ArchOptions: A Real Options-Based Model for Predicting the Stability of Software Architectures

Architectural stability refers to the extent an architecture is flexible to endure evolutionary changes in stakeholders\' requirements and the environment. We assume that the primary goal of software architecture is to guide the system\'s evolution. We contribute to a novel model that exploits options theory to predict architectural stability. The model is predictive: it provides \"insights\" on the evolution of the software system based on valuing the extent an architecture can endure a set of likely evolutionary changes. The model builds on Black and Scholes financial options theory (Noble Prize wining) to value such extent. We show how we have derived the model: the analogy and assumptions made to reach the model, its formulation, and possible interpretations. We refer to this model as ArchOptions

Business objects: the next step in component technology?

Component technology seems to be a promising approach towards more efficient software development by enabling application construction through “plug and play”. However, the middleware supporting this approach is still complicated to use and distracts the attention of the component developer from the application domain to technical implementation issues. Business objects are intended to hide the complexities of middleware approaches and provide an easy to use environment for application developers. We conceptualize business object approaches by presenting a common model and survey some major players in the marketplace. We conclude by identifying implications of business objects on information systems engineering.

Generating a contract checker for an SLA language

SLAng is a language for expressing Service LevelAgreements (SLAs) under development as part of the Europeanproject TAPAS. It is defined using a meta-model, an instance ofthe Meta-Object Facility (MOF) model, in which the relationshipbetween the syntax of the language and its domain of applicationis explicitly represented, and the violation semantics ofthe language defined using Object Constraint Language (OCL)constraints. The concrete syntax of the language is the XMLMeta-data Interchange (XMI) mapping of the syntactic part ofthe meta-model. In this paper we describe how the Java MetadataInterface (JMI) mapping can be applied to the meta-modelof the language to generate interfaces and classes to create andquery SLAs and relevant service monitoring data in memory;and how an OCL interpreter can be applied to check violationconstraints over this data, resulting in the implementation of acontract checker that is highly likely to respect the semantics ofthe language

SLAng: A language for defining service level agreements

Application or web services are increasingly being used across organisational boundaries. Moreover, new services are being introduced at the network and storage level. Languages to specify interfaces for such services have been researched and transferred into industrial practice. We investigate end-to-end quality of service (QoS) and highlight that QoS provision has multiple facets and requires complex agreements between network services, storage services and middleware services. We introduce SLAng, a language for defining Service Level Agreements (SLAs) that accommodates these needs. We illustrate how SLAng is used to specify QoS in a case study that uses a web services specification to support the processing of images across multiple domains and we evaluate our language based on it

Precise service level agreements

SLAng is an XML language for defining service level agreements, the part of a contract between the client and provider of an Internet service that describes the quality attributes that the service is required to possess. We define the semantics of SLAng precisely by modelling the syntax of the language in UML, then embedding the language model in an environmental model that describes the structure and behaviour of services. The presence of SLAng elements imposes behavioural constraints on service elements, and the precise definition of these constraints using OCL constitutes the semantic description of the language. We use the semantics to define a notion of SLA compatibility, and an extension to UML that enables the modelling of service situations as a precursor to analysis, implementation and provisioning activities

Controversies Regarding Memorials to Romani Victims of National Socialist Violence in Burgenland (Austria)

In 1984, on the initiative of associations for the victims of National Socialism, the federal state of Burgenland dedicated a memorial in Lackenbach to the Romani victims of National Socialist violence. It was erected in the vicinity of a former National Socialist “Gypsy detention camp”, the largest internment, forced labour, and transit camp of its kind in Austria. Following the suggestions of the Kulturverein österreichischer Roma (Cultural Association of Austrian Roma), an annual commemoration ceremony has been held at the site since 1990. In 1989, a memorial to all local victims of National Socialism was inaugurated in Oberwart. In recent years, one could almost speak of a “remembrance boom” in regard to Romani victims of National Socialist violence in Austria.In 1984, on the initiative of associations for the victims of National Socialism, the federal state of Burgenland dedicated a memorial in Lackenbach to the Romani victims of National Socialist violence. It was erected in the vicinity of a former National Socialist “Gypsy detention camp”, the largest internment, forced labour, and transit camp of its kind in Austria. Following the suggestions of the Kulturverein österreichischer Roma (Cultural Association of Austrian Roma), an annual commemoration ceremony has been held at the site since 1990. In 1989, a memorial to all local victims of National Socialism was inaugurated in Oberwart. In recent years, one could almost speak of a “remembrance boom” in regard to Romani victims of National Socialist violence in Austria

Markup meets middleware

We describe a distributed system architecture that supports the integration of different front-office trading systems with middle and back-office systems, each of which have been procured from different vendors. The architecture uses a judicious combination of object-oriented middleware and markup languages. In this combination an object request broker implements reliable trade data transport. Markup languages, particularly XML, are used to address data integration problems. We show that the strengths of middleware and markup languages are complementary and discuss the benefits of deploying middleware and markup languages in a synergistic manner

Condor services for the Global Grid:interoperability between Condor and OGSA

In order for existing grid middleware to remain viable it is important to investigate their potentialfor integration with emerging grid standards and architectural schemes. The Open Grid ServicesArchitecture (OGSA), developed by the Globus Alliance and based on standard XML-based webservices technology, was the first attempt to identify the architectural components required tomigrate towards standardized global grid service delivery. This paper presents an investigation intothe integration of Condor, a widely adopted and sophisticated high-throughput computing softwarepackage, and OGSA; with the aim of bringing Condor in line with advances in Grid computing andprovide the Grid community with a mature suite of high-throughput computing job and resourcemanagement services. This report identifies mappings between elements of the OGSA and Condorinfrastructures, potential areas of conflict, and defines a set of complementary architectural optionsby which individual Condor services can be exposed as OGSA Grid services, in order to achieve aseamless integration of Condor resources in a standardized grid environment