A key challenge posed by the Next Generation Internet landscape is that modern service-based applications need to cope with open and continuously evolving environments and to operate under dynamic circumstances (e.g., changes in the users requirements, changes in the availability of resources). Indeed, dynamically discover, select and compose the appropriate services in such environment is a challenging task. Self-adaptation approaches represent effective instruments to tackle this issue, because they allow applications to adapt their behaviours based on their execution environment. Unfortunately, although existing approaches support run-time adaptation, they tend to foresee the adaptation requirements and related solutions at design-time, while working under a "closed-world" assumption. In this article our objective is that of providing a new way of approaching the design, operation and run-time adaptation of service-based applications, by considering the adaptivity as an intrinsic characteristic of applications and from the earliest stages of their development. We propose a novel design for adaptation approach implementing a complete lifecycle for the continuous development and deployment of service-based applications, by facilitating (i) the continuous integration of new services that can easily join the application, and (ii) the operation of applications under dynamic circumstances, to face the openness and dynamicity of the environment. The proposed approach has been implemented and evaluated in a real-world case study in the mobility domain. Experimental results demonstrate the effectiveness of our approach and its practical applicability.

中文翻译：

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基于服务的应用程序的动态适应：适应方法的设计

下一代Internet格局构成的主要挑战是，基于现代服务的应用程序需要应对开放和不断发展的环境，并需要在动态环境下运行（例如，用户需求的变化，资源可用性的变化）。实际上，在这样的环境中动态发现，选择和组合适当的服务是一项艰巨的任务。自适应方法是解决此问题的有效手段，因为它们允许应用程序根据其执行环境来适应其行为。不幸的是，尽管现有方法支持运行时适应，但它们在“封闭世界”假设下工作时，往往会在设计时预见适应要求和相关解决方案。在本文中，我们的目标是通过将适应性视为应用程序的固有特性并从其开发的早期阶段开始，就提供一种新方法来处理基于服务的应用程序的设计，操作和运行时适应。我们通过促进（i）可以轻松加入应用程序的新服务的持续集成，以及（ii）应用程序的运行，提出了一种新颖的适应性设计方法，该方法实现了用于基于服务的应用程序的持续开发和部署的完整生命周期。在动态环境下，要面对环境的开放性和动态性。所提出的方法已在移动领域的实际案例研究中得到实施和评估。