SD: a divergence-based estimation method for service demands in cloud systems

Estimating performance models parameters of cloudsystems presents several challenges due to the distributed natureof the applications, the chains of interactions of requests witharchitectural nodes, and the parallelism and coordination mech-anisms implemented within these systems.In this work, we present a new inference algorithm for modelparameters, calledstate divergence(SD) algorithm, to accuratelyestimate resource demands in a complex cloud application.Differently from existing approaches, SD attempts to minimizethe divergence between observed and modeled marginal stateprobabilities for individual nodes within an application, thereforerequiring the availability of probabilistic measures from both thesystem and the underpinning model.Validation against a case study using the Apache CassandraNoSQL database and random experiments show that SD can ac-curately predict demands and improve system behavior modelingand prediction

Management Compensation as a Value-Added Competitive Method for Casual Theme Restaurants

The primary purpose of this study is to propose that the management compensation package at Outback Steakhouse is a value-adding competitive method. Specifically the research focused on a survey of general manager\u27s altitudes in regards to their intentions to seek out new employment and the effect of the compensation plan provided by Outback Steakhouse on the managers\u27 intentions. This research will provide insight into the use of compensation packages and programs as proactive, value-adding competitive methods in retaining good quality managers it casual theme restaurants

A Queueing Network Model for Performance Prediction of Apache Cassandra

NoSQL databases such as Apache Cassandra have attracted large interest in recent years thanks to their high availability, scalability, flexibility and low latency. Still there is limited research work on performance engineering methods for NoSQL databases, which yet are needed since these systems are highly distributed and thus can incur significant cost/performance trade-offs. To address this need, we propose a novel queueing network model for the Cassandra NoSQL database aimed at supporting resource provisioning. The model defines explicitly key configuration parameters of Cassandra such as consistency levels and replication factor, allowing engineers to compare alternative system setups. Experimental results based on the YCSB benchmark indicate that, with a small amount of training for the estimation of its input param- eters, the proposed model achieves good predictive accuracy across different loads and consistency levels. The average performance errors of the model compared to the real results are between 6% and 10%. We also demonstrate the applicability of our model to other NoSQL databases and other possible utilisation of it

Timeshare Owner Preferences - An Analysis of Program and Service Relationships during Recessionary Times

Since the 1970s various industry studies have indicated that the vacation ownership industry has enjoyed unprecedented growth in unit sales, resort growth, and the number of owners (American Resort Devleopment Association [ARDA], 2007; ARDA, 2009a; ARDA, 2009b). However, due to the recent economic downturn these growth metrics are no longer obtainable. This external impact has caused developers to retrench and therefore reflect upon their existing product and service offerings, financial metrics, and consumer markets (ARDA, 2010a; ARDA 2010b). The crux of these findings indicates that the industry has shifted to maintaining and enhancing product and service offerings as a reaction to changing economic conditions. The findings reported in the body of this manuscript represent product and service preferences as collected from a random data pull of their existing ownership base. The study also revealed current preferences of timeshare owners with relation to services provided and products/amenities offered. Management implications and limitations of the current study are discussed

Determining Magnetic Nanoparticle Size Distributions from Thermomagnetic Measurements

Thermomagnetic measurements are used to obtain the size distribution and anisotropy of magnetic nanoparticles. An analytical transformation method is described which utilizes temperature-dependent zero-field cooling (ZFC) magnetization data to provide a quantitative measurement of the average diameter and relative abundance of superparamagnetic nanoparticles. Applying this method to self-assembled MnAs nanoparticles in MnAs-GaAs composite films reveals a log-normal size distribution and reduced anisotropy for nanoparticles compared to bulk materials. This analytical technique holds promise for rapid assessment of the size distribution of an ensemble of superparamagnetic nanoparticles.Comment: Correction Appl. Phys. Lett. 98, 216103 (2011

An elusive nasopharyngeal hamartoma in a neonate

A rare, elusive, mobile, pedunculated nasopharyngeal tumor in a neonate is described. The child was only intermittently symptomatic and the diagnosis was not made until 1 month of age.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46687/1/247_2006_Article_BF02389013.pd

Pulse shape discrimination of charged particles with a silicon strip detector

Abstract A simple and effective pulse shape discrimination technique is applied to a silicon strip detector array. Excellent charge identification from H up to the Ni projectile has been obtained and isotope separation up to N has also been observed. The method we systematically studied is essentially based on a suitable setting of the constant fraction discriminators, and its main advantage is that no additional electronic modules are needed compared to the ones used in the standard TOF technique

Marine ice sheet dynamics: the impacts of ice-shelf buttressing

Marine ice sheets are continent-scale glacial masses that lie partially submerged in the ocean, as applies to significant regions of Antarctica and Greenland. Such ice sheets have the potential to destabilise under a buoyancy-driven instability mechanism, with considerable implications for future sea level. This paper and its companion present a theoretical analysis of marine ice sheet dynamics under the effect of a potentially dominant control of the buttressing force generated by lateral stresses on the downstream floating component of the ice sheet (the ice shelf). The analysis reveals critical conditions under which ice-shelf buttressing suppresses the buoyancy-driven collapse of an ice sheet and elucidates the implications of lateral stresses on grounding-line control and overall ice-sheet structure. Integrations of a suitably simplified quasi-two-dimensional model are conducted, yielding analytical results that provide a quick assessment of steady-state balances for a given ice-sheet configuration. An analytical balance equation describing the spectrum of marine ice sheet flow regimes spanning zero to strong ice-shelf buttressing is developed. It is determined that the dynamics across this spectrum exhibits markedly different flow regimes and structural characteristics. For sufficient buttressing, the grounding line occurs near to where a lateral-drag controlled section of the ice shelf meets the bedrock, implying an independent control of the grounding line by the ice shelf. The role of basal stresses is relegated to controlling only the thickness of the ice sheet upstream of the grounding line, with no significant control of the grounding line itself. It is further demonstrated that lateral stresses are responsible for inducing additional secondary contacts between the ice shelf and the bedrock downstream of the grounding line, resulting in a rich variety of additional steady states. These inducements generate a further stabilising mechanism that can fully suppress grounding-line retreat and eliminate otherwise irreparable hysteresis effects. The results provide a conceptual framework for numerical and observational interpretation of marine ice sheet dynamics, and clarifies the manner in which ice shelves can control grounding-line positions independently. It is thus indicated that a full resolution of the fine details of the flow of ice shelves and the processes controlling their erosion and disintegration is necessary for the confident forecasting of possible ice-sheet collapse over the course of the next few centuries