• Journal of Nutrition and Health
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• v.47 no.4
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• pp.287-299
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• 2014

Purpose: The goal of this study was to examine body image satisfaction and perception according to weight status, and to investigate those associations with dietary habits and nutritional status among preadolescent children. Methods: Body image and dietary habits and intake were assessed in 134 elementary school students in grade 4. Children were categorized according to normal and overweight or obese groups. Figure rating scales were used to assess body image perception (identification of perceived current body size) and dissatisfaction (difference between perceived current body size and ideal body image). Results: There were sex differences in body image perceptions. Normal-weight girls, overweight or obese girls and boys were more likely to desire a leaner body size than their perceived body size compared with normal-weight boys. Body image satisfaction and perception showed an association with weight status. More overweight or obese children indicated dissatisfaction or underestimation of body image than normal-weight children. Children with body image dissatisfaction due to heavier perceived body size than ideal body image showed lower frequencies of consumption of meals and vegetables, compared to those who were satisfied with their body image. Children who underestimated their body image were more likely to have a lower frequency of breakfast and meal regularity and a higher frequency of eating out of home or food deliveries than those with accurate body image perception. In addition, body image underestimation showed an association with lower intakes of protein, dietary fiber and calcium, and the higher percentage of calories derived from fat. Conclusion: Body image dissatisfaction as well as underestimation in children before puberty showed an association with overweight or obesity, and was also related to unhealthy dietary habits. These findings highlight the importance of accurate perception and satisfaction with body image in preadolescent children in order to prevent development of obesity in adolescents and adults.

• 한국해양학회지
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• v.21 no.2
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• pp.73-84
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• 1986

Photometric Winkler titration provides high precision enough to use the oxygen method in moderately productive waters In short incubation (2-4hr), about $2{\mu\textrm{g}}C/\ell/h$ can be differentiated by the photometric titration. The oxygen and $^{14}C$ methods resulted in good agreement with each other in the diurnal primary production measurements. Despite small descrepancies the severe underestimation of $^{14}C-technique$ was not observed in short-term incubation. Size-fractionated production studies indicated the importance of nanoplanktonic production in the coastal water (62-88%). Bacterial respiration may lead to significant underestimation in estimating net photosynthesis in the oxygen method. In spite of some problems associated with the ecological application of antibiotics, it seems feasible to use Gentamycin in separating planktonic respiration from that of total community.

• Journal of the Korean Society of Propulsion Engineers
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• v.16 no.6
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• pp.32-40
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• 2012

For predicting eigenfrequency and initial growth rate of combustion instabilities in lean premixed gas turbine combustor, linear thermoacoustic analysis model was developed in the current paper. A model combustor was selected for the model validation, which has well-defined inlet and outlet conditions and a relatively simple geometry, compared to the combustor in the previous works. Analytical linear equations for thermoacoustic waves were derived for a given combustion system. It was found that the prediction results showed a good agreement with the measurements, even though there was underestimation for instability frequencies. This underestimation was more obvious for a longer flame (i.e. wider temperature distribution) than for a shorter flame.

• Journal of Korea Water Resources Association
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• v.36 no.2
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• pp.237-249
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• 2003

Wind effects on a rain gauge can cause a significant underestimation of rainfall depths and contribute to the inconsistency in rainfall data. To revise the rainfall data requires the study about calculation of deficiency percentages of rain catch. There are few studies which reflect the variation of wind speed. in this study, the raindrop terminal velocity is quantified according to the particle size of rainfall. The model for calculating deficiency percentages of rain catch according to the particle size of rainfall is examined by experimentation. Experimentation shows that deficiency percentages of rain catch have no relationship with rainfall intensity and affected by raindrop diameter. In conclusion, the estimated deficiency percentages of rain catch coincided with the experimental results and can be used as recommended adjustment factors.

• The Journal of the Korea Contents Association
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• v.16 no.11
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• pp.240-252
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• 2016

The purposes of this paper examines the extant to which congruence in leader and follower rating of LMX quality is related to organizational commitment, and perceptions of organizational politics(POPs). A conceptual model is introduced that identifies four combinations of leader and follower LMX ratings of Cogliser et al.(2009): balanced/low LMX(low leader and follower LMX), balanced/high LMX(high leader and follower LMX), follower overestimation(low leader LMX/high follower LMX), follower underestimation(high leader LMX/low follower LMX). The summary of results based on a sample of 236 matched pairs of leaders and followers in KOREA is as follows: First, balanced/high LMX and follower overestimation were associated with relatively high levels of affective organizational commitment, and perceptions of organizational politics. However, follower underestimation and balanced/low LMX was related to low levels of follower outcomes. In particular, follower underestimation and balanced/low LMX were significantly different from balanced/high LMX and follower overestimation. Second, perceptions of organizational politics was negatively related to affective organizational commitment in the four LMX relationship types. Especially, the negative relationship between POPs and organizational commitment was stronger for people who are low as compared with high in LMX quality. Theoretical and practical implications of our findings as well as directions for future research are provided.

• Korean Journal of Remote Sensing
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• v.38 no.6_1
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• pp.1301-1314
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• 2022

Normalized Difference Vegetation Index (NDVI) is utilized as an indicator to represent the vegetation condition on the land surface in various applications such as land cover, crop yield, agricultural drought, soil moisture, and forest disaster. However, satellite optical sensors for visible and infrared rays cannot see through the clouds, so the NDVI of the cloud pixel is not a valid value for the land surface. This study proposed a real-time correction of the underestimation noise for GEO-KOMPSAT-2A (GK2A) daily NDVI and made sure its feasibility through the quantitative comparisons with Moderate Resolution Imaging Spectroradiometer (MODIS) NDVI and the qualitative interpretation of time-series changes. The underestimation noise was effectively corrected by the procedures such as the time-series correction considering vegetation phenology, the outlier removal using long-term climatology, and the gap filling using rigorous statistical methods. The correlation with MODIS NDVI was higher, and the difference was lower, showing a 32.7% improvement compared to the original NDVI product. The proposed method has an extensibility for use in other satellite products with some modification.

• Journal of the Korean Data and Information Science Society
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• v.20 no.5
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• pp.895-903
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• 2009

The penalized partial likelihood based on restricted maximum likelihood method has been widely used for the inference of frailty models. However, the standard-error estimate for frailty parameter estimator can be downwardly biased. In this paper we show that such underestimation can be corrected by using hierarchical likelihood. In particular, the hierarchical likelihood gives a statistically efficient procedure for various random-effect models including frailty models. The proposed method is illustrated via a numerical example and simulation study. The simulation results demonstrate that the corrected standard-error estimate largely improves such bias.

• Journal of the Korean Data and Information Science Society
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• v.17 no.3
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• pp.999-1007
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• 2006

The semiparametric gamma frailty models have been often used for multivariate survival analysis because they give an explicit marginal likelihood. The commonly used estimation procedure is the profile likelihood method based on marginal likelihood, which provides the same parameter estimates as the EM algorithm. In this paper we show in finite samples the standard profile-likelihood method can lead to an underestimation of parameters, particularly for the frailty parameter. To overcome this problem, we propose an adjusted profile-likelihood method. For the illustration a numerical example and a small-sample simulation study are presented.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.20 no.2
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• pp.71-77
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• 2015

High-Performance Liquid Chromatography (HPLC) is a widely used method for measuring the concentration of chlorophyll a as an indicator for estimating phytoplankton biomass and primary production and also for identifying carotenoids to determine phytoplankton composition. However, tissue grinding procedure requires a lot of time and experience in the analysis of multiple sample. Accordingly, we measured the concentrations of photosynthetic pigments before and after the grinding, in order to understand the grinding effects on the quantitative analysis of chlorophylls and carotenoids using samples from southwestern East Sea. When tissue grinding procedure was omitted, we found that Chl a concentrations were underestimated up to 45% in average. Also, concentrations of Zeaxanthin, 19'-butanoyloxyfucoxanthin, 19'-hexanoyloxyfucoxanthin, biomarkers of pico and nano-size phytoplankton, were underestimated up to maximum 77~85% without grinding. We found that the smaller the phytoplankton, the bigger underestimation of their biomarker pigments concentration is likely to happen due to the incomplete extraction. Thus, tissue grinding procedure should be included for HPLC analysis in all cases, to prevent the underestimation of not only Chl a but also carotenoids pigments.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.36C no.3
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• pp.26-34
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• 1999

A new silicon-based IC interconnect transmission line parameter extraction methodology is presented and experimentally examined. Unlike the PCB or MCM interconnects, a dominant energy propagation mode in the silicon-based IC interconnects is not quasi-TEM but slow wave mode(SWM). The transmission line parameters are extracted taking the silicon substrate effect (i.e., slow wave mode) into account. The capacitances are calculated considering silicon substrate surface as a ground. Whereas the inductances are calculated by using an effective dielectric constant. In order to verify the proposed method, test patterns were designed. Experimental data have agreement within 10%. Further, crosstalk noise simulation shows excellent agreements with the measurements which are performed with high-speed time domain measurement ( i.e., TDR/TDT measurements) for test pattern, while RC model or RLC model without silicon substrate effect show about 20~25% underestimation error.