• Korean Journal of Remote Sensing
• /
• v.26 no.6
• /
• pp.665-673
• /
• 2010

The role of remote sensing in phenological studies is increasingly regarded as a key in understanding large area seasonal phenomena. This paper describes the application of Moderate Resolution Imaging Spectroradiometer (MODIS) time series data for vegetation classification using seasonal variation patterns. The vegetation seasonal variation phase of Seoul and provinces in Korea was inferred using 8 day composite MODIS NDVI (Normalized Difference Vegetation Index) dataset of 2006. The seasonal vegetation classification approach is performed with reclassification of 4 categories as urban, crop land, broad-leaf and needle-leaf forest area. The BISE (Best Index Slope Extraction) filtering algorithm was applied for a smoothing processing of MODIS NDVI time series data and fuzzy classification method was used for vegetation classification. The overall accuracy of classification was 77.5% and the kappa coefficient was 0.61%, thus suggesting overall high classification accuracy.

• Journal of agricultural medicine and community health
• /
• v.26 no.1
• /
• pp.115-119
• /
• 2001

The effect of seasonal variation on social statistic data is important. But in health subcenter in rural areas the effect has not been well known. To determine the seasonal index of medical needs in rural communities, the monthly number of patients were analyzed from Jan. 1994 to Dec. 2000. Seasonal index were calculated using 12 months moving averages and median value of each data. The number of patients excluding common cold were analyzed by same method. The seasonal index from Jan. to Dec. were 0.96, 1.08, 1.23, 0.83, 0.82, 0.75, 1.01, 0.99, 1.02, 1.05, 1.13, 1.13. The seasonal index of patients excluding those with common cold were 0.94, 0.90, 1.42, 0.94, 0.91, 0.77, 1.13, 0.92, 0.84, 1.07, 1.10, 1.16. In a rural area, medical needs are decreased on spring and early summer and increase in winter, and that are the influence of rural area.

• Journal of Korean Society on Water Environment
• /
• v.28 no.1
• /
• pp.78-83
• /
• 2012

Man-made reservoirs over 95% in Korea are shallower than 10 meters in depth, which is apt to cause eutrophication. This study has characterized long-term trends in water quality factors for the selected six reservoir points in the Kum River watersheds, and then estimated the seasonal trophic state index for each reservoir. The reservoir trophic state was evaluated at four trophic levels using the Korean trophic state index, TSIKO. It is observed from seasonal results for six reservoirs that the highest value of the trophic state index is estimated in summer while the trophic state index value is low in spring and winter seasons. Especially, the Boryeong Lake has a relatively lower trophic state index since this reservoir has been managed properly for water withdrawal and irrigation. It is expected that the seasonal trophic state index resulted from this study can contribute toward long-term water quality improvement plans for reservoirs.

• Advances in environmental research
• /
• v.4 no.2
• /
• pp.83-104
• /
• 2015

Air Quality Index (AQI) is a pointer to broadcast short term air quality. This paper presents one day ahead AQI forecasting on seasonal basis for three major cities in Maharashtra State, India by using Artificial Neural Networks (ANN) and Genetic Programming (GP). The meteorological observations & previous AQI from 2005-2008 are used to predict next day's AQI. It was observed that GP captures the phenomenon better than ANN and could also follow the peak values better than ANN. The overall performance of GP seems better as compared to ANN. Stochastic nature of the input parameters and the possibility of auto-correlation might have introduced time lag and subsequent errors in predictions. Spectral Analysis (SA) was used for characterization of the error introduced. Correlational dependency (serial dependency) was calculated for all 24 models prepared on seasonal basis. Particular lags (k) in all the models were removed by differencing the series, that is converting each i'th element of the series into its difference from the (i-k)"th element. New time series is generated for all seasonal models in synchronization with the original time line & evaluated using ANN and GP. The statistical analysis and comparison of GP and ANN models has been done. We have proposed a promising approach of use of GP coupled with SA for real time prediction of seasonal multicity AQI.

• Journal of Environmental Science International
• /
• v.19 no.4
• /
• pp.491-507
• /
• 2010

This study focuses on the fauna, seasonal prevalence and altitudinal distribution of the flies from March to November, 2008 in Mt. Hallasan, Jejudo Island, Korea. The fauna of flies was 39 species belonging to 5 Families which consist of 12 Calliphoridae, 19 Muscidae, 5 Sarcophagidae, 1 Dryomyzidae 1, Scathophagidae and 1 Anthomyiidae. The total number of flies collected was 21,605 with sex ratio of 57.98% in Mt. Halla. The ratio is higher than that of the residential area and other mountain survey sites. The average number of per trap individuals collected on the trapping day is 267, which is similar with the average of Mts. Jiryong, Juwang, Palgong and Gumo. The five dominant species showed a distinctive seasonal prevalence of 92.6% of the total flies: Chrysomyia pinguis (34.2%), Calliphora lata (25.3%), Hydrotaea dentipes(23.1%), Fannia scalaris (5.1%), and Lucilia caesar (4.9%). The seasonal prevalence of the flies was from the beginning of March to the end of November, and the highest peak time of the whole flies, males and females were different respectively. In the similarity index of the flies collected in different altitude, that of between 1,000 meters and 1,500 meters was the highest among the indices of 500 meters and above 1,000 meters. The index at each altitude was above 80% because of the same area. The diversity index of fly species was between 0.00 and 0.88 through altitudinal traps monthly. The highest index in Trap 1 was 0.88 in October, in Trap 2, 0.82 in July and in Trap 3, 0.63 in July. The diversity above 1,000 meters was most various in July. The five dominant species of C. pinguis, C. lata, H dentipes, F. scalaris, and L. caesar showed distinctive seasonal prevalence, relative abundance and altitudinal distribution respectively.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.50 no.4
• /
• pp.455-466
• /
• 2014

Seasonal variations in species composition of catches were explored using seasonal samples caught by shrimp beam trawl in the Geum river estuary in 2011. During the study period, total catches were collected 91 species as fish 47 species, crustacean 28 species, mollusca 4 species, gastropoda 5 species, shellfish 3 species and others 4 species. The dominant species were Exopalaemon carinicauda, Eriocheir leptognathus, Palaemon gravieri, Mugil cephalus, Acanthogobius hasta, Cynoglossus joyneri, Pennahia argentata and Coilia nasus. The amount of species in spring and summer was higher than in autumn. The diversity index (H') was 0.43~0.96, evenness index (EI) was 0.14~0.25, and richness index (RI) was 1.54~4.25. Using cluster analysis 91 species were divided into 4 groups. Group I appeared mainly in spring and summer. Group II appeared only in summer. Group III appeared in winter and spring, and Group IV in spring and autumn.

• Journal of The Korean Astronomical Society
• /
• v.36 no.spc1
• /
• pp.93-99
• /
• 2003

Various attempts have been made to explain the: pronounced seasonal and universal time (UT) variations of geomagnetic indices. As one of such attempts, we analyze the hourly-averaged auroral electroject indices obtained during the past 20 years. The AU and AL indices maximize during summer and equinoctial months, respectively. By normalizing the contribution of the solar conductivity enhancement to the AU index, or to the eastward electrojet, it is found that the AU also follows the same semiannual variation pattern of the AL index, suggesting that the electric field is the main modulator of the semiannual magnetic variation. The fact that the variation pattern of the yearly-mean AU index follows the mirror image of the AL index provides another indication that the electric field is the main modulator of magnetic disturbance. The pronounced UT variations of the auroral electrojet indices are also noted. To determine the magnetic activity dependence, the probability of recording a given activity level of AU and AL during each UT is examined. The UT variation of the AL index, thus obtained, shows a maximum at around 1200-1800 UT and a minimum around 0000-0800 UT particularly during winter. It is closely associated with the rotation of the geomagnetic pole around the rotational axis, which results in the change of the solar-originated ionospheric conductivity distribution over the polar region. On the other hand the UT variation is prominent during disturbed periods, indicating that the latitudinal mismatch between the AE stations and the auroral electrojet belt is responsible for it. Although not as prominent as the AL index, the probability distribution of the AU also shows two UT peaks. We confirm that the Dst index shows more prominent seasonal variation than the AE indices. However, the UT variation of the Dst index is only noticeable during the main phase of a magnetic storm. It is a combined result of the uneven distribution of the Dst stations and frequent developments of the partial ring current and substorm wedge current preferentially during the main phase.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.37 no.E
• /
• pp.72-78
• /
• 1995

To support some knowledge in planning irrigation system, short or long-term irrigation scheduling or determining irrigation reservoir capacity, it is necessary to estimate peak irrigation requirements and seasonal distribution of water demands for various return periods. In this paper Dry Day Index and Probable Evapotranspiration were evaluated to decide seasonal consumptive use of paddy rice for a design year using several decades' daily rainfall data and 5 years'('82~'86) actual evapotranspiration data, respectively. To obtain Dry Day Index that is defined as the number of probable dry days for a given period, Slade unsymmetrical distribution function was adopted. Dry Day Index was analysed for 5 and 10-day intervals. Each of them was evaluated with return periods of 1, 3, 5, 10 and 20 year. Their singnificance was tested by X$^2$ method. Based on these values, the Probable Evaportanspiration, that is the average daily ET both in dry days and rainy days during a given period, was estimated. Crop coefficient was also determined by the modified Penman equation proposed by Doorenbos & Pruitt.

• Journal of Marine Bioscience and Biotechnology
• /
• v.13 no.1
• /
• pp.58-65
• /
• 2021

In 2012, fishes caught by three-side fyke net in the coastal waters of Jedo were assessed for species composition and seasonal fluctuation in their abundance. The fish were caught at two research stations (St.) and were found to comprise 53 species, 39 families, and 9 orders. The dominant species were Takifugu niphobles, Lateolabrax maculatus, and Acanthopagrus schlegelii. To gain a measure of their biodiversity, all the species were assessed for their number, richness, diversity, evenness, and dominance. The highest and lowest number of total caught fish individuals was recorded in summer and winter, respectively. The diversity index was the highest in summer and lowest in winter. The evenness index was the highest in summer and lowest in spring. The richness index was highest in summer and lowest in winter. Furthermore, the dominance index was highest in spring and lowest in autumn.

• Korean Journal of Community Nutrition
• /
• v.6 no.4
• /
• pp.592-603
• /
• 2001

Seasonal variations of nutrient intake ware evaluated through a 3-day dietary records in 196 Korean adolescents(86 males, 108 females) aged 13 - 15 years and living in urban and rural areas of Chungnam. The seasonal differences of nutrient intake were tested by repealed measure ANOVA. Comparing nutrient intakes among flour seasons using repealed measure ANOVA, mean values of daily intakes were higher in winter and autumn for most nutrients, and were the lowest in summer in the urban areas and in spring in rural areas. Girls recieved the largest amount of nutrients, except Ca and vitamin $B_12$, in winter and the lowest amount in summer, while in boys significant differences were not observed among the four seasons for meet nutrients, except fats, Mg, and vitamin E. Interestingly, the seasonal differences for many nutrients were more evident in rural areas than in urban areas. Vitamin A intake in urban areas was higher in winter and spring, while in rural oreas, in summer. Mean values of daily intakes as a percent of the RDA throughout the year in boys and girls ware 82.2% and 84.2% for energy and 88.9% and 82.7% for protein, respectively. Ca and vitamin A intakes were as low as 32.4% and 24.2% of the RDA in boys and 39.7% and 30.6% in girls. Intakes of Fe, Zn, folic acid and vitamin B$_{12}$ ranged from 40 - 60% of the RDA. The nutrients which showed the largest seasonal difference in the percent of RDA were vitamin E in boys and vitamin C, vitamin E, and Fe in girls. The index of nutritional quality(INQ) for Fe was significantly lower in autumn in both genders. The INQ for vitamin C in girls of both areas was much higher in winter. Annual mean adequacy ratio(MAR), an index of overall nutritional quality, ranged from 0.57 - 0.69, which was higher in winter than in other seasons. Conclusively, nutrient intakes of Korean adolescents showed seasonal variations, particularly in girls and in rural area. Thus, seasonal variations should be considered in the assessing nutritional status, particularly ill the rural areas of Korea.a.