Abstract. Given the different perspectives from which a complex software system has to be analyzed, the multiplicity of formalisms is unavoidable. This poses two important technical challenges: how to rigorously meet the need to interrelate formalisms, and how to reduce the duplication of effort in tool and specification building across formalisms. These challenges could be answered by adequate formal meta-tools that, when given the specification of a formal inference system, generate an efficient inference engine, and when given a specification of two formalisms and a translation, generate an actual translator between them. Similarly, module composition operations that are logic-independent, but that at present require costly implementation efforts for each formalism, could be provided for logics in general by module algebra generator meta-tools. The foundations of meta-tools of this kind can be based on a metatheory of general logics. Their actual design and implementation can be based on appropriate logical frameworks having efficient implementations. This paper explains how the reflective logical framework of rewriting logic can be used, in conjunction with an efficient reflective implementation such as the Maude language, to design formal meta-tools such as those described above. The feasibility of these ideas and techniques has been demonstrated by a number of substantial experiments in which new formal tools and new translations between formalisms, efficient enough to be used in practice, have been generated.

In this paper, we address the role of middleware in enabling robust and resilient cyber-physical systems (CPSs) of the future. In particular, we will focus on how adaptation services can be used to improve dependability in instrumented cyber-physical systems based on the principles of "computational reflection." CPS environments incorporate a variety of sensing and actuation devices in a distributed architecture; such a deployment is used to create a digital representation of the evolving physical world and its processes for use by a broad range of applications. CPS applications, in particular, mission critical tasks, must execute dependably despite disruptions caused by failures and limitations in sensing, communications, and computation. This paper discusses a range of applications, their reliability needs, and potential dependability holes that can cause performance degradation and application failures. In particular, we distinguish between the notion of infrastructure and information dependability and illustrate the need to formally model and reason about a range of CPS applications and their de

Abstract-We argue for a policy-based approach to increase spectrum availability. To this extend, we briefly summarize a new language for expressing policies that allow opportunistic spectrum access. A Policy Reasoner that reasons about these policies can be used with cognitive radios to guarantee policyspecified behaviors while allowing spectrum sharing. We present our policy reasoner design and we evaluated the reasoner in a demonstration. We describe the policies used in that demonstration and the results of the evaluation.