• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.54.6-54
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• 2002

1. Introduction 2. The Netwoked Control System Description 2.1 A close-loop system with the network induced delay 2.2 Discretization and State Augmentation of NCS 3. Delay-dependent H_infinity Controller Design for NCS 4. Numerical Example 5. Conclusion

• The Journal of Korea Robotics Society
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• v.11 no.4
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• pp.277-284
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• 2016

A new prediction scheme has been proposed for the robust teleoperation in a non-visible environment. The positioning error caused by the time delay in the non-visible environment has been compensated for by the Smith predictor and the sensory data have been estimated by the Grey model. The Smith predictor is effective for the compensation of the positioning error caused by the time delay with a precise system model. Therefore the dynamic model of a mobile robot has been used in this research. To minimize the unstable and erroneous states caused by the time delay, the estimated sensor data have been sent to the operator. Through simulations, the possibility of compensating the errors caused by the time delay has been verified using the Smith predictor. Also the estimation reliability of the measurement data has been demonstrated. Robust teleoperations in a non-visible environment have been performed with a mobile robot to avoid the obstacles effective to go to the target position by the proposed prediction scheme which combines the Smith predictor and the Grey model. Even though the human operator is involved in the teleoperation loop, the compensation effects have been clearly demonstrated.

• The Korean Journal of Air & Space Law and Policy
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• v.32 no.2
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• pp.3-31
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• 2017

On 12 October 2017, the English Royal Courts of Justice delivered its decision about air carrier's compensation liability for the flight delay. In the cases the passengers suffered delays at a connecting point and, consequently, on arrival at their final destination. They claimed compensation under Regulation 261/2004 (the "Regulation"), as applied by the Court of Justice of the European Union (the "CJEU") in Sturgeon v. Condor [2009]. The principal issues were whether delays suffered by the passengers during the second leg of their respective journeys were compensable under the Regulation, whether there was jurisdiction under the Regulation and whether the right to compensation under the Regulation is, insofar as non-Community air carriers are concerned, excluded by virtue of the exclusive liability regime established under the Montreal Convention 1999. The passengers, the plaintiff, argued that the relevant delay was not that on flight 1 but that suffered at the "final destination". They maintained that there was no exercise by the EU of extraterritorial jurisdiction as the delay on flight 2 was merely relevant to the calculation of the amount of compensation due under the Regulation. The air carrier, the defendant, however argued that the only relevant flights for the purpose of calculating any delay were the first flights (flights 1) out of EU airspace, as only these flights fell within the scope of the Regulation; the connecting flights (flights 2) were not relevant since they were performed entirely outside of the EU by a non-Community carrier. Regarding the issue of what counts as a delay under the Regulation, the CJEU held previously on another precedents that the operating carrier's liability to pay compensation depends on the passenger's delay in arriving at the "final destination". It held that where the air carrier provides a passenger with more than one directly connecting flight to enable him to arrive at their destination, the flights should be taken together for the purpose of assessing whether there has been three hours' or more delay on arrival; and that in case of directly connecting flights, the final destination is the place at which the passenger is scheduled to arrive at the end of the last component flight. In addition, the Court confirmed that the Regulation applied to flights operated by non-Community carriers out of EU airspace even if flight 1 or flight 2 lands outside the EU, since the Regulation does not require that a flight must land in the EU. Accordingly, the passengers' appeal from the lower Court was allowed, while that of air carrier was dismissed. The Court has come down firmly on the side of the passengers in this legal debate. However, this result is not a great surprise considering the recent trends of EU member states' court decisions in the fields of air transport and consumer protection. The main goal of this article is to review the Court's decision and to search historical trend of air consumer protection especially in EU area.

• The Transactions of the Korean Institute of Power Electronics
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• v.9 no.3
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• pp.275-284
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• 2004

This paper discusses how to control the compensation voltages in dynamic voltage restorers (DVR). On analyzing the power circuit of a DVR system, control limitations and control targets are presented for the voltage compensation in DVRs. Based on the preceded power stage analysis, a novel controller for the compensation voltages of DVRs is proposed by a feed forward control scheme. This paper discusses also the time delay problems in the control system of DVRs. Digitally controlled DVR systems normally have control delay at amount of one sampling time of the control system and a half of the switching period of the DVR inverter. The control delay in digital controllers increases the dimension of the system transfer function one degree higher, which makes the control system more complicate and more unstable. This paper proposes a guide line to design the control gain, appropriate output filter parameters and inverter switching frequency for DVRs with digital controllers. Proposed theory is verified by an experimental DVR system with a full digital controller.

• Journal of Advanced Marine Engineering and Technology
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• v.41 no.1
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• pp.105-110
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• 2017

This paper introduces a heave compensation system for offshore crane when it subjected to unexpected disturbances such as ocean waves, tidal currents or winds and their external force. The dynamic model consists of a crane which is considered to behave in the same manner as a rigid body, a hydraulic driven winch, an elastic rope and a payload. To keep the payload from moving upwards and downwards, PD(Proportional-Derivative) control was applied by using linearization. In order to achieve a better performance, the sliding mode control and the nonlinear generalized predictive control algorithm was applied according to the time-delay. As a result, the oscillating amplitude of the payload was reduced by the control algorithm. Considering the time-delay involved in the system to be one second, nonlinear generalized predictive controller with a robust controller was a suitable control algorithm for this heave compensation system because it made the position of te payload reach the desired position with the minimum error. This paper presented a control algorithm using the robust control and its simulation results.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.12
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• pp.1742-1747
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• 2015

An improved transfer alignment method for a strap-down inertial navigation system (SDINS) is presented here. The alignment accuracy in conventional method is vulnerable to the data latency of a Master INS (MINS) in high maneuverable platforms. We propose a time delay compensation equation considering higher-order terms in the attitude measurement equation of the Kalman filter. The equation incorporates additional information including angular rate, angular acceleration and linear acceleration from the MINS. Simulation results show that the transfer alignment accuracy is significantly improved in the high dynamic environment by incorporating the latency compensation technique.

• JSTS:Journal of Semiconductor Technology and Science
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• v.8 no.3
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• pp.179-192
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• 2008

A multiphase compensation method with mismatch linearization technique, is presented and demonstrated in a $\Sigma-\Delta$ fractional-N frequency synthesizer. An on-chip delay-locked loop (DLL) and a proposed delay line structure are constructed to provide multiphase compensation on $\Sigma-\Delta$ quantizetion noise. In the delay line structure, dynamic element matching (DEM) techniques are employed for mismatch linearization. The proposed $\Sigma-\Delta$ fractional-N frequency synthesizer is fabricated in a $0.18-{\mu}m$ CMOS technology with 2.14-GHz output frequency and 4-Hz resolution. The die size is 0.92 mm$\times$1.15 mm, and it consumes 27.2 mW. In-band phase noise of -82 dBc/Hz at 10 kHz offset and out-of-band phase noise of -103 dBc/Hz at 1 MHz offset are measured with a loop bandwidth of 200 kHz. The settling time is shorter than $25{\mu}s$.

• Journal of Information Processing Systems
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• v.13 no.4
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• pp.677-688
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• 2017

In order to solve the undetected probability of multiple targets in ultra-wideband (UWB) through-the-wall radar imaging (TWRI), a time-delay and amplitude modified back projection (BP) algorithm is proposed. The refraction point is found by Fermat's principle in the presence of a wall, and the time-delay is correctly compensated. On this basis, transmission loss of the electromagnetic wave, the absorption loss of the refraction wave, and the diffusion loss of the spherical wave are analyzed in detail. Amplitude compensation is deduced and tested on a model with a single-layer wall. The simulating results by finite difference time domain (FDTD) show that it is effective in increasing the scattering intensity of the targets behind the wall. Compensation for the diffusion loss in the spherical wave also plays a main role. Additionally, the two-layer wall model is simulated. Then, the calculating time and the imaging quality are compared between a single-layer wall model and a two-layer wall model. The results illustrate the performance of the time-delay and amplitude-modified BP algorithm with multiple targets and multiple-layer walls of UWB TWRI.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.1
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• pp.42-49
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• 2016

In this paper, we design and fabricate an instantaneous frequency measurement receiver with a frequency resolution of 125 MHz which detects and measures continuous signals in 4~6 GHz using path difference of delay lines. The receiver has a 4-bit configuration and consists of power dividers, delay lines, power combiners, power detectors, voltage comparator circuits and so on. The accuracy of the instantaneous frequency measurement is improved by applying offset voltage compensation to the comparator circuits to compensate the frequency-dependent path loss of the delay line and the frequency dependence of power detection.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.1
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• pp.56-63
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• 2008

This paper describes a 12 bit 1GS/s current mode segmented DAC for WCDMA communication. The proposed circuit in this paper employes segmented structure which consists of 4bit binary weighted structure in the LSB and 4bit thermometer decoder structure in the mSB and MSB. The proposed DAC uses delay time compensation circuits in order to suppress performance decline by delay time in segmented structure. The delay time compensation circuit comprises of phase frequency detector, charge pump, and control circuits, so that suppress delay time by binary weighted structure and thermometer decoder structure. The proposed DAC uses CMOS $0.18{\mu}m$ 1-poly 6-metal n-well process, and measured INL/DNL are below ${\pm}0.93LSB/{\pm}0.62LSB$. SFDR is approximately 60dB and SNDR is 51dB at 1MHz input frequency. Single DAC's power consumption is 46.2mW.