The current strategy to computer networking is to increase the accessibility that legitimate users have to their respective systems and to distribute functionality. This creates a more efficient working environment, users may work from home, organisations can make better use of their computing power. Unfortunately, a side effect of opening up computer systems and placing them on potentially global networks is that they face increased threats from uncontrolled access points, and from eavesdroppers listening to the data communicated between systems. Along with these increased threats the traditional ones such as disgruntled employees, malicious software, and accidental damage must still be countered. A comprehensive integrated security system ( CISS ) has been developed to provide security within the Open Systems Interconnection (OSI) and Open Distributed Processing (ODP) environments. The research described in this thesis investigates alternative methods for its implementation and its optimisation through partial implementation within hardware and software and the investigation of mechanismsto improve its security. A new deployment strategy for CISS is described where functionality is divided amongst computing platforms of increasing capability within a security domain. Definitions are given of a: local security unit, that provides terminal security; local security servers that serve the local security units and domain management centres that provide security service coordination within a domain. New hardware that provides RSA and DES functionality capable of being connected to Sun microsystems is detailed. The board can be used as a basic building block of CISS, providing fast cryptographic facilities, or in isolation for discrete cryptographic services. Software written for UNIX in C/C++ is described, which provides optimised security mechanisms on computer systems that do not have SBus connectivity. A new identification/authentication mechanism is investigated that can be added to existing systems with the potential for extension into a real time supervision scenario. The mechanism uses keystroke analysis through the application of neural networks and genetic algorithms and has produced very encouraging results. Finally, a new conceptual model for intrusion detection capable of dealing with real time and historical evaluation is discussed, which further enhances the CISS concept.

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This research defines a new information-centric networking (ICN) framework and associated protocol that is implementable in the existing internet with feasible minimal changes to the existing internet infrastructure. We create a protocol that assigns globally unique data item names and embeds these names, plus associated metadata, into an IPv6 header. This technique allows the use of the existing IPsec suite of protocols to mitigate user privacy and security concerns which exist in other existing non-implementable ICN designs. We demonstrate that this technique allows the use of standard routing and switching methods, which ensures network stability and reachability, and it permits self-assembly into internetworks. Next, we analyze the layer four functionality which must be provided by a general-purpose transport protocol, and we give an initial implementation which is used by our prototype. Lastly, using the Mininet network virtualization suite, we show that using RFC-compliant IPv6 datagrams as the named content allows information-centric routing and switching to be done using unmodified hardware and software, and that it also ensures backwards compatibility with unmodified networks.

With the emergence of advanced integrated services networks, the need for effective performance analysis techniques has become extremely important. Further advancements in these networks can only be possible if the practical performance issues of the existing networks are clearly understood. This thesis is concerned with the design and development of a measurement system which has been implemented on a large experimental network. The measurement system is based on dedicated traffic generators which have been designed and implemented on the Project Unison network. The Unison project is a multisite networking experiment for conducting research into the interconnection and interworking of local area network based multi-media application systems. The traffic generators were first developed for the Cambridge Ring based Unison network. Once their usefulness and effectiveness was proven, high performance traffic generators using transputer technology were built for the Cambridge Fast Ring based Unison network. The measurement system is capable of measuring the conventional performance parameters such as throughput and packet delay, and is able to characterise the operational performance of network bridging components under various loading conditions. In particular, the measurement system has been used in a 'measure and tune' fashion in order to improve the performance of a complex bridging device. Accurate measurement of packet delay in wide area networks is a recognised problem. The problem is associated with the synchronisation of the clocks between the distant machines. A chronological timestamping technique has been introduced in which the clocks are synchronised using a broadcast synchronisation technique. Rugby time clock receivers have been interfaced to each generator for the purpose of synchronisation. In order to design network applications, an accurate knowledge of the expected network performance under different loading conditions is essential. Using the measurement system, this has been achieved by examining the network characteristics at the network/user interface. Also, the generators are capable of emulating a variety of application traffic which can be injected into the network along with the traffic from real applications, thus enabling user oriented performance parameters to be evaluated in a mixed traffic environment. A number of performance measurement experiments have been conducted using the measurement system. Experimental results obtained from the Unison network serve to emphasise the power and effectiveness of the measurement methodology.

Since the introduction of the Internet and the realisation of its potential companies have either transformed their operation or are in the process of doing so. It has been observed, that developments in I.T., telecommunications and the Internet have boosted the number of enterprises engaging into e-commerce, e-business and virtual enterprising. These trends are accompanied by re-shaping, transformation and changes in an enterprise's boundaries. The thesis gives an account of the research into the area of dynamic enterprise modelling and provides a modelling methodology that allows different roles and business models to be tested and evaluated without the risk associated with committing to a change.

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An automated signal classifier and a semi-automated signal identifier are designed for collecting the dielectrophoretic signatures of cells flowing through a dielectrophoretic cytometer. In past work, the DEP cytometer signals were manually sorted by going through all recorded signals, which is impractical when analyzing 1000’s of cells per day. In the semi-automated method of collection, signals are automatically identified as events and displayed on the user interface to be accepted or rejected by the user. This approach reduced signal collection time by more than half and produced statistics nearly identical to the manual method. The automated signal classifier based on pattern recognition categorizes detection signals as ‘Accept’ or ‘Reject’. Analyzing large volumes of detection signals is possible in much reduced times and may be approaching real time capability.

As VLSI fabrication technology scales, an increasing number of processing elements (cores) on a chip makes on-chip communication a new performance bottleneck. The Network-on-Chip (NoC) paradigm has emerged as an efficient and scalable infrastructure to handle the communication needs for such multi-core systems. In most existing NoCs, design decisions are made assuming that the NoC operates at the same or lower clock speed as the cores, which slows down the communication system. A major challenge in designing a high speed NoC is the difficulty of distributing a high speed, low power clock across the chip. In this dissertation, we first propose several techniques to address the issue of distributing a high-speed, low power, low jitter clock across the IC. We primarily focus our attention on resonant standing wave oscillators (SWOs), which have recently emerged as a promising technique for high-speed, low power clock generation. In addition, we also present a dynamic programming based approach to synthesize a low jitter, low power buffered H-tree for clock distribution. In the second part of this dissertation, we use these efficient clock distribution schemes to present a novel fast NoC design that relies on source synchronous data transfer over a ring. In our source-synchronous design, the clock and data NoC are routed in parallel yielding a fast, robust design. Architectural simulations on synthetic and real traffic show that our source-synchronous NoC designs can provide significantly lower latency while achieving the same or better bandwidth compared to a state of the art mesh, while consuming lower area. The fact that the our ring-based NoC runs significantly faster than the mesh contributes to these improvements. Moreover, since our proposed NoC designs are fully synchronous, they are very amenable to testing as well. In the last part of this dissertation, we explore an alternate scheme of achieving high-speed on-chip data transfer using sinusoidal signals of different frequencies. The key advantage of our method is the ability to superimpose such sinusoids and thereby effectively send multiple logic values along the same wire in a clock cycle. Experimental results show that for the same throughput as that of a traditional scheme, we require significantly fewer wires.

Chip Multi-Processor (CMP) architectures have become mainstream for designing processors. With a large number of cores, Network-On-Chip (NOC) provides a scalable communication method for CMP architectures. NOC must be carefully designed to meet constraints of power and area, and provide ultra low latencies and high throughput. In this research, we explore different techniques to design high performance NOC. First, existing NOCs mostly use Dimension Order Routing (DOR) to determine the route taken by a packet in unicast traffic. However, with the development of diverse applications in CMPs, one-to-many (multicast) and one-to-all (broadcast) traffic are becoming more common. Current unicast routing cannot support multi-cast and broadcast traffic efficiently. We propose Recursive Partitioning Multicast (RPM) routing and a detailed multicast wormhole router design for NOCs. RPM allows routers to select intermediate replication nodes based on the global distribution of destination nodes. This provides more path diversities, thus achieves more bandwidth-efficiency and finally improves the performance of the whole network. Second, as feature size is shrinking, wires are becoming abundant resources available in NOC. Since NOC can benefit from high wire density due to no limits on the number of pins and faster signaling rates, it is very critical in the NOC router design to find a way that fully utilizes the wire resources to provide high performance. We propose an Adaptive Physical Channel Regulator (APCR) for NOC routers to exploit huge wiring resources. The flit size in an APCR router is less than the physical channel width (phit size) to provide finer granularity flow control. An APCR router allows flits from different packets or flows to share the same physical channel in a single cycle. The three regulation schemes (Monopolizing, Fair-sharing and Channel-stealing) intelligently allocate the output channel resources considering not only the availability of physical channels but the occupancy of input buffers. In an APCR router, each Virtual Channel can forward a dynamic number of flits every cycle depending on the run-time network status. Third, nanophotonics has been proposed to design low latency and high band- width NOC for future CMPs. Recent nanophotonic NOC designs adopt the token- based arbitration coupled with credit-based flow control, which leads to low band- width utilization. We propose two handshake schemes for nanophotonic interconnects in CMPs, Global Handshake (GHS) and Distributed Handshake (DHS), which get rid of the traditional credit-based flow control, reduce the average token waiting time, and finally improve the network throughput. Furthermore, we enhance the basic handshake schemes with setaside buffer and circulation techniques to overcome the Head-Of-Line (HOL) blocking.

This research explored the phenomenon of online social network in the context of consumer-brand relationship. The specific research objectives were: (a) to examine whether perceived benefits of a Brand’s Social Network Website (BSN) predict BSN relationship quality; (b) to investigate whether perceived benefits of BSN predict perceived relationship investment; (c) to examine if online social connection strengthens the relationship between perceived benefits of BSN and BSN relationship quality; (d) to examine if experience with BSN strengthens the relationship between perceived benefits of BSN and BSN relationship quality; (e) to investigate whether BSN relationship quality predicts brand relationship quality; (f) to examine whether BSN relationship quality predicts customer loyalty toward BSN; (g) to investigate whether perceived relationship investment predicts brand relationship quality; (h) to investigate whether brand relationship quality predicts customer loyalty toward BSN; (i) to examine whether brand relationship quality predicts customer loyalty toward the brand; and (j) to investigate whether customer loyalty toward BSN predicts customer loyalty toward the brand. This research employed a mixed-method approach to overcome the weaknesses in a single method approach and to provide stronger evidence for a conclusion. First, qualitative analyses explored the unique context of BSN, which was not much investigated in prior research. Specifically, Brand Pages of 22 apparel brands and 10 restaurant/coffeehouse brands, chosen as research settings, were investigated to validate the proposed research constructs. Second, quantitative analyses utilized an online self-administered cross-sectional survey method. A total of 501 complete responses collected from consumer panels of marketing research firm were used. The results suggested that BSN benefits are important drivers of relationship mediators (i.e., BSN relationship quality, perceived relationship investment), which in turn positively influence BRQ. However, functional benefits did not influence BSN relationship quality. In addition, while customer loyalty toward BSN was predicted by both BSN relationship quality and BRQ, it did not positively influence the loyalty toward the brand. Specifically, BSN loyalty did not influence behavioral loyalty and negatively influenced willingness to pay price premium. Further discussion about the results, implications, and suggestions for future research were provided.