Time filter

Source Type

Shen L.,Shanghai University | Zhang Z.,Shanghai University | Liu Z.,Shanghai University | Liu Z.,Campus University Of Beaulieu
IEEE Transactions on Circuits and Systems for Video Technology | Year: 2014

High Efficiency Video Coding (HEVC) adopts the quadtree structured coding unit (CU), which allows recursive splitting into four equally sized blocks. At each depth level, it enables SKIP mode, merge mode, inter 2N × 2 N, inter 2N × N, inter N × 2 N, inter 2N × nU, inter 2N × nD, inter nL × N, inter nR × N, inter N × N (only available for the smallest CU), intra 2N × N, and intra N × N (only available for the smallest CU) in inter-frames. Similar to H.264/AVC, the mode decision process in HEVC is performed using all the possible depth levels (or CU sizes) and prediction modes to find the one with the least rate distortion (RD) cost using Lagrange multiplier. This achieves the highest coding efficiency, but leads to a very high computational complexity. Since the optimal prediction mode is highly content dependent, it is not efficient to use all the modes. In this paper, we propose a fast inter-mode decision algorithm for HEVC by jointly using the inter-level correlation of quadtree structure and the spatiotemporal correlation. There exist strong correlations of the prediction mode, the motion vector and RD cost between different depth levels and between spatially temporally adjacent CUs. We statistically analyze the prediction mode distribution at each depth level and the coding information correlation among the adjacent CUs. Based on the analysis results, three adaptive inter-mode decision strategies are proposed including early SKIP mode decision, prediction size correlation-based mode decision and RD cost correlation-based mode decision. Experimental results show that the proposed overall algorithm can save 49%-52% computational complexity on average with negligible loss of coding efficiency, exhibiting applicability to various types of video sequences. © 1991-2012 IEEE.


Liu Z.,Shanghai University | Liu Z.,Campus University Of Beaulieu | Le Meur O.,Campus University Of Beaulieu | Le Meur O.,University of Rennes 1 | And 2 more authors.
Optics Letters | Year: 2013

We propose an efficient regional histogram (RH)-based computation model for saliency detection in natural images. First, the global histogram is constructed by performing an adaptive color quantization on the original image. Then multiple RHs are built on the basis of the region segmentation result, and the color-spatial similarity between each pixel and each RH is calculated accordingly. Two efficient measures, distinctiveness and compactness of each RH, are evaluated based on the color difference with the global histogram and the color distribution over the whole image, respectively. Finally, the pixel-level saliency map is generated by integrating the color-spatial similarity measures with the distinctiveness and compactness measures. Experimental results on a dataset containing 1000 test images with ground truths demonstrate that the proposed saliency model consistently outperforms state-of-the-art saliency models. © 2013 Optical Society of America.


Legeai F.,Campus University Of Beaulieu | Malpel S.,French National Institute for Agricultural Research | Malpel S.,University of Burgundy | Montagne N.,French National Institute for Agricultural Research | And 9 more authors.
BMC Genomics | Year: 2011

Background: Nocturnal insects such as moths are ideal models to study the molecular bases of olfaction that they use, among examples, for the detection of mating partners and host plants. Knowing how an odour generates a neuronal signal in insect antennae is crucial for understanding the physiological bases of olfaction, and also could lead to the identification of original targets for the development of olfactory-based control strategies against herbivorous moth pests. Here, we describe an Expressed Sequence Tag (EST) project to characterize the antennal transcriptome of the noctuid pest model, Spodoptera littoralis, and to identify candidate genes involved in odour/pheromone detection.Results: By targeting cDNAs from male antennae, we biased gene discovery towards genes potentially involved in male olfaction, including pheromone reception. A total of 20760 ESTs were obtained from a normalized library and were assembled in 9033 unigenes. 6530 were annotated based on BLAST analyses and gene prediction software identified 6738 ORFs. The unigenes were compared to the Bombyx mori proteome and to ESTs derived from Lepidoptera transcriptome projects. We identified a large number of candidate genes involved in odour and pheromone detection and turnover, including 31 candidate chemosensory receptor genes, but also genes potentially involved in olfactory modulation.Conclusions: Our project has generated a large collection of antennal transcripts from a Lepidoptera. The normalization process, allowing enrichment in low abundant genes, proved to be particularly relevant to identify chemosensory receptors in a species for which no genomic data are available. Our results also suggest that olfactory modulation can take place at the level of the antennae itself. These EST resources will be invaluable for exploring the mechanisms of olfaction and pheromone detection in S. littoralis, and for ultimately identifying original targets to fight against moth herbivorous pests. © 2011 Legeai et al; licensee BioMed Central Ltd.


Poivet E.,French National Institute for Agricultural Research | Gallot A.,French National Institute for Agricultural Research | Gallot A.,Campus University Of Beaulieu | Montagne N.,University Pierre and Marie Curie | And 3 more authors.
PLoS ONE | Year: 2013

To better understand the olfactory mechanisms in a lepidopteran pest model species, the cotton leafworm Spodoptera littoralis, we have recently established a partial transcriptome from adult antennae. Here, we completed this transcriptome using next generation sequencing technologies, namely 454 and Illumina, on both adult antennae and larval tissues, including caterpillar antennae and maxillary palps. All sequences were assembled in 77,643 contigs. Their analysis greatly enriched the repertoire of chemosensory genes in this species, with a total of 57 candidate odorant-binding and chemosensory proteins, 47 olfactory receptors, 6 gustatory receptors and 17 ionotropic receptors. Using RT-PCR, we conducted the first exhaustive comparison of olfactory gene expression between larvae and adults in a lepidopteran species. All the 127 candidate olfactory genes were profiled for expression in male and female adult antennae and in caterpillar antennae and maxillary palps. We found that caterpillars expressed a smaller set of olfactory genes than adults, with a large overlap between these two developmental stages. Two binding proteins appeared to be larvae-specific and two others were adult-specific. Interestingly, comparison between caterpillar antennae and maxillary palps revealed numerous organ-specific transcripts, suggesting the complementary involvement of these two organs in larval chemosensory detection. Adult males and females shared the same set of olfactory transcripts, except two male-specific candidate pheromone receptors, two male-specific and two female-specific odorant-binding proteins. This study identified transcripts that may be important for sex-specific or developmental stage-specific chemosensory behaviors. © 2013 Poivet et al.


Liu Z.,Shanghai University | Liu Z.,Campus University Of Beaulieu | Zou W.,INSA Rennes | Li L.,Shanghai University | And 2 more authors.
IEEE Signal Processing Letters | Year: 2014

Co-saliency detection, an emerging and interesting issue in saliency detection, aims to discover the common salient objects in a set of images. This letter proposes a hierarchical segmentation based co-saliency model. On the basis of fine segmentation, regional histograms are used to measure regional similarities between region pairs in the image set, and regional contrasts within each image are exploited to evaluate the intra-saliency of each region. On the basis of coarse segmentation, an object prior for each region is measured based on the connectivity with image borders. Finally, the global similarity of each region is derived based on regional similarity measures, and then effectively integrated with intra-saliency map and object prior map to generate the co-saliency map for each image. Experimental results on two benchmark datasets demonstrate the better co-saliency detection performance of the proposed model compared to the state-of-the-art co-saliency models. © 2013 IEEE.


Tudoran R.,Campus University Of Beaulieu | Costan A.,INSA Rennes | Nano O.,Microsoft | Santos I.,Microsoft | And 2 more authors.
Future Generation Computer Systems | Year: 2016

Scientific and commercial applications operate nowadays on tens of cloud datacenters around the globe, following similar patterns: they aggregate monitoring or sensor data, assess the QoS or run global data mining queries based on inter-site event stream processing. Enabling fast data transfers across geographically distributed sites allows such applications to manage the continuous streams of events in real time and quickly react to changes. However, traditional event processing engines often consider data resources as second-class citizens and support access to data only as a side-effect of computation (i.e. they are not concerned by the transfer of events from their source to the processing site). This is an efficient approach as long as the processing is executed in a single cluster where nodes are interconnected by low latency networks. In a distributed environment, consisting of multiple datacenters, with orders of magnitude differences in capabilities and connected by a WAN, this will undoubtedly lead to significant latency and performance variations. This is namely the challenge we address in this paper, by proposing JetStream, a high performance batch-based streaming middleware for efficient transfers of events between cloud datacenters. JetStream is able to self-adapt to the streaming conditions by modeling and monitoring a set of context parameters. It further aggregates the available bandwidth by enabling multi-route streaming across cloud sites, while at the same time optimizing resource utilization and increasing cost efficiency. The prototype was validated on tens of nodes from US and Europe datacenters of the Windows Azure cloud with synthetic benchmarks and a real-life application monitoring the ALICE experiment at CERN. The results show a 3× increase of the transfer rate using the adaptive multi-route streaming, compared to state of the art solutions. © 2015 Elsevier B.V. All rights reserved.


Bozzelli L.,Campus University Of Beaulieu | Murano A.,University of Naples Federico II | Peron A.,University of Naples Federico II
Formal Methods in System Design | Year: 2010

Model checking is a useful method to verify automatically the correctness of a system with respect to a desired behavior, by checking whether a mathematical model of the system satisfies a formal specification of this behavior. Many systems of interest are open, in the sense that their behavior depends on the interaction with their environment. The model checking problem for finite-state open systems (called module checking) has been intensively studied in the literature. In this paper, we focus on open pushdown systems and we study the related model-checking problem (pushdown module checking, for short) with respect to properties expressed by CTL and CTL * formulas. We show that pushdown module checking against CTL (resp., CTL *) is 2Exptime-complete (resp., 3Exptime-complete). Moreover, we prove that for a fixed CTL or CTL * formula, the problem is Exptime-complete. © 2010 Springer Science+Business Media, LLC.


Maugey T.,Telecom ParisTech | Gauthier J.,Telecom ParisTech | Pesquet-Popescu B.,Telecom ParisTech | Guillemot C.,Campus University Of Beaulieu
ICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings | Year: 2010

The Laplacian model is the standard distribution for correlation noise estimation at the turbodecoder in Wyner-Ziv coding schemes. In practice, this hypothesis is not always satisfied and, regularly, the estimated model sensibly differs from the error distribution. In this work, we prove that using a model better fitted to the true distribution improves the performances, and we thus propose to use the more general exponential power distribution (EPD) which has never been tested in a distributed video coding context. Gains in rate-distortion over the Laplacian model are illustrated by results on several video sequences, showing that the EPD model outperforms the Laplacian one in off-line (oracle) as well as in on-line (practical implementation) modes. These results also indicate that, in some cases, the online EPD model reduces the bitrate even over the off-line Laplacian model. ©2010 IEEE.


Caeiro M.,University of Vigo | Nemeth Z.,MTA SZTAKI Computer and Automation Research Institute | Priol T.,Campus University Of Beaulieu
Proceedings - 19th International Euromicro Conference on Parallel, Distributed, and Network-Based Processing, PDP 2011 | Year: 2011

This paper investigates a chemical workflow enactment model that is intended to coordinate workflows of large set of activities on a large number of resources in a self-evolving nature, based on a chemical analogy. The concept of chemical workflow engine is introduced for a concurrent, self-coordinating enactment exploiting as much parallelism as inherently present. The concept is aimed at supporting a generalized workflow language without any restrictions, modeling most workflow patterns, separating data and control flow, supporting dynamic changes by multiple versions and instances. The paper presents the notion and model of the chemical based coordination. © 2011 IEEE.


Drid H.,Campus University Of Beaulieu | Cousin B.,Campus University Of Beaulieu | Molnar M.,Campus University Of Beaulieu | Molnar M.,INSA Rennes | Lahoud S.,Campus University Of Beaulieu
Computer Communications | Year: 2010

Network survivability is becoming an important issue and a topical subject in WDM optical mesh networks. Many works have studied network survivability. However, few works have focused on survivability in multi-domain optical networks. This paper reviews the literature on survivability against failures in multi-domain optical networks. The main objective of this study is to evaluate and analyze existing solutions and to compare their performance in terms of different criteria: resource utilization, ratio of rejected connections and recovery time. © 2010 Elsevier B.V. All rights reserved.

Loading Campus University Of Beaulieu collaborators
Loading Campus University Of Beaulieu collaborators