• Progress in Medical Physics
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• v.30 no.4
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• pp.120-127
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• 2019

Purpose: This study was designed to evaluate the dosimetric performance of Mobius3D by comparison with an aSi-based electronic portal imaging device (EPID) and Octavius 4D, which are conventionally used for patient-specific prescription dose verification. Methods: The study was conducted using nine patients who were treated by volumetric modulated arc therapy. To evaluate the feasibility of Mobius3D for prescription dose verification, we compared the QA results of Mobius3D to an aSi-based EPID and the Octavius 4D dose verification methods. The first was the comparison of the Mobius3D verification phantom dose, and the second was to gamma index analysis. Results: The percentage differences between the calculated point dose and measurements from a PTW31010 ion chamber were 1.6%±1.3%, 2.0%±0.8%, and 1.2%±1.2%, using collapsed cone convolution, an analytical anisotropic algorithm, and the AcurosXB algorithm respectively. The average difference was found to be 1.6%±0.3%. Additionally, in the case of using the PTW31014 ion chamber, the corresponding results were 2.0%±1.4%, 2.4%±2.1%, and 1.6%±2.5%, showing an average agreement within 2.0%±0.3%. Considering all the criteria, the Mobius3D result showed that the percentage dose difference from the EPID was within 0.46%±0.34% on average, and the percentage dose difference from Octavius 4D was within 3.14%±2.85% on average. Conclusions: We conclude that Mobius3D can be used interchangeably with phantom-based dosimetry systems, which are commonly used as patient-specific prescription dose verification tools, especially under the conditions of 3%/3 mm and 95% pass rate.

• Journal of radiological science and technology
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• v.45 no.6
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• pp.553-560
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• 2022

The purpose of this study is to evaluate the clinical risk according to the applicator heterogeneity, mislocation, and tissue heterogeneity correction through a dose verification program during brachytherapy of cervical cancer. We performed image processing with MATLAB on images acquired with CT simulator. The source was modeled and stochiometric calibration and Monte-Carlo algorithm were applied based on dwell time and location to calculate the dose, and the secondary cancer risk was evaluated in the dose verification program. The result calculated by correcting for applicator and tissue heterogeneity showed a maximum dose of about 25% higher. In the bladder, the difference in excess absolute risk according to the heterogeneity correction was not significant. In the rectum, the difference in excess absolute risk was lower than that calculated by correcting applicator and tissue heterogeneity compared to the water-based calculation. In the femur, the water-based calculation result was the lowest, and the result calculated by correcting the applicator and tissue heterogeneity was 10% higher. A maximum of 14% dose difference occurred when the applicator mislocation was 20 mm in the Z-axis. In a future study, it is expected that a system that can independently verify the treatment plan can be developed by automating the interface between the treatment planning system and the dose verification program.

• Journal of radiological science and technology
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• v.46 no.6
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• pp.527-533
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• 2023

The purpose of this study is to evaluate the clinical risk of spinal radiosurgery by calculating the dose difference due to dose calculation algorithm and multi-leaf collimator positioning error. The images acquired by the CT simulator were recalculated by correcting the multi-leaf collimator position in the dose verification program created using MATLAB and applying stoichiometric calibration and Monte Carlo algorithm. With multi-leaf collimator positioning error, the clinical target volume (CTV) showed a dose difference of up to 13% in the dose delivered to the 95% volume, while the gross tumor volume (GTV) showed a dose difference of 9%. The average dose delivered to the total volume showed dose variation from -8.9% to 9% and -10.1% to 10.2% for GTV and CTV, respectively. The maximum dose delivered to the total volume of the spinal cord showed a dose difference from -14.2% to 19.6%, and the dose delivered to the 0.35 ㎤ volume showed a dose difference from -15.5% to 19.4%. In future research, automating the linkage between treatment planning systems and dose verification programs would be useful for spinal radiosurgery.

• Nuclear Engineering and Technology
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• v.56 no.4
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• pp.1330-1338
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• 2024

Information on isotopic composition and geometric structure is necessary for identifying a true warhead. Nevertheless, such classified information should be protected physically or electronically. With a novel Hash encryption algorithm, this paper presents a Monte Carlo-based design of a neutron activation analysis verification module. The verification module employs a thermal neutron source, a non-uniform mask (physically encrypting information about isotopic composition and geometric structure), a gamma detector array, and a Hash encryption algorithm (for electronic encryption). In the physical field, a non-uniform mask is designed to distort the characteristic gamma rays emitted by the inspected item. Furthermore, as part of the Hash algorithm, a key is introduced to encrypt the data and improve the system resolution through electronic design. In order to quantify the difference between items, Hamming distance is used, which allows data encryption and analysis simultaneously. Simulated inspections of simple objects are used to quantify system performance. It is demonstrated that the method retains superior resolution even with 1% noise level. And the performances of anti-statistical attack and anti-brute force cracking are evaluated and found to be very excellent. The verification method lays a solid foundation for nuclear disarmament verification in the upcoming era.

• Atmosphere
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• v.27 no.2
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• pp.235-249
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• 2017

This paper describes methodology verifying near-surface predictability of numerical weather prediction models against the surface synoptic weather station network (SYNOP) observation. As verification variables, temperature, wind, humidity-related variables, total cloud cover, and surface pressure are included in this tool. Quality controlled SYNOP observation through the pre-processing for data assimilation is used. To consider the difference of topographic height between observation and model grid points, vertical inter/extrapolation is applied for temperature, humidity, and surface pressure verification. This verification algorithm is applied for verifying medium-range forecasts by a global forecasting model developed by Korea Institute of Atmospheric Prediction Systems to measure the near-surface predictability of the model and to evaluate the capability of the developed verification tool. It is found that the verification of near-surface prediction against SYNOP observation shows consistency with verification of upper atmosphere against global radiosonde observation, suggesting reliability of those data and demonstrating importance of verification against in-situ measurement as well. Although verifying modeled total cloud cover with observation might have limitation due to the different definition between the model and observation, it is also capable to diagnose the relative bias of model predictability such as a regional reliability and diurnal evolution of the bias.

• Journal of Korean Home Economics Education Association
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• v.8 no.1
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• pp.51-57
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• 1996

The purpose of this study were to examine the difference of the effect of CAI and students’attitude to Home Economics Class through CAI. 120 girl students of the first year were chosen at B middle school in Daegu. Among them each 30 students were classified into 4 groups； High Intelligence group/Individual learning pattern, High Intelligence group/Small group learning pattern, Low Intelligence group/Individual learning pattern, Low Intelligence group/Small group learning pattern. The task of learning was “management of washing”Unit of the second grade. The data were processed with Cronbach’s ${\alpha}$, t-test, ANOVA by SPSS/PC(sup)+. The research findings are as follows： 1. In the verification of CAI Learning effect according to student group pattern, there is no difference between Individual learning pattern and Small group learning pattern in Achivement and Retention of learning. 2. In the verification of CAI Learning effect according to student intelligence level, there is no difference between High Intelligence group and Low Intelligence group in Achivement and Retention of learning. 3. The result of students’attitude to Home Economics Class verificated is an follows. (1) Individual learning pattern is more attensive than Small group learning pattern, but there is no difference in Intelligence level. (2) Low Intelligence group is more positive than High Intelligence group, and Small group learning pattern is more positive than Individual learning pattern in a view of Home Economics Class after using CAI.

• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.745-750
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• 2009

In Korea, since the implementation of the GMO Law, the intrest of biosafety level 3(BL3) lab. is increasing. In this study, using CONTAM which is applying multizone modelling, the multizone simulation for design verification of BL3 lab. was performed. In BL3 lab., because required air change rate is greater than general estimated air-conditioning load and it is difficult to maintain room pressure difference efficiently, to maintain pressure difference between laboratory rooms is important through sealing condition of doors and proper airflow control of laboratory rooms. In this study, about BL3 lab.(M. tuberculosis research lab.), the multizone simulation for four kind of biohazard scenarios was performed in the case of unexpected spread of contaminants in the laboratory room, anteroom, corridor and inside of BSC. Multizone simulation results show that these approach methods are used as a tool for the design and verification of BL3 lab.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.21 no.12
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• pp.671-677
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• 2009

In Korea, since the implementation of the LMO Law, the interest of biosafety level 3(BL3) lab. is increasing. In this study, using CONTAM which is applying multizone modelling, the multizone simulation for design verification of BL3 lab. is performed. In BL3 lab., because required air change rate is greater than general estimated air-conditioning load and it is difficult to maintain room pressure difference efficiently, to maintain pressure difference between laboratory rooms is important through sealing condition of doors and proper airflow control of laboratory rooms. In this study, about BL3 lab,(M. tuberculosis research lab.), the multizone simulation for four kind of biohazard scenarios is carried out in the case of unexpected spread of contaminants in the laboratory room, anteroom, corridor and inside of BSC. Multizone simulation results show that these approach methods are used as a tool for the design and verification of BL3 lab.

• Journal of Korea Water Resources Association
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• v.37 no.2
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• pp.155-161
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• 2004

The purpose of this study is to verify LSPIV technique. Verification was made using moving cart with known velocity. The difference of velocity values obtained using these methods are within 5％, which means that LSPIV can be used in the field with reasonable accuracy After verification, LSPIV was applied to the river. The Neungwon stream and the Gonjiam stream, tributaries of the Kyungan stream, were selected as the test sites for application. The results of the test application were compared with those obtained by 3-D electromagnetic current meter and electron-wave surface velocity meter. Results show that the velocity values obtained using LSPIV coincide well with those obtained using conventional devices with maximum difference of 8％.

• Journal of Korea Multimedia Society
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• v.24 no.8
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• pp.1171-1177
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• 2021

Measuring and evaluation of audience's visual message perception are crucial process for scientific production of visual content. This study tried to evaluate the difference of viewer's awareness of visual object depends on his or her inherent characteristics like conservatism using an eye tracker system. Especially, this experiment tested research questions about positive correlation between conservatism and peoples' eye movements following the sound visual messages. 57 subjects participated in the test. Two different groups were exposed to two visual elements representing 'the conservative' and 'the liberal'. The results showed that people tended to have different way of seeing visual objects according to their inherent characteristics. Also by comparing the gaze time at the object and area of interest(AOI) in visual, this study is able to verify the existence of 'positive way of seeing' and 'negative way of seeing'. The two different ways of seeing have their own trail of eye movement.