Modular Synchronization in Multiversion Databases: Version Control and Concurrency Control

In this paper we propose a version control mechanism that enhances the modularity and extensibility of multiversion concurrency control algorithms. We decouple the multiversion algorithms into two components: version control and concurrency control. This permits modular development of multiversion protocols, and simplifies the task of proving the correctness of these protocols. An interesting feature of our framework is that the execution of read-only transactions becomes completely independent of the underlying concurrency control implementation. Also, algorithms with the version control mechanism have several advantages over most other multiversion algorithms

Distilling Quantum Entanglement via Mode-Matched Filtering

We propose a new avenue towards distillation of quantum entanglement that is implemented by directly passing the entangled qubits through a mode-matched filter. This approach can be applied to a common class of entanglement impurities appearing in photonic systems where the impurities inherently occupy different spatiotemporal modes than the entangled qubits. As a specific application, we show that our method can be used to significantly purify the telecom-band entanglement generated via the Kerr nonlinearity in single-mode fibers where a substantial amount of Raman-scattering noise is concomitantly produced.Comment: 6 pages, 2 figures, to appear in Phys. Rev.

Fault Coverage Requirement in Production Testing of LSI Circuits

A technique is described for evaluating the effectiveness of production tests for large scale integrated (LSI) circuit chips. It is based on a model for the distribution of faults on a chip. The model requires two parameters, the average number (n0) of faults on a faulty chip and the yield (y) of good chips. It is assumed that the yield either is known or can be calculated from the available formulas. The other parameter, n0, is determined from an experimental procedure. Once the model is fully characterized, it allows calculation of the field reject rate as a function of the fault coverage. The technique implicitly takes into account such variables as fault simulator characteristics, the feature size, and the manufacturing environment. An actual LSI circuit is used as an example