• 한국전산유체공학회:학술대회논문집
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• 2011.05a
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• pp.327-330
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• 2011

CFD simulation is widely used in various industries, universities and research centers. In Korea most of the researchers use foreign commercial S/W packages especially in industries. But commercial CFD packages have some problems as limit to source code and very high license foe. So from several years ago open source CFD code has been widely spread as an alternative. But in Korea there are a few users of open source code. Insufficiency of performance validation as for accuracy, robustness, convenience and parallel speed-up is important obstacles of open source code. So we tested some validation cases as to incompressible external aerodynamics and internal flaws and now are doing compressible flaws. As the first stage of compressible flow validation, we simulated Korea next generation high speed train(HEMU). It's running condition is 400km/hr and maximum Mach number reaches up to 0.4. With the high speed train we tested accuracy, robustness and parallel performance of open source CFD code OpenFOAM Because there isn't experimental data we compared results with widely used commercial code. When use $1^{st}$ order upwind scheme aerodynamic forces are very similar to commercial code. But using $2^{nd}$ order upwind scheme there was some discrepancy. The reason of the difference is not clear yet. Mesh manipulation, domain decomposition, post-processing and robustness are satisfactory. Paralle lperformance is similar to commercial code.

• Nuclear Engineering and Technology
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• v.55 no.9
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• pp.3388-3400
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• 2023

Detailed analysis of the neutron pathway through matter inside the nuclear reactor core is exceedingly needed for safety and economic considerations. Due to the constant development of high-performance computing technologies, neutronics analysis using computer codes became more effective and efficient to perform sophisticated neutronics calculations. In this work, a commercial pressurized water reactor (PWR) presented by Virtual Environment for Reactor Applications (VERA) Core Physics Benchmark are modeled and simulated using a high-fidelity simulation of OpenMC code in terms of criticality and fuel pin power distribution. Various problems have been selected from VERA benchmark ranging from a simple two-dimension (2D) pin cell problem to a complex three dimension (3D) full core problem. The development of the code capabilities for reactor physics methods has been implemented to investigate the accuracy and performance of the OpenMC code against VERA SCALE codes. The results of OpenMC code exhibit excellent agreement with VERA results with maximum Root Mean Square Error (RMSE) values of less than 0.04% and 1.3% for the criticality eigenvalues and pin power distributions, respectively. This demonstrates the successful utilization of the OpenMC code as a simulation tool for a whole core analysis. Further works are undergoing on the accuracy of OpenMC simulations for the impact of different fuel types and burnup levels and the analysis of the transient behavior and coupled thermal hydraulic feedback.

• Journal of KIISE:Software and Applications
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• v.36 no.3
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• pp.244-251
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• 2009

We present a transformation which converts open-code multi-staged programs into closed ones. Staged computation, which explicitly divides a computation into separate stages, is a unifying framework for existing program generation systems. Because a multi-staged program generates another program, which can also generate a third program and on, the implementation of a multi-staged language is not straightforward. Dynamic binding of (lexically free) variables in code also makes the implementation of a multi-staged language hard. By converting each code into code of function which takes environment for free variables as its argument and giving an actual environment at the code-composition site, we can transform a open-code program into a closed-code one. Combining with Davies and Pfenning's method, our closed-code-conversion enables the implementation of the unstaged language to be useful for executing multi-staged programs. We also prove the correctness of our conversion: the converted program is equivalent to the original program, and the converted program does not have open code.

• Nuclear Engineering and Technology
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• v.54 no.3
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• pp.811-816
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• 2022

This work presents the methodology used to expand the capabilities of the Monte Carlo code OpenMC for the calculation of reactor kinetic parameters: effective delayed neutron fraction β_eff and neutron generation time L. The modified code, OpenMC(Time-Dependent) or OpenMC(TD), was then used to calculate the effective delayed neutron fraction by using the prompt method, while the neutron generation time was estimated using the pulsed method, fitting Λ to the decay of the neutron population. OpenMC(TD) is intended to serve as an alternative for the estimation of kinetic parameters when licensed codes are not available. The results obtained are compared to experimental data and MCNP calculated values for 18 benchmark configurations.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.10a
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• pp.317-320
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• 2016

In embedded system, if firmware code is opened by other company, must devise hardware copy prevention. That guard valuable product. Not used security IC, Suggested platform is source code open method that prevent core code and hardware copy. And that open firmware code for other company programmer. Suggest system security platform based on Corex-M3. that consist of IAP(In-application programing) and APP(Applicataion). IAP contain core code and security confirm code. APP is implement by other company developer using core function prototype.

• Journal of the Korea Society of Computer and Information
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• v.17 no.1
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• pp.87-95
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• 2012

In this paper, we propose a mobile book management application using the camera of a smart phone and the open API book information provided online. The camera automatically scans the bar-code or QR-code of a particular book. The code of that book is used to transmit detailed information to the open API. Then the proposed application records this information for use in an "Scan list" or an "My book list". This application notes the page of the book that the user is currently reading and, if the user has read the entire book, he or she can comment about it. Therefore, the proposed application provides useful functions so that the users can manage their books effectively.

• Journal of Advanced Research in Ocean Engineering
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• v.3 no.2
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• pp.75-82
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• 2017

With the development of computational fluid dynamics (CFD), studies on shipbuilding and maritime issues including free-surface wave flow have been conducted. Although the volume of fluid (VOF) and level-set methods are widely used to study the free-surface wave flow, disadvantages exist. In particular, it takes a long time to obtain solutions. In this study, a free-surface capturing code is developed for ship and offshore structures. The developed code focuses on accuracy and computation time. Open source CFD libraries, termed OpenFOAM, are used to develop the code. The results obtained using the developed code are compared with those obtained using interFoam. The results show that the developed code could be used to capture the free-surface wave flow without numerical diffusion; moreover, the accuracy of the developed code is largely the same as that of interFoam.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.8
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• pp.1116-1120
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• 2014

With the shift of the energy paradigm from supply side management to demand side management, demand resource management and demand response plays an important role in the energy industry. As a consequency, a lot of researches have been done to provide a suitable demand response system. However, most of the demand response systems are based on the propriety products that cannot be modified. In this paper, we are proposing an automated demand response system using an EnerNOC provided open source code. We implemented the demand response server (VTN) and demand response client (VEN), and validated the OpenADR2.0 compliances using the open source code. We also used an Arduino microcontoller to demonstrate the communication schemes to control various devices.

• Journal of the Korea Society of Computer and Information
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• v.17 no.10
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• pp.11-23
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• 2012

To achieve efficient code size reduction, this paper proposes a new compressed instruction set architecture for the OpenRISC architecture. The new instructions and their corresponding formats are designed by the profiling information of the existing instruction usage. New 16-bit instructions and 32-bit instructions are proposed to compressed the existing 32-bit instructions and instruction sequences, respectively. The proposed instructions can be classified into three types. The first is the new 16-bit instructions for the frequent normal 32-bit instructions such as add, load, store, branch, and jump instructions. The second type is the new 32-bit instructions for the consecutive two load instructions, two store instructions, and 32-bit data mov instructions. Finally, two new 32-bit instructions are proposed to compress function prolog and epilog code, respectively. OpenRISC hardware decoder is extended to support the new instructions. Experiments show that the efficiency of code size reduction improves by an average of 30.4% when compared to the OR1200 instruction set architecture without loss of execution performance.

• Korean Journal of Computational Design and Engineering
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• v.19 no.3
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• pp.224-235
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• 2014

Recently, Productivity of the construction industry has been decreasing than other industries. Because of this, BIM is being spread in the construction industry. However, quality criteria for BIM data is insufficient. Regulation information is an important factor for initial architectural design evaluations. However, building code and related regulation are numerous. National building code structure in Korea is much more complex than other countries. The purpose of this study is to suggest the typology method of building code and apply to real regulations. To achieve this purpose, the authors have extracted required information to from original regulation for code checking and suggested mapping methods between extracted information and information of IFC scheme. In addition, the authors have represented EXPRESS-G diagram for extracting information from IFC scheme and suggested code checking method through stair case. Output of this study can be used as a base line data for automated code checking system based on open BIM. Automated code checking system will be utilized in architectural design evaluations and supported to increase design quality. It can be used to mount in SEUMTER that is the construction administration system of Ministry of Land, Infrastructure and Transport (MOLIT).