Control-flow mispredictions are a profound impediment to processor performance, because each misprediction introduces a pipeline bubble of many cycles’ duration. For example, the minimum bubble in the recently released Alpha 21264 is at least seven cycles, and often as much as twenty cycles. With such long penalties, even small misprediction rates harm performance substantially. Although a huge...

We give a new, topological proof that the weak Hanani-Tutte theorem is true on orientable surfaces and extend the result to nonorientable surfaces. That is, we show that if a graph G cannot be embedded on a surface S, then any drawing of G on S must contain two edges that cross an odd number of times. We apply the result and proof techniques to obtain new and old results about generalized thrac...

Reconciliation is the commonly used method for inferring the evolutionary scenario for a gene family. It consists in “embedding” an inferred gene tree into a known species tree, revealing the evolution of the gene family by duplications and losses. The main complaint about reconciliation is that the inferred evolutionary scenario is strongly dependant on the considered gene tree, as few misplac...

In this paper we discus the elimination of function and class clones from industrial object-oriented code. Clone removal can decrease code size and facilitate maintenance. We eliminate clones by reengineering scenarios that are based on automated restructuring tools. The paper presents examples of clones, reengineering scenarios, and restructuring tools. The usefulness of the approach is demons...

This paper concerns the barriers to interoperability that exist between the X.509 and EDIFACT Public Key Infrastructures (PKI), and proposes a method to overcome them. The solution lies in the DED-ICA 1 (Directory based EDI Certiicate Access and management) TELEM-ATIC Project, funded by the European Union. The main objective of this project is to deene and provide means to make these two infras...

Timed automata are among the most widely studied models for real-time systems. Silent transitions, i.e., "-transitions, have already been proposed in the original paper on timed automata by Alur and Dill [2]. In [7] it is shown that "-transitions can be removed, if they do not reset clocks; moreover "-transitions strictly increase the power of timed automata, if there is a self-loop containing ...

Suppose that the inverse image of the zero vector by a continuous map f : R → R has an isolated point P . The existence of a continuous map g which approximates f but is nonvanishing near P is equivalent to a topological property we call “locally inessential,” generalizing the notion of index zero for vector fields, the q = n case. For dimensions n, q where πn−1(Sq−1) is trivial, every isolated...

1 I n t r o d u c t i o n Computer designers and computer architects have been striving to improve uniprocessor performance since the invention of computers. The next step in this quest for higher performance is the exploitation of significant amounts of instruction-level parallelism. Therefore, superscalar and VLIW (very large instruction word) machines have been designed, which can execute se...

Cryptographic libraries that implement Transport Layer Security (TLS) have a responsibility to delete cryptographic keys once they’re no longer in use. Any key that’s left in memory can potentially be recovered through the actions of an attacker, up to and including the physical capture and forensic analysis of a device’s memory. This paper describes an analysis of the TLS library stack used in...