Loss Compensation Scheme Research Articles

A Novel Aperture Extension Loss Compensation Scheme and Azimuth Ambiguity Suppression Method for Airborne Elevation DBF-SAR

Digital beamforming (DBF) is a state-of-the-art technique for high-resolution and wide-swath (HRWS) observation in synthetic aperture radar (SAR) imaging. Since azimuth high-resolution imaging will be a popular tendency in future SARs, DBF-SAR needs to become practical. A new problem arising in airborne DBF-SAR application is the aperture extension loss (AEL). Similar to the pulse extension loss, it is confirmed in our study that AEL will widen the point target responses and degrade the signal-to-noise ratio (SNR) improvement in airborne DBF-SAR. However, little work has been devoted to the compensation of the AEL effect. In this article, the effects of AEL are demonstrated and two compensation methods are proposed, discussed, and implemented for the processing of raw data. The above are demonstrated through simulations and an airborne experimental C-band azimuth high-resolution DBF-SAR. The results show that the AEL compensation removes the AEL effects and increases the SNR with the cost of higher impulse response sidelobes. Moreover, with this novel design scheme, it is demonstrated that azimuth ambiguity suppression can be implemented by elevation DBF.

Analysis of Tax Management Through Corporate Loss Compensation Scheme

Analysis of Tax Management Through Corporate Loss Compensation Scheme

군용비행장 소음소송의 실체법 및 소송법상 쟁점에 관한 검토

On April 11, 2001, as the first ruling to admit the national liability for damages to residents living near the Maehyang-ri shooting range was rendered, the litigations to claim damages caused by noise has been rapidly increased. In particular, recently, the lawsuits tended to be grouped, and in the case of noise lawsuits related to K2 Air Force Base in Dong-gu, Daegu, which was first filed in 2001 and concluded by the Supreme Court in 2011, ten years later, more than 150,000 plaintiffs were participated. This noise litigation is not only socially expensive due to the government"s financial burden, the possibility of new disputes over contingency fees with lawyers, and repeated claims for damages every three years.<BR> The enactment of the Military Noise Compensation Act and the establishment of a loss compensation system, like civil airports, is encouraging in that it prevents the inefficiency of resolving noise disputes through the payment of compensation for emotional distress. However, regardless of the establishment of the loss compensation scheme, because claims for damages are still available, noise litigations may continue in some cases. And as the first compensation under the Military Noise Compensation Act will be initiated only after 2022, many unresolved cases are and will be pending in courts. In particular, in the case of administrative loss compensation and civil damage compensation, there should be no significant difference in the total amount of compensation, so that additional disputes can be prevented. Since it is necessary to refer to the law of the substance law and the law of litigation law even after the ｢Noise Compensation Act｣, it is still necessary to study them.<BR> In this context, if we look at the substantive laws, we can figure out our courts have established a theory of strict liability for damages caused by defects in the installation and management of the objects, so that the victims of noise lawsuits only need to prove that the degree of damage they have suffered exceeds the acceptance limit, other than proving the state"s will or negligence or physical and external defects of the objects. Our court provides several factors to consider when setting the limit, but there is a problem that it is oversimplified or uniformly set. In addition, it is considered that the problem of repeatedly filing a lawsuit every three years is to be resolved by allowing a action for future performance in the form of periodic payments, and subsequent changes to circumstances must be resolved through a claim for Modification of Judgment for Periodic Payment.

Hyperbolic Metamaterial as a Tunable Near-Field Spatial Filter to Implement Active Plasmon-Injection Loss Compensation

We present how to physically realize the auxiliary source described in the recently introduced active plasmon injection loss compensation scheme for enhanced near-field superlensing. Particularly, we show that the characteristics of the auxiliary source described in the active plasmon injection scheme including tunable narrow-band and selective amplification via convolution can be realized by using a hyperbolic metamaterial functioning as a near-field spatial filter. Besides loss compensation, the proposed near-field spatial filter can be useful for real-time high resolution edge detection.

Active plasmon injection scheme for subdiffraction imaging with imperfect negative index flat lens

We present an active physical implementation of the recently introduced plasmon injection loss compensation scheme for Pendry's non-ideal negative index flat lens in the presence of realistic material losses and signal-dependent noise. In this active implementation, we propose to use a physically convolved external auxiliary source for signal amplification and suppression of the noise in the imaging system. In comparison with the previous passive implementations of the plasmon injection scheme for sub-diffraction limited imaging, where an inverse filter post-processing is used, the active implementation proposed here allows for deeper subwavelength imaging far beyond the passive post-processing scheme by extending the loss compensation to even higher spatial frequencies.

Analytical description of inverse filter emulating the plasmon injection loss compensation scheme and implementation for ultrahigh-resolution hyperlens

An inverse filter full analytical description and implementation of a recently proposed plasmon injection scheme for improving the resolution of a hyperlens is presented. Different types of loss mechanisms existing in the hyperlens imaging system are identified and studied in detail. It is shown that the plasmon injection scheme and its inverse filter analog can compensate all the major loss mechanisms. As a result, an object with deep subwavelength features, otherwise unresolvable with a hyperlens alone, is fully reconstructed.

Design of Feed Control System for Micro EDM Machine Tool

This paper designs the closed-loop feedback control system of MEDM, which is based on the motion control card and data acquisition card. To ensure the accuracy of the process, the gap can be regulated through the analysis of discharge condition and the analysis and treatment of the gap voltage, and then a servo control scheme on small holes machining is presented. Through this way, the electrode loss compensation scheme can be solved, which can improve the efficiency and practicality of MEDM.

Research on Matrix-type Packet Loss Compensation Scheme for Wireless Video Transmission on Subway

As the mainstream wireless LAN technology, Wi-Fi can achieve fast data transfer. With the subway moving in a high speed, video data transmission between the metro and the ground is achieved through Wi-Fi technology. This paper aims at solving the Caton problem caused by switching packet loss in the process of playing real-time video on the train terminal, and proposes matrix-type packet loss compensation scheme. Finally, the feasibility of the scheme is verified by experiments.

Design of High- $Q$ Compact Passive Ring Resonators via Incorporating a Loss-Compensated Structure for High Performance Angular Velocity Sensing in Monolithic Integrated-Optical-Gyroscopes

A compact InP/InGaAsP passive ring resonator (PRR), in which a loss-compensation section is vertically integrated, for angular velocity sensing is theoretically studied in this paper. The loss compensation is realized by current injection into the optical gain section, which is optically coupled with the PRR. Based on the proposed loss-compensation scheme, the propagation loss in the PRR can be reduced down to 0.01 dB/cm. Consequently, the quality factor of up to $1.5 \times 10^{7}$ and resonance depth of more than 7 dB are theoretically obtained in such resonators with a radius of larger than 5 mm. Furthermore, when these compact PRRs are used as angular velocity sensors, the resolution of better than 10°/h and the angle random walk of less than $0.075 {^{\circ }}/\sqrt {h} $ are theoretically predicted. These characteristics indicate that our proposed compact PRRs are capable of acting as an angular velocity sensor in high efficient monolithically integration of resonant optical gyroscope applications in proof of principle.

Ultrahigh-Q metallic nanocavity resonances with externally-amplified intracavity feedback.

We propose a mechanism of ultrahigh-Q metallic nanocavity resonances that involves an efficient loss-compensation scheme favorable for room-temperature operation. We theoretically show that surface plasmon-polaritons excited on the entrance and exit interfaces of a metallic nanocavity array efficiently transfer external optical gain to the cavity modes by inducing resonantly-amplified intracavity feedback. Surprisingly, the modal gain in the nanocavity with the externally amplified feedback is inversely proportional to the cavity length as opposed to conventional optical cavity amplifiers requiring longer cavities for higher optical gain. Utilizing this effect, we numerically demonstrate room-temperature nanocavity resonance Q-factor exceeding 104 in a 25-nm-wide silver nanoslit array. The proposed mechanism provides a highly efficient plasmonic amplification process particularly for subwavelength plasmonic cavities which are essential components in active nanoplasmonic devices.

Towards improving the robustness of distributed speech recognition in packet loss

This work addresses the problem of achieving robust distributed speech recognition (DSR) performance in the presence of packet loss. The nature of packet loss is analysed by examining packet loss data gathered from a GSM mobile data channel. This analysis is then used to examine the effect of realistic packet loss conditions on DSR systems, and shows that the accuracy of DSR is more sensitive to burst-like packet loss rather than the actual number of lost packets. This leads to the design of a three-stage packet loss compensation scheme. First, interleaving is applied to the transmitted feature vectors to disperse bursts of packet loss. Second, lost feature vectors are reconstructed prior to recognition using a variety of reconstruction techniques. Third, a weighted-Viterbi decoding method is applied to the recogniser itself, which modifies the contribution of the reconstructed feature vectors according to the accuracy of their reconstruction. Experimental results on both a connected digits task and a large-vocabulary task show that simple methods, such as repetition, are not as effective as interpolation methods. Best performance is given by a novel maximum a posteriori (MAP) estimation, which utilizes temporal statistics of the feature vector stream. This reconstruction method is then combined with weighted-Viterbi decoding, using a novel method to calculate the confidences of reconstructed static and temporal components separately. Using interleaving, results improve significantly, and it is shown that a limited level of interleaving can be applied without increasing the delay to the end-user. Using a combination of these techniques for the connected digits task, word accuracy is increased from 49.5% to 95.3% even with a packet loss rate of 50% and average burst length of 20 feature vectors.

DTC of Induction Machines Considering the Iron Loss

The existence of iron loss is normally neglected in derivation of induction machine models. Consequently, all the model-based high-performance control schemes are characterized with a certain amount of iron loss-induced detuning. Consequences of iron loss on operation of vector-controlled induction machines have been examined in detail recently, and numerous methods of iron loss compensation have been suggested. In contrast to such a situation with regard to vector control, it appears that a corresponding study has never been done in conjunction with direct torque control (DTC) of induction machines. The purpose of this paper is twofold. A detailed simulation study is at first performed so that the impact of iron loss on accuracy of the control is examined in detail. Torque mode of operation in the base speed region is considered. It is shown that the net consequence of the iron loss is a substantial difference between the torque reference and the average motor output torque. In contrast to such a situation with regard to motor torque, stator flux estimation is not affected by the iron loss existence. On the basis of the results of detuning investigation, a simple iron loss compensation method is developed. Its accuracy is verified by simulation. Further simplifications of the iron loss compensation scheme are investigated, and it is shown that, for certain machines, iron loss can be effectively compensated by simple deduction of a constant, iron loss-related torque component from the initial torque estimate.

Performance of the COD: A transparent optical TDM statistical packet multiplexor for scalable terabit networks

We have constructed an optically transparent, memoryless 2:1 statistical TDM packet multiplexor for constant packet-length input. This multiplexor is the fundamental building block in a class of Cascaded Optical Delay (COD) multiplexors intended for wide-area terabit networks. The multiplexor does not require slot-aligned traffic. This multiplexor can be cascaded to build multiplexors with improved packet loss rate. In this article we present the experimental packet loss rate of the memoryless multiplexor as well as the calculated packet loss rate of larger, buffered COD multiplexors. Furthermore, we outline an optical loss compensation scheme for buffered COD multiplexors.

Automatic optical loss compensation with erbium-doped fiber amplifier

The effect of unwanted optical loss varying over 15 dB is automatically offset with an erbium-doped fiber amplifier used in an optical feedback configuration. The loss compensation is possible for signal wavelengths over a 13 nm range centered at about 1550 nm. The system dynamic range for loss fluctuation frequencies is zero to several kilohertz. The proposed loss compensation scheme simultaneously provides an automatic gain control function that stabilizes the gain against slow changes in input signal power or pump power.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Variable-bit-rate HDTV codec for ATM networks

A variable-bit-rate HDTV codec based on a motion-adaptive DCT and multimode quantisation is developed for ATM environments in B-ISDN. Adaptive 2-layered coding and error concealment are implemented to keep picture quality high by compensating for ATM cell loss. The codec hardware restricts the peak bit rate to 65 Mbit/s for HDTV conference application and to 130Mbit/s for secondary distribution. Experimental transport shows that the ATM cell loss compensation scheme has good resilience at a cell error rate as high as 10−4.

Experimental HDTV CODEC with ATM cell loss compensation for B-ISDN

An experimental study of HDTV CODEC for transmission in an ATM environment is described. An ATM cell loss compensation scheme is achieved using techniques of two-layered coding, block-interleaving, and data transposition with cell loss detection. Experimental evaluation confirms that the cell loss compensation improves the error rate characteristics of at least three figures for random and burst cell loss, and high picture quality is kept in the ATM cell loss environment of B-ISDN.