18,510 research outputs found
Queuing Theoretic Analysis of Power-performance Tradeoff in Power-efficient Computing
In this paper we study the power-performance relationship of power-efficient
computing from a queuing theoretic perspective. We investigate the interplay of
several system operations including processing speed, system on/off decisions,
and server farm size. We identify that there are oftentimes "sweet spots" in
power-efficient operations: there exist optimal combinations of processing
speed and system settings that maximize power efficiency. For the single server
case, a widely deployed threshold mechanism is studied. We show that there
exist optimal processing speed and threshold value pairs that minimize the
power consumption. This holds for the threshold mechanism with job batching.
For the multi-server case, it is shown that there exist best processing speed
and server farm size combinations.Comment: Paper published in CISS 201
Approaching Evaluation in Youth Community Informatics
In the Youth Community Informatics project, young people from disadvantaged communities use audio and video recording and editing tools, GPS/GIS, presentation software, graphics, and other digital technologies as the means for addressing community needs. They build community asset maps, document community history, develop exhibits in collaboration with libraries and museums, present cultural heritage, organize political action, operate community radio, create and maintain community technology centers, and express themselves through multiple media. These activities typically involve multiple partners and develop in unpredictable ways in response to community life. In order to understand what they mean in the lives of the youth and the community we need richer evaluation approaches.published or submitted for publicationis peer reviewe
Pion properties at finite density
In this talk, we report our recent work on the pion weak decay constant
(F_pi) and pion mass (m_pi) using the nonlocal chiral quark model with the
finite quark-number chemical potential (mu) taken into account. Considering the
breakdown of Lorentz invariance at finite density, the time and space
components are computed separately, and the corresponding results turn out to
be: F^t_pi = 82.96 MeV and F^s_pi = 80.29 MeV at mu_c ~ 320 MeV, respectively.
Using the in-medium Gell-Mann Oakes-Renner (GOR) relation, we show that the
pion mass increases by about 15% at mu_c.Comment: 5 pages, 2 figures, Talk given at the 4th Asia-Pacific Conference on
Few-Body Problems in Physics 2008 (APFB08), 19 ~ 23 Aug 2008, Depok,
Indonesi
Helices at Interfaces
Helically coiled filaments are a frequent motif in nature. In situations
commonly encountered in experiments coiled helices are squeezed flat onto two
dimensional surfaces. Under such 2-D confinement helices form "squeelices" -
peculiar squeezed conformations often resembling looped waves, spirals or
circles. Using theory and Monte-Carlo simulations we illuminate here the
mechanics and the unusual statistical mechanics of confined helices and show
that their fluctuations can be understood in terms of moving and interacting
discrete particle-like entities - the "twist-kinks". We show that confined
filaments can thermally switch between discrete topological twist quantized
states, with some of the states exhibiting dramatically enhanced
circularization probability while others displaying surprising
hyperflexibility
Using CALIPSO and CloudSat satellite retrievals to evaluate low-level cloud parameterizations in ECHAM5 for cloud-climate feedback implications
Rotations, Risk and Reward: Farming system choice on the Eyre Peninsula of South Australia
A farming systems and rotations trial was conducted at Minnipa on the Eyre Peninsula of South Australia between 1995 and 2001. The results have been presented to local farmers as simple gross margin comparisons (with a relatively low value for the pasture phase if present) in extension publications. The results are reassessed in terms of increased livestock return, and allowing for permanent/family labour and machinery overheads. The relative risk vs return is also considered to explain the acceptance of the research by local farmers.Farm Management, Land Economics/Use,
Decision Support Systems in Australian Agriculture: State of the Art and Future Development
This paper reports and discusses the results of a survey conducted with experts working in the field of decision support systems (DSS) in Australian agriculture. It also reviews the literature on DSS in the light of these experts' responses. The findings from this survey have consolidated our understanding of the current state of DSS in Australian agriculture. The uptake of DSS by farmers has been slow and various issues said to be contributing to this include fear of using computers, time constraints, poor marketing, complexity, lack of local relevance, lack of end-user involvement, and mismatched objectives between developers and users. The future prospect for the development of DSS was generally regarded to be poor. Never-the-less, the authors believe that new DSS which embrace the suggested criteria could be widely accepted by farmers. These criteria mean that to be widely used by farmers, any successful DSS needs to address widespread problems: they need to be location specific, and gain strong support from initial users. They also need to be simple to use, relevant, effective, low cost, and user friendly and it is most likely that farmers would have been involved in their development. We believe that farmers' personalities, and their attitudes towards risk management and decision making, will influence the pattern of adoption of DSS in Australian agriculture while the intergenerational change that is occurring in the management of Australian farms is a positive factor that may encourage more widespread use of these tools.DSS, farmers' decision-making, expert opinion, management decisions, Farm Management, D7, D8, Q12, Q13, Q16,
Cultural Landscapes of War and Political Regeneration
This article examines the production, uses, and reuses of cultural landscapes within contexts of warfare and political change. Ancient concerns over defense and security have led societies to construct fortification features involving extensive modifications to landscapes in many parts of the world. Social memories are often tied to these militarized landscapes, with embedded meanings and values that persist and morph through time. Due to the potential commemorative power offered by militarized landscapes, leadership strategies related to political regeneration can make use of these built environments. Consequently, the significance of these locales is not limited to military functions, as they can be appropriated by later societies for political agendas. The Co Loa site of modern-day Vietnam’s Red River delta, for instance, illustrates such a locality where warfare and politics intersect. Still standing largely intact today, the site’s monumental system of fortification features dominates the local landscape, reflecting broad alterations of the surrounding terrain. Although the system was originally put into place during the Iron Age, later societies have capitalized on the site’s physical and ideological properties for various military and sociopolitical agendas
Prompt Beta Spectroscopy as a Diagnostic for Mix in Ignited NIF Capsules
The National Ignition Facility (NIF) technology is designed to drive
deuterium-tritium (DT) internal confinement fusion (ICF) targets to ignition
using indirect radiation from laser beam energy captured in a hohlraum.
Hydrodynamical instabilities at interfaces in the ICF capsule leading to mix
between the DT fue l and the ablator shell material are of fundamental physical
interest and can affect the performance characteristics of the capsule. In this
Letter we describe new radiochemical diagnostics for mix processes in ICF
capsules with plastic or Be (0.9%Cu) ablator shells. Reactions of high-energy
tritons with shell material produce high-energy -emitters.
We show that mix between the DT fuel and the shell material enhances
high-energy prompt beta emission from these reactions by more than an order of
magnitude over that expected in the absence of mix
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