• Journal of the Korean Society for Heat Treatment
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• v.2 no.2
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• pp.1-10
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• 1989

In this study, the specimens of SCM 22 H steel were quenched in oil and water baths at various agitation conditions in order to investigate the effects of quenchants and agitation conditions on the quench-hardening. A multi-channel temperature measurement apparatus was employed to obtain the cooling curves at several predetermined positions of specimens. Microstructural observation and hardness test were also carried out. Computer simulation of heat treating process was carried out using the modified finite difference method. Prediction of thermal history and hardness distribution by 2-dimensional computer analysis was in good agreement with the experimental results. It was found that the quantitative design of heat treating process can be made by the computer aided heat-treating analysis.

• Journal of the Korean Geophysical Society
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• v.8 no.1
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• pp.39-43
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• 2005

For the calculation of internal stability, the hypothesis in conventional design is on the basis of two distinct zones, which are 'active zone' and 'passive zone'. This means that there is an abrupt discontinuous transition from active to passive states across a potential failure line. The existence of a discontinuity of this nature appears physically unreasonable, especially from kinematic considerations. A series of pull-out model tests was undertaken from a wall being rotated about the toe to find the strain istribution mobilized from near the wall face into the deep, stable zone through the centre plane. With this finding of transition zone, the objective of study is aiming at identifying the likely effect of this zone in designing method by comparing with the prevailing design method.

• Journal of the Korean Institute of Navigation
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• v.16 no.1
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• pp.37-64
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• 1992

A study on the changes of the oceanographical environment caused by Mokpo coastal zone development was carried out. Special emphasis was placed on the clarification of the water level changes and coastal current structure and influence of the environmental factors on the coastal area. In order to understand the structure oceangraphical environemnt, such as water temperature, salinity, suspended solids, pH, dissolved oxygen, chemical oxygen demand, biochemical oxygen demand, distribution of bottom sediment, tide and current were measured. To investigated the structure of tide and current for the future development, a numerical analysis was carried out. In certain zones, it was found to be flooding problems near the lowlying commercial area.

• Nuclear Engineering and Technology
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• v.43 no.6
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• pp.489-498
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• 2011

UK National Nuclear Laboratory's (NNL's) version of the ENIGMA fuel performance code is described, including details of the development history, the system modelled, the key assumptions, the thermo-mechanical solution scheme, and the various incorporated models. The recent development of ENIGMA in the areas of whole core analysis and dry storage applications is then discussed. With respect to the former, the NEXUS code has been developed by NNL to automate whole core fuel performance modelling for an LWR core, using ENIGMA as the underlying fuel performance engine. NEXUS runs on NNL's GEMSTONE high performance computing cluster and utilises 3-D core power distribution data obtained from the output of Studsvik Scandpower's SIMULATE code. With respect to the latter, ENIGMA has been developed such that it can model the thermo-mechanical behaviour of a given LWR fuel rod during irradiation, pond cooling, drying, and dry storage - this involved: (a) incorporating an out-of-pile clad creep model for irradiated Zircaloy-4; (b) including the ability to simulate annealing out of the clad irradiation damage; (c) writing of additional post-irradiation output; (d) several other minor modifications to allow modelling of post-irradiation conditions.

• Asia pacific journal of information systems
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• v.31 no.3
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• pp.335-357
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• 2021

As reproduction of images can be done with ease, copy detection has increasingly become important. In the duplication process, image modifications are likely to occur and some alterations are deliberate and can be viewed as attacks. A wide range of copy detection techniques has been proposed. In our study, content-based copy detection, which basically applies DCT-based features for images, namely, pixel values, edges, texture information and frequency-domain component distribution, is employed. Experiments are carried out to evaluate robustness and sensitivity of DCT-based features from attacks. As different types of DCT-based features hold different pieces of information, how features and attacks are related can be shown in their robustness and sensitivity. Rather than searching for proper features, use of robustness and sensitivity is proposed here to realize how the attacked features have changed when an image attack occurs. The experiments show that, out of ten attacks, the neural networks are able to detect seven attacks namely, Gaussian noise, S&P noise, Gamma correction (high), blurring, resizing (big), compression and rotation with mostly related to their sensitive features.

• Journal of applied mathematics & informatics
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• v.10 no.1_2
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• pp.175-191
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• 2002

The equations of a polar fluid of hydromagnetic fluctuating through a porous medium axe cast into matrix form using the state space and Laplace transform techniques the resulting formulation is applied to a variety of problems. The solution to a problem of an electrically conducting polar fluid in the presence of a transverse magnetic field and to a problem for the flow between two parallel fixed plates is obtained. The inversion of the Laplace transforms is carried out using a numerical approach. Numerical results for the velocity, angular velocity distribution and the induced magnetic field are given and illustrated graphically for each problems.

• Biomedical Science Letters
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• v.10 no.2
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• pp.129-135
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• 2004

The study was carried out through measuring the temperature and humidity of the indoor/outdoor space and the distribution of interior thermal condition, and investigating the effect of loess materials on human body. The purpose of this study is to analyze the change of dry bulb temperature and relative humidity and correlation of thermal reaction of human body with ASHRAE (American Society of Heating, Refrigerating and Air-conditioning) comfort chart in the loess interior space. In the view point of biomedical sciences, loess interior space provides optimum thermal conditions for human thermal sensation.

• Journal of applied mathematics & informatics
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• v.4 no.1
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• pp.211-222
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• 1997

In this paper we present a probabilistic approach for the estimation of realistic error bounds appearing in the execution of basic algebraic floating point operations. Experimental results are carried out for the extended product the extended sum the inner product of random normalised numbers the product of random normalised ma-trices and the solution of lower triangular systems The ordinary and probabilistic bounds are calculated for all the above processes and gen-erally in all the executed examples the probabilistic bounds are much more realistic.

• Journal of applied mathematics & informatics
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• v.19 no.1_2
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• pp.427-438
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• 2005

From a notion of d-pseudo-orthogonality for a sequence of poly-nomials ($d\;\in\;{2,3,\cdots}$), this paper introduces three different characterizations of natural exponential families (NEF's) with polynomial variance functions of exact degree 2d-1. These results provide extended versions of the Meixner (1934), Shanbhag (1972, 1979) and Feinsilver (1986) characterization results of quadratic NEF's based on classical orthogonal polynomials. Some news sets of polynomials with (2d-1)-term recurrence relation are then pointed out and we completely illustrate the cases associated to the families of positive stable distributions.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2005.10a
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• pp.266-271
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• 2005

In this study, following works have been carried out : division of Nakdong River Basin into 25 sub basins, development of a technique to evaluate spatial distribution of rainfall and analysis of rainfall data of 169 stations, selection of control points, and selection of a hydrologic model(SSARR). The runoff analysis showed that the surface-subsurface separation and soil moisture index parameters are the most important two to the simulation result.