38,051 research outputs found
On Plans With Loops and Noise
In an influential paper, Levesque proposed a formal specification for
analysing the correctness of program-like plans, such as conditional plans,
iterative plans, and knowledge-based plans. He motivated a logical
characterisation within the situation calculus that included binary sensing
actions. While the characterisation does not immediately yield a practical
algorithm, the specification serves as a general skeleton to explore the
synthesis of program-like plans for reasonable, tractable fragments.
Increasingly, classical plan structures are being applied to stochastic
environments such as robotics applications. This raises the question as to what
the specification for correctness should look like, since Levesque's account
makes the assumption that sensing is exact and actions are deterministic.
Building on a situation calculus theory for reasoning about degrees of belief
and noise, we revisit the execution semantics of generalised plans. The
specification is then used to analyse the correctness of example plans.Comment: Proceedings of AAMAS 201
Recommended from our members
Considerations for Future IGS Receivers
Future IGS receivers are considered against the backdrop of GNSS signal modernization
and the IGS’s goal of further improving the accuracy of its products. The purpose of this paper is to
provide IGS members with a guide to making decisions about GNSS receivers. Modernized GNSS signals
are analyzed with a view toward IGS applications. A schedule for minimum IGS receiver requirements
is proposed. Features of idealized conceptual receivers are discussed. The prospects for standard commercial
receivers and for software-defined GNSS receivers are examined. Recommendations are given
for how the IGS should proceed in order to maximally benefit from the transformation in GNSS that
will occur over the next decade.Aerospace Engineering and Engineering Mechanic
The Ursinus Weekly, May 12, 1952
WSGA to install officers at banquet on Thursday • Sororities hold dances, elections • Ruby selects photographer • College physician, famous coach, dies • WAA gives banquet • Bus. Ad. club takes poll • Queen and court reign at May Day pageant • Commencement, Baccalaureate speakers announced • Rosicrucians to entertain new members • Curtain Club, Alpha Psi elect new presidents • Four fraternities pick new officers • Voegler to speak at Pottstown • Campus groups hold annual elections: IRC, FTA, French Club • Queen to be on TV • Editorials: Good idea; Class struggle; Capitalistic noise and smoke • Class of 1952 is invited to Alumni Association dinner • Phila. Story is grand success • Alumni group plans banquet • Pinned • Ursinus routs Pharmacy with twenty run splurge • Snell\u27s Belles win in opener • Feist hurls five hitter, Bears rout Drexel, 9-4 • Physics Department develops film loops for better teaching • Famous columnist and editor speaks to FTA • Plans of \u2752 graduates reveal varied interests • Elizabethtown wins with eight run inning, 10 to 3 • Belles trounce West Chester • Men\u27s tennis squad victor • JV softball team whips Drexel 8-3 • Ursinus cinder men lose close meet to Albright • Ursinus finishes second in track • Y plans hot dog roast for May 14 • Marine representative speaks • Engagement • Marriagehttps://digitalcommons.ursinus.edu/weekly/1544/thumbnail.jp
Gemini multi-conjugate adaptive optics system review II: Commissioning, operation and overall performance
The Gemini Multi-conjugate Adaptive Optics System - GeMS, a facility
instrument mounted on the Gemini South telescope, delivers a uniform, near
diffraction limited images at near infrared wavelengths (0.95 microns- 2.5
microns) over a field of view of 120 arc seconds. GeMS is the first sodium
layer based multi laser guide star adaptive optics system used in astronomy. It
uses five laser guide stars distributed on a 60 arc seconds square
constellation to measure for atmospheric distortions and two deformable mirrors
to compensate for it. In this paper, the second devoted to describe the GeMS
project, we present the commissioning, overall performance and operational
scheme of GeMS. Performance of each sub-system is derived from the
commissioning results. The typical image quality, expressed in full with half
maximum, Strehl ratios and variations over the field delivered by the system
are then described. A discussion of the main contributor to performance
limitation is carried-out. Finally, overheads and future system upgrades are
described.Comment: 20 pages, 11 figures, accepted for publication in MNRA
Distributed State Machine Supervision for Long-baseline Gravitational-wave Detectors
The Laser Interferometer Gravitational-wave Observatory (LIGO) consists of
two identical yet independent, widely-separated, long-baseline
gravitational-wave detectors. Each Advanced LIGO detector consists of complex
optical-mechanical systems isolated from the ground by multiple layers of
active seismic isolation, all controlled by hundreds of fast, digital, feedback
control systems. This article describes a novel state machine-based automation
platform developed to handle the automation and supervisory control challenges
of these detectors. The platform, called \textit{Guardian}, consists of
distributed, independent, state machine automaton nodes organized
hierarchically for full detector control. User code is written in standard
Python and the platform is designed to facilitate the fast-paced development
process associated with commissioning the complicated Advanced LIGO
instruments. While developed specifically for the Advanced LIGO detectors,
Guardian is a generic state machine automation platform that is useful for
experimental control at all levels, from simple table-top setups to large-scale
multi-million dollar facilities.Comment: Version 2: 11 pages, 9 figures. Submitted to Review of Scientific
Instrument
Universality and Realistic Extensions to the Semi-Analytic Simulation Principle in GNSS Signal Processing
Semi-analytic simulation principle in GNSS signal processing bypasses the bit-true operations at high sampling frequency. Instead, signals at the output branches of the integrate&dump blocks are successfully modeled, thus making extensive Monte Carlo simulations feasible. Methods for simulations of code and carrier tracking loops with BPSK, BOC signals have been introduced in the literature. Matlab toolboxes were designed and published. In this paper, we further extend the applicability of the approach. Firstly, we describe any GNSS signal as a special instance of linear multi-dimensional modulation. Thereby, we state universal framework for classification of differently modulated signals. Using such description, we derive the semi-analytic models generally. Secondly, we extend the model for realistic scenarios including delay in the feed back, slowly fading multipath effects, finite bandwidth, phase noise, and a combination of these. Finally, a discussion on connection of this semi-analytic model and position-velocity-time estimator is delivered, as well as comparison of theoretical and simulated characteristics, produced by a prototype simulator developed at CTU in Prague
Are carrier-to-noise algorithms equivalent in all situations?
This paper describes methods to estimate the carrier to noise ratio in GNSS application
- …