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

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

Geographically versus dynamically defined boundary layer cloud regimes and their use to evaluate general circulation model cloud parameterizations

Regimes of tropical low-level clouds are commonly identified according to large-scale subsidence and lower tropospheric stability (LTS). This definition alone is insufficient for the distinction between regimes and limits the comparison of low-level clouds from CloudSat radar observations and the ECHAM5 GCM run with the COSP radar simulator. Comparisons of CloudSat radar cloud altitude-reflectivity histograms for stratocumulus and shallow cumulus regimes, as defined above, show nearly identical reflectivity profiles, because the distinction between the two regimes is dependent upon atmospheric stability below 700 hPa and observations above 1.5 km. Regional subsets, near California and Hawaii, for example, have large differences in reflectivity profiles than the dynamically defined domain; indicating different reflectivity profiles exist under a given large-scale environment. Regional subsets are better for the evaluation of low-level clouds in CloudSat and ECHAM5 as there is less contamination between 2.5 km and 7.5 km from precipitating hydrometeors which obscured cloud reflectivities. Key Points: Identification of low clouds by large-scale dynamics insufficient for radar Stratocumulus and shallow cumulus regimes have nearly identical reflectivities Geographical regions are better for evaluating low-level clouds with a radar. © 2013. American Geophysical Union. All Rights Reserved

A new puzzle for random interaction

We continue a series of numerical experiments on many-body systems with random two-body interactions, by examining correlations in ratios in excitation energies of yrast $J$ = 0, 2, 4, 6, 8 states. Previous studies, limited only to $J$ = 0,2,4 states, had shown strong correlations in boson systems but not fermion systems. By including $J \ge 6$ states and considering different scatter plots, strong and realistic correlations appear in both boson and fermion systems. Such correlations are a challenge to explanations of random interactions.Comment: 4 pages, 4 figure

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