In this paper we introduce the Publishing Work ow Ontology (PWO), i.e., an OWL 2 DL ontology for the description of generic work ows that is particularly suitable for formalising typical publishing processes such as the publication of articles in journals. We support the presentation with a discussion of all the ontology design patterns that have been reused for modelling the main characteristics of work ows.
Keeping track of publication processes is a crucial task for publishers. This activity allows them to produce statistics on their goods (e.g., books, authors, editors) and to understand whether and how their production changes over time. Organisers of particular events, such as academic conferences, have similar needs. Tracking the number of submissions in the current edition of a conference, the number of accepted papers, the review process, etc., are important statistics that can be used to improve the review process in future editions of the conference.
Some communities have started to publish data, e.g., the Semantic Web Dog Food5 and the Semantic Web Journal6, which describe those scholarly data as RDF statements in the Linked Data, in order to allow software agents and applications to check and reason on them, and to infer new information. However, the description of processes, for instance the peer-review process or the publishing process, is something that is not currently handled { although sources of related raw data exist (e.g., EasyChair metadata). Furthermore, having these types of data publicly available would increase the transparency of the aforementioned processes and allow their use for statistical analysis. Of course, a model for describing these data is needed. Moreover, the model should be easy to integrate and adapt according to the needs and constraints of di erent domains (publishing, academic conferences, research funding, etc.).
In this paper we introduce the Publishing Work ow Ontology (PWO), that we developed in order to accommodate the aforementioned requirements. This ontology is one of the Semantic Publishing and Referencing (SPAR) Ontologies7 (which have been created for the description of di erent aspects of the publishing domain), and allows one to describe the logical steps in a work ow, as for example the process of publication of a document. Each step may involve one or more events that take place at a particular phase of the work ow (e.g., authors are writing the article, the article is under review, a reviewer suggests to revise the article, the article is in printing, the article has been published, etc.). This ontology has been developed in order to allow its use with other SPAR Ontologies as well as other models and existing data.
The rest of the paper is organised as follows. In Section 2 we discuss some related works on work ows within the Semantic Web domain. In Section 3 we provide the de nitions of work ow we have used as starting point for modelling our ontology, and discuss the use of some existing ontology design patterns for addressing the modelling issues related to the main characteristics of work ows. In Section 4 we introduce PWO, describing how it extends the aforementioned patterns in order to handle the main components of work ows, and we support the discussion by means of a real example of publication process of an article of the Semantic Web Journal. Finally, in Section 5 we conclude the paper sketching out some future works. 2
In the last years the Semantic Web community have started on working and
proposing models for the formalisation and description of generic work ows, and
have shown several applications of these models/theories within the publishing
domain. Maybe the rst huge-impact project on these topic has been Work ow
4ever (STREP FP7-ICT-2007-6 270192)8 [
As already stated, one of the outcomes of the project has been the proposal
for work ow-centric Research Objects [
Another interesting proposal for describing work ows is the work done by
Garijo and Gil [
Finally, among the other proposals for describing work ows, it worths
mentioning the OWL ontology proposed by Sebastian et al. [
In order to design an ontology for modelling (publishing) work ows, we have to understand what are the minimal characteristics that such ontology should address and if we can reuse some existing modelling solutions. Oxford Dictionaries de nes work ow as follows: \The sequence of industrial, administrative, or other processes through which a piece of work passes from initiation to completion."15
From this de nition it is possible to identify some important characteristics of any work ow, i.e., the fact that it involves a sequence of processes that allow to initiate and then complete a piece of work during a speci able time interval. The de nition of the SearchCIO website is still more speci c: \Work ow is a term used to describe the tasks, procedural steps, organizations or people involved, required input and output information, and tools needed for each step in a business process."16
From this de nition we can spot other crucial aspects. First of all, its structural organisation in procedural steps, each of them describes tasks performed by organisations and people, and each step requires some input information and tools in order to produce an output. Using these two de nition as input, we 11 Open Provenance Model for Work ows: http://www.opmw.org/ontology/. 12 Ontology for Provenance and Plans: http://purl.org/net/p-plan#. 13 http://ns.taverna.org.uk/2010/scu 2 14 http://www.taverna.org.uk 15 http://www.oxforddictionaries.com/de nition/english/work ow 16 http://searchcio.techtarget.com/de nition/work ow can identify some well-known ontological patterns that already address, from an abstract point of view, some of the aspects related of work ows.
Participation. The participation pattern17 is a simple pattern that allows us to describe processes, events, or states (through the class Event), and to specify the various objects (through the class Object) that participate in these events.
This pattern seems to be very useful to de ne work ows as events involving people, organisations, places, and other objects as participants, as well as to link work ows and related activities to the expected steps .
Sequence. The sequence pattern18 is another pattern that can be used between tasks, processes or time intervals, in order to de ne sequences of such objects through direct (i.e., directlyFollows and directlyPrecedes) and transitive relations (i.e., follows and precedes). It is, of course, very useful to describe the logical organisation of the various steps of a work ow.
Control ow and plan execution. The control ow pattern19 is an OWL
representation of some of the constructs de ned in the Work ow Patterns20 by
Wil van der Alst (cf. [
These patterns are of course, very useful to describe the kinds of steps (the term used here for tasks) in a work ow and in general in publishing work ows. The action and control tasks from the control ow pattern are not specialised in the publishing work ow pattern, because they are expected to work as they are (by typing the steps according to their work ow semantics) when the need for control ows emerges in a planned work ow.
Time-indexed situation. The time-indexed situation pattern23 allows the description of a situation (i.e., the class TimeIndexedSituation) { i.e., a view on a set of entities linked to it through the property isSettingFor { that is explicitly indexed at some time speci able through the property atTime linking a time interval (i.e., an instance of the class TimeInterval).
This pattern can be used to describe steps from an abstract point of view as kinds of situations representing the settings for all the events and input/output material needed or produced by these steps. Notice that time-indexed situation combines perfectly with plan execution in order to provide a temporal ordering to activities organised into a plan. 17 http://www.ontologydesignpatterns.org/cp/owl/participation.owl 18 http://www.ontologydesignpatterns.org/cp/owl/sequence.owl 19 http://www.ontologydesignpatterns.org/cp/owl/control ow.owl 20 The Work ow Patterns page is: http://www.work owpatterns.com. 21 http://www.ontologydesignpatterns.org/cp/owl/basicplandescription.owl 22 http://www.ontologydesignpatterns.org/cp/owl/basicplanexecution.owl 23 http://www.ontologydesignpatterns.org/cp/owl/timeindexedsituation.owl
Error Ontology. The Error Ontology24 is a unit test that produces an
inconsistent model if a particular (and incorrect) situation happens. It works by
means of a data property, error:hasError, that denies its usage for any resource,
as shown as below (in Manchester Syntax [
Domain : error : hasError exactly 0
Range : xsd : string
A resource that has an error makes the ontology inconsistent, since its domain is \all those resources that do not have any error:hasError assertion".
This model is very useful in our context in order to de ne constraints on the input/output objects needed by the steps of a work ow. For instance, we could use it to deny the use of a certain object as input of a step if it will be produced only as output of one of the following steps. 4
In order to accommodate work ow requirements, we developed the Publishing Work ow Ontology25 (PWO), which is entirely based on the ontology patterns introduced in Section 3. This ontology allows one to describe the logical steps in a work ow, as for example the process of publication of a document. Each step may involve one or more events (or actions) that take place to a particular phase of the work ow (e.g., authors are writing the article, the article is under review, a reviewer suggests to revise the article, the article is in printing, the article has been published, etc.).
As shown in Fig. 1, PWO is based on two main classes, which are: { class pwo:Work ow. It represents a sequence of connected tasks (i.e., steps) undertaken by the agents; it is a subclass of plan:PlanExecution26; { class pwo:Step. It is an atomic unit of a work ow, subclass of taskrole:Task; it is characterised by a (required) starting time and an ending time, and it is associated with one or more events (activities) that are executed within the step. A work ow step usually involves some input information, material or energy needed to complete the step, and some output information, material or energy produced by that step. In the case of a publishing work ow, a step typically results in the creation of a publication entity, usually by the modi cation of another pre-existing publication entity, e.g., the creation of an edited paper from a rough draft, or of an HTML representation from an XML document. 24 http://www.essepuntato.it/2009/10/error 25 http://purl.org/spar/pwo 26 Note that in PWO we are not using explicitly the separation between work ow de nition and work ow execution, since PWO has been thought as an ontology to provide a retrospective description of running work ows. Even if this is a simplication of the whole approach described by the imported patterns, we decided to include both patterns for work ow de nition and execution in order to handle even work ow de nitions in case we may need it (even if we have not yet explored this use of PWO properly).
PWO was implemented according to the aforementioned ontology patterns. As shown in Table 1, such patterns have been used as follows: { plan execution to describe work ows as plans, and their executions; { time-indexed situation to describe work ow steps as entities that involve a duration and that are characterised by events and objects (needed for and produced by the step); { sequence to de ne the order in which steps appear within a work ow; { control ow to describe the specialization and nature of steps at planning time; { participation to describe events (and eventually agents involved) taking part in the activities carried out according to the steps.
In addition, by means of the Error Ontology, we can generate an inconsistency
every time the steps of a work ow are not arranged in a correct temporal order.
In particular, an error is raised when a step requires (property pwo:needs) to use
a particular object that will be produced (property pwo:produces) as consequence
of another sequent step. The following excerpt shows the implementation of this
constraint through a SWRL rule [
In the next subsections we show how to describe the process of publication
of a journal article step by step. In particular we introduce how PWO can be
used in combination with existing data of the Semantic Web Journal27 [
From a pure publisher's perspective, the rst step of any work ow that brings to a new journal publication starts with a formal submission of a manuscript performed by someone, hereinafter the author. This activity expresses, at the same time, interest on the topics of the journal and may acknowledge, indirectly, the quality of the journal itself { since authors (usually) would like to publish articles in a venue that they consider respectful and qualitatively worth for di erent reasons (e.g., quality of reviews, journal impact factor, de nite timing of the publishing process). Then, in the next step, i.e., the reviewing phase, the person (designated by the publisher) in charge of the quality of submitted material, hereinafter the editor, invites other people (hereinafter the reviewers) for assessing the quality of the submitted manuscript. The opinions returned by the reviewers to the editor are the fundamental input that the editor will use to decide upon the fate of the manuscript during the next step, i.e., the decision phase. Finally, if the manuscript have been considered worth of publication in the present form, the editor will acknowledge the author of the acceptance of his/her work { and the next steps of the work ow will be in charge of the publisher itself. Otherwise, if the article is not ready for being published, the editor either may ask for its rejection, thus nishing the work ow, or (s)he can return a list of issues to be addressed to the author in order to deserve publication. In this latter case, the revision phase will start and the author will revise the paper according to reviewers' comments and editor's suggestions, and thus the work ow will continue with a new submission phase.
The whole publishing work ow we have described (summarised in Fig. 2) can
be formally represented by means of PWO. In the following excerpt (in Turtle
[
In the next sections we show how to describe the rst four steps of such
work ow by taking into account real publication data available in the Semantic
Web Journal Linked Data repository concerning [
The rst step of the work ow concerned the submission of a manuscript by one
of its authors, in this case Paolo Ciccarese. Thus, the manuscript received the
status of \submitted" and it was made available to the journal editor and the
reviewers for the next step of the work ow. In order to describe all these aspects
concerning the rst step, we use several entities de ned in the ontology patterns
imported by PWO, as well as a number of other entities from another SPAR
ontology, i.e., the Publishing Status Ontology (PSO)29 [
The step regarding the reviewing phase began with the activity of the editor,
Giancarlo Guizzardi, of looking for appropriate reviewers for the paper. Once
found, the reviewers were provided with the manuscript, reviewed it, and wrote
down their comments that were nally sent back to the editor. In order to
describe all the aspects concerning the second step, we use several entities de ned
in additional SPAR ontologies, i.e., the Citation Counting and Context
Characterisation Ontology (C4O)30 [
ti : hasIntervalStartDate "2013 -04 -01 T05 :53:24"^^ xsd : dateTime ] . 4.4
During the third step, the editor was responsible for the fate of the paper and provided a decision for it according to reviewers' comments. Once formalised the decision, a decision letter was sent by email to the corresponding author (i.e., Paolo Ciccarese) and the status of the paper changed in then in \minor revision". In the following excerpt we introduce the formalisation in PWO of the third step of the work ow: During the fourth step, the authors worked in order to revise the content of the previous version of the paper according to reviewers' comments and editor's suggestions. At the end of this step, the main result was the creation of a new version of the paper (i.e., swj-node:506 in our example) that had to be submitted in the next step. In the following excerpt we introduce the formalisation in PWO of the fourth step of the work ow: : step - four a pwo : Step ; pwo : hasNextStep : step - five ; # Revision step pwo : involvesAction : revision - action ; tisit : atTime [ a ti : TimeInterval ; ti : hasIntervalStartDate "2013 -06 -10 T17 :47:53"^^ xsd : dateTime ; ti : hasIntervalEndDate "2013 -07 -01 T05 :51:30"^^ xsd : dateTime ] ; pwo : needs swj - node :432 , : decision - letter , : review -1 , : review -2 ; pwo : produces swj - node :506 . : revision - action a taskex : Action ; dcterms : description " The authors revises the paper " ; part : hasParticipant swj - node :432 , : decision - letter ,
: review -1 , : review -2 , swj : silvio - peroni , swj : paolo - ciccarese . 5
In this paper we introduced the Publishing Work ow Ontology (PWO), i.e., an
OWL 2 DL ontology part of the Semantic Publishing and Referencing (SPAR)
Ontologies, which allows the description of publishing work ows in RDF. The
whole ontology is entirely based on existing ontology design patterns that allowed
us to model the various aspects of work ows in an appropriate and standardised
way. We showed a particular use of PWO for describing the rst steps of a real
publishing work ow concerning the publication of an article of the Semantic
Web Journal, i.e., [
Although PWO had been thought in principle to describe publishing-related work ows, it has been developed on purpose as an ontology for the description of generic work ows. In future we plan to align it to other work ow-related models, e.g., PROV-O, the Research Object ontology and the other ontologies described in Section 2. In addition, we are currently studying the applicability of PWO in the legal and scienti c domains. In particular, we plan to work on its use for describing work ows that concern the process of codi cation of the laws of the United States legislation and the series of computational or data manipulation steps in scienti c applications.