• KSCE Journal of Civil and Environmental Engineering Research
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• v.44 no.4
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• pp.443-463
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• 2024

This study sought to improve the accuracy of precipitation prediction by utilizing monthly precipitation data for each region over the past 30 years. Using statistical models (ARIMA, SARIMA) and deep learning models (LSTM, GBM), we learned monthly precipitation data from 1983 to 2012 in Gangneung, Gwangju, Daegu, Daejeon, Busan, Seoul, Jeju, and Chuncheon. Based on this, monthly precipitation was predicted for 10 years from 2013 to 2022. As a result of the prediction, most models accurately predicted the precipitation trend, but showed a tendency to underpredict the actual precipitation. To solve these problems, appropriate models were selected for each region and season. The LSTM model showed suitable results in Gangneung, Gwangju, Daegu, Daejeon, Busan, Seoul, Jeju, and Chuncheon. When comparing forecasting power by season, the SARIMA model showed particularly suitable forecasting performance in winter in Gangneung, Gwangju, Daegu, Daejeon, Seoul, and Chuncheon. Additionally, the LSTM model showed higher performance than other models in the summer when precipitation is concentrated. In conclusion, closely analyzing regional and seasonal precipitation patterns and selecting the optimal prediction model based on this plays a critical role in increasing the accuracy of precipitation prediction.

• Korean Journal of Ecology and Environment
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• v.45 no.1
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• pp.42-51
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• 2012

This study investigated the characteristics of natural organic matter (NOM) with general water characteristics (pH, DO, electrical conductivity, BOD, COD, TN, TP, Chl-$a$, DOC, $UV_{254}$, SUVA) and the 3D fluorescence excitation-emission matrix (FEEM) in the Yeongsan River basin. FEEM was used to classify protein-like and fulvic & humiclike substances with fluorescence intensity in the matrix of excitation and emission wavelength. The concentration of BOD, COD, TN, electrical conductivity and DOC in the region of Gwangju city (Gwangju sewage treatment plant: GJS, Gwangjucheon: GJC, Gwangju 2: GJ2) was relatively higher than the upper reaches and lower reaches of the Yeongsan River basin. SUVA in most sites was lower than 3 L $mg^{-1}\;m^{-1}$ as the hydrophilic substances, except Damyang (DY) in the upper reaches of Yeongsan river was higher than 3 L $mg^{-1}\;m^{-1}$ as the hydrophobic substances during winter and autumn. In the FEEM investigation the fulvic and humic substances were found in most sites, and in sites regarding Gwangju city (GJS, GJC, GJ2) during winter and GJC in summer, protein-like substances were found. The trend of fluorescence intensities from the upper reaches to the lower reaches in most sites corresponded to that regarding the concentration of water characteristics (BOD, COD, TN, DOC). That is why the region of Gwangju city (GJS, GJC, GJ2) was relatively higher. This results were an equivalent trend to those of fluorescence index (FI) in most sites, and the higher FIs in the sites of Gwangju city indicate more microbial-derived substances due to enormous effluent organic matters (EfOM) from huge Gwangju sewage treatment plants.

• Korean Journal of Organic Agriculture
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• v.14 no.1
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• pp.69-83
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• 2006

This experiment was conducted to investigate effects of application of diluted and undiluted cattle slurry with water on seasonal and annual dry matter yields and feed values of tall fescue in the uncultivated rice paddy and it was compared with chemical fertilizer. Annual dry matter yields for diluted (average 6.43 ton DM/ha) and undiluted (average 6.56 ton DM/ha) cattle slurry were significantly higher (p<0.05) than those of no fertilizer (3.82 ton DM/ha). This trend was much more conspicuous in treatments applied in spring. In chemical fertilizer treatments, fertilizers with P and K (6.12 ton DM/ha), and P, K and N (10.13 ton DM/ha) had significantly (p<0.05) higher dry matter yields compared with no fertilizer. However, annual dry matter yields for treatments of P and K mixture tended to be lower than those of cattle slurry applications. The efficiency of DM production for inorganic nitrogen in chemical fertilizers annually averaged 26.7kg DM/kg N. In terms of cutting frequencies, it was highest in 2nd growth followed by 1st and 3rd growth. On the other hand, efficiencies of annual DM production of nitrogen for diluted and undiluted cattle slurry were 18.3 and 17.4 kg DM/kg N, respectively, especially, highest in 2nd growth. While, efficiencies of DM production for cattle slurry versus for inorganic nitrogen were 68.5 (undiluted) and 65.2% (diluted), respectively. For annual crude protein contents of tall fescue, no fertilization (11.5%) was significantly higher than chemical fertilizer, but that was lower than cattle slurry ($12.4{\sim}12.6%$) diluted with water. on the contrary, no fertilizers had significantly lower NDF (64.1%) and ADF (37.2%) contents than those of any other treatments, but their RFV (87.0) was significantly higher (p<0.05) than other treatments. The application of cattle slurry and their dilution significantly increased yields of crude protein and total digestible nutrients compared with no and/or P and K fertilizers (p<0.05). This trend was more conspicuous in cattle slurry applied in the early spring.

• Korean Journal of Ecology and Environment
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• v.33 no.1 s.89
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• pp.51-60
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• 2000

In order to understand the trend and assessment of water pollution, seasonal water quality was determined in the main river and the tributaries from midstream to downstream of the Kum River from March 1998 to June 1999. Among environmental factors, the variation of nitrogen, phosphorus and chlorophyll-a was distinctive on an aspect of increase and decrease relatively to others, and particularly the impact of inorganic N ${\cdot}$ P inflowing into the main river was observed to be more significant at the Kapchon, Mihochon and Soksongchon among the tributaries. Water quality was highly related to hydrologic factor, and it was more deteriorated when water discharge maintains for a long time below normal flow or relatively at low condition of minimum and drought flow. These phenomena were remarkablee from December to March of the next year. $NH_4$ and SRP were decreased dramatically flowing toward the lower part of the river and chl-a was increased exponentially. While, the variations of $NO_3$ and $BOD_5$ were regular from midstream to downstream and there was no significant difference between the stations. Limiting nutrient for Phytoplankton growth seemed to be P than N because the ratio of TN/TP or DIN/SRP was relatively high as 42 or 544 in the main river, respectively. The main river and tributaries were ranked to be third grade, based on the assessment of BOD as an indirect indicator of organics, but particularly Kapchon was ranked to be over fifth grade. In addition, the inflow of high N ${\cdot}$ P nutrients from tributaries including Kapchon and Mihochon seemed to be major factor of the development of water pollution of the Kum River. On the other hand, persistent bloom of phytoplankton in lower part of the river was observed. As a conclusion, management of water quality for main source of pollution is urgent.

• Journal of Food Hygiene and Safety
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• v.34 no.3
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• pp.251-262
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• 2019

In this study, we analyzed Korean dietary habits with food intake data from the Korea National Health and Nutrition Examination Survey (KNHANES) and the Korea Centers for Disease Control and Prevention and we proposed a set of management guidelines for future Korean dietary habits. A total of 839 food items (1,419 foods) were analyzed according to the food catagories in "Food Code", which is the representative food classification system in Korea. The average total daily food intake was 1,585.77 g/day, with raw and processed foods accounting for 858.96 g/day and 726.81 g/day, respectively. Cereal grains contributed to the highest proportion of the food intake. Over 90% of subjects consumed cereal grains (99.09%) and root and tuber vegetables (95.80%) among the top 15 consumed food groups. According to the analysis by item, rice, Korean cabbage kimchi, apple, radish, egg, chili pepper, onion, wheat, soybean curds, potato, cucumber and pork were major (at least 1% of the average daily intake, 158.6 g/day) and frequently (eaten by more than 25% of subjects, 5,168 persons) consumed food items, and Korean spices were at the top of this list. In the case of kimchi, the proportion of intake of Korean cabbage kimchi (64.89 g/day) was the highest. In the case of alcoholic beverages, intake was highest by order of beer (63.53 g/day), soju (39.11 g/day) and makgeolli (19.70 g/day), and intake frequency was high in order of soju (11.3%), beer (7.2%), and sake (6.6%). Analysis results by seasonal intake trends showed that cereal grains have steadily decreased and beverages have slightly risen. In the case of alcoholic beverage consumption frequency, some kinds of makgeolli, wine, sake, and black raspberry wine have decreased gradually year by year. The consumption trend for kimchi has been gradually decreasing as well.

• Korean Journal of Heritage: History & Science
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• v.57 no.3
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• pp.116-137
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• 2024

This study quantitatively explored the interrelationship between water features and surrounding waterscape elements through a literature review and observational study targeting nine waterscapes of Suzhou Classical Garden in Jiangsu Province, China, which is designated as a UNESCO World Heritage Site. The purpose was to understand the objective characteristics of classical Chinese gardens and seek a basis for their differences from Korean gardens. The average area of water space in Suzhou gardens was 1,680.7㎡, which accounted for 21.3% of the total garden area, showing large variation by garden. Most of the Suzhou Gardens use springs and wells as their water sources. The Surging Waves Pavillion uses surface water, and Retreat & Reflection Garden uses seasonal water as its water source. The water pipes in Suzhou Garden are divided into a water outlet and a water outlet(water holes). Of these, the water outlet is a water outlet that imitates the water outlet just to induce a visual effect, and focuses on the meaning of the water system. It is judged to have been combined with the trend of Suzhou gardens. In addition, it was confirmed that, semantically, the arrangement of the water polo in Suzhou Garden is based on the traditional 'Gamyeo(堪輿) theory'. Meanwhile, there are five types of methods for bringing water to Suzhou Garden: Jiginbeop(直引法), Myeonggeobeop(明渠法), Invasionbeop(滲透法), Gwandobeop(管道法), and Chakjeongbeop(鑿井法). Suzhou Classical Garden mainly applies the infiltration method and the irrigation method as a method of securing water in the garden, which can be classified and defined as the water catchment method(集水法) and the water pulling method(引水法) in the domestic classification method. Among the watering techniques in Korean traditional gardens, watering methods such as 'suspension waterfall(懸瀑)', 'flying waterfall(飛瀑)' and water eluted(湧出), have not been found, and it is believed that they mainly 'rely on hide with dignity(姿逸)' and 'submerged current(潛流)' techniques. As for the watering technique, no watering technique was found that uses a Muneomi, which is applied in traditional Korean gardens. As this was applied, the seal method, penetration method, and Gwandobeop were also used in water extraction techniques. And at the inlet and outlet of Suzhou Garden, the main static water bodies were lakes, swamps, and dams. While the eastern water bodies are classified into streams, waterfalls, and springs, the water spaces in the three gardens reflect the centrifugal distributed arrangement, and the water spaces in the six places reflect the water landscape effect due to the centripetal concentrated arrangement. And as a water space landscape design technique, the techniques of 'Gyeok(隔)' and 'Pa(破)' were mainly applied at the inlet, and the techniques of 'Eom(隔)' and 'Pa(破)' were mainly applied at the outlet. For example, most bridges were built around the inlet, and sa(榭), heon(軒), gak(閣), pavilion(亭), and corridor(廊) were built, and the outlet was concealed with a stone wall. Therefore, it is understood to have embodied Suzhou Garden's idea of water(理水), which says, "Although it was created by humans, it is as if the sky is mine(雖由人作，宛自天開)."A trend was detected. Lastly, as a result of analyzing the degree of concealment and exposure in the visual composition of the inlet and outlet, it was confirmed that the water outlet was exposed only at the Eobijeong and Mountain Villa with Embracing Beauty view points of The Surging Waves Pavillion and the water outlet was hidden at other view points. Looking at these results, the 'Hyang-Hyang-Ba-Mi-Bob(向向發微法)' from the perspective of left-orientation theory of Feng Shui, which is applied in Korean traditional gardens in classical Chinese garden water management, "makes water visible as it comes in, but invisible as it goes out." It is judged that the technique was barely matched.

• The Journal of Fisheries Business Administration
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• v.4 no.1_2
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• pp.19-57
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• 1973

Laver io one of the most necessary and seasonal items in Korean food from oldtimes. Laver is lagely eaten in dried form, and its supply depends entirely upon culture weeds. The history of laver culture in Korea about sixty or seventy years is older than in Japan. Significance of laver culture is divided into two aspects, one is food supply in the nation, and the other is export to other countries. Houses engaged in laver culture are about foully thousands, and laver production in 1972 is estimated as 1, 3 bitten sheets. (1 sheet is a dried laver of 20 cm sq, in the shape of paper) Especcially meaning of layer production is the concentration of labour input, and systematic management of labour. From around 1920, the method of laver culture was introduced by Japanese Imperialism for mono culture in shallow seas, and mass products of laver is provided to Japan market, DOMESTIC MARKET Fundamental consume function calculates at below, $D_{(68_71)}$=16354 $Y^{0.471}$ $P^{-1.0662}$ where D is total layer demand, Y income variable, P price variable. It means income elasticity is 476. in the whole country, and price elasticity is 1, 07. But generally income elasticity is higher in urban area than in rural area, as shown at 1, 3 in Seoul city. Expence of laver in house expenditure is mutually correlated with another expence, See Table 12 about the relative function. See Table 14 and 16 about the relation between the gathering and the changes of price in auction, wholesale and retail price support system is for two effects, one of which is constraint of the upper price, the other is rise of the lower price. Before the system control, the equation in three year average calculated as below, $Y_{b}$ ＝18, 907.7455＋15435.9364 t (r=0.89) where the origin t＝0 is the November and the units are month. Post the system control, $Y_{p}$ =30, 047.9636+1, 631.1721t (r＝0.97) therefore, this system has an effect only on the rise of lower price, Average annual margins of laver products at four market levels according to the consumer spent is below. EXPORTING MARKET Japanese demand function of laver products is, Log D=5, 289+1, 108 Log Y-1, 395 Log P (r=0.987) where D is Japanese laver demand, Y income variable, P price variable. according to which income elasticity is 1. 1 and price elasticity is 1.4. Laver production in 1970 tile highest record till then, is estimated as six billion sheets. But the recent improvement of laver culture techniques, the production of seeds and freezing storage of seeds has been stabilized. Futher new culture farms have been developed by means of break- water fences or by floating culture method. These improvements have been backed up with increased demand of laver products. Import quantity and price of Korean laver products are restrained by three organizations, that is producer, distributor and consumer. This relationship calculated by regression equation shows that import is influenced only producer organization, at the sacrifice of consumer profit. For increase to export of laver products, we urgently require to open foreign trade of laver products for Japanese consumer, .and Japan has political responsibility to solve Korean laver structure. But with long run timeseries, as regards Japanese production and import quantity, importing function shows increasing trend as below, 250 million sheets ＜3, 947.1674+0.005 $L_{g}$ ＞) 600 million sheets where $L_{q}$ is relative production quantity of laver in Japan. (unit; 100 thousand sheets) Our Export effort should be put on the highly processed products whithin the restraind quote.ote.

• Korean Journal of Agricultural and Forest Meteorology
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• v.16 no.4
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• pp.396-402
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• 2014

The spring season in Korea features a dynamic landscape with a variety of flowers such as magnolias, azaleas, forsythias, cherry blossoms and royal azaleas flowering sequentially one after another. However, the narrowing of south-north differences in flowering dates and those among the flower species was observed in 2014, taking a toll on economic and shared communal values of seasonal landscape. This study was carried out to determine whether the 2014 incidence is an outlier or a mega trend in spring phenology. Data on flowering dates of forsythias and cherry blossoms, two typical spring flower species, as observed for the recent 60 years in 6 weather stations of Korea Meteorological Administration (KMA) indicate that the difference spanning the flowering date of forsythias, the flower blooming earlier in spring, and that of cherry blossoms that flower later than forsythias was 30 days at the longest and 14 days on an average in the climatological normal year for the period 1951-1980, comparing with the period 1981-2010 when the difference narrowed to 21 days at the longest and 11 days on an average. The year 2014 in particular saw the gap further narrowing down to 7 days, making it possible to see forsythias and cherry blossoms blooming at the same time in the same location. 'Cherry blossom front' took 20 days in traveling from Busan, the earliest flowering station, to Incheon, the latest flowering station, in the case of the 1951-1980 normal year, while 16 days for the 1981-2010 and 6 days for 2014 were observed. The delay in flowering date of forsythias for each time period was 20, 17, and 12 days, respectively. It is presumed that the recent climate change pattern in the Korean Peninsula as indicated by rapid temperature hikes in late spring contrastive to slow temperature rise in early spring immediately after dormancy release brought forward the flowering date of cherry blossoms which comes later than forsythias which flowers early in spring. Thermal time based heating requirements for flowering of 2 species were estimated by analyzing the 60 year data at the 6 locations and used to predict flowering date in 2014. The root mean square error for the prediction was within 2 days from the observed flowering dates in both species at all 6 locations, showing a feasibility of thermal time as a prognostic tool.

• Korean Journal of Environment and Ecology
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• v.30 no.6
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• pp.1009-1021
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• 2016

The community structure and abundance of epilithic biofilm were bimonthly examined to know spatial and temporal patterns of biofilm biomass and taxonimical composition at the two study sites, Gosapo and Gyeokpo with different degrees of wave exposure levels from November 2010 to September 2011. Biomass was estimated by using chlorophyll a contents (Chl a), normalized difference vegetation index (NDVI), and vegetation index (VI). Cyanobacteria such as Aphanotece spp. predominated in the proportion of 57.53% at Gosapo and of 61.12% at Gyeokpo and they are abundant in mid shore and in summer at both study sites. The diatoms Navicula spp., Achnanthes spp. and Licmophora spp. were common species and they showed an increasing trend from high to low shore. NDVI, VI, and chl a contents were the greatest at mid shore for Gosapo (0.44, 3.05, $24.56{\mu}g/cm^2$) and at low shore for Gyeokpo (0.41, 2.73, $17.98{\mu}g/cm^2$). NDVI, VI, and chl a content were all maximal in January and minimal in March at the both sites. Average NDVI, VI, and chlorophyll a contents of biofilms were greater at Gosapo (0.43, 2.89, $22.84{\mu}g/cm^2$) than Gyeokpo (0.38, 2.48, $15.48{\mu}g/cm^2$).Of three shore levels(high, mid, and low) Chl a contents were positively correlated with NDVI and VI at the two study sites indicating that non-destructive NDVI and VI values can be used in stead of destructive Chl a extraction method. In conclusion, epilithic biofilm was more abundant seasonally in winter, vertically in mid and low intertidal zone, and horizontally at wave exposed shore than in summer, at high and sheltered shore in Korea.

• Korean Journal of Agricultural and Forest Meteorology
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• v.18 no.3
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• pp.143-150
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• 2016

In this study, we analyzed the relationship between rice yield and abnormal meteorological features for El $Ni{\tilde{n}}o$ years (with more than 1.0 Oceanic $Ni{\tilde{n}}o$ Index) since 1980 in South Korea. The national averaged rice yield of El $Ni{\tilde{n}}o$ years (n=14) was $4,663kg\;ha^{-1}$, which was less than that of non El $Ni{\tilde{n}}o$ years (n=16) by $102kg\;ha^{-1}$, but the difference was not significant statistically (t=1.215, p=0.234). The averaged rice yield of El $Ni{\tilde{n}}o$ end years ($4,558kg\;ha^{-1}$) was analyzed to be less than those of El $Ni{\tilde{n}}o$ start years and non El $Ni{\tilde{n}}o$ years by 209 and $206kg\;ha^{-1}$, respectively. But, the trend was not significant statistically (df=2, f=2.355, p=0.114). When meteorological anomalies were analyzed based on seasonal meteorological values, 18 meteorological events in total were observed for the past 30 years (1981-2010). In detail, abnormally much precipitation occurred 6 times, most often, followed by 5 times of abnormally low temperature during the past 30 years. Occurrence of meteorological anormalies of El $Ni{\tilde{n}}o$ end years was 0.71 events per year on average, which was higher than those of El $Ni{\tilde{n}}o$ start years ($0.43yr^{-1}$) and non El $Ni{\tilde{n}}o$ years ($0.63yr^{-1}$), even if the differences were not significant statistically (df=2, f=0.321, p=0.727).