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Wind Field Estimation Using ERS-1 SAR Data: The Initial Report

  • Won, Joong-Sun;Jeong, Hyung-Sup;Kim, Tae-Rim
    • Proceedings of the KSRS Conference
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    • 1998.09a
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    • pp.286-291
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    • 1998
  • SAR has provided weather independent images on land and sea surface, which can be used for extracting various useful informations. Recently attempts to estimate wind field parameters from SAR images over the oceans have been made by various groups over the world. Although scatterometer loaded in ERS-1 and ERS-2 observes the global wind vector field at spatial resolution of 50 Km with accuracies of $\pm$2m/s in speed, the spatial resolution may not be good enough for applications in coastal regions. It is weil known the sea surface roughness is closely correlated to the wind field, but the wind retrieval algorithms from SAR images are yet in developing stage. Since the radar backscattering properties of the SAR images are principally the same as that of scatterometer, some previous studies conducted by other groups report the success in mesoscale coastal wind field retrievals using ERS SAR images. We have tested SWA (SAR Wind Algorithm) and CMOD4 model for estimation of wind speed using an ERS-1 SAR image acquired near Cheju Island, Korea, in October 11, 1994. The precise estimation of sigma nought and the direction of wind are required for applying the CMOD4 model to estimate wind speed. The wind speed in the test sub-image is estimated to be about 10.5m/s, which relatively well agrees to the observed wind speed about 9.0m/s at Seoguipo station. The wind speed estimation through the SWA is slightly higher than that of CMOD4 model. The sea surface condition may be favorable to SWA on the specific date. Since the CMOD4 model requires either wind direction or wind speed to retrieve the wind field, we should estimate the wind speed first using other algorithm including SWA. So far, it is not conclusive if the SWA can be used to provide input wind speed data for CMOD4 model or not. Since it is only initial stage of implementing the wind field retrieval algorithms and no in-situ observed data is currently avaliable, we are not able to evaluate the accuracy of the results at the moment. Therefore verification studies should be followed in the future to extract reliable wind field information in the coastal region using ERS SAR images.

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A Study on Optimal Design of Hybrid System of New and Renewable Energy-Linked Microgrid (신재생에너지 연계형 마이크로그리드의 하이브리드시스템 최적 설계 연구)

  • Lee, Jae-Kyung;Han, Yong-Chan;Kwon, Sung-Gi;Park, Gye-Choon
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.35 no.6
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    • pp.631-638
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    • 2022
  • Microgrid, which enables the production and consumption of electricity to be done independently on a small scale, has been studied on one of the solutions of reinforcement for flexibility of electronic system. This study examined the application effect of new microgrid by applying hybrid battery in electric power storage device. We designed the system to highlight the advantage of each battery and complement the disadvantage by using hybrid system with Lithium-ion battery and interval Redox flow battery. It runs with lithium-ion battery during the initial startup while the Redox flow battery operates for a long time at the end of excessive period, and it enables a discharge of Lithium-ion and Redox flow battery at the same time when the load has a large output. We chose Maldives as a subject of this study for organizing and optimizing independent microgrid. Maldives is the country to accomplish 100% domestic electricity in South Asia, but the whole electric power is supplied through diesel generation imported fossil fuel. We organized and optimized microgrid for energy independence on Malahini island to solve Maldives energy cost problem and global energy environment matters. We analyzed the daily power supply and accumulated the power supply from September 18, 2018~February 11, 2019. The accumulated power supply was about 120.4 MWh and the daily power supply was about 800~1000 kWh. Based on the collected information, we divided the cases into three models which are only diesel generator, solar generator as well as diesel generator, and solar+ESS+diesel generator. We analyzed the amount of oil consumption compared to the cost of construction and power output. The result showed that solar+ESS+diesel generator was most economically feasible. As well, we obtained that our considering hybrid battery system reduced the fuel consumption for diesel power generation about 10~15%.

Analysis of the Landscape Conservation Direct Payment System Based on Spatial Information Data and Utilization of Rural Area Regeneration (공간정보데이터 기반의 경관보전직불제도 실태분석과 농촌공간 재생의 활용방안)

  • Kim, Young-Jin;Kang, Dong-Jin;Choi, Jin-ah;Son, Yong-hoon
    • Journal of Korean Society of Rural Planning
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    • v.29 no.3
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    • pp.39-52
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    • 2023
  • There is a clear need to enhance the attractiveness of rural areas by leveraging their core assets to respond to emerging mega-trends. This paper analyzes the progress of the direct payment program that has been implemented to preserve agricultural landscapes in rural areas, using spatial information data. The study identified the planting characteristics of landscape crops, spatial utilization characteristics of the system, and utilization characteristics of the system by the beneficiaries. According to the analysis, the spatial utilization characteristics of the system could be classified into eight types: tourism resources and nearby agricultural areas, designation across the entire rural area, agricultural areas around villages, large-scale agricultural areas, small-scale agricultural areas, scattered and dispersed areas, independent parcels of land, and ranches. Based on the characteristics and limitations of the landscape preservation direct payment system, this study provides directions for future rural specialized zones. The landscape preservation direct payment system focuses on income support for farmers and providing agricultural benefits in terms of public interest. Meanwhile, the landscape agricultural zone serves as a rural specialized zone, highlighting the need to explore the direction of integrated rural landscape management. It is important for farmers, as the key stakeholders, to preserve the agricultural landscape in rural areas. Forming community-level cooperatives and engaging in relevant activities are crucial for achieving this goal. In order to actively preserve the agricultural landscape, it is necessary to consider the resumption of financial support for village landscape preservation activities, along with the designation of landscape agricultural zones. There is a need to conduct a specific review and explore measures to accommodate the designated landscape complexes at the local government level. The higher the ratio of designated landscape complexes, the more agricultural landscape management based on public value has been carried out. The designation of such landscape complexes can be seen as a demand for voluntary utilization of agricultural landscapes in the region. Moreover, as the ratio of designated landscape complexes increases, it becomes evident that farmers at the village level actively participate in agricultural landscape preservation and contribute to providing public value or utilize it as a tourism resource. This highlights the need for managing agricultural landscapes at the village level within the appropriate context.

Characterization of clutch traits and egg production in six chicken breeds

  • Lei Shi;Yunlei Li;Adam Mani Isa;Hui Ma;Jingwei Yuan;Panlin Wang;Pingzhuang Ge;Yanzhang Gong;Jilan Chen;Yanyan Sun
    • Animal Bioscience
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    • v.36 no.6
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    • pp.899-907
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    • 2023
  • Objective: The better understanding of laying pattern of birds is crucial for developing breed-specific proper breeding scheme and management. Methods: Daily egg production until 50 wk of age of six chicken breeds including one layer (White Leghorn, WL), three dual-purpose (Rhode Island Red, RIR; Columbian Plymouth Rock, CR; and Barred Plymouth Rock, BR), one synthetic dwarf (DY), and one indigenous (Beijing-You Chicken, BYC) were used to characterize their clutch traits and egg production. The age at first egg, egg number, average and maximum clutch length, pause length, and number of clutches and pauses were calculated accordingly. Results: The egg number and average clutch length in WL, RIR, CR, and BR were higher than those in DY and BYC (p<0.01). The numbers of clutches and pauses, and pause length in WL, RIR, CR, and BR were lower than those in DY and BYC (p<0.01). The coefficient variations of clutch length in WL, RIR, CR, and BR (57.66%, 66.49%, 64.22%, and 55.35%, respectively) were higher than DY (41.84%) and BYC (36.29%), while the coefficient variations of egg number in WL, RIR, CR, and BR (9.10%, 9.97%, 10.82%, and 9.92%) were lower than DY (15.84%) and BYC (16.85%). The clutch length was positively correlated with egg number (r = 0.51 to 0.66; p<0.01), but not correlated with age at first egg in all breeds. Conclusion: The six breeds showed significant different clutch and egg production traits. Due to the selection history, the high and median productive layer breeds had higher clutch length than those of the less productive indigenous BYC. The clutch length is a proper selection criterion for further progress in egg production. The age at first egg, which is independent of clutch traits, is especially encouraged to be improved by selection in the BYC breed.

Spatio-Temporal Characteristics of Droughts in Korea: Construction of Drought Severity-Area-Duration Curves (가뭄의 시공간적 분포 특성 연구: 가뭄심도-가뭄면적-가뭄지속기간 곡선의 작성)

  • Kim, Bo Kyung;Kim, Sang Dan;Lee, Jae Soo;Kim, Hung Soo
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.26 no.1B
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    • pp.69-78
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    • 2006
  • The rainfall depth-area-duration analysis which is used to characterize precipitation extremes for specification of so-called design storms, provides a basis for evaluation of drought severity when storm depth is replaced by an appropriate measure of drought severity. So we propose a method for constructing drought severity-area-duration curves in this study. Monthly precipitation data over the whole Korea are used to compute SPI. Such SPIs are abstracted to several independent spatial components from EOF analysis. Using Kriging method, these spatial components are used to constitute grid-based SPI data set over the whole Korea including Jeju island with $6km{\times}6km$ resolution. After identifying main drought events, the drought severity-area-duration curves for these events over 32-year period of record are finally constructed. As a result, such curves show the similar shape with storm-based curves in the sense that the drought severity (or rainfall depth) is inversely proportional to drought area from the curves, but drought-based curves are different from storm-based curves in the sense that the drought severity decreasing rate with respect to drought area is much less than depth decreasing rate.

On the Microdistribution of Fresh-Water Fish, Coreoleuciscus splendidus(Gobioninate) from Korea (한국산(韓國産) 담수어(淡水魚), 쉬리 Coreoleuciscus splendidus의 미세분포(微細分布)에 관(關)하여)

  • Choi, Ki-Chul;Choi, Shin-Sok;Hong, Young-Pyo
    • Korean Journal of Ichthyology
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    • v.2 no.1
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    • pp.63-76
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    • 1990
  • Studies on the microdistribution, distributional aspect and affinity of Korean endemic species, SHIRl, Coreoleueiseus splendidus in th southern half of the Korean peninsula were carried out from May, 1966 to November, 1989. This species was found in 14 independent rivers and streamlets of the south Korea ; Yimjin R., Han R., Kum R., Ungchun S., Mangyung S., Dongjin R., Somjin R., Kwangyang East S., Sachun S., Gonyang S., Nakdong R., Samchukosip S., Samhwa S. of Namhae Island and Guchun S. of Geojae Islands, and were not found from Youngsan R., Ansung S. and Sabgyo S. This species was not common and independent comprising less than 25% of the total fish population in all habiting sites. Distributional zone was in the middle or upper streaches of main streams and tributaries. The average slope of distributional zone was 2.6, minimum slope was 0.29 and maximum slope was 5.56. Thirty-three species were found to occur along with this fish and 10 species of them occurred with more than 50% frequency. They were; 20 sp. of Cyprinidae, 5 sp. of Cobitidae, 1 sp. of Salmonidae, 1 sp. of Bagfridae, 1 sp. of Siluridae, 2 sp. of Amblycipitidae, of Serranidae, and 1 sp. of Eleotridae. Some species of fish appeared to have the same ecological position even though they have different distributional zones. These species were as follows; Acheilognathus signifer and A. limbata, Micriophsogobio koreensis and M. yaluensis in Cyprinidae, Cobitis koreensis, C. longicorpus, C. rotundicaudata in Cobitidae, Liobagrus andersoni and L. mediadiposalis in Amblycipitidae.

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A Study on Retrieval of Storage Heat Flux in Urban Area (우리나라 도심지에서의 저장열 산출에 관한 연구)

  • Lee, Darae;Kim, Honghee;Lee, Sang-Hyun;Lee, Doo-Il;Hong, Jinkyu;Hong, Je-Woo;Lee, Keunmin;Lee, Kyeong-sang;Seo, Minji;Han, Kyung-Soo
    • Korean Journal of Remote Sensing
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    • v.34 no.2_1
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    • pp.301-306
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    • 2018
  • Urbanization causes urban floods and urban heat island in the summer, so it is necessary to understanding the changes of the thermal environment through urban climate and energy balance. This can be explained by the energy balance, but in urban areas, unlike the typical energy balance, the storage heat flux saved in the building or artificial land cover should be considered. Since the environment of each city is different, there is a difficulty in applying the method of retrieving the storage heat flux of the previous research. Especially, most of the previous studies are focused on the overseas cities, so it is necessary to study the storage heat retrieval suitable for various land cover and building characteristics of the urban areas in Korea. Therefore, the object of this study, it is to derive the regression formula which can quantitatively retrieve the storage heat using the data of the area where various surface types exist. To this end, nonlinear regression analysis was performed using net radiation and surface temperature data as independent variables and flux tower based storage heat estimates as dependent variables. The retrieved regression coefficients were applied to each independent variable to derive the storage heat retrieval regression formula. As a result of time series analysis with flux tower based storage heat estimates, it was well simulated high peak at day time and the value at night. Moreover storage heat retrieved in this study was possible continuous retrieval than flux tower based storage heat estimates. As a result of scatter plot analysis, accuracy of retrieved storage heat was found to be significant at $50.14Wm^{-2}$ and bias $-0.94Wm^{-2}$.

Foreign Entry Strategies for Korean Fishery Firms (한국수산업의 해외진출전략에 관한 연구)

  • 김회천
    • The Journal of Fisheries Business Administration
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    • v.15 no.1
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    • pp.131-153
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    • 1984
  • Fishery resources are still abundant compared with other resources and the possibility of exploitation is probably great. The Korean fishery industry has grown remarkably since 1957, and Korea is ranked as one of the major fishery countries. Its of fishery products reached the 9th in the world and the value of exports was 5th in 1982. But recently a growth rate has slowed down, due to the enlargement of territorial seas by the declaration of the 200 mile, Exclusive Economic Zone, the tendency to develop fishery resources strate-gically in international bargaining, the change in function of the international organizations, the expansion of regulated waters, the illegal arrest of our fishing boats, the rapid rise in oil prices, and the fall in fish prices, the development of fishery resources as a symbol of nationalism, the fishing boats decreptitude, the rise of crew wages, regulations on fishing methods, fish species, fishing season, size of fish, and mesh size, fishing quotas and the demand of excessive fishing royalties. Besides the the obligation of coastal countries, employing crews of their host countries is also an example of the change in the international environment which causes the aggravation of foreign profit of fishing firms. To ameliorate the situation, our Korean fishery firms must prepare efficient plans and study systematically to internationalize themselves because such existing methods as conventional fishing entry and licence fishing entry are likely to be unable to cope with international environmental change. Thus, after the systematic analysis of the problem, some new combined alternatives might be proposed. These are some of the new schemes to support this plan showing the orientation of our national policy: 1. Most of the coastal states, to cope with rapid international environmental change and to survive in the new era of ocean order, have rationalized their higher governmental structure concerning the fishery industries. And the coastal countries which are the objectives of our expecting entry, demand excessive economic and technical aid, limit the number of fishing boats’entry and the use of our foreign fishing bases, and regulate the membership of the international fishery commissions. Especially, most of the coastal or island countries are recently independent states, which are poorer in national budget, depend largely on fishing royalties and licence entry fees as their main resources of national finance. 2. Alternatives to our entry to deep sea fishing, as internationalization strategies, are by direct foreign investment method. About 30 firms have already invested approximately US $ 8 million in 9 coastal countries. Areas of investment comprise the southern part of the Atlantic Ocean, the Moroccan sea and five other sea areas. Trawling, tuna purse seining and five other fields are covered by the investment. Joint-venture is the most prominent method of this direct investment. If we consider the number of entry firms, the host countries, the number of seas available and the size of investment, this method of cooperation is perhaps insufficient so far. Our fishery firms suffer from a weakness in international competitive ability, an insufficiency of information, of short funds, incompetency in the market, the unfriendliness of host coastal countries, the incapability of partners in joint-ventures and the political instability of the host countries. To enlarge our foreign fishing grounds, we are to actively adopt the direct investment entry method and to diversity our collaboraboration with partner countries. Consequently, besides proper fishing, we might utilize forward integration strategies, including the processing fied. a. The enterprise emigration method is likely to be successful in Argentina. It includes the development of Argentinian fishing grounds which are still not exploited in spite of abundant resources. Besides, Arentina could also be developed as a base for the exploitation of the krill resources and for further entries into collaboration with other Latin American countries. b. The co-business contract fishing method works in American territorial seas where American fishermen sell their fishery products to our factory ships at sea. This method contributes greatly to obtaining more fishing quotas and in innovation bottom fishing operation. Therefore we may apply this method to other countres to diffuse our foreign fishing entry. c. The new fishing ground development method was begun in 1957 by tuna long-line experimental fishing in the Indian Ocean. It has five fields, trawling, skipjack pole fishing and shrimp trawling, and so on. Recently, Korean fisheries were successful in the development of the Antarctic Ocean krill and tuna purse seining. 3. The acceleration of the internationalization of deep sea fishing; a. Intense information exchange activities and commission participation are likely to be continues as our contributions to the international fishery organizations. We should try to enter international fishery commissions in which we are not so far participating. And we have to reform adequately to meet the changes of the function of the international commissions. With our partner countries, we ought to conclude bilateral fishery agreements, thus enlarging our collaboration. b. Our government should offer economic and technical aids to host countries to facilitate our firms’fishery entry and activities. c. To accelerate technical innovation, our fishery firms must invest greater amount in technical innovation, at the same time be more discriminatory in importing exogeneous fishery technologies. As for fishing methods; expanded use of multi-purpose fishing boats and introduction of automation should be encuraged to prevent seasonal fluctuations in fishery outputs. d. The government should increases financial and tax aid to Korean firms in order to elevate already weak financial structure of Korean fishery firms. e. Finally, the government ought to revise foreign exchange regulations being applied to deep sea fishery firms. Furthermore, dutes levied on foreign purchaed equipments and supplies used by our deep sea fishing boats thould be reduced or exempted. when the fish caught by Korean partner of joint-venture firms is sold at the home port, pusan, import duty should be exempted.

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Developing Korean Forest Fire Occurrence Probability Model Reflecting Climate Change in the Spring of 2000s (2000년대 기후변화를 반영한 봄철 산불발생확률모형 개발)

  • Won, Myoungsoo;Yoon, Sukhee;Jang, Keunchang
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.18 no.4
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    • pp.199-207
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    • 2016
  • This study was conducted to develop a forest fire occurrence model using meteorological characteristics for practical forecasting of forest fire danger rate by reflecting the climate change for the time period of 2000yrs. Forest fire in South Korea is highly influenced by humidity, wind speed, temperature, and precipitation. To effectively forecast forest fire occurrence, we developed a forest fire danger rating model using weather factors associated with forest fire in 2000yrs. Forest fire occurrence patterns were investigated statistically to develop a forest fire danger rating index using times series weather data sets collected from 76 meteorological observation centers. The data sets were used for 11 years from 2000 to 2010. Development of the national forest fire occurrence probability model used a logistic regression analysis with forest fire occurrence data and meteorological variables. Nine probability models for individual nine provinces including Jeju Island have been developed. The results of the statistical analysis show that the logistic models (p<0.05) strongly depends on the effective and relative humidity, temperature, wind speed, and rainfall. The results of verification showed that the probability of randomly selected fires ranges from 0.687 to 0.981, which represent a relatively high accuracy of the developed model. These findings may be beneficial to the policy makers in South Korea for the prevention of forest fires.

The Prognostic Factors Affecting the Occurrence of Subsequent Unprovoked Seizure in Patients Who Present with Febrile Seizure after 6 Years of Age (6세 이후 열경련 환자의 비열성발작으로 진행되는 위험 인자)

  • Lee, Hyeon Ju;Kim, Seung Hyo
    • Journal of the Korean Child Neurology Society
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    • v.26 no.4
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    • pp.215-220
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    • 2018
  • Purpose: Few reports have described the prognostic factors affecting the occurrence of subsequent unprovoked seizure in patients who present with febrile seizure (FS) after 6 years of age. We investigated the prognostic factors affecting the development of unprovoked seizures after FS among patients from Jeju Island. Methods: We included patients who developed FS after 6 years of age, who presented to our outpatient clinic between January, 2011 and June, 2017. Clinical data were obtained through chart reviews and phone call interviews. We used logistic regression analysis to analyze the risk factors associated with the occurrence of subsequent unprovoked seizure. Results: Of the 895 patients who presented to our hospital due to their febrile seizure, 83 developed FS after 6 years of age. Among them, 3 patients were prescribed antiepileptic drugs before the onset of the unprovoked seizure, and 4 patients developed an unprovoked seizure before 6 years of age. Thus, overall, 76 patients were included in the study. 51 patients developed first FS before 6 years of age. In the remaining patients, the first FS developed after 6 years of age. The mean observational period since the last outpatient follow-up visit was 3.2 years (median 3.04 years, range: 1.42-4.71 years). Among them, 21% developed an unprovoked seizure. Logistic regression analysis showed that electroencephalographic (EEG) abnormalities served as an independent risk factor for a subsequent unprovoked seizure. Conclusion: EEG is the proper diagnostic tool to predict the risk of a subsequent unprovoked seizure in patients with FS after 6 years of age.