Mobile Computing PSV3 2001 Fall Uppsala University Dept. Informaation Science Kenji Taguchi

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Mobile Computing(PSV3)2001 FallUppsala
UniversityDept. Informaation ScienceKenji
Taguchi
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Introduction (1)

• Name Kenji Taguchi
• Birth Tokyo, Japan
• Research Interests in General
• Formal Methods,
• Formal Theory on Mobile Computation
• More info on myself
• http//www.dis.uu.se/kenjit/
• Kenji.Taguchi_at_dis.uu.se

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Introduction (2)

• In Industry 12 years
• Research Institute for Artificial Intelligence
• Implementations of expert systems and their
  shells (mainly in charge of the design and
  implementation of inference engine)
• Consulting firm
• Feasibility studies on AI systems (various expert
  systems such as scheduling, process control and
  autonomous intelligent robot, etc)
• Software Company
• Research and Development of AI systems (machine
  learning, rule compiler), program synthesis and
  transformation and formal methods
• In Academia 5th year (full-time)

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Goal of the course

• To study
• a new programming paradigm,
• its underlying notions,
• programming models and styles
• for mobile agents and web programming

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The topics which are not dealt with in this course

• AI related issues
• problem solving by intelligent agents
• agent interactions
• Mobile phones
• hardware devices
• protocols

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Course Structure

• Lectures
• Introductory explanation on topics
• Seminars
• Readings and discussions
• Lab works
• programming

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Background knowledge (1)

• There are no well-established theories, models
  and programming languages for world-wide
  computing systems and mobile agents systems.
• Neither real-world applications nor de facto
  standards whatsoever.
• I should remind you that this course is very
  experimental.
• So you must read some recent articles written by
  leading researchers
• and use very experimental programming languages

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Background knowledge (2)

• Some formal theories exist
• For instance,
• Ambient calculus (L. Cardelli and A. Gordon)
• Are they well-establised theories? No. But this
  will be answered in future (maybe in the next 10
  years).
• Those are highly theoretical, so we wont study
  them in this course.

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Why should we study this course?

• Maybe this form of computation will prevail the
  world in near future!
• Some Future Prospect
• Mobile Phones Java mobile (web) agents
• would provide various intelligent web-based
  assistances for
• travel booking,
• information retrieval,
• etc.,

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Course Pre-requisites

• We will use Aglets (Java API) for lab. work.
• Knowledge on Java is essential
• If you are an expert on Java programming, you are
  perfectly fitted in this course!
• Knowledge on programming environment is also a
  must
• Unix, emacs, shells, etc.,
• Knowledge on HTML is also required

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Seminars (1)

• World Wide Computing
• L. Cardelli,
• Wide Area Computation,
• ICALP99 LNCS1644, Springer, 99, pp10-24
• Mobile agents
• J. White,
• Mobile Agents White Paper,
• General Magic, 1996

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Seminars (2)

• Web Computing
• L. Cardelli, R. Davies,
• Service Combinators for Web Computing,
• IEEE Transactions on Software Engineering, Vol
  25, No 3, 1999, pp309-306
• Web Language
• T. Kistler, H. Marais,
• WebL - A Programming Language for the Web
• SRC Technical Note

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Lab Works

• You will study
• Aglets (Java API) for programming mobile agents
  systems
• Web Language for programming web
• You are divided into groups (2 to 3 members)
• Small assignments must be completed by each group

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Grading

• Lab. work (compulsory)
• Anyone who does not participate in lab. work will
  automatically fail
• Participation of seminars
• Final Exams

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What is mobile computing?

• Everyday life, mobile computing appears in many
  forms
• mobile phones,
• personal digital assistants (PDA),
• personal computers.
• Those are mainly hardware devices (supported by
  software system).

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Whats out there?

• Web
• So dominant.
• e-commerce
• Web-based world wide commerce
• Information Retrieval
• search information on the web

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Wish lists (1)

• I want to carry my PC to everywhere I go. Once
  it is plugged into a remote network, I would like
  to use the PC as well as all environments
  (applications, data, etc) which are provided by
  servers in the original network.

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Wish lists (1-1)
Firewall
NetworkB
networkA
Server
Server
PC
PC
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Wish lists (1-2)

• Current technology
• How to connect a PC to another network
• DHCP (Dynamic Host Configuration Protocol)
• How to use applications and data on a remote
  server
• Remote rogin, file transfer

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Wish lists (2)

• I want my program to find infomation
  automatically which I am looking for on the web.

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Wish lists (2-1)
World Wide Web
Lycos
PC
Yahoo
Web Browser
Search Engines
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Wish lists (2-2)
World Wide Web
Yahoo
Search Engines
robots
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Wish lists (2-3)

• Current technology
• Robots (Crawlers) on the web
• a program that automatically traverses the Webs
  hypertext structure by retrieving a document and
  recursively retrieving all documents that are
  referenced.
• not for a personal use
• this is for search engines such as Yahoo and
  Lycos, etc.
• Perhaps, a program which mimics manual operations
  of the web browser will serve as a personal
  search engine.

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Some history of Computer Science

• What were there before the Web?
• Network (remote) programming
• Socket
• Remote Procedural Call (RPC)

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History of remote programming (network
programming) (1)

• Communication between processes
• Socket

processB
processA
Local Kernel (OS)
Remote Kernel (OS)
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History of remote programming (network
programming) (2)

• RPC (Remote Procedural Calls)

Client function
Server function
Local Kernel (OS)
Remote Kernel (OS)
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Remote programming to Mobile computing

• Mobile computing is usually discussed at more
  abstract level

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Layers of Mobile Computing
Development Methods
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Metaphors in computing

• Object-Orientation
• Everything is an object. Interactions between
  them are achieved by message passing.
• Mobile agents
• An agent (program) will travel around the network
  to accomplish a task

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Evolution of mobility

• Mobile codes
• Mobile threads
• Mobile processes
• Mobile (Migratory) applications

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Mobile codes (1)
Remote Computer
E.g., Down-loading mechanism of Java
Local Computer
Remark Java cannot send a code to a remote host.
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Mobile codes (2)
Remote Computer C
Remote Computer B
Remote Computer A
Remote Computer D
Local Computer
Remark Codes can move around the network.
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Mobile Threads
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Mobile Processes
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Mobile Applications
application
Remote Computer B
Remote Computer A
application
Remote Computer C
application
An application itself roams around the network
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Computational models and programming languages

• Computational models
• Canonical form of computation
• The lambda calculus,
• Abstract Machines (Turing machine,etc)
• Logic,
• Process Algebras (CCS, CSP, the pi calculus),
  Mobile Calculi (Ambients, etc)
• Programming languages
• How to program computers
• consists of
• data structures
• control structures
• loop, if then else, while
• other primitive constructs
• parallel

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Computational models vs Programming Languages

• The lambda calculus Functional
  Programming Languages
• Standard ML, Lisp, etc.,
• Logic Logic Programming Languages
• Prolog
• The pi calculus Process-oriented Programming
  Languages
• PICT

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To Do List for Today

• Please purchase a collection of articles at the
  Student Office (Expedition),
• Please send me an e-mail about your group. The
  group must consists of 2 to 3 members,
• Read an article Wide Area Computation carefully
  and prepare for the discussion until the next
  seminar,
• Check out whether you have an account in the
  computer lab.