• 태양에너지
• /
• 제12권2호
• /
• pp.1-8
• /
• 1992

본 연구는 동계 외기온 데이타의 시각별 변동특성을 파악하기 위하여 연변동 성분 및 기간변동 성분을 제거한 일변동 성분의 매 시각별 외기온 데이타에 대해서 일교차의 발생요인에 대해서 분석하였다. 또한 동계시각별 외기온의 주파수 특성에 대해서 검토하였으며 외기온 데이타의 수식화의 가능성을 제시하였다.

• Smart Structures and Systems
• /
• 제19권2호
• /
• pp.137-149
• /
• 2017

Under the interference of the temperature effect, the alternation of cable force due to damages of a cable-stayed bridge could be difficult to distinguish. Considering the convenience and applicability in engineering practice, simple air or cable temperature measurements are adopted in the current study for the exclusion of temperature effect from the variation of cable force. Using the data collected from Ai-Lan Bridge located in central Taiwan, this work applies the ensemble empirical mode decomposition to process the time histories of cable force, air temperature, and cable temperature. It is evidently observed that the cable force and both types of temperature can all be categorized as the daily variation, long-term variation, and high-frequency noise in the order of decreasing weight. Moreover, the correlation analysis conducted for the decomposed variations of all these three quantities undoubtedly indicates that the daily and long-term variations with different time shifts have to be distinguished for accurately evaluating the temperature effect on the variation of cable force. Finally, consistent results in reducing the range of cable force variation after the elimination of temperature effect confirm the validity and stability of the developed method.

• 한국물환경학회지
• /
• 제27권6호
• /
• pp.914-925
• /
• 2011

The variation of streamflow is regarded as one of the most influential factors on the fluctuation of water quality in the stream. The characteristics of the variation should be taken into account in the plans for the management of Total Maximum Daily Loads (TMDLs). This study analysed and characterized spatial distribution and temporal variation of streamflow at each unit watershed in Guem-river basin. For the analysis of the distribution of streamflow, the type and the extent of the distribution were investigated for the unit watershed. For the analysis of the variation, short and long term changes of streamflow were examined. The result showed that most of the distributions were not log-normalized and the extent of variation tends to be greater at the unit watershed placed on the tributaries in the basin. A kind of margin could be granted to the unit watershed involving high variations so as to establish the water quality goal and load allotment more reasonably and effectively in view of whole waterbody.

• 한국환경보건학회지
• /
• 제47권1호
• /
• pp.36-44
• /
• 2021

Objectives: The study aims to examine the variation over roughly the past 10 years (from 2008 to 2018) in the estimated daily dietary Pb intake (Pb-D) based on the variations of daily intake amount and Pb content in respective food groups. The following factors were considered: (1) variation of estimated value of Pb-D, (2) Pb contents in each food group and (3) the most influential food group for dietary Pb intake. Methods: Estimated values of Pb-D were taken from food consumption by the food groups reported in the Korean National Health and Nutrition Survey and the Pb content of each food group as reported in 19 previous publications. Variation from 2008 to 2018 of Pb intake was calculated from daily intake amount and Pb content in each food group. Results: The survey showed that main Pb intake sources were the food groups 'meats and poultry' and 'fish and shellfish'. These food groups showed gradually increased Pb exposure from 2008 to 2018. Estimated daily Pb intake was 42.18 to 57.68 ㎍/day for men and 30.97 to 42.54 ㎍/day for women. Both men and women showed slightly increased dietary Pb intake from 2008 to 2018. The food groups 'meats and poultry' and 'fish and shellfish' proved the highest Pb intake food groups. Estimated Pb intake from 'meats and poultry' was 8.47 to 12.98 ㎍/day and that of 'fish and shellfish' was 5.63 to 10.10 ㎍/day. Conclusion: Over the past ten years, daily Pb intake has slightly increased in men and women. The food groups 'meats and poultry' and 'fish and shellfish' might be the main variation factors of Pb intake.

• 한국잠사곤충학회지
• /
• 제17권1호
• /
• pp.41-46
• /
• 1975

가잠견의 실용형질에 있어서 자웅간의 개체차이를 알기 위하여 잠 111$\times$잠 112의 19아구 (자견 843과, 웅견 806과)에 대하여 각 시양형질별로 견질의 개체변이, 동 아구내변이 및 동 아구간변이를 조사하였고, 정적 자웅 각 300과에 대한 일변화를 조사한 결과는 다음과 같다. 1. 견질의 변이 2. 견질의 일변화 전견중의 감모율은 용기의 초기보다 말기에 컸으며 그 경향은 자견보다 웅견이 더 컸다.

• 응용통계연구
• /
• 제36권5호
• /
• pp.457-471
• /
• 2023

월별 시계열은 일별 시계열의 월별 합이지만, 일별 시계열을 대체로 관측할 수 없어서 요일구성변동, 명절·공휴일변동 등 달력변동을 가상적으로 가정한 가변수를 포함한 RegARIMIA 모형을 이용하여 추정하고 있다. 일별 시계열을 관측할 수 있다면 요일구성변동, 명절·공휴일변동 등 달력변동을 일별 시계열을 바탕으로 추정할 수 있고 이를 이용하여 월별 시계열의 계절조정을 개선할 수 있다. 이 논문에서는 일별 시계열의 달력변동 추정을 이용하여 월별 시계열의 계절조정을 개선하는 방법을 제안하고, 이 방법을 적용하여 3개의 월별 시계열을 계절조정하고 기존의 X-13ARIMA-SEATS를 이용한 계절조정과 비교하였다.

• 한국산업보건학회지
• /
• 제29권4호
• /
• pp.488-499
• /
• 2019

Objectives: This study was conducted to identify the characterization of organics solvent exposure among painting workers in the shipbuilding painting process, especially for their daily variations(within worker variance). Methods: Charcoal passive dosimeters were worn throughout each work shift for 20 days for five painting workers from October 19 to November 26, 2015. A total of 100 samples were collected, analyzed and compared with statutory workplace environmental measurements. Results: The geometric mean(GM) and geometric standard deviation(GSD) of mixed organic solvent(six substances) exposure index(EI) for the 100 samples were 0.42 and 4.42 respectively. The median and range of GSD for within worker EI representing five workers' daily EI variation is 3.72 and 2.63 ~ 5.20, respectively, which is classified as a very large variation(GSD>3). We were able to divide the painting process into two similar exposure groups(SEGs), Touch-up and Spray. Spray painting workers were much more exposed to organic solvent than Touch-up painting workers(GM=0.71 vs. 0.19), but less variably (GSD=3.64 vs. 4.10). xylene is the substance to which the workers were most exposed(GM=16.19 ppm, GSD=4.36), and the exposure characteristics of six substances including xylene is similar to those of EI. Conclusions: The daily variation of organic solvent exposure in the shipbuilding painting process is so high that statutory Assessment of Reliability of Work Environment Monitoring needs to be conducted with statistically sufficient number of samples and evidence.

• 한국물환경학회지
• /
• 제28권3호
• /
• pp.426-435
• /
• 2012

The variation of stream flow is the one of the most important factors which influence on that of water quality in the unit watershed. The target water quality goal is established and permissible load is allotted in the base of the standard flow condition along with its water quality for the management of Total Maximum Daily Loads (TMDLs). A standard flow selected could cause problems in the load allotment if it was not properly arranged. This study reviewed the acquisition of water quality data, the self-variation and the retainability in water quality on the specific flow conditions. This study also proposed the median and the adjusted average flow condition out of general flow conditions as alternative standard flow conditions. It is considered that the alternatives can make the water quality data easily acquired and the water quality representativeness more enhanced on the standard flow conditions.

• 한국초지조사료학회지
• /
• 제8권3호
• /
• pp.68-76
• /
• 1988

The variation of rumination response in steers fed a same amount of orcharugrass hay was investigated. With three steers (6, 12, 24 months) of the Japanese Black Breed, rumination behaviour was measured continuously during a 5 days period by masseter EMG telemetry system. The results are summarized as follows: 1. The average daily rumination time of respective animals were 438,447 and 433 min. with small daily variation both within and among animal. But the rumination time per DM kg of hay consumed varied from 66 to 138 min., and calf spent longer than older calf. 2. Actural chewing time showed small variation, and percentage of actural chewing time spent in rumination time was from 88 to 93% on individual average. 3. The daily number of chewing in rumination was approximately 25,000 to 30,000 with large individual differences. The chews per DM kg intake varied from 3,800 to 9,600, and calf chewed more than older calf. 4. The average rate of chewing per 100 sec. (chewing speed), there was a large difference between animals i.e. 104, 114, 131 respectively, but very little variance between days in individual. 5. No relation between day to day variations in eating time and rumination behavior, but significantly positive correlation was observed in the relation among rumination time, chewing time, No. of boluses and No. of chews. 6. Active time of day in rumination altered considerably day to day, but variation in the amount of rumination per day as expressed by the rumination time was relatively small.

• 한국자원식물학회:학술대회논문집
• /
• 한국자원식물학회 2000년도 춘계임시총회 및 학술발표대회
• /
• pp.26-33
• /
• 2000

This study was conducted to investigate the relationships between yearly variations of elimatic elements and yearly variations of productivity in potato. In addition, correlation coefficients among yield and yield components were estimated. The data of yield and yield components were investigated for 9 years from 1987 to 1995. The meteorological data what gathered at the Goheung Weather Station for the same period of crop growing season were used to find out the relationships between climatic elements and crop productivity. Yearly variation of the daily minimum temperature in March and April were large with coefficients of variation (C.V.) of 126.0%, 368%, respectively, but the variation of the daily mean and maximum temperature in May and June were relative small. Stem length and number of stem show more C.V. of 9.3%, 14.3%, respectively, but the variation of the yield was relative small with 3.7%. Correlation coefficients between the amount of precipitation in April and yield, yield and daily mean temperature in June were negatively significant at the level of 5, 1 %, respectively. Correlation coefficients between the growth habits and yield are positively significant at the level of 5, 1 %, respectively. Simple linear regression equations by the least square method are estimated for stem length (Yl) and the precipitation in April(X) as Y,=82.47-0.11x (R2=0.3959), and for yield(Y2) and the precipitation in April(X) as Y,=2003.61-0.94X (R2=0.5418).