The cloud, in the past few years, has become the preferred platform for hosting web applications. Many of these web applications store their data in a distributed cloud storage system, which greatly simplifies application development and provides increased availability and reliability. However, with increasing user demand for web applications, these cloud storage systems often become the performance bottleneck. To address the cloud's performance demands, many storage system features, such as strong consistency and transactional support, are often omitted in favour of performance. Nonetheless, transactions remain necessary to ensure data integrity and application correctness. In this thesis, we introduce CrossStitch, which is an efficient transaction processing framework for distributed key-value storage systems. CrossStitch supports general transactions, where transactions include both computation and key accesses. It is specifically optimized for short-lived transactions that are typical of cloud-deployed web applications. In CrossStitch, a transaction is partitioned into a series of components that form a transaction chain. These components are executed and the transaction is propagated along the storage servers instead of being executed on the application server. This chained structure, in which servers only communicate with their immediate neighbours, enables CrossStitch to implement a pipelined version of two-phase commit to ensure transactional atomicity. CrossStitch is able to eliminate a significant amount of setup overhead using this structure by executing the transaction and the atomic commit protocol concurrently. Therefore, CrossStitch provides low latency and efficient transactional support for cloud storage systems. Our evaluation demonstrates that CrossStitch is a scalable and efficient transaction processing framework for web transactions.

A claim of Leland (1985) states that in the presence of transaction costs a call option on a stock S, described by geometric Brownian motion, can be perfectly hedged using Black-Scholes delta hedging with a modified volatility. Recently Kabanov and Safarian (1997) disproved this claim, giving an explicit (up to an integral) expression of the limiting hedging error, which appears to be strictly negative and depends on the path of the stock price only via the stock price at expiry ST . We prove in this paper that the limiting hedging error, considered as a function of ST, exhibits a removable discontinuity at the exercise price. Furthermore, we provide a quantitative result describing the evolution of the discontinuity, which shows that its precursors can very well be observed also in cases of reasonable length of revision intervals. (author's abstract) / Series: Report Series SFB "Adaptive Information Systems and Modelling in Economics and Management Science"

This thesis addresses the problem of specifying the composition of distributed applications out of existing applications, possibly legacy ones. With the automation of business processes on the increase, more and more applications of this kind are being constructed. The resulting applications can be quite complex, usually long-lived and are executed in a heterogeneous environment. In a distributed environment, long-lived activities need support for fault tolerance and dynamic reconfiguration. Indeed, it is likely that the environment where they are run will change (nodes may fail, services may be moved elsewhere or withdrawn) during their execution and the specification will have to be modified. There is also a need for modularity, scalability and openness. However, most of the existing systems only consider part of these requirements. A new area of research, called workflow management has been trying to address these issues. This work first looks at what needs to be addressed to support the specification and execution of these new applications in a heterogeneous, distributed environment. A co- ordination language (scripting language) is developed that fulfils the requirements of specifying the composition and inter-dependencies of distributed applications with the properties of dynamic reconfiguration, fault tolerance, modularity, scalability and openness. The architecture of the overall workflow system and its implementation are then presented. The system has been implemented as a set of CORBA services and the execution environment is built using a transactional workflow management system. Next, the thesis describes the design of a toolkit to specify, execute and monitor distributed applications. The design of the co-ordination language and the toolkit represents the main contribution of the thesis.

Thesis (Ph. D.)--University of Washington, 1989. / Vita. Includes bibliographical references.

Thesis (Ph. D.)--University of Hong Kong, 2008. / Includes bibliographical references (leaf 113-129) Also available in print.

Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1993. / Vita. Abstract. Includes bibliographical references (leaves 248-260). Also available via the Internet.

Thesis (Ph. D.)--University of Chicago, Dept. of Economics, March 2000. / Includes bibliographical references. Also available on the Internet.

Thesis (Ph. D.)--University of Washington, 1999. / Vita. Includes bibliographical references (leaves 102-106).

Thesis (doctoral) - Freie Universität, Berlin, 2008. / Includes bibliographical references.

Diss.--Fakultät für Betriebswirtschaft--Universität Mannheim, 1984. / Bibliogr. p. 168-187. Index.