• Korean Journal of Ecology and Environment
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• v.33 no.2 s.90
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• pp.69-79
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• 2000

Fractal geometry has become one of prospective research approaches as the complex structure of natural entities is not easily characterized by traditional Euclidean geometry. With the fractal geometry, we can better decipher the complex structure and identify natural and anthropogenic agents of landscape patterns occurring at different spatial scales. The usefulness of fractal, however, has not been fully appreciated among Korean academic societies, especially in ecological and limnological fields. We attempt to address three points in this study. First, we introduce the concept and dimension of fractal and review relevant research approaches, especially with respect to ecological and limnological phenomena. Second, we explore possible applications of fractal to some aspects of geography and land use characteristics in South Korea. For the analyses of fractal dimensions, we used data published in other studies previously and collected for this study. Data were analyzed by a perimeter/area method of fractal dimension for the spatial distribution of global solar radiation and leaf area index, and the movement of wild boars in forested landscapes of mid-eastern Korea. The same approach was also applied to the water channel of a hypothetical river and the shape of reservoirs in Yongin, Kyunggi Province. Finally, we discuss the results and key issues to consider when a fractal approach is employed in ecology and limnology.

• Korean Journal of Community Nutrition
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• v.12 no.3
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• pp.247-258
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• 2007

This study was conducted to investigate weight control status and associated factors among health-related major female college students. The subjects consisted of 41 nutrition and 78 physical exercise major female college students. Nutrient intakes, biochemical index, nutrition knowledge (recognition and accuracy), interest of weight control, body satisfaction, self-recognition of health condition, self-evaluated body weight were studied. About 73% of nutrition and 79% of physical exercise major female students were in the normal range of BMI ($18.5{\sim}23$) and 2% of nutrition and 1% of physical exercise major female students were underweight, 10% of nutrition and 6% of physical exercise major female students were obese. There were no significant differences in height and weight by major but %body fat and WHR in physical exercise majors were significantly lower than nutrition major students (respectively p<0.01, p<0.05). Overall, nutrition intakes of subjects were not shown to be appropriate, especially Ca/P of subjects was shown $0.54{\sim}0.64$, fat% out of energy of subjects was shown $24.7{\sim}29.0$ and Na intake was shown above 2000mg. Recognition and accuracy of nutrition were higher than those of physical exercise majors (p<0.001). There were no significant differences in self-recognition of health condition, self-evaluated body weight, satisfaction of body shape by major and weight control attempt. But interest of weight control of attempter was higher than that of no-attempter in nutrition (p<0.05) and physical exercise major students (p<0.01). Significantly negative correlation was found in satisfaction of body and BMI, body fat mass, %bodyfat, WHR. And significantly positive correlation was found in interest of weight control and BMI, %bodyfat, WHR. It was noticeable to see that interest of weight control was positively correlated to accuracy and accuracy was negatively correlated to blood cholesterol level. Therefore, proper nutrition education for female college students is needed in order to improve their weight control-related health.

• Journal of Pharmacopuncture
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• v.23 no.1
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• pp.30-36
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• 2020

Objectives: The objective of the study was to prepare Bauhinia variegata loaded nanoemulsion(formulation and determine the efficacy of herbal drug formulation against diabetic peripheral neuropathic pain through acupuncture technique. Methods: Nine different ba tches of nanoemulsion (NE1 NE9) of BVN was prepared by varying the S_mix ratio and the concentration of oil. BVN was characterized to determine particle size, shape, zeta potential, polydispersity index, optical transmittance, drug release profile and stora ge stability. The optimized formulation was subjected to plantar test, behavioral tests of neuropathic pain and Von Frey filament stimulation test. Diabetes was induced by intraperitoneal injection of freshly prepared solution of Streptozotocin (60 mg/kg) to the experimental rats. Animals were made diabetic divided into four groups, Group I was untreated normal control group, Group II was diabetic control group, Group III was Bauhinia variegata extract ( treated group (100 mg/kg/day, p.o) and Group IV was BVN treated groups (100 mg/kg/day, p.o) acute and chronically. Results: The prepared B. variegata loaded nanoemulsion was nanosized (124 nm), spherical, uniform and stable over the period of 180 days with no change in physiochemical properties. The bl ood glucose and body weight of animals was normalizing after four weeks of treatment that was significant with BVN in comparison to diabetic control group. The chronic administration of BVN significantly (P<0.001) decreased hind paw withdrawal latency an d attenuated mechanical allodynia as compared with diabetic rats. Conclusion: Thus, BVN may be an effective drug formulation against diabetic peripheral neuropathic pain.

• Journal of Engineering Education Research
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• v.3 no.2
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• pp.3-13
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• 2000

The paper has analyzed and summarized about the theoretical problem occurred in the CAQC, and has developed the learning model focused on the histogram as a case study. The range of study is to systematize the basic method of histogram generally used, and to make step by step procedures under the interactive relation with the improvement of the theory that must be added in case of the calculation by the aided of MS-Excel software. A histogram is the theory to understand the population distribution from which samples are extracted, so alternative methods are presented to estimate the population shape through an experiment and a practice. In order to enlarge the application area of the histogram in the factory, the theory of normal test, the criteria of process capability index and the probability calculation of PPM are added to the histogram. The learning model of CAQC education is proposed that is consistent with the target of histogram to control and search the cause of item defectives fast and correctly.

• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.4
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• pp.111-118
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• 2010

Reinforced steel corrosion due to concrete carbonation is one of main factors on the durability of RC structure. The carbonation velocity have an effect on carbon dioxide density, concrete quality and structural shape. Specially, these problems have increased in urban area. This study investigates the carbonation status of the bridges and quantifies the effect of carbonation based on various domestic field data. The failure probability of durability is evaluated on the basis of reliability concept. According to experimental results of the carbonation depth, the carbonation depth increased with structural age and carbonation velocity decreased with high strength of concrete. In most cases, the failure probability of durability by carbonation was more than 10%. Also, The results requires the minimum cover thickness of 70-80mm for target safety index(${\beta}$=1.3) proposed by Korean concrete specification.

• Journal of the Korean Society of Propulsion Engineers
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• v.17 no.3
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• pp.47-55
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• 2013

Curved duct channel flow characteristics for non-Newtonian gel fluid is investigated. A simulant gel propellant mixed by Water, Carbopol 941 and NaOH solution has been chosen to analyze the gel propellant flow behavior. Rheological data have been measured prior to the flow analysis where water-gel propellant and water-gel propellant with $Al_2O_3$ nano particles are both used. The critical Dean number examined by the numerical simulation in the U-shape duct flow reveals that although water-gel-nano propellants have higher apparent viscosity, the critical Dean number do show no notable difference for both the two gel propellant. It is found that the power-law index may be a dominant parameter in determining the critical Dean number and that the gel with particles addition may be more vulnerable to Dean instability.

• Nuclear Engineering and Technology
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• v.44 no.4
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• pp.369-378
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• 2012

A load-following operation in APR+ nuclear plants is necessary to reduce the need to adjust the boric acid concentration and to efficiently control the control rods for flexible operation. In particular, a disproportion in the axial flux distribution, which is normally caused by a load-following operation in a reactor core, causes xenon oscillation because the absorption cross-section of xenon is extremely large and its effects in a reactor are delayed by the iodine precursor. A model predictive control (MPC) method was used to design an automatic load-following controller for the integrated thermal power level and axial shape index (ASI) control for APR+ nuclear plants. Some tracking controllers employ the current tracking command only. On the other hand, the MPC can achieve better tracking performance because it considers future commands in addition to the current tracking command. The basic concept of the MPC is to solve an optimization problem for generating finite future control inputs at the current time and to implement as the current control input only the first control input among the solutions of the finite time steps. At the next time step, the procedure to solve the optimization problem is then repeated. The support vector regression (SVR) model that is used widely for function approximation problems is used to predict the future outputs based on previous inputs and outputs. In addition, a genetic algorithm is employed to minimize the objective function of a MPC control algorithm with multiple constraints. The power level and ASI are controlled by regulating the control banks and part-strength control banks together with an automatic adjustment of the boric acid concentration. The 3-dimensional MASTER code, which models APR+ nuclear plants, is interfaced to the proposed controller to confirm the performance of the controlling reactor power level and ASI. Numerical simulations showed that the proposed controller exhibits very fast tracking responses.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.25 no.1
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• pp.81-89
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• 2012

This study propose the vibration-based damage monitoring scheme for steel girder bolt-connection member by using wireless acceleration sensor node. In order to achieve the objective, the following approaches are implemented. Firstly, wireless acceleration sensor node is described on the design of hardware components and embedded operation software. Secondly, the vibration-based damage monitoring scheme of the steel girder bolt-connection member is described. The damage monitoring scheme performed global damage occurrence alarming and damage localization estimation by the acceleration response feature analysis. The global damage alarming is applied to the correlation coefficient of power spectral density. The damage localization estimation is applied to the frequency-based damage detection technique and the mode-shape-based damage detection technique. Finally, the performance of the vibration-based damage monitoring scheme is evaluated for detecting the bolt-connection member damage on a lab-scale steel girder.

• Molecules and Cells
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• v.37 no.6
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• pp.467-472
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• 2014

Obesity is known to be strongly associated with cardiovascular disease and cancer, the leading causes of mortality worldwide, and develops owing to interactions between genes and the environment. DNA methylation can act as a downstream effector of environmental signals, and analysis of this process therefore holds substantial promise for identifying mechanisms through which genetic and environmental factors jointly contribute to disease risk. Global DNA methylation of peripheral blood cells has recently been proposed as a potential biomarker for disease risk. Repetitive element DNA methylation has been shown to be associated with prominent obesity-related chronic diseases, but little is known about its relationship with weight status. In this study, we quantified the methylation of Alu elements in the peripheral blood DNA of 244 healthy women with a range of body mass indexes (BMIs) using pyrosequencing technology. Among the study participants, certain clinical laboratory parameters, including hemoglobin, serum glutamic oxaloacetic transaminase, serum glutamic- pyruvic transaminase, total cholesterol, and triglyceride levels were found to be strongly associated with BMI. Moreover, a U-shaped association between BMI and Alu methylation was observed, with the lowest methylation levels occurring at BMIs of between 23 and $30kg/m^2$. However, there was no significant association between Alu methylation and age, smoking status, or alcohol consumption. Overall, we identified a differential influence of BMI on global DNA methylation in healthy Korean women, indicating that BMI-related changes in Alu methylation might play a complex role in the etiology and pathogenesis of obesity. Further studies are required to elucidate the mechanisms underlying this relationship.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.2
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• pp.101-105
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• 2016

The basic characteristics of glass are highly fragile and brittle consequences the ultimate purpose of glass manufacturing is to make a transparent glass with complex shape. In order to solve this problem, mechanical properties of glass can be increased by crystallization of its amorphous glass. However, glass-ceramics has become opaque through crystallization process due to the distracted interface of glass by precipitated particles. This study has been investigated thermal processing conditions of LAS transparent glass-ceramic by using DTA (differential thermal analysis), in order to control size of precipitated particle and then fabricate transparent glass-ceramic. DTA indicated that crystallization peak area was declined with increased nucleation temperature. Subsequently, we have been established optimum temperature for crystallization depending on the nucleation temperature. The transmission and thermal expansion were measured after crystallization, and the size of precipitated particle was identified in range of 20~100 nm by FE-SEM. In addition, by setting the optimized crystallization condition, with high transmission and low thermal expansion glass was synthesized through this experiment.