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Full-Text Articles in Physical Sciences and Mathematics

Measuring The Effects Of Thread Placement On The Kendall Square Ksr1, Amy Apon, T D. Wagner, E Smirni, M Madhukar, L W. Dowdy Aug 1993

Measuring The Effects Of Thread Placement On The Kendall Square Ksr1, Amy Apon, T D. Wagner, E Smirni, M Madhukar, L W. Dowdy

Publications

This paper describes a measurement study of the effects of thread placement on memory access times on the Kendall Square multiprocessor, the KSRl. The KSRl uses a conventional shared memory programming model in a distributed memory architecture. The architecture is based on a ring of rings of 64-bit superscalar microprocessors. The KSRl has a Cache-Only Memory Architecture (COMA). Memory consists of the local cache memoria attached to each processor. Whenever an address is accessed, the data item is automatically copied to the local cache memory module, 80 that access times for subsequent references will be minimal. If a local cache ...


Gravity Wave-Driven Fluctuations In The O2 Atmospheric (0-1) Nightglow From An Extended, Dissipative Emission Region, Michael P. Hickey Ph.D., G. Schubert, R. L. Walterscheid Aug 1993

Gravity Wave-Driven Fluctuations In The O2 Atmospheric (0-1) Nightglow From An Extended, Dissipative Emission Region, Michael P. Hickey Ph.D., G. Schubert, R. L. Walterscheid

Publications

The wave-driven fluctuations in the O2(0-1) atmospheric nightglow is modeled and the parameter (eta) is calculated using a model that accounts for either three-body recombination of atomic oxygen atoms alone to form the O2(b exp 1 Sigma(g)(+)) state directly, or by the further inclusion of the process that allows the formation of the O2(c exp 1 Sigma(u)(-)) intermediate state. The calculations are performed for a latitude of 18 deg N and for the months of March and June. The general results, which display how (eta) varies with wave period, horizontal wavelength, season, and chemical scheme ...


An Alternative Representation Of The Ice Canopy For Calculating Microwave Brightness Temperatures Over A Thunderstorm, Bradley M. Muller, Henry E. Fuelberg, Eric A. Smith May 1993

An Alternative Representation Of The Ice Canopy For Calculating Microwave Brightness Temperatures Over A Thunderstorm, Bradley M. Muller, Henry E. Fuelberg, Eric A. Smith

Publications

Passive microwave brightness temperatures (T(B)'s) at 92 and 183 GHz from an aircraft thunderstorm overflight are compared with values calculated from radar-derived hydrometeor profiles and a modified proximity sounding. Two methods for modeling particles in the ice canopy are contrasted. The first is a ''traditional'' approach employing Marshall-Palmer ice spheres. The second, or ''alternative,'' method partitions 20% of the ice water content into a Marshall-Palmer component for graupel and hail, and 80% into a modified gamma spherical particle size distribution function representing ice crystals.

Results from the alternative approach are superior to those from the traditional method in ...


The Ksr1: Experimentation And Modeling Of Poststore, Amy Apon, E Rosti, E Smirni, T D. Wagner, M Madhukar, L W. Dowdy Feb 1993

The Ksr1: Experimentation And Modeling Of Poststore, Amy Apon, E Rosti, E Smirni, T D. Wagner, M Madhukar, L W. Dowdy

Publications

Kendall Square Research introduced the KSRl system in 1991. The architecture is based on a ring of rings of 64bit microprocessors. It is a distributed, shared memory system and is scalable. The memory structure is unique and is the key to understanding the system. Different levels of caching eliminates physical memory addressing and leads to the ALLCACHE TM scheme. Since requested data may be found in any of several caches, the initial access time is variable. Once pulled into the local (sub)cache, subsequent access times are fixed and minimal. Thus, the KSRl is a Cache-Only Memory Architecture (COMA) system ...