• Journal of KIISE:Software and Applications
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• v.26 no.4
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• pp.568-583
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• 1999

대량의 말뭉치(corpus)로부터 구문 정보나 의미 정보를 컴퓨터를 사용하여 자동으로 발췌하려는 연구가 활발하다. 그러나 실용적인 자연언어처리 시스템이 되기 위해 필요한 망라성(coverage)과 견고성(robustness)을 갖기 위해 어느 정도 규모의 말뭉치가 필요한지에 대한 연구는 극히 미비하다. 본 연구는 '우리말큰사전'상의 주요 4가지 품사에 속하는 단어들을 중심으로 상이 단어(different words) 수와 말뭉치 크기간의 상관관계를 통계적으로 고찰하여 수학적 예측함수(estimating functions)를 구한다. 그리고 이를 통해 자료 빈약성(data sparseness)현상을 타당한 수준으로 감소시켜 말뭉치를 기반 자연어처리의 신뢰도를 높이기 위해 요구되는 말뭉치 크기를 예측한다. 또한 예측된 말뭉치 크기를 근거로 합리적인 말뭉치 구축 방법을 제안한다.

• Journal of the Korean Society of Safety
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• v.21 no.1 s.73
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• pp.28-34
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• 2006

A procedure of estimating failure probability is demonstrated for a pressurized pipe of CrMo steel used at $538^{\circ}C$. Probabilistic fracture mechanics were employed considering variations of pressure loading, material properties and geometry. Probability density functions of major material variables were determined by statistical analyses of implemented data obtained by previous experiments. Distributions of the major variables were reflected in Monte Carlo simulation and failure probability as a function of operating time was determined. The creep crack growth life assessed by conventional deterministic approach was shown to be conservative compared with those obtained by probabilistic one. Sensitivity analysis for each input variable was also conducted to understand the most influencing variables to the residual life analysis. Internal pressure, creep crack growth coefficient and creep coefficient were more sensitive to failure probability than other variables.

• 한국지구물리탐사학회:학술대회논문집
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• 2007.06a
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• pp.197-202
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• 2007

Most of seismic reflection prospecting assumes subsurface formation to be homogeneous media. These models are not capable of estimating small scale heterogeneity which is verified by well log data or drilling core. And those synthetic seismograms by homogeneous media are limited to explain various changes at field data. So we developed a inhomogeneous velocity model which can estimate inhomogeneity of background medium to implement numerical modeling from homogeneous medium and inhomogeneous medium on the model. Background medium using three autocorrelation functions in order to generate inhomogeneous velocity media was according to dominant wavelength of background medium and correlation length of random medium. And then we compared shot gathers. The results show that numerical modeling implemented at inhomogeneous medium depicts complex wave propagation of field data.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2001.10a
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• pp.393-400
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• 2001

A simple numerical modelling technique is proposed for estimating the shear stress distribution in beams of framed tube structures with multiple internal tubes. The structures are analysed using a continuum approach in which each tube is individually modelled by a tube beam that accounts for the flexural and shear deformations, as well as the shear lag effects. The method idealises the discrete tubes-in-tube structures as an assemblage of equivalent multiple beams, each composed of orthotropic plate panels. The numerical analysis of shear stress is based on the elastic theory in conjunction with the minimum potential energy principle. By simplifying assumptions regarding the form of strain distributions in external and internal tubes, the shear stress distributions are expressed in terms of a series of linear functions of the second moments of area of the structures and the corresponding geometric and material properties, as well as the applied loads. The simplicity and accuracy of the proposed method are demonstrated through the solutions of three numerical examples.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.10b
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• pp.674-679
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• 1998

In designing the prestressed concrete box-bridge, the dead load, prestressing force, creep and shrinkage of concrete are the main factors which influence the camber and deflection of segmental concrete structure under construction. Among these factors the creep and shrinkage are the functions of the time-dependent property which, therefore, must be considered with time. The prediction model for estimating creep and shrinkage of concrete has been suggested by ACI, CEB/FIP, JSCE and KSCE design code and EMM, AEMM, RCM, IDM and SSM has been suggested for analytical method in consideration of the time-dependent characteristics. In this study, the creep test was carried out for four curing ages of concrete which were applied to the prestressed concrete structure at a construction site, and the results of test were compared to the values of creep prediction by the design code. Also the creep test of step-wise incremental stresses were performed and were compared to analytical methods.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.9 no.2
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• pp.76-82
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• 2009

A Heating, Ventilating and Air Conditioning (HVAC) system is a nonlinear multi-input multi-output (MIMO) system. This system is very difficult to control the temperature and the humidity ratio of a thermal space because of complex nonlinear characteristics. This paper proposes an adaptive fuzzy output feedback control based on observer for the nonlinear HVAC system. The nonlinear HVAC system is linearized through dynamic extension. State observers are designed for estimating state variables of the HVAC system. Fuzzy systems are employed to approximate uncertain nonlinear functions of the HVAC system with unavailable state variables. The obtained controller compares with an adaptive feedback controller. Simulation is given to demonstrate the effectiveness of our proposed adaptive fuzzy method.

• Journal of the Korea Institute of Building Construction
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• v.12 no.5
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• pp.528-538
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• 2012

With domestic construction projects becoming bigger, more specialized and more advanced, the construction industry is striving to improve quality and quantity, and is diversifying functions and shapes. Nevertheless, the process of a construction project causes problems when we estimate construction price, because the cost breakdown structures are different in each step. The primary aim of this study was to estimate building life cycle cost using the Delphi method. The cost breakdown structure for life cycle cost was classified into planning, design, construction, maintenance and waste disposal, and each detailed classification was determined by estimating life cycle cost. Moreover, the developed cost breakdown structure is verified by consulting with experts to secure objectivity and validity.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.1183-1188
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• 2004

The inverse heat conduction problem (IHCP) is a problem of estimating boundary condition from temperature measurement at one or more interior points. Neural networks are general information processing systems inspired by the connectionist theory of human brain. By properly training the network by the learning rule, the neural network method can handle many non-linear or other complex problems. In this work, neural network is applied to complicated inverse heat conduction problems. Efficiency of the procedure is enhanced by incorporating the radial basis functions (RBF). The RBF is trained faster than other neural network and can find smooth solution. In order to demonstrate the effectiveness of the current scheme, a typical one-dimensional IHCP is considered. At one surface, the temperature as well as the heat flux is known. The unknown temperature of interest is estimated on the other side of the slab. The results from the proposed method based on RBF neural network are compared with the conventional method.

• International Journal of Reliability and Applications
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• v.14 no.1
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• pp.27-39
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• 2013

In this article, a new model based on the Rayleigh distribution is introduced. This model is useful and practical in physics, reliability, and life testing. The statistical and reliability properties of this model are presented, including moments, the hazard rate, the reversed hazard rate, and mean residual life functions, among others. In addition, it is shown that the distributions of the new model are ordered regarding the strongest likelihood ratio ordering. Four estimating methods, namely, method of moment, maximum likelihood method, Bayes estimation, and uniformly minimum variance unbiased, are used to estimate the parameters of this model. Simulation is used to calculate the estimates and to study their properties. Finally, the appropriateness of this model for real data sets is shown by using the chi-square goodness of fit test and the Kolmogorov-Smirnov statistic.

• Proceedings of the IEEK Conference
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• 2000.07b
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• pp.707-710
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• 2000

WWW(World wide Web) is a place where many laymen receive and send the information at the worldwide. A visualization of WWW is very important as one of functions helping to retrieve and browse the information. However, as the information volume displayed at one time is limited by a screen size, it is useful to limit the volume of information capable for users to browse. In this report, we propose the page-index, which extract its information according to degree of user’s interest. This index is a numbers, which relate the user’s interest with verbal and structural characteristics of homepages. The homage-index constructed with sequence of this index are useful to help a user’s browsing. We constructed the estimating system about an article of commerce and really tried to estimate. From this trial, we verified the usefulness of the page-index, homepage-index.