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Seoul National University (seoul + national_university)
Terms modified by Seoul National University Selected AbstractsDaily streamflow modelling and assessment based on the curve-number techniqueHYDROLOGICAL PROCESSES, Issue 16 2002Jin-Yong Choi Abstract A cell-based long-term hydrological model (CELTHYM) that can be integrated with a geographical information system (GIS) was developed to predict continuous stream flow from small agricultural watersheds. The CELTHYM uses a cell-by-cell soil moisture balance approach. For surface runoff estimation, the curve number technique considering soil moisture on a daily basis was used, and release rate was used to estimate baseflow. Evapotranspiration was computed using the FAO modified Penman equation that considered land-use-based crop coefficients, soil moisture and the influence of topography on radiation. A rice paddy field water budget model was also adapted for the specific application of the model to East Asia. Model sensitivity analysis was conducted to obtain operational information about the model calibration parameters. The CELTHYM was calibrated and verified with measured runoff data from the WS#1 and WS#3 watersheds of the Seoul National University, Department of Agricultural Engineering, in Hwaseong County, Kyounggi Province, South Korea. The WS#1 watershed is comprised of about 35·4% rice paddy fields and 42·3% forest, whereas the WS#3 watershed is about 85·0% forest and 11·5% rice paddy fields. The CELTHYM was calibrated for the parameter release rate, K, and soil moisture storage coefficient, STC, and results were compared with the measured runoff data for 1986. The validation results for WS#1 considering all daily stream flow were poor with R2, E2 and RMSE having values of 0·40, ,6·63 and 9·69 (mm), respectively, but validation results for days without rainfall were statistically significant (R2 = 0·66). Results for WS#3 showed good agreement with observed data for all days, and R2, E2 and RMSE were 0·92, 0·91 and 2·23 (mm), respectively, suggesting potential for CELTHYM application to other watersheds. The direct runoff and water balance components for watershed WS#1 with significant areas of paddy fields did not perform well, suggesting that additional study of these components is needed. Copyright © 2002 John Wiley & Sons, Ltd. [source] Preoperative staging of gastric cancer by endoscopic ultrasonography and multidetector-row computed tomographyJOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY, Issue 3 2010Sung Wook Hwang Abstract Background and Aim:, The aim of this study was to determine the accuracy of endoscopic ultrasonography (EUS) and multidetector-row computed tomography (MDCT) for the locoregional staging of gastric cancer. EUS and computed tomography (CT) are valuable tools for the preoperative evaluation of gastric cancer. With the introduction of new therapeutic options and the recent improvements in CT technology, further evaluation of the diagnostic accuracy of EUS and MDCT is needed. Methods:, In total, 277 patients who underwent EUS and MDCT, followed by gastrectomy or endoscopic resection at Bundang Hospital, Seoul National University, from July 2006 to April 2008, were analyzed. The results from the preoperative EUS and MDCT were compared to the postoperative pathological findings. Results:, Among the 277 patients, the overall accuracy of EUS and MDCT for T staging was 74.7% and 76.9%, respectively. Among the 141 patients with visualized primary lesions on MDCT, the overall accuracy of EUS and MDCT for T staging was 61.7% and 63.8%, respectively. The overall accuracy for N staging was 66% and 62.8%, respectively. The performance of EUS and MDCT for large lesions and lesions at the cardia and angle had significantly lower accuracy than that of other groups. For EUS, the early gastric cancer lesions with ulcerative changes had significantly lower accuracy than those without ulcerative changes. Conclusions:, For the preoperative assessment of individual T and N staging in patients with gastric cancer, the accuracy of MDCT was close to that of EUS. Both EUS and MDCT are useful complementary modalities for the locoregional staging of gastric cancer. [source] Lichtmanipulation in plasmonischen KristallenPHYSIK IN UNSERER ZEIT (PHIUZ), Issue 3 2005Claus Ropers Die Energie ultrakurzer Lichtimpulse kann für Zeiten im Femtosekundenbereich in metallischen Nanostrukturen gespeichert werden. Forscher am Max-Born-Institut in Berlin und an der Seoul National University in Korea haben gezeigt, dass die Speicherzeit ein Vielfaches der Impulsdauer betragen und gezielt verändert werden kann. [source] SLA typing using the PCR-SSP method and establishment of the SLA homozygote line in pedigreed SNU miniature pigsANIMAL SCIENCE JOURNAL, Issue 2 2010Su-Cheong YEOM ABSTRACT Seoul National University (SNU) miniature pigs represent a closed colony with 24 founder pigs and a well preserved pedigree. Characterization using mRNA sequence analysis was conducted for 6 swine leukocyte antigen (SLA) loci in parental or founder pigs, and 17 defined alleles were detected. Based on these complete coding sequences, 17 sequence specific primers (SSPs) were designed for polymorphic sites. To validate the specificity of each allele SSP, the PCR-SSP was conducted with defined allele clones as templates. PCR-SSP was conducted with the hot start polymerase and touch-down PCR. The parental or found SNU miniature pigs showed overall SLA class I and II heterozygotes. Using the established PCR-SSP method, we conducted SLA typing for breeding stock including 2 pedigreed pigs and identified the novel SLA class II homozygote haplotye (DRA*0201, DRB1*0403, DQA*0102 and DQB1*0701) and 2 SLA homozygote pig lines: SLA class I Hp-3.0 and class II Hp-0.3, and SLA class I Hp-2.0 and class II Hp-0.2. We thought that our PCR-SSP SLA typing method could be applicable for new SLA homozygote line establishment by assignment and scheduled breeding. [source] Phylogenetic analysis for the Seoul National University (Minnesota) miniature pig by mitochondrial DNA sequence polymorphismANIMAL SCIENCE JOURNAL, Issue 2 2010Su-Cheong YEOM ABSTRACT Seoul National University (SNU) miniature pigs are originated from the Minnesota miniature pig. This study was conducted to investigate the maternal origin of SNU (Minnesota) miniature pigs and their phylogenetic relationships by analyzing the mitochondrial DNA (mtDNA) D-loop (control region) sequence. Two mtDNA D-loop sequences of the SNU miniature pigs were identified. On an unweighted pair-group method with an arithmetic mean (UPGMA) phylogenetic tree analysis, the large white was the pig breed closest to the SNU miniature pig, and the pairwise distance analysis showed the same result. While mtDNA sequences of 4 pig breeds which were used to establish Minnesota miniature pig were not known, our result might be different from the history of the Minnesota miniature pig development. In conclusion, we thought that some haplotypes of the Minnesota miniature pig maternally were originated from the Large white pig, or that wild pigs had similar mtDNA sequences to the Large white pig, and all SNU miniature pigs were derived from this colony. [source] Optimal Moving Angle of Pusher Plate in Occlusive-Type Pulsatile Blood PumpARTIFICIAL ORGANS, Issue 7 2010Hyuk Choi Abstract Since the occlusive-type pulsatile extracorporeal blood pump (Twin-Pulse Life Support System; Seoul National University, Seoul, Korea) received the CE mark of the European Directives and Korea Food and Drug Administration approval (2004) for short-term applications as an extracorporeal life support system, the pump system has been tested for hemolysis. This pump system was recently upgraded with an ameliorated pusher plate to reduce hemolysis. In this study, numerical analysis and in vitro tests were performed to determine the optimal conditions for increasing the durability of the blood sac and pump output. During the simulation, the minimum sliding interface force (SIF) for the angle of the pusher plate movement (PPM) was calculated (40,70°). In the in vitro durability test, the angle of the PPM was increased gradually from 40 to 70° in 10° increments, and the mean time to failure (MTTF) of the blood sac was calculated. Fifteen tests were conducted for each case: 40, 50, 60, and 70° (n = 15 each). The MTTF of the blood sac was defined as the time when a crack of the blood sac occurred. The longer lifetime of the blood sac at 60° of the PPM (297.0 h) than that at 50° (197.6 h) was attributed to the lower SIF value (,0.13, normalized value) at 60° of the PPM. [source] Scientific instrumentation for the 1.6 m New Solar Telescope in Big BearASTRONOMISCHE NACHRICHTEN, Issue 6 2010W. Cao Abstract The NST (New Solar Telescope), a 1.6 m clear aperture, off-axis telescope, is in its commissioning phase at Big Bear Solar Observatory (BBSO). It will be the most capable, largest aperture solar telescope in the US until the 4 m ATST (Advanced Technology Solar Telescope) comes on-line late in the next decade. The NST will be outfitted with state-of-the-art scientific instruments at the Nasmyth focus on the telescope floor and in the Coudé Lab beneath the telescope. At the Nasmyth focus, several filtergraphs already in routine operation have offered high spatial resolution photometry in TiO 706 nm, H, 656 nm, G-band 430 nm and the near infrared (NIR), with the aid of a correlation tracker and image reconstruction system. Also, a Cryogenic Infrared Spectrograph (CYRA) is being developed to supply high signal-to-noise-ratio spectrometry and polarimetry spanning 1.0 to 5.0 ,m. The Coudé Lab instrumentation will include Adaptive Optics (AO), InfraRed Imaging Magnetograph (IRIM), Visible Imaging Magnetograph (VIM), and Fast Imaging Solar Spectrograph (FISS). A 308 sub-aperture (349-actuator deformable mirror) AO system will enable nearly diffraction limited observations over the NST's principal operating wavelengths from 0.4 ,m through 1.7 ,m. IRIM and VIM are Fabry-Pérot based narrow-band tunable filters, which provide high resolution two-dimensional spectroscopic and polarimetric imaging in the NIR and visible respectively. FISS is a collaboration between BBSO and Seoul National University focussing on chromosphere dynamics. This paper reports the up-to-date progress on these instruments including an overview of each instrument and details of the current state of design, integration, calibration and setup/testing on the NST (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] | |||||||||||||