arXiv subjects

Dan Cohen

Publications and source records attributed to Dan Cohen.

4 recordsLinked to original sources

arXiv2025

Cognitive Trust in HRI: "Pay Attention to Me and I'll Trust You Even if You are Wrong"

Cognitive trust and the belief that a robot is capable of accurately performing tasks, are recognized as central factors in fostering high-quality human-robot interactions. It is well established that performance factors such as the robot's competence and its reliability shape cognitive trust. Recent studies suggest that affective factors, such as robotic attentiveness, also play a role in building cognitive trust. This work explores the interplay between these two factors that shape cognitive trust. Specifically, we evaluated whether different combinations of robotic competence and attentiveness introduce a compensatory mechanism, where one factor compensates for the lack of the other. In the experiment, participants performed a search task with a robotic dog in a 2x2 experimental design that included two factors: competence (high or low) and attentiveness (high or low). The results revealed that high attentiveness can compensate for low competence. Participants who collaborated with a highly attentive robot that performed poorly reported trust levels comparable to those working with a highly competent robot. When the robot did not demonstrate attentiveness, low competence resulted in a substantial decrease in cognitive trust. The findings indicate that building cognitive trust in human-robot interaction may be more complex than previously believed, involving emotional processes that are typically overlooked. We highlight an affective compensatory mechanism that adds a layer to consider alongside traditional competence-based models of cognitive trust.

cs.RO↗

arXiv2020

Timing Detectors with SiPM read-out for the MUSE Experiment at PSI

The Muon Scattering Experiment at the Paul Scherrer Institut uses a mixed beam of electrons, muons, and pions, necessitating precise timing to identify the beam particles and reactions they cause. We describe the design and performance of three timing detectors using plastic scintillator read out with silicon photomultipliers that have been built for the experiment. The Beam Hodoscope, upstream of the scattering target, counts the beam flux and precisely times beam particles both to identify species and provide a starting time for time-of-flight measurements. The Beam Monitor, downstream of the scattering target, counts the unscattered beam flux, helps identify background in scattering events, and precisely times beam particles for time-of-flight measurements. The Beam Focus Monitor, mounted on the target ladder under the liquid hydrogen target inside the target vacuum chamber, is used in dedicated runs to sample the beam spot at three points near the target center, where the beam should be focused.

physics.ins-det↗

arXiv2018

iMAP Beamforming for High Quality High Frame Rate Imaging

We present a statistical interpretation of beamforming to overcome limitations of standard delay-and-sum (DAS) processing. Both the interference and the signal of interest are viewed as random variables and the distribution of the signal of interest is exploited to maximize the a-posteriori distribution of the aperture signals. In this formulation the beamformer output is a maximum-a-posteriori (MAP) estimator of the signal of interest. We provide a closed form expression for the MAP beamformer and estimate the unknown distribution parameters from the available aperture data using an empirical Bayes approach. We propose a simple scheme that iterates between estimation of distribution parameters and computation of the MAP estimator of the signal of interest, leading to an iterative MAP (iMAP) beamformer. This results in a significant improvement of the contrast compared to DAS without severe increase in computational complexity or need for fine-tuning of parameters. By implementing iMAP on both simulated and experimental data, we show that only 13 transmissions are required to obtain contrast comparable to DAS with 75 plane-waves. The proposed method is compared to other interference suppression techniques such as coherence factor and scaled Wiener processing and shows improved contrast and better preserved speckle pattern.

cs.IT↗

arXiv2017

Calibration Of Proton Accelerator Beam Energy

When studying the 7Li(p,n)7Be reaction with a RF accelerator, it is difficult to define the precise energy of the beam and its energy distribution, which together fully define the beam, for our purpose. What we do know is the difference between two given energies. We resolve this problem by finding a reference energy and then finding another energy by examining the data, relative to the reference energy. From the difference between them we can approximate the energy distribution for a given energy, and since we know the energy threshold of the reaction (E_threshold for 7Li(p,n)7Be is about 1880.4-1880.8 (keV)) we can calibrate the beam energy. We then determine the energy which produce the maximum yield derivative as the reference and record the energy whose neutron yield is 5% of the reference energy. The data is collected by simulating this reaction using SimLit. Since this is a simulation we know the real energy distribution so we make a linear fit for energy distribution as function of energy difference. We tested the theory on experimental data for which we approximate the energy distribution by other means, and found our new method to be accurate and satisfactory for our needs.

physics.ins-det↗