39 research outputs found
Contract representation for validation and run time monitoring
PhD ThesisOrganisations are increasingly using the Internet to offer their own services and to utilise the
services of others. This naturally leads to resource sharing across organisational boundaries.
Nevertheless, organisations will require their interactions with other organisations to be
strictly controlled. In the paper-based world, business interactions, information exchange and
sharing have been conducted under the control of contracts that the organisations sign. The
world of electronic business needs to emulate electronic equivalents of the contract based
business management practices.
This thesis examines how a 'conventional' contract can be converted into its
electronic equivalent and how it can be used for controlling business interactions taking place
through computer messages. To implement a contract electronically, a conventional text
contract needs to be described in a mathematically precise notation so that the description can
be subjected to rigorous analysis and freed from the ambiguities that the original humanoriented
text is likely to contain. Furthermore, a suitable run time infrastructure is required for
monitoring the executable version of the contract.
To address these issues, this thesis describes how standard conventional contracts can
be converted into Finite State Machines (FSMs). It is illustrated how to map the rights and
obligations extracted from the clauses of the contract into the states, transition and output
functions, and input and output symbols of a FSM.
The thesis then goes on to develop a list of correctness properties that a typical
executable business contract should satisfy. A contract model should be validated against
safety properties, which specify situations that the contract must not get into (such as
deadlocks, unreachable states .... etc), and liveness properties, which detail qualities that
would be desirable for the contract to contain (responsiveness, accessibility .... etc). The FSM
description can then be subjected to model checking. This is demonstrated with the aid of
examples using the Promela language and the Spin validator.
Subsequently, the FSM representation can be used to ensure that the clauses
stipulated in the contract are observed when the contract is executed. The requirements of a
suitable run time infrastructure for monitoring contract compliance are discussed and a
prototype middleware implementation is presented.UK Engineering and Physical Sciences Research
Council (EPSRC)
Contract representation for validation and run time monitoring
Organisations are increasingly using the Internet to offer their own services and to utilise the services of others. This naturally leads to resource sharing across organisational boundaries. Nevertheless, organisations will require their interactions with other organisations to be strictly controlled. In the paper-based world, business interactions, information exchange and sharing have been conducted under the control of contracts that the organisations sign. The world of electronic business needs to emulate electronic equivalents of the contract based business management practices. This thesis examines how a 'conventional' contract can be converted into its electronic equivalent and how it can be used for controlling business interactions taking place through computer messages. To implement a contract electronically, a conventional text contract needs to be described in a mathematically precise notation so that the description can be subjected to rigorous analysis and freed from the ambiguities that the original humanoriented text is likely to contain. Furthermore, a suitable run time infrastructure is required for monitoring the executable version of the contract. To address these issues, this thesis describes how standard conventional contracts can be converted into Finite State Machines (FSMs). It is illustrated how to map the rights and obligations extracted from the clauses of the contract into the states, transition and output functions, and input and output symbols of a FSM. The thesis then goes on to develop a list of correctness properties that a typical executable business contract should satisfy. A contract model should be validated against safety properties, which specify situations that the contract must not get into (such as deadlocks, unreachable states ... etc), and liveness properties, which detail qualities that would be desirable for the contract to contain (responsiveness, accessibility ... etc). The FSM description can then be subjected to model checking. This is demonstrated with the aid of examples using the Promela language and the Spin validator. Subsequently, the FSM representation can be used to ensure that the clauses stipulated in the contract are observed when the contract is executed. The requirements of a suitable run time infrastructure for monitoring contract compliance are discussed and a prototype middleware implementation is presented.EThOS - Electronic Theses Online ServiceEngineering and Physical Sciences Research Council (EPSRC)GBUnited Kingdo
A Model-Based Machine Learning Approach for Assessing the Performance of Blockchain Applications
The recent advancement of Blockchain technology consolidates its status as a
viable alternative for various domains. However, evaluating the performance of
blockchain applications can be challenging due to the underlying
infrastructure's complexity and distributed nature. Therefore, a reliable
modelling approach is needed to boost Blockchain-based applications'
development and evaluation. While simulation-based solutions have been
researched, machine learning (ML) model-based techniques are rarely discussed
in conjunction with evaluating blockchain application performance. Our novel
research makes use of two ML model-based methods. Firstly, we train a
nearest neighbour (NN) and support vector machine (SVM) to predict
blockchain performance using predetermined configuration parameters. Secondly,
we employ the salp swarm optimization (SO) ML model which enables the
investigation of optimal blockchain configurations for achieving the required
performance level. We use rough set theory to enhance SO, hereafter called ISO,
which we demonstrate to prove achieving an accurate recommendation of optimal
parameter configurations; despite uncertainty. Finally, statistical comparisons
indicate that our models have a competitive edge. The NN model outperforms
SVM by 5\% and the ISO also demonstrates a reduction of 4\% inaccuracy
deviation compared to regular SO
Implementation of Smart Contracts Using Hybrid Architectures with On- and Off-Blockchain Components
Recently, decentralised (on-blockchain) platforms have emerged to complement
centralised (off-blockchain) platforms for the implementation of automated,
digital (smart) contracts. However, neither alternative can individually
satisfy the requirements of a large class of applications. On-blockchain
platforms suffer from scalability, performance, transaction costs and other
limitations. Off-blockchain platforms are afflicted by drawbacks due to their
dependence on single trusted third parties. We argue that in several
application areas, hybrid platforms composed from the integration of on- and
off-blockchain platforms are more able to support smart contracts that deliver
the desired quality of service (QoS). Hybrid architectures are largely
unexplored. To help cover the gap, in this paper we discuss the implementation
of smart contracts on hybrid architectures. As a proof of concept, we show how
a smart contract can be split and executed partially on an off-blockchain
contract compliance checker and partially on the Rinkeby Ethereum network. To
test the solution, we expose it to sequences of contractual operations
generated mechanically by a contract validator tool.Comment: 12 pages, 7 figure
Tracking material reuse across construction supply chains
Material reuse and recycling plays a key role in reducing carbon emissions in the architecture and construction sector. A “Material Passport” (MP) is a record describing how a material is used throughout its lifetime, from genesis to termination, recording operations carried out on the material. The granularity of information recorded in a MP can vary, however ensuring that this provenance trail remains immutable is a key requirement. The benefits of using a MP, operations carried out on a MP, and recording of transactions within a distributed Blockchain (parachain) is described. A scenario is used to illustrate how the proposed approach can be used in practice
A blockchain-based SLA monitoring and compliance assessment for IoT ecosystems
A Service Level Agreement (SLA) establishes the trustworthiness of service providers and consumers in several domains; including the Internet of Things (IoT). Given the proliferation of Blockchain technology, we find it compelling to reconsider the assumption of trust and centralised governance typically practised in SLA management including monitoring, compliance assessment, and penalty enforcement. Therefore, we argue that, such critical tasks should be operated by blockchain-based smart contracts in a non-repudiable manner beyond the influence of any SLA party. This paper envisions an IoT scenario wherein a firefighting station outsources end-to-end IoT operations to a specialised service provider. The contractual relationship between them is governed by an SLA which stipulates a set of quality requirements and violation consequences. The main contribution of this paper lies in designing, deploying and empirically experimenting a novel blockchain-based SLA monitoring and compliance assessment framework in the context of IoT. This is done by utilising Hyperledger Fabric (HLF), an enterprise-grade blockchain technology. Our work highlights a set of considerations and best practice at two sides, the IoT application monitoring-side and the blockchain-side. Moreover, it experimentally validates the reliability of the proposed monitoring approach, which collects relevant metrics from each IoT component and examines them against the quality requirements stated in the SLA. Finally, we propose a novel design for smart contracts at the blockchain-side, analyse and benchmark the performance, and demonstrate that the new design proves to successfully handle Multiversion Concurrency Control (MVCC) conflicts typically encountered in blockchain applications, while maintaining sound throughput and latency.Validerad;2023;Nivå 2;2023-04-06 (hanlid);Funder: The Engineering and Physical Sciences Research Council, EPSRC (EP/V042017/1)</p