• Spatial Information Research
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• v.21 no.1
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• pp.63-73
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• 2013

Geographic features are reflected in satellite images, which contain characteristic elements. Information on changes can be obtained through a comparison of images taken at different times. If multi-temporal images can be classified through the use of an unsupervised method, this is likely to improve the accuracy of image classification and contribute to various applications. A rule-based image classification algorithm for automatic processing without human involvement has been developed, but it must be verified that its results are not affected by imperfect elements. In this study, Landsat images of Jeju Island were used to carry out a rule-based image classification. The application results were examined for complex cases, including the presence of clouds in the images, different photographed times, and the type of target area, such as city, mountain, or field. The presence of clouds did not affect calculations, and appropriate classification rules were applied, depending on the different photographed times. The expansion of the urban areas of Jeju and the increase of facilities such as vinyl greenhouses in Seoguipo were identified. Furthermore, space information changes and accurate classifications for Jeju Island were obtained. With the goal of performing high-quality unsupervised classifications, measures to generalize and improve the methods employed were searched for. The findings of this study could be used in time-series analyses of images for various applications, including urban development and environmental change monitoring.

• Journal of the Korean Association of Geographic Information Studies
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• v.6 no.1
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• pp.119-131
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• 2003

Rainfall-runoff process is under the control of hydrologic parameters having temporal and spatial variety. Accordingly, it is difficult to efficiently deal them since many parameters and various information are required to perform hydrologic simulation. So the purposes of this study is to estimate the runoff volume by frequency using GIS techniques and NRCS method. The analysis of frequency rainfall is analyzed using FARD 2002 program and the result of goodness of fit test show that Log-pearson type III is suitable distribute type for the applied area. TOPAZ program used for the analysis of DEM data examining into geological characteristic. NRCS curve numbers estimated using landuse map and soil map for the estimation of effective rain fall in the basin. The storm Type II and Type III were used as the type for the application of NRCS. The result of application show that the runoff volumes above 80 years frequency in return period have similar patterns regardless of Type II and Type III. In addition, the results of comparison with runoff volumes by frequency in the report of river improvement master plan show that it have similar volumes as the relative errors for them of 80, 100 years frequency are each 7.65%, 5.33%.

• Sleep Medicine and Psychophysiology
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• v.1 no.1
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• pp.47-59
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• 1994

Objectives: The main purpose of this study was to investigate the possible differences in sleepiness, performance, and body temperature during the night between morning(M) and evening(E) type subjects. Methods: After a survey study, to verify the validity and reliability of the Korean translation of the Home' and $\ddot{O}stberg's$ Morningness-Eveningness Questionnaire(1976), 8 extreme M-type subjects(3males, 5 females) and 8 extreme E-type subjects(3 males, 5 females) were selected from the university student population who had participated in the survey study. All subjects underwent sleep latency test and a battery of performance tests at intervals of 2 hours through the night, from 23:00 to 07:00. Oral temperature of each subject was taken every hour from 21 : 00 to 8 : 00. Between the testing times, the experimenters ensured that subjects remained awake. Results: More profound sleepiness was found in the M-type compared to the E-type throughout the night, with significant differences in sleepiness occuring at 23:00 and 01:00 hours. Overall performance efficiency tended to be lower through, the night in the M-type than in the E-type on all tests. A difference in time of temperature minimum between the two types was not noteworthy. Rather, there appeared to be a substantial difference in temperature level during the declining phase, with the temperature of the M-type being lower than that of the E-type. Conclusions: These results indicate the existance of a temporal relationship between sleepiness, perfonnance and body temperature during night work. Since the M-type exhibited greater sleepiness and lower performance efficiency overnight than the E-type, it may be assumed that the E-type is more suitable for and tolerable to night work. There was some discussion of the limitations in generalizing these results together with some suggestions for future studies.

• Journal of the Korean Association of Geographic Information Studies
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• v.20 no.1
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• pp.1-14
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• 2017

A land cover map provides basic information to help understand the current state of a region, but its utilization in the ecological research field has deteriorated due to limited temporal and spatial resolutions. The purpose of this study was to investigate the possibility of using a land cover map with data based on high resolution images acquired by UAV. Using the UAV, 10.5 cm orthoimages were obtained from the $2.5km^2$ study area, and land cover maps were obtained from object-based and pixel-based classification for comparison and analysis. From accuracy verification, classification accuracy was shown to be high, with a Kappa of 0.77 for the pixel-based classification and a Kappa of 0.82 for the object-based classification. The overall area ratios were similar, and good classification results were found in grasslands and wetlands. The optimal image segmentation weights for object-based classification were Scale=150, Shape=0.5, Compactness=0.5, and Color=1. Scale was the most influential factor in the weight selection process. Compared with the pixel-based classification, the object-based classification provides results that are easy to read because there is a clear boundary between objects. Compared with the land cover map from the Ministry of Environment (subdivision), it was effective for natural areas (forests, grasslands, wetlands, etc.) but not developed areas (roads, buildings, etc.). The application of an object-based classification method for land cover using UAV images can contribute to the field of ecological research with its advantages of rapidly updated data, good accuracy, and economical efficiency.

• Journal of Aquaculture
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• v.20 no.2
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• pp.121-126
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• 2007

Comparison of fish number on routine oxygen consumption (OC) of black porgy (Acanthopagrus schlegeli) reared in seawater (SW) versus freshwater (FW) was performed in closed water-recirculating system containing respiratory chamber. Fish acclimated in separate indoor tanks with SW or FW were sampled as two groups (one or three of fish used, $mean\;{\pm}\;S.D.=36.4{\pm}9.8$). OC of fish reared in both SW and FW showed clear temporal rhythms, with higher values in the daytime and lower values at night, in accordance with light (09:00-21:00 h) and dark (21:00-09:00 h) phases of the diel cycle (12L:12D). The OC of the fish increased linearly with the water temperature. The OCs of black porgy reared in SW and FW at 15, 20, $25^{\circ}C$ were 140.0, 174.8, 282.3 mg $O^2{\cdot}kg^{-1}{\cdot}h^{-1}$ and 177.5, 307.8, 413.1 mg $O^2{\cdot}kg^{-1}{\cdot}h^{-1}$ for the one of fish used, and 200.5, 274.7, 339.1 mg $O^2{\cdot}kg^{-1}{\cdot}h^{-1}$ and 118.2, 188.2, 252.8 mg $O^2{\cdot}kg^{-1}{\cdot}h^{-1}$ for three of fish used, respectively. Black porgy reared in SW had higher ventilation rates than those in FW. These results indicate that black porgy reared in FW had higher OC than those in SW at the one of fish used, but the fish reared in SW had higher OC than those in FW at the three of fish used.

• Korean Journal of Veterinary Service
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• v.18 no.1
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• pp.1-21
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• 1995

To elucidate pathogenesis of bovine leukemia virus(BLV) in Korean native goats, the goats experimentally infected with BLV were studied especially for the aspects of infectivity and hematological changes. The experimental goats were examined for 27 months by agar-gel immunodiffusion(AGID) test and syncytium formation assay. During this period, changes of total leucocyte, absolute Iymphocyte and atypical Iymphocyte were examined, and the distribution of surface immunoglobulin ( sIg ) -bearing cells and rosette forming cell (RFC) in the peripheral Iymphocyte were also investigated. By indirect immunofluorescence (IFA) and complement dependent antibody cytotoxicity (CDAC) assay using monoclonal antibody(Mab) against bovine leukosis tumor-associated anti-gen(BL-TAA), changes of BL-TAA positive Iymphocyte in peripheral blood were measured. The results obtained through the experiment were summarized as follows. 1. Antibody titers were measured by AGID using gP51 and P24 antigens. The animals were serologically converted at 2 months post-inoculation(pi) in gP51 antigen, whereas sero-converted at 4 months pi in P24 antigen. In comparison with antibody titers for gP51, P24 antigen showed lower titers throughout the trial period. 2. The peripheral lymphocytes from all of the infected goats, as co-cultivated with F8l cells manifested syncytial formation at 4 months pi. 3. On counting total leucocyte, Iymphocyte and atypical Iymphocyte, two out of four infected goats showed normal distribution, while No 2 of the remaining two revealed temporal and No 3, Persistant increasing number of the cells. 4. The optimal condition of rosette formation of the peripheral Iymphocyte of normal Korean native goats was shown in the sheep erythrocyte treated with 0.1M AET for 30 nun at $37^{\circ}C$. When the Iymphocytes were treated in nylon wool column, the number of sIg-bear-ing cell were increased in the nylon wool adherent cells, but RFC was increased in the non-adherent cells. Of the infected goats, No 2 and No 3 showed significantly increasing number of sIg-bearing cells at 18 months pi. 5. The Iymphocytes of No 2 and No 3 goats reacted positively in IFA using Mab against BL-TAA at 12 months pi and 18 months pi, respectively. In CDAC test, all of four infected goats revealed positive reaction at 24 months pi. The higher positive rates were observed in No 2 and No 3 as compared with the remainders.

• Journal of Environmental Policy
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• v.4 no.2
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• pp.83-101
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• 2005

Because of its strong potential for health hazards, the concentration levels of airborne lead (Pb) have been circumscribed by environmental laws in many countries. In this study, we made a comparative study on the environmental behavior of Pb for the acquisition of its distribution characteristics using data sets collected from major cities in Korea for a period of 6 years (1998 through 2003). According to this study, Pb concentration decreased slowly in most industrialized cities of Koreathroughout the whole study. period. In contrast, such temporal signals were not evident in data sets collected from residential, commercial, and grassland areas. Although seasonal patterns generally exhibited the occurrences of high Pb concentration during the spring, results appear to reflect the influence of Asian Dust (AD) in the springtime. The results of our study clearly indicate that Pb distribution is strongly influencedby source types in relation to their land use patterns. Comparison of our Pb data sets with that of other countries indicates that Pb concentration levels obtained from relatively cleaner districts of Korea are still significantly higher than other countries. The results of this analysis generally indicate that Pb concentrations in most areas are affected by the type and strength of man-made activities. Considering that most areas are affected by a variety of pollutants, continuous efforts are needed to control Pb concentrations in the atmosphere.

• Journal of the Korean Geographical Society
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• v.49 no.6
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• pp.833-848
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• 2014

The assessment of the current and future climate change-induced potential wind energy is an important issue in the planning and operations of wind farm. Here, the authors analyze spatiotemporal characteristics and variabilities of wind energy over Korean Peninsula in the near future (2006-2040) using Representative Concentration Pathway(RCP) scenarios data. In this study, National Institute of Meteorological Research (NIMR) regional climate model HadGEM3-RA based RCP 2.6 and 8.5 scenarios are analyzed. The comparison between ERA-interim and HadGEM3-RA during the period of 1981-2005 indicates that the historical simulation of HadGEM3-RA slightly overestimates (underestimates) the wind energy over the land (ocean). It also shows that interannual and intraseasonal variability of hindcast data is generally larger than those of reanalysis data. The investigation of RCP scenarios based future wind energy presents that future wind energy density will increase over the land and decrease over the ocean. The increase in the wind energy and its variability is particularly significant over the mountains and coastal areas, such as Jeju island in future global warming. More detailed analysis presents that the changes in synoptic conditions over East Asia in future decades can influence on the predicted wind energy abovementioned. It is also suggested that the uncertainty of the predicted future wind energy may increase because of the increase of interannual and intra-annual variability. In conclusion, our results can be used as a background data for devising a plan to develop and operate wind farm over the Korean Peninsula.

• Journal of Broadcast Engineering
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• v.16 no.3
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• pp.510-519
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• 2011

Intra mode decision is a useful coding tool in Distributed Video Coding (DVC) for improving DVC coding efficiency for video sequences having fast motion. A major limitation associated with the existing intra mode decision methods, however, is that its efficiency highly depends on user-specified thresholds or modeling parameters. This paper proposes an entropy-based method to address this problem. The probabilities of intra and Wyner?Ziv (WZ) modes are determined firstly by examining correlation of pixels in spatial and temporal directions. Based on these probabilities, entropy of the intra and the WZ modes are computed. A comparison based on the entropy values decides a coding mode between intra coding and WZ coding without relying on any user-specified thresholds or modeling parameters. Experimental results show its superior rate-distortion performance of improvements of PSNR up to 2 dB against a conventional Wyner?Ziv coding without intra mode decision. Furthermore, since the proposed method does not require any thresholds or modeling parameters from users, it is very attractive for real life applications.

• Journal of Korean Society of Forest Science
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• v.83 no.4
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• pp.441-449
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• 1994

The two reflective channels(red and near infrared spectrum) of advanced very high resolution radiometer(AVHRR) data were used to classify primary vegetation cover types in the Korean Peninsula. From the NOAA-11 satellite data archive of 1991, 27 daytime scenes of relatively minimum cloud coverage were obtained. After the initial radiometric calibration, normalized difference vegetation index(NDVI) was calculated for each of the 27 data sets. Four or five daily NDVI data were then overlaid for each of the six months starting from February to November and the maximum value of NDVI was retained for every pixel location to make a monthly composite. The six bands of monthly NDVI composite were nearly cloud free and used for the computer classification of vegetation cover. Based on the temporal signatures of different vegetation cover types, which were generated by an unsupervised block clustering algorithm, every pixel was classified into one of the six cover type categories. The classification result was evaluated by both qualitative interpretation and quantitative comparison with existing forest statistics. Considering frequent data acquisition, low data cost and volume, and large area coverage, it is believed that AVHRR data are effective for vegetation cover type mapping at regional scale.