the "repository ecology" approach to describing cross-search service management phil...
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The "repository ecology" approach to describing cross-search service
management
Phil Barker and Malcolm Moffat,ICBL, Heriot-Watt University
Last modified: Sept 2007.
See also: http://www.icbl.hw.ac.uk/publicationFiles/2007/CrossSearchEcology/index.html
This work is licenced under the Creative Commons Attribution 2.5 UK: Scotland License. To view a copy of this licence, visit http://creativecommons.org/licenses/by/2.5/scotland/ or send a letter to Creative Commons, 171 Second Street, Suite 300, San Francisco, California 94105, USA.
Introduction : Aims
• Describe interactions in setting up and managing a cross-search service
• Show how the ecology view of these interactions enhances the architecture view:– Entities not in the architectural view– Keystone species– Habitat and niche in ecology– Competition
Introduction : PerX
• Pilot Engineering Repository Cross Search– develop a pilot service which provides subject specific
resource discovery across a series of repositories of interest to the engineering learning and research communities
• Funded by the Joint Information Systems Committee (JISC) of the UK University funding bodies
• Working within the JISC’s “Information Environment”
The PerX Use Case
An Engineer is engaged in some work...
attentionTask
Engineer
The PerX Use Case
An Engineer is engaged in some work, when suddenly they require further information to complete their task
attentionTask
Engineer
?
attentionTask
Engineer
The PerX Use Case
So the Engineer goes to their computer and performs a search on the PERX website.
!
See http://www.icbl.hw.ac.uk/perx/
info
rmat
ion
attentionTask
Engineer
The PerX Use Case
The PERX systems cross searches a series of repositories of interest and as a result the engineer finds the information needed to complete the task effectively.
The world is made a better place.
The Architectural View
JISC Information Environment
Technical Architecture by Andy Powell
See http://www.ukoln.ac.uk/distributed-systems/jisc-ie/arch/
IE Architecture view of PerX
Perx aggregator
Data Data Data
Data
User interface
DataService Registry
The website used by the Engineer is a presentation layer connection to PerX. The PerX service is an aggregator in the fusion layer of the IE architecture, it cross searches information about resources which is held by several services in the provision layer. PerX knows the nature of these content provider services and how to search them because of data provided by a service registry which is part of the shared infrastructure. Other shared services (not shown) may be involved in delivering the resource.
The Ecology View
PerX Landscape analysis
See http://www.icbl.hw.ac.uk/perx/sharedservices_IESR.htm
Perx aggregator
Data
User interface
Data
Admin interface
PerxService Manager
Service Registry
The PerX service manager needs to identify suitable content providers and set up connections to them using the Perx Admin INterface (PAIN).The Service Registry does not (yet) contain reliable information to help him. No machine to machine connection is implemented.
Perx aggregator
Data
Information resources
EngineeringCommunity
User interface
Data
Admin interface
InformationCommunity
info
rmat
ion
information
information
informationEngineer
Content providerService Manager
PerxService Manager
However, the PerX service manager is part of a community active in providing information resources for engineers (for example the service managers of content providers & other end user services).
This community is in contact with the Engineering community in order to ascertain the needs of Engineers and so can provide information on providers of data about information resources relevant to engineers.
PerX Landscape analysis
See http://www.icbl.hw.ac.uk/perx/sharedservices_IESR.htm
Perx aggregator
Data Data Data
Data
Information resources
User interface
Data
Web site
Data
Admin interface
InformationCommunityin
form
atio
n
information
information
Content providerService Manager
info
rmat
ion
PerxService Manager
PerX Setup & Maintenance
In order to set up and maintain a cross search of a content provider the PerX service manager uses information from the content provider’s website, other resources provided by the information community, and frequently, a great deal of direct contact with the content provider service manager.
See http://www.icbl.hw.ac.uk/perx/setupmaintenance.htmand http://www.icbl.hw.ac.uk/perx/casestudyoxford.htm
PerX Setup & Maintenance
Perx aggregator
Data Data Data
Data
Information resources
User interface
Data
Data
Admin interface
InformationCommunity
info
rmat
ion
information
information
Content providerService Manager
info
rmat
ion
PerxService Manager
Content provider’sCommunity
Web site
Sometimes it was not possible to establish contact with any individual as the service manager at the content provider. In such cases we are left trying to work with a nebulous community around the service provider. Only when someone within that community had taken the time to expose information about interoperability services (e.g. on a website) was it possible to establish a data feed.
The Cross-search “habitat”
Content provider’sCommunity
Perx aggregator
Data Data Data
Data
Information resources
EngineeringCommunity
User interface
Data
Web site
Data
Admin interface
Data
InformationCommunity
info
rmat
ion
info
rmat
ion
information
information
information
attentionTask
Engineer
Content providerService Manager
info
rmat
ionService
Registry
info
rmat
ion
PerxService Manager
Entities Interacting with PerX
• The ecology view adds the following entities to those in the architecture:– PerX service manager– Information community– Content provider service manager– Content provider community
• (Others exist, e.g. funder and host institution)
Look at interactions between just two of these in more detail...
• is there any way to limit the cross-search to just the information relevant to Engineers?
Information required from the content provider...
Web site
Content providerService Manager
info
rmat
ion
info
rmat
ion
PerxService Manager
• What classification scheme (if any) has been used to describe the subject of resources in the content providers collection? – (please can we have something richer
than the default simple DC metadata?)
Information required from the service provider...
Web site
Content providerService Manager
info
rmat
ion
info
rmat
ion
PerxService Manager
• What criteria are used to provide sets (if available) for an OAI-PMH data provider?
Information required from the service provider...
Web site
Content providerService Manager
info
rmat
ion
info
rmat
ion
PerxService Manager
• Why are some of the sets empty?
Information required from the service provider...
Web site
Content providerService Manager
info
rmat
ion
info
rmat
ion
PerxService Manager
• Why is the XML returned invalid?
Information required from the service provider...
Web site
Content providerService Manager
info
rmat
ion
info
rmat
ion
PerxService Manager
• Why has the service stopped responding?
Information required from the service provider...
Web site
Content providerService Manager
info
rmat
ion
info
rmat
ion
PerxService Manager
• Why is the number and range of resources available for discovery through the interoperability protocol different to what was available through the native interface?
Information required from the service provider...
Web site
Content providerService Manager
info
rmat
ion
info
rmat
ion
PerxService Manager
• Why does the metadata available to PerX not include any locator or identifier by which the resource could be obtained?
Information required from the service provider...
Web site
Content providerService Manager
info
rmat
ion
info
rmat
ion
PerxService Manager
• Time and context dependent• Rich information, • Not readily obtained by protocol
“identify” or “explain” requests.• Characteristic of immature
implementations.• Require action, maybe by both
parties, in order for requirements of both parties to be met: coevolution.
Information required from the service provider...
Web site
Content providerService Manager
info
rmat
ion
info
rmat
ion
PerxService Manager
Locality and Habitation
"The habitation of a technology is its location within a network of relationships...
"We cannot overemphasize a key point here: only the participants of an information ecology can establish the identity and place of the technologies that are found there."
Nardi and O'Day “Information ecologies” (1999) p 55
Habitat and Niche
"[The term ecological niche] is often used loosely to describe the sort of place in which an organism lives as in the sentence: 'Woodlands are the niche of woodpeckers'. Strictly, however, where an organism lives is its habitat. A niche is not a place but an idea: a summary of the organism's tolerances and requirements"
Begon et al “Ecology from Individuals to Ecosystems” (2006) p 31
Tolerances and Requirements, 1.
• Require attention and commitment from content provider service manager.– Either to answer questions or implement changes– Can be person to person or mediated through.
channels like website, “explain” function (ZeeRex).– Currently a lot of the information required is rich and
context specific.– Content provider and cross-search provider might
both need to change (co-evolution).
• Identify the service manager as a “keystone species”.
Tolerances and Requirements, 2.
• Users. There's no direct need for users(!) however with users come:– Funding– Attention and commitment from content providers– Good contacts within the Information Community
But users won't be interested in information obtained only by one interoperability protocol or from one type of repository...
Tolerances and Requirements, 3.
• A cross-search service should be able to cope with a diversity of interoperability protocols (OAI-PMH, SRW/U, proprietary), metadata schemas and cataloguing practices – however, this diversity adds a technical overhead.
Panda, by Tancread on http://www.flickr.com/photos/tancread/
http://creativecommons.org/licenses/by-nc/2.0/
Competition
• Where two species (partially) occupy the same same niche in the same habitat they will be in competition
• Also competition from other individuals of the same species.
• Competition for– Users– Attention– Funding
Reflections
• An architecture is a static ideal design; an end point. It is limited to technological entities.
• The ecological approach adopted here describes– what actually exists / happens– an evolving system– it includes people explicitly ... the people turn out to be
important.
Reflections
• The people I spoke to about this work were far more able to engage with this approach than when I speak to them about architectures.– they talk about what they do, who they interact with,
not the big picture. Locality, habitat, and niche. – process akin to enthological evaluations or action
research?– a description of the niche requirements should feed into
the development of shared services
Thankyou.
• questions....