Accelerator Memory Reuse in the Dark Silicon Era

Accelerators integrated on-die with General-Purpose CPUs (GP-CPUs) can yield significant performance and power improvements. Their extensive use, however, is ultimately limited by their area overhead; due to their high degree of specialization, the opportunity cost of investing die real estate on accelerators can become prohibitive, especially for general-purpose architectures. In this paper we present a novel technique aimed at mitigating this opportunity cost by allowing GP-CPU cores to reuse accelerator memory as a non-uniform cache architecture (NUCA) substrate. On a system with a last level-2 cache of 128kB, our technique achieves on average a 25% performance improvement when reusing four 512 kB accelerator memory blocks to form a level-3 cache. Making these blocks reusable as NUCA slices incurs on average in a 1.89% area overhead with respect to equally-sized ad hoc cache slice

Efeito da colheita mecanizada e da secagem artificial sobre a capacidade de expansão de milho-pipoca.

Neste trabalho foram estudados o efeito da colheita mecanica, variando-se a velocidade do cilindro debulhador e colhedora e o teor de umidade dos graos, assim como o efeito da temperatura do ar de secagem artificial sobre a capacidade de expansao de milho-pipoca. Dois cultivares de milho pipoca, Zelia e CMS 43, foram colhidos e debulhados manualmente, e mecanicamente com tres diferentes rotacoes do cilindro debulhador 500, 600 e 700 rpm. O produto foi submetido ao processo de secagem em camada fina ate atingir o teor de umidade de 12+/- 1% b.u., com o ar a temperatura ambiente em torno de 23 oC, e a altas temperaturas de 40, 50 e 60 oC, mantendo fluxo de ar constante de 1 m.s-1. Depois da secagem, foi realizado o teste-padrao de qualidade, teste da capacidade de expansao, utilizando-se um pipocador eletrico com temperatura de resistencia de 280oC, durante 4 min, para uma amostra de 30ml. A capacidade de expansao foi expressa pela relacao do volume de pipoca expandida pelo volume de graos de milho-pipoca. De acordo com os resultados obtidos, concluiu-se que a colheita mecanica e a secagem e altas temperaturas sao prejudiciais a capacidade de expansao do grao. O teor de umidade inicial de colheita de 15 +/- 1% b.u. resultou em menores porcentagens de perda da capacidade de expansao, quando comparado ao teor de umidade de 19 +/- 1% b.u. Quanto a secagem artificial, observou-se que o aumento de temperatura do ar provoca a diminuicao da capacidade de expansao do milho-pipoca, em ambos os cultivares. Pode-se afirmar, ainda, que o milho pipoca do cultivar Zelia apresentou os melhores resultados de capacidade de expansao, para todos os tratamentos, quando comparado ao cultivar CMS 43, o que provavelmente ocorreu em virtude de suas caracteristicas geneticas que lhe conferem maior susceptibilidade aos danos, relativamente ao primeiro cultivar

Compact steep-spectrum sources from the S4 sample

We present the results of 5-GHz observations with the VLA A-array of a sample of candidate Compact Steep Spectrum sources (CSSs) selected from the S4 survey. We also estimate the symmetry parameters of high-luminosity CSSs selected from different samples of radio sources, and compare these with the larger sources of similar luminosity to understand their evolution and the consistency of the CSSs with the unified scheme for radio galaxies and quasars. The majority of CSSs are likely to be young sources advancing outwards through a dense asymmetric environment. The radio properties of CSSs are found to be consistent with the unified scheme, in which the axes of the quasars are observed close to the line of sight, while radio galaxies are observed close to the plane of the sky.Comment: accepted for publication in mnras; 8 pages, figure 1 with 21 images, and two additional figures; 2 table

The role of virtual reality in built environment education

This study builds upon previous research on the integration of Virtual Reality (VR) within the built environment curriculum and aims to investigate the role of VR and three-dimensional (3D) computer modelling on learning and teaching in a school of the built environment. In order to achieve this aim, a number of academic experiences were analysed to explore the applicability and viability of 3D computer modelling and VR into built environment subject areas. Although two-dimensional (2D) representations have been greatly accepted by built environment professions and education, 3D computer representations and VR applications, offering interactivity and immersiveness, are not yet widely accepted. The study attempts to understand the values and challenges of integrating visualisation technologies into built environment teaching and investigates tutors’ perceptions, opinions and concerns with respect to these technologies. The study reports on the integration process and considers how 3D computer modelling and VR technologies can combine with, and extend, the existing range of learning and teaching methods appropriate to different disciplines and programme areas

Measurement errors and tax evasion in annual incomes: evidence from survey data matched with fiscal data

Individual records, referred to personal interviews of a survey on income carried out in Modena during 2012 and tax year 2011, had been matched with their corresponding records in the Ministry of Finance databases containing the fiscal incomes of tax year 2011. The analysis of the resulting data set suggested that the fiscal income was generally more reliable than surveyed income, but in the literature the exact opposite is often assumed. Moreover, the obtained data set enables identification of the factors determining over- and under-reporting, as well as measurement error, through a comparison of the surveyed income with the fiscal income, only for suitable categories of interviewees: the taxpayers who are obliged to respect the law (the constrained sector), and taxpayers who have many possibilities to evade (the unconstrained sector). The percentage of under-reporters (67.3%) was higher than those of over-reporters (32.7%). Level of income, age, and education were the main regressors affecting the measurement errors and the behaviours of taxpayers. Estimations of tax evasion and the impacts of personal factors affecting it were carried out following different approaches. The average of individual propensity to tax evasion was 25.93% of the corresponding fiscal income. The potential total tax evaders were about 10%

Non-specific cytotoxicity of spleen cells in mice bearing transplanted chemically induced fibrosarcomas.

Spleen cells collected from mice bearing transplanted chemically induced syngeneic fibrosarcomas non-specifically inhibited DNA synthesis of sarcoma and lymphoma target cells in vitro. Splenocytes from mice hyper-immunized against a syngeneic sarcoma specifically inhibited DNA synthesis of the tumour used for immunization. The impairment of tumour-cell DNA synthesis was associated in vitro with cytostasis, and lysis of the target cells was not seen. Since treatment with anti-theta serum and complement did not impair cytostatic action of the spleen cells, and since thymus-deprived animals showed similar activity to normal mice, T lymphocytes were not involved in non-specific cytostasis. Removal of phagocytic adherent cells by carbonyl iron markedly inhibited the cytostatic activity of the spleen cells, suggesting a role in this reaction for cells of the monocyte-macrophage series. The presence of an actively growing sarcoma was a prerequisite for the expression of non-specific cytostasis, since surgical excision resulted in complete disappearance of this activity of spleen cells