• Journal of the Korean Society of Radiology
• /
• v.16 no.7
• /
• pp.863-870
• /
• 2022

DLG (Dosimetric Leaf Gap) and transmission factor are important parameters of MLC modeling in treatment planning system. In this study, DLG and transmission factor of HD-MLC were measured using detector with different measuring volumes, and the accuracy of the treatment plans was evaluated according to the DLG values. DLG was measured using the dynamic sweeping gap method with Semiflux3D and MicroDiamond detectors. Then, 10 radiation treatment plans were generated to optimize the DLG value and compared with the measurement results. Photon energies 6, 8, 10 MV, the DLG measured by Semiflux3D were 0.76, 0.83, and 0.85 mm, and DLG measured by MicroDiamond were 0.78, 0.86, and 0.9 mm. All plans were measured by portal dosimetry and analyzed using Gamma Evaluation. In the 6 MV photon beams, the average gamma passing rate were 94.3% and 98.4% for DLG 0.78 mm and 1.15 mm. In the 10 MV photon beam, the average gamma passing rate were 91.2% and 97.6% for DLG 0.9 mm and 1.25 mm. HD-MLC needs accurate modeling in the treatment planning system. DLG could be used measured data using small volume detector. However, for better radiation therapy, DLG should be optimized at the commissioning stage of LINAC.

• Journal of Korea Water Resources Association
• /
• v.47 no.4
• /
• pp.343-356
• /
• 2014

The SWMM (storm water management model) has been widely used in the world and is a watershed runoff simulation model used for a single event or a continuous simulation of runoff quantity and quality. However, there are many uncertain parameters in the watershed runoff continuous simulation module and the water quality module, which make it difficult to use the SWMM. The purpose of the study is to develop an automatic calibration module of the SWMM not only for watershed runoff continuous simulation, but also water quality simulation. The automatic calibration module was developed by linking the SWMM with the SCE-UA (shuffled complex evolution-University of Arizona) that is a global optimization algorithm. Estimation parameters of the SWMM were selected and search ranges of them were reasonably configured. The module was validated by calibration and verification of the watershed runoff continuous simulation model and the water quality model for the Donghyang Stage Station Basin. The calibration results for watershed runoff continuous simulation model were excellent and those for water quality simulation model were generally satisfactory. The module could be used in various studies and designs for watershed runoff and water quality analyses.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.14 no.2
• /
• pp.96-108
• /
• 2011

Going abreast of high public concerns on the environment, the need of environmental modeling has been increased to assess the impact of space exploitation of environment. GIS offers potential solutions to the many problems encountered during water-quality modeling. But there are also many problems associated with the modeling. The preparation of necessary parameters for the modeling can be complicated. Also, the results from one model can be different from each other even the same area is analyzed. This paper aims to develop the data processing system to couple the Qual2E and HyGIS in which Qual2E input and output data files can be created, modified and processed using HyGIS and assess the performance of the system. A structural analysis and standardization of modeling are conducted to identify data flow and processing of Qual2E. Algorithms of the defined processors are designed and developed as component modules. The data model of HyGIS-Qual2E is designed, and GUI(Graphical User Interface) is developed using Visual Basic 6.0 and GDK.

• Journal of Korea Water Resources Association
• /
• v.54 no.2
• /
• pp.105-119
• /
• 2021

An increase in the frequency and intensity of both floods and droughts has been recently observed due to an increase in climate variability. Especially, land-use change associated with industrial structure and urbanization has led to an imbalance between water supply and demand, acting as a constraint in water resource management. Accurate rainfall-runoff analysis plays a critical role in evaluating water availability in the water budget analysis. This study aimed to explore various continuous rainfall-runoff models over the Soyanggang dam watershed. Moreover, the ensemble modeling framework combining multiple models was introduced to present scenarios on streamflow considering uncertainties. In the ensemble modeling framework, rainfall-runoff models with fewer parameters are generally preferred for effective regionalization. In this study, more than 40 continuous rainfall-runoff models were applied to the Soyanggang dam watershed, and nine rainfall-runoff models were primarily selected using different goodness-of-fit measures. This study confirmed that the ensemble model showed better performance than the individual model over different flow regimes.

• Journal of the Korean Society of Radiology
• /
• v.17 no.1
• /
• pp.1-9
• /
• 2023

For optimal image quality of computer tomography angiography (CTA), different iodine concentrations and scan parameters were applied to quantitatively evaluate the image quality characteristics of filtered back projection (FBP), hybrid-iterative reconstruction (hybrid-IR), and deep learning reconstruction (DLR). A 320-row-detector CT scanner scanned a phantom with various iodine concentrations (1.2, 2.9, 4.9, 6.9, 10.4, 14.3, 18.4, and 25.9 mg/mL) located at the edge of a cylindrical water phantom with a diameter of 19 cm. Data obtained using each reconstruction technique was analyzed through noise, coefficient of variation (COV), and root mean square error (RMSE). As the iodine concentration increased, the CT number value increased, but the noise change did not show any special characteristics. COV decreased with increasing iodine concentration for FBP, adaptive iterative dose reduction (AIDR) 3D, and advanced intelligent clear-IQ engine (AiCE) at various tube voltages and tube currents. In addition, when the iodine concentration was low, there was a slight difference in COV between the reconstitution techniques, but there was little difference as the iodine concentration increased. AiCE showed the characteristic that RMSE decreased as the iodine concentration increased but rather increased after a specific concentration (4.9 mg/mL). Therefore, the user will have to consider the characteristics of scan parameters such as tube current and tube voltage as well as iodine concentration according to the reconstruction technique for optimal CTA image acquisition.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.21 no.2
• /
• pp.8-18
• /
• 2020

An Exponential Bandwidth Harmony Search with Centralized Global Search (EBHS-CGS) was developed to enhance the performance of a Harmony Search (HS). EBHS-CGS added two methods to improve the performance of HS. The first method is an improvement of bandwidth (bw) that enhances the local search. This method replaces the existing bw with an exponential bw and reduces the bw value as the iteration proceeds. This form of bw allows for an accurate local search, which enables the algorithm to obtain more accurate values. The second method is to reduce the search range for an efficient global search. This method reduces the search space by considering the best decision variable in Harmony Memory (HM). This process is carried out separately from the global search of the HS by the new parameter, Centralized Global Search Rate (CGSR). The reduced search space enables an effective global search, which improves the performance of the algorithm. The proposed algorithm was applied to a representative optimization problem (math and engineering), and the results of the application were compared with the HS and better Improved Harmony Search (IHS).

• Journal of the Institute of Electronics and Information Engineers
• /
• v.49 no.10
• /
• pp.181-186
• /
• 2012

In this paper, we describe the synthesis of robust and non-fragile Kalman filter design for a class of uncertain linear system with polytopic uncertainties and filter gain variations. The sufficient condition of filter existence, the design method of robust non-fragile filter, and the measure of non-fragility in filter are presented via LMIs(Linear Matrix Inequality) technique. And the obtained sufficient condition can be represented as PLMIs(parameterized linear matrix inequalities) that is, coefficients of LMIs are functions of a parameter confined to a compact set. Since PLMIs generate infinite LMIs, we use relaxation technique, find the finite solution for robust non-fragile filter, and show that the resulting filter guarantees the asymptotic stability with parameter uncertainties and filter fragility. Finally, a numerical example will be shown.

• Journal of radiological science and technology
• /
• v.33 no.4
• /
• pp.355-362
• /
• 2010

This study determines a range of CT parameter values in Brain CT which are minimizing patient absorption dose without compromising the image quality and optimal exposure condition. We measured dose and image noise using conventional CT parameters in Brain CT. In additon, we evaluated dose, SNR and PSNR of head phantom images while changing kVp and rotation time. In this study, effectiveness of dose that was achieved from dose reproducible experiments in conventional head CT condition is determined by changing kVp and rotation time. Dose and PSNR is related to low dose-high resolution condition. In conclusion, we suggest that using proposed conditions is effective for imaging to compare with conditions proposed by the manufacturer.

• Journal of the Korea Society of Computer and Information
• /
• v.28 no.10
• /
• pp.277-289
• /
• 2023

The purpose of this study is to explore the mechanisms influencing consumers' continued intention to use live-streaming e-commerce for shopping, providing strategic recommendations for businesses to optimize live-streaming activities and enhance consumers' shopping experiences. In this paper, we innovatively integrate the UTAUT2 and ECM theoretical models to construct a comprehensive research framework. This framework not only thoroughly reveals the multi-dimensional variables that affect consumers' continuous usage intentions but also delves deeply into the interrelationships among these variables. We collected data extensively through surveys and utilized the Structural Equation Modeling and Bootstrapping methods for analysis. The research results indicate that performance expectation plays a crucial role in determining the continuous usage intention; satisfaction exerts a significant mediating effect between performance expectation and four other variables concerning continuous usage intention; and expectation confirmation stands out as the most prominent factor in enhancing satisfaction.

• Journal of the Korean Institute of Gas
• /
• v.20 no.5
• /
• pp.104-111
• /
• 2016

Recently, the quantities of chemical material are increasing in chemical industries. At that time, release accident is increasing due to aging of equipment, mechanical failure, human error, etc. and industrial complexes found community properties in a specific area. For that matter, chemical release accident can lead to hight probability of large disaster. There is a need to analyze the boundaries optimal sensor placement calculated by selecting release scenarios through release condition and wether condition in a chemical process for release detection and response. This paper is to investigate chlorine release accident scenarios using COMSOL. Through accident scenarios, a numerical calculation is studied to determine optimized sensor placement with weight of detection probability, detection time and concentration. In addition, validity of sensor placement is improved by robustness analysis about unpredicted accident scenarios. Therefore, this verifies our studies can be effectively applicable on any process. As mention above, the result of this study can help to place mobile sensor, to track gas release based concentration data.