Learning the optimal synchronization rates in distributed SDN control architectures

Since the early development of Software-DefinedNetwork (SDN) technology, researchers have been concernedwith the idea of physical distribution of the control plane to ad-dress scalability and reliability challenges of centralized designs.However, having multiple controllers managing the networkwhile maintaining a “logically-centralized” network view bringsadditional challenges. One such challenge is how to coordinatethe management decisions made by the controllers which isusually achieved by disseminating synchronization messages ina peer-to-peer manner. While there exist many architecturesand protocols to ensure synchronized network views and drivecoordination among controllers, there is no systematic method-ology for deciding the optimal frequency (or rate) of messagedissemination. In this paper, we fill this gap by introducingthe SDN synchronization problem: how often to synchronize thenetwork views for each controller pair. We consider two differentobjectives; first, the maximization of the number of controllerpairs that are synchronized, and second, the maximization of theperformance of applications of interest which may be affectedby the synchronization rate. Using techniques from knapsackoptimization and learning theory, we derive algorithms withprovable performance guarantees for each objective. Evaluationresults demonstrate significant benefits over baseline schemes thatsynchronize all controller pairs at equal rate

Predicting phase transition pressure in solids: a semiclassical possibility

This is a short review of the physical ideas,algorithm for calculations and some results of a semiclassical theory of the behaviour of materials under high pressure,proposed by P.Savic and R.Kasanin.The theory has found applications from DAC experiments to studies of planetary interior structure.Comment: PDF file,no figure

Subjective Outcome Evaluation of the Community-Based P.A.T.H.S. Project: Views of Program Implementers

The present study adopted subjective outcome evaluation to examine program effectiveness from the views of implementers (N=375) who implemented the community-based Tier 2 Program of the Project P.A.T.H.S. in Hong Kong. The results revealed that most of the program implementers were satisfied with the program content, their own performance, and program benefits. In agreement with previous studies, the satisfaction ratings of both program content and implementer performance positively predicted perceived program benefits. Regarding the influences of different program delivery approaches, programs with the “interest-enhancement” (INT) element received a more positive evaluation from implementers than did the programs without that element. For programs with the “work-related” (WORK) element, parental involvement significantly raised implementers’ satisfaction ratings on their own performance. The current findings provided evidence for the effectiveness of the P.A.T.H.S. Tier 2 Program from the perspective of the implementers

Exploration of the presale property market in China from an institutional perspective

Presales have been used as a major financing mode for real estate development in China. However, there have been limited researches studying the roles of different real estate market players impacting on the efficiency of the property presales, in particular, on the issue of asymmetric information in the market. The paper adopted an institutional approach to study the problems latent in the presale property market. Semi-structured interviews with professionals and industry practitioners were conducted and the findings suggested that the lack of market information, pseudo policy objectives and confusing roles played by major market players are the root of the problems. Restructuring of the institutional arrangement in regard to the financial channels for capital, risk management on developers, custody of the presale proceeds and commitment of the regulatory authorities are necessary in enhancing the market efficiency

Differential hippocampal shapes in posterior cortical atrophy patients: A comparison with control and typical AD subjects.

Posterior cortical atrophy (PCA) is a neurodegenerative syndrome characterized by predominant visual deficits and parieto-occipital atrophy, and is typically associated with Alzheimer's disease (AD) pathology. In AD, assessment of hippocampal atrophy is widely used in diagnosis, research, and clinical trials; its utility in PCA remains unclear. Given the posterior emphasis of PCA, we hypothesized that hippocampal shape measures may give additional group differentiation information compared with whole-hippocampal volume assessments. We investigated hippocampal volume and shape in subjects with PCA (n = 47), typical AD (n = 29), and controls (n = 48). Hippocampi were outlined on MRI scans and their 3D meshes were generated. We compared hippocampal volume and shape between disease groups. Mean adjusted hippocampal volumes were ∼8% smaller in PCA subjects (P < 0.001) and ∼22% smaller in tAD subject (P < 0.001) compared with controls. Significant inward deformations in the superior hippocampal tail were observed in PCA compared with controls even after adjustment for hippocampal volume. Inward deformations in large areas of the hippocampus were seen in tAD subjects compared with controls and PCA subjects, but only localized shape differences remained after adjusting for hippocampal volume. The shape differences observed, even allowing for volume differences, suggest that PCA and tAD are each associated with different patterns of hippocampal tissue loss that may contribute to the differential range and extent of episodic memory dysfunction in the two groups. Hum Brain Mapp, 2015. © 2015 The Authors Human Brain Mapping Published by Wiley Periodicals, Inc

The mu - e Conversion in Nuclei, mu --> e gamma, mu --> 3e Decays and TeV Scale See-Saw Scenarios of Neutrino Mass Generation

We perform a detailed analysis of lepton flavour violation (LFV) within minimal see-saw type extensions of the Standard Model (SM), which give a viable mechanism of neutrino mass generation and provide new particle content at the electroweak scale. We focus, mainly, on predictions and constraints set on each scenario from mu --> e gamma, mu --> 3e and mu - e conversion in the nuclei. In this class of models, the flavour structure of the Yukawa couplings between the additional scalar and fermion representations and the SM leptons is highly constrained by neutrino oscillation measurements. In particular, we show that in some regions of the parameters space of type I and type II see-saw models, the Dirac and Majorana phases of the neutrino mixing matrix, the ordering and hierarchy of the active neutrino mass spectrum as well as the value of the reactor mixing angle theta_{13} may considerably affect the size of the LFV observables. The interplay of the latter clearly allows to discriminate among the different low energy see-saw possibilities.Comment: Expressions for the factors |C_{me}|^2 and |C_{mu3e}|^2 in the mu-e conversion and mu-->3e decay rates, eqs. (36) and (49), respectively, corrected; results in subsections 2.2 and 2.3 quantitatively changed, qualitatively remain the same; figures 2, 3, 4 and 5 replace

Use of a dual reporter plasmid to demonstrate bactofection with an attenuated aroa- derivative of Pasteurella multocida b:2

A reporter plasmid pSRG has been developed which expresses red fluorescent protein (RFP) from a constitutive prokaryotic promoter within Pasteurella multocida B:2 and green fluorescent protein (GFP) from a constitutive eukaryotic promoter within mammalian cells. This construct has been used to determine the location and viability of the bacteria when moving from the extracellular environment into the intracellular compartment of mammalian cells. Invasion assays with embryonic bovine lung (EBL) cells and an attenuated AroA- derivative of Pasteurella multocida B:2 (strain JRMT12), harbouring the plasmid pSRG, showed that RFP-expressing bacteria could be detected intracellularly at 3 h post-invasion. At this stage, some EBL cells harbouring RFP-expressing bacteria were observed to express GFP simultaneously, indicating release of the plasmid into the intracellular environment. At 5 h post-invasion, more EBL cells were expressing GFP, while still harbouring RFP-expressing bacteria. Concurrently, some EBL cells were shown to express only GFP, indicating loss of viable bacteria within these cells. These experiments proved the functionality of the pSRG dual reporter system and the potential of P. multocida B:2 JRMT12 for bactofection and delivery of a DNA vaccine

Protective efficacy against pandemic influenza of seasonal influenza vaccination in children in Hong Kong: a randomized controlled trial

BACKGROUND: The efficacy of seasonal influenza vaccination against 2009 pandemic influenza A(H1N1) remains unclear. METHODS: One child aged 6-17 years in each of 796 households was randomized to receive 2009-2010 seasonal trivalent inactivated influenza vaccine (TIV) or saline placebo between August 2009 and February 2010. Households were followed up with serology, symptom diaries, and collection of respiratory specimens during illnesses. The primary outcomes were influenza infection confirmed by reverse-transcription polymerase chain reaction (RT-PCR) or a >/=4-fold rise in serum antibody titer measured by hemagglutination inhibition assay. RESULTS: Receipt of TIV led to 8-13-fold mean geometric rises in antibody titers against seasonal A and B viruses, but only 1.5-fold mean geometric rises against the pandemic A(H1N1) virus that was not included in the vaccine. Children who received TIV had a reduced risk of seasonal influenza B confirmed by RT-PCR, with a vaccine efficacy estimate of 66% (95% confidence interval [CI], 31%-83%). Children who received TIV also a had reduced risk of pandemic influenza A(H1N1) indicated by serology, with a vaccine efficacy estimate of 47% (95% CI, 15%-67%). CONCLUSIONS: Seasonal TIV prevented pandemic influenza A(H1N1) and influenza B infections in children. Pandemic A(H1N1) circulated at the time of vaccination and for a short time afterward with no substantial seasonal influenza activity during that period. The potential mechanism for seasonal TIV to provide protection, possibly short lived, for children against pandemic A(H1N1) infection despite poor cross-reactive serologic response deserves further investigation. Clinical Trials Registration. NCT00792051.postprin