Glycerol,glucose and 2-acetoacetoxyethyl methacrylate: Effect on methyl linolenate oxidation and yellowing

The effect of glycerol, glucose and acetoacetoxyethyl methacrylate (AAEM) on autoxidation and yellowing of methyl linolenate has been investigated by nuclear magnetic resonance (NMR) and ultraviolet (UV)-Visible spectroscopies. The extent of autoxidation was determined by measuring the NMR integration of vinylic protons with respect to methoxy protons, an internal standard, as a function of time. The extent of yellowing was determined by measuring the difference in absorbance at 400 nm and 450 nm as a function of time. Glycerol and AAEM showed inhibition of autoxidation, but the most significant effect was observed with AAEM. Glucose enhanced the autoxidation of methyl linolenate. Inhibition of yellowing was observed with all these compounds, especially with glycerol and AAEM.     

Effect of thioanisole and trimethylene sulfide on the oxidation and yellowing of methyl linolenate

The effect of thioanisole and trimethylene sulfide on the autoxidation and yellowing of methyl linolenate has been investigated by nuclear magnetic resonance (NMR) and ultraviolet visible spectroscopy, respectively. The progress of autoxidation was followed by measuring the NMR integration of vinylic protons with respect to methoxy protons, which served as the internal standard, as a function of time. The degree of yellowing was determined by measuring the difference in absorbance at 400 nm and 450 nm as a function of time. Both thioanisole and trimethylene sulfide enhanced the autoxidation of methyl linolenate. Inhibition of yellowing was observed only with trimethylene sulfide.     

Room Temperature Magnetism in Free-Standing Nano-Ni/PVDF Composites

Nanocrystalline Ni was incorporated in polyvinylidene fluoride (PVDF) in three different proportions to obtain free-standing flexible film by sol-gel technique. Effect of nano-Ni loading in the PVDF matrix on the optical, microstructural, and magnetic properties of the nano-Ni/PVDF composite material was studied. Variation of magnetic moments with magnetic field at different temperatures was recorded in the composite-free-standing films. X-ray photoelectron spectroscopy studies indicated that incorporated Ni was in Ni²⁺ and Ni⁴⁺ states. Ni²⁺ atomic concentration was found to be significantly larger than Ni⁴⁺ concentration in all the samples suggesting Ni²⁺ in the PVDF lattice are responsible for observed room temperature ferromagnetism.     

Compact hybrid Sierpinski Koch fractal UWB MIMO antenna with pattern diversity

In this article, a compact 2 element UWB MIMO antenna is proposed. It has a compact size of 40 mm × 20 mm (800 mm²). The antenna utilizes hybrid Sierpinski Koch fractal shape as the radiating element. The antenna elements are placed parallel and close to each other. The isolation between the antenna elements is increased by employing a modified stepped ground plane and a reflecting ground stub. The use of stub results in pattern diversity. A U‐ Shaped slot is etched in the radiating element to notch the WLAN band that interferes with UWB. The antenna performance is measured in terms of S‐parameter, radiation pattern and diversity performance. Considering S₁₁ < ?10 dB, the antenna offers an acceptable impedance bandwidth from 2.5 to 11 GHz, with an isolation better than 20 dB over the UWB range. It has a stable omnidirectional pattern. In terms of diversity performance, the antenna has an envelope correlation coefficient (ECC) of <0.1 and capacity loss of <0.1 bps/Hz. The channel capacity of the antenna in the outdoor environment is obtained using Wireless Insite. The channel capacity is found to be 2 Gb/s. The proposed antenna thus can be a good candidate for portable UWB application.     

Libra: a computational economy‐based job scheduling system for clusters

Clusters of computers have emerged as mainstream parallel and distributed platforms for high‐performance, high‐throughput and high‐availability computing. To enable effective resource management on clusters, numerous cluster management systems and schedulers have been designed. However, their focus has essentially been on maximizing CPU performance, but not on improving the value of utility delivered to the user and quality of services. This paper presents a new computational economy driven scheduling system called Libra, which has been designed to support allocation of resources based on the users' quality of service requirements. It is intended to work as an add‐on to the existing queuing and resource management system. The first version has been implemented as a plugin scheduler to the Portable Batch System. The scheduler offers market‐based economy driven service for managing batch jobs on clusters by scheduling CPU time according to user‐perceived value (utility), determined by their budget and deadline rather than system performance considerations. The Libra scheduler has been simulated using the GridSim toolkit to carry out a detailed performance analysis. Results show that the deadline and budget based proportional resource allocation strategy improves the utility of the system and user satisfaction as compared with system‐centric scheduling strategies. Copyright © 2004 John Wiley & Sons, Ltd.     

A computational economy for grid computing and its implementation in the Nimrod-G resource broker

Computational grids that couple geographically distributed resources such as PCs, workstations, clusters, and scientific instruments, have emerged as a next generation computing platform for solving large-scale problems in science, engineering, and commerce. However, application development, resource management, and scheduling in these environments continue to be a complex undertaking. In this article, we discuss our efforts in developing a resource management system for scheduling computations on resources distributed across the world with varying quality of service (QoS). Our service-oriented grid computing system called Nimrod-G manages all operations associated with remote execution including resource discovery, trading, scheduling based on economic principles and a user-defined QoS requirement. The Nimrod-G resource broker is implemented by leveraging existing technologies such as Globus, and provides new services that are essential for constructing industrial-strength grids. We present the results of experiments using the Nimrod-G resource broker for scheduling parametric computations on the World Wide Grid (WWG) resources that span five continents.     

An SCP-based heuristic approach for scheduling distributed data-intensive applications on global grids

Data-intensive Grid applications need access to large data sets that may each be replicated on different resources. Minimizing the overhead of transferring these data sets to the resources where the applications are executed requires that appropriate computational and data resources be selected. In this paper, we consider the problem of scheduling an application composed of a set of independent tasks, each of which requires multiple data sets that are each replicated on multiple resources. We break this problem into two parts: one, to match each task (or job) to one compute resource for executing the job and one storage resource each for accessing each data set required by the job and two, to assign the set of tasks to the selected resources. We model the first part as an instance of the well-known Set Covering Problem (SCP) and apply a known heuristic for SCP to match jobs to resources. The second part is tackled by extending existing MinMin and Sufferage algorithms to schedule the set of distributed data-intensive tasks. Through simulation, we experimentally compare the SCP-based matching heuristic to others in conjunction with the task scheduling algorithms and present the results.     

A prediction system for assessing customer affordability of whole life cycle cost in defence industry

The manufacturing, delivery and support of service contracts in defence aerospace industry require a high financial investment. It is essential that the customer has the financial ability to procure and support the contract from the conceptual and manufacturing phase to the end of the project given the budget constraints. The aim of this paper is to identify the factors that affect customer affordability of defence contracts and develop a customer affordability assessment framework which is implemented as a software prototype system. Two major quantitative factors and twelve qualitative factors were identified, out which seven factors (identified as the major factors) were included within the customer affordability system. Following the identification of factors and development of measures for each, suggested actions to improve customer affordability were also proposed. The research methodology combined both case study and literature review approach with industrial collaboration in the customer affordability system development. The customer affordability system was validated through collaboration with industrial partners and a case study from defence sector and the results showed that the customer affordability system was capable of providing a good assessment of customer affordability.     

EMUSIM: an integrated emulation and simulation environment for modeling,evaluation, and validation of performance of Cloud computing applications

Cloud computing allows the deployment and delivery of application services for users worldwide. Software as a Service providers with limited upfront budget can take advantage of Cloud computing and lease the required capacity in a pay‐as‐you‐go basis, which also enables flexible and dynamic resource allocation according to service demand. One key challenge potential Cloud customers have before renting resources is to know how their services will behave in a set of resources and the costs involved when growing and shrinking their resource pool. Most of the studies in this area rely on simulation‐based experiments, which consider simplified modeling of applications and computing environment. In order to better predict service's behavior on Cloud platforms, we developed an integrated architecture that is based on both simulation and emulation. The proposed architecture, named EMUSIM, automatically extracts information from application behavior via emulation and then uses this information to generate the corresponding simulation model. We performed experiments using an image processing application as a case study and found that EMUSIM was able to accurately model such application via emulation and use the model to supply information about its potential performance in a Cloud provider. We also discuss our experience using EMUSIM for deploying applications in a real public Cloud provider. EMUSIM is based on an open source software stack and therefore it can be extended for analysis behavior of several other applications. Copyright © 2012 John Wiley & Sons, Ltd.