Amirreza Tahamtan

Temporal Conformance of Federated Choreographies

Web service composition is a new way for implementing business processes. In particular, a choreography supports modeling and enactment of interorganizational business processes consisting of autonomous organizations. Temporal constraints are important quality criteria. We propose a technique for modeling temporal constraints in choreographies and orchestrations, checking whether the orchestrations satisfy the temporal constraints of a choreography and compute internal deadlines for the activities in an interorganizational workflow.

A Cloud Repository and Discovery Framework Based on a Unified Business and Cloud Service Ontology

Cloud computing introduces a fundamental shift in service delivery. A market registry, flexibility, exchangeability and integration of services are important issues for its success. In this work we introduce a unified Cloud and business service ontology with querying capabilities. Our framework addresses two aspects: on the one hand it gives answer to leading question how we can structure the term Cloud computing (as a question of basic research) and how we can enable a matching between offered Cloud services and demand. It closes the gap how we can summarize and describe Cloud services in a standardized way. On the other hand, it particularly addresses the demand for flexibility and exchangeability by the Cloud Computing paradigm and can serves as a repository of services.

Temporal Consistency of View Based Interorganizational Workflows

Interorganizational workflows are a major step in automating B2B electronic commerce and to support collaborations of organizations on the technical level. Process views are an important conceptual modelling approach for interorganizational workflows as they allow interaction and communication while internal and private parts of the process can be hidden. However, it is essential to guarantee that an interorganizational workflow is free of conflicts and the overall quality assurances of the whole workflow can be achieved. This paper proposes an approach for checking temporal consistency of interorganizational workflows crossing boundaries of organizations.

Conformance Test of Federated Choreographies

Web Services technology is constantly gaining importance for automation of business processes. A major contribution of this technology is its integration capability, i.e. compositions allowing several autonomous but cooperating web services to implement a business process going beyond the boundaries of a single organization. Federated choreographies provide a framework for modular modeling complex collections of choreographies and orchestrations. In this paper we present a conformance test to check the structural conformance of the choreographies and orchestration of the proposed model in order to hold the model structurally consistent. We can formally check whether an orchestration realizing (one part of) a choreography, resp. two related choreographies fit together.

View driven inter-organisational workflows

We propose a layered architecture for choreographies and orchestrations of web services. The proposed architecture uses the concept of process views. The distributed nature of the model and the concept of views improve the privacy of business partners but do not limit their interaction capabilities, an essential feature in B2B and inter-organisational applications. Our approach enables description of business processes in different levels of detail with a uniform modelling language and is fully distributed.

View-based interorganizational workflows

We propose a new architecture for modeling and enacting of interorganizational business processes which captures both control flow and data flow aspects of web service orchestrations and choreographies. A major modeling concepts is a view mechanism to balance the problems of openness, privacy and coupling in cross-organization interactions. The view concept cares both for process abstraction and for data transformation between business partners. To cope with interoperability problems that arise from different data formats and internal schemas used by different choreography participants we support transformation of XML-based data types through our views. The approach allows a to enact interorganizational business processes in a fully distributed way without the need for any central coordinator.

Probabilistic Time Management of Choreographies

Temporal conformance of web service compositions guarantees the timely execution of service calls, decreases follow-up costs and increases QoS by avoiding deadline violations. Since it is impossible to make certain statements about the execution intervals of upcoming web service executions - mainly due to varying activity durations and hard-to-predict branching behavior - we propose a probabilistic approach to model flow structures and temporal information, and show how to validate the temporal conformance of web service compositions.

A SOM-based technique for a user-centric content extraction and classification of web 2.0 with a special consideration of security aspects

Web 2.0 is much more than adding a nice facade to old web applications rather it is a new way of thinking about software architecture of Rich Internet Applications (RIA). In comparison to traditional web applications, the application logic of modern Web 2.0 applications tends to push the interactive user interface tasks to the client side. The client components on the other hand negotiate with remote services that deal with user events. The user should be assisted in different scenarios in order to use the existing platforms, share the resources with other users and improve his security. In this paper we present a user-centered content extraction and classification method based on self-organizing maps (SOM) as well as a prototype for provided content on Web 2.0. The extracted and classified data serves as a basis for above mentioned scenarios.

Self-monitoring in social networks

Web 2.0 has changed the technological landscape of the internet computing world today. The shift from traditional web which is also known as Web 1.0 is forced by the growing need for more efficient information sharing, collaboration, and business processes. The disclosure of personal/organisational information in Web 2.0 via social networks, digital contributions and data feeds has created new security and privacy challenges. Designing transparent, usable systems in support of personal privacy, security, and trust, requires advanced knowledge retrieval techniques that can support information sharing processes by applying appropriate policies. This paper proposes a Web 2.0 analysis methodology that provides reusable foundation components for information extraction, analysis and visualisation. These components can be used by the same method can be also used by individuals to make a self-test of their Web 2.0 contributions and find out what inferences will be derived from their web presence.

View Driven Federation of Choreographies

We propose a layered architecture for choreographies and orchestrations of web services. The proposed architecture uses the concept of process views. The distributed nature of the model and the concept of views improve the privacy of business partners but do not limit their interaction capabilities, an essential feature in B2B and interorganizational applications. Our approach enables description of business processes in different levels of detail with a uniform modeling language and is fully distributed.