Papers on promise theory
Promise theory offers a different focus on modelling systems composed of
autonomous components. Rather than modelling what happens, we claim that
one should also study what is claimed.
- Voluntary cooperation in pervasive computing services
Proceedings of the Nineteenth Systems Administration Conference
(LISA XIX) (USENIX Association: Berkeley, CA)}, page 143, 2005
The advent of pervasive computing is moving us towards a new
paradigm for computing in terms of {\em ad hoc} services. This carries
with it a certain risk, from a security and management viewpoint.
Users become increasingly responsible for their own hosts. A form of
service transaction based on minimal trust is discussed. A proof of
concept implementation of non-demand (voluntary) services is discussed
for pervasive computing environments. `Voluntary Remote Procedure
Call' is a test-implementation of the proposed protocol integrated into
cfengine, to show how voluntary cooperation of nodes can allow a
cautious exchange of collaborative services, based on minimal trust.
An analysis of implementation approaches followed by a discussion of
the desirability of this technology is presented.
- An Approach to Understanding Policy Based on Autonomy and Voluntary Cooperation
Lecture Notes on Computer Science, 3775:97--108, 2005
Presently, there is no satisfactory model for dealing with
political autonomy of agents in policy based management. A theory of atomic
policy units called `promises' is therefore discussed. Using promises,
a global authority is not required to build conventional management
abstractions, but work is needed to bind peers into a traditional
authoritative structure. The construction of promises is precise, if
tedious, but can be simplified graphically to reason about the
distributed effect of autonomous policy. Immediate applications
include resolving the problem of policy conflicts in autonomous
networks.
- Pervasive Computer Management: A Model of Network Policy with Local Autonomy
(Technical report 2004,5,6)
We present a model for incorporating autonomy into network
management in order to discuss the consistency and stability of system
policy in a pervasive computer setting. Our synthesis uses graph
theoretical ideas, algebras and iterated games to evaluate the
probability of stable and constist policy in a network region. In
particular we recognize the necessity of including a social model in a
theory of pervasive computing. The resulting model may be interpreted
as a generalized distributed policy maintenance model, and it shown
that the theory is that of a logically ad hoc network.
- Voluntary Economic Cooperation in Policy Based Management
(Technical report 2004,5,6)
Systems with decentralized authority are sometimes considered to be
`unmanaged' or even unmanageable. Promise theory is an approach to
policy that assumes complete decentralization of
authority. Cooperation between agents or systems is entirely
voluntary, so why would agents cooperate in forming policy? By
exhibiting the relationship between promise theory and game theory, we
propose that there is a natural economic incentive for cooperation in
distributed systems with autonomous control.
Our results are especially applicable to the
analysis of policy in a Service Oriented Architecture. We derive
minimal requirements for the existence of stable
Agreements between agents.
- Pervasive Computer Management: A Smart Mall Scenario Using Promise Theory
Proceedings of MACE 2006 p. 133, Multicon Lecture Notes ISBN 987-3-930736-05-8
A plausible pervasive computing scenario is explored using promise
theory, in which the emphasis is on management in the face of
individual node autonomy. We use promises both as a means of model
specification and as a complementary eye glass for interpreting and
understanding the actual behaviour. We show how structure can be
understood, faults can be found and successful interactions are
represented as bargaining games. The method of eigenvector centrality
is used to locate the important and vulnerable places within the
resulting collaborative network.
- On the Stability of Adaptive
Service Level Agreements
IEEE Transactions on Network and Service Management, 2, 2006
We consider some implications of non-linear feedback,
due to policy combinatorics, on policy-based management of networked
services. We pay special attention to the case where the monitoring of
certain aspects of Service Level Agreements is used to alter future
policy dynamically, according to a control feedback scheme. Using two
simple models, we show that non-linear policies are generally unstable
to service provision, i.e. provide no reliable service levels (QoS).
Hence we conclude that automated control by policy-rule combinatorics
can damage quality of service goals.
- A Promise Theory Approach to Collaborative Power Reduction in a Pervasive Computing Environment
Lecture Notes on Computer Science, 4159 p615-624 2006
A grid-like environment may be constructed from ad hoc
processing devices, including portable battery-powered
devices. Battery lifetime is a current limitation here. In this paper
we propose policies for minimizing power consumption using voluntary
collaboration between the autonomously controlled nodes.
We exploit the quadratic relationship between processor
clock-speed and power consumption to identify
processing devices which can be slowed down to save energy
while maintaining an overall computational performance across a
collaboration of nodes.
- Promise theory -- a model of autonomous objects for pervasive computing and swarms
Winner of the World Class Technology Summit 06, (proceedings) 2006
The theory of promises describes policy governed services, in
a framework of completely autonomous agents, which assist one another
by voluntary cooperation alone. We propose this as a framework for
analysing realistic models of modern networking, and as a formal model for
swarm intelligence.
- Local and Global Trust Based on the Concept of Promises
(submitted to IJIS) 2006
We use the notion of a promise to define local trust between
agents possessing autonomous decision-making. An agent is trustworthy if it
is expected that it will keep a promise. This definition satisfies
most commonplace meanings of trust. Reputation is an estimation
of value that is passed on from agent to agent.
Our definition distinguishes types of trust, for different
behaviours, and decouples the concept of agent reliability from the
behaviour on which the judgement is based. We show, however, that
trust is fundamentally heuristic, as it provides insufficient
information for agents to make a rational judgement. A global
trustworthiness, or {\em community trust} can be defined by a
proportional, self-consistent voting process, as a weighted
eigenvector-centrality function of the promise theoretical graph.
- Modelling Next Generation Configuration Management Tools
Proceedings of the XX Large Installation System Administration Conference, LISA 2006. p131-147
There are several current theoretical models used to discuss
configuration management, including aspects, closures, and promises.
We examine how these models relate to one another, and develop a
overall theoretical framework within which to discuss configuration
management solutions. We apply this framework to classify the capabilities
of current tools, and develop requirements for the next generation of
configuration management tools.
- Autonomic Computing Approximated by Fixed-Point Promises
Proceedings of First IEEE International Workshop on Modelling Autonomic Communication Environments (MACE2006). p197-222, Multicon Lecture Notes ISBN 987-3-930736-05-8
We use the concept of promises to develop a service oriented
abstraction of the primitive operations that make an autonomic
computer system. Convergent behaviour does not depend on centralized
control. We summarize necessary and sufficient conditions for
maintaining a convergently enforced policy without sacrificing
autonomy of decision, and we discuss whether the idea of versioning control
or ``rollback'' is compatible with an autonomic framework.
- A Promise Theory View on the Policies of Object Orientation and the Service Oriented Architecture
Technical report 2005,6
Object orientation (OO) and Service Oriented Architecture
(SOA) are two approaches to software design. By modelling these using
Promise Theory we show that we can easily accomodates SOA principles
into program modelling. We also show that promise theory can help to
resolve ambiguities in OO design, and we resolve a case in which UML
semantics do not offer sufficient guidance to determine a natural
structure in a program. Our approach offers some simple clarity on
the various meanings of inheritance policy and the Liskov substitution
principle.
- A Process Algebra based Framework for
Promise Theory
Technical report 2007
We present a process algebra based approach to formalize the interactions of com-
puting devices such as the representation of policies and the resolution of
conflicts.
As an example we specify how promises may be used in coming to an agreement
regarding a simple though practical transportation problem.
Key words: Software/program verification, formal methods D.2.4
- Promises and cfengine
Technical report 2005, not for publication
We apply promise theory to the configuration management system cfengine in order to
criticize its current structure and derive a new improved design.
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