• Nuclear Engineering and Technology
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• v.51 no.7
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• pp.1776-1783
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• 2019

To accurately analyze the accidents in nuclear reactors, a thermohydraulic-neutronic coupling calculation is required to solve fluid dynamics and nuclear reactor kinetics equations in fine cells simultaneously and evaluate the local effects of neutronic and thermohydraulic parameters on each other. In the present study, a 3D thermohydraulic-neutronic coupling model is developed, validated and then applied for Isfahan MNSR (Miniature Neutron Source reactor) safety analysis. The proposed model is developed using FLUENT software and user defined functions (UDF) are applied to simulate the neutronic behavior of MNSR. The validation of the proposed model is first evaluated using 1mk reactivity insertion experiment into Isfahan MNSR core. Then, the developed coupling code is applied for a design basis accident (DBA) scenario analysis with the insertion of maximum allowed cold core reactivity of 4 mk. The results show that the proposed model is able to predict the behavior of the reactor core under normal and accident conditions with a good accuracy.

• Journal of Software Assessment and Valuation
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• v.16 no.2
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• pp.1-8
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• 2020

The similarity detection to plagiarism or duplication of computer programs requires a different type of analysis methods and tools according to the programming language used in the implementation and the sort of code to be analyzed. In recent years, the similarity appraisal for the object code in the embedded system, which requires a considerable resource along with a more complicated procedure and advanced skill compared to the source code, is increasing. In this study, we described a method for analyzing the similarity of functional units in the assembly language through the conversion of object code using the reverse engineering approach, such as the reverse assembly technique to the object code. The instruction and operand table for comparing the similarity is generated by using the syntax analysis of the code in assembly language, and a tool for detecting the similarity is designed.

• Tunnel and Underground Space
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• v.32 no.2
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• pp.144-159
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• 2022

The present study developed a sequential approach-based numerical simulator for modeling coupled thermal-hydrological-mechanical (THM) processes in the ground and investigated the computational performance of the coupling analysis algorithm. The present sequential approach linked the two different solvers: an open-source numerical code, OpenGeoSys for solving the thermal and hydrological processes in porous media and a commercial code, FLAC3D for solving the geomechanical response of the ground. A benchmark test of the developed simulator was carried out using a THM problem where an analytical solution is given. The benchmark problem involves the coupled behavior (variations in temperature, pore pressure, stress, and deformation with time) of a fully saturated porous medium which is subject to a point heat source. The results of the analytical solution and numerical simulation were compared and the validity of the numerical simulator was investigated.

• Journal of Information Technology Services
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• v.11 no.4
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• pp.251-262
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• 2012

Unit testing is one of the test levels, which tests an individual unit or a group of related units. Recently, in Agile Development or Safety-critical System Development, the unit testing plays an important role for the qualities. According to the definition of unit testing, it is supposed to be done by the developers of units. That is because test models for the unit testing refers to the structure of units, and others but its original developers hardly can understand the structures. However, in practice, unit testing is often asked to be done without the original developers. For example, it is when faults are revealed in customer sites and the development team does not exit any more. In this case, instead of original developers, other developers or test engineers take a product and test it. The unit testing done by a non-developer, who is not the original developer, would cause some difficulties or cause more cost. In this paper, we tests an open source, JTopas, as a non-developer, with building test models, implementing test codes, and executing test cases. To fit this experiment to practical testing situations, we designed it based on the practices of unit testing, which were surveyed through SPIN(Software Process Improvement Network). This paper analyzes which part of unit testing done by non-developers needs more effort compared to the unit testing done by original developers. And it concludes that Agile Development contributes on reducing the extra effort caused by non-developers, since it implements test codes first before developing source code. That means all the units have already included their own tests code when they are released.

• The Journal of the Korea Contents Association
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• v.10 no.5
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• pp.70-79
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• 2010

We perform static program analysis for the binary code. The reason you want to analyze at the level of binary code, installed on your local computer, run the executable file without source code. And the reason we want to perform static analysis, static program analysis is to understand what actions to perform on your local computer. In this paper, execution flow graph representing information such as the execution order among functions and the flow of control is generated. Using graph, User can find execution flow of binary file and calls of insecure functions at the same time, and the graph should facilitate the analysis of binary files. In addition, program to be run is ensured the safety by providing an automated way to search the flow of execution, and program to be downloaded and installed from outside is determined whether safe before running.

• Nuclear Engineering and Technology
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• v.54 no.7
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• pp.2670-2689
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• 2022

STREAM - a lattice transport calculation code with method of characteristics for the purpose of light water reactor analysis - has been developed by the Computational Reactor Physics and Experiment laboratory (CORE) of the Ulsan National Institute of Science and Technology (UNIST). Recently, efforts have been taken to develop a photon module in STREAM to assess photon heating and the influence of gamma photon transport on power distributions, as only neutron transport was considered in previous STREAM versions. A multi-group photon library is produced for STREAM based on the ENDF/B-VII.1 library with the use of the library-processing code NJOY. The developed photon solver for the computation of 2D and 3D distributions of photon flux and energy deposition is based on the method of characteristics like the neutron solver. The photon library and photon module produced and implemented for STREAM are verified on VERA pin and assembly problems by comparison with the Monte Carlo code MCS - also developed at UNIST. A short analysis of the impact of photon transport during depletion and thermal hydraulics feedback is presented for a 2D core also from the VERA benchmark.

• Proceedings of the Korea Information Processing Society Conference
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• 2024.05a
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• pp.53-56
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• 2024

Though lots of approaches to develop mobile apps are suggested up to now, developers have difficulties selecting a right one. This study compares native and cross-platform application development approaches, particularly focusing on the shift in preference from Java to Kotlin and the increasing use of Flutter. This research offers practical insights into factors influencing developers' choice of programming languages and frameworks in mobile application development by creating identical applications using Java, Kotlin, and Dart (Flutter). Furthermore, this study explores the best practices for development by examining the quality of code in 45 open-source GitHub repositories. The study evaluates LOC and code smells using semi-automated SonarQube assessments to determine the effects of selecting a specific language or framework on code maintainability and development efficiency. Preliminary findings show differences in the quality of the code produced by the two approaches, offering developers useful information on how to best optimize language and framework selection to reduce code smells and improve project maintainability.

• Nuclear Engineering and Technology
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• v.50 no.1
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• pp.182-189
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• 2018

A neutron generation system was developed to induce fissile fission in a lead slowing down spectrometer (LSDS) system. The source neutron is one of the key factors for LSDS system work. The LSDS was developed to quantify the isotopic contents of fissile materials in spent nuclear fuel and recycled fuel. The source neutron is produced at a multilayered target by the (e,${\gamma}$)(${\gamma}$,n) reaction and slowed down at the lead medium. Activation analysis of the target materials is necessary to estimate the lifetime, durability, and safety of the target system. The CINDER90 code was used for the activation analysis, and it can involve three-dimensional geometry, position dependent neutron flux, and multigroup cross-section libraries. Several sensitivity calculations for a metal target with different geometries, materials, and coolants were done to achieve a high neutron generation rate and a low activation characteristic. Based on the results of the activation analysis, tantalum was chosen as a target material due to its better activation characteristics, and helium gas was suggested as a coolant. In addition, activation in a lead medium was performed. After a distance of 55 cm from the lead surface to the neutron incidence, the neutron intensity dramatically decreased; this result indicates very low activation.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.30 no.6
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• pp.1225-1236
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• 2020

Fuzzing is an automated software testing methodology that dynamically tests the security of software by inputting randomly generated input values outside of the expected range. KISA is releasing open source for standard cryptographic algorithms, and many crypto module developers are developing crypto modules using this source code. If there is a vulnerability in the open source code, the cryptographic library referring to it has a potential vulnerability, which may lead to a security accident that causes enormous losses in the future. Therefore, in this study, an appropriate security policy was established to verify the safety of block cipher source codes such as SEED, HIGHT, and ARIA, and the safety was verified using differential fuzzing. Finally, a total of 45 vulnerabilities were found in the memory bug items and error handling items, and a vulnerability improvement plan to solve them is proposed.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.9
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• pp.1932-1938
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• 2011

Public source code distribution form is done by mainly by limited class user and it was too hard to install. But companies are increasing who distribute software as open source, mass of people's interest also became high and it is coming about installation related methods have been changing. Not only traditional compile based installation, it is entrance on the stage of user friendly technique that is package installation, network based install, file execution after uncompression and cmake method to give easily to developer various platform support. This paper will analyze open source operating system Linux based public open source distributed application installation trend.