• Proceedings of the KSRS Conference
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• 1999.11a
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• pp.485-490
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• 1999

Wind vector information over the ocean is currently obtained using multiple beam scatterometer data. The scatterometers on ERS-1/2 generate wind vector information with a spatial resolution of 50km and accuracies of $\pm$2m/s in wind speed and $\pm$20$^{\circ}$ in wind direction. Synthetic aperture radar (SAR) data over the ocean have the potential of providing wind vector information independent of weather conditions with finer resolution. Finer resolution wind vector information can often be useful particularly in coastal regions where the scatterometer wind information is often corrupted because of the lower resolution system characteristics which is often contaminated by the signal returns from the coastal areas or ice in the case of arctic environments. In this paper we tested CMOD_4 and CMOD_IFR2 algorithms for extracting the wind vector from SAR data. These algorithms require precise estimation of normalized radar cross-section and wind direction from the SAR data and the local incidence angle. The CMOD series algorithms were developed for the C-band, VV-Polarized SAR data, typically for the ERS SAR data. Since RADARSAT operates at the same C-band but with HH-Polarization, the CMOD series algorithms should not be used directly. As a preliminary approach of resolving with this problem, we applied the polarization ratio between the HH and VV polarizations in the wind vectors estimation. Two test areas, one in front of Inchon and several sites around Jeju island were selected and investigated for wind vector estimation. The new results were compared with the wind vectors obtained from CMOD algorithms. The wind vector results agree well with the observed wind speed data. However the estimation of wind direction agree with the observed wind direction only when the wind speed is greater than approximately 3.0m/s.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.13 no.6
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• pp.590-596
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• 2020

In the island areas where system connection with the commercial power grid is difficult, it is quite important to find a method to efficiently manage energy produced with independent microgrids. In this paper, a prosumer management system for P2P power transaction was realized through the testing the power meter and the response rate of the collected data for the power produced in the small-scale microgrids in which hybrid models of solar power and wind power were implemented. The power network of the microgrid prosumer was composed of mesh structure and the P2P power transaction was tested through the power meter and DC power transmitter in the off-grid sites which were independently constructed in three places. The measurement values of the power meter showed significant results of voltage (average): 380V + 0.9V, current (average): + 0.01A, power: 1000W (-1W) with an error range within ±1%. Stabilization of the server was also confirmed with the response rate of 0.32 sec. for the main screen, 2.61 sec. for the cumulative power generation, and 0.11 sec for the power transaction through the transmission of 50 data in real time. Therefore, the proposed system was validated as a P2P power transaction system that can be used as an independent network without transmitted by Korea Electric Power Corporation (KEPCO).

• Journal of the Korean Institute of Landscape Architecture
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• v.35 no.1 s.120
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• pp.48-58
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• 2007

The purpose of this study was not only to clearly examine the features of the scenery and visual elements of Oreum (parasitic cones) but also to investigate primary factors in landscape preferences for these cones. This study further attempted to gain basic information for examining the preservation of Oreum in regards to the influence of scenery on the general public. A Multiple Regression Analysis was used for this study for which the independent variable was the area ratio of the fore-, mid-, and background of the view under the feature element and the structure of the scenery at the Oreum. The dependent variables were the preference value, the number of summits, and the highest altitude of the Oreum. All but the highest inclination were positive variables. The area ratio of the Oreum was found to be the most important variable. The area of sky and the area of the distant scenery were shown to be positive explanation variables, while the area to the fore of the view and the area to the middle of the view were shown as negative explanation variable. In the preference for Oreum scenery, which has a high visibility and is clearly outlined against the skyline, it was found that as the hindrance element of visibility near to a visual point or the area ratio increased, the preference for the Oreum scenery decreased.

• Atmosphere
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• v.24 no.1
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• pp.101-110
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• 2014

This study estimates and evaluates the daily January temperature from 2003 to 2012 with 30 m-resolution over South Korea, using a modified Parameter-elevation Regression on Independent Slopes Model (K-PRISM). Several factors in K-PRISM are also adjusted to 30 m grid spacing and daily time scales. The performance of K-PRISM is validated in terms of bias, root mean square error (RMSE), and correlation coefficient (Corr), and is then compared with that of inverse distance weighting (IDW) and hypsometric methods (HYPS). In estimating the temperature over Jeju island, K-PRISM has the lowest bias (-0.85) and RMSE (1.22), and the highest Corr (0.79) among the three methods. It captures the daily variation of observation, but tends to underestimate due to a high-discrepancy in mean altitudes between the observation stations and grid points of the 30 m topography. The temperature over South Korea derived from K-PRISM represents a detailed spatial pattern of the observed temperature, but generally tends to underestimate with a mean bias of -0.45. In bias terms, the estimation ability of K-PRISM differs between grid points, implying that care should be taken when dealing with poor skill area. The study results demonstrate that K-PRISM can reasonably estimate 30 m-resolution temperature over South Korea, and reflect topographically diverse signals with detailed structure features.

• Journal of Preventive Medicine and Public Health
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• v.9 no.1
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• pp.31-37
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• 1976

This study was conducted for the purpose of obtaining basic information on the patterns of medical care expenditures, and identifying some determinants of medical care expenditures in the rural Korea. Nine guns were chosen from the eight provinces, excluding Cheju island. One gun in each province and two villages were selected from the each myon or ub within the selected guns. The total number of households was 1,789 and the sample size was 9,826 non-institutionalized people. Followings are the major findings of the study : 1) Medical care expenditures increase proportionally with age in terms of cost per patient, per episode of illness, per treated case, and per person. Averagely, it cost 2,756 won per patient, 2,614 won per spell of illness, 4,361 won per treated case, and 413 won per person. 2) Medical care expenditures increase proportionally with educational level of patients. College graduates spent the most, 4,726 won per patient, 5,987 won per treated case, and 670 won per person. 3) The male spent a little more than the female in terms of per patient, per episode, and per person. For example, a male spent 23 won more than a female. 4) Those who were suffering from illnesses longer than 1 year spent three times more than that had illnesses of less than 1 year duration. 5) The simple correlation coefficient between activity restriction and medical care expenditures was the highest among others, 0.491. The next was 0.294 between duration of illness and medical care expenditures. 6) Attempts are made to identify the explanatory variables in medical care expenditures. Thirty one per cent of the variances in tile expenditures can be accounted for by the selected 15 predictors. Those predictors belonged to clinical renditions, such as activity restriction, duration of illness, and nature of conditions, are proved to be the most potent independent variabes. Level of education and monthly family income are also significant in terms of beta coefficient. Further studies are called for to unreveal the determinants of medical expenditures.

• 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 $-0.94Wm^{-2}$.

• 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.

• 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.

• 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%.

• 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.