noise model. In here, this adaptive noise model is estimated by maximum a posteriori adaptation technique using noise features directly obtained from noisy test speech. The proposed method using subband-based reliable feature selection obtains better performance than conventional feature recombination system. The error reduction rate is more than 31 % compared with the feature recombination-based speaker verification system.

• Current Optics and Photonics
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• v.4 no.3
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• pp.210-220
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• 2020

Aiming at the problem that the Local Sparse Difference Index algorithm has low accuracy and low efficiency when detecting target anomalies in a hyperspectral image, this paper proposes a Weighted Collaborative Representation and Sparse Difference-Based Hyperspectral Anomaly Detection algorithm, to improve detection accuracy for a hyperspectral image. First, the band subspace is divided according to the band correlation coefficient, which avoids the situation in which there are multiple solutions of the sparse coefficient vector caused by too many bands. Then, the appropriate double-window model is selected, and the background dictionary constructed and weighted according to Euclidean distance, which reduces the influence of mixing anomalous components of the background on the solution of the sparse coefficient vector. Finally, the sparse coefficient vector is solved by the collaborative representation method, and the sparse difference index is calculated to complete the anomaly detection. To prove the effectiveness, the proposed algorithm is compared with the RX, LRX, and LSD algorithms in simulating and analyzing two AVIRIS hyperspectral images. The results show that the proposed algorithm has higher accuracy and a lower false-alarm rate, and yields better results.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.11 no.1
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• pp.39-51
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• 2008

These days, one of the issues well discussed is the obstruction or screen of sight to mountain-skyline by buildings. So question is to which heights buildings should be constructed over mountain-skyline and then harmony can be realized between mountain-skyline and building-outline. Based on the mentioned above, this study intends to find out the proper projection- level of buildings over background mountain-skyline when considering the types of mountain-skyline, building-outline and building-layout. The results of this study are first, the proper projection-ratio of buildings over background mountain-skyline can be 0.1 because assessment values on harmony-level are more than 3.0 in almost cases, second, the building-outline influences on the assessment values of harmony-level when the types of mountain-skyline are formed left-high & right-low and right-high & left-low, third, building-layout doesn't influence on the assessment va lues of harmony-level, finally, statistically difference doesn't exist between expert group and non-expert group in the assessment values of harmony-level.