nils-herrmann/clean_scirepeval huggingface dataset:
A Set Theoretic Framework for Watermarking and Its Application to Semifragile Tamper Detection

We introduce a set theoretic framework for watermarking. Multiple requirements, such as watermark embedding strength, imperceptibility, robustness to benign signal processing, and fragility under malicious attacks are described as constraint sets and a watermarked image is determined as a feasible solution satisfying these constraints. We illustrate that several constraints can be formulated as convex sets and develop a watermarking algorithm based on the method of projections onto convex sets. The framework allows flexible incorporation of different constraints, including embedding strength requirements for multiple watermarks that share the same spatial context and different imperceptibility requirements based on frequency-weighted error and local texture perceptual models. We illustrate the effectiveness of the framework by designing a hierarchical semifragile watermark that is tolerant to mild compression, allows tamper localization, and is fragile under aggressive compression. Using a quad-tree representation, a spatial resolution hierarchy is established on the image and a watermark is embedded corresponding to each node of the hierarchy. The spatial hierarchy of watermarks provides a graceful tradeoff between robustness and localization under mild JPEG compression, where watermarks at coarser levels demonstrate progressively higher immunity to JPEG compression. Under aggressive compression, watermarks at all hierarchy levels vanish, indicating a lack of trust in the image data. The constraints implicitly partition watermark power in the resolution hierarchy as well as among image regions based on robustness and invisibility requirements. Experimental results illustrate the flexibility and effectiveness of the method
A tipping pulse scheme for a rf-SQUID qubit

We present a technique to control the quantum state of a rf-SQUID qubit. We propose to employ a stream of single flux quantum (SFQ) pulses magnetically coupled to the qubit junction to momentarily suppress its critical current. This effectively lowers the barrier in the double-well rf SQUID potential thereby increasing the tunneling oscillation frequency between the wells. By carefully choosing the time interval between SFQ pulses one may accelerate the interwell tunneling rate. Thus it is possible to place the qubit into a chosen superposition of flux states and then effectively to freeze the qubit state. We present both numerical simulations and analytical time-dependent perturbation theory calculations that demonstrate the technique. Using this strategy one may control the quantum state of the rf SQUID in a way analogous to the /spl pi/ pulses in other qubit schemes.
A phase sensitive SIS mixer to circumvent the quantum limit

A conventional superconductor-insulator-superconductor (SIS) mixer, that is pumped by a single-frequency local oscillator (LO) functions as a phase-insensitive linear amplifier and may achieve a noise level near the quantum limit of one-half photon added noise per unit bandwidth. A phase-sensitive linear amplifier may have less noise than this quantum limit. To overcome the quantum noise limit with an SIS mixer, a two-LO technique which makes the mixer's gain dependent upon the phase of the incoming signal was used. The phase sensitive gain of this two-LO mixer is experimentally demonstrated. The gain variation from maximum to minimum is more than 20 dB. Theoretical predictions of the noise of the two-LO mixer are presented.
High speed testing of a four-bit RSFQ decimation digital filter

We have developed a high speed test scheme for RSFQ circuits, in order to measure the maximum clock frequency of a four-bit RSFQ decimation digital filter (simulated to be 11 GHz). Our high speed test requires only a low speed interface and standard low-cost measurement equipment. Three auxiliary test units built of simple RSFQ circuits are used. A circular JTL structure generates an on-chip high speed clock with frequency adjustable from 4 to 16 GHz. A pseudo-random number generator with period 64 clock cycles provides parallel input to the filter. Finally, 12 four-bit acquisition shift registers collect output data. We have integrated all the above units on a single chip. The chip is initialized at low speed, run at high speed, and read out at low speed. Our testing scheme is superior to previously reported high-speed tests in the area of the added circuitry, in the requirements on high-speed input/output, in control, and in the parameters of the measurement equipment. The scheme can be easily adapted to test various RSFQ circuits.
An unshunted comparator as a device for quantum measurements

The unshunted single-flux-quantum SFQ comparator is described for the first time. Its dynamic behavior is surprisingly similar to the familiar resistively-shunted SFQ comparator. For certain parameter ranges both junctions of the comparator may pulse at the same time to create a reflected anti-pulse. This phenomenon is utilized in a new SFQ comparator design with better coherence properties for qubit readout. Considerations of quantum noise for the unshunted SFQ comparator are discussed.
What makes music musical? a framework for extracting performance expression and emotion in musical sound

We present a framework to provide a quantitative representation of aspects of musical sound that are associated with musical expressiveness and emotions. After a brief introduction to the background of expressive features in music, we introduce a score to audio mapping algorithm based on dynamic time warping, which segments the audio by comparing it to a music score. Expressive feature extraction algorithms are then introduced. The algorithms extract an expressive feature set that includes pitch deviation, loudness, timbre, timing, articulation, and modulation from the segmented audio to construct an expressive feature database. We have demonstrated these tools in the context of solo western classical music, specifically for the solo oboe. We also discuss potential applications to music performance education and music “language” processing.
Representation of solo clarinet music by physical modeling synthesis

A physical modeling synthesizer is developed and used to parametrically represent digital audio recordings of clarinet soloists. Empirical data, in the form of acoustic impedance measurements, are incorporated in the model definition. Reed dynamics are also included. Algorithms which calculate control parameters from source recordings are presented and examples of both the impedance measurements and the synthesis output are provided. The synthesis results give further support to the idea that music can, in certain circumstances, be adequately represented by a few low bandwidth control parameters. Additionally, the governing equations of clarinet physical modeling are briefly reviewed.
Noise model of indirect-feedback sigma-delta image sensors

A novel architecture for a CMOS image sensor that incorporates a column-level sigma-delta (ΣΔ) analog-to-digital converter is presented. An indirect-feedback readout architecture where the digital output of the ΣΔ modulator is accumulated by a digital counter and converted to an analog voltage that serves as the reference voltage to which the buffered photodiode voltage is compared is shown. A time-domain pixel simulator that enables assessment of major noise contributors in this type of imager is also presented. Theoretical calculations align with simulation results, showing a minimum readout noise of 2.18e- and a dynamic range of over 100dB. A prototype chip has been developed in TSMC's 0.35-μm technology and its performance will be assessed.
Phase sensitive heterodyne receivers with SIS quasiparticle mixers

It is noted that it is possible to operate a mixer as a phase-sensitive linear amplifier by pumping with two local oscillators (LOs) separated in frequency by twice the IF (intermediate frequency) and symmetrically located about the signal frequency. In principle a phase-sensitive amplifier can detect a signal without adding any noise. The authors present a formalism developed to describe two-LO mixers, and extend the quantum mixer theory to calculate expressions for the gain and noise of a two-LO mixer. The full quantum mechanical formulation used here enables an analysis of the mixer noise for general input states, for example, a squeezed state. It is demonstrated that a two-LO mixer is phase-sensitive. The results are pertinent to the design of phase-sensitive heterodyne receivers with SIS (superconductor-insulator-superconductor) quasiparticle mixers.
Measurement of jitter in a long Josephson junction soliton oscillator clock source

Stability of Josephson junction clock sources can be a limiting factor in the operation of RSFQ digital and mixed signal circuits. We have developed techniques for the characterization of the short-term stability, i.e., the jitter, of Josephson junction clock sources, and in this paper we present measurements of the jitter for a long Josephson junction soliton oscillator clock. The output frequency of the soliton oscillator was prescaled by using a chain of T flip-flops and using a current bias feedback the oscillator was phase locked to a stable room temperature RP source. Phase noise spectra of the clock signal were measured at the successive stages of the T flip-flop chain and interpreted to infer the cycle-to-cycle jitter of the soliton oscillator. The jitter at the output of the soliton oscillator was measured to be 60 fs at a frequency of 26 GHz, or 0.16% of the period of the clock.
A RF superconducting electromechanical transducer for gravitational wave antennae

An electromechanical transducer based on a superconducting radiofrequency bridge circuit has been developed for use on a gravitational radiation detector. The low electrical loss of superconductors has made it possible to achieve electrical quality factors of several thousand in a lumped-element circuit which operates at 4 MHz. The bridge could be remotely balanced to one part in 50000, which led to a displacement noise level of 10/sup -15/ m/ square root Hz. It should be useful in measuring any physical quantity which can be made to change a capacitance. At the present stage of development, capacitance changes of 10/sup -20/ F could be detected in a 1-s integration time. One straightforward improvement, namely, the use of a low-phase-noise quartz crystal oscillator as the bridge excitation source will reduce the noise to 10/sup -17/ m/ square root Hz.
Predicting the near-future impact of daily activities on heart rate for at-risk populations

In this paper we demonstrate the ability to predict changes to heart rate due to changes in levels of activity, up to an hour into the future. Activity levels are calculated from data collected by a worn accelerometer for a person performing daily activities outside a laboratory environment. People with congestive heart failure must take care not to excessively stress their heart. This can be a challenge due to the difficulty of predicting how much stress an activity is exerting on the heart. We propose to model the relationship between motion and heart rate and thus to enable the prediction of heart rate changes prior to performing an activity. We explored three methods to predict current and future heart rate from activity level: a continuous state Kalman Filter, two simple linear models, and a nonlinear model given in the literature . The results from healthy subjects and subjects with congestive heart failure show that using the proposed models, the heart rate can be predicted an hour into the future using accelerometer data.
Design and testing of QOS comparators for an RSFQ based analog to digital converter

Successful utilization of the quasi one-junction SQUID (QOS) as a signal comparator for analog-to-digital conversion (ADC) has been demonstrated by several groups, This idea is extended to show how similar comparators can be integrated into an all rapid single flux quantum (RSFQ) digital architecture. Comparators are interrogated by SFQ sampling pulses and in turn give output according to the RSFQ convention. One- and two-bit ADC's have been simulated, fabricated and tested at low speed. Total performance of these devices is estimated within the framework of a multiple bit parallel flash ADC architecture.<<ETX>>
Evaluation of a vibration-powered, wireless temperature sensor for health monitoring

RLW, Inc designed and built a prototype vibration-powered, wireless temperature sensor for condition based maintenance (CBM) applications. To reduce installation and maintenance costs, the CBM industry is turning increasingly toward wireless sensors, but a major impediment to more widespread implementation of wireless sensors for CBM is that many are powered by batteries that must be regularly replaced. The sensor described in this paper eliminates that problem because power to operate the sensor is generated from ambient vibrations of the device to which the sensor is mounted. This paper describes the design approach and preliminary laboratory test results of the prototype sensor. The sensor will run indefinitely, reporting its temperature once per minute if vibration levels of the machine to which it is mounted are 0.2 g RMS or greater (at the generator's resonant frequency - 88, 96, 101, 108 Hz described in this testing). When the platform vibration stopped the sensor for an additional 60 to 120 minutes (with reporting rages ranging from every minute to once an hour) before turning itself off until vibration input is restored
Non-contact ECG employing signal compensation

Non-contact ECG monitoring is an attractive option in a number of applications such as long-term health monitoring where traditional adhesive ECG sensors would cause skin irritation and require frequent replacement. Also, integrating ECG sensors into furniture, automobile seats and elsewhere in the environment will enable non-invasive sensing of cardiac signals. Subject-electrode relative motion causes spurious signals and significant signal distortion. The ECG signal of interest as well as static charge and electromagnetic interference are modulated by changes in the coupling capacitance between the electrodes and subject, which leads to significant distortions. The focus of this paper is the development of a non-contacting ECG sensing system including the electrodes, interface electronics and a signal-processing unit that work together to address this issue. The subject-to-electrode distance is continuously monitored by a secondary sensing circuit that uses the ECG electrodes themselves which serve as both the primary ECG readout and the secondary subject-to-electrode distance readout. Finally, the experimental results show the secondary readout signal can be used to compensate the motion-related gain variations of the primary ECG monitoring circuit as well as the additive interference by motion events.
Source rendering on dynamic audio displays

We describe a design for an “audio display”, a loudspeaker that employs the bending vibrations of a panel, such as flat-panel television screen or projection surface, to render localized sound sources anywhere on the surface of the panel. The method employs a two-dimensional Fourier series reconstruction of the desired panel spatial vibration profile, and an array of force actuators affixed to the panel to selectively control its bending modes. The parameters of the signal filters required to drive the actuator array are based upon the intended panel spatial vibration profile and the resonant frequencies and quality factors of the panel modes. A computationally efficient method to dynamically control the locations of the audio sources on the audio display surface is described. Laser vibrometer measurements of a prototype show that the method can be used for real-time control of sound source locations, which allows audio sources and their corresponding video features to be spatially aligned to give viewers a greater sense of media immersion.
Ultra-low overhead signal acquisition circuit for capacitive and piezoelectric sensors

Driven by the defense, medical, and automotive markets, the demand for low-cost, low-overhead sensors for precision signal acquisition has increased by more than 200% since 2001. However, a growing number of sensor applications necessitate wireless operation, and, therefore, impose significant constraints on the acquisition and processing subsystems, which interface to these sensors. The goal of this work is to present a novel capacitive sensor interface circuit that is capable of accurately estimating the power in a user-defined frequency band in remarkably energy-efficient manner. This switched-capacitor-based implementation is designed in TSMCpsilas 0.35-mum mixed-mode CMOS technology and consumes a scant 30 muW, comparable to the leakage power of a 10-g Li-ion battery.
A fully-differential switched capacitor chopper stabilized high-pass filter (mirrored integrator)

This work presents a new design for fully differential, high-pass switched-capacitor (SC) filter. The frequency dependence of the filter transfer function is the mirrored image (around one-half of the Nyquist frequency) of the low-pass integrator transfer function, thus we refer to the new filter as the "mirrored integrator" (MI). The MI will be a key element in the design of Nyquist band signal processing applications such as two-path band-pass /spl Sigma//spl Delta/ analog to digital converters (ADC's) and high-pass /spl Sigma//spl Delta/ ADC's. A chopper stabilization method is inherently employed in the design to suppress the DC offset and 1/f noise of the opamp.
Inherently Stable Weighted Least-Squares Estimation of Common Acoustical Poles With the Application in Feedback Path Modeling Utilizing a Kautz Filter

In adaptive feedback cancellation, the feedback path must be modeled precisely using as few adaptive parameters as possible to reduce computational complexity and enable rapid convergence. To reduce the number of adaptive parameters, the feedback path is usually modeled with a transfer function composed of an invariant component and a variable component using all-pole, all-zero, and pole-zero filters. These filters may be inefficient, requiring a large number of parameters for their specification, particularly in reverberant environments. In this letter, we present a weighted least-squares algorithm to precisely estimate the common poles of feedback paths, and we then model the invariant basis functions employing a Kautz filter. The Kautz filter is defined by a set of the fixed poles and a corresponding set of tap output weights. The fixed poles are associated with prominent peaks that are common to the measured feedback path frequency responses. The algorithm guarantees unconditionally the stability of the estimated poles of the inferred model. The experimental results using measured acoustic feedback paths from a two-microphone, behind-the-ear hearing aid show that the proposed method provides an accurate model of the feedback paths for a variety of acoustic environments that were not employed in estimating the common poles.
Robust analog circuit design: a set theoretic approach

A set theoretic methodology for analog/RF circuit design is introduced that finds robust design parameters as a feasible solution meeting multiple constraints. The parametric design is determined so as to satisfy multiple requirements such as circuit power, device sizes, area, transistor bias conditions, small signal characteristics and other design requirements using the method of projections onto convex sets (POCS). A nested projection structure is utilized to project onto complicated, possibly non-convex constraints. The process variations are stochastically modelled and a further adjustment is proposed on sets to achieve robustness. The effectiveness of the method is illustrated by a partial design of a two stage operational amplifier
Optimal Spread Spectrum Watermark Embedding via a Multistep Feasibility Formulation

We consider optimal formulations of spread spectrum watermark embedding where the common requirements of watermarking, such as perceptual closeness of the watermarked image to the cover and detectability of the watermark in the presence of noise and compression, are posed as constraints while one metric pertaining to these requirements is optimized. We propose an algorithmic framework for solving these optimal embedding problems via a multistep feasibility approach that combines projections onto convex sets (POCS) based feasibility watermarking with a bisection parameter search for determining the optimum value of the objective function and the optimum watermarked image. The framework is general and can handle optimal watermark embedding problems with convex and quasi-convex formulations of watermark requirements with assured convergence to the global optimum. The proposed scheme is a natural extension of set-theoretic watermark design and provides a link between convex feasibility and optimization formulations for watermark embedding. We demonstrate a number of optimal watermark embeddings in the proposed framework corresponding to maximal robustness to additive noise, maximal robustness to compression, minimal frequency weighted perceptual distortion, and minimal watermark texture visibility. Experimental results demonstrate that the framework is effective in optimizing the desired characteristic while meeting the constraints. The results also highlight both anticipated and unanticipated competition between the common requirements for watermark embedding.
Data hiding via phase manipulation of audio signals

Data hiding in media, including images, video, and audio, and in data files is currently of great interest both commercially, mainly for the protection of copyrighted digital media, and to the government and law enforcement in the context of information system security and covert communications. We present a technique for inserting and recovering "hidden" data in audio files. The phase of chosen components of the host audio signal is manipulated in a way that may be detected by a receiver with the proper "key". Without the key, the hidden data is undetectable, both aurally and via blind digital signal processing attacks. The method described is both aurally transparent and robust and can be applied to both analog and digital audio signals, the latter including uncompressed as well as compressed audio file formats such as MP3.
Beating the quantum limit in SIS mixers

The 2LO (double local oscillator) mixer is analyzed in the low-LO-power limit for a perfect SIS (superconductor-insulator-superconductor) diode. It is shown that a 2LO SIS mixer can beat the noise performance of a one-LO mixer by a factor of two. It is suggested that even lower noise is possible with an SIS when operated in some other way.
Numerical computation of two-LO SIS mixer gain and noise

The authors present numerical calculations of the gain and noise of a two-LO (local oscillator) mixer based on an ideal SIS (superconductor-insulator-superconductor) IV curve. They demonstrate the phase-sensitive response of the mixer with two-LO pumping and present calculations of the noise for various DC bias conditions and embedding impedances. Preliminary results indicate that for certain DC bias conditions and signal terminations, the noise added to a signal by the two-LO mixer operated in the single-sideband mode can be a factor of 25 less than that added by a conventional single-sideband single-LO mixer.