How a rainbow coloring function can simulate wait-free handshaking

How to construct shared data objects is a fundamental issue in asynchronous concurrent systems, since these objects provide the means for communication and synchronization between processes in these systems. Constructions which guarantee that concurrent access to the shared object by processes is free from waiting are of particular interest, since they may help to increase the amount of parallelism in such systems. The problem of constructing a k-valued wait-free shared register out of binary subregisters of the same type where each write access consists of one subwrite (constructions with one-write) has received some attention, since it lies at the heart of studying lower bounds of the complexities of register constructions and trade-offs between them. The first such construction was for the safe register case which uses k binary safe registers and exploits the properties of a rainbow coloring function of a hypercube. The best known construction for the regular/atomic case uses (formula presented) binary regular/atomic registers. In this work we show how the rainbow coloring function can be extended to simulate a handshaking mechanism between the reader and the writer of the register, thus offering a solution for the atomic register case with one reader, which uses only 3k-2 binary registers. The lower bound for such a construction is k−1

How a rainbow coloring function can simulate wait-free handshaking

How to construct shared data objects is a fundamental issue in asynchronous concurrent systems, since these objects provide the means for communication and synchronization between processes in these systems. Constructions which guarantee that concurrent access to the shared object by processes is free from waiting are of particular interest, since they may help to increase the amount of parallelism in such systems. The problem of constructing a k-valued wait-free shared register out of binary subregisters of the same type where each write access consists of one subwrite (constructions with one-write) has received some attention, since it lies at the heart of studying lower bounds of the complexities of register constructions and trade-offs between them. The first such construction was for the safe register case which uses k binary safe registers and exploits the properties of a rainbow coloring function of a hypercube. The best known construction for the regular/atomic case uses (formula presented) binary regular/atomic registers. In this work we show how the rainbow coloring function can be extended to simulate a handshaking mechanism between the reader and the writer of the register, thus offering a solution for the atomic register case with one reader, which uses only 3k-2 binary registers. The lower bound for such a construction is k−1

Technical Reports: Langley Aerospace Research Summer Scholars

The Langley Aerospace Research Summer Scholars (LARSS) Program was established by Dr. Samuel E. Massenberg in 1986. The program has increased from 20 participants in 1986 to 114 participants in 1995. The program is LaRC-unique and is administered by Hampton University. The program was established for the benefit of undergraduate juniors and seniors and first-year graduate students who are pursuing degrees in aeronautical engineering, mechanical engineering, electrical engineering, material science, computer science, atmospheric science, astrophysics, physics, and chemistry. Two primary elements of the LARSS Program are: (1) a research project to be completed by each participant under the supervision of a researcher who will assume the role of a mentor for the summer, and (2) technical lectures by prominent engineers and scientists. Additional elements of this program include tours of LARC wind tunnels, computational facilities, and laboratories. Library and computer facilities will be available for use by the participants

Maritime expressions:a corpus based exploration of maritime metaphors

This study uses a purpose-built corpus to explore the linguistic legacy of Britain’s maritime history found in the form of hundreds of specialised ‘Maritime Expressions’ (MEs), such as TAKEN ABACK, ANCHOR and ALOOF, that permeate modern English. Selecting just those expressions commencing with ’A’, it analyses 61 MEs in detail and describes the processes by which these technical expressions, from a highly specialised occupational discourse community, have made their way into modern English. The Maritime Text Corpus (MTC) comprises 8.8 million words, encompassing a range of text types and registers, selected to provide a cross-section of ‘maritime’ writing. It is analysed using WordSmith analytical software (Scott, 2010), with the 100 million-word British National Corpus (BNC) as a reference corpus. Using the MTC, a list of keywords of specific salience within the maritime discourse has been compiled and, using frequency data, concordances and collocations, these MEs are described in detail and their use and form in the MTC and the BNC is compared. The study examines the transformation from ME to figurative use in the general discourse, in terms of form and metaphoricity. MEs are classified according to their metaphorical strength and their transference from maritime usage into new registers and domains such as those of business, politics, sports and reportage etc. A revised model of metaphoricity is developed and a new category of figurative expression, the ‘resonator’, is proposed. Additionally, developing the work of Lakov and Johnson, Kovesces and others on Conceptual Metaphor Theory (CMT), a number of Maritime Conceptual Metaphors are identified and their cultural significance is discussed