A Hybrid Parallel Algorithm for Computing and Tracking Level Set Topology

The contour tree is a topological abstraction of a scalar field that captures evolution in level set connectivity. It is an effective representation for visual exploration and analysis of scientific data. We describe a work-efficient, output sensitive, and scalable parallel algorithm for computing the contour tree of a scalar field defined on a domain that is represented using either an unstructured mesh or a structured grid. A hybrid implementation of the algorithm using the GPU and multi-core CPU can compute the contour tree of an input containing 16 million vertices in less than ten seconds with a speedup factor of upto 13. Experiments based on an implementation in a multi-core CPU environment show near-linear speedup for large data sets.

The effect of cell size and channel density on neuronal information encoding and energy efficiency

Identifying the determinants of neuronal energy consumption and their relationship to information coding is critical to understanding neuronal function and evolution. Three of the main determinants are cell size, ion channel density, and stimulus statistics. Here we investigate their impact on neuronal energy consumption and information coding by comparing single-compartment spiking neuron models of different sizes with different densities of stochastic voltage-gated Na+ and K+ channels and different statistics of synaptic inputs. The largest compartments have the highest information rates but the lowest energy efficiency for a given voltage-gated ion channel density, and the highest signaling efficiency (bits spike(-1)) for a given firing rate. For a given cell size, our models revealed that the ion channel density that maximizes energy efficiency is lower than that maximizing information rate. Low rates of small synaptic inputs improve energy efficiency but the highest information rates occur with higher rates and larger inputs. These relationships produce a Law of Diminishing Returns that penalizes costly excess information coding capacity, promoting the reduction of cell size, channel density, and input stimuli to the minimum possible, suggesting that the trade-off between energy and information has influenced all aspects of neuronal anatomy and physiology.

Consequences of Converting Graded to Action Potentials upon Neural Information Coding and Energy Efficiency

Information is encoded in neural circuits using both graded and action potentials, converting between them within single neurons and successive processing layers. This conversion is accompanied by information loss and a drop in energy efficiency. We investigate the biophysical causes of this loss of information and efficiency by comparing spiking neuron models, containing stochastic voltage-gated Na+ and K+ channels, with generator potential and graded potential models lacking voltage-gated Na+ channels. We identify three causes of information loss in the generator potential that are the by-product of action potential generation: (1) the voltage-gated Na+ channels necessary for action potential generation increase intrinsic noise and (2) introduce non-linearities, and (3) the finite duration of the action potential creates a `footprint' in the generator potential that obscures incoming signals. These three processes reduce information rates by similar to 50% in generator potentials, to similar to 3 times that of spike trains. Both generator potentials and graded potentials consume almost an order of magnitude less energy per second than spike trains. Because of the lower information rates of generator potentials they are substantially less energy efficient than graded potentials. However, both are an order of magnitude more efficient than spike trains due to the higher energy costs and low information content of spikes, emphasizing that there is a two-fold cost of converting analogue to digital; information loss and cost inflation.

Emergency Handling in MICS based Body Area Network

Body Area Network, a new wireless networking paradigm, promises to revolutionize the healthcare applications. A number of tiny sensor nodes are strategically placed in and around the human body to obtain physiological information. The sensor nodes are connected to a coordinator or a data collector to form a Body Area Network. The tiny devices may sense physiological parameters of emergency in nature (e.g. abnormality in heart bit rate, increase of glucose level above the threshold etc.) that needs immediate attention of a physician. Due to ultra low power requirement of wireless body area network, most of the time, the coordinator and devices are expected to be in the dormant mode, categorically when network is not operational. This leads to an open question, how to handle and meet the QoS requirement of emergency data when network is not operational? Emergency handling becomes more challenging at the MAC layer, if the channel access related information is unknown to the device with emergency message. The aforementioned scenarios are very likely scenarios in a MICS (Medical Implant Communication Service, 402-405 MHz) based healthcare systems. This paper proposes a mechanism for timely and reliable transfer of emergency data in a MICS based Body Area Network. We validate our protocol design with simulation in a C++ framework. Our simulation results show that more than 99 p ercentage of the time emergency messages are reached at the coordinator with a delay of 400ms.

Crowd Flow Segmentation based on Motion Vectors in H.264 Compressed Domain

In this work, we have explored the prospect of segmenting crowd flow in H. 264 compressed videos by merely using motion vectors. The motion vectors are extracted by partially decoding the corresponding video sequence in the H. 264 compressed domain. The region of interest ie., crowd flow region is extracted and the motion vectors that spans the region of interest is preprocessed and a collective representation of the motion vectors for the entire video is obtained. The obtained motion vectors for the corresponding video is then clustered by using EM algorithm. Finally, the clusters which converges to a single flow are merged together based on the bhattacharya distance measure between the histogram of the of the orientation of the motion vectors at the boundaries of the clusters. We had implemented our proposed approach on the complex crowd flow dataset provided by 1] and compared our results by using Jaccard measure. Since we are performing crowd flow segmentation in the compressed domain using only motion vectors, our proposed approach performs much faster compared to other pixel domain counterparts still retaining better accuracy.

Information legislation and management survey 2014

The 10th annual Jisc, GuildHE and Universities UK information legislation and management survey shows a rise in the number of Freedom of Information (FOI) requests for the tenth consecutive year. In contrast Environmental Information Regulations (EIR) requests appear to have levelled off to a fairly consistent rate, while Data Protection Act (DPA) requests have declined back to levels last seen in 2008. The average monthly number of FOI requests received by UK universities has risen by 19% since 2013 and by almost seven times over the last decade since our survey began. The average across the 46 participating institutions was 219 FOI requests with the highest of 454 reported by one participant.

Information legislation and management survey 2014

The 10th annual Jisc, GuildHE and Universities UK information legislation and management survey shows a rise in the number of Freedom of Information (FOI) requests for the tenth consecutive year. In contrast Environmental Information Regulations (EIR) requests appear to have levelled off to a fairly consistent rate, while Data Protection Act (DPA) requests have declined back to levels last seen in 2008. The average monthly number of FOI requests received by UK universities has risen by 19% since 2013 and by almost seven times over the last decade since our survey began. The average across the 47 participating institutions was 218 FOI requests with the highest of 454 reported by one participant.

Information processing and higher psychological functions in the disconnected hemispheres of human commissurotomy patients

Several patients of P. J. Vogel who had undergone cerebral commissurotomy for the control of intractable epilepsy were tested on a variety of tasks to measure aspects of cerebral organization concerned with lateralization in hemispheric function. From tests involving identification of shapes it was inferred that in the absence of the neocortical commissures, the left hemisphere still has access to certain types of information from the ipsilateral field. The major hemisphere can still make crude differentiations between various left-field stimuli, but is unable to specify exact stimulus properties. Most of the time the major hemisphere, having access to some ipsilateral stimuli, dominated the minor hemisphere in control of the body.

Competition for control of the body between the hemispheres is seen most clearly in tests of minor hemisphere language competency, in which it was determined that though the minor hemisphere does possess some minimal ability to express language, the major hemisphere prevented its expression much of the time. The right hemisphere was superior to the left in tests of perceptual visualization, and the two hemispheres appeared to use different strategies in attempting to solve the problems, namely, analysis for the left hemisphere and synthesis for the right hemisphere.

Analysis of the patients' verbal and performance I.Q.'s, as well as observations made throughout testing, suggest that the corpus callosum plays a critical role in activities that involve functions in which the minor hemisphere normally excels, that the motor expression of these functions may normally come through the major hemisphere by way of the corpus callosum.

Lateral specialization is thought to be an evolutionary adaptation which overcame problems of a functional antagonism between the abilities normally associated with the two hemispheres. The tests of perception suggested that this function lateralized into the mute hemisphere because of an active counteraction by language. This latter idea was confirmed by the finding that left-handers, in whom there is likely to be bilateral language centers, are greatly deficient on tests of perception.

Information science and the scientist. A look at information requirements and the technologies available to scientists in the pursuit of information

A review article looking at the type of information requirements commonly shared by scientists and their use of traditional information services. Areas covered include primary requirements of IFE (Institute of Freshwater Ecology) staff, pure versus applied research, informal and personal sources of information, and traditional library and information services. It goes on to describe how research into information systems and technology may improve the wider accessibility and use of information to the scientific community. Technologies covered include online databases, telecommunications, gateways, expert systems, optical technology and applications of CDROM.

Os gêneros digitais no livro didático de língua portuguesa

Este trabalho de pesquisa tem dois objetivos principais: o primeiro diz respeito a avaliar, em livros didáticos, indicados pelos professores do Estado do Piauí, Teresina, a abordagem proposta neles acerca dos gêneros digitais, tendo em vista a grande disseminação da tecnologia da informação e comunicação nas últimas décadas. Para tanto, propõe-se um acurado levantamento dos livros didáticos, do 6 ao 9 ano, verificando a incidência de gêneros discursivos digitais e não digitais nos diferentes livros analisados. Buscou-se entender os critérios de como são apresentados, bem como o tratamento dado ao gênero, cotejando a forma de abordagem proposta para os gêneros denominados digitais a outros gêneros predominantes na abordagem dos diferentes livros. Das quatro coleções analisadas, percebeu-se uma abordagem mais formalizada não só do ponto de vista da estrutura, mas também do ponto de vista dos recursos linguísticos que compõem os diferentes gêneros não digitais. Em contrapartida, pôde-se verificar uma incidência muito restrita de abordagem dos gêneros digitais. Os resultados nos levam a postular que esses são pouco frequentes nos livros didáticos mais adotados no estado e, quando são apresentados, há uma abordagem voltada somente para a sua estrutura, de forma metalinguística, sem preocupação com o uso social dos recursos utilizados nos gêneros digitais. Tal perspectiva nos levou ao segundo objetivo: propor a apresentação de uma sequência didática, cujo gênero central são os gêneros digitais, atendendo às habilidades e competências 1 e 9 do ENEM Exame Nacional do Ensino Médio. Neste sentido essas competências e habilidades visam a identificar as diferentes linguagens veiculadas na mídia; conhecer e dominar os recursos expressivos como caracterizadores dos sistemas de comunicação e informação, além de reconhecer a função social da linguagem, como também o impacto das ferramentas tecnológicas na vida pessoal e profissional. Estas habilidades e competências usam os dois pilares fundamentais: a função social do gênero e a aplicação do seu uso. A proposta apresentada baseia-se em uma concepção sóciohistórica de língua, considerando a importância de uma conscientização dos cidadãos, jovens em idade escolar, da importância social dos recursos tecnológicos, bem como a necessidade de ampliação do uso em uma sociedade multissemiótica