49 research outputs found
Nonperturbative photon light front wave functions from a contact interaction model
We propose a method to calculate the light front wave functions
(LFWFs) of photon at low-virtuality, i.e., the light front amplitude of
at low , based on a light front projection
approach. We exemplify this method using a contact interaction model within
Dyson-Schwinger equations formalism and obtain the nonperturbative photon
LFWFs. In this case, we find the nonperturbative effects are encoded
in the enhanced quark mass and a dressing function of covariant quark-photon
vertex, as compared to the leading order quantum electrodynamics photon
LFWFs. We then use nonperturbative-effect modified photon
LFWFs to study the inclusive deep inelastic scattering HERA data in the
framework of the color dipole model. The results demonstrate that the
theoretical description of data at low can be significantly improved once
the nonperturbative corrections are included in the photon LFWFs.Comment: 11 pages, 4 figure
Fight Fire with Fire: Combating Adversarial Patch Attacks using Pattern-randomized Defensive Patches
Object detection has found extensive applications in various tasks, but it is
also susceptible to adversarial patch attacks. Existing defense methods often
necessitate modifications to the target model or result in unacceptable time
overhead. In this paper, we adopt a counterattack approach, following the
principle of "fight fire with fire," and propose a novel and general
methodology for defending adversarial attacks. We utilize an active defense
strategy by injecting two types of defensive patches, canary and woodpecker,
into the input to proactively probe or weaken potential adversarial patches
without altering the target model. Moreover, inspired by randomization
techniques employed in software security, we employ randomized canary and
woodpecker injection patterns to defend against defense-aware attacks. The
effectiveness and practicality of the proposed method are demonstrated through
comprehensive experiments. The results illustrate that canary and woodpecker
achieve high performance, even when confronted with unknown attack methods,
while incurring limited time overhead. Furthermore, our method also exhibits
sufficient robustness against defense-aware attacks, as evidenced by adaptive
attack experiments
BDTS: Blockchain-based Data Trading System
Trading data through blockchain platforms is hard to achieve \textit{fair
exchange}. Reasons come from two folds: Firstly, guaranteeing fairness between
sellers and consumers is a challenging task as the deception of any
participating parties is risk-free. This leads to the second issue where
judging the behavior of data executors (such as cloud service providers) among
distrustful parties is impractical in the context of traditional trading
protocols. To fill the gaps, in this paper, we present a
\underline{b}lockchain-based \underline{d}ata \underline{t}rading
\underline{s}ystem, named BDTS. BDTS implements a fair-exchange protocol in
which benign behaviors can get rewarded while dishonest behaviors will be
punished. Our scheme requires the seller to provide consumers with the correct
encryption keys for proper execution and encourage a rational data executor to
behave faithfully for maximum benefits from rewards. We analyze the strategies
of consumers, sellers, and dealers in the trading game and point out that
everyone should be honest about their interests so that the game will reach
Nash equilibrium. Evaluations prove efficiency and practicability.Comment: ICICS 2023 (Best Paper Award
A high speed direct digital frequency synthesizer realized by a segmented nonlinear DAC
This paper presents a high speed ROM-less direct digital frequency synthesizer (DDFS) which has a phase resolution of 32 bits and a magnitude resolution of 10 bits. A 10-bit nonlinear segmented DAC is used in place of the ROM look-up table for phase-to-sine amplitude conversion and the linear DAC in a conventional DDFS.The design procedure for implementing the nonlinear DAC is presented. To ensure high speed, current mode logic (CML) is used. The chip is implemented in Chartered 0.35μm COMS technology with active area of 2.0 × 2.5 mm~2 and total power consumption of 400 mW at a single 3.3 V supply voltage. The maximum operating frequency is 850 MHz at room temperature and 1.0 GHz at 0 ℃
Differentially Private Continual Monitoring of Heavy Hitters from Distributed Streams
Abstract. We consider applications scenarios where an untrusted aggregator wishes to continually monitor the heavy-hitters across a set of distributed streams. Since each stream can contain sensitive data, such as the purchase history of customers, we wish to guarantee the privacy of each stream, while allowing the untrusted aggregator to accurately detect the heavy hitters and their approximate frequencies. Our protocols are scalable in settings where the volume of streaming data is large, since we guarantee low memory usage and processing overhead by each data source, and low communication overhead between the data sources and the aggregator.