• Nuclear Engineering and Technology
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• v.55 no.6
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• pp.2018-2025
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• 2023

In our previous study, we proposed an integrated PG-PET-based imaging method to increase the prediction accuracy for patient dose distributions. The purpose of the present study is to experimentally validate the feasibility of the PG-PET system. Based on the detector geometry optimized in the previous study, we constructed a dual-head PG-PET system consisting of a 16 × 16 GAGG scintillator and KETEK SiPM arrays, BaSO₄ reflectors, and an 8 × 8 parallel-hole tungsten collimator. The performance of this system as equipped with a proof of principle, we measured the PG and positron emission (PE) distributions from a 3 × 6 × 10 cm³ PMMA phantom for a 45 MeV proton beam. The measured depth was about 17 mm and the expected depth was 16 mm in the computation simulation under the same conditions as the measurements. In the comparison result, we can find a 1 mm difference between computation simulation and measurement. In this study, our results show the feasibility of the PG-PET system for in-vivo range verification. However, further study should be followed with the consideration of the typical measurement conditions in the clinic application.

• Nuclear Engineering and Technology
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• v.53 no.3
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• pp.942-948
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• 2021

The aim of this work is to help inform the decision for choosing a convenient material for the PGAA (Prompt Gamma Activation Analysis) collimator plug to be installed at the tangential channel of the Moroccan Triga Mark II Research Reactor. Two families of materials are usually used for collimator construction: a mixture of high-density polyethylene (HDPE) with boron, which is commonly used to moderate and absorb neutrons, and heavy materials, either for gamma absorption or for fast neutron absorption. An investigation of two different collimator designs was performed using N-Particle Monte Carlo MCNP6.2 code with the ENDF/B-VII.1 and MCLIP84 libraries. For each design, carbon steel and lead materials were used separately as collimator heavy materials. The performed study focused on both the impact on neutron beam quality and the neutron-gamma background at the exit of the collimator beam tube. An analysis and assessment of the principal findings is presented in this paper, as well as recommendations.

• Nuclear Engineering and Technology
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• v.55 no.3
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• pp.1031-1035
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• 2023

Neutron is an indirectly ionizing particle without charge, which is normally measured by detecting reaction products. Neutron detection system based on measuring gadolinium-converted gamma-rays is a good way to monitor the neutron because the representative prompt gamma-rays of gadolinium have low energies (79, 89, 182, and 199 keV). Low energy gamma-rays and their high attenuation coefficient on materials allow the simple design of a detector easier to manufacture. Thus, we designed a cadmium zinc telluride detector to investigate feasibility of simultaneous detection of gamma-rays and neutrons by using the Monte-Carlo simulation, which was divided into two parts; first was gamma-detection part and second was gamma- and neutron-simultaneous detection part. Consequently, we confirmed that simultaneous detection of gamma-rays and neutrons could be feasible and valid, although further research is needed for adoption on real detection.

• Journal of the Korean Association of Geographic Information Studies
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• v.19 no.1
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• pp.167-179
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• 2016

The safety of SOC facilities is constantly under threat by the globally increasing abnormal climate. Responding to disasters requires prompt decision-making such as suggesting evacuation paths. For doing so, spatio-temporal information with convergence of disaster information and SOC facility information must be utilized. Such information is being collected separately by the government or related organizations, but not collectively. The collective control of the separately collected disaster information and the generation of SOC facility safety and damage information are required for prompt disaster response. Also, as disaster information requires spatio-temporal convergence in its nature, the construction of an inventory that integrates related information and assists disaster response decision-making is required. A plan to construct a facility importance, risk, and damage estimation inventory for assisting prompt disaster response decision-making is suggested in this study. Through this study, the disaster and SOC facility-related data, which are being managed separately, can be collected and standardized. The integrated information required for the estimation of facility importance, risk, and damage can be provided. The suggested system is expected to be used as a decision-making tool for proactive disaster response.

• KIPS Transactions on Software and Data Engineering
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• v.12 no.11
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• pp.481-492
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• 2023

This study explores how to build a Korean dataset to extract information from text using generative large language models. In modern society, mixed information circulates rapidly, and effectively categorizing and extracting it is crucial to the decision-making process. However, there is still a lack of Korean datasets for training. To overcome this, this study attempts to extract information using text-based zero-shot learning using a generative large language model to build a purposeful Korean dataset. In this study, the language model is instructed to output the desired result through prompt engineering in the form of "system"-"instruction"-"source input"-"output format", and the dataset is built by utilizing the in-context learning characteristics of the language model through input sentences. We validate our approach by comparing the generated dataset with the existing benchmark dataset, and achieve 25.47% higher performance compared to the KLUE-RoBERTa-large model for the relation information extraction task. The results of this study are expected to contribute to AI research by showing the feasibility of extracting knowledge elements from Korean text. Furthermore, this methodology can be utilized for various fields and purposes, and has potential for building various Korean datasets.

• The Mathematical Education
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• v.63 no.2
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• pp.187-207
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• 2024

In this study, we explored the feasibility of automatically scoring descriptive assessment items using GPT-4 based ChatGPT by comparing and analyzing the scoring results between teachers and GPT-4 based ChatGPT. For this purpose, three descriptive items from the permutation and combination unit for first-year high school students were selected from the KICE (Korea Institute for Curriculum and Evaluation) website. Items 1 and 2 had only one problem-solving strategy, while Item 3 had more than two strategies. Two teachers, each with over eight years of educational experience, graded answers from 204 students and compared these with the results from GPT-4 based ChatGPT. Various techniques such as Few-Shot-CoT, SC, structured, and Iteratively prompts were utilized to construct prompts for scoring, which were then inputted into GPT-4 based ChatGPT for scoring. The scoring results for Items 1 and 2 showed a strong correlation between the teachers' and GPT-4's scoring. For Item 3, which involved multiple problem-solving strategies, the student answers were first classified according to their strategies using prompts inputted into GPT-4 based ChatGPT. Following this classification, scoring prompts tailored to each type were applied and inputted into GPT-4 based ChatGPT for scoring, and these results also showed a strong correlation with the teachers' scoring. Through this, the potential for GPT-4 models utilizing prompt engineering to assist in teachers' scoring was confirmed, and the limitations of this study and directions for future research were presented.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.4
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• pp.365-373
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• 2010

A chemical reactor model (CRM) was developed for a jet stirred reactor (JSR) to predict the emission of exhaust such as NOx. In this study, a two-PSR model was chosen as the chemical reactor model for the JSR. The predictions of NO formation in lean premixed methane-air combustion in the JSR were carried out by using CHEMKIN and GRI 3.0 methane-air combustion mechanism which include the four NO formation mechanisms. The calculated results were compared with Rutar's experimental data for the validation of the model. The effects of important parameters on NO formation and the contributions of the four NO pathways were investigated. In the flame region, the major pathway is the prompt mechanism, and in the post flame region, the major pathway is the Zelodovich mechanism. Under the lean premixed condition, the N2O mechanism is the important pathway in both flame and postflame regions.

• Journal of the Korean Institute of Gas
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• v.24 no.4
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• pp.39-47
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• 2020

Flue gas recirculation(FGR) is an effective combustion technique for reducing nitrogen oxides(NOx) and is applied in various fields of low-pollution combustion. Continuing the previous study, a numerical analysis was conducted to identify changes of flame characteristics and NOx formation mechanism with applying FGR technique in CH₄/air premixed counterflow flames. NOx emitted was divided into four main reaction paths(thermal NO, prompt NO, N₂H and N₂O), showing relatively the production rate of NO with the recirculation ratio. As a result, thermal NO contributed greatly to the overall NO whereas the effect of N₂H was minimal. In addition, emission index of NO was compared as the recirculation ratio increased by modifying the UC San Diego mechanism to examine the contribution of thermal NO.

• Proceedings of the Korean Society of Disaster Information Conference
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• 2015.11a
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• pp.321-323
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• 2015

This study will build a prompt response system based on accurate information about the internal structure of cultural heritages, including the roof structure, to improve the ability to contain and respond to the fire of wooden structure for safe preservation of cultural heritages with historical and academic values that are very vulnerable to fire, and develop a training simulation program based on virtual reality by applying the concept of Edutainment for systemized and interesting training of trainees with a response manual.

• International conference on construction engineering and project management
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• 2007.03a
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• pp.79-87
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• 2007

An effective logistics management is necessary for successful construction projects. So, prompt and precise logistics information collecting and management is needed, but there has been no systematic and effective method for this, Therefore, in this research, a standardized plan for RFID application in logistics management that could comprehend processes in building construction projects, was developed. With the 7 generalized process types that comprehend processes in construction projects, critical factors that should be considered for RFID applications were derived, and systematic and efficient application method for building projects were developed.