Energy-efficient wireless communication

In this chapter we present an energy-efficient highly adaptive network interface architecture and a novel data link layer protocol for wireless networks that provides Quality of Service (QoS) support for diverse traffic types. Due to the dynamic nature of wireless networks, adaptations in bandwidth scheduling and error control are necessary to achieve energy efficiency and an acceptable quality of service. In our approach we apply adaptability through all layers of the protocol stack, and provide feedback to the applications. In this way the applications can adapt the data streams, and the network protocols can adapt the communication parameters

Energy-efficient adaptive wireless network design

Energy efficiency is an important issue for mobile computers since they must rely on their batteries. We present an energy-efficient highly adaptive architecture of a network interface and novel data link layer protocol for wireless networks that provides quality of service (QoS) support for diverse traffic types. Due to the dynamic nature of wireless networks, adaptations are necessary to achieve energy efficiency and an acceptable quality of service. The paper provides a review of ideas and techniques relevant to the design of an energy efficient adaptive wireless networ

Quality of Service over Specific Link Layers: state of the art report

The Integrated Services concept is proposed as an enhancement to the current Internet architecture, to provide a better Quality of Service (QoS) than that provided by the traditional Best-Effort service. The features of the Integrated Services are explained in this report. To support Integrated Services, certain requirements are posed on the underlying link layer. These requirements are studied by the Integrated Services over Specific Link Layers (ISSLL) IETF working group. The status of this ongoing research is reported in this document. To be more specific, the solutions to provide Integrated Services over ATM, IEEE 802 LAN technologies and low-bitrate links are evaluated in detail. The ISSLL working group has not yet studied the requirements, that are posed on the underlying link layer, when this link layer is wireless. Therefore, this state of the art report is extended with an identification of the requirements that are posed on the underlying wireless link, to provide differentiated Quality of Service

The role of IT/IS in combating fraud in the payment card industry

The vast growth of the payment card industry (PCI) in the last 50 years has placed the industry in the centre of attention, not only because of this growth, but also because of the increase of fraudulent transactions. The conducted research in this domain has produced statistical reports on detection of fraud, and ways of protection. On the other hand, the relevant body of research is quite partial and covers only specific topics. For instance, the provided reports related to losses due to fraudulent usage of cards usually do not present the measures taken to combat fraud nor do they explain the way fraud happens. This can turn out to be confusing and makes one believe that card usage can be more negative than positive. This paper is intended to provide accumulative and organized information of the efforts made to protect businesses from fraud. We try to reveal the effectiveness and efficiency of the current fraud combating techniques and show that organized worldwide efforts are needed to take care of the larger part of the problem. The research questions that will be addressed in the paper are: 1) how can IT/IS help in combating fraud in the PCI?, and 2) is the implemented IT/IS effective and efficient enough to bring progress in combating fraud? Our research methodology is based on a case study conducted in a Macedonian bank. The research is explorative and will be mostly qualitative in nature; however some quantitative aspects will be included. The findings indicate that fraud can take up many forms. A classification of the different forms of data theft into different fraudulent appearances was made. We showed that the benefits from implementing the fraud reduction efforts are multiple. Results show that a bank has to be very small to experience losses from fixed expenditures coming from the implementation of the fraud reduction IT/IS. Medium-sized and large banks should not even see any problems arising from those expenditures. Based on the empirical data and the presented facts we can conclude that the fraud reduction IT/IS do have a positive effect on all sides of the payment process and fulfills the expectations of all stakeholders

A methodological approach to BISDN signalling performance

Sophisticated signalling protocols are required to properly handle the complex multimedia, multiparty services supported by the forthcoming BISDN. The implementation feasibility of these protocols should be evaluated during their design phase, so that possible performance bottlenecks are identified and removed. In this paper we present a methodology for evaluating the performance of BISDN signalling systems under design. New performance parameters are introduced and their network-dependent values are extracted through a message flow model which has the capability to describe the impact of call and bearer control separation on the signalling performance. Signalling protocols are modelled through a modular decomposition of the seven OSI layers including the service user to three submodels. The workload model is user descriptive in the sense that it does not approximate the direct input traffic required for evaluating the performance of a layer protocol; instead, through a multi-level approach, it describes the actual implications of user signalling activity for the general signalling traffic. The signalling protocol model is derived from the global functional model of the signalling protocols and information flows using a network of queues incorporating synchronization and dependency functions. The same queueing approach is followed for the signalling transfer network which is used to define processing speed and signalling bandwidth requirements and to identify possible performance bottlenecks stemming from the realization of the related protocols

A Framework for Quality-Driven Delivery in Distributed Multimedia Systems

In this paper, we propose a framework for Quality-Driven Delivery (QDD) in distributed multimedia environments. Quality-driven delivery refers to the capacity of a system to deliver documents, or more generally objects, while considering the users expectations in terms of non-functional requirements. For this QDD framework, we propose a model-driven approach where we focus on QoS information modeling and transformation. QoS information models and meta-models are used during different QoS activities for mapping requirements to system constraints, for exchanging QoS information, for checking compatibility between QoS information and more generally for making QoS decisions. We also investigate which model transformation operators have to be implemented in order to support some QoS activities such as QoS mapping