• Bulletin of the Society of Naval Architects of Korea
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• v.24 no.2
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• pp.47-54
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• 1987

Linear and nonlinear hydrodynamic force, which acts on submerged circular and eilliptic cylinders in oscillations as well as in advancing motion, are investigated as an initial-boundary value problem using a numerical method, which makes use of the source distribution on the body surface and the spectral method for treating the free surface waves. In the numerical code developed here, the boundary condition at the body surface is linearized. Using the numerical code so attained, nonlinear effects for different forward speeds and of the large-amplitude motion are computed. One of the major findings is that, when the forward speed is large, the added mass has its minimum and the damping force change rapidly around the frequency corresponding to the speed-frequency parameter, $\tau$=0.25, Compared to the result of Grue's [10], who used linear theory to get abrupt changes in values of the added mass and the damping force at the frequency corresponding to $\tau$=0.25, the present study, which takes nonlinear effects into account, shows much smoother variations near the frequency.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.10
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• pp.892-897
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• 2017

As the weapon system SW development and management manual of the DAPA, which is the regulation for the overall weapon system SW development, is revised, the level and scope of SW reliability test are upgraded to improve the reliability and quality of SW. It is a big burden for SW developers. In particular, the dynamic test requires a schedule and manpower required to implement the weapon system SW, and should be performed every time the source code changes, not just one time. In this paper, we propose a regression test automation program(VectorCast Environment Manager) that performs a dynamic test using VectorCast, a dynamic test tool, and then performs a regression test automatically by minimizing human intervention in the regression test of dynamic test due to the change of the source code.

• Nuclear Engineering and Technology
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• v.56 no.4
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• pp.1425-1430
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• 2024

This study develops superheated emulsion detectors that are both sensitive to fast neutrons, and thermal neutrons owing to the exergonic ⁶₃Li(n, α)³₁H capture reaction caused by the ⁶Li-containing compound dispersed throughout the gel-like medium. The experimental research was conducted on two SEDs. One detector was an ordinary Freon-12 detector and the other was a Freon-12 detector containing 3.4 % (by weight) LiCl. In order to investigate the sensitivity of lithium-containing SEDs to thermal neutrons, two types of SEDs were simultaneously exposed to various flux levels of thermal neutrons from ²⁴¹Am-Be neutron source inside a cylindrical tank filled with water. A Boron-lined proportional counter was used to estimate the thermal neutron flux and the relevant MCNP code was developed for flux and dose calculations in the prepared set-up around ²⁴¹Am-Be source. The results demonstrate that there is a proportional relationship between the variations of SED response and the change in thermal neutron flux and dose. Also, the sensitivity of SED was estimated.

• Journal of the Korean Society for Railway
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• v.11 no.3
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• pp.294-299
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• 2008

The present study investigates the ventilation effects on smoke spreading with the rescue stations. Experiments for tunnel fires were carried out for n-heptane pool em at different fire locations, and the heat release rates (HRR) were obtained by addition, using the commercial code (FLUENT), the present article presents numerical results for smoke behavior in railway tunnels with rescue station, and it uses the MVHS (Modified Volumetric Heat Source) model for estimation of combustion products resulting from the fire source determined from the HRR measurement. As a result, it is found that smoke propagation is prevented successfully by the fire doors located inside the cross-passages and especially, the smoke behavior in the accident tunnel can be controlled through the ventilation system because of substantial change in smoke flow direction in the cross-passages.

• Journal of Internet Computing and Services
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• v.3 no.4
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• pp.83-94
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• 2002

Recently for software development productivity a lot of researches in the field of software engineering hove focuses on the component-based software product lines which allows the reuse of forger-granularity software components Its purpose is to develop the specific software application of quality more rapidly by instantiating and assembling the components populated in software product line assets The essential part to build the component-based software product lines is the quality of components, and one of the most important features determining the quality of components is 'reconfigurability' Component reconfigurability means the extent to which the reusers can change the functions and architecture of the component according to their context and environment. This paper proposes the component code generation technique which provides the reconfigurability at the time of code generation using The feature diagram and XML/XSLT technologies The approach of this paper allows the component reusers to get automatically their own component source code by providing only the values of variabilities represented in the feature diagram of the component family. The real world example, the code generation system for o list container family, shows the applicability of the feature model and XML related technologies in the area of the generative programming. Our approach should be basis to build the component based software product lines and extensible to support the larger graularity components.

• Journal of KIISE
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• v.43 no.12
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• pp.1334-1341
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• 2016

In recent years, the importance of managing software defects in the implementation stage has emerged because of the rapid development and wide-range usage of intelligent smart devices. Even if not a few studies have been conducted on the prediction models for software defects, their outcomes have not been widely shared. This paper proposes an efficient probabilistic management model of software metrics based on the Bayesian network, to overcome limits such as binary defect prediction models. We expect the proposed model to configure the Bayesian network by taking advantage of various software metrics, which can help in identifying improvements for refactoring. Once the source code has improved through code refactoring, the measured related metric values will also change. The proposed model presents probability values reflecting the effects after defect removal, which can be achieved by improving metrics through refactoring. This model could cope with the conclusive binary predictions, and consequently secure flexibilities on decision making, using indeterminate probability values.

• Journal of Korean Society for Atmospheric Environment
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• v.29 no.6
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• pp.838-848
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• 2013

The Community Multiscale Air Quality (CMAQ) model is capable of providing high quality atmospheric chemistry profiles through the utilization of high-resolution meteorology and emissions data. However, it cannot simulate air quality accurately if input data are not appropriate and reliable. One of the most important inputs required by CMAQ is the air pollutants emissions, which determines air pollutants concentrations during the simulation. For the CMAQ simulation of Korean peninsula, we, in general, use the Korean National Emission Inventory data which are estimated by Clean Air Policy Support System (CAPSS). However, since they are not provided by model-ready emission data, we should convert CAPSS emissions into model-ready data. The SMOKE is the emission model we used in this study to generate CMAQ-ready emissions. Because processing the emissions data is very monotonous and tedious work, we have developed CAPSS2SMOKE program to convert CAPSS emissions into SMOKE-ready data with ease and effective. CAPSS2SMOKE program consists of many codes and routines such as source classification code, $PM_{10}$ to $PM_{2.5}$ ratio code, map projection conversion routine, spatial allocation routine, and so on. To verify the CAPSS2SMOKE program, we have run SMOKE using the CAPSS 2009 emissions and found that the SMOKE results inherits CAPSS emissions quite well.

• Journal of the Korean Geotechnical Society
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• v.30 no.9
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• pp.67-75
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• 2014

Methane gas hydrate which is considered energy source for the next generation has an urgent need to develop reliable numerical simulator for coupled THM phenomena in the porous media, to minimize problems arising during the production and optimize production procedures. International collaborations to improve previous numerical codes are in progress, but they still have mismatch in the predicted value and unstable convergence. In this paper, FEM code for fully coupled THM phenomena is developed to analyze methane hydrate dissociation in the porous media. Coupled partial differential equations are derived from four mass balance equations (methane hydrate, soil, water, and hydrate gas), energy balance equation, and force equilibrium equation. Five main variables (displacement, gas saturation, fluid pressure, temperature, and hydrate saturation) are chosen to give higher numerical convergence through trial combinations of variables, and they can analyze the whole region of a phase change in hydrate bearing porous media. The kinetic model is used to predict dissociation of methane hydrate. Developed THM FEM code is applied to the comparative study on a Masuda's laboratory experiment for the hydrate production, and verified for the stability and convergence.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.7
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• pp.1626-1633
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• 2010

In this paper, we implemented medicinal plant information system based on user requirement using Ajax technique which can retrieve data from the server asynchronously in the background without refresh webpage and jQuery which is a lightweight cross-browser javascript library. Also, we presented the source code handling the server response data used in the system and compared the features by the type of response data. This system shows the improvement of user interaction and response rates because of a simple response data from the server, client-side data processing and change of web page by manipulating the DOM tree and provides ease of use and convenient data access.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.10
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• pp.831-835
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• 2020

By automatically generating HDL codes from C/C++ source codes, HLS makes it possible to shorten FPGA system developing period through easy timing control and structure change. We designed LDPC encoder for telemetry standard 106-17 with Xilinx Vivado HLS and showed hardware structure can be easily adapted for different purposes through minor C code modification. Synthesis results targeting Spartan-7 xc7s100 device are presented for throughput and hardware complexity comparison.