• Radiation Oncology Journal
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• v.20 no.3
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• pp.193-198
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• 2002

Purpose : Oligodendrogliomas (ODG) are a rare, slow growing, tumor in the brain, which can be cured by complete surgical resection, but as yet it is not known if postoperative adjuvant radiation therapy (RT) is essential, We analyzed the treatment results of patients with irradiated ODG to investigate the efficacy of RT in terms of survival rates and other influencing prognostic factors. Methods and Materials : Between March 1983 and December 1997, 42 patients with ODG were treated with RT at our hospital. The RT was peformed dally at a dose of $1.8\~2.0\;Gy$, at 5 fractions per week, to a total dose of between 39.6 Gy and 64.8 Gy (mean 53.3 Gy). The ages of the patients ranged between 5 and 62 years, with a median age of 39 years. The mean follow-up period was 63.4 months (8-152 months). The Kaplan-Meier method was used to assess the survival, and 5 year survival rates (5-YSR). Log rank tests and Cox regression analyses were used to define the significance of prognostic factors. Results : The majority of ODG in this study were located in the cerebral hemisphere $(83.3\%)$. ODG are slightly more common in men than women, and commonly occurs in middle age, between the 3rd and 4th decades. It has been recommended that RT is commenced within 4 weeks following surgery (5-YSR; $86\%\;vs.\;49\%;\;p<0.03$). Histologically well differentiated, as opposed to poorly differentiated, tumors were found to have a more favorable prognosis (p<0.02). The actuarial 5-YSR was $65.3\%$ (median survival 90 months). 5-YSR for the various extents of surgical excision, followed by external RT, was superior to that of biopsy only followed by external RT $(69.9\%\;vs.\;25.6\%,\;p<0.01)$. Tumor size and location, overall elapsed irradiation days, age, sex, whole brain irradiation as a course of treatment and chemotherapy, had no influence on the 5-YSR (p>0.05). Conclusion : A local involved field irradiation with conventional fractionation, commencing within 4 weeks following surgical excision of the tumor, was beneficial for the 5-YSR, but a total radiation dose exceeding 60 Gy did not improve the 5-YSR.

• Korean Journal of Remote Sensing
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• v.37 no.6_1
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• pp.1631-1645
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• 2021

This research aims to provide the characteristics of the world's first active lidar sensor Atmospheric Laser Doppler Instrument (ALADIN) wind data and Geostationary Korea Multi Purpose Satellite 2A (GK2A) Atmospheric Motion Vector (AMV) data by comparing two wind data. As a result of comparing the data from September 2019 to August 1, 2020, The total number of collocated data for the AMV (using IR channel) and Mie channel ALADIN data is 177,681 which gives the Root Mean Square Error (RMSE) of 3.73 m/s and the correlation coefficient is 0.98. For a more detailed analysis, Comparison result considering altitude and latitude, the Normalized Root Mean Squared Error (NRMSE) is 0.2-0.3 at most latitude bands. However, the upper and middle layers in the lower latitudes and the lower layer in the southern hemispheric are larger than 0.4 at specific latitudes. These results are the same for the water vapor channel and the visible channel regardless of the season, and the channel-specific and seasonal characteristics do not appear prominently. Furthermore, as a result of analyzing the distribution of clouds in the latitude band with a large difference between the two wind data, Cirrus or cumulus clouds, which can lower the accuracy of height assignment of AMV, are distributed more than at other latitude bands. Accordingly, it is suggested that ALADIN wind data in the southern hemisphere and low latitude band, where the error of the AMV is large, can have a positive effect on the numerical forecast model.

• Korean Journal of Remote Sensing
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• v.35 no.3
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• pp.415-431
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• 2019

The satellite-viewed cloudiness, a ratio of cloudy pixels to total pixels ($C_{sat,\;prev}$), inevitably differs from the "ground-viewed" cloudiness ($C_{grd}$) due to different viewpoints. Here we develop an algorithm to retrieve the satellite-viewed, but adjusted cloudiness to $C_{grd} (C_{sat,\;adj})$. The key process of the algorithm is to convert the cloudiness projected on the plane surface into the cloudiness on the celestial hemisphere from the observer. For this conversion, the supplementary satellite retrievals such as cloud detection and cloud top pressure are used as they provide locations of cloudy pixels and cloud base height information, respectively. The algorithm is tested for Himawari-8 level 1B data. The $C_{sat,\;adj}$ and $C_{sat,\;prev}$ are retrieved and validated with $C_{grd}$ of SYNOP station over Korea (22 stations) and China (724 stations) during only daytime for the first seven days of every month from July 2016 to June 2017. As results, the mean error of $C_{sat,\;adj}$ (0.61) is less that than that of $C_{sat,\;prev}$ (1.01). The percent of detection for 'Cloudy' scenario of $C_{sat,\;adj}$ (73%) is higher than that of $C_{sat,\;prev}$ (60%) The percent of correction, the accuracy, of $C_{sat,\;adj}$ is 61%, while that of $C_{sat,\;prev}$ is 55% for all seasons. For the December-January-February period when cloudy pixels are readily overestimated, the proportion of correction of $C_{sat,\;adj$ is 60%, while that of $C_{sat,\;prev}$ is 56%. Therefore, we conclude that the present algorithm can effectively get the satellite cloudiness near to the ground-viewed cloudiness.

• Atmosphere
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• v.32 no.2
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• pp.87-101
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• 2022

In this paper, the performance improvement for the new KMA's Climate Prediction System (GloSea6), which has been built and tested in 2021, is presented by assessing the bias distribution of basic variables from 24 years of GloSea6 hindcasts. Along with the upgrade from GloSea5 to GloSea6, the performance of GloSea6 can be regarded as notable in many respects: improvements in (i) negative bias of geopotential height over the tropical and mid-latitude troposphere and over polar stratosphere in boreal summer; (ii) cold bias of tropospheric temperature; (iii) underestimation of mid-latitude jets; (iv) dry bias in the lower troposphere; (v) cold tongue bias in the equatorial SST and the warm bias of Southern Ocean, suggesting the potential of improvements to the major climate variability in GloSea6. The warm surface temperature in the northern hemisphere continent in summer is eliminated by using CDF-matched soil-moisture initials. However, the cold bias in high latitude snow-covered area in winter still needs to be improved in the future. The intensification of the westerly winds of the summer Asian monsoon and the weakening of the northwest Pacific high, which are considered to be major errors in the GloSea system, had not been significantly improved. However, both the use of increased number of ensembles and the initial conditions at the closest initial dates reveals possibility to improve these biases. It is also noted that the effect of ensemble expansion mainly contributes to the improvement of annual variability over high latitudes and polar regions.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.3
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• pp.192-200
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• 2008

To evaluate the hemodynamic changes and the predictive factors of the clinical outcome in pediatric patients with moyamoya disease, we analyzed pre/post basal/acetazolamide stress brain perfusion SPECT with automated volume of interest (VOIs) method. Methods: Total fifty six (M:F = 33:24, age $6.7{\pm}3.2$ years) pediatric patients with moyamoya disease, who underwent basal/acetazolamide stress brain perfusion SPECT within 6 before and after revascularization surgery (encephalo-duro-arterio-synangiosis (EDAS) with frontal encephalo-galeo-synangiosis (EGS) and EDAS only followed on contralateral hemisphere), and followed-up more than 6 months after post-operative SPECT, were included. A mean follow-up period after post-operative SPECT was $33{\pm}21$ months. Each patient's SPECT image was spatially normalized to Korean template with the SPM2. For the regional count normalization, the count of pons was used as a reference region. The basal/acetazolamide-stressed cerebral blood flow (CBF), the cerebral vascular reserve index (CVRI), and the extent of area with significantly decreased basal/acetazolamide- stressed rCBF than age-matched normal control were evaluated on both medial frontal, frontal, parietal, occipital lobes, and whole brain in each patient's images. The post-operative clinical outcome was assigned as good, poor according to the presence of transient ischemic attacks and/or fixed neurological deficits by pediatric neurosurgeon. Results: In a paired t-test, basal/acetazolamide-stressed rCBF and the CVRI were significantly improved after revascularization (p<0.05). The significant difference in the pre-operative basal/acetazolamide-stressed rCBF and the CVRI between the hemispheres where EDAS with frontal EGS was performed and their contralateral counterparts where EDAS only was done disappeared after operation (p<0.05). In an independent student t-test, the pre-operative basal rCBF in the medial frontal gyrus, the post-operative CVRI in the frontal lobe and the parietal lobe of the hemispheres with EDAS and frontal EGS, the post-operative CVRI, and ${\Delta}CVRI$ showed a significant difference between patients with a good and poor clinical outcome (p<0.05). In a multivariate logistic regression analysis, the ${\Delta}CVRI$ and the post-operative CVRI of medial frontal gyrus on the hemispheres where EDAS with frontal EGS was performed were the significant predictive factors for the clinical outcome (p =0.002, p =0.015), Conclusion: With probabilistic map, we could objectively evaluate pre/post-operative hemodynamic changes of pediatric patients with moyamoya disease. Specifically the post-operative CVRI and the post-operative CVRI of medial frontal gyrus where EDAS with frontal EGS was done were the significant predictive factors for further clinical outcomes.

• Korean Journal of Ecology and Environment
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• v.36 no.1 s.102
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• pp.21-28
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• 2003

Community composition and functional feeding groups of aquatic insects according to stream order were investigated from the Gapyeong Creek, a typical mid-sized Korean stream in Gyeonggi -do, Korea, in April 2000. For field investigations, the main watercourse and three major tributaries of the stream that belong to stream order ll to Vll were divided into reaches (ca. $1{\sim}4$ km in distance). Aquatic insects were sampled from one or two sites each reach (total 30 sites) using a Surber sampler ($50{\times}50$cm, mesh 0.75 mm). As a result of the quantitative samplings(two Surber samplings at riffle and pool/run per site; total $2{\times}30$=60 Surber samplings) and additional qualitative samplings, a total of 164 species of aquatic insects in 103 genera, 54 families, and 8 orders were collected from the stream. Those aquatic insects were composed of Trichoptera (56spp.: 34.1%), Ephemeroptera (43 spp.: 26.2%), Diptera (25spp.: 15.2%), Plecoptera (23 spp.: 14.0%), Coleoptera (6 spp.: 3.7%), Odonata (6 spp.:3.7%), Hemiptera (3 spp.: 1.8%), and Megaloptera (2 spp.: 1.2%); EPT-group (122 spp.:74.4%) or EPT-group plus Diptera (147 spp.: 89.6%) occupied most of the aquatic insect community; relatively larger number of species occurred in the mid-stream reaches (order III-Vl). The quantitative samplings throughout the study sites yielded a total of 26,286 individuals of aquatic insects ($136{\sim}2522$ inds./0.5 $m^2$, mean 906.4inds./0.5 $m^2$) that belongs to Ephemeroptera (11,994 inds.: 45.6%), Diptera (8730 inds.:33.2%), Trichoptera (4123 inds.: 15.7%), Plecoptera (1213 inds.: 4.6%), Coleoptera (204 inds.: 0.8%), Odonata (13 inds.: 0.05%), Megaloptera (5 inds.: 0.02%), and Hemiptera (4inds.: inds.: 0.02%); average number of individuals of aquatic insects increased as the stream order increased: average numbers of individuals of Bllecoptera and Trichoptera decreased and increased, respectively, as the stream order increased. Tolerant species such as Chironomidae spp., Uracanthella rufa and Hydropsychidae spp. were particularly abundant in the down stream reaches (order Vll) . Species diversity indices (H`) and dominance indices (Dl) were relatively higher and lower, respectively, in the mid-stream reaches (order $IV{\sim}VI$). Shredders occupied the smallest partand collector-gatherers were most abundant among the functional feeding groups(FFGs); collector-filterers considerably increased in the down stream reaches (orders Vl and VII); scrappers were relatively evenly distributed throughout the stream reaches: predators were relatively more abundant in the uppermost stream reaches(order ll) . Overall, the characteristics of aquatic insect comminity and FFGs in the Gapyeong Creek are largely similar to those in the normal streams of temperate deciduous forest in the northern hemisphere that is explained by the river confineum concept.