• Journal of Digital Contents Society
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• v.7 no.3
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• pp.183-191
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• 2006

Currently, the preferred processing of a user-centered ROI(Region-of-Interest) or a specific region of image to transmission and decompression of a full image is needed in different applications, specifically mobile applications. Here, we have to study how different factors affect ROI coding methods. Therefore, an application can select an ROI coding method and several parameters suitable for the environments. The ROI coding methods used in the study are Maxshift and Implicit and the parameters are tile size, image size, code block size, ROI importance and the number of lowest resolution levels. This study shows the experimental results between the different parameters and the two ROI coding methods.

• International Journal of Computer Science & Network Security
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• v.22 no.4
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• pp.73-82
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• 2022

This paper shows the hiding process of unlimited secret text size in an image using three methods: the first method is the traditional method in steganography that based on the concealing the binary value of the text using the least significant bits method, the second method is a new method to hide the data in an image based on Exclusive OR process and the third one is a new method for hiding the binary data of the text into an image (that may be grayscale or RGB images) using Exclusive and Huffman Coding. The new methods shows the hiding process of unlimited text size (data) in an image. Peak Signal to Noise Ratio (PSNR) is applied in the research to simulate the results.

• Structural Engineering and Mechanics
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• v.50 no.3
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• pp.323-347
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• 2014

This paper proposes a Particle Swarm Optimization (PSO) algorithm, which is improved by making use of the Harmony Search (HS) approach and called HS-PSO algorithm. A computer code is developed for optimal sizing design of non-linear steel frames with various semi-rigid and rigid beam-to-column connections based on the HS-PSO algorithm. The developed code selects suitable sections for beams and columns, from a standard set of steel sections such as American Institute of Steel Construction (AISC) wide-flange W-shapes, such that the minimum total cost, which comprises total member plus connection costs, is obtained. Stress and displacement constraints of AISC-LRFD code together with the size constraints are imposed on the frame in the optimal design procedure. The nonlinear moment-rotation behavior of connections is modeled using the Frye-Morris polynomial model. Moreover, the P-${\Delta}$ effects of beam-column members are taken into account in the non-linear structural analysis. Three benchmark design examples with several types of connections are presented and the results are compared with those of standard PSO and of other researches as well. The comparison shows that the proposed HS-PSO algorithm performs better both than the PSO and the Big Bang-Big Crunch (BB-BC) methods.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.25 no.5
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• pp.1021-1026
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• 2015

Increasing of damage by phishing, government and organization response more rapidly. So phishing use malware and vulnerability for attack. Recently attack that use patch analysis is increased when Microsoft announce patches. Cause of that, researcher for security on defense need technology of patch analysis. But most patch analysis are develop for Microsoft's product. Increasing of mobile environment, necessary of patch analysis on mobile is increased. But ordinary patch analysis can not use mobile environment that there is many file and small size. So we suggest this research that use code filtering instead of Control Flow Graph and Abstract Syntax Tree.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.12
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• pp.7350-7356
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• 2014

To study the reasonable design thermal loads, a steel box girder bridge specimen, which has no concrete slab, was manufactured with real size dimensions. The temperature data was obtained at the web and diaphragm using thermo gauges that were attached according to height. In the hottest day, the temperature differences between the top and bottom of the bridge model were calculated. The temperatures in the actual bridge were measured and the temperature of the bridge specimen was compared. The temperature gradient models were proposed in both the web and the diaphragm. The proposed models showed a correlation of approximately 95.8% compared to the Euro code. This study can provide basis data for temperature-load design in the nation.

• Special Issue of the Society of Naval Architects of Korea
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• 2017.10a
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• pp.93-104
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• 2017

IMO type C independent tank is one of the cargo containment system specified on IGC code. It is normally adopted for small and medium size liquefied gas carrier's cargo containment system and it can be applied to fuel tank of LNG fueled vessel. This study focuses on rule scantling process and evaluation methods in early design stage of type C independent tank. Actual design results of 22K LPG/Ammonia/VCM carrier's No.2 cargo tank are demonstrated. This paper presents the calculation methods of design acceleration and liquid height for internal design pressure as defined on IGC code. And this paper shows the applied results of classification rules about shell thickness requirement and buckling strength. Additionally this paper deals with evaluation methods of structural strength and cumulative fatigue damage using FE analysis.

• Journal of computational fluids engineering
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• v.20 no.1
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• pp.1-9
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• 2015

A developed code is applied to simulate relative motion of floating bodies in a side-by-side arrangement, including effects of a fender and a hawser. The developed code is based on the flux-difference splitting scheme for immiscible incompressible fluids and the hybrid Cartesian/immersed boundary method. To validate the developed code for free surface flows around deforming boundaries, the water wave generation is simulated, which is caused by bed movement. The computed wave profile and time histories of wave elevation are compared with other experimental and computational results. The effects of a fender and a hawser are modeled by asymmetric force acting on the floating bodies according to a relative displacement with the bounds, in which the fender and the hawser exert no force on the bodies. It has been observed that the floating body can be accelerated by a gap flow due to a phase difference caused by the free surface. Grid independency is established for the computed time history of the body velocity, based on three different size grids.

• Journal of the Society of Naval Architects of Korea
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• v.45 no.5
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• pp.523-529
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• 2008

The course stability performance for tankers is evaluated by computational fluid dynamics. In the present work, a Reynolds averaged Navier-Stokes (RANS) code is applied to a maneuvering problem covering the pure drift and yaw motions. The purposes of this study are to evaluate the hydrodynamic force in the bare hull (AFRAMAX) in pure drift and yaw motion and to provide information about the trends in the forces and moments when the rudder angles are varied. The flow simulation is performed by FLUENT. The CFD code is examined to find the optimistic computational condition such as size of grid, turbulence model and initial condition. The hydrodynamic derivatives in drift and pure yaw motion are estimated by the numerical simulation, and then the stability levers are calculated. It is confirmed that the computations show the superiority and inferiority of course stability performance according to the hull forms. Finally, the CFD code is applied to the estimation of the rudder forces when the rudder angles are varied. The propeller effect expressed by the body force distribution is also included.

• Structural Engineering and Mechanics
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• v.46 no.5
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• pp.735-753
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• 2013

The wind load is always the dominant load of cooling tower due to its large size, complex geometry and thin-wall structure. At present, when computing the wind-induced response of the large-scale cooling tower, the wind pressure distribution is obtained based on code regulations, wind tunnel test or computational fluid dynamic (CFD) analysis, and then is imposed on the tower structure. However, such method fails to consider the change of the wind load with the deformation of cooling tower, which may result in error of the wind load. In this paper, the analysis of the large cooling tower based on the iterative method for wind pressure is studied, in which the advantages of CFD and finite element method (FEM) are combined in order to improve the accuracy. The comparative study of the results obtained from the code regulations and iterative method is conducted. The results show that with the increase of the mean wind speed, the difference between the methods becomes bigger. On the other hand, based on the design of experiment (DOE), an approximate model is built for the optimal design of the large-scale cooling tower by a two-level optimization strategy, which makes use of code-based design method and the proposed iterative method. The results of the numerical example demonstrate the feasibility and efficiency of the proposed method.

• Health Policy and Management
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• v.11 no.1
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• pp.37-61
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• 2001

In the course of this research, we developed FRIS(Food Replica Information System), which calculates calories and nutrient values of foods in a very simple and interesting manner, and experienced of application to some communities. We expect that individuals will have opportunities to raise their consciousness of food, nutrients, and healthy living by participating in FRIS. 154 kinds of commonly consumed Korean foods were selected and one serving sized food replicas, having the same shapes, size, and color as the real foods, were constructed with attached bar code labels. An application program with food replicas and bar code was also developed in order to provide information on calories and nutrient values for people's meals or selected foods based on survey results of housewives' requirements related to foods and nutrients. FRIS should be a basic tool in nutrition education and consultation. Its applicability would vary according to the nutritionist's flexibility and contents of developed application programs. Technical stability should be strengthened and more useful contents of application prograln be added to spread the use of the system. Additionally, in future research, more delicate models should be developed and an analytical method should be applied to examine the effects of FRIS to individual behavioral changes in their eating habits.