The GLOBAL DISTRIBUTED DIARY

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The GLOBAL DISTRIBUTED DIARY

• Department of Computer ScienceFaculty of Science
• University of Tromsø

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Problem domain

• The integration of mobile computers into the
  existing infrastructures, implies that each
  person uses a set of machines. At any moment, the
  most convenient/-productive machine will be
  chosen.
• Updates performed on one computer must be made
  available to the others in the set in order to
  satisfy data consistency constraints.

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Goal no. 1

• Address and devise solutions to the data
  consistency problems that arise when small,
  personal, variably connected mobile machines are
  integrated into an infrastructure for data
  sharing dominated by stationary, well connected
  computers.

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Goal no. 2

• Devise a distributed application (a distributed
  diary), along with appropriate system support
  (which includes security), that handles
  consistent read/write sharing of replicated data
  between a large set of heterogeneous, variably
  connected computers.

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Sub-goals (AB)

• State the application requirements (incl.
  availability, and consistency requirem.
  trade-offs) necessary to construct the GDD.
• Develop protocols capturing the consistency
  issues that allows programmers to express the
  appl.s consistency constraints easily, and that
  have suitable impl. in a variable conn. env. with
  many resource poor nodes.

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Sub-goals (CD)

• Device an infrastructure that can safeguard
  security and privacy for this environment in
  general and in this application in particular.
• Explore the integration of int. agents into the
  distributed diary, incl. examination of how int.
  agents can extend and/or substitute the
  distributed diary functions, and how such agents
  can meet the security requir.

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Method

• Primarily experimental. The research is driven
  by a distributed applic.the GDD.
• The GDD will include replication management,
  security, authentication, authorisation, and
  privacy, all which allows experimentation with
  key problem areas.

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Overview

• The GDD application
• GDD distributed data repository
• GDDsystem interface
• Security and privacy
• Integration of intelligent agents into the GDD

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The GDD application

• Develop the necessary requirements and
  fundamental design choices prior to the
  construction of the GDD, including requirements
  and trade-offs for
• availability and consistency of data
• distribution of messages and alarms
• Result requir. specification, design
  implementation of core parts of the GDD.

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GDD distributed data repository

• Replicated systems are usually based on the
  assumption that they are connected. In case of
  partition and conflicting updates, the
  correctness is based on progress in the majority
  partition.
• In the type of system we are considering, desired
  progress may well be initiated from a
  disconnected machine, that may be (part of) a
  minority partitioning of the GDD.

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GDD dist. data repository (cont.)

• Replication mgmt for fully replicated data
• Result a replic. mgmt scheme for fully
  replicated small size, discrete data items in the
  variable connected environ. of the GDD.
• Replic. mgmt for partially replicated data
• Result a replic. mgmt scheme for partially
  replic. large size, discrete and continuos data
  items suitable for the variab. conn. env.

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GDDsystem interface

• The interface between the GDD and system services
  must be designed such that is allows co-operation
  between the application and the system.
• Results how to construct flexible applic. that
  behave well over a system that provides varying
  resources and services, including dynamic and
  seamless switching between wired and wireless
  networks.

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GDDsystem interface (cont.)

• Flexibility and co-operation with system
• Result construction of a GDD that is able to
  exhibit flexibility in the face of variable
  resource provisions.
• Flexibility and co-operation with applic.
• Result a system that is able to exhibit
  flexibility in the face of variable resource
  provisions.

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Security and privacy

• We will investigate issues related to striking
  the balance between privacy and usability
• how to establish the existence and presence of
  principals in the system.
• how to facilitate delegation authorisation.
• Result a security and privacy system that will
  provide a balance between ensuring access to
  services the required privacy.

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Integration of intelligent agents

• Investigate how agents may behave and maybe
  improve the usability of the GDD
• how, if possible, intelligent agents can extend
  and/or substitute GDD tasks
• how, if possible, intelligent agents can meet
  the security requirements of the GDD
• Result how agents may behave and maybe improve
  the usability of the GDD.

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Expected deliverables (1996-2000)

• 2 Ph.D. (D.Sc.) candidates (1 GDD supp.)
• 7-12 M.Sc. (cand.scient.) (3-4 per year)
• 20 grad. engineers (siv.ing.) (5 per year)
• 5-10 journal papers
• 10-20 conference papers
• 10-20 visits at collaborators
• X popular science articles in newspapers ...

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Milestones
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Costs
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Status and results per 1997

• Prosjektansatte finansiert av NFR
• Research Scholar Dag Brattli (3.3.97-2.3.01)
• Postdoc Arne Helme (1.9.97-30.8.99)

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Results per 1997

• Desember 1996 Plan Res. Avvik Conf./ws
  papers 2 3 1 Cand.scient.stud 2 0 -2 Siv.ing.
  4 4 0 Travel UPisa 8 7 -1 July 1997
  Plan Res. Avvik Journal papers 1 2 1 Conf./ws
  papers 3 4 1 Cand.scient.stud 2 1 -1 Siv.ing.
  4 0 -4 Travel UPisa 4 1 -3 Travel
  UTwente 4 0 -4

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Systems constructed

• Applikasjon for sømnløs svitsjing mellom ether og
  radio-nett.
• Distribuert diary-applikasjon basert på FR
• Replikert versjon av File Repository (FR).
• PGPlib (PGP bibliotek).
• Verktøy for administrasjon av samarbeidende
  programvareagenter.
• Browser-SW for palmtop computers.

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Under construction

• Programmeringsgrensesnitt for FR.
• Sikkerhet mellom klienter-tjener og mellom
  replikerte tjenere i en FR-omgivelse.
• Brukermodell-baserte agenter.
• Samarbeidsstrategier for programvare-agenter
  (bl.a. som en utvidelse til GDD-applikasjonen).

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Publikasjoner 1996

• Konferanser
• Cao, W., Bian, C.-C., Hartvigsen, G. 1996.
  Cooperator-Base Task-Base for Agent Modeling
  the Virtual Secretary Approach. Proceedings of
  the 1996 AAAI Workshop on Agent Modeling
  (Portland, Oregon, August 4, 1996). Technical
  Report WS-96-02. Menlo Park, California AAAI
  Press, s. 105-111.
• Helme, A., Stabell-Kulø, T. (1996). Off-line
  Delegation in a File Repository. Presented at the
  1996 DIMACS Workshop on Trust Management in
  Distributed Systems, Rutgers University, October,
  1996.
• Tech.reports, etc.
• Stabell-Kulø, T. (1996). Security in the PASTA
  project. Technical Report no. 96-27, Department
  of Computer Science, University of Tromsø.

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Publikasjoner 1997

• TidsskrifterHelme, A., Stabell-Kulø, T. 1997.
  Security functions for a file repository.
  Operating System Review 31 (2 April), 3-8.
• Stabell-Kulø, T. 1997. Security and log
  structured file systems. Operating System Review
  31 (2 April), 3-8.
• Konferanser
• Brattli, D., Stabell-Kulø, T. 1997. A software
  network for mobile computers. Presented at
  Cabernet 3rd Plenary Workshop (Rennes, France,
  April 16-18, 1997).
• Bian, C-G., Cao, W., Hartvigsen, G. 1997. An
  Efficient Heuristic Search in a Large Multi-Agent
  System. Proceedings of the Fourteenth National
  Conference on Artificial Intelligence (AAAI-97),
  (July 27-31, 1997, Providence, Rhode Island),
  Menlo Park, California AAAI Press.

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Publikasjoner 1997

• Cao, W., Bian, C.-C., Hartvigsen, G. 1997.
  Achieving Efficient Cooperation in a Multi-Agent
  System the Twin-Base Modeling. Proceeding of
  Cooperative Information Agents DAI meets
  Database Systems (CIA'97) (Kiel, Germany,
  February 26-28, 1997). I P. Kandiza, M. Klusch
  (Eds.), Cooperative Information Agents. Lecture
  Notes in Computer Science 1202, Berlin
  Springer-Verlag, pp. 210-221.
• Cao, W., Bian, C.-G., Hartvigsen, G. 1997. An
  Organizational Approach to Efficient Cooperation
  in an Agent Society. Posters Proceedings at
  MAAMAW'97 (8th European Workshop on Modeling
  Autonomous Agents in a Multi-Agent World), (May
  13-16, 1997, Ronneby, Sweden), I M.Boman, W. Van
  de Velde, S.Hägg (Eds.), MAAMAW97 Posters
  Proceedings. ISRN HKR-RES--97/5--SE. Ronneby,
  Sweden Univ. of Karlskrona, pp. 23-34.

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