nils-herrmann/clean_scirepeval huggingface dataset:
Application of an Envelope-Domain Time-Series Model of an RF Power Amplifier to the Development of a Digital Pre-Distorter System

A behavioral model of a 200W Doherty RF power amplifier has been created from digitally-modulated IQ signal information using an established nonlinear time series approach. The model operates in the envelope or digital signal domain and is implemented in Matlab so that it can be used directly in system-level simulators. The model has been validated using measured data. It has been used in a system-level design and simulation of digital pre-distorter systems, where the high fidelity of the model to the measured data and the rapid speed of simulation have enabled the system design
Broad-band, multi-harmonic frequency domain behavioral models from automated large-signal vectorial network measurements

This paper presents an extended nonlinear black-box behavioral model in the frequency domain, automated experimental identification of the model from large-signal vector network measurements, and extensive experimental validation of its application to real microwave ICs. The model is a broad-band extension of the multi-harmonic "linearized scattering function" theory. The characterization is based on large-signal vector network measurements where harmonic perturbations are applied, in phase and in quadrature, to a component excited at the input by a large amplitude tone. The experiment design and model generation are simple and highly automated. The derived model is shown to be valid for both small and large amplitude drive signals, correctly predict even and odd harmonics, and simulate, accurately, load-pull behavior far from 50 ohms. The model is implemented in Agilent ADS.
Performance control over heterogeneous receivers for video multicast

Multiple Description with Forward Error Correction coding (MDFEC) provides the flexibility, easy adaptivity and distortion-rate optimality that are desirable for delivering streaming video in a network environment with time-varying bandwidth fluctuations and random packet losses. In this paper, we consider the issue of trading-off the performance between clusters of receivers with low access-link bandwidth (such as wireless users) and receivers with high access-link bandwidth (such as wired users). We show that the average distortion of the low-bandwidth cluster is a non-decreasing function of an introduced weighting factor λ while that of high-bandwidth receivers is a non-increasing function of λ. In other words, the difference of average distortion between low-bandwidth and high-bandwidth receivers can be controlled monotonically by the introduced weighting factor λ. We also provide experimental verification as a function of λ for various numbers of descriptions using group of pictures (GOP) from well-known Foreman and Akiyo CIF test clips.
Player classification in interactive sport scenes using prior information region space analysis and number recognition

This paper proposes using a novel region space technique to track sport persons for the purpose of extracting their shirt numbers and use this to provide augmented information to the viewer. The region adjacency graph and picture trees are used to perform a search for an object using prior knowledge from a scene description. Once the candidate object has been extracted the sub-space is examined for alphanumeric characters, which are then characterized by optical character recognition. Rogue candidates may be removed based on the recognition histograms with improved robustness using temporal analysis.
Very near ground RF propagation measurements for wireless systems

Using a forward control channel of two different base stations as the signal source, we measure the effects associated with placing a cellular/PCS handheld transceiver very near the ground. A significant decrease in signal strength occurs when a system user drops from a standing to a lying position. As much as a 10.9 dB decrease in signal strength can result. This effect occurs with either a weak or strong specular signal component. Additionally, when a strong specular signal component, the shadowing caused by the system user's head is small compared to the variations caused by antenna elevation.
Implementation of an embodied general reinforcement learner on a serial link manipulator

BECCA (a Brain-Emulating Cognition and Control Architecture software package) was developed in order to perform general reinforcement learning, that is, to enable unmodeled embodied systems operating in unstructured environments to perform unfamiliar tasks. It accomplishes this through automatic paired feature creation and reinforcement learning algorithms. This paper describes an implementation of BECCA on a seven Degree of Freedom (DoF) Barrett Whole Arm Manipulator (WAM) undergoing a series of experiments designed to test the reinforcement learner's ability to adapt to the WAM hardware. In the experiments, the following is demonstrated, 1) learning to transition the WAM between states, 2) learning to perform at near optimal levels on one, two and three dimensional navigation tasks, 3) applying learning in simulation to hardware performance, 4) learning under inconsistent, human-generated reward, and 5) combining the reinforcement learner with Probabilistic Roadmap Methods (PRM) to improve scalability. The goal of the paper is to demonstrate both the scalability of the BECCA reinforcement learning approach using different formulations of the state space and to show the approach in this paper operating on complex physical hardware.
Linearity considerations for a high power Doherty amplifier

This paper proposes the calculation of memory residual (MR) and adjacent channel power ratio (ACPR) as figures-of-merit (FOM) for the analysis of linearizability of a high power RF Doherty amplifier circuit. Two-tone and wideband code division multiple access (WCDMA) signals of increasing bandwidths and varying power levels are used for the calculation of the MR and ACPR performance respectively. It is found that MR and ACPR performances are not only dependent on the input signal power to the high power amplifier (HPA) but these metrics are also dependent on the bandwidth of the signal used. Agreement is found in MR and ACPR performance trends for the increasing input power and signal bandwidths. For the investigation of linearizability and ACPR measurements of the Doherty HPA, various predistorter (Memory Polynomial and Volterra-series based) schemes are used. The Volterra-series based predistorter scheme using dynamic deviation reduction (Volterra DDR) is found to give the best ACPR performance in the presence of significant memory effects. For the validation, simulation and hardware measurements of MR and ACPR performances are presented for high power Doherty power amplifier circuits operating at 2.14GHz.
Resolution Scalable Motion-Compensated JPEG 2000

This paper proposes two motion-compensated extensions to JPEG 2000 for the efficient scalable compression of video. The first one is a rather conventional pyramid coder with MCTF on each spatial level and a closed loop coding structure. The second one is a novel open-loop coder that preserves the full scalability of the high-spatial level. We show that for certain reasonable values of high-resolution and low- resolution bitrates that both coders have approximately equal performance, with the new open-loop coder retaining full scalability advantages.
Tomographic time-frequency analysis and its application toward time-varying filtering and adaptive kernel design for multicomponent linear-FM signals

Since line integrals through the Wigner spectrum can be calculated by dechirping, calculation of the Wigner spectrum may be viewed as a tomographic reconstruction problem. In the paper, the authors show that all time-frequency transforms of Cohen's class may be achieved by simple changes in backprojection reconstruction filtering. The resolution/cross-term tradeoff that occurs in time-frequency kernel selection is shown to be analogous to the resolution-ringing tradeoff that occurs in computed tomography (CT). "Ideal" reconstruction using a purely differentiating backprojection filter yields the Wigner distribution, whereas low-pass differentiating filters produce cross-term suppressing distributions such as the spectrogram or the Born-Jordan distribution. It is also demonstrated how this analogy can be exploited to "tune" the reconstruction filtering (or time-frequency kernel) to improve the ringing/resolution tradeoff. Some properties of the projection domain, which is also known as the Radon-Wigner transform, are characterized, including the response to signal delays or frequency shifts and projection masking or convolution. Last, time-varying filtering by shift-varying convolution in the Radon-Wigner domain is shown to yield superior results to its analogous Cohen's class adaptive transform (shift-invariant convolution) for the multicomponent, linear-FM signals that are investigated.
Sliding block entropy coding of images

The authors compare various options for combining linear prediction with vector quantization for purposes of image coding. A previously developed algorithm called sliding block predictive vector quantization (SBPVQ) is extended with multiple-level quantizers (i.e. n>2), and is compared to vector-predictive quantization (VPQ). The particular version considered here is termed sliding block vector predictive quantization (SBVPQ) and uses a (M,L) tree search on the encoded blocks. Arithmetic coding is used to transmit the SBPVQ and SBVPQ encoded data at rates closer to their output entropy than rates obtained with fixed-rate coding.<<ETX>>
Multiple model recursive estimation of images

In this paper, we demonstrate the application of the reduced update Kalman filter in the enhancement of two-dimensional images using a composite model description of the image. Typically, for the purpose of simulation, five models corresponding to four predominant correlation directions (at angles of 0°, 45°, 90°, 135° to the horizontal) and one isotropic model, are considered. These models are then used to synthesize a filtering algorithm that estimates the image with near minimum mean square error. The results show considerable improvement in the visual quality compared with linear constant coefficient Kalman filtering.
Design of stable 2-D half-plane recursive filters using spectral factorization

In this paper a new design algorithm for two-dimensional (2-D) recursive digital filters is presented, with emphasis on the general class of half-plane filters. A recently developed 2-D spectral factorization procedure and a nonlinear optimization algorithm are incorporated to iteratively converge to a stable, (locally) optimum filter. Details of the computations required in the implementation of the design procedure are presented, in addition to an example of its application.
MPEG Motion Picture Coding With Long-Term Constraint on Distortion Variation

A highly desirable feature in storage video applications is uniform quality. Variable bit rate (VBR) coding has the potential to produce nearly constant quality throughout an entire movie. This can be defined as a bit allocation problem with a long-term constraint on distortion variation. We consider the optimal bit allocation with multiple constraints including disk capacity and the distortion bounds on the individual frames. We find the theoretical optimality conditions and propose a practical iterative solution based on the Lagrangian methods. While minimizing average distortion and distortion variation cannot be achieved simultaneously for a given bit budget, the proposed algorithms are able to efficiently balance the tradeoff between the two goals. The computational complexity of the exact rate-distortion (R - D) functions for real movies is addressed by a statistical R - D model proposed in this work. Based on the generic block-based motion compensated transform coding theories, the model is formed by a rate-quantization (R - Q) function and the corresponding distortion-quantization (D - Q) function. A novel two-pass MPEG-2 VBR encoder based on the proposed algorithms is developed for coding with long-term nearly constant quality. Experimental results are promising and the encoder effectively achieves the fit-to-disc function and at the same time controls objective quality variation. By incorporating basic subjective coding techniques into the encoder, significant visual quality improvement is observed during the subjective tests.
Bias-dependent linear, scalable millimeter-wave FET model

This paper describes a measurement-based bias-dependent linear equivalent circuit field-effect-transistor/high-electron-mobility-transistor model that is accurate to at least 100 GHz and scalable up to 12 parallel gate fingers and from 100 to 1000 /spl mu/m total gate width. A new and accurate technique for extracting the Z-shell parameters has been developed, and the scaling rules for all the parasitic elements have been determined. The intrinsic equivalent circuit element values are determined at each bias point in V/sub ge/-V/sub ds/ space and interpolated by splines between points.
Image restoration by parallel simulated annealing using compound Gauss-Markov models

A parallel simulated annealing algorithm is presented for image restoration using a compound Gauss-Markov field model for the image. Results are provided for its implementation on a distributed array processor (DAP510) which is a single instruction multiple data (SIMD) machine with 1024(32*32) mesh-connected processor elements, and a clock rate of 10 MHz. The total time required for restoring a monochrome blurred and noisy image with continuous range of intensities is reduced to about 10 minutes as compared to 20 hours for its sequential implementation (VAX11/785). Both the maximum a posteriori (MAP) and minimum mean square error (MMSE) estimates of the original image are obtained. The parallel estimates are shown, as well as the sequential estimate and the classical Wiener filter estimate.<<ETX>>
Parallel realizations of 2-D recursive Kalman filters

This paper presents parallel realizations of the two-dimensional reduced update Kalman filter. It is shown that sufficiently spaced pixels on certain diagonals may be predicted and updated in parallel. This parallelism is then exploited on a conventional shared memory parallel processor and timings are reported. Predicted performance is provided for area-array SIMD type parallel processors, e.g. CLIP4 and CLIP7.
Predictive Vector Quantization of Images

The purpose of this paper is to present new image coding schemes based on a predictive vector quantization (PVQ) approach. The predictive part of the encoder is used to partially remove redundancy, and the VQ part further removes the residual redundancy and selects good quantization levels for the global waveform. Two implementations of this coding approach have been devised, namely, sliding block PVQ and block tree PVQ. Simulations on real images show significant improvement over the conventional DPCM and tree codes using these new techniques. The strong robustness property of these coding schemes is also experimentally demonstrated.
Intersection filters for general decimation/Interpolation

Optimum multiple stopband FIR filters for decimation or interpolation by integer factors have been presented in the literature. In this correspondence we extend these results to the case of general decimation/interpolation by rational factors. The resulting filters are called intersection filters because their stopbands are intersections of the stopbands required in the case of integer factors. Significant improvement in stopband attenuation is found in many cases for band-limited signals.
Investigation for Single-Event Upset in MSI Devices

This paper describes the results of the first known test for cosmic-ray effects exclusively directed towards several MSI logic families containing flip-flops, since Binder et al postulated the explanation for anomalous bit flips in 1975. The test was performed as a result of a joint effort between the Jet Propulsion Laboratory and MIT Lincoln Laboratory using the University of California (Berkeley) 88" Cyclotron. Five (5) technologies were tested for their susceptibility to both "hard" and "soft" failure mechanisms attributable to cosmic rays. Each of these types (low-power TTL, standard TTL, low-power Schottky, Schottky, and CMOS) exhibited differing degrees of susceptibility to singleevent upsets.
System-Level Design Considerations for Digital Pre-Distortion of Wireless Base Station Transmitters

Over the past 25 years or so there has been much interest in the use of digital pre-distortion (DPD) techniques for the linearization of RF and microwave power amplifiers. In this paper, we describe the important system and hardware requirements for the four main subsystems found in the DPD linearized transmitter: RF/analog, data converters, digital signal processing, and the DPD architecture and algorithms, and illustrate how the overall DPD system architecture is influenced by the design choices that may be made in each of these subsystems. We shall also consider the challenges presented to future applications of DPD systems for wireless communications, such as higher operating frequencies, wider signal bandwidths, greater spectral efficiency signals, resulting in higher peak-to-average power ratios, multiband and multimode operation, lower power consumption requirements, faster adaption, and how these affect the system design choices.
Power Efficiency and Linearity Enhancement Using Optimized Asymmetrical Doherty Power Amplifiers

This paper investigates the virtues of the asymmetrical Doherty power amplifier (PA) for improving the average power efficiency, linearity, and peak envelope power. It commences with an in-depth study of the effects of increasing the size of the peaking amplifier's transistor and its conduction angle on the Doherty PA's RF performance. In particular, the impact of the extended current profile of the peaking amplifier and reduced turn-on effects on the soft-turn characteristic are thoroughly analyzed, and their impacts on the average efficiency and peak power are deduced. Furthermore, the aggravation of the memory effects that accompany the gm3-based nonlinear distortion cancellation is experimentally demonstrated. Two asymmetrical Doherty PAs prototypes are fabricated using 80 W and 150 W laterally diffused metal oxide semiconductor field-effect transistors to individually improve average efficiency and linearity. When driven with a four carrier wideband code division multiple access (4C-WCDMA) signal, the asymmetrical Doherty PA allowed for excellent drain efficiency of approximately 50%, along with high linearity of approximately -50 dBc , using a memory polynomial digital predistorter at an average output power of 50 W. To the best of the authors' knowledge, this achieved efficiency is the highest reported in the literature for a high-power Doherty PA implemented in LDMOS technology.
Cerebral blood flow and predictors of white matter lesions in adults with Tetralogy of Fallot

Long-term outcomes for Tetralogy of Fallot (TOF) have improved dramatically in recent years, but survivors are still afflicted by cerebral damage. In this paper, we characterized the prevalence and predictors of cerebral silent infarction (SCI) and their relationship to cerebral blood flow (CBF) in 46 adult TOF patients. We calculated both whole brain and regional CBF using 2D arterial spin labeling (ASL) images, and investigated the spatial overlap between voxel-wise CBF values and white matter hyperintensities (WMHs) identified from T2-FLAIR images. SCIs were found in 83% of subjects and were predicted by the year of the patient's first cardiac surgery and patient's age at scanning (combined r2 0.44). CBF was not different in brain regions prone to stroke compared with healthy white matter.
Integrating renewables into the grid: Applying UltraBattery® Technology in MW scale energy storage solutions for continuous variability management

Electricity providers are increasingly faced with the challenge to integrate variable renewable generation with the existing portfolio and the electricity grid. The UltraBattery® technology, an entire new class of advanced lead-acid batteries invented by the CSIRO, now allows the continuous management of variability and shifting of energy, crucial for the large scale integration of renewables. The UltraBattery® has already been successfully implemented globally in several MW scale energy storage projects to demonstrate: · The endurance and longevity of the UltraBattery® to manage the ramp rate of renewable energy and to shift renewables output; · The outperformance of the UltraBattery® in the provision of regulation services over incumbent gas peakers often used for regulation services; and · The potential to reduce the cost of each MWh of storage used to control renewable energy variability. The demonstration projects have proven the ability of Ultra-Battery® technology to combine renewable energy sources with a storage system, thus providing multiple benefits to making renewable resources reliable and dispatchable.
Establishing Object Correspondences by Utilizing Surrounding Information

Tracking objects in motion is often done by imposing the constraints of kinematics and local image properties onto the objects. In this work, we propose a novel tracking algorithm which uses the surrounding information of the object to construct the feature profiles. The object feature profiles are then compared across consecutive frames to locate the targets. The feature profiles possess two important properties, distinctive-ness and coherence, which make them robust to measurement noises, short occlusions and false targets. The matching cost function is formulated under a Bayesian framework that enables the algorithm to capture the properties in the form of probabilities. The algorithm is also self-initializing. The computation of the feature profiles is fast due to their simple definition; and the comparison between two profiles can also be done efficiently.
Intelligent management and control of received wireless power

The concept of powering a remote device without wires is known as a wireless power transfer system. Some applications employ batteries while others use storage capacitors instead. In either case, it is necessary to transfer enough power to enable the receiver to do the required work. This paper presents an intelligent algorithm to manage received wireless power to do useful work even though there is insufficient power to do the work directly. The example ultra-low power microcontroller discussed here is the ATTiny85 although the approach is applicable to a whole family of similar micros. The algorithm used makes intelligent decisions whether to sleep or wake according to the amount of received and stored energy. Using an adaptive strategy of this kind the amount of work can be precisely matched to the resources available to achieve maximum utilization. The paper also evaluates the performance of the proposed algorithm compared with more conventional ways of doing the same thing.