A min-max framework for CPU resource provisioning in virtualized servers using ℋ∞ Filters

Dynamic resource provisioning for virtualized server applications is integral to achieve efficient cloud and green computing. In server applications unpredicted workload changes occur frequently. Resource adaptation of the virtual hosts should dynamically scale to the updated demands (cloud computing) as well as co-locate applications to save on energy consumption (green computing). Most importantly, resource transitions during workload surges should occur while minimizing the expected loss due to mismatches of the resource predictions and actual workload demands. Our approach is to minimize the maximum expected loss using the same techniques as in two-person zero-sum games. We develop an H∞ filter that minimizes the worst-case estimation and allocate resources fast. Through simulations our H∞ filter demonstrates its effectiveness and good performance when compared against Kalman-based controllers

Resource Provisioning for Multi-Tier Virtualized Server Applications

Virtualizing the x86-based data center creates a dynamic environment for server application deployment and resource sharing. Resource management in this environment is challenging as applications are under fluctuating workloads causing diverse resource demands across their tiers. Resource allocation adaptation is essential for high performance machine utilization. This paper presents feedback controllers that dynamically adjust the CPU allocations of multi-tier applications in order to adapt to workload changes by considering the resource coupling between utilizations of application components. Our experimental evaluation on a virtualized 3-tier Rubis server application shows that our techniques work effectively

Visibility analysis, spatial experience and EEG recordings in virtual reality environments: The experience of ‘knowing where one is’ and isovist properties as a means to assess the related brain activity

Virtual Reality environments in combination with brain activity recordings using electroencephalography (EEG) offer a fruitful method to investigate the emergence of specific experiential events in response to the built environment. However, real-world experimental settings involve dynamic and complex conditions which are difficult to be controlled in order to test specific hypothesis that are related to neurophysiology. We discuss here several factors that should be taking into account when designing ecological EEG experiments such as a reflective approach on the human spatial experience, consideration of first-person perspectives and a quantitative analysis of the spatial context. The focus of this paper is to propose a methodology that may facilitate the design of virtual reality EEG experiments that aim to investigate the human experience and cognition within and of the built environment. A pilot virtual reality case study is presented to illustrate how the experience of 'suddenly knowing where one is' could be approached. In this case the isovist measurements of area and revelation along participants' paths offer a useful 'tool' that allows us to isolate and study with further analysis of the EEG signal, the moment that this experience might be manifested as neuronal firing patterns in the human brain

Ethnicity and prosperity in east London: How racial inequalities impact experiences of the good life

This working paper explores the London Prosperity Index survey data through an ethnicity lens and provides some preliminary findings concerning on the relation between racial inequality and prosperity. The quantitative data analysis is framed around three thematic issues, identified in qualitative research as critical to experiences of prosperity in east London: livelihoods, feelings about the local area and feelings about the future

Observation of a Triangular to Square Flux Lattice Phase Transition in YBCO

We have used the technique of small-angle neutron scattering to observe magnetic flux lines directly in an YBCO single crystal at fields higher than previously reported. For field directions close to perpendicular to the CuO2 planes, we find that the flux lattice structure changes smoothly from a distorted triangular co-ordination to nearly perfectly square as the magnetic induction approaches 11 T. The orientation of the square flux lattice is as expected from recent d-wave theories, but is 45 deg from that recently observed in LSCO

A detail computational hydro - acoustics analysis for hydrofoils with straight and wavy leading edges

In this paper, we examine the influence of wavy leading edges (WLE) of a lifting surface on the mechanism of cavitation formation and noise generation. The results of two NACA 634-021 hydrofoils with different wavy leading edges are compared with a NACA 634-021 hydrofoil with a straight profile under different operational conditions. This problem is studied numerically using an unsteady RANS solver with a multiphase mixture flow model. The results are contrasted against a hydrofoil with a straight leading edge. The CFD method applied for solving the incompressible hydrodynamic code is combined with the Schnerr-Sauer cavitation model and with the FfowcsWilliams Hawking (FW-H) integral formulation that can solve the hydro-acoustics problem. Furthermore, the spherical wave equation is applied in order to capture the monopole contribution of the cavitation volume fluctuations. The leading wavy edge leads to the generation of streamwise vorticity which causes the attached wake to become unstable leading to smaller cavitation formations resulting to reduced pressure noise

Updating of Mental Representations in Spatial Reasoning: Two pilot ERP Experiments

Bringing together the notions of mental impasses in problem solving and perceptual restructuring of spatial information during re-orientation the present study investigates brain activity in two real-world pilot experiments on spatial reasoning: an orientation pointing task and a Sudoku puzzle. The working hypothesis of this research is that if we approach wayfinding as an instance of problem solving we can create intellectual bridges between labbased experimental situations and real-world scenarios and adopt new perspectives on existing findings. Two pilot ERP experiments have been conducted in an attempt to check the feasibility of mobile EEG (Emotiv) in detecting a distinct pattern of brain activity during the representational update in real-world spatial problem solving. Initial results in both cases suggest a P3- like component might be the brain’s signature of a representational update

The effects of dietary hesperidin and naringin supplementation on lamb performance and meat characteristics

An experiment was conducted to examine the effects of supplementing feed with hesperidin or naringin, bioflavonoids that are abundant and inexpensive by-products of citrus cultivation, on lambs’ growth performance, carcass and meat characteristics. Fourty-four male Chios lambs were randomly assigned to 4 groups. One of the groups served as control (C) and was given a basal diet, whereas the other 3 groups were given the same diet further supplemented with hesperidin at 2500 mg (H), or naringin at 2500 mg (N), or α-tocopheryl acetate at 200 mg (E) per kg feed. At the end of the experiment (35th day), lambs were fasted, weighed and slaughtered. After overnight chilling, samples of longissimus thoracis muscle were taken and were used for meat quality evaluation. No significant differences were observed in final body weight, body weight gain and edible organ weights among the four experimental groups. pH, colour parameters (L, a*, b*), water holding capacity and shear force value of longissimus thoracis muscle were also not significantly influenced by the dietary treatments. Measurement of lipid oxidation values showed that hesperidin or naringin supplementation positively influenced meat antioxidant properties during the refrigerated storage at 4°C for up to 8 days, however to a lesser extent compared to α-tocopheryl acetate. Nowadays, there is a strong interest in isolating antioxidants from natural sources and using them in animal nutrition with the intention to minimize lipid oxidation in meat products. According to the findings of the present study, flavonoids appeared as a great alternative, since they resulted in an improvement of meat antioxidant capacity leading to a prolongation of its shelf-life and an increase of its acceptability in the market

Boundary effects of expectation in human pain perception

Funder: RCUK | Medical Research Council (MRC); doi: https://doi.org/10.13039/501100000265Funder: FONDECYT, 1161378Abstract: Perception of sensory stimulation is influenced by numerous psychological variables. One example is placebo analgesia, where expecting low pain causes a painful stimulus to feel less painful. Yet, because pain evolved to signal threats to survival, it should be maladaptive for highly-erroneous expectations to yield unrealistic pain experiences. Therefore, we hypothesised that a cue followed by a highly discrepant stimulus intensity, which generates a large prediction error, will have a weaker influence on the perception of that stimulus. To test this hypothesis we collected two independent pain-cueing datasets. The second dataset and the analysis plan were preregistered (https://osf.io/5r6z7/). Regression modelling revealed that reported pain intensities were best explained by a quartic polynomial model of the prediction error. The results indicated that the influence of cues on perceived pain decreased when stimulus intensity was very different from expectations, suggesting that prediction error size has an immediate functional role in pain perception

Direct observation of the flux-line vortex glass phase in a type II superconductor

The order of the vortex state in La_{1.9} Sr_{0.1} CuO_{4} is probed using muon spin rotation and small-angle neutron scattering. A transition from a Bragg glass to a vortex glass is observed, where the latter is composed of disordered vortex lines. In the vicinity of the transition the microscopic behavior reflects a delicate interplay of thermally-induced and pinning-induced disorder.Comment: 14 pages, 4 colour figures include