• Journal of Institute of Control, Robotics and Systems
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• v.20 no.5
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• pp.526-532
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• 2014

In this paper, we present and analyze a LQ (Linear Quadratic) inverse optimal state-consensus protocol for continuous-time multi-agent systems with undirected graph topology. By Lyapunov analysis of the state-consensus error dynamics, we show the sufficient conditions on the algebraic connectivity of the graph to guarantee LQ inverse optimality and closed-loop stability. A more relaxed stability condition is also provided in terms of the algebraic connectivity. Finally, a formation control protocol for multiple mobile robots is proposed based on the target LQ inverse optimal consensus protocol, and the simulation results are provided to verify the performance of the proposed LQ inverse formation control method.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.15 no.6
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• pp.105-110
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• 2005

The linearized polynomial fan be regarded as a generalization of the identity function so that the inverse of the linearized polynomial is a generalization of e inverse function. Since the inverse function has so many good cryptographic properties, the inverse of the linearized polynomial is also a candidate of good Boolean functions. In particular, a construction method of vector resilient functions with high algebraic degree was proposed at Crypto 2001. But the analysis about the algebraic degree of the inverse of the linearized Polynomial. Hence we correct the inexact result and give the exact maximal algebraic degree.

• Communications for Statistical Applications and Methods
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• v.20 no.6
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• pp.455-466
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• 2013

In nested case-control studies, the most common way to make inference under a proportional hazards model is the conditional logistic approach of Thomas (1977). Inclusion probability methods are more efficient than the conditional logistic approach of Thomas; however, the epidemiology research community has not accepted the methods as a replacement of the Thomas' method. This paper promotes the inverse probability weighting method originally proposed by Samuelsen (1997) in combination with an approximate jackknife standard error that can be easily computed using existing software. Simulation studies demonstrate that this approach yields valid type 1 errors and greater powers than the conditional logistic approach in nested case-control designs across various sample sizes and magnitudes of the hazard ratios. A generalization of the method is also made to incorporate additional matching and the stratified Cox model. The proposed method is illustrated with data from a cohort of children with Wilm's tumor to study the association between histological signatures and relapses.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.7
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• pp.657-664
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• 2011

This study proposes an inverse method for estimating the boundary temperature in a gas-filled, onedimensional parallel domain enclosed by parallel plates. The distance between the plates is considered submicron to one mm. In the current method, it is assumed that the conditions of both heat flux and temperature are simultaneously applicable to one boundary, while no conditions are applicable to the other boundary The temperature on one of the boundaries should be inversely determined from the known temperature and heat flux on the other boundary. This study proposes a procedure for estimating the unknown boundary temperature through Monte Carlo simulation. Both the forward and inverse problems employ the Monte Carlo approach. The forward (direct) problem is solved by using the direct simulation Monte Carlo while the inverse solution is obtained by the simulated annealing.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.12 no.6
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• pp.554-560
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• 2019

In this study, after applying the finite failure NHPP Rayleigh distribution model and NHPP Inverse Rayleigh distribution model which are widely used in the field of software reliability to the software development cost model, the attributes of development cost and optimal release time were compared and analyzed. To analyze the attributes of software development cost, software failure time data was used, parametric estimation was applied to the maximum likelihood estimation method, and nonlinear equations were calculated using the bisection method. As a result, it was confirmed that Rayleigh model is relatively superior to Inverse Rayleigh model because software development cost is relatively low and software release time is also fast. Through this study, the development cost attributes of the Rayleigh model and the Inverse Rayleigh model without the existing research examples were newly analyzed. In addition, we expect that software developers will be able to use this study as a basic guideline for exploring software reliability improvement method and development cost attributes.

• Steel and Composite Structures
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• v.18 no.4
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• pp.889-907
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• 2015

This paper aims to present an alternative analytical method for transient vibration analysis of doubly-curved laminated shells subjected to dynamic loads. In the method proposed, the governing differential equations of laminated shell are derived using the dynamic version of the principle of virtual displacements. The governing equations of first order shear deformation laminated shell are obtained by Navier solution procedure. Time-dependent equations are transformed to the Laplace domain and then Laplace parameter dependent equations are solved numerically. The results obtained in the Laplace domain are transformed to the time domain with the help of modified Durbin's numerical inverse Laplace transform method. Verification of the presented method is carried out by comparing the results with those obtained by Newmark method and ANSYS finite element software. Also effects of number of laminates, different material properties and shell geometries are discussed. The numerical results have proved that the presented procedure is a highly accurate and efficient solution method.

• Journal of Mechanical Science and Technology
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• v.15 no.2
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• pp.232-238
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• 2001

Fast Fourier Transformation is employed to convert the head variation of a pipeline in the time domain to the amplitude of the frequency domain. Applying method of characteristics to a pipeline provides a significant frequency range for a surge introduced from the valve modulation. Inverse Fast Fourier Transformation and a Finite Impulse Response Filter can be used to remove any possible noise existing from the significant frequency range of an unsteady condition. A filtered signal shows higher potential for the inverse calculation of leakage detection than the noise-added signal does. The respective performances of Inverse Fast Fourier Transformation and a Finite Impulse Response Filter are compared in terms of leakage detection capability. Characteristics of the frequency range for multiple leakages were investigated to validate the effectiveness of the noise control method in the frequency domain.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.11
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• pp.1064-1069
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• 2015

Control Moment Gyro (CMG) has been used as an indirect actuator of a single-wheel robot system GYROBO, developed at Chungnam National University. The flip motion of the gimbal system produces the gyroscopic motion onto the body system while the body motion also produces the gyroscopic motion onto the gimbal system inversely. In this paper, the intuitive equation of the inverse gyroscopic effect is derived as the direct relation between the rate of the body system and the rate of the gimbal system. Experiments on the inverse gyroscopic effect under the chaotically generated disturbance are conducted. Experimental data are approximated by a linear equation using the least square method.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.6
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• pp.561-567
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• 2011

The inverse radiation analysis of a two-dimensional irregular configuration using unstructured triangular meshes is presented. In this study, an enclosure filled with an absorbing, emitting and scattering medium with diffusely emitting and reflecting opaque boundaries is considered. The finite volume method is applied to solve the radiative transfer equation in order to simulate the measured incident radiation values which are used as input data for the inverse analysis. The conjugate gradient method is adopted for the estimation of wall emissivities by minimizing the objective function at each iteration step. To verify the performance of the unstructured grid system, we compare the results with those using a structured grid system for the two-dimensional lopsided shape. The effect of measurement errors on the estimation accuracy is also investigated.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2002.03a
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• pp.125-132
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• 2002

In this study, a numerical method is developed for nonlinear analysis for soil-pile-structure interaction system in time domain. Finite elements considering material nonlinearity are used for the near field and boundary elements for the far field. In the near field, frame elements are used for modeling a pile and plane-strain elements for surrounding soil and superstructure. In. the far field, boundary element formulation using the dynamic fundamental solution is adopted and coupled with the near field. Transformation of stiffness matrices of boundary elements into time domain is performed by inverse FFT. Stiffness matrices in the near field and far field are coupled. Newmark direct time integration method is applied. Developed soil-pile-structure interaction analysis method is verified with available literature and commercial code. Also, parametric studies by developed numerical method are performed. And seismic response analysis is performed using actual earthquake records.