Proceedings of the Tenth International Conference on Enterprise Information Systems, 2008
Service provisioning is a challenging research area for the design and implementation of autonomi... more Service provisioning is a challenging research area for the design and implementation of autonomic serviceoriented software systems. It includes automated QoS management for such systems and their applications. Monitoring, Diagnosis and Repair are three key features of QoS management. This work presents a selfhealing Web service-based framework that manages QoS degradation at runtime. Our approach is based on proxies. Proxies act on meta-level communications and extend the HTTP envelope of the exchanged messages with QoS-related parameter values. QoS Data are filtered over time and analysed using statistical functions and the Hidden Markov Model. Detected QoS degradations are handled with proxies. We experienced our framework using an orchestrated electronic shop application (FoodShop).
2018 IEEE 27th International Conference on Enabling Technologies: Infrastructure for Collaborative Enterprises (WETICE), 2018
The goal of this track is to bring together researchers and practitioners both from the Academia ... more The goal of this track is to bring together researchers and practitioners both from the Academia and from the Industry working in the areas of the adaptation and reconfiguration of distributed systems. Different investigation topics are involved, such as: CBSE, Web service, cloud applications, mobile applications, Functional and Non-Functional requirements (QoS, performance, resilience), monitoring, diagnosis, decision and execution of adaptation and reconfiguration. Different research areas are covered: concepts, methods, techniques, and tools to design, develop, deploy and manage adaptive and reconfigurable software systems.
The Internet 2 deployment introduces new capabilities, such as multi-party collaboration, high-sc... more The Internet 2 deployment introduces new capabilities, such as multi-party collaboration, high-scale multimedia assembly and multicast communication. For this reason, the research concerning security is facing new challenges. One such challenge is to create secure multi-session frameworks to ensure the confidentiality of exchanged information. In a multi-session environment, several users are joined at two or more work sessions simultaneously. The confidentiality in these environments can be achieved using cryptographic methods. Unfortunately, the key management, necessary for such environments, creates two main problems: a high complexity in key distribution and a high storage cost. In this paper, we propose an efficient multi-session key management mechanism for dynamic multimedia group communication. Our solution proposes a functional architecture that exploits the overlapping of the user sessions to reduce the redundancy in key distribution. The proposed key management makes use...
Proceedings of the 15th International Conference on Enterprise Information Systems, 2013
Although design patterns have become increasingly popular, most of them are presented in an infor... more Although design patterns have become increasingly popular, most of them are presented in an informal way. Patterns, proposed by the SOA design pattern community, are described with a proprietary informal notation, which can raise ambiguity and may lead to their incorrect usage. Modeling SOA design patterns with a standard formal notation avoids misunderstanding by software architects and helps endow design methods. In this paper, we present an approach that aims, first, to model message-oriented SOA design patterns with the SoaML language, and second to transform them to Event-B specifications. These two steps are performed before undertaking the effective coding of a design pattern providing correct by construction pattern-based software architectures. Our approach is enhanced with a tool supporting it. Specification results are imported under the Rodin platform which we use to prove model consistency.
Sensing coverage is one the most fundamental research issues in wireless sensor networks. It refl... more Sensing coverage is one the most fundamental research issues in wireless sensor networks. It reflects how well a sensor network is able to monitor or track a field of interest. So far, several sensing coverage protocols have been proposed. Throughout the diversity of research works in this topic, major interests focused purely on the coverage problem under the restrictive assumption that each deployed node is equipped with a GPS receiver that provides it with its precise location. However, in some applications, GPS service may be unavailable, non-practical and very expensive. Confronted to this constraint, different GPS-less localization algorithms for wireless sensor networks have been introduced. Such algorithms enable sensor nodes to estimate their position with some degree of precision. In this paper, we tackle the problem of maintaining coverage from the perspective of a GPS-less localization. We present the design and analysis of a novel integrated framework guaranteeing both sensing coverage and GPS-less localization. In sharp contrast to several existing approaches that address the two problems in isolation, we integrate the wellknown coverage configuration protocol CCP with the GPS-less localization algorithm AT-Dist. Extensive simulations results show the efficiency of the proposed unified framework in providing guaranteed coverage and localization while considerably reducing the energy consumption. We also discuss the potential security threats in the framework and propose the use of a secure solution to deal with them.
Proceedings of the 28th Annual ACM Symposium on Applied Computing - SAC '13, 2013
Autonomic systems are known by their abilities to manage and reconfigure themselves according to ... more Autonomic systems are known by their abilities to manage and reconfigure themselves according to the context changes that can include the evolution of functional and/or nonfunctional requirements, without human intervention. The design and the management of such complex systems manually is a hard task since both functional and non-functional requirements should be taken into consideration. In this paper, we propose a model driven methodology which enables the dynamic reconfiguration by generating autonomic architectures from high level descriptions of functional requirements. Based on transformation and refinement rules, this methodology automates the incorporation of non-functional requirements to the initial architecture. Our work follows the Model Driven Architecture (MDA) to cover the different abstraction levels.
16th IEEE International Workshops on Enabling Technologies: Infrastructure for Collaborative Enterprises (WETICE 2007), 2007
This paper addresses QoS management for self-healing Web services. The objective is to provide a ... more This paper addresses QoS management for self-healing Web services. The objective is to provide a healing framework based on service monitoring and architectural-level repair actions. We address these topics in the context of the European project WS-DIAMOND. We implemented and assessed a connector-based healing layer capable of intercepting, analyzing and enhancing SOAP traffic and message contents with QoS data. Our framework supports Service Monitoring and dynamic run-time reconfiguration based on reflective programming.
2009 IEEE Symposium on Computers and Communications, 2009
Service provisioning is a challenging research area for the design and implementation of autonomi... more Service provisioning is a challenging research area for the design and implementation of autonomic serviceoriented software systems. It includes automated QoS management for such systems and their applications. Monitoring and Measurement are two key features of QoS management. They are addressed in this paper as elements of a main step in provisioning of self-healing web services. In a previous work [1], we defined and implemented a generic architecture applicable for different services within different business activities. Our approach is based on meta-level communications defined as extensions of the SOAP envelope of the exchanged messages, and implemented within handlers provided by existing web service containers. Using the web services technology, we implemented a complete prototype of a service-oriented Conference Management System (CMS). We experienced our monitoring and measurement architecture using the implemented application and assessed successfully the scalability of our approach under the French grid5000. In this paper, experimental results are analyzed and concluding remarks are given.
Autonomic systems are known by their ability to manage and reconfigure themselves in reaction to ... more Autonomic systems are known by their ability to manage and reconfigure themselves in reaction to context changes without human intervention. The manual design and management of such complex systems is an error-prone task where both functional and non-functional requirements can be disturbed. In this paper, we provide a correct-by-design approach that allows a given abstract architectural description to be refined into autonomic architecture models that are close to implementations. The challenge is to get a system architecture that includes the necessary components for monitoring the non-functional parameters (e.g. quality of service) and reacting to any degradation by performing runtime reconfigurations. For solving such a problem, we provide an automated approach where an architecture is modelled as a conceptual graph with different levels of abstractions. Nodes represent software components or services or connectors and vertices represent communication or interaction links. To endow a given architecture with such properties, we define graph transformation rules to formally refine a given abstract representation into a specific model allowing the easy implementation of the autonomic schema. Such a refined schema includes the autonomic control loop components namely Monitoring, Analysis, Planning, and Execution (MAPE). We apply our approach to the "Campus-Wide Smart Metering" use-case providing a service-oriented style connecting Machine-to-Machine devices.
The Wireless Sensor Networks (WSNs) deployment introduces many issues and challenges mainly in te... more The Wireless Sensor Networks (WSNs) deployment introduces many issues and challenges mainly in terms of energy independence. In this context, we adopted a self-adaptation strategy composed of four steps (Monitor, Analyze, Plan and Execute) to manage Quality of Service (QoS) [1]. This paper focuses on the first step which consists in monitoring and sending QoS values such as the value of power remaining in the battery of each sensor. We notice that the transmission process is very expensive in terms of energy and reduces the battery lifetime. In this work, we propose a probabilistic approach that estimates a part of these QoS monitoring values and therefore economizes their transmission energy and extends the sensor battery life. Our approach is based on the hidden Markov chain and the fuzzy logic and composed of two steps: (i) learning which allows apprehending the WSNs behavior and (ii) predicting which estimates QoS monitoring values. A WSN application deployed in a datacenter is studied as an illustration. The carried out experiments over AZEM WSN simulator show its feasibility and efficiency.
2012 IEEE 21st International Workshop on Enabling Technologies: Infrastructure for Collaborative Enterprises, 2012
This paper aims at designing of adaptive framework for supporting collaborative work of different... more This paper aims at designing of adaptive framework for supporting collaborative work of different actors in public safety and disaster recovery missions. In such scenarios, firemen and robots interact to each other to reach a common goal; firemen team is equipped with smart devices and robots team is supplied with communication technologies, and should carry on specific tasks. Here, reliable connection is mandatory to ensure the interaction between actors. But wireless access network and communication resources are vulnerable in the event of a sudden unexpected change in the environment. Also, the continuous change in the mission requirements such as inclusion/exclusion of new actor, changing the actor's priority and the limitations of smart devices need to be monitored. To perform dynamically in such case, the presented framework is based on a generic multi-level modeling approach that ensures adaptation handled by semantic modeling. Automated selfconfiguration is driven by rule-based reconfiguration policies through ontology.
Adaptation of deployment is required for maintaining the Quality of Service (QoS) in Service Orie... more Adaptation of deployment is required for maintaining the Quality of Service (QoS) in Service Oriented Architectures (SOA). Dynamic reconfiguration of SOA is proposed here to cope with adaptation in reaction to or in prediction of QoS degradation. Handling such an issue needs to detect and to identify the deficiency source, and to reconfigure the architecture implementing service composition. System reconfiguration constitutes a complex activity acting on distributed software entities, and requires to be implemented by correct model- ...
2008 First International Conference on the Applications of Digital Information and Web Technologies (ICADIWT), 2008
Monitoring and analysis of QoS are crucial steps for the provisioning of self-healing web service... more Monitoring and analysis of QoS are crucial steps for the provisioning of self-healing web services and for managing web service-based distributed interactive applications. Dealing with these issues becomes even more challenging when applications are dynamically built by composition of distributed services involving different service providers. In this case, assuming access to the internal logic and its implementation within the composed web services is not realistic. In this paper, we propose an architectural framework for monitoring and analysis of QoS driven by models for QoS analysis. This framework has been implemented and experimented for the web service technology within the European WS-DIAMOND 1 project. We consider the general context where only SOAP messages between web services are monitored. The main novelty of our approach is, on the one hand, to provide a generic application-independent framework. On the other hand, we provide models allowing QoS deficiencies to be detected and considered as an indicator of the health degradation of the monitored web services.
Journal of Network and Computer Applications, 2014
Achieving end-to-end goals of Wireless Machine to Machine Networks (M2M) is a highly challenging ... more 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.
Eighth International Workshop on Principles of Software Evolution (IWPSE'05)
This paper provides a graphical simulator that enables to apprehend the dynamic of components-bas... more This paper provides a graphical simulator that enables to apprehend the dynamic of components-based software architectures based on their formal specification. The simulator initially accepts (as an input) an already validated Z specification using the Z/EVES tool. Then, it generates graphical entities, according to the UML notation, representing software's components and their connectors. Thereafter, the user may generate architecture instances by adding components and connections between them. Architecture instances can be updated by destroying components/connections or by modifying their interconnections. The user actions are checked through the formal specification of the architectural style.
2008 19th International Conference on Database and Expert Systems Applications, 2008
Failures during web service execution may depend on a wide variety of causes, such as network fau... more Failures during web service execution may depend on a wide variety of causes, such as network faults, server crashes, or application-related errors, such as unavailability of a requested web service, errors in the orchestration of choreography of applications, missing data or parameters in an execution flow, or low Quality of Service (QoS). In this paper, we propose a healing architecture able to handle web service faults in a selfhealing way, discussing infrastructural faults and web service and Web application faults. The self-healing architecture manages repair actions, such as substitution of a faulty service or duplication of overloaded services. Implemented prototypes involving QoS in coordinated web services are illustrated and discussed. 1
The Wireless Sensor Networks (WSNs) deployment introduces many issues and challenges mainly in te... more The Wireless Sensor Networks (WSNs) deployment introduces many issues and challenges mainly in terms of energy independence. In this context, we adopted the IBM control loop which is composed of four steps (Monitor, Analyze, Plan and Execute) to manage Quality of Service (QoS) 1. This paper focuses on the first step which consists in monitoring and sending periodically QoS values such as the value of power remaining in the battery of each sensor. We notice that the transmission process is very costly in terms of energy and reduces the battery lifetime. In this work, we propose a probabilistic approach that estimates a part of these QoS monitoring values and therefore economizes their transmission energy and extends the sensor battery lifetime. Our approach is based on the hidden Markov chain and the fuzzy logic. It is composed of two steps: (i) learning which allows apprehending the WSNs behavior and (ii) prediction which estimates QoS monitoring values. A WSN application deployed in a datacenter is studied as an illustration. The carried out experiments over AZEM 1 WSN simulator show that the gain varies from 25% to 75% of the battery energy.
Proceedings of the Tenth International Conference on Enterprise Information Systems, 2008
Service provisioning is a challenging research area for the design and implementation of autonomi... more Service provisioning is a challenging research area for the design and implementation of autonomic serviceoriented software systems. It includes automated QoS management for such systems and their applications. Monitoring, Diagnosis and Repair are three key features of QoS management. This work presents a selfhealing Web service-based framework that manages QoS degradation at runtime. Our approach is based on proxies. Proxies act on meta-level communications and extend the HTTP envelope of the exchanged messages with QoS-related parameter values. QoS Data are filtered over time and analysed using statistical functions and the Hidden Markov Model. Detected QoS degradations are handled with proxies. We experienced our framework using an orchestrated electronic shop application (FoodShop).
2018 IEEE 27th International Conference on Enabling Technologies: Infrastructure for Collaborative Enterprises (WETICE), 2018
The goal of this track is to bring together researchers and practitioners both from the Academia ... more The goal of this track is to bring together researchers and practitioners both from the Academia and from the Industry working in the areas of the adaptation and reconfiguration of distributed systems. Different investigation topics are involved, such as: CBSE, Web service, cloud applications, mobile applications, Functional and Non-Functional requirements (QoS, performance, resilience), monitoring, diagnosis, decision and execution of adaptation and reconfiguration. Different research areas are covered: concepts, methods, techniques, and tools to design, develop, deploy and manage adaptive and reconfigurable software systems.
The Internet 2 deployment introduces new capabilities, such as multi-party collaboration, high-sc... more The Internet 2 deployment introduces new capabilities, such as multi-party collaboration, high-scale multimedia assembly and multicast communication. For this reason, the research concerning security is facing new challenges. One such challenge is to create secure multi-session frameworks to ensure the confidentiality of exchanged information. In a multi-session environment, several users are joined at two or more work sessions simultaneously. The confidentiality in these environments can be achieved using cryptographic methods. Unfortunately, the key management, necessary for such environments, creates two main problems: a high complexity in key distribution and a high storage cost. In this paper, we propose an efficient multi-session key management mechanism for dynamic multimedia group communication. Our solution proposes a functional architecture that exploits the overlapping of the user sessions to reduce the redundancy in key distribution. The proposed key management makes use...
Proceedings of the 15th International Conference on Enterprise Information Systems, 2013
Although design patterns have become increasingly popular, most of them are presented in an infor... more Although design patterns have become increasingly popular, most of them are presented in an informal way. Patterns, proposed by the SOA design pattern community, are described with a proprietary informal notation, which can raise ambiguity and may lead to their incorrect usage. Modeling SOA design patterns with a standard formal notation avoids misunderstanding by software architects and helps endow design methods. In this paper, we present an approach that aims, first, to model message-oriented SOA design patterns with the SoaML language, and second to transform them to Event-B specifications. These two steps are performed before undertaking the effective coding of a design pattern providing correct by construction pattern-based software architectures. Our approach is enhanced with a tool supporting it. Specification results are imported under the Rodin platform which we use to prove model consistency.
Sensing coverage is one the most fundamental research issues in wireless sensor networks. It refl... more Sensing coverage is one the most fundamental research issues in wireless sensor networks. It reflects how well a sensor network is able to monitor or track a field of interest. So far, several sensing coverage protocols have been proposed. Throughout the diversity of research works in this topic, major interests focused purely on the coverage problem under the restrictive assumption that each deployed node is equipped with a GPS receiver that provides it with its precise location. However, in some applications, GPS service may be unavailable, non-practical and very expensive. Confronted to this constraint, different GPS-less localization algorithms for wireless sensor networks have been introduced. Such algorithms enable sensor nodes to estimate their position with some degree of precision. In this paper, we tackle the problem of maintaining coverage from the perspective of a GPS-less localization. We present the design and analysis of a novel integrated framework guaranteeing both sensing coverage and GPS-less localization. In sharp contrast to several existing approaches that address the two problems in isolation, we integrate the wellknown coverage configuration protocol CCP with the GPS-less localization algorithm AT-Dist. Extensive simulations results show the efficiency of the proposed unified framework in providing guaranteed coverage and localization while considerably reducing the energy consumption. We also discuss the potential security threats in the framework and propose the use of a secure solution to deal with them.
Proceedings of the 28th Annual ACM Symposium on Applied Computing - SAC '13, 2013
Autonomic systems are known by their abilities to manage and reconfigure themselves according to ... more Autonomic systems are known by their abilities to manage and reconfigure themselves according to the context changes that can include the evolution of functional and/or nonfunctional requirements, without human intervention. The design and the management of such complex systems manually is a hard task since both functional and non-functional requirements should be taken into consideration. In this paper, we propose a model driven methodology which enables the dynamic reconfiguration by generating autonomic architectures from high level descriptions of functional requirements. Based on transformation and refinement rules, this methodology automates the incorporation of non-functional requirements to the initial architecture. Our work follows the Model Driven Architecture (MDA) to cover the different abstraction levels.
16th IEEE International Workshops on Enabling Technologies: Infrastructure for Collaborative Enterprises (WETICE 2007), 2007
This paper addresses QoS management for self-healing Web services. The objective is to provide a ... more This paper addresses QoS management for self-healing Web services. The objective is to provide a healing framework based on service monitoring and architectural-level repair actions. We address these topics in the context of the European project WS-DIAMOND. We implemented and assessed a connector-based healing layer capable of intercepting, analyzing and enhancing SOAP traffic and message contents with QoS data. Our framework supports Service Monitoring and dynamic run-time reconfiguration based on reflective programming.
2009 IEEE Symposium on Computers and Communications, 2009
Service provisioning is a challenging research area for the design and implementation of autonomi... more Service provisioning is a challenging research area for the design and implementation of autonomic serviceoriented software systems. It includes automated QoS management for such systems and their applications. Monitoring and Measurement are two key features of QoS management. They are addressed in this paper as elements of a main step in provisioning of self-healing web services. In a previous work [1], we defined and implemented a generic architecture applicable for different services within different business activities. Our approach is based on meta-level communications defined as extensions of the SOAP envelope of the exchanged messages, and implemented within handlers provided by existing web service containers. Using the web services technology, we implemented a complete prototype of a service-oriented Conference Management System (CMS). We experienced our monitoring and measurement architecture using the implemented application and assessed successfully the scalability of our approach under the French grid5000. In this paper, experimental results are analyzed and concluding remarks are given.
Autonomic systems are known by their ability to manage and reconfigure themselves in reaction to ... more Autonomic systems are known by their ability to manage and reconfigure themselves in reaction to context changes without human intervention. The manual design and management of such complex systems is an error-prone task where both functional and non-functional requirements can be disturbed. In this paper, we provide a correct-by-design approach that allows a given abstract architectural description to be refined into autonomic architecture models that are close to implementations. The challenge is to get a system architecture that includes the necessary components for monitoring the non-functional parameters (e.g. quality of service) and reacting to any degradation by performing runtime reconfigurations. For solving such a problem, we provide an automated approach where an architecture is modelled as a conceptual graph with different levels of abstractions. Nodes represent software components or services or connectors and vertices represent communication or interaction links. To endow a given architecture with such properties, we define graph transformation rules to formally refine a given abstract representation into a specific model allowing the easy implementation of the autonomic schema. Such a refined schema includes the autonomic control loop components namely Monitoring, Analysis, Planning, and Execution (MAPE). We apply our approach to the "Campus-Wide Smart Metering" use-case providing a service-oriented style connecting Machine-to-Machine devices.
The Wireless Sensor Networks (WSNs) deployment introduces many issues and challenges mainly in te... more The Wireless Sensor Networks (WSNs) deployment introduces many issues and challenges mainly in terms of energy independence. In this context, we adopted a self-adaptation strategy composed of four steps (Monitor, Analyze, Plan and Execute) to manage Quality of Service (QoS) [1]. This paper focuses on the first step which consists in monitoring and sending QoS values such as the value of power remaining in the battery of each sensor. We notice that the transmission process is very expensive in terms of energy and reduces the battery lifetime. In this work, we propose a probabilistic approach that estimates a part of these QoS monitoring values and therefore economizes their transmission energy and extends the sensor battery life. Our approach is based on the hidden Markov chain and the fuzzy logic and composed of two steps: (i) learning which allows apprehending the WSNs behavior and (ii) predicting which estimates QoS monitoring values. A WSN application deployed in a datacenter is studied as an illustration. The carried out experiments over AZEM WSN simulator show its feasibility and efficiency.
2012 IEEE 21st International Workshop on Enabling Technologies: Infrastructure for Collaborative Enterprises, 2012
This paper aims at designing of adaptive framework for supporting collaborative work of different... more This paper aims at designing of adaptive framework for supporting collaborative work of different actors in public safety and disaster recovery missions. In such scenarios, firemen and robots interact to each other to reach a common goal; firemen team is equipped with smart devices and robots team is supplied with communication technologies, and should carry on specific tasks. Here, reliable connection is mandatory to ensure the interaction between actors. But wireless access network and communication resources are vulnerable in the event of a sudden unexpected change in the environment. Also, the continuous change in the mission requirements such as inclusion/exclusion of new actor, changing the actor's priority and the limitations of smart devices need to be monitored. To perform dynamically in such case, the presented framework is based on a generic multi-level modeling approach that ensures adaptation handled by semantic modeling. Automated selfconfiguration is driven by rule-based reconfiguration policies through ontology.
Adaptation of deployment is required for maintaining the Quality of Service (QoS) in Service Orie... more Adaptation of deployment is required for maintaining the Quality of Service (QoS) in Service Oriented Architectures (SOA). Dynamic reconfiguration of SOA is proposed here to cope with adaptation in reaction to or in prediction of QoS degradation. Handling such an issue needs to detect and to identify the deficiency source, and to reconfigure the architecture implementing service composition. System reconfiguration constitutes a complex activity acting on distributed software entities, and requires to be implemented by correct model- ...
2008 First International Conference on the Applications of Digital Information and Web Technologies (ICADIWT), 2008
Monitoring and analysis of QoS are crucial steps for the provisioning of self-healing web service... more Monitoring and analysis of QoS are crucial steps for the provisioning of self-healing web services and for managing web service-based distributed interactive applications. Dealing with these issues becomes even more challenging when applications are dynamically built by composition of distributed services involving different service providers. In this case, assuming access to the internal logic and its implementation within the composed web services is not realistic. In this paper, we propose an architectural framework for monitoring and analysis of QoS driven by models for QoS analysis. This framework has been implemented and experimented for the web service technology within the European WS-DIAMOND 1 project. We consider the general context where only SOAP messages between web services are monitored. The main novelty of our approach is, on the one hand, to provide a generic application-independent framework. On the other hand, we provide models allowing QoS deficiencies to be detected and considered as an indicator of the health degradation of the monitored web services.
Journal of Network and Computer Applications, 2014
Achieving end-to-end goals of Wireless Machine to Machine Networks (M2M) is a highly challenging ... more 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.
Eighth International Workshop on Principles of Software Evolution (IWPSE'05)
This paper provides a graphical simulator that enables to apprehend the dynamic of components-bas... more This paper provides a graphical simulator that enables to apprehend the dynamic of components-based software architectures based on their formal specification. The simulator initially accepts (as an input) an already validated Z specification using the Z/EVES tool. Then, it generates graphical entities, according to the UML notation, representing software's components and their connectors. Thereafter, the user may generate architecture instances by adding components and connections between them. Architecture instances can be updated by destroying components/connections or by modifying their interconnections. The user actions are checked through the formal specification of the architectural style.
2008 19th International Conference on Database and Expert Systems Applications, 2008
Failures during web service execution may depend on a wide variety of causes, such as network fau... more Failures during web service execution may depend on a wide variety of causes, such as network faults, server crashes, or application-related errors, such as unavailability of a requested web service, errors in the orchestration of choreography of applications, missing data or parameters in an execution flow, or low Quality of Service (QoS). In this paper, we propose a healing architecture able to handle web service faults in a selfhealing way, discussing infrastructural faults and web service and Web application faults. The self-healing architecture manages repair actions, such as substitution of a faulty service or duplication of overloaded services. Implemented prototypes involving QoS in coordinated web services are illustrated and discussed. 1
The Wireless Sensor Networks (WSNs) deployment introduces many issues and challenges mainly in te... more The Wireless Sensor Networks (WSNs) deployment introduces many issues and challenges mainly in terms of energy independence. In this context, we adopted the IBM control loop which is composed of four steps (Monitor, Analyze, Plan and Execute) to manage Quality of Service (QoS) 1. This paper focuses on the first step which consists in monitoring and sending periodically QoS values such as the value of power remaining in the battery of each sensor. We notice that the transmission process is very costly in terms of energy and reduces the battery lifetime. In this work, we propose a probabilistic approach that estimates a part of these QoS monitoring values and therefore economizes their transmission energy and extends the sensor battery lifetime. Our approach is based on the hidden Markov chain and the fuzzy logic. It is composed of two steps: (i) learning which allows apprehending the WSNs behavior and (ii) prediction which estimates QoS monitoring values. A WSN application deployed in a datacenter is studied as an illustration. The carried out experiments over AZEM 1 WSN simulator show that the gain varies from 25% to 75% of the battery energy.
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Papers by Khalil Drira