• Proceedings of the KSRS Conference
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• v.1
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• pp.243-246
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• 2006

Wavelet approach is regarded as a useful methodology for geo-environment analysis with respect to spatial objects with periodicity and spatial pattern, compared to autocorrelation analysis, Fourier analysis, variogram analysis and so on. However, there are a few case studies for geo-lineament characterization with the actual geo-based information such as remotely sensed imagery and DEM. In this study, wavelet approach in the Uiseung caldera region are carried out to delineate characterization for geolineament spatial pattern. There are high possibilities of the development of radial lineaments from the centre of round crater due to the eruption of a volcano and the subsidence of a crater. We have grasped the directionality of the whole linear structures of the caldera via rose diagram, and then performed wavelet analysis on the profiles of orthogonal directions for main directions of the lineaments. The result of this study is likely to be used as a fundamental data in order to grasp the outline of caldera structure prior to the close estimation

• Transactions of the Korean Society of Mechanical Engineers
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• v.11 no.5
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• pp.856-866
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• 1987

In the present paper a statistical method using probability density function has been applied to investigate experimentally the flow patterns and fluctuations of time-averaged local void fraction in air-water two-phase mixtures which flow vertically upwards in concentric annuli. This study was carried out using three vertical concentric annuli. The annular test section consists of a lucite outer tube whose inside diameter is 38mm and a stainless steel inner rod. The rod diameter is either 12mm, 16mm or 20mm. The two-phase flow patterns observed in the experiment were bubbly, slug, annular and each transition patterns. It was first demonstrated that the variance, coefficients of skewness and kurtosis calculated from probability density function on time-averaged local void fraction can be used to identify the flow patterns in the annular passage, and the fluctuation of time-averaged local void fraction varies with the radial position in annular gap and the flow pattern.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.895-902
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• 2010

The method in a bid to make better use of limited urban space amidst increasingly expanding urban area have been attempted in various ways. Efficient using underground space is one of the examples. The pipe roof and excavation for underground crossing implemented in this study was the part of evaluation of such attempt. However, the pipe roof method for underground crossing may cause the ground surface to be uplifted or settled down, having effect on structure above the ground. Thus in this study, a laboratory model test designed to evaluate the effect on surface during implementing pipe roof and excavation was carried out. The ground displacement during pipe roof advancing and excavation is usually occurred in a radial shape but as the study focused on trackbed, the evaluation included ground settlement only. Thus, appropriately-scaled model was selected considering domestic geological characteristics and operation characteristics of traditional and high-speed rail trains and the qualitative evaluation of displacement was carried out with a certain ground loss depending on excavation after categorizing trackbed settlement pattern depending on depth of top soil.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1999.03b
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• pp.199-202
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• 1999

Many processing times for fabricating complex shaped parts by near net shape process such as thixoforming or semi-solid forming, are required due to the time for die design, induction heating and forming process. Therefore, for the thixoforming process, multi-capacity induction heating process is very important due to the reduction of the processing time and cost. It is indispensable to adopt a power-time heating pattern which manages to conciliate complete eutectic melting at the core with limited overheating at the periphery. The total reheating time is thus dependent on billet diameter; in inches$(pm20%)$. Typically, high frequency is used for the rapid reheating of the billet to the eutectic temperature range and low frequency for the remelting of the desired fraction of liquid and for the radial homogeneization of the liquid fraction. So in this study, the multi-capacity induction heating conditions of ALTHIX 86s alloy to reduce the processing time and cost would be proposed. The suitability of multi-capacity induction heating conditions would be verified through the comparison to Garat's data.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.7
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• pp.1064-1073
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• 2015

In this study, we introduce the pedestrian detection system by using the feature of HOG-PCA and RBFNNs pattern classifier. HOG(Histogram of Oriented Gradient) feature is extracted from input image to identify and recognize a object. And a dimension is reduced for improving performance as well as processing speed by using PCA which is a typical dimensional reduction algorithm. So, the feature of HOG-PCA through the dimensional reduction by using PCA leads to the improvement of the detection rate. FCM clustering algorithm is used instead of gaussian function to apply the characteristic of input data as well and connection weight is used by polynomial expression such as constant, linear, quadratic and modified quadratic. Finally, INRIA person database known as one of the benchmark dataset used for pedestrian detection is applied for the performance evaluation of the proposed classifier. The experimental result of the proposed classifier are compared with those studied by Dalal.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.21 no.4
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• pp.525-540
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• 1997

The effect of mold rotation on the transport process and resultant macrosegregation pattern during solidification of an Al-Cu alloy contained in a vertical axisymmetric annular mold cooled from the inner wall is numerically investigated. The mold initially at rest starts to rotate at a prescribed angular velocity simultaneously with the beginning of cooling. Computed results for a representative case show that the mold rotation essentially suppresses the development of both thermal and solutal convections in the melt, creating distinct characteristics such as the liquidus front, flow pattern and temperature distribution from those for the stationary mold. Thermal convection which develops at the early stages of cooling is soon extinguished by the rotating flow induced during spin-up, and thus does not effectively remove the initial superheat from the melt. On the other hand, solutal convection, though it weakens considerably and is confined within the mushy zone, still predominates over the solute redistribution process. With increasing the angular velocity, the solute transport in the axial direction is enhanced, whereas that in the radial direction is reduced. The final macrosegregation formed in the mold rotating at moderate angular velocities appears to be favorable in comparison with the stationary casting, in that not only relatively homogenized composition is achieved, but also a severely positive-segregated channel is restrained.

• Journal of Oral Medicine and Pain
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• v.17 no.2
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• pp.87-97
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• 1992

The purpose of this study is to investigate the age-and sex-related changes in the pH of resting saliva, viscosity, microorganisms and immunoglobulin A of stimulated whole saliva, and to investigate their correlations. The 120 healthy subjects were included in this study and the author used cone-and plate digital viscometer for viscosity, MSB agar for Streptococcus mutans, SL Rogosa agar for lactobacilli, and single radial immunodiffusion technique for immunoglobulinA. The obtained results were as follows : 1. There was no significant difference in pH, viscosity, Streptococcus mutans lactobacilli and immunoglobulin A of the saliva between males and females. 2. The viscosity values of stimulated whole saliva showed the increasing pattern with aging. 3. DMFS (or dmfs) rate was not correlated with pH, viscosity, Streptococcus mutans, lactobacilli and immunoglobulin A of the saliva. 4. There was a significant difference in the concentration of immunoglobulin A between the group under 10 and groups above 10. 5. The viscosity values of stimulated whole saliva showed the increasing pattern with decreasing of the number of Streptococcus mutans.

• Nuclear Engineering and Technology
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• v.48 no.5
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• pp.1126-1139
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• 2016

In this research, for the first time, a new optimization method, i.e., strength Pareto evolutionary algorithm II (SPEA-II), is developed for the burnable poison placement (BPP) optimization of a nuclear reactor core. In the BPP problem, an optimized placement map of fuel assemblies with burnable poison is searched for a given core loading pattern according to defined objectives. In this work, SPEA-II coupled with a nodal expansion code is used for solving the BPP problem of Kraftwerk Union AG (KWU) pressurized water reactor. Our optimization goal for the BPP is to achieve a greater multiplication factor ($K_{eff}$) for gaining possible longer operation cycles along with more flattening of fuel assembly relative power distribution, considering a safety constraint on the radial power peaking factor. For appraising the proposed methodology, the basic approach, i.e., SPEA, is also developed in order to compare obtained results. In general, results reveal the acceptance performance and high strength of SPEA, particularly its new version, i.e., SPEA-II, in achieving a semioptimized loading pattern for the BPP optimization of KWU pressurized water reactor.

• Nuclear Engineering and Technology
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• v.13 no.2
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• pp.63-72
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• 1981

The change in the design-basis refueling strategy caused by the unexpected nuclear fuel failures may result in discharging intact fuel assemblies which were irradiated in the positions symmetric to the failed ones in addition to the failed ones in order to maintain the symmetric power shape in the reactor core. In this work an attempt is made to reuse the intact fuel assemblies which were discharged before reaching the design turnup in the above-described situation so as to improve the fuel utilization. The TDCORE code is used to estimate the flux and power distribution, and the RELOAD-II code for searching the optimal loading pattern with the minimum assembly radial power peaking factor. For the case of the Ko-ri unit 1, its third cycle turnup could be extended to 11,648 MWD/MTU by reusing the four low-burned fuel assemblies removed at the end of the first cycle, and then the loading pattern is searched to the equilibrium cycle.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.5
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• pp.755-765
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• 2015

This paper is concerned with Interval Type-2 Radial Basis Function Neural Network classifier realized with the aid of Census Transform(CT) and (2D)2LDA methods. CT is considered to improve performance of face recognition in a variety of illumination variations. (2D)2LDA is applied to transform high dimensional image into low-dimensional image which is used as input data to the proposed pattern classifier. Receptive fields in hidden layer are formed as interval type-2 membership function. We use the coefficients of linear polynomial function as the connection weights of the proposed networks, and the coefficients and their ensuing spreads are learned through Conjugate Gradient Method(CGM). Moreover, the parameters such as fuzzification coefficient and the number of input variables are optimized by Artificial Bee Colony(ABC). In order to evaluate the performance of the proposed classifier, Yale B dataset which consists of images obtained under diverse state of illumination environment is applied. We show that the results of the proposed model have much more superb performance and robust characteristic than those reported in the previous studies.