Anniken Karlsen

Enterprise modeling practice in ICT-enabled process change

Keywords: Enterprise modeling, modeling tools, modeling use, barriers to modeling. 2 Motivation

This paper presents and discusses findings from a study where the use of enterprise modeling has been empirically investigated in eight combined process change and information technology initiatives. Artifacts, guidelines and tools used in enterprise modeling practice are identified. We identify three types of barriers to enterprise modeling: Challenges, Resistance and Moderators. We compare the way the modeling activities are organized with modeling maturity of different groups of project stakeholders. Our results indicate that the distribution of modeling maturity between project stakeholders affects how the modeling activities are carried out.

Introduction

Enterprise modeling can be seen as the art of externalizing knowledge which adds value to the enterprise or needs to be shared, and are often, as done in the following, used as a catch-all title to describe the activity of modeling any pertinent aspect of an organization [START_REF] Fraser | Managing Change through Enterprise models[END_REF]. Enterprise modeling can be used to represent the structure, behavior, components and operations of a business entity to understand, (re)engineer, evaluate, optimize and control business operations and performance [START_REF] Vernadat | Enterprise Modeling and Integrations, principles and applications[END_REF][START_REF] Miles | Qualitative data analysis -an expanded sourcebook[END_REF].

There are many commercial tools which have come into the marketplace in recent years to assist with architecture visualization and modeling [START_REF] Nightingale | Enterprise Systems Architecting: Emerging Art and Science within Engineering Systems[END_REF]. Persson and Stirna [START_REF] Persson | Why Enterprise Modelling? An Explorative Study into Current Practice[END_REF] emphasize that while much research has been done on developing enterprise modeling methods, research concerning enterprise modeling in practice has been more or less neglected by the research community. A similar situation can be seen within process modeling, which can be seen as a specialized field of enterprise modeling [START_REF] Andersen | Enterprise Modeling for Business Process Improvement[END_REF]. Sedera, Gable, Rosemann and Smyth [START_REF] Sedera | A success modell for business process modeling: findings from a multiple case study[END_REF] emphasize that while there has been much research on process modeling techniques and corresponding tools, there has been little empirical research into important factors of effective process modeling and post-hoc evaluation of process modeling success.

This paper presents findings from a multiple case study of enterprise modeling practice in ICT-enabled process change. The paper supplements another publication where it is shown that different types of modeling initiatives produce a broad variety of modeling benefits [START_REF] Karlsen | Benefits of different types of enterprise modeling initiatives in ICT-enabled process change[END_REF]. The paper provides insight and answers to the following research questions:

(1) How is the modeling process organized?

(2) How is participation and involvement in the modeling process?

(3) Which tools, languages and guidelines are used for modeling? (4) Which artifacts are produced in each type of modeling initiative? [START_REF] Vernadat | Enterprise Modeling and Integrations, principles and applications[END_REF] What might influence the selected way of organizing the modeling process as for example workshops with oral participation or workshops with active participation? [START_REF] Miles | Qualitative data analysis -an expanded sourcebook[END_REF] Are there any barriers to modeling to be identified?

In the following the paper explains the motivation for our inquiry in section 2. Thereafter follows section 3 explaining how the research project was designed and conducted together with a short description on how the collected research material was analyzed. Thereafter follows section 4 where the questions above are attended, by using the questions as subsection headings. In section 5, our findings are discussed. Finally, in section 6 limitations of our work are emphasized and further work suggested. modeling. As part of their study they introduced an a priori process-modelingpractice (PMP) model [START_REF] Iden | Process change projects: a study of Norwegian practice[END_REF] and a revised PMP model [START_REF] Eikebrokk | Exploring Process-Modelling Practice: Towards a Conceptual Model[END_REF]. Their analyses indicate that a combination of technological, social and organizational factors explain the outcome of model-based project change projects.

Motivated by the fact that little is known about enterprise modeling in practice and with an initial aim to test and further explicate the conceptualizations of the PMP model into another setting, our study was initiated to focus on enterprise modeling in ICT-enabled process change. ICT-enabled process change is a term that denotes the use of information and communication technology as an enabler to change the way organizations work, including changes to business processes to make them more efficient and timely and covering the provision of enhanced information to support better decision making [START_REF] Manwani | IT-Enabled Business Change, Successful Management[END_REF]. The dual focus built into the term ICT-enabled process change made us, at the onset of our inquiry, expect that different types of enterprise models would be developed and/or used as part of the combined process change and information technology initiatives under study.

Research method

Case research is beneficial in the study of ‗why' and ‗how' questions because these deal with operational links to be traced over time rather than with frequency or incidence [START_REF] Benbasat | The case research strategy in studies of information systems[END_REF]. With our overall research question stated as: ‗How is EM used and how can it be used to support ICT-enabled process change in Norwegian companies?' it was decided that a multiple case study would serve our purposes. Yin [START_REF] Yin | Case study research: Design and methods, Fourth Edition[END_REF] defines a case study as an empirical inquiry that investigates a contemporary phenomenon in depth and within its real-life context, especially when the boundaries between phenomenon and context are not clearly evident.

According to Miles and Huberman [START_REF] Miles | Qualitative data analysis -an expanded sourcebook[END_REF] highly inductive, loosely designed studies make good sense when experienced researchers have plenty of time and are exploring exotic cultures. On the other hand, Miles and Huberman [START_REF] Miles | Qualitative data analysis -an expanded sourcebook[END_REF] say, pointing to Wolcott [START_REF] Wolcott | Differing styles on on-site research, or, -If it isnt't ethnography, what is it?‖[END_REF], it is not possible to embark upon research without an idea of what one is looking for and it is also foolish not to make that quest explicit.

Looking into an area with little prior empirical research it was decided to develop a research model for enterprise modeling practice, building on categories and subcategories from the related field of process modeling practice incorporating additional aspects found in literature. In addition a pilot study was conducted to provide additional input to the model. By incorporating the PMP model into the research design, we had an additional opportunity to test and further explicate the PMP models conceptualizations into a new setting in accordance with suggestions found in Miles and Huberman [START_REF] Miles | Qualitative data analysis -an expanded sourcebook[END_REF]. The enterprise modeling practice research model is presented in Karlsen [START_REF] Karlsen | A Research Model for Enterprise Modeling in ICT-enabled Process Change[END_REF].

The enterprise modeling research model was built up of three main categories: Enterprise modeling (EM), Context and Outcome, where Context was defined as the setting of the project comprising organizational characteristics, project specific characteristics and project participant characteristics and Outcome was defined as the phenomena that follow or are caused by enterprise modeling, including attainment of purpose and the effect of enterprise modeling on the ICT-enabled process change project solution. The EM category, which is the focus of this paper, addresses both the development of new models and the additional usage of existing models in relation to the ICT-enabled process change project.

EM was further elaborated by the subcategories (1) Management support, (2) Modeling Guidelines, (3) Modeling tools, (4) Individual modeling or workshop, (5) Participation and involvement, (6) Resistance, [START_REF] Karlsen | A Research Model for Enterprise Modeling in ICT-enabled Process Change[END_REF] Modeling languages and (8) Modeling artifacts [START_REF] Karlsen | A Research Model for Enterprise Modeling in ICT-enabled Process Change[END_REF]. The work of Eikebrokk et al. [START_REF] Eikebrokk | Process Modelling Practice: Theory Formulation and Preliminary Results[END_REF][START_REF] Eikebrokk | Exploring Process-Modelling Practice: Towards a Conceptual Model[END_REF], Davenport [START_REF] Davenport | Process innovation: reengineering work through information technology[END_REF], Sedera et al. [START_REF] Sedera | A success modell for business process modeling: findings from a multiple case study[END_REF] and Sommar [START_REF] Sommar | Business process modeling introduction, tutorial[END_REF], were used to motivate both these definitions and the expected outcomes of enterprise modeling.

Having designed a research model to focus and bound the collection of data, in accordance with Miles and Huberman [START_REF] Miles | Qualitative data analysis -an expanded sourcebook[END_REF], we then conducted an exploratory /explanatory multiple case study on combined process change and information technology initiatives.

We used the telephone and internet to search for relevant cases, and ended up with an inquiry of eight Norwegian cases, defined as a constellation of (1) a main organization or (2) a consulting company and/or an IT-vendor. The main organizations of these cases were related to the construction industry (case C1), the marine sector (cases C2 and C4), the maritime sector (cases C3 and C8), the offshore sector (case C5), a wholesaler within the food sector (case C6) and the banking sector (case C7).

To prepare for the case study an interview guide was developed, containing semistructured open-ended questions based on the categories of the enterprise modeling research model that was developed in the initial stages of the project. A total of thirty informants were interviewed as part of our investigation, generating 40 hours of tape recordings: two ‗expert informants', six informants at the pilot stage to underpin the research model and twenty-two informants related to our eight cases. In addition a rich variety of material was collected in the form of model prints, reports and historical material, as recommended by Yin [START_REF] Yin | Case study research: Design and methods, Fourth Edition[END_REF]. Organizational information was additionally downloaded from the internet. We also visited the various companies and got demonstrations of the software solutions involved.

It was decided that a criteria for being included in the study was that the organizations should be -available and willing‖, in the sense of being available and willing to provide in-depth insight into enterprise modeling practice via interviews and supplemental information. The second selection criterion was that the respondents defined their projects as ICT-enabled process change.

We had no initial knowledge of the enterprises and their modeling practice at the onset of the inquiry. With such limitations on what to find we chose to use the term enterprise modeling in a broad sense to capture how the companies in fact used modeling; possibly by using both formalized and non-formalized languages, simple tools etc.

All interviews were transcribed and transferred into Nvivo 9, a computer-assisted qualitative data analysis software package, generating more than 500 pages of transcribed text together with links to all other types of material for analysis. Nvivo 9 provided opportunities to run a variety of built-in queries and helped in keeping track of all material collected by providing database facilities.

The research model that originally guided data collection was also used in the initial computer-assisted analysis by providing initial constructs on characteristics of context possibly influencing on the modeling process, constructs on characteristics of the modeling process and the outcome of modeling.

To guide the analysis we used -Qualitative analysis: An Expanded Sourcebook‖ by Miles and Huberman [START_REF] Miles | Qualitative data analysis -an expanded sourcebook[END_REF]. This book gives a thorough explanation of coding as analysis, where coding is described as tags or labels for assigning units of meaning to the descriptive or inferential information compiled during a study.

The coding process of the interview transcripts started by building a node tree in Nvivo 9 containing the initial constructs of the EMP research model. Then a read through of all interviews was conducted whereby passages of text in the interview transcripts were linked to the appropriate initial nodes. In this process text passages which did not fit the initial nodes were in vivo coded and later specified under new appropriate nodes after a process of revealing appropriate new constructs.

To increase the quality of the coding process the material was re-read to check that nothing important had been missed in the reading process. Missed text sequences were linked to existing or new nodes. Thereafter followed a process where all material linked to each node was controlled to ensure consistency between selected text and the node assigned. Thereafter followed a process where material connected to a particular node was challenged to see if it should be broken into sub-nodes. If a subclassification seemed appropriate the divide was done.

The coding process ended up with an array of different constructs representing the findings done in conjunction with the questions we raised, concerning characteristics of context possibly influencing on the modeling process, characteristics of the modeling process and outcomes of modeling.

Modeling practice

Our initial analysis focused on the case distribution of our eight cases among different constellations of ICT initiatives, process change main focus and modeling objectives. This analysis led to the identification of five different types of enterprise modeling initiatives in our study which we called Strategy, Industry, Dataflow, Work and Support [START_REF] Karlsen | Benefits of different types of enterprise modeling initiatives in ICT-enabled process change[END_REF].

The ‗Strategy' initiative (S) was identified and defined as modeling to reach a change strategy in a long term business change initiative with a mixed focus on improving work practice via physical intervention and improving information flows via IT. With reference to the tables and figures in this paper, case C1, C2 and C3 apply to this type of modeling initiative. The ‗Industry' initiative (I) was identified and defined as modeling to reveal the build-up of market leaders' IT solutions to develop a joint industry specific IT solution and modeling as input to a preliminary report to communicate the necessary alignment between this joint solution and specific actor needs. With reference to the tables and figures in this paper, case C8 applies to this type of modeling initiative. The ‗Dataflow' initiative (D) was identified and defined as modeling to reveal AS-IS and as input to a requirement specification in a change effort to improve information flows. With reference to the tables and figures in this paper, case C4 and C5 apply to this type of modeling initiative. The ‗Work' initiative (W) was identified and defined as utilizing vendor supplied models to reveal differences between a wearable voice-directed warehouse application system and the organization in a change effort to improve work practice by technology. With reference to the tables and figures in this paper, case C6 applies to this type of modeling initiative. The ‗Support' initiative (Q) was identified and defined as modeling to fill a quality system with process descriptions based on a specific guideline, focusing on developing a business support environment where it is foreseen that in the long run shared common models of work practice will improve business processes. With reference to the tables and figures in this paper, case C7 applies to this type of modeling initiative.

Across our cases a broad variety of different benefits of enterprise modeling were identified in ICT-enabled process change [START_REF] Karlsen | Benefits of different types of enterprise modeling initiatives in ICT-enabled process change[END_REF]. We will now take a closer look into the characteristics of the enterprise modeling process of each case and type of enterprise modeling initiative under study, thereby answering the research questions used as subheadings in the following.

How is the modeling process organized?

Analysis identifies different ways of organizing the various modeling activities as shown in Table 1. 1, illustrates that in the Strategy (S), in the Dataflow (D) and Industry (I) modeling initiatives, modeling activities were organized as workshops with oral participation, meaning that the modeling was written down by an external consultant, whilst participants of the main organization provided oral inputs to the modeling process. This was not the case concerning the Work (W) or Support (Q) initiative.

In the Support initiative they chose to use workshops with active participation in the modeling activity, where employees did concrete mapping of business processes. In addition the quality system initiative was supplemented with the possibility for all employees in the bank to provide inputs to model layouts via a digital mailbox-system named -Supply your input‖. The bank also organized a specific user forum where modelers from each business area were represented. The user forum made decisions whether specific process change suggestions collected via the -Supply your input‖ should be universally applied in the banks' preferred process portfolio. If so, the corresponding process model in the quality system got changed. Group based modeling was used in the Work initiative, where a group of representatives from the main organization and external representatives, compared vendor supplied models with what was going on in the warehouse building. Differences were subject to debate and lead to necessary tweaks between system and process layouts.

How is participation and involvement in the modeling process?

Comparing the cases further indicates that even though people are not directly involved in the actual drawing of the models, their participation and involvement are evaluated as satisfactory or very good in all cases.

Which tools, languages and guidelines are used for modeling?

By analyzing our cases we identify a varied use of tools, languages and guidelines as illustrated in Table 2. In the construction case, C1, Microsoft Excel and Word are used as the tools for modeling. In the Marine subcontractor case, C2, no specific modeling tool is used, but comes in a flavor of Excel, PowerPoint and Visio made models. In the Maritime subcontractor case, C3, it is stated that no specific modeling tools are used. A model example from the case shows a -rich picture‖ type of model made in Word. In the Marine laboratory case, C4, Word is identified as the common modeling tool used in the project. In the Off-shore subcontractor case, C5, PowerPoint is the tool chosen.

C6 relates to the Work initiative where modeling is defined as utilizing vendor supplied models when implementing a standardized ICT system. In the Banking case, C7, the quality system application itself is used for modeling. In addition one can state that in general no specific modeling tools are used due to a highly varied practice in the bank across departments and project participants. In the Industry case C8 tool use is said to differ between enterprises adopting the industry specific enterprise resource planning solution.

Concerning guideline use, analysis reveals that this can vary along the time-axis of the project lifecycle and among project participants. In the Support initiative they had a common framework on how to build the quality system for modelers and facilitators. They also used external consultants in each business area to make sure that the modeling standard was followed. In cases C2 within Strategy and C4 and C5 within Dataflow, external consultants used a consultant variant modeling guideline in their work. In case C4 employees reported that before the consultant entered the company no concrete guidelines were used. In C1, process description from a similar enterprise was used as a template to set up a description of the company's own processes. But in general no specific modeling guidelines were used.

Concerning modeling language the majority of cases report that no specific language was used. In cases where modeling language were reported to be used, it turned out that they spoke about some sort of a -consultant variant‖. 3, analysis shows that in all cases process descriptions are made as part of the process change process (except for the Work initiative where models are used). Technological models are developed in three cases: In C2 Use Cases are developed, in C4 database models are developed and in C5 a system draft evolves in parallel with the development of the process descriptions. In C8, marked with a *, technological models of different solutions were used years ago, when developing the joint industry-specific solution. The construction case, C1, is the only case where models from other sources, textbooks and downloaded documents from the Internet, were adapted to be used as part of the process change process. In one example the consultants adapted a model from a textbook to illustrate to employees in the main organization what they meant by a holistic enterprise understanding. 4.5 What might influence the selected way of organizing the modeling process as for example workshops with oral participation or workshops with active participation?

Which artifacts are produced in each type of modeling initiative?

By comparing the respondents' answers on modeling maturity, the main organization's and the externals' modeling capability and experience of modeling, analysis indicates that in most cases the externals' capability of modeling is seen and reported as high, or at least much higher than what is the situation in the main organization. In one case, C6, the capability and experience with modeling is reported as low both in the main organization and among the externals. In C7 modeling capability is reported as generally high in the main organization, but that it of course varies. In C4 and C8 the capability of modeling in the main organization in general are seen as low, but that there are persons that have some modeling experience from previous projects. By combining these findings with the organization of modeling activities in terms of using workshops with oral participation or workshops with active participation etc., the relationships are revealed as shown in Figure 1.

Figure 1. Modeling maturity versus organization of modeling activities

The matrix indicates the following relationships between the ways of organizing the modeling activities related to the modeling maturity of different project participants:

(1) In cases where the modeling maturity of the external representative is reported as high and the modeling maturity level of the main organization as low or medium to low, workshops with oral participation are used to organize the modeling efforts. This way of organizing the modeling activities is in some cases supplemented with individual modeling, whereby the external representative sits down and do modeling by him-self based on interview inputs.

(2) In the case where modeling maturity is reported as high both in the main organization and among the external participant, workshops with active participation are used.

(3) In the case where the modeling maturity level is reported as low both in the main organization and among the external participant, group-based model use is applied. In this instance lack of knowledge on modeling does not stop the participants from finding vendor supplied models useful in the project.

Are there any barriers to modeling to be identified?

In the initial research model ‗Resistance' was one of the sub-categories of the enterprise modeling process. Analysis reveals that there are in fact different types of barriers to modeling which we have grouped into: (1) Challenges, (2) Moderators and (3) Resistance. We identify and define ‗Challenges' as barriers to modeling related to the actual act of model making. ‗Resistance' is identified and defined as negative feelings associated with modeling. ‗Moderators' is identified and defined as barriers to modeling that hinder the actual use of modeling in ICT-enabled process change.

Analysis shows the distribution of challenges, moderators and resistance among our cases and different types of modeling initiatives, as illustrated in Table 4, Table 5 and Table 6. As can be seen from Table 4, Support (Q) is the only initiative where challenges associated with understanding graphical images due to conceptual problems is reported.

Concerning the moderators of modeling, Table 5, analysis indicates that project participant characteristics, project specific issues, IT system issues, information issues and resource issues influence the modeling process. This is done by moderating, restricting or reducing, the modeling process in the different cases.

Project participant characteristics moderating the modeling initiative: Case 6 is the only instance where moderators associated with project participant characteristics are identified. In general, the main organization in this case works close with one specific IT specialist, serving their general needs for IT services. In this case the use of vendor supplied models is reported as a special event, a specific type of modeling initiative, in the everlasting improvement project where the IT service provider and the main organization live in what is called a symbiotic relationship. In general the IT service provider sees itself as well-informed about their customer and therefore sees little need for making models. The IT provider also pinpoints that a more directly focused work approach reduces the use of models in general. On the other hand, the situation of introducing -voice direction‖ was something new for all parties, and the vendor supplied models came in handy when the IT provider worked to adapt the organization to the way the system demanded and vice versa.

Project specific issues moderating the modeling initiative: In C6 the IT-provider do see the usefulness of modeling in some situations but emphasizes that in this case the history of the project is important and explains the reduced need for modeling in their day-to-day improvement work with the main organization. In general, concerning other customers, the IT-provider links reduced use of modeling to instances where customers are unwilling to pay time on modeling, and instances where they as an IT-provider is not -good enough‖ on demanding such spending.

IT-system issues moderating the modeling initiative: IT system issues are related to case 8, the type of modeling initiative where an industry specific solution is developed and implemented. In this case it is stated that the desire to follow the sheep with the bell, the leading organization in the industry, reduces the need for modeling. The reason is that the industry leader has been markedly engaged in developing the industry specific solution, so their processes are somehow embedded in the ITsolution. It is realized that by implementing the industry specific IT-solution one at the same time adopts the embedded business processes of a marked leader.

Information issues moderating the modeling initiative: Two cases report that their modeling initiative is moderated by information issues, C2 and C8. In C2 it is emphasized that all information needs are not covered by process descriptions and in C8, the case from the maritime sector, it is reported that everything cannot be specified, for example -building a boat‖.

Resource specific issues moderating the modeling initiative: As can be seen from Table 5 both the Strategy initiative, the Support initiative and the Industry initiative report on lack of resources as a limiting factor on modeling practice. 6 shows that in four out of eight cases no resistance to modeling is experienced. In three of the cases resistance is experienced but has decreased. The reasons why resistance has changed can be seen directly from the table. The only case reporting on an ongoing negative feeling towards modeling is in B8 case, where it is stated that this is linked to what is their job focus; to build boats.

Discussion

Comparing our findings with the initial research model leads to an enriched picture of enterprise modeling practice. Concerning our question on how the modeling process is organized, our analysis shows that the EMP research model's category -Individual modeling or workshop‖ [START_REF] Karlsen | A Research Model for Enterprise Modeling in ICT-enabled Process Change[END_REF] should be more fine-grained to include the following constructs: Workshop with oral participation, Workshop with active participation, User forum, Supply your input, Group-based model use and Individual modeling.

Based on our analysis in section 4.5 on what might influence the selected way of organizing the modeling activities, as for example workshops with oral participation or workshops with active participation, we propose that the distribution of modeling maturity of project stakeholders influence the way the modeling activities are organized.

Concerning our question on participation and involvement in the modeling process, analysis shows that even though people are not directly involved in the actual drawing of the models, their participation and involvement are evaluated as satisfactory or very good. The key to these perceptions might be understood by the reported outcomes of modeling, where modeling is seen as an awareness-raising process in itself, as a communication tool or a thinking tool among others [START_REF] Karlsen | Benefits of different types of enterprise modeling initiatives in ICT-enabled process change[END_REF].

In [START_REF] Karlsen | Benefits of different types of enterprise modeling initiatives in ICT-enabled process change[END_REF] a broad variety of different benefits of enterprise modeling associated with the five types of modeling initiatives in our empirical investigation are reported. Looking into the artifacts made and the tools, languages and guidelines used for modeling, our inquiry indicates extensive use of the Microsoft Office application as a modeling tool across cases. In general no specific modeling guidelines are used, except for instances where one finds some sort of -consultant variant‖ guideline. Concerning modeling language the majority of cases report that no specific language is used. In cases where modeling language are reported to be used, it turns out that they again speak about some sort of a -consultant variant‖. Concerning which artifacts are produced in each type of modeling initiative our analysis shows that in all cases process descriptions are made as part of the process change process. This finding is not surprising since we have investigated cases which by the interview objects have been understood and defined as ICT-enabled process change.

Comparing the tools, guidelines and languages used for modeling in our study with the modeling benefits produced, we conclude that even the simplest modeling tools and the simplest non-standard model-layouts can provide great value to project participants. The quality system initiative is the only instance where challenges associated with understanding graphical images due to conceptual problems is reported. In addition this is the only instance where it is reported that some see modeling as high raving and theoretical. Modeling to fill a quality system with models to be shared across time and space seem to raise the need for expressing models in a shared syntax [START_REF] Karlsen | Benefits of different types of enterprise modeling initiatives in ICT-enabled process change[END_REF], as opposed to other cases where models are made as part of a communication process which gives them their immediate meaning.

Despite the various benefits associated with modeling, analysis also reveal three types of barriers to modeling: (1) Challenges, (2) Moderators and (3) Resistance. This finding leads to the necessity to adjust the initial research model which only operated with Resistance as a subcategory. An interesting aspect revealed in the study was the saying that:

"If you can tie modeling up against initial resistance, modeling actually helps because we can more easily see what the problems are." [2. Interview, C3]

In this circumstance reduced resistance becomes an outcome or benefit of enterprise modeling.

Concerning our findings it must be emphasized that our qualitative study has aimed at painting a rich picture of enterprise modeling by investigating modeling practice in depth and within its real-life context. In an attempt to deal with well-known difficulties of case studies we have tried to focus and bound the collection of data by building and using an enterprise modeling research practice model and by applying an interview guide in the field in accordance with recommendations found in Yin and Miles & Huberman [START_REF] Miles | Qualitative data analysis -an expanded sourcebook[END_REF]. In general our study still is subject to various threats and limitations familiar to case-study research as described in Yin [START_REF] Yin | Case study research: Design and methods, Fourth Edition[END_REF] and interviewing as discussed in Kvale [START_REF] Kvale | Interviews: an introduction to qualitative research interviewing[END_REF] who states that the interview is neither an objective nor a subjective method. Focusing on gaining in depth insight from a few Norwegian cases has for instance limited our possibility to make large generalizations. Drawing heavily on related domains or what can be seen as specialized fields of enterprise modeling can be problematic due to context differences when designing a study. In addition, having focused especially on the use of enterprise modeling in ICT-enabled process change has led to a predominance of process modeling in the cases under study. This might be seen as problematic in relation to those who use a more restricted version of the enterprise modeling term: taking a more -total systems‖ approach, like Fraser [START_REF] Fraser | Managing Change through Enterprise models[END_REF] discusses. As a next step in further work we suggest that a revision of the initial enterprise modeling practice research model is in demand, based on the findings of our empirical inquiry; some of which has been the subject of this paper. We also see the need for this revised model to be tested out in situations where projects use enterprise modeling from a more holistic approach than what has been practice in our cases. To increase the ability to make large generalizations we also see the need for large surveys. In such studies we hope our findings can provide useful inputs.

Table 4 .

 4 Modeling challenges Case C1 C2 C3 C4 C5 C6 C7 C8 Type of modeling initiative S S S D D W Q I Conceptual problem related to understanding graphical images +

Table 1 .

 1 Individual modeling or workshop etc.

		C1 C2 C3 C4 C5 C6 C7 C8
		S S S D D W Q I
	Workshop with oral participation	+ + + + +	+
	Workshop with active participation		+
	User forum		+
	Supply your input		+
	Group-based model use		+
	Individual modeling	+	+	+
	At the type of modeling initiative level, Table

Table 2 .

 2 Guidelines, Languages and Tools

	Case	C1 C2 C3 C4 C5 C6 C7 C8
	Type of modeling initiative	S S S D D W Q I
	Tools:
	The quality system application			+
	Word	+	+ +
	Visio	+		+
	PowerPoint	+	+
	Excel	+ +
	Guidelines:
	Had guidelines	+ +	+ +	+
	Had no concrete guidelines	+	+ +		+
	Use of vendor supplied models			+
	Languages:
	Modeling language used	+		+
	Modeling language not used	+	+ + + +	+
	No specific modeling tool is used	+ + +	+ + +

Table 3 .

 3 Artifacts

	Case	C1 C2 C3 C4 C5 C6 C7 C8
	Type of modeling initiative	S S S D D W Q I
	Process descriptions	+ + + + +	+ +
	Meta models			+
	Organization charts	+
	Technological models	+	+ +	*
	Adapted models from text books and other sources +
	With reference to Table

Table 5 .

 5 Modeling moderators

	Case	C1 C2 C3 C4 C5 C6 C7 C8
	Type of modeling initiative	S S S D D W Q I
	Project participant characteristics:
	Not being good at modeling reduces model making		+
	Knowledge of customers reduces the need for modeling		+
	Lack of historically good experiences with modeling
	reduces the modeling activity		+
	Some customers are not willing to spend time modeling		+
	Not being good enough to demand spending more time
	on planning reduces the modeling activity		+
	The fact that we are more directly focused reduces
	the use of modeling		+
	Project specific issues:
	The history of the project		+
	IT system issues:
	The desire to follow the sheep with the bell with respect
	to the ICT-solution reduces the need for process
	mapping		+
	The IT system lays down guidelines for the modeling
	process		+
	Information issues:
	Everything cannot be specified (like building a boat)		+
	All information needs are not covered by process
	descriptions	+
	Resource specific issues:
	Available staff:
	Day to day activities are not designed for modeling work	+	+
	Low staffing levels acts as a limiting factor	+ +	+
	Money:
	Our level of ambition	+
	Bad economy acts as a limiting factor	+
	Costs associated with modeling	+	+
	Resource related reviews	+	+
	Time:
	Time acts as a limiting factor	+	+ +

Table 6 .

 6 Resistance

	Case	C1 C2 C3 C4 C5 C6 C7 C8
	Type of modeling initiative	S S S D D W Q I
	Yes, resistance present:
	Some people consider modeling high raving and	+
	theoretical
	Yes, because our job is to build boats	+
	Yes, but the resistance has decreased:
	It was changed when they saw the system in practice	+
	Needed to see the point first	+
	Requires a sales job internally to avoid resistance	+
	The resistance changes from high to low	+
	You need to model a while before people see the point	+
	No resistance:
	Experienced no resistance	+* + + +
	Concerning resistance, Table


Sundar Gopalakrishnan
email: sundar@idi.ntnu.no

Guttorm Sindre
email: guttors@idi.ntnu.no

Diagram Notations for Mobile Work Processes

Keywords: Mobile, multi-channel, information system, process model, diagram notation, visual communication

In mobile and multi-channel information system, the geographical location and context of the user when performing some task may be important for the design of IT applications. Yet, mainstream process models seldom capture the "where" aspect, such as the location for performing some activity. In previous papers we have performed an initial analytical evaluation and two controlled experiments comparing some notation alternatives. For all these notation alternatives the underlying assumption has been that they should be achieved as fairly small adaptations of existing process notations, using UML Activity Diagrams as an example. In this paper we provide a more comprehensive analysis of the problems, using 9 principles for visual notations proposed by Moody, and considering clean-sheet design of a process notation in addition to minor adaptations of existing ones. The paper demonstrates how this would result in quite different notations, each with their pros and cons.

Introduction

Business process modelling languages tend not to capture the location of the activities performed. For instance, BPMN [START_REF] Wohed | On the Suitability of BPMN for Business Process Modelling[END_REF] and UML activity diagrams [START_REF] Dumas | UML Activity Diagrams as a Workflow Specification Language[END_REF] capture what (objects), how (sequence and parallelism of activities and decisions), who (swimlanes), when (time triggers and time events), and to a limited extent why (e.g., how a decomposed activity diagram satisfies a higher level activity). For the latter some extensions with process goals have also been suggested [START_REF] Korherr | Extending the UML 2 Activity Diagram with Business Process Goals and Performance Measures and the Mapping to BPEL[END_REF] -but not the location of the activities performed. For traditional office information systems, where work is performed using desktop computers, it is understandable that physical location has not been given much attention. It is much more important whether a task is performed by the Purchases or Salary department than whether the worker is sitting in office 221 or 325, and even in a distributed IS setting, it might not be so important if one of the offices is in another country either, since anyway the usage context is quite similar, thus implying similar requirements for the desktop application.

However, as emphasized in [START_REF] Walderhaug | Experiences from Model-Driven Development of Homecare Services: UML Pro files and Domain Models , in Model-Based Design of Trustworthy Health Information Systems (MOTHIS)[END_REF], the location and context of activities performed is of much higher importance in mobile and multi-channel information systems. For instance, whether a certain information processing task should be performed in the office before going out on a power line repair job, in the car while driving, in the terrain while walking and searching for the exact site of damage, while climbing in the power mast to fix the damage, while driving back from the site, or after having returned to the office -could have a large impact both on quality, efficiency, and job satisfaction, and would therefore be an important process design decision. In turn, this decision should also have a lot of impact on what ICT tools would have to be developed to support the work process, and what requirements that these tools would have to satisfy. For instance, if the task were to be performed on foot in a dense forest, this would require different equipment and imply other usability challenges than what a desktop application is normally faced with.

It is therefore interesting to consider specialized process notations that do show location and or context of the worker. This can be done either by small adaptations of existing notations like BPMN or UML activity diagrams, or by a more radical "clean sheet" design of a novel notation specifically supporting the modelling of mobile work processes. In some previous papers [START_REF] Gopalakrishnan | Alternative Process Notations for Mobile Information Systems[END_REF][START_REF] Gopalakrishnan | Adapting UML Activity Diagrams for Mobile Work Process Modelling: Experimental Comparison of Two Notation Alternatives[END_REF][START_REF] Gopalakrishnan | Adapted UML Activity Diagrams for Mobile Work Processes: Experimental comparison of colour and pattern fills[END_REF] we have mainly looked at the former alternative, investigating some minor adaptations of UML activity diagrams. The purpose of this paper is to make a more general evaluation of the relative merits of both alternatives, i.e. also opening for proposals of notations that are radically different from the mainstream, using Moody's 9 principles for visual notations [START_REF] Gopalakrishnan | Alternative Process Notations for Mobile Information Systems[END_REF]. The research questions for this paper are as follows:

RQ1: What are the most plausible visual variables to use for showing location in process models? RQ2: What are the relative merits of designing from scratch a novel process notation for mobile information systems versus minor adaptations of existing notations?

The rest of the paper is structured as follows: Section 2 presents background and related work in the area, section 3 presents the notation alternatives. Section 4 provides an evaluation of the notation alternatives, and section 5 concludes the paper.

Background and Related Work

When considering the modelling of location, it is important to differentiate between space and place. The best background for conceptualization of these aspects comes from fields of cartography and CSCW, the latter distinguishing between space and place [START_REF] Dourish | Re-space-ing place: "place" and "space" ten years on[END_REF][START_REF] Harrison | Re-place-ing space: the roles of place and space in collaborative systems[END_REF]. "Space" describes geometrical arrangements that might structure, constrain, and enable certain forms of movement and interaction; "place" denotes the ways in which settings acquire recognizable and persistent social meaning in the course of interaction. In this work we look at modelling of 'place'. Work combing modelling of space (e.g. in maps) and conceptual aspects are described in [START_REF] Nossum | Integrated Quality of Models and Quality of Maps, in Enterprise, Business-Process and Information Systems Modeling[END_REF].

In previous papers we first performed a preliminary analytical evaluation of some notation alternatives in [START_REF] Gopalakrishnan | Alternative Process Notations for Mobile Information Systems[END_REF], the evaluation based on a semiotic framework [START_REF] Krogstie | Using a Semiotic Framework to Evaluate UML for the Development of Models of High Quality, in Unified Modeling Language: Systems Analysis, Design, and Development Issues[END_REF]. Then we compared the most promising notations in experiments [START_REF] Gopalakrishnan | Adapting UML Activity Diagrams for Mobile Work Process Modelling: Experimental Comparison of Two Notation Alternatives[END_REF][START_REF] Gopalakrishnan | Adapted UML Activity Diagrams for Mobile Work Processes: Experimental comparison of colour and pattern fills[END_REF], which revealed that a notation using coloured nodes for capturing location fared better than using patternfills or UML notes. However, there are a lot of other possible notations not evaluated yet, especially radically new notations, as the previously mentioned studies focussed on minor adaptations of UML activity diagrams.

Moody [START_REF] Moody | The "Physics" of Notations: Toward a Scientific Basis for Constructing Visual Notations in Software Engineering[END_REF] defines 9 principles or guidelines for effective visual notations. 1) semiotic clarity means that there should be a 1:1 mapping between graphical symbols and concepts. 2) perceptual discriminability: How easily and accurately can the various graphical symbols be differentiated from each other? It will be easier for the user to distinguish between shapes that are obviously different from a quick glimpse (e.g., squares, circles, triangles) than between shapes that are different only in subtle details (e.g., rectangles with a varying height/width ratio, with or without rounded corners, or with differences in textual font or style inside the rectangle). 3) semantic transparency: How well does a symbol intuitively reflect its meaning? According to Moody, symbols can be either immediate, having a nice intuitive relationship with their corresponding concepts, opaque, having only an abstract relationship, or even worse, they might be perverse, its intuitive interpretation being misleading vs. the represented concept. 4) complexity management: What constructs does the diagram notation have for supporting different levels of abstraction, information filtering, etc.? 5) cognitive integration: Does the notation provide explicit mechanisms to support navigation between different diagrams? 6) visual expressiveness: To what extent does the notation utilize the full range of visual variables available? 7) dual coding: Using text to complement graphics. 8) graphic economy: Avoiding a too large number of different symbols, which would make the notation hard to learn and understand. 9) cognitive fit: Trying to adapt the notation to the audience, i.e. possibly using different dialects with different stakeholder groups. The 9 principles of Moody have already been used in [START_REF] Moody | Evaluating the Visual Syntax of UML: An Analysis of the Cognitive Effectiveness of the UML Family of Diagrams[END_REF] for evaluating the notations of UML, and in [START_REF] Moody | Improving the Effectiveness of Visual Representations in Requirements Engineering: An Evaluation of i* Visual Syntax[END_REF] for evaluating i*. While those papers focused on evaluating existing modelling notations, our focus is to use the 9 principles to guide proposals for new notations.

There have been several efforts presenting adaptations of diagram notations. Mendling et al. [START_REF] Mendling | On the Usage of Labels and Icons in Business Process Models[END_REF] propose to insert small icons inside each business process activity, but not to indicate location, rather the nature of the activity, where the authors identify 25 generic labels. Some examples of concepts represented using such iconic labels are "assess" (using a weight scales icon), "complete" (using a green filled circle with a white check mark), "decide" (using a question mark), "promise" (using a handshake symbol), and "search" (using a magnifying glass symbol) [START_REF] Mendling | On the Usage of Labels and Icons in Business Process Models[END_REF] (p.52).

Most closely related to this paper is work by Baumeister et al. [START_REF] Baumeister | Extending Activity Diagrams to Model Mobile Systems, in Objects, Components, Architectures, Services, and Applications for a Networked World[END_REF], where the authors propose some extensions to UML activity diagrams specifically targeting the modelling of mobile systems. In particular, it distinguishes between what the authors call a responsibility centered notation, where swim-lanes are used to indicate "who" performs and action, and a location centered notation, where swim-lanes indicate "where" an action is performed. In the responsibility centered notation location is instead indicated by the addition of textual labels in action or actor nodes, and similarly, the responsible actor is indicated by textually labelled actor objects in the location centered notation. Since responsibility centered notation is the standard usage of swim-lanes, it is location centered notation which represents the major novelty or deviation from normal practice. This resembles a notation which was briefly tried but dismissed in [START_REF] Gopalakrishnan | Alternative Process Notations for Mobile Information Systems[END_REF] because the need for showing responsibility by other means created a lot of extra nodes and edges in the diagram, thus creating a messy diagram that would be hard to comprehend especially for stakeholders with limited technical skills.

Decker [START_REF] Decker | Modelling Location-Aware Access Control Constraints for Mobile Workflows with UML Activity Diagrams[END_REF] also proposes an adapted notation of UML activity diagrams, specifically targeting access control for mobile workflows. Each activity node can be linked to one or a series of location nodes, shown by parallelograms, to indicate that it is compulsory or prohibited to perform certain activities in certain locations. [START_REF] Decker | Modeling Mobile Workflows with BPMN[END_REF] makes a similar proposal for BPMN diagrams, again showing locations by icons with a parallelogram shape. Thus creating separate nodes for locations, this slightly resembles the usage of UML notes to indicate locations, as investigated analytically in [START_REF] Gopalakrishnan | Alternative Process Notations for Mobile Information Systems[END_REF] and experimentally in [START_REF] Gopalakrishnan | Adapting UML Activity Diagrams for Mobile Work Process Modelling: Experimental Comparison of Two Notation Alternatives[END_REF], however with poorer user performance than an alternative approach of coloured nodes.

Walderhaug et al. [START_REF] Walderhaug | Experiences from Model-Driven Development of Homecare Services: UML Pro files and Domain Models , in Model-Based Design of Trustworthy Health Information Systems (MOTHIS)[END_REF] used UML notations extensively in the MPOWER project with homecare services and conclude that UML profiles can be used as a mechanism for tool chains based on OMG's Model Driven Architecture (MDA) and UML standards. Work on mobile ontologies by Veijalainen [START_REF] Veijalainen | Developing Mobile Ontologies; who, why, where, and how?[END_REF] supports the idea of the 'where' aspect as essential in mobile processes, but excludes the 'what' aspect. Larsson [START_REF] Larsson | Designing for use in a future Context -Five Case Studies in Retrospect[END_REF] proposes the three building blocks for knowing the processes list How, What and Why, adds Who for use oriented design approach but omitted the 'Where' concept.

Notation alternatives

There are a number of notation alternatives that have so far not been explored in our experiments [START_REF] Gopalakrishnan | Adapting UML Activity Diagrams for Mobile Work Process Modelling: Experimental Comparison of Two Notation Alternatives[END_REF][START_REF] Gopalakrishnan | Adapted UML Activity Diagrams for Mobile Work Processes: Experimental comparison of colour and pattern fills[END_REF], nor by the initial analytical evaluation in [START_REF] Gopalakrishnan | Alternative Process Notations for Mobile Information Systems[END_REF]. Bertin [START_REF] Bertin | Semiology of Graphics: Diagrams, Networks[END_REF] presents 8 different visual variables that might convey meaning in diagrams:

• planar variables: horizontal position, vertical position • retinal variables: size, brightness (="value"), texture, colour, orientation, and shape. As Bertin points out these can be used alone or in combination to give different meanings to diagrammatic constructs, and so far we have only explored the usage of some of these variables. Using planar variables to indicate location of activities would mean that an activity node's placement in the diagram would denote the location where the activity takes place in the real world. Instead using retinal variables, variations in the visual appearance of the activity node would indicate the place where the activity is performed. Figure 1 illustrates a spectrum of possibilities. The first row indicates the planar alternative (embedding activity nodes in pools, in a practical example there would of course be several pools and several activities in each pool), the remaining rows showing retinal alternatives, either just adding text (first row), adding an extra location node (next three rows), or providing variations of the activity node itself, e.g., in the bordering line (last four rows), fill (three rows above those), shape, size, or orientation. Many of these alternatives would not provide good notations, but are included just for completeness. The first question is whether we should go for an entirely new notation, or a smaller adaptation of existing notation. There are of course pros and cons to both these alternatives:

• entirely new notation has the advantage that one is free to make optimal choices vs. notation design, specifically fitting the representational challenge at hand. On the other hand, more work is needed to establish the notation and supporting tools, making it less likely that the notation will be adopted by anybody.

• smaller adaptation of existing notation(s) have the advantage of leveraging the investment found in existing tools and analyst knowledge (i.e., more likely to pick up a notation which is a small adaptation of something they already know). On the other hand, there is less freedom in developing the notation since most of the choices made in existing notation must be retained, thus the notation might not be visually optimal. In the following we will discuss these two possibilities separately, considering entirely new notations in section 3.1 and adaptations in section 3.2.

Entirely new notations

For an entirely new notation, the usage of planar variables (horizontal and vertical placement) could be the most intuitive choice to indicate geographical location, as this the normal approach for spatial relationships in maps, which most people have somehow been accustomed to without any IS education. As discussed in [START_REF] Nossum | Integrated Quality of Models and Quality of Maps, in Enterprise, Business-Process and Information Systems Modeling[END_REF], due to the different meta-meta model of maps and conceptual models, there are differences in how to exploit the nine principles of Moody. Cartography revolves, generally, around geographical information which is strongly reflected in the visualization used. Generally the visualization can be said to comprise three graphic primitives; point, line, and area, and relations between these. This is inherently different from metameta models in conceptual modelling which usually comprise only nodes and links between nodes, in addition to containment. From [START_REF] Nossum | Integrated Quality of Models and Quality of Maps, in Enterprise, Business-Process and Information Systems Modeling[END_REF] we have the following guidelines based on the work on MAPQUAL:

1. Clearly discriminate between geographical oriented lines and conceptual lines (relationships) 2. Clearly differentiate between nodes (concept) which are often depicted by a geometric shape, and geographic areas (by texture or colour for instance) 3. Indicate topological information by positioning of conceptual nodes according to the topology where relevant. 4. Position concepts according to their temporal nearness. 5. Use visual variables where appropriate, especially the use of colour and shading for differentiation is necessary for integrated models. 6. Design the visualization based on the participants' cognitive metaphor of the most important information attribute. For instance, temporal attributes tend to be lean towards a sequential metaphor. Spatial attributes, like nearness, tend to lean towards a distance metaphor (i.e. closer is nearer).

The work in [START_REF] Nossum | Visual Representation of Integrated Information[END_REF] illustrates that the new conceptualization might be promising, in particular when combining space and conceptual aspects. Looking on the different archetypical work-places as discussed in the start of section 2 (stationary in office, stationary visiting, travelling by own means, being transported, wandering) one often needs to differentiate between a limited number of places.

The idea of using swim-lanes for location was briefly tried out in [START_REF] Gopalakrishnan | Alternative Process Notations for Mobile Information Systems[END_REF] but dismissed because it created messy diagrams. If using swim-lanes pools for location, the challenge becomes how then to show which role or organizational unit is responsible for various tasks. The attempt in [START_REF] Gopalakrishnan | Alternative Process Notations for Mobile Information Systems[END_REF] was to use the stick-man figure, since this is anyway a well-known symbol in UML. The problem was that links then had to be drawn from every activity to some stick-man figure, and in anything beyond extremely simple process models, crossing links made the diagrams hard to read. However, considering entirely new notation, one does not have to be loyal to UML notation and use the stick man figure, instead the actors for activities can be indicated by means which do not create extra nodes or links in the diagrams, for instance:

• colour or texture. These do not have any obvious intuitive correspondence with various organizational units, thus needing a legend associated to each diagram, although one could imagine developing domain-specific conventions for various organizational units typically involved. • iconic labels inserted in the activity nodes. These have an advantage over colour in being easier to understand intuitively, for instance HR dept = stick figure, sales = dollar, salaries = pay sack, production = gear wheel, R&D = question mark, top management = exclamation mark, etc. A downside versus colour might be if presenting huge models with limited space, when icons inside activity nodes might become small and make the diagrams appear overloaded. Figure 2 and Figure 3 show the same simplified example of a mobile work process in municipal home care, initiated by a shift leader distributing patients on various home care assistants (e.g., depending on patient needs and available assistants, feasible geographical allocation, etc.). Each home care assistant then decides on the visiting sequence of the allocated patients and drives off on the visiting round. On the way to each patient the assistant gets preliminary information about the patient, preferably by audio to allow for sufficient attention to the driving. For each visit, the assistant takes care of the necessary task for the patient and, when returning to the parked car, immediately logs the visit, possibly also registering special needs that must be taken care of on the next visit (e.g., buying new light bulbs). In case the patient's health condition does not appear to be normal, the assistant may contact a nurse who will take further action if necessary.

In Figure 2 swim-lanes are used for denoting the different locations where this work-process is played out, while white and grey-tones for the activity nodes show the actors. Colour would be even more illustrative, but grey-tones were used here for the purpose of b/w printing. In Figure 3 bounding boxes similar to swim-lanes are again used for location, but this time the different locations are even more emphasized by using different background colour inside the bounding boxes, plus some illustrative icons (office building, driving car, parked car, homes, and red cross for the clinic) to indicate the nature of the various locations. Instead of using different grey-tones inside the activity nodes, icons are used also here, to distinguish between activities performed by the shift leader, the home care assistant, and the nurse.

Adapted notations

Existing process modelling approaches like BPMN or UML Activity Diagrams tend to use the planar variables for activity order and possibly organizational placement in swim-lanes or pools. If the goal is to adapt an existing notation, it would make sense to keep using the planar variables for these purposes, so that location would instead have to be shown by retinal variables, cf. Figure 1. Many of these can be dismissed quite quickly using one or more of Moody's 9 principles. For instance, the four lower rows which use variations on the bordering line of the activity node will all be very subtle, with poor perceptual discriminability. Using size will be confusing, as this will intuitively be understood to indicate complexity or importance, not location, giving poor semantic transparency. The same would apply to orientation, intuitively indicating increase or decrease. Using totally different symbols ("shape, big variation") would be a radical change from standard notation and the user would probably be confused that such quite different symbols would all represent activities. On the other hand, the alternative "shape, small variation" suffers from poor perceptual discriminability, and worse the more locations must be distinguished. The alternatives with separate nodes have problems with regards to the principle of complexity management, since they cause a substantial increase in the number of nodes in the diagram, and thus also to the number of links between nodes, easily causing crossing lines and reduced readability. This was probably a key reason why a notation using colour performed significantly better than a baseline notation using UML notes in an experiment [START_REF] Gopalakrishnan | Adapting UML Activity Diagrams for Mobile Work Process Modelling: Experimental Comparison of Two Notation Alternatives[END_REF]. The advantage of using UML notes, on the other hand, is that it does not require any changes to standard UML notation.

In another experiment [START_REF] Gopalakrishnan | Adapted UML Activity Diagrams for Mobile Work Processes: Experimental comparison of colour and pattern fills[END_REF] the alternatives with colour-fills and pattern-fills performed equally well, although opinion-wise the experiment subjects had a strong preference for the colour version. Another possibility that might be tempting to try out is the "icon in icon" alternative. This shares the advantage of colour-and pattern-fills that the number of nodes and links in the diagram is not increased. If one is able to make intuitive icons, it would have an additional advantage in terms of higher semantic transparency. On the other hand, it would have a potential disadvantage for the principle of graphical economy (adding more different symbols to the notation), and in a large model with many small activity nodes, icons may become smallish and hard to read.

In Figure 4 the same home care example as in Figures 2 and3 is shown again, now using planar variables for responsibility (swim-lanes) and activity order (top to bottom), and instead showing location by pattern fills. Colour got even better results than pattern-fills in the experimental evaluation, but pattern-fills are used as an example here for the purpose of black/white printing. Anyway, whether using patterns, colour or grey-tones, the diagrams would be structurally the same.

Figure 5 then shows the same example instead using icons to indicate the locations of actions. Four different icons are used, an office building for tasks performed in the office, a car with an arrow on top for tasks performed while driving, the same car with a P-sign above for tasks performed while parked, and a house for the patient's home. A legend might be useful for these also, but the much more intuitive relationship between these symbols and what they stand for, means that the user would likely learn and remember them more easily.

Evaluation of notations

Not all of Moody's 9 principles [START_REF] Moody | The "Physics" of Notations: Toward a Scientific Basis for Constructing Visual Notations in Software Engineering[END_REF] are equally relevant to us. Two of the principles are excluded, namely cognitive integration, because it concerns relationships between several diagrams or diagram types while we are only considering activity diagrams at this point, dual coding, because this concerns the combination of text and visual means -which can be done fairly independent of what visual trick we use for location, and cognitive fit, which concerns the usage of different dialects for different stakeholder groups (where, if anything, we would need representatives from these various groups to perform the evaluations rather than doing it ourselves). This leaves us with 6 of Moody's principles, on the other hand we add one additional criterion which is not in Moody's list, namely support for multiple locations. In our examples in Figure 1, each activity is shows as taking place in one particular location. However, for a mobile information system some activities must be supported in many different locations, so that it is up to the user's preference where to perform it (e.g., either in the office or in the car). Some activities might even take place in several places at once, for instance if performed by two collaborating persons in different locations. The need to attach several locations to some activities might obviously cause additional challenges to our notation alternatives.

+ + + + + -- +4
The rows in Table 1 are various notation alternatives for location, for space reasons we omitted some that were obviously poor already in the discussion of Figure 1. The columns are the criteria used (SC = semiotic clarity, PD = perceptual discriminability, ST = semantic transparency, CM = complexity management, VE = visual expressiveness, GE = graphical economy, and ML = multiple locations. The scores range from --(very poor), through poor, neutral, good, to very good (++). The tows above the grey line are for notation with small adaptation, i.e., planar variables used for responsibility so location must use retinal variables. Below the grey lines are alternatives using planar variables for location, so that responsibility must be shown by retinal variables. Here we only included the 5 best alternatives from the upper half, since the relative merits of the various alternatives will be pretty much the same whether the retinal variables are supposed to depict location or responsibility. For space reasons we cannot explain all the 105 marks in this table in detail, more information can be found in a technical report [START_REF] Gopalakrishnan | Analytical Evaluation of Notational Adaptations to Capture Location of Activities in Process Models[END_REF]. The analytical evaluation was performed by both authors independently, then going through a consensus process afterwards, to reduce the threat of scoring error and arbitrary interpretation of evaluation criteria. However, both evaluators -although having different cultural backgrounds -came from the same university, and having a four year scientific relationship (supervisor and phd student), so the results must be taken with caution.

The alternatives using fills (either colour, grey-tones or patterns) generally scored well in the evaluations, because they do not introduce new nodes or links (i.e., good for complexity management), put to use visual variables that are not used for any other purposes in the notation in question (i.e., good for visual expressiveness), and are fairly easy to discriminate visually (i.e., good for perceptual discriminability). This is especially true for colour (except for color-blind users), but brightness and texture will also be fine as long as each diagram has a limit of 4-5 different actors or locations that must be distinguished. Another good alternative is the use of meaningful icons inside the activity nodes ("icon in icon"). These have a big advantage where colour-fills and similar alternatives were not impressive, namely in being intuitively understandable, i.e. good for semantic transparency.

As for the choice between the radical, location centered notations using planar variables for location (lower part of Table 1), or the less radical responsibility centered notations using retinal variables for location (upper part), the planar alternatives might be slightly better for semantic transparency, but have problems with multiple locations, in which case activity nodes might have to be duplicated in several swim-lanes. For multiple locations, the dedicated location shape or iconic note will be the best, since an activity node can trivially be connected to a number of location nodes. Icon in icon or colour fills are not too bad either, since one can put several icons or colours inside the same node.

Discussion and Conclusion

Our first research question was about the most plausible visual variables to use for showing location in process models, and the analysis has indicated a two-level choice:

• showing location by planar variables, in which case responsibility must instead be shown by other means; the best seem to be fills in the activity nodes (e.g., colour, grey-tones, patterns) or meaningful icons in the activity nodes. • Showing responsibility by planar variables, in which case location must instead be shown by retinal variables, the most interesting again seeming to be fills or meaningful icons. The second research question was about the relative merits of radical locationcentered notations versus smaller adaptations of mainstream responsibility-centered notations. The choice between these depends on several factors. If similarity to mainstream notations is important, it will be a good idea to keep showing responsibility by planar variables. On the other hand, for semantic transparency, it might be better to use planar variables for location. There is, however, a potential problem with models where some activities can be performed in multiple locations, since it would cause clumsy diagrams if activity nodes must be duplicated in several location pools. For activities supposed to be performable everywhere, there could be a workaround by designating a special "anywhere" pool, but this would not solve the problem for activities that should be supported in a couple of different places, but not all. Hence, while the usage of planar variables for location looks nice as long as the models only need to depict each activity as performed in one place, it might in the more general case not be as interesting as initially believed. From the evaluation tables, the aspect not shown by planar variables (whether this be location or organizational responsibility) can feasibly be indicated for instance by colours or similar fills inside the activity nodes, or by meaningful icons inside the activity nodes ("icon in icon") --or, if multiple locations for each activity is a major issue, possibly putting the iconic nodes as separate nodes in their own right ("iconic node"). A major point made by Moody as reflected in the principle of cognitive fit [START_REF] Moody | The "Physics" of Notations: Toward a Scientific Basis for Constructing Visual Notations in Software Engineering[END_REF], however, is that one should not have to make a choice of only one notation here. A reasonably sophisticated modelling tool should easily allow to switch between different visualizations of the same underlying conceptual model -depending on the preference of the user. So, a quick menu choice could determine whether to hide or show locations in a diagram, using a location-centered or responsibility-centered notation, whether to use colour or pattern-fills or icons -or other visual variables.

A major shortcoming of this work so far is that most of the example notations are only evaluated analytically, which does not allow for as certain conclusions as would be possible with empirical data. We have done experiments comparing the responsibility-centered "text in note", "color-fill", and "pattern-fill" notations, showing that color-fill performed better than notes and was more preferable to users than pattern-fills. However, the "icon in icon" alternative has not yet been tried in experiments, as have none of the location-centered alternatives. An obvious step for further work would therefore be to run more experiments, and also using more varied participant groups than have been used so far (CS students). Another interesting continuation would be case-studies with larger industrial examples. Furthermore, it is not evident that swim-lanes or pools must be used at all. It could also be possible to experiment with notations where planar variables only indicate activity sequencing (e.g., top to bottom) or parallelism (e.g., left-right), showing both location, responsibility and other properties (e.g. time) with combinations of fills, icons, and text. After all, while swim-lanes or pools are visually appealing and have some evident advantages -for instance making it quick for each stakeholder to see what activities he is responsible for if swim-lanes are used for responsibility -they might also increase diagram complexity in many cases. For instance, activities which are subsequent and which would therefore intuitively be close in the diagram, might have to be drawn far apart because they belong to different swim-lanes -which creates longer links and potentially also more crossing links. Again, in a good modelling tool it should be possible to switch quickly between a display using swimlanes or pools to one avoiding it -as well as to enhance or suppress any particular aspect of the model, e.g., being able to select whether the model is to show location of the activities or not. The study of tool support for the various diagram styles discussed in this paper must therefore also be a topic for further work.

Figure 1 :

 1 Figure 1: Showing location by planar (top row) and retinal variables (remaining rows). Fill-colors yellow, blue, white, line colors red, blue, green (if b/w printing)

Figure 2 :

 2 Figure 2: Distinguishing actors by brightness (grey-tones), swim-lanes for location

Figure 3 :

 3 Figure 3: Distinguishing actors by people icons, pools for location

Figure 4 :

 4 Figure 4: Home Care Example, using pattern-fills for location

Figure 5 :

 5 Figure 5: Showing locations of actions by place icons inside activity nodes

Table 1 :

 1 Evaluation of notations, responsibility-centered alternatives above grey line, location-centered alternatives below

	Show location by...	SC	PD	ST	CM	VE	GE ML	Sum
	Text in activity node	-	-			--	++		-2
	Text in note	-	-		--	--	++	+	-3
	Dedicated location shape				--	--	-	++	-3
	Iconic note	+	++	++	-	-	--	++	+3
	Icon in icon	+	++	++	+	-	--		+3
	Shape, small variation	+	-		+	--		-	-2
	Shape, big variation	+	+		+	--	--	--	-3
	Fill colour	+	++	-	+	+	+		+5
	Fill brightness	+	+	-	+	+	+	-	+3
	Fill texture	+	+		+	+	+	-	+4
	Planar, resposibility by
	Iconic note	+	++	++	-	-	--	--	-1
	Icon in icon	+	++	++	+	-	--	--	+1
	Fill colour	+	++		+	+	+	--	+4
	Fill brightness	+	+		+	+	+	--	+3
	Fill texture	+