An Analysis of Performance Interference Effects on Energy-Efficiency of Virtualized Cloud Environments

Co-allocated workloads in a virtualized computing environment often have to compete for resources, thereby suffering from performance interference. While this phenomenon has a direct impact on the Quality of Service provided to customers, it also changes the patterns of resource utilization and reduces the amount of work per Watt consumed. Unfortunately, there has been only limited research into how performance interference affects energy-efficiency of servers in such environments. In reality, there is a highly dynamic and complicated correlation among resource utilization, performance interference and energy-efficiency. This paper presents a comprehensive analysis that quantifies the negative impact of performance interference on the energy-efficiency of virtualized servers. Our analysis methodology takes into account the heterogeneous workload characteristics identified from a real Cloud environment. In particular, we investigate the impact due to different workload type combinations and develop a method for approximating the levels of performance interference and energy-efficiency degradation. The proposed method is based on profiles of pair combinations of existing workload types and the patterns derived from the analysis. Our experimental results reveal a non-linear relationship between the increase in interference and the reduction in energy-efficiency as well as an average precision within +/-5% of error margin for the estimation of both parameters. These findings provide vital information for research into dynamic trade-offs between resource utilization, performance, and energy-efficiency of a data center

A new insight into the coupler curves of the RCCC four-bar linkage

The final publication is available at link.springer.comBased on the condition for four points to lie on the unit sphere, derived using Distance Geometry, a new mathematical formulation for the coupler curves of the RCCC linkage is presented. The relevance of this formulation is not only its simplicity, but the elegant way in which we can obtain the derivative of any variable with respect to any other, and the simple way in which intervals of monotonicity can be detected. All these results are compactly expressed in terms of Gramians and, as a consequence, they have a direct geometric meaning contrarily to what happens with previous approaches based on kinematic loop equations.Peer ReviewedPostprint (author's final draft

Generalized Wishart processes for interpolation over diffusion tensor fields

Diffusion Magnetic Resonance Imaging (dMRI) is a non-invasive tool for watching the microstructure of fibrous nerve and muscle tissue. From dMRI, it is possible to estimate 2-rank diffusion tensors imaging (DTI) fields, that are widely used in clinical applications: tissue segmentation, fiber tractography, brain atlas construction, brain conductivity models, among others. Due to hardware limitations of MRI scanners, DTI has the difficult compromise between spatial resolution and signal noise ratio (SNR) during acquisition. For this reason, the data are often acquired with very low resolution. To enhance DTI data resolution, interpolation provides an interesting software solution. The aim of this work is to develop a methodology for DTI interpolation that enhance the spatial resolution of DTI fields. We assume that a DTI field follows a recently introduced stochastic process known as a generalized Wishart process (GWP), which we use as a prior over the diffusion tensor field. For posterior inference, we use Markov Chain Monte Carlo methods. We perform experiments in toy and real data. Results of GWP outperform other methods in the literature, when compared in different validation protocols

Partial pathogen protection by tick-bite sensitization and epitope recognition in peptide-immunized HLA DR3 transgenic mice

Ticks are notorious vectors of disease for humans, and many species of ticks transmit multiple pathogens, sometimes in the same tick bite. Accordingly, a broad-spectrum vaccine that targets vector ticks and pathogen transmission at the tick/host interface, rather than multiple vaccines against every possible tickborne pathogen, could become an important tool for resolving an emerging public health crisis. The concept for such a tick protective vaccine comes from observations of an acquired tick resistance (ATR) that can develop in non-natural hosts of ticks following sensitization to tick salivary components. Mice are commonly used as models to study immune responses to human pathogens but normal mice are natural hosts for many species of ticks and fail to develop ATR. We evaluated HLA DR3 transgenic (tg) “humanized” mice as a potential model of ATR and assessed the possibility of using this animal model for tick protective vaccine discovery studies. Serial tick infestations with pathogen-free Ixodes scapularis ticks were used to tick-bite sensitize HLA DR3 tg mice. Sensitization resulted in a cytokine skew favoring a Th2 bias as well as partial (57%) protection to infection with Lyme disease spirochetes (Borrelia burgdorferi) following infected tick challenge when compared to tick naïve counterparts. I. scapularis salivary gland homogenate (SGH) and a group of immunoinformatic-predicted T cell epitopes identified from the I. scapularis salivary transcriptome were used separately to vaccinate HLA DR3 tg mice, and these mice also were assessed for both pathogen protection and epitope recognition. Reduced pathogen transmission along with a Th2 skew resulted from SGH vaccination, while no significant protection and a possible T regulatory bias was seen in epitope-vaccinated mice. This study provides the first proof-of-concept for using HLA DR tg “humanized” mice for studying the potential tick protective effects of immunoinformatic- or otherwise-derived tick salivary components as tickborne disease vaccines

Resource dedication problem in a multi-project environment

There can be different approaches to the management of resources within the context of multi-project scheduling problems. In general, approaches to multiproject scheduling problems consider the resources as a pool shared by all projects. On the other hand, when projects are distributed geographically or sharing resources between projects is not preferred, then this resource sharing policy may not be feasible. In such cases, the resources must be dedicated to individual projects throughout the project durations. This multi-project problem environment is defined here as the resource dedication problem (RDP). RDP is defined as the optimal dedication of resource capacities to different projects within the overall limits of the resources and with the objective of minimizing a predetermined objective function. The projects involved are multi-mode resource constrained project scheduling problems with finish to start zero time lag and non-preemptive activities and limited renewable and nonrenewable resources. Here, the characterization of RDP, its mathematical formulation and two different solution methodologies are presented. The first solution approach is a genetic algorithm employing a new improvement move called combinatorial auction for RDP, which is based on preferences of projects for resources. Two different methods for calculating the projects’ preferences based on linear and Lagrangian relaxation are proposed. The second solution approach is a Lagrangian relaxation based heuristic employing subgradient optimization. Numerical studies demonstrate that the proposed approaches are powerful methods for solving this problem

Suppression of growth by multiplicative white noise in a parametric resonant system

The author studied the growth of the amplitude in a Mathieu-like equation with multiplicative white noise. The approximate value of the exponent at the extremum on parametric resonance regions was obtained theoretically by introducing the width of time interval, and the exponents were calculated numerically by solving the stochastic differential equations by a symplectic numerical method. The Mathieu-like equation contains a parameter $\alpha$ that is determined by the intensity of noise and the strength of the coupling between the variable and the noise. The value of $\alpha$ was restricted not to be negative without loss of generality. It was shown that the exponent decreases with $\alpha$, reaches a minimum and increases after that. It was also found that the exponent as a function of $\alpha$ has only one minimum at $\alpha \neq 0$ on parametric resonance regions of $\alpha = 0$. This minimum value is obtained theoretically and numerically. The existence of the minimum at $\alpha \neq 0$ indicates the suppression of the growth by multiplicative white noise.Comment: The title and the description in the manuscript are change

A comparative study on the marginal fit of zirconia cores manufactured by CAD/CAM and copy milling methods

Purpose: The marginal fit of zirconia cores that were produced by CAD/CAM and by copy milling systems was compared and analyzed to confirm the significance of the variation in dental technicians skill between the two systems.Materials and Methods: Using dental resin teeth and individual trays, 30 plaster casts were produced. Fifteen casts were assigned to be used with five different zirconia core manufacturing dental laboratories using the same CAD/CAM system, which were designated as the CC group. The remaining 15 were assigned to be used with five different zirconia core manufacturing dental laboratories using also the same copy milling system and were designated as the CM group. The zirconia cores were fabricated and were cemented onto the casts. The vertical marginal opening was measured under an optical microscope at 75x magnification. The measured vertical marginal discrepancies were analyzed using an independent sample t-test, and the significance of the vertical marginal gap value for each dental laboratory was analyzed by performing the Kruskal-Wallis test.Results: The means and standard deviations for the marginal discrepancies of the CC and CM groups were found to be 102.73 ± 29.73 μm and 82.25 ± 22.37 μm, respectively. The independent sample t-test showed a significant difference between the two systems; the CAD/CAM system showed a larger vertical marginal gap than the copy milling system. The Kruskal-Wallis test indicated that no significant distributional differences were found between the dental laboratories in either the CAD/CAM or the copy milling systems.Conclusions: The copy milling system may produce more accurate zirconia restorations than the CAD/CAM system. The technicians skill of a copy milling system may not be a determining factor influencing the accuracy of a single zirconia core.Purpose: The marginal fit of zirconia cores that were produced by CAD/CAM and by copy milling systems was compared and analyzed to confirm the significance of the variation in dental technicians skill between the two systems. Materials and Methods: Using dental resin teeth and individual trays, 30 plaster casts were produced. Fifteen casts were assigned to be used with five different zirconia core manufacturing dental laboratories using the same CAD/CAM system, which were designated as the CC group. The remaining 15 were assigned to be used with five different zirconia core manufacturing dental laboratories using also the same copy milling system and were designated as the CM group. The zirconia cores were fabricated and were cemented onto the casts. The vertical marginal opening was measured under an optical microscope at 75x magnification. The measured vertical marginal discrepancies were analyzed using an independent sample t-test, and the significance of the vertical marginal gap value for each dental laboratory was analyzed by performing the Kruskal-Wallis test. Results: The means and standard deviations for the marginal discrepancies of the CC and CM groups were found to be 102.73 ± 29.73 µm and 82.25 ± 22.37 µm, respectively. The independent sample t-test showed a significant difference between the two systems; the CAD/CAM system showed a larger vertical marginal gap than the copy milling system. The Kruskal-Wallis test indicated that no significant distributional differences were found between the dental laboratories in either the CAD/CAM or the copy milling systems. Conclusions: The copy milling system may produce more accurate zirconia restorations than the CAD/CAM system. The technicians skill of a copy milling system may not be a determining factor influencing the accuracy of a single zirconia core.OAIID:oai:osos.snu.ac.kr:snu2013-01/102/2008003883/14SEQ:14PERF_CD:SNU2013-01EVAL_ITEM_CD:102USER_ID:2008003883ADJUST_YN:NEMP_ID:A078517DEPT_CD:861CITE_RATE:0FILENAME:dentistry 201311 3 163.pdfDEPT_NM:치의학과EMAIL:[email protected]_YN:NCONFIRM:

Early onset obesity and adrenal insufficiency associated with a homozygous POMC mutation

Isolated hypocortisolism due to ACTH deficiency is a rare condition that can be caused by homozygous or compound heterozygous mutations in the gene encoding proopiomelanocortin (POMC). Loss of function mutations of POMC gene typically results in adrenal insufficiency, obesity and red hair. We describe an 18 month old Hispanic female with congenital adrenal insufficiency, a novel POMC mutation and atypical clinical features. The patient presented at the age of 9 months with hypoglycemia and the endocrine evaluation resulted in a diagnosis of ACTH deficiency. She developed extreme weight gain prompting sequence analysis of POMC, which revealed a homozygous c.231C > A change which is predicted to result in a premature termination codon. The case we report had obesity, hypocortisolism but lacked red hair which is typical for subjects with POMC mutations. Mutations of POMC should be considered in individuals with severe early onset obesity and adrenal insufficiency even when they lack the typical pigmentary phenotype

Tumor-derived exosomes confer antigen-specific immunosuppression in a murine delayed-type hypersensitivity model

Exosomes are endosome-derived small membrane vesicles that are secreted by most cell types including tumor cells. Tumor-derived exosomes usually contain tumor antigens and have been used as a source of tumor antigens to stimulate anti-tumor immune responses. However, many reports also suggest that tumor-derived exosomes can facilitate tumor immune evasion through different mechanisms, most of which are antigen-independent. In the present study we used a mouse model of delayed-type hypersensitivity (DTH) and demonstrated that local administration of tumor-derived exosomes carrying the model antigen chicken ovalbumin (OVA) resulted in the suppression of DTH response in an antigen-specific manner. Analysis of exosome trafficking demonstrated that following local injection, tumor-derived exosomes were internalized by CD11c+ cells and transported to the draining LN. Exosome-mediated DTH suppression is associated with increased mRNA levels of TGF-β1 and IL-4 in the draining LN. The tumor-derived exosomes examined were also found to inhibit DC maturation. Taken together, our results suggest a role for tumor-derived exosomes in inducing tumor antigen-specific immunosuppression, possibly by modulating the function of APCs. © 2011 Yang et al