• Nuclear Engineering and Technology
• /
• v.55 no.5
• /
• pp.1593-1603
• /
• 2023

In deterministic and Monte Carlo transport codes, b-delayed emission is included using a group structure where all of the precursors are grouped together in 6 groups or families, but given the increase in computational power, nowadays there is no reason to keep this structure. Furthermore, there have been recent efforts to compile and evaluate all the available b-delayed neutron emission data and to measure new and improved data on individual precursors. In order to be able to perform a transient Monte Carlo simulation, data from individual precursors needs to be implemented in a transport code. This work is the first step towards the development of a tool to explore the effect of individual precursors in a fissile system. In concrete, individual precursor data is included by expanding the capabilities of the open source Monte Carlo code OpenMC. In the modified code - named Time Dependent OpenMC or OpenMC(TD)- time dependency related to β-delayed neutron emission was handled by using forced decay of precursors and combing of the particle population. The data for continuous energy neutron cross-sections was taken from JEFF-3.1.1 library. Regarding the data needed to include the individual precursors, cumulative yields were taken from JEFF-3.1.1 and delayed neutron emission probabilities and delayed neutron spectra were taken from ENDF-B/VIII.0. OpenMC(TD) was tested in a monoenergetic system, an energy dependent unmoderated system where the precursors were taken individually or in a group structure, and in a light-water moderated energy dependent system, using 6-groups, 50 and 40 individual precursors. Neutron flux as a function of time was obtained for each of the systems studied. These results show the potential of OpenMC(TD) as a tool to study the impact of individual precursor data on fissile systems, thus motivating further research to simulate more complex fissile systems.

• Steel and Composite Structures
• /
• v.24 no.2
• /
• pp.201-211
• /
• 2017

This study evaluates the reliability of present European codes in predicting the collapse load of columns made with perforated cold-formed steel (CFS) profiles under combined axial load and bending. To this aim, a series of experimental tests on slender open-section specimens have been performed at varying load eccentricity. Preliminarily, stub column tests have also been performed to calculate the effective section properties of the investigated profile. By comparison of experimental data with code-specified M-N strength domains, the authors demonstrate that present code formulations may underestimate the collapse load of thin-walled perforated open sections. The study is the first step of a wider experimental and numerical study aimed at better describing strength domains of perforated CFS open sections.

• Bulletin of the Korean Mathematical Society
• /
• v.55 no.2
• /
• pp.359-366
• /
• 2018

We extend Jung's result about the relations among bi-closing, open and constant-to-one codes between general shift spaces to closing codes. We also show that any closing factor code ${\varphi}:X{\rightarrow}Y$ has a degree d, and it is proved that d is the minimal number of preimages of points in Y. Some other properties of closing codes are provided. Then, we show that any closing factor code is hyperbolic. This enables us to determine some shift spaces which preserved by closing codes.

• International Journal of Advanced Culture Technology
• /
• v.8 no.2
• /
• pp.297-304
• /
• 2020

Recently, open source automatic machine learning solutions have been applied in many fields. To apply open source automated machine learning to real world problems, you need to write code with expertise in machine learning. Writing code without machine learning knowledge is challenging. To solve this problem, the automatic machine learning solutions provided by startups are made easy to use with a clean user interface. In this paper, we review automatic machine learning solutions of startups.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.39 no.8
• /
• pp.702-710
• /
• 2011

This paper aims to verify the applicability of OpenFOAM, the widely recognized open source CFD code, to external flows commonly found in aeronautical problems. To this end, several representative flow cases are selected first from subsonic to supersonic flow fields. Then, the computational results obtained from OpenFOAM are systematically compared against available data from experiments and other numerical codes. It was found that the strength and location of shock are well predicted and the effects of boundary conditions on the computed results are reviewed. Subsonic flow with massive separation is selected to validate the prediction capability of OpenFOAM. Based on the current results, the limitation and possibility of OpenFOAM was confirmed and for future study using OpenFOAM was suggested.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.10 no.6
• /
• pp.2648-2668
• /
• 2016

Modern mobile devices are equipped with various accelerated processing units to handle computationally intensive applications; therefore, Open Computing Language (OpenCL) has been proposed to fully take advantage of the computational power in heterogeneous systems. This article introduces a parallel software decoder of Low Density Parity Check (LDPC) codes on an embedded heterogeneous platform using an OpenCL framework. The LDPC code is one of the most popular and strongest error correcting codes for mobile communication systems. Each step of LDPC decoding has different parallelization characteristics. In the proposed LDPC decoder, steps suitable for task-level parallelization are executed on the multi-core central processing unit (CPU), and steps suitable for data-level parallelization are processed by the graphics processing unit (GPU). To improve the performance of OpenCL kernels for LDPC decoding operations, explicit thread scheduling, vectorization, and effective data transfer techniques are applied. The proposed LDPC decoder achieves high performance and high power efficiency by using heterogeneous multi-core processors on a unified computing framework.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.51 no.10
• /
• pp.190-196
• /
• 2014

This paper proposes a mobile-optimized pedestrian detection method using Cascade of HOG(Histograms of Oriented Gradients) for ADAS(Advanced Driver Assistance System) on smartphones. In order to use the limited resource of mobile platforms efficiently, the method is implemented by the OpenCL(Open Computing Language) library, and its processing time is reduced in the following two aspects. Firstly, the method sets a program build option specifically and adjusts work group sizes as variety of kernels in the host code. Secondly, it utilizes local memory and a LUT(Look-Up Table) in the kernel code to accelerate the program. For performance evaluation, the developed algorithm is compared with the mobile CPU-based OpenCV(Open Computer Vision) for Android function. The experimental results show that the processing speed is 25% faster than the OpenCV hogcascade.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.18 no.9
• /
• pp.425-435
• /
• 2017

Structural analysis is used not only for large enterprises, but also for small and medium sized ones, as a necessary procedure for strengthening the certification process for product delivery and shortening the time in the process from concept design to detailed design. Open-source solvers that can be used atlow cost differ from commercial solvers. If there is a problem with the input data, such as with the grid, errors or failures can occur in the calculation step. In this paper, we propose a pre- and post-processor that can be easily applied to the analysis of mechanical structural problems by using the existing structural analysis open source solver (Caculix, Code_Aster). In particular, we propose algorithms for analyzing different types of data using open source solvers in order to extract and generate accurate information,such as 3D models, grids and simulation conditions, and develop and apply information analysis. In addition, to improve the accuracy of open source solvers and to prevent errors, we created a grid that matches the solver characteristics and developed an automatic healing function for the grid model. Finally, to verify the accuracy of the system, the verification and utilization results are compared with the software used.

• Journal of KIISE:Computing Practices and Letters
• /
• v.16 no.9
• /
• pp.918-926
• /
• 2010

A widget is a small application running by the users' favorite services, so they are provided with web contents without explicitly visiting the web site. Although widgets can be easily implemented with Open APIs, only a few web sites provide them because of refactoring the structures of web resource to supply Open APIs to the widget developers. This paper presents an Open API Proxy Server System for widget services. The system consists of two components: an Open API Source Code Generator and an Open API Proxy Server. The Open API Source Code Generator provides a Graphical User Interface (GUI) for users to generate the Open APIs of user's choice and sends the Open API source code generation request to the Open API Proxy Server. The Open API Proxy Server using the HTML Table Processing Library receives the HTML web page from web site and extracts useful information from the target HTML table. The proxy server converts the extracted data into the corresponding XML document which becomes available through the Open API. We verify the operation of the proposed system through experiments with the HTML tables in the example web sites.

• International Journal of Naval Architecture and Ocean Engineering
• /
• v.6 no.4
• /
• pp.1024-1040
• /
• 2014

The theoretical background and a numerical solution procedure for a time domain hydroelastic code are presented in this paper. The code combines a VOF-based free surface flow solver with a flexible body motion solver where the body linear elastic deformation is described by a modal superposition of dry mode shapes expressed in a local floating frame of reference. These mode shapes can be obtained from any finite element code. The floating frame undergoes a pseudo rigid-body motion which allows for a large rigid body translation and rotation and fully preserves the coupling with the local structural deformation. The formulation relies on the ability of the flow solver to provide the total fluid action on the body including e.g. the viscous forces, hydrostatic and hydrodynamic forces, slamming forces and the fluid damping. A numerical simulation of a flexible barge is provided and compared to experiments to show that the VOF-based flow solver has this ability and the code has the potential to predict the global hydroelastic responses accurately.