- referencing Books: [Goll (99)] Goll, J.: "The Guide to Hyper-G"; Springer,
Heidelberg / New York (1999)

- referencing Journals: [Wonko and Tsio 99b] Wonko, A. C., Tsio, F.: "Extended Use of Hyperlinks"; J.UCS (Journal for Universal Computer Science), 5, 3 (1999), 225-327.
The form 5, 3 (1999) indicates volume number 5, issue number 3 1999. 225-327 indicate the page numbering.

- referencing Proceedings: [Tsio 99a] Tsio, F.: "Hypermedia Systems in the Future"; Proc. Ed-MEDIA'99, AACE Publishing, Vancouver (1999), 115-123.

- referencing Reports: [Mollester, Goll 99c] Mollester, K., Goll, J.: "Information Landscapes and their Advantages in Large Hypermedia Systems"; IIG Report 998, Graz, Austria (1999), also appeared as electronic version, anonymous FTP autnet.org, in publications/June-99-online.

2.4.3 Figures:

2.4.4 Tables:

2.4.5 Footnotes:

Example: _________________________________ [1] as we mentioned earlier this is how to write footnotes

3 Accepted File Formats

You should not have problems generating a file in one of those formats, no matter which wordprocessor you are using. When submitting a file, please follow the rules given below, allowing us to be able to read and convert your article.

3.1 PostScript

MS-Windows Users: We tested all PS Printer Drivers available to us, and they all worked. But be careful when configuring your printer driver

- There MUST be a PS Header sent with the printing job. - You MUST use the substitution table for fonts and and you MUST enter "download font" for every font used in the document. DVIPS users: No problems were detected, the only thing is that you MUST NOT use the M option.

If you want to make sure that the document you submit is in the correct format, you may try, whether ghostscript (or ghostview) can correctly deal with it, since ghostscript is the kernel of our conversion software. Ghostscript is a PostScript Interpreter available on many ftp servers worldwide for various platforms including most of the UNIX derivates, MS-Windows, OS/2 and Windows-NT. You may also submit a testfile (e.g. the first page of the paper) as email to JUCS@iicm.tu-graz.ac.at with the Subject [testfile]. We will test its compatibility to our conversion software and send you an email about the test result.

3.2 RTF

3.3 LaTeX If you use a special LaTeX style file, please submit it together with your article. We recommend to use our prepared style sheet for J.UCS you can obtain by sending email to JUCS@iicm.tu-graz.ac.at, Subject: [latex]. This style file will be ready by 08-1994.

3.4 DVI Please use common fonts found on most computers. Please do not use decorative typefaces.

4 References [Maurer and Schmaranz 1994] Maurer, H., Schmaranz, K.: "J.UCS - The Next Generation in Electronic Journal Publishing"; J.UCS (Journal for Universal Computer Science) 0, 0 (1994), 2-20.

[ACM 1994] "The Full Computing Reviews Classification System"; Computing Reviews 35, 1 (1994), 6-16.

Acknowledgements We acknowledge the kind permission of ACM to use their classification system and the fact that ACM is actively encouraging J.UCS by operating a foundation server.

               Journal for Universal Computer Science

                             Cris Calude
                (University of Auckland, New Zealand)

                            Hermann Maurer
               (Graz University of Technology, Austria
                       hmaurer@iicm.tu-graz.ac.at)

                             Arto Salomaa
                    (University of Turku, Finland)



1 Introduction

Almost all researchers in computer science  have access to Internet by
now: with some   2 million Internet nodes  at  the time of  writing an
estimated 20-100 million people can connect to  Internet, many of them
directly from their desk.

Internet  has    become   an  increasingly    powerful    information,
communication and  cooperation system. It is clear  that the  time has
arrived to use Internet for the distribution  of a prestigious journal
in computer science  that is universal in three  ways: it  can be used
world-wide  and at any  time of  the day or  night,  and it covers all
aspects of computer science.

Observe that the  first two aspects  can be guaranteed  by a judicious
use of network facilities  as described later; the  third aspect - the
coverage of a wide spectrum  of areas -  would make a printed  journal
too  bulky  and  too  cumbersome  to  use.   Proper use  of  computers
eliminates this problem.

This project  describes the creation of such  a  journal, the problems
involved and  the solution adopted,  and how this journal, the Journal
for Universal Computer Science (J.UCS) will operate.
J.UCS will   appear  in 12  yearly issues,    starting in January  95.
Submissions will be accepted starting Sept. 1, 94.

The rest of this paper is structured as follows. After introducing the
basic premises  in [Section 2], a  review of problems and solutions is
presented  in [Section 3].  In  [Section 4] the process of submitting,
refereeing and publishing a paper  is described in detail. [Section 5]
mentions some further     general points and future  extensions,   and
[Section 6] contains a few references.


2 Basic Premises

J.UCS, the Journal for  Universal Computer Science will be distributed
mainly   in electronic form. However,  a  CD-ROM  version will be made
available at the end  of each year for  archival purposes. Indeed, the
CD-ROM version   will include a  print utility   that  will allow  the
printing  of individual papers, or  all  papers, or   all papers in  a
coherent subject area, so that organisations can - if they wish - make
printed versions of the  journal or parts of  the journal available to
their clientele.Also,an  official version will  be availble in printed
form around the same time the CD ROM is distributed.

J.UCS is supported by Springer Publishing Company: Springer has agreed
to mention J.UCS  in some of  its  publications and mailings; Springer
will be the distributor of the CD-ROM version  mentioned and will also
publish and   distribute  an  official  printed  version.  Thus, every
contribution   accepted will not only  appear  in electronic form, but
also as part of a refereed, printed high quality journal.

If sucessful as expected, Springer will  operate J.UCS on a commercial
bases from 1997  onward. The  yearly  subscription will be  around  US
$100.--  per  year.  One  such  subscription by  any organisation will
allow free access to the journal for all  members of that organisation
from their  workstations or  terminals,  albeit only   one  user at  a
time. Suitable licensing procedures  that are convenient for all users
have been worked out. They will be desribed at a later stage.

J.UCS is  a   high  quality  publication.  Each  submission  will   be
scrutinized by a  minimum of three  referees  and accepted only if  it
measures up   to the standards   of  prestigious printed  journals  in
computer science.  J.UCS is published  in volumes  (one per year) with
monthly issues.     The material is structured    into  pages that are
numbered  consecutively. Thus, papers  can  be quoted  exactly like in
usual  journals,  with name(s) of  author(s), title,  name of journal,
volume  number,  issue number, and  page  numbers. An  editorial board
consisting of over 100 eminent computer  scientists covering all areas
of computer science and coming from all corners of the world is in its
formative  stage and will ensure that  a paper appearing in J.UCS will
be as   prestigious  as  a  paper in    any  other reputable  refereed
journal.     The original editorial   board  constitutes  the board of
"Foundation Editors"  and will be  extended in the  following years as
seems necessary.

The  process   of   submitting  papers,  of   refereeing   papers, all
communications  between  authors and editors,   and the access  to the
papers   will     mostly   be    carried    out    electronically  via
Internet. However, papers can  always  be printed out  for refereeing,
for reading, for archiving  or even for distribution. The distribution
of individual  contributions in  the  J.UCS for  non-commercial use is
expressly  permitted    free   of charge  unless     explicitly stated
otherwise.  The distribution of whole issues  of  the J.UCS is handled
exclusively by designated central servers [see Section 3].

J.UCS is  operated on a non-profit basis:  editors and  referees carry
out their  work  on  an  honorary basis,  as  is the   case with  most
professional   journals.  Nevertheless, J.UCS  will  only be available
free of charge  during a trial  period of two  years, i.e. during 1995
and 1996. After  this initial period, charges to  recover the costs of
running the necessary  central  servers, potential network costs,  and
sundry  items, will be collected as  will be explained in [Section 3].
Thus, J.UCS is not intended to be a free publication. However, despite
its high quality  it will certainly  be less expensive than comparable
printed journals, and much easier to peruse.

We believe that journals such as J.UCS will eventually replace printed
journals. However,  the J.UCS  attempt is not  seen  as competing with
current publishing  companies but rather as  a large scale experiment:
if successful - and we firmly believe it will be - J.UCS might suggest
how professional publishing houses should go about the distribution of
journals and even books in the future. Note that most current computer
journals  do not pay  fees or royalties  to authors,  and neither will
J.UCS   .  However, in  the  system  used for  transporting  J.UCS the
charging  mechanism could  well be  employed in the  future to collect
royalties for contributions in other  electronic journals or for books
published in a way similar to J.UCS.

Contributions in J.UCS can be located and read (on the screen or after
being printed  out)   much  like   in  any other  journal.    However,
contributions can  also be located  by  searching for keywords  in the
title, in the list of keywords supplied by the author, in the text, by
author, by category,  and by combinations  thereof.  All contributions
are put  in one or  more categories based  on a  classification scheme
used by  ACM in their  Computing Reviews (CRCS). Hence, e.g. searching
for   all papers between  95 and  97  with classification E.1 or "Data
Structures" would  produce  a "subjournal"  of  all papers   of  J.UCS
published in  the three years 95  to 97 classified as contributions to
"Data Structures". Note that  contributions   may well be   classified
under more than one category.  Typically, a paper on "Hypertext" might
be  classified  as  H.5.1.3 ("Multimedia  Information Systems)  or/and
I.7.2  ("Document  Preparation"). The  classification  scheme of ACM's
Computing  Reviews is quite detailed and   fairly up-to-date (the last
revision ocured  less than two  years ago).  Please observe  that  the
complete classification is always printed in the January issue of each
year of the Computing Reviews: this also  contains an "inverted list",
i.e. looking  up  any title  does give   you  immediately the  correct
classification. The CRCS update editor  is  Professor Neal S.  Coulter
from the Florida  Atlantic University who we  has also joined J.UCS as
one   of   the Foundation  Editors.   Thus,   if changes or extensions
concerning  the categories are  necessary   J.UCS will have  immediate
information.

"Subjournals" of  J.UCS can  also be  created  on the basis  of  other
search criteria such as author, keywords, etc.

The main advantages of J.UCS over traditional journals are:
- fast turn-around time between submission of paper and publication;
- no limit on the  size of an issue:  all papers ready at a particular
  point in time appear in the next issue;
- easy access at  all Internet access  points  with a range of  search
  functions;
- less expensive than other journals;
- worldwide circulation;
- hyperlinks and annotation.

The  last point merits some explanation.  Authors of contributions can
refer to other papers using the usual reference mechanism. However, if
the  paper quoted has appeard  in J.UCS at  a prior stage, clicking at
the reference  leads  directly to  the  document at  issue,  and  to a
specific  location within the  document if such location ("destination
anchor")   has  been   specified. Conversely,   contributions  can  be
"annotated"  later  by the original   author or  other  persons.   All
annotations go through an editorial   process and are dealt with  like
"letters to  the editor"; the main  difference is that, when reading a
document with annotations, the presence of annotations is pointed out:
hence readers  may be alerted to new  results, corrections  of errors,
novel developments,  etc.  The process leading  to such annotations is
described in more detail in section 4.


3 What is the Big Deal?

Bulletin boards, collections  of  pictures and  software modules,  and
electronic journals have been existing in Internet for a long time. So
what is new about J.UCS, why is it such a great idea?

Well,  the  idea  is neither  great  nor new.   Literally thousands of
researchers  have  had it  before, and  some  have  already acted,  by
issuing  regular  journals, newsletters   or even   whole user-written
encyclopedias via Internet. However, all attempts to  date that we are
aware of are restricted  to a narrow area, and/or  are limited to  the
use of certain   software/hardware  platforms, and/or do not   support
sophisticated searching  techniques  for  locating papers and/or   are
lacking a  serious refereeing structure   (and  hence the prestige  of
printed journals) and are  somewhat  hampered by  the less than  100 %
reliability of long-range network  connections.  For one  example  see
[Steinberger 94].

J.UCS aims at  covering computer science   in general; its quality  is
assured by a large  editorial  board with eminent  computer scientists
and  a thorough refereeing process; it  is largely format and platform
independent and deals with the  problem of network (un)reliability  by
means of a distributed server  approach. Both points are elaborated in
what follows in more detail.

J.UCS   is  based on  a   networked  multimedia system called  Hyper-G
(see.e.g.   [Kappe, Maurer,  Scherbakov   93] and [Kappe, Maurer  93])
developed   by   a  team   of  specialists  between  1989  and  today.
Developments of further Hyper-G features and maintenance of the system
is guaranteed till  at least  2000 due to  contracts with  a number of
large organisations using Hyper-G,  including e.g. a growing number of
universities,  museums,  and the   European Space Agency.   Hyper-G is
based on  a   client/server architecture with   the server  running on
standard UNIX   machines (e.g.  from  SUN,DEC,HP,SGI)  and clients are
available for UNIX (both under X Windows and for simple terminals) and
Microsoft   Windows.   A client  for   an  Apple  Macintosh  is  under
development.  All  Hyper-G  software is  available free of  charge (by
anonymous    FTP;  look  on    host  iicm.tu-graz.ac.at   in directory
pub/Hyper-G). While the software is currently in beta stage, a version
1.0 is to be released on June 30, 94. It is not necessary to install a
server for casual use of J.UCS.

The server stores collections of  document clusters, where a  document
can be a text  file, a picture, an  audio- or videoclip, or some other
data-type.  For  J.UCS, only  text files  in English  and pictures are
permitted, initially.  (See   also  [Section 5]). Information can   be
accessed  using menus,  various   search-techniques and via  hypertext
links.

To use the  material, a viewer for  the type of  terminal at issue  is
necessary.  Viewers are supported  for Windows, Macintosh and X-Window
platforms (and  an  ASCII-text only  viewer  for VT100 displays).  All
viewers can be downloaded by anonymous FTP. Hyper-G is compatible with
WWW  [Berners-Lee 92] and  Gopher [Alberti 92] to  the extent that WWW
and Gopher viewers   can  be used   for Hyper-G   with some  loss   of
functionality.  Since  stable  Hyper-G-specific viewers  are available
right now for Windows and X-Windows (and more elegant versions by June
94),  and  a  Mac Viewer   is under development,  the use   of Hyper-G
specific viewers is recommended for J.UCS.

Textual information is stored in Hyper-G in HTF format (a format based
on SGML), and pictures  are  used where HTF    is not general   enough
(e.g. for  complex formulae). Both  inline  images and external images
are supported in HTF.

The  strength of Hyper-G is that  a number of widely-used text formats
can be converted  automatically to Hyper-G  internal form and can then
be viewed  on  a variety of platforms  such  as PC (Windows),   Mac or
Unix-workstations (X-Windows).

The  central J.UCS  server  will reside at   the  IICM (Institute  for
Information  Processing and Computer Supported  New Media) of the Graz
University of  Technology.  However, to be  less dependent of Internet
connections to Austria a number  of J.UCS  servers scattered all  over
the world will be set  up. Servers set up by  the end of 94 are called
the "Foundation Servers". Further servers are  welcome and expected to
join later. To set up a  J.UCS server is easy:  a Unix machine with at
least  a few  hundred  MByte  free   harddisk  space and  an  Internet
connection is  all that  is  necessary.   The J.UCS  server   software
(Hyper-G) is  available free of charge  by anonymous FTP.  Every J.UCS
server registers  as  such with the IICM  and  is thereby entitled  to
download regularly  the new issues  of J.UCS. Downloading will be free
throughout 96. A nominal yearly fee to  cover expenses will be charged
thereafter. J.UCS  servers are encouraged to   pass on their  costs to
users, in turn.

Users  can  read the  J.UCS by accessing   any  of the available J.UCS
servers.  Clearly, major universitites and research organisations will
be well advised to run their own J.UCS server: this way, access to the
J.UCS is optimally fast,    independent of network problems  and   the
server (based on  Hyper-G, a powerful  hypermedia system) may well  be
used    also   for  other purposes.      Alternativley,    a group  of
well-networked organisations may choose  to  run one joint  server for
reasons of economy, and still other institutions  may decide to access
the nearest public J.UCS via Internet.


4 The Submission Process

Papers are submitted as email to  (one of) the managing director(s) of
J.UCS;  initially this    job   will be   carried    out  by H.Maurer,
JUCS@iicm.tu-graz.ac.at.  They can be submitted in a number of formats
(typically  as  PostScript, LaTeX  or RTF files   as  produced by most
common word   processing  packages such    as Winword or  WordPerfect)
according to the "instructions for authors".

They are  automatically  converted to Hyper-G  format  and sent  to at
least two editors  who   (or   their designees) are  refereeing    the
contribution. Refereeing   can be done  using  a  Hyper-G viewer  that
allows to insert comments at any spot.

Note that the referee may decide  to have the contribution printed out
(in an initial  phase may even request  to have  printed versions sent
from   the managing editor),  make  notes  in  the print-out  and have
someone   else handle    the   (simple)  editing   with the    Hyper-G
viewer. Observe  further that  a  Hyper-G viewer is available  on most
major platforms,  hence referees (and readers!) of  the J.UCS need not
change their usual  "environment".  Refereed papers (or just  comments
and  an    evaluation form)  are  returned,  including recommendations
concerning  publishability, via Internet  to the  managing editor. The
managing  editor   notifies   the   author(s)  accordingly.    If  the
contribution is accepted, the  author carries out whatever changes are
necessary   and sends the  final version  to  the managing editor once
more.   The final version  is,     once more, converted  into  Hyper-G
format.  It is at this  point  only accessible to  the  author and the
referees  (if they have  asked to check  the final version). After the
author has potentially added some "hypertext links" (links to specific
places  in contributions  published    in J.UCS  earlier)  and   after
author(s) and referees have given their OK the paper is "finished" and
appears in the next issue.

The "instructions for authors" include information on permissible file
formats, on the  classification and keyword scheme,  on how to  insert
links, etc.

Having contributions in electronic form in  J.UCS certainly allows for
"links" in a hypertext sense to other points in the database. Links to
documents already existing in previous J.UCS issues  can be handled as
described  earlier.  "Forward" links  (i.e. links  from  a document to
another one  that    appeared later) can    only be  incorporated   as
"annotations" or by following links backwards. The latter situation is
easy to explain: suppose document y refers  to the (earlier) published
document x.  When  reading x the   user is  informed that  "there  are
documents referring to x" and all of those (clearly including the y in
the example) can be located with  a simple command. The situation with
"annotations"   is   similar, except    that  "annotations"  are   not
contributions  in a research sense  but just notes concerning previous
contributions. Such "notes"  ("letters  to the  editor") go through  a
refereeing process much like other contributions and are added only if
deemed appropriate. Thus, an annotation by an author pointing out that
the result in her/his earlier contribution x  has now been improved is
likely  to  be   incorporated,  an annotation  claiming  that  all  of
contribution x is nonsense is going to be scrutinized carefully before
being  added to J.UCS as  annotation. When annotations have been added
to a  document x their  existence is pointed out  to  the reader  of x
similar to the case of documents referring to x mentioned earlier.

Observe  that the philosphy of   links and annotations explained above
brings some of the benefits of hypertext to J.UCS, yet assures that no
contribution   that ever  enters J.UCS   can   be changed at  a  later
stage. We consider  this  essential  to have  the stability   in J.UCS
necessary to be able to quote contributions without fear that they may
change (as is happening in many other electronic information systems)!

It is finally worth mentioning that J.UCS  will have an ISB Number and
its contributions will be  reviewed and abstracted  like contributions
in other journals.


5 Future Points and Future Extensions

As J.UCS develops  it is clear  that additional demands will be placed
on it.    People will wish for   other file formats  to be  allowed as
input,   will wish for further search   options, still better viewers,
viewers for    still  more platforms,  the  possibility   for  private
annotations, for customization,  other language options and much, much
more ... including interfaces with other applications.

Many of these wishes  will be implemented,  we expect, on the basis of
the Hyper-G interface   specification and will  then  be added to  the
J.UCS. On  some,  like the interface with   an electronic  library  of
books, some groups are already actively working.

As  has been mentioned,  J.UCS will also be  distributed on CD-ROM for
permanent archival purposes,  and  J.UCS contributions can  be printed
out.  For an electronic  journal  this is  a severe limitation:  J.UCS
authors - if we forget the printing feature - could well be allowed to
also  incorporate animation,  movies,   sound, 3D scenes  with  direct
manipulation facilities, and much more.

The J.UCS will  follow   such  developments closely. We    expect that
eventually J.UCS  contributions may well  include material that cannot
be printed, and that "eventually"  will come around earlier than  most
of us would think.


6 References

[Kappe, Maurer, Scherbakov 93] Kappe, F.,  Maurer, H., Scherbakov, N.:
       Hyper-G - A Universal   Hypermedia  System; J.EMH  (Journal  of
       Educational  Multimedia and  Hypermedia)   2, 1 (1993),   39-66
[Kappe, Maurer 93] Kappe, F., Maurer, H.: "Hyper-G: A Large  Universal
       Hypermedia  System  and   Some  Spin-offs";   IIG Report   364,
       Graz/Austria (1993);  also   appeared  as  electronic  version,
       anonymous                FTP           siggraph.org,         in
       publications/May-93-online/Kappe.Maurer
[Berners-Lee 92]  Berners-Lee, T., Cailliau, R., Groff, J., Pollermann 
       B., "WorldWideWeb:  The   Information     Universe", Electronic
       Networking: Research,  Applications  and  Policy 1,  2  (1992),
       52-58.  
[Alberti92] Alberti B., Anklesaria F., Lindner P., McCahill M., Torrey
       D., "The   Internet  Gopher  Protocol:  A distributed  Document
       Search and Retrieval Protocol", Available by anonymous ftp from
       boombox.micro.umn.edu in directory pub/gopher/gopher_protocol.
[Steinberger  94]   Steinberger,  M.: "The    New  York Journal     of
       Mathematics", Available  on gopher nyjm.albany.edu or anonymous
       FTP on ftp_nyjm.albany.edu in directory /pub/nyjm


Acknowledgments

The idea for this project as  described originated in discussions with
my friends Cris Calude  and Arto Salomaa  over the last years. I  have
also mentioned  J.UCS to   many other colleagues  and  have  to  state
explicitly that the idea as such is not novel  at all, yet many of the
details (various formats, platforms, and editors) are reasonably scary
once    you look at them more     closely. However, having developed a
multimedia  system  capable   of handling  something  like   J.UCS  in
principle a number of the persons you find on the editorial board have
encouraged me to  go ahead and get  started. I want   to thank all  of
them, and    all  who have  joined  the   "Foundation   Board" and the
"Foundation  Network" for their encouragement  and trust. As sure as I
am that J.UCS will work based on Hyper-G I am  equally sure that there
will  be glitches,  and, according to   Murphy, at the  worst possible
moments. Please bear with me when they arise and be tolerant with some
(hopefully  small) problems: this is a  new and exciting frontier! The
editorial  board is explicitly  responsible only for  the ideas behind
J.UCS.    All problems with   management and   software  are my   sole
responsibility and nobody else's.

ACM  has endorsed our use of  the ACM Review Category System beginning
of June 94 and is going  to run their own  foundation server for J.UCS
as ACM.


----------------------------------------------------------------------
           Advancing The Ideas of World-Wide-Web : Hyper-G
                            Hermann Maurer
              (Institute for Information Processing and
                    Computer Supported New Media,
             Graz University of Technology, Graz/Austria
                  email: hmaurer@iicm.tu-graz.ac.at)


Extended Abstract

WWW (World Wide  Web)[Berners-Lee  92] has become the  most successful
networked multimedia system  employing the hypertext paradigm over the
last  few years: Documents consisting of  textual information can have
embedded pictures, movies or audioclips and reside on a  s e r v e r ,
accessible e.g.  via internet using suitable  v i e w e r s.  The only
structuring mechanism for  sets of documents  is the facility to place
-- in  hypertext fashion --  anchors in documents  leading to (linking
them  to) other   documents. Although this  mechanism can   be used to
create menu-like  hierarchical structures WWW  databases are basically
"flat" (stratified) collections of documents  linked together. Thus, a
WWW database can be seen as a graph whose  nodes are the links between
them.  WWW has  become an   easy to use   tool,  mainly for small  and
medium-scale multimedia  presentations that  are accessible world-wide
due to  the excellent  M o s a i c  - viewer that  is available on all
major platforms: X-Windows, Mac and MS-Windows.

However,   WWW has a number  of  limitations that become apparent once
tasks more complex than "a few hundred multimedia screen applications"
are considered.  No full-text search is  provided  as part of  the WWW
server, let  alone the possibility to search  across boundaries of WWW
servers; authorisation features are lacking, hence the installation of
a number of  independent  WWW servers within  an  organisation  is not
uncommon,  for the simple reason  of preventing access of unauthorised
groups. This fragmentation prevents more global searches: thus, one of
the main aims - to  tie information together  - gets  lost due to  the
lack of authorisation features and the boundaries  imposed by each WWW
server.

To overcome such weaknesses WWW offers an ingenious way out: it allows
to start arbitrary application programs, thus  letting users link into
other databases, employ  complex search   algorithms or activate   any
other program desirable on top of  WWW servers. This great flexibility
is achieved, however,  at a big  cost: the uniformity of the interface
disappears, different WWW  servers  start to behave  differently:  the
whole "jungle" of scattered databases each with a different feel as we
all know it from Internet starts to reappear, now on the level of WWW.

Realizing this dilemma, a group  of some 30 researchers and developers
at the  Graz  University of  Technology has started  to systematically
examine  the ideas,  structure   and  underlying  features  of   large
distributed multimedia  servers,   leading, eventually, to  a  concept
embracing WWW yet  more general  than WWW:  Hyper-G. Hyper-G has  been
developed carefully  to   ensure cross-operability with WWW.   Hyper-G
databases  have   gateways to  WWW  (and    Gopher [Alberti 92]),  and
conversely; the Hyper-G viewer A m a d e u  s (for MS-Windows) and H a
r m o n y (for X-Windows) will allow the perusal of WWW databases; and
the Mosaic Viewers of WWW can be  used to access Hyper-G servers. (For
more details  on  Hyper-G see [Andrews  94a], [Andrews  94b], [Hyper-G
94], [Kappe 93a], and [Kappe 93b]).

The  main difference between WWW  and Hyper-G  servers is that Hyper-G
provides much functionality integrated  into it (and hence uniform  in
nature)  that   has to   be implemented  on  top  of   WWW (and  hence
potentially differs  from site to site) and  that Hyper-G servers work
on a  truly  distributed platform:  a user can  activate  a  number of
Hyper-G servers (that   may or may  not be  arbitrarily geographically
dispersed)  in such a  fashion  that the  union  of all the  databases
involved appears  as  if  it were  one  single  database.  Indeed, the
Hyper-G concept is a bit deeper and more general:

The basic item of a Hyper-G database is a document cluster rather than
a single document:  this is a  convenient tool to  handle such diverse
features    as  multiple  languages,     multiple windows or  multiple
representations. A  typical example of the latter  is the treatment of
LaTeX documents in WWW (Mosaic) and Hyper-G: in Hyper-G the basic idea
is to store LaTeX documents as a cluster of two documents: one of them
is a textual document with in-line pictures for  all formulae (this is
the approach taken in WWW/Mosaic), the other document  is the DVI File
corresponding to the LaTeX document containing links to e.g. pictures,
i.e. a  file retaining  all the  precision and beauty  of the original
LaTeX version. For  casual browsing on  a medium resolution screen the
first alternative  is the  only viable one,  for  serious viewing  (or
printing on  a  laser  printer)  the  second  one  (not  available  in
WWW/Mosaic without some contortions) is the only one that makes sense.

Document   clusters   in   Hyper-G  are  put   together  in  so-called 
c o l l e c t i o n s, and  a  collection  can  be  part  of  one  (or
more) parent collections. Thus, Hyper-G  structures its documents into
a kind of hierarchy (actually not a tree, but  a DAG).  This is useful
for   many reasons: documents can  be  inserted without defining links
(not possible in   WWW:  a  document without  a   link to  it is   not
(properly) accessible in WWW;  it  is accessible in  Hyper-G, however,
due to the collection  structure); collections (and document clusters)
can  have attributes, allowing   Boolean searches on those attributes;
and although Hyper-G provides  the full anchor-link hypertext paradigm
it  also allows (Boolean or  WAIS-like)  full text searches within the
scope of any number  of user-selected collections.  Since each Hyper-G
database  is a  collection,  users  can activate  even  geographically
remote  Hyper-G databases   (better  still:  arbitrary sub-collections
within them) and perform powerful searches across all of them.

Note that such a facility is rather hard to implement in WWW: although
full   text search  can   be added  on  top  of  WWW databases,  scope
definitions are very  difficult and automatic searches  across various
WWW databases are next to impossible.  Thus, Hyper-G avoids the danger
of independent "WWW-empires",  the "Balkanisation" of databases as Ted
Nelson has so aptly called it!

However,  it must be clearly recognized  that Hyper-G generalises, but
makes full use of WWW and Mosaic facilities.

It is  worthwhile to look at  a specific example. Suppose a university
has five different WWW servers operated by five different departments,
each  department  authorized  to  modify only  its   own database, and
departments  unable or unwilling to combine  the data  for exactly the
mentioned authorization problems. Although a good  solution, it is not
perfect:  to find information  on  person xxx within that  university,
each of the five  databases has to be queried.  Maybe not even  all of
them support full  text  searching or may  support  it using different
mechanisms: thus, the problem "where do I have to look and how do I do
it" (well-known    from  the  world  of   Internet  and  international
databases) can arise  using WWW even  within a single institution (and
even   more  so   if   the    databases  are  spread   over    various
institutions). Using Hyper-G, each of the five mentioned WWW databases
can be converted into five  Hyper-G collections, all of them belonging
to the   collection "University yyy".    Authorisation to modify  data
remains where  it is  desirable,  yet a   single full-text search  for
"Person xxx"    in the collection  "University   yyy" will  reveal all
information    on  person   xxx,   if    any  such   information    is
available. Observe that no manual changes in any  of the WWW databases
are necessary;  nor is it necessary  to abandon the viewer  Mosaic, if
users have started  to like this beautiful  piece of software. On  the
other hand,  the  Harmony  viewer  (see  below)  does provide   all of
Mosaic's features and a few additional ones  (and is available free of
charge like Mosaic), so  may become a  welcome addition at some  stage
...

To take a larger and maybe more pertinent example: suppose a number of
universities  in  Germany   use   Hyper-G,  each  with    a collection
"Mathematics".  By defining  a  collection "Mathematics  in Germany" a
single    search   will  examine  all  sub-collections   "Mathematics"
automatically, independent of where they are located geographically.

We believe that above notion of unions  of collections defining scopes
for searches  (or other actions!)  is essential to  prevent that a new
kind of fragmentation occurring on a new level.

Hyper-G was developed using also knowledge of and experience with WWW;
Hyper-G is thus influenced by WWW and has systematically tried to stay
consistent with  WWW without giving  up   the insights gained  in  the
meantime:

- Big hypermedia systems must have a structure: a "flat" graph with no
  "semantic" meaning of links will not do for large systems.
- Activities  in  large networked   multi-media  systems   have to  be
  restricted to scopes definable by the users.
- Activities that are considered central (like searching, structuring,
  non-private annotations, etc). have to be integrated into  the basic 
  system so as to  avoid unsystematic proliferation  of "unorthogonal"
  features.

Hyper-G is  based on  above premises.More on  those  and other  points
(like  mechnaisms  for   gathering   statistics,billing  and  "active"
mail)will be contained in a full version of this paper. However, a few
more specific aspects should be mentioned:

The annotation concept  in  WWW (actually part  of  the Mosaic client)
allows "private" annotations  that are stored locally. Hyper-G  allows
to define authorisation classes for annotations, permitting "private",
"group" or "public" annotations.

Links in WWW are restricted to textual anchors, while Hyper-G supports
anchors  in arbitrary data-types  like   pictures or movies. Links  in
Hyper-G   are  bi-directional.  Hyper-G    introduces a  sophisticated
authorisation mechanism defining  for  each user the  rights  to read,
create   links,  modify and annotate.   This   provides  the basis for
sophisticated customisation and even CSCW within  Hyper-G that have to
be -- like all  other more sophisticated  features -- built on  top of
WWW (potentially creating confusion and incompatibility).

Hyper-G  is  being    used as information    system  at  a number   of
universities  (Graz University   of Technology and   the University of
Auckland are two examples); it has been selected as information system
by major organisations such as ESA  (European Space Agency), it is the
basis of a multi-media guidance system  by large museums or exhibition
operators (such  as the new Museum  of New Zealand,  or the  Images of
Austria Presentation at the  EXPO' 92 at Sevilla);  it is the platform
of one of  the  most  ambitious (30  GByte data)  multimedia  projects
anywhere (the millenium celebration  of Austria) and  is the  basis of
the first serious attempt  of electronically publishing a high-quality
journal in   computer  scince, J.UCS (Journal  of   Universal Computer
Science): J.UCS  is suported  by  Springer Pub.Co.,  has an  editorial
board  of   some   150 prominent computer     scientists  and some  50
universites world-wide have agreed to act as server.

Hyper-G, as a  late-comer in the field, has  been able  to profit from
and  incorporate experience from earlier projects   such as Gopher and
WWW. And despite the fact that Hyper-G will not be officially released
before June 30, 94 above list does  show a fairly wide acceptance even
of its pre-beta-release version.

Since Mosaic has been the main driving force  for WWW it is worthwhile
to mention that    the current X-Windows  viewer  of  Hyper-G  will be
replaced by  Harmony.  (The current Harmony   version  is available as
development   prototype    for functionality tests    if  specifically
requested for  such tests; it  must not  be considered an  operational
tool before June 30, 94 [Hyper-G 94]).

Harmony  includes  all features  of  Mosaic, plus  a graphical browser
giving document-type,  history, in-and-out links,  dynamic and  static
environments, and incorporates  a  viewer  of  3D objects  and  scenes
(including navigation within them) plus  a first attempt at  producing
3D "information landscapes".

The  MS-Windows Viewer  A m a d e u s  is  available as of July 94. It
implements a subset of Harmony's features on a MS-Windows platform.

Summarizing,  WWW  has   been successful   in   establishing networked
multimedia as a major option for information systems of the future.

Hyper-G has   been   built  using experiences   with   WWW   and other
large-scale    networked    multimedia   systems,    preserving   full
interoperability with  WWW, yet incorporating  all those features into
the basic   system     that   have been   universally      accepted as
indispensable.  In this sense, Hyper-G  tries to contribute  to a more
uniform and controlled environment of the world opened by WWW.


References

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[Kappe 93a] Kappe, F.,   Maurer,  H., Scherbakov,  N.: "Hyper-G  --  A
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