Efficient memory management in VOD disk array servers usingPer-Storage-Device buffering

We present a buffering technique that reduces video-on-demand server memory requirements in more than one order of magnitude. This technique, Per-Storage-Device Buffering (PSDB), is based on the allocation of a fixed number of buffers per storage device, as opposed to existing solutions based on per-stream buffering allocation. The combination of this technique with disk array servers is studied in detail, as well as the influence of Variable Bit Streams. We also present an interleaved data placement strategy, Constant Time Length Declustering, that results in optimal performance in the service of VBR streams. PSDB is evaluated by extensive simulation of a disk array server model that incorporates a simulation based admission test.This research was supported in part by the National R&D Program of Spain, Project Number TIC97-0438.Publicad

Implementation of a Hardware/Software Platform for Real-Timedata-Intensive Applications in Hazardous Environments

Real-Time Technology and Applications Symposium. Brookline, MA, USA, 10-12 Oct. 1996In real-time data-intensive applications, the simultaneous achievement of the required performance and determinism is a difficult issue to address, mainly due to the time needed to perform I/O operations, which is more significant than the CPU processing time. Additional features need to be considered if these applications are intended to perform in hostile environments. In this paper, we address the implementation of a hardware/software platform designed to acquire, transfer, process and store massive amounts of information at sustained rates of several MBytes/sec, capable of supporting real-time applications with stringent throughput requirements under hazardous environmental conditions. A real-world system devoted to the inspection of nuclear power plants is presented as an illustrative examplePublicad

A comprehensive approach in performance evaluation for modernreal-time operating systems

In real-time computing the accurate characterization of the performance and determinism that a particular real-time operating system/hardware combination can provide for real-time applications is essential. This issue is not properly addressed by existing performance metrics mainly due to the lack of completeness and generalization. In this paper we present a set of comprehensive, easy-to-implement and useful metrics covering three basic real-time operating system features: response to external events, intertask synchronization and resource sharing, and intertask data transferring. The evaluation of real-time operating systems using a set of fine-grained metrics is fundamental to guarantee that we can reach the required determinism in real-world applications.Publicad

Infrared glucose portable device

There are quite a few persons worldwide with severe issues to control the glucose level on its blood. Only in Mexico, there are about 10 million persons with this disease and well over 13 deaths in 100 in this country are due to diabetes. In order to help to control this health issue, we are proposing a device to measure in a swift, simple and efficient way abnormality glucose levels in blood by using infrared sensors. Glucose shows a high absorbance to infrared wavelength. By using such characteristic, it is possible to develop a mobile, low-cost electronic device capable to analyse a blood sample by measuring the absorbance in it. The process is performed by using an array of infrared diodes controlled by a low-power consumption microcontroller as well as by several algorithms within a case. A blood sample is put in a substrate within the case. Once analysed, the glucose level of such sample is analysed and displayed on a scree

Preserving Established Communications in IPv6 Multi-homed Sites with MEX

This research was supported by the SAM (Advanced Mobility Services) project, funded by the Spanish National R&D Programme under contract MCYT TIC2002-04531-C04-03.A proper support for multimedia communications transport has to provide fault tolerance capabilities such as the preservation of established connections in case of failures. While multi-homing addresses this issue, the currently available solution based in massive BGP route injection presents serious scalability limitations, since it contributes to the exponential growth of the BGP table size. Alternative solutions proposed for IPv6 fail to provide equivalent facilities to the current BGP based solution. In this paper we present MEX (Muti-homing through EXtension header) a novel proposal for the provision of IPv6 multi-homing capabilities. MEX preserves overall scalability by storing alternative route information in end-hosts while at the same time reduces packet loss by allowing routers to re-route in-course packets. This behavior is enabled by conveying alternative route information within packets inside a newly defined Extension Header. The resulting system provides fault tolerance capabilities and preserves scalability, while the incurred costs, namely deployment and packet overhead, are only imposed to those that benefit from it. An implementation of the MEX host and router components is also presented.Publicad

A meta-analysis of resuscitative endovascular balloon occlusion of the aorta (REBOA) or open aortic cross-clamping by resuscitative thoracotomy in non-compressible torso hemorrhage patients

Background The objective of this systematic review and meta-analysis was to determine the effect of REBOA, compared to resuscitative thoracotomy, on mortality and among non-compressible torso hemorrhage trauma patients. Methods Relevant articles were identified by a literature search in MEDLINE and EMBASE. We included studies involving trauma patients suffering non-compressible torso hemorrhage. Studies were eligible if they evaluated REBOA and compared it to resuscitative thoracotomy. Two investigators independently assessed articles for inclusion and exclusion criteria and selected studies for final analysis. We conducted meta-analysis using random effect models. Results We included three studies in our systematic review. These studies included a total of 1276 patients. An initial analysis found that although lower in REBOA-treated patients, the odds of mortality did not differ between the compared groups (OR 0.42; 95% CI 0.17–1.03). Sensitivity analysis showed that the risk of mortality was significantly lower among patients who underwent REBOA, compared to those who underwent resuscitative thoracotomy (RT) (RR 0.81; 95% CI 0.68–0.97). Conclusion Our meta-analysis, mainly from observational data, suggests a positive effect of REBOA on mortality among non-compressible torso hemorrhage patients. However, these results deserve further investigation

A genomic approach highlights common and diverse effects and determinants of susceptibility on the yeast Saccharomyces cerevisiae exposed to distinct antimicrobial peptides

<p>Abstract</p> <p>Background</p> <p>The mechanism of action of antimicrobial peptides (AMP) was initially correlated with peptide membrane permeation properties. However, recent evidences indicate that action of a number of AMP is more complex and involves specific interactions at cell envelopes or with intracellular targets. In this study, a genomic approach was undertaken on the model yeast <it>Saccharomyces cerevisiae </it>to characterize the antifungal effect of two unrelated AMP.</p> <p>Results</p> <p>Two differentiated peptides were used: the synthetic cell-penetrating PAF26 and the natural cytolytic melittin. Transcriptomic analyses demonstrated distinctive gene expression changes for each peptide. Quantitative RT-PCR confirmed differential expression of selected genes. Gene Ontology (GO) annotation of differential gene lists showed that the unique significant terms shared by treatment with both peptides were related to the cell wall (CW). Assays with mutants lacking CW-related genes including those of MAPK signaling pathways revealed genes having influence on sensitivity to peptides. Fluorescence microscopy and flow cytometry demonstrated PAF26 interaction with cells and internalization that correlated with cell killing in sensitive CW-defective mutants such as Δ<it>ecm33 </it>or Δ<it>ssd1</it>. GO annotation also showed differential responses between peptides, which included ribosomal biogenesis, <it>ARG </it>genes from the metabolism of amino groups (specifically induced by PAF26), or the reaction to unfolded protein stress. Susceptibility of deletion mutants confirmed the involvement of these processes. Specifically, mutants lacking <it>ARG </it>genes from the metabolism of arginine pathway were markedly more resistant to PAF26 and had a functional CW. In the deletant in the arginosuccinate synthetase (<it>ARG1</it>) gene, PAF26 interaction occurred normally, thus uncoupling peptide interaction from cell killing. The previously described involvement of the glycosphingolipid gene <it>IPT1 </it>was extended to the peptides studied here.</p> <p>Conclusions</p> <p>Reinforcement of CW is a general response common after exposure to distinct AMP, and likely contributes to shield cells from peptide interaction. However, a weakened CW is not necessarily indicative of a higher sensitivity to AMP. Additional processes modulate susceptibility to specific peptides, exemplified in the involvement of the metabolism of amino groups in the case of PAF26. The relevance of the response to unfolded protein stress or the sphingolipid biosynthesis, previously reported for other unrelated AMP, was also independently confirmed.</p

Visiones distópicas del underground urbano en Tokio: análisis textual

Cinema has served as the perfect vehicle of expression to illustrate the strange bond that occurs between the corporeal and the filmic image of the cities. In Occidental cinema, this nexus of junction has been reflected on the screen in every way possible. This has not happened in Japanese cinema: historically they avoided making any dystopian processing. The reasons were sundry: from a deeply rooted tradition in a society that almost forbade showing any sign of weakness to the aftermath of a great war. The aim of this article is to demonstrate that some filmmakers have had enough courage and boldness to distort through his films the usual urban portraits. For that purpose a reading and comment of the sequences of four key films to better understand the substantial transformation that has originated in this area.El cine ha servido como el vehículo de expresión perfecto para ilustrar el extraño vínculo que se produce entre lo corpóreo y la imagen fílmica de las ciudades. En el cine occidental, este nexo de unión se ha plasmado en la pantalla de todas las maneras posibles. No ha sido así en el cine japonés: históricamente se evitó efectuar cualquier tratamiento distópico. Los motivos fueron diversos: desde una tradición fuertemente arraigada en una sociedad que casi prohibía mostrar algún signo de debilidad, hasta las secuelas propias de una gran guerra. La finalidad de este artículo es demostrar que algunos cineastas han tenido suficiente valor y audacia para distorsionar a través de sus películas los habituales retratos urbanos. Para ello se realizó una lectura y comentario de las secuencias de cuatro películas claves para comprender mejor la transformación sustancial que se ha originado en este ámbito