• Nutrition Research and Practice
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• 제13권6호
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• pp.509-520
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• 2019

BACKGROUND/OBJECTIVES: This study evaluated whether a mobile health (mHealth) application can instigate healthy behavioral changes and improvements in metabolic disorders in individuals with metabolic abnormalities. SUBJECTS/METHODS: Participants were divided into an mHealth intervention group (IG), which used a mobile app for 24 weeks, and a conventional IG. All mobile apps featured activity monitors, with blood pressure and glucose monitors, and body-composition measuring devices. The two groups were compared after 24 weeks in terms of health-behavior practice rate and changes in the proportion of people with health risks, and health behaviors performed by the IG that contributed to reductions in more than one health risk factor were analyzed using multiple logistic regression. RESULTS: Preference for low-sodium diet, reading nutritional facts, having breakfast, and performing moderate physical activity significantly increased in the mHealth IG. Furthermore, the mHealth IG showed a significant increase of eight items in the mini-dietary assessment; particularly, the items "I eat at least two types of vegetables of various colors at every meal" and "I consume dairies, such as milk, yogurt, and cheese, every day." The proportion of people with health risks, with the exception of fasting glucose, significantly decreased in the mHealth IG, while only the proportion of people with at-risk triglycerides and waist circumference of females significantly decreased in the control group. Finally, compared to those who did not show improvements of health risks, those who showed improvements of health risks in the mHealth IG had an odds ratio of 1.61 for moderate to vigorous physical activity, 1.65 for "I do not add more salt or soy sauce in my food," and 1.77 for "I remove fat in my meat before eating." CONCLUSIONS: The findings suggest that the additional use of a community-based mHealth service through a mobile application is effective for improving health behaviors and lowering metabolic risks in Koreans.

• 인터넷정보학회논문지
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• 제19권1호
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• pp.105-111
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• 2018

건축 구조물의 상대적인 변위 계측을 위하여 2메가 픽셀 Full HD(FHD) 해상도의 카메라와 디지털 영상상관(DIC, Digital Image Correlation) 플랫폼을 설계하고, 계측에 영향을 주는 영상 품질을 분석하였다. DIC 플랫폼은 Freescale사의 I.MX6를 기반으로 설계하였다. 영상 상관을 이용한 계측은 영상의 품질에 따라 계측 정밀도에 영향을 줄 수 있는데, 이러한 영상 품질 요인으로 영상의 밝기(brightness), 대조(contrast), 신호대 잡음비(SNR, Signal to Noise Ratio)를 분석하였다. 관심 영역(ROI, Region Of Interest)으로 설정한 부분에서 추출한 영상을 기준 영상으로 삼고, 일정 시간 경과 후 디지털 영상 상관(DIC)을 이용하여 기준 영상의 이동을 화소 및 부화소 단위로 추적 계산하여 변위를 측정하였다. 더불어 DIC 기반의 비접촉 원격 계측의 유효성을 파악하기 위하여 25m, 35m, 50m의 계측 거리에서, 영상 품질 요인 및 ROI 의 크기를 조정하여 측정을 하고 정밀도를 분석하였다.

• 대한전자공학회논문지SD
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• 제43권6호
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• pp.9-17
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• 2006

SoC(System-On-Chip) 시스템에서 초 저전력 시스템을 구현하기 위한 dynamic voltage and frequency scaling (DVFS)알고리즘에 사용될 시스템 버스의 다중 코어 전압 레벨을 생성해주는 새로운 다계층(multi-level) 코어 전압용 high-speed level up/down Shifter 회로를 제안한다. 이 회로는 내부 회로군과 외부 회로군 사이에서 서로 다른 전압레벨을 조정 접속하는 I/O용 level up/down shifter interface 회로로도 동시에 사용된다. 제안하는 회로는 인터페이스 접속에서 불가피하게 발생하는 속도감쇄와 Duty Ratio 불안정 문제를 최소화하는 장점을 갖고 있다. 본 회로는 500MHz의 입력 주파수에서 $0.6V\sim1.6V$의 다중 코어 전압을 각 IP들에서 사용되는 전압레벨로, 또는 그 반대의 동작으로 서로 Up/Down 하도록 설계하였다 그리고 제안하는 I/O 용 회로의 level up shifter는 500MHz의 입력 주파수에서 내부 코어 용 level up shifter의 출력전압인 1.6V를 I/O 전압인 1.8V, 2.5V, 3.3V로 전압레벨을 상승 하도록 설계하였으며, level down shifter는 반대의 동작으로 1Ghz의 입력 주파수에서 동작하도록 설계하였다. 시뮬레이션 및 결과는 $0.35{\mu}m$ CMOS Process, $0.13{\mu}m$ IBM CMOS Process 와 65nm CMOS model 변수를 이용한 Hspice를 통하여 검증하였다. 또한, 제안하는 회로의 지연시간 및 파워소모 분석과 동작 주파수에 비례한 출력 전압의 Duty ratio 왜곡에 대한 연구도 하였다.

• Communications for Statistical Applications and Methods
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• 제11권3호
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• pp.475-484
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• 2004

This paper consider the testing problem of grouped heteroscedasticity in the linear regression model. We provide the Lagrange Multiplier(LM), Wald, Likelihood Ratio (LR) test statistis for testing of grouped heteroscedasticity. Monte Carlo experiments are conducted to study the performance of these tests.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2007년도 춘계학술대회 논문집
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• pp.127-130
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• 2007

Effect of the forging process parameters on the void crushing is the cogging process has been studied in order to find the most effective factor. The Process parameters used for this study are die width ratio, reduction ratio and pre-cooling time before cogging process. Void crushing analysis about the selected process parameters was carried out using FE analysis. The results of FE analysis were evaluated by Taguchi method. It was found that the efficiency of void crushing increases with an increase in the values of all selected process parameters and the principal factor controlling the void crushing was identified as the reduction ratio.

• 한국세라믹학회지
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• 제42권1호
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• pp.16-21
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• 2005

The effect of additive composition, using AlN and $Er_{2}O_{3}$ as sintering additives, on the mechanical properties of liquid-phase-sintered, and subsequently annealed SiC ceramics was investigated. The microstructures developed were quantitatively analyzed by image analysis. The average thickness of SiC grains increased with increasing the $Er_{2}O_{3}/(AlN + Er_{2}O_{3})$ ratio in the additives whereas the aspect ratio decreased with increasing the ratio. The mechanical properties versus $Er_{2}O_{3}/(AlN + Er_{2}O_{3})$ ratio curve had a maximum; i.e., there was a small composition range at which optimum mechanical properties were realized. The best results were obtained when the ratio ranged from 0.4 to 0.6. The flexural strength and fracture toughness of the SiC ceramics were $550\~650\;MPa$ and $5.5\~6.5$ MPa${\cdot}m^{1/2}$, respectively.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 춘계 학술발표회 논문집(II)
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• pp.389-392
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• 2006

In this study, I examined hardening and non-hardening of the DFRCC (Ductile Fiber Reinforced Cementitious Composites) according to sand-aggregate ratio and the diameter of PVA fiber to develope PVA fiber reinforced concrete with the feature of DFRCC. As a result of this study, the fresh properties of DFRC is similar regardless of sand-aggregate ratio. The bending stress of DFRC also increased as the sand-aggregate ratio increased. And the bending stress-displacement was the most stable when the PVA $100{\mu}m$ was used regardless of sand-aggregate ratio.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2008년도 춘계학술대회 논문집
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• pp.75-78
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• 2008

The predictive equation of void-closure was developed to evaluate void crush ratio with respect to the process variables in the cogging process of a large round bar. The comprehensive finite element analysis with the process variables such as reduction ratio and die width ratio was carried out. The predictive equation of void-closure for cogging process was established on the basis of the regression analysis with the extensive FE analysis results and verified by comparing the predicted results with FEA results with various forging passes.

• 공업화학
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• 제8권2호
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• pp.161-171
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• 1997

인쇄회로기판의 식각폐수를 전기화학적 방법을 이용하여 양극에서 이를 재생하고, 음극에서 구리를 석출하기 위한 실험을 행하였다. 양극에서의 Cu(I)의 산화에 따른 Cu(I)/Cu(II) 변화는 Pt와 Ag/AgCl/4M KCl 전극사이의 전위차를 이용하여 측정하였으며, 반응의 진행에 따른 양극에서의 염소기체 발생은 용액내에 Cu(I)의 농도를 일정치 이상으로 유지시키고, 비다공성 흑연전극을 이용하여 억제할 수 있었다. 그리고, 음극에서의 구리석출은 전류밀도 $360mA/cm^2$, 구리이온농도 12g/l 일때 가장 효율적이며 석출된 구리는 dendrite구조임을 알 수 있었다. 또한 석출효율과 회수방법을 고려할 때 음극으로서 Ti전극을 사용할 경우 가장 우수한 효율을 얻을 수 있었다. 전해온도가 증가함에 따라서 전류효율은 낮아졌으며, 전력효율은 $50^{\circ}C$에서 최대값을 나타내었다.

• Restorative Dentistry and Endodontics
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• 제43권4호
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• pp.46.1-46.10
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• 2018

Objectives: This study was to evaluate the antibacterial effect of different instrumentation and irrigation techniques using confocal laser scanning microscopy (CLSM) after root canal inoculation with Enterococcus faecalis (E. faecalis). Materials and Methods: Mesiobuccal and mesiolingual canals of extracted mandibular molars were apically enlarged up to a size 25 hand K-file, then autoclaved and inoculated with E. faecalis. The samples were randomly divided into 4 main groups according to the system of instrumentation and irrigation: an XP-endo Shaper (XPS) combined with conventional irrigation (XPS/C) or an XP-endo Finisher (XPF) (XPS/XPF), and iRaCe combined with conventional irrigation (iRaCe/C) or combined with an XPF (iRaCe/XPF). A middle-third sample was taken from each group, and then the bacterial reduction was evaluated using CLSM at a depth of $50{\mu}m$ inside the dentinal tubules. The ratio of red fluorescence (dead cells) to green-and-red fluorescence (live and dead cells) represented the percentage of bacterial reduction. The data were then statistically analyzed using the Kruskal-Wallis test for comparisons across the groups and the Dunn test was used for pairwise comparisons. Results: The instrumentation and irrigation techniques had a significant effect on bacterial reduction (p < 0.05). The iRaCe/XPF group showed the strongest effect, followed by the XPS/XPF and XPS/C group, while the iRaCe/C group had the weakest effect. Conclusions: Combining iRaCe with XPF improved its bacterial reduction effect, while combining XPS with XPF did not yield a significant improvement in its ability to reduce bacteria at a depth of $50{\mu}m$ in the dentinal tubules.