• 한국산업융합학회 논문집
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• 제7권1호
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• pp.83-89
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• 2004

The analysis about consolidation characteristic in soft clay has been depending one-dimension consolidation analysis. but, drain and undrain zone are explicated as homogeneous by consolidation behavior following consoli- dated settlementsoft in soft clay. 1) Established sand drain in soft clay in many types, and measured water content, unconfined compression strength, vertical stress, horizontal stress, vertical settlement, pore water pressure. 2) Arranged the result from the test and numerically explicated effective stress, total stress, and effective stress path at the drain and undrain zone. 3) We also analyzed and comparied elastic and elastic-plastic in soft clay using measured data. The result analyzed does not approach to a special theory, but, it is well in accord with the result of other investigator's study in the same condition.

• 한국산업융합학회 논문집
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• 제19권2호
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• pp.69-74
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• 2016

This study proposes a new approach to design of the robust control application of a mobile manipulator with dual-arm. The mobil manipulator robot system consists of 12 DOF manipulators and a mobile robot. Kinematics of the robotics has been analyzed and simulated to verify reliability. A position-based torque control technique is applied to the robot by adding an outer loop to interact with the environment. Experimental studies of torque control applications of robot arm and interaction with a user operator are conducted. Experimental results has been proved that the robot arm performed regulated to follow the desired reference.

• 융합신호처리학회논문지
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• 제14권4호
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• pp.231-234
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• 2013

This paper introduces a mixture of background subtraction technique and K-Means clustering algorithm for removing shadows from video sequences. Lighting conditions cause an issue with segmentation. The proposed method can successfully eradicate artifacts associated with lighting changes such as highlight and reflection, and cast shadows of moving object from segmentation. In this paper, K-Means clustering algorithm is applied to the foreground, which is initially fragmented by background subtraction technique. The estimated shadow region is then superimposed on the background to eliminate the effects that cause redundancy in object detection. Simulation results depict that the proposed approach is capable of removing shadows and reflections from moving objects with an accuracy of more than 95% in every cases considered.

• 융합보안논문지
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• 제7권2호
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• pp.57-63
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• 2007

네트워크에서 데이터의 보안은 암호화에 의해 제공된다. 최근 영상이나 비디오와 같은 대용량의 데이터 파일의 암호화의 비용 및 복잡성을 줄이기 위한 방안으로 선택적 암호화가 제안되었다. 본 논문에서는 허프만 코딩으로 압축된 데이터의 암호화 방안을 제안하고 그 성능에 대해 논한다. 허프만 코드에 적용 가능한 단순한 선택적 암호화 방법을 제안하고 불안전한 채널에서 암호화 방법의 효율성에 대해 논의한다. 암호화 과정과 데이터 압축 과정이 하나로 결합될 수 있으며 그렇게 함으로서 데이터를 압축하고 암호화하는 과정을 간략화 하고 시간을 줄일 수 있다.

• ETRI Journal
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• 제26권2호
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• pp.185-188
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• 2004

In this paper, we design a two-step scheduling algorithm to support multiple bandwidth allocation policies for upstream channel access in an Ethernet passive optical network. The proposed scheduling algorithm allows us a simultaneous approach for multiple access control policies: static bandwidth allocation for guaranteed bandwidth service and dynamic bandwidth allocation for on-demand, dynamic traffic services. In order to reduce the scheduling complexity, we separate the process of the transmission start- time decision from the process of grant generation. This technique does not require the timing information of other bandwidth allocation modules, so respective modules are free from a heavy amount of timing information or complex processing.

• ETRI Journal
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• 제37권6호
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• pp.1251-1258
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• 2015

We investigate an image recovery method for sparse-view computed tomography (CT) using an iterative shrinkage algorithm based on a second-order approach. The two-step iterative shrinkage-thresholding (TwIST) algorithm including a total variation regularization technique is elucidated to be more robust than other first-order methods; it enables a perfect restoration of an original image even if given only a few projection views of a parallel-beam geometry. We find that the incoherency of a projection system matrix in CT geometry sufficiently satisfies the exact reconstruction principle even when the matrix itself has a large condition number. Image reconstruction from fan-beam CT can be well carried out, but the retrieval performance is very low when compared to a parallel-beam geometry. This is considered to be due to the matrix complexity of the projection geometry. We also evaluate the image retrieval performance of the TwIST algorithm -sing measured projection data.

• ETRI Journal
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• 제39권6호
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• pp.832-840
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• 2017

Recently, deep recurrent neural networks have achieved great success in various machine learning tasks, and have also been applied for sound event detection. The detection of temporally overlapping sound events in realistic environments is much more challenging than in monophonic detection problems. In this paper, we present an approach to improve the accuracy of polyphonic sound event detection in multichannel audio based on gated recurrent neural networks in combination with auditory spectral features. In the proposed method, human hearing perception-based spatial and spectral-domain noise-reduced harmonic features are extracted from multichannel audio and used as high-resolution spectral inputs to train gated recurrent neural networks. This provides a fast and stable convergence rate compared to long short-term memory recurrent neural networks. Our evaluation reveals that the proposed method outperforms the conventional approaches.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 D
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• pp.2283-2286
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• 2000

Sliding control is a powerful approach to controlling nonlinear and uncertain systems. Conventional sliding mode control suffer' from high control gain and chattering problem. also it needs mathematic! modeling equations for control systems. A Fuzzy controller is endowed with control rules and membership function that are constructed on the knowledge of expert, as like intuition and experience. but It is very difficult to obtain the exact values which are the membership function and consequent parameters. In this paper, without mathematical modeling equations, the plant parameters in sliding mode are estimated by the indirect adaptive fuzzy method. the proposed algorithm could analyze the system's stability and convergence behavior using Lyapunov theory. so sliding modes are reconstructed and decreased tracking error. moreover convergence time took a short. An example of inverted pendulum is given for demonstration of the robustness of proposed methodology.

• 융합보안논문지
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• 제8권2호
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• pp.7-13
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• 2008

국내외적으로 보안제품 평가를 위해서 공통평가기준(CC)을 제정하여 제품을 평가한다. 이와 같은 기준은 제품의 복잡성과 함께 버전이 변화되어 제품 평가의 기준을 확대하고 있다. 하지만 개발자 입장에서 제품을 설계할 때 보안성 평가 지침에 적합한 형태로 접근하기가 매우 어렵다는 문제점이 있다. 이는 개발자에게 제시되는 평가기준이 불명확하기 때문이다. 이에 본 연구에서는 개발자를 위한 합성제품 평가 지침을 제시함으로써 정보보안 제품을 설계단계에서부터 보안 제품 기준을 명확히 도입할 수 있도록 방안을 제시하고자 한다.

• ETRI Journal
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• 제31권2호
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• pp.225-227
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• 2009

A new planar metamaterial (MTM) with simultaneous negative values of permittivity (${\varepsilon}$) and permeability (${\mu}$) is proposed. Our MTM is composed of two identical copper patterns etched on both sides of dielectric laminate, which is very thin and easy to fabricate. Unlike conventional MTMs, the proposed structure shows a negative refractive index (NRI) behavior with respect to a normally incident wave. To explain the underlying principle of the NRI characteristics, an equivalent resonant circuit model based on surface current density distribution is investigated. An eigenmode analysis and a three-dimensional wave simulation for the stacked MTM prism are also performed to verify the existence of negative refraction. The experimental results from the transmission and reflection measurement ensure the validity of our design approach and show good agreement with the theoretically predicted effective medium parameters.