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  <front>
    <journal-meta />
    <article-meta>
      <title-group>
        <article-title>Computer-Supported Collaborative Knowledge Modeling in Ecology</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Ioannis N. Athanasiadis</string-name>
          <email>ioannis@idsia.ch</email>
          <xref ref-type="aff" rid="aff0">0</xref>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>Deana D. Pennington University of New Mexico MSC</institution>
          <addr-line>03 2020 Albuquerque, NM 87131</addr-line>
          ,
          <country country="US">USA</country>
        </aff>
        <aff id="aff1">
          <label>1</label>
          <institution>Istituto Dalle Molle di Studi sull'Intellienza Artificiale Manno</institution>
          ,
          <addr-line>Lugano</addr-line>
          ,
          <country country="CH">Switzerland</country>
        </aff>
      </contrib-group>
      <abstract>
        <p>We describe collaborative efforts between a knowledge representation team, a community of scientists, and scientific information managers in developing knowledge models for ecological and environmental sciences. Formal, structured approaches to knowledge representation used by the team (e.g., ontologies) can be informed by unstructured approaches to knowledge representation and semantic tagging already in use by the community. Observations about the process of collaboration between the team and the community are used to generate an interaction model for supporting software tools.</p>
      </abstract>
      <kwd-group>
        <kwd>eol&gt;Collaboration</kwd>
        <kwd>observation</kwd>
        <kwd>ontologies</kwd>
        <kwd>concept maps</kwd>
        <kwd>ecological knowledge</kwd>
      </kwd-group>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>1. INTRODUCTION</title>
      <p>
        Understanding and solving global environmental problems
requires a new kind of science: science that is interdisciplinary,
collaborative, and responsive to the needs of decision-makers [
        <xref ref-type="bibr" rid="ref17 ref29 ref9">9,
17, 29</xref>
        ]. Cross-disciplinary networks of scientists worldwide are
marshalling their understanding in efforts to provide scientific
results that target complex problems. Formal networks of
scientists—such as the Long Term Ecological Research (LTER)
networks originally developed in the US (http://www.lternet.edu/)
and now located worldwide (http://www.ilternet.edu/)—employ
information managers whose primary task is to provide online
access to relevant information. With available resources rapidly
increasing, the difficulty of discovering and making use of those
resources (e.g., knowledge synthesis) is increasing as well,
especially in conjunction with rapid expansion of the Web as a
whole. A number of efforts are underway to enable better sharing
of data, information, and knowledge within the natural sciences,
as discussed in [
        <xref ref-type="bibr" rid="ref1 ref16 ref22 ref26">1, 16, 22, 26</xref>
        ]. These efforts include
ontologydriven applications that make use of formal semantic reasoning to
enable integration of heterogeneous resources.
      </p>
      <p>Ontology-based approaches require eliciting shared knowledge
from large communities of domain scientists and decision makers.
Ferdinando Villa
University of Vermont</p>
      <p>617 Main St
Burlington, VT 05405</p>
      <p>+1-802-656-2968
•
•
•</p>
      <sec id="sec-1-1">
        <title>Disparity in work and benefit. Scientists who have the</title>
        <p>
          knowledge that must be incorporated into ontologies lack
understanding of the benefits that semantic modelling will
ultimately provide them and are unwilling to engage in
activities that do not provide clear, short-term benefits.
Information managers who might be able to provide some of
the knowledge and may even understand the long-term
benefits for the scientists have more immediate problems and
focus their time on developing short-term solutions. Hence,
ontology development requires “additional work from
individuals who do not perceive a direct benefit” [
          <xref ref-type="bibr" rid="ref10">10</xref>
          ].
Critical mass and Prisoner’s dilemma. Ontology-driven
applications are expected to be most useful when multiple
users share their resources. The work involved in ontology
development and annotation of resources is not justified by a
single user. Hence, these projects require a “critical mass of
users to be useful” [
          <xref ref-type="bibr" rid="ref10">10</xref>
          ] and early adopters must commit to
substantial effort with no guarantee that others will follow.
Grudin makes a number of relevant suggestions for addressing
these problems [
          <xref ref-type="bibr" rid="ref10">10</xref>
          ]:
        </p>
      </sec>
      <sec id="sec-1-2">
        <title>Reducing the work required of non-beneficiaries and indirect beneficiaries.</title>
      </sec>
      <sec id="sec-1-3">
        <title>Design processes that create benefits for all group members.</title>
      </sec>
      <sec id="sec-1-4">
        <title>Build in incentives for use.</title>
        <p>
          Developing an innovative approach to community-based ontology
development that incorporates these suggestions presents an
illdefined, unstructured problem requiring creative thinking.
Development of solutions to such problems can be conceived as
two-phased [
          <xref ref-type="bibr" rid="ref27">27</xref>
          ]: 1) an idea generation phase that requires a
combination of divergent thinking and domain expertise, and 2)
an implementation phase. In this paper, we focus on the idea
generation phase, envisioning systems that could effectively link
short-term user needs supported by informal semantics with
longer-term formal ontology development. The ideas are based
on our experiences working with these science communities,
understanding of their tasks, and ongoing efforts at
communitybased ontology development. The goal of this paper is to propose
innovative designs for systems that enable collaborative ontology
development derived from our particular case, and also to
stimulate vibrant debate and creative thinking about generic
issues that confront interdisciplinary ontology development
efforts.
        </p>
        <p>We begin with a brief description of the participants. That is
followed by a brief description of our ontology needs and an
upper-level ontology that we have created. These sections
provide context for understanding the kinds of knowledge that we
need to elicit from the community and the resources that we have
available to apply to the problem. Next, we present a set of use
cases for supporting semantic-based work tasks that are
commonly undertaken in our communities. We describe how
these tasks provide an opportunity to capture knowledge relevant
to formal ontology development while providing immediate
benefits to the users. We provide a high-level conceptualization
of a system that we are currently designing to implement these
ideas. Then, we describe methods that we have already
undertaken to extract knowledge from users in direct and indirect
ways, without the support of enabling systems. These provide
real examples of tasks that inform ontology development. We
discuss how these could be incorporated into our hypothetical
system in ways that limit the work required from the user. Lastly,
we abstract our specific problems and proposed solutions into a
simple model for enabling collaborative ontology development.</p>
      </sec>
    </sec>
    <sec id="sec-2">
      <title>2. PARTICIPANTS</title>
      <p>Initially, each project had its own Knowledge Representation
(KR) research and personnel. Several years ago we began to
collaborate with a view towards constructing ontologies that
would interoperate between projects, providing an opportunity to
leverage each others’ work but also creating a larger,
multidisciplinary group that was more capable of critical evaluation of
different proposed ontologies.</p>
      <p>The KR team has cross-disciplinary expertise in computer science
and domain science. It consists of two computer scientists with
expertise in ontologies, reasoning, and semantic mediation, and
four domain scientists with differing disciplinary expertise,
relatively high levels of computing experience, and varying
backgrounds in knowledge representation. The team has met
regularly to devise strategies for ontology development.
Discussion at these meetings ranges from formal symbolic logic
to philosophy of science to targeted discussion about implicit
knowledge embedded in datasets. Time and effort was required
to bridge disciplinary boundaries and understand inherent
assumptions that impact the teams’ ability to collaborate on what
is clearly an interdisciplinary task. Numerous real examples of
environmental data and analyses obtained from scientists and
information managers have guided and informed these
discussions. One of the domain scientists is tasked with
knowledge engineering, and is responsible for developing and
maintaining the ontologies in Protégé
(http://protege.stanford.edu/). Another is tasked with acting as
liaison to the scientific community.</p>
      <p>The KR team collaborates with the scientific and information
management communities to elicit domain-specific knowledge.
Few of the community collaborators have the time or interest to
cultivate an understanding of formal ontologies. Nor do they
fully understand the benefits of ontology-driven systems, since
few examples of these systems exist. Hence, their personal
commitment to ontology development is limited. Yet they
recognize that semantic approaches may provide future benefits to
them and are willing to help to the extent that it does not impede
their more immediate objectives.</p>
    </sec>
    <sec id="sec-3">
      <title>3. ONTOLOGY NEEDS</title>
      <p>
        In each of our projects, KR is tightly integrated into technical
research and development. We are working toward
semiautomated and automated resource discovery and integration,
including finding and merging heterogeneous datasets and
construction of workflows that pipe data through heterogeneous
computing environments [
        <xref ref-type="bibr" rid="ref4 ref5 ref6">4, 5, 6</xref>
        ]. We are also constructing
knowledge-driven rule-based systems. These applications require
high-quality ontologies and formal reasoning provided by
description logics for consistency checking and validation. Much
of the functionality provided by ontological reasoning will be
hidden from the user, yet will automate many low-level tasks that
the user would otherwise have to undertake manually.
Our ontology development has been two tiered: 1) development
of an upper-level structuring framework for observation and
measurements (core ontology), and 2) development of
domainspecific extensions to the core ontology. Our early work was
more focused on the first though the need for domain extensions
was known and information was continually gathered from the
community whenever possible. Recently, the core ontology has
been finalized and is currently being documented [
        <xref ref-type="bibr" rid="ref15">15</xref>
        ].
Scientists make observations about the world that are recorded as
measurements. The core ontology is the Extensible Observation
Ontology (OBOE), which is a formal and generic conceptual
framework for describing the semantics of observation and
measurement. The objective of OBOE was to separate knowledge
that is essential for describing observation and measurement from
knowledge that is asserted by a scientist and therefore a function
of opinion, interpretation, or even space and time. OBOE
requires that an observation is about an entity (concept or thing),
and a measurement is of a characteristic of the entity.
Measurement relates a value to a measurement standard as well
as an estimate about the confidence level of the value (e.g.,
measurement precision). OBOE prescribes a structured approach
for organizing domain-specific ontologies through the use of
“extension points,” i.e., specific classes, properties, and
constraints that are elaborated by different areas or views/models
of science. Therefore, OBOE can serve as an upper level
framework for defining new domain ontologies as well as
interoperating and relating existing domain ontologies.
While OBOE enforces a formal framework for describing the
semantics of observational data, extension of this framework with
domain ontologies requires the knowledge and experience of
domain scientists. The KR team is continually involved in
outreach to acquire community-based vocabularies and
informally-structured knowledge. These outreach activities
provide a flow of informally-structured semantic description
among collaborators (Figure 1).
Ultimately the knowledge resphreasreendtation team must make some
independent decisions about how best to model the domain within
a formal ontology. This, therefore, necessitates at least one and
perhaps many iterations of review by scientists. When the team
has an ontology ready for review, we would like to recruit people
from that domain to view it, comment, and propose changes.
While trees may be used effectively to review the hierarchical
structure, relationships are more difficult to communicate
effectively. They do not understand symbolic logic commonly
employed in editors. Usability testing of graphic visualizations
conducted by the SEEK project indicates that they are confusing
to domain users (Downey, personal communication).
Additionally, community-wide ontological commitment [
        <xref ref-type="bibr" rid="ref8">8</xref>
        ]
requires collective decision making, difficult to achieve without
synchronous communication. Currently, there is no obvious
mechanism by which to obtain the needed input from reviewers.
      </p>
    </sec>
    <sec id="sec-4">
      <title>4. USER SEMANTIC TASKS AND</title>
    </sec>
    <sec id="sec-5">
      <title>COMPUTER-SUPPORTED USE CASES</title>
      <p>There is a need for more collaboration between our KR team,
scientists, and information managers. The complexity of
ontologies and the difficulty of the knowledge modeling task
presents a daunting obstacle to those who are not familiar with
knowledge representation. We need tools that link knowledge
elicitation with tasks in which the community is already engaged,
and development of methods and tools that enable rapid mapping
from those to formal ontologies.</p>
      <p>
        There are many reasons to capture and represent knowledge in
science, separate and apart from the resource discovery and
integration goals of the Semantic Web. Smith [
        <xref ref-type="bibr" rid="ref23">23</xref>
        ] suggested that
oftentimes philosophers turn to science as a reliable way to learn
about the things and processes of a given domain. Much effort in
science is focused on acquiring knowledge through scientific
discourse. This begins during formal education but is ongoing
throughout the life of a scientist, who must be able to share his
own perspective and understand those of competing explanations.
Those semantic perspectives are implicit in the artifacts of
science: tools, models, datasets, and publications. Creation of
these artifacts involves tasks that are inherently semantic and
could both contribute to ontology development and be assisted by
a knowledge base. Here we provide four use cases of some
example tasks, knowledge-based computer support for those
tasks, and a vision for interaction mechanisms between and
among different stakeholders.
      </p>
    </sec>
    <sec id="sec-6">
      <title>4.1 Controlled vocabulary use case</title>
      <p>Karen Mann is an information manager for one of the LTER field
sites. She and several of her colleagues at other field sites have
decided to construct a standard set of terms and definitions to be
used as metadata keywords, to enable better data discovery by
scientists across the LTER network. She is aware of the
observation ontologies that are being developed, but doesn’t
really understand them. She is reluctant to attempt to make use of
an approach that she doesn’t understand. She does understand
that ontologies enable even better data discovery and integration
than her approach. Therefore, she wants to work within the
context of keywords and controlled vocabularies since that is
what she understands, but she would also like to link her list of
keywords to the ontology to take advantage of whatever
additional functionality is made available.</p>
      <p>
        Karen enters a website that provides an intuitive interface to a
knowledge base that holds many ontologies, both private and
shared. From this website she can create and manage her own
private knowledge base. She imports a list of terms that she has
previously generated. She can also import informal definitions
(not constrained logical definitions), or she can enter the
definitions on the website. Her colleagues import their lists into
their own private knowledge base as well. They all indicate to
the system that they want to share (or not) their private
knowledge bases. Karen selects her colleagues’ shared
knowledge bases from a list, generates a collaborative knowledge
base, and sends a message through the website asking them to
collaborate with her. From a collaboration screen, they are able
to merge their vocabulary lists into a single unfiltered list. The
system maintains a link between their individual lists and the
collective list, so that any changes made during collaboration can
optionally be copied back to their individual knowledge bases.
Their screens are linked. When one person selects or edits a term
everyone else’s screen automatically shows the change. They can
make use of VoIP or a chat window to discuss their vocabularies.
In this case, because there are a number of participants they prefer
to use chat [
        <xref ref-type="bibr" rid="ref14">14</xref>
        ]. Their chat session is recorded and at the end of
their discussion they can request for the chat session to be copied
to a blog attached to the collaborative knowledge base, providing
a permanent record.
      </p>
      <p>They collaboratively review duplicate terms and definitions to
determine semantic relationships. They identify synonyms and
can drag and drop synonyms on the screen so that they are
adjacent to one another. Where there are semantic conflicts they
resolve them and edit the collective vocabulary.</p>
      <p>Once they have a complete collective list of terms, they can
choose an option to annotate the terms in their list with an
ontology. A list of ontologies is provided to them, which includes
a list of “Our Favorite Ontologies” that the system generates from
each individual’s list of “My Favorite Ontologies.” They decide
on the ontologies they want to use (all of which are extensions to
the OBOE observation ontology), and begin to the annotation
process. For each term, the system automatically shows them
syntactically exact matches from their selected ontologies along
with definitions. They can easily explore parent, sibling, and
child concepts as well as other related concepts to ensure that they
understand the context of any given concept in the ontology and
to reconsider their term selection. They are able to search the
knowledge base using a google-style interface to see what other
concepts might be relevant. They can ask the system to analyze
their searches and suggest concepts based on the choices by other
users who have made similar searches. If they are uncertain about
whether a concept is appropriate, they can request several levels
of help: tips and tricks, online documentation of annotation
procedures, examples, live chat with a knowledge engineer, or
email support.</p>
      <p>If they do not find a concept that fits, they can suggest terms to be
added to the ontology. They recommend a concept and the
system provides them with a wizard to capture their
recommendations about where the concept belongs in the
ontology. The system allows them to go ahead and use the term
with a tentative annotation. Asynchronously, a knowledge
engineer will consider where to place the term in the ontology.
The system will provide him with information about the term
from their knowledge base and from their search history; he may
also request additional information from them. If he decides to
add the concept as suggested, the system makes any needed
adjustments to their knowledge base. If the concept is not added,
the knowledge engineer can identify it as a synonym or make
some other link from that term to the ontology such that the user
can continue to use that term but the system can resolve it to the
correct annotation. They will get automatic notification of the
final decision made by the knowledge engineer. Task support for
the knowledge engineer is further discussed in Section 4.4.
When Karen and her colleagues apply keywords to resources such
as datasets or publications, they each apply terms from their
individual controlled vocabulary. They can then select an option
for automatic annotation that runs a script that constructs the
correct ontological annotation. The metadata therefore includes
keywords from the local vocabulary and annotation to one or
more ontologies allowing the resources to be used with
ontologydriven discovery and integration tools.</p>
    </sec>
    <sec id="sec-7">
      <title>4.2 Data description use case</title>
      <p>John Green is an ecologist with LTER who collects field data on
plants. He has numerous spreadsheets with similar but slightly
varying schemas that he has collected over a number of years.
John is interested in contributing his data to a portal so that he can
participate in a new collaborative project that will analyze plant
species from around the globe. In order to do so, he must provide
metadata that includes ontological annotation.</p>
      <p>The LTER information managers have previously developed a
web application that walks users through the process of creating
metadata for datasets. Their knowledge base is accessed by this
application, providing access to the site’s controlled vocabulary
linked to ontologies. His information manager has provided some
training on how to make use of the application. John has never
actually used the system, but has a vague recollection of how to
do it and enters the website with confidence knowing that both the
description and annotation tasks are supported with intuitive user
interfaces online help for novices.</p>
      <p>John creates metadata for the first dataset. He loads the dataset
into the web application, which analyzes the dataset and is able to
automatically generate a fair amount of metadata. The system
prompts him for the remainder of the metadata. Then he must
begin the semantic annotation process. He starts with the
controlled vocabulary for his site. The system prompts him to
select keywords for the dataset as a whole, then for each attribute
in the dataset. Because the keywords are linked to an upper-level
ontology, the system prompts him to annotate the relationships
between attributes required by that ontology and guides him
through that task. If John has an attribute that he does not think is
adequately expressed by any of the terms in the controlled
vocabulary, he has all of the same ontology exploration
functionality available to the information managers. He can
suggest terms to be added to the controlled vocabulary and/or to
the ontology using the same procedure as the information
manager. In this case, his recommendation is forwarded to the
information manager who can assess the term, add it to the
controlled vocabulary and link it to the ontology, or forward it to
the knowledge engineer if it requires modification of the
ontology.</p>
      <p>Once the first dataset has been described and annotated, John has
several datasets that used the same schema. He loads the second
dataset and indicates to the system that it is a duplicate of the first
in terms of physical, logical, and semantic description. The
system analyzes both datasets using a metadata ontology and
verifies that that seems to be the case. The system duplicates the
metadata and annotations then prompts John for any edits that
might need to be made. The system “knows” which parts of the
metadata or annotations could possibly change because of the
existence of the metadata ontology and leads him through those.
If the datasets are not duplicates, the system will inform John
where there are discrepancies and support him through the
process of comparing datasets, resolving issues and generating
correct metadata and annotations.</p>
      <p>The remaining datasets are similar to the first dataset but vary in
different ways. John loads a new dataset into the tool and
indicates to the system that it is similar to the first dataset. The
system compares table structures, data types, and column content
and recognizes where there are differences. Again, the system
knows where metadata and annotations could possibly change,
and prompts John to enter the correct information.</p>
      <p>John wants to generate a template dataset that is already described
and annotated (to the extent possible) for future use. He can pick
any of the datasets already described and annotated, and request a
template. The system generates a blank table with associated
metadata and annotations, then prompts for other information that
is likely to be constant, such as project descriptions and
personnel. John can elect to fill these in automatically from the
original dataset or he can enter new information manually. Once
the template is finished, he can save it and easily generate new
datasets from it. Every time he does so, the system prompts him
for information that is collection-specific.</p>
      <p>Now that John has his datasets described and annotated, he
contributes them to the portal, which is also tied to the knowledge
base. He and a number of other scientists then begin to
collaboratively decide which data should be integrated. They
enter a web application that allows them to load up multiple
datasets and collectively discuss them. As with the information
managers, they can link their screens such that changes by one
person automatically appear on everyone else’s screen. They also
have chat, blog, and VoIP options. As they discuss the datasets
they are able to map between them semi-automatically using the
knowledge base and attribute annotations. They can modify any
of the mappings that the knowledge base suggests plus add new
mappings. They can generate integrated datasets based on their
mappings that inherit relevant metadata and annotations from the
source datasets, prompting them to complete whatever new
metadata or annotations are needed. As they collaboratively
decide on the mappings between datasets, the knowledge base
tracks their decisions. For instance, the scientists decide that
dataset 1 attribute 12 maps to dataset 2 attribute 6. These two
attributes were annotated differently and there currently is no
relationship between those concepts in the ontology. Through
their collaborative mapping, however, they have indicated that
there is indeed a relationship between these concepts. As they
work through semi-automatic mapping of many attributes from
many datasets the system is able to analyze their choices and
suggest changes to the ontology to the knowledge engineer.</p>
    </sec>
    <sec id="sec-8">
      <title>4.3 Concept mapping use case</title>
      <p>
        Through the data portal, John has begun a dialogue with several
scientists from different disciplines about potentially working
together on a research project. Because they are familiar with
different theories, research paradigms, and study methods, they
need to spend a significant amount of time developing a
conceptual framework that is well thought out and integrates their
different perspectives. They are located in different universities
and they can’t take enough time away from their teaching to
adequately develop a collaborative approach. They decide to
make use of a new web application that provides collaborative
concept mapping and is linked to the knowledge base.
They enter the website and rather than choose specific ontologies,
they select the portal and request to use the same ontologies as the
portal. Independently, they each draw concept maps and process
flow diagrams that represent their research interests. Each term
that they use, if present in the selected ontologies, is automatically
completed as they type it in. Again, if they want to use a term
that isn’t in the ontology they can suggest terms. The linkages
between terms in the diagram provide information about
relationships between concepts that the system tracks, analyzes,
and can use to suggest changes to the knowledge engineer.
Once they have each constructed their own diagrams they can
collaboratively view and discuss each others work using linked
screens, chat, blogs, and VoIP. They can draw diagrams together
representing their collective views. As they discuss the diagrams
they begin to resolve semantic issues. They determine that there
is a close relationship between certain concepts in their different
disciplines but they use different terminology for those concepts.
As they find these differences they draw links on their diagrams.
The system tracks these linkages and can use them to suggest
links across domain-specific extensions of the ontology.
They can request the system to “show datasets,” and next to each
term on their maps it will provide titles of datasets in the portal
that are annotated with that term or related terms. They can
explore these datasets in the same collaborative way as described
above, and construct integrated datasets. The portal is linked to a
repository of publications that have been annotated. Therefore
“show publications” can be used to display publications that have
been annotated with the terms related to those they have used.
After drawing many diagrams, exploring datasets, and reading
relevant publications they are ready to design their research
project. They make use of a “workflow design” module that
provides some structure for diagramming a conceptual scientific
workflow using concepts from the knowledge base. Each node in
the workflow represents a computational analysis or procedure
[
        <xref ref-type="bibr" rid="ref16">16</xref>
        ]. Links between the nodes represent flow of output data from
one component to input data for the next. They use terms from
model and process ontologies, with the system using automatic
word completion. They can indicate specific datasets from the
portal that are to be input to the workflow. When they are
satisfied with their workflow, they can export it as a beginning
workflow for a scientific workflow system and the annotations are
transferred with the workflow.
      </p>
    </sec>
    <sec id="sec-9">
      <title>4.4 Ontology review use case</title>
      <p>Bob Card is a knowledge engineer working with the LTER
community. He works on a tightly-coupled team that includes
both computer and domain scientists. Combining the teams’
collective knowledge with information from text mining he has
generated the knowledge base used in the above cases. He is
rapidly receiving input from all of the suggestions made by his
colleagues, as well as analysis of user actions from the system.
He needs some sort of semantic management system to help him
track all of these recommendations, make sense of them, and
generate automated response to users who are affected by a given
decision that he makes.</p>
      <p>He is able to generate term lists from any combination of the
above sources, flexibly sort and group terms, and try out tentative
hierarchical structures before making any changes to his formal
ontology. As he works with the tentative hierarchies he can invite
participants to collaborate with him using linked screens. Or, he
can request that colleagues review and modify a copy of any
tentative hierarchy. The system will compare the modified copy
with his tentative structure and show him where changes have
been proposed. At any point he can modify the tentative
ontology. When Bob is ready, he can request the system to align
his tentative ontology with the existing ontology and show
changes. When he is satisfied with the tentative ontology he can
“commit” it and the system will automatically replace the affected
portion of the existing ontology with the necessary changes. The
earlier version is stored in case he needs to return to it. The
system analyzes the changes and determines which annotated
resources are affected. It creates a new version of annotations for
those resources and notifies the user of the change.</p>
    </sec>
    <sec id="sec-10">
      <title>5. EXAMPLE COLLABORATION</title>
    </sec>
    <sec id="sec-11">
      <title>CENTERED SOLUTION</title>
      <p>Our team has started investigating technical solutions to the
challenge of defining user-friendly, semi-automated processes to
distill disciplinary knowledge into formal ontologies. Our goal is
to accomplish this with the least possible amount of difficulty for
the user and transparent, non-obtrusive involvement of the
knowledge base. The approach that we are taking is design of
interacting systems for knowledge base development and
management, community-based ontology interaction, and
multiple knowledge-based applications (Figure 2.).</p>
      <p>The ThinkCap Collaborative Knowledge Portal is a prototype
web application still under development that provides user
interfaces over a remote, multi-ontology knowledge base,
designed to meet the needs of both non-technical and technical
users (http://ecoinformatics.uvm.edu/technologies/thinkcap.html).
It aims to allow remote users of diverse disciplines and technical
levels to develop shared conceptualizations that are automatically
formalized into OWL or RDFS ontologies.</p>
      <p>The paradigm of knowledge elicitation being implemented in
ThinkCap uses a knowledge engineer in an asynchronous way; by
decoupling the formal knowledge base from the "arena" of user
discussion full concurrency of the editing of both is made
possible. The process is assisted by a full-text search engine that
indexes OWL concept descriptions as well as user-provided
documentation (such as web pages or academic papers).
We are currently extending ThinkCap to help such a diverse
community of users negotiate the rigorous, streamlined axioms in
an OWL knowledge space. A new collaborative portal in
ThinkCap will use a reasoner-assisted process and an upper
ontology to define different views of an OWL knowledge base.
These simplified views will allow applications to show only the
level of semantic complexity necessary for the immediate task.
Views will include conversion of ontologies to topic maps
(www.topicmaps.org). Topic maps reflect the knowledge in the
ontology base in ways that are much friendlier to the user
community and much easier to operate on concurrently. The
portal will provide a web-based whiteboard environment for
collaborative topic map editing. A reasoner-assisted listener
process will analyze user changes to the topic map and provide
suggestions to a knowledge engineer about possible relevance to
the underlying OWL axioms. Once a prototype has been tested
with users, we will design additional interfaces.</p>
      <p>OntoGrow is an interface to ThinkCap that is currently under
design. OntoGrow will provide functionality for communities to
interact with ThinkCap and can either be accessed directly or
indirectly through an application add-in. OntoGrow has three
objectives: 1) provide community feedback/critique of
ontologies, 2) recommend a term for an ontology, and 3) map
semantics between a resource and one or more ontologies. The
multiple views of ThinkCap will allow OntoGrow to provide
wizards that step a user through these processes in more intuitive
ways. For instance, to recommend a new term, the user could
first be asked to provide its definition through the dictionary view,
find a related term with a thesauri search, place the term in a
hierarchy by using a taxonomy to expose the context around the
related terms that the user has selected, and relate the term on a
topic map generated from the portion of the ontology that
includes that hierarchical element. Thus, the user can be stepped
through the task of ontology navigation by using their choices at
each point to simplify the choices at the next level of complexity.
The applications that are currently being developed by our
projects will each be able to make use of OntoGrow as an add-in
or through remote calls, providing a uniform mechanism of
interaction with the knowledge base. In addition, we are
designing a new system, SciDesign, that is envisioned to provide
the semantic-driven functionality described in our use cases.
SciDesign will provide an interface for knowledge-based
scientific discourse, resource discovery, exploration, and
management, and research design. As scientists and information
managers make use of SciDesign for individual or collaborative
efforts, their actions will be captured and analyzed by the system
and used to inform ontology development. Technical designs for
SciDesign, OntoGrow, and ThinkCap are currently being
developed under the second, implementation phase of complex
problem solving that follows idea generation.</p>
    </sec>
    <sec id="sec-12">
      <title>6. KNOWLEDGE ELICITATION</title>
    </sec>
    <sec id="sec-13">
      <title>CENTERED PROCESSES AND</title>
    </sec>
    <sec id="sec-14">
      <title>SOLUTIONS</title>
      <p>We present four approaches that our KR team has used to acquire
scientific knowledge, beginning with the least demanding for the
participants and ending with the most collaboration-intensive.
Each is followed by suggestions for incorporation of these tasks
into the proposed system.</p>
    </sec>
    <sec id="sec-15">
      <title>6.1 Text mining</title>
      <p>
        In science, the knowledge representation method of choice has
historically been written texts (publications) or conference
presentations with accompanying figures and tables. These
approaches are highly expressive and have worked well for
sharing scientific knowledge for generations. A wealth of
information about scientific concepts is locked up in textbooks
and publications. Effective mechanisms for mining these sources
provide abundant information for ontology development with no
additional effort on scientists’ parts. The downside of this
approach is that structure or presentation of knowledge within a
text represents the perspective of one or a few scientists, and does
not necessarily capture the perspective of the broader community.
It may not provide a knowledge model for which there can be
widespread ontological commitment [
        <xref ref-type="bibr" rid="ref8">8</xref>
        ]. Therefore, text mining
approaches are dependent on extensive collaborative review of
the results.
      </p>
      <p>
        The knowledge representation team is exploring different ways of
extracting knowledge from a popular ecological textbook [
        <xref ref-type="bibr" rid="ref3">3</xref>
        ] for
use in the OBOE framework. The team is quantifying the
strength of association among key ecological terms using various
measures of proximity. For example, the term “population” is
strongly associated with “individual” and also “community”;
however, the association between “individual” and “community”
is considerably weaker. Moreover, the proximity of different sets
of prepositions and verbs to coupled ecological terms is being
used as a mechanism to determine the most likely type of
relationship between terms. For example, when “individual” and
“population” are in close proximity, words like “in”, “part” and
“contain” are often also in close proximity suggesting a part-of
relationship between these terms. The team is also using book
chapter, section, and subsection headings to help structure the
nested ecological terms, which helps distill broader concepts in
the textbook domain (e.g., “competition” or “ecosystem”).
There are many mechanisms for incorporating text mining into
the hypothetical system. This functionality could be provided to
knowledge engineers within ThinkCap. Text mining could be
integrated into SciDesign as an aid for scientific literature search
and review. Substantial time is dedicated by scientists to
following the literature in their own discipline. Increasingly the
boundaries between disciplines must be crossed and scientists
must search for relevant literature in disciplines that are less well
known to them. Visual analytics is a new approach that mines
semantic content across many potential resources and provides
tools for visual content analysis [
        <xref ref-type="bibr" rid="ref25">25</xref>
        ]. Linking visual analytics
with text mining would provide scientists with functionality to
more easily, effectively, and comprehensively conduct literature
searches. Providing computer support that enables this task
would create an environment where it is to the scientist’s benefit
to use the system while providing valuable semantic information
for ontology development. In a given literature search, selection
of multiple resources from different disciplines, journals,
websites, and other online sources provides evidence that these
content sources are semantically related in some way. Combining
source-specific semantic keywords with the choices and actions
of many scientists equates to other forms of social tagging
prevalent in Web 2.0. The system should be equipped to analyze
these choices, mine the relevant texts, and both suggest other
literature that might be relevant to the scientist and in parallel,
propose terms and relationships to the knowledge engineer.
      </p>
    </sec>
    <sec id="sec-16">
      <title>6.2 Keywords and controlled vocabularies</title>
      <p>
        Scientist’s regularly apply keywords to textbooks, publications,
and datasets. Traditionally these are uncontrolled, though
controlled vocabularies are becoming more common (i.e. for
computer science publications IEEE and ACM share a definite
tree-structured list of terms). Additionally, the titles they choose
provide information about important terms. Mining titles and
keywords for concepts and relationships provides a pathway for
acquiring views on scientific knowledge that requires little effort
from scientists, but does require collaboration with information
managers who know how to access these on their systems.
Separate from our projects, LTER information managers
conducted a mining project on network datasets and publications
in order to develop a controlled vocabulary [
        <xref ref-type="bibr" rid="ref21">21</xref>
        ]. A list was
generated by compiling all words appearing in metadata titles,
keywords, and attributes, and in publication titles and keywords.
The resultant list contained 21,153 terms. The list was filtered for
‘of,’ ‘the,’ and similar definite articles and prepositions. Terms
were then rated in importance based on a number of usage
criteria. The information managers are continuing to work with
this list to develop a controlled vocabulary for use in tagging
datasets and publications. They provided this list to our KR team,
who were able to incorporate these terms into ontology
development. The intention of both groups is to ultimately link
the information managers’ controlled vocabularies to the ontology
such that controlled keywords applied to any resource are
automatically annotated to the ontology, the ontology can be used
to suggest terms that are not available in the controlled
vocabulary, and the process of users applying new keywords can
inform continued development of both the controlled vocabulary
and the ontology.
      </p>
      <p>In the proposed system, support for information management
activities could be embedded in SciDesign. One of the above use
cases explicitly addresses supporting construction and
management of local vocabularies. There are many other
information management activities that could be supported.
Sometimes these activities are conducted by information
managers, but there are many scientists who work independently
and must conduct these activities themselves. Even when
information managers are employed, they must work closely with
scientists. Design of functionality to assist information
management needs can be leveraged to support the activities of
the scientists.</p>
      <p>For instance, information managers collectively invest much
effort in designing databases, developing normalized schemas,
standardizing keywords, and developing standards for metadata.
They have their own knowledge arena that combines both generic
data management concepts and how those concepts are best
applied to a particular domain of interest. Separate ontologies
should be constructed to capture this knowledge. Rule-bases
could be constructed that link to those ontologies and can be used
to guide data management efforts. For instance, in designing a
new table for collection of a particular kind of field data, the
system could use an ontology and rules about database design to
provide expert advice and best practices, mine available data to
find and show examples of datasets that meet those guidelines and
are semantically equivalent to the data the scientist intends to
collect, and suggest one or more table designs.</p>
    </sec>
    <sec id="sec-17">
      <title>6.3 Concept mapping</title>
      <p>
        Concept mapping is an approach that the KR team has used that
provides direct input for ontology development from a number of
scientists while they are engaged in an activity that is useful to
them. Concept mapping is a representation mechanism that has
been developed to support a constructivist notion of learning [
        <xref ref-type="bibr" rid="ref18">18</xref>
        ].
Concept maps are a form of directed graph that captures
associations (links) between concepts (nodes; Figure 3). Concept
mapping provides maximum flexibility for conceptualization of a
domain of interest, and any kind of association can be mapped.
From a collaborative perspective, concept maps provide visual
representation of disparate conceptual frameworks including the
most important terms from a particular view, and places those
terms in context with one another for rapid understanding.
      </p>
      <p>
        The utility of concept maps as a mechanism for enabling
interdisciplinary discussion has been demonstrated [
        <xref ref-type="bibr" rid="ref11 ref13">11, 13</xref>
        ]. In
cross-disciplinary problem solving efforts, colleagues with
differing conceptual frameworks often have limited ability to
comprehend each other [
        <xref ref-type="bibr" rid="ref13 ref28 ref7">7, 28, 13</xref>
        ]. The degree to which
comprehension is limited depends on the conceptual proximity of
relevant conceptual frameworks - hence, two physical scientists
are more readily able to collaborate than a physical and social
scientist, or a life scientist and a computer scientist. Enabling
cross-disciplinary collaboration is therefore a problem of
representing disciplinary concepts in a way that enables rapid
comprehension and learning by those outside of that discipline
such that integrative problems can be solved.
      </p>
      <p>The process of concept mapping is analogous in many ways to
social tagging systems. The content, in this case, is an
unrepresented concept in the mind of the scientist. A node in a
concept map represents that concept. Two scientists may use
different terms in the node that describes that concept, essentially
tagging that concept differently. Links between nodes specify
that a relationship of some sort exists between those concepts.
This is roughly equivalent to inferring implicit semantic links
between Web content. Two scientists drawing concept maps
about the same research area will each have their own map using
the same or different terms and relationships, but they are tagging
the same semantic content. During scientific discourse, these
disparate concept spaces may become partially aligned. Hence,
concept maps from multiple scientists build a participatory
ecosystem of content that can provide important vocabulary,
indicate synonyms, show informal associations between terms,
and provide hierarchical relationships. These semantic tags
require structuring by the KR team and subsequent review and
editing for clearance, cohesion, and soundness. However, the
benefit of using concept maps is that it engages the scientific
community in supplying knowledge for ontology development in
a way that has other direct and immediate benefits to them, such
that they are more likely to participate.</p>
      <p>
        In the proposed system, concept maps and other diagrammatic
forms are expected to be an important part of SciDesign.
Scientists draw many sorts of diagrams and frequently find that
mode of expression useful while discussing complicated
crossdisciplinary subjects. Process diagrams, flow diagrams, project
diagrams – there are an unlimited number of uses of diagrams.
The system should provide flexible, intuitive diagramming tools
that can be collaboratively constructed and shared, plus easily
extracted and converted to publication-quality diagrams. If the
nodes on the diagrams are linked to ontologies they can provide
an individual “view” of the knowledge base, allowing each
scientist to maintain his own conceptual perspective without
compromising the collective formal structure. We have found
that it is important to the scientists to be able to express their
individual view with no constraints, and that the underlying
subsumption hierarchy is much less important to them [
        <xref ref-type="bibr" rid="ref20">20</xref>
        ].
Science is, after all, about investigating areas of our
understanding where there is not agreement, and understanding
linkages across hierarchies rather than within hierarchies. Much
of our analysis involves providing mechanisms for online and
collaborative construction of concept maps and other scientific
diagrams that facilitate working with different ‘views’ of a set of
ontologies based on individual perspectives and choices about
representation.
      </p>
    </sec>
    <sec id="sec-18">
      <title>6.4 Meeting with scientists</title>
      <p>
        The utility of ontologies has been introduced to scores of
ecologists during a week-long training workshop on
ecoinformatics that the SEEK project holds each January. The
participants in this training are 20 new faculty and postdoctoral
associates selected from on average 60-80 applicants from around
the US. The selected participants represent the most
technicallysavvy of young ecologists tackling problems that require
computational approaches. During the workshop, one full day is
spent covering ontologies. Over the four years that the training
has been conducted, the ontology portion has been constantly
modified based on feedback from students, and many new
approaches have been tried. In general, the students are exposed
to exercises that highlight the semantic issues in ecological
datasets and the requirements for resolving those issues. They
construct ontologies for their research interests on paper. We
demonstrate ontology editors and touch graph visualizations.
They step through portions of ontology editing exercises such as
CO-ODE’s pizza ontology [
        <xref ref-type="bibr" rid="ref12">12</xref>
        ]. The ontology portion of the
training is always the most difficult to present, and often receives
criticism in post-training surveys. Even though participants
understand the semantic issues and recognize that ontologies
might be useful for addressing them, they do not think that it is
important for them to understand ontologies. In the most recent
training (January 2007) survey feedback indicated that 50 percent
of participants, when asked what one thing they would change
about the training, thought the ontology portion should be
removed. This is a clear indication that direct exercises with
ontologies is an obscure task for ecological scientists and more
gentle tools are needed for communicating semantic models.
The KR team has attempted to engage groups of scientists in
ontology development through working meetings where they are
asked to talk about their research, explain terms, brainstorm
hierarchies, and provide lists of terms. Generally, their level of
interest in these activities fades rather rapidly, mirroring the
response from the training activities. Additionally, the
hierarchical structures that they propose are often unusable in our
ontologies due to logical errors. Most importantly, those who are
willing to participate are typically new faculty who are under
substantial pressure to produce research results quickly in order to
obtain tenure. Their modus operandi is to only get involved in
activities that will quickly lead to publication. Few obtain any
short-term professional benefit for assisting in the development of
ontologies; hence, few can remain engaged at the level needed.
Given all of these issues, the KR team has to be creative about
finding other ways to obtain their input. The hypothetical system
as a whole represents a new approach to “meeting with the
scientists.” This new approach is virtual rather than physical, and
focuses on linking user-centered task support with knowledge
development task needs. It combines “pulling” ontology
development through analysis of the way semantics are used by
the community with “pushing” ontology development with easy
mechanisms for reviewing and suggesting changes during task
performance. It is an attempt to solve the problems of disparity of
work and benefit, critical mass, and Prisoner’s dilemma [
        <xref ref-type="bibr" rid="ref10">10</xref>
        ] that
are prevalent in collaborative ontology development projects. It
does that by bridging the gap between formal and informal
semantic approaches in ways that reduces workload and provide
benefits for all participants.
      </p>
    </sec>
    <sec id="sec-19">
      <title>7. COLLABORATIVE ONTOLOGY</title>
    </sec>
    <sec id="sec-20">
      <title>DEVELOPMENT MODEL</title>
      <p>
        Developing semantic systems that depend on and enable group
sharing of resources differ in fundamental ways from developing
software that supports individuals and large organizations [
        <xref ref-type="bibr" rid="ref10">10</xref>
        ].
One clear difference is that in both of the latter, the tasks to be
supported are well-defined in advance by product managers or
inhouse IT experts, respectively. In contrast, semantic tasks may be
understood for the work of the KR team but are poorly defined for
any new community that is to be supported. For instance, much
work has been conducted on semantic tasks of online shoppers
and therefore systems that support and make use of these
activities are becoming common place. Those tasks are not
necessarily analogous in any way to the semantic tasks of a
completely different group such as scientists. The semantic tasks
must be understood before they can be supported. A second
difference is that the introduction of systems that drastically
change work patterns require corresponding investments in
dealing with social and political factors that go along with change
management. These issues are largely absent in development of
single-user software. They are strongly present in organizational
settings where there is also an infrastructure in place to provide
training, restructure work, and provide leadership. Our semantic
systems for scientists bring about all of the challenges of
changing work processes with little of the supporting
infrastructure. This is a common reason for failure of new
groupware solutions. For these reasons and many others it is
essential that collaborative knowledge development teams
become strategic in their activities. Unfortunately, there are few
models available to guide strategic choices.
      </p>
      <p>
        We propose the following model for development of semantic
systems that depend on collaboration between knowledge
representation specialists and the communities that they aspire to
support. System development should be explicitly divided into
two phases: an idea generation phase and an implementation
phase (Figure 4). The idea generation phase can be conceived of
as product development on steroids. It is separated out to
emphasize that this is a lengthy, time-consuming process that may
require as much resource investment as the implementation phase.
systems target. Developing cross-disciplinary understanding is
the first step towards the truly interdisciplinary perspective that is
required for effective idea generation. While there are few
theories about enabling interdisciplinary interaction, social
science research on boundaries, boundary crossing, and boundary
spanners point to the importance of constructing shared artifacts,
facilitated by an individual whose is explicitly tasked with
mediating between the groups [
        <xref ref-type="bibr" rid="ref13 ref2 ref24 ref30">24, 13, 30, 2</xref>
        ]. The role of a
mediator in any sort of groupware development is currently
unspecified but in the semantic system case, could include soft
system analysis of the KR team, domain specialists, and the
broader community.
      </p>
    </sec>
    <sec id="sec-21">
      <title>8. CONCLUSIONS</title>
      <p>This paper describes interactions that have taken place between a
knowledge representation team, natural scientists, and information
managers, and uses those to drive a set of use cases for design of
systems that enable better collaboration on ontology development.
Previous interactions have been stymied by the lack of
community understanding of ontologies and willingness to
dedicate time towards ontology development. These problems
reflect the lack of direct, immediate benefit for the participant.
Our experience leads us to believe that formal ontology
development could be more effectively informed by constructing
tools that capture semantic decisions that are made in the course
of the community’s everyday work. Our community of interest
regularly semantically tags the artifacts used in the conduct of
science – datasets, publications, and models, and makes use of
them in ways that capture semantic linkages. Design and
development of systems that capture these semantic decisions and
effectively make use of them to inform ontology development has
been initiated but is in its infancy. Ultimately, we hope to have
prototype systems and showcase applications that use those
systems to demonstrate the collective benefits of ontology-based
systems and applications.</p>
      <p>The ideas that are generated through this process are not a
complete set. They represent one or a few of many possible
integrated approaches to linking semantic tasks. As the ideas are
implemented and enacted within the broader community, other
ideas will emerge. It is extremely important that any strategy
taken explicitly account for feedbacks throughout the entire
process including providing mechanisms to incorporate the views
of the broader community in long-term system development.</p>
    </sec>
    <sec id="sec-22">
      <title>9. ACKNOWLEDGMENTS</title>
      <p>This work was funded through National Science Foundations
grant 0225665 for the SEEK project, grant DBI 0640837 for the
ARIES project, and European Union grant 010036-2 for
SEAMLESS. We would like to recognize the many relevant
discussions with the rest of the SEEK and ARIES teams, along
with valuable comments by anonymous reviewers that led to
restructuring of this paper and considerable sharpening of content.
Proceedings of the 38th Hawaii International Conference on
system Sciences.</p>
    </sec>
  </body>
  <back>
    <ref-list>
      <ref id="ref1">
        <mixed-citation>
          [1]
          <string-name>
            <surname>Athanasiadis</surname>
          </string-name>
          , IN (
          <year>2007</year>
          ).
          <article-title>Towards a virtual enterprise architecture for the environmental sector</article-title>
          , In: (Protogeros, N, Ed.)
          <article-title>Agent and Web Service Technologies in Virtual Enterprises</article-title>
          . Idea Group Inc.
        </mixed-citation>
      </ref>
      <ref id="ref2">
        <mixed-citation>
          [2]
          <string-name>
            <surname>Baker</surname>
            ,
            <given-names>KS</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Jackson</surname>
            ,
            <given-names>SJ</given-names>
          </string-name>
          , and
          <string-name>
            <surname>Wanetick</surname>
            ,
            <given-names>JR</given-names>
          </string-name>
          (
          <year>2005</year>
          ).
          <article-title>Strategies supporting heterogeneous data and interdisciplinary collaboration: Towards an ocean informatics environment,</article-title>
        </mixed-citation>
      </ref>
      <ref id="ref3">
        <mixed-citation>
          [3]
          <string-name>
            <surname>Begon</surname>
            ,
            <given-names>M</given-names>
          </string-name>
          , Townsend,
          <string-name>
            <given-names>C</given-names>
            , and
            <surname>Harper</surname>
          </string-name>
          ,
          <string-name>
            <surname>JL</surname>
          </string-name>
          (
          <year>2006</year>
          ). Ecology, Blackwell Publishing,
          <volume>752</volume>
          pp.
        </mixed-citation>
      </ref>
      <ref id="ref4">
        <mixed-citation>
          [4]
          <string-name>
            <surname>Berkley</surname>
            ,
            <given-names>C</given-names>
          </string-name>
          , Bowers,
          <string-name>
            <surname>S</surname>
          </string-name>
          , Jones,
          <string-name>
            <surname>M</surname>
          </string-name>
          , Ludaescher,
          <string-name>
            <given-names>B</given-names>
            ,
            <surname>Schildhauer</surname>
          </string-name>
          ,
          <string-name>
            <surname>M,</surname>
          </string-name>
          <article-title>and</article-title>
          <string-name>
            <surname>Tao</surname>
            ,
            <given-names>J</given-names>
          </string-name>
          (
          <year>2005</year>
          ).
          <article-title>Incorporating semantics in scientific workflow authoring</article-title>
          ,
          <source>Proceedings of the Statistical and Scientific Database Management (SSDBM</source>
          )
          <year>2005</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref5">
        <mixed-citation>
          [5]
          <string-name>
            <surname>Bowers</surname>
            ,
            <given-names>S,</given-names>
          </string-name>
          <article-title>and</article-title>
          <string-name>
            <surname>Ludaescher</surname>
            ,
            <given-names>B</given-names>
          </string-name>
          (
          <year>2004</year>
          ).
          <article-title>An ontology driven framework for data transformation in scientific workflows</article-title>
          ,
          <source>Proceedings of Data Integration for Life Sciences (DILS</source>
          )
          <year>2004</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref6">
        <mixed-citation>
          [6]
          <string-name>
            <surname>Bowers</surname>
            ,
            <given-names>S</given-names>
          </string-name>
          , Thau,
          <string-name>
            <surname>D</surname>
          </string-name>
          , Williams,
          <string-name>
            <given-names>R</given-names>
            , and
            <surname>Ludaescher</surname>
          </string-name>
          ,
          <string-name>
            <surname>B</surname>
          </string-name>
          (
          <year>2004</year>
          ).
          <article-title>Data procurement for enabling scientific workflows: On exploring inter-and parastism</article-title>
          ,
          <source>Proceedings of Semantic Web and Databases</source>
          (SWDB)
          <year>2004</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref7">
        <mixed-citation>
          [7]
          <string-name>
            <surname>Daily</surname>
            ,
            <given-names>GC</given-names>
          </string-name>
          and Ehrlich,
          <string-name>
            <surname>PR</surname>
          </string-name>
          (
          <year>1999</year>
          ).
          <article-title>Managing earth's ecosystems: an interdisciplinary challenge</article-title>
          ,
          <source>Ecosystems</source>
          <volume>2</volume>
          :
          <fpage>277</fpage>
          -
          <lpage>280</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref8">
        <mixed-citation>
          [8]
          <string-name>
            <surname>Davis</surname>
            ,
            <given-names>R</given-names>
          </string-name>
          , Shrobe,
          <string-name>
            <surname>H,</surname>
          </string-name>
          <article-title>and</article-title>
          <string-name>
            <surname>Szolovits</surname>
            ,
            <given-names>P</given-names>
          </string-name>
          (
          <year>1993</year>
          ).
          <article-title>What is a knowledge representation</article-title>
          ?
          <source>AI Magazine</source>
          <volume>14</volume>
          (
          <issue>1</issue>
          ):
          <fpage>17</fpage>
          -
          <lpage>33</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref9">
        <mixed-citation>
          [9]
          <string-name>
            <surname>DiCastri</surname>
            ,
            <given-names>F</given-names>
          </string-name>
          (
          <year>2000</year>
          ).
          <article-title>Ecology in a context of economic globalization</article-title>
          ,
          <source>BioScience</source>
          <volume>50</volume>
          (
          <issue>4</issue>
          ):
          <fpage>321</fpage>
          -
          <lpage>332</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref10">
        <mixed-citation>
          [10]
          <string-name>
            <surname>Grudin</surname>
            ,
            <given-names>J</given-names>
          </string-name>
          (
          <year>1994</year>
          ).
          <article-title>Groupware and social dynamics: eight challenges for developers</article-title>
          ,
          <source>Communications of the ACM</source>
          <volume>37</volume>
          (
          <issue>1</issue>
          ):
          <fpage>92</fpage>
          -
          <lpage>105</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref11">
        <mixed-citation>
          [11]
          <string-name>
            <surname>Heemskerk</surname>
            ,
            <given-names>M</given-names>
          </string-name>
          , Wilson,
          <string-name>
            <given-names>K</given-names>
            , and
            <surname>Pavao-Zuckerman</surname>
          </string-name>
          ,
          <string-name>
            <surname>M</surname>
          </string-name>
          (
          <year>2003</year>
          ).
          <article-title>Conceptual models as tools for communication across disciplines</article-title>
          ,
          <source>Conservation Ecology</source>
          <volume>7</volume>
          (
          <issue>3</issue>
          ):
          <fpage>8</fpage>
          -
          <lpage>17</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref12">
        <mixed-citation>
          [12]
          <string-name>
            <surname>Horridge</surname>
            ,
            <given-names>H</given-names>
          </string-name>
          , Knublauch,
          <string-name>
            <given-names>H</given-names>
            ,
            <surname>Rector</surname>
          </string-name>
          ,
          <string-name>
            <surname>A</surname>
          </string-name>
          , Stevens,
          <string-name>
            <surname>R</surname>
          </string-name>
          , and Wroe,
          <string-name>
            <surname>C</surname>
          </string-name>
          (
          <year>2004</year>
          ).
          <article-title>A Practical Guide To Building OWL Ontologies Using the Protégé-OWL Plugin and CO-ODE Tools, Edition 1.0</article-title>
          . Cooperative Ontologies Program tutorial,
          <volume>118</volume>
          pp. Available at http://www.coode.org/resources/tutorials/ProtegeOWLTutorial.pdf.
        </mixed-citation>
      </ref>
      <ref id="ref13">
        <mixed-citation>
          [13]
          <string-name>
            <surname>Jeffrey</surname>
            ,
            <given-names>P</given-names>
          </string-name>
          (
          <year>2003</year>
          ).
          <article-title>Smoothing the waters: observations on the process of cross-disciplinary research collaboration</article-title>
          ,
          <source>Social Studies of Science</source>
          <volume>33</volume>
          (
          <issue>4</issue>
          ):
          <fpage>539</fpage>
          -
          <lpage>562</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref14">
        <mixed-citation>
          [14]
          <string-name>
            <surname>Löber</surname>
            ,
            <given-names>A</given-names>
          </string-name>
          , Schwabe,
          <string-name>
            <surname>G</surname>
          </string-name>
          , Grimm,
          <string-name>
            <surname>S</surname>
          </string-name>
          (
          <year>2007</year>
          ).
          <article-title>Audio vs. chat: The effects of group size on media choice</article-title>
          .
          <source>Proceedings of the 40th HICCS Hawaii International Conference on System Sciences.</source>
        </mixed-citation>
      </ref>
      <ref id="ref15">
        <mixed-citation>
          [15]
          <string-name>
            <surname>Madin</surname>
            ,
            <given-names>J</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Bowers</surname>
            ,
            <given-names>S</given-names>
          </string-name>
          , Schildhauer,
          <string-name>
            <surname>M</surname>
          </string-name>
          , Krivov,
          <string-name>
            <surname>S</surname>
          </string-name>
          , Pennington,
          <string-name>
            <given-names>D</given-names>
            , and
            <surname>Villa</surname>
          </string-name>
          ,
          <string-name>
            <surname>F</surname>
          </string-name>
          <article-title>(in review). An ontology for describing and synthesizing ecological observation data</article-title>
          . Submitted to International
          <source>Journal of Ecological Informatics.</source>
        </mixed-citation>
      </ref>
      <ref id="ref16">
        <mixed-citation>
          [16]
          <string-name>
            <surname>Michener</surname>
            ,
            <given-names>WK</given-names>
          </string-name>
          , Beach,
          <string-name>
            <given-names>JH</given-names>
            , Jones, M.B,
            <surname>Ludaescher</surname>
          </string-name>
          ,
          <string-name>
            <surname>B</surname>
          </string-name>
          , Pennington,
          <string-name>
            <surname>DD</surname>
          </string-name>
          , Pereira,
          <string-name>
            <surname>RS</surname>
          </string-name>
          , Rajasekar,
          <string-name>
            <given-names>A</given-names>
            , and
            <surname>Schildhauer</surname>
          </string-name>
          ,
          <string-name>
            <surname>M</surname>
          </string-name>
          , (
          <year>2007</year>
          ).
          <article-title>A knowledge environment for the biodiversity and ecological sciences</article-title>
          .
          <source>Journal of Intelligent Information Systems DOI</source>
          <volume>10</volume>
          .1007/s10844-006-0034-8 available online at url: http://www.springerlink.com/content/e252n818242783g4/.
        </mixed-citation>
      </ref>
      <ref id="ref17">
        <mixed-citation>
          [17]
          <string-name>
            <surname>Newell</surname>
            ,
            <given-names>B</given-names>
          </string-name>
          , Crumley,
          <string-name>
            <surname>CL</surname>
          </string-name>
          , Hassan,
          <string-name>
            <surname>N</surname>
          </string-name>
          , Lambin,
          <string-name>
            <surname>EF</surname>
          </string-name>
          , PahlWostl, C, Underdal,
          <string-name>
            <surname>A</surname>
          </string-name>
          , Wasson,
          <string-name>
            <surname>R</surname>
          </string-name>
          (
          <year>2005</year>
          ).
          <article-title>A conceptual template for integrative human-environment research</article-title>
          ,
          <source>Global Environmental Change</source>
          <volume>15</volume>
          :
          <fpage>299</fpage>
          -
          <lpage>307</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref18">
        <mixed-citation>
          [18]
          <string-name>
            <surname>Novak</surname>
            ,
            <given-names>JD</given-names>
          </string-name>
          , and
          <string-name>
            <surname>Wurst</surname>
          </string-name>
          , M (
          <year>2005</year>
          ).
          <article-title>Collaborative knowledge visualization for cross-community learning</article-title>
          , In: (Tergan, S and Keller, T Eds.)
          <source>Knowledge and Information Visualization, Lecture Notes in Computer Science</source>
          <volume>3426</volume>
          :
          <fpage>95</fpage>
          -
          <lpage>116</lpage>
          , Berlin Heidelberg: Springer-Verlag.
        </mixed-citation>
      </ref>
      <ref id="ref19">
        <mixed-citation>
          [19]
          <string-name>
            <surname>Noy</surname>
            ,
            <given-names>NF</given-names>
          </string-name>
          , Sintek,
          <string-name>
            <surname>M</surname>
          </string-name>
          , Decker,
          <string-name>
            <surname>S</surname>
          </string-name>
          , Crubezy,
          <string-name>
            <surname>M</surname>
          </string-name>
          , Fergerson,
          <string-name>
            <surname>RW</surname>
          </string-name>
          , and Musen, MA (
          <year>2001</year>
          ).
          <article-title>Creating semantic web content with Protégé-2000, Intelligent Systems 16(2</article-title>
          ):
          <fpage>60</fpage>
          -
          <lpage>71</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref20">
        <mixed-citation>
          [20]
          <string-name>
            <surname>Pennington</surname>
            ,
            <given-names>D</given-names>
          </string-name>
          (
          <year>2006</year>
          ).
          <article-title>Representing the dimensions of an ecological niche</article-title>
          .
          <source>Proceedings 5th International Semantic Web Conference (ISWC'06) Workshop: Terra Cognita</source>
          <year>2006</year>
          - Directions to the
          <source>Geospatial Semantic Web, November</source>
          <volume>6</volume>
          ,
          <year>2006</year>
          , Athens, Georgia. Available online: http://www.ordnancesurvey.co.uk/oswebsite/partnerships/res earch/research/terracognita.html.
        </mixed-citation>
      </ref>
      <ref id="ref21">
        <mixed-citation>
          [21]
          <string-name>
            <surname>Porter</surname>
            ,
            <given-names>J</given-names>
          </string-name>
          (
          <year>2006</year>
          ).
          <article-title>Improving data queries through use of a controlled vocabulary, DataBits: An Electronic Newsletter for Information Managers</article-title>
          ,
          <year>Spring 2006</year>
          . Available online: http://intranet.lternet.edu/archives/documents/Newsletters/Da taBits/06spring/.
        </mixed-citation>
      </ref>
      <ref id="ref22">
        <mixed-citation>
          [22]
          <string-name>
            <surname>Rizzoli</surname>
            ,
            <given-names>AE</given-names>
          </string-name>
          , Donatelli,
          <string-name>
            <surname>M</surname>
          </string-name>
          , Athanasiadis, IN, Villa,
          <string-name>
            <given-names>F</given-names>
            , and
            <surname>Huber</surname>
          </string-name>
          , D (accepted).
          <article-title>Semantic links in integrated modeling frameworks</article-title>
          ,
          <source>Mathematics and Computers in Simulation.</source>
        </mixed-citation>
      </ref>
      <ref id="ref23">
        <mixed-citation>
          [23]
          <string-name>
            <surname>Smith</surname>
            ,
            <given-names>B</given-names>
          </string-name>
          (
          <year>2003</year>
          ).
          <article-title>Ontology: An introduction</article-title>
          . In: (Floridi, L ed.), Blackwell Guide to the
          <source>Philosophy of Computing and Information</source>
          . Oxford:Blackwell, pp.
          <fpage>155</fpage>
          -
          <lpage>166</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref24">
        <mixed-citation>
          [24]
          <string-name>
            <surname>Star</surname>
            ,
            <given-names>SL</given-names>
          </string-name>
          (
          <year>1990</year>
          ).
          <article-title>The structure of ill-structured solutions: boundary objects and heterogeneous distributed problem solving</article-title>
          . In: (L. Gasser and EMN Huhns, Eds.)
          <source>Distributed Artificial Intelligence</source>
          , Vol.
          <volume>2</volume>
          . London: Morgan Kaufmann Publishers, Inc., pp.
          <fpage>35</fpage>
          -
          <lpage>54</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref25">
        <mixed-citation>
          [25]
          <string-name>
            <surname>Thomas</surname>
            ,
            <given-names>JJ</given-names>
          </string-name>
          and Cook,
          <string-name>
            <surname>KA</surname>
          </string-name>
          (
          <year>2006</year>
          ).
          <article-title>A visual analytics agenda</article-title>
          ,
          <source>IEEE Computer Graphics and Applications</source>
          <volume>26</volume>
          (
          <issue>1</issue>
          ):
          <fpage>10</fpage>
          -
          <lpage>13</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref26">
        <mixed-citation>
          [26]
          <string-name>
            <surname>Villa</surname>
            ,
            <given-names>F</given-names>
          </string-name>
          , and
          <article-title>Athanasiadis</article-title>
          , IN (submitted).
          <article-title>Modelling with knowledge: Emerging semantic approaches to ecological modeling, Ecological Modelling</article-title>
          .
        </mixed-citation>
      </ref>
      <ref id="ref27">
        <mixed-citation>
          [27]
          <string-name>
            <surname>Vincent</surname>
            ,
            <given-names>AS</given-names>
          </string-name>
          , Decker,
          <string-name>
            <given-names>BP</given-names>
            , and
            <surname>Mumford</surname>
          </string-name>
          , MD (
          <year>2002</year>
          ).
          <article-title>Divergent thinking, intelligence, and expertise: A test of alternative models</article-title>
          ,
          <source>Creativity Research Journal</source>
          <volume>14</volume>
          (
          <issue>2</issue>
          ):
          <fpage>163</fpage>
          -
          <lpage>178</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref28">
        <mixed-citation>
          [28]
          <string-name>
            <surname>Wear</surname>
            ,
            <given-names>DN</given-names>
          </string-name>
          (
          <year>1999</year>
          ).
          <article-title>Challenges to interdisciplinary discourse</article-title>
          ,
          <source>Ecosystems</source>
          <volume>2</volume>
          :
          <fpage>299</fpage>
          -
          <lpage>301</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref29">
        <mixed-citation>
          [29]
          <string-name>
            <surname>Welp</surname>
            , M
            <given-names>A</given-names>
            , de la Vega-Leinert, A
          </string-name>
          ,
          <string-name>
            <surname>Stoll-Kleemann</surname>
            ,
            <given-names>S</given-names>
          </string-name>
          , and Jaeger,
          <string-name>
            <surname>CC</surname>
          </string-name>
          (
          <year>2006</year>
          ).
          <article-title>Science-based stakeholder dialogues: Theories and tools</article-title>
          ,
          <source>Global Environmental Change</source>
          <volume>16</volume>
          :
          <fpage>170</fpage>
          -
          <lpage>181</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref30">
        <mixed-citation>
          [30]
          <string-name>
            <surname>Williams</surname>
            ,
            <given-names>P</given-names>
          </string-name>
          (
          <year>2002</year>
          ).
          <article-title>The competent boundary spanner</article-title>
          ,
          <source>Public Administration</source>
          <volume>80</volume>
          (
          <issue>1</issue>
          ):
          <fpage>103</fpage>
          -
          <lpage>124</lpage>
          .
        </mixed-citation>
      </ref>
    </ref-list>
  </back>
</article>