• Journal of Korean Association for Spatial Structures
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• v.3 no.3 s.9
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• pp.75-83
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• 2003

The purpose of this study is to obtain the optimum shape of cable domes by using the real coding genetic algorithm. Generally, the structural performance of the cable domes is influenced very sensitively by pre-stress, geometry and length of the mast because of flexible system. So, it is very important to decide the optimum shape to get maximum stiffness of cable domes. We use the analytical model to verify the usefulness of this algorithm for shape optimization and analyze the roof system of Seoul olympic gymnastic arena as analytical model of a practical structures. It is confirmed lastly that the optimum shape domes have more stiffness than initial shape ones.

• Korean Journal of Computational Design and Engineering
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• v.11 no.6
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• pp.429-439
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• 2006

The purpose of this study is to support the integration from current 2D drawing-based design to future 3D model-based design. In this paper, an important theme is the combination between the STEP-based 2D drawing standards (i.e., AP202) and the IFC-based 3D building model standards. To achieve the purpose, two methodologies are proposed as follows: the development of IFC extension model for the 2D shape data representation by harmonizing ISO/STEP AP202; and the development of mapping solution between IFC 2D extension model and KOSDIC by constructing the exchange scenario for 2D shape data representation. It is expected that the proposed IFC2X2 2D extension model and mapping solution will offer the basis of development of the integrated standards model in AEC industry.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.9 no.6
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• pp.566-572
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• 2016

Software Reliability implemented in software development is one of the most important issues. In finite failure NHPP software reliability models for software failure analysis, the hazard function that means a failure rate may have constant independently for failure time, non-increasing or non-decreasing pattern. In this study, software development cost analysis considering the variable shape parameter of Erlang distribution as the failure life distribution in the software product testing process was studied. The software failure model was applied finite failure Non-Homogeneous Poisson Procedure and the parameters approximation using maximum likelihood estimation was accompanied. Thus, this paper was presented comparative analysis by applying a software failure time data to the software, considering the shape parameter of Erlang distribution for development cost model analysis. When compared to the cost curve in accordance with the shape parameter, the model of smaller shape can be seen that the optimal software release time delay and more cost. Through this study, it is thought that it can serve as a preliminary information which can basically help the software developers to search for development cost according to software shape parameters.

• Journal of Biomedical Engineering Research
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• v.21 no.4
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• pp.411-417
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• 2000

This paper describes the analysis of the oscillometric method based on the shape of arterial pressure and proposal of a new algorithm for estimating the blood pressure by computer simulation. In the first step, the arterial pressure model which is able to control the shape of arterial pressure was designed and then we simulated the oscillometric model using both the existing exponential model showing the static arterial pressure-volume relation and the designed arterial pressure model. By analyzing the correlation of characteristic ratio based on the shape of arterial pressure, we could find that the characteristic ratio was not the only standard parameter for estimating systolic and diastolic pressure. We were able to estimate the shape of arterial pressure by computing the correlation of arterial pressure shape with oscillation shape. Finally, we proposed an algorithm which is able to estimate systolic and diastolic pressure according to pressure(Pp) table constructed from the relation of maximum amplitude of oscillation and arterial pressure shape. We tested 60 arterial pressure waveforms having various arterial pressure shape and pulse. As a results, the absolute deviation average values of the estimation of systolic, diastolic and mean pressure were 1.62%, 2.40% and 2.20%, respectively. In conclusions, the proposed algorithm showed the possibility of usefullness in estimating the blood pressure.

• Journal of Korea Multimedia Society
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• v.17 no.12
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• pp.1412-1417
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• 2014

The corpus callosum is the largest part of the brain, which is related to many neurological diseases. Snake model or active contour model is widely used in medical image processing field, especially image segmentation they look into the nearby edge, localizing them accurately. In this paper, corpus callosum segmentation using the snake model, is proposed. We tested a snake model on brain MRI. Then we compared the result with an active shape approach and found that snake model had better segmentation accuracy also faster than active shape approach.

• Smart Structures and Systems
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• v.16 no.4
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• pp.641-665
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• 2015

In this paper, a simple and efficient phenomenological macroscopic one-dimensional model is proposed which is able to simulate main features of shape memory alloys (SMAs) particularly ferro-elasticity effect. The constitutive model is developed within the framework of thermodynamics of irreversible processes to simulate the one-dimensional behavior of SMAs under uniaxial simple tension-compression as well as pure torsion+/- loadings. Various functions including linear, cosine and exponential functions are introduced in a unified framework for the martensite transformation kinetics and an analytical description of constitutive equations is presented. The presented model can be used to reproduce primary aspects of SMAs including transformation/orientation of martensite phase, shape memory effect, pseudo-elasticity and in particular ferro-elasticity. Experimental results available in the open literature for uniaxial tension, torsion and bending tests are simulated to validate the present SMA model in capturing the main mechanical characteristics. Due to simplicity and accuracy, it is expected the present SMA model will be instrumental toward an accurate analysis of SMA components in various engineering structures particularly when the ferro-elasticity is obvious.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2006.11a
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• pp.173-179
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• 2006

In order to explain a U-shape pattern of stock returns, Fama and French(1988) suggested the state-space model consisting of I(1) permanent component and AR(1) stationary component. They concluded the autoregression coefficient induced from the state-space model follow the U-shape pattern and the U-shape pattern of stock returns was due to both negative autocorrelation in returns beyond a year and substantial mean-reversion in stock market prices. However, we found negative autocorrelation is induced under the assumption that permanent and stationary noise component are independent in the state-space model. In this paper, we derive the autoregression coefficient based on ARIMA process equivalent to the state-space model without the assumption of independency. Based on the estimated parameters, we investigate the pattern of the time-varying autoregression coefficient and conclude the autoregression coefficient from the state-space model of ARIMA(1,1,1) process does not follow a U-shape pattern, but has always positive sign. We applied this result on the data of 1 month retums for all NYSE stocks for the 1926-85 period from the Center for Research in Security Prices.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.3
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• pp.381-386
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• 2003

Gradually engineering designers are determined based on computer simulations. Modeling of the computer simulation however is too expensive and time consuming in a complicate system. Thus, designers often use approximation models called metamodels, which represent approximately the relations between design and response variables. There arc general metamodels such as response surface model and kriging metamodel. Response surface model is easy to obtain and provides explicit function. but it is not suitable for highly nonlinear and large scaled problems. For complicate case, we may use kriging model that employs an interpolation scheme developed in the fields of spatial statistics and geostatistics. This class of into interpolating model has flexibility to model response data with multiple local extreme. In this study. metamodeling techniques are adopted to carry out the shape optimization of a funnel of Cathode Ray Tube. which finds the shape minimizing the local maximum principal stress Optimum designs using two metamodels are compared and proper metamodel is recommended based on this research.

• Fisheries and Aquatic Sciences
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• v.3 no.2
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• pp.156-162
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• 2000

Model experiments for a purse seine were carried out in order to measure the geometry of net shape and to estimate an enclosed volume by using 1177 scale model purse seine of 12.62m float line from an offshore mackerel purse seine. A model purse seine was set from a net box of shooting equipments and then pursing and hauling net by hauling equipment. The 3- D geometry shape of the purse seine net during hauling operation was measured by video image processing and tension of purse line by load cell. The 3-D geometry of the model purse seine during hauling operation could be represented with variables such as a ratio of shooting diameter or maximum net depth and a ratio of hauling operation time. Horizontal shapes of float line and lead line were varied from a circle after shooting to an ellipse with pursing and hauling. Projected lateral shape of purse line was observed and formulated as a shape of a water drop. The cross sectional shapes of curved net from two directions were varied such as sine function or polynomial curves. Therefore, enclosed volume of a purse seine in relation to fish school behaviour can be approximated using two main variables from relevant equations.

• Journal of Korean Institute of Industrial Engineers
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• v.28 no.3
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• pp.274-282
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• 2002

This paper discusses a multi-dimensional analysis for Customer Relationship Management (CRM). For this, We propose a decision-making methodology which employs three analysis models. The first model is a three-dimension positioning map to derive a strategy which achieves the Process Value Line (PVL). The second model is the web-shape analysis model to visibly understand the individual based on the customer CSI (Customer Satisfactory Index) data. The third model which supports the web-shape analysis model, is the relative satisfactory analysis model. It considers a satisfaction level after purchasing against before purchasing. Then we perform overall analysis based on the three analysis models to provide marketing strategies to decision makers.