1,186,029 research outputs found
Semantics and applications of function graphs
Journal ArticleFunction graphs provide graphical models of programs based on function application. The uses of such models include provision of a semantic framework for functional programs, explication of the structure of complex systems based on function application, increasing proximity of programs to certain application domains, resolution of ambiguities in programs based upon systems of equations, and representation of executable programs in machines based upon data flow execution. Application examples and underlying theory of function graphs are presented
Application of Gr/PMR-15 to commercial aircraft
Following from early experience with polyimides on the SST program and Shuttle aft flap studies the Boeing Company is now working on collaborative programs with its principal nacelle suppliers to pursue the development of Gr/PMR-15 nacelle components. Two programs are currently in effect. The first program is directed specifically towards the flight test and service evaluation at the earliest possible date of a 747 nacelle core cowl structure. The second program seeks to firmly establish the producibility and cost of a 757 thrust reverser C duct in a production environment. The near term objectives of these programs include: (1) the comparison of estimated cost and weight of Gr/PMR-15 versus metal structure, (2) the engine test of representative composite structure, (3) the preliminary design and analysis of the C duct structure, and (4) the preparation of cost data and time schedules for the development and producibility program. In addition to powerplant structure, the propulsion ducting system has shown to be a strong candidate for Gr/PMR-15 application. Currently, the Boeing 747 Organization is evaluating the use of PMR-15 matrix composites to replace nearly 800 lbs of titanium ducting per airplane
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Graph models for reachability analysis of concurrent programs
Reachability analysis is an attractive technique for analysis of concurrent programs because it is simple and relatively straightforward to automate, and can be used in conjunction with model-checking procedures to check for application-specific as well as general properties. Several techniques have been proposed differing mainly on the model used; some of these propose the use of flowgraph based models, some others of Petri nets.This paper addresses the question: What essential difference does it make, if any, what sort of finite-state model we extract from program texts for purposes of reachability analysis? How do they differ in expressive power, decision power, or accuracy? Since each is intended to model synchronization structure while abstracting away other features, one would expect them to be roughly equivalent.We confirm that there is no essential semantic difference between the most well known models proposed in the literature by providing algorithms for translation among these models. This implies that the choice of model rests on other factors, including convenience and efficiency.Since combinatorial explosion is the primary impediment to application of reachability analysis, a particular concern in choosing a model is facilitating divide-and-conquer analysis of large programs. Recently, much interest in finite-state verification systems has centered on algebraic theories of concurrency. Yeh and Young have exploited algebraic structure to decompose reachability analysis based on a flowgraph model. The semantic equivalence of graph and Petri net based models suggests that one ought to be able to apply a similar strategy for decomposing Petri nets. We show this is indeed possible through application of category theory
A Platform-independent Programming Environment for Robot Control
The development of robot control programs is a complex task. Many robots are
different in their electrical and mechanical structure which is also reflected
in the software. Specific robot software environments support the program
development, but are mainly text-based and usually applied by experts in the
field with profound knowledge of the target robot. This paper presents a
graphical programming environment which aims to ease the development of robot
control programs. In contrast to existing graphical robot programming
environments, our approach focuses on the composition of parallel action
sequences. The developed environment allows to schedule independent robot
actions on parallel execution lines and provides mechanism to avoid
side-effects of parallel actions. The developed environment is
platform-independent and based on the model-driven paradigm. The feasibility of
our approach is shown by the application of the sequencer to a simulated
service robot and a robot for educational purpose
Memoization for Unary Logic Programming: Characterizing PTIME
We give a characterization of deterministic polynomial time computation based
on an algebraic structure called the resolution semiring, whose elements can be
understood as logic programs or sets of rewriting rules over first-order terms.
More precisely, we study the restriction of this framework to terms (and logic
programs, rewriting rules) using only unary symbols. We prove it is complete
for polynomial time computation, using an encoding of pushdown automata. We
then introduce an algebraic counterpart of the memoization technique in order
to show its PTIME soundness. We finally relate our approach and complexity
results to complexity of logic programming. As an application of our
techniques, we show a PTIME-completeness result for a class of logic
programming queries which use only unary function symbols.Comment: Soumis {\`a} LICS 201
Software Classification Using Structure-Based Descriptors
With the huge increase of software functionalities, sizes and application domain, the difficulty of categorizing and classifying software packages for reuse and maintenance
purposes is on demand. Building automatic classification mechanism will help to save the budget, time, and the efforts of the organizations, especially the administrators of software repositories. This work includes the use of structure information contained in source code programs to
automate program classification. Three software metrics namely; LOC, MVG and WMCl have been extracted from programs of category board and puzzle obtained from SourceForge.net. A total of 2800 programs have been used during the training process while two different datasets of size (28) were used for testing. Based on the undertaken experiment, the IBK algorithm is noted to generate the highest classification accuracy (74.8%) compared to several other algorithms provided in the Weka tool. The study also shows that board programs are written in different structure compared to the puzzle programs. Hence, showing that structure information can be used to classify programs into application domain
THE EUROPEAN FUNDS – AN ANTI-CRISIS MEASURE AT THE MOMENT
The European funds do not represent an inward purpose, but instruments in reaching the objectives established at the level of the European Union, of the EU member state, based on the implementation documents. The access to Social and Cohesion Funds offers Romania a possibility to develop the regions which are lagging behind, to modernize transport and environment infrastructure, to support rural development, to create new employment opportunities, to sustain social policies which will lead to the growth of the standard of life. The non-reimbursable structural assistance is more the support replaces an important part of the financial effort that should be done by a state on its own, the more helpful and precious is. This research work displays diverse aspects concerning the implementation modalities of irredeemable funds. Furthermore, the existence of a strong institutional structure was absolutely necessary, capable to ensure the formulation and application of public policies, to keep the coordination processes inside ministries going, the implementation of national programs, increasing the application capacity of partnerships between local administrations.structural funds, irredeemable financing, management authorities, regional operation programs, absorption capacity, convergence
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