Grid-based Collaboration
Minjun Wang
Department of Electrical Engineering and Computer Science
Syracuse University
Advisor: Professor Geoffrey C. Fox Indiana University
Outline
Part I.
Motivation, Background, Research
Issues, and Our Approach
Part II.
Experimental Systems
Part III.
Theoretical Framework
Motivation
• Collaboration over the Internet is becoming more and more popular and important.
– Online conference, distance education, Learning, e-Science, e-Business, etc.
• A major reason for low adoption of collaboration tools is network problems including dropped packets and firewalls
• Further apart from shared display, often hard to share “events” needed to define changes needed to synchronize collaborating clients
• Grids are built as Internet scale managed Web Services with “two-level programming model”
– Services are conventional (Java, C++, Fortran, Python, Perl) programs wrapped in WSDL and exposing changes as
messages
– Services are composed with workflow (defined by industry standard BPEL)
• Messages between services handled by Message Oriented
Middleware style infrastructure generalizing Enterprise Service Buses
Background
• Attractive to build Collaboration around Grid services with
(SOAP) messages capturing “change events” needed to relate collaborating clients
• Then we need to handle events in a powerful fashion
• This is role of NaradaBrokering (Shrideep Pallickara, Syracuse PhD 2001) which is Message Oriented Middleware that
supports Web Service messaging, UDP and TCP, many event delivery models
– Dominant Grid messaging system: downloaded 1000 times a year – JMS Java Message Service is the “Java world” equivalent
– Mule is typical open source Enterprise Service Bus
• Our work uses NaradaBrokering but conclusions are not sensitive to this choice.
Fundamental Research Issues
• This approach “reduces” problem of building collaborative applications to that of building applications as Grid services
• However essentially all applications are neither written as Web services nor do they have needed changes exposed as
messages
• These ideas have been investigated in two 2005 Syracuse PhD theses
– Ahmet Uyar: Collaborative Audio-video conferencing
– Xiaohong Qiu: Grid (Web) services as a model for desktop applications using Batik SVG browser as model
• In this thesis we investigate models for building services and evaluate their effectiveness in producing collaborative Grid services
– This is fundamental issue discussed in this thesis
• We also need to develop a theoretical framework (Deterministic Finite Automata) and a general client service interaction model (in thesis but not discussed in slides)
Practical Points and Performance
• Our work verified results of earlier theses that Grid messaging produced negligible overhead as its intrinsic overhead (2
millisecond today decreasing with Moore’s law) is an order of magnitude less than times relevant to Human perception (see Uyar thesis and 30 ms frame rate)
• Early Web service technologies produce significant overhead but this is reduced in next generation (Axis 2) of web service container (Axis 2 from Apache is just released with about 5 ms overhead)
• Other Indiana theses (Oh and Aydin) have explored overhead due to SOAP messages and shown it can be made small by transmitting “binary SOAP” i.e. messages compatible with SOAP Infoset but not using traditional angle bracket format – We can use this fast Infoset approach and transmit
messages as text compatible with SOAP message semantics
Shared Event vs. Shared Display
• We use Shared Event Model in this research • Reduce network traffic
• Insure efficient utilizations of the computing capabilities.
• Increase freedom in collaboration as to what event to or not to collaborate on
• Investigate new application models compared to other work (such as TangoInteractive)
• Shared Display has been implemented in Collaborative Grid formalism and is handled well by NaradaBrokering (only tested to 50 clients) as long as clients can support needed network bandwidth
• Available in VNC and commercial systems
• Can’t support dynamic applications well and failed for
fusion physicists sharing IDL-based scientific visualizations
Roles in Collaboration
• Master, Participant, Administrator and Observer are typical roles
• In online gaming such as chess one exchanges master role between white and black
• Virtual classroom typically has teacher as master and administrator able to give capabilities to students
• Tokens specify role of clients
• Token passing between the Master and Participant allow the interchange of their roles and is implemented as messages transmitted by Grid messaging system
– Roles in Grid Collaboration very similar to those in traditional collaboration
A Collaboration Structure
Collaboration in Peer-to-peer Grid Systems
•
Grid Systems typically have identified “central”
servers and “thin” peer clients.
– Our current work can be deployed in such a way that the message broker in “central” and clients as the “thin” peers
•
P2P systems combine client and server (service) in
the same machine.
– The Master sends messages to Participants; any
Participant can send messages to other Participants, with the message brokers in a P2P way (Future Work).
•
Peer-to-peer Grid Systems.
– A hybrid of the above two; a Participant can get the
Outline
Part I.
Motivation, Background, Research
Issues, and Our Approach
Part II.
Experimental Systems
Introduction
Part III.
Theoretical Framework
Part IV.
Conclusions and Future Work
Collaborative Services
• As described, Grid and web services do NOT change programming model inside a service – they changes the interaction model
between services for messaging and workflow
• We wish to investigate programming models for a service that easily expose the needed change events to define the state movement of collaborating automata
• Shared display exposes changes in framebuffer produced by an application
• Another model (investigated in Qiu’s thesis) captures user input events (such as mouse events) and shares these
• We look at sharing interactions defined by two different component models for desktop applications – PowerPoint and Impress
• And we look at the (best from our research!) sharing of events in applications built using a language IDL where events built into language
Outline
Part I.
Motivation, Background, Research
Issues, and Our Approach
Part II.
Experimental Systems
Collaborative PowerPoint
Part III.
Theoretical Framework
Part IV.
Conclusions and Future Work
Collaborative PowerPoint Applications
•
Collaboration roles in terms of the Master client and
the Participant client
•
Software model
•
Distributed Component Object Model (DCOM)
•
Identify events in the Master
•
Render event messages in the Participant
The Mechanism for the Master
Client to Capture Events
The Events Available in PowerPoint Interface
The Events Missing in PowerPoint
AnimationClipPlayed, MoviesPlayed, AnimationFilePlayed, etc.
Events about animations and transitions
SoundClipPlayed, SoundFilePlayed, etc.
Events about sounds
MouseOver, MouseClicked,
MouseDoubleClicked, KeyDown, KeyUp, KeyStroke, etc.
Lessons Learned
• Events are not first-class, and very limited
•
Only in “EApplication” IDispatch interface
• Difficult to make the application
collaborative
•
DCOM, JNI, Events captured in hexadecimal
format
• Can not collaborate on all events
Outline
Part I.
Motivation, Background, Research
Issues, and Our Approach
Part II.
Experimental Systems
Collaborative IDL
Part III.
Theoretical Framework
Collaborative IDL Applications
• IDL is widely used in research, commerce, and education. • Engineering, medical physics, astronomical and space
science, and earth science.
• Complete and proper definitions of event structures in IDL • Structures, levels, configurations
• Elegant mechanisms of widget programming of IDL
• Widgets in IDL correspond to GUIs in Java, such as buttons, sliders
• Experiments in different Event Distribution Modes • Notifying structure vs. Polling Structure
• Success in making real-life IDL applications collaborative • Collaboration experience on ReviewPlus package from
General Atomics of U.S.A
• System currently being evaluated for deployment in fusion research
• Small company RSI in Colorado that markets IDL interested in (a production version of) our research
The Master Client
• GUI building and
managing and
event handling
• Master client
connects and
sends event
messages to the
message broker
via the IDL-Java
bridge
The Participant Client in Notifying Structure
• Callable IDL and
JNI
Generating of a Shared Library
• A C program calls
the IDL routines
directly through
Callable IDL
technology
• A shared library
(libCallableIDL.so)
is generated from
the C program.
The Participant Client in Polling
Structure
• Critical section in interface of NB
• The client polling the
event flag and getting event messages • The client
A Sample of Event Structures Used
in IDL Widget Programming
Advantages and Disadvantages
The Notifying Structure • Advantages:
– Not changing anything in the IDL and the NB
systems.
– Development is in the
collaborative applications.
• Disadvantages:
– complicated and
inconsistent in the code shapes
– time and efforts cost is high – It is difficult to develop
The Polling Structure • Advantages:
– Simple
– Practical and feasible for large IDL applications to be collaborative
– Prevents data loss
• Disadvantages:
– Have to change the
underlying systems (e.g., an interface of NB).
A Performance Test from the Collaborative
ReviewPlus Applications
Time of bounce-back in milliseconds between
the Master Client (San Diego, CA) and the
NB (Bloomington, IN)
• Mean: 130.72 (milliseconds)
• Standard Deviation: 10.18 (milliseconds)
• Standard Error: 1.41 (milliseconds)
Lessons Learned
• Events are first-class
• Amount of event generating can be tuned.
•
e.g. (1) The keyword
DRAG
for function
WIDGET_SLIDER
; (2) Keywords
All_Event
and
Return_Event
for text field widget.
• Elegant mechanisms of widget
A General Approach for Collaboration
in IDL (Compiler)
Another General Approach for Collaboration in ID
(Embedded Collaboration Objects)
• Keep user IDL applications “untouched” (or almost “untouched”) • Accommodate the IDL system routines and libraries to satisfy the
collaboration needs.
• The IDL system library routine “XMANAGER.pro”
• provides the main event loop and management of widgets. • not called much; usually once a widget program.
• It is possible for us to deal with all the event handling and
processing in this routine and all other related system routines to achieve collaboration.
• Make a version for the Master client
(XMANAGER_MASTER.pro) and a version for the Participant client (XMANAGER_PARTICIPANT.pro).
• Deploy them to the end user IDL applications, replace
Outline
Part I.
Motivation, Background, Research
Issues, and Our Approach
Part II.
Experimental Systems
Collaborative Impress
Part III.
Theoretical Framework
Part IV.
Conclusions and Future Work
Collaborative Impress Applications
Technologies for Universal Programming/Application • Universal Network Object (UNO)
– a component technology.
• Diverse Programming Environment
– C++, Java, Java Script, Visual Basic, VBScript, and Delphi; on platforms such as UNIX, Linux, and Windows.
• Fine-grained Application Programming Interfaces (API) – Open Office defines a comprehensive specification
describing its programmable features, and it is fine-grained. • Frame-Controller-Model (FCM) Paradigm
– The Model is the document object
The Master Client
• It sets up the
remote bridge and takes control of the programming
features of Office via FCM paradigm • It registers
listeners at the remote bridge to listen to events fired at the Office server.
The Participating Client
• Creates a
remote bridge
• Gets control of
the FCM to
call
functionality in
controlling the
rendering
Part of the Event Listener Interfaces and the Events
Lessons Learned
• Similar problems to those found in
collaborative PowerPoint
• Events are not first class. Events available
depends on the work of the OpenOffice
developers
•
e.g., the Impress “slide show” interfaces were
underdeveloped
• The labor in making the application
collaborative is high
Outline
Part I.
Motivation, Background, Research
Issues, and Our Approach
Part II.
Experimental Systems
Part III.
Theoretical Framework
Theoretical Framework for Collaboration
•
The Master client and Participant clients of each
prototype are collaboration entities.
•
The collaboration entities of a type play different
roles, and they are finite automaton-based in a
collaboration session.
•
The Master and Participant collaboration entities
have the same logic as to the state transitions
on events, and get to the same state at the end
of the process of each event.
The Finite Automaton
• The standard five-tuple notation A = (Q, Σ, δ, q0, F), where
• A is the name of the automaton;
• Q is the finite set of states of the automaton; • Σ is the finite set of input symbols;
• q0 is the start state;
• F is the finite set of final or accepting states, which is a subset of Q • δ is the transition function, which takes as parameters a state from Q
and a symbol from Σ, and returns a state in Q for Deterministic Finite Automata (DFA), or a set of states from Q for Nondeterministic Finite Automaton (NFA).
• Deterministic Finite Automata (DFA) are suitable for modeling the collaboration entities in a shared event collaboration session.
• The meaning of this modeling:
– simple, clear, and consistent picture
– see through the differences between the entities
Characteristics of the DFA for Collaboration Entities
• The specialties in the set of input symbols Σ
– Traditionally, the symbols in Σ are alphabets, digits,
or any printable ASCII characters (e.g., a, b, c, 1, 2,
3, %, $, &).
– In our modeling, we define the symbols (or units) in
Σ to be event messages, which are independent
text strings
• “OpenFile;
Dir/filename
”, “Goto;
CertainSlide#
”,
“Previous”, “Next”
• “{Widget_Base;ID:10;TOP:8;HANDLER:10;X:123
;Y:456}”
• This is to use semantically complete event messages
as the basic units in Σ
A DFA Example in Collaborative
PowerPoint Applications
A presentation file that has three slides 1, 2, & 3.
•
Q = {q0, q1, q2, q3, q4}, where
– q0 is the state when the application is started;
– q1, q2, q3 are the states for slide 1, 2, and 3, respectively; – q4 is the state when the application is ended.
•
Σ = {a0, a1, a2, a3, a4, a5, a6}, with
– a0 = “Openfile;C:/file1.ppt” (open it), – a1 = “Goto;1” (go to slide 1),
– a2 = “Goto;2” (go to slide 2), – a3 = “Goto;3” (go to slide 3),
– a4 = “Exit” (the application exits),
– a5 = “Previous” (go to the previous slide), – a6 = “Next” (go to the next slide).
•
The start state is q0.
A DFA Example in Collaborative
PowerPoint Applications
Outline
Part I.
Motivation, Background, Research
Issues, and Our Approach
Part II.
Experimental Systems
Part III.
Theoretical Framework
Conclusions
q
We have developed the theoretical framework in terms of
Deterministic Finite Automaton for modeling collaboration.
q
We have developed three prototypes to investigate
different approaches to programming services in shared
event model for collaborative Grids
q
It is important to make useful standalone applications
collaborate universally, and find the efficient and elegant
ways to make them collaborative, with regard to
architectures, event structures, and mechanisms of widget
programming.
q
We have succeeded in three different programming
models but conclude that languages like IDL, where the
complete and proper definitions of event structures are
supplied and elegant mechanisms of widget programming
are guaranteed, are more suitable than traditional
Contribution
q
We have developed the theoretical
framework in terms of Deterministic Finite
Automaton for modeling collaboration.
q
We have made useful standalone
applications collaborate universally, have
found the efficient and elegant ways to
make them collaborative, and have
investigated different approaches to
Future Work
• New Categories
– Microsoft Office suite: Access, Excel, Publisher, and Word.
– OpenOffice suite: Drawing, Spreadsheet, HTML Document, and
Text Document.
– IDL world: developed user applications
– Investigate other programming and component models to see which behave like IDL.
• New Requirements
– from the General Atomics Affiliation, Inc. of USA
• New Approaches to Design General Collaborative IDL Systems
– Compiler Application
– Embedded Collaboration Objects
Publications
Conference Articles
• [1] Minjun Wang, Geoffrey Fox, and Marlon Pierce, “Collaboration Entities on Deterministic Finite Automata”, Proceedings of the 2006 International Symposium on Collaborative Technologies and Systems (CTS 2006), IEEE Computer Society, Las Vegas, Nevada, USA, May 14-17, 2006, pp. 26-37. • [2] Minjun Wang, Geoffrey Fox, and Marlon Pierce, “Thin Client
Collaboration Web Services”, Proceedings of the Advanced International Conference on Telecommunications and International Conference on Internet and Web Applications and Services (AICT/ICIW 2006), IEEE
Computer Society, Guadeloupe, French Caribbean, February 23-25, 2006, CD-ROM, Product Number E2522, ISBN 0-7695-2522-9, Library of
Congress 2005937760.
• [3] Minjun Wang, Geoffrey Fox, and Marlon Pierce, “Instantiations of
Shared Event Model in Grid-based Collaboration”, Proceedings of the 9th World Multi-Conference on Systemics, Cybernetics and Informatics
(WMSCI 2005), International Institute of Informatics and Systemics, Orlando, Florida, USA, July 10-13, 2005, Volume III, pp. 11-18.
• [4] Minjun Wang, Geoffrey Fox, and Marlon Pierce, “Grid-based
Publications (2)
Conference Articles
• [5] Minjun Wang and Geoffrey Fox, “Design of a Collaborative System” (for Impress of Open Office), Proceedings of the IASTED International
Conference on Knowledge Sharing and Collaborative Engineering (KSCE 2004), ACTA Press, St. Thomas, US Virgin Islands, November 22-24, 2004, pp. 192-200.
• [6] Minjun Wang, Geoffrey Fox, and Shrideep Pallickara, “New Tools in Education”, Proceedings of the Seventh IASTED International Conference on Computers and Advanced Technology in Education (CATE 2004), ACTA Press, Kauai, Hawaii, USA, August 16-18, 2004, pp. 218-223.
• [7] Minjun Wang, Geoffrey C. Fox, and Shrideep Pallickara, “A
Demonstration of Collaborative Web Services and Peer-to-peer Grids”,
Proceedings of ITCC 2004 International Conference on Information
Technology: Coding and Computing, IEEE Computer Society, Las Vegas, Nevada, USA, April 5-7, 2004, Volume II, pp. 62-67.
• [8] Geoffrey Fox, Hasan Bulut, Kangseok Kim, Sung-Hoon Ko, Sangmi Lee, Sangyoon Oh, Shrideep Pallickara, Xiaohong Qiu, Ahmet Uyar, Minjun
Wang, and Wenjun Wu, “Collaborative Web Services and Peer-to-Peer Grids”, Proceedings of 2003 Collaborative Technologies Symposium (CTS’03), Orlando, USA, 2003.
• [9] Sangmi Lee, Geoffrey Fox, Sunghoon Ko, Minjun Wang, and Xiaohong Qiu, “Ubiquitous Access for Collaborative Information System Using SVG”,
Proceedings of SVGopen conference, Zurich, Switzerland, July 2002.
Publications (3)
Journal Articles
• [1] Minjun Wang, Geoffrey Fox, and Shrideep Pallickara, “Demonstrations of Collaborative Web Services and Peer-to-Peer Grids”, Journal of Digital Information Management, Digital Information Research Foundation, Adyar, Chennai, India, June 2004, Volume 2, Number 2, pp. 93-96. (Special Issue of selected papers from the IEEE ITCC 2004)
Technical Reports
• [1] Minjun Wang, “A Description of the Implementation of Collaborative ReviewPlus”, Technical Report, July 19, 2005.
• [2] Minjun Wang, Geoffrey Fox, and Marlon Pierce, “General Collaboration Structures for Interactive Data Language Applications”, Technical Report, May 2005.
Book Contribution
• [1] Geoffrey C. Fox, Dennis Gannon, Sung-Hoon Ko, Sangmi Lee, Shrideep Pallickara, Marlon Pierce, Xiaohong Qiu, Xi Rao, Ahmet Uyar, Minjun
Wang, and Wenjun Wu, “Peer-to-peer Grids”, Chapter 18 in Grid
