• Korean Journal of Optics and Photonics
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• v.22 no.5
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• pp.223-229
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• 2011

We present a low jitter frequency up-conversion detector based on quasi-phase matched sum frequency generation in a periodically poled $LiNbO_3$ waveguide for efficient single-photon detection at 1.5 ${\mu}m$ telecommunication wavelengths. The maximum detection efficiency and the noise count rate using the pump power of 300 mW and the pump wavelength of 974 nm are about 7% and 480 kHz, respectively. We also characterize the timing jitter of the frequency up-conversion detector by analyzing the time distribution of the detection outputs for photons generated through a picosecond pump pulsed spontaneous parametric downconversion. The minimum timing jitter was measured to be about 39.1 ps. Coincidence measurement with a narrow time window for pulsed up-conversion photons can eliminate the unwanted noise counts and maximize signal to noise ratio.

• Radiation Oncology Journal
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• v.36 no.4
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• pp.276-284
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• 2018

Purpose: Traditionally, three-dimensional conformal radiation therapy (3D-CRT) is used for neoadjuvant chemoradiation in locally advanced rectal cancer. Intensity-modulated radiation therapy (IMRT) was later developed for more conformal dose distribution, with the potential for reduced toxicity across many disease sites. We sought to use the National Cancer Database (NCDB) to examine trends and predictors for IMRT use in rectal cancer. Materials and Methods: We queried the NCDB from 2004 to 2015 for patients with rectal adenocarcinoma treated with neoadjuvant concurrent chemoradiation to standard doses followed by surgical resection. Odds ratios were used to determine predictors of IMRT use. Univariable and multivariable Cox regressions were used to determine potential predictors of overall survival (OS). Propensity matching was used to account for any indication bias. Results: Among 21,490 eligible patients, 3,131 were treated with IMRT. IMRT use increased from 1% in 2004 to 22% in 2014. Predictors for IMRT use included increased N stage, higher comorbidity score, more recent year, treatment at an academic facility, increased income, and higher educational level. On propensity-adjusted, multivariable analysis, male gender, increased distance to facility, higher comorbidity score, IMRT technique, government insurance, African-American race, and non-metro location were predictive of worse OS. Of note, the complete response rate at time of surgery was 28% with non-IMRT and 21% with IMRT. Conclusion: IMRT use has steadily increased in the treatment of rectal cancer, but still remains only a fraction of overall treatment technique, more often reserved for higher disease burden.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.44 no.6
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• pp.16-23
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• 2007

Changeable biometrics has been developed as a solution to problem of enhancing security and privacy. The idea is to transform a biometric signal or feature into a new one for the purposes of enrollment and matching. In this paper, we propose a changeable biometric system that can be applied to appearance based face recognition system. In the first step when using feature extraction, ICA(Independent Component Analysis) coefficient vectors extracted from an input face image are replaced randomly using their mean and variation. The transformed vectors by replacement are scrambled randomly and a new transformed face coefficient vector (transformed template) is generated by combination of the two transformed vectors. When this transformed template is compromised, it is replaced with new random numbers and a new scrambling rule. Because e transformed template is generated by e addition of two vectors, e original ICA coefficients could not be easily recovered from the transformed coefficients.

• Korean Journal of Clinical Pharmacy
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• v.28 no.2
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• pp.107-116
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• 2018

Objective: This study analyzed the national claims data of veterans to generate scientific evidence of the trends and appropriateness of their drug utilization in an outpatient setting. Methods: The claims data were provided by the Health Insurance Review & Assessment (HIRA). Through sampling and matching data, we selected two comparable groups; Veterans vs. National Health Insurance (NHI) patients and Veterans vs. Medical Aid (MAID) patients. Drug use and costs were compared between groups by using multivariate gamma regression models to account for the skewed distribution, and therapeutic duplication was analyzed by using multivariate logistic regression models. Results: In equivalent conditions, veteran patients made fewer visits to medical institutions (0.88 vs. 1), had 1.86 times more drug use, and paid 1.4 times more drug costs than NHI patients (p<0.05); similarly, veteran patients made fewer visits to medical institutions (0.96 vs. 1), had 1.11 times more drug use, and paid 0.95 times less drug costs than MAID patients (p<0.05). The risk of therapeutic duplication was 1.7 times higher (OR=1.657) in veteran patients than in NHI patients and 1.3 times higher (OR=1.311) than in MAID patients (p<0.0001). Conclusion: Similar patterns of drug use were found in veteran patients and MAID patients. There were greater concerns about the drug use behavior in veteran patients, with longer prescribing days and a higher rate of therapeutic duplication, than in MAID patients. Efforts should be made to measure if any inefficiency exists in veterans' drug use behavior.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.7
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• pp.732-739
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• 2002

Performance of the applicator for hyperthermia is determined by both the degree of impedance matching and specific absorption rate(SAR) distribution in the surrounding tissue. In this paper, the coaxial-slot antenna using staircasing approximation in the FDTD is analyzed and the coaxial-slot antenna for the hyperthermia improving heating characteristics is designed. The SAR of the coaxial-slot antenna approximated to staircasing and square model is analyzed, and the SAR of staircasing model is compared with Saito's SAR measurement and square model. As a result, the SAR of proposed model exhibited agreement with the Saito's measurement of square model. Ig averaged SAR on the liver caused by proposed antenna in this paper is 195 W/kg, and is about 27.9 % higher than the Saito's antenna 152.5 W/kg, respectively.

• Korean Journal of Social Welfare
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• v.65 no.1
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• pp.201-226
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• 2013

This study aims to identify changes in early work career of youth cohort entering the labor market pre and post-the economic crisis and compare career pathway types of different cohorts. Labor market experiences of youth cohort were constructed by sequencing the number of organizations, kinds of jobs, the scale of the business, and type of employment. In addition, a holistic sequence was created by including complementary factors. In this sense, the labor market experience in this study was conceptualized as a process involving continuous sequences and hierarchical and orderly changes which differs from a simple job mobility. Sequence analysis involving Optimal Matching method was conducted to examine whether such cohort-differences in labor market experiences were related to differences in distribution of career pathway types. The result showed that the post-economic crisis cohort had a relatively higher likelihood of falling into the non-employment type, unemployment type, non-corporate employment type, irregular employment type, and mobile employment type. These findings provide empirical evidence supporting the hypothesis that the employment precariousness of cohort has exacerbated after the economic crisis.

• KIPS Transactions on Software and Data Engineering
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• v.5 no.9
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• pp.401-410
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• 2016

3D registration is a computer vision technique of aligning multi-view range images with respect to a reference coordinate system. Various 3D registration algorithms have been introduced in the past few decades. Iterative Closest Point (ICP) is one of the widely used 3D registration algorithms, where various modifications are available nowadays. In the ICP-based algorithms, the closest points are considered as the corresponding points. However, this assumption fails to find matching points accurately when the initial pose between point clouds is not sufficiently close. In this paper, we propose a new method to solve this problem using the 6D distance (3D color space and 3D Euclidean distances). Moreover, a color segmentation-based adaptive sampling technique is used to reduce the computational time and improve the registration accuracy. Several experiments are performed to evaluate the proposed method. Experimental results show that the proposed method yields better performance compared to the conventional methods.

• Korean Journal of Agricultural Science
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• v.47 no.2
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• pp.315-326
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• 2020

In this study, a real-time crop recognition system was developed for an unmanned farm machine for upland farming. The crop recognition system was developed based on a stereo camera, and an image processing framework was proposed that consists of disparity matching, localization of crop area, and estimation of crop height with coordinate transformations. The performance was evaluated by attaching the crop recognition system to a tractor for five representative crops (cabbage, potato, sesame, radish, and soybean). The test condition was set at 3 levels of distances to the crop (100, 150, and 200 cm) and 5 levels of camera height (42, 44, 46, 48, and 50 cm). The mean relative error (MRE) was used to compare the height between the measured and estimated results. As a result, the MRE of Chinese cabbage was the lowest at 1.70%, and the MRE of soybean was the highest at 4.97%. It is considered that the MRE of the crop which has more similar distribution lower. the results showed that all crop height was estimated with less than 5% MRE. The developed crop recognition system can be applied to various agricultural machinery which enhances the accuracy of crop detection and its performance in various illumination conditions.

• Smart Media Journal
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• v.4 no.3
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• pp.50-55
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• 2015

In this paper, we present background modeling method based on Gaussian mixture model to subtract background for night-time video surveillance. In night-time video, it is hard work to distinguish the object from the background because a background pixel is similar to a object pixel. To solve this problem, we change the pixel of input frame to more advantageous value to make the Gaussian mixture model using scaled histogram stretching in preprocessing step. Using scaled pixel value of input frame, we then exploit GMM to find the ideal background pixelwisely. In case that the pixel of next frame is not included in any Gaussian, the matching test in old GMM method ignores the information of stored background by eliminating the Gaussian distribution with low weight. Therefore we consider the stacked data by applying the difference between the old mean and new pixel intensity to new mean instead of removing the Gaussian with low weight. Some experiments demonstrate that the proposed background modeling method shows the superiority of our algorithm effectively.

• Journal of Pharmacopuncture
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• v.10 no.2 s.23
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• pp.5-18
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• 2007

Objectives : The purpose of this study was to obtain an objective differentiating method for various types of Panax ginseng: ginseng, cultivated wild ginseng, and natural wild ginseng which are distinctive according to their growing environment. Methods : The roots, stem, and leaves of several types of ginseng were collected and comparative analysis of proteome was conducted on each part using 2-DE and the results examined. Results : 1. Proteome images of the respective parts within the samples showed spot-matching in most cases, suggesting that they are genetically identical panax ginseng. 2. Similar distribution patters were seen within the different parts of the Panax ginseng: ginseng, Chinese cultivated wild ginseng, and the 5 and 10 years old Korean cultivated wild ginseng. 3. For a quantitative evaluation of spots showing differences among the samples, 102 spots from the roots, 109 spots from the stems, and 132 spots form the leaves which showed a difference were selected and centrifugal identification was conducted. 4. Peculiar proteins from each respective part of the Panax ginseng were identified and the top 20 spots with significant differences were selected and analyzed in order to provide a differentiation rate among the samples. The accuracy rate ranged between 23.0-38.8%. 5. Differentiation rate of the top 10 spots with significant differences showed a 50-85% accuracy rate, and the differentiation rate was especially high for the stem of Chinese cultivated wild ginseng and Korean cultivated wild ginseng.