In recent years, new classes of highly dynamic, complex systems are gaining momentum. These classes include, but are not limited to IoT, smart cities, cyber-physical systems and sensor networks. These systems are characterized by the need to express behaviors driven by external and/or internal changes, i.e. they are reactive and context-aware. A desirable design feature of these systems is the ability of adapting their behavior to environment changes. In this paper, we propose an approach to support adaptive, reactive systems based on semantic runtime representations of their context, enabling the selection of equivalent behaviors, i.e. behaviors that have the same effect on the environment. The context representation and the related knowledge are managed by an engine designed according to a reference architecture and programmable through a declarative definition of sensors and actuators. The knowledge base of sensors and actuators (hosted by an RDF triplestore) is bound to the real world by grounding semantic elements to physical devices via REST APIs. The proposed architecture along with the defined ontology tries to address the main problems of dynamically re-configurable systems by exploiting a declarative, queryable approach to enable runtime reconfiguration with the help of (a) semantics to support discovery in heterogeneous environment, (b) composition logic to define alternative behaviors for variation points, (c) bi-causal connection life-cycle to avoid dangling links with the external environment. The proposal is validated in a case study aimed at designing an edge node for smart buildings dedicated to cultural heritage preservation.

中文翻译：

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自适应反应系统的语义驱动编程

近年来，新型高度动态、复杂的系统正在获得动力。这些类别包括但不限于物联网、智慧城市、网络物理系统和传感器网络。这些系统的特点是需要表达由外部和/或内部变化驱动的行为，即它们是反应性的和上下文感知的。这些系统的一个理想设计特点是能够使其行为适应环境变化。在本文中，我们提出了一种基于上下文的语义运行时表示来支持自适应、反应式系统的方法，从而能够选择等效行为，即对环境具有相同影响的行为。上下文表示和相关知识由根据参考架构设计的引擎管理，并通过传感器和执行器的声明性定义进行编程。传感器和执行器的知识库（由 RDF 三元存储托管）通过 REST API 将语义元素与物理设备绑定到现实世界。所提出的体系结构以及定义的本体试图通过利用声明性、可查询的方法来解决动态可重新配置系统的主要问题，从而借助（a）支持异构环境中发现的语义来启用运行时重新配置，（b）组合定义变化点的替代行为的逻辑，（c）双因果连接生命周期，以避免与外部环境的悬空链接。