4,097 research outputs found
Verifying Computations with Streaming Interactive Proofs
When computation is outsourced, the data owner would like to be assured that
the desired computation has been performed correctly by the service provider.
In theory, proof systems can give the necessary assurance, but prior work is
not sufficiently scalable or practical. In this paper, we develop new proof
protocols for verifying computations which are streaming in nature: the
verifier (data owner) needs only logarithmic space and a single pass over the
input, and after observing the input follows a simple protocol with a prover
(service provider) that takes logarithmic communication spread over a
logarithmic number of rounds. These ensure that the computation is performed
correctly: that the service provider has not made any errors or missed out some
data. The guarantee is very strong: even if the service provider deliberately
tries to cheat, there is only vanishingly small probability of doing so
undetected, while a correct computation is always accepted. We first observe
that some theoretical results can be modified to work with streaming verifiers,
showing that there are efficient protocols for problems in the complexity
classes NP and NC. Our main results then seek to bridge the gap between theory
and practice by developing usable protocols for a variety of problems of
central importance in streaming and database processing. All these problems
require linear space in the traditional streaming model, and therefore our
protocols demonstrate that adding a prover can exponentially reduce the effort
needed by the verifier. Our experimental results show that our protocols are
practical and scalable.Comment: VLDB201
Quantiles over data streams : experimental comparisons, new analyses, and further improvements
A fundamental problem in data management and analysis is to generate descriptions of the distribution of data. It is most common to give such descriptions in terms of the cumulative distribution, which is characterized by the quantiles of the data. The design and engineering of efficient methods to find these quantiles has attracted much study, especially in the case where the data are given incrementally, and we must compute the quantiles in an online, streaming fashion. While such algorithms have proved to be extremely useful in practice, there has been limited formal comparison of the competing methods, and no comprehensive study of their performance. In this paper, we remedy this deficit by providing a taxonomy of different methods and describe efficient implementations. In doing so, we propose new variants that have not been studied before, yet which outperform existing methods. To illustrate this, we provide detailed experimental comparisons demonstrating the trade-offs between space, time, and accuracy for quantile computation
Frequency Estimation Under Multiparty Differential Privacy: One-shot and Streaming
We study the fundamental problem of frequency estimation under both privacy
and communication constraints, where the data is distributed among parties.
We consider two application scenarios: (1) one-shot, where the data is static
and the aggregator conducts a one-time computation; and (2) streaming, where
each party receives a stream of items over time and the aggregator continuously
monitors the frequencies. We adopt the model of multiparty differential privacy
(MDP), which is more general than local differential privacy (LDP) and
(centralized) differential privacy. Our protocols achieve optimality (up to
logarithmic factors) permissible by the more stringent of the two constraints.
In particular, when specialized to the -LDP model, our protocol
achieves an error of using bits of communication and
bits of public randomness, where is the size of the domain
Analysis and Implementation of an Ultra-Wide Tuning Range CMOS Ring-VCO With Inductor Peaking
A novel ring voltage controlled oscillator (VCO) topology is proposed which uses monolithic inductors as a peaking load. Four design examples have been fabricated and tested to verify the proposed circuit structure. The highest measured oscillation frequency is 25.07 GHz, with a tuning range of more than four octaves, and the active area is 0.0085 mm2. The design has the highest combined frequency and tuning range with the best figure of merit (≈ 195) comparable to previously published work
The Benefits of Diligence: How Precise are Predicted Gravitational Wave Spectra in Models with Phase Transitions?
Models of particle physics that feature phase transitions typically provide
predictions for stochastic gravitational wave signals at future detectors and
such predictions are used to delineate portions of the model parameter space
that can be constrained. The question is: how precise are such predictions?
Uncertainties enter in the calculation of the macroscopic thermal parameters
and the dynamics of the phase transition itself. We calculate such
uncertainties with increasing levels of sophistication in treating the phase
transition dynamics. Currently, the highest level of diligence corresponds to
careful treatments of the source lifetime; mean bubble separation; going beyond
the bag model approximation in solving the hydrodynamics equations and
explicitly calculating the fraction of energy in the fluid from these equations
rather than using a fit; and including fits for the energy lost to vorticity
modes and reheating effects. The lowest level of diligence incorporates none of
these effects. We compute the percolation and nucleation temperatures, the mean
bubble separation, the fluid velocity, and ultimately the gravitational wave
spectrum corresponding to the level of highest diligence for three explicit
examples: SMEFT, a dark sector Higgs model, and the real singlet-extended
Standard Model (xSM). In each model, we contrast different levels of diligence
in the calculation and find that the difference in the final predicted signal
can be several orders of magnitude. Our results indicate that calculating the
gravitational wave spectrum for particle physics models and deducing precise
constraints on the parameter space of such models continues to remain very much
a work in progress and warrants care.Comment: 43 pages, 16 figures, 1 tabl
Structure-function analysis of the Bacillus megaterium GerUD spore germinant receptor protein.
Germination of Bacillus spores is triggered by the interaction of germinant molecules with specialized receptor proteins localized to the spore inner membrane. Germinant receptors (GRs) are comprised typically of three interacting protein subunits, each of which is essential for receptor function. At least some GRs appear to have a fourth component, referred to as a D-subunit protein. A number of D-subunit proteins were shown previously to be capable of modulating the activity of associated GRs. Here, we investigate the topology and structure-function relationships of the Bacillus megaterium QM B1551 GerUD protein, which is associated with the GerU GR. The presented data demonstrate that GerUD can be subjected to relatively extensive structural modifications while retaining function. Indeed, the presence of either of the two transmembrane spanning domains is sufficient to modulate an efficient GerU-mediated germinative response. The precise function of D-subunit proteins has yet to be established, although they may act as molecular chaperones within the spore inner-membrane environment.S.G was the recipient of a RA Fisher bursary award from Gonville and Caius College, University of Cambridge. X.Z is the recipient of an EPSRC Doctoral Training Grant.This is the final version of the article. It was first available from OUP via http://dx.doi.org/10.1093/femsle/fnv21
Interpreting forest and grassland biome productivity utilizing nested scales of image resolution and biogeographical analysis
Several hardware, software, and data collection problems encountered were conquered. The Geographic Information System (GIS) data from other systems were converted to ERDAS format for incorporation with the image data. Statistical analysis of the relationship between spectral values and productivity is being pursued. Several project sites, including Jackson, Pope, Boulder, Smokies, and Huntington Forest are evolving as the most intensively studied areas, primarily due to availability of data and time. Progress with data acquisition and quality checking, more details on experimental sites, and brief summarizations of research results and future plans are discussed. Material on personnel, collaborators, facilities, site background, and meetings and publications of the investigators are included
A 30 Gb/s CMOS driver integrated with silicon photonics MZM
A voltage mode modulator driver is proposed in the TSMC 65nm low power CMOS process. In the electrical testing, the driver itself can achieve a bit rate of 40Gb/s with the single-ended output swing of 1.65V. Unlike equivalent CML modulator drivers, when the proposed driver is integrated with the silicon photonic MZM, it does not require an additional biasing network. The integrated electro-optic transmitter can achieve 30Gb/s with an extinction ratio of 4.05dB, with the power consumption of main driver being 323mW
Analysis and implementation of an ultra-wide tuning range CMOS ring-VCO with inductor peaking
A novel ring voltage controlled oscillator (VCO) topology is proposed which uses monolithic inductors as a peaking load. Four design examples have been fabricated and tested to verify the proposed circuit structure. The highest measured oscillation frequency is 25.07 GHz, with a tuning range of more than four octaves, and the active area is 0.0085 mm². The design has the highest combined frequency and tuning range with the best figure of merit (~ 195) comparable to previously published work
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