Abstract. Previous shape analysis algorithms use a memory model where the heap is composed of discrete nodes that can be accessed only via access paths built from variables and field names, an assumption that is violated by pointer arithmetic. In this paper we show how this assumption can

for such data structures becomes significantly more challenging in the presence of low-level pointer manipulation that is prevalent in systems software. In this paper, we give a novel formalization of the reachability predicate in the presence of internal pointers and pointer arithmetic. We have designed

Abstract. We introduce a prefetching technique that is able to accurately prefetch complex pointer-based data structures. Compile time shape analysis is used to determine the set of possible future objects accessed by a program. We use the reachability graph generated during the shape analysis

Vast majority of wireless appliances used in household, industry and medical field share the ISM frequency band. These devices need to coexist and thus are challenged to tolerate their mutual interference. One way of dealing with this is by using frequency hopping; where the device changes its radio channel periodically. Consequently, communications will not suffer from the same interference each time; instead, it should be fairer and more stable. This thesis investigates the aforementioned problem in the field of low power wireless sensor networks and Internet of Things where Contiki OS is used. We introduce a low-power pseudo-random frequency-hopping MAC protocol which is specifically characterized as a duty cycled asynchronous sender-initiated LPL style protocol. We illustrate two flavors of the protocol; one that does not use any dedicated channel and another which allows dedicated broadcast channels that can implement frequency-hopping as well. We implement

Effective support for custom proof automation is essential for large-scale interactive proof develop-ment. However, existing languages for automation via tactics either (a) provide no way to specify the behavior of tactics within the base logic of the accompanying theorem prover, or (b) rely on advanced type-theoretic machinery that is not easily integrated into established theorem provers. We present Mtac, a lightweight but powerful extension to Coq that supports dependently typed tactic programming. Mtac tactics have access to all the features of ordinary Coq programming, as well as a new set of typed tactical primitives. We avoid the need to touch the trusted kernel type-checker of Coq by encapsulating uses of these new tactical primitives in a monad, and instrumenting Coq so that it executes monadic tactics during type inference. 1

I am grateful to Luc Segoufin who kindly accepted me to be his PhD student. He introduced me to the problem of query enumeration and encouraged me to look for the answers to all the questions that emerged during our collaboration. He was a truly great advisor, always supportive and available for discussions and advice. I would like to thank Arnaud Durand and Patrice Ossona de Mendez for accepting to review this thesis and for their constructive comments on the earlier versions of this manuscript. Many thanks to Nicole Bidoit and Victor Vianu for accepting to be in my jury. Special thanks go to my Parents, who directed me to follow the scientific path and where fully supportive at all times. Thanks to all the members of LSV – it was a pleasure working with You. I would like to thank the awesome people whom I have been working with in the same office on the 4th floor. Without all the nice riddles and the magnificent French lessons my time there wouldn’t be as chouette as it was. Big thanks go to my son Boris, who was kind enough to sleep through the whole nights, allowing his dad to actually write the thesis down.

Abstract The field of astronomy education is rapidly growing beyond merely sharing effective activities or curriculum ideas. This paper categorizes and summarizes the literature in astronomy education research and contains more than 100 references to articles, books, and Web-based materials

mcmxciv This thesis deals with combinatorics in connection with Coxeter groups, finitely generated but not necessarily finite. The representation theory of groups as nonsingular matrices over a field is of immense theoretical importance, but also basic for computational group theory, where the group elements are data structures in a computer. Matrices are unnecessarily large structures, and part of this thesis is concerned with small and efficient representations of a large class of Coxeter groups (including most Coxeter groups that anyone ever payed any attention to.) The main contents of the thesis can be summarized as follows. • We prove that for all Coxeter graphs constructed from an n-path of unlabelled edges by adding a new labelled edge and a new vertex (sometimes two new edges and vertices), there is a permutational representation of the corresponding group. Group elements correspond to integer n-sequences and the nodes in the path generate all n! permutations. The extra node has a more complicated action, adding a certain quantity to some of the numbers.

I discuss Julian Barbour's Machian theories of dynamics, and his proposal that a Machian perspective enables one to solve the problem of time in quantum ge-ometrodynamics (by saying that there is no time!). I concentrate on his recent

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