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This project is funded through the JISC New Technologies Initiative at Loughborough University and dovetails with AGOCG's other activities in the areas of graphics and visualization. The take-up for the output has been good and the first 3 reports are included in the first mailing. These are:
If you have not subscribed and want more information on doing so, please contact me.
A workshop on the topic of WWW - a Strategic Tool for Higher Education is being organised as part of the SIMA project. This will be a 2 day event in February and will provide a briefing for information managers on the first day and will be followed by discussions to develop guidelines and advice to information managers and to funding bodies. The workshop will recommend projects to be part of SIMA for the following year. Numbers on both days will be limited and anyone interested should email me for details. A full report will be produced by AGOCG and will be available in both paper and on-line forms.
A series of case studies in the use of IT in art and design is being put together. A total of 18 case studies are being written and will be published as AGOCG Technical Report 26 during December. If you would like a copy please email Joanne Barradell j.t.barradell@lut.ac.uk or write to me.
I am also trying to gather information about software used in art and design with the aim of working with the community and with CHEST to get some software licence agreements. If you have any information along these lines or ideas on what we should be looking at please let me know.
I have been involved in the programme for the Universities and Colleges Software Group's Workshop on the theme of Collaborating Across the Network being held on 4th and 5th January 1995. Some of the projects funded through the AGOCG New Technologies Initiative project will be reporting. There will also be information about other JISC activities.
Don't forget that AGOCG are now on the Web at: http://www.agocg.ac.uk:8080/agocg/.
Some information gleaned from the various CHEST mailing recently which might be of interest.
Manchester is now in a position to distribute Micrografx Designer 4.1. The standard media for this upgrade is CD Rom (Cost 25.00), and this will include the full clipart library of 10,000 pieces. This version carries an extensive on-line help facility and it is thought unlikely that sites will require printed documentation. However this will be made available in due course.
Origin was one of the products recommended for a site licence deal when the UCSG's Graphics Working Party reviewed technical graphics packages. CHEST are working on a software agreement for this product.
CHEST are currently looking at various publishing and delivery packages. They have been collecting information on various products including Word Perfect's Envoy, Interleaf's product and Acrobat. If you have any views on these products and what the community should be doing in this area please contact CHEST.
If you have any views on what products CHEST should be looking you can mail these to: chest-wishlist@mailbase.ac.uk and join the list for subsequent discussions.
A while ago I wrote an article listing the various locations of Frequently Asked Questions for a number of visualization systems. This short article adds to that information by providing references to WWW sites for each visualization system. These pages also hold references to other useful Weblets on the network:
If you have questions, comments or queries about information held on the WWW servers listed above then you will find the appropriate contact email addresses listed on each home page.
Selecting graphics software to satisfy a particular presentational task can be a daunting business. The range of packages available, particularly on microcomputer systems, presents a potentially bewildering choice. The lack of any standard, de facto or otherwise, for presentation graphics means that it is not possible to decide easily whether or not a particular package will produce the sort of picture type that you require for your work. The package documentation has to be examined and, often, experts in the use of the package consulted, to determine if a particular type of diagram or image can be produced. Again, a package may produce the type of picture that you require, but may not be capable of outputting it to the sort of device that you wish to use. In general, a great deal of time and effort may have to be expended before you can be satisfied that a particular package will fulfil your needs.
A document to help speed up the package selection process, entitled Selecting a Package for Graphics Presentation, has been produced by Computing Services at the University of Edinburgh, with support from AGOCG. The document works by distilling the characteristics of graphics presentation requirements into a matrix of facilities which can be interrogated to find a suitable candidate item of software. The document also looks in some detail at the anatomy of various types of chart and provides examples of those charts in common use within the University for research or educational purposes. The reader can then make use of the old adage that a picture is worth a thousand words, by picking out the sort of chart or diagram of interest and then checking to see which of the software packages can be used to produce it. Sections on graphics file formats and graphics output devices are also included.
The document is principally intended to help users and user support staff find their way through the maze of graphics software. The packages described in the matrix are ones which are generally popular throughout the HE sector and include: Access, Corel Chart, Corel Draw, Cricket Graph, Cricket Presents, Designer, Micrografx Draw!, Excel, Fig-P, Harvard Graphics, Illustrator, MacDraw PRO, Mintab, MSWorks, Origin, Paradox, Persuasion, Powerpoint, Quattro Pro, SlideWrite, SPSS, Systat, UniEdit, UniGraph, UniMap, Word and Wordperfect.
Machine readable postscript copies of the document can be obtained via anonymous ftp from the FTP server unix.hensa.ac.uk in the directory /pub/misc/agocg/documentation in compressed tar format and in a subdirectory /pub/misc/agocg/documentation/micros in ZIP format. The index file gives details of the contents.
Steve Benford, John Boyle, Richard Cooper, Jessie Kennedy, John Mariani, Tom Rodden.
A group of independent researchers in the field of database visualization have come together to collaborate and exchange ideas. The group is mainly interested in the use of 3D animated graphics to aid users when interacting with database management systems. A number of systems have been developed which use 3D graphical user interfaces for database access. It is felt that three dimensional graphics can offer usability and expressive power for database interfaces, which is lacking in 2D interfaces.
Database technology has made it possible to model and store real world data in a comprehensive manner. This data can then be manipulated, updated, or queried by a user. However most such manipulations have to be done through a rigid and unforgiving syntactical language such as SQL. It is hardly surprising that work on designing user interfaces to databases has been going on for over 20 years - but still the interfaces for database management systems do not offer the user the power to interact with the actual data in an easy manner. This is mainly due to the limitations of the 'desktop metaphor' - when attempting to deal with such abstractions as constructing queries and visualizing results a more powerful expressive system is needed. Interfaces to databases usually come in one of two forms: database schema or table based. A schema is an abstract representation of the real world data. This schema can be used by the designer as the basis of the 0 interface (GUIDE). An alternative metaphor when constructing interfaces to databases is to use a diagrammatic picture of a relation table - where the user fills in columns to define the query - this approach was first suggests by M Zloof (QBE) in 1974 and is still used today in a number of popular systems (Dbase (Borland), Paradox (Borland) and Access (Microsoft)).
Both of these types of interface lack any powerful visual techniques to guide the user when examining the results or forming the query.
Three dimensional graphics can be used to visualize the whole process of querying, data examination and data retrieval from a database. A number of independent research groups inside the United Kingdom have all found limitations with using flat two dimensional displays, and so have begun experimenting with 3D interactive animated visualizations. These visualizations are designed to aid the user in the querying process.
Three different systems have been built:
Each of these systems builds upon the same idea, and that is of being able to visualize the database in some abstract manner. They attempt to give the user more than just a means of querying the database, they provide the user a visual reference through which they can enter into a dialogue with the database.
Future work is planned in both a collaborative and individual manner. Most of the work to date has been in testing the feasibility of using 3D graphics as an effective medium in helping the user describe the query they wish to perform, and to allow the user to browse through a visualization of results.
The next stage involves four avenues of enquiry:
The SIG is interested in visualizing database and the operations the user wishes to perform on it. So far the group has addressed visualization of:
The strength of the group is that while all the researchers worked independently, they all concluded that when interacting with a database, a visual approach was needed. They have now come together with a common goal in mind: to build a new generation of user interfaces that will take database access out of the hands of the select few and place it in the hands of the non-specialist user.
NISS has recently been looking at remote viewing of PostScript documents using GhostView and GhostScript to X servers, in particular Xsun from the MIT version of X11R5 and eXceed from Hummingbird Communications. X11R6 is not expected to directly make a great deal of difference to this, but the X Remote work in progress wiil do. They have identified a number of changes which can speed this up, particularly in the start- up time. A simple (8 line) patch to Ghostscript 2.6.1 can reduce the amount of traffic generated by up to 33% although the normal reduction is a lot less than this. Use of the -monochrome switch to Ghostview reduces the amount of traffic needed to set up the display by 16kbytes. If the document is only monochrome this is wasted. Standard techniques such as reducing the number of fonts which have to be loaded are also worthwhile.
X goes to great length to make access to the hardware support for colour on the X server as device independent as possible. However this independence is not without cost. When ghostscript starts it attempts to allocate a number of colours. The number depends on the hardware, but is typically 123 (53-2) on a colour display, this being 532. This allows for 5 bits for each of Red, Green and Blue, and assumes that colours for black and white have already been allocated. As each colour request requires 16 bytes to request, and 32 bytes to acknowledge, this colour setup requires the transfer of nearly 6,000 bytes. It is wasted if the document only requires monochrome! Worse still is that each acknowledgement is needed before the next request can be made, so each of these requests and acknowledgements travels in a separate TCP lIP packet, adding nearly another 10,000 bytes of overhead if standard headers are used. This takes about 2 seconds to transmit on a 64kbps line. A better solution would be to delay allocating the colours until either the first use, or better still until each of the 123 extra colours is required. This would retain the flexibility of the current scheme with no penalty for documents which do not require it.
X enables advanced users to customise their environment to a very high degree. In the case of ghostscript, this complexity caused an additional problem. It was decided to use the Xt toolkit to parse the database - a sensible choice. However unfortunately the code to do this parsing left a great deal to be desired. If the unidiff in the Figure is applied to the file gdevxini.c it will improve the code significantly. This is not the best code, but is the minimal change. If an up-to-date version of the patch program which understands unidiff format patches, then it can be applied by hand. All that is needed is to add the lines which start with a + sign in the correct place (around lines 300 to 320) but obviously without the + sign (see figure).
In the standard applications defaults for ghostview, it uses two fonts: -adobe-newcentury schoolbook-medium-r-normal-- *140-*-*-p-*-is08859-1 and -adobecourier-medium-r-normal--*-140 **-m-*-is08859-1 in addition to the cursor font. Normally it only uses the second of these. If these fonts are not already loaded, then information about them has to be down-loaded. This can be avoided by specifying alternative fonts in the X resource database.
Figure: Patch to avoid double-read of X resource database
@@ -301,15 +301,24 @@
/* Get X Resources. Use the toolkit for this. */
XtToolkitInitializeO;
app _con =XtCreateApplicationContextO;
+#ifdef READ_TWICE
+ /* Read the environment a second time */
dpy = XtOpenDisplay(app_con, NULL, "ghostscript", "Ghostscript",
NULL, 0, &zero, NULL);
+#else
+ XtDisplayinitialize(app_con, xdev->dpy, "ghostscript", "Ghostscript"
+ NULL, 0, &zero, NULL);
+ dpy = xdev->dpy;
+#endif
top level = XtAppCreateShell(NULL, "Ghostscript",
applicationShellWidgetClass, dpy, NULL, 0);
XtGetApplicationResources(toplevel, (XtPointer) xdev,
resources, XtNumber(resources), NULL, 0);
XtDestroyWidget( top level) ;
+#ifdef READ_TWICE
XtCloseDisplay(dpy);
XtDestroy ApplicationContext( app _con);
+#endif
gdev_x_setup_colors(xdev);
gdev_x_setup_fontmap(xdev);
A typical set of timings for eXceed, running on both a 486DX33 and a 486DX266 connected over a local ethernet, both with and without the -monochrome_switch_are
| Type | DX33 | DX266 |
|---|---|---|
| normal | 5.4 | 4.2 |
| -monochrome | 4.0 | 3.4 |
| speedup (%) | 26 | 19 |
A text and PostScript version of this document, and a text version of the patch file are available from the directory: /NISS/Postscript on the host: ftp.niss.ac.uk.
Regular readers of G&V will need no reminding about AGOCG Library but there may be one or two new readers at this time of year who are unaware of its existence. The project was set up to try to capture all those hard-to-get computer-generated graphics. We now have over 250 animation clips which can be borrowed to illustrate various techniques and results. The index to the clips runs to over 30 pages when printed so only a few sample entries (from a search for entries with the string visual) are re-produced below to whet your appetite. The full index is available in the file index.tx associated with the agocg-resources list on mailbase.
Rendering surface-particles, Produced By Netherlands Energy Research Foundation ECN, Credits: Dr Jarke van Wijk, Running Time 00:05:03, Tools: custom software, Sun Sparcstation IPC
A voxel-based forward projection algorithm for rendering surface and volumetric data , Produced By Hughes Training Inc, Credits: John Wright, Julia Hsieh, Running Time 00:05:08
Flow visualization as a basic tool to investigate the dynamics and topology of jets, Produced By Naval Research Laboratory, Credits: Fernando Grinstein, U.R. Obeysekare, G. Patanaik, Running Time 00:05:29, Tools: ray tracing technique, AVS software
Using VIS-AD to visualize a cloud discrimination algorithm, Produced By William Hibbard, Credits: authors: William Hibbard, Charles Dyer, Brian Paul, Running Time 00:05:03, Tools: VIS-AD software; SGI 340, VGX hardware
Oceanography: visualization of sea floor structures through gravitational acceleration, Produced By San Diego Supercomputer Center, Credits: James J. McLeod, Running Time 00:03:27, Tools: Wavefront TAV; SDSC data translation code; SGI 4D/320 VGX
Visualization of high resolution three-dimensional nonlinear finite element element analysis: sand technology in DYNA 3D, Produced By LLNL, Credits: Mark Christon Thomas Spelce, Running Time 00:02:46, Tools: SGI 4D/35; Video Framer; L VR/ L VS-5000; home grown software
Interactive visualization of large scalar voxel fields, Produced By Fraunhofer Institute fuer Graphische Datenverarbeitung, Credits: Georgios Sakas Jochen Hartig, Running Time 00:05: 10, Tools: InViVo rendering system developed by FhG-IGD; SGI 4D/ 380 VGX
Global climate visualization, Produced By LLNL. Credits: R. Crawfis, N. Max, G. Cronshagen, C. Anderson D. Williams. Running Time 00:05:23. Tools: custom software
This conference is the first time the ACM (Association of Computing Machinery) have held a multimedia conference as a stand-alone event Multimedia '93 was held in conjunction with SIGGRAPH. There were around 1000 attendees including participants from the UK, Switzerland, France, Holland, Canada, Japan and the US. Papers were presented by authors from both academia and industry. The conference was preceded by two days of courses, covering a variety of topics from Game Design for Marketing and Training to Singularity Modeling for Abstracting Multimedia Data. The conference itself consisted of two parallel tracks of sessions in which 50 papers were presented and a separate track of panel discussions. There were a number of demonstrations during the conference, including a demonstration of Multimedia Teleconferencing on the Internet Multicast Backbone (MBONE). Several sessions, including the opening plenary panel, were broadcast over MBONE to the World Wide Web conference in Chicago. There was a small exhibition area where companies including IBM and Kaleida were showing their latest products. The Ubiquitous Art Zone allowed multimedia artists to display their creations ranging from immersive environments interactive CD ROMs.
Designing a Senior Level or Graduate Course in Interactive Multimedia: Rachelle Heller, George Washington University Linda Kieffer, Eastern Washington University.
This half day course was aimed mainly at people who would be teaching a course about multimedia to undergraduates from a range of disciplines. The speakers presented ideas based on their own syllabi and provided sample syllabi from other universities. They felt the best way to organize a course on multimedia was to look at the separate components individually i.e. text, graphics, sound and video before letting the students try to combine them into a multimedia presentation. They stressed that unless the students had a good grasp of each component, what it can be used for, how it is generated, stored etc., they would be unable to make good use of it. In their courses other departments also contribute, for example a lecturer from the Music Department talks about the evocative value of sound. Much of the work in their courses, including the final projects to produce a multimedia presentation, is done in groups. This allows students to exchange ideas and is particularly useful with a mixed group of students, where some may be good programmers and other good artists, for example.
In the final part of the course they described the kind of multimedia labs they had setup (PC and Mac), and explained the trade-offs they made between the hardware they wanted and what they could afford. They felt one of the most important considerations was memory. Finally, ancillary topics such as copyright law and marketing and distribution were mentioned, and the authors gave descriptions of some text books they had found useful.
Towards Usability Guidelines for Multimedia Systems: M Bearne, S Jones, J Sapsford-Francis, School of Information Sciences, University of Hertfordshire.
This paper aimed to provide some guidelines to help designers produce better multimedia applications by examining the users' attentional capabilities. The main points they found were:
Currently multimedia designers must make decisions about usability largely based on intuition and common sense. The authors' future aim is to make these decisions easier by investigating toolbased support for usability guidelines.
PREMO: An ISO Standard for Presentation Environment for Multimedia Objects: I Herman, G S Carson, J Davy, DA Duce, PJW ten Hagen, W T Hewitt, K Kansy, B J Lurvey, R Puk, G J Reynolds, H Stenzel
This paper gave an overview of PREMO and was presented by W T Hewitt, University of Manchester. The PREMO project was started in October 1992 and the work was approved by ISO/IEC JTC1 in February 1994. PREMO differs from other multimedia standards in that it concentrates on presentation techniques.
PREMO uses object-oriented techniques, as they have already proven their values in using inheritance as a tool for extensibility. Distributed environments are now widespread and multimedia applications often exploit their advantages. Since defining complete object-oriented systems for use in a distributed environment would go far beyond the scope of the PREMO working group, the PREMO specification will make use of techniques already developed elsewhere.
The conceptual framework for PREMO consists of an abstract object model and the notion of components which contain and organise the PREMO functionality needed to address specific problem areas. The object model is based on subtyping and inheritance. The notion of non-objects is also included, of which events are a special category. A component is a collection of objects and non-object types. All components inherit from a Foundation Component.
The initial PREMO standard will: define the exact conceptual framework for multimedia presentation; define rules for components, their interrelationships, inheritance, conformance rules, etc; include the specification of the Foundation Component; include the specification of some other components, namely:
More components will be added in the future.
PREMO is expected to become a Draft International Standard in June 1996, and an International Standard in June 1997.
The Influence of Multimedia on Learning: A Cognitive Study A Large, J Beheshti, A Breuleux, A Renaud McGill Univeristy, Canada.
This paper looked at the assumption that the addition of still images, animation and sound to text will enhance any information product. The researchers tested the understanding of grade-six primary (11 years) school children on articles presented to them as printed text, text on a computer screen, and text animation and images. They used the commercial available CD-ROM Compton's Multimedia Encyclopaedia and specially generated multimedia sequences.
They found that multimedia did improve some types of learning. If the students were merely required to memorise the text, then text alone worked as well as multimedia. However, multimedia seemed to help the children understand the underlying principles and deeper comprehension. Multimedia seemed to be best suited to procedural articles or where the children were asked to extract the main themes of an article.
The proceedings of this conference are available in both hard copy and on CD-ROM. The CD-ROM also contains movie clips in Quicktime and MPEG formats. Some of the clips are supporting papers, some from the conference video and other clips from exhibits in the Ubiquitous Art Zone. The conference video is available in NTSC format only.
Visualization '94 is the fifth conference in a series devoted to data visualization. The conference is sponsored by the IEEE Technical Committee on Computer Graphics in cooperation with ACM SIGGRAPH. This year the conference attracted over 450 international visualization users and researchers. The format of the conference involved a number of tutorials, panels, case studies, demonstrations and over 40 refereed technical papers. The proceedings from the conference consist of the technical papers and case studies (450 pages including 45 pages of colour plates), two video tapes with sequences to supplement the papers and a CD which contains the conference proceedings in AdobeAcrobat format. More details on how to obtain these can be found at the end of this article.
Over the first three days the conference held a number of tutorials which included Volume visualization algorithms and applications, Multi-dimensional geometry and multi-variate problems and Analysis and processing of environmental datasets. The volume visualization tutorial was presented by three prominent researchers in this field over the past fifteen years: Arie Kaufman, Bill Lorenson and Roni Yagel. The tutorial covered basic nomenclature, surface extraction, volume shading and synthesis with the tutorial notes providing a good source of references for researchers relatively new to this field. The tutorial covering multivariate problems described a number of techniques and very clearly illustrated their use with a number of real world applications. These included the analysis of complex systems such as gold prices over the previous seven years with respect to eight other stock market variables, disease spread throughout honey bees in Switzerland, a model of the Peruvian economy and conflict resolution for air traffic controllers.
The co-chair Nahum Geshon opened the main conference and welcomed participants. This year's opening address was given by Gregory C Simon, the Chief Domestic Policy Advisor to Vice President Al Gore. Histalk was entitled "The Idea of Information: The Gene in the Machine" and was concerned with how computer systems and other forms of digital storage are converging with natural information systems such as DNA genetic encoding. He concluded by suggesting in the future biological and machine-like principles will be used together to optimize new, complex artificial and natural organisms. The perfectly executed talk made use of a plethora of media presentation techniques including mosaics of still images, computer animations, live video sequences and carefully chosen audio clips bound together using the Silicon Graphics tool Showcase.
During questions Mr Simon also revealed that in addition to email access to the Whitehouse they would also be accessible via the World Wide Web (http://www.whitehouse.gov) and would use this to disseminate certain policy documents to the community.
The honorary chair address was presented by Professor Andries van Dam, Brown University, US, titled Interactive Visualization via 3D User Interfaces. This superb presentation addressed some of the deficiencies in traditional 2D widgets for interacting with visualization environments and use in virtual reality. The talk covered direct manipulation and 3D widgets for control of 3D interfaces and previewed some work that had been undertaken to develop a tool box that allowed the creation and definition of 3D widgets and their associated interaction. Some of their work, sponsored by the NASA Ames Virtual Wind Tunnel project, illustrated these techniques in use. This also included a method of using a computer representation of smoke rings to visualize flow fields.
The prize for the best paper was shared this year between Visualizing Flow over Curvilinear Grid Surfaces using Line Integral Convolution, L K Forsell, NASA Ames Research Center and The Topology of Symmetric, Second-Order Tensor Fields, T Delmarcelle and L Hesselink, Stanford University. The first paper extended the Line Integral Convolution (LIC) technique for imaging and animating vector fields which was first introduced by Cabral and Leedom. The extensions were for flow over parametric surfaces specifically curvilinear grids, to cater for misleading aspects when animating over curvilinear grids and a technique to visualize vector magnitude as well as direction. The second paper presented a study of symmetric, second-order tensor fields with the goal of representing their structure by extending ideas in vector field topology. This involved identifying two forms of degenerate points that could be combined to form more familiar singularities such as saddle, nodes, centres or foci. The paper also presented a topological rule that extended to tensor fields the Poincare-Hopf theorem for vector fields.
The best case study award was given to Visualization of 3D Ultrasonic Data G Sakas, L A Schreyer, M Grimm, Fraunhofer Institute for Computer Graphics, Darmstadt, Germany. Ultrasound is a popular non-invasive, nonradioactive tomographic technique but producing 3D representations from the data is not particularly easy due to the noisy, fuzzy nature of the ultrasound images. The paper detailed a number of filtering techniques that have been used to improve the data along with some semi-automatic segmentation tools to isolate interesting features from the images. The study also presented their improved surface extraction procedures to allow high quality images to be produced in a few seconds on a standard workstation thus making its use suitable for routine clinical applications.
On 14 November the Central Computing and Informatics Departments at the Rutherford Appleton Laboratory were merged to form a new Computing and Information Systems Department (CISD).
Creating the new Department has brought together a wide range of IT and computational skills in R&D and service-related disciplines into a single, comprehensive organisation that will increase the breadth and scope of work with customers and partners as the role and status of the Laboratory begin to change during the next year.
The Mission Statement for CISD is To provide high quality computational facilities, specialist services and high value IT solutions for customers inside and outside DRAL.
G&V will continue to be published according to the regular schedule, 6 times per year, targeting its normal readership. The Editorial team remains unchanged.