Hyperentangled mixed phased Dicke states: optical design and detection

We present an experimental method to produce 4-qubit phased Dicke states, based on a source of 2-photon hyperentangled states. By introducing quantum noise in the multipartite system in a controlled way, we have tested the robustness of these states. To this purpose the entanglement of the resulting multipartite entangled mixed states has been verified by using a new kind of structural witness.Comment: 6 pages, 3 figure, supplementary information include

Loss-resilient Coding of Texture and Depth for Free-viewpoint Video Conferencing

Free-viewpoint video conferencing allows a participant to observe the remote 3D scene from any freely chosen viewpoint. An intermediate virtual viewpoint image is commonly synthesized using two pairs of transmitted texture and depth maps from two neighboring captured viewpoints via depth-image-based rendering (DIBR). To maintain high quality of synthesized images, it is imperative to contain the adverse effects of network packet losses that may arise during texture and depth video transmission. Towards this end, we develop an integrated approach that exploits the representation redundancy inherent in the multiple streamed videos a voxel in the 3D scene visible to two captured views is sampled and coded twice in the two views. In particular, at the receiver we first develop an error concealment strategy that adaptively blends corresponding pixels in the two captured views during DIBR, so that pixels from the more reliable transmitted view are weighted more heavily. We then couple it with a sender-side optimization of reference picture selection (RPS) during real-time video coding, so that blocks containing samples of voxels that are visible in both views are more error-resiliently coded in one view only, given adaptive blending will erase errors in the other view. Further, synthesized view distortion sensitivities to texture versus depth errors are analyzed, so that relative importance of texture and depth code blocks can be computed for system-wide RPS optimization. Experimental results show that the proposed scheme can outperform the use of a traditional feedback channel by up to 0.82 dB on average at 8% packet loss rate, and by as much as 3 dB for particular frames

Pequeña filosofía de la enunciación

Traducción de Óscar Quezada Macchiavello

Side-information generation for temporally and spatially scalablewyner-ziv codecs

The distributed video coding paradigmenables video codecs to operate with reversed complexity, in which the complexity is shifted from the encoder toward the decoder. Its performance is heavily dependent on the quality of the side information generated by motio estimation at the decoder. We compare the rate-distortion performance of different side-information estimators, for both temporally and spatially scalableWyner-Ziv codecs. For the temporally scalable codec we compared an established method with a new algorithm that uses a linear-motion model to produce side-information. As a continuation of previous works, in this paper, we propose to use a super-resolution method to upsample the nonkey frame, for the spatial scalable codec, using the key frames as reference.We verify the performance of the spatial scalableWZcoding using the state-of-the-art video coding standard H.264/AVC

Ferramenta de Simulação com Abordagem de Sistema Multiagente Híbrida para Gestão Ambiental

Este artigo apresenta um protótipo de sistema computacional que possibilita a realização de simulações do uso do solo. O sistema tem como objetivo auxiliar na análise da dinâmica do uso e cobertura do solo, de tal forma que possa servir como uma ferramenta utilizada na tomada de decisões. O sistema utiliza uma abordagem multiagente e modelo configurável pelo usuário. O modelo leva em consideração certas variáveis proximais, como por exemplo, a presença de estradas, edificações, cursos de água, entre outros. Estas variáveis proximais são utilizadas para identificar as regiões com maior probabilidade de uso antrópico. O sistema permite configurar o modelo de simulação indicando quais variáveis proximais serão utilizadas, a importância de cada uma delas, e a máquina de estados a ser utilizada. O uso da abordagem de sistema multiagente permite a definição de diversos comportamentos para os agentes envolvidos podendo gerar diferentes cenários de simulação. Como resultados experimentais, este trabalho apresenta simulações iniciais para o bioma do cerrado; o qual é reconhecido como um dos maiores biomas brasileiros, além de ser considerado um hotspot da biodiversidade mundial

Semi-automatic algorithm for construction of the left ventricular area variation curve over a complete cardiac cycle

<p>Abstract</p> <p>Background</p> <p>Two-dimensional echocardiography (2D-echo) allows the evaluation of cardiac structures and their movements. A wide range of clinical diagnoses are based on the performance of the left ventricle. The evaluation of myocardial function is typically performed by manual segmentation of the ventricular cavity in a series of dynamic images. This process is laborious and operator dependent. The automatic segmentation of the left ventricle in 4-chamber long-axis images during diastole is troublesome, because of the opening of the mitral valve.</p> <p>Methods</p> <p>This work presents a method for segmentation of the left ventricle in dynamic 2D-echo 4-chamber long-axis images over the complete cardiac cycle. The proposed algorithm is based on classic image processing techniques, including time-averaging and wavelet-based denoising, edge enhancement filtering, morphological operations, homotopy modification, and watershed segmentation. The proposed method is semi-automatic, requiring a single user intervention for identification of the position of the mitral valve in the first temporal frame of the video sequence. Image segmentation is performed on a set of dynamic 2D-echo images collected from an examination covering two consecutive cardiac cycles.</p> <p>Results</p> <p>The proposed method is demonstrated and evaluated on twelve healthy volunteers. The results are quantitatively evaluated using four different metrics, in a comparison with contours manually segmented by a specialist, and with four alternative methods from the literature. The method's intra- and inter-operator variabilities are also evaluated.</p> <p>Conclusions</p> <p>The proposed method allows the automatic construction of the area variation curve of the left ventricle corresponding to a complete cardiac cycle. This may potentially be used for the identification of several clinical parameters, including the area variation fraction. This parameter could potentially be used for evaluating the global systolic function of the left ventricle.</p

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Codificador distribuído de vídeo com complexidade variável a partir de codificação em resolução espacial mista.

Tese (doutorado)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Elétrica, 2009.Recentemente, novas exigências têm surgido para a codificação de vídeo. Estas exigências incluem flutuação da largura de banda, qualidade de serviço e limitações de energia. Em dispositivos móveis é importante limitar o consumo de energia. Tipicamente, o codificador possui uma maior complexidade, requerendo maior consumo de energia que o decodificador. Um novo paradigma, chamado codificação de vídeo distribuída, possibilita a codificação com complexidade reversa, onde o codificador requer um menor esforço computacional do que o decodificador. A codificação de vídeo distribuída é baseada no teorema de Wyner-Ziv para a codificação separada, com decodificação conjunta de fontes correlatas. Assim, um codec distribuído pode ser utilizado em cenários de potência limitada. É proposto um modo de codificação baseado em quadros-chave de resolução espacial completa e quadros intermediários codificados a resolução reduzida mediante um codificador Wyner-Ziv. Um bom desempenho de taxa-distorção é alcançado mediante uma melhor geração da informação lateral no decodificador e um mecanismo automático de alocação de taxa no codificador. Este modo possibilita a redução de complexidade de codificação dos quadros intermediários, seguido de codificação Wyner-Ziv do resíduo. Os coeficientes quantizados do quadro residual são mapeados em cosets sem o uso de um canal de retorno. Para isto, foi feito um estudo dos parâmetros ótimos de codificação na criação dos cosets sem memória. Também, foi elaborado um mecanismo de estimação da correlação estatística entre os sinais. Este mecanismo guia a escolha dos parâmetros de codificação e a alocação de taxa, durante o processo da criação dos cosets. A geração da informação lateral explora a informação obtida da camada base de baixa resolução. No decodificador, a decodificação de canal dos cosets é realizada usando a informação lateral para obter uma versão de alta qualidade do quadro intermediário decodificado. Resultados da complexidade de codificação e do desempenho, em termos de taxa-distorção, são apresentados usando o padrão H.264/AVC. É mostrado que o modo de codificação Wyner-Ziv proposto é competitivo ao ser comparado com a codificação convencional. O modo Wyner-Ziv proposto também possui adaptabilidade na redução de complexidade e suporta um modo de decodificação de baixa complexidade. _______________________________________________________________________________ ABSTRACTRecently, new requirements in video coding have emerged. These requirements include bandwidth fluctuation, quality of service and energy constraints. In handheld mobile devices, it is important to limit the energy consumption. Typically, the encoder has a higher complexity, requiring more energy consumption than the decoder. A new paradigm in video coding, called distributed video coding, enables a reversed complexity coding mode, where the decoder requires more computational effort than the encoder. Distributed video coding is based on the Wyner-Ziv theorem for separately coding but jointly decoding correlated sources. A distributed video codec can be used in power constrained scenarios. We propose a mixed resolution framework based on full resolution key frames and spatial-reduction-based Wyner-Ziv coding of intermediate non-reference frames. Improved rate-distortion performance is achieved by enabling better sideinformation generation at the decoder and better rate-allocation at the encoder. The framework enables reduced encoding complexity by low-resolution encoding of the non-reference frames, followed by Wyner-Ziv coding of the residue. The quantized transform coefficients of the residual frame are mapped to cosets without the use of a feedback channel. For that purpose, a study to select optimal coding parameters in the creation of the memoryless cosets is made. Furthermore, a correlation estimation mechanism that guides the parameter choice process is proposed. This estimation algorithm is one of the main contributions of this work. The side information generation method exploits information for the low resolution coded frames. At the decoder, coset decoding is carried using the side-information to obtain a higher quality version of the decoded frame. Results for the coding complexity and rate-distortion performance are presented using the H.264/AVC codec. It is shown that the proposed Wyner-Ziv coding mode is competitive. It allows a scalable complexity reduction and supports a lowdecoding- complexity mode