Region-based memory management for Mercury programs

Region-based memory management (RBMM) is a form of compile time memory management, well-known from the functional programming world. In this paper we describe our work on implementing RBMM for the logic programming language Mercury. One interesting point about Mercury is that it is designed with strong type, mode, and determinism systems. These systems not only provide Mercury programmers with several direct software engineering benefits, such as self-documenting code and clear program logic, but also give language implementors a large amount of information that is useful for program analyses. In this work, we make use of this information to develop program analyses that determine the distribution of data into regions and transform Mercury programs by inserting into them the necessary region operations. We prove the correctness of our program analyses and transformation. To execute the annotated programs, we have implemented runtime support that tackles the two main challenges posed by backtracking. First, backtracking can require regions removed during forward execution to be "resurrected"; and second, any memory allocated during a computation that has been backtracked over must be recovered promptly and without waiting for the regions involved to come to the end of their life. We describe in detail our solution of both these problems. We study in detail how our RBMM system performs on a selection of benchmark programs, including some well-known difficult cases for RBMM. Even with these difficult cases, our RBMM-enabled Mercury system obtains clearly faster runtimes for 15 out of 18 benchmarks compared to the base Mercury system with its Boehm runtime garbage collector, with an average runtime speedup of 24%, and an average reduction in memory requirements of 95%. In fact, our system achieves optimal memory consumption in some programs.Comment: 74 pages, 23 figures, 11 tables. A shorter version of this paper, without proofs, is to appear in the journal Theory and Practice of Logic Programming (TPLP

Hypercube technology

The JPL designed MARKIII hypercube supercomputer has been in application service since June 1988 and has had successful application to a broad problem set including electromagnetic scattering, discrete event simulation, plasma transport, matrix algorithms, neural network simulation, image processing, and graphics. Currently, problems that are not homogeneous are being attempted, and, through this involvement with real world applications, the software is evolving to handle the heterogeneous class problems efficiently

Interpretation of remote sensing data in the Bayou LaFourche delta of south Louisiana

There are no author-identified significant results in this report

JPL bibliography 39-12 - Prerelease for December 1970

Bibliography of technical reports on scientific and engineering studies, December 197

Space programs summary no. 37-63, volume 1 for the period 1 March - 30 April 1970. Flight projects

Mariner Mars 1971, Mariner Venus-Mercury 1973 and Viking Orbiter 1975 status report

Bad Water 2009: The Impact on Human Health in the Chesapeake Bay Region

The report links pollution to human health risks and calls on the federal Environmental Protection Agency (EPA) to act now to reduce that pollution and the potential threats to human health

The Benefits and Costs of Fish Consumption Advisories for Mercury

Mercury contamination of the Chesapeake Bay is a concern to health authorities in the region. We evaluate the economic and health effects of postulated recreational and commercial fishing advisories for striped bass on the Maryland portion of the bay. Awareness of and response to the advisory is estimated using a meta-analysis of the literature. Three values are estimated: welfare losses to recreational anglers, welfare losses in the commercial striped bass fishery, and health benefits. An estimate of percentage of consumer surplus loss is applied to the value of all fishing days in the bay to estimate recreational welfare loss. Welfare losses to the commercial fishery are estimated based on a model of supply and demand. Health benefits are estimated using estimated exposure and epidemiological relationships, and while potentially large, are highly uncertain. Results also suggest most individuals are below advisory standards ex ante, such that advisories should target high-frequency consumers.fisheries, mercury, advisories, recreation, health benefits

A Balanced Energy Plan for the Interior West

Describes a Balanced Energy Plan for the Interior West region of Arizona, New Mexico, Nevada, Utah, Colorado, Wyoming and Montana. Part of the Hewlett Foundation Energy Series