• Structural Engineering and Mechanics
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• v.78 no.4
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• pp.485-496
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• 2021

So far analytical methods on collapse assessment of three-dimensional (3-D) steel frames have mainly focused on a single-column-removal scenario. However, the collapse of the Federal Building in the US due to car bomb explosion indicated that the loss of multiple columns may occur in the real structures, wherein the structures are more vulnerable to collapse. Meanwhile, the General Services Administration (GSA) in the US suggested that the removal of side columns of the structure has a great possibility to cause collapse. Therefore, this paper analytically deals with the robustness of 3-D steel frames in a two-side-column-removal (TSCR) scenario. Analytical method is first proposed to determine the collapse resistance of the frame during this column-removal procedure. The reliability of the analytical method is verified by the finite element results. Moreover, a design-based methodology is proposed to quickly assess the robustness of the frame due to a TSCR scenario. It is found the analytical method can reasonably predict the resistance-displacement relationship of the frame in the TSCR scenario, with an error generally less than 10%. The parametric numerical analyses suggest that the slab thickness mainly affects the plastic bearing capacity of the frame. The rebar diameter mainly affects the capacity of the frame at large displacement. However, the steel beam section height affects both the plastic and ultimate bearing capacity of the frame. A case study on a six-storey steel frame shows that the design-based methodology provides a conservative prediction on the robustness of the frame.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.05a
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• pp.155-158
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• 2008

In this paper, we propose a novel blind watermarking Method using 2D CAT (Two dimensional cellular automata transform). In our scheme, firstly, we obtain the gateway values to generate a dual-state, dual-coefficients basis function. Secondly, the basis function transforms images into cellular automata space. Lastly, we use the cellular automata transform coefficients to embed random noise watermark in the cover images. The proposed scheme allows only one 2D CAT basis function per gateway value. Since there are $2^{96}$ possible gateway values, better security is guaranteed. Moreover, the new method not only verifies higher fidelity than the existing method but also stronger stability on JPEG lossy compression, filtering, sharpening and noise through tests for robustness.

• The Transactions of the Korea Information Processing Society
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• v.1 no.2
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• pp.254-262
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• 1994

Most of traditional approaches to leader election have been based on a node ID number. As performances were not considered in these approaches, they were not very practical. So there has been a study on leader election strategies based on performances. This paper proposes new preference based on performances. While link failures occur during the election period, the elected leader's performance may not be the expected one. We simulate these effects of link failures on the robustness at election stragies. In particular, we tried in this study to find the best of the distributed election strategies based on the bidirectional preference from the standpoint of the robustness through simulation.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10a
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• pp.324-327
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• 1996

This paper describes the robust controller design methods applied to the problem of an automatic system for tow-vehicle/trailer combinations. This study followed an inverse Linear Quadratic Regulator(LQR) approach which combines pole assignment methods with conventional LOR methods. It overcomes two concerns associated with these separate methods. It overcomes the robustness problems associated with pole placement methods and trial and error required in the application of the LQR problem. Moreover, a Kalman filter is used as the observer, but is modified by using the loop transfer recovery (LTR) technique with modified transmission zero assignment. The proposed inverse LQG,/LTR controllers enhances the forward motion stability and maneuverability of the combination vehicles. At high speeds, where the inherent yaw damping of the vehicle system decreases, the controller operates to maintain an adequate level of yaw damping. At backward moton, both 4WS (2WS tow-vehicle, 2WS trailer) and 6WS (4WS tow-vehicle, 2WS trailer) control laws are proposed by using inverse LQG/LTR method. To evaluate the stability and robustness of the proposed controllers, simulations for both forward and backward motion were conducted using a detailed nonlinear model. The proposed controllers are significantly more robust than the previous controllers and continues to operate effectively in spite of parameter perturbations that would cause previous controllers to enters limit cycles or to loose stability.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.1
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• pp.99-108
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• 2010

RFID(Radio Frequency IDentification) is a technology that automatically identifies objects containing the electronic tags by using radio wave. When there are some tags in the domain of the RFID reader, the mechanism that can solve a collision between the tags occurs is necessary. The multi tag identification problem is the core issue in the RFID and could be resolved by the anti-collision algorithm. However, RFID system has another problem. The problem id user information security. Tag response easily by query of reader, so the system happened user privacy violent problem by tag information exposure. In the case, RFID system id weak from sniffing by outside. In this paper, We study of security robustness for tree-walking algorithm, query tree algorithm and advanced query tree algorithm of tree based memoryless algorithm.

• Nuclear Engineering and Technology
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• v.52 no.9
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• pp.2017-2024
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• 2020

In this study, a fractional order proportional integral derivative (FOPID) controller is designed to create the reference power trajectory and to conquer the uncertainties and external disturbances. A fractional nonlinear model was utilized to describe the nuclear reactor dynamic behaviour considering thermal-hydraulic effects. The controller parameters were tuned using optimization method in Matlab/Simulink. The FOPID controller was simulated using Matlab/Simulink and the controller performance was evaluated for Hard variation of the reference power and compared with that of integer order a proportional integral derivative (IOPID) controller by two models of fractional neutron point kinetic (FNPK) and classical neutron point kinetic (CNPK). Also, the FOPID controller robustness was appraised against the external disturbance and uncertainties. Simulation results showed that the FOPID controller has the faster response of the control attempt signal and the smaller tracking error with respect to the IOPID in tracking the reference power trajectory. In addition, the results demonstrated the ability of FOPID controller in disturbance rejection and exhibited the good robustness of controller against uncertainty.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.1
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• pp.323-343
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• 2020

With the rapid development of computer and communication techniques, copyright protection of vector geographic data has attracted considerable research attention because of the high cost of such data. A novel adaptive watermark detection algorithm is proposed for vector geographic data that can be used to qualitatively analyze the robustness of watermarks against data addition attacks. First, a watermark was embedded into the vertex coordinates based on coordinate mapping and quantization. Second, the adaptive watermark detection model, which is capable of calculating the detection threshold, false positive error (FPE) and false negative error (FNE), was established, and the characteristics of the adaptive watermark detection algorithm were analyzed. Finally, experiments were conducted on several real-world vector maps to show the usability and robustness of the proposed algorithm.

• Journal of information and communication convergence engineering
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• v.12 no.3
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• pp.173-180
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• 2014

This paper investigates the robustness of watermarking techniques for stereo or multi-view images generated from texture and depth images. A three-dimensional (3D) warping technique is applied to texture and depth images to generate stereo or multi-view images for a 3D display. By using the 3D warping technique, in this paper, we developed watermarking techniques and evaluated the robustness of these techniques that can extract watermarks from texture images even when the viewpoints are moved. A depth image is used to generate a stereo image with the largest viewpoint difference to the left and right. The overlapping region in the stereo image that does not disappear after warping is then obtained, and DWT is applied to this region to embed a watermark in the LL sub-band. The proposed watermarking techniques were found to yield bit error rates of about 3%-16% when they were applied to stereo images generated from texture and depth images. Furthermore, the results showed that the copyright could be seen when the extracted watermark was visually confirmed.

• Journal of Power Electronics
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• v.16 no.4
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• pp.1565-1577
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• 2016

For grid-connected LCL-filtered inverters, dual-loop current control with an inner-loop active damping (AD) based on capacitor current feedback is generally used for the sake of current quality. However, existing studies on capacitor current feedback AD with a control delay do not reveal the mathematical relation among the dual-loop stability, capacitor current feedback factor, delay time and LCL parameters. The robustness was not investigated through mathematical derivations. Thus, this paper aims to provide a systematic study of dual-loop current control in a digitally-controlled inverter. At first, the stable region of the inner-loop AD is derived. Then, the dual-loop stability and robustness are analyzed by mathematical derivations when the inner-loop AD is stable and unstable. Robust design principles for the inner-loop AD feedback factor and the outer-loop current controller are derived. Most importantly, ensuring the stability of the inner-loop AD is critical for achieving high robustness against a large grid impedance. Then, several improved approaches are proposed and synthesized. The limitations and benefits of all of the approaches are identified to help engineers apply capacitor current feedback AD in practice.

• Journal of Power Electronics
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• v.18 no.5
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• pp.1434-1447
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• 2018

The control design of inductive power transfer (IPT) systems has attracted a lot of attention in the field of wireless power transmission. Due to the high-order resonant networks and multiple loads in IPT systems, a simplified model of an IPT system is preferred for analysis and control design, and a controller with strong robustness is required. Hence, an active disturbance rejection control (ADRC) for IPT systems is proposed in this paper. To realize the employment of ADRC, firstly a small-signal model of an LC series-compensative IPT system is derived based on generalized state-space averaging (GSSA), then the ADRC is implemented in the designed IPT system. The ADRC not only provides superior robustness to unknown internal and external disturbances, but also requires few knowledge of the IPT system. Due to the convenient realization of ADRC, the designed IPT system retains its simple structure without any additional circuits. Finally, a frequency domain analysis and experimental results have validated the effectiveness of the employed ADRC, especially its robustness in the presence of frequency drifts and other common disturbances.