Saïd Tazi

Integration of business process modeling and Web services: a survey

A significant challenge in business process automation involves bridging the gap between business process representations and Web service technologies that implement business activities. We are interested in business process representations such as Business Process Modeling Notation (BPMN) and Event-Driven Process Chains (EPCs). Web service technologies include protocols such as Simple Object Access Protocol (SOAP), architectures such as REpresentational State Transfer (RESTful), or semantic description languages and formalisms such as Web Ontology Language for Services (OWL-S) and Web Service Modeling Ontology (WSMO). This paper reviews previous work on the integration of business process representations and Web service technologies. It provides a perspective on the field by summarizing, organizing, and classifying the proposed approaches. Consequently, this study has identified opportunities for future research in the field, including the need for a generic transformation approach among arbitrary models, the need to represent mappings in a formalized way, and the necessity of a common execution framework.

A model-driven adaptive approach for collaborative ubiquitous systems

Ubiquitous communicating systems have particular characteristics, such as their dynamic nature and the great number of users and heterogeneous devices involved. In our work, we focus on collaborative activities. For such activities, users are organized into groups and communicate in order to achieve a common goal. Therefore, the problem of designing and implementing collaborative applications on top of ubiquitous communicating systems is a complex task that requires adequate modeling. In our view, addressing this problem needs a model-driven approach in order to ensure the coherence and correctness of the built systems. In this paper, we propose a multi-level modeling approach for collaborative ubiquitous systems. Moreover, relevant abstraction levels are identified and means are provided for inter-level model transformation (refinement) and for adaptation to context changes (selection). This adaptation is guided by both high level requirements and low level constraints.

A Comprehensive Ontology-Based Approach for SLA Obligations Monitoring

Specifying clear quality of service (QoS) agreements between service providers and consumers is particularly important for the successful deployment of service-oriented architectures. The related challenges include correctly elaborating and monitoring QoS contracts (SLA: service level agreement) to detect and handle their violations. In this paper, first, we study and analyze existing SLA-related models. Then, we elaborate a complete, generic and semantically richer ontology-based model of SLA. We used the Semantic Web Rule Language (SWRL) to express SLA obligations in our model. This language facilitates the SLA monitoring process and the eventual action triggering in case of violations. We used this model to automatically generate semantic-enabled QoS obligations monitors. We have also developed a prototype to validate our model and our monitoring approach. Finally, we believe that this work is a step ahead to the total automation of the SLA management process.

What about collaboration in ubiquitous environments

Ubiquitous computing environments provide a wide range of new challenges and possibilities in Distributed Systems. Among these, collaborative activities involving several users present some complex issues. These activities are very dynamic and imply heterogeneous communications and devices, and therefore adaptive solutions are required. Moreover, context has to be taken into account in order to provide a satisfactory service. It is necessary to consider both high-level requirements and low-level constraints to adapt the system to context changes. This paper claims that collaborative applications for ubiquitous environments represent a very challenging and promising research field. It also proves the requirements of adaptability and context-awareness of such applications by exploring the state of the art in this field.

Supporting Collaborative Learning Activities with a Digital Library and Annotations

Digital Libraries (DLs) usually provide facilities for browsing and searching their collections, and can enhance noticeably learning activities. The integration of an annotation tool with a DL can foster knowledge exchange between instructors and learners. It is important that an annotation system for DLs should be easily integrated with existing DLs. This paper presents an annotation system, called DLNotes, which can be easily embedded in DLs in order to enable free-text and ontology-based annotations. DLNotes also supports supervised annotation activities and allows discussion threads to be associated with each annotation, what is particularly important for e-learning.

A semantic-driven auto-adaptive architecture for collaborative ubiquitous systems

Ubiquitous computing environments are complex systems containing a great amount of heterogeneous devices and services available to users. Both user needs and services offered to them evolve very fast. This evolution requires the adaptation of the software architectures that support user activities. Moreover, such adaptation must be based on application semantics in order to better respond to user needs in any situation. This paper presents a work in progress that aims to build an architecture enabling the development of adaptive collaborative applications in ubiquitous computing environments. An ontology model, containing generic collaboration knowledge as well as domain-specific knowledge, is proposed in order to enable architecture adaptation and to support spontaneous and implicit sessions inside groups of humans and devices.

Pruning Based Service Selection Approach Under QoS and Temporal Constraints

Dynamic selection of the best services to execute abstract tasks of business processes is very important. Indeed, it enables to cope with complex users requirements that require the collaboration of several more elementary services. However, with the increasing amount of candidate services of each business task that offer different QoS (Quality of Service) values, the selection of the optimal combination of services becomes a very hard task. This problem is more complex when dealing with temporal properties of business processes associated with time-dependent QoS parameters that can change according to the execution time. Unlike static QoS which have been deeply studied in the existing service selection approaches, time-dependent QoS are insufficiently taken into consideration. In this paper, we are interested in the problem of service selection to satisfy a given business process while considering temporal properties associated to time-dependent QoS. The selection approach that we propose relies on a new service pruning approach that is applied prior to our selection algorithm to reduce the number of candidate services while guaranteeing that the optimal solution still be found.

A context and application-aware framework for resource management in dynamic collaborative wireless M2M networks

Achieving end-to-end goals of Wireless Machine to Machine Networks (M2M) is a highly challenging task. These goals include guaranteeing connectivity and maximizing throughput while satisfying application layer Quality of Service (QoS) requirements. Moreover, the problem becomes more complicated in the context of emerging dynamic allocation of application layer software components. This paper presents a collaborative framework for communications in M2M wireless networks. This framework is composed of a context-aware and application-aware software platform and a reasoning machine for network management. The software platform uses multi-level adaptation mechanisms to support dynamic collaboration activities. The platform is also capable of installing the required software components on the appropriate nodes. On the other hand, the reasoning machine for network management is designed using the tool known as Weighted Cognitive Map (WCM). The inference properties of WCMs allow the system to self-organize while considering multiple objectives and constraints. Methods for achieving different objectives using WCMs are illustrated, as well as how system processes can operate coherently to achieve end-to-end goals. Computer simulations show that the system achieves excellent performance results in metrics of call dropping and blocking probabilities and achieving the required Quality of Service (QoS) parameters of the applications.

Time-Dependent QoS Aware Best Service Combination Selection

Service Oriented Architecture allows developing complex business applications from existing services. Given that many services are available with the same functionality and with different Quality of Service QoS attributes, one common challenge is to select the best service combination regarding users requirements. Existing solutions often consider static QoS values for candidate services. Nevertheless, in real world applications, QoS values can change during time. In addition, besides structural constraints, several QoS and temporal constraints can also be specified at the business level. Considering time-dependent QoS values associated with business level constraints makes the selection process a very complex and time consuming decision problem given the large number of service combinations to be compared. To deal with this issue, in this paper, the authors propose a novel service selection approach based on QoS and temporal pruning techniques to reduce the number of candidate services. The proposed approach allows pruning uninteresting services based on a set of local thresholds. These latter are measured using constraint optimization models while dealing with general flow structures including sequential, parallel, choice and loop patterns and different types of QoS and temporal constraints. Experimental studies show the benefits of the proposed approach in particular in terms of computational time.

Quality of Service Specifications: A Semantic Approach

In operations related to Quality of Service (QoS) management such as SLA negotiations, QoS-aware service invocations and so, it is necessary to specify the required or negotiated quality parameters. Currently, there are no standards to formally describe QoS specifications at the network service level. Several works propose a fixed list of QoS parameters at the network level (e.g., delay, jitter, packet loss). However, solutions offering an extensible list of QoS parameters to specify QoS are more appropriate to deal with the heterogeneity of applications and network technologies. This paper proposes an ontology as a formal and extensible way of specifying QoS and provide the mapping between parameters of different layers. Using our ontology, clients and providers can adopt different user-perceived, application or network QoS parameters and metrics during the service negotiation and invocation, and use ontology reasoning to compare different parameters. The usage of this ontology is illustrated during the establishment of a VoIP session, where a high level QoS specification in the application layer is mapped into a network layer Class of Service defined by the service provider.