6,644 research outputs found
Towards Secure and Safe Appified Automated Vehicles
The advancement in Autonomous Vehicles (AVs) has created an enormous market
for the development of self-driving functionalities,raising the question of how
it will transform the traditional vehicle development process. One adventurous
proposal is to open the AV platform to third-party developers, so that AV
functionalities can be developed in a crowd-sourcing way, which could provide
tangible benefits to both automakers and end users. Some pioneering companies
in the automotive industry have made the move to open the platform so that
developers are allowed to test their code on the road. Such openness, however,
brings serious security and safety issues by allowing untrusted code to run on
the vehicle. In this paper, we introduce the concept of an Appified AV platform
that opens the development framework to third-party developers. To further
address the safety challenges, we propose an enhanced appified AV design schema
called AVGuard, which focuses primarily on mitigating the threats brought about
by untrusted code, leveraging theory in the vehicle evaluation field, and
conducting program analysis techniques in the cybersecurity area. Our study
provides guidelines and suggested practice for the future design of open AV
platforms
DIFFERENCE OF HYDROSTATIC WEIGHTING AND SKINFOLD METHODS IN DETERMINATON OF BODY FAT IN CHINESE ADULTS
INTRODUCTION: Body fat content can be determined by Hydrostatic weighing method and skin fold measurement. The former is the most accurate and is thought as “golden Standard”, while the later is an easy and simple way. Measurement of body fat content using skin fold method is by calculation based on the measured skin fold. But the formulas used to calculate body fat content were developed based on the studies in foreigners. We hypothesized that there was significant difference in the body fat content of Chinese determined by hydrostatic weighing and skin fold methods in which the formula was from the studies in foreigners. The formula developed based on the study in foreigners might not be suitable in the determination of body fat content in Chinese
Chemical logic gates on active colloids
Synthetic active colloidal systems are being studied extensively because of
the diverse and often unusual phenomena these nonequilibrium systems manifest,
and their potential applications in fields ranging from biology to material
science. Recent studies have shown that active colloidal motors that use
enzymatic reactions for propulsion hold special promise for applications that
require motors to carry out active sensing tasks in complicated biomedical
environments. In such applications it would be desirable to have active
colloids with some capability of computation so that they could act
autonomously to sense their surroundings and alter their own dynamics to
perform specific tasks. Here we describe how small chemical networks that make
use of enzymatic chemical reactions on the colloid surface can be used to
construct motor-based chemical logic gates. Some basic features of coupled
enzymatic reactions that are responsible for propulsion and underlie the
construction and function of chemical gates are described using continuum
theory and molecular simulation. Examples are given that show how colloids with
specific chemical logic gates can perform simple sensing tasks. Due to the
diverse functions of different enzyme gates, operating alone or in circuits,
the work presented here supports the suggestion that synthetic motors using
such gates could be designed to operate in an autonomous way in order to
complete complicated tasks
Regge trajectories for the heavy-light diquarks
We attempt to apply the Regge trajectory approach to the heavy-light diquarks
composed of one heavy quark and one light quark. However, we find that the
direct application of the usual Regge trajectory formula for the heavy-light
mesons and baryons fails. In order to correctly estimate the masses of the
heavy-light diquarks, it is needed to consider the light quark mass correction
and the parameter in the Cornell potential within
the Regge trajectory formula. By using the modified Regge trajectory formulas,
we are able to estimate the masses of the heavy-light diquarks , ,
and , which agree with other theoretical results. It is
illustrated that the heavy-light diquarks satisfy the universal descriptions
irrespective of heavy quark flavors, similar to other heavy-light systems such
as the heavy-light mesons, the heavy-light baryons composed of one heavy quark
(diquark) and one light diquark (quark), and the heavy-light tetraquarks
composed of one heavy diquark (antidiquark) and one light antidiquark
(diquark). The diquark Regge trajectory provides a new and very simple approach
for estimating the spectra of the heavy-light diquarks.Comment: 9 pages, 3 figures, 6 tables. arXiv admin note: text overlap with
arXiv:2305.1570
Transformers Learn Higher-Order Optimization Methods for In-Context Learning: A Study with Linear Models
Transformers are remarkably good at in-context learning (ICL) -- learning
from demonstrations without parameter updates -- but how they perform ICL
remains a mystery. Recent work suggests that Transformers may learn in-context
by internally running Gradient Descent, a first-order optimization method. In
this paper, we instead demonstrate that Transformers learn to implement
higher-order optimization methods to perform ICL. Focusing on in-context linear
regression, we show that Transformers learn to implement an algorithm very
similar to Iterative Newton's Method, a higher-order optimization method,
rather than Gradient Descent. Empirically, we show that predictions from
successive Transformer layers closely match different iterations of Newton's
Method linearly, with each middle layer roughly computing 3 iterations. In
contrast, exponentially more Gradient Descent steps are needed to match an
additional Transformers layer; this suggests that Transformers have an
comparable rate of convergence with high-order methods such as Iterative
Newton, which are exponentially faster than Gradient Descent. We also show that
Transformers can learn in-context on ill-conditioned data, a setting where
Gradient Descent struggles but Iterative Newton succeeds. Finally, we show
theoretical results which support our empirical findings and have a close
correspondence with them: we prove that Transformers can implement
iterations of Newton's method with layers
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