49,134 research outputs found
Instrumentation, performance visualization, and debugging tools for multiprocessors
The need for computing power has forced a migration from serial computation on a single processor to parallel processing on multiprocessor architectures. However, without effective means to monitor (and visualize) program execution, debugging, and tuning parallel programs becomes intractably difficult as program complexity increases with the number of processors. Research on performance evaluation tools for multiprocessors is being carried out at ARC. Besides investigating new techniques for instrumenting, monitoring, and presenting the state of parallel program execution in a coherent and user-friendly manner, prototypes of software tools are being incorporated into the run-time environments of various hardware testbeds to evaluate their impact on user productivity. Our current tool set, the Ames Instrumentation Systems (AIMS), incorporates features from various software systems developed in academia and industry. The execution of FORTRAN programs on the Intel iPSC/860 can be automatically instrumented and monitored. Performance data collected in this manner can be displayed graphically on workstations supporting X-Windows. We have successfully compared various parallel algorithms for computational fluid dynamics (CFD) applications in collaboration with scientists from the Numerical Aerodynamic Simulation Systems Division. By performing these comparisons, we show that performance monitors and debuggers such as AIMS are practical and can illuminate the complex dynamics that occur within parallel programs
Tools for Search Tree Visualization: The APT Tool
The control part of the execution of a constraint logic program can be conceptually shown as a search-tree, where nodes correspond to calis, and whose branches represent conjunctions and disjunctions. This tree represents the search space traversed by the program, and has also a direct
relationship with the amount of work performed by the program. The nodes of the tree can be used to display information regarding the state and origin of instantiation of the variables involved in each cali. This depiction can also be used for the enumeration process. These are the features implemented in APT, a tool which runs constraint logic programs while depicting a (modified) search-tree, keeping at the same time information about the state of the variables at every moment in the execution. This information can be used to replay the execution at will, both forwards and backwards in time. These views can be abstracted when the size of the execution requires it. The search-tree view is used as a framework onto which constraint-level visualizations (such as those presented in the following chapter) can be attached
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
ROOT - A C++ Framework for Petabyte Data Storage, Statistical Analysis and Visualization
ROOT is an object-oriented C++ framework conceived in the high-energy physics
(HEP) community, designed for storing and analyzing petabytes of data in an
efficient way. Any instance of a C++ class can be stored into a ROOT file in a
machine-independent compressed binary format. In ROOT the TTree object
container is optimized for statistical data analysis over very large data sets
by using vertical data storage techniques. These containers can span a large
number of files on local disks, the web, or a number of different shared file
systems. In order to analyze this data, the user can chose out of a wide set of
mathematical and statistical functions, including linear algebra classes,
numerical algorithms such as integration and minimization, and various methods
for performing regression analysis (fitting). In particular, ROOT offers
packages for complex data modeling and fitting, as well as multivariate
classification based on machine learning techniques. A central piece in these
analysis tools are the histogram classes which provide binning of one- and
multi-dimensional data. Results can be saved in high-quality graphical formats
like Postscript and PDF or in bitmap formats like JPG or GIF. The result can
also be stored into ROOT macros that allow a full recreation and rework of the
graphics. Users typically create their analysis macros step by step, making use
of the interactive C++ interpreter CINT, while running over small data samples.
Once the development is finished, they can run these macros at full compiled
speed over large data sets, using on-the-fly compilation, or by creating a
stand-alone batch program. Finally, if processing farms are available, the user
can reduce the execution time of intrinsically parallel tasks - e.g. data
mining in HEP - by using PROOF, which will take care of optimally distributing
the work over the available resources in a transparent way
Visualization designs for constraint logic programming
We address the design and implementation of visual paradigms for observing the execution of constraint logic programs, aiming at debugging, tuning and optimization, and teaching. We focus on the display of data in CLP executions, where representation for constrained variables and for the constrains themselves are seeked. Two tools, VIFID and TRIFID, exemplifying the devised depictions, have been implemented, and are used to showcase the usefulness of the visualizations developed
Simulation System for the Wendelstein 7-X Safety Control System
The Wendelstein 7-X (W7-X) Safety Instrumented System (SIS) ensures personal
safety and investment protection. The development and implementation of the SIS
are based on the international safety standard for the process industry sector,
IEC 61511. The SIS exhibits a distributed and hierarchical organized
architecture consisting of a central Safety System (cSS) on the top and many
local Safety Systems (lSS) at the bottom. Each technical component or
diagnostic system potentially hazardous for the staff or for the device is
equipped with an lSS. The cSS is part of the central control system of W7-X.
Whereas the lSSs are responsible for the safety of each individual component,
the cSS ensures safety of the whole W7-X device. For every operation phase of
the W7-X experiment hard- and software updates for the SIS are mandatory. New
components with additional lSS functionality and additional safety signals have
to be integrated. Already established safety functions must be adapted and new
safety functions have to be integrated into the cSS. Finally, the safety
programs of the central and local safety systems have to be verified for every
development stage and validated against the safety requirement specification.
This contribution focuses on the application of a model based simulation system
for the whole SIS of W7-X. A brief introduction into the development process of
the SIS and its technical realization will be give followed by a description of
the design and implementation of the SIS simulation system using the framework
SIMIT (Siemens). Finally, first application experiences of this simulation
system for the preparation of the SIS for the upcoming operation phase OP 1.2b
of W7-X will be discussed
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