Transactional memory (TM) promises to substantially reduce the difficulty of writing correct, efficient, and scalable concurrent programs. But "bounded" and "best-effort" hardware TM proposals impose unreasonable constraints on programmers, while more flexible software TM implementations are considered too slow. Proposals for supporting "unbounded" transactions in hardware entail significantly higher complexity and risk than best-effort designs.We introduce Hybrid Transactional Memory (HyTM), an approach to implementing TM in software so that it can use best-effort hardware TM (HTM) to boost performance but does not depend on HTM. Thus programmers can develop and test transactional programs in existing systems today, and can enjoy the performance benefits of HTM support when it becomes available.We describe our prototype HyTM system, comprising a compiler and a library. The compiler allows a transaction to be attempted using best-effort HTM, and retried using the software library if it fails. We have used our prototype to "transactify" part of the Berkeley DB system, as well as several benchmarks. By disabling the optional use of HTM, we can run all of these tests on existing systems. Furthermore, by using a simulated multiprocessor with HTM support, we demonstrate the viability of the HyTM approach: it can provide performance and scalability approaching that of an unbounded HTM implementation, without the need to support all transactions with complicated HTM support.

We report on our experience with the hardware transactional memory (HTM) feature of two pre-production revisions of a new commercial multicore processor. Our experience includes a number of promising results using HTM to improve performance in a variety of contexts, and also identifies some ways in which the feature could be improved to make it even better. We give detailed accounts of our experiences, sharing techniques we used to achieve the results we have, as well as describing challenges we faced in doing so.

This paper shows for the first time that elimination, a scaling technique formerly applied only to counters and LIFO structures, can be applied to FIFO data structures, specifically, to linearizable FIFO queues. We show how to transform existing nonscalable FIFO queue implementations into scalable implementations using the elimination technique, while preserving lock-freedom and linearizablity.We apply our transformation to the FIFO queue algorithm of Michael and Scott, which is included in the Java TM Concurrency Package. Empirical evaluation on a state-ofthe-art CMT multiprocessor chip shows that by using elimination as a backoff technique for the Michael and Scott queue algorithm, we can achieve comparable performance at low loads, and improved scalability as load increases.

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Fuel requirements on the battlefield impose direct costs associated with the resources necessary to transport the fuel and protect logistics assets, in addition to indirect energy security costs. Estimating the enterprise-wide demand for fuel associated with fuel consumption on the battlefield is a challenging, but necessary, step to making good decisions. This paper presents a modeling framework for estimating the enterprise-wide fuel requirements associated with a multistage fuel supply chain, demonstrating a multiplicative increase in fuel demand with additional stages, and examining the fuel impact of protecting the supply chain.

Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to a penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. REPORT DATE APR 20112. REPORT TYPE 3. DATES COVERED 00-00-2011 to 00-00-2011 4 Preface & AcknowledgementsDuring his internship with the Graduate School of Business & Public Policy in June 2010, U.S. Air Force Academy Cadet Chase Lane surveyed the activities of the Naval Postgraduate School's Acquisition Research Program in its first seven years. The sheer volume of research products-almost 600 published papers (e.g., technical reports, journal articles, theses)-indicates the extent to which the depth and breadth of acquisition research has increased during these years. Over 300 authors contributed to these works, which means that the pool of those who have had significant intellectual engagement with acquisition issues has increased substantially. The broad range of research topics includes acquisition reform, defense industry, fielding, contracting, interoperability, organizational behavior, risk management, cost estimating, and many others. Approaches range from conceptual and exploratory studies to develop propositions about various aspects of acquisition, to applied and statistical analyses to test specific hypotheses. Methodologies include case studies, modeling, surveys, and experiments. On the whole, such findings make us both grateful for the ARP's progress to date, and hopeful that this progress in research will lead to substantive improvements in the DoD's acquisition outcomes.As pragmatists, we of course recognize that such change can only occur to the extent that the potential knowledge wrapped up in these products is put to use and tested to determine its value. We take seriously the pernicious effects of the so-called "theorypractice" gap, which would separate the acquisition scholar from the acquisition practitioner, and relegate the scholar's work to mere academic "shelfware." Some design features of our program that we believe help avoid these effects include the following: connecting researchers with practitioners on specific projects; requiring researchers to brief sponsors on project findings as a condition of funding award; "pushing" potentially high-impact research reports (e.g., via overnight shipping) to selected practitioners and policy-makers; and most notably, sponsoring this s...