Energy-Efficient Thermal-Aware Autonomic Management of Virtualized HPC Cloud Infrastructure

Virtualized datacenters and clouds are being increasingly considered for traditional High-Performance Computing (HPC) workloads that have typically targeted Grids and conventional HPC platforms. However, maximizing energy efficiency and utilization of datacenter resources, and minimizing undesired thermal behavior while ensuring application performance and other Quality of Service (QoS) guarantees for HPC applications requires careful consideration of important and extremely challenging tradeoffs. Virtual Machine (VM) migration is one of the most common techniques used to alleviate thermal anomalies (i.e., hotspots) in cloud datacenter servers as it reduces load and, hence, the server utilization. In this article, the benefits of using other techniques such as voltage scaling and pinning (traditionally used for reducing energy consumption) for thermal management over VM migrations are studied in detail. As no single technique is the most efficient to meet temperature/performance optimization goals in all situations, an autonomic approach that performs energy-efficient thermal management while ensuring the QoS delivered to the users is proposed. To address the problem of VM allocation that arises during VM migrations, an innovative application-centric energy-aware strategy for Virtual Machine (VM) allocation is proposed. The proposed strategy ensures high resource utilization and energy efficiency through VM consolidation while satisfying application QoS by exploiting knowledge obtained through application profiling along multiple dimensions (CPU, memory, and network bandwidth utilization). To support our arguments, we present the results obtained from an experimental evaluation on real hardware using HPC workloads under different scenarios.     

Proactive thermal management in green datacenters

The increasing demand for faster computing and high storage capacity has resulted in an increase in energy consumption and heat generation in datacenters. Because of the increase in heat generation, cooling requirements have become a critical concern, both in terms of growing operating costs as well as their environmental and societal impacts. Presently, thermal management techniques make an effort to thermally profile and control datacenters’ cooling equipment to increase their efficiency. In conventional thermal management techniques, cooling systems are triggered by the temperature crossing predefined thresholds. Such reactive approaches result in delayed response as the temperature may already be too high, which can result in performance degradation of hardware.     

Automatic word naming recognition for an on-line aphasia treatment system

One of the most common effects among aphasia patients is the difficulty to recall names or words. Typically, word retrieval problems can be treated through word naming therapeutic exercises. In fact, the frequency and the intensity of speech therapy are key factors in the recovery of lost communication functionalities. In this sense, speech and language technology can have a relevant contribution in the development of automatic therapy methods. In this work, we present an on-line system designed to behave as a virtual therapist incorporating automatic speech recognition technology that permits aphasia patients to perform word naming training exercises. We focus on the study of the automatic word naming detector module and on its utility for both global evaluation and treatment. For that purpose, a database consisting of word naming therapy sessions of aphasic Portuguese native speakers has been collected. In spite of the different patient characteristics and speech quality conditions of the collected data, encouraging results have been obtained thanks to a calibration method that makes use of the patients’ word naming ability to automatically adapt to the patients’ speech particularities.     

Early stages of negative PD development in dielectric liquids

The pulse shapes in the early stages of partial discharge (PD) development, well before liquid streamer onset, and obtained with a 500 MHz wide band detection system using needle-to-metallic plane electrodes submerged in a mineral oil, were compared to those measured with needle to mineral oil plane electrodes in air under negative dc potential. All measurements were carried out ≈50% below the breakdown field value, using gap separations between 3 and 25 mm. Whereas the needle to plane discharge behavior in the mineral oil was characterised by discrete sporadic pulses or burst of several pulses of increasing negative amplitude and oscillatory form, the needle to mineral oil plane gap in air gave rise to primarily dense bursts of unidirectional negative pulses with sequentially decreasing amplitude. The pulses had rise times typically of the order of 1 to 2 ns, indicating the involvement of rapid PD mechanisms     

Communication and Coordination in Wireless Sensor and Actor Networks

In this paper, coordination and communication problems in wireless sensor and actor networks (WSANs) are jointly addressed in a unifying framework. A sensor-actor coordination model is proposed based on an event-driven partitioning paradigm. Sensors are partitioned into different sets, and each set is constituted by a data-delivery tree associated with a different actor. The optimal solution for the partitioning strategy is determined by mathematical programming, and a distributed solution is proposed. In addition, a new model for the actor-actor coordination problem is introduced. The actor coordination is formulated as a task assignment optimization problem for a class of coordination problems in which the area to be acted upon needs to be optimally split among different actors. An auction-based distributed solution of the problem is also presented. Performance evaluation shows how global network objectives, such as compliance with real-time constraints and minimum energy consumption, can be achieved in the proposed framework with simple interactions between sensors and actors that are suitable for large-scale networks of energy-constrained devices.     

A demand-assignment algorithm based on a Markov modulated chain prediction model for satellite bandwidth allocation

This article deals with the problem of the design of a control-based demand-assignment algorithm for a satellite access network using a Markov modulated chain traffic prediction model. The objective is to guarantee a target Quality of Service (QoS) to Internet traffic, while efficiently exploiting the air interface. The proposed algorithm is in charge of dynamically partitioning the uplink bandwidth capacity in a satellite spotbeam among the in-progress connections. Such partition is performed aiming at matching the QoS requirements of each connection and maximizing the satellite bandwidth exploitation. A closed-loop Control Theory approach is adopted to efficiently tackle the problem of the delay between bandwidth requests and bandwidth assignments, while minimizing the signaling overhead caused by control messages. The algorithm efficiently copes with both the satellite propagation delay and the delays inherent in the periodic nature of the bandwidth request mechanism. The proposed demand-assignment algorithm and Markov chain traffic prediction model are shown to improve the overall satellite network performance through extensive simulation experiments.     

Doppler ultrasonographic evaluation of blood flow in the superior mesenteric artery in celiac patients and in healthy controls in fasting conditions and after saccharose ingestion

We studied, by means of Doppler ultrasonography, the blood flow in the superior mesenteric artery in 12 untreated patients with celiac disease (nontropical sprue) and in 15 healthy controls; peak systolic velocity, end diastolic velocity, mean velocity, flow volume, and resistive index were measured in the fasting state and at regular intervals after ingestion of 0.5 liter of water containing 50 g of saccharose. Under fasting conditions, celiac patients showed peak systolic velocity, end diastolic velocity, mean velocity, and flow volume values significantly higher than those of normal subjects, whereas resistive index was significantly lower. After saccharose ingestion these parameters showed greater variations in normal subjects than in celiac patients. Fasting end diastolic velocity turned out to be the best parameter to distinguish celiac patients from healthy subjects. Doppler ultrasonography of the superior mesenteric artery could discriminate between normal subjects and celiac patients with overt disease. However, these data need further confirmation given the limited sample that we studied; moreover, the capability of this technique in distinguishing nontropical sprue from other gastrointestinal diseases that cause increasing splanchnic flow remains to be ascertained.     

Expression and function of a recombinant endothelial nitric oxide synthase gene in porcine coronary arteries

PURPOSE: To evaluate the influence of prognostic factors in postoperative radiotherapy of NSCLC with special emphasis on the time interval between surgery and start of radiotherapy. METHODS AND MATERIALS: Between January 1976 and December 1993, 340 cases were treated and retrospectively analyzed meeting the following criteria: complete follow-up; complete staging information including pathological confirmation of resection status; maximum interval between surgery (SX) and radiotherapy (RT) of 12 weeks (median 36 days, range 18 to 84 days); minimum dose of 50 Gy (R0), and maximum dose of 70 Gy (R2). Two hundred thirty patients (68%) had N2 disease; 228 patients were completely resected (R0). One hundred six (31%) had adenocarcinoma, 172 (51%) squamous cell carcinoma. RESULTS: In univariate analysis, Karnofsky performance status (90+ >60-80%; p = 0.019 log rank), resection status stratified for nodal disease (R+ 相似文献   

CRISPR/Cas9-Based Knock-Out of the PMR4 Gene Reduces Susceptibility to Late Blight in Two Tomato Cultivars

Phytophthora infestans, the causal agent of late blight (LB) in tomato (Solanum lycopersicum L.), is a devastating disease and a serious concern for plant productivity. The presence of susceptibility (S) genes in plants facilitates pathogen proliferation; thus, disabling these genes may help provide a broad-spectrum and durable type of tolerance/resistance. Previous studies on Arabidopsis and tomato have highlighted that knock-out mutants of the PMR4 susceptibility gene are tolerant to powdery mildew. Moreover, PMR4 knock-down in potato has been shown to confer tolerance to LB. To verify the same effect in tomato in the present study, a CRISPR–Cas9 vector containing four single guide RNAs (sgRNAs: sgRNA1, sgRNA6, sgRNA7, and sgRNA8), targeting as many SlPMR4 regions, was introduced via Agrobacterium-tumefaciens-mediated transformation into two widely grown Italian tomato cultivars: ‘San Marzano’ (SM) and ‘Oxheart’ (OX). Thirty-five plants (twenty-six SM and nine OX) were selected and screened to identify the CRISPR/Cas9-induced mutations. The different sgRNAs caused mutation frequencies ranging from 22.1 to 100% and alternatively precise insertions (sgRNA6) or deletions (sgRNA7, sgRNA1, and sgRNA8). Notably, sgRNA7 induced in seven SM genotypes a −7 bp deletion in the homozygous status, whereas sgRNA8 led to the production of fifteen SM genotypes with a biallelic mutation (−7 bp and −2 bp). Selected edited lines were inoculated with P. infestans, and four of them, fully knocked out at the PMR4 locus, showed reduced disease symptoms (reduction in susceptibility from 55 to 80%) compared to control plants. The four SM lines were sequenced using Illumina whole-genome sequencing for deeper characterization without exhibiting any evidence of mutations in the candidate off-target regions. Our results showed, for the first time, a reduced susceptibility to Phytophtora infestans in pmr4 tomato mutants confirming the role of KO PMR4 in providing broad-spectrum protection against pathogens.