Latency-driven performance in data centres

Data centre based cloud computing has revolutionised the way businesses use computing infrastructure. Instead of building their own data centres, companies rent computing resources and deploy their applications on cloud hardware. Providing customers with well-defined application performance guarantees is of paramount importance to ensure transparency and to build a lasting collaboration between users and cloud operators. A user’s application performance is subject to the constraints of the resources it has been allocated and to the impact of the network conditions in the data centre. In this dissertation, I argue that application performance in data centres can be improved through cluster scheduling of applications informed by predictions of application performance for given network latency, and measurements of current network latency in data centres between hosts. Firstly, I show how to use the Precision Time Protocol (PTP), through an open-source software implementation PTPd, to measure network latency and packet loss in data centres. I propose PTPmesh, which uses PTPd, as a cloud network monitoring tool for tenants. Furthermore, I conduct a measurement study using PTPmesh in different cloud providers, finding that network latency variability in data centres is still common. Normal latency values in data centres are in the order of tens or hundreds of microseconds, while unexpected events, such as network congestion or packet loss, can lead to latency spikes in the order of milliseconds. Secondly, I show that network latency matters for certain distributed applications even in small amounts of tens or hundreds of microseconds, significantly reducing their performance. I propose a methodology to determine the impact of network latency on distributed applications performance by injecting artificial delay into the network of an experimental setup. Based on the experimental results, I build functions that predict the performance of an application for a given network latency. Given the network latency variability observed in data centers, applications’ performance is determined by their placement within the data centre. Thirdly, I propose latency-driven, application performance-aware, cluster scheduling as a way to provide performance guarantees to applications. I introduce NoMora, a cluster scheduling architecture that leverages the predictions of application performance dependent upon network latency combined with dynamic network latency measurements taken between pairs of hosts in data centres to place applications. Moreover, I show that NoMora improves application performance by choosing better placements than other scheduling policies.MEASUREMENT FOR EUROPE: TRAINING AND RESEARCH FOR INTERNET COMMUNICATIONS SCIENCE, European Commission FP7 Marie Curie Innovative Training Networks (ITN) ENDEAVOUR, European Commission Horizon 2020 (H2020) Industrial Leadership (IL

The management of tubo-ovarian abscesses associated with appendicitis

A relatively uncommon medical complication, the tubo-ovarian abscess (TOA) can result from ascending pelvic infection in the female genital tract. The paper aims at exploring the characteristics of patients with TOA and at comparing the outcomes of the surgical management with postoperative recovery. A retrospective analysis of 25 cases diagnosed with bilateral, right or left TOA at “St. Apostol Andrei” Emergency Clinical County Hospital Constanta, Romania between January 2019 and December 2020 was performed. The patients’ clinical characteristics, age, environment of origin, socio-economic background, educational level, the means of contraception used, surgical procedures, and postoperative recovery were analyzed. Out of the 25 cases, 40% presented bilateral TOA, 32% right TOA and 28% left TOA and left adnexectomy. In 3 patients (37.5%) with right TOA, appendicectomy was also performed. In 72% of the cases, a median pubic-umbilical incision was performed. The remaining 7 patients (28%) with left TOA underwent Pfannenstiel incision. All cases had a favorable postoperative evolution, the patients being discharged 5-9 days after surgery, benefiting from antibiotic therapy 10 days after their discharge. The co-existence of appendicitis and adnexal pathology should raise awareness for adopting a surgical strategy in order to prevent postoperative complications

CoLearn: enabling federated learning in MUD-compliant IoT edge networks

Edge computing and Federated Learning (FL) can work in tandem to address issues related to privacy and collaborative distributed learning in untrusted IoT environments. However, deployment of FL in resource-constrained IoT devices faces challenges including asynchronous participation of such devices in training, and the need to prevent malicious devices from participating. To address these challenges we present CoLearn, which build on the open-source Manufacturer Usage Description (MUD) implementation osMUD and the FL framework PySyft. We deploy CoLearn on resource-constrained devices in a lab environment to demonstrate (i) an asynchronous participation mechanism for IoT devices in machine learning model training using a publish/subscribe architecture, (ii) a mechanism for reducing the attack surface in FL architecture by allowing only IoT MUD-compliant devices to participate in the training phases, and (iii) a trade-off between communication bandwidth usage, training time and device temperature (thermal fatigue)

Innovative therapeutic approach to chemical burns produced by vesicants; an experimental study

Vesicants are compounds that cause severe toxic effects on various tissues. Such chemical action causes tissue necrosis, with clinical expression of skin lesions with a burning character and characteristic blisters. Clinical toxic effects of cutaneous vesicles are correlated with the absorbed dose and exposure time. The goals of the study are to evaluate in vitro the skin toxicity produced by the vesicant chemical compound 2-chloroethyl-ethyl sulfide (CEES), to develop a complex antidote formula, and to optimize the therapeutic efficacy by inclusion in controlled release systems. The experimental protocol aims at the in vitro evaluation of the cytotoxicity of the vesicant compound CEES and of the optimized complex antidote, using the MTT cell viability test. Optimization of the complex antidote formula was achieved by developing and in vitro and in vivo testing of a fixed combination of active substances with anti-inflammatory and antioxidant effects, formulated as a solution with cutaneous administration. In vitro cytotoxicity tests on fibroblast cultures revealed the protective effect of the newly developed antidote solution, specifically a dose-related effect in the case of vesicant exposure

Enabling event-triggered data plane monitoring

We propose a push-based approach to network monitoring that allows the detection, within the dataplane, of traffic aggregates. Notifications from the switch to the controller are sent only if required, avoiding the transmission or processing of unnecessary data. Furthermore, the dataplane iteratively refines the responsible IP prefixes, allowing the controller to receive information with a flexible granularity. We implemented our solution, Elastic Trie, in P4 and for two different FPGA devices. We evaluated it with packet traces from an ISP backbone. Our approach can spot changes in the traffic patterns and detect (with 95% of accuracy) either hierarchical heavy hitters with less than 8KB or superspreaders with less than 300KB of memory, respectively. Additionally, it reduces controller-dataplane communication overheads by up to two orders of magnitude with respect to state-of-the-art solutions

Periodontitis and Heart Disease: Current Perspectives on the Associative Relationships and Preventive Impact

Due to the important advancement and the accumulation of new evidence on the periodontitis-cardiovascular disease (CVD) relationship as well as the major medical, economic and social burden caused by both diseases this chapter aims to review existing epidemiological and pathogenetic links related to this topic. Also, this chapter aims to highlight the impact of the periodontitis-CVD relationships on clinical practice and on the preventive approaches targeting to decrease the impact of periodontitis on CVD. Periodontitis is an infectious disease eliciting local and general inflammation, which leads to periodontal destruction and systemic involvement. Several pathways could explain the link between periodontitis and CVD such as bacteraemia, chronic persistent systemic inflammation and oxidative stress. The first step in the treatment of periodontitis addresses the elimination of microbial components, which lead to a decrease in local and systemic inflammation. Periodontal therapy seems to positively impact CVD. Specialists should inform patients with CVD on the negative impact of periodontitis on their systemic status and refer patients to the periodontist for an extensive examination as routine management of CVD. Some possible risks of periodontal therapy should be considered in patients undergoing antithrombotic medication

Translation of the Fugl-Meyer assessment into Romanian: Transcultural and semantic-linguistic adaptations and clinical validation

PurposeThe Fugl-Meyer Assessment (FMA) scale, which is widely used and highly recommended, is an appropriate tool for evaluating poststroke sensorimotor and other possible somatic deficits. It is also well-suited for capturing a dynamic rehabilitation process. The aim of this study was to first translate the entire sensorimotor FMA scale into Romanian using the transcultural and semantic-linguistic adaptations of its official afferent protocols and to then validate it using the preliminary clinical evaluation of inter- and intra-rater reliability and relevant concurrent validity.MethodsThrough three main steps, we completed a standardized procedure for translating FMA's official afferent evaluation protocols into Romanian and their transcultural and semantic-linguistic adaptation for both the upper and lower extremities. For relevant clinical validation, we evaluated 10 patients after a stroke two times: on days 1 and 2. All patients were evaluated simultaneously by two kinesi-physiotherapists (generically referred to as KFT1 and KFT2) over the course of 2 consecutive days, taking turns in the roles of an examiner and observer, and vice versa (inter-rater). Two scores were therefore obtained and compared for the same patient, i.e., being afferent to an inter-rater assay by comparing the assessment outcomes obtained by the two kinesi-physiotherapists, in between, and respectively, to the intra-rater assay: based on the evaluations of the same kinesi-physiotherapist, in two consecutive days, using a rank-based method (Svensson) for statistical analysis. We also compared our final Romanian version of FMA's official protocols for concurrent validity (Spearman's rank correlation statistical method) to both of the widely available assessment instruments: the Barthel Index (BI) and the modified Rankin scale (mRS).ResultsSvensson's method confirmed overall good inter- and intra-rater results for the main parts of the final Romanian version of FMA's evaluation protocols, regarding the percentage of agreement (≥80% on average) and for disagreement: relative position [RP; values outside the interval of (−0.1, 0.1) in only two measurements out of the 56 comparisons we did], relative concentration [RC; values outside the interval of (−0.1, 0.1) in only nine measurements out of the same 56 comparisons done], and relative rank variation [RV; all values within an interval of (0, 0.1) in only five measurements out of the 56 comparisons done]. High correlation values were obtained between the final Romanian version of FMA's evaluation protocols and the BI (ρ = 0.9167; p = 0.0002) for FMA–upper extremity (FMA-UE) total A-D (motor function) with ρ = 0.6319 and for FMA-lower extremity (FMA-LE) total E-F (motor function) with p = 0.0499, and close to the limit, with the mRS (ρ = −0.5937; p = 0.0704) for FMA-UE total A-D (motor function) and (ρ = −0.6615; p = 0.0372) for FMA-LE total E-F (motor function).ConclusionsThe final Romanian version of FMA's official evaluation protocols showed good preliminary reliability and validity, which could be thus recommended for use and expected to help improve the standardization of this assessment scale for patients after a stroke in Romania. Furthermore, this endeavor could be added to similar international translation and cross-cultural adaptations, thereby facilitating a more appropriate comparison of the evaluation and outcomes in the management of stroke worldwide

Parallel Computing Methods For Particle Accelerator Design

We present methods for parallelizing the transport map construction for multi-core processors and for Graphics Processing Units (GPUs). We provide an efficient implementation of the transport map construction. We describe a method for multi-core processors using the OpenMP framework which brings performance improvement over the serial version of the map construction. We developed a novel and efficient algorithm for multivariate polynomial multiplication for GPUs and we implemented it using the CUDA framework. We show the benefits of using the multivariate polynomial multiplication algorithm for GPUs in the map composition operation for high orders. Finally, we present an algorithm for map composition for GPUs