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Astronomical Data Analysis Software and Systems XIII ASP Conference Series, Vol. 314, 2004 F. Ochsenbein, M. Al len, and D. Egret, eds.

TWiki: A Collab oration Platform for VO Pro jects
M. C. Leoni, M. Dolensky European Southern Observatory, Karl-Schwarzschild Str. 2, Garching bei Munchen, D-85748, Germany Ё R. Bentley Mul lard Space Science Laboratory, University Col lege London, Holmbury St. Mary, Dorking, Surrey RH5 6NT, UK T. Goodwin, T. Linde University of Leicester, Dept of Physics & Astronomy, University Road, Leicester LE1 7RH, UK Abstract. Finding an easy way of sharing knowledge and experience in a geographically dispersed pro ject team is not easy. The TWiki is a Web-based collaboration platform. It looks like a normal Internet web site, but everybody can change pages or add content by just using a browser. A revision control keeps track of changes. Several Virtual Observatory pro jects use this type of web site to share info among pro ject members and across pro jects. This is an experience report on the usage and maintenance of TWiki sites in Astronomy. Even if at first it seems almost the opposite of how the Web and on-line communications "normally" work, it is intuitive and aspires to the Zen ideals known as Wabi-Sabi: "It finds beauty in the imperfect and ephemeral and constantly evolving".

1.

Introduction

Working in a distributed team always means spending a lot of time trying to keep everybody up-to-date about what other members are doing, as well to keep people in touch with each other. The infrastructure aims at facilitating pro ject communication, therefore helping to share knowledge, the status and vision of the pro ject, to draft ideas, and to synchronize different teams. The TWiki is a web-based collaboration tool that offers the possibility to use a web site like an enhanced white-board. TWiki was not invented by the Astronomy Community but it perfectly suites our needs. The astronomy-related TWiki sites considered in this paper have all seen a constant increment both in the number of visitors and users, as well as in the amount of pages created/updated and files uploaded. These TWiki sites are ALMA, Astrogrid, Aus-VO, AVO, EGSO, IVOA (Table. 1). 307 c Copyright 2004 Astronomical Society of the Pacific. All rights reserved.


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M. C. Leoni et al. Table 1. Astronomical TWiki sites

Pro jects ALMA Astrogird Aus AVO EGSO IVOA

Portal

http://almasw.hq.eso.org/almasw/bin/view/Main http://wiki.astrogrid.org http://www.aus-vo.org/twiki/bin/view/Main http://www.euro-vo.org/intranet http://www.mssl.ucl.ac.uk/grid/cgi-bin/twiki/view.cgi/Main http://www.ivoa.net/intranet

2.

WikiWords (i.e. Terminology)

A TWiki Web is a collection of pages grouped by some logical meaning. A Topic means a wiki page with all its content. 3. Usage/Usability

Usage statistics are plotted in Fig. 1 and Fig. 2: The former describes the number of pages modified and the number of files uploaded, i.e. real interactions with the Twiki. The latter displays the number of pages visited in each month. To create these charts, only relevant Webs of each TWiki site were taken into account. The simplicity of TWiki is mostly due to the fact that one can access and work on such a site simply by using a web-browser. It is not necessary to install any particular client software. To have an idea of how many users are really working with the TWiki, Table. 2 presents the number of collaborators who put material on the mentioned sites. Table 2. 2003 TWiki-VOs Users
Jan TWiki ALMA Astrogrid 54 Aus-Vo 7 AVO 121 EGSO 35 IVOA 11 Feb Mar Apr May Jun Jul Aug Sep Oct

55 15 123 35 19

59 16 123 35 37

64 17 123 35 52

84 17 123 35 67

87 17 123 35 71

94 18 123 35 74

22 94 19 123 37 78

41 95 19 126 37 83

57 101 20 139 45 93

4.

Installation and Maintenance

The are only a few system requirements when setting up a TWiki server. Even though it was originally designed for Unix-like Operating Systems (and it is actually developed in a Linux/Apache environment) it works also on Microsoft


TWiki: A Collaboration Platform for VO Pro jects Windows.

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Implemented as CGI scripts in Perl, it works on port 80 without any special firewall requirements. To assure transparency a revision control system (RCS) keeps track of changes and all prior revisions are directly accessible. The e-mail notification service1 makes use of the Net::SMTP Perl module (alternatively sendmail).

5. 5.1.

Pros and Cons Pros

- Easy to use, easy to maintain. - Full public access on the Web. - Simplified built-in markup language. - Instant updates of the on-line material. - Constant development to assure new features every month (with simple plug-in format to facilitate the installation phase). - New plug-ins, provided by an archive user community, constantly enrich the functionality. 5.2. Cons

- The hardest piece is to get people to use it: ...Once they get started they can't live without it anymore. - It is difficult to maintain a clear document structure since everybody can add pages and documents. So, the more active the user community, the bigger the mess that may result. - Being a purely web based tool, the editor is a rather basic HTML form; there is a more advanced Javascript editor though.

1

Inform users about changes in the TWiki Webs.

Figure 1.

Uploaded documents and modified pages.


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Figure 2. References

Visited Topics on all six TWikis.

TWiki.org, http://twiki.org Wabi Sabi, http://www.art.unt.edu/ntieva/artcurr/asian/wabisabi.html