Channel-Aware Peer Selection in Multi-View Peer-to-Peer Multimedia Streaming

Motivated by the success of the Picture in Picture feature of the traditional TV, several commercial Peer-to-Peer Multi-Media Streaming (P2PMMS) applications now support the multi-view feature, with which a user can simultaneously watch multiple channels on its screen. This paper considers the peer selection problem in multi-view P2PMMS. This problem has been well studied in the traditional single-view P2PMMS; however, it becomes more complicated in multi-view P2PMMS, mainly due to the fact that a peer watching multiple channels joins multiple corresponding overlays. In this paper, we propose a novel peer selection algorithm, called Channel-Aware Peer Selection (CAPS), where a peer selects its neighboring peers based on the channel subscription of the system, in order to efficiently utilize the bandwidth of all peers in the system, especially those peers watching multiple channels. The results of a large-scale simulation with 10,000 peers and 4 channels shows that CAPS can significantly improve the system performance over the straightforward Random Peer Selection (RPS), which is widely used in single-view P2PMMS networks

Network Architectures for Live Peer-to-Peer Media Streaming

Peer-to-Peer (P2P) media streaming networks, motivated by the huge success of P2P file downloading networks, have recently attracted a lot of research interest. However, it is challenging to design P2P media streaming networks because of the stringent time constraints on the delivered media streams, which require more efficient and resilient overlay architectures. In this paper, we focus on live P2P media streaming networks, a promising application flourishing in the Internet and which requires the distribution of live (not stored) multimedia content to subscribers. We review the architectures for live P2P media streaming networks, and consider both overlay topologies and their construction

Variable Neighbor Selection in Live Peer-to-Peer Multimedia Streaming Networks

Data-driven (or swarming based) streaming is one of the popular ways to distribute live multimedia streaming traffic over Peer-to-Peer (P2P) networks. The efficiency and user satisfaction highly depend on the constructed overlays. The common neighbor selection algorithms in existing overlay construction schemes usually randomly select a fixed number of neighbors which satisfy the selection requirements, such as end-to-end delay or a peer\u27s sojourn time. However, this fixed random neighbor-selection algorithm (FRNS) neglects the peers\u27 upload bandwidth heterogeneity and therefore, the upload bandwidth cannot be efficiently used. In this paper, we propose a variable random neighbor-selection (VRNS) scheme to alleviate the problems due to bandwidth heterogeneity, and in which the number of neighbors with different upload bandwidths is dynamically determined by the statistical bandwidth information of the system. Our proposed scheme is shown to outperform FRNS based upon a large volume of carefully designed simulations

All-Optical Network Coding

In this paper, we investigate the application of network coding to all-optical networks from both the algorithmic and infrastructural perspectives. We study the effectiveness of using network coding for optical-layer dedicated protection of multicast traffic which provides robustness against link failures in the network. We present a heuristic for solving this problem and compare it with both inefficient optimal methods and non-network coding approaches. Our experiments show that our heuristic provides near optimal performance while significantly outperforming existing approaches for dedicated multicast protection. We also propose architectures for specialized all-optical circuits capable of performing the processing required for network coding and show how these devices can be effectively deployed in an all-optical multicast network

Network Coding for WDM All-Optical Multicast

Network coding has become a useful means for achieving efficient multicast, and the optical community has started to examine its application to optical networks. However, a number of challenges, including limited processing capability and coarse bandwidth granularity, need to be overcome before network coding can be effectively used in optical networks. In this paper, we address some of these problems. We consider the problem of finding efficient routes to use with coding, and we study the effectiveness of using network coding for optical-layer dedicated protection of multicast traffic. We also propose architectures for all-optical circuits capable of performing the processing required for network coding. Our experiments show that network coding provides a moderate improvement in bandwidth efficiency for unprotected multicast while significantly outperforming existing approaches for dedicated multicast protection

Linear Programming Models For Multi-Channel P2P Streaming Systems

Most of the commercial P2P video streaming deployments support hundreds of channels and are referred to as multichannel systems. Measurement studies show that bandwidth resources of different channels are highly unbalanced and thus recent research studies have proposed various protocols to improve the streaming qualities for all channels by enabling cross-channel cooperation among multiple channels. However, there is no general framework for comparing existing and potential designs for multi-channel P2P systems. The goal of this paper is to establish tractable models for answering the fundamental question in multi-channel system designs: Under what circumstances, should a particular design be used to achieve the desired streaming quality with the lowest implementation complexity? To achieve this goal, we first classify existing and potential designs into three categories, namely Naive Bandwidth allocation Approach (NBA), Passive Channel-aware bandwidth allocation Approach (PCA) and Active Channel-aware bandwidth allocation Approach (ACA). Then, we define the bandwidth satisfaction ratio as a performance metric to develop linear programming models for the three designs. The proposed models are independent of implementations and can be efficiently solved due to the linear property, which provides a way of numerically exploring the design space of multi-channel systems and developing closedform solutions for special systems

A High-Voltage and Low-Noise Power Amplifier for Driving Piezoelectric Stack Actuators

In this paper, based on the principles of general operational amplifiers, a high-voltage operational amplifier is developed. Considering the influences of piezoelectric stack actuators on the circuit, a novel structure using the high-voltage operational amplifier as a noninverting amplifier is proposed. Because of the simple circuit principles and the voltage feedback control structure, the proposed power amplifier has the advantages of low noise and small size, and it can be realized by discrete electric elements easily. In the application of precision positioning, a power amplifier using the proposed circuit principles for driving piezoelectric stack actuators is designed, simulated, and tested. The simulated results show that the proposed power amplifier could conform to the theory of the circuit. The experimental results show that the designed power amplifier conforms to the simulation, the bandwidth of the power amplifier is about 57 kHz, and the ripple of the power amplifier is less than 2 mV. Furthermore, the output of the proposed power amplifier maintains the same type of wave within in a large range of frequency, while the input is the sinusoidal or square wave, and the resolution of the mechanism which the power amplifier is applied in is about 4.5 nm. By selecting the critical electronic elements and using feedback control, the proposed circuit structure is able to realize a low-cost and high-performance power amplifier to drive piezoelectric stack actuators flexibly, which is the novel work of the paper

The interaction between XBP1 and eNOS contributes to endothelial cell migration

Trabalho final de mestrado integrado em Medicina área científica de Urologia, apresentado á Faculdade de Medicina da Universidade de CoimbraINTRODUÇÃO: Nas últimas décadas a nefrectomia parcial tem assumido um papel de destaque no tratamento do carcinoma de células renais. Esta técnica, também denominada cirurgia poupadora de nefrónios, permite remover o tumor na totalidade, preservando o parênquima renal adjacente. As suas indicações tornaram-se mais abrangentes à medida que os resultados se mostraram cada vez mais promissores. Assim, actualmente a nefrectomia parcial é o tratamento padrão do carcinoma de células renais, em detrimento da tradicional nefrectomia radical. Discute-se agora qual das duas, nefrectomia parcial aberta ou laparoscópica, é a melhor opção. OBJECTIVOS: Rever as evidências científicas relativas ao tratamento do carcinoma de células renais pela nefrectomia parcial, aberta e laparoscópica, definindo o papel actual de cada uma delas nesta área. MÉTODOS: Pesquisa na PubMed e Medline de artigos relativos a nefrectomia radical e nefrectomia parcial aberta e laparoscópica, publicados entre 1997 e 2009. Consulta das “Guidelines” da Associação Europeia de Urologia. DESENVOLVIMENTO: A nefrectomia parcial mostra resultados oncológicos semelhantes aos da nefrectomia radical, permitindo uma menor morbilidade renal a longo prazo. A nefrectomia parcial aberta é agora o tratamento recomendado pelas “Guidelines” da Associação Europeia de Urologia para o tratamento de tumores com diâmetro inferior a 4 cm, limitados ao rim, mesmo quando o rim contralateral é normal. As indicações poderão ainda ser alargadas para tumores até 7 cm de diâmetro, dependendo das características do tumor. A nefrectomia parcial laparoscópica, embora tecnicamente mais exigente, é uma boa opção de tratamento em centros com experiência na realização da técnica, revelando bons resultados a curto prazo. CONCLUSÕES: A nefrectomia parcial aberta é actualmente o tratamento padrão do carcinoma de células renais. A nefrectomia parcial laparoscópica revela resultados a curto prazo semelhantes aos da nefrectomia parcial aberta, contudo são necessários estudos confirmando esses resultados a longo prazoINTRODUCTION: In the last decades partial nephrectomy have had an important role in the treatment of renal cell carcinoma. This surgery, also known as nephron-sparing surgery, allows to remove the tumor and to preserve the surrounding healthy renal parenchyma. Moreover, with the evolution of the technique its indications got more comprehensive. So, nowadays, partial nephrectomy is the standard treatment for renal cell carcinoma, instead of the traditional radical nephrectomy. There is now a discussion between which of the two, open or laparoscopic partial nephrectomy, is the best option. OBJECTIVES: Review the scientific evidences related to the treatment of renal cell carcinoma through open and laparoscopic partial nephrectomy, defining the actual role of both in this area. METHODS: Research articles related to radical nephrectomy, open and laparoscopic partial nephrectomies at PubMed and Medline publications between 1997 and 2009. Consult of the Guidelines of European Urology Association. DEVELOPMENT: Partial nephrectomy shows oncological outcomes similar to those of radical nephrectomy with less renal morbidity at long-term follow-up. Open partial nephrectomy is now the recommended treatment by the Guidelines of European Urology Association for the treatment of tumors less than 4 cm, limited to the kidney, even when the other kidney is normal. Indications can also include tumors less than 7 cm, depending on the characteristics of the tumor. Laparoscopic partial nephrectomy, although technically more demanding, is a good option in specialized centers and reveals similar results in a short-term. CONCLUSIONS: Nowadays open partial nephrectomy is the standard treatment of renal cell carcinoma. Laparoscopic partial shows similar results as open surgery in a short-term, however, more studies are needed to confirm this results at long-term. Key-words: Open partial nephrectomy, laparoscopic partial nephrectomy, renal cell carcinoma, indications, results

Formation of Maillard Reaction Products in Heat-Treated Torreya grandis cv. Merrilli Seed Oil and Their Effects on Two Analytical Methods for the Determination of Total Phenolics

The occurrence of Maillard reaction in heated Torreya grandis cv. Merrilli seed oil was verified by detecting browning index and the contents of the Maillard reaction products (MRPs) 3-deoxyglucosone, methylglyoxal and 5-(hydroxymethyl)furfural, and the effects of the MRPs on the quantification of total phenolics using the Folin-Ciocalteu and Fast Blue BB assays were explored. The Folin-Ciocalteu assay showed that the content of total phenolics in the oil increased after treatment at 150 ℃ for 90 to 120 min, while the Fast Blue BB assay showed the opposite result. It was also observed that the absorbance of the oil at a wavelength of 294 nm increased after long-term low-temperature or high-temperature heat treatment. 3-Deoxyglucosone (0.21–0.47 μg/g) and 5-(hydroxymethyl)furfural (0.06–0.40 μg/g) were detected only in the 150 ℃ treated oil, while methylglyoxal (0.67–1.73 μg/g) existed in both oil samples. In the Folin-Ciocalteu assay, the absorbance at a wavelength of 765 nm of 3-deoxyglucosone and methylglyoxal linearly increased with an increase in their concentrations, and the decreasing order of the absorbance of the MRPs at the same concentration was 3-deoxyglucosone > methylglyoxal > 5-(hydroxymethyl)furfural. In the presence of 3-deoxyglucosone, the Folin-Ciocalteu result was greater than the actual value, and the degree of interference was not related to the content of total phenolics in samples, but instead was positively correlated with the concentration of 3-deoxyglucosone. In the Fast Blue BB assay, there was no significant difference in absorbance at 420 nm among the three MRPs. For food matrices prone to the formation of 3-deoxyglucosone and methylglyoxal during processing, the Fast Blue BB assay can be selected instead of the Folin-Ciocalteu assay to mitigate the interferences from the two substances in the quantification of total phenolics