• Nuclear Engineering and Technology
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• v.53 no.1
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• pp.266-272
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• 2021

In the pulsed electron beam generators, such as plasma focus devices and linear induction accelerators whose electron pulse width is in the range of nanosecond and less, as well as in cases where there is no direct access to electron beam, like runaway electrons in Tokamaks, measurement of the electron energy spectrum is a technical challenge. In such cases, the indirect measurement of the electron spectrum by using the bremsstrahlung radiation spectrum associated with it, is an appropriate solution. The problem with this method is that the matrix equation between the two spectrums is an ill-conditioned equation, which results in errors of the measured X-ray spectrum to be propagated with a large coefficient in the estimated electron spectrum. In this study, a method based on the neural network and the MCNP code is presented and evaluated to recover the electron spectrum from the X-ray generated by collision of the electron beam with a target. Multilayer perceptron network showed good accuracy in electron spectrum recovery, so that for the X-ray spectrum with errors of 3% and 10%, the network estimated the electron spectrum with an average standard error of 8% and 11%, on all of the energy intervals.

• Journal of the Korea Society of Computer and Information
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• v.27 no.8
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• pp.169-176
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• 2022

With the continuous development of technologies related to 5G, artificial intelligence, and autonomous vehicle systems, standards and services for V2X and C-ITS environments are being studied a lot. BSM (basic safety message) was adopted as a standard for exchanging data between vehicles based on data collected and generated by vehicle systems in a V2V environment. In this paper, we propose a framework that can safely store BSM messages and effectively check the stored messages using Event-Sourcing and CQRS patterns. The proposed framework can securely store and manage BSM messages using hash functions. And it has the advantage of being able to check the stored BSM data in real time based on the time series and to reproduce the state.

• Journal of information and communication convergence engineering
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• v.22 no.2
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• pp.165-171
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• 2024

In this study, we present a novel approach for enhancing chest X-ray image classification (normal, Covid-19, edema, mass nodules, and pneumothorax) by combining contrastive learning and machine learning algorithms. A vast amount of unlabeled data was leveraged to learn representations so that data efficiency is improved as a means of addressing the limited availability of labeled data in X-ray images. Our approach involves training classification algorithms using the extracted features from a linear fine-tuned Momentum Contrast (MoCo) model. The MoCo architecture with a Resnet34, Resnet50, or Resnet101 backbone is trained to learn features from unlabeled data. Instead of only fine-tuning the linear classifier layer on the MoCopretrained model, we propose training nonlinear classifiers as substitutes for softmax in deep networks. The empirical results show that while the linear fine-tuned ImageNet-pretrained models achieved the highest accuracy of only 82.9% and the linear fine-tuned MoCo-pretrained models an increased highest accuracy of 84.8%, our proposed method offered a significant improvement and achieved the highest accuracy of 87.9%.

• Journal of Electrochemical Science and Technology
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• v.15 no.2
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• pp.268-275
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• 2024

The study examined the electrogeneration of hypochlorite ions (ClO^-) via electrolysis of aqueous NaCl solutions using a dimensionally stable anode-type (DSA-type) electrode based on platinum and palladium oxides supported on titanium mesh (Ti/PtPd(10%)O_x). The electrogenerated ClO^- was quantified on the basis of the absorption band at 292 nm (A_λ = 292) of the UV-Vis spectrum. The effect of initial pH, concentration of NaCl, cell potential difference and electrolysis time were investigated in this study. The results showed that the electrolysis of aqueous NaCl solutions increases the solution pH up to high values (≥ 8.0) that favor the formation of ClO^- over chlorine or hypochlorous acid. The hypochlorite concentration increases significantly at pH values > 7.0 and shows a linear trend with increasing NaCl concentration and with increasing cell potential difference. When the cell potential and NaCl concentration are held constant, the maximum hypochlorite value during electrolysis depends on both the cell potential and NaCl concentration. The Ti/PtPd(10%)O_x anode favors the production of hypochlorite ions, making this anode a promising material for use in electrochemical oxidation of wastewater via an indirect mechanism.

• Progress in Superconductivity and Cryogenics
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• v.26 no.2
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• pp.5-8
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• 2024

Recently, Lee et al. claimed that LK-99 isthe first room-temperature superconductor at ambient pressure, which quickly captured the attention of both the scientific community and the general public. We tried to replicate Pb_10-xCu_x(PO₄)₆O, called as LK-99, and characterized its physical properties by measuring the electrical resistance and Meissner effect. The electrical resistance results for different batches exhibited structural phase transitions at different temperatures, and the magnetic measurements indicated weak diamagnetism at 300 K, which is weaker than that of water. Taken together with the structural analysis, these results suggest that the resistivity transitions are incurred by Cu-S compound generated as a byproduct during the synthesis of LK-99 and LK-99 is not a room-temperature superconductor.

• Journal of Radiation Industry
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• v.17 no.4
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• pp.533-542
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• 2023

We developed an emergency national manual for preservation of cultural heritage using irradiation disinfection technic under flood disaster. And we examined its practicality with a critical radiation dose on fungi that occur at water-logged event in order to prevent fungal damage that occurs during submersion. The X-ray irradiation for this experiment was conducted at the Production Technology Research Institute located in Yeongcheon, Gyeongsangbuk-do. A disinfection critical dose of 12 kGy was selected for two types of fungi known to spread rapidly and are resistant to radiation to submerged cultural properties, and this experiments were conducted by setting a target dose of 12kGy at 8.37mA at 5MeV. Under the above conditions, only continuity of irradiated samples were completely disinfected. This suggests that continuity of irradiation is important for fungal disinfection.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.18 no.8
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• pp.2298-2315
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• 2024

This paper introduces a method aimed at diagnosing the presence or absence of lesions by detecting anomalies in Chest X-ray images. The proposed approach is based on the PatchCore anomaly detection method, which extracts a feature vector containing location information of an image patch from normal image data and calculates the anomaly distance from the normal vector. However, applying PatchCore directly to medical image processing presents challenges due to the possibility of diseases occurring only in specific organs and the presence of image noise unrelated to lesions. In this study, we present an image alignment method that utilizes affine transformation parameter prediction to standardize already captured X-ray images into a specific composition. Additionally, we introduce a region-specific abnormality detection method that requires affine-transformed chest X-ray images. Furthermore, we propose a method to enhance application efficiency and performance through feature map hard masking. The experimental results demonstrate that our proposed approach achieved a maximum AUROC (Area Under the Receiver Operating Characteristic) of 0.774. Compared to a previous study conducted on the same dataset, our method shows a 6.9% higher performance and improved accuracy.

• Radiation Oncology Journal
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• v.18 no.2
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• pp.133-137
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• 2000

Purpose :To investigate whether combined beta-carotene with X-Irradiation has more enhanced radition response than X-irradiation or not, we peformed a experiment about in vitro cytotoxlcity of beta-carotene and/or X-irradiation in the fibrosarcoma cells, tumor growth delay of combined beta-caroten with/or X-irradiation in the mouse fibrosarcoma. Materials and Methods : 2$\%$ emulsion of beta-carotene was serially diluted and used. X-Irradiation was given by 6 MeV linear accelerator. The cytotoxicity of beta-carotene in vitro was evaluated from clonogenic assay. To compare the cytotoxiclty between combined beta-carotene with X-irradiation and X-irradiation group, 2 mg/ml of beta-carotene was contacted to fibrosarcoma (FSall) cells for 1 hour before X-irradiation. For the tumor growth delay, single 20 Gy was given to FSall tumor hearing C3H/N mice whic was classified as beta-crotene with X-irradiation group (n=5) and X-irradiation alone group (n=5). 0.2 ml of 20 mg/kg of beta-carotene were i.p. injected to mice 30 minute before X-irradiation in the beta-crotene with X-irradiation group. The tumor growth delay defined as the time which reach to 1,000 mm$^{3}$ of tumor volume. Results : (1) Cytotoxicity in vitro: 1) survival fraction at beta-carotene concentration of 0.002,0.02,0.2 and 2 mg/ml were 0.69$\pm$0.07, 0.59$\pm$0.08, 0.08$\pm$0.008 and 0.02$\pm$0.006, respectively. 2) each survival fraction at 2, 4, 6 and 8 Gy in the 2 mg/ml of beta-carotene + X-irradiation group were 0.13$\pm$0.05, 0.03$\pm$0.005, 0.01 $\pm$0.002 and 0.009$\pm$0.0008, respectively. But each survival fraction at same irradiation dose in the X-irradiation group were 0.66$\pm$0.05, 0.40$\pm$0.04, 0.11$\pm$0.01 and 0.03$\pm$0.006, respectively(p<0.05). (2) The time which reach to 1,000 mm$^{3}$ of tumor volume of beta-carotene + X-irradiation group and X-irradiation alone group were 18, 19 days, respectively(p>0.05) Conclusion : The contact of beta-caroten to Fsall cells showed mild cytotoxicity which 띤as increased according to concentration. The cytotoxicity of combined beta-carotene with X-irradiation more increased than that of X-irradiation, additionally, And there was significant difference of cytotoxicity between two groups. But there were no significant difference of the growth delay of fibrosarcoma between two groups.

• Food Science and Preservation
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• v.24 no.7
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• pp.957-964
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• 2017

The purpose of this study was to determine the optimum spray drying conditions of soft persimmon latte using response surface methodology that is a statistical procedure used for optimization studies. A central composite design was applied to investigate the effects of independent variables, inlet temperature ($X_1$), air flow rate ($X_2$), and feed flow rate ($X_3$), on responses such as yield, water absorption index, and total phenolic compounds. Statistical analysis revealed that independent variables significantly affected all the responses. A maximum yield of 8.11 g was obtained at $90^{\circ}C$ of $X_1$, 51.82 mL/min of $X_2$ and 7.00 mL/min of $X_3$. A minimum water absorption index of 0.58 was obtained at $101^{\circ}C$ of $X_1$, 60.00 mL/min of $X_2$ and 17.00 mL/min of $X_3$. A maximum total phenolic compounds of $298.02{\mu}g/mL$ was obtained at $90^{\circ}C$ of $X_1$, 43.33 mL/min of $X_2$ and 17.00 mL/min of $X_3$. In conclusion, the best spray drying conditions were as follows: $X_1$, $90^{\circ}C$; $X_2$, 53 mL/min; $X_3$, 17 mL/min. Under those optimal conditions, the powder's yield (7.46 g), water absorption index (0.54), and the content of total phenolic compounds ($294.75{\mu}g/mL$) were estimated.

• The Korean Nurse
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• v.30 no.3
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• pp.49-65
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• 1991

This study was carried out to assess the problems with the pregnant women, and check out the risk-factors in the high-risk pregnancies, using a simplified antepartum risk-scoring system, which was revised from Edwards' scoring system to be suitable for Korean situaition. This instrument was included 4 categories, demographic, obstetric, medical and miscellaneous factors. This survey was based on the 1300 pregnant women who were admitted, $x^2$-test, F-test, Pearsons correation, using statistical package SAS in NAS computer system, KIST. The results of the study were as follows; 1. 1313 infants were deliveried of these 560 infants(42.7%) were born to mothers with risk-scores > 7, and 753 infants(57.3%) were born to mothers risk-scores <7. 2. Maternal age" parity, education level, of the demographic factors were significant relation statistically to identify the high risk pregnancies($X^2$=20.88, 42.87, 15.60 P < 0.01). 3. C-section, post term, incompetent cervix, uterine anomaly, polyhydramnios, congenital anomaly, sensitized RH negative, abortion, preeclampsia, excessive size infant, premature, low birth weight infanl, abnormal presentation, perinatal loss, multiple pregnancy, of the obstetric factors were significant relation statistically to identify the high risk-pregnancies. ($X^2$ = 175.96, 87.5, 16.28, 21.78, 9.46, 8. 10, 6.75, 22.9, 64.84, 6.93, 361.43, 185.55, 78.65, 45.52, P < 0.01). 4. Abnormal nutrition, anemia, UTI, other medicalcondition(pulmonary disease, severe influenza), heart disease, V.D., of the miscellaneous and medical factors, were significant relation statistically to identify the high risk-pregnancies. 5. Premature, low birth weight infant, contracted pelvis, abnormal presentation, of the risk factors were significantly related with Apgar score at 1 '||'&'||' 5 minute after birth and neonatal body weight. 6. Apgar score at 1 '||'&'||' 5 minute after, birth and neonatal body weight were significantly negative correlated with risk-score. 7. There were statistically significant difference between risk-score and Apgar score at 1 '||'&'||' 5 minute after birth, 3 group(0-3, 4-6, above 7), and neonatal body weight, 2 group(below 2.5kg, the other group) (F=104.65, 96.61, 284.92, P<0.01). 8. Apgar score at 1 '||'&'||' 5 minute after birth(below 7), and neonatal body weight(below 2.5kg), were significant relation statistically with risk score.($x^2$=65.99, 60.88, 177.07, P<0.01) were 60.8 %, 60% . 9. Correct classifications of morbid infants(l '||'&'||' 5 minute Apgar score < 7) were 77.8%, 83.8% and that of nonmorbid infants(l '||'&'||' 5 minute Apgar score > 7) were 60.8%, 60%. 10. There were statistically significant difference between dislribution of maternal risk-score among the morbid infants(l '||'&'||' 5 minute Apgar score < 7) and non morbid infants(l '||'&'||' 5 minute Apgar score> 7) ($x^2$=64.8, 58.8, P < 0.001). 11. There were statistically significant difference between distribution of morbid infants(l '||'&'||' 5 minute Apgar score < 7) and fetal death. 12. The predictivity for classifying high.risk cases was 12 % and for classifying low-risk cases was 98.3 % in 5 minute Apgar score. Suggestions for further studies are as follows; 1. Contineous prospective studies, using this newly revised scoring system are strongly recommended in the stetric service. 2. Besides risk facto~s used in this study, assessmenl of risks by factors in another scoring system and paralled studies related to perinatal outcome are strongly recommended.