• Proceedings of the Korea Water Resources Association Conference
• /
• 2020.06a
• /
• pp.59-59
• /
• 2020

온실가스 증가로 전구평균기온은 지속적으로 상승하고 있으며, 이러한 지구시스템 변화는 수자원의 시·공간적인 변동을 증대시킬 것으로 전망된다. 보다 적극적인 기후변화 대응을 위해 2015년 파리협정이 채택됨에 따라 전 세계에서는 온실가스 감축을 실천하고 있으며, 선진국에서는 산업화 이전 대비 1.5℃ 및 2.0℃ 전구기온상승에 따른 분야별 영향평가 및 적응방안을 마련하고 있다. 그러나 국내의 경우 아직까지 전구기온 상승에 따른 수자원 영향평가가 미흡한 실정이다. 본 연구에서는 AR5 기후변화 시나리오를 기반으로 1.5℃ 및 2.0℃ 전구기온 상승으로 인한 국내 수자원 변화 특성을 분석하였다. 이를 위해 몬순특성을 고려하여 적정 5 GCMs을 선정하였으며, 시간샘플링 기법을 활용하여 1.5℃ 및 2.0℃ 전구기온 상승시기를 추정하였다. 통계적상세화 기법을 적용하여 상세 기후변화 시나리오를 생산하고, 수문모형(VIC)에 적용하여 미래 수문변화를 전망하였다. 과거 대비 1.5℃, 2.0℃ 전구기온 상승에 따른 수문기상인자의 변화를 분석한 결과 연평균 강수량 및 유출량은 전구기온상승에 따라 증가하며, 계절별 변동성은 심화될 것으로 전망되었다. 유출량의 변화는 강수량 변화경향과 대체로 일치하였으나, 강수량 대비 전망결과의 불확실성이 크게 나타났다. 한편, 수문순환은 전 지역에서 가속화되는 것으로 확인되었으며, 모든 GCM의 전망결과에서 동일한 경향을 보였다. 수문기상인자(강수량, 증발산량, 유출량)의 강도별 발생빈도 및 총량은 저강도 구간에서 감소, 고강도 구간에서 증가하는 것으로 분석되었다. 이러한 특성은 강수량 및 유출량의 극대값 증가에 기여하여 수자원 관리의 어려움을 가중시킬 것으로 예상된다.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2022.05a
• /
• pp.361-361
• /
• 2022

최근 기후변화의 영향으로 국지성 집중호우에 의한 홍수 피해가 빈번히 발생하고 있으며, 이로 인한 인명 및 재산 피해가 증가하고 있다. 2020년의 경우, 최장 기간 장마로 인해 금강유역을 비롯한 전국에서 산사태, 제방 붕괴, 침수 등 많은 피해가 발생하였다. 이러한 홍수피해 저감을 위해서는 신뢰도 높은 홍수량 예측이 요구된다. 특히, 토양수분과 같이 시간에 따른 유역 수문 정보를 모의 과정에서 고려하는 것이 매우 중요하다. 아울러, 유역 전반에 대한 토양수분 정보는 실시간으로 획득하는 것이 어려워 이를 고려할 수 있는 강우-유출모형을 활용하는 것이 바람직하다. 이러한 수문모형으로 SURR(Sejong University Rainfall Runoff) 모형이 있으며 다양한 적용 및 평가를 통해 모형 활용성에 대한 증진이 요구되는 실정이다. 본 연구에서는 저류함수 기반의 시단위 연속형 강우-유출모형(SURR 모형)을 활용한 강우-유출 모의를 수행하여 홍수 피해가 컸던 금강유역을 대상으로 모형의 적용성을 평가하고자 한다. 평가기간은 2006~2020년으로써 유량관측 지점별 매개변수 검·보정을 수행하였다. 관측 및 모의 유량에 대한 도시적 및 통계적(CC, RMSE, NSE) 평가를 수행하여 유출 모의에 대한 정확도를 평가하였다. 평가결과, 관측 및 모의 유량 간의 거동이 유사한 것으로 나타났으며 첨두유량 및 시간이 비교적 잘 일치하는 것으로 나타나 대상유역의 신뢰도 높은 유출량을 모의하는데 적합한 것으로 확인되었다. 본 연구 결과는 향후 AI 기법과 연계한 돌발홍수 예측 연구에 활용하여 정확도 높은 유역 홍수량 예측 및 선행시간 확보에 도움이 될 것으로 기대된다.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.27 no.3
• /
• pp.239-249
• /
• 2001

The purpose of this study is to evaluate the relationship of the factors which could be influenced by orthognathic surgery especillay SSRO. We measured the amounts of the maximum opening, lateral movements, maximum velocity and pattern of mandibular path during the opening and closing of mandible at the following times ; preoperative, 1 month after operation, 6 months after operation respectively using MKG. And the results were compared according to the categorized subgroups. Following results were obtained : 1. The change of the amounts of mandibular lateral movement and maximum opening velocity were statistically different between male and female (p<0.05), but the others were not. 2. According to the method of operation, there was no difference in the change of the mandibular movements between the group of SSRO and SSRO plus LeFort I osteotomy (p>0.05). 3. According to the amounts of mandibular movement, the recovery of left lateral movement of the group of $6{\sim}10mm$ was better than the other groups (p<0.05). 4. In the frontal pattern of the opening and closing of the mandible, the complex deflected type (F5), simple deflected type (F4), complex deviated type (F3), simple deviated type (F2), straight type (F1) were obtained in order at the time of preoperative, simple deflected type, simple deviated type, complex deviated type, straight type, complex deflected type in order at the time of 1 month after surgery, and the result at the time of 6 months after surgery was the same with that of the time of preoperative. In the sagittal pattern, non-coincident type (S2) was predominant at the time of preoperative, and coincident type (S1) was predominant at the time of 1 month after surgery. After 6 months, the result was also the same with that of the preoperative in sagittal pattern. 5. There was not a statistical difference in the change of the mandibular movement between group of presence of the preoperative TMJ symptoms and non-presence group (p>0.05). 6. There was not a statistical difference in the change of the mandibular movement between repositioning device applied group and non-applied group (p>0.05). 7. Sixty three percents of the patients who had preoperative TMJ symptoms were improved after surgery and preoperative TMJ symptoms were more improved after operation in the repositioning device non-applied group statistically (p<0.05).

• Journal of the Korean Society of Radiology
• /
• v.11 no.5
• /
• pp.303-312
• /
• 2017

The central goal of Gamma Knife radiosurgery(GKRS) is to maximize the conformity of the prescription isodose surface, and to minimize the radiation effect of the normal tissue surrounding the target volume. There are the various kinds of indices related with the quality of treatment plans such as conformity index, coverage, selectivity, beam-on time, gradient index(GI), and conformity/gradient index(CGI). As the best treatment plan evaluation tool, we must check by all means conformity index, GI, and CGI among them. Specially, GI and CGI related with complication of healthy normal tissue is more indispensible than conformity index. Then author calculated and statistically analysed CGI, the newly defined conformity/gradient index as well as GI being applied widely using the treatment planning system Leksell GammaPlan(LGP) and the verification method Variable Ellipsoid Modeling Technique(VEMT). In the study 10 patients with intracranial lesion treated by GKRS were included. Author computed the indices from LGP and VEMT requiring only four parameters: the prescribed isodose volume, the volume with dose > 30%, the target volume, and the volume of half the prescription isodose. All data were analyzed by paired t-test, which is statistical method used to compare two different measurement techniques. No statistical significance in GI at 10 cases was observed between LGP and VEMT. Differences in GI ranged from -0.14 to 0.01. The newly defined gradient index calculated by two methods LGP and VEMT was not statistically significant either. Author did not find out the statistical difference for the prescribed isodose volume between LGP and VEMT. CGI as the evaluation index for determining the best treatment plan is not significant statistically also. Differences in CGI ranged from -4 to 3. Similarly newly defined Conformity/Gradient index for GKRS was also estimated as the metric for the evaluation of the treatment plans through statistical analysis. Statistical analyses demonstrated that VEMT was in excellent agreement with LGP when considering GI, new gradient index, CGI, and new CGI for evaluating the best plans of GKRS. Due to the application of the fast and easy evaluation tool through LGP and VEMT author hopes CGI and newly defined CGI as well as gradient indices will be widely used.

• Journal of Korean Society of Forest Science
• /
• v.98 no.3
• /
• pp.215-224
• /
• 2009

A review was given of the role of traditional morphometrics in plant morphological studies using 54 published studies in three major journals and others in Korea, such as Journal of Korean Forestry Society, Korean Journal of Plant Taxonomy, Korean Journal of Breeding, Korean Journal of Apiculture, Journal of Life Science, and Korean Journal of Plant Resources from 1997 to 2008. The two most commonly used techniques of data analysis, cluster analysis (CA) and principal components analysis (PCA) with other statistical tests were discussed. The common problem of PCA is the underlying assumptions of methods, like random sampling and multivariate normal distribution of data. The procedure was intended mainly for continuous data and was not efficient for data which were not well summarized by variances or covariances. Likewise CA was most appropriate for categorical rather than continuous data. Also, the CA produced clusters whether or not natural groupings existed, and the results depended on both the similarity measure chosen and the algorithm used for clustering. An additional problems of the PCA and the CA arised with both qualitative and quantitative data with a limited number of variables and/or too few numbers of samples. Some of these problems may be avoided if a certain number of variables (more than 20 at least) and sufficient samples (40-50 at least) are considered for morphometric analyses, but we do not think that the methods are all mighty tools for data analysts. Instead, we do believe that reasonable applications combined with focus on objectives and limitations of each procedure would be a step forward.

• The Korean Journal of Nuclear Medicine
• /
• v.32 no.3
• /
• pp.225-237
• /
• 1998

Purpose: We investigated the statistical methods to compose the functional brain map of human working memory and the principal factors that have an effect on the methods for localization. Materials and Methods: Repeated PET scans with successive four tasks, which consist of one control and three different activation tasks, were performed on six right-handed normal volunteers for 2 minutes after bolus injections of 925 MBq $H_2^{15}O$ at the intervals of 30 minutes. Image data were analyzed using SPM96 (Statistical Parametric Mapping) implemented with Matlab (Mathworks Inc., U.S.A.). Images from the same subject were spatially registered and were normalized using linear and nonlinear transformation methods. Significant difference between control and each activation state was estimated at every voxel based on the general linear model. Differences of global counts were removed using analysis of covariance (ANCOVA) with global activity as covariate. Using the mean and variance for each condition which was adjusted using ANCOVA, t-statistics was performed on every voxel To interpret the results more easily, t-values were transformed to the standard Gaussian distribution (Z-score). Results: All the subjects carried out the activation and control tests successfully. Average rate of correct answers was 95%. The numbers of activated blobs were 4 for verbal memory I, 9 for verbal memory II, 9 for visual memory, and 6 for conjunctive activation of these three tasks. The verbal working memory activates predominantly left-sided structures, and the visual memory activates the right hemisphere. Conclusion: We conclude that rCBF PET imaging and statistical parametric mapping method were useful in the localization of the brain regions for verbal and visual working memory.

• Journal of radiological science and technology
• /
• v.37 no.1
• /
• pp.37-47
• /
• 2014

The purpose of this study was to analyze translational and rotational adjustments during automatic rigid image-registration by using different control parameters for a total of five groups on TomoTherapy (Accuray Inc, Sunnyvale, CA, USA). We selected a total of 50 patients and classified them in five groups (brain, head-and-neck, lung, abdomen and pelvic) and used a total of 500 megavoltage computed tomography (MVCT) image sets for the analysis. From this we calculated the overall mean value(M) for systematic and random errors after applying the different control parameters. After randomization of the patients into the five groups, we found that the overall mean value varied according to three techniques and resolutions. The deviation for the lung, abdomen and pelvic groups was approximately greater than the deviation for the brain and head-and-neck groups in all adjustments. Overall, using a "full-image" produces smaller deviations in the rotational adjustments. We found that rotational adjustment has deviations with distinctly different control parameters. We concluded that using a combination of the "full-image" technique and "standard" resolution will be helpful in assisting with patients' repositioning and in correcting for set-up errors prior to radiotherapy on TomoTherapy.

• Geophysics and Geophysical Exploration
• /
• v.9 no.1
• /
• pp.129-138
• /
• 2006

Helicopter-borne aeromagnetic surveys at two different times separated by three years were conducted to better understand the shallow subsurface structure of the Vulcano and Lipari volcanic complex, Aeolian Islands, southern Italy, and also to monitor the volcanic activity of the area. As there was no meaningful difference between the two magnetic datasets to imply an apparent change of the volcanic activity, the datasets were merged to produce an aeromagnetic map with wider coverage than was given by a single dataset. Apparent magnetisation intensity mapping was applied to terrain-corrected magnetic anomalies, and showed local magnetisation highs in and around Fossa Cone, suggesting heterogeneity of the cone. Magnetic modelling was conducted for three of those magnetisation highs. Each model implied the presence of concealed volcanic products overlain by pyroclastic rocks from the Fossa crater. The model for the Fossa crater area suggests a buried trachytic lava flow on the southern edge of the present crater. The magnetic model at Forgia Vecchia suggests that phreatic cones can be interpreted as resulting from a concealed eruptive centre, with thick latitic lavas that fill up Fossa Caldera. However, the distribution of lavas seems to be limited to a smaller area than was expected from drilling results. This can be explained partly by alteration of the lavas by intense hydrothermal activity, as seen at geothermal areas close to Porto Levante. The magnetic model at the north-eastern Fossa Cone implies that thick lavas accumulated as another eruption centre in the early stage of the activity of Fossa. Recent geoelectric surveys showed high-resistivity zones in the areas of the last two magnetic models.

• Pediatric Infection and Vaccine
• /
• v.17 no.2
• /
• pp.101-107
• /
• 2010

Purpose : In evaluation of patients, laboratory results are crucial in determination of a treatment plan. Obtaining venous blood from infants and children is a difficult procedure. Substitution of a capillary blood sample for a venous blood sample has been suggested. However, there are few studies showing mutual correlation between C-reactive protein (CRP) results in capillary and venous blood. This study was designed to determine whether the result of the capillary sample is the same as the result of the venous blood sample. Methods : After informed consent, a pair of venous and fingertip capillary blood samples were simultaneously collected from 100 children. The LC-178CRPTM was used for analysis of capillary blood and the Hitachi 7180 automatic hematology analyzer was used for analysis of venous blood. We compared CRP of both venous and capillary blood samples. Results were analyzed by crosstabulation analysis, simple regression analysis and the Bland Altman Plot method. Results : A close correlation (90.63%) was observed between capillary and venous blood analyzed by crosstabulation analysis. CRP results were similar between the two groups and showed a high coefficient correlation ($\beta$=1.3434, $R^2$=0.9888, P<0.0001) when analyzed by a simple regression model. The average value in venous blood was also higher compared to capillary blood. According to Bland Altman Plot analysis, lab results were measured at a 95% confidence interval. Conclusion : CRP results from capillary blood showed close correlation with venous blood sampling. At present, venous blood sampling is the preferred method. However, due to difficulty in venous blood sampling, capillary sampling could be considered as an alternative technique for use with children.

• The Korean Journal of Nuclear Medicine Technology
• /
• v.20 no.1
• /
• pp.52-58
• /
• 2016

Purpose Recent retrospective studies are being actively conducted to analyze the survival of patients with SUVmax, MTV, TLG, such as information from a variety of PET originating. However, there is no clear way is difficult to accurately measure the volume of the tumor may be the difference between the caster is raised. In this study, to evaluate compare the volume measuring methods according to the characteristics of the tumor. Materials and Methods 18F-saline to fill the NEMA IEC Body Phantom insert the volume of balance and imbalance in phantom were acquired to the Biograph truepoint 40 (Siemens medical system, Germany) PET/CT scanner. The ratio of the volume and Background was acquired as 3.0, 5.0, 8.0, 18, 40. Clinical patients were randomly selected 120 people in staging patients with cancer of the digestive system from the year 2010 until the year 2014. Measurement methods were used a 40% threshold, 50% threshold and gradient segmentation technique, i.e. PET EDGE. Five years of experience of the two radio-technologist and one doctor was measured by repeated three times. Analysis methods were Intraclass correlation coefficient and Pearson correlation. Results In Phantoms, the 40% threshold method gave the best concordance between measured and actual volumes (r = 0.992, 0.997). In clinical patient outcome agreement between observers EDGE it is as high as 0.999 (CI: 0.998-0.999). And there were no statistical significance of the difference between the measurements (P = 0.620). 40% threshold method showed the best correlation between the measurements (r = 0.953). Increasing the ratio of tumor to background decreased the influence of a measuring method. Conclusion How to measure volume of the tumor in the patient was clinically most useful is 50% and the lowest impact on the characteristics of the tumor. Therefore, to reduce the background of the patients in PET/CT scan, it should be required research and effort.