• Journal of Advanced Navigation Technology
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• v.25 no.1
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• pp.29-39
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• 2021

As a means of solving traffic congestion in the downtown of large city, the interest in urban air mobility (UAM) using electric vertical take-off landing personal aerial vehicle (eVTOL PAV) is increasing. eVTOL configurations that will be used for UAM are classified by lift-and-cruise, tilt rotors, tilt-wings, tilted-ducted fans, multicopters, depending on propulsion types. This study tries to perform preliminary conceptual design for a given mission profile using reverse engineering techniques by taking the multicopter type Airbus's CityAirbus as a basic model. Wetted area, lift to drag ratio, drag coefficients were calculated using the OpenVSP which is an aerodynamic analysis software. The power required for each mission section of CityAirbus were calculated, and the corresponding battery and motor were selected. Also, total weight was predicted by estimating component weights of eVTOL.

• Journal of Broadcast Engineering
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• v.20 no.6
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• pp.818-826
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• 2015

Recently, objective image quality assessment (IQA) methods that elaborately reflect the visual quality perception characteristics of human visual system (HVS) have actively been studied. Among those characteristics of HVS, luminance adaptation (LA) effect, indicating that HVS has different sensitivities depending on background luminance values to distortions, has widely been reflected into many existing IQA methods via Weber's law model. In this paper, we firstly reveal that the LA effect based on Weber's law model has inaccurately been reflected into the conventional IQA methods. To solve this problem, we firstly derive a new LA effect-based Local weight Function (LALF) that can elaborately reflect LA effect into IQA methods. We validate the effectiveness of our proposed LALF by applying LALF into SSIM (Structural SIMilarity) and PSNR methods. Experimental results show that the SSIM based on LALF yields remarkable performance improvement of 5% points compared to the original SSIM in terms of Spear rank order correlation coefficient between estimated visual quality values and measured subjective visual quality scores. Moreover, the PSNR (Peak to Signal Noise Ratio) based on LALF yields performance improvement of 2.5% points compared to the original PSNR.

• Journal of the Korean GEO-environmental Society
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• v.21 no.10
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• pp.5-10
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• 2020

As the demand for the recycling of industrial by-products increases due to various environmental restrictions including the prohibition of ocean disposal, various studies regarding the recycling of industrial by-products are currently being carried out. One of the industrial by-product, coal ash is produced from thermal power generation; studies on the recycling of fly ash have been actively carried out and it is currently recycled in various fields. In the case of bottom ash, however, only a portion of the total amount generated is primarily processed into a particle size of 2~4mm or less than 2mm to be used for gardening purpose and light weight aggregate and so on. The remaining amount is buried at ash disposal sites. Therefore, various studies are needed to develop measures to use bottom ash. This study aimed at identifying the optimal particle size and mixing ratio of bottom ash to be used as CLSM aggregate. To this end, it evaluated the usability of bottom ash as CLSM aggregate, by investigating the flowability and strength change characteristics of CLSM produced with regard to the mixing ratio of weathered granite soil and bottom ash, particle size of bottom ash to be mixed and soil binder addition rate and conducting a heavy metal leaching test.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.31 no.3
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• pp.366-374
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• 1986

Taiwan land race, Taichung 2 rowed barley #1 was crossed with England cultivar, Deba abed in 1972, and two isogenic lines-lax and compact heads-were made in 1982. So as to three fertilizer and three seeding density levels were treated at Dan-Kook Agricultural College farm located in Cheonan in 1984-1985. Lax head type had longer spike length and rachis than compact type. The traits uninfluenced by different head types were heading time, number of grains per spike, yield and soluble nitrogen content. However, the traits related to malting quality such as 1,000 grain weight, assortment ratio, protein content of grain and malt, malt extract, malt total nitrogen content, Kolbach index and diastatic power were significantly affected by head types. The number of spikes per m2, yield, assortment ratio, crude protein content of grain and malt yield ratio, extract yield ratio, malt total nitrogen, souble nitrogen content, Kolbach index and diastatic power were affected by fertilizer and seeding density levels in both isogenic lines. The malting quality was best at 12-12-9 kg/l0a fertilizer level and the yield was greatest at 15-12-9 kg/l0a level. Narrow-spaced or drilling seeding had greater yield and better malting quality than conventional row seeding. The plant with lax head type had some advantages in malting quality, suggesting that this trait would be considered as an selection criterion fer good malting quality lines.

• Korean Journal of Community Nutrition
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• v.13 no.1
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• pp.46-61
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• 2008

The purpose of this study was to investigate the effect of nutrition counseling on improving metabolic syndrome (MS) risk factors. Sixty-eight subjects were grouped according to their numbers of MS risk factors. Subjects who have three or more risk factors of MS were defined as "High risk", subjects who have two risk factors of MS were defined as "low risk", and subjects who have below two risk factors of MS were defined as "no risk" group. All groups finished nutrition counseling every three weeks for 12 weeks. Anthropometric, dietary assessments (24 hr-recall) and blood samples were measured at 0 and 12 weeks nutrition counseling. After 12 weeks of intervention, anthropometric data (weight, BMl, body fat (%), and waist/hip ratio) were significantly decreased (p < 0.05) in all groups. Daily consumption of calorie was decreased significantly (p < 0.05) in the group of low risk and high risk. Blood level of fasting plasma glucose was significantly decreased (p < 0.001) in all groups after 12 weeks of intervention. Significantly, the fasting plasma glucose level was returned to normal range in the high risk group. The number of people who have three or more risk factors of MS (high risk group) was decreased from 25 to 12. Sum of MS Criteria decreased from 85 to 52 in the group of MS and decreased from 143 to 99 in all groups. These results indicate that nutrition counseling for male workers at the worksite proved to be helpful by reducing the risk factors of MS and thereby reducing the risk of cardiovascular disease. Continuing and systematic nutritional management programs should be developed and implemented for male workers at the worksites.

• Journal of Nutrition and Health
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• v.37 no.6
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• pp.423-430
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• 2004

This study was performed to evaluate the effect of red-yeast-rice on bone metabolism in overiectomized (OVX) rats. Forty female Sprague-Dawley rats (body weight 210 $\pm$ 5 g, 9 weeks old age) were divided into two groups. One group were OVX, and the other group received sham operation (SHAM), and received either control diet (20％ casein) or a red-yeast-rice power supplemented diet (0.1％) for 9 weeks. And then each rat group was further divided into control diet (casein 20％) and red-yeast-rice powder supplemented (0.1％) diet group. All rats were fed on experimental diet and deionized water ad libitum for 9 weeks. Bone mineral density (BMD) and bone mineral content (BMC) were measured using PIXImus (GE Lunar Co, Wisconsin, USA) in spine and femur on 5, 9 weeks after feeding. The serum and urine concentrations of Ca and P were determined. Bone formation was measured by serum osteocalcin and alkaline phosphatase (ALP) concentrations. And bone resorption rate was measured by deoxypyridinoline (DPD) crosslinks immunoassay and corrected for creatinine. Serum osteocalcin, growth hormone, IGF-l and calcitonin were analyzed using radioimmunoassay kits. Urinary Ca and P excretion were not significantly different among the groups. Within the OVX group, the red-yeast-rice group had a lower crosslinks value than the casein group. Therefore the red-yeast-rice supplemented groups had a lower bone resorption ratio than the casein group in the ovariectomized rats. And, the red-yeast-rice group had significantly higher IGF-l hormone than casein group in ovariectomized rats. The red-yeast-rice group had higher spine bone mineral content than those of control group within the OVX groups. This study was an important first step in establishing that the observed beneficial effects of red-yeast-rice on bone, and this study also established the need for a study on the long-term effect of this supplement in a human.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.3
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• pp.289-293
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• 2004

PNW-PMN-PZT ceramics were fabricated with the variations of Nb$_2$O$_{5}$ addition and their microstructural and piezoelectric characteristics were investigated. When the amount of Nb$_2$O$_{5}$ increased, grain size decreased gradually. At 0.3wt％ Nb$_2$O$_{5}$ which is the same weight percent with Fe$_2$O$_3$, maximum tetragonality(c/a) and density were shown due to the complexed doping effects. Also, this composition that showed Qm of 2,041, kp of 0.55, grain size of 2.5${\mu}{\textrm}{m}$ and $\varepsilon$r of 1704 were proper for high power application. Using this composition, Rosen-type piezoelectric transformer was fabricated as the size of 1 ${\times}$ 16 ${\times}$ 5㎣ and its electrical characteristics were investigated with the variations of load resistance and driving frequency. At the resistance of 200㏀, maximum step-up ratio of 13.68 was shown. After driving PDA CCFL for 25 min using the inverter circuit, at driving frequency of 214.4KHz, input voltage of 31.78 V and input current of 21.1mA were measured at the input part of piezoelectric transformer. And then, output voltage of 293.2 V and output current of 2.2mA were shown at the output part of piezoelectric transformer. At the same time, efficiency of 96.2％ and temperature rise of 3.5$^{\circ}C$ were appeared at the piezoelectric transformer.ormer.

• Korean journal of food and cookery science
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• v.21 no.3 s.87
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• pp.326-338
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• 2005

The purpose of this study was to investigate the effect of isolate soybean protein (ISP) and rice flour on the characteristics of rice noodles. As the levels of ISP and rice flour increased, water binding capacity, swelling power of rice noodle increased. In RVA, pasting temperature, Set back showed an increasing tendency with peak viscosity, holding viscosity, break down, final viscosity of rice noodle increased as the level of rice flour by decreasing. Peak time was not significant. The weight, water absorption and volume of the cooked noodles were decreased. The turbidity of rice noodle increased. The Hunter color L, a-values of the dried rice noodle decreased. Cooked rice noodle quality increased with by decreasing the level of rice flour level. B-values of dried rice noodle and cooked rice noodle increased. Texture profile analysis of cooked rice noodle showed an increase of hardness. Adhesiveness, cohesiveness of cooked rice noodles decreased with by decreasing the level of ISP and rice flour. Gumminess, springiness, chewiness were increased. Sensory evaluation, showed gloss was increased. Hardness and chewiness of the cooked ice noodles were increased. Adhesiveness was not significant. Color and overall- acceptability were increased. Relationship between sensory and mechanical examinations (The overall quality of sensory examination for gloss) had a negative correlation with the mechanical examination for b-value (p.0.05). Mechanical examination for b-value had a positive correlation of sensory evaluation for hardness, chewiness, which had negative correlation of sensory evaluation for color. Scanning Electron, Microscopes observation of rice noodle was showed that the size of the hole grown was increased with by increasing the level of rice flour. From the above results, the most advisable mixture ratio of rice noodle evaluation was can be derived as follows: 171g rice flour, 114g wheat flour, 15g soybean protein isolate, 120ml water, and 6g salt.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.2
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• pp.221-227
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• 2016

The main shaft is one of the key components connecting the rotor hub and gear box of a wind power generator. Typically, main shafts are manufactured by open die forging method. However, the main shaft for large MW class wind generators is designed to be hollow in order to reduce the weight. Additionally, the main shafts are manufactured by a casting process. This study aims to develop a manufacturing process for hollow main shafts by the open die forging method. The design of a forging process for a solid main shaft and hollow shaft was prepared by an open die forging process design scheme. Finite element analyses were performed to obtain the flow stress by a hot compression test at different temperature and strain rates. The control parameters of each forging process, such as temperature and effective strain, were obtained and compared to predict the suitability of the hollow main shaft forging process. Finally, high productivity reflecting material utilization ratio, internal quality, shape, and dimension was verified by the prototypes manufactured by the proposed forging process for hollow main shafts.

• Polymer(Korea)
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• v.37 no.6
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• pp.694-701
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• 2013

A new copolymer named T-TI24T (poly((5,5-(2-butyl-5,6-bisdecyloxy-4,7-di-thiophen-2-yl-isoindole-1,3-dione))- alt-(2,5-thiophene))) based on phthalimide derivative and thiophene is synthesized by the Stille-coupling reaction. The polymer shows relatively high number average molecular weight of 86500 g/mol with good solubility in common organic solvents such as chloroform, 1,2-dichlorobenzene, and toluene and is thermally stable up to $380^{\circ}C$. Besides, it possesses a relatively low highest occupied molecular orbital (HOMO) energy level of -5.33 eV, promising the high open circuit voltage ($V_{oc}$) for photovoltaic applications. Active layer solution of polymer T-TI24T-as a donor and (6)-1-(3-(methoxycarbonyl)- {5}-1-phenyl[5,6]-fullerene (PCBM)-as an acceptor in different weight ratios is applied to fabricate the polymer solar cell devices. The ratio of polymer/PCBM affects the solar cell efficiency and the best performance exhibits in the device with polymer/PCBM = 1:3 (w/w), which shows a power conversion efficiency (PCE) of 0.199% and a $V_{oc}$ of 0.99 V, respectively. Even though the device shows the very low PCE, the $V_{oc}$ is higher than that of well known bulk heterojunction type solar cell based on P3HT:PC61BM (c.a. 0.5 V).