• Composites Research
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• v.29 no.1
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• pp.1-6
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• 2016

Low-speed impact was localized on a stiffened composite structure, using 4 FBG sensors with 100 kHz-sampling rate interrogator and devised localization algorithm. The composite specimen consists of a main spar and several stringers, and the overall size of the specimen's surface is about $0.8{\times}1.2m$. Pre-stored reference data for 247 grid locations and 36 stiffener locations are gathered and used as comparison target for a random impact signal. The proposed algorithm uses the normalized cross-correlation method to compare the similarities of the two signals; the correlation results for each sensor's signal are multiplied by others, enabling mutual compensation. 20 verification points were successfully localized with a maximum error of 43.4 mm and an average error of 17.0 mm. For the same experimental setup, the performance of the proposed method is evaluated by reducing the number of sensors. It is revealed that the mutual compensation between the sensors is most effective in the case of a two sensor combination. For the sensor combination of FBG #1 and #2, the maximum localization error was 42.5 mm, with average error of 17.4 mm.

• Journal of Nutrition and Health
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• v.50 no.5
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• pp.437-446
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• 2017

Purpose: This meta-analysis aimed to evaluate the effect of cassia cinnamon (Cinnamomum. cassia and C. aromaticum) on the glycemic response with a focus on the preparation of dehydrated powder and water extract. Methods: We searched Pubmed, Cochrane, EMBASE, Science Direct, and the Korean Studies Information Service System (KISS) through May 2017. In the meta-analysis for the preparation of powder, eight trials reporting fasting blood glucose (FBG), four trials reporting HbA1c, and three trials reporting the postprandial glycemic response were included. For the water extract, six trials reporting FBG and four trials reporting HbA1c were eligible for this study. A random-effects model was used to calculate the pooled effect size. Results: Cassia cinnamon powder intake significantly lowered FBG by -1.55 mmol/L (95% CI, -2.45, -0.64; p = 0.001) and the AUC of postprandial blood glucose level by $-51.8mmol/L{\cdot}min$ (95% CI, -85.5, -18.1; p = 0.003). There was a significant difference in FBG between water extract of cinnamon and placebo of -0.76 mmol/L (95% CI, -1.09, -0.43; p = 0.000). However, blood HbA1c level was not significantly altered by any preparation of cinnamon. No statistical heterogeneity was observed for any analysis except in the case of FBG for cinnamon powder. Results of funnel plots and Egger's regression suggest a low likelihood of publication bias in all biomarkers (p > 0.05). Conclusion: According to this meta-analysis, there was possible evidence to support a relationship between cassia cinnamon intake and fasting glucose in both preparation of powder and water extract. Furthermore, new evidence of the health benefits on postprandial glucose regulation of cinnamon powder was obtained.

• Journal of the Korean Applied Science and Technology
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• v.35 no.4
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• pp.1145-1155
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• 2018

The purpose of this study was to investigate the effect of dietary restriction(DG), aerobic exercise(EG), dietary restriction with aerobic exercise(DEG) on weight, improvement of obesity, blood lipid profiles and metabolic risk factors of obese female college students. Experiments was conducted 5 times a week for 8 weeks. DG spent 300kcal/day, and EG used 300kcal/day to run, DEG each consumed 150kcal/day limits. As s result, in case of body composition, weight(p<.011) and BMI(p<.008) were decreased in DG group, and weight(p<.044, p<.017), body fat(p<.047, p<.018), BMI(p<.03, p<.008), body fat%(p<.036, p<.015) and WHR(p<.049, p<.027) were decreased in EG and DEG groups. In case of blood lipid profiles's change, there are some differences on TC(p<.006), TG(p<.047) according to the time. In DG:HDL-C(p<.028), in EG:TG(p<.038), in DEG:TC(p<.014), LDL-C(p<.007) have decreased. In case of metabolic risk factor's change, there are some differences on FBG(p<.001), insulin(p<.004), HOMA-IR(p<.001), leptin(p<.000), adiponectin(p<.038), resistin(p<.010) according to time. In DG:HOMA-IR(p<.035) and leptin(p<.007), EG:FBG(p<.043) and leptin(p<.003), DEG:FBG(p<.014), insulin(p<.005), HOMA-IR(p<.005), leptin(p<.016), and resistin(p<.040) have decreased. In conclusion, combined treatment of eating restriction with aerobic exercise was the most effective way to improvement of weight, blood lipid profiles and metabolic risk factors in obese female college students rather than respectively alone treatment.

• Disaster Prevention Review
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• v.13 no.4
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• pp.162-163
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• 2011

• Journal of Korean Association for Spatial Structures
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• v.10 no.3
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• pp.5-9
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• 2010

• Optical Science and Technology
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• v.17 no.1
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• pp.43-47
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• 2013

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2005.04a
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• pp.440-447
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• 2005

In this study, strain measurement and its applicability to estimated deflection curve using fiber bragg grating sensors was conducted. For this purpose, reinforced concrete beams were made and sensors were attached both on the surface of the beams and inside steel. Two types of sensors were used to detect strain on the beams and steel : fiber bragg grating sensors, electric resistance strain sensors. So fatigue test is done with measuring strain of specimen. In addition, this experiments estimates the optimum deflection curve that converts strain curve data measured by FBG sensors into deflection.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.635-638
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• 2005

In this paper, we present thermal characteristics of a fiber Bragg grating(FBG) filter, including peak reflectivity, FWHM bandwidth, and wavelength shift by various refractive index change. The reflection spectrum of a FBG filter with refractive index change is affected by its thermal stability.

• Proceedings of the Optical Society of Korea Conference
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• 2009.02a
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• pp.297-298
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• 2009

파장 분할 방식의 광섬유 격자 센서의 멀티플렉싱 능력을 향상시키기 위하여 이중 격자의 파장 간격 변조로 구분되는 다중 광섬유 격자 센서 시스템을 제안하였으며, 서로 다른 파장 간격을 가지는 센서의 상태와 위치를 정확히 구별할 수 있는 방법을 연구하고 씨뮬레이션을 통하여 확인하였다. 또한 변형력 하에서 광섬유격자 센서들간의 스펙트럼 중첩으로 불명확한 브래그 피크를 최급 강하법(steepest descent method) 알고리즘을 사용하여 약 3 pm이내의 표준편차로 결정할 수 있었다.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.811-816
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• 2004

The tactile force sensor was studied using Fiber Bragg Grating (FBG). The FBG is able to multiplex easily and is immune to electromagnetic environment. A sensor frame was designed to a cantilever beam type. Strain of a beam is related with the peak shift of a bragg wavelength. Finite Element Method (FEM) was used for getting an appropriate thickness from 0.2 mm to 0.3 mm thick. FEM results showed that 0.3 mm thick was suitable for the force range 10 N. The force resolutions of 0.039 N and 0.113 N were obtained with optical spectrum analyser and tunable Fabry-Perot filter, respectively.