• Journal of the Korea Institute of Information Security & Cryptology
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• v.12 no.1
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• pp.21-32
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• 2002

In this paper, for any prime q, new cyclic difference sets with Singer parameter equation omitted are constructed by using the q-ary sequences (d-homogeneous functions) of period $q_n$-1. When q is a power of 3, new cyclic difference sets with Singer parameter equation omitted are constructed from the ternary sequences of period $q_n$-1 with ideal autocorrealtion found by Helleseth, Kumar and Martinsen.

• Smart Media Journal
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• v.1 no.3
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• pp.15-21
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• 2012

Depth information is necessary for various three dimensional contents generation. Depth acquisition techniques can be categorized broadly into two approaches: active, passive depth sensors depending on how to obtain depth information. In this paper, we take a look at several ways of depth acquirement. We present not only depth acquisition methods using discussed ways, but also hybrid methods which combine both approaches to compensate for drawbacks of each approach. Furthermore, we introduce several matching cost functions and post-processing techniques to enhance the temporal consistency and reduce flickering artifacts and discomforts of users caused by inaccurate depth estimation in 3D video.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.11 no.2
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• pp.160-168
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• 2008

Purpose: This study was designed to characterize the nutritional status and assess obesity to determine the relationship between obesity and serum lipid profiles in 6~7 year old children. Methods: In 2007, we surveyed 483 children (233 boys and 250 girls) aged 6~7 years. The total cholesterol, triglyceride levels and HDL-cholesterol were measured in the fasting state. Dietary information was obtained by a questionnaire. Results: The prevalence of obesity was 9.9%. There was no significant difference between genders. The mean caloric intake was 1,781 kcal in boys and 1,640 kcal in girls. The prevalence of excessive calories was 33% in boys and 30% in girls. The prevalence of a total cholesterol ${\geq}$200 mg/dL was 8.4%, TG ${\geq}$130 mg/dL was 5.0%, LDL-cholesterol ${\geq}$130 mg/dL was 3.1%, and HDL-cholesterol <35 mg/dL was 4.4%. The prevalence of hypertension was 2.1%. There was no significant difference between genders. The systolic blood pressure, triglyceride levels and LDL-cholesterol were significantly related to an increased obesity index (p<0.05). The mean caloric intake and nutritive component were not related to the obesity index. The obesity group was compared to the control group: for triglycerides ${\geq}$130 mg/dL the odds ratio was 4.08; for LDL-cholesterol ${\geq}$130 mg the odds ratio was 2.85; for a TC/HDL-cholesterol ${\geq}$4.0 the odds ratio was 1.16. The BMI and triglyceride levels in the group with hypertension were higher than control group (p<0.05). There were significant positive correlations between the BMI and blood pressure as well as the LDL-cholesterol and triglycerides (p<0.05). The BMI was not correlated with the mean caloric intake or nutrition. Conclusion: The prevalence of hypertension and hyperlipidemia in 6~7 year old children was significantly related to an increased obesity index. The management of obesity in 6~7 year old children should include a reduction in the risk for hyperlipidemia and hypertension.

• Journal of Broadcast Engineering
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• v.19 no.4
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• pp.478-490
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• 2014

In order to make 3-D display technique a better tool to provide viewers with realistic stereoscopic experience, various researches have been done in the many relevant fields. This psychophysical study was designed to investigate whether there was any difference in the perceptual processing between a dominant and non-dominant eye when a 3-D cue was provided exclusively to only one eye. We measured the reaction time for detecting a depth change by providing the viewer's each eyes with differential 3-D stimuli, which have systematical patterns. We obtained that there was a consistent 3-D perceptual performance when the 3-D cue was provided to the viewers' left eye regardless of their eye dominance. The result suggests that it might be a better technique to arrange the camera for left eye to carry 3-D cues to get the viewer's consistent 3-D perception.

• Proceedings of the Optical Society of Korea Conference
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• 2000.02a
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• pp.90-91
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• 2000

광섬유는 수십THz이상의 넓은 대역폭과 0.2-0.4 dB/Km의 적은 전송손실의 우수성을 가지고 있으므로 이를 CDMA시스템에 적용하면 고속, 대용량의 데이터 전송 및 비동기식 전송의 장점이 있으므로 광 LAN이나 광 교환기 등의 광통신 네트워크에 유용하게 사용할 수 있다$^{[1][2]}$ . 그러나 광CDMA시스템은 다수 사용자가 동시에 데이터를 전송할 때 다른 사용자의 데이터 전송으로부터 발생되는 오류정보를 최소화하기 위해 최적의 자기상관 및 상호상관특성을 가져야 자신의 정보데이터를 복원할 수 있다$^{[3]}$ . 따라서 본 논문에서는 광섬유 지연선을 이용한 광 CDMA시스템에서 코드구성을 광 직교 코드로 하였을 경우 컴퓨터 시뮬레이션을 통한 시스템 해석에 대하여 서술한다. 컴퓨터 시뮬레이션을 통해 광 직교 코드를 사용한 경우 사용자수가 증가함에 따른 최적의 자기상관 및 상호상관특성을 갖는 코드를 구하고, 임계값 변화에 따른 에러확률을 분석한다. (중략)

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2009.04a
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• pp.348-351
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• 2009

본 논문에서는 구조해석을 위한 PSC 박스 거더교의 객체 정보 모델에 관한 연구를 수행하였다. 대상 교량의 객체 정보 모델을 생성하기 위해서는 수많은 형상 및 치수에 관한 파라미터를 필요로 하게 된다. 따라서 본 연구에서는 이 교량의 설계 목적에 맞는 파라미터를 분류하였고, 파라미터들 사이의 계층구조(Structure)와 상관관계를 정의하였다. 또한 본 연구에서 적용된 인터페이스 프로그램은 3차원 객체 모델에서 출력된 파라미터를 변환하여 구조해석을 위한 입력값으로 변환시켜, 해석 결과값을 구조계산서에 출력시킴으로써 엔지니어가 설계 타당성과 모델변경 요구를 용이하게 할 수 있게 하였다. 그리고 대상 모델에 대한 설계변경은 구조물의 특징에 맞는 상관파라메트릭 방법을 적용하여 신속하게 할 수 있도록 유도하였다. 이 연구를 통해 건설구조물의 설계를 3D 모델로 하기위한 가능성을 확인하였다.

• Cartoon and Animation Studies
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• s.19
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• pp.161-181
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• 2010

Human beings experience the outside world through senses and have developed various ways of representation to preserve what they've experienced. The rapid progress of digital technology has opened a new era of representation technology, and furthermore, is functioning as a technology which offers new experiences. The sensory experiences through the sense of sight, which humans depend on more than 70% to perceive the outside world, have been becoming the center of representing the reality as the 3-D graphics technology has been growing, and developing by being grafted onto different areas of study. Various technologies to express the sense of reality, such as the technology to reinforce the virtual reality and to represent it in the reality, computer graphic, TUI technology, and five sensory technologies which apply humans' senses, are making advancement based on humans' visual features and sensory elements. In particular, the 3-D technology to display solidness provides not only representation but also new sensory experiences, and is emerging as the key technology to image contents. However, compared to the development of technology of 3-D graphics, there have been few basic studies on the principles of the sense of vision. Therefore, in this study, the principles and elements to sense videos will be examined. The sensory features of 3-D images to represent the sense of reality will be researched into, especially focusing on the experiential and physiological elements to sense 3-D structures, and the physical and psychological elements to sense shapes, which might be hopefully the basic study for producing 3-D contents.

• Proceedings of the Korean Information Science Society Conference
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• 2001.10b
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• pp.454-456
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• 2001

본 논문에서는 비디오 영상열 내에 컴퓨터가 생성한 가상의 3D 영상을 이음새 없이 추가하기 위한 문제에 초점을 맞추고 있다. 2단계의 견고한 통계적인 메소드는 추적된 커브들의 모델-영상 대응점으로부터 보다 정확한 자세를 평가하기 위하여 자세 계산을 위해 사용되었다. 또한, 관점의 정확성 향상을 위하여 두 개의 연속하는 영상들간에 매치될 수 있는 핵심점을 카메라 움직임에 대한 상관관계 함수로 사용하여 매칭 에러와 reprojection 에러를 포함한 비용함수를 최소화함에 의해 관점을 향상시킨다. 비디오 영상내 객체 영상과 가상의 3D 영상간에 발생하는 폐색 공간문제를 해결하기 위하여 반 자동 알고리즘을 제안하였다.

• Journal of Nutrition and Health
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• v.52 no.5
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• pp.465-474
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• 2019

Purpose: This study examined the association between the serum 25-hydroxyvitamin D concentration and the cognitive functions in Korean elderly. Methods: The subjects were 393 adults aged 60 years or older who participated in the Yangpyeong cohort between July 2009 and August 2010. The subjects were classified into deficiency, insufficiency, or adequacy groups according to the serum 25-hydroxyvitamin D concentration diagnostic criteria suggested by the US Institute of Medicine (IOM). The cognitive function was assessed based on the Korean version of the Mini-Mental State Examination (MMSE-KC). The dietary intake was assessed using the quantitative food frequency questionnaire with 106 food items. Results: The proportions of deficiency, insufficiency, or adequacy in serum 25-hydroxyvitamin D were 6.6%, 44.5%, and 48.9%, respectively. The serum 25-hydroxyvitamin D concentration was significantly higher in men than in women and in outdoor workers than in other occupations. The adequacy group had higher MMSE-KC scores than the other two groups, but not to a significant degree. The proportion of cognitive impairment tended to decrease with increasing serum vitamin D concentration to deficiency, insufficiency, and adequacy (p for trend = 0.029). The deficiency group had a 2.28 times higher risk of cognitive impairment than the adequacy group, but the difference was not statistically significant (OR, 2.28; 95% CI, 0.18 ~ 1.07, p for trend = 0.119). Conclusion: The serum vitamin D concentration tended to be associated with the cognitive function in elderly Koreans living in rural areas. To confirm the associations, further longitudinal studies with large samples were required.

• Journal of the Korean Society of Radiology
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• v.14 no.1
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• pp.61-68
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• 2020

The purpose of this study is to investigate the correlation of blooming artifacts according to dilution ratio of contrast agent on CT angiography images. A total of 10 sets were prepared by differently setting the ratio of contrast media and saline in a ball phantom made by a 3D printer. CT scan images were obtained and reconstructed by MIP and MPR techniques to obtain axial, sagittal and coronal images, respectively. After, the diameter of the ball phantom of the image obtained after the test was measured each 30 times, a total 1800 times. As a result, the dilution of 20:80 in the coronal plane was the smallest (p<0.05). Similarly, when dilute to 20:80 in the sagittal plane of MIP, it was the smallest as 20.39 ± 0.08 mm (p<0.05). Correlation analysis between dilution ratio and measurement size confirmed strong negative correlations in all reconstructed images (p<0.05). In conclusion, the higher the dilution ratio of the contrast agent, the more difficult it is to measure actual blood vessel measurement. Therefore, this study may provide basic data in future studies on actual measurement.