9,097 research outputs found
1991 NCCD Prison Population Forecast: The Impact of Declining Drug Arrests (FOCUS)
According to the National Council and Crime and Delinquency (NCCD), prison populations will increase by 35 percent over the next five years under the current criminal justice policies. This rate of growth is significantly lower than NCCD's 1989 estimates of a 60 percent increase over five years. The principal reason for the lower growth rate is a 20 percent reduction in drug arrests, which in turn is reducing projected jail and prison admissions. The declining number of drug arrests are related to the fiscal crisis of state and local governments, drug asset and seizure laws, and lower drug use. However, prison populations will continue to grow despite reductions in admissions due to the passage of mandatory minimum sentencing statutes and lengthier prison terms for certain crimes. Assuming that the 16 states researched are representative of trends that are on-going in other states and the Federal Prison System, the nation's prison population will reach 1 million inmates by 1994
Technical Report: A Receding Horizon Algorithm for Informative Path Planning with Temporal Logic Constraints
This technical report is an extended version of the paper 'A Receding Horizon
Algorithm for Informative Path Planning with Temporal Logic Constraints'
accepted to the 2013 IEEE International Conference on Robotics and Automation
(ICRA). This paper considers the problem of finding the most informative path
for a sensing robot under temporal logic constraints, a richer set of
constraints than have previously been considered in information gathering. An
algorithm for informative path planning is presented that leverages tools from
information theory and formal control synthesis, and is proven to give a path
that satisfies the given temporal logic constraints. The algorithm uses a
receding horizon approach in order to provide a reactive, on-line solution
while mitigating computational complexity. Statistics compiled from multiple
simulation studies indicate that this algorithm performs better than a baseline
exhaustive search approach.Comment: Extended version of paper accepted to 2013 IEEE International
Conference on Robotics and Automation (ICRA
Technical Report: Distribution Temporal Logic: Combining Correctness with Quality of Estimation
We present a new temporal logic called Distribution Temporal Logic (DTL)
defined over predicates of belief states and hidden states of partially
observable systems. DTL can express properties involving uncertainty and
likelihood that cannot be described by existing logics. A co-safe formulation
of DTL is defined and algorithmic procedures are given for monitoring
executions of a partially observable Markov decision process with respect to
such formulae. A simulation case study of a rescue robotics application
outlines our approach.Comment: More expanded version of "Distribution Temporal Logic: Combining
Correctness with Quality of Estimation" to appear in IEEE CDC 201
Technical report: Distribution Temporal Logic: combining correctness with quality of estimation
We present a new temporal logic called Distribution Temporal Logic (DTL) defined over predicates of belief states and hidden states of partially observable systems. DTL can express properties involving uncertainty and likelihood that cannot be described by existing logics. A co-safe formulation of DTL is defined and algorithmic procedures are given for monitoring executions of a partially observable Markov decision process with respect to such formulae. A simulation case study of a rescue robotics application outlines our approach
Surface code implementation of block code state distillation
State distillation is the process of taking a number of imperfect copies of a
particular quantum state and producing fewer better copies. Until recently, the
lowest overhead method of distilling states |A>=(|0>+e^{i\pi/4}|1>)/\sqrt{2}
produced a single improved |A> state given 15 input copies. New block code
state distillation methods can produce k improved |A> states given 3k+8 input
copies, potentially significantly reducing the overhead associated with state
distillation. We construct an explicit surface code implementation of block
code state distillation and quantitatively compare the overhead of this
approach to the old. We find that, using the best available techniques, for
parameters of practical interest, block code state distillation does not always
lead to lower overhead, and, when it does, the overhead reduction is typically
less than a factor of three.Comment: 26 pages, 28 figure
Formal methods paradigms for estimation and machine learning in dynamical systems
Formal methods are widely used in engineering to determine whether a system exhibits a certain property (verification) or to design controllers that are guaranteed to drive the system to achieve a certain property (synthesis). Most existing techniques require a large amount of accurate information about the system in order to be successful. The methods presented in this work can operate with significantly less prior information. In the domain of formal synthesis for robotics, the assumptions of perfect sensing and perfect knowledge of system dynamics are unrealistic. To address this issue, we present control algorithms that use active estimation and reinforcement learning to mitigate the effects of uncertainty. In the domain of cyber-physical system analysis, we relax the assumption that the system model is known and identify system properties automatically from execution data.
First, we address the problem of planning the path of a robot under temporal logic constraints (e.g. "avoid obstacles and periodically visit a recharging station") while simultaneously minimizing the uncertainty about the state of an unknown feature of the environment (e.g. locations of fires after a natural disaster). We present synthesis algorithms and evaluate them via simulation and experiments with aerial robots. Second, we develop a new specification language for tasks that require gathering information about and interacting with a partially observable environment, e.g. "Maintain localization error below a certain level while also avoiding obstacles.'' Third, we consider learning temporal logic properties of a dynamical system from a finite set of system outputs. For example, given maritime surveillance data we wish to find the specification that corresponds only to those vessels that are deemed law-abiding. Algorithms for performing off-line supervised and unsupervised learning and on-line supervised learning are presented. Finally, we consider the case in which we want to steer a system with unknown dynamics to satisfy a given temporal logic specification. We present a novel reinforcement learning paradigm to solve this problem. Our procedure gives "partial credit'' for executions that almost satisfy the specification, which can
lead to faster convergence rates and produce better solutions when the specification is not satisfiable
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