• Clinical and Experimental Pediatrics
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• v.45 no.12
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• pp.1559-1570
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• 2002

Purpose : There has been no exact answer to the question of when to discontinue antiepileptic drugs(AEDs) in children with well-controlled epilepsy for a long period. This study is about the risk factors of relapse after withdrawal of AEDs in seizure(Sz)-free patients to show a guideline for discontinuation of AEDs. Methods : One hundred and sixty-nine children were diagnosed as epileptic at the Pediatric Dept. of Kyung-Hee Univ. between 1993 to 1998, in whom AEDs had been withdrawn after at least two years of Sz-free period. Univariate analysis using Kaplan-Meier survival analysis and multivariate analysis using Cox-proportional hazard model were performed for sixteen risk factors. Results : Forty-nine of the 169 patients(28.9%) had recurrence of Szs. The mean follow-up after withdrawal of AEDs was 4.1 years, mean treatment period was 4.1 years, and the mean Sz-free period was 3.3 years. Factors associated with an increased risk of relapse were young age at onset, symptomatic Sz, Sz type in West and Lennox-Gastaut syndrome, neurologic deficit, longer Sz-controlling period, shorter total treatment period, number of AEDs used(more than one drug), age at withdrawal of AEDs, and Sz-free period less than two years in univariate analysis using Kaplan-Meier mothod. From multivariate analysis, the factors indicating a significantly higher relapse risk were pre-treatment period after first Sz attack, Sz-controlling period, Sz-free period, number of AEDs used, neurologic abnormalities. Conclusion : For epileptic children who were Sz-free for more than two years, and were more than six-years-old, the discontinuation of AEDs should be considered positively, according to age of onset, Sz type, age at withdrawal of AEDs, total treatment period, Sz-controlling period, number of AEDs used, etiology, neurologic deficit, and the wishes of the patients and the their parents.

• The Journal of Korean Society for Radiation Therapy
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• v.22 no.2
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• pp.75-83
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• 2010

Purpose: It aims to evaluate the location change and tendency of hepatic and intrahepatic tumors according to gastric volume and change of location. Materials and Methods: It studied 9 patients with hepatic tumors who visited Gangnam Severance Hospital from March 2009 to April 2010 and who underwent CT or PET (Positron Emission Tomography) within 2 weeks before CT-simulation. The patients fasted for 6 hours before CT-simulation and drank 240~250 cc of water just before CT or PET for image fusion. Those two types of images were fused to RTP (Radiation Treatment Planning, Pinnacle 8.0h) focusing on bone structure of individual patients. Results: They drank 240~260 cc of water but their stomach volume after drinking water varied from 259.3 cc to 495.4 cc. Even though individual differences existed in the change of stomach volume before and after drinking water, the volume was increased by 130 cc (174%) on average. The change in absolute distance between the centers of tumors ranged from 0.52 cm to 3.04 cm (1.52 cm on average); from 0.1 cm to 1.35 cm (0.44 cm on average) in cranial-caudal direction; from 0.05 cm to 2.75 cm (1.22 cm on average) in left-right direction; and from 0.05 cm to 1.85 cm (0.33 cm on average) in ventral-dorsal direction. Conclusion: It is hard to predict the movement of tumors by observing stomach movement, due to great individual differences; however, it was observed that the location of hepatic tumors was right-sided as the stomach was filled with water. Thus, it is recommended to maintain the fastened state to secure the accuracy of hepatic tumor treatment. If it cannot maintain the fastened state, it is recommended to measure stomach volumes and movement in the patient to consider the movement of hepatic tumors before radiation treatment.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.23 no.8
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• pp.759-769
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• 2013

Electronic equipment has been applied to virtually every area associated with commercial, industrial, and military applications. Specifically, electronics have been incorporated into avionics components installed in aircraft. This equipment is exposed to dynamic loads such as vibration, shock, and acceleration. Especially, avionics components installed in a helicopter are subjected to simultaneous sine and random base excitations. These are denoted as sine on random vibrations according to MIL-STD-810F, Method 514.5. In the past, isolators have been applied to avionics components to reduce vibration and shock. However, an isolator applied to an avionics component installed in a helicopter can amplify the vibration magnitude, and damage the chassis, circuit card assembly, and the isolator itself via resonance at low-frequency sinusoidal vibrations. The objective of this study is to investigate the dynamic characteristics of an avionics component installed in a helicopter and the structural dynamic modification of its tray plate without an isolator using both a finite element analysis and experiments. The structure is optimized by dynamic loads that are selected by comparing the vibration, shock, and acceleration loads using vibration and shock response spectra. A finite element model(FEM) was constructed using a simplified geometry and valid element types that reflect the dynamic characteristics. The FEM was verified by an experimental modal analysis. Design parameters were extracted and selected to modify the structural dynamics using topology optimization, and design of experiments(DOE). A prototype of a modified model was constructed and its feasibility was evaluated using an FEM and a performance test.

• Journal of the Korean Society of Radiology
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• v.9 no.2
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• pp.101-107
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• 2015

In anteroposterior radiation test for cervical vertebra, it is general that the incidence angle of X-ray is $15^{\circ}$ to $20^{\circ}$ degrees to head regardless of position. So this study suggests appropriate incidence angle of cervical vertebra depended on the position. From 1 January 2013 to 31 December 2013, cervical spine radiographys and magnetic resonance imaging was performed in 107 people who visited P Hospital located in Pusan. Among them, 39 people(men 24, women 15) were below 80 above 20 years old(average age 54 years) with normal cervical lordosis(normal $40^{\circ}{\pm}5^{\circ}$). In erect position, the incidence angle of cervical vertebra is measured from lateral radiographic images. And in supine position, it measured from MRI sagittal images. Results based on gender, the incidence angle of cervical vertebra in erect position was $25.9^{\circ}$ for men, women was $23.1^{\circ}$, showed statistically significant (p<0.05). And the angle in supine was $11.6^{\circ}$ for men, women was $12.6^{\circ}$, showed not statistically significant (p>0.05) An analysis of age group shows, the incidence angle of cervical vertebra in erect position was $24.6^{\circ}$ under 50, and $25.0^{\circ}$ over 50. The angle in supine was $12.0^{\circ}$ under 50, and $11.9^{\circ}$ over 50. And all of them showed not statistically significant (p>0.05). At all ages, the average of incidence angles in erect position were $24.8^{\circ}$, and the angle in supine was $12.0^{\circ}$, showed statistically significant (p<0.05). The cervical vertebra incidence angle for X-ray was $15^{\circ}$ to $20^{\circ}$ degrees to head in general. But, through the results, it is recommended that the angle is $24.8^{\circ}$ in erect and $12.0^{\circ}$ in supine position. It could be shown true anteroposterior(AP) view of cervical vertebra and accurate intervertebral fusion fixing devices.

• The Korean Journal of Nuclear Medicine
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• v.32 no.3
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• pp.259-265
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• 1998

Purpose: We studied early rest/24 hour delay T1-201 perfusion SPECT for prediction of wall motion improvement after reperfusion in patients with acute myocardial infarction. Materials and Methods: Among 17 patients (male/female= 11/6, age: $59{\pm}13$) with acute myocardial infarction, 15 patients were treated with percutaneous transcoronary angioplasty (direct:2, delay: 11) and intravenous urokinase (2). Spontaneous resolution occurred in infarct-related arteries of 2 patients. We confirmed TIMI 3 flow of infarct-related artery after reperfusion in all patients with coronary angiography. We performed rest T1-201 perfusion SPECT less then 6 hours after reperfusion and delay T1-201 perfusion SPECT next day. T1-201 uptake was visually graded as 4 point score from normal (0) to severe defect (3). Rest T1-201 uptake ${\le}2$ or combination of rest T1-201 uptake ${\le}2$ or late reversibility were considered to be viable. Myocardial wall motion was graded as 5 point score from normal (1) to dyskinesia (5). Myocardial wall motion was considered to be improved when a segment showed an improvement ${\ge} 1$ grade in follow up echo compared with the baseline values. Results: Among 98 segments with wall motion abnormality, the severity of myocardial wall motion decrease was as follow: mild hypokinesia: 18/98 (18%), severe hypokinesia: 28/98 (29%), akinesia: 51/98 (52%), dyskinesia: 1/98 (1%). The wall motion improved in 85%. Redistribution (13%), and reverse redistribution (4%) were observed in 24 hour delay SPECT. Positive predictive value (PPV) and negative predictive value (NPV) of combination of late reversibility and rest T1-201 uptake were 99%, and 54%. PPV and NPV of rest T1-201 uptake were 100% and 52% respectively. Predictive values of combination of rest T1-201 uptake and late reversibility were not significantly different compared with predictive values of rest T1-201 uptake only. Conclusion: We conclude that early T1-201 perfusion SPECT predict myocardial wall motion improvement with excellent positive but relatively low negative predictive values in patients with acute myocardial infarction after reperfusion.

• Korean Journal of Remote Sensing
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• v.31 no.5
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• pp.449-459
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• 2015

The conventional National Forest Inventory(NFI)-based forest carbon stock estimation method is suitable for national-scale estimation, but is not for regional-scale estimation due to the lack of NFI plots. In this study, for the purpose of regional-scale carbon stock estimation, we created grid-based forest carbon stock maps using spatial ancillary data and two types of up-scaling methods. Chungnam province was chosen to represent the study area and for which the $5^{th}$ NFI (2006~2009) data was collected. The first method (method 1) selects forest type map as ancillary data and uses regression model for forest carbon stock estimation, whereas the second method (method 2) uses satellite imagery and k-Nearest Neighbor(k-NN) algorithm. Additionally, in order to consider uncertainty effects, the final AGB carbon stock maps were generated by performing 200 iterative processes with Monte Carlo simulation. As a result, compared to the NFI-based estimation(21,136,911 tonC), the total carbon stock was over-estimated by method 1(22,948,151 tonC), but was under-estimated by method 2(19,750,315 tonC). In the paired T-test with 186 independent data, the average carbon stock estimation by the NFI-based method was statistically different from method2(p<0.01), but was not different from method1(p>0.01). In particular, by means of Monte Carlo simulation, it was found that the smoothing effect of k-NN algorithm and mis-registration error between NFI plots and satellite image can lead to large uncertainty in carbon stock estimation. Although method 1 was found suitable for carbon stock estimation of forest stands that feature heterogeneous trees in Korea, satellite-based method is still in demand to provide periodic estimates of un-investigated, large forest area. In these respects, future work will focus on spatial and temporal extent of study area and robust carbon stock estimation with various satellite images and estimation methods.

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.2
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• pp.103-109
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• 2009

Soils originated from limestone, located at the southern part of Kangwon province and Jecheon, Danyang of Chungbuk province are mainly composed of fine texture, and have different properties from soils originated from granite and granite gneiss, especially for water movement. This study was conducted for classification of hydrologic soil group (HSG) of soils originated from limestone by measuring the infiltration rate of surface soils and percolation rate of sub soils. Soils used for the experiment were 6 soils in total : Gwarim, Mosan, Jangseong, Maji, Anmi and Pyongan series. Infiltration and percolation rate were measured by a disc tension infiltrometer and a Guelph permeameter, respectively. Particle size distribution and organic matter content of the soils were analyzed. HSG, which was made by USDA NRCS(National Resources Conservation Service) for hydrology, of Gwarim series with O horizon of accumulated organic matter was classified as type A which show the properties of low runoff potential, rapid infiltration and percolation rate. HSG of Mosan series, which has high gravel content and very rapid permeability, was classified as type B/D because of the impermaeble base rock layer under 50cm from surface. HSG of Jangseong series with shallow soil depth was classified as type C/D owing to the impermaeble base rock layer under 50cm from surface. HSG of Maji series was type B, and HSG of Anmi series used as paddy land was type D because of slow infiltration and percolation rate caused by the disturbance of surface soil by puddling. HSG of Pyeongan series having a sudden change of layer in soil texture was type D because of the slow percolation rate caused a the layer.

• Korean Journal of Microbiology
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• v.44 no.3
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• pp.237-243
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• 2008

Chemical and microbial characteristics of bacterial populations were investigated in a quercus and pine humus forest soil. Soil pH was $5.3\pm0.4$ and $4.1\pm0.9$ from each sample of a quercus and pine humus forest soil; C/N ratio of humus forest soil was $17.84\pm4.6%$ and $21.76\pm8%$, respectively. Total organic acid was investigated as 69.57 mM/g dry soil and 53.72 mM/g dry soil in each humus forest soil. Glutamine, pyruvate, succinate, lactic acid and acetic acid of pine humus forest soil were $1.5\sim4.5$ times higher than those of quercus humus forest soil. As we evaluated phylogenetic characteristics of bacterial populations by 16S rRNA-ARDRA analysis with DNA extracted from each humus forest soil. Based on the 16S rRNA sequences, 44 clone from ARDRA groups of quercus humus forest soil were classified into 7 phyla: ${\alpha},{\beta},{\gamma},{\delta}$-Proteobacteria, Acidobacteria, Actinobacteria, and Firmicutes. Thirty-two clone from ARDRA groups of pine humus forest soil were classified into 8 phyla: ${\alpha},{\beta},{\gamma}$-Proteobacteria, Acidobacteria, Bacteroides, Verrucomicrobia, Planctomycetes, and Gemmatomonadetes. According to PCA (Principal Component Analysis) based on 16S rRNA base sequence, there were three main groups of bacteria. All clone of Cluster I were originated from quercus humus forest soil, while 67% clone of Cluster II and 63% clone of Clusters III were separated from pine humus forest soil.

• Journal of Animal Science and Technology
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• v.47 no.5
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• pp.703-710
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• 2005

Data from Hanwoo steers and bull calves were analyzed to see the phenotypic and genetic relationships between carcass traits from four different covariance models. Four models fit test station and test period as fixed effect of contemporary group and sire as random effect assuming paternal half-sib relationships among animals. Each model fits one of linear covariate (s) of different slaughter end points-age at slaughter in the first order, age at slaughter in the first and second order, slaughter weight or back fat thickness at 12-13th rib of cold carcass. Age at slaughter in its second order was not significant. Age at slaughter accounted for signifi- cant amount of genetic variances and covariances of carcass traits. Heritability estimates of back fat thickness, rib eye area, carcass weight, marbling score and dressing percentage were 0.34, 0.22, 0.24, 0.42 and 0.18, respectively at constant age basis. The genetic correlation between carcass weight and the other variables were all positive and low to high in magnitude. Genetic correlations between back fat thickness and rib eye area and between marbling score and dressing percentage were low but negative. Variance and covariance structure between these traits were shifted to a great extent when these variables were regressed on slaughter weight or on back fat thickness. These two covariates counteracted to each other but they adjusted each carcass variable or their interrelationship according to differential growth of body components, bone, muscle and fat. Slaughter weight tended to decrease genetic variances and covariances of carcass weight and between component traits and back fat thickness tended to increase those of rib eye area and between rib eye area and carcass weight.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.6 no.4
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• pp.357-368
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• 2008

On July 31, 2008, the Government issued the construction and operation permit for the first low and intermediate level radioactive waste disposal facility in the Republic of Korea. In this paper, the fundamental regulatory framework, regulatory requirements and technical standards of the disposal facility are introduced, and the phased review process adopted for evaluation of the safety of the facility is briefly described. The Atomic Energy Act sets forth a stepwise regulatory framework for the whole life-cycle of the disposal facility such as siting, design, construction, operation, closure and institutional control. More detailed regulatory requirements and technical standards are stipulated in the subsequent regulations of the Atomic Energy Act and a series of Notices issued by the Ministry of Eduction, Science and Technology. The Korea Institute of Nuclear Safety, as entrusted by the Ministry under the Atomic Energy Act, conducted safety review on the disposal facility, and evaluated the compliance with relevant criteria in all technical elements(i.e. siting and structural safety, radiological environmental impact, operational safety, systems and components, quality assurance, and total systematic performance assessment, etc.). The overall safety review process can be phased into inception phase, initial review phase, main review phase and completion phase. The review results were reported to and deliberated by the five Sub-committees of the Special Committee on Nuclear Safety, and then reported to the Ministry. The Ministry issued the construction and operation permit of the disposal facility through the deliberation of the review results by the Nuclear Safety Commission. Hereafter, the safety of the repository will be reassured by a series of subsequent regulatory inspections and reviews under the Atomic Energy Act. In addition, the licensee's continuous implementation of the "Safety Promotion Plan" may also enhance the long-term safety of the repository and contribute to build-up the confidence of the safety case.