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

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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 area of information technology continues to experience considerable progress and innovation in recent years. Computers have evolved from large and very expensive devices, to mainstream products we take for granted in our everyday lives. Increasingly, cloud-based services have come to the fore. Additionally, many people own multiple computing devices, from normal desktop computers to small mobile devices. We find mobile computing devices of particularly interest and this will be the focus of our study. In this chapter, we investigate a context-aware and cloud-based adaptation of mobile devices and user’s experience. Our research displays new and novel contribution to the area of context-awareness in the cloud setup. We propose and demonstrated principles in implemented applications, whereby context-aware information is harvested from several dimensions to build a rich foundation for context-aware computation. Furthermore, we have exploited and combined this with the area of cloud computing technology to create a new user experience and a new way to invoke control over user’s mobile phone. Through a developed application suite with the following evaluation, we have shown the feasibility of such an approach. Moreover, we believe our research, incorporating remote, and automatically configuration of Android phone advances the research area of context-aware information.

Automatic Configuration of Mobile Applications Using Context-Aware Cloud-Based Services

We investigated context-awareness by utilising multiple sources of context in a mobile device setting. In our experiment we developed a system consisting of a mobile client, running on the Android platform, integrated with a cloud-based service. These components were integrated using push messaging technology. One of the key features was the automatic adaptation of smartphones in accordance with implicit user needs. The novelty of our approach consists in the use of multiple sources of context input to the system, which included the use of calendar data and web based user configuration tool, as well as that of an external, cloud-based, configuration file storing user interface preferences which, pushed at log-on time irrespective of access device, frees the user from having to manually configure its interface. The system was evaluated via two rounds of user evaluations (n = 50 users), the feedback of which was generally positive and demonstrated the viability of using cloud-based services to provide an enhanced context-aware user experience.

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Every Cloud Has a Push Data Lining: Incorporating Cloud Services in a Context-Aware Application

Modern E-commerce services are offered in a flexible but complex setup involving multiple websites, for example, business web portals or price comparison websites, which are used in drawing the prices of a variety of online products from related websites and presenting them to millions of customers. Though this modern style of service provisioning is very attractive it significantly increases load on the web servers implementing the E-commerce services. The concern is that overloaded servers will become unresponsive and will drop requests which are beyond their capacity. This paper presents a new approach to the synthesis of performance management mechanisms, which we contend, provides more effective way for managing the performance of modern E-commerce services. The proposed approach is formally specified and is implemented as a Java-based prototype system. A number of experiments are conducted in order to test the performance management of the proposed approach.

Synthesis of performance management mechanisms in modern e-commerce services

The Web of today is a mature application consumption and development platform. Web browsers are stable, JavaScript code is almost fully portable among browsers, Web services provide access to an unprecedented amount of reusable functionality on the Web, and Web applications are as interactive and engaging as their desktop counterparts—if not even more. All this is true especially for conventional desktop and notebook computers, while things slightly change if we move our focus from conventional clients to mobile clients, such as mobile phones, smart phones, tablets, embedded devices, and the like, a reality that has been growing considerably over the last years. For instance, already two years ago, there were more mobile users than desktop users accessing social networking applications [1], and the number of mobile phone users is much higher than the number of desktop/notebook users. However, despite extraordinary and fast progress, mobile services and applications are still in their infancy and only seldom at the level of quality of their desktop counterparts. The increasing adoption of standard Web technologies, originally developed for conventional Web clients, significantly eases also the development of services and

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Mobile Web and service applications: guest editors’ introduction

Hidden Web databases maintain a collection of documents, which are dynamically generated using Web page templates in response to user queries This paper presents a technique, Text with Neighbouring Adjacent Tag Segments (TNATS), to represent the contents of documents retrieved from an underlying database TNATS exploits tag structures that surround the textual content of a document This representation facilitates the process of detecting Web page templates and extraction of query-related information from documents We compare the performance of TNATS with existing techniques based on tag tree and text only representations Experimental results demonstrate that TNATS requires less processing time for information extraction than a tag tree representation It also produces optimum results in terms of detecting Web page templates and extracting query-related information.

Muhammad Younas

Papers

Automatic Configuration of Mobile Applications Using Context-Aware Cloud-Based Services

Every Cloud Has a Push Data Lining: Incorporating Cloud Services in a Context-Aware Application

Synthesis of performance management mechanisms in modern e-commerce services

Mobile Web and service applications: guest editors’ introduction

A TNATS approach to hidden web documents