Ponder: Realising enterprise viewpoint concepts

This paper introduces the Ponder language for speciing distributed object enterprise concepts. Ponder, is a declarative language, which permits the specification of policies in terms of obligations, permissions and prohibitions and provides the means for defining roles, relationships and their configurations in nested communities. Ponder provides a concrete representation of most of the concepts of the Enterprise Viewpoint. The design of the language incorporates lessons drawn from several years of research on policy for security and distributed systems management as well as policy conflict analysis. The various language constructs are presented through a scenario for the operation, administration and maintenance of a mobile telecommunication network

Security and management policy specification

Accepted versio

Goals, Interpretations, and Policies in Information Systems Design

Current goal-oriented requirements engineering methods focus on the definition of optimal requirements that an information system needs to support in order to help its stakeholders to achieve their goals. But, the lack of systemic reasoning and disregard for questions of interpretation lead to insufficient attention given to activities and implicit policies affecting the definition of these goals. This results in the optimization of the goals to the their activities, their policies requirements for potentially inadequate goals. Our framework relates stakeholders and their interpreted constraints and capabilities. It enables requirements engineers to better understand the rationale for goals found through requirements elicitation techniques and shows that conflicting goals can be reconciled by understanding how they fit in a higher-level activity. This results in the formulation of a more adequate set of goals that the information system should support in order for the organization and stakeholders to perform their activities

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)

LifeWatch deliverable 5.1.3: Technical construction plan –Reference Model

The LifeWatch Reference Model (LifeWatch-RM) provides a common conceptual framework for understanding the significant relations and key characteristics of the Information and Communications Technologies (ICT) elements of LifeWatch that should appear consistently across different implementations. Its intention is to represent a common view of the ICT dimension between all those involved in and contributing to the LifeWatch Research Infrastructure and to provide guidelines for the construction and management process. The LifeWatch-RM defines a number of components and architectural concepts as a basis for the future LifeWatch Architecture. It is neither a blueprint nor does it define a technological mapping, but identifies some key aspects and components that should be present in the final implementation of the LifeWatch System

Model driven validation approach for enterprise architecture and motivation extensions

As the endorsement of Enterprise Architecture (EA) modelling continues to grow in diversity and complexity, management of its schema, artefacts, semantics and relationships has become an important business concern. To maintain agility and flexibility within competitive markets, organizations have also been compelled to explore ways of adjusting proactively to innovations, changes and complex events also by use of EA concepts to model business processes and strategies. Thus the need to ensure appropriate validation of EA taxonomies has been considered severally as an essential requirement for these processes in order to exert business motivation; relate information systems to technological infrastructure. However, since many taxonomies deployed today use widespread and disparate modelling methodologies, the possibility to adopt a generic validation approach remains a challenge. The proliferation of EA methodologies and perspectives has also led to intricacies in the formalization and validation of EA constructs as models often times have variant schematic interpretations. Thus, disparate implementations and inconsistent simulation of alignment between business architectures and heterogeneous application systems is common within the EA domain (Jonkers et al., 2003). In this research, the Model Driven Validation Approach (MDVA) is introduced. MDVA allows modelling of EA with validation attributes, formalization of the validation concepts and transformation of model artefacts to ontologies. The transformation simplifies querying based on motivation and constraints. As the extended methodology is grounded on the semiotics of existing tools, validation is executed using ubiquitous query language. The major contributions of this work are the extension of a metamodel of Business Layer of an EAF with Validation Element and the development of EAF model to ontology transformation Approach. With this innovation, domain-driven design and object-oriented analysis concepts are applied to achieve EAF model’s validation using ontology querying methodology. Additionally, the MDVA facilitates the traceability of EA artefacts using ontology graph patterns

Consistency in multi-viewpoint architectural design

This thesis presents a framework that aids in preserving consistency in multi-viewpoint designs. In a multi-viewpoint design each stakeholder constructs his own design part. We call each stakeholder’s design part the view of that stakeholder. To construct his view, a stakeholder has a viewpoint. This viewpoint defines the design concepts, the notation and the tool support that the stakeholder uses. The framework presented in this thesis focuses on architectural multiviewpoint design of distributed systems. A distributed system is a system of which the parts execute on different physical system nodes. Interaction between the system parts plays an important role in such systems. An example of a distributed system is a mobile communication network. In such a network, the parts of the system execute on e.g. the mobile telephones of the clients, the desktops of the employees of the network operator and the mobile access points. Architectural design is the area of design that focuses on higher levels of abstraction in the design process. The lowest level of abstraction that we consider is the level at which the system parts correspond to parts that can be deployed on communication middleware. Using our framework, consistency is preserved through inter-viewpoint relations and consistency rules that must be specified by the stakeholders. The stakeholders use inter-viewpoint relations to specify how one view relates to another and they use consistency rules to specify what rules must at least be satisfied in a consistent design. To aid in preserving consistency, our framework defines: – a common set of basic design concepts; – pre-defined inter-viewpoint relations; – pre-defined consistency rules; – a language to represent inter-viewpoint relations and consistency rules. The basic design concepts that the framework defines have been adopted from earlier work. These concepts were developed by carefully examining the area of distributed systems design. Using our framework, viewpoint-specific design concepts must be defined as compositions or specializations of these basic concepts. Hence, the basic concepts form a common vocabulary that the different stakeholders can use to understand each other’s designs. The framework pre-defines inter-viewpoint relations that can be reused to specify how one view relates to another. The two main types of inter-viewpoint relations that it pre-defines are: refinement relations and overlap relations. Refinement relations exist between views that (partly) consider the same design concerns at different levels of abstraction. Overlap relations exist between views that (partly) consider the same design concerns at the same level of abstraction. We derived the pre-defined relations by examining existing frameworks for multi-viewpoint design and extracting frequently occurring relations between viewpoints in these frameworks. If a pre-defined inter-viewpoint relation exists between two views, this implies that certain consistency rules must be satisfied. Specifically, if two views have a refinement relation, this implies that one must preserve the system properties specified by the other. If two views have an overlap relation, this implies that the two views must be equivalent with respect to the overlap that they have. Our framework pre-defines consistency rules that can be re-used to verify these properties. We define an architecture for tool-support to aid in specifying view relations and consistency rules and to check whether the specified consistency rules hold. The architecture contains the pre-defined relations and consistency rules, such that they can be re-used. As a case study for the framework we define adapted versions of the RM-ODP enterprise, computational and information viewpoints, using our framework. We define the concepts from these viewpoints as compositions of the basic concepts. Also, we define the relations between views from these viewpoints, as well as the corresponding consistency rules, using the relations and consistency rules that are pre-defined by the framework. The results of the case study support the claim that our framework aids in preserving consistency in multi-viewpoint designs

A new trajectory for spatial data infrastructure evolution in the developing world

Includes abstract.Includes bibliographical references (leaves 107-113).Spatial Data is a key resource in the development of cities. There is a lot of socio-economic potential that is locked away in spatial data holdings and this potential is unlocked by making the datasets widely available for use. Spatial Data Infrastructures (SDIs) have served this primary purpose; to make data accessible through the use of web based technologies. However, SDIs have not had their anticipated impact at local levels of governance. They have traditionally served as platforms that facilitate access to raw spatial datasets. They have not fully facilitated for the use of these datasets and therefore have attracted minimal attention from decision makers and users. This research suggests a new trajectory for SDI evolution; a trajectory that will allow them to evolve into more relevant platforms for confronting the urban crisis in developing nations and thereby ensuring that they have the societal impact that they are intended to. The research explores the characteristics of the mainstream efforts to counter urban crises in the developing world to determine how the new SDI should be re-conceptualised to more adequately assist in responding to the urban crisis. This leads to the incorporation of Evidence Based Practice (EBP) into SDI through the use of urban indicators and knowledge creation processes to reflect on the pressing societal issues. From the new SDI concept, an architectural design is implemented as a “proof of concept”. At the heart of this new concept is the SDIs ability to provide access to more than just raw spatial datasets but useful information products that are based on these data. This proves that EBP can be incorporated into SDI to make them more efficient in responding to the urban problems in developing nation and consequently more relevant Information Infrastructures for urban decision makers