64,560 research outputs found
Prototyping the Semantics of a DSL using ASF+SDF: Link to Formal Verification of DSL Models
A formal definition of the semantics of a domain-specific language (DSL) is a
key prerequisite for the verification of the correctness of models specified
using such a DSL and of transformations applied to these models. For this
reason, we implemented a prototype of the semantics of a DSL for the
specification of systems consisting of concurrent, communicating objects. Using
this prototype, models specified in the DSL can be transformed to labeled
transition systems (LTS). This approach of transforming models to LTSs allows
us to apply existing tools for visualization and verification to models with
little or no further effort. The prototype is implemented using the ASF+SDF
Meta-Environment, an IDE for the algebraic specification language ASF+SDF,
which offers efficient execution of the transformation as well as the ability
to read models and produce LTSs without any additional pre or post processing.Comment: In Proceedings AMMSE 2011, arXiv:1106.596
Object orientation and visualization of physics in two dimensions
We present a generalized framework for cellular/lattice based visualizations
in two dimensions based on state of the art computing abstractions. Our
implementation takes the form of a library of reusable functions written in C++
which hides complex graphical programming issues from the user and mimics the
algebraic structure of physics at the Hamiltonian level. Our toolkit is not
just a graphics library but an object analysis of physical systems which
disentangles separate concepts in a faithful analytical way. It could be
rewritten in other languages such as Java and extended to three dimensional
systems straightforwardly. We illustrate the usefulness of our analysis with
implementations of spin-films (the two-dimensional XY model with and without an
external magnetic field) and a model for diffusion through a triangular
lattice.Comment: 12 pages, 10 figure
What May Visualization Processes Optimize?
In this paper, we present an abstract model of visualization and inference
processes and describe an information-theoretic measure for optimizing such
processes. In order to obtain such an abstraction, we first examined six
classes of workflows in data analysis and visualization, and identified four
levels of typical visualization components, namely disseminative,
observational, analytical and model-developmental visualization. We noticed a
common phenomenon at different levels of visualization, that is, the
transformation of data spaces (referred to as alphabets) usually corresponds to
the reduction of maximal entropy along a workflow. Based on this observation,
we establish an information-theoretic measure of cost-benefit ratio that may be
used as a cost function for optimizing a data visualization process. To
demonstrate the validity of this measure, we examined a number of successful
visualization processes in the literature, and showed that the
information-theoretic measure can mathematically explain the advantages of such
processes over possible alternatives.Comment: 10 page
The Need to Support of Data Flow Graph Visualization of Forensic Lucid Programs, Forensic Evidence, and their Evaluation by GIPSY
Lucid programs are data-flow programs and can be visually represented as data
flow graphs (DFGs) and composed visually. Forensic Lucid, a Lucid dialect, is a
language to specify and reason about cyberforensic cases. It includes the
encoding of the evidence (representing the context of evaluation) and the crime
scene modeling in order to validate claims against the model and perform event
reconstruction, potentially within large swaths of digital evidence. To aid
investigators to model the scene and evaluate it, instead of typing a Forensic
Lucid program, we propose to expand the design and implementation of the Lucid
DFG programming onto Forensic Lucid case modeling and specification to enhance
the usability of the language and the system and its behavior. We briefly
discuss the related work on visual programming an DFG modeling in an attempt to
define and select one approach or a composition of approaches for Forensic
Lucid based on various criteria such as previous implementation, wide use,
formal backing in terms of semantics and translation. In the end, we solicit
the readers' constructive, opinions, feedback, comments, and recommendations
within the context of this short discussion.Comment: 11 pages, 7 figures, index; extended abstract presented at VizSec'10
at http://www.vizsec2010.org/posters ; short paper accepted at PST'1
Taming Numbers and Durations in the Model Checking Integrated Planning System
The Model Checking Integrated Planning System (MIPS) is a temporal least
commitment heuristic search planner based on a flexible object-oriented
workbench architecture. Its design clearly separates explicit and symbolic
directed exploration algorithms from the set of on-line and off-line computed
estimates and associated data structures. MIPS has shown distinguished
performance in the last two international planning competitions. In the last
event the description language was extended from pure propositional planning to
include numerical state variables, action durations, and plan quality objective
functions. Plans were no longer sequences of actions but time-stamped
schedules. As a participant of the fully automated track of the competition,
MIPS has proven to be a general system; in each track and every benchmark
domain it efficiently computed plans of remarkable quality. This article
introduces and analyzes the most important algorithmic novelties that were
necessary to tackle the new layers of expressiveness in the benchmark problems
and to achieve a high level of performance. The extensions include critical
path analysis of sequentially generated plans to generate corresponding optimal
parallel plans. The linear time algorithm to compute the parallel plan bypasses
known NP hardness results for partial ordering by scheduling plans with respect
to the set of actions and the imposed precedence relations. The efficiency of
this algorithm also allows us to improve the exploration guidance: for each
encountered planning state the corresponding approximate sequential plan is
scheduled. One major strength of MIPS is its static analysis phase that grounds
and simplifies parameterized predicates, functions and operators, that infers
knowledge to minimize the state description length, and that detects domain
object symmetries. The latter aspect is analyzed in detail. MIPS has been
developed to serve as a complete and optimal state space planner, with
admissible estimates, exploration engines and branching cuts. In the
competition version, however, certain performance compromises had to be made,
including floating point arithmetic, weighted heuristic search exploration
according to an inadmissible estimate and parameterized optimization
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