• The Bulletin of The Korean Astronomical Society
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• v.46 no.1
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• pp.57.2-57.2
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• 2021

Variability in Young Stellar Objects (YSOs) can be caused by time-dependent accretion rates, geometric changes in the circumstellar disks, the stochastic hydromagnetic interactions between stellar surfaces and inner disk edges, reconnections within the stellar magnetosphere, and hot/cold spots on stellar surfaces. We uncover ~1400 variables from a sample of ~5300 YSOs in nearby low-mass star-forming regions using mid-IR light curves obtained from the 5.5-years NEOWISE All Sky Survey. The mid-IR variability traces a wide range of dynamical, physical, and geometrical phenomenon. We classify six types of YSO variability based on their light curves: secular variability (Linear, Curved, Periodic) and stochastic variability (Burst, Drop, Irregular). YSOs in earlier evolutionary stages have higher fractions of variables at all types and higher amplitudes for the variability. Along with brightness variability, we also find a diverse range of secular color variations, which can be attributed to a competitive interplay between the variable accretion luminosity of the central source and the variable extinction by material associated with the accretion process. We compare the variability of known FUors/EXors and VeLLOs/LLSs, which represent two extreme ends (burst versus quiescent) of the episodic accretion process; FUors/EXors have a higher fraction of variables (65%) than VeLLOs/LLSs (41%). Short-term (few day) and long-term (decades) variability, as well as possible AGB contamination in the YSO catalogues, are also discussed.molecules become more complex by surface chemistry induced directly by high energy photons or by the thermal energy diffused over heated grain surface. Therefore, the ice composition is an

• The Bulletin of The Korean Astronomical Society
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• v.44 no.2
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• pp.64.1-64.1
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• 2019

The first high-resolution spectroscopic and new multiband photometric observations of the semi-detached Algol type binary XZ CMi were performed at the Bohyunsan Optical Astronomy Observatory (BOAO) and the Sobaeksan Optical Astronomy Observatory (SOAO), respectively. A total of 34 spectra were obtained using the 1.8 m reflector of the BOAO equipped with the Bohyunsan Optical Echelle Spectrograph to construct the radial velocity (RV) curves of the eclipsing pair. New BVRI photometric light curves were also covered by using the SOAO 61cm reflector and a CCD camera. A detailed analysis of all eclipse timings shows that the orbital period of XZ CMi has varied in an upward parabolic variation superposed on a sinusoidal oscillation with a period of 38.0 yr and a semi-amplitude of 0.0071 days. From the spectral analysis, the effective temperature and the projected rotational velocity of the primary component were determined to be T_eff,1 = 7387±161 K and v₁sini = 122±6 km s^-1, respectively. Our simultaneous synthesis of the double-lined RV and BVRI light curves gives the reliable system parameters of XZ CMi with a mass ratio (q) of 0.314, an orbital inclination (i) of 81.9 deg and a large temperature difference (∆T) of 2481 K. The individual masses and radii of both components are M₁ = 1.91±0.08M_⊙, M₂ = 0.60±0.02M_⊙, R₁ = 1.60±0.02R_⊙, R₂ = 1.13±0.02R_⊙, respectively. Although the primary component is located inside the δ Sct and γ Dor instability strips, no evidence of pulsation in the system was detected. The possible evolutionary status of XZ CMi is discussed.

• Journal of the Semiconductor & Display Technology
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• v.22 no.2
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• pp.1-5
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• 2023

In the past, display devices have undergone many changes, such as plasma TVs and LCDs, and have continued to develop. Recently, new display technologies, such as Organic Light Emitting Diode displays and Inorganic Light Emitting Diode displays, have been developed. Among them, Micro LED displays have the potential to improve performance more than LCDs and OLEDs, but a lot of effort and time are needed until the mass production technology (transfer and bonding) of Micro LED displays is developed. We have developed a new Micro LED display light source that can be produced using existing transfer and bonding process technologies to enable faster commercialization of Micro LED in the industry. This light source is TFT deposition on LED. TFT deposition on LED has the advantage of being able to produce displays using existing process technology, making early commercialization of display application products possible. In this study, we applied the Active Driving method to verify the performance of TFT deposition on LED as a display to determine its commercialization potential. Additionally, to facilitate faster application of Micro LED in the industry, we applied TFT deposition on LED to Optical Wireless Communication systems, which are widely used in application service areas such as safety/security and sensors, to verify its communication performance. The experimental results confirmed that TFT deposition on LED is not only capable of AM driving but can also be applied to OWC systems.

• Journal of Korean Tunnelling and Underground Space Association
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• v.12 no.5
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• pp.399-405
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• 2010

The accumulated displacements and fatigues of rock are increased by the stress-hysteresis, induced from repeated frost-thawing. Also the shear strength is decreased by them continuously. The stress-hysteresis is affected by the atmospheric temperature changes, whose behavior is visco-elasticity, usually. Therefore, to do ideal body analysis, Kelvin model could be used to analyze the frost-thawing behavior in winter. In general, rock slope failure occurs by the deterioration of rocks, which is caused by the repetition of freezing-thawing process. In order to keep the safety of such rock mass structures the deterioration process of rock needs to be described quantitatively using some meaningful parameters. In this work, the deterioration process in freezing-thawing cycle of tuff, which is a famous soft porous rock, is investigated through laboratory tests and successfully described as a differential equation for the change of porosity. And then, the deterioration of the mechanical properties of rock, such as Young's modulus and uniaxial compressive strength, are quantitatively described as a function of the porosity.

• Journal of the Korean Society of Food Culture
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• v.25 no.5
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• pp.558-567
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• 2010

Changes in social, economical, and cultural environments affect the meal practices of children. The transmission of traditional Korean food culture is very important because it presents not only a well-balanced diet but also contributes to shaping identity. The purpose of this study was to investigate elementary school students' present meal practices and views, as well as demands on traditional food culture education to reflect future educational plans. Half of the students ate breakfast everyday and 72% ate a traditional Korean style breakfast. About 38% of the students participated 2-4 times per week in meal preparation and 34% participated in clean-up after the meal once a day. Although 6th graders had greater skills in basic cooking, they tended to be more passive upon applying their skills in daily meal practice. For traditional food culture education, 89% of the experienced and 86.2% of the inexperienced groups agreed on the necessity of traditional food culture education. Students attained traditional food culture knowledge through Silgwa, practical coursework within the curriculum, and by teachers leading classes. They were also educated by parents, mass media, and books outside of school. The preferred methods of class teaching were lecture and experiential learning. The preferred subjects to learn were 'cooking classes based on taste development', 'learning food ingredients through vegetable growing', 'traditional Korean food manners', and 'traditional Korean food culture and seasonal foods' as well as nutritional education. Fifth graders had more positive attitudes towards meal practices and traditional food culture education. Traditional Korean food culture and nutrition education should be integrated and developed into regular subject curricula to improve children's meal practice and inheritance of traditional food culture.

• Sleep Medicine and Psychophysiology
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• v.29 no.1
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• pp.4-8
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• 2022

Obesity hypoventilation syndrome (OHS) is defined as the triad of obesity (body mass index, [BMI] ≥ 30 kg/m²), daytime hypercapnia (PaCO2 ≥ 45 mm Hg), and sleep breathing disorder, after excluding other causes for hypoventilation. As the obese population increases worldwide, the prevalence of OHS is also on the rise. Patients with OHS have poor quality of life, high risk of frequent hospitalization and increased cardiopulmonary mortality. However, most patients with OHS remain undiagnosed and untreated. The diagnosis typically occurs during the 5th and 6th decades of life and frequently first diagnosed in emergency rooms as a result of acute-on-chronic hypercapnic respiratory failure. Due to the high mortality rate in patients with OHS who do not receive treatment or have developed respiratory failure, early recognition and effective treatment is essential for improving outcomes. Positive airway pressure (PAP) therapy including continuous PAP (CPAP) or noninvasive ventilation (NIV) is the primary management option for OHS. Changes in lifestyle, rehabilitation program, weight loss and bariatric surgery should be also considered.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.26 no.2
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• pp.99-115
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• 2023

Purpose: Exclusive breastfeeding promotes gut microbial compositions associated with lower rates of metabolic and autoimmune diseases. Its cessation is implicated in increased microbiome-metabolome discordance, suggesting a vulnerability to dietary changes. Formula supplementation is common within our low-income, ethnic-minority community. We studied exclusively breastfed (EBF) neonates' early microbiome-metabolome coupling in efforts to build foundational knowledge needed to target this inequality. Methods: Maternal surveys and stool samples from seven EBF neonates at first transitional stool (0-24 hours), discharge (30-48 hours), and at first appointment (days 3-5) were collected. Survey included demographics, feeding method, medications, medical history and tobacco and alcohol use. Stool samples were processed for 16S rRNA gene sequencing and lipid analysis by gas chromatography-mass spectrometry. Alpha and beta diversity analyses and Procrustes randomization for associations were carried out. Results: Firmicutes, Proteobacteria, Bacteroidetes and Actinobacteria were the most abundant taxa. Variation in microbiome composition was greater between individuals than within (p=0.001). Palmitic, oleic, stearic, and linoleic acids were the most abundant lipids. Variation in lipid composition was greater between individuals than within (p=0.040). Multivariate composition of the metabolome, but not microbiome, correlated with time (p=0.030). Total lipids, saturated lipids, and unsaturated lipids concentrations increased over time (p=0.012, p=0.008, p=0.023). Alpha diversity did not correlate with time (p=0.403). Microbiome composition was not associated with each samples' metabolome (p=0.450). Conclusion: Neonate gut microbiomes were unique to each neonate; respective metabolome profiles demonstrated generalizable temporal developments. The overall variability suggests potential interplay between influences including maternal breastmilk composition, amount consumed and living environment.

• Journal of the Korean Society of Food Culture
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• v.23 no.3
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• pp.403-409
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• 2008

Recently, the desire for low body weight, which is an abnormal weight construct along with obesity, has become an evident and serious problem in teenagers. In Korea, the desire for low weight is not perceived as an important problem, but it is rapidly expanding relative to the physical changes and developmental issues teenagers experience. The social atmosphere presented through mass media is the key influencer for the increasing low weight occurrence in teenagers. Because thoughts about beauty have changed among people, and since there is apparent blind interest in slim body shape and appearance, already low-weight individuals are attempting to lose weight along with obese persons. Thus, we consider it necessary to guide teenagers toward having correct perceptions with regard to weight and their own body shape, and that a healthy and appropriate weight is beautiful. Therefore, for this study, we investigated body perception, abnormal weight, attitude toward weight control, and factors related to eating behavior among teenage girls, who are considered the at risk group for overt body weight control behavior. Based on this, we have attempted to set in motion a systematic and active nutrition education program that will allow us to increase body satisfaction by educating on nutritional issues related to development, and ultimately, implant healthy body shape perceptions.

• Journal of the Korean Society of Food Culture
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• v.23 no.6
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• pp.820-833
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• 2008

The study analyzed the body shape perception, weight control attitude, nutrition knowledge, and dietary habits of 529 high school students in Jeju surveyed from January 14-18, 2008 according to students' body shape satisfaction, with the aim of providing basic nutritional education data to aid in appropriate weight control for high school students. The data were analyzed by descriptive analysis, T-test, Chi-square test, ANOVA, and Pearson's correlation coefficients, using the SPSS Win 12.0 program. The body mass index (BMI) of subjects was in the normal range. With regard to weight distribution, 59.4% of subjects showed normal weight and girls were significantly more underweight than boys. More girls considered themselves to be fatter than boys and tended to be increasingly dissatisfied with their body shape. Both boys and girls were more interested in weight control for obesity and were significantly less satisfied with their body shape. Efforts at weight control and reduction had occurred significantly more often for girls than for boys. Dietary attitude scores were significantly higher in girls than boys. BMI positively correlated to weight control concern and nutrition knowledge positively correlated to dietary attitude. BMI negatively correlated to the body shape satisfaction, which in turn negatively correlated to food ingestion disorders. Therefore, it is necessary to develop a systematic nutrition educational program that can induce changes in dietary behavior and increase accurate perception and satisfaction of body shape.

• Korean Journal of Legislative Studies
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• v.27 no.1
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• pp.41-77
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• 2021

It has been 20 years since the gender quota system for expanding women's political representation was enacted. However, the proportion of Korean women's representatives has not exceeded 20 percent. This study examines how the gender quota system, public funding for women candidates, and public funding for women's development, which are the three pillars of the legal system to expand women's representation, have changed systematically over the past 20 years, how they affected women's representation, and what institutional limitations they have. In addition, it explores the im/possible conditions of reforms for expanding women's representation. To reform the legal system for women's representation, it is necessary to understand that Korea's political system is arranged in a gender-based way in a male-dominated structure, while also understanding that the existence of critical actors and mass driving reforms for gender equality in politics is essential.