185 research outputs found
Jewish names in Egypt in the Early Roman period
In this article I claim that in the Roman period, biblical names used by Jews became very limited in comparison with their variety in the Ptolemaic period. I argue that they are mainly represented by the names of the three patriarchs - Abraham, Isaac and Jacob - and of Jacob's son - Joseph. These four names constitute 73% of all biblical names male Jews used in the early Roman period, before the Jewish revolt in 115-117 A.D
Autoresonant Ash Removal in Mirror Machines
Magnetic confinement fusion reactors produce ash particles that must be
removed for efficient operation. It is suggested to use autoresonance (a
continuous phase-locking between anharmonic motion and a chirped drive) to
remove the ash particles from a magnetic mirror, the simplest magnetic
confinement configuration. An analogy to the driven pendulum is established via
the guiding center approximation. The full 3D dynamics is simulated for
particles (the byproduct of DT fusion) in agreement with the
approximated 1D model. Monte Carlo simulations sampling the phase space of
initial conditions are used to quantify the efficiency of the method. The DT
fuel particles are out of the bandwidth of the chirped drive and, therefore,
stay in the mirror for ongoing fusion. The method is also applicable for
advanced, aneutronic reactors, such as p-B.Comment: 5 pages, 4 figure
RF plugging of multi-mirror machines
One of the main challenges of fusion reactors based on magnetic mirrors is
the axial particle loss through the loss cones. In multi-mirror (MM) systems,
the particle loss is addressed by adding mirror cells on each end of the
central fusion cell. Coulomb collisions in the MM sections serve as the
retrapping mechanism for the escaping particles. Unfortunately, the confinement
time in this system only scales linearly with the number of cells in the MM
sections and requires an unreasonably large number of cells to satisfy the
Lawson criterion. Here, it is suggested to reduce the outflow by applying a
traveling RF electric field that mainly targets the particles in the outgoing
loss cone. The Doppler shift compensates for the detuning of the RF frequency
from the ion cyclotron resonance mainly for the escaping particles resulting in
a selectivity effect. The transition rates between the different phase space
populations are quantified via single-particle calculations and then
incorporated into a semi-kinetic rate equations model for the MM system,
including the RF effect. It is found that for optimized parameters, the
confinement time can scale exponentially with the number of MM cells, orders of
magnitude better than a similar MM system of the same length but without the RF
plugging, and can satisfy the Lawson criterion for a reasonable system size
ArcAid: Analysis of Archaeological Artifacts using Drawings
Archaeology is an intriguing domain for computer vision. It suffers not only
from shortage in (labeled) data, but also from highly-challenging data, which
is often extremely abraded and damaged. This paper proposes a novel
semi-supervised model for classification and retrieval of images of
archaeological artifacts. This model utilizes unique data that exists in the
domain -- manual drawings made by special artists. These are used during
training to implicitly transfer the domain knowledge from the drawings to their
corresponding images, improving their classification results. We show that
while learning how to classify, our model also learns how to generate drawings
of the artifacts, an important documentation task, which is currently performed
manually. Last but not least, we collected a new dataset of stamp-seals of the
Southern Levant. Our code and dataset are publicly available.Comment: 8 pages, 9 figure
Topology-Hiding Computation
Secure Multi-party Computation (MPC) is one of the foundational achievements of modern cryptography,
allowing multiple, distrusting, parties to jointly compute a function of their inputs, while revealing nothing but the
output of the function. Following the seminal works of Yao and Goldreich, Micali and Wigderson and Ben-Or, Goldwasser and Wigderson,
the study of MPC has expanded to consider a wide variety of questions, including variants in the attack model,
underlying assumptions, complexity and composability of the resulting protocols.
One question that appears to have received very little attention, however, is that of MPC over an
underlying communication network whose structure is, in itself, sensitive information. This question, in addition to being
of pure theoretical interest, arises naturally in many contexts: designing privacy-preserving social-networks, private peer-to-peer computations,
vehicle-to-vehicle networks and the ``internet of things\u27\u27 are some of the examples.
In this paper, we initiate the study of ``topology-hiding computation\u27\u27 in the computational setting. We give formal definitions
in both simulation-based and indistinguishability-based flavors. We show that, even for fail-stop adversaries, there are some strong
impossibility results. Despite this, we show that protocols for topology-hiding computation can be constructed in the semi-honest
and fail-stop models, if we somewhat restrict the set of nodes the adversary may corrupt
- …