• The Journal of Korean Society for Radiation Therapy
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• v.18 no.1
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• pp.29-34
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• 2006

Purpose: The radioprotective effects of white and fermented ginseng on liver damage induced by $^{60}Co\;{\gamma}$-ray were investigated. Materials and Methods: To one group of ICR male mice were given white(150 mg/kg/day for 7 days, orally) and fermented ginseng(150 mg/kg/day for 7 days, orally) before $^{60}Co\;{\gamma}$-ray irradiation. To another group were irradiated by 5 Gy(1.01 Gy/min) dose of $^{60}Co\;{\gamma}$-ray. Contrast group were given with saline(0.1 mL). The levels of reduced(GSH) and oxidized(GSSG) glutathione in liver tissue were measured. Results: In the fermented(150 mg/kg) and white ginseng(150 mg/kg) groups than irradiation group, the GSH levels were significantly increased, but the GSSG levels were significantly decreased. The ratio of GSSG/total GSH was significantly decreased in the fermented(150 mg/kg) and white ginseng(150 mg/kg) groups than irradiation group. Conclusion: In the fermented(150 mg/kg) groups than white ginseng(150 mg/kg) groups the GSH levels were significantly increased. The radioprotective effects of fermented(150 mg/kg) groups than white ginseng(150 mg/kg) groups were increased.

• Journal of Sensor Science and Technology
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• v.7 no.3
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• pp.147-153
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• 1998

The strain characteristics of a fiber optic Fabry-Perot pressure sensor with high sensitivity using a $Si_{3}N_{4}/SiO_{2}/Si_{3}N_{4}$ (N/O/N) diaphragm is experimentally investigated. A 600 nm thick N/O/N diaphragm was fabricated by silicon anisotropic etching technology in 44 wt% KOH solution. An interferometric fiber optic pressure sensor has been manufactured by using a fiber optic Fabry-Perot intereferometer and a N/O/N diaphragm. The 2 cm length fiber optic Fabry-Perot interferometers in the continuous length of single mode fiber were produced with two pieces of single mode fiber coated with $TiO_{2}$ dielectric film utilizing the fusion splicing technique. The one end of the fiber optic Fabry-Perot interferometer was bonded to a N/O/N diaphragm. and the other end was connected to an optical setup through a 3 dB coupler. For the N/O/N diaphragm sized $2{\times}2\;mm^{2}$ and $8{\times}8\;mm^{2}$, the pressure sensitivity was measured 0.11 rad/kPa and 1.57 rad/kPa, respectively, and both of the nonlinearities were less than 0.2% FS.

• Korean Journal of Radiology
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• v.25 no.2
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• pp.189-198
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• 2024

Objective: To investigate the prognostic utility of radiomics features extracted from ¹⁸F-fluorodeoxyglucose (FDG) PET/CT combined with clinical factors and metabolic parameters in predicting progression-free survival (PFS) and overall survival (OS) in individuals diagnosed with extranodal nasal-type NK/T cell lymphoma (ENKTCL). Materials and Methods: A total of 126 adults with ENKTCL who underwent ¹⁸F-FDG PET/CT examination before treatment were retrospectively included and randomly divided into training (n = 88) and validation cohorts (n = 38) at a ratio of 7:3. Least absolute shrinkage and selection operation Cox regression analysis was used to select the best radiomics features and calculate each patient's radiomics scores (RadPFS and RadOS). Kaplan-Meier curve and Log-rank test were used to compare survival between patient groups risk-stratified by the radiomics scores. Various models to predict PFS and OS were constructed, including clinical, metabolic, clinical + metabolic, and clinical + metabolic + radiomics models. The discriminative ability of each model was evaluated using Harrell's C index. The performance of each model in predicting PFS and OS for 1-, 3-, and 5-years was evaluated using the time-dependent receiver operating characteristic (ROC) curve. Results: Kaplan-Meier curve analysis demonstrated that the radiomics scores effectively identified high- and low-risk patients (all P < 0.05). Multivariable Cox analysis showed that the Ann Arbor stage, maximum standardized uptake value (SUVmax), and RadPFS were independent risk factors associated with PFS. Further, β2-microglobulin, Eastern Cooperative Oncology Group performance status score, SUVmax, and RadOS were independent risk factors for OS. The clinical + metabolic + radiomics model exhibited the greatest discriminative ability for both PFS (Harrell's C-index: 0.805 in the validation cohort) and OS (Harrell's C-index: 0.833 in the validation cohort). The time-dependent ROC analysis indicated that the clinical + metabolic + radiomics model had the best predictive performance. Conclusion: The PET/CT-based clinical + metabolic + radiomics model can enhance prognostication among patients with ENKTCL and may be a non-invasive and efficient risk stratification tool for clinical practice.

• Korean Journal of Radiology
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• v.23 no.9
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• pp.921-930
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• 2022

Objective: To identify epidermal growth factor receptor (EGFR) mutations in lung adenocarcinoma based on ¹⁸F-fluorodeoxyglucose (FDG) PET/CT radiomics and clinical features and to distinguish EGFR exon 19 deletion (19 del) and exon 21 L858R missense (21 L858R) mutations using FDG PET/CT radiomics. Materials and Methods: We retrospectively analyzed 179 patients with lung adenocarcinoma. They were randomly assigned to training (n = 125) and testing (n = 54) cohorts in a 7:3 ratio. A total of 2632 radiomics features were extracted from the tumor region of interest from the PET (1316) and CT (1316) images. Six PET/CT radiomics features that remained after the feature selection step were used to calculate the radiomics model score (rad-score). Subsequently, a combined clinical and radiomics model was constructed based on sex, smoking history, tumor diameter, and rad-score. The performance of the combined model in identifying EGFR mutations was assessed using a receiver operating characteristic (ROC) curve. Furthermore, in a subsample of 99 patients, a PET/CT radiomics model for distinguishing 19 del and 21 L858R EGFR mutational subtypes was established, and its performance was evaluated. Results: The area under the ROC curve (AUROC) and accuracy of the combined clinical and PET/CT radiomics models were 0.882 and 81.6%, respectively, in the training cohort and 0.837 and 74.1%, respectively, in the testing cohort. The AUROC and accuracy of the radiomics model for distinguishing between 19 del and 21 L858R EGFR mutational subtypes were 0.708 and 66.7%, respectively, in the training cohort and 0.652 and 56.7%, respectively, in the testing cohort. Conclusion: The combined clinical and PET/CT radiomics model could identify the EGFR mutational status in lung adenocarcinoma with moderate accuracy. However, distinguishing between EGFR 19 del and 21 L858R mutational subtypes was more challenging using PET/CT radiomics.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.53 no.5
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• pp.305-308
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• 2004

The 7-dial inductive voltage divider(IVD) for application at low frequency range which can precisely divide the in put voltage up to resolution of $10^{-7}$ was fabricated by using the toroidal cores made by super-mumetal strips of 0.025 mm thick and special decade switches. The cores have the initial permeability of 200.000 and magnetic flux density of 0.5 T. The inphase and quadrature ratio errors for a fabricated 7-dial IVD are found to be less than $\pm$4${\times}$$10^{-7}$ and $\pm$5${\times}$$10^{-6}$ rad(k=2), respectively. by calibration using the IVD calibration system of KRISS. The fabrication techniques used and uncertainty evaluation are discussed in this paper.

• Proceedings of the Microbiological Society of Korea Conference
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• 2003.05a
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• pp.55-58
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• 2003

• Korean Journal of Optics and Photonics
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• v.6 no.1
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• pp.70-75
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• 1995

Erbium 첨가 광섬유를 광원겸 광증폭기로 사용하는 방식으로 개회로 형태의 광섬유 gyroscope를 구성하였다. Erbium 첨가 광섬유를 거쳐 5mW 이상의 gyro 출력광 power와 7nm의 파장선폭을 얻었다. Loop 광섬유로부터 광증폭기형 광원으로의 feedback으로 인하여 회전속도에 따라 scale factor가 변화함을 관찰할 수 있었다. 그러나 변조된 gyro 출력신호광의 평균 power가 회전속도에 무관하도록 위상차의 변조진폭을 $\PHI_m=2.405 rad$으로 한 경우에 회전속도와 무관한 일정한 scale factor를 얻을 수 있었다.

• Proceedings of the KIEE Conference
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• 1999.07a
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• pp.284-286
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• 1999

The 7-dial inductive voltage divider (IVD) which is divided the in put voltage precisely upto 10-7 were fabricated by using the toroidal cores made of super-mumetal strips of 0.025 mm thick and special decade switches. The cores ate of the initial permeability of 200,000 and magnetic flux density of 0.5 T. The in phase and quadrature ratio errors are evaluated to less than ${\pm}4{\times}10^{-7}$ and ${\pm}5{\times}10^{-6}$ rad. respectively. The fabrication techniques used are more discussed in this paper.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.4 no.2
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• pp.103-116
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• 2006

By executing corrosion experiment on Inconel 600, 690 used to material of S/G tube in domestic NPP, this paper show estimation of amount of product such as Co-58, Co-60, Cr-51, Mn-54, Fe-59 which are main exposure cause to the workers in NPP. Therefore, Making the 12 samples consisted of Inconel 600, 690, whole corrosion experiment was carried out for 60 days(each pH by 20 days). The conditions of those tests were similar or more harsh than actual conditions of domestic NPP. The Glow Discharge Spectrometer(GDS) was used for quantitative analysis of results. The results of using GDS, the Inconel 600 corrodes more than Inconel 690 at pH 7 and pH 9. However, it is observed that Inconel 690 corrodes more than Inconel 600 at pH 4. Those results is estimated that test sections had the effect of transient. The long terms of experiment is required to minimize and solve the problem.

• Journal of Sensor Science and Technology
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• v.26 no.1
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• pp.7-14
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• 2017

A threshold-based fall recognition algorithm using a tri-axial accelerometer and a bi-axial gyroscope mounted on the skin above the upper sternum was proposed to recognize fall-like activities of daily living (ADL) events. The output signals from the tri-axial accelerometer and bi-axial gyroscope were obtained during eight falls and eleven ADL action sequences. The thresholds of signal vector magnitude (SVM_Acc), angular velocity (${\omega}_{res}$), and angular variation (${\theta}_{res}$) were calculated using MATLAB. When the measured values of SVM_Acc, ${\omega}_{res}$, and ${\theta}_{res}$ were compared to the threshold values (TH1, TH2, and TH3), fall-like ADL events could be distinguished from a fall. When SVM_Acc was larger than 2.5 g (TH1), ${\omega}_{res}$ was larger than 1.75 rad/s (TH2), and ${\theta}_{res}$ was larger than 0.385 rad (TH3), eight falls and eleven ADL action sequences were recognized as falls. When at least one of these three conditions was not satisfied, the action sequences were recognized as ADL. Fall-like ADL events such as jogging and jumping up (or down) have posed a problem in distinguishing ADL events from an actual fall. When the measured values of SVM_Acc, ${\omega}_{res}$, and ${\theta}_{res}$ were applied to the sequential processing algorithm proposed in this study, the sensitivity was determined to be 100% for the eight fall action sequences and the specificity was determined to be 100% for the eleven ADL action sequences.