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

A Development Environment for Visual Physics Analysis

The Visual Physics Analysis (VISPA) project integrates different aspects of physics analyses into a graphical development environment. It addresses the typical development cycle of (re-)designing, executing and verifying an analysis. The project provides an extendable plug-in mechanism and includes plug-ins for designing the analysis flow, for running the analysis on batch systems, and for browsing the data content. The corresponding plug-ins are based on an object-oriented toolkit for modular data analysis. We introduce the main concepts of the project, describe the technical realization and demonstrate the functionality in example applications

Multi-Media Mail in heterogeneous Networks

The MIME approach seems to be the most reasonable effort for allowing the sending and receiving of multimedia messages using standard Internet mail transport facilities. Providing new header fields, such as MIME-Version, Content-Type, and Content- Transfer-Encoding, it is now possible to include various kinds of information types, e.g. audio, images, richtext, or video, into a RFC 822-conformant mail. Making use of these headers, it is possible to fully describe an attached body part, so that a receiving mail user agent is able to display it without any loss of information. Additionally, the definition of the "multipart" and "message" content types allows the creation of hierarchical structured mails, e.g. a message containing two alternative parts of information, one that can be shown using a simple ASCII-terminal, the other to be displayed on a multimedia workstation. Allowing the definition of bilaterally defined content types and providing a standardized means of establishing new content types prevent MIME from being a one-way road and supply mechanisms to extend MIME for future use

FAST: A multi-processed environment for visualization of computational fluid dynamics

Three-dimensional, unsteady, multi-zoned fluid dynamics simulations over full scale aircraft are typical of the problems being investigated at NASA Ames' Numerical Aerodynamic Simulation (NAS) facility on CRAY2 and CRAY-YMP supercomputers. With multiple processor workstations available in the 10-30 Mflop range, we feel that these new developments in scientific computing warrant a new approach to the design and implementation of analysis tools. These larger, more complex problems create a need for new visualization techniques not possible with the existing software or systems available as of this writing. The visualization techniques will change as the supercomputing environment, and hence the scientific methods employed, evolves even further. The Flow Analysis Software Toolkit (FAST), an implementation of a software system for fluid mechanics analysis, is discussed

Evaluation of a Simple DC-Balanced Encoding Method for LVDS Data Transmission Over CAT-5 Cable

In this study, a simple dc-balanced encoding scheme was developed to reduce the bit error rate for high-speed data transmission over CAT-5 cable using Low-voltage Differential Signaling (LVDS). The dc balance encoder was implemented to make binary sequences with a spectral null at zero. A data transmission controller using the dc balanced scheme was implemented in an Altera Field Programmable Gate Array (FPGA), including data generators that send data to a DS92LV1023 10-bit bus LVDS serializer, data checkers for checking the data coming from a DS92LV1224 10-bit bus LVDS deserializer, and dc balance and non-dc balance encoders. Data was transmitted over various lengths of CAT-5 cable with and without dc balance to determine the effect of the dc balance scheme on transmission errors. To generalize the type of data used in the transmission tests, three different kinds were selected for the error testing: pseudo-random numbers generated by a 32-bit Linear Feedback Shift Register (LFSR) binary polynomial generator; consecutive numbers generated by a counter; and data looked-up from a Read Only Memory (ROM) implemented in an FPGA embedded memory block. The data transmission controller was constructed, configured, and tested both with and without dc balance. It provides a data transmission rate of 538.8 Mbps, and is able to send the number of errors encountered during the transmission process to a PC via the PCI bus. Testing results verify that the dc balance scheme adopted in this thesis significantly improves the accuracy of the serial data transmission. Both dc-balanced and non-dc-balanced encoding proved error-free out to cable lengths of about 19.8 meters. DC-balanced encoding also extended the error-free cable length by about 1.5 meters and reduced errors by about 60% for longer cables

REACLIBaLIVe! (REACLIB Rate Library Interactive Viewer): A Software Package for Graphical Analysis of Nuclear Reaction Rates for Astrophysics

Nucleosynthesis occurs in such diverse astrophysical phenomena as ordinary stars, like our own Sun, supernovae, novae, X-ray bursts, and the Big Bang. Large sets of nuclear reaction rates for hundreds of seed isotopes are utilized in simulations of these nucleosynthesis processes. A cross-platform, Java software package called REACLIB aLIVe! has been developed with intuitive graphical interfaces and interactive controls to produce custom one-dimensional plots of reaction rates. The points used for these plots are calculated from exponential fits whose parameters, along with other quantities, make up the REACLIB Nuclear Reaction Rate Library. The software offers nuclear astrophysicists the capability to rapidly display any of 8000 nuclear reactions in the library, as well as to add new reaction rates and compare them to ones in the library. The plots produced by the software may be exported in the postscript format, which is easily edited and incorporated into papers, presentations, and websites. The software is available over the World Wide Web or as a downloadable Java archive file

The GEANT4 Object Oriented Simulation Tookit

Geant4 is a toolkit for the simulation of the passage of particles through matter, developed with advanced software engineering techniques. Its application areas include high energy and nuclear physics experiments, space physics, $9 medical physics and radiation background studies