• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.614-614
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• 2012

개수로에서 혹은 수리구조물 주변에서의 흐름 및 난류 특성을 파악하기 위해서는 연직유속분포 및 수심별 평면유속분포의 측정이 필요하다. 유속분포를 측정하기 위한 방법은 음파 도플러 유속계(ADV:Acoustic Doppler Velocimetry)를 사용하는 방법과 PIV 기법을 이용하는 방법이 있다. 일반적으로 ADV는 한 지점의 유속을 시간변화에 따라 연속적으로 측정할 수 있어 난류특성의 정량적인 해석에 장점이 있으나 동시간에 여러 지점을 측정할 수 없기 때문에 난류의 공간적인 문제를 해석함에 있어서 한계가 있다. 그러나, 입자영상유속계(PIV:Particle Image Velocity)는 측정하고자 하는 단면에서 연직 횡단면의 유속분포 및 수심별 평면 유속분포 흐름장 측정이 가능하여 난류흐름의 공간적인 문제를 해석하는데 효과적일 뿐만 아니라 영상간의 시간간격을 짧게 하고, 촬영시간을 충분히 길게 한다면 개수로 내 난류특성 분석도 가능하다. 이에 본 연구의 목적은 PIV 기법을 이용하여 매끄러운 하상의 개수로에서 연직유속분포를 측정하고 그 특성을 정량적으로 분석하고자 한다. 본 연구에서는 첫째, PIV 기법을 이용하여 측정한 연직유속분포와 3차원 전자식 유속계를 이용하여 측정한 연직유속분포를 비교 분석하였다. 둘째, 후류법칙에 의해 계산된 연직유속분포와 PIV 기법을 이용하여 측정한 연직유속분포의 비교를 위해 각각의 무차원 유속분포(지점 유속/지점 마찰속도)를 계산하고 비교하였다. 마지막으로 각 흐름 조건에 따라 수심의 변화를 주어 연직유속분포를 PIV 기법으로 측정한 후 개수로의 수심변화에 따른 연직유속의 특성을 분석하였다. 분석 결과, PIV 기법을 이용하여 측정한 연직유속 성분에 비해 3차원 전자식 유속계로 측정한 연직유속 성분이 작게 나타났고 바닥에서부터 0.2h 지점까지는 무차원 유속분포(지점 유속/지점 마찰속도)가 후류법칙과 잘 맞는 경향을 보였으나 0.2h 지점부터 수표면까지는 유속이 감소하는 현상이 나타났다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.6
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• pp.438-445
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• 2019

In this paper, we present a new approach to extract the g-sensitivity scale-factor error for a MEMS gyroscope. MEMS gyroscopes, based on the use of both angular momentum and the Coriolis effect, have a g-sensitivity error due to mass unbalance. Generally, the g-sensitivity error is not considered in general use of gyroscopes, but it deserves our attention if we are to develop for tactical class performance and reliability. The g-sensitivity error during vehicle flight increases navigation error; so it must be analyzed and compensated for the use of MEMS IMU for high dynamics vehicle systems. Therefore, we analyzed how to extract the g-sensitivity scale-factor error from the inertial sensor error model. Furthermore we propose a new method to extract the g-sensitivity error using flight motion simulator. We verified our proposed method with experimental results.

• Proceedings of the Korean Society of Disaster Information Conference
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• 2015.11a
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• pp.193-194
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• 2015

본 연구는 요인분석을 통해 노인 보행자 사고 유형을 대표할 수 있는 성분 값을 계산하고 군집분석을 실시하여 노인 보행자 사고 취약 지역을 선정하는 모델을 확인하였다. 기존 노인보행자 사고에 관한 연구는 보행 환경 분석 및 노인보행자 사고 특성을 확인한 뒤, 제도적, 물리적 환경 개선 등에 대한 정책 제언의 형식으로 진행되었다. 이러한 연구는 실질적으로 노인 보행자 특성을 분석하여 사고를 감소시키는 연구가 아닌, 일반적으로 알려진 사실이나 해외 사례를 들어 노인 보행자 사고의 현 실태에 대해 어느 정도 환기만 시켜주는 역할로 그쳤다. 이러한 점에서 군집분석을 통한 노인 보행자 사고 취약지역 선정은 노인 보행자 사고 특성의 비교를 명확하게 할 수 있도록 새로운 기준을 제시하였다. 이에 기존의 방법론에서 벗어나 실질적으로 노인 보행자 사고 방지 대책이 시급한 지역을 선정하였고, 노인 보행자 사고에 관해 활발히 연구 시킬 것이라 예상한다. 군집분석을 사용하는 핵심은 사망자 수와 사망률이 상대적으로 동시에 높은 군집을 선정할 수 있고 지역 특성 비교를 통해 향후 노인 보행자 사고에 관한 추가 연구가 가능할 것으로 기대한다.

• The Korean Journal of Food And Nutrition
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• v.25 no.4
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• pp.1092-1098
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• 2012

Aroma compounds in sun-dried salt according to saltern material and packaging box were extracted by the headspace and were isolated by using GC-MS. These compounds were identified including ketones, heterocyclic compounds and six other compounds. Major aroma compounds in salts were identified as 4-methyl-2-pentanone, 5-methyl-3-hexanone, 4-methyl-3-penten-2-one, 2-hexanol, benzothiazole, 2,4-bis(1,1-dimethylethyl)-phenol, and 1,3,5-tri-tert-butyl benzene. However, we found no significant differences according to the saltern materials in three salts. Salts stored in Chamaceyparis obtusa (Sieb. et Zucc.) had more diverse aroma profiling than those in Pinus densiflora and Paulownia coreana. We consider that it need to research the development of high value added products for new aromatic salt.

• Development and Reproduction
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• v.11 no.3
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• pp.195-203
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• 2007

Sex determination and sex differentiation are influenced by genotype in many gonochoristic fish. Cytochrome P450 aromatase (CYP19) is the terminal enzyme in steridogenic pathway that converts androgens into estrogens. In this study, partial fragments of aromatase genes (ovarian aromatase, P450aromA and brain aromatase, P450aromB) were cloned and sequenced in Korean rockfish (Sebastes schlegeli), and gene specific primers were designed based on their sequences. Using these primers, aromatase gene expression during sex differentiation was investigated by RT-PCR. Expression of these aromatase genes were detected both in the head and body parts at 35 dab (days after birth). The number of fish that expressed the aromatase genes decreased at 52 dab, implying down-regulation of these genes. However, these genes were expressed at 59 dab in almost all fish studied here. The expression patterns of both genes are similar throughout the investigated period except for 45 dab where the expression of P450aromB was detected in more fish than that of P450aromA both in the head and body parts. Timing of sex differentiation in this species has been shown to be at around $50{\sim}65$ dab by histological analysis. However, the results from this study suggest that sex differentiation of rockfish may take place $1{\sim}2$ weeks earlier than the period proposed previously. The results also suggest that the mechanism of sex differentiation in viviparous fish may be similar to that in oviparous fish in terms of the importance of aromatase action during the critical period.

• Food Science and Preservation
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• v.5 no.3
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• pp.262-269
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• 1998

In order to promote the applications of Korean loquat leaf as food, loquat leaf tea was manufactured and its physicochemical characteristics were examined. The contents of moisture, crude fat and ash of loquat leaf collected in the middle of February were lower than those collected in October. Mineral contents after 4 times of roasting loquat leaf between February and October were higher 39,916.8 ppm and 23,950.0 ppm of K, respectively. The contents of ascorbic acid(2.33%), free sugar(fructose 1.01%), tannin(1.63%) and caffein(113 mg%) were higher in October than those February. The chromaticity and absorbance of loquat leaf tea percolate were higher in 2 times of roasting but were lower 4 times of roasting in October than those in February. In free amino acid of its percolate and volatile component of 4 times of roasting leaf tea collected in October, DL-allohydroxylysine and nerolidol were higher, respectively.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.11B
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• pp.1546-1555
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• 2001

Conventionally, in a CDMA system analysis, we assume only a single path within one chip duration. But, in this paper, we assume various number of multipaths within one chip duration according to spreading bandwidth in fixed channel model. Thus we take into account of the effects of autocorrelation and relative phases among multipath components within one chip duration according to different bandwidth, and analyze fading effects. And we derive the pdf of output signal. Then, we derive the average error probability versus the number of users from derived pdf. We use a Maximal Ratio Combining (MRC) RAKE receiver under the JTC channel model which is one of the popular realistic wideband channel models. And we employ hybrid FDMA/CDMA systems to compare the performance of W-CBMA system for the same occupied total bandwidth. Then, we compare and analyze them for different bandwidth based on the number of users as a parameter. From the simulation results for different bandwidth, better performance can be obtained for wider bandwidth system where more resolvable multipath components are available.

• Journal of Bio-Environment Control
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• v.4 no.1
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• pp.43-49
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• 1995

The main purpose of these studies were to clarify differences in Cheju - scoria and other solid media on quantity and quality of cherry tomatoes and on shift of component of the nutrient solution, and to use Practically Cheju-scoria as an excellent solid culture medium. The results obtained were summarized as follows ; 1. Among scoria plots, the rates of dry weights, fruits and their sugar-acid ratio were higher in the plot that was drained well with deep flow for one hour once a day. 2. Fresh fruit weights were lighter in rockwool and deep flow technique, but larger in scoria, Hyugashi (artificial gravel, $\Phi$10-12mm) and perlite in moving to higher flower cluster. 3. The results of analysis on microelement among solution components showed decrease of concentrations of P and K in the period of growth and development. 4. Yields and brix of cherry tomato showed a tendency to increase in rockwool and Hyugashi than anothers. 5. The concentration of fertilizer base was increased in general solution culture. Transpiration and absorption were similar in scoria plot and other media. 6. More studies of the Cheju-scoria development is required in order to use it as a solid medium for solution culture.

• Journal of Korean Society of Forest Science
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• v.88 no.4
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• pp.562-567
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• 1999

Dendropanax morbifera Lev. leaves were collected during different seasons to analyze the chemical components. In proximate composition the leaves collected in spring had the highest moisture content and in winter had the lowest. Lipid, ash and fiber contents gradually increased from spring to winter and in winter had the highest. Protein content decreased until summer and then it increased. All of free sugars detected have gradually increased during the growing season. Unsaturated fatty acids content was higher than that of the saturated fatty acids and the major saturated and unsaturated fatty acids were arachidic acid and cis-13,16-docosadienoic acid. respectively. Fifteen free amino acids detected with arginine content being the highest regardless of season and amino acid content gradually decreased during the seasons. The highest content of mineral elements was potassium in leaves collected in spring, with calcium was the highest in leaves picked in other seasons. Vitamin C content was gradually decreased over the growing season and soluble tannin content increased notably.

• Journal of the Korean Society of Food Science and Nutrition
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• v.13 no.4
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• pp.377-380
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• 1984

Nutritional evaluation of the proposed supplementary foods (high nutrition-low cost foods) for children were conducted for the ‘Wonseong County Comprehensive Nutrition Program’ in Korea. Proximate composition, mineral, vitamin and amino acid composition were determined and also protein efficiency ratio(PER) was evaluated for the propsed formulas which were recommended as CSS (corn-soybean-sesame blend)-3, CSS-4 and BSS (barley-soybean-sesame blend)-4 in previous study. Protein and caloric contents of the formulas were around 18% and 400 Kcal/100 g respectively, and they have reasonable contents of mineral and vitamin. Amino acid score (83-89) and PER (2.33-2.36) of the proposed formulas were considered to be in adequate range of protein quality for feeding the target group in Wonseong County area.