CloudScope: diagnosing and managing performance interference in multi-tenant clouds

© 2015 IEEE.Virtual machine consolidation is attractive in cloud computing platforms for several reasons including reduced infrastructure costs, lower energy consumption and ease of management. However, the interference between co-resident workloads caused by virtualization can violate the service level objectives (SLOs) that the cloud platform guarantees. Existing solutions to minimize interference between virtual machines (VMs) are mostly based on comprehensive micro-benchmarks or online training which makes them computationally intensive. In this paper, we present CloudScope, a system for diagnosing interference for multi-tenant cloud systems in a lightweight way. CloudScope employs a discrete-time Markov Chain model for the online prediction of performance interference of co-resident VMs. It uses the results to optimally (re)assign VMs to physical machines and to optimize the hypervisor configuration, e.g. the CPU share it can use, for different workloads. We have implemented CloudScope on top of the Xen hypervisor and conducted experiments using a set of CPU, disk, and network intensive workloads and a real system (MapReduce). Our results show that CloudScope interference prediction achieves an average error of 9%. The interference-aware scheduler improves VM performance by up to 10% compared to the default scheduler. In addition, the hypervisor reconfiguration can improve network throughput by up to 30%

Smoothing semi-smooth stable Godeaux surfaces

We show that all the semi-smooth stable complex Godeaux surfaces, classified in [M. Franciosi, R. Pardini and S. Rollenske, Ark. Mat. 56 (2018), no. 2, 299–317], are smoothable and that the moduli stack is smooth of the expected dimension 8 at the corresponding points

I-surfaces with one T-singularity

We classify normal stable surfaces with KX2=1, pg= 2 and q= 0 with a unique singular point which is a non-canonical T-singularity, thus exhibiting two divisors in the main component and a new irreducible component of the moduli space of stable surfaces M¯ 1 , 3

Conventional MRI-Derived Biomarkers of Adult-Type Diffuse Glioma Molecular Subtypes: A Comprehensive Review

The introduction of molecular criteria into the classification of diffuse gliomas has added interesting practical implications to glioma management. This has created a new clinical need for correlating imaging characteristics with glioma genotypes, also known as radiogenomics or imaging genomics. Although many studies have primarily focused on the use of advanced magnetic resonance imaging (MRI) techniques for radiogenomics purposes, conventional MRI sequences remain the reference point in the study and characterization of brain tumors. A summary of the conventional imaging features of glioma molecular subtypes should be useful as a tool for daily diagnostic brain tumor management. Hence, this article aims to summarize the conventional MRI features of glioma molecular subtypes in light of the recent literature

Thermoreflectance investigation of the antiferromagnetic and paramagnetic phases of Cr

Thermoreflectance measurements have been performed on Cr single crystals at several temperatures above and below the Néel temperature. We observe dramatic changes induced by the magnetic phase transition. In contrast, static optical data fail to show appreciable differences in the (0.5-5.0)-eV photon-energy range. Magnetic ordering gives rise to the disappearance of transitions involving specific regions of the Fermi surface. New critical-point absorptions appear at the boundaries of the new Brillouin zone in antiferromagnetic Cr. Most of the observed experimental features have been identified by comparison with recent band-structure calculations

The Role of Maintenance Operator in Industrial Manufacturing Systems: Research Topics and Trends

Maintenance contributes to gaining high business performance, guarantees system availability and reliability as well as safe and sustainable operations. Maintenance activity effectiveness depends on competences and the skills of operators whose performance strongly affects maintenance and production operations. The research field of human issues in industrial maintenance was deeply addressed in the literature; however, the current industrial paradigm, which focusses on the integration of new technologies in conventional manufacturing operations to support human performance, sheds light on new challenges for enterprises and opportunities for research in this field. While some literature reviews in the field of human errors and human factors are available, no study investigated the main topics, research trends and challenges related to the role of maintenance operators in manufacturing systems. This paper addresses the current state-of-the-art role of maintenance operators in manufacturing systems, providing an overview of the main studies. A systematic literature review was carried out to identify significant papers. Then, a topic modelling algorithm was used to detect the main topics of the selected papers to provide the research trends of the subject. The identified topics provided interesting research insights on the human role in industrial maintenance. Research trends and further research opportunities were defined

Electronic structure of Nb-Mo alloys

Thermoreflectance measurements on NbxMo1−x alloys (x=0.2, 0.5, 0.8) have been carried out in the 0.5-5.0 eV energy region. Augmented-plane-wave (APW) calculations for Nb at two different lattice parameters and for Mo, as well as coherent-potential-approximation calculations (CPA), have been carried out and have been used in the interpretation of the experimental results. Several optical transitions [Σ1(EF)→Σ3, G4(EF)→G1,N2→N′1], have been identified, and their concentration dependence followed. These results contribute significantly toward putting the interpretation of the optical properties of Nb, Mo, and their alloys on a much more secure footing. In particular, it has been confirmed that while the lower conduction bands behave roughly as predicted by the rigid-band model, the higher-lying conduction bands show distinctly non-rigid-band-like behavior