Automata Serialization for Manipulation and Drawing

GUItar is a GPL-licensed, cross-platform, graphical user interface for automata drawing and manipulation, written in C++ and Qt5. This tool offers support for styling, automatic layouts, several format exports and interface with any foreign finite automata manipulation library that can parse the serialized XML or JSON produced. In this paper we describe a new redesign of the GUItar framework and specially the method used to interface GUItar with automata manipulation libraries

Implementation of labcreator and the integration of cyberlab

With the development of the World Wide Web, online courses are becoming more and more popular in modern science education. CyberLab aims to solve an important issue in distance science education -- laboratory experiments in online courses. It is a toolkit that handles creation, exportation, and execution of virtual experiments (within web browsers). It consists of LabCreator and LabExecutor. With LabCreator, instructors can create virtual experiments and export them into intermediate files. Students can download those files from online course websites and execute them in LabExecutor on their own computers. The paper reports on the completion of two important tasks in the development of CyberLab: (1) the implementation of LabCreator and (2) a system allowing exportation of the experiment to intermediate web accessible format and the loading of the experiment into LabExecutor. The feasibility of the design and structure of CyberLab is proved by integrating the LabCreator and LabExecutor for the first time. The advantage of CyberLab is shown through a demonstration of the deployment of a virtual experiment

Garden of Eden: Software Packages for the Generation and Rendering of Visually Realistic Trees and Forests

Garden of Eden is an exercise in procedural generation of lifelike worlds. It randomly generates a forest scene of realistically shaped and proportioned asymmetric trees on top of a simple topographical map. This map is then rendered in an HTML5 3D canvas, with support for user navigation. The end result of this project is a sort of game, though without any goal, narrative, or creative purpose. It is simply a static rendering of a natural environment, open for exploration, closed to manipulation, exploring how users find visual pleasure and meaning in virtual environments. The passive interaction of the user is integral to this simulation, as it reflects how one would observe a natural environment; by forcing the user into the same perspective from which they view actual forest environments, Garden of Eden explores the concept of natural, the distinction between real and virtual, and the user\u27s sense of place. All software packages are offered open source, with detailed documentation, for users wishing to create their own arboreal experience

Freely annotating C#

Reflective programming is becoming popular due to the increasing set of dynamic services provided by execution environments like JVM and CLR. With custom attributes Microsoft introduced an extensible model of reflection for CLR: they can be used as additional decorations on element declarations. The same notion has been introduced in Java 1.5. The annotation model, both in Java and in C#, limits annotations to classes and class members. In this paper we describe [a]C#a, an extension of the C# programming language, that allows programmers to annotate statements and code blocks and retrieve these annotations at run-time. We show how this extension can be reduced to the existing model. A set of operations on annotated code blocks to retrieve annotations and manipulate bytecode is introduced. We also discuss how to use [a]C# to annotate programs giving hints on how to parallelize a sequential method and how it can be implemented by means of the abstractions provided by the run-time of the language. Finally, we show how our model for custom attributes has been realized

Proceedings of the Sixth NASA Langley Formal Methods (LFM) Workshop

Today's verification techniques are hard-pressed to scale with the ever-increasing complexity of safety critical systems. Within the field of aeronautics alone, we find the need for verification of algorithms for separation assurance, air traffic control, auto-pilot, Unmanned Aerial Vehicles (UAVs), adaptive avionics, automated decision authority, and much more. Recent advances in formal methods have made verifying more of these problems realistic. Thus we need to continually re-assess what we can solve now and identify the next barriers to overcome. Only through an exchange of ideas between theoreticians and practitioners from academia to industry can we extend formal methods for the verification of ever more challenging problem domains. This volume contains the extended abstracts of the talks presented at LFM 2008: The Sixth NASA Langley Formal Methods Workshop held on April 30 - May 2, 2008 in Newport News, Virginia, USA. The topics of interest that were listed in the call for abstracts were: advances in formal verification techniques; formal models of distributed computing; planning and scheduling; automated air traffic management; fault tolerance; hybrid systems/hybrid automata; embedded systems; safety critical applications; safety cases; accident/safety analysis

A partitioned computation machine

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1990.Includes bibliographical references (leaves 86-88).by Kenneth Brett Streeter.M.S

Optimization of Regular Path Queries in Graph Databases

Regular path queries offer a powerful navigational mechanism in graph databases. Recently, there has been renewed interest in such queries in the context of the Semantic Web. The extension of SPARQL in version 1.1 with property paths offers a type of regular path query for RDF graph databases. While eminently useful, such queries are difficult to optimize and evaluate efficiently, however. We design and implement a cost-based optimizer we call Waveguide for SPARQL queries with property paths. Waveguide builds a query planwhich we call a waveplan (WP)which guides the query evaluation. There are numerous choices in the con- struction of a plan, and a number of optimization methods, so the space of plans for a query can be quite large. Execution costs of plans for the same query can vary by orders of magnitude with the best plan often offering excellent performance. A WPs costs can be estimated, which opens the way to cost-based optimization. We demonstrate that Waveguide properly subsumes existing techniques and that the new plans it adds are relevant. We analyze the effective plan space which is enabled by Waveguide and design an efficient enumerator for it. We implement a pro- totype of a Waveguide cost-based optimizer on top of an open-source relational RDF store. Finally, we perform a comprehensive performance study of the state of the art for evaluation of SPARQL property paths and demonstrate the significant performance gains that Waveguide offers