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KINSHIP AND HISTORY: TRIBES, GENEALOGIES, AND SOCIAL CHANGE AMONG THE BEDOUIN OF THE EASTERN ARAB WORLD
Most scholars of tribal organization among the Bedouin of the eastern Arab world utilize a two-dimensional, hierarchical model of Bedouin kinship that represents only relations of descent and affinity. This model resembles a genealogy and shows how small descent units are enclosed by larger ones. It implies that tribes grow in size only through biological reproduction. Such a representation of the Bedouin tribe fails to distinguish politically central lineages from politically peripheral lineages and also ignores the processes through which foreign lineages become “attached” as clients to politically powerful, central lineages. To correct and supplement this genealogical model, the author presents a concentric model of Bedouin tribes that adds a “central/peripheral” distinction. This model also includes relations of political “attachment” that can affect the internal morphology and growth of Bedouin tribes in ways that are comparable to the effects of affinal and suckling kinship relations on internal organization. The proposed concentric model thus allows us to represent historical change more accurately and also brings us closer to Bedouin concepts of tribal organization
Verifying the interactive convergence clock synchronization algorithm using the Boyer-Moore theorem prover
The application of formal methods to the analysis of computing systems promises to provide higher and higher levels of assurance as the sophistication of our tools and techniques increases. Improvements in tools and techniques come about as we pit the current state of the art against new and challenging problems. A promising area for the application of formal methods is in real-time and distributed computing. Some of the algorithms in this area are both subtle and important. In response to this challenge and as part of an ongoing attempt to verify an implementation of the Interactive Convergence Clock Synchronization Algorithm (ICCSA), we decided to undertake a proof of the correctness of the algorithm using the Boyer-Moore theorem prover. This paper describes our approach to proving the ICCSA using the Boyer-Moore prover
Machine-checked proofs of the design and implementation of a fault-tolerant circuit
A formally verified implementation of the 'oral messages' algorithm of Pease, Shostak, and Lamport is described. An abstract implementation of the algorithm is verified to achieve interactive consistency in the presence of faults. This abstract characterization is then mapped down to a hardware level implementation which inherits the fault-tolerant characteristics of the abstract version. All steps in the proof were checked with the Boyer-Moore theorem prover. A significant results is the demonstration of a fault-tolerant device that is formally specified and whose implementation is proved correct with respect to this specification. A significant simplifying assumption is that the redundant processors behave synchronously. A mechanically checked proof that the oral messages algorithm is 'optimal' in the sense that no algorithm which achieves agreement via similar message passing can tolerate a larger proportion of faulty processor is also described
Refraction of swell by surface currents
Using recordings of swell from pitch-and-roll buoys, we have reproduced the
classic observations of long-range surface wave propagation originally made by
Munk et al. (1963) using a triangular array of bottom pressure measurements. In
the modern data, the direction of the incoming swell fluctuates by about on a time scale of one hour. But if the incoming direction is
averaged over the duration of an event then, in contrast with the observations
by Munk et al. (1963), the sources inferred by great-circle backtracking are
most often in good agreement with the location of large storms on weather maps
of the Southern Ocean. However there are a few puzzling failures of
great-circle backtracking e.g., in one case, the direct great-circle route is
blocked by the Tuamoto Islands and the inferred source falls on New Zealand.
Mirages like this occur more frequently in the bottom-pressure observations of
Munk et al. (1963), where several inferred sources fell on the Antarctic
continent.
Using spherical ray tracing we investigate the hypothesis that the refraction
of waves by surface currents produces the mirages. With reconstructions of
surface currents inferred from satellite altimetry, we show that mesoscale
vorticity significantly deflects swell away from great-circle propagation so
that the source and receiver are connected by a bundle of many rays, none of
which precisely follow a great circle. The directional
fluctuations at the receiver result from the arrival of wave packets that have
travelled along the different rays within this multipath. The occasional
failure of great-circle backtracking, and the associated mirages, probably
results from partial topographic obstruction of the multipath, which biases the
directional average at the receiver.Comment: Journal of Marine Research, in pres
Body Talk: Male Athletes Reflect on Sport, Injury, and Pain
This paper examines how participation in physically demanding sport, with its potential and actual injurious outcomes, both challenges and reinforces dominant notions of masculinity. Data from 16 in-depth interviews with former and current Canadian adult male athletes indicate that sport practices privileging forceful notions of masculinity are highly valued, and that serious injury is framed as a masculinizing experience. It is argued that a generally unreflexive approach to past disablement is an extraordinary domain feature of contemporary sport. The risks associated with violent sport appear to go relatively unquestioned by men who have suffered debilitating injury and whose daily lives are marked by physical constraints and pain
Synthesis and Reactivity of Tricarbonyl(1-ethoxy-carbonyl-2-methylpentadienyl)iron(1+) Cation
The title cation was prepared in two steps from the known (ethyl 3-methyl-6-oxo-2,4-hexadienoate)Fe(CO)3. Reation of the cation with NaBH3CN, methyl cuprate, phthalimide, water, PPh3, or malonate anions gave predominantly the products from nucleophilic attack at the C5 pentadienyl carbon
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