An editor and transformation system for a Z animation case tool.

In order to remain competitive, modem systems developers are increasingly under pressure to produce software solutions to complex problems faster and cheaper, whilst at the same time maintaining a high level of quality in the delivered product. One of the key quality measures is the delivery of a system that meets the customer's requirements. Failure to meet the customer's requirements may engender significant re-design, which in turn will cost money, delay product introduction and may seriously damage the developer's credibility. For these reasons, the problem of developing a precise and unambiguous statement of requirements for a proposed system is perhaps one of the most challenging problems within software engineering today. Formal, model-based specification languages such as the Z notation have been widely adopted within the context of requirements engineering, to provide a vehicle for the development of precise and unambiguous specifications. However, the mathematical foundation upon which these notations are based often makes them unapproachable and difficult to assimilate by a non-specialist reader. The problem then faced is that if the customer cannot understand the semantics of the specification, how can the customer agree that the specification is indeed a true reflection of the requirements for the desired system? Several researchers have proposed that rapid prototyping and animation of specifications can be used to increase the customer's understanding of the formal specification. This is achieved by executing specification components on candidate data and observing that the behaviour is as expected. However this requires that the original formal specification be reliably transformed into a representation capable of being executed within a computer system. To achieve this aim requires the support of computer-based tools able to assist the requirements engineer in capturing, manipulating and transforming the formal specification in an efficient and consistent manner. This thesis describes the research and development of the TranZit tool, which is a Z notation editor, checker and transformation system. TranZit supports the efficient capture and maintenance of Z notation specifications using the Windows Graphical User Interface, supported by a suite of powerful language-driven features. In addition TranZit contains a highly integrated and optimised syntax and type checker, combining traditional compiler design techniques with innovative use of object-oriented data structures and methods, to assist the requirements engineer in ensuring the internal consistency of the captured specification. Most importantly, TranZit contains a novel transformation engine, which is capable of transforming a captured Z specification into an executable representation based on extensions to LISP, suitable for direct execution in an animation environment. This process is supported by an eclectic strategy combining automated transformation with user assistance, to overcome many of the well-documented problems associated with transforming non-executable clauses in formal specifications

Отношение истории и динамика схем баз данных СУБД DIM

The article is devoted to a type dynamics for a new object DBMS DIM [1, 2] and the schemes evolution of its databases.Рассматривается задача динамики типов для новой объектной СУБД DIM [1, 2] и связанная с ней динамика схем ее баз данных

Managing Schema Change in an Heterogeneous Environment

Change is inevitable even for persistent information. Effectively managing change of persistent information, which includes the specification, execution and the maintenance of any derived information, is critical and must be addressed by all database systems. Today, for every data model there exists a well-defined set of change primitives that can alter both the structure (the schema) and the data. Several proposals also exist for incrementally propagating a primitive change to any derived information (or view). However, existing support is lacking in two ways. First, change primitives as presented in literature are very limiting in terms of their capabilities allowing users to simply add or remove schema elements. More complex types of changes such the merging or splitting of schema elements are not supported in a principled manner. Second, algorithms for maintaining derived information often do not account for the potential heterogeneity between the source and the target. The goal of this dissertation is to provide solutions that address these two key issues. The first part of this dissertation addresses the challenge of expressing a rich complex set of changes. We propose the SERF (Schema Evolution through an Extensible, Re-usable and Flexible) framework that allows users to perform a wide range of complex user-defined schema transformations. Our approach combines existing schema evolution primitives using OQL (object query language) as the glue logic. Within the context of this work, we look at the different domains in which SERF can be applied, including web site management. To further enrich our framework, we also investigate the optimization and verification of SERF transformations. The second part of this dissertation addresses the problem of maintaining views in the face of source changes when the source and the view are not in the same data model. With today\u27s increasing heterogeneity in information structure, it is critical that maintenance of views addresses the data model boundaries. However, view definitions that go across data models are limited to hard-coded algorithms, thereby making it difficult to develop general maintenance algorithms. We provide a two-step solution for this problem. We have developed a cross algebra, that defines views such that there is no restriction that forces the view and the source data models to be the same. We then define update propagation algorithms that can propagate changes from source to target irrespective of the exact translation and the data models. We validate our ideas by applying them to translation and change propagation between the XML and relational data models

Model Driven Application and Database Co-Evolution

Katedra počítač

Combining SOA and BPM Technologies for Cross-System Process Automation

This paper summarizes the results of an industry case study that introduced a cross-system business process automation solution based on a combination of SOA and BPM standard technologies (i.e., BPMN, BPEL, WSDL). Besides discussing major weaknesses of the existing, custom-built, solution and comparing them against experiences with the developed prototype, the paper presents a course of action for transforming the current solution into the proposed solution. This includes a general approach, consisting of four distinct steps, as well as specific action items that are to be performed for every step. The discussion also covers language and tool support and challenges arising from the transformation

A theory and model for the evolution of software services

Software services are subject to constant change and variation. To control service development, a service developer needs to know why a change was made, what are its implications and whether the change is complete. Typically, service clients do not perceive the upgraded service immediately. As a consequence, service-based applications may fail on the service client side due to changes carried out during a provider service upgrade. In order to manage changes in a meaningful and effective manner service clients must therefore be considered when service changes are introduced at the service provider's side. Otherwise such changes will most certainly result in severe application disruption. Eliminating spurious results and inconsistencies that may occur due to uncontrolled changes is therefore a necessary condition for the ability of services to evolve gracefully, ensure service stability, and handle variability in their behavior. Towards this goal, this work presents a model and a theoretical framework for the compatible evolution of services based on well-founded theories and techniques from a number of disparate fields.

A theory and model for the evolution of software services.

Software services are subject to constant change and variation. To control service development, a service developer needs to know why a change was made, what are its implications and whether the change is complete. Typically, service clients do not perceive the upgraded service immediately. As a consequence, service-based applications may fail on the service client side due to changes carried out during a provider service upgrade. In order to manage changes in a meaningful and effective manner service clients must therefore be considered when service changes are introduced at the service provider's side. Otherwise such changes will most certainly result in severe application disruption. Eliminating spurious results and inconsistencies that may occur due to uncontrolled changes is therefore a necessary condition for the ability of services to evolve gracefully, ensure service stability, and handle variability in their behavior. Towards this goal, this work presents a model and a theoretical framework for the compatible evolution of services based on well-founded theories and techniques from a number of disparate fields.