심벌 트랜스듀서의 종류별 음향 특성 비교 분석

최유지,심하영,노용래,Choi, Youji,Shim, Hayeong,Roh, Yongrae 한국음향학회 2019 韓國音響學會誌 Vol.38 No.3

수중 탐지용으로 사용되는 심벌 트랜스듀서에는 여러 가지 종류가 연구되어져 왔는데, 대표적인 종류로 Moonie 트랜스듀서, 컨벡스 심벌 트랜스듀서, 그리고 컨케이브 심벌 트랜스듀서 등이 있다. 본 연구에서는 수중 광대역 프로젝터용으로 이들 세 종류의 트랜스듀서의 특성을 분석하고 비교하였다. 트랜스듀서의 구조 변수들이 각 트랜스듀서의 음향 특성에 미치는 영향을 분석하고 이를 바탕으로 각 트랜스듀서 종류가 특정 중심주파수를 가지면서 대역폭이 최대가 되는 구조를 도출하였다. 최적화된 구조를 가지는 트랜스듀서들의 성능을 비교한 결과, 컨벡스 심벌 트랜스듀서가 광대역과 고출력, 두 측면에서 모두 가장 우수하다는 것을 확인하였다. Several types of cymbal transducers used for underwater detection have been studied. Representative types are Moonie, convex cymbal, and concave cymbal transducers. In this study, we analyzed the characteristics of these three types of transducers for underwater broadband projectors and compared them together. First, the influence of structural variables on the acoustic characteristics of the transducers was analyzed. Based on this, we derived the structure of each transducer type to have a specific center frequency and the maximum bandwidth. As a result of comparing the performance of the optimized transducers, the convex cymbal transducer turned out to be best in terms of both broad bandwidth and high power.

현대 일본 도시 집합주택에 나타난 공간구성 특성에 관한 연구

최유지(Choi, Yu-Ji),김문덕(Kim, Moon-Duck) 한국실내디자인학회 2008 한국실내디자인학회 학술대회논문집 Vol.10 No.1

웹검색 트래픽 정보를 활용한 유커 인바운드 여행 수요 예측 모형 및 유커마이닝 시스템 개발

최유지(Choi, Youji),박도형(Park, Do-Hyung) 한국지능정보시스템학회 2017 지능정보연구 Vol.23 No.3

As social data become into the spotlight, mainstream web search engines provide data indicate how many people searched specific keyword: Web Search Traffic data. Web search traffic information is collection of each crowd that search for specific keyword. In a various area, web search traffic can be used as one of useful variables that represent the attention of common users on specific interests. A lot of studies uses web search traffic data to nowcast or forecast social phenomenon such as epidemic prediction, consumer pattern analysis, product life cycle, financial invest modeling and so on. Also web search traffic data have begun to be applied to predict tourist inbound. Proper demand prediction is needed because tourism is high value-added industry as increasing employment and foreign exchange. Among those tourists, especially Chinese tourists: Youke is continuously growing nowadays, Youke has been largest tourist inbound of Korea tourism for many years and tourism profits per one Youke as well. It is important that research into proper demand prediction approaches of Youke in both public and private sector. Accurate tourism demands prediction is important to efficient decision making in a limited resource. This study suggests improved model that reflects latest issue of society by presented the attention from group of individual. Trip abroad is generally high-involvement activity so that potential tourists likely deep into searching for information about their own trip. Web search traffic data presents tourists attention in the process of preparation their journey instantaneous and dynamic way. So that this study attempted select key words that potential Chinese tourists likely searched out internet. Baidu-Chinese biggest web search engine that share over 80%- provides users with accessing to web search traffic data. Qualitative interview with potential tourists helps us to understand the information search behavior before a trip and identify the keywords for this study. Selected key words of web search traffic are categorized by how much directly related to “Korean Tourism” in a three levels. Classifying categories helps to find out which keyword can explain Youke inbound demands from close one to far one as distance of category. Web search traffic data of each key words gathered by web crawler developed to crawling web search data onto Baidu Index. Using automatically gathered variable data, linear model is designed by multiple regression analysis for suitable for operational application of decision and policy making because of easiness to explanation about variables effective relationship. After regression linear models have composed, comparing with model composed traditional variables and model additional input web search traffic data variables to traditional model has conducted by significance and R squared. after comparing performance of models, final model is composed. Final regression model has improved explanation and advantage of real-time immediacy and convenience than traditional model. Furthermore, this study demonstrates system intuitively visualized to general use -Youke Mining solution has several functions of tourist decision making including embed final regression model. Youke Mining solution has algorithm based on data science and well-designed simple interface. In the end this research suggests three significant meanings on theoretical, practical and political aspects. Theoretically, Youke Mining system and the model in this research are the first step on the Youke inbound prediction using interactive and instant variable: web search traffic information represents tourists attention while prepare their trip. Baidu web search traffic data has more than 80% of web search engine market. Practically, Baidu data could represent attention of the potential tourists who prepare their own tour as real-time. Finally, in political way, designed Chinese tourist demands prediction model based on web search traffi

웹검색트래픽 정보를 활용한 투자모형 개발: KOSPI지수를 중심으로

김범수 ( Beom Su Kim ),최유지 ( You Ji Choi ),박도형 ( Do Hyung Park ) (주)엘지씨엔에스(구 LGCNS 엔트루정보기술연구소) 2015 Entrue Journal of Information Technology Vol.14 No.3

빅데이터 관련 기술은 기존의 투자모형 연구가 고려하지 못했던 유용한 정보들을 제공하고 있다. 대표적으로 트위터(Twitter)를 이용한 SNS 데이터나 인터넷 뉴스 기사 분석을 통한 주가예측 연구 등이 있다. 이들 연구는 가격이나 재무정보 등에 한정되어 있던 투자연구에서 벗어나 비정형적인 정보를 이용한다는 특징이 있다. 본 연구에서는 이러한 빅데이터 중에서도 그 동안 제대로 조명되지 않았던 웹검색트래픽(Web Search Traffic)을 이용하여 투자모형을 수립해 보고자 하였다. 가설 검증 결과, 웹검색트래픽과 거래량 간에는 유의한 양의 상관관계를 나타내었으며 주가의 변동치와는 유의한 음의 상관관계를 나타내었다. 또한 검증 결과를 기반으로 몇 가지 투자전략을 모의거래(Simulation)해 본 결과 웹검색트래픽의 변동에 대해 한 주의 시차를 두고 투자한 전략이 벤치마크 전략보다 우수하였음을 알게 되었다. The evolution of big data analysis technology provides us with useful information which couldn’t obtain based on traditional in-vestment model. Recent studies focusing on SNS data (e.g. Twitter), news data, or community postings showed the usefulness of this approach for financial investment decision-making. They are differentiated from traditional studies on financial investment in terms of the utilization of unstructured data to show investors’ behavior such as mental states, market reaction, or attention. This study proposes the investment model based on Web Search Traffic which has rarely been used for investment model until now. The infor-mation of Web Search Traffic is able to play a role to show the investor’s attention on stock market, which can be a proxy measure for the attention or focus. Firstly, this study suggests and tests the four hypotheses on the relationship between KOSPI index and Web Search Traffic using ARIMA analysis with independent variables. It revealed the statistically significant relationship between Web Search Traffic and the volume, value and range of KOSPI index. Finally, we develop the several investment strategies using Web Search Traffic and validated the excellence in terms of the rate of return, compared with benchmark strategies.

패스틴^� 첨가가 단백질 분해율과 반추위 발효 및 영양소 소화율에 미치는 영향

최유지,최낙진,박성호,송재용,엄재상,고종렬,하종규 한국동물자원과학회 2002 한국축산학회지 Vol.44 No.5

본 시험은 패스틴^R을 첨가하였을 때, in vitro 상에서 단백질 fraction과 분해율에 미치는 영향과, in vivo 상에서 반추위 성상, 미생물 군집, 암모니아태 질소 농도 및 영양소 소화율에 미치는 영향을 규명하고자 실시하였다. In vitro 실험에서는 1㎜로 분쇄된 대두박을 기질로 하여 패스틴^R(㈜은진인터내셔날)을 첨가하여 borate-phosphate buffer와 중성세제에서의 조단백질 분해율을 측정하였으며, exogenous enzyme (Streptomyces griseus 유래 protease)를 이용하여 39℃에서 0, 2, 4, 8, 12, 48 시간동안 배양 후 조단백질 분해율을 측정하였다. 반추위 발효성상과 영양소 소화율은 반추위 fistula가 부착된 평균체중 300㎏의 홀스타인 수소 4두를 이용하여 무첨가구, 패스틴^R 첨가구의 두 개 처리구에 2마리씩 4마리를 배치하여 측정하였다. Buffer Soluble Protein fraction은 패스틴^R 첨가 수준별로 차이가 없었으나, 무첨가구에 비해 패스틴^R 첨가구에서 감소하는 경향을 보였다. 단백질 분해율은 배양 0 시간대에서 4시간대까지는 처리구간 유의성이 없었지만, 12 h과 48 h에서는 패스틴^R 첨가로 시험구에서 감소되었다. 용해 단백질 분해율 “a”는 패스틴^R 시험구에서 경미하게 높은 수치를 나타내었지만, 소화 가능한 단백질 분해율 “a+b”는 패스틴^R 시험구에서 낮은 경향을 보였다. 패스틴^R 첨가로 pH와 NH_3-N 농도는 증가하는 경향이었으며 휘발성지방산, 미생물 수 및 enzyme activity는 감소하였고 영양소 소화율은 높았으나 유의적인 차이는 없었다. This study, including two in vitro experiments and an invivo experiment were conducted to evaluate effects of Passtein^R on crude protein degradability, ruminal fermentation characteristics and nutrient digestibility. In in vitro experiment protein degradability was examined using borate-phosphate buffer and neutral detergent, and using protease from Stroptomyces griseus at 39℃ for 0, 2, 4, 8, 12 and 48 h. In addition, an in vivo experiment was conducted in a switch back design and ruminal fermentation and nutrient digestibility were determined. Four ruminal-fistulated Holstein cows weighing 300㎏ in mean body weight randomly allotted to 2 treatments (control and Passtein^R supplementation). Although there was no significant difference on protein fraction between treatments, it appears that Passtein^R supplementation decreased buffer soluble protein fraction compared to control. Protein degradability was not affected by Passtein^R from 0 h to 4 h, but decreased at 12 h and 48 h compared to control. Degradation of immediately degradable fraction was higher in Passtein^R treatment, but degradation of fermentable fraction was lower in Passtein^R treatment compared to control. The pH and NH_3-N concentration tended to increase in Passtein^R treatment, but VFA production, microbial counts and enzyme activity tended to decrease in Passtein^R treatment compared to control. In addition, nutrient digestibility in the total tract tended to increase in Passtein^R treatment compared to control.

유카 추출물 첨가가 In Vitro 반추위 미생물 발효에 미치는 영향

황일환,이상석,Chalermglin, Piya,홍승희,최유지,하종규 한국동물자원과학회 2001 한국축산학회지 Vol.43 No.5

An in vitro experiment with mixed ruminal microorganism was conducted to investigate the effects of Yucca extract(YE) and substrate on medium pH, gas production, number of bacteria and protozoa, enzymatic activities, and VFA at different incubation times. The factorial design consisted of 2 main factors(substrates: 1㎜ ground straw and 4mm cracked corn) with 3 minor factors(YE levels: 0, 30 and 90 ㎎) in 5 incubation times(0, 12, 24, 48 and 72 hr). All incubations were repeated three times. The supplementation of YE generally reduced gas production, ammonia concentration, the number of bacteria and protozoa and DM digestion with minor effect on medium pH and VFA production. Compared to rice straw as a substrate, corn produced more gas, decreased medium pH. increased bacterial numbers, and was more digestible. Current results indicate that YE has direct and indirect effect on the types and numbers of ruminal microbes and hence on ruminal fermentation