Performance analysis of single board computer clusters

The past few years have seen significant developments in Single Board Computer (SBC) hardware capabilities. These advances in SBCs translate directly into improvements in SBC clusters. In 2018 an individual SBC has more than four times the performance of a 64-node SBC cluster from 2013. This increase in performance has been accompanied by increases in energy efficiency (GFLOPS/W) and value for money (GFLOPS/$). We present systematic analysis of these metrics for three different SBC clusters composed of Raspberry Pi 3 Model B, Raspberry Pi 3 Model B+ and Odroid C2 nodes respectively. A 16-node SBC cluster can achieve up to 60GFLOPS, running at 80W. We believe that these improvements open new computational opportunities, whether this derives from a decrease in the physical volume required to provide a fixed amount of computation power for a portable cluster; or the amount of compute power that can be installed given a fixed budget in expendable compute scenarios. We also present a new SBC cluster construction form factor named Pi Stack; this has been designed to support edge compute applications rather than the educational use-cases favoured by previous methods. The improvements in SBC cluster performance and construction techniques mean that these SBC clusters are realising their potential as valuable developmental edge compute devices rather than just educational curiosities

An investigation into the depth of penetration of low level laser therapy through the equine tendon in vivo

Low level laser therapy (LLLT) is frequently used in the treatment of wounds, soft tissue injury and in pain management. The exact penetration depth of LLLT in human tissue remains unspecified. Similar uncertainty regarding penetration depth arises in treating animals. This study was designed to test the hypothesis that transmission of LLLT in horses is increased by clipping the hair and/or by cleaning the area to be treated with alcohol, but is unaffected by coat colour. A LLLT probe (810 nm, 500 mW) was applied to the medial aspect of the superficial flexor tendon of seventeen equine forelimbs in vivo. A light sensor was applied to the lateral aspect, directly opposite the laser probe to measure the amount of light transmitted. Light transmission was not affected by individual horse, coat colour or leg. However, it was associated with leg condition (F = 4.42, p = 0.0032). Tendons clipped dry and clipped and cleaned with alcohol, were both associated with greater transmission of light than the unprepared state. Use of alcohol without clipping was not associated with an increase in light transmission. These results suggest that, when applying laser to a subcutaneous structure in the horse, the area should be clipped and cleaned beforehand

Commodity single board computer clusters and their applications

© 2018 Current commodity Single Board Computers (SBCs) are sufficiently powerful to run mainstream operating systems and workloads. Many of these boards may be linked together, to create small, low-cost clusters that replicate some features of large data center clusters. The Raspberry Pi Foundation produces a series of SBCs with a price/performance ratio that makes SBC clusters viable, perhaps even expendable. These clusters are an enabler for Edge/Fog Compute, where processing is pushed out towards data sources, reducing bandwidth requirements and decentralizing the architecture. In this paper we investigate use cases driving the growth of SBC clusters, we examine the trends in future hardware developments, and discuss the potential of SBC clusters as a disruptive technology. Compared to traditional clusters, SBC clusters have a reduced footprint, are low-cost, and have low power requirements. This enables different models of deployment—particularly outside traditional data center environments. We discuss the applicability of existing software and management infrastructure to support exotic deployment scenarios and anticipate the next generation of SBC. We conclude that the SBC cluster is a new and distinct computational deployment paradigm, which is applicable to a wider range of scenarios than current clusters. It facilitates Internet of Things and Smart City systems and is potentially a game changer in pushing application logic out towards the network edge.EPSR

Uso do laser arseneto de gálio (904nm) após excisão artroplástica da cabeça do fêmur em cães Use of low-power gallium arsenide laser (904nm) after arthroplasty excision of the femoral head in dogs

OBJETIVO: Avaliar a ação do laser diodo Arseneto de Gálio na evolução pós-operatória de cães submetidos à excisão artroplástica da cabeça e colo do fêmur. MÉTODOS: Treze cães portadores de Legg-Calvé-Perthes Disease ou Necrose Asséptica da Cabeça do Fêmur (NACF) foram divididos em dois grupos: (I) sete cães que não foram irradiados - grupo controle; (II) seis cães irradiados uma vez ao dia durante cinco dias consecutivos com o laser Arseneto de Gálio (904nm), densidade de energia 4J/cm2 e tempo de exposição automaticamente ajustado pelo aparelho. Para a avaliação da evolução pós-operatória preencheu-se protocolo com graduação da dor de apoio do membro operado. Utilizou-se teste estatístico não paramétrico U de Mann-Whitney para análise dos resultados. RESULTADOS: O grupo I iniciou o apoio do membro com uma média de 12 dias de pós-operatório e o grupo II com uma média de quatro dias de pós-operatório, sendo estatisticamente significante (p=0.0012). CONCLUSÃO: A irradiação com o laser de baixa potência Arseneto de Gálio (904nm) na dose 4J/cm2, periarticular, promoveu rápido retorno da função do membro em cães após a excisão artroplástica da cabeça do fêmur, otimizando a recuperação pós-operatória.<br>PURPOSE: Evaluate the action of the Gallium Arsenide semiconductor laser in the post-operative evolution in dogs after the femoral head and neck artroplastic excision. METHODS: Thirteen dogs bearing Legg-Calvé-Perthes Disease were divided into two groups: (I) 7 non-radiated dogs - control group; (II) 6 dogs irradiated once a day for 5 consecutive days with the Galium Arsenide laser (904nm), energy density 4J/cm² and exposition time automatically adjusted by the device. In order to evaluate the post-operative evolution it was needed to fill a report stating the degree of the pain as well as the weight bearing of the affected limb. A U non-parametric statistics test of Mann-Whitney was used to perform the results analysis. RESULTS: Group I started the weight-bearing limb by means of an average of 12 post-operative days; group II started it by 4 post-operative days. The U non-parametric statistics test of Mann-Whitney was statistically significant between groups (p=0.0012). CONCLUSION: The approach suggests that the irradiation of the periarticular tissues using the low power Galium Arsenide laser provides a faster weight-bearing limb recovery in dogs after the femoral head and neck artroplastic excision

Acknowledgement to reviewers of Informatics in 2018

Rigorous peer-review is the corner-stone of high-quality academic publishing. The editorial team greatly appreciates the reviewers who contributed their knowledge and expertise to the journal’s editorial process over the past 12 months. In 2018, a total of 43 papers were published in the journal, with a median time to first decision of 24 days and a median time to publication of 68 days