QoS and preemption aware scheduling in federated and virtualized Grid computing environments

Resource provisioning is one of the challenges in federated Grid environments. In these environments each Grid serves requests from external users along with local users. Recently, this resource provisioning is performed in the form of Virtual Machines (VMs). The problem arises when there are insufficient resources for local users to be served. The problem gets complicated further when external requests have different QoS requirements. Serving local users could be solved by preempting VMs from external users which impose overheads on the system. Therefore, the question is how the number of VM preemptions in a Grid can be minimized. Additionally, how we can decrease the likelihood of preemption for requests with more QoS requirements. We propose a scheduling policy in InterGrid, as a federated Grid, which reduces the number of VM preemptions and dispatches external requests in a way that fewer requests with QoS constraints get affected by preemption. Extensive simulation results indicate that the number of VM preemptions is decreased at least by 60%, particularly, for requests with more QoS requirements.     

Coordinated load management in Peer-to-Peer coupled federated grid systems

This paper proposes a coordinated load management protocol for Peer-to-Peer?(P2P) coupled federated Grid systems. The participants in the system, such as the resource providers and the consumers who belong to multiple control domains, work together to enable a coordinated federation. The coordinated load management protocol embeds a logical spatial index over a Distributed Hash Table?(DHT) space for efficient management of the coordination objects; the DHT-based space serves as a kind of decentralized blackboard system. We show that our coordination protocol has a message complexity that is logarithmic to the number of nodes in the system, which is significantly better than existing broadcast based coordination protocols. The proposed load management protocol can be applied for efficiently coordinating resource brokering services of distributed computing systems such as grids and PlanetLab. Resource brokering services are the main components that control the way applications are scheduled, managed and allocated in a distributed, heterogeneous, and dynamic Grid computing environments. Existing Grid resource brokers, e-Science application work-flow schedulers, operate in tandem but still lack a coordination mechanism that can lead to efficient application schedules across distributed resources. Further, lack of coordination exacerbates the utilization of various resources (such as computing cycles and network bandwidth). The feasibility of the proposed coordinated load management protocol is studied through extensive simulations.     

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.     

Influence of the concentration of capping agent on synthesizing and analyses of Ceria nano-filler using modified co-precipitation technique

The pure crystalline cerium oxide (CeO₂) nanoparticles were synthesized using optimized content of Ce(NO₃)₃. 6H₂O with varying concentrations of sodium hydroxide (NaOH) (0.5, 1, 1.5, and 2 M) as a precipitation agent in presence of 2.5 wt% poly(vinylpyrrolidone) PVP. All the samples are prepared via the modified coprecipitation technique. The synthesized materials have been analyzed using X-ray diffraction (XRD), Fourier transform infrared (FT-IR), laser Raman, high-resolution scanning electron microscope (HR-SEM), and photo luminescence (PL) analyses. The optimized sample was identified with the help of the above studies that could be analyzed through transverse electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) studies. The cubic structure with the Fm-3 m space group has been confirmed through XRD (JCPDS: 81-0792) and Raman analyses. The FT-IR and energy dispersive X-ray spectroscopy (EDX) analyses ascertain the occurrence of Ce and O species. The as-prepared CeO₂ filler (0, 3, 6, 9, and 12 wt%) is dispersed through the optimized polymer electrolyte Poly (styrene-co-methyl methacrylate) P(S-MMA) (27 wt%)–lithium perchloride (LiClO₄) (8 wt%)–ethylene carbonate + propylene carbonate (EC + PC) (1;1 of 65 wt%) complex system using solution casting technique. P(S-MMA) (27 wt%)–LiClO₄ (8 wt%)–EC + PC (1;1 of 65 wt%)–6 wt% of CeO₂ shows the high ionic conductivity 8.13 × 10⁻⁴ S cm⁻¹.     

Scour in Long Contractions

Experimental results on local scour in long contractions for uniform and nonuniform sediments (gravels and sands) under clear-water scour are presented. An emphasis was given to conduct the experiments on scour in long contractions for gravels. The findings of the experiments are used to describe the effects of various parameters (obtained from dimensional analysis) on equilibrium scour depth under clear-water scour. The equilibrium scour depth increases with decrease in opening ratio and with increase in sediment size for gravels. But the curves of scour depth versus sediment size have considerable sag at the transition of sand and gravel. The scour depth decreases with increase in densimetric Froude number, for larger opening ratios, and increases with increase in approaching flow depth at lower depths. However, it becomes independent of approaching flow depth at higher flow depths. The effect of sediment gradation on scour depth is pronounced for nonuniform sediments, which reduce scour depth significantly due to the formation of armor layer in the scour hole. Using the continuity and energy equations, a simple analytical model for the computation of clear-water scour depth in long contractions is developed with and without sidewall correction for contracted zone. The models agree satisfactorily with the present and other experimental data. Also, a new empirical equation of maximum equilibrium scour depth, which is based on the experimental data at the limiting stability of sediments in approaching channel under clear-water scour, is proposed. The potential predictors of the maximum equilibrium scour depth in long contractions are compared with the experimental data. The comparisons indicate that the equations given by Komura and Lim are the best predictors among those examined.     

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 taxonomy of computer‐based simulations and its mapping to parallel and distributed systems simulation tools

In recent years, extensive research has been conducted in the area of simulation to model large complex systems and understand their behavior, especially in parallel and distributed systems. At the same time, a variety of design principles and approaches for computer‐based simulation have evolved. As a result, an increasing number of simulation tools have been designed and developed. Therefore, the aim of this paper is to develop a comprehensive taxonomy for design of computer‐based simulations, and apply this taxonomy to categorize and analyze various simulation tools for parallel and distributed systems. Copyright © 2004 John Wiley & Sons, Ltd.     

Leakage current and charge in RTV coated insulators under pollution conditions

Room temperature vulcanizing (RTV) silicone rubber coating has excellent leakage current suppression characteristics. It is used extensively on porcelain and glass insulators in pollution prone areas as an anti-pollution measure. A pollution aging chamber has been fabricated and an on line 4-channel personal computer (PC) based data acquisition system has been developed to conduct tests on RTV coated porcelain samples. A study of the dependence of the leakage current and the charge on the flow rate, conductivity and pressure of the solution forming the fog is reported. It was observed that a higher charge and a higher average leakage current were obtained at a higher flow rate and a higher conductivity. The results with coated HV insulators are consistent with those published in the literature with RTV coated fiber glass reinforced plastic (FRP) rods.     

Performance enhancement in coal fired thermal power plants. Part II: steam turbines

This paper presents the results of the performance enhancement study on 22 coal fired thermal power stations of capacities 30–500 MW. The oldest units (30 MW) have served for 33yr and the newer units (500 MW) have been in operation since 7yr. The turbine efficiencies are in the range 31·00–41·90% as compared to the design range of 34·80–43·97%. The isentropic efficiencies are in the range 74·13–86·40% as compared to design values of 83·20–89·10%. Considerable scope for efficiency improvement through low cost solutions: operational optimization, capital overhaul, simple modifications, etc., exists for all classes of units. The efficiencies can be restored to their design values. The developments in turbines over the last quarter of this century which have led to improved isentropic and thermal efficiencies must be adopted for existing units through retrofits, upgrades and revamps. The turbine efficiencies can be improved to 38·0% for 30 MW units and to 47% for 500 MW units. The maximum potential is for improvement in 210 and 500 MW units followed by 110 and 120 MW units. The potential for 30 and 62·5 MW units is rather limited because of their low capacity share, lack of interest in manufacturers to sell spares (because of the low volume of requirement) and large pay back periods for modernisation schemes. Copyright © 1999 John Wiley & Sons, Ltd.     

Neuroscience instrumentation and distributed analysis of brain activity data: a case for eScience on global Grids

The distribution of knowledge (by scientists) and data sources (advanced scientific instruments), and the need for large‐scale computational resources for analyzing massive scientific data are two major problems commonly observed in scientific disciplines. Two popular scientific disciplines of this nature are brain science and high‐energy physics. The analysis of brain‐activity data gathered from the MEG (magnetoencephalography) instrument is an important research topic in medical science since it helps doctors in identifying symptoms of diseases. The data needs to be analyzed exhaustively to efficiently diagnose and analyze brain functions and requires access to large‐scale computational resources. The potential platform for solving such resource intensive applications is the Grid. This paper presents the design and development of MEG data analysis system by leveraging Grid technologies, primarily Nimrod‐G, Gridbus, and Globus. It describes the composition of the neuroscience (brain‐activity analysis) application as parameter‐sweep application and its on‐demand deployment on global Grids for distributed execution. The results of economic‐based scheduling of analysis jobs for three different optimizations scenarios on the world‐wide Grid testbed resources are presented along with their graphical visualization. Copyright © 2005 John Wiley & Sons, Ltd.