• Journal of the Institute of Electronics Engineers of Korea SP
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• v.42 no.2 s.302
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• pp.1-8
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• 2005

There are many image segmentation methods having bon published as the results of research so far, however these are for the noise images which can process an image under the general white noise environments. Therefore, these methods has the disadvantages because it is difficult to extract only the accurate parameters, which can distinguish between image and impulsive noise, from image with impulsive noises. So it has a problem about the potential decreasing of the performance according to the impulsive noise for all applications using the present quadtree segmentation. In this paper, we propose new quadtree segmentation using quartile deviation which can extract effectively the image information parameters from a noise image. Therefore our method can apply for various image processing fields because it has a advantage to distinguish an image information from noise image. As the result of simulation, we confirm that the proposed quadtree segmentation is more efficient than the present method when tested on impulsive noise image.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.7 no.6
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• pp.21-30
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• 2008

The travel speed collected by the prove-car equipped with the GPS has the problems, which are the data's stability and finding out the representative travel speed, by the influence of the traffic signal and etc. at the interrupted traffic. This study was conducted to develop the method of filtering the outlier data from the data collected by the prove-car. The method to remove the outlier data from the serial data which were collected by the prove-car was adapted to each of the quartile deviation statistics model and the management graphic statistics model. The rate of removing the outlier data by the quartile deviation method was $0{\sim}3.7%$ while the rate by the management graphic statistic methods was $0.3{\sim}7.2%$. Both methods show the low removal rate at the dawn time when the traffic is inactivity, on the other hand the remove rate is high during the daytime. However, both methods have the problem such that the threshold level for removing the outlier data was established at the low bound in the case as good as the statistics model. Therefore, it is required for the experience calibration.

• Journal of the Institute of Convergence Signal Processing
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• v.11 no.4
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• pp.270-277
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• 2010

The BAMS filter is a kind of wavelet shrinkage filter based on the Bayes estimators with no simulation, therefore it can be used for a real time filter. The denoising efficiency of BAMS filter is seriously affected by the estimated noise variance in each wavelet band. To remove noise in signals in existing BAMS filter, the noise variance is estimated by using the quartile of the finest level of details in the wavelet decomposition, and with this variance, the noise of the level is removed. In this paper, to remove the image noise includingodified quartile of the level of detail is proposed. And by these techniques, the image noises of mid and high frequency bands are removed, and the results showed that the increased PSNR of ab the midband noise, the noise variance estimation method using the monotonic transform and the mout 2[dB] and the effectiveness in denosing of low noise deviation images.

• Journal of Korea Water Resources Association
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• v.53 no.4
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• pp.249-258
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• 2020

Many climate studies have used the general circulation models (GCMs) for climate change, which can be currently available more than sixty GCMs as part of the Assessment Report (AR5). There are several types of uncertainty in climate studies using GCMs. Various studies are currently being conducted to reduce the uncertainty associated with GCMs, and the bias correction method used to reduce the difference between the simulated and the observed rainfall. Therefore, this study mainly considered climate change scenarios from nine GCMs, and then quantile mapping methods were applied to correct biases in climate change scenarios for each station during the historical period (1970-2005). Moreover, the monthly rainfall for the future period (2011-2100) is obtained from the RCP 4.5 scenario. Based on the bias-corrected rainfall, the standard deviation and the inter-quartile range (IQR) from the first to third quartiles were estimated. For 2071-2100, the uncertainty for the selection of GCMs is larger than that for the selection of bias correction methods and vice versa for 2011-2040. Therefore, this study showed that the selection of GCMs and the bias correction methods can affect the result for the future climate projection.

• Communications of Mathematical Education
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• v.32 no.3
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• pp.435-453
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• 2018

The results analysis of National Assessment of Educational Achievement(NAEA) can provide various implications for teaching and learning in the school field. In this study we analyzed the deviation of NAEA achievement level-based correct-answer rate and the distribution of the responses percentages for three years from 2015 to 2017 focused on multiple-choice items. First we calculated the deviation of correct-answer rate between advanced level and proficient level and between proficient level and basic level, and then we selected the items whose deviation of correct-answer rate is more than the third quartile. We explored what the content areas, behavior areas and achievement standards of each item are and what the achievement standards and characteristics of these questions are. Based on the results of the analysis, we intended to derive implications for appropriate teaching-learning methods at each achievement-level.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.10
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• pp.761-768
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• 2020

This paper explores the barriers to derivative accounting disclosures in Vietnamese companies and ranks their relative importance for effective and efficient remedies. The Delphi technique was applied to get agreement of panel of experts on the measurement of factors hindering disclosure. Unstructured questionnaires were first sent to twelve experts who had both practical experience and academic knowledge in the field to get ideas on the obstructions to derivatives disclosure. The structured questionnaire was designed to get their agreement on barriers to derivative accounting disclosures. The data analysis with mean, median, mode, standard deviation, and quartile has been implemented to ensure the unanimity. Market-related factors, legislation, accountants' attributes, managers' attributes, information technology and communication, and on-site training were the six major obstacles agreed upon by the experts during their in-depth interviews. Then, these factors were ranked by applying the analytical hierarchy process (AHP). The findings confirmed the priority of information technology and communication, which held the greatest weight. Legislation ranked second, followed by market-related factors and on-site training, which explained the impediments to derivatives disclosure. Managers' and accountants' attributes had the least contribution to the barriers to derivative disclosures. The results have important implications for actions to enhance corporate derivative disclosures in Vietnam.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.361-366
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• 2015

The objective of this paper was to establish the attributes that determines neighbourhood satisfaction in South Africa lowincome housing subsidy scheme ultilising the Delphi approach. This is because the perception and housing satisfaction of lowincome housing beneficiaries toward their housing condition can be studied by examining their satisfaction toward s the neighbourhood factors. The Delphi method was used where the views of housing experts were solicited on 26 potential attributes as identified from li terature. Consensus was achieved after three iterative rounds. The expert"s scored each attributes on a 10-point ordinal scale of impact significance, where 1-2=No impact and 9-10= very high impact. The scales adapted for consensus were: strong consensus, median 9-10, inter quartile deviation (IQD) ≤1; good consensus, median 7 ≤ 6.99and IQD≥2.1≤3. The key findings indicate that there was a good to strong consensus of 19 attributes which were key attributes that the experts perceived as determinants of neighbourhood satisfaction; while 6 other attributes had weak consensus, as they were considered to have a le sser impact in determining residents" neighbourhood satisfaction. However, attributes with weak consensus were the attributes that are highly regarded as core neighbourhood factors in other housing settings. The study contributes to the body of knowledge on th e subject where no consensus has been reached pertaining to indicators for measuring neighbourhood satisfaction in subsidised low-income housing in South Africa.

• Journal of Preventive Medicine and Public Health
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• v.41 no.5
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• pp.300-306
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• 2008

Objectives : This study was performed to compare the standardized mortality ratios among different small areas and to explore the usefulness of standardized mortality ratios in South Korea. Methods : To calculate the standardized mortality ratio (SMR), we obtained the national deaths certificate data (2004-2006) and national registration population data (2003-2006), and these were provided by the National Statistical Office. The small areas (Eup.Myoun.Dong) were based on the subdivisions of counties. Among the 3,580 small areas classified by the National Statistical Office, 3,571 areas were included in this study. The basic statistics and decile distributions of the SMRs for all the regional levels were calculated, and the small area maps were also produced for some selected regions. To evaluate the precision of SMR, we calculated the 95% confidence intervals of the SMR in selected small areas. Results : The mean and the standard deviation of the SMRs among all small areas were 100.8 and 17.0, respectively. The range was 30.6-211.7 and the inter-quartile range was 20.7. Seoul metropolitan city displayed the lowest mean SMR among 16 regions in South Korea, and 34.6 percent of the small area SMRs belonged to the first decile(the lowest group). On the contrary, the mean SMR of Gyeongsangnam province was highest, and 26.1 percent of the small area SMRs belonged to the tenth decile(the highest group). In some areas, the precision of the SMR, which was calculated by the 95% confidence intervals, remained questionable, yet it was quite stable for almost areas. Conclusions : The standardized mortality ratios can be useful for allocating health resources at the small area level in Korea.

• Environmental Analysis Health and Toxicology
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• v.29
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• pp.17.1-17.6
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• 2014

Objectives Antimicrobial chemicals are used in a variety of household and personal care products. Exposure to antimicrobial household products has been hypothesized to lead to allergic diseases in children. Methods We investigated antimicrobial household product exposure and allergic symptoms in Korean children. An antimicrobial exposure (AE) score was derived. To examine the symptoms of allergic diseases (current wheeze, current rhinitis, and current eczema) in the past 12 months, we used a questionnaire based on the core module of the International Study of Asthma and Allergies in Children. Complete data for the analysis were available for 25,805 of the 35,590 (72.5%) children. Results The prevalence of current allergic diseases was as follows: wheeze, 5.6%; allergic rhinitis, 32.6%; and eczema, 17.7%. The mean (standard deviation) AE score was 14.3 (9.3) (range: 0-40). Compared with subjects with a low AE score (reference), subjects with a high AE score (fourth quartile) were more likely to have symptoms of wheezing and allergic rhinitis (adjusted odds ratio [aOR] for wheezing 1.24, 95% confidence interval [CI], 1.05-1.45, p for trend=0.24; aOR for allergic rhinitis 1.30, 95% CI, 1.20-1.40, p <0.01). Conclusions These findings suggest that frequent use of antimicrobial household products was associated with current wheeze and current allergic rhinitis.

• Journal of Preventive Medicine and Public Health
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• v.40 no.5
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• pp.411-417
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• 2007

Objectives: Although risk factors for coronary artery disease are also associated with increased carotid intima-media thickness (IMT), there is little information available on the asymptomatic, young adult population. We examined the association between multiple cardiovascular risk factors and the common carotid IMT in 280 young Korean adults. Methods: The data used for this study was obtained from 280 subjects (130 men and 150 women) aged 25 years who participated in the Kangwha Study follow-up examination in 2005. We measured cardiovascular risk factors, including anthropometries, blood pressure, blood chemistry, carotid ultrasonography, and reviewed questionnaires on health behaviors. Risk factors were defined as values above the sex-specific 75th percentile of systolic blood pressure, body mass index, total cholesterol/ high-density lipoprotein cholesterol ratio, fasting blood glucose and smoking status. Results: The mean carotid IMT${\pm}$standard deviation observed was $0.683{\pm}0.079mm$ in men and $0.678{\pm}0.067mm$ in women (p=0.567) and the evidence of plaque was not observed in any individuals. Mean carotid IMT increased with an increasing number of risk factors(p for trend <0.001) and carotid IMT values were 0.665 mm, 0.674 mm, 0.686 mm, 0.702 mm, and 0.748 mm for 0, 1, 2, 3, and 4 to 5 risk factors, respectively. The odds ratio for having the top quartile carotid IMT in men with 3 or more risk factors versus 0-2 risk factors was 5.09 (95% CI, 2.05-12.64). Conclusions: Current findings indicate the need for prevention and control of cardiovascular risk factors in young adults and more focus on those with multiple cardiovascular risk factors.