Djamel Belaïd

An autonomic approach to manage elasticity of business processes in the Cloud

Cloud Computing is gaining more and more importance in the Information Technologies (IT) scope. One of the major assets of this paradigm is its economic model based on pay-as-you-go model. Cloud Computing gets more attention from IT users when it fits their required QoS and reduces their expenses. This task cannot be done without increasing the autonomy of the provisioned Cloud resources. In this paper, we propose a holistic approach that allows to dynamically adding autonomic management facilities to Cloud resources even if they were designed without these facilities. Based on the Open Cloud Computing Interface (OCCI) standard, we propose a generic model that allows describing the needed resources to render autonomic a given Cloud resource independently of the service level (Infrastructure, Platform or Software). Herein, we define new OCCI Resources, Links and Mixins that allow provisioning autonomic Cloud Resources. In order to illustrate our approach, we propose a use case that specializes our autonomic infrastructure to ensure the elasticity of Service-based Business Processes (SBPs). The elasticity approach that we are using is based on a formal model that features duplication/consolidation mechanisms and a generic Controller that defines and evaluates elasticity strategies. To validate our proposal, we present an end to end scenario of provisioning an elastic SBP on a public PaaS. Evaluation of our approach on a realistic situation shows its efficiency. We propose an autonomic management model for Cloud resources.We extend Open Cloud Computing Interface to describe our autonomic model.We illustrate our autonomic model with an approach for Business Processes elasticity.We propose a formal approach for Business Processes elasticity.We show the efficiency of our approach on a realistic Cloud environment.

User Preferences-Based Automatic Device Selection for Multimedia User Tasks in Pervasive Environments

Multimedia task composition involves automatic matching and selection of multimedia services across various devices in the pervasive environment. During the composition process, various QoS attributes are considered for selection of the service components implementing those services. However, the existing approaches about multimedia service composition do not consider users perspective about utilizing services and devices. The automatic selection of service components keeps the user out of the whole process. The result is that the end-user may not always be satisfied with the final set of automatically chosen components and devices. In this paper, we propose a solution for multimedia task composition based on user preferences vis-a-vis device capabilities. User tasks are defined in terms of abstract services, which may also specify their requirements. Both of these criteria are considered simultaneously and a quantitative model for selection of service components and devices is presented.

A model for resource specification in mobile services

The proliferation of small devices and the increase in number of services created by various vendors for such devices have made SOA a primary choice for mobile software developers. However, due to software and hardware platforms heterogeneity, it is not always possible to use the write-once, use-everywhere approach. The main problem comes due to the varying capability of mobile devices and the unavailability of means to know resource requirements of mobile services. We believe that there is a need to be able to specify resource requirements so that mobile application developers could explicitly enumerate their requirements, when it comes to interoperability with other services. Towards this objective, we consider the requirements of mobile services, identified from CC/PP, a generic model of resource specification on mobile devices. We then extend the existing CC/PP model and integrate it with the SCA model for SOA. Our approach does not violate any of the CC/PP or SCA specification, while remaining neutral to the underlying technologies and platforms. An important aspect of our approach is that resources can be specified abstractly as well as concretely.

Dynamic User Task Composition Based on User Preferences

As the number of devices in a pervasive environment is increased, the number of components available on the network also grows rapidly. In such cases, it is possible to compose various applications through a combination of different sets of components. Considering the multifaceted problem of having varying device capabilities supporting a different set of protocols, and each device hosting a number of components providing the same functionality, it becomes very difficult to choose a particular device hosting a required component which can be the best-fit for the user. This becomes practically impossible when the required components are distributed across various devices in the networked environment. We propose a solution for dynamic user task composition considering user preferences, device capabilities, and heterogeneity of communication protocols. With our proposed approach, a user task can be instantiated in different environments using a different set of devices and components, depending upon their capabilities and user preferences. We propose mechanisms for modeling device capabilities and user preferences and for modeling the user task as a graph. We then propose algorithms for selection of devices based on user preferences and task requirements. Since the underlying network is also modeled as a graph, we describe an algorithm for mapping of services in the user task on to the components distributed across devices in the pervasive environment. We also give an overview of our initial implementation and some results of our evaluations.

Toward an Integrated Ontology for Web Services

The lack of semantics in Web Services Description Language (WSDL) prevents automatic discovery and hence automatic invocation and composition. In our work, we are interested in extending existing approaches for the description of Semantic Web Services. Previously, we have extended the W3C recommendation on Semantics for Web Services (SAWSDL) and have proposed the use of two types of ontologies: a Technical Ontology type containing concepts defining semantics of services, their QoS,etc. and a Domain Ontology type containing the concepts defining the semantics of the business domain. The aim of this paper is to present Yet Another Semantic Annotation for WSDL (YASA4WSDL) and define a technical service ontology for YASA4WSDL. This ontology integrates useful concepts of WSDL meta-model, and OWL-S and WSMO ontologies. The integration of these ontologies is based on different matching techniques according to an ontology mapping process. The resulting ontology covers specific Web services semantic concepts.

Session Mobility of Multimedia Applications in Home Networks Using UPnP

With the increasing demand for multimedia contents and with the increased usage of small hand-held devices, a user in a home network has a number of devices at hand which may offer similar multimedia services but with varying capabilities. The user may choose one device for using a particular multimedia service at one time, and change to another device at another time. The user may, however, continue using the same service and maintain his previous session on the new device without restarting a new session. In this paper, we describe how UPnP can be used for transferring a multimedia session from a device to another in a home network. The procedure for transfer of session is based on the UPnP audio video architecture. We also describe our prototype implementation.

A quantitative model for user preferences based on qualitative specifications

With an increasing number of devices having varying capabilities and with different types of network access mechanisms, an ordinary user will consider various tradeoffs for selecting one particular device over the other for execution of his task in an ad hoc environment. We propose a model for specifying user preferences so that the selection of the best device for the user is automated. Users specify their preferences and constraints qualitatively, which are then mapped on to a quantitative utility model. Preferences can be specified both for users liking and dislike. We analyze the theory of TCP-nets as a formal model for representing and reasoning with qualitative preferences, and show how it can be used to create a quantitative preference model. Using an example scenario, the application of our model is shown and its utility against simple additive models is discussed.

A Policy-Based Approach for Resource Specification in Small Devices

A distributed application can be implemented as components, which might be available on a single host or distributed across various hosts. However, in a pervasive environment, such applications cannot be described statically in terms of the required components. This is because in such environments, the device participation is dynamic and the components described in application may not be available at the time of execution of the application. We believe that the description of the application must be generated dynamically at the time of its execution, in terms of the components available at that time. We present an approach in which an application is described in terms of abstract services, which are resolved into concrete components at runtime.When mapping services to components, their resource requirements are matched apart from their functional interfaces. Resources are also specified at both abstract and concrete levels. Only those components are selected whose interfaces and concrete resource requirements match with the abstract service interfaces and abstract resource requirements. The application composition is specified in SCA and CC/PP is used for resource specification using SCA policies.

Persuasive Healthcare Self-Management in Intelligent Environments

An important feature of the intelligent environments is that they monitor user activities and help them in making decisions based on their progress in activities. Many such environments have been designed previously for healthcare management. However, more than often users are reluctant to consider the feedback from the environment alone. So we consider experts recommendations and social network of the user as additional entities that form part of the intelligent environment. However, unlike traditional approaches, they influence the user indirectly through various persuasion techniques. The main idea is to change the behavior of the user for improving healthcare management. In this article we identify salient features of our framework for healthcare self-management in intelligent environments that combines ubiquitous and social computing as persuasion media. The framework enables social interactions between the patients, doctors, and other users in their online social community through a web portal as well as through their smart phones. Both users behavior and preferences are taken into account to help them in adopting healthy behavior. This is done by using different persuasion strategies created on the basis of the users behavior model. As a case study we consider diabetes self-management in this article.

Monitoring and Reconfiguration for OCCI Resources

Monitoring and reconfiguration are critical issues in Cloud environments. Monitoring allows to detect violations and specific events, while reconfiguration allows to activate corrective mechanisms or runtime modifications. In this paper we propose an extension for Open Cloud Computing Interface (OCCI) to enable monitoring and reconfiguration. The extension describes the needed elements to manage (i.e., to monitor and reconfigure) cloud resources on demand. The definition entails the introduction of new OCCI Resources, Links and Mixins. We define on the one hand new types needed to monitor metrics based on a previously established SLA. On the other hand we define the needed types to reconfigure our managed resources when needed. The newly added elements are OCCI entities defined as generic Kinds, that are specialized using OCCI Mixins. Using these elements, the user is provided with a monitoring and reconfiguration infrastructure on demand. We propose herein, a real use case based on HTTP rendering showing how to establish and link the described elements of the infrastructure.