Energy Optimization of Memory Intensive Parallel Workloads

Energy consumption is an important concern in modern multicore processors. The energy consumed by a multicore processor during the execution of an application can be minimized by tuning the hardware state utilizing knobs such as frequency, voltage etc. The existing theoretical work on energy minimization using Global DVFS (Dynamic Voltage and Frequency Scaling), despite being thorough, ignores the time and the energy consumed by the CPU on memory accesses and the dynamic energy consumed by the idle cores. This article presents an analytical energy-performance model for parallel workloads that accounts for the time and the energy consumed by the CPU chip on memory accesses in addition to the time and energy consumed by the CPU on CPU instructions. In addition, the model we present also accounts for the dynamic energy consumed by the idle cores. The existing work on global DVFS for parallel workloads shows that using a single frequency for the entire duration of a parallel application is not energy optimal and that varying the frequency according to the changes in the parallelism of the workload can save energy. We present an analytical framework around our energy-performance model to predict the operating frequencies (that depend upon the amount of parallelism) for global DVFS that minimize the overall CPU energy consumption. We show how the optimal frequencies in our model differ from the optimal frequencies in a model that does not account for memory accesses. We further show how the memory intensity of an application affects the optimal frequencies.

A Design & Feasibility Study of the Spaced Learning Programme

Objectives There is evidence from neuroscience, cognitive psychology and educational research that the delivery of a stimulus in a spaced format (over time) rather than a massed format (all at once) leads to more effective learning. This project aimed to pilot spaced learning materials using various spacing lengths for GCSE science by exploring the feasibility of introducing spaced leaning into regular classrooms and by evaluating teacher fidelity to the materials. The spaced learning methods will then be compared with traditional science revision techniques and a programme manual will be produced. Design A feasibility study. Methods A pilot study (4 schools) was carried out to examine the feasibility and teacher fidelity to the materials, using pupil workshops and teacher interviews. A subsequent random assignment experimental study (12 schools) will involve pre and post testing of students on a science attainment measure and a post-test implementation questionnaire. Results The literature review found that longer spacing intervals between repetitions of material (>24 hours) may be optimal for long term memory formation than shorter intervals. A logic model was developed to inform the design of various programme variants for the pilot and experimental study. This paper will report qualitative data from the initial pilot study. Conclusions The paper uses this research project as an example to explain the importance of conducting pilot work and small scale experimental studies to explore the feasibility and inform the design of educational interventions, rather than prematurely moving to RCT type studies.

Managed Acceleration for In-Memory Database Analytic Workloads

In-Memory Databases (IMDBs), such as SAP HANA, enable new levels of database performance by removing the disk bottleneck and by compressing data in memory. The consequence of this improved performance means that reports and analytic queries can now be processed on demand. Therefore, the goal is now to provide near real-time responses to compute and data intensive analytic queries. To facilitate this, much work has investigated the use of acceleration technologies within the database context. While current research into the application of these technologies has yielded positive results, they have tended to focus on single database tasks or on isolated single user requests. This paper uses SHEPARD, a framework for managing accelerated tasks across shared heterogeneous resources, to introduce acceleration into an IMDB. Results show how, using SHEPARD, multiple simultaneous user queries all receive speed-up by using a shared pool of accelerators. Results also show that offloading analytic tasks onto accelerators can have indirect benefits for other database workloads by reducing contention for CPU resources.

Does final demand for energy in Portugal exhibit long memory

In this paper, we measure the degree of fractional integration in final energy demand in Portugal using an ARFIMA model with and without adjustments for seasonality. We consider aggregate energy demand as well as final demand for petroleum, electricity, coal, and natural gas. Our findings suggest the presence of long memory in all of the energy demand variables, that the series are stationary, although the mean reversion process will be slower than in the typical short run processes. These results have important implications for the design of energy policies. The effects of temporary policy shocks on final energy demand will tend to disappear slowly. This means that even transitory shocks have long lasting effects. Given the temporary nature of these effects, however, permanent effects require permanent policies. This is unlike what would be suggested by the more standard but much more limited unit root approach, which would incorrectly indicate that even transitory policies would have permanent effects.

Present, imagination and memory in Zakes Mda and Mia Couto

Apesar de marcadas por contextos históricos e culturais distintos, é possível observar nas obras de dois dos autores mais significativos da África do Sul e de Moçambique, Zakes Mda e Mia Couto respectivamente, perspectivas semelhantes no que diz respeito à recuperação das memórias históricoculturais e à sua contribuição para a construção e compreensão das identidades pós-coloniais. Através da ficção, Zakes Mda e Mia Couto combinam a ligação da História a factos concretos com a necessidade de revelação associada à memória, criando assim espaços importantes para a discussão de algumas das mais complexas questões colocadas às identidades pós-coloniais. Para além dos contextos políticos, culturais e históricos que caracterizam e distinguem as literaturas sul-africana e moçambicana, tanto Zakes Mda como Mia Couto assumem nas suas obras a necessidade de analisar as identidades pós-coloniais contemporâneas dos dois países através da recuperação das suas memórias históricas.

O desafio da homogeneização normativa em instituições de memória: proposta de um modelo uniformizador e colaborativo

A informação digitalizada e nado digital, fruto do avanço tecnológico proporcionado pelas Tecnologias da Informação e Comunicação (TIC), bem como da filosofia participativa da Web 2.0, conduziu à necessidade de reflexão sobre a capacidade de os modelos atuais, para a organização e representação da informação, de responder às necessidades info-comunicacionais assim como o acesso à informação eletrónica pelos utilizadores em Instituições de Memória. O presente trabalho de investigação tem como objetivo a conceção e avaliação de um modelo genérico normativo e harmonizador para a organização e representação da informação eletrónica, num sistema de informação para o uso de utilizadores e profissionais da informação, no contexto atual colaborativo e participativo. A definição dos objetivos propostos teve por base o estudo e análise qualitativa das normas adotadas pelas instituições de memória, para os registos de autoridade, bibliográfico e formatos de representação. Após a concetualização, foi desenvolvido e avaliado o protótipo, essencialmente, pela análise qualitativa dos dados obtidos a partir de testes à recuperação da informação. A experiência decorreu num ambiente laboratorial onde foram realizados testes, entrevistas e inquéritos por questionário. A análise cruzada dos resultados, obtida pela triangulação dos dados recolhidos através das várias fontes, permitiu concluir que tanto os utilizadores como os profissionais da informação consideraram muito interessante a integração da harmonização normativa refletida nos vários módulos, a integração de serviços/ferramentas comunicacionais e a utilização da componente participativa/colaborativa da plataforma privilegiando a Wiki, seguida dos Comentários, Tags, Forum de discussão e E-mail.

The work of memory: embodiment, materiality and home in Jeanne Bouvier’s autobiographical writings

In this paper I follow trails in the memory of work by reading the books and papers of Jeanne Bouvier, a French seamstress, ardent trade-unionist and passionate writer, who left a rich body of labour literature including four published historical studies, as well as the memoirs of her life, work and struggles. Work, action and creativity are three interrelated planes on which Bouvier situates herself, while memory and imagination are interwoven in the way she seeks to understand herself in the world with others. What emerges as a particularly striking theme from Bouvier’s papers is a material matrix of mnemonic and imaginary practices, wherein bodies, places and objects are entangled in the narrative constitution of the self of the woman worker/writer.

A definition of literary literacy: a content analysis of literature syllabuses and interviews with Portuguese lecturers of literature

The aim of this paper is to present a definition of literary literacy in the context of majors in languages, literatures and cultures, in Portugal. A definition of literary literacy was deduced from a content analysis of primary data sources and from the theoretical underpinnings of the transactional theory of reading. The primary data sources are fourteen Portuguese and English literature syllabuses from four Portuguese universities (Lisboa, Nova, Coimbra and Porto) and twelve interviews with Portuguese university lecturers of literature. Based on the findings of a content analysis of both syllabuses and interviews, from the lecturers‘ point of view, a literary literate student doing a major in languages, literatures and cultures must, above all, be able to contextualize literary texts and their authors both historically and culturally, must be able to present an interpretation as a coherent text, and must be able to do and organize bibliographical research.

Electrical characterization of metal-oxide-polymer devices for non-volatile memory applications

The objective of this thesis is to study the properties of resistive switching effect based on bistable resistive memory which is fabricated in the form of Al2O3/polymer diodes and to contribute to the elucidation of resistive switching mechanisms. Resistive memories were characterized using a variety of electrical techniques, including current-voltage measurements, small-signal impedance, and electrical noise based techniques. All the measurements were carried out over a large temperature range. Fast voltage ramps were used to elucidate the dynamic response of the memory to rapid varying electric fields. The temperature dependence of the current provided insight into the role of trapped charges in resistive switching. The analysis of fast current fluctuations using electric noise techniques contributed to the elucidation of the kinetics involved in filament formation/rupture, the filament size and correspondent current capabilities. The results reported in this thesis provide insight into a number of issues namely: (i) The fundamental limitations on the speed of operation of a bi-layer resistive memory are the time and voltage dependences of the switch-on mechanism. (ii) The results explain the wide spread in switching times reported in the literature and the apparently anomalous behaviour of the high conductance state namely the disappearance of the negative differential resistance region at high voltage scan rates which is commonly attributed to a “dead time” phenomenon which had remained elusive since it was first reported in the ‘60s. (iii) Assuming that the current is filamentary, Comsol simulations were performed and used to explain the observed dynamic properties of the current-voltage characteristics. Furthermore, the simulations suggest that filaments can interact with each other. (iv) The current-voltage characteristics have been studied as a function of temperature. The findings indicate that creation and annihilation of filaments is controlled by filling and neutralizing traps localized at the oxide/polymer interface. (v) Resistive switching was also studied in small-molecule OLEDs. It was shown that the degradation that leads to a loss of light output during operation is caused by the presence of a resistive switching layer. A diagnostic tool that predicts premature failure of OLEDs was devised and proposed. Resistive switching is a property of oxides. These layers can grow in a number of devices including, organic light emitting diodes (OLEDs), spin-valve transistors and photovoltaic devices fabricated in different types of material. Under strong electric fields the oxides can undergo dielectric breakdown and become resistive switching layers. Resistive switching strongly modifies the charge injection causing a number of deleterious effects and eventually device failure. In this respect the findings in this thesis are relevant to understand reliability issues in devices across a very broad field.

Interaction between glucocorticoid and adenosine A2A receptors in the hippocampus : implications for learning and memory

Tese de doutoramento, Ciências Biomédicas (Neurociências), Universidade de Lisboa, Faculdade de Medicina, 2014

Cataloguing Kays: Body Image in the Catalogues of Kay & Co Ltd of Worcester, 1920 - 2000. JISC Final Report

Cataloguing Kays is a university-run project intended to create a community web-archive to celebrate the history and public memory of Kay & Co Ltd of Worcester, a noted mailorder catalogue company which was, until 2006, the largest employer in Worcester. The Kays Archive, housed at UoW, is one of the most comprehensive archive collections of 20th century mail-order catalogues in the UK and has a strong local elevance. The catalogues provide a window into over 100 years of body image, social history, consumable goods, fashion and design. The Project Team created www.WorldofKays.org, an online, fully-searchable archive containing 1500 digitised images from the catalogues, 1920-2000. The website is intended to form a seed bed for international research, focussing in particular on the representation of body image and the way the catalogues represent the developing tropes of consumer lifestyle and aspiration. The images are enhanced by blog postings from or film and audio interviews with local residents and former Kays staff members, who recall how the goods were selected and presented; as well as the impact the mail-order industry had on shaping 20th century lifestyle and consumption. These interviews and blogs have been sourced through the Cataloguing Kays team’s outreach activity in the local, academic and online communities. From the outset, we, the Cataloguing Kays team, engaged with online communities through social media sites, Facebook and Twitter, and through specialist blogs and online forums, inviting comment and contributions. Through events for the general public and a programme of targeted community outreach work with Kays Heritage Group and support groups for Worcestershire’s young and adult carers, we have also collected filmed and audio reminiscence material as well as community art and poetry content for the website. Our academic conference, the Catalogue of Dreams, showcased both the website and the physical archive to the wider academic, cultural and heritage sectors, provoking lively debateand much interest from international scholars.

A aprendizagem da noção de derivada no 11º ano

Relatório da prática de ensino supervisionada, Mestrado em Ensino da Matemática, Universidade de Lisboa, 2014

Our Past Betrays Us: Collective Memory, Homicide and Southern Lynching

Thesis (Master's)--University of Washington, 2013

'The Rich Harmonics of Past Time': Memory and Montage

This article examines John Sommerfield’s 1936 novel, May Day, a work that experiments with multiple perspectives, voices and modes. The article examines the formal experiments of the novel in order to bring into focus contemporary debates around the aesthetics of socialist realism, the politics of Popular Front anti-fascism and the relationship between writers on the left and the legacies of literary modernism. The article suggests that while leftist writers’ appropriations of modernist techniques have been noted by critics, there has been a tendency to assume that such approaches were in contravention of the aesthetics of socialist realism. Socialist realism is shown to be more a fluid and disputed concept than such readings suppose, and Sommerfield’s adaptations of modernist textual strategies are interpreted as key components of a political aesthetic directed towards the problems of alienation and social fragmentation.