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An early warning system (EWS) is an integrated system that supports the detection, monitoring and alerting of emergency situations. A possible application of an EWS is in epidemiological surveillance, to detect infectious disease outbreaks in geographical areas. In this scenario, a challenge in the development and integration of applications on top of EWS is to achieve common understanding between epidemiologists and software developers, allowing the specification of rules resulted from epidemiological studies. To address this challenge this paper describes an ontology-based model-driven engineering (MDE) framework that relies on the Situation Modelling Language (SML), a knowledge specification technique for situation identification. Some requirements are realized by revisiting SML, which resulted in a complete redesign of its semantics, abstract and concrete syntaxes. The initial validation shows that our framework can accelerate the generation of high quality situation-aware applica tions, being suitable for other application scenarios.

Future disease outbreaks may spread faster and stronger than recent epidemics, such as Zika, Ebola and Influenza. The integration of multiple existing Early Warning Systems (EWS) is a requirement to support disease surveillance in combating infectious disease outbreaks. In this direction, numerous applications have been developed considering big data from diverse sources. However, big data potential can only be exploited if interoperability challenges are addressed. In this paper we discuss a semantic interoperability problem when using data exchanging standards for EWS integration. Particularly, we identify an issue regarding the distinction between the concepts of situation and event in the Emergency Data Exchange Language (EDXL), the OASIS set of standards for disaster management. To cope with interoperability issues we propose an ontology-driven situation-aware approach for the development and integration of EWS. The approach leverages on the OntoEmerge core ontology, in which we incorporate the clear distinction between the concepts of situation and event.

The notion of situation enables designers, maintainers, and users to abstract from lower-level entities and properties and to focus on the higher-level patterns that emerge in time. Situation management concerns a number of tasks including situation specification, situation detection (which may involve composite situation pattern recognition), and situation’s life cycle control. This chapter discusses how to approach situation management from a rule-based perspective. We present a rule-based situation management infrastructure to support the development of situation-aware applications and show its applicability to a scenario in the public health domain, concerning situations for detecting influenza epidemics.

This paper aims at demonstrating that the Model-Driven Architecture (MDA) approach to transformation is suitable to cope with the abstraction gap between the specification of application rules for context-aware applications and the implementation of these rules using rule engines. This paper reports on the transformation of Event-Condition-Action (ECA) rules onto rules that can be executed by the Jess rules engine. We have applied the MDA approach to define this transformation, by specifying it in terms of mappings between elements of the ECA Domain-specific Language (ECA-DL), which is the language we developed to represent ECA rules, and the Jess metamodel. The transformation was fully specified, implemented using the Atlas Transformation Language (ATL) and tested with a simple example.

Context-awareness has been investigated for almost a decade and is considered as a convenient and desirable feature in distributed mobile systems since it allows these systems to benefit from the changes in their users’ context to dynamically tailor services to their users’ current situation and needs. This chapter addresses the research results and challenges of designing a flexible infrastructure to support the development of mobile context-aware applications. We discuss relevant context-awareness concepts, define architectural patterns on context-awareness, present the design of a target infrastructure, and discuss some related research and research trends. The context-aware infrastructure described in this chapter follows the principles of service-oriented architectures in which the dynamic customization of context-aware mobile services is specified by means of application behavior rules that are interpreted and applied by the infrastructure at runtime.

Context-awareness has emerged as an important and desirable feature in ubiquitous applications. This feature deals with the ability of applications to utilize information about the user’s environment (context) in order to tailor services to the user’s current situation and needs. This thesis aims at providing an integrated solution for the development of context-aware systems. The main objective is to facilitate the development of context-aware applications, focusing on two aspects: on offering context modelling abstractions and on providing infrastructural support by means of a context handling platform. The context modelling abstractions provide application developers with proper conceptual foundations that can be extended and specialized with specific application requirements. The context handling platform allows application functionality to be delegated to the platform, which reduces application development effort, time and, therefore, costs. This allows application developers to focus on their core business, instead of being bothered with application realization details.

In this paper we extend the concept of management domains to a new concept called Context-Aware Management Domains (CAMDs). CAMDs enable context-aware management of policies allowing the grouping of entities based on context information. Since context is dynamic, so is the domain membership. As a consequence, the association of policies with the entities in the domain also becomes dynamic. In this paper we provide CAMD examples and an information model together with a discussion on our ongoing implementation for our target context-aware service platform.

Context awareness has emerged as an important element in distributed computing. It offers mechanisms allowing applications to be aware of their environment and enabling them to adjust their behavior to the current context. In order to keep track of the relevant context information, a flexible service mechanism should be available for the client applications. In this paper we present a service architecture to provide context- awareness capabilities to users and client applications. Moreover, the service is able to react depending on the user's preferences and context. The conditions for the reaction and the reaction itself are defined in rules the users submit to the service by means of a convenient rule language.

Context-aware applications use and manipulate context information to detect high-level situations, which are used to adapt application behavior. This paper discusses the specification of situations in context-aware applications and introduces a rule-based approach to detect situations. Situations are specified using a combination of UML class diagrams and OCL constraints. We support a wide range of situations, which can be composed of more elementary kinds of context. We discuss how to cope with distribution and to exploit it beneficially for context manipulation and situation detection. We employ a generic rule-based platform (DJess [2]) to support the derivation of situations in a distributed fashion.

Context-aware applications can sense and explore the users’ context in order to provide proper and useful services to these users. These applications can react intelligently upon changes in the user’s context, performing actions relevant to the user, the application itself, and the interaction between user and application. Context-aware reactive behaviors can be expressed by using rules written in a Domain-specific Language, coined ECA-DL, specially developed for context-aware applications. This paper proposes support for the development of a generic component capable of executing rules written using ECA-DL. This component executes these rules by using Jess, which is a well-known tool for developing rule-based systems.

In previous work, we have defined conceptual foundations that can be beneficially used in context modeling. These conceptual foundations include the separation of entity and context, and the characterization of context as either Intrinsic or Relational. This paper aims at extending this approach by introducing the ontological concept of Situation as means of composing the elements of our ontology (entities, intrinsic and relational contexts) to model particular states of affairs of interest. Our concepts have been inspired by and aligned with conceptual theories from the fields of philosophy and cognitive sciences.

Context-aware application behaviors can be described as logic rules following the Event-Control-Action (ECA) pattern. In this pattern, an Event models an occurrence of interest (e.g., a change in context); Control specifies a condition that must hold prior to the execution of the action; and an Action represents the invocation of arbitrary services. We have defined a Controlling service aiming at facilitating the dynamic configuration of ECA rule specifications by means of a mobile rule engine and a mechanism that distributes context reasoning activities to a network of context processing nodes. In this paper we present a novel context modeling approach that provides application developers and users with more appropriate means to define context information and ECA rules. Our approach makes use of ontologies to model context information and has been developed on top of web services technology.

Context-awareness has emerged as an important and desirable feature in distributed mobile systems, since it benefits from the changes in the user's context to dynamically tailor services to the user's current situation and needs. This chapter presents our efforts on designing a flexible infrastructure to support the development of mobile context-ware applications. We discuss relevant context-awareness concepts, define architectural patterns on context-awareness and present the design of the target infrastructure. Our approach towards this infrastructure includes the definition of a service-oriented architecture in which the dynamic custamization of services is specified by means of description rules at infrastructure runtime.

In this paper we aim at defining conceptual foundations for context-aware applications. We argue that the concepts of entity and context should be separated in conceptual models for context-aware applications. Further, we propose a novel approach that characterizes context as either intrinsic or relational. The concepts we propose in this paper have been inspired by and aligned with conceptual theories from the fields of philosophy and cognitive sciences. Since we concentrate on conceptual modeling, understandability and clarity are given precedence over properties such as efficiency and tractability.

Context-aware services platforms aim at supporting the handling of contextual information in order to provide better user-tailored services. This paper addresses our current efforts towards a configurable and extensible services platform for context-aware applications. It discusses the use of a language and ontologies to cope with configurability and extensibility aspects

Service discovery is a process of locating, or discovering, one or more documents, that describe a particular service. Most of the current service discovery approaches perform syntactic matching, that is, they retrieve services descriptions that contain particular keywords from the user’s query. This often leads to poor discovery results, because the keywords in the query can be semantically similar but syntactically different, or syntactically similar but semantically different from the terms in a service description. Another drawback of the existing service discovery mechanisms is that the query-service matching score is calculated taking into account only the keywords from the user’s query and the terms in the service descriptions. Thus, regardless of the context of the service user and the context of the services providers, the same list of results is returned in response to a particular query. This paper presents a novel approach for service discovery that uses ontologies to capture the semantics of the user’s query, of the services and of the contextual information that is considered relevant in the matching process.

Context-aware platforms aim at providing support to application designers to conceive their context-aware applications using services, mechanisms and interfaces that shield them from the complexity introduced by handling contextual information. This paper explores the essential requirements to be satisfied by context-aware service platforms and proposes a definition of a generic architecture supporting the execution of adaptive context-aware mobile applications. The WASP platform, a web services based context-aware service platform on top of 3G networks, is taken as a reference.

This paper discusses the suitability of using ontologies for modeling context-aware services platforms. It addresses the directions of research we are following in the WASP (Web Architectures for Services Platforms) project. For this purpose a simple scenario is considered.

Architectural patterns have been proposed in many domains as means of capturing recurring design problems that arise in specific design situations. In this paper, we present three architectural patterns that can be applied beneficially in the development of context-aware services platforms. These patterns present solutions for recurring problems associated with managing context information and proactively reacting upon context changes. We demonstrate the benefits of applying these patterns by discussing the AWARENESS architecture.