Cost-Effective Resource Provisioning for MapReduce in a Cloud

This paper presents a new MapReduce cloud service model, Cura, for provisioning cost-effective MapReduce services in a cloud. In contrast to existing MapReduce cloud services such as a generic compute cloud or a dedicated MapReduce cloud, Cura has a number of unique benefits. First, Cura is designed to provide a cost-effective solution to efficiently handle MapReduce production workloads that have a significant amount of interactive jobs. Second, unlike existing services that require customers to decide the resources to be used for the jobs, Cura leverages MapReduce profiling to automatically create the best cluster configuration for the jobs. While the existing models allow only a per-job resource optimization for the jobs, Cura implements a globally efficient resource allocation scheme that significantly reduces the resource usage cost in the cloud. Third, Cura leverages unique optimization opportunities when dealing with workloads that can withstand some slack. By effectively multiplexing the available cloud resources among the jobs based on the job requirements, Cura achieves significantly lower resource usage costs for the jobs. Cura's core resource management schemes include cost-aware resource provisioning, VM-aware scheduling and online virtual machine reconfiguration. Our experimental results using Facebook-like workload traces show that our techniques lead to more than 80 percent reduction in the cloud compute infrastructure cost with upto 65 percent reduction in job response times

De-anonymizable location cloaking for privacy-controlled mobile systems

The rapid technology upgrades of mobile devices and the popularity of wireless networks significantly drive the emergence and development of Location-based Services (LBSs), thus greatly expanding the business of online services and enriching the user experience. However, the personal location data shared with the service providers also leave hidden risks on location privacy. Location anonymization techniques transform the exact location of a user into a cloaking area by including the locations of multiple users in the exposed area such that the exposed location is indistinguishable from that of the other users. However in such schemes, location information once perturbed cannot be recovered from the cloaking region and as a result, users of the location cannot obtain fine granular information even when they have access to it. In this paper, we propose Dynamic Reversible Cloaking (DRC) a new de-anonymziable location cloaking mechanism that allows to restore the actual location from the perturbed information through the use of an anonymization key. Extensive experiments using realistic road network traces show that the proposed scheme is efficient, effective and scalable

Preparation, Characterization and Evaluation of Elvitegravir-Loaded Solid Lipid Nanoparticles for Enhanced Solubility and Dissolution Rate

Purpose: To enhance the aqueous solubility and dissolution rate of elvitegravir (EVG) by formulating the drug as solid lipid nanoparticles (SLNs) using solvent injection method.Methods: EVG-loaded SLNs were prepared by solvent injection method. Four different formulations of SLN were prepared using gelucire - 44/14 as lipid core in ethanol, soya lecithin as emulsifier, and polysorbate 80 as surfactant in the aqueous phase. The SLNs were characterized for various physical properties, including particle size, zeta potential, polydispersity, release profile and entrapment efficiency.Results: The yield of SLNs was in the range 151.0 ± 2.4 to 199.1 ± 2.7 nm. Significant changes were observed in mean particle size (nm), Z - potential (mV) and polydispersity index (PDI) of the SLNs by varying the  concentration of cryoprotectant. EVG – SLNs demonstrated a 800 – 1030-fold enhancement in aqueous solubility compared with plain EVG. The dissolution efficiency (DE) for SLNs was > 63 % in all cases and increased up to 83 % with increasing lipid load.Conclusion: Successful preparation and characterization of elvitegravir–loaded solid lipid nanoparticles by solvent injection method has been accomplished in this study.Keywords: Elvitegravir, Solid lipid nanoparticles, Cryoprotectant, Lipid load, Entrapment efficienc

Systematic Review: Challenges in Teaching Writing Skills for Upper Secondary in ESL Classrooms and Suggestions to overcome them

This paper presents a systematic review of relevant published studies on challenges in teaching writing skills for upper secondary in ESL classrooms and solutions to overcome them from year 2012-2020. This systematic review attempts to address two research questions ; i.e. what are the writing challenges of the students and what are the solutions to overcome writing challenges faced by ESL students. 12 single studies and 2 systematic reviews were systematically reviewed and revealed that the most challenges encountered by students in writing are word choice, vocabulary, grammar and poor organisation of ideas. The findings also shed some lights on solutions to overcome the challenges from teachers’ and students’ perspective. Teachers should act as a guidance by providing sample essays, giving feedbacks and choose suitable approach by identifying students’ needs. Meanwhile the students should read more to generate ideas and improve their vocabulary and grammar knowledge

Is anthropogenic sea level fingerprint already detectable in the Pacific ocean ?

Sea level rates up to three times the global mean rate are being observed in the western tropical Pacific since 1993 by satellite altimetry. From recently published studies, it is not yet clear whether the sea level spatial trend patterns of the Pacific Ocean observed by satellite altimetry are mostly due to internal climate variability or if some anthropogenic fingerprint is already detectable. A number of recent studies have shown that the removal of the signal corresponding to the Pacific Decadal Oscillation (PDO)/Interdecadal Pacific Oscillation (IPO) from the observed altimetry sea level data over 1993–2010/2012 results in some significant residual trend pattern in the western tropical Pacific. It has thus been suggested that the PDO/IPO-related internal climate variability alone cannot account for all of the observed trend patterns in the western tropical Pacific and that the residual signal could be the fingerprint of the anthropogenic forcing. In this study, we investigate if there is any other internal climate variability signal still present in the residual trend pattern after the removal of IPO contribution from the altimetry-based sea level over 1993–2013. We show that subtraction of the IPO contribution to sea level trends through the method of linear regression does not totally remove the internal variability, leaving significant signal related to the non-linear response of sea level to El Niño Southern Oscillation (ENSO). In addition, by making use of 21 CMIP5 coupled climate models, we study the contribution of external forcing to the Pacific Ocean regional sea level variability over 1993–2013, and show that according to climate models, externally forced and thereby the anthropogenic sea level fingerprint on regional sea level trends in the tropical Pacific is still too small to be observable by satellite altimetry

ReverseCloak: A Reversible Multi-level Location Privacy Protection System

With the fast popularization of mobile devices and wireless networks, along with advances in sensing and positioning technology, we are witnessing a huge proliferation of Location-based Services (LBSs). Location anonymization refers to the process of perturbing the exact location of LBS users as a cloaking region such that a user's location becomes indistinguishable from the location of a set of other users. However, existing location anonymization techniques focus primarily on single level unidirectional anonymization, which fails to control the access to the cloaking data to let data requesters with different privileges get information with varying degrees of anonymity. In this demonstration, we present a toolkit for ReverseCloak, a location perturbation system to protect location privacy over road networks in a multi-level reversible manner, consisting of an 'Anonymizer' GUI to adjust the anonymization settings and visualize the multilevel cloaking regions over road network for location data owners and a 'De-anonymizer' GUI to de-anonymize the cloaking region and display the reduced region over road network for location data requesters. With the toolkit, we demonstrate the practicality and effectiveness of the ReverseCloak approach

MapReduce analysis for cloud-archived data

Public storage clouds have become a popular choice for archiving certain classes of enterprise data - for example, application and infrastructure logs. These logs contain sensitive information like IP addresses or user logins due to which regulatory and security requirements often require data to be encrypted before moved to the cloud. In order to leverage such data for any business value, analytics systems (e.g. Hadoop/MapReduce) first download data from these public clouds, decrypt it and then process it at the secure enterprise site. We propose VNCache: an efficient solution for MapReduceanalysis of such cloud-archived log data without requiring an apriori data transfer and loading into the local Hadoop cluster. VNcache dynamically integrates cloud-archived data into a virtual namespace at the enterprise Hadoop cluster. Through a seamless data streaming and prefetching model, Hadoop jobs can begin execution as soon as they are launched without requiring any apriori downloading. With VNcache's accurate pre-fetching and caching, jobs often run on a local cached copy of the data block significantly improving performance. When no longer needed, data is safely evicted from the enterprise cluster reducing the total storage footprint. Uniquely, VNcache is implemented with NO changes to the Hadoop application stack. © 2014 IEEE

A QTAIM approach on poly tetrahydrothiophene molecular wire

The present investigation of structural, charge density and electrical characteristics of Au and thiol substituted poly tetrahydrothiophene molecular wire by using quantum chemical calculations has been carried out with density functional theory (DFT). The various applied electric field (0.00 – 0.26 VÅ-1) altered the geometrical parameters and the corresponding electrostatic and transport properties of the molecule has been analyzed. Interstingly, the applied electric field is increased from 0 eV, the Au−S bond distance at the right terminal is faintly longer than the left end; this variation is resulted from the gold atom at the left end which practices stronger electric field when compared with at the right end of TET molecule. The variations in the atomic charges (MPA, NPA) of the molecule for the various applied electric fields have been compared. The HOMO-LUMO gap of the molecule for zero bias is 1.96eV, as the field increases this gap decrease to 1.31 eV. The ESP shows the potential difference between charges accumulated of the molecule for various applied electric field. The applied electric field polarizes the DCC molecule; as a result the dipole moment of the molecule rises from 2.47 to 15.33 D

Analysis and design of a novel six-switch five-level active boost neutral point clamped inverter

This paper presents an analysis and design of a new boost type six-switch five-level Active Neutral Point Clamped (ANPC) inverter based on switched/flying capacitor technique with self-voltage balancing. Compared to major conventional 5-level inverter topologies, such as, Neutral Point Clamped (NPC), Flying Capacitor (FC), Cascaded Hbridge (CHB) and Active NPC (ANPC) topologies, the new topology reduces the dc-link voltage requirement by 50%. Whilst reducing the dc-link voltage requirement, the number and the size of the active and passive components are also reduced without compromising the reactive power capability. The analysis shows that the proposed topology is suitable for wide range of power conversion applications (for example, rolling mills, fans, pumps, marine appliances, mining, tractions, and most prominently grid-connected renewable energy systems). Experimental results from a 1.2- kVA prototype justifies the concept of the proposed inverter with a conversion efficiency of around 97.5% ± 1% for a wide load range