Quantifying the Effect of Matrix Structure on Multithreaded Performance of the SpMV Kernel

Sparse matrix-vector multiplication (SpMV) is the core operation in many common network and graph analytics, but poor performance of the SpMV kernel handicaps these applications. This work quantifies the effect of matrix structure on SpMV performance, using Intel's VTune tool for the Sandy Bridge architecture. Two types of sparse matrices are considered: finite difference (FD) matrices, which are structured, and R-MAT matrices, which are unstructured. Analysis of cache behavior and prefetcher activity reveals that the SpMV kernel performs far worse with R-MAT matrices than with FD matrices, due to the difference in matrix structure. To address the problems caused by unstructured matrices, novel architecture improvements are proposed.Comment: 6 pages, 7 figures. IEEE HPEC 201

Conformal GaP layers on Si wire arrays for solar energy applications

We report conformal, epitaxial growth of GaP layers on arrays of Si microwires. Silicon wires grown using chlorosilane chemical vapor deposition were coated with GaP grown by metal-organic chemical vapor deposition. The crystalline quality of conformal, epitaxial GaP/Si wire arrays was assessed by transmission electron microscopy and x-ray diffraction. Hall measurements and photoluminescence show p- and n-type doping with high electron mobility and bright optical emission. GaP pn homojunction diodes on planar reference samples show photovoltaic response with an open circuit voltage of 660 mV

Dynamic Video Streaming for Nano Quadcopters

The objective of this project was to develop a system that streams real-time video from a Crazyflie 2.0 nano quadcopter. We discuss the motivation behind the project including applications to swarm robotics and computer vision research. We highlight the initial research and design goals that guided the development of the system such as hardware selection and system specifications. We detail the software and hardware subsystems that we implemented including the video-streaming board, firmware, and video-streaming user application. We examine the performance of the final system and discuss the limitations imposed by the hardware. We conclude by describing future work that will enhance the capabilities and robustness of the system

A Preliminary Study on Expanding and Financing State Water Development

The effects of recent energy price increases, domestic inflation rates, financial market fluctuations, and changing public attitudes toward federally sponsored water resource development and management have brought economic and financial consideratiosn to the forefront of Western water management issues. Recently enacted federal policies place increased responsibility on the states and localities for the development and management of their water resources. A response common to many of the western states has been to stengthen traditional, and often small, water financing and development programs. In creating and sustaining such a posture, however, state governments must address the important questions pertaining to the economic and financial impact of greater state involvement, the distributional impacts of state taxing and lending programs, and the state social goals relating to such managerial involvement. The traditional and recently expanded water development programs of the State of Utah have been reviewed in the light of such management issues. The demand for state financing of water projects was addressed through an examination of economic indicators and an inventory of potential projects. State options for obtaining capital financing also were examined. This review indicates taht increased financing activity and the potential for increased concentration of water development project benefits to specific social groups have created a need for greater clarity in the legislative mandate and greater accounting and visibility of water project impacts through the use of improved economic and social evalution procedures. Moreover, in the absence of such safeguards, the continued investment of state funds might be considered premature and not always in the best interest of the state\u27s residents

Beyond Happiness and Satisfaction: Toward Well-Being Indices Based on Stated Preference [post-print]

This paper proposes foundations and a methodology for survey-based tracking of well-being. First, we develop a theory in which utility depends on fundamental aspects of well-being, measurable with surveys. Second, drawing from psychologists, philosophers, and economists, we compile a comprehensive list of such aspects. Third, we demonstrate our proposed method for estimating the aspects\u27 relative marginal utilities—a necessary input for constructing an individual-level well-being index—by asking ~4,600 U.S. survey respondents to state their preference between pairs of aspect bundles. We estimate high relative marginal utilities for aspects related to family, health, security, values, freedom, happiness, and life satisfaction

Classical Trajectories for Complex Hamiltonians

It has been found that complex non-Hermitian quantum-mechanical Hamiltonians may have entirely real spectra and generate unitary time evolution if they possess an unbroken \cP\cT symmetry. A well-studied class of such Hamiltonians is $H= p^2+x^2(ix)^\epsilon$ ($\epsilon\geq0$). This paper examines the underlying classical theory. Specifically, it explores the possible trajectories of a classical particle that is governed by this class of Hamiltonians. These trajectories exhibit an extraordinarily rich and elaborate structure that depends sensitively on the value of the parameter $\epsilon$ and on the initial conditions. A system for classifying complex orbits is presented.Comment: 24 pages, 34 figure

A survey of the relative merits of the single and double session plans of elementary school organization

Thesis (Ed.M.)--Boston Universit

Speciation in Duckweeds (Lemnaceae): Phylogenetic and Ecological Inferences

Species of duckweeds (Letnnaceae) that were resolved as sister taxa in a phylogeny based on combined molecular and non-molecular data were compared for morphological, physiological, and ecological attributes to infer factors important in the initial divergence leading to speciation. The ability to survive extreme conditions such as desiccation and cold temperatures is the most common difference identified between species. Two morphological characters facilitating survival in extreme environments are production of special resting buds called turions and increased seed production. The prevalent geographic pattern for species pairs consists of one restricted species occurring on the periphery of a more widespread taxon; this pattern indicates that divergence of peripheral isolates is a common geographical mode of speciation in duckweeds. Other species differ in optimal environmental conditions for growth, and these species are largely sympatric. In only one instance does it appear that divergence and speciation occurred following long-distance dispersal. Sympatric species pairs have the lowest molecular divergence; widespread primarily allopatric, and distantly allopatric species have the highest molecular divergence. Despite infrequent sexual reproduction, some degree of detectable variation (molecular, physiological, etc.) occurs within populations and among populations of the same species. Molecular evidence indicates that variation within duckweeds extends from the population and intraspecific levels to very different levels of divergence among recognized species. Contrary to the appearance of morphological and ecological uniformity implied by their reduced morphology and restricted occurrence in fresh water habitats, duckweeds are not a group in evolutionary stasis. Rather, these smallest of all flowering plants are dynamic evolutionarily, and comprise a model system for studying plant evolution and speciation

What Do You Think Would Make You Happier? What Do You Think You Would Choose?

Would people choose what they think would maximize their subjective well-being (SWB)? We present survey respondents with hypothetical scenarios and elicit both choice and predicted SWB rankings of two alternatives. While choice and predicted SWB rankings usually coincide in our data, we find systematic reversals. We identify factors—such as predicted sense of purpose, control over one\u27s life, family happiness, and social status—that help explain hypothetical choice controlling for predicted SWB. We explore how our findings vary by SWB measure and by scenario. Our results have implications regarding the use of SWB survey questions as a proxy for utility

FoxP2 isoforms delineate spatiotemporal transcriptional networks for vocal learning in the zebra finch.

Human speech is one of the few examples of vocal learning among mammals yet ~half of avian species exhibit this ability. Its neurogenetic basis is largely unknown beyond a shared requirement for FoxP2 in both humans and zebra finches. We manipulated FoxP2 isoforms in Area X, a song-specific region of the avian striatopallidum analogous to human anterior striatum, during a critical period for song development. We delineate, for the first time, unique contributions of each isoform to vocal learning. Weighted gene coexpression network analysis of RNA-seq data revealed gene modules correlated to singing, learning, or vocal variability. Coexpression related to singing was found in juvenile and adult Area X whereas coexpression correlated to learning was unique to juveniles. The confluence of learning and singing coexpression in juvenile Area X may underscore molecular processes that drive vocal learning in young zebra finches and, by analogy, humans