자동차 건조 공정 에너지 예측 모형을 위한 공조기 온도 시계열 데이터의 상관관계 분석

이창용(Chang-Yong Lee),송근수(Gensoo Song),김진호(Jinho Kim) 한국산업경영시스템학회 2014 한국산업경영시스템학회지 Vol.37 No.2

In this paper, we investigate the statistical correlation of the time series for temperature measured at the heat box in the automobile drying process. We show, in terms of the sample variance, that a significant non-linear correlation exists in the time series that consist of absolute temperature changes. To investigate further the non-linear correlation, we utilize the volatility, an important concept in the financial market, and induce volatility time series from absolute temperature changes. We analyze the time series of volatilities in terms of the de-trended fluctuation analysis (DFA), a method especially suitable for testing the long-range correlation of non-stationary data, from the correlation perspective. We uncover that the volatility exhibits a long-range correlation regardless of the window size. We also analyze the cross correlation between two (inlet and outlet) volatility time series to characterize any correlation between the two, and disclose the dependence of the correlation strength on the time lag. These results can contribute as important factors to the modeling of forecasting and management of the heat box's temperature.

광역 네트워크 트래픽의 장거리 상관관계와 1/f 노이즈

이창용,Lee, Chang-Yong 한국정보과학회 2010 정보과학회논문지 : 정보통신 Vol.37 No.1

본 논문에서는 네트워크 트래픽의 수동적 측정치 분석을 통해 잘 알려진 장거리 상관관계가 광역 네트워크의 능동적 측정치에도 존재하는지 여부를 관련 분석법을 통하여 검정하고자 한다. 이를 위하여 PingER 프로젝트를 통하여 측정된 광역 네트워크 트래픽의 대표적인 능동적 측정치인 RTT(Round Trip Time)와 RTT의 변동성 시계열 데이터에 대하여 분석을 수행하였다. RTT 시계열 데이터는 장거리 상관관계 혹은 1/f 노이즈의 특성을 보였으며, RTT의 고차원 변화량으로 정의된 변동성은 로그정규분포를 따르며 변동성에 대한 장거리 상관관계는 고려하는 시간 간격이 짧은 경우 장거리 상관관계를 보이고, 시간 간격이 긴 경우에는 장거리 상관관계 혹은 1/f 노이즈를 따름을 밝혔다. 본 연구를 통해 볼 때 장거리 상관관계는 비단 패킷 도착의 시간 간격 등과 같은 수동적 측정뿐만 아니라 RTT와 같은 능동적 측정에서도 나타나는 특징이며, 특히 능동적 측정에는 수동적 측정에는 잘 나타나지 않는 1/f 노이즈 특성이 존재함을 밝혔다. In this paper, we examine a long-range dependence in an active measurement of a network traffic which has been a well known characteristic from analyses of a passive network traffic measurement. To this end, we utilize RTT(Round Trip Time), which is a typical active measurement measured by PingER project, and perform a relevant analysis to a time series of both RTT and its volatilities. The RTT time series exhibits a long-range dependence or a 1/f noise. The volatilities, defined as a higher-order variation, follow a log-normal distribution. Furthermore, volatilities show a long-range dependence in relatively short time intervals, and a long-range dependence and/or 1/f noise in long time intervals. From this study, we find that the long-range dependence is a characteristic of not only a passive traffic measurement but also an active measurement of network traffic such as RTT. From these findings, we can infer that the long-range dependence is a characteristic of network traffic independent of a type of measurements. In particular, an active measurement exhibits a 1/f noise which cannot be usually found in a passive measurement.

산업부문에서의 에너지 관리대책

이창용,Lee, Chang-Yong 대한석유협회 1981 석유와 에너지 Vol.1981 No.10

확률·통계적 건설공정 이산화탄소 배출량 추정 방법론

이창용,곽한성,이동은,Yi, Chang-Yong,Gwak, Han-Seong,Lee, Dong-Eun 大韓建築學會 2014 大韓建築學會論文集 : 構造系 Vol.30 No.8

Reducing greenhouse gas(GHG) emissions is a worldwide concern. Low carbon construction is an important operation management goal. Construction resources(i.e., equipment and laborer) are major contributors to producing GHG, and they are the main target for achieving low carbon construction. The amount of Carbon emissions varies depending on the operating conditions. This paper introduces a method which measures the variability of carbon emissions amounts. First, it allows creating construction operation models of which the level of detail is breakdown into the work task level. It makes use of the equipments' hourly fuel consumption and laborers' hourly respiration rate. Second, the method implements sensitivity analysis along with ranges of resources that are allocated in an operation model. It facilitates to find the optimal resource combination using the operation performances such as the amount of emissions, operation completion time, operation completion cost, and productivity. Third, it identifies the best fit probability distribution functions of performance criteria given a certain resource combination. It allows project manager to query the chance to complete the operation within limitations of multiple performance criteria specified by the system users.

우주항법을 위한 GPS/SDINS/ST 결합 알고리듬

이창용,조겸래,이대우,조윤철,Yi, Chang-Yong,Cho, Kyeum-Rae,Lee, Dae-Woo,Cho, Yun-Cheol 한국항공운항학회 2016 한국항공운항학회지 Vol.24 No.2

A GPS/SDINS/ST(Star Tracker) integrated sensor algorithm is more robust than the GPS/SDINS and the ST/SDINS systems on exploration of other planets. Most of the advanced studies shown that GPS/SDINS/ST integrated sensor with centralized Kalman filter was more accurate than those 2 integrated systems. The system, however, consist of a single filter, it is vulnerable to defects on failed data. To improve the problem, we work out a study using federated Kalman filter(No-Reset mode) and centralized Kalman filter with adaptive measurement fusion which known as robustness on fault. The simulation results show that the debasing influences are reduced and the computation is enable at least 100Hz. Further researches that the initial calibration in accordance with observability and applying the exploration trajectory are needed.

철강 재료의 마찰 교반 점 용접

이창용,최돈현,연윤모,서원찬,정승부,Lee, Chang-Yong,Choi, Don-Hyun,Yeon, Yun-Mo,Seo, Won-Chan,Jung, Seung-Boo 대한용접접합학회 2008 대한용접·접합학회지 Vol.26 No.6

환원 , 산화처리한 동함유 모더나이트 결정의 열화 특성

이창용(Chang Yong Lee),최고열(Ko Yeol Choi) 한국공업화학회 2002 공업화학 Vol.13 No.6

수소형 모더나이트와 탈알루미늄 모더나이트에 여러 함량의 동을 수용액 함침으로 담지한 후 500 ℃ 또는 750 ℃에서 수소/산소로 환원ㆍ산화처리하여 CuO/HM과 CuO/DM 시료를 제조하였다. XRD와 SEM 분석을 통하여 이들 시료의 결정 상태에 대하여 연구하였다. 500 ℃에서 환원ㆍ산화처리한 시료에서는 모더나이트의 결정열화가 나타나지 않았다. 750 ℃에서 환원ㆍ산화처리한 CuO/HM 시료에서는 모더나이트 동함량 변화에 따라 단위격자가 수축하면서 모더나이트의 결정열화가 심화하였다. 750 ℃에서 환원처리시 모든 축에서 수축한 CuO/DM의 단위 격자는 같은 온도에서 산화처리 함으로서 b축으로만 증가하였다. 따라서 750 ℃에서 환원ㆍ산화처리한 CuO/DM은 한 축 방향으로 결정열화가 일어난다는 것을 알 수 있었다. Hydrogen mordenite and aluminum-deficient mordenite with various copper content were prepared by impregnation in aqueous solution, and they were treated with H_2/O_2 redox cycle at 500 or 750 ℃. XRD patterns and SEM were used to study the crystal phase and morphology of both CuO/HM and CuO/DM, respectively. The deterioration of mordenite crystals was not evident in the CuO/HM and CuO/DM, which were treated with H_2/O_2 redox cycle at 500 ℃. However, when the CuO/HM that was treated with H_2/O_2 redox cycle at 750 ℃, the deterioration of mordenite crystals increased in proportion to the shrinkage of crystal unit cell that depended on its copper content. The unit cell of CuO/DM crystal that shrunk in all axes through the reduction treatment at 750 ℃, expanded only in b-axis when the oxidation took place at the same temperature. Therefore, it was found that the mordenite crystal of CuO/DM deteriorated in the direction of one axis by treating with H_2/O_2 redox cycle at 750 ℃.

현대 식품시스템과 녹색환경

이창용(Chang Yong Lee) 한국식품과학회 2010 식품과학과 산업 Vol.43 No.3

Nitrogen Compounds in Vegetable Foods

Chang Yong Lee(李彰容) 한국식품과학회 1972 한국식품과학회지 Vol.4 No.1

폴리페놀 함량과 항산화력에 따른 로즈마리의 최적 추출조건 확립

이창용(Chang-Yong Lee),김기명(Ki-Myeong Kim),손홍석(Hong-Seok Son) 한국식품과학회 2013 한국식품과학회지 Vol.45 No.4

본 연구에서는 로즈마리의 항산화 물질을 최대로 추출할 수 있는 최적의 추출 조건을 확립하였다. 열수 추출의 경우에는 90℃, 30분 추출할 경우 항산화력(IC<SUB>50</SUB> 값이 4.49 g DM/L)과 총 페놀함량(28.30 mg GAE/g DM)이 다른 온도와 시간보다 높은 수치를 나타내었다. 에탄올 추출의 경우에는 50%에탄올, 70℃, 10분의 경우가 항산화력(IC<SUB>50</SUB> 값이 2.60 g DM/L), 총 페놀함량(40.28 mg GAE/g DM)이 다른 농도와 온도, 시간보다 높은 결과를 나타내었다. 메탄올 추출 결과는 75% 메탄올, 60℃, 30분의 경우가 항산화력(IC<SUB>50</SUB> 값이 2.31 g DM/L), 총 페놀함량(57.22 GAE/g DM) 이 다른 농도와 온도, 시간보다 높은 수치를 나타내었다. We evaluated the effects of temperature, time, solvent type, and solvent concentration on the phenolic content and antioxidant activity of rosemary extracts. The antioxidant capacity of rosemary extracts was demonstrated by their ability to scavenge stable free radicals, and the phenolic content of the extracts was determined using the Folin Ciocalteu method. The highest values were obtained by water-based extraction at 90℃ for 30 min, a 75% methanol solution at 60℃ for 30 min, and a 50% ethanol solution at 70℃ for 10 min. The aqueous solution of 75% methanol, extraction temperature of 60℃, and extraction time of 30 min were the most efficient parameters for the extraction of polyphenols from dry rosemary.