Distributed learning of CNNs on heterogeneous CPU/GPU architectures

Convolutional Neural Networks (CNNs) have shown to be powerful classification tools in tasks that range from check reading to medical diagnosis, reaching close to human perception, and in some cases surpassing it. However, the problems to solve are becoming larger and more complex, which translates to larger CNNs, leading to longer training times that not even the adoption of Graphics Processing Units (GPUs) could keep up to. This problem is partially solved by using more processing units and distributed training methods that are offered by several frameworks dedicated to neural network training. However, these techniques do not take full advantage of the possible parallelization offered by CNNs and the cooperative use of heterogeneous devices with different processing capabilities, clock speeds, memory size, among others. This paper presents a new method for the parallel training of CNNs that can be considered as a particular instantiation of model parallelism, where only the convolutional layer is distributed. In fact, the convolutions processed during training (forward and backward propagation included) represent from $60$-$90$\% of global processing time. The paper analyzes the influence of network size, bandwidth, batch size, number of devices, including their processing capabilities, and other parameters. Results show that this technique is capable of diminishing the training time without affecting the classification performance for both CPUs and GPUs. For the CIFAR-10 dataset, using a CNN with two convolutional layers, and $500$ and $1500$ kernels, respectively, best speedups achieve $3.28\times$ using four CPUs and $2.45\times$ with three GPUs. Modern imaging datasets, larger and more complex than CIFAR-10 will certainly require more than $60$-$90$\% of processing time calculating convolutions, and speedups will tend to increase accordingly

Thickness of the buccal bone wall and root angulation in the maxilla and mandible: an approach to cone beam computed tomography

Background: The objective of this paper is to anatomically describe the bone morphology in the maxillary and mandibular tooth areas, which might help in planning post-extraction implants. Methods: CBCT images (Planmeca ProMax 3D) of 403 teeth (208 upper teeth and 195 lower teeth) were obtained from 49 patients referred to the Dental School of Seville from January to December 2014. The thickness of the facial wall was measured at the crest, point A, 4mm below, point B, and at the apex, point C. The second parameter was the angle formed between the dental axis and the axis of the basal bone. Results: A total of 403 teeth were measured. In the maxilla, 89.4% of incisors, 93.94% of canines, 78% of premolars and 70.5% of molars had a buccal bone wall thickness less than the ideal 2mm. In the mandible, 73.5% of incisors, 49% of canines, 64% of premolars and 53% of molars had <1mm buccal bone thickness as measured at point B. The mean angulation in the maxilla was 11.67±6.37° for incisors, 16.88±7.93° for canines, 13.93±8.6° for premolars, and 9.89±4.8° for molars. In the mandible, the mean values were 10.63±8.76° for incisors, 10.98±7.36° for canines, 10.54±5.82° for premolars and 16.19±11.22° for molars. Conclusions: The high incidence of a buccal wall thickness of less than 2mm in over 80% of the assessed sites indicates the need for additional regeneration procedures, and several locations may also require custom abutments to solve the angulation problems for screw-retained crowns

Interdisciplinary Discussions about the Conservation of Software-Based Art.

In 2015/16 Tate organised a series of virtual discussions related to the preservation of softwarebased art as part of Tate’s partnership in PERICLES, a European‐funded project which focuses on the long‐term digital conservation and preservation of digital resources, with particular focus on actively managing change and risk as part of this process. The idea for this series arose from the realisation that managing technical change in software‐based art is not only a common concern for practitioners working in the field but also of interest to the research community. A group of engaged expert practitioners and researchers were invited to consider a set of topics at the core of the conservation of software‐based artworks. Six discussion sessions were organised over a period of one year. This report summarises the outcomes of these meetings and examines some of the key points

EVALUATION OF THE EFFECTS OF ILLUMINATION, TEMPERATURE AND PAINTING FINISH IN PSP TECHNIQUE

This paper reports the results of global pressure measurements on a NACA0012 profile, obtained with the Pressure Sensitive Paint technique (PSP), and compares them with conventional pressure tap measurements with the purpose of analyzing the influence of parameters as illumination efficiency and temperature variation of the air flow in the accuracy of the PSP experimental results. The experimental measurements were conducted in the Pilot Transonic Wind Tunnel (TTP) of the Instituto de Aeronáutica e Espaço (IAE) for Mach number values of 0.4, 0.6 and 0.8. The experiments showed that in a carefully prepared experiment, under appropriated operational conditions, and rigorous adjustments of the PSP components, the obtained results can be accurate. Moreover, even when the influence of temperature is significant and the illumination condition is not ideal, it was possible to estimate well the impact caused in the pressure distribution over the model surface

Allocation of periodic tasks with precedences on transputer-based systems

Task allocation is an important component of the process of mapping modules of application programs to multicomputers. A scheme for static allocation of periodic tasks with precedences to processors is developed considering task execution times, communication costs, and utilization level of each processor. It has the main goal of minimizing the application response time with a minimum number of processors. A network of transputers is employed as a platform to experimentally evaluate the allocation approach constructed with this work. An existing communication layer in the language ADA is improved to provide an efficient support for task flow simulations on transputer networks. The first phase of the allocation scheme is a constructive assignment heuristic that allocates the cluster of tasks composed of all tasks in the critical path in the same processor. The remaining tasks are allocated according to a heuristic function that considers task precedences, task execution times, and relative sizes of intertask messages. The initial allocation is improved in the second phase by using an iterative pairwise interchange of tasks that considers interprocessor communication distances. The overall scheme of task allocation was successfully tested and analyzed through simulation of several applications on a transputer network providing a near optimal solution.http://archive.org/details/allocationofperi00falcLieutenant Commander, Brazilian NavyApproved for public release; distribution is unlimited

PDS ‘To Go’? ‘Portability’ of Rights through Real-time Monitoring: the Centralised Online Real-time Electronic PDS in Chhattisgarh, India

Information and communications technology (ICT)-based reforms are increasingly being used to improve the delivery of public services. These reforms have taken the form of crowd-sourcing information (election monitoring), using ICTs to increase efficiency (e.g. computerised land registry systems), and connecting users to providers (e.g. mobile phone-based health services). These different approaches attempt to improve delivery through either (a) improving the quality of information, (b) reducing corruption or (c) making access more convenient and simple. The main question which the research reported here addressed was: through what processes, and under what conditions, do real-time monitoring technology-based reforms strengthen accountability and affect the delivery of public services? This was done by examining the Centralised Online Real-time Electronic (CORE) Public Distribution System (PDS) reforms introduced by the State Government of Chhattisgarh, India.UK Department for International Developmen

Deep Chandra Observations of NGC 5728: Morphology and Spectral Properties of the Extended X-ray Emission

Recent deep Chandra observations of nearby Compton thick (CT) AGN have produced surprising results, uncovering extended emission not only in the soft X-rays but in the hard emission (>3 keV), challenging the long-held belief that the characteristic hard X-ray continuum and fluorescent Fe Ka lines are associated with the torus in the standard picture of AGN. In this work, we present the analysis of our deep (~261 ks) X-ray Chandra ACIS-S observations of NGC 5728, a nearby (z=0.00932) CT AGN. We find that the diffuse emission is more extended at lower energies, in the bicone direction out to ~2 kpc radially, but also significantly extended in the direction of the cross-cone, out to ~1.4 kpc. Our results suggest that the ratio of detected photons in the cross-cone to the bicone region is ~16%, below 3 keV, decreasing to 5% for energies 3-6 keV. The nuclear spectrum suggests a low photoionization phase mixed with a more ionized gas component, while the bicone and cross-cone spectra are dominated by a mix of photoionization and shocked gas emission. A mixture of thermal and photoionization models to fit the spectra indicates the presence of complex gas interactions, consistent with previous observations of other CT AGN (e.g., ESO 428-G014)

The path from the choroid plexus to the subventricular zone: go with the flow!

In adult mammals, under physiological conditions, neurogenesis, the process of generating new functional neurons from precursor cells, occurs mainly in two brain areas: the subgranular zone in the dentate gyrus of the hippocampus, and the subventricular zone (SVZ) lining the walls of the brain lateral ventricles. Taking into account the location of the SVZ and the cytoarchitecture of this periventricular neural progenitor cell niche, namely the fact that the slow dividing primary progenitor cells (type B cells) of the SVZ extend an apical primary cilium toward the brain ventricular space which is filled with cerebrospinal fluid (CSF), it becomes likely that the composition of the CSF can modulate both self-renewal, proliferation and differentiation of SVZ neural stem cells. The major site of CSF synthesis is the choroid plexus (CP); quite surprisingly, however, it is still largely unknown the contribution of molecules specifically secreted by the adult CP as modulators of the SVZ adult neurogenesis. This is even more relevant in light of recent evidence showing the ability of the CP to adapt its transcriptome and secretome to various physiologic and pathologic stimuli. By giving particular emphasizes to growth factors and axonal guidance molecules we will illustrate how CP-born molecules might play an important role in the SVZ niche cell population dynamics.Ana M. Falcão and Ashley Novais are recipients of Ph.D.Fellowships from the Fundação para a Ciência e Tecnologia (FCT,Portugal).Fernanda Marques is a recipiente of post docToral fellowship from the Fundação para a Ciência e Tecnologia (FCT,Portugal).This work is supported by a grant from FCT (PTDC/SAU-OSM/104475/2008