Jet Physics at the Tevatron

Jets have been used to verify the theory of quantum chromodynamics (QCD), measure the structure of the proton and to search for the physics beyond the Standard Model. In this article, we review the current status of jet physics at the Tevatron, a sqrt(s) = 1.96 TeV p-pbar collider at the Fermi National Accelerator Laboratory. We report on recent measurements of the inclusive jet production cross section and the results of searches for physics beyond the Standard Model using jets. Dijet production measurements are also reported.Comment: 29 pages, 12 figures, submitted to Ann.Rev.Nucl.Part.Sc

HarvOS: Efficient code instrumentation for transiently-powered embedded sensing

We present code instrumentation strategies to allow transiently-powered embedded sensing devices efficiently checkpoint the system's state before energy is exhausted. Our solution, called HarvOS, operates at compile-time with limited developer intervention based on the control-flow graph of a program, while adapting to varying levels of remaining energy and possible program executions at run-time. In addition, the underlying design rationale allows the system to spare the energy-intensive probing of the energy buffer whenever possible. Compared to existing approaches, our evaluation indicates that HarvOS allows transiently-powered devices to complete a given workload with 68% fewer checkpoints, on average. Moreover, our performance in the number of required checkpoints rests only 19% far from that of an "oracle" that represents an ideal solution, yet unfeasible in practice, that knows exactly the last point in time when to checkpoint

Energy harvesting and wireless transfer in sensor network applications: Concepts and experiences

Advances in micro-electronics and miniaturized mechanical systems are redefining the scope and extent of the energy constraints found in battery-operated wireless sensor networks (WSNs). On one hand, ambient energy harvesting may prolong the systems lifetime or possibly enable perpetual operation. On the other hand, wireless energy transfer allows systems to decouple the energy sources from the sensing locations, enabling deployments previously unfeasible. As a result of applying these technologies to WSNs, the assumption of a finite energy budget is replaced with that of potentially infinite, yet intermittent, energy supply, profoundly impacting the design, implementation, and operation of WSNs. This article discusses these aspects by surveying paradigmatic examples of existing solutions in both fields and by reporting on real-world experiences found in the literature. The discussion is instrumental in providing a foundation for selecting the most appropriate energy harvesting or wireless transfer technology based on the application at hand. We conclude by outlining research directions originating from the fundamental change of perspective that energy harvesting and wireless transfer bring about

System support for transiently-powered embedded sensing systems

I sistemi embedded con alimentazione transitoria stanno diventando popolari a causa della loro natura autosufficiente, senza manutenzione e facilmente dispiegabile. Tuttavia, esiste una sfida intrinseca con questi sistemi: possono essere interrotti in modo imprevedibile, poiché la raccolta di energia non garantisce in alcun modo un prevedibile apporto di energia. I riavvii si verificano spesso, il che si traduce in uno spreco di risorse, compresa l'energia, poiché le applicazioni devono reinizializzare e riacquistare lo stato. Di conseguenza, le prestazioni complessive ne soffrono inevitabilmente. Per consentire a un'applicazione di superare i limiti dei periodi di indisponibilità di energia, soluzioni precedenti, è possibile salvare solo una parte della memoria del programma (evitando l'heap) limitando gli sviluppatori ad impiegare sofisticate tecniche di programmazione, o ricorrere a modifiche hardware sostituendo SRAM con FRAM, che potrebbe non solo avere un impatto sui costi ma anche sulla velocità di elaborazione. Questa tesi ha lo scopo di progettare tecniche software per dispositivi embedded a corrente transitoria, consentendo a un'applicazione di progredire, con una spesa minima possibile per salvare lo stato del sistema e senza ricorrere a modifiche hardware. Nella prima parte della tesi, presentiamo l'analisi dettagliata delle attuali soluzioni di energy harvesting e di trasferimento dell'energia wireless per le reti di sensori wireless (WSN). Definiamo proprietà desiderabili, classifichiamo soluzioni esistenti e discutiamo sulla loro applicabilità in diversi ambienti di distribuzione. Successivamente, conduciamo un'indagine completa sullo stato dell'arte per i sistemi embedded a corrente transitoria. Discutiamo le sfide, definiamo gli obiettivi e classifichiamo le soluzioni di sistemi embedded con alimentazione transitoria in diverse categorie in base alle tecniche che utilizzano per garantire il progresso della domanda. Nella seconda parte della tesi, sviluppiamo tre diverse tecniche per il salvataggio rapido dello stato del sistema e in modo efficiente dal punto di vista energetico, sfruttando diverse proprietà della memoria non volatile. La chiave della loro efficienza è il modo in cui le informazioni di stato sono organizzate sulla memoria non volatile. I nostri risultati, attraverso un'ampia valutazione, indicano in modo cruciale che non esiste una soluzione "taglia unica". Sono le caratteristiche della memoria dell'applicazione che renderanno preferibile una tecnica rispetto ad un'altra. Questi risultati di valutazione ci portano anche a progettare una tecnica addizionale, DICE, in cui, invece di leggere la memoria non volatile per calcolare i cambiamenti nella memoria principale (che è un'operazione che richiede energia e utilizzata nelle tecniche precedenti), tracciamo i cambiamenti nel memoria principale attraverso la sola strumentazione di codice. Ciò fa sì che DICE non solo riduca ulteriormente la quantità di dati da scrivere su memoria non volatile per garantire il progresso in avanti dell'applicazione, ma aiuta anche il supporto del sistema esistente a completare un determinato carico di lavoro con una migliore efficienza energetica e una minore latenza di esecuzione. Infine, presentiamo HarvOS che decide quando salvare lo stato del sistema osservando il peggiore costo energetico richiesto per raggiungere la prossima opportunità di salvare lo stato del sistema, a seconda della struttura del programma rappresentata nel grafico del flusso di controllo. HarvOS consente al sistema di prendere una decisione informata, ad ogni occasione per salvare lo stato del sistema, se continuare con la normale esecuzione o salvare lo stato del sistema. La nostra valutazione indica che HarvOS consente ai sistemi embedded con alimentazione transitoria di completare un determinato carico di lavoro con il 68% in meno di riavvii, rispetto alla letteratura esistente.Transiently powered embedded systems are becoming popular because of their self-sustainable, no maintenance and easily deployable nature. However, there is an intrinsic challenge with these systems: they can be unpredictably interrupted, as energy harvesting by no means can ensure a predictable supply of energy. Reboots will frequently happen, which translates into a waste of resources, including energy, as applications need to re-initialize and re-acquire the state. As a result, the overall performance inevitably suffers. To allow an application to cross the boundaries of periods of energy unavailability, prior solutions, either save only a portion of program memory (avoiding the heap) limiting developers to employ sophisticated programming techniques, or resort to hardware modifications by replacing SRAM with FRAM, that may not only impact cost but also processing speed. This thesis aims to design software techniques for transiently-powered embedded devices, allowing an application to make progress, with a minimum possible energy spent on saving the system state and without resorting to hardware modifications. In the first part of the thesis, we present the detailed analysis of the existing energy harvesting and wireless energy transfer solutions for wireless sensor networks (WSNs). We define desirable properties, classify existing solutions, and argue about their applicability in different deployment environments. Later, we conduct a comprehensive survey of the state of the art for transiently-powered embedded systems. We discuss challenges, define goals and classify transiently-powered embedded system solutions into different categories based on the techniques they use to ensure forward progress of the application. In the second part of the thesis, we develop three different techniques for saving system state quickly and in an energy-efficient manner, exploiting different properties of non-volatile memory. Key to their efficiency is the way the state information is organized on non-volatile memory. Our results, through extensive evaluation, crucially indicate that there is no "one-size-fits-all" solution. It is the application's memory characteristics that will make one technique preferable over another. These evaluation results also lead us to design an additional technique, DICE, in which, instead of reading non-volatile memory to compute changes in the main memory (which is energy-hungry operation and used in previous techniques), we track changes in the main memory through just code instrumentation. This makes DICE not only further reduce the amount of data to write onto non-volatile memory to ensure forward progress of the application, but also helps existing system support complete a given workload with better energy efficiency and reduced execution latency. Finally, we present HarvOS that decides when to save the system state by looking at the worst-case energy cost required to reach the next opportunity to save system state, depending on the program structure as represented in the control-flow graph. HarvOS allows the system to make an informed decision, at every opportunity to save system state, on whether to continue with the normal execution or save the system state. Our evaluation indicates that HarvOS allows transiently-powered embedded systems to complete a given workload with 68% fewer restarts, compared to existing literature.DIPARTIMENTO DI ELETTRONICA, INFORMAZIONE E BIOINGEGNERIAComputer Science and Engineering30BARESI, LUCIANOBONARINI, ANDRE

Ogbu and the debate on educational achievement: an exploration of the links between education, migration, identity and belonging

This paper looks at some of the issues raised by Ogbu’s work in relation to the education of different minority ethnic groups. Ogbu poses questions such as the value attached to education, its links to the future and its measurable outcomes in terms of ‘success’ as experienced by black participants. The desire for better life chances leads families to consider migration to a new country or resettlement within the same country, thus making migration both a local and a global phenomenon. As an example, attention is drawn to the situation facing South Asian children and their families in the UK. In terms of ethnicity and belonging, the wider question that is significant for many countries in the West after ‘Nine-Eleven’ is the education of Muslim children. A consideration of this current situation throws Ogbu’s identification of ‘autonomous minority’ into question. It is argued that a greater understanding of diverse needs has to be accompanied by a concerted effort to confront racism and intolerance in schools and in society, thus enabling all communities to make a useful contribution and to avoid the ‘risk’ of failure and disenchantment

CMS Search Plans and Sensitivity to New Physics using Dijets

CMS will use dijets to search for physics beyond the standard model during early LHC running. The inclusive jet cross section as a function of jet transverse momentum, with 10 pb$^{-1}$ of integrated luminosity, is sensitive to contact interactions beyond the reach of the Tevatron. The dijet mass distribution will be used to search for dijet resonances coming from new particles, for example an excited quark. Additional sensitivity to the existence of contact interactions or dijet resonances can be obtained by comparing dijet rates in two distinct pseudorapidity regions

Numerical study of radiative Maxwell viscoelastic magnetized flow from a stretching permeable sheet with the Cattaneo–Christov heat flux model

In this article, the Cattaneo-Christov heat flux model is implemented to study non-Fourier heat and mass transfer in the magnetohydrodynamic (MHD) flow of an upper convected Maxwell (UCM) fluid over a permeable stretching sheet under a transverse constant magnetic field. Thermal radiation and chemical reaction effects are also considered. The nonlinear partial differential conservation equations for mass, momentum, energy and species conservation are transformed with appropriate similarity variables into a system of coupled, highly nonlinear ordinary differential equations with appropriate boundary conditions. Numerical solutions have been presented for the influence of elasticity parameter (), magnetic parameter (M2), suction/injection parameter (λ), Prandtl number (Pr), conduction-radiation parameter (Rd), sheet stretching parameter (A), Schmidt number (Sc), chemical reaction parameter (γ_c), modified Deborah number with respect to relaxation time of heat flux (i.e. non-Fourier Deborah number) on velocity components, temperature and concentration profiles using the successive Taylor series linearization method (STSLM) utilizing Chebyshev interpolating polynomials and Gauss-Lobatto collocation. The effects of selected parameters on skin friction coefficient, Nusselt number and Sherwood number are also presented with the help of tables. Verification of the STSLM solutions is achieved with existing published results demonstrating close agreement. Further validation of skin friction coefficient, Nusselt number and Sherwood number values computed with STSLM is included using Mathematica software shooting quadrature

CMS search plans and sensitivity to new physics with dijets

CMS will use dijets to search for physics beyond the standard model during early LHC running. The inclusive jet cross section as a function of jet transverse momentum, with 10 inverse picobarns of integrated luminosity, is sensitive to contact interactions beyond the reach of the Tevatron. The dijet mass distribution will be used to search for dijet resonances coming from new particles, for example an excited quark. Additional sensitivity to the existence of contact interactions or dijet resonances can be obtained by comparing dijet rates in two distinct pseudorapidity regions.Comment: 10 pages, 4 figures, accepted for publication in J. Phys. G: Nucl. Part. Phy

Calorimetry Task Force Report

In this note we summarize the studies and recommendations of the calorimeter simulation task force (CaloTF). The CaloTF was established in February 2008 in order to understand and reconcile the discrepancies observed between the CMS calorimetry simulation and the test beam data recorded during 2004 and 2006. As the result of studies by the CaloTF a new version of Geant4 was developed and introduced in the CMS detector simulation leading to significanly better agreement with test beam data. Fast and flexible parameterizations describing showering in the calorimeter are introduced both in the Full Simulation (with a Gflash-like approach) and in the Fast Simulation. The CaloTF has developed a strategy to rapidly tune the CMS calorimeter simulation using the first LHC collision data when it becomes available. The improvements delivered by the CaloTF have been implemented in the software release CMSSW 2.1.0

Barriers for the Adoption of Professional Development Courses (PDCs) in Public Sector University Libraries

Objective: The purpose of the study was to explore the major problems of Library Professionals working in the academic libraries of public sector universities regarding participation in Professional Development Courses (PDCs). Methodology: Public sector Universities affiliated with Higher Education Commission (HEC) Pakistan, located in Lahore, Pakistan were the target population. The Census sampling technique was adopted to accomplish the objectives of the conducted study. 67 respondents participated in the study. A quantitative research technique was used in the study. A self-created questionnaire was used to collect the data. Key Findings: The findings of the study revealed that a good number of respondents were willing to participate in development activities. But, due to numerous hurdles included shortage of library staff, poor allocation of budget for development activities and non-interesting attitude of organizational administration towards the professional development of Library professionals were the major barriers towards professional development activities. Rationale and Significance: Past literature indicated that no study was conducted covering the objective of barriers in professional development. No researcher made the proper investigation in the local scenario. It was highly desired to explore the barriers in participating in professional development activities in the local context. Implication: This study would contribute to the professional literature. It will also assist policy makers to take initiatives for the capacity building of library professionals