There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

Praise for the Third Edition: "This is one of the best books available. Its excellent organizational structure allows quick reference to specific models and its clear presentation . . . solidifies the understanding of the concepts being presented."IIE Transactions on Operations EngineeringThoroughly revised and expanded to reflect the latest developments in the field, Fundamentals of Queueing Theory, Fourth Edition continues to present the basic statistical principles that are necessary to analyze the probabilistic nature of queues. Rather than presenting a narrow focus on the subject, this update illustrates the wide-reaching, fundamental concepts in queueing theory and its applications to diverse areas such as computer science, engineering, business, and operations research.This update takes a numerical approach to understanding and making probable estimations relating to queues, with a comprehensive outline of simple and more advanced queueing models. Newly featured topics of the Fourth Edition include:Retrial queuesApproximations for queueing networksNumerical inversion of transformsDetermining the appropriate number of servers to balance quality and cost of serviceEach chapter provides a self-contained presentation of key concepts and formulae, allowing readers to work with each section independently, while a summary table at the end of the book outlines the types of queues that have been discussed and their results. In addition, two new appendices have been added, discussing transforms and generating functions as well as the fundamentals of differential and difference equations. New examples are now included along with problems that incorporate QtsPlus software, which is freely available via the book's related Web site.With its accessible style and wealth of real-world examples, Fundamentals of Queueing Theory, Fourth Edition is an ideal book for courses on queueing theory at the upper-undergraduate and graduate levels. It is also a valuable resource for researchers and practitioners who analyze congestion in the fields of telecommunications, transportation, aviation, and management science.

Fundamentals of Queueing Theory

/pdf/a-break-in-the-clouds-towards-a-cloud-definition-svovsw1r5a.pdf

A Break in the Clouds: Towards a Cloud Definition

CO2 conversion covers a wide range of possible application areas from fuels to bulk and commodity chemicals and even to specialty products with biological activity such as pharmaceuticals. In the present review, we discuss selected examples in these areas in a combined analysis of the state-of-the-art of synthetic methodologies and processes with their life cycle assessment. Thereby, we attempted to assess the potential to reduce the environmental footprint in these application fields relative to the current petrochemical value chain. This analysis and discussion differs significantly from a viewpoint on CO2 utilization as a measure for global CO2 mitigation. Whereas the latter focuses on reducing the end-of-pipe problem “CO2 emissions” from todays’ industries, the approach taken here tries to identify opportunities by exploiting a novel feedstock that avoids the utilization of fossil resource in transition toward more sustainable future production. Thus, the motivation to develop CO2-based chemistry does...

Sustainable Conversion of Carbon Dioxide: An Integrated Review of Catalysis and Life Cycle Assessment

Despite hospitality and tourism researchers’ recent attempts on examining different aspects of online word-of-mouth [WOM], its impact on hotel sales remains largely unknown in the existing literature. To fill this void, we conduct a study to empirically investigate the impact of online consumer-generated reviews on hotel room sales. Utilizing data collected from the largest travel website in China, we develop a fixed effect log-linear regression model to assess the influence of online reviews on the number of hotel room bookings. Our results indicate a significant relationship between online consumer reviews and business performance of hotels.

The impact of online user reviews on hotel room sales [Summary]

The contemporary business environment can be seen as a logical effect of eBusiness, advanced integrated networks, and software services. In such an environment application deployment models have revolutionized the way businesses interact, collaborate and transact with customers, suppliers, partners, employees and shareholders. The purpose of our work is to develop a generic model for performance analysis of software services in order to facilitate enterprises to attach their customers more tightly by an effective service delivery which in turn optimizes business processes at different steps. This communications enablement allows not only greater synergy and velocity among vendors, suppliers and partners within the value creation and delivery chain of the business, but also, creates responsive and seamless customer service.

A Generic Approach to the Services Delivery in Enterprise eBusiness Platforms

Phosphorus (P) deficiency is a major constraint to crop growth due to strong soil P fixation. The effects of molybdenum (Mo) on leaf anatomy and dynamics of rhizosphere P in Mo-inefficient crops have still not been investigated. A field study was conducted to investigate the effects of long-term fertilization on dynamics of rhizosphere P transformations and leaf anatomy in Mo-inefficient wheat consisting of Mo (+Mo) and without Mo applied (−Mo) treatments. The results revealed that Mo supply increased plant biomass, grain yield, uptake of P and Mo by 34.9%, 14.8%, 98.1% and 654.1% respectively and preserved the leaf cuticle, stomata, chloroplast, and mesophyll tissue cell configuration. Molybdenum application significantly increased the concentration of radially available P fractions [NaHCO3-Pi (115.5 to 129.8 mg kg−1 and 67.4 to 80.7 mg kg−1) and H2O-Pi (14.4–21.9 mg kg−1 and 4.63–6.40 mg kg−1)] in rhizosphere and non-rhizosphere soils, respectively. The acid phosphatase (ACP) activity (19.5 μmol day−1 g−1) was highest during March as compared to alkaline (ALP) and phytase (PHY) enzymes in the rhizosphere soil of +Mo treatment. The highest expression of gene lppC (6.11) was observed in rhizosphere soil as compared to non-rhizosphere soil which indicated that higher gene expressions induced the higher P enzymatic activities. Our findings suggest that Mo fertilizer application increases P availability through induced alteration in dynamics of rhizosphere soil P fractions, higher P and Mo assimilation and phosphatases enzymes activities along with preserving the leaf anatomy and ultrastructure of Mo-inefficient wheat.

Mo-Inefficient Wheat Response Toward Molybdenum Supply in Terms of Soil Phosphorus Availability

Pedigree records of 17250 Thalli sheep with 17030 lambings maintained at the Livestock Experiment Station, Rakh Ghulaman, Distt. Bhakkar, Pakistan during the period from 1975 to 2004 were utilized in the present study. Average values for birth weight, weights at 60 and 90 days of age, weaning weight and preweaning average daily gain were 4.11 ± 0.82, 11.58 ± 3.57, 14.92 ± 4.56, 18.95 ± 4.56 and 0.12 ± 0.04 kg, respectively. Coefficients of inbreeding ranged from 10.15 to 37.50 percent for 295 animals, being 1.70 percent of the flock. Inbreeding significantly (P<0.01) affected birth and 60 days weight. Birth weight and 60 days weight decreased by 0.051 and 0.048 kg for each 1 percent increase in the level of inbreeding. However, inbreeding had non significant effect on weight at 90 days of age, weaning weight and preweaning average daily gain. The regression values for these traits were 0.010, 0.083 and 0.105, respectively. It was concluded that inbreeding showed deleterious effects only in early stages of life but as the lambs grew older the effect of inbreeding on pre-weaning traits diminished.

Effect of inbreeding in pre-weaning growth traits Thalli sheep.

Mobile Ad hoc Networks (MANETs) are attracting attention for their potential use in several fields such as collaborative computing and multimedia communications. MANET nodes cooperate in an autonomous way by forwarding packets to each-other. Considering mobility of the terminals, the routes change dynamically so routing algorithms are very important for operation of MANETs. In this paper, we analyse the performance of a MANET by simulations, considering Random Waypoint Mobility (RWM) model. We consider the case when source and destination nodes are static and the other nodes are in continuous mobility. We evaluate the performance by measuring the number of hops and throughput of one-flow traffic. From results, we understand that density and moving speed makes routes more unstable, thus presenting oscillations in number of hops and throughput.

Simulation Performance of a MANET Using Static Source and Destination Considering AODV Routing Protocol

Abstract In this paper exact solutions corresponding to the rotational flow of a fractional Oldroyd-B fluid, in an annulus, are determined by applying integral transforms. The fluid starts moving after t = 0+ when pipes start rotating about their axis. The final solutions are presented in the form of usual Bessel and hypergeometric functions, true for initial and boundary conditions. The limiting cases for the solutions for ordinary Oldroyd-B, fractional Maxwell and Maxwell and Newtonian fluids are obtained. Moreover, the solution is obtained for the fluid when one pipe is rotating and the other one is at rest. At the end of this paper some characteristics of fluid motion, the effect of the physical parameters on the flow and a correlation between different fluid models are discussed. Finally, graphical representations confirm the above affirmation.

https://www.degruyter.com/downloadpdf/j/phys.2018.16.issue-1/phys-2018-0028/phys-2018-0028.xml

Muhammad Younas

Papers

A Generic Approach to the Services Delivery in Enterprise eBusiness Platforms

Mo-Inefficient Wheat Response Toward Molybdenum Supply in Terms of Soil Phosphorus Availability

Effect of inbreeding in pre-weaning growth traits Thalli sheep.

Simulation Performance of a MANET Using Static Source and Destination Considering AODV Routing Protocol

Unsteady flow of fractional Oldroyd-B fluids through rotating annulus