I recently visited the Soviet Union. I was there for only one week, as a tourist: time to get only a very limited and superficial impression of life there. Nevertheless, it was a sobering and thought-provoking experience. For even such a brief visit forces one to confront the problems raised by the evidently unideal character of the Soviet Union and other ̀ actually existing' socialist societies...

Public blockchains are becoming a ubiquitous network service. However, it's hard to make consensus-breaking changes to production blockchain networks. To overcome this, we created Virtualchain, a logical layer for implementing arbitrary fork*-consistent replicated state machines (RSMs) on top of already-running blockchains. Blockchains provide a totally-ordered, tamper-resistant journal of stat...

An automated recovery system is a key component in a large data center. Such a system typically employs a hand-made controller created by an expert. While such controllers capture many important aspects of the recovery process, they are often not systematically optimized to reduce costs such as server downtime. In this paper we describe a passive policy learning approach for improving existing ...

Enchanced survival of ultraviolet-irradiated Escherichia coli dependent upon the recA + gene appears to result from the ability to seal gaps in newly synthesized deoxyribonucleic acid (DNA) produced when DNA containing pyrimidine dimers is replicated (8). Strains which are recombination-deficient (recA) do not seal these gaps and degrade their DNA to a considerable extent. Rupp and Howard-Fland...

This note illustrates a simple theoretical model in which rival brands compete in positioning strategies and prices. The model provides an interpretation of brand positioning in a familiar spatial model. The ability of firms to observe promotional choices of their rivals affords them higher price margins through differentiation. Finally a reaction function analysis suggests that when a rival po...

Semantic Web is expected to become an enhanced information foundation for both humans and machines. Once data on the WWW is annotated with machine understandable metadata linked to ontology, complex tasks can be automated using software agents. Among the issues surrounding the Semantic Web, difficulties in designing metadata act as a bottleneck to widespread adoption of the Semantic Web. This i...

In many real-life applications of house allocation problems, whenever an existing tenant wants to move, he needs to give up his current house before getting another one. This practice discourages existing tenants from such attempts and results in loss of potentially large gains from trade. Motivated by this observation, we propose a simple mechanism that is Pareto efficient, individually ration...