PARALLEX FILE SYSTEM (PXFS): BRIDGING THE GAP BETWEEN EXASCALE PROCESSING CAPABILITIES AND I/O PERFORMANCE

Due to processors reaching the maximum performance allowable by current technology, architectural trends for computer systems continue to increase the number of cores per processing chip to maximize system performance. Most estimates suggest massively parallel systems will be available within the decade, containing millions of cores and capable of exaFlops of performance. New models of execution are necessary to maximize processor utilization and minimize power costs for these exascale systems. ParalleX is one such execution model, which attempts to address inefficiencies of current execution models by exposing fine-grained parallelism, increasing system utilization using asynchronous workflow, and resolving resource contention through the use of adaptive and dynamic resource scheduling. A particularly important aspect of these exascale execution models is the design of the I/O subsystem, which has seen limited performance increases compared to processor and network technologies. Parallel file systems have been designed to help alleviate the poor performance of storage technologies by distributing file data across multiple nodes of a parallel system to maximize the aggregate throughput attainable by file system clients. However, the design of parallel file systems needs to be modified to explicitly address the inherent high-latency of remote file system operations without degrading file system performance and scalability. We present modifications to OrangeFS, a high-performance, working model parallel file system geared towards the facilitation of research in the field of parallel I/O, to help address the inefficiencies of current file systems. We deem our resultant parallel file system implementation ParalleX File System (PXFS), as it attempts to support the features required by the I/O subsystem of the ParalleX execution model. Specifically, PXFS offers mechanisms for masking the latency of file system operations, defining meaningful computation to be overlapped with file system communication, and maintaining the high-performance and scalability exhibited by OrangeFS. Our results indicate PXFS successfully improves file system performance and supports the semantics of ParalleX with limited programmer intervention, potentially simplifying the design and increasing the performance of many ParalleX applications

Understanding Hope: A Review of Measurement and Construct Validity Research

Hope has been discussed by philosophers, theologians, educators, and scientists, to name but a few groups of people, over the preceding two millennia. During the last 15 years, C. R. Snyder and his colleagues at the University of Kansas have developed a theory and associated measures of the hope construct that have received extensive, detailed attention both within and outside the field of psychology. In this chapter, we describe Snyder\u27s hope model and some of the research findings that have supported the validity of this construct. Beginning with a conceptual definition of hope, we move to relevant findings about the usefulness of hope in the lives of individuals in various life arenas. We describe measures developed for assessing hope in children and adults, as well as current issues associated with the validity of hope measurement. Finally, we discuss future directions for further investigation of hope

Teachers\u27 Perceptions of Digital Citizenship Development in Middle School Students Using Social Media and Global Collaborative Projects

Middle school students misuse social media without understanding the negative influence on their global digital footprint and lives. Research does not provide insight into how students develop digital citizenship skills for positive digital footprints and appropriate social media use. The purpose of this qualitative case study was to explore students\u27 growth as digital citizens while participating in one digital citizenship project using global collaboration and social media. The conceptual framework included Ribble\u27s theory of digital citizenship and Siemens\u27s theory of connectivism. Research questions asked how students\u27 digital citizenship developed when they were engaged in social media and global collaborative projects. Participants included 7 middle school teachers and 1 project administrator. Structured interviews and Wiki data were analyzed using an iterative open coding technique to identify rich, thick themes and patterns. The findings showed global collaborative projects and social media served as catalysts to motivate students as they took action as digital citizens, overcame barriers to digital citizenship, used social media for learning and collaboration, and adopted less ethnocentric views of the world. Students compared other cultures to their own, considered the welfare of others online, and modified their online behavior in favor of positive global digital footprints. Students used social media responsibly, were academically motivated by an authentic audience, and shared their academic learning with others in their local and extended communities. Reform of middle school curricula to include global collaborative projects and instruction in digital citizenship may bring about positive social change as students learn to be responsible users of social media

Toward understanding I/O behavior in HPC workflows

Scientific discovery increasingly depends on complex workflows consisting of multiple phases and sometimes millions of parallelizable tasks or pipelines. These workflows access storage resources for a variety of purposes, including preprocessing, simulation output, and postprocessing steps. Unfortunately, most workflow models focus on the scheduling and allocation of com- putational resources for tasks while the impact on storage systems remains a secondary objective and an open research question. I/O performance is not usually accounted for in workflow telemetry reported to users. In this paper, we present an approach to augment the I/O efficiency of the individual tasks of workflows by combining workflow description frameworks with system I/O telemetry data. A conceptual architecture and a prototype implementation for HPC data center deployments are introduced. We also identify and discuss challenges that will need to be addressed by workflow management and monitoring systems for HPC in the future. We demonstrate how real-world applications and workflows could benefit from the approach, and we show how the approach helps communicate performance-tuning guidance to users

The effect of tertiary treated wastewater on fish growth and health: Laboratory-scale experiment with Poecilia reticulata (guppy)

Treated wastewater (TWW) constitutes a sustainable water resource and has been used for fish culture in some countries around the world, although there are no comprehensive data on the effect of TWW on fish growth and health in the context of aquaculture production. Our objectives were to examine how fish culture in TWW affected fish growth and fitness, as well as compliance with the international standards for safe consumption. Guppy (Poecilia reticulata) fingerlings were reared in 0%, 50% and 100% tertiary TWW (TTWW), from the age of five days, for a period of four months. In water analyses, 33 out of 67 tested organic micropollutants (OMPs) were detected in the TTWW samples at least once, at concentrations that are typically reported in domestic TTWW. Fish survival ranged between 77-80% and did not differ between treatment groups. Fish growth and mortality following challenge infection with Tetrahymena sp. (which ranged between 64-68%), were similar among treatment groups. Of tested immunological parameters, lysozyme and anti-protease was similar among treatments while complement activity was highest in the 50% TTWW-reared fish. No abnormalities were observed in the histopathological analysis. Levels of heavy metals, poly-chlorinated-biphenyls (PCBs) and organochlorines (OCs) in fish were below the detection limit and below the Food and Agriculture Organization of the United Nations (FAO) and the European Union EU maximal permitted levels in food fish. Results suggest that the yield of fish grown in TTWW is potentially similar to that in freshwater, and the produced fish comply with the standards of consumer safety. The results are in line with previous studies that examined the feasibility of TWW-fed aquaculture.Jewish Charitable Association (ICA); Israel Ministry of Science and Technology [3-12876]Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

An exploration of infant and toddler unstructured outdoor play

Unstructured outdoor play is important for children\u27s development. The present study examined infants’ and toddlers’ physical and social unstructured outdoor play behaviors within childcare centers. Children\u27s outdoor play behaviors were video recorded at two centers (A&B) and assessed using a modified version of the Observational System for Recording Physical Activity in Children in Preschool (OSRAC-P). Children in this study primarily took part in active play (56.7%) and engaged in play without any type of prompting from a teacher (91.2%). There was a significant interaction between the effect of center and location on physically active play (p \u3c 0.001). Children at Center B were most active in open play areas (77.6%), while children at Center A were most active in gross motor play areas (72.2%). In sum, the outdoor play environment influences infants’ and toddlers’ physical and social play behaviors; however, more research is needed to determine the optimal environment for development

Exploring Secondary Science Teachers\u27 Use of Classroom Physical Activity

This study explored the use of classroom physical activity (PA) in secondary science rooms. To accomplish this, semistructured interviews were conducted with secondary science teachers (n = 11). Interviews were based on the constructs of the social-ecological model. Most teachers reported using classroom PA in some form—in-class breaks, outdoor activities, and curriculum support. Teachers used classroom PA to improve academic and behavioral outcomes of students. They had varied perceptions regarding collegial support of classroom PA, but mostly felt supported by administrators. Teachers reported being unaware of their district’s and the state department of education’s beliefs about classroom PA. Overall, factors that negatively influenced classroom PA use tended to be within the interpersonal, organization, and policy levels of the social-ecological model, while factors that positively influenced classroom PA use tended to be within the individual level

Apportionment of primary and secondary organic aerosols in Southern California during the 2005 Study of Organic Aerosols in Riverside (SOAR-1)

Ambient sampling was conducted in Riverside, California during the 2005 Study of Organic Aerosols in Riverside to characterize the composition and sources of organic aerosol using a variety of state-of-the-art instrumentation and source apportionment techniques. The secondary organic aerosol (SOA) mass is estimated by elemental carbon and carbon monoxide tracer methods, water soluble organic carbon content, chemical mass balance of organic molecular markers, and positive matrix factorization of high-resolution aerosol mass spectrometer data. Estimates obtained from each of these methods indicate that the organic fraction in ambient aerosol is overwhelmingly secondary in nature during a period of several weeks with moderate ozone concentrations and that SOA is the single largest component of PM1 aerosol in Riverside. Average SOA/OA contributions of 70−90% were observed during midday periods, whereas minimum SOA contributions of ~45% were observed during peak morning traffic periods. These results are contrary to previous estimates of SOA throughout the Los Angeles Basin which reported that, other than during severe photochemical smog episodes, SOA was lower than primary OA. Possible reasons for these differences are discussed