A central theme in distributed network algorithms concerns understanding and coping with the issue of locality. Despite considerable progress, research efforts in this direction have not yet resulted in a solid basis in the form of a fundamental computational complexity theory for locality. Inspired by sequential complexity theory, we focus on a complexity theory for distributed decision proble...

Developing a distributed debugger is much more complex than developing a sequential debugger. This added complexity is mainly due to the non-determinism of events that communication delays introduce into distributed systems. We explore the problems that one must address when designing a distributed program debugger and then describe our design and implementation of DPD (distributed program debu...

This paper describes our ongoing work towards the implementation of an online Web Service Composition system, based on the most prevalent Web Service standards and utilizing other open source projects as sub-elements. The system will treat non-determinism as an inherent characteristic of the problem and will tackle it by exploiting AI planning technology, specifically contingency planning. The ...

A key feature of synchronous languages is that they conciliate con-currency with determinism. This is achieved by detecting so-called causality errors BG92, HM95, STB95], which occur when the composition of deterministic processes is not deterministic. Although the existing synchronous languages only deal with deterministic programs, it is not a restriction of the approach. We show how a synchr...

There is increasing demand to extend Object Request Broker (ORB) middleware to support distributed applications with stringent real-time requirements. However, conventional ORB implementations, such as CORBA ORBs, exhibit substantial priority inversion and non-determinism, which makes them unsuitable for applications with deterministic real-time requirements. This paper provides two contributio...

The adoption of Description Logics for modeling real world domains within the Semantic Web is exponentially increased in the last years, also due to the availability of a large number of reasoning algorithms. Most of them exploit the tableau algorithm which has to manage non-determinism, a feature that is not easy to handle using procedural languages such as Java or C++. Reasoning on real world...

In this paper, we consider the problem of synthesizing low-complexity controllers for incrementally stable switched systems. For that purpose, we establish a new approximation result for the computation of symbolic models that are approximately bisimilar to a given switched system. The main advantage over existing results is that it allows us to design naturally quantized switching controllers ...

In this work, we introduce a profiling scheme for modern functional logic languages covering notions like laziness, sharing, and non-determinism. Firstly, we instrument a natural (big-step) semantics in order to associate a symbolic cost to each basic operation (e.g., variable updates, function unfoldings, case evaluations). While this cost semantics provides a formal basis to analyze the cost ...

We investigate the runtime verification problem of hyperproperties, such as non-interference and observational determinism, given as formulas of the temporal logic HyperLTL. HyperLTL extends lineartime temporal logic (LTL) with trace quantifiers and trace variables. We show that deciding whether a HyperLTL formula is monitorable is PSPACE-complete. For monitorable specifications, we present an ...

The non-determinism, complexity, and size of distributed software systems present signi cant di culties for designers and maintainers. Visualization can help alleviate these di culties through interactive exploratory tools that allow both novice and experienced users to investigate a distributed computation using a common tool set. Essential to the success of a visual exploration tool is the ab...