7,731 research outputs found
Relational Representations in Reinforcement Learning: Review and Open Problems
This paper is about representation in RL.We discuss some of the concepts in representation and generalization in reinforcement learning and argue for higher-order representations, instead of the commonly used propositional representations. The paper contains a small review of current reinforcement learning systems using higher-order representations, followed by a brief discussion. The paper ends with research directions and open problems.\u
A geodatabase for multisource data applied to cultural heritage: The case study of Villa Revedin Bolasco
In this paper we present the results of the development of a Web-based archiving and documenting system aimed to the management of multisource and multitemporal data related to cultural heritage. As case study we selected the building complex of Villa Revedin Bolasco in Castefranco Veneto (Treviso, Italy) and its park. Buildings and park were built in XIX century after several restorations of the original XIV century area. The data management system relies on a geodatabase framework, in which different kinds of datasets were stored. More specifically, the geodatabase elements consist of historical information, documents, descriptions of artistic characteristics of the building and the park, in the form of text and images. In addition, we used also floorplans, sections and views of the outer facades of the building extracted by a TLS-based 3D model of the whole Villa. In order to manage and explore these rich dataset, we developed a geodatabase using PostgreSQL and PostGIS as spatial plugin. The Web-GIS platform, based on HTML5 and PHP programming languages, implements the NASA Web World Wind virtual globe, a 3D virtual globe we used to enable the navigation and interactive exploration of the park. Furthermore, through a specific timeline function, the user can explore the historical evolution of the building complex
The geometry of quantum learning
Concept learning provides a natural framework in which to place the problems
solved by the quantum algorithms of Bernstein-Vazirani and Grover. By combining
the tools used in these algorithms--quantum fast transforms and amplitude
amplification--with a novel (in this context) tool--a solution method for
geometrical optimization problems--we derive a general technique for quantum
concept learning. We name this technique "Amplified Impatient Learning" and
apply it to construct quantum algorithms solving two new problems: BATTLESHIP
and MAJORITY, more efficiently than is possible classically.Comment: 20 pages, plain TeX with amssym.tex, related work at
http://www.math.uga.edu/~hunziker/ and http://math.ucsd.edu/~dmeyer
Italian center for Astronomical Archives publishing solution: modular and distributed
The Italian center for Astronomical Archives tries to provide astronomical
data resources as interoperable services based on IVOA standards. Its VO
expertise and knowledge comes from active participation within IVOA and VO at
European and international level, with a double-fold goal: learn from the
collaboration and provide inputs to the community. The first solution to build
an easy to configure and maintain resource publisher conformant to VO standards
proved to be too optimistic. For this reason it has been necessary to re-think
the architecture with a modular system built around the messaging concept,
where each modular component speaks to the other interested parties through a
system of broker-managed queues. The first implemented protocol, the Simple
Cone Search, shows the messaging task architecture connecting the parametric
HTTP interface to the database backend access module, the logging module, and
allows multiple cone search resources to be managed together through a
configuration manager module. Even if relatively young, it already proved the
flexibility required by the overall system when the database backend changed
from MySQL to PostgreSQL+PgSphere. Another implementation test has been made to
leverage task distribution over multiple servers to serve simultaneously: FITS
cubes direct linking, cubes cutout and cubes positional merging. Currently the
implementation of the SIA-2.0 standard protocol is ongoing while for TAP we
will be adapting the TAPlib library. Alongside these tools a first
administration tool (TASMAN) has been developed to ease the build up and
maintenance of TAP_SCHEMA-ta including also ObsCore maintenance capability.
Future work will be devoted at widening the range of VO protocols covered by
the set of available modules, improve the configuration management and develop
specific purpose modules common to all the service components.Comment: SPIE Astronomical Telescopes + Instrumentation 2018, Software and
Cyberinfrastructure for Astronomy V, pre-publishing draft proceeding (reduced
abstract
Design and implementation of an integrated surface texture information system for design, manufacture and measurement
The optimised design and reliable measurement of surface texture are essential to guarantee the functional performance of a geometric product. Current support tools are however often limited in functionality, integrity and efficiency. In this paper, an integrated surface texture information system for design, manufacture and measurement, called âCatSurfâ, has been designed and developed, which aims to facilitate rapid and flexible manufacturing requirements. A category theory based knowledge acquisition and knowledge representation mechanism has been devised to retrieve and organize knowledge from various Geometrical Product Specifications (GPS) documents in surface texture. Two modules (for profile and areal surface texture) each with five components are developed in the CatSurf. It also focuses on integrating the surface texture information into a Computer-aided Technology (CAx) framework. Two test cases demonstrate design process of specifications for the profile and areal surface texture in AutoCAD and SolidWorks environments respectively
A Theory of Formal Synthesis via Inductive Learning
Formal synthesis is the process of generating a program satisfying a
high-level formal specification. In recent times, effective formal synthesis
methods have been proposed based on the use of inductive learning. We refer to
this class of methods that learn programs from examples as formal inductive
synthesis. In this paper, we present a theoretical framework for formal
inductive synthesis. We discuss how formal inductive synthesis differs from
traditional machine learning. We then describe oracle-guided inductive
synthesis (OGIS), a framework that captures a family of synthesizers that
operate by iteratively querying an oracle. An instance of OGIS that has had
much practical impact is counterexample-guided inductive synthesis (CEGIS). We
present a theoretical characterization of CEGIS for learning any program that
computes a recursive language. In particular, we analyze the relative power of
CEGIS variants where the types of counterexamples generated by the oracle
varies. We also consider the impact of bounded versus unbounded memory
available to the learning algorithm. In the special case where the universe of
candidate programs is finite, we relate the speed of convergence to the notion
of teaching dimension studied in machine learning theory. Altogether, the
results of the paper take a first step towards a theoretical foundation for the
emerging field of formal inductive synthesis
A query processing system for very large spatial databases using a new map algebra
Dans cette thĂšse nous introduisons une approche de traitement de requĂȘtes pour des bases de donnĂ©e spatiales. Nous expliquons aussi les concepts principaux que nous avons dĂ©fini et dĂ©veloppĂ©: une algĂšbre spatiale et une approche Ă base de graphe utilisĂ©e dans l'optimisateur. L'algĂšbre spatiale est dĂ©fini pour exprimer les requĂȘtes et les rĂšgles de transformation pendant les diffĂ©rentes Ă©tapes de l'optimisation de requĂȘtes. Nous avons essayĂ© de dĂ©finir l'algĂšbre la plus complĂšte que possible pour couvrir une grande variĂ©tĂ© d'application. L'opĂ©rateur algĂ©brique reçoit et produit seulement des carte. Les fonctions reçoivent des cartes et produisent des scalaires ou des objets. L'optimisateur reçoit la requĂȘte en expression algĂ©brique et produit un QEP (Query Evaluation Plan) efficace dans deux Ă©tapes: gĂ©nĂ©ration de QEG (Query Evaluation Graph) et gĂ©nĂ©ration de QEP. Dans premiĂšre Ă©tape un graphe (QEG) Ă©quivalent de l'expression algĂ©brique est produit. Les rĂšgles de transformation sont utilisĂ©es pour transformer le graphe a un Ă©quivalent plus efficace. Dans deuxiĂšme Ă©tape un QEP est produit de QEG passĂ© de l'Ă©tape prĂ©cĂ©dente. Le QEP est un ensemble des opĂ©rations primitives consĂ©cutives qui produit les rĂ©sultats finals (la rĂ©ponse finale de la requĂȘte soumise au base de donnĂ©e). Nous avons implĂ©mentĂ© l'optimisateur, un gĂ©nĂ©rateur de requĂȘte spatiale alĂ©atoire, et une base de donnĂ©e simulĂ©e. La base de donnĂ©e spatiale simulĂ©e est un ensemble de fonctions pour simuler des opĂ©rations spatiales primitives. Les requĂȘtes alĂ©atoires sont soumis Ă l'optimisateur. Les QEPs gĂ©nĂ©rĂ©es sont soumis au simulateur de base de donnĂ©es spatiale. Les rĂ©sultats expĂ©rimentaux sont utilisĂ©s pour discuter les performances et les caractĂ©ristiques de l'optimisateur.Abstract: In this thesis we introduce a query processing approach for spatial databases and explain the main concepts we defined and developed: a spatial algebra and a graph based approach used in the optimizer. The spatial algebra was defined to express queries and transformation rules during different steps of the query optimization. To cover a vast variety of potential applications, we tried to define the algebra as complete as possible. The algebra looks at the spatial data as maps of spatial objects. The algebraic operators act on the maps and result in new maps. Aggregate functions can act on maps and objects and produce objects or basic values (characters, numbers, etc.). The optimizer receives the query in algebraic expression and produces one efficient QEP (Query Evaluation Plan) through two main consecutive blocks: QEG (Query Evaluation Graph) generation and QEP generation. In QEG generation we construct a graph equivalent of the algebraic expression and then apply graph transformation rules to produce one efficient QEG. In QEP generation we receive the efficient QEG and do predicate ordering and approximation and then generate the efficient QEP. The QEP is a set of consecutive phases that must be executed in the specified order. Each phase consist of one or more primitive operations. All primitive operations that are in the same phase can be executed in parallel. We implemented the optimizer, a randomly spatial query generator and a simulated spatial database. The query generator produces random queries for the purpose of testing the optimizer. The simulated spatial database is a set of functions to simulate primitive spatial operations. They return the cost of the corresponding primitive operation according to input parameters. We put randomly generated queries to the optimizer, got the generated QEPs and put them to the spatial database simulator. We used the experimental results to discuss on the optimizer characteristics and performance. The optimizer was designed for databases with a very large number of spatial objects nevertheless most of the concepts we used can be applied to all spatial information systems."--RĂ©sumĂ© abrĂ©gĂ© par UMI
Searchable Sky Coverage of Astronomical Observations: Footprints and Exposures
Sky coverage is one of the most important pieces of information about
astronomical observations. We discuss possible representations, and present
algorithms to create and manipulate shapes consisting of generalized spherical
polygons with arbitrary complexity and size on the celestial sphere. This shape
specification integrates well with our Hierarchical Triangular Mesh indexing
toolbox, whose performance and capabilities are enhanced by the advanced
features presented here. Our portable implementation of the relevant spherical
geometry routines comes with wrapper functions for database queries, which are
currently being used within several scientific catalog archives including the
Sloan Digital Sky Survey, the Galaxy Evolution Explorer and the Hubble Legacy
Archive projects as well as the Footprint Service of the Virtual Observatory.Comment: 11 pages, 7 figures, submitted to PAS
- âŠ