• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.11A
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• pp.1124-1131
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• 2008

In this paper, we propose a timing synchronization scheme and its hardware architecture of the next generation IEEE 802.11n wireless LAN standard which is based on MIMO-OFDM technique. Proposed timing synchronization method takes two steps which consist of two modified auto-correlators. For coarse timing synchronization, a sliding window differentiator is used after a conventional auto-correlation in order to avoid plateau problem. The conjugate symmetry property of L-LTS is utilized for the simplification of fine timing synchronization. Since cross-correlation based methods are not required, the computational complexity and the number of multipliers can be reduced. In order to reduce the hardware complexity, we have used sign multipliers. Based on simulation results, the proposed method outperforms a conventional method. The proposed scheme can be applied to IEEE 802.11n systems and can easily be expanded to frequency synchronization scheme.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.35 no.5
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• pp.367-371
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• 2009

Purpose: The purpose of this study was to evaluate the feasibility of the outfracture osteotomy sinus graft technique with the evaluation of 5-year survival rate of the implants placed in the atrophic edentulous posterior maxillary area. Materials and methods: One hundred and thirteen cases of 96 patients who visited our center from Aug 2004 to July 2009 and were diagnosed as atrophic edentulous maxillary alveolar ridge, were selected and underwent augmentation sinus surgery with outfracture osteotomy technique. Feasibility of the outfracture osteotomy technique was investigated with clinical and radiographic evaluation to assess the survival rate of the total dental implants in augmentation sinus surgery of this new kind. Total fixture number available in follow-up period was 179, in which the lost 10 patients were excluded out of 96 patients. Results: Five-year cumulative survival rate was 97.2% with 5 failures of total 179 fixtures. The average follow-up period was 29 and a half months, with the minimum and maximum follow-up periods of 4 months 21 days and 59 months 14 days, respectively. Conclusion: Traditional infracture technique is a popular method for an augmentation sinus surgery. The authors modified this classical method by outfracturing and readapting the bony window after sinus graft, with excellent treatment results evidenced by high survival rate of 97.2% (174 out of 179 fixtures), which proves the feasibility of the newly-designed outfracture osteotomy sinus graft technique.

• The Journal of the Acoustical Society of Korea
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• v.14 no.1
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• pp.31-39
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• 1995

In this paper, we have constructed phoneme discriminant filters [PDF] according to the linear discriminant function. These discriminant filters do not follow the heuristic rules by the experts but the mathematical methods in iterative learning. Proposed system. is based on the piecewise linear classifier and error correction learning method. The segmentation of speech and the classification of phoneme are carried out simutaneously by the PDF. Because each of them operates independently, some speech intervals may have multiple outputs. Therefore, we introduce the unified coefficients by the output unification process. But sometimes the output has a region which shows no response, or insensitive. So we propose time windows and median filters to remove such problems. We have trained this system with the 549 monosyllables uttered 3 times by 3 male speakers. After we detect the endpoint of speech signal using threshold value and zero crossing rate, the vowels and consonants are separated by the PDF, and then selected phoneme passes through the following PDF. Finally this system unifies the outputs for competitive region or insensitive area using time window and median filter.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.41 no.6
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• pp.9-18
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• 2004

This paper proposes a new and simple stereo matching algorithm using the disparity space image (DSI) technique. First of all, we detect some salient feature points on each scan-line of the image pair and set the matching area using those points and define a simple cost matrix. And we take advantage of matching by pixel-by-pixel instead of using the matching window. While the pixel-by-pixel method boost up the speed of matching, because of no using neighbor information, the correctness of the matching may not be better. To cover this point, we expand the matching path using character of disparity-space-image for using neighbor information. In addition, we devise the compensated matching module using the volume of the disparity space image in order to improve the accuracy of the match. Consequently, we can reduce mismatches at the disparity discontinuities and can obtain the more detailed and correct disparity map.

• Journal of Digital Contents Society
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• v.16 no.2
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• pp.335-343
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• 2015

This paper describes a quantitative approach to the BIM-enabled assessment of building circulation by using quantitative data and applying its weight. Assessment of building circulation plays an important role before construction stage because of related requirements regulated by design guide, building codes, etc. and design decision making as well. In this paper, Qualitative issue is mainly dealt with that are usually excluded from rule checking objects due to their implicit definition such as 'comfortable circulation'. A weighting framework is suggested using weighted data of circulation properties such as 1) metric distance, 2) number of passing spaces, 3) number of turning spaces, 4) window area of passing space, etc.

• Korea Journal of Hospital Management
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• v.18 no.3
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• pp.27-42
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• 2013

Purpose: This study is aimed to provide the fundamental data for building the patient safety culture by identifying the perceptions of patient safety culture of hospital nurses. Methods: this study was a cross-sectional survey. For this study, 816 nurses participated from three general hospital and one university hospital located in Gwangju and Chonnam. The data were collected from April to June, 2012 by self-administrated questionnaires. The 'Hospital Survey on Patient Safety Culture'developed AHRQ(2004) and translated in Korean and edited by Je(2006), was used to measure the patient safety culture which the nurses were perceived. The collected data were analyzed with descriptive statistics, t-test, ANOVA, Scheffe test using SPSS window 18.0. Results: With a possible score of 5 points, the average score for nurses'perceived patient safety culture 3.32. In the sub dimension of patient safety culture, the score hospital-level aspects was the highest level of 3.27(0.50) and reporting system medical errors was the lowest of 3.08(0.40). The difference of perception level on patient safety culture were statistically significant depending on demographic and job-related characteristics such as age, hospital level, work experience in present hospital, work experience in present unit, work experience in present area, positions, work hours of week. Conclusion: The scores of perception of which were shown to be relatively low in this study, needed to be improved through continuous education, evaluation and researches. We suggest developing a new tool on patient safety culture fit our country which will help to manage ongoing patient safety culture.

• Proceedings of the Korea Information Assurance Society Conference
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• 2004.05a
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• pp.327-331
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• 2004

The new cyber world has created by Internet that is prosperous rapidly. But with the expansion of Internet the hacking and intrusion are also increased very much. Actually there were many incidents in Internet, but the damage was restricted within a local area and local system. However, the Great 1.25 Internet Disturbance has paralyzed the national wide Internet environment. It because the Slammer Worm. The worm is a malformed program that uses both of the hacking and computer virus techniques. It autonomously attacks the vulnerability of Windows system, duplicates and spreads by itself. Jus like the Slammer Worm, almost every worms attack the vulnerability of Windows systems that installed in personal PC. Therefore, the vulnerability in personal PC could destroy the whole Internet world. So, in this paper we propose a Internet Worm Expanding Prevention System that could be installed in personal PC to prevent from expanding the Internet Worm. And we will introduce the results of developed system.

• KIEAE Journal
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• v.16 no.3
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• pp.113-119
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• 2016

Purpose: In this study, we evaluate the annual energy performance of the detached house which was designed with the aim of zero energy. Method: The experimental house which was constructed in Gonju Chungnam in 2013, is the single family detached house of light weight wood frame with $100m^2$ of heating area. Thermal transmittance of roof (by ISO 10211) and building external walls are designed as $0.10W/m^2K$ and $0.14W/m^2$ respectively and low-e coating vacuum window glazing with PVC frame was installed. Also grid connected PV system and natural-circulation solar water heater was applied and 6kWp capacity of photovoltaic module was installed in pitched roof and $5m^2$ of solar collector in vertical wall facing the south. We analyzed the 2014 annual data of the detached house in which residents were actually living, measured though web-based remote monitoring system. Result: First, as a result, total annual energy consumption and energy production (PV generation and solar hot water) are 7,919kWh and 7,689kWh respectively and the rate of energy independence is 97.1% which is almost close to the zero energy. Second, plug load and hot water of energy consumption by category showed the highest numbers each with 33% and 31%, with following space heating 24%, electric cooker 8%, lighting 3% in order. Hot water supply is relatively higher than space heating because high insulation makes it decreased.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.8C
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• pp.505-515
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• 2011

This paper describes a normalization method of Haar-like features used for object detection. Previous method which performs variance normalization on Haar-like features requires a lot of calculations, since it uses an additional integral image for calculating the standard deviation of intensities of pixels in a candidate window and increases possibility of false detection in the area where variance of brightness is small. The proposed normalization method can be performed much faster than the previous method by not using additional integral image and classifiers which are trained with the proposed normalization method show robust performance in various lighting conditions. Experimental result shows that the object detector which uses the proposed method is 26% faster than the one which uses the previous method. Detection rate is also improved by 5% without increasing false alarm rate and 45% for the samples whose brightness varies significantly.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.2
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• pp.104-110
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• 2001

Structural, optical and electrical properties of Cd$_{1-x}$ Zn$_{x}$S films deposited by chemical bath deposition(CBD), which is a very attractive method for low-cost and large-area solar cells, are presented. Especially, in order to control more effectively the zinc component of the films, zinc acetate, which was used as the zinc source, was added in the reaction solution after preheating the reaction solution and the pH of the reaction solution decreased with increasing the concentration of zinc acetate. The films prepared after preheating and pH control had larger zinc component and higher optical band gap. The crystal structures of Cd$_{1-x}$ Zn$_{x}$S films was a wurtzite type with a preferential orientation of the (002) plane and the lattice constants of the films changed from the value for CdS to those for ZnS with increasing the mole ratio of the zinc acetate. The minimum lattice mismatch between Cd$_{1-x}$ Zn$_{x}$S and CdTe were 2.7% at the mole ratio of (ZnAc$_2$)/(CdAc$_2$+ZnAc$_2$)=0.4. As the more zinc substituted for Cd in the films, the optical transmittance improved, while the absorption edge shifted toward a shorterwavelength. the photoconductivity of the films was higher than the dark conductivity, while the ratio of those increased with increasing the mole ratio of zinc acetate. acetate.