Workﬂow Automation: Applications, Technology and Research

LSDIS

http://www.cs.uga.edu/LSDIS/ Workflow Automation:
Applications, Technology and Research

Prof. Amit Sheth
Large Scale Distributed Information Systems Lab
Dept. of Comp. Science, The Univ. of Georgia
415 Graduate Studies Research Center
Athens GA 30602-7404 USA

Tel. +1 706-542-2310, Fax: -2966
Email: amit@cs.uga.edu

Tutorial notes, SIGMOD Conference, May 1995, California.

c 1995, Amit P. Sheth.

Collaborations/Acknowledgments: Bellcore (N. Krishnakumar,.. ),
U. of Houston (M. Rusinkiewicz, ..), GTE (D. Georgakopoulos)
MCC (M. Singh,..), ETH-Zurich, LSDIS/UGA (J. Miller, K. Kochut), Clients: Ameritech, CHREF

Future revisions of this presentation can be found at: http://www.cs.uga.edu/LSDIS/

Multidatabase Interoperation SIGMOD95

LSDIS

Preliminaries
This talk will emphasize Workflow Management for Mission Critical
and Enterprise-wide Applications involving heterogeneous informa-
tion systems....
We will only look at some of the issues under the “Workflow
Umbrella” [Georgakopoulos, Hornick, Sheth 95].

Workflow
Business Process Workflow specification
Business Process Workflow implementation
specification/map
Business Process Workflow automation
re-engineering
Workflow management
Business Processes
automation Workflow management system

Note: Trademarks are those of respective owners. ActionWorkflow: Action Tecnologies; Encina: Transarc Corp., FloMark: IBM; InCon-
cert: X Soft; Lotes Notes: Lotus Corp.; ProcessIT: Digital Equipment Corp., SAP Business SQL Server: Microsoft; Workflow: SAP AG;
WorkFlo: Filenet. Any missing reference to trademark is unintentional.

C 1995, Amit P. Sheth 1


LSDIS

Overview

• What’s workflow?
Origin, Advantages, and Example Applications
• Review of Commercial State-of-the-Art,
Markets and Related Technologies
• Basic concepts and specification of workflows
• Components of a Workflow Management System
• Research: past and in progress
• Trends



LSDIS

Origins of Workﬂow
Ten years ago, a team of engineers conceived the idea that computer
software could be used to automate paper-driven business processes.
They called it “workflow software.” [Smith 93]

imaging
document ﬂow
enhanced emails
workgroup support
multi-system apps.



LSDIS

Definition of Workflow (Management)
(some samples)
“Workflow refers to a new set of software and tools for automating
and improving business processes.” [Dyson 1992]
“Workflow is a process by which individual tasks come together to
complete a “transaction” -- a clearly defined business process --
within an enterprise.” [Silver in [2]]
“Workflow is the sequence of actions or steps used in business
process. Automated workflow applies technology to process, though
not necessary to every action.” [Marshak in [2]]
“Workflows are computerized models of business processes...”
[Hollingsworth 94]
“Workflow management is an important tool for structuring and
optimizing business processing... and for supporting the practical
implementation of business process re-engineering.” [Fritz 95]



LSDIS

The lure of workflow:
it fits the trend

Workflow fits nicely with other trends such as
re-engineering, downsizing,
network computing, groupware, and
client-server computing.



LSDIS

The lure of workflow: a large potential market
Market/Revenue Forecast for
Workflow Software($-mil)
Workflow- Production “Transactional
Year
All Workflow Workflow”
1992 226 (ID) 115 (DL)
186 (DL)
1993 628 (ID) 250 44
1994 1200 (ID) 540 106
1995 1800 (ID) 810 184
1996 2500 (IDC) 1120 (DL) 293
2500 (DL)

Sources: ID = IDC & Advante; DL = Delphi Consulting; IT = International Data Corp.

Forecast data used above is old (1993), but it shows an important
reason for vendors’ interest in this market.



LSDIS
Trade Press Characterization of Workflows
Multi-system
Applications &
Transactional
Workflows
Complex
Production Insurance Claims
Task Complexity

Loan Applications
Ad Hoc Product Documentation
Sales Proposals
Administrative Press Releases
Expenses
Travel Requests, Purchase Requests
Simple Messages
Simple Complex
Task Structure

Source: IDC/Avante Technologies, Inc.

Administrative workflows involve repetitive, predictable processes with simple task coordination rules,
such as routing an expense report or travel request through an authorization process.
Ad-hoc workflows involve human coordination, collaboration, co-decision, and often appear in office pro-
cesses such as product documentation or sales proposal.
Production workflows involve repetitive and predictable business processes, such as loan applications
or insurance claims. Unlike administrative workflow, production workflow encompasses an information process
involving access to one or more distributed/heterogeneous/autonomous information systems.

C 1995, Amit P. Sheth [McCready 92, Georgakopoulos, Hornick and Sheth 94] 7


LSDIS

Trade Press Characterization of Workflows (contd..)

Process
Automation

Organizational
Productivity
Benefits
Document
Flow
Task
Automation
Ad-hoc
Workgroup
Tools

Application Integration Complexity

Source: BSG Corp. (see [Als94])

Yet another classification:
Mail-centric, document-centric and process-centric (see [Fry94]).



LSDIS

Workflow (WF) Automation Software:
Example Products
WorkFlo (Filenet)
InConcert (XSoft)
WorkMan (Reach)
FloWare (Plexis)
AWS (Action Tech)
WorkManager (HP)
LinkWorks, ProcessIT, ObjectFlow (DEC)
SAP Business Workflow (SAP AG)
FloMark (IBM Vienna)

About 200 products claim to support workflow features
and/or workflow management!

See [2] and [Georgakopoulos, Hornick, Sheth 95] for a list of vendors and products.

C 1995, Amit P. Sheth Trademarks are those of respective owners. 9


LSDIS

Overview of Current Commercial State-of-the-Art
• Emphasis on office processes:
– imaging
– document flow
– enhanced mail
• Reasonable support for administrative and ad-hoc
workflows
• Many products are little more than fancy diagramming tools
(Dataflow, Digraph, Flowchart, Network, Orgchart,
Pertchart,...), with layout support, capture/import/export of
data from/to databases, spreadsheets, simulation tools
• Some are specialized electronic data management
systems: e-mail, imaging, databases, electronic forms, text,
engineering drawing,..
• Alliances between image/document management, GUI
builder and tools companies (e.g., simulation) are common



LSDIS

Maturing Infrastructure: A Driving Force

Communication Infrastructure used
by Commercial Workflow
Management Systems

e-mail Early 90s - already mature
Work-group (Notes) 1993 - almost mature

Distributed Object Management 1995 - very active
Current Generation Transaction 1996?
Processing Monitors
Agents 1997?



LSDIS

Workflow Management System for
Office Automation vs Enterprise Automation
(Typical Case)
Current workflow/workgroup software supports office
automation functions (involving user tasks) (most products are
in PC and mainframe env.). There is little support for application
automation (involving both user and application tasks with
varied level of transactional properties).

User Task User Task User Task Appl. Task User Task Appl. Task

workflows supported by workflows supported by
most current WMSs some new/emerging WMSs



LSDIS

More Demanding Workflows
some examples--
• Business loan processing in Banks requires coordinating
user tasks such as loan application entry and risk exception,
and application tasks such as risk evaluation, risk update, and
loan decision recording.
• Patient health care support in a health care group
practice requires coordinating user tasks such as patient
registration, doctor’s record review/update, lab work, and
application tasks such as automated billing and statistics
compilation.
• Service provisioning in Telcos require the coordinated
execution of heterogeneous tasks on heterogeneous systems:
• Product life-cycle management.

Support for most mission-critical multi-system enterprise applica-
tions is lacking (Finance, Healthcare, Manufacturing,...)


LSDIS

An Example Application in Business Data
Processing (Loan Processing)

Client credit
worthiness

Enter loan Risk Record
request exception decision

Risk Risk Risk update
evaluation update compensation

Workflow may involve both user and application tasks, as
well as different types of application tasks. Some tasks can
be compensated.

C 1995, Amit P. Sheth
[Breitbart, et al. 93: ETH] 14


LSDIS

An Application (segment)
in a Healthcare Environment
internet
Insurance
Reference Info. company
Billing
Patient Provider
registration encounter

Labwork
Request

Lab
Specialist
review

Workflow may involve multiple organizations, data of different
types/media, different notions of transactions (Domain specific
[e.g., HL7 in Healthcare], EDI, DB), may take several days...


LSDIS

An Application in Telecommunication:
Provisioning a Telephone Service

Customer

Loop

Inter-Office/Trunk Inter-Office/Trunk
Central Office
Central Office

L-D Carrier L-D Carrier



LSDIS Provisioning a Telephone Service (contd..)
Outside
Plant
Engineer

2

Customer
1 Planning Design
Customer
Representative
Work-Force
Adm.
Service
Order
Processor

3a 3b
Billing Controller
Operations
5a 5b Support
7

4a 6 4b
Manual error resolutions 8
Loop Intra-Off. Trunk
Assignment Assignment Assignment

Use of legacy application/information systems is unavoidable.
Migration to new systems and modern distributed computing
environment continue.
C 1995, Amit P. Sheth [Ansari et al 92,Aslo see: Georgakopoulos et al 93] 17


LSDIS

Business Challenges

• Improve flexibility for re-engineering
• Increase automation to reduce cost and improve response time
• Support evolution and migration (accommodate both existing
systems and new systems; increase use of the latter)

Example (Case Study of a Service Automation):
• 40 persons -> 12 persons (work center
reorganization, re-engineering) -> 2-3 person
(automation)
• Six Weeks -> Next Day -> Few Minutes



LSDIS

Some of the key new requirements
• Automation involving heterogeneous software tasks/processes
and user tasks.
• Integration with legacy systems and heterogeneous information
systems; support with-in enterprise and across enterprises
(local, wide area, and wireless). Performance and scalability.
• Use of transaction concepts and technology, reliability, failure
handling/recovery.
• Support for domain-specific tasks (e.g., HL7 in Healthcare),
objects (e.g., EDI) and repositories.
Task and info. sys. heterogeneity

Object/ Data complexity

Coordination/
Correctness



LSDIS

Key Promising Technologies
(and Challenges)

Distributed Object Management
Legacy System Interoperability
Customized Transaction Management



LSDIS

Another Characterization
(that is sensitive to new requirements)

Human-oriented System-oriented
Transactional workﬂows
CSCW

Commercial WFM Systems Commercial TP Systems

[Georgakopoulos, Hornick and Sheth 94]


LSDIS

On Transactional Workflows
Transactional workflows are activities that involve coordinated
execution of multiple related tasks on distributed/heteroge-
neous/autonomous information systems and support
(provide) selective use of transaction properties at individual
task and (intra- and inter-) workflow levels.

In particular, they use transaction management concepts and
technology for specifying and ensuring workflow correctness
and reliability in distributed/heterogeneous/autonomous infor-
mation system environments.

More on this later...

[Georgakopoulos, Hornick and Sheth 94; Early use: Sheth and Rusinkiewicz 93. Also see Mohan et al 95]


LSDIS

(Distributed) Transaction Processing (DTP) vs.
Advanced WFS
(Typical Case)
DTP/D-OLTP is focused on efficient execution of relatively
simple tasks with no coordination across heterogeneous tasks
(in different task groups). Advanced (transactional) workflows
require coordinated execution of heterogeneous tasks, with
varied levels of transactional properties, on a variety of systems.

Task Groups
Task2
Task1 Task4
Task3
Task

Workflow Group
In DTP In TWF
• Earlier queued message systems and “chaining of transactions”.
Problems: insufficient control over transaction properties, one type of task,
interactions among concurrent activities difficult.

[STDL, Encina,...] 23


LSDIS

Related Work:
Database Literature
• ACID transactions and their nested derivatives
Problems: inflexible, difficult to implement in multi-systems.
• Extended/Relaxed Transaction Models:
Sagas and Nested Sagas [Garcia-Molina et al. 88, 90], ConTracts [Reuter
89]. Flexible Transactions [Elmagarmid et al 90, Rusinkiewicz et al 90],
Multi-transaction Activities [Garcia-Molina et al. 90], Open
Nested Transactions [Weikum & Schek 92] and Others (e.g., in [Elmagarmid
92]), ACTA framework [Chrysanthis & Ramamritham 91/92]

• “Workflow” and hybrid models:
Long-Running Activities [Dayal et al. 91], DOM model/TSME
[Buchmann et al 92, Georgokopoulos et al. 93], Third Generation TP Monitors [Dayal
et al. 93], ASSET [Biliris et al. 94]

[Rusinkiewicz and Sheth 94, Mohan tutorial; ETM vs Workﬂow Model-- see Breitbart et al 94]


LSDIS

Workﬂow Management

WFM involves:
• defining workflows, i.e., describing those aspects of
processes that are relevant to controlling and
coordinating the execution of its tasks (and possibly the
skills of individuals or information systems required to
perform each task), and

• providing for automation and re-engineering (fast
(re)design and (re)implementation) of the processes as
business needs and information systems change.



LSDIS

Workflow Management Issues

Workflow Workflow workflow
Process Specification Implementation =
application

• Business Process Modeling/Reengineering
(BPM/R)
• Workflow model & specification language
• Executable application code
• Run time support



LSDIS

WMS Conceptual Architecture
(system components)

BPM toolkit Workflow WMS run-time
– process view Development toolkit system and tools
– organization view – graphical design tool – scheduler
– data view – developer’s workbench – task managers/interfaces
– re-engineering analyzer – testing tool – processing entities
– TQM advisor
– simulation tool – monitoring tool
– ... – tracking tool
– ...
– reporting tool
– ...



LSDIS

Process Modeling Methodologies

There are many methodologies ...
Communication-based methodologies stem from Winograd/Flores
“Conversation for Action Model” [WF87]
1.preparation - a customer requests an action to be performed or a per-
former offers to do some action
2.negotiation - both customer and performer agree on the action to be per-
formed and define the terms of satisfaction
3.performance - the action is performed according to the terms established
4.acceptance - the customer reports satisfaction (or dissatisfaction) with
the action
Figure 1.

preparation negotiation

Customer Workflow Loop Performer

acceptance performance

[2], [Georgakopoulos, Hornick and Sheth 94]


LSDIS

Process Modeling Methodologies.. continued

Example of Communication-based Model:
Modeling Materials Procurement Process

investigator procurement
Procure Materials office

Verify Status accounts
office

vendors
Get Bids

Place Order vendor

[2], [Georgakopoulos, Hornick and Sheth 94]


LSDIS

Process Modeling Methodologies.. continued

Activity-based methodologies focus on modeling the work instead
of modelling the commitments among humans.

Example of Activity based process modeling:

Procure Materials
task nesting
Verify Status Get Bids Place Order

Process modeling does not capture
signiﬁcant computational aspects


LSDIS

Process modeling to Workﬂow Implementation--
an example (Action WorkFlow)

Process Modeling Analyst

Application Builder

Implementation Implementation
Manager
on Lotus Notes on SQL Server



LSDIS

Workﬂow Modeling:
The example of METEOR model

start task task task end
task
filter

Aux. Sys.
interface
interface
proc. interface
entity proc.
entity
proc.
entity

METEOR: Managing End-To-End OpeRations
[Krishnakumar and Sheth 94]


LSDIS About the environment:
Types of Tasks

• user tasks involving humans in processing task
• application tasks:
• scripts involving terminal emulations to remote systems
• predefined interfaces to legacy application systems (e.g.,
Bellcore “contracts”)
• stored procedure calls
• client programs or servers invoking other servers
• database transactions

[Krishnakumar and Sheth 94]


LSDIS

About the environment
Processing Entities

• humans (may appear as a GUI; may use document/image
processing systems and applications)
• script interpreters and compilers (for processing scripts and
application programs)
• (legacy) application systems
• servers in client-server and transaction processing systems
• DBMSs

[Rusinkiewicz and Sheth 94, Krishnakumar and Sheth 94]


LSDIS

About the environment
Types of Interfaces

• RPC and t-RPC mechanisms using transaction processing
systems
• queue managers
• proprietary workstation to mainframe interfaces for
– “contracts”
– terminal emulation
• (distributed computing/communication infrastructure: CORBA,
DCE, Notes-like)

Workﬂow management can be seen as a new
distributed computing paradigm...
[Sheth and Krishnakumar 94]


LSDIS

Workﬂow Model and WMS wish list
(Requirements and Features)
• Modeling heterogeneous tasks
– task behavior/structure: externally visible states of the task,
initial state, termination states, significant events and their
attributes
– task inputs and outputs
– task (operation) semantics, e.g., compatibility, relaxed
isolation
• Modeling Interfaces and Processing Entities:
– type of interface/processing entity:
communication infrastructur(s) and associated APIs
– interface/processing entity (system) properties/semantics--
e.g., isolation granularity, order preservation, idempotency,
monotonicity

[Krishnakumar and Sheth 94/95, Sheth and Rusinkiewicz 93/94]]


LSDIS

• Coordination and Inter-relationships: Routing, Rules, Policies,
Practices, ..
• Inter-task dependencies
– state-based
– value-based: I/O objects and external variables
• Roles
• Work-lists: Work-prioritizing, Dynamic Work Distribution
• Data Management
– different task formats: message, contract, form, transaction;
EDI;
use of auxiliary systems for complex data manipulation
– different types of data: structured, text, image, voice,
video,...

[Krishnakumar and Sheth 94/95, Sheth and Rusinkiewicz 93/94, Dayal and Shan 93]


LSDIS

• Dynamic Aspects
– processing entity not known at design time
– new tasks can be added dynamically
– multiple concurrent invocation of the same task types
– ...
• Intra- and Inter-workflow Execution requirements:
– failure atomicity (A)
– execution atomicity (I)
– workflow recovery
– inter-workflow concurrency

[Krishnakumar and Sheth 94/95, Sheth and Rusinkiewicz 93/94, Dayal and Shan 93] 38


LSDIS

• support for long running workflows and tasks
• Error Handling
– Systems Errors
– Logical Errors
• Forward Recovery
• Monitoring
• Status tracking
• Reporting



LSDIS

Some Technical Challenges

• Different types of tasks => homogeneous modeling; modeling
execution behavior
• Correct and Executable (hence well defined) specifications and
correct and safe execution (including recovery)
• Heterogeneous processing environments and systems =>
semantics of applications and processing entities, their impact
on correct execution and performance
• Performance- many more messages/tasks in “application/
operation automation” as compared to “office/user task
automation”



LSDIS

Modeling Heterogeneous Tasks
(Task Structures)
Different state transition diagrams for different types of tasks
representing what is observable and what is controllable
by the WMS (i.e., can WMS enable that transition)

Initial
start
Initial Executing
Initial
start start done

Executing Executing
abort Done
fail done abort commit prepared
Prepared
Failed Done Aborted Committed commit
abort
A non-transactional task A transactional task Aborted Committed

An open 2PC transactional task

[Attie et al 93, Rusinkiewicz & Sheth 93, Sheth and Krishnakumar 94]]


LSDIS

Intertask Dependencies
Preconditions for initiating each scheduler-controllable transition
in a task.
Klein’s primitives [KL91]:
• Order Dependency: e1 < e2.
If both e1 and e2 occur, then e1 precedes e2.
• Existence Dependency: e1 -> e2.
If event e1 occurs sometimes, then event e2 also occurs
sometimes.
– Conditional Existence Dependency [KL91]: e1 -> (e2 -> e3)
Examples from multidatabase transaction models:
• Commit Dependency [CR92]: cmB < cmA
• Abort Dependency [CR92]: abB -> abA

[Attie et al 93, also see ACTA [Chrysanthis & Ramamritham 92], Georgakopoulos et al 94, Bilris et al 94,...]


LSDIS

There are many ways to model/specify dependencies, routing, pol-
icies, etc.

Examples of the types of dependencies from database (extended
transaction model) literature include, execution dependencies,
data/value dependencies, temporal dependencies. For example,
Flexible Transactions [Elmagarmid et al 90], ConTracts [Reuter 89],
ACTA [Chrysanthis and Ramamritham 92], Multitransactions [Gar-
cia-Molina et al 90], Multidatabase Transactions [Rusinkiewicz et al
92, Mauro thesis 1993], DOM [Georgakopoulos et al 94]....

Rule-based (ECA) specification [Dayal et al., others] is popular,
especially in research.



LSDIS

Simple Workﬂow Example

Compound Task task B
Initial
task A task A task C
(SD1,DD1)
Initial Initial Initial
Executing

Executing Executing Executing
(SD3,DD3)
Failed Completed

Failed Completed Failed Completed (SD2,DD2) Failed Completed



LSDIS

Another Example
Task Graph
DELETE
BOOKING

delete decrement update
booking summary alarm
(dB) (ds) (u?a)

increment update
summary alarm
(is) (u?a)

->
->
<
s(dB) -> s(dS)
c(ds) -> s(u?a)
c(iS) -> s(u?a)
(a(dB) & c(dS)) -> s(iS)
-> (a(dB) < d(dS)) -> a(dS)
&
->
[Woelk et al 93]



LSDIS A somewhat complex example
CKT-Type_1
SO
start

executing

abort done

AGG_task_1 ADD_COMPONENTS NEW_ADD

ROUTE=YES “CHG_GR”

ROUTE=NO
NEW_SWITCH
SEGMENT-1

SEGMENT-2

SEGMENT-3



LSDIS

Desirable Speciﬁcation Language Features
• definition of individual tasks (basic operation definition)
• support for application as well as use tasks (incl. transactions
and nonelectronic operations)
• state-based and value based intertask dependencies and data
management (control and data flow definitions)
• failure and exception handling
• business rules and constraints
• security and role resolution

[Dayal and Shan 93 (terms in parentheses), Krishnakumar and Sheth 94,]


LSDIS

Several Approaches to Language Specification
• Based on Extended Transaction Models (e.g., [ASSET [Biliris et al 94]),
based on rule-based specification,
based on logic-based specification
• Extending Multidatabase Query Language (e.g., MSQL extensions [Rusinkiewicz
et al])

• Extending a script or “agent-based” language (e.g., ConTract/APRICOT
[Watcher & Reuter 92, Schwenkreis 93], work at MCC-Carnot/InfoSleuth)

• Extending general programming languages (e.g., as in Tranactional-C [see
Encina manuals], or IPL [Chen et al 93, Bukhres et al 95])

• Develop a Enterprise-wide Multi-system Application
Development Environment (tasks in different languages,
executed through/by different interfaces/processing entities) (e.g.,
Graphical Intefrace -> METEOR “intermediate-level” sub-languages)

• Add graphical interface and visual programming paradigm to
the above



LSDIS

An Approach to Specification
METEOR (Sub-)Languages

start task task
task end
task
filter WFSL
TSL Aux. Sys.
interface
interface
proc. interface
entity proc.
entity
proc.
entity

WFSL: WorkFlow Specification Language
TSL: Task Specification Language
[Sheth and Krishnakumar 94]


LSDIS

Components of WFSL (partial)
• Task types: task structures, data input/output
• Task classes, Task instances
• Inter-task dependencies (logical error handling)
• Data exchange statements
• Filter (interface def.)
Components of TSL (partial)
• processing entity specific statements
• statements for revealing task structures
• statements for identifying interfaces and dealing with systems
errors

Languages can be targeted for end user programming or
developers. For example, WFSL and TSL are “intermediate”
languages targeted to developers/administrators.
[Krishnakumar and Sheth 94/95]



LSDIS
Run-time Architecture
(METEOR Approach)
Application
Developer
and
System
Analyst
USER
Work flow
Workflow initiation, Specification
Workflow monitoring and
Workflow Group Simulation
Workflow
Controller

TP Sys.
TP Sys. TP Sys.
TP Sys. Log

Open_2PC User
Tran. Contract Script
. Task Task Programs

TP Sys. Log Log Log Log Task Logs

DBMS QMS Term. Interfaces
Resource Mgr. Emulator

DBMS OSS OSS GUI Proc. Entities

[Krishnakumar and Sheth 94/95]


LSDIS

Enforceable Dependencies
• Dependencies may not be enforceable.
For example, ab(A) -> cm(B)

• Event attributes determine whether a dependency is enforceable.
For example,
– e1 -> e2 is run-time enforceable if
rejectable(e1) [delay e1 until e2 is submitted, reject e1 if
task 2 terminated without submitting e2],
or forcible(e2) [force execution of e2 when e1 is accepted
for execution].
– e1 < e2 is run-time enforceable if
rejectable(e1) [let e2 be executed when it is submitted,
thereafter reject e1 if submitted],
or delayable(e2) [delay e2 until either e1 has been accepted
for execution, or task 1 has terminated without issuing
e1].
[Attie et al 93]


LSDIS

Scheduling Approaches
• Based on Petri-net Models [Elmagarmid et al 90]
• Executor for Flex. Trans. in a logically parallel language L.0
[Ansari et 92]

• Interpreter of MDB transaction specification Language (VLP)
[Kuehn et al 91]

• Interpreter of ECA rules [Dayal et al 92]
• Games vs. Nature [Rusinkiewicz et al 92]
• Fine-state Automata [Jin et al 93]
• Scheduling and enforcing intertask dependencies using
temporal propositional logic and finite automata [Attie et al 93]
• Scheduling through Distributed Events [Singh and Tomlinson 94]

[Rusinkeiwicz and Sheth 94]


LSDIS

Scheduler/Controller Implementations

• Centralized (e.g., [Attie et al 93])
• Distributed (e.g., [Singh and Tomlinson 94])
• Scheduler per Workflow (e.g., [Jin et al 94])
• Scheduling by Workflow Objects (objects/tasks that carry state
info.)-- “ambulatory” (i.e., INCA-style [Barbara et al 94])



LSDIS

A Prototype Scheduler
(a centralized approach)

Submitted Requests Accepted Requests
Task
Agents
& event notiﬁcations Scheduler Dispatcher
Rejected Requests

Delayed
Requests
Re-attempt
Queries Replies Execution

Dependency Pending
Automata Set

[Attie et al 93]


LSDIS

Correctness & Execution Requirements
• Executable/ run-time enforceable specifications
• Scheduling
– correctness (no violation of intertask dependencies)
– safety (progress towards acceptable states)
– termination
• Recovery
– forward recovery
• Concurrency Control
– serializability ??

[Attie et al 93, Georgakopoulos et al 93, Krishnakumar and Sheth 94]



LSDIS

Transactional Workﬂow--
What it is and is not
Transactional workflows (try to) address application specific
and user-defined correctness, reliability, and functionality
requirements.
Transactional workflows share the objectives of some
extended/relaxed transaction models about selective
relaxation of transactional properties based on application
semantics.

... the term is likely to evolve, as it has
signiﬁcant appeal. For example, see DOM and Exotica projects ...

[Early use: Sheth & Rusinkiewicz 93, Rusinkiewicz and Sheth 94, Georgakopoulos et al 94]
[Additional discussions: Georgokopoulos, Hornick & Sheth 94/95, Krishnakumar & Sheth 94/95, Mohan et al 95]


LSDIS

Transactional workflows does not imply workflows are similar/
equivalent to DB transactions or support all ACID transaction
properties. Usually WMSs do not support consistency of data
across multiple databases, especially when there are failures.
Typically WMSs do not support some of the important features
supported by TP Monitors (e.g., concurrency control,
backward recovery, consistency of data). WMSs today do not
support concurrency control similar to those involved between
“transaction groups” in TP monitors. WMS applicationsoften
rely on local concurrency control.



LSDIS

A WMS may provide transactional properties to support forward
recovery, and/or use system and application semantics to support
semantic-based “correct” multi-system application execution.
Example levels of transactional support a WMS may provide are:
– use of TM concepts/techniques (log input/output, before
image, compensation...) to enable forward recovery and
failure atomicity
– part of a workflow has transactional properties (extended
transactional model with component transactions)
– support a “general” two phase commit (WMS schedule may
provide commit coordination) or interface with an external
commit coordinator.



LSDIS

A WMS may use transaction management technology, such as
– transactional-RPC between two components of a WMS
(e.g., scheduler and task manager),
– an external commit coordinator
– XA-like protocol between task manager and resource
manager (Interface/Proc. Ent.).
Scheduler

Task
Application Manager

Interface/
Proc. Ent.



LSDIS

Application/Task and System Semantics
to simplify CC and Recovery Management

Semantics (Application/Task, System) Impact (CC: Con. Control, R: Recovery)
limited commutativity (apply) fewer exclusive locks (CC)
relaxed isolation (appl) no global commitment (CC)
order preservation + rigorousness (sys) early release of locks (CC)
idempotency (sys) resubmit transactions (R)
+ monotonicity roll-forward recovery (R)

[Jin et al 93, Jin et al 94]


LSDIS

Enabling technologies and standards

DCE
CORBA, OLE/COM
Notes
X/OPEN TxRPC, ...
STDL
EDI
....
SIGs in some of the standardization bodies may address
workflow issues. For example, Common Facilities in CORBA
may address some workflow issues.



LSDIS

Transaction Monitor as a building block
Advantages second generation TP-monitors (e.g., Encina):
– Ease of implementing fault tolerance: Transactional-RPCs,
utilities such as Queue Managers or Structured File
Systems
– Limited support for persistence of server state
Disadvantages:
– Lack of interoperability between monitors
– Products still lack good performance, stability, lack of ease
of use/administration, OR
Problems with support for state persistence and
multi-threading



LSDIS

CORBA as a Building Block
Advantages
• Distributed Computing Infrastructure with several features.
• Support for distributed client-server system on different
hardware and operating system platforms:
ORBeline-- SunOS, Solaris, HP/UX, IBM/AIX, OSF,
Unixware, MS-Windows, Windos-NT, etc.;
Orbix-- Windows NT,Unix, etc.;
ObjectBroker-- MS-windows, Unix, Mac, OpenVMS, OS/2.
• Unified support for all data types defined in CORBA.
• Support for low-level data format transformations between
different systems.
• Multiple concurrent invocation of tasks.
Most ORBs support multi-threading.
• Dynamic Interface Invocation.



LSDIS

CORBA as a Building Block ... continued
Advantages (continued)
• Error Handling.
Support for System Exceptions and User Exceptions
(variable level of support by different products).
• Security Service.
Permission for every object; additional services (access
permissions as user-programmed filters or at method
invocation)
• Reliability/Fault tolerance.
Varied support, outside CORBA: ORBeline’s smart agent
tracks all object & clients, notifies failures, reroutes lost data



LSDIS

CORBA as a Building Block ... continued
Disadvantages/Problems
• Lack of interoperability between different commercial ORBs
and/or other distributed infrastructure.
Some exceptions: DOE--Orbix; Orbix--Tuxedo/MS OLE/
ISIS-RDO; ObjectBroker--OLE-COM/DDE; ORBeline--??
• Lack of access to Legacy Applications.
Some exceptions: ObjectBroker-- script servers; DOE --
wrapper?
• Limited Mapping of IDL to different languages.
Orbix-- C++; ORBeline-- C++; ObjectBroker-- C++;
HyperDesk-- C++, DOE-- C++ and C?
• Lack of transaction management support.
Not part of core specification. Common Facilities
Architecture tries to build transaction support on ORB.



LSDIS

Lotus Notes as Building Block
Advantages
• supports client-server application development
• supports and incorporates across several hardware platforms:
Windows, NT, OS/2, Solaris, AIX, SCO/ HP Unix, Macintosh
• supports multiple network protocols (TCP/IP, Ethernet, IPX,
NetBIOS, AppleTalk, Token Ring)
• comprehensive email application included
• support for enhanced email and document routing
• provides a consistent interface for all applications written for
Notes
• ease of use for end users
• large user base



LSDIS

Lotus Notes as Building Block ... continued
• supports multimedia data: formatted text, graphics, audio and
video objects may be embedded in Notes documents
• remote access of data
– users may dial up or log in across a network
• provides secure access to data
– kerberos based data encryption; password protection
• limited replication of databases allowed
• can work with other applications (through OLE in Windows)
• Notes API provides a good basis for creating workflow
applications

Notes provides a good infrastructure to build a WMS for
Administrative and Ad-hoc workflows.



LSDIS

Lotus Notes as Building Block ... continued
Disadvantages/deficiencies
• no support for transaction processing
– no support for ACID properties
– lack of locking mechanism
– latency in replication
• no real time collaboration support
– no conferencing/ shared screen support
• no native support for integrating legacy applications
• supports only the Notes database format

Currently Notes lacks good support for implementing
Production workflows requiring integration with
heterogenous information systems and transaction
support.


LSDIS

Research Projects and Prototypes on
Workﬂow and Related Issues
(a partial list)
APRICOT (Germany),
METEOR (Bellcore, Georgia, UofH),
Interbase (Purdue),
ASSET (Bell Labs),
TSME/DOM (GTE Lab),
Pegasus (HP Lab),
TriGSflow (Linz, Austria), Exotica (IBM Almaden),
Aachen, INRIA, ETH ...
Earlier projects: ETM (DEC), Carnot (MCC), INCA (MITL),



LSDIS

Multi-paradigm Workﬂows
Workflow applications in large/complex enterprises and those
spanning multiple enterprises require support for multiple
paradigms in terms of:
• Types of workflows: production, ad-hoc,...
• Communication infrastructures:
– Async (e-mail, document flow/work-group based, message
based)
– Sync (PRC, t-RPC, ...)
– local-area -- internet - wireless
• Computing Structures/Semantics: e.g., transactions in
Electronic Commerce, Transaction Processing Systems, and
DBMSs



LSDIS

Going Forward (commercial technology:
Development vs. Market Models

A1 An A1 An A1 An
W1 Wn WMS WMS
Infrastructure Infrastructure I1 In
Vertical Multi-paradigm
Horizontal
(infrastructure)
WMS: different features,
same infrastructure

A: Market/Application Domain (Healthcare, Financial, Mfg.,...)
W: Workﬂow Management System
I: Infrastructure



LSDIS

Trends/Standardization Efforts

Horizontal “Interoperability” Focus
– Workflow Coalition-- lack of “information system”
perspective and “transaction” support so far

Vertical “Market” Focus
– not yet started, but likely to start soon-- Healthcare,
Finance, Manufacturing
– SIGs are forming


Infrastructure components for
Multi-paradigm WMS

Component infrastructures for
future “multi-paradigm” workflow
management systems:
Trans.
Workﬂow – e-mail
CTM/ETM
– internet
DTP
- Encina
Workﬂow
Software
– Lotus Notes
Distributed Proc. – CORBA
Infrastructure Groupware e-mail
- CORBA, DCE, Support
- Lotus Notes
internet
– Transaction Monitors
X.400, X.500


LSDIS

A Small List of Research Challenges

• Model: multiple views of what is modeled, when to use
transaction properties/features, correctness issues
• Language: ease of specification vs. features; logical error
handling; use of visual programming
• Development: next generation enterpirse application
development scenario (multi-system applications running within
and across business enterprises), testing, simulation
• Run-time System: error handling, failure handling/recovery,
correctness, heterogeneous objects, scalability (e.g.,
scheduling for environment with many concurrent workflows),
performance
• Standards: plenty of relevant efforts, what is useful now?


Conclusions
• New paradigm for distributed computing? Perhaps it is the
way to provide glue to handle legacy systems, and to
to support migration/evolution.
• Technology related to business processes and
applications-- better relevance and visibility than
heterogeneous DDBMS and extended transactions;
still database and transaction management have
important roles to play.


LSDIS

Brief biography of the Tutorial Speaker:

Dr. Amit Sheth directs the Large Scale Distributed Information Systems (LSDIS) Lab and is an Associ-
ate Professor of Computer Science at the University of Georgia. Earlier he worked for nine years in the
R&D labs at Bellcore, Unisys, and Honeywell. He has lead projects on heterogeneous DDBMS, factory
information system, integration of AI-database systems (BrAID), transactional workflows (PROMT and
METEOR), federated database tools (BERDI and TAILOR), multidatabase consistency, and data qual-
ity (Q-Data). Dr. Sheth has published over 75 papers, given over 45 invited talks and 14 tutorials, and
lead two international conferences and a workshop as a General/Program (Co-)Chair. He has also
served twice as an ACM Lecturer, has been on over twenty five program and organization committees,
and is on the editorial board of four journals.

The LSDIS lab maintains very active collaboration with industry, and has won significant projects in the
areas of interoperable information system and workflow management (under the Healthcare Informa-
tion Infrastructure Program awarded by NIST) and global information system and management of het-
erogeneous digital data (awarded in the Massive Digital Data Systems initiative). Industrial partners on
these projects are Bellcore, MCC and CHREF. The lab acknowledges sponsorship/industrial affiliation
of the HP Labs and the Persistence Software Inc.

http://www.cs.uga.edu/~amit



LSDIS

Partial Bibliography
Special Issues, Proceedings and Edited Collections:
[1] M. Hsu, Ed., Special Issue on Workflow and Extended Transaction Systems, Bulletin of the Technical Committee on Data Engi-
neering (IEEE Computer Society), 16 (2), June 1993.
[2] T. While and L. Fischer, New Tools for New Times: The Workflow Paradigm-- The Impact of Information Technology on Busi-
ness Process Reengineering, Future Strategies Inc., Book Division, Alameda, CA, 1994.
[3] O. Bukhres and e. Kueshn, Eds., Special Issue on Software Support for Work Flow Management, Distributed and Parallel Data-
bases -- An International Journal, 3 (2), April 1995.
Papers on Workﬂow and Multisystem Applications: (* Paper accessible at: http://www.cs.uga.edu/LSDIS/)
[4] * M. Ansari, L. Ness, M. Rusinkiewicz, and A. Sheth, "Using Flexible Transactions to Support Multi-system Telecommunication
Applications," in Proc of the 18th Int’l Conf on Very Large Data Bases, August 1992.
[5] * P. Attie, M. Singh, A. Sheth, and M. Rusinkiewicz, "Specifying and Enforcing Intertask Dependencies," in Proc. of the 19th
Intl Conf. on Very Large Data Bases, August 1993.
[6] * Y. Breitbart, A. Deacon, H.-J. Schek, A. Sheth, and G. Weikum, “Merging Application-centric and Data-centric Approaches
to Support Transaction-oriented Multi-system Workflows,” in SIGMOD Record 22 (3), September 1993.
[7] * D. Georgakopoulos, M. Hornick and A. Sheth, “An Overview of Workflow Management: From Process Modeling to Infra-
structure for Automation, Technical Report TR-CS-94-003, LSDIS Lab, Dept. of CS, Univ. of GA, November 1994. Also, in [3].
[8] R. Gunthor, "Extended Transaction Processing Based on Dependency Rules," in Proc. of the RIDE-IMS '93: Intl. Workshop on
Multidatabase Systems, April 1993.
[9] F-J. Fritz, Workflow implementation based on the R/3 reference model, SAP AG (Report/Manuscript), 1995?
[10] D. Hollingsworth, “The Workflow Reference Model,” Workflow Management Coalition, TC00-1003, December 1994.
[11] M. Hsu and C. Kleissner, ObjectFlow: Towards a Process Management Infrastructure,” submitted for publication.
[12] P. Korzeniowski, “Workflow Software Automates Processes,” Software Magazine, February, 1993.
[13] * N. Krishnakumar and A. Sheth, “Managing Heterogeneous Multi-system Tasks to Support Enterprise-wide Operations,” Tech-
nical Report TR-CS-94-002, LSDIS Lab, Dept. of CS, Univ. of GA, September 1994.A (shorter) version appears in [3].



LSDIS

[14] F. Leymann and W. Altenhuber, “Managing Business Processes as an Information Resource,” IBM Systems Journal, 33 (2),
1994.
[15] F. Leymann and D. Roller, “Business Process Management with FlowMark,” Proceedings of IEEE Compcon, March 1994.
[16] R. Marshak, “Software to Support BPR - The value of Capturing Process Definitions”, Workgroup Computing Report, Patricia
Seybold Group, Vol. 17, No. 7, July, 1994.
[17] S. McCready, “There is more than one kind of Work-flow Software,” Computerworld, November 2, 1992.
[18] C. Mohan, G. Alonso, R. Gunthor, and M. Kamath, “Exotica: A Research Perspective on workflow Management Systems,” Bul-
letin of the Technical Committee on Data Engineering (IEEE Computer Society), 18 (1), March 1995.
[19] * Rusinkiewicz and A. Sheth, "Specification and Execution of Transactional Workflows," in the Modern Database Sys-
tems: The Object Model, Interoperability, and Beyond, W. Kim, Ed., Addison-Wesley, 1994.
[20] T. Smith, “The Future of Work flow Software,” INFORM, April 1993.
[21] * D. Woelk, P. Attie, P. Cannata, G. Meridith, A. Sheth, M. Singh, and C. Tomlinson, "Task Scheduling using Intertask Depen-
dencies in Carnot," in Proc. of ACM SIGMOD Conf. on Management of Data, May 1993.
For additional references and pointers to products, see for example papers in [1] and [2].



LSDIS

A few papers on relaxed transactions (model and language issues only):
A. Biliris, S. Dar, N. Gehani, H.V. Jagadish and K. Ramamritham,"ASSET: A system for supporting extended transactions," in Proc. of
the 1994 ACM SIGMOD Conference on Management of Data, 1994.
J. Chen, O. Bukhres, and A. Elmagarmid, “IPL: A Multidatabase Transaction Specification Language,” In Proc. of the 13th Intl. Conf.
on Distributed Computing Systems, Pittsburgh, PA, May 1993.
P. Chrysanthis and K. Ramamritham, "A Formalism for Extended Transaction Models," in Proc. of the 17th VLDB Conference, 1991.
U. Dayal, M. Hsu, and R. Ladin, "A Transactional Model for Long-Running Activities," in Proc. of the 17th Int'l Conference on Very
Large Data Bases, September 1991.
A. Elmagarmid, Y. Leu, W. Litwin, and M. Rusinkiewicz, “A Multidatabase Transaction Model for InterBase,” Proceedings of the 16th
International Conference on VLDB, 1990.
H. Garcia-Molina, D. Gawlick, J. Klein, K. Kleissner, and K. Salem, "Coordinating Multi-transaction Activities," Technical Report CS-
TR-247-90, Princeton University, February 1990.
D.Georgakopoulos, M. Hornick, P. Krychniak, and F. Manola, "Specification and Management of Extended Transactions in a Program-
mable Transaction Environment, in Proc. of the Intl. Conf. on Data Engineering, February 1994.
W. Jin, N. Krishnakumar, L. Ness, M. Rusinkiewicz, and A. Sheth, “Multidatabase transactions in the telecommunications environment:
Modeling, Concurrency Control and Recovery Issues,” Bellcore Technical Memorandum, September 1993.
E. Kuehn, F. Puntigam, and A. Elmagarmid, “Transaction Specification in Multidatabase Systems Based on Parallel Logic Program-
ming,” in Proc. of the RIDE-IMS '91: Intl. Workshop on Interoperability in Multidatabase Systems, April, 1991.
J. Klein, "Advanced Rule Driven Transaction Management," in Proc. of the IEEE COMPCON, 1991.
F. Schwenkreis. APRICOTS - A prototype implementation of a ConTract system: Management of the Control Flow and the Communi-
cations System," in Proc. 12th Symposium on Reliable Distributed Systems, 1993.



LSDIS

Additional items that may be covered in this tutorial if time permits ...

screens from some workflow design tools
detailed example of process modeling and workflow modeling
comparison of some products wrt to their models and features
description and comparisons of some research prototypes
language issues in more detials
run-time issues in more detail


Workﬂow Automation: Applications, Technology and Research

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