• 조명전기설비학회논문지
• /
• 제19권6호
• /
• pp.52-58
• /
• 2005

Micro-Grid의 개념은 CERTS(Consortium for Electric Reliability Technology Solutions)에 의해 제안된 새로운 분산 전원 망으로서 부하에 열과 수 $[KW]{\sim}1[MW]$ 사이의 전력을 함께 제공하는 Micro-Source에 의해 구성되어 있다. Micro-Source는 친환경적인 연료전지나 마이크로터빈 등을 에너지원으로 사용하며, 전력품질 제어를 위해 전압형 인버터를 채용하고 독립적인 유무효전력 제어가 가능한 새로운 개념의 분산전원이다. Micro-Source가 효율적으로 유효전력 및 무효전력을 전력시스템에 공급하기 위해서는 계통연계용 인덕터가 필요한데, 본 논문에서는 인덕터의 제어 범위와 각 변수의 한계를 함께 고려하고 전달 및 제어하고자 히는 유효 및 무효 전력의 범위에 의해 인덕터 용량을 결정하는 절차를 제안하였다.

• 한국의류학회지
• /
• 제34권1호
• /
• pp.79-91
• /
• 2010

This study investigates the differences between purchasers and non-purchasers of naturally dyed-products in the hobby/leisure, media exposure, usage of media program type, and information sources about naturally dyed-products. Data were collected from a total 213 Korean females ranging from 20 to 59 years old, and in data analyses, there were partially significant differences between the two groups. Compared to non-purchasers of naturally dyed-products, Purchasers of those ones were more interested in traditional fields and nature. They are also more exposed to newspapers and less exposed to TV. Purchasers used more informational and educational programs as well as personal and commercial information sources (store visual presentations and sales persons) than non-purchasers. However, the differences between these two groups were not significant in the interests of fashion/cooking and sports, Internet exposure, entertainment programs and public/commercial information sources about naturally dyed-products. Marketers can use the results to access the market of naturally dyed-products for promotion.

• 한국소음진동공학회논문집
• /
• 제19권7호
• /
• pp.710-718
• /
• 2009

The time difference of arrival(TDOA) algorithm is being used widely for identifying the location of a source emanating either electrical or acoustic signal. It's application areas will not be limited to identifying the source at a fixed location, for example the origin of an earthquake, but will also include the trajectory monitoring for a moving source equipped with a GPS sensor. Most of the TDOA algorithm uses time correlation technique to find the time delay between received signals, and therefore difficult to be used for identifying the location of multiple sources. In this paper a TDOA algorithm based on cross-spectrum is developed to find the trajectory of two sound sources with different frequencies. Although its application is limited to for the sources on a disk plane, it can be applied for identifying the locations of more than two sources simultaneously.

• Asian-Australasian Journal of Animal Sciences
• /
• 제11권1호
• /
• pp.13-16
• /
• 1998

A $2{\times}2{\times}4$ factorial study was conducted to examine the possibility of improving estimates of in vitro digestibility, using untreated (UBS) and ammonia-treated (ABS) barley straw, through homogenization of rumen fluid (RF) and by additions of urea (U) and casein (C) as N sources and Xylose + Glucose (XG) as energy sources into artificial saliva. Digestibiltiy of ABS was significantly greater than that of UBS (p < 0.001). There was a significant decrease in digestibility when additions (U, UC, UCXG) were compared with the control (p < 0.001). A 2-way interaction between RF and straw type was significant (p < 0.05) for dry matter digestibility (DMD). Homogenization of RF increased DMD of ABS (p < 0.05) whereas it decreased DMD of UBS (p > 0.05). The study showed that addition of N alone or in combination with energy sources was not better than control, rather the reverse, digestion was inhibited by a combination of U and casein (UC). It was concluded that sufficient N and branched chain fatty acids were supplied in the inoculum from sheep fed high protein grass cubes to support the growth of cellulolytic microbes during in vitro incubation. Further studies are, however, required to explore the potential of homogenization in improving the in vitro method to estimate digestibility of cereal straws.

• 정보관리학회지
• /
• 제28권4호
• /
• pp.201-220
• /
• 2011

이 연구에서는 우리나라 토목공학분야 연구자들이 참조하는 정보원의 유형을 인용분석을 통해 조사하였다. 분석 결과는 다음과 같다. 1) 주요 인용정보원은 학술지(55.7%)와 단행본(15.6%)과 회의자료(10.2%) 순이었다. 2) 출판 후 10년 이내(26.1%)의 문헌을 가장 많이 인용하였다. 3) 핵심학술지는 국내학술지였으며, 상위권 핵심학술지 선호도에서도 국내와 국외문헌의 의존도가 유사하였다. 4) 최신자료의 경우 국내문헌을, 출판 이후 경과시간이 오래된 자료의 경우 국외문헌을 선호하였다. 5) 국내외 모든 핵심학술지들이 영향력 지수와 즉시성 지수의 값이 동시에 높게 나타나지 않았다.

• Asian-Australasian Journal of Animal Sciences
• /
• 제10권4호
• /
• pp.357-363
• /
• 1997

The effect of replacement of cotton seed meal (CSM), with various levels and sources of non-protein nitrogenous (NPN), substances on in vitro ruminal fermentation were studied. Cotton seed meal, in control ration provided nitrogen equivalent to 12.5 percent crude protein while in experimental ration was replaced at 30, 50 & 70 percent levels with urea, diammonium phosphate (DAP) and biuret, respectively. The results of incubation upto 48 hours indicated an improvement in digestibility by replacement of CSM with urea and biuret upto 50 percent protein equivalent, but not with DAP. Bacterial count from cultures containing 50% nitrogen from biuret was significantly higher than DAP, urea and CSM. Various sources of nitrogen produced $NH_3-N$ in increasing order of CSM, biuret, DAP and urea. Increasing levels of NPN resulted in progressive increase in the levels of $NH_3-N$. The levels of various NPN sources had no effect on pH. However, the pH values determined for urea and CSM were higher than biuret and DAP.

• Asian-Australasian Journal of Animal Sciences
• /
• 제33권2호
• /
• pp.305-312
• /
• 2020

Objective: The present trial was conducted to determine the influence of different dietary fatty acid (omega-3 and omega-6) sources on reproductive performance of female broiler breeders and growth performance and carcass traits of their progeny. Methods: Two hundred and twenty, 25 weeks old Ross-308 male (20) and female (200) broiler breeders were used in the experiment for the period of 6 weeks. All birds were randomly divided into four dietary treatments (containing 2% soybean oil, 2% sunflower oil, 2% flaxseed oil, and 2% fish oil) each with five replicates of one male and ten females. Throughout this experiment hatching performance of broiler breeders, progeny growth performance and carcass parameters were recorded. Results: The results showed that the inclusion of different fatty acid sources in female broiler breeders diet had no significant effects (p>0.05) on number of fertile eggs, post-hatch mortality, and fertility rate. The soybean oil supplemented group had significantly (p<0.05) higher late embryonic mortality compared to other three treatments. Conclusion: It was concluded that inclusion of 2% of different sources of omega-3 and omega-6 fatty acids (especially 2% flax seed oil) in broiler breeders' diet can reduce late embryonic mortality. The other reproductive characteristics of parents and growth and carcass characteristics of progeny remained unaltered by dietary sources of omega-3 and omega-6 fatty acids.

• 한국대기환경학회지
• /
• 제18권4호
• /
• pp.275-284
• /
• 2002

Atmospheric concentrations of organochlorine pesticides (OCPs) in Seoul, South Korea between July 1999 and May 2000 were determined to investigate concentration distribution in air, relationship between concentrations and meteorological conditions, and apportionment of sources e.g. local sources (air- surface exchange) and long range transport. Endosulfan and $\alpha$-HCH were the highest concentrations in atmosphere with values typcally ranging from 10s to l00s of pg/㎥. These high concentrations may be attributed to their usage, period and chemical property (Koa). All OCPs also showed elevated levels during the summer and were positively correlated with temperature. This would suggest that a seasonal enhancement was due to (re)volatilization from secondary sources and application during the warmer months. The temperature dependence of atmospheric concentrations of OCPs were investigated using plots of the natural logarithm of partial pressure (In P) vs reciprocal mean temperatures (1/T), and environmental phase-transition energies were calculated for each of the pesticides. For OCPs, temperature dependence was statistically significant (at the 99.99% confidence level) and temperature accounted for 35~95% of the variability in concentrations. The relatively higher slopes and phase-transition energies for $\alpha$-, ${\gamma}$-chlordane, endosulfan and endosulfan sulfate suggested that volatilization from local sources influenced their concentrations. The relatively lower those for $\alpha$-, ${\gamma}$-HCH, p, p'-DDE and heptachlor epoxide also suggested that volatilization from local sources and long range transport influenced their concentrations.

• 한국대기환경학회지
• /
• 제13권4호
• /
• pp.285-296
• /
• 1997

The suspended particulate matters had been collected on quartz fiber fiters by a cascade impactor having 9 size stages for 4 years (Sep. 1991 to Dec. 1995) in Kyung Hee University-Suwon Campus. Membrane filters were used to collected the particulate matters on each stage. The weight concentration on each stage was obtained by a microbalance and further chemical element levels were determined by an x-ray fluorescence system. Based on these chemical information, our study focused on applying the target transformation factor analysis (TTFA), a receptor model, to identify aerosol sources and to apportion quantitatively their mass contribution. There are total of 63 ambient data sets. Each data set consists of the 8 size-ranged subdata sets characterized by 16 elemental variables. By the results, four to five sources were extracted from each size range and some sources reappeared in other size ranges. Then total of 8 source profiles were statistically generated from all the ranges, such as oil burning source, soil source, field burning source, gasoline related source, coal burning source, marine source, glass related source, and unknown sources. Apportioning aerosol mass to each source was intensively examined by investigating emission inventories near the study area. The results showed that soil particle source was the most significant contributor. However, coal and oil burning sources were the major anthropogenic ones. The study finally proposed some air quality control strategies to achieve the clean air quality in Suwon area.

• 한국멀티미디어학회논문지
• /
• 제13권8호
• /
• pp.1171-1182
• /
• 2010

본 논문에서는 특정 시점, 특정 장소의 대기 중에 발생하는 악취의 발생원을 추적하기 위한 악취분류 및 악취원 분석 방법을 제안한다. 이를 위해 악취원별 대표패턴의 생성이 필요하다. 이에 주요 악취원에서 측정한 67개의 악취를 악취 대표패턴으로 생성하였다. 또한, 여러 악취가 대기 중에서 섞였을 경우를 고려하여 2~3개의 악취들을 조합하여 복합 악취 대표패턴을 생성하였고, pseudo inverse method를 이용하여 악취에 대한 악취원들의 가중치를 계산하였다. 그 결과 해당 악취를 발생시킨 악취원들과 악취에 대한 기여도를 알아낼 수 있었다. 이러한 본 연구의 성과는 악취 관련 민원해결에 기여할 것으로 전망된다.