Evaluating load balancing policies for performance and energy-efficiency

Nowadays, more and more increasingly hard computations are performed in challenging fields like weather forecasting, oil and gas exploration, and cryptanalysis. Many of such computations can be implemented using a computer cluster with a large number of servers. Incoming computation requests are then, via a so-called load balancing policy, distributed over the servers to ensure optimal performance. Additionally, being able to switch-off some servers during low period of workload, gives potential to reduced energy consumption. Therefore, load balancing forms, albeit indirectly, a trade-off between performance and energy consumption. In this paper, we introduce a syntax for load-balancing policies to dynamically select a server for each request based on relevant criteria, including the number of jobs queued in servers, power states of servers, and transition delays between power states of servers. To evaluate many policies, we implement two load balancers in: (i) iDSL, a language and tool-chain for evaluating service-oriented systems, and (ii) a simulation framework in AnyLogic. Both implementations are successfully validated by comparison of the results.Comment: In Proceedings QAPL'16, arXiv:1610.0769

Novel electrocardiographic criteria for the diagnosis of arrhythmogenic right ventricular cardiomyopathy

Aims: In order to improve the electrocardiographic (ECG) diagnosis of arrhythmogenic right ventricular cardiomyopathy (ARVC), we evaluated novel quantitative parameters of the QRS complex and the value of bipolar chest leads (CF leads) computed from the standard 12 leads. Methods and results: We analysed digital 12-lead ECGs in 44 patients with ARVC, 276 healthy subjects including 44 age and sex-matched with the patients and 36 genotyped members of ARVC families. The length and area of the terminal S wave in V1 to V3 were measured automatically using a common for all 12 leads QRS end. T wave negativity was assessed in V1 to V6 and in the bipolar CF leads computed from the standard 12 leads. The length and area of the terminal S wave were significantly shorter, whereas the S wave duration was significantly longer in ARVC patients compared with matched controls. Among members of ARVC families, those with mutations (n = 15) had shorter QRS length in V2 and V3 and smaller QRS area in lead V2 compared with those without mutations (n = 20). In ARVC patients, the CF leads were diagnostically superior to the standard unipolar precordial leads. Terminal S wave duration in V1 >48 ms or major T wave negativity in CF leads separated ARVC patients from matched controls with 90% sensitivity and 86% specificity. Conclusion: The terminal S wave length and area in the right precordial leads are diagnostically useful and suitable for automatic analysis in ARVC. The CF leads are diagnostically superior to the unipolar precordial leads

Towards Simple Models for Energy-Performance Trade-Offs in Data Centers

In this paper we advocate the use of simple stochastic models to analyse the energy-performance trade-off in data centres. Recently such trade-offs have received increased attention, however, the tools used to make such trade-offs are largely based on simulation and real-life experiments. Although simulations studies are very helpful, we think that simple analytical models, or models based on stochastic Petri nets (or similar description techniques) can be very fruitful in guiding design processes in the early phases.\ud Similarly, we do think that experimental work is very important, however, its results come "after the fact" in the sense that the system has been built already once the experiments are being performed. Our claim is that the\ud use of simple models early in the design phase provides a very good return on investment. This short paper presents some preliminary models that can be used for early-in-design trade-off analyses

Fluid Survival Tool: A Model Checker for Hybrid Petri Nets

Recently, algorithms for model checking Stochastic Time Logic (STL) on Hybrid Petri nets with a single general one-shot transition (HPNG) have been introduced. This paper presents a tool for model checking HPNG models against STL formulas. A graphical user interface (GUI) not only helps to demonstrate and validate existing algorithms, it also eases use. From the output of the model checker, 2D and 3D plots can be generated. The extendable object-oriented tool has been developed using the Model-View-Controller and Facade patterns, Doxygen for documentation and Qt for GUI development written in C++

A 12-month follow-up study of treating overweight schizophrenic patients with aripiprazole

Objective: To investigate the feasibility of switching overweight schizophrenic patients to aripiprazole and to assess the impact of 12 months of aripiprazole treatment on weight in routine practice. Method: This was a non-controlled cohort study in overweight schizophrenic patients. Data were collected before treatment with aripiprazole was started and at 12-month follow-up. Results: A total of 53 patients were included; of these 55% continued using aripiprazole for 12 months. Aripiprazole treatment for 12 months (P = 0.027) and stopping clozapine or olanzapine treatment (P = 0.038) predicted weight loss (>= 3 kg). Patients receiving aripiprazole monotherapy (n = 16, mean -3.0 kg) had similar weight loss than patients receiving aripiprazole in addition to another antipsychotic drug (n = 13, mean -4.4 kg). Conclusion: In routine practice once aripiprazole treatment was started, more than half of the patients remained on aripiprazole and most of them lost weight. Adding aripiprazole to clozapine gave similar weight loss as monotherapy with aripiprazole

Obligations in the Shade: The Application of Fiduciary Directors’ Duties to Shadow Directors

This paper argues that shadow directors, as defined in English law, ought to owe the full range of directors’ duties, both fiduciary and non-fiduciary, enacted in the Companies Act 2006 (CA 2006), ss 171-177, to the relevant company under their influence. Following the enactment of the recent Small Business, Enterprise and Employment Act (SBEEA) 2015, these general duties are likely to apply to shadow directors, although there is still a case to be made as to why shadow directors should owe fiduciary duties to the relevant company. It is argued here that such a relationship is fiduciary in nature, but the current approach deployed in the English courts, based upon the application of Finn’s originally formulated ‘undertaking’ test alone, is inadequate. Given these inadequacies, it is proposed that the Canadian ‘power and discretion’ test be deployed alongside the ‘undertaking’ test, in order to provide a far more comprehensive justification for the application of fiduciary obligations to shadow directors. This position is supported by establishing a theoretical basis for the ‘power and discretion’ test, via Paul Miller’s ‘fiduciary powers theory’, as well as considering the application of such a test to shadow directors

Construction and Performance of Large-Area Triple-GEM Prototypes for Future Upgrades of the CMS Forward Muon System

At present, part of the forward RPC muon system of the CMS detector at the CERN LHC remains uninstrumented in the high-\eta region. An international collaboration is investigating the possibility of covering the 1.6 < |\eta| < 2.4 region of the muon endcaps with large-area triple-GEM detectors. Given their good spatial resolution, high rate capability, and radiation hardness, these micro-pattern gas detectors are an appealing option for simultaneously enhancing muon tracking and triggering capabilities in a future upgrade of the CMS detector. A general overview of this feasibility study will be presented. The design and construction of small (10\times10 cm2) and full-size trapezoidal (1\times0.5 m2) triple-GEM prototypes will be described. During detector assembly, different techniques for stretching the GEM foils were tested. Results from measurements with x-rays and from test beam campaigns at the CERN SPS will be shown for the small and large prototypes. Preliminary simulation studies on the expected muon reconstruction and trigger performances of this proposed upgraded muon system will be reported.Comment: 7 pages, 25 figures, submitted for publication in conference record of the 2011 IEEE Nuclear Science Symposium, Valencia, Spai

A novel application of Fiber Bragg Grating (FBG) sensors in MPGD

We present a novel application of Fiber Bragg Grating (FBG) sensors in the construction and characterisation of Micro Pattern Gaseous Detector (MPGD), with particular attention to the realisation of the largest triple (Gas electron Multiplier) GEM chambers so far operated, the GE1/1 chambers of the CMS experiment at LHC. The GE1/1 CMS project consists of 144 GEM chambers of about 0.5 m2 active area each, employing three GEM foils per chamber, to be installed in the forward region of the CMS endcap during the long shutdown of LHC in 2108-2019. The large active area of each GE1/1 chamber consists of GEM foils that are mechanically stretched in order to secure their flatness and the consequent uniform performance of the GE1/1 chamber across its whole active surface. So far FBGs have been used in high energy physics mainly as high precision positioning and re-positioning sensors and as low cost, easy to mount, low space consuming temperature sensors. FBGs are also commonly used for very precise strain measurements in material studies. In this work we present a novel use of FBGs as flatness and mechanical tensioning sensors applied to the wide GEM foils of the GE1/1 chambers. A network of FBG sensors have been used to determine the optimal mechanical tension applied and to characterise the mechanical tension that should be applied to the foils. We discuss the results of the test done on a full-sized GE1/1 final prototype, the studies done to fully characterise the GEM material, how this information was used to define a standard assembly procedure and possible future developments.Comment: 4 pages, 4 figures, presented by Luigi Benussi at MPGD 2015 (Trieste, Italy). arXiv admin note: text overlap with arXiv:1512.0848

Design of a constant fraction discriminator for the VFAT3 front-end ASIC of the CMS GEM detector

In this work the design of a constant fraction discriminator (CFD) to be used in the VFAT3 chip for the read-out of the triple-GEM detectors of the CMS experiment, is described. A prototype chip containing 8 CFDs was implemented using 130 nm CMOS technology and test results are shown. © CERN 2016

Development and performance of Triple-GEM detectors for the upgrade of the muon system of the CMS experiment

The CMS Collaboration is evaluating GEM detectors for the upgrade of the muon system. This contribution will focus on the R&D performed on chambers design features and will discuss the performance of the upgraded detector