Design and Verification of Information Systems (DVIS), lectures 1-2

1. Design and Verification of Information Systems (DVIS), lectures 1-2 elementary concepts of workflows workflow = business process BPR - Business Process Redesign (Reengineering) functions of WMS (Workflow Management Systems) three dimensions of workflows subdivision of processes organizational structures mapping workflow concepts onto Petri nets architectures of inter-organizational workflows

2. Introduction to Workflows and WFMS • Management of business processes from the perspective of computing (IT) • WFMS - software packages for managing business processes • old golden rules - first organize then computerize (processes were developed with silent assumption that the business process is managed by people; organizational structure would be developed under which people were allocated tasks; can IS support the work ? • new rules - design business process in a more abstract way without considering implementation; design IS and the organization hand in hand

3. What the course contains ? • reference framework for defining business processes • discussion of analytical methods • Petri nets are extensively used to define and analyze complex processes - PNs can facilitate processes by non-experts (communication between designers and users + existence of software tools) • workflow management systems, i.e. the right information reaches the right person at the right time (generic software packages that can be used in many applications) • methodology for developing workflow applications • case studies of workflow systems

4. What the course contains, ctnd ? • organization of workflows • management of resources that contribute to business processes • static and dynamic techniques to analyze workflows • analysis and properties of inter-organizational workflows • workflows and electronic commerce • examples of WFMS/tools - Renew, Woflan, CPNTools • WfMC - Workflow Management Coalition - to develop standard terminology and standard interfaces for WFMS

5. Classification of Information Systems • IS are used to reduce people’s workload, esp. in offices (text writing - word processors, drawing - drawing systems, calculating - spreadsheet systems, filing - database systems, communicating information - electronic email systems) • Office Information Systems • Database Management Systems • Transaction Processing Systems • Knowledge Management Systems • Decision Support Systems • Control Systems • Workflow Management Systems

6. Organizing Workflows • role of work in society: we work to live, we can not do everything in our life, we are organized in specialized ‘business units’ • change from supply-driven economy to demand-driven economy (customers are scarce) • shift of focus from the means of production to the customer (organizational paradigm shift) • reference framework = ontology of processes = a system of defined terms that describe particular field of knowledge • objectives: to define business-management context within which WFMS operate; to model and analyze processes; to describe the functionality and architecture of WFMS

7. Why Business Process Redesign ? • IT has a role to play in a way how business processes are organized • why this is good ? - because every algorithm defines a process • processes can be defined and analyzed clearly • definition of a process is important to decide whether to implement a process • will the process work properly ? • analyze the process • use formal methods to identify properties or lack of them • simulation techniques, computer animation

8. Organizational Paradigm Shift • from ‘capacity utilization’ - i.e. the more you produce the better • to ‘customer care’ - i.e. the more (satisfied) customer you have the better • WFMS should: • make ‘work controllable’, • to encourage communication between employees, • to build a bridge between ‘people’s work’ and ‘computer applications’

9. Fundamental Concepts of Workflows • task - logical, indivisible, unit of work • case - examples: insurance claim, mortgage application; case always has a particular state • process - how to carry out a particular category of cases • atomicity - tasks of work may be assumed to be atomic • granularity of tasks - discretization of work • economy of scale - one process serves many cases • state - composed of three elements: • the values of relevant case attributes that change as the case progresses being processed • the conditions that have been fulfilled • the content of the case

10. Fundamental Concepts of Workflows, ctnd. • routing - i.e. routing the case; the life cycle of a case is laid down in the process • work item = case + task; actual piece of work; certain workitems can only be transformed into an activity once they have been triggered • activity = case + task + resource; i.e. actual performance of a piece of work • enactment of a case - triggers are required: • a resource initiative (employee taking a work item from a tray) • an external event (arrival of a message) • a time signal (the generation of a list of orders at 6 pm]

11. Subdivision of processes • primary - to produce products or services (production processes); they deal with cases for a customer; customer-oriented even when a customer is not known • secondary - support primary processes (support processes) - maintaining the means of production, personnel management • tertiary - managerial processes that direct and coordinate primary and secondary processes, maintenance of contacts with financiers and stakeholders

12. Three dimensions of Workflow • case dimension - workflow systems deal with cases; cases have case types (such as insurance claim, mortgage application, tax return, patient in a hospital) • control flow dimension - partial order of tasks within a specific case, i.e. how to systematically deal with a case • resource dimension - human and technical resources needed to process a case

13. Organizational Structures • the hierarchical organization - typically functional or capacity groups • the matrix organization - used by building contractors, installation firms, software houses, typically within one single company • the network organization - similar to matrix organization except that typically composed of actors not working in the same organization

14. How to allocate staff into departments? • the capacity group - people with the same skills, they are interchangeable; head of the department keeps its members ‘up-to-date’ (through training); example - typists, maintenance, engineers • the functional department - performs interdependent group of tasks, each often requiring the same skills; head responsible for the work of the department (accounting, marketing) • process or production departments - department is responsible for a complete business process

15. Three Good Reasons for Using Petri net-based WFMS • Reason 1: Formal Semantics despite the Graphical Nature; Petri nets can be used to model primitives defined by WfMC • Reason 2: State-based instead of Event-based (today’s WFMS are event based, i.e. tasks/transitions are modeled and states between tasks are suppressed • Reason 3: Abundance of Analysis Techniques and related Software Tools

16. Reasons for Using State-based Description for WFMS • Reason 1: It allows for a clear distinction between the enabling of a task and the execution of a task (issue of task triggering: automatic, user, message, time) • Reason 2: Possibility of competitive tasks; two tasks are competitive if both are enabled and only one of them may be executed (event-based system can not model this situation) • Reason 3: Sometimes it is necessary to withdraw a case; in PNs this means removal of tokens and triggers that correspond to the cancelled case • Reason 4:Moving a case from one location to another (IOWF) is easy - transfer of tokens and triggers

17. Mapping Workflow Concepts onto Petri nets • process - is specified as a specific Petri net • conditions - are represented as places of Petri nets • tasks - are represented as transitions of Petri net • routing - a specific path of case processing through Petri net describing the process • case - represented as a token or set of tokens located in various places of Petri nets • atomicity of tasks - atomic tasks represented as transitions can be refined into more detailed Petri net; process or part of a process can be abstracted into a single transition or single place

18. Common Errors in Process Definition • tasks without input and output conditions • dead tasks - tasks that can never be carried out • deadlock - jamming a case before reaching condition called ‘end’ • livelock - trapping a case in an endless cycle • dangling tasks - i.e. activities still take place after the case has been completed

19. Fundamental Issues in Workflows • Basic Definitions of Workflows and WFMS • Workflow Patterns • Workflow vs. Inheritance • Dealing with Change in Workflows • Software Architectures and Workflows • Verification of Workflows & Woflan • Inter-organizational Workflows and E-commerce • Reference Nets & Renew

20. Six Basic Software Architectures of Inter-organizational Workflows • Capacity Sharing Architecture (CSA) • Chained Execution Architecture (CEA) • Subcontracting Architecture (SCA) • Case Transfer Architecture (CTA) • Extended Case Transfer Architecture (ECTA) • Loosely Coupled Architecture (LCA)