• Journal of Korea Society of Digital Industry and Information Management
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• v.5 no.2
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• pp.95-100
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• 2009

The Semantic Web is an evolving extension of the WWW in which the semantics of information and services on the web is defined, making it possible for the web to understand and satisfy the requests of people and machines to use the web content. The sementic web relied on the ontologies that structure underling data for the purpose of comprehensive and transportable machine understanding. The Semantic Web relies on the ontologies that structure underlying data for the purpose of comprehensive and transportable machine understanding. And recommendation systems have been developed as a solution to the abundance of choice people face in many situations. This paper shows that the new recommendation method is suitable for effective recommendation on the semantic web. We present a new procedure for improving the effective recommendation by using the levelized context ontology. Our experimental results also confirm that our method has good recommendation time. Our proposed method can be generalized to fit other application domains.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.10
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• pp.162-169
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• 2000

A Direct Drive Valve(DDV) hydraulic actuation system which is commonly used as an aircraft's control surface driving actuator has multi-loop control structure to ensure its safety operation. However, because of not perfect matching of one self channel characteristics with the others, the servo valve driving current of each channel can be widely different. Therefore, the long-time use of DDV actuator without any correction of these channel current offsets will cause the problem of performance or life expectancy degradation due to unwanted heats in the linear motor. A current equalization loop structure which can minimizes current offsets between channels is introduced and designed. The performance of the current equalization loop is investigated and verified through the analytic and experimental ways.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1435-1438
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• 2005

In hands-free telephone systems, the received speech signal is fed back to the microphone and constitutes the so-called echo. To cancel the effect of this time-varying echo path, it is necessary to device an adaptive filter between the receiving and the transmitting ends. For a typical FIR realization, the length of the fullband adaptive filter results in high computational complexity and low convergence rate. Consequently, subband adaptive filtering schemes have been proposed to improve the performance. In this work, we use deterministic approach to analyze the relationship between fullband and subband adaptive filtering structures. With block adaptive filtering structure as an intermediate stage, the analysis is divided into two parts. First, to avoid aliasing, it is found that the matrix of block adaptive filters is in the form of pseudocirculant, and the elements of this matrix are the polyphase components of the fullband adaptive filter. Second, to transmit the near-end voice signal faithfully, the analysis and the synthesis filter banks in the subband adaptive filtering structure must form a perfect reconstruction pair. Using polyphase representation, the relationship between the block and the subband adaptive filters is derived.

• International journal of advanced smart convergence
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• v.1 no.2
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• pp.43-46
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• 2012

We analyzed a periodic thick mushroom structure for use as an artificial magnetic conductor using mode-matching method. The fields in each region were represented by either Floquet modes or waveguide modes. By applying tangential electric and magnetic field continuity conditions and using matrix equations, unknown coefficients and dispersion diagram were calculated. The proposed model can account for the effects of oblique incidence. Simulation time using the method was much faster than the commercial tools. We found that the current method produces accurate results of reflection phase and dispersion diagram.

• Journal of Industrial Technology
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• v.35
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• pp.47-53
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• 2015

Recent extreme weather events and natural disasters are causing rapid aging of the ancient structures with cultural value. It has threatened the safety and management. The construction design documents are not kept for such long time. Even if they are, they seem to be mismatched with the design structures due to corrosive effects. For these reasons, Korea has been facing difficulties in maintenance, reengineering and safety evaluation. In this study, three dimensional point cloud surface of bobsleigh is obtained using 3D LiDAR scanner. The obtained structure is compared with the original design and found to be highly accurate. The study shows the application of reverse engineering technique and its potential use for other civil structures.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1997.04a
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• pp.169-175
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• 1997

Recently it is increased by degrees to produce complex and large lattice structures such as bridge, tower, crane, and space structures. In general, in order to analyse these structures we have used finite element method(FEM). In this method, however, it is necessary to use a large amount of computer memory and to take long computation time. For overcoming this problem, the Authors have developed the transfer dynamic stiffness coefficient method(TDSCM) which consists on the concept of the substructure synthesis method and transfer influence coefficient method. In this paper, the new free vibration analysis method for large type lattice structure is formulated by the TDSCM. And the results obtained by TDSCM are compared with those obtained by FEM, transfer matrix method and experiment. And it is confirmed for TDSCM to be the numerical high accuracy and high speed structure analysis method.

• Korean Journal of Computational Design and Engineering
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• v.12 no.3
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• pp.209-219
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• 2007

Designing a complex system such as an LCD developing system becomes inefficient when many designers are involved and create their own parts even though they can be used repeatedly in other sections. Thus, this paper proposes a new design process that can maximize the number of common parts in complex system design by organizing the 3D design process. The proposed design process consists of 5 stages: analysis of design intention, definition of initial product structure, definition of skeleton model, sharing design intention with all assembles, control of correlation between components. The proposed design process can maximize common parts in design process, which results in shorter lead time, less production cost, and greater economic benefits.

• 한국디지털정책학회:학술대회논문집
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• 2005.11a
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• pp.291-298
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• 2005

This paper is an analysis of the Category Individual Residence urban spatial structure along the National Route 20 (Koushu-Kaido), one of the major roads in Japan, and the degree of differences between locations and its changes between the points of time. The analysis was based on the GIS technique. Whilst, previous studies were based on municipal boundaries or mesh units as sources of data, GIS allowed the use of variable geographical units, Roadside zone, Inner zone, North zone, South zone, Blocks. As an example to apply the technology of GIS, 1986's sand 1991's building polygon data of the Urban Planning Bureau of Tokyo Metropolitan Government are used. The layers referred to the analyses is the building polygons with the amount of stories, building area, floor area and the material of the building. Two statistical analysis are executed; one is the test of the regional equality about the number of story of building, building area, floor area and fireproof building ratio.

• Communications for Statistical Applications and Methods
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• v.20 no.3
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• pp.235-240
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• 2013

Generalized linear mixed models(GLMMs) are frequently used for the analysis of longitudinal categorical data when the subject-specific effects is of interest. In GLMMs, the structure of the random effects covariance matrix is important for the estimation of fixed effects and to explain subject and time variations. The estimation of the matrix is not simple because of the high dimension and the positive definiteness; subsequently, we practically use the simple structure of the covariance matrix such as AR(1). However, this strong assumption can result in biased estimates of the fixed effects. In this paper, we introduce Bayesian modeling approaches for the random effects covariance matrix using a modified Cholesky decomposition. The modified Cholesky decomposition approach has been used to explain a heterogenous random effects covariance matrix and the subsequent estimated covariance matrix will be positive definite. We analyze metabolic syndrome data from a Korean Genomic Epidemiology Study using these methods.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.526-528
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• 1999

Epoxy resin has been used as matrix resin of advanced composites owing to ideally suitable properties and inherent physical and chemical properties for electrical and electronic insulation In this paper, in order to evaluate the performance of epoxy composites for out door insulation, variations of tracking resistance were investigated on the moisture absorption aging condition. Also, IPN methods were introduced in order to improve performance for out door use. As a result, it was confirmed that tracking resistance were degraded with boilling time. But, it was confirmed that specimen of IPN structure and KC-335 have the better tracking resistance properties than SIN structure by moisture absorption aging