The DigiHome Service-Oriented Platform

International audienceNowadays, the computational devices are everywhere. In malls, offices, streets, cars, and even homes, we can find devices providing and consuming functionality to improve the user satisfaction. These devices include sensors that provide information about the environment state (e.g., temperature, occupancy, light levels), service providers (e.g., Internet TVs, GPS), smartphones (that contain user preferences), and actuators that act on the environment (e.g., closing the blinds, activating the alarm, changing the temperature). Although these devices exhibit communication capabilities, their integration into a larger monitoring system remains a challenging task, partly because of the strong heterogeneity of technologies and protocols. Therefore, in this article, we focus on home environments and propose a middleware solution, called DigiHome, that applies the Service Component Architecture (SCA) component model to integrate data and events generated by heterogeneous devices in this kind of environments. DigiHome exploits the SCA extensibility to incorporate the REpresentational State Transfer (REST) architectural style and, in this way, leverages on the integration of multiscale systems-of-systems (from wireless sensor networks to the Internet). Additionally, the platform applies Complex Event Processing technology that detects application-specific situations. We claim that the modularization of concerns fostered by DigiHome and materialized in a service-oriented architecture, makes it easier to incorporate new services and devices in smart home environments. The benefits of the DigiHome platform are demonstrated on smart home scenarios covering home automation, emergency detection, and energy saving situations

The DigiHome Service-Oriented Platform

International audienceNowadays, the computational devices are everywhere. In malls, offices, streets, cars, and even homes, we can find devices providing and consuming functionality to improve the user satisfaction. These devices include sensors that provide information about the environment state (e.g., temperature, occupancy, light levels), service providers (e.g., Internet TVs, GPS), smartphones (that contain user preferences), and actuators that act on the environment (e.g., closing the blinds, activating the alarm, changing the temperature). Although these devices exhibit communication capabilities, their integration into a larger monitoring system remains a challenging task, partly because of the strong heterogeneity of technologies and protocols. Therefore, in this article, we focus on home environments and propose a middleware solution, called DigiHome, that applies the Service Component Architecture (SCA) component model to integrate data and events generated by heterogeneous devices in this kind of environments. DigiHome exploits the SCA extensibility to incorporate the REpresentational State Transfer (REST) architectural style and, in this way, leverages on the integration of multiscale systems-of-systems (from wireless sensor networks to the Internet). Additionally, the platform applies Complex Event Processing technology that detects application-specific situations. We claim that the modularization of concerns fostered by DigiHome and materialized in a service-oriented architecture, makes it easier to incorporate new services and devices in smart home environments. The benefits of the DigiHome platform are demonstrated on smart home scenarios covering home automation, emergency detection, and energy saving situations

RESTful Service Development for Resource-constrained Environments

International audienceThe use of resource-constrained devices, such as smartphones, PDAs, Tablet PCs, and Wireless Sensor Networks (WSNs) is spreading rapidly in the business community and our daily life. Accessing services from such devices is very common in ubiquitous environments, but mechanisms to describe, implement and distribute these services remain a major challenge. Web services have been characterized as an efficient and widely-adopted approach to overcome heterogeneity, while this technology is still heavyweight for resource-constrained devices. The emergence of REST architectural style as a lightweight and simple interaction model has encouraged researchers to study the feasibility of exploiting REST principles to design and integrate services hosted on devices with limited capabilities. In this chapter, we discuss the state-of-the-art in applying REST concepts to develop Web services for WSNs and smartphones as two representative resource-constrained platforms, and then we provide a comprehensive survey of existing solutions in this area. In this context, we report on the DIGIHOME platform, a home monitoring middleware solution, which enables efficient service integration in ubiquitous environments using REST architectural style. In particular, we target our reference platforms for homemonitoring systems, namelyWSNs and smartphones, and report our experiments in applying the concept of Component-Based Software Engineering (CBSE) in order to provide resource-efficient RESTful distribution of Web services for those platforms

Integration of Heterogeneous Context Resources in Ubiquitous Environments

International audienceUbiquitous environments provide families of context-aware applications that are capable of exploiting the user mobility as well as the device variability. Typically, these applications retrieve context information from local and remote providers and react accordingly to the detected variations. However, this must be done by considering the heterogeneity of devices and protocols found in ubiquitous environments. Unfortunately, although the context integration represents a keystone of context-aware systems, existing approaches in the literature fail to integrate the diversity of context sources in a standard and flexible way. Therefore, in this paper, we overcome this challenge by introducing resource-oriented bindings into the SCA (Service Component Architecture) model. This new kind of bindings follows the REpresentational State Transfer (REST) principles and leverages the provision of context as RESTful resources. A smart home scenario that highlights challenges in terms of integration in ubiquitous environments motivates the use of our approach

State of runtime adaptation in service-oriented systems:what, where, when, how and right

Software as a Service reflects a ‘service-oriented’ approach to software development that is based on the notion of composing applications by discovering and invoking network-available services to accomplish some task. However, as more business organisations adopt service-oriented solutions and the demands on them grow, the problem of ensuring that the software systems can adapt fast and effectively to changing business needs, changes in their runtime environment and failures in provided services has become an increasingly important research problem. Dynamic adaptation has been proposed as a way to address the problem. However, for adaptation to be effective several other factors need to be considered. This study identifies the key factors that influence runtime adaptation in service-oriented systems (SOSs) and examines how well they are addressed in 29 adaptation approaches intended to support SOSs

A model-driven approach for facilitating user-friendly design of complex event patterns

Complex Event Processing (CEP) is an emerging technology which allows us to efficiently process and correlate huge amounts of data in order to discover relevant or critical situations of interest (complex events) for a specific domain. This technology requires domain experts to define complex event patterns, where the conditions to be detected are specified by means of event processing languages. However, these experts face the handicap of defining such patterns with editors which are not user-friendly enough. To solve this problem, a model-driven approach for facilitating user-friendly design of complex event patterns is proposed and developed in this paper. Besides, the proposal has been applied to different domains and several event processing languages have been compared. As a result, we can affirm that the presented approach is independent both of the domain where CEP technology has to be applied to and of the concrete event processing language required for defining event patterns

Integration of Heterogeneous Context Resources in Ubiquitous Environments

International audienceUbiquitous environments provide families of context-aware applications that are capable of exploiting the user mobility as well as the device variability. Typically, these applications retrieve context information from local and remote providers and react accordingly to the detected variations. However, this must be done by considering the heterogeneity of devices and protocols found in ubiquitous environments. Unfortunately, although the context integration represents a keystone of context-aware systems, existing approaches in the literature fail to integrate the diversity of context sources in a standard and flexible way. Therefore, in this paper, we overcome this challenge by introducing resource-oriented bindings into the SCA (Service Component Architecture) model. This new kind of bindings follows the REpresentational State Transfer (REST) principles and leverages the provision of context as RESTful resources. A smart home scenario that highlights challenges in terms of integration in ubiquitous environments motivates the use of our approach

RESTful Discovery and Eventing for Service Provisioning in Assisted Living Environments

Service provisioning in assisted living environments faces distinct challenges due to the heterogeneity of networks, access technology, and sensing/actuation devices in such an environment. Existing solutions, such as SOAP-based web services, can interconnect heterogeneous devices and services, and can be published, discovered and invoked dynamically. However, it is considered heavier than what is required in the smart environment-like context and hence suffers from performance degradation. Alternatively, REpresentational State Transfer (REST) has gained much attention from the community and is considered as a lighter and cleaner technology compared to the SOAP-based web services. Since it is simple to publish and use a RESTful web service, more and more service providers are moving toward REST-based solutions, which promote a resource-centric conceptualization as opposed to a service-centric conceptualization. Despite such benefits of REST, the dynamic discovery and eventing of RESTful services are yet considered a major hurdle to utilization of the full potential of REST-based approaches. In this paper, we address this issue, by providing a RESTful discovery and eventing specification and demonstrate it in an assisted living healthcare scenario. We envisage that through this approach, the service provisioning in ambient assisted living or other smart environment settings will be more efficient, timely, and less resource-intensive.The authors extend their appreciation to the Deanship of Scientific Research at King Saud University for funding this work through the research group project No. RGP-VPP-049

ModeL4CEP: Graphical domain-specific modeling languages for CEP domains and event patterns

Complex event processing (CEP) is a cutting-edge technology that allows the analysis and correlation of large volumes of data with the aim of detecting complex and meaningful events through the use of event patterns, as well as permitting the inference of valuable knowledge for end users. Despite the great advantages that CEP can bring to expert or intelligent business systems, it poses a substantial challenge to their users, who are business experts but do not have the necessary knowledge and experience using this technology. The main problem these users have to face is precisely hand-writing the code for event pattern definition, which requires them to implement the conditions to be met to detect relevant situations for the domain in question by using a particular event processing language (EPL). In order to respond to this need, in this paper we propose both a graphical domain-specific modeling language (DSML) for facilitating CEP domain definitions by domain experts, and a graphical DSML for event pattern definition by non-technological users. The proposed languages provide high expressiveness and flexibility and are independent of event patterns and actions’ implementation code. This way, domain experts can define the relevant event types and patterns within their business domain, without having to be experts on EPL programming, nor on other complicated computer science technological issues, beyond an understandable and intuitive graphical definition. Furthermore, with these DSMLs, users will also be able to define the actions to be automatically taken once a pattern is detected in the system. Further benefits of these DSMLs are evaluated and discussed in depth in this paper

MEdit4CEP: A model-driven solution for real-time decision making in SOA 2.0

Organizations all around the world need to manage huge amounts of data from heterogeneous sources every day in order to conduct decision making processes. This requires them to infer what the value of such data is for the business in question through data analysis as well as acting promptly for critical or relevant situations. Complex Event Processing (CEP) is a technology that helps tackle this issue by detecting event patterns in real time. However, this technology forces domain experts to define these patterns indicating such situations and the appropriate actions to be executed in their information systems, generally based on Service-Oriented Architectures (SOAs). In particular, these users face the incommodity of implementing these patterns manually or by using editors which are not user-friendly enough. To deal with this problem, a model-driven solution for real-time decision making in event-driven SOAs is proposed and conducted in this paper. This approach allows the integration of CEP with this architecture type as well as defining CEP domain and event pattern through a graphical and intuitive editor, which also permits automatic code generation. Moreover, the solution is evaluated and its benefits are discussed. As a result, we can assert this is a novel solution for bringing CEP technology closer to any user, positively impacting on business decision making processes