Publications

by Alan Holt 

Peer Review Journals

  • Monitoring Large Management Domains with Mobile Agents, Mediterranean Journal of Computers and Networks. Volume 4, Number 1, January 2008, pages 13-19.

    In this paper, we consider the use of Mobile Agent (MA) technology for managing large domains of networked devices. We present a performance analysis of mobile agents in a distributed network environment. In particular we consider both reliable (such as wired Ethernet networks) and an unreliable network environments (such as wireless networks). The performance of MAs directly affects their ability to monitor the management domain. Measurement readings of the domain state are only useful if they can be collected and delivered to management stations in a timely manner. In this paper, MA performance is analysed as a function domain size. Moreover, methods for improving MA performance in large domains are investigated.

  • Performance analysis of mobile agents.  IET Communications – Proceedings, 2007.
    Click here for preprint. 
    The results of a performance analysis of mobile agents in a distributed network environment are presented. Analytical models are developed and used to compare the performance of carrying out a simple management function with mobile agents (MA) or SNMP (simple network management protocol). An examination is made of how delay is affected by the size of the management domain and how each method behaves in both a local area network (LAN) and wide area network (WAN) environment. For large domains, optimal performance is obtained if the mobile agents' size is bounded, and this may require sharing the management task among a small number of mobile agents.
  • World-Wide Web mirrors: likelihood of stale content. IET Electronics Letters 2006.
    Mirroring is common practice for popular sites. Geographically distributed mirrors help to load-balance network traffic. Furthermore, content downloads are faster for users accessing a nearby mirror. Users, however, may value up-to-date content over performance and network optimality, so it is important to ensure that revisions are propagated to mirrors regularly. Triggered or frequently scheduled updates can place heavy loads on the network. Furthermore, content providers may wish to schedule mirror updates during off-peak times in order to take advantage of less than best effort services. The trade-off between update frequencies of mirror sites and the likelihood of stale content is explored
  • An integrated manufacturing network management framework by using mobile agent. International Journal of Advanced Manufacturing Technology 2006.
    The growth in the development of distributed manufacturing systems necessitates increases in efficient technologies in order to facilitate management of the networked resources. Systems such as manufacturing automation protocol (MAP) already exist which were specifically designed for managing networked manufacturing devices. However, MAP has been criticised for being over-complex and expensive for small–medium sized enterprises. The simple network management protocol (SNMP) was designed for managing TCP/IP networks, and we argue that it can also be used for managing networked manufacturing devices. However, SNMP, like MAP, is based upon a client/server architecture, and both have scalability issues. We also investigate the use of mobile agent (MA) technology as a means of managing a domain of manufacturing devices. An integrated network management framework based on MA technology is developed to direct the research into the investigation of aligning network management paradigm to the strategic management decision.
  • The application of dependency management in an integrated manufacturing network. International Journal of Advanced Manufacturing Technology 2006.
    Research into the effectiveness and performance of the mobile agent (MA) technology as a means of managing a domain of manufacturing devices has been conducted. However, it has been shown that MAs are not without their scalability issues. A strategic agent travelling algorithm will bring performance improvement as it allows agents to identify the best migration path in order to minimise the total expected time of searching for the desired information. The applications of process-driven dependency management along with MA techology are examined as methods for optimising the efficiency of retrieving critical information in the manufacturing environment. An integrated framework is developed to investigate the alignment of network management paradigm to the strategic management decision.
  • Theoretical performance analysis of mirroring World Wide Web sites. IEE Proceedings – Communications 2003.
    Popular World Wide Web sites can often cause congestion hot spots in the network, resulting in degradation of performance. Typically, such sites are mirrored in order to alleviate bottlenecks. This presents users of these sites with a choice of where to access their documents. Using a theoretical Web access delay model, a performance analysis is carried out which shows the effects of mirror location and communication facility speed. The analysis shows the conflict of interest between the network operator trying to optimise aggregate data rates and that of the users trying to maximise their own individual data rates. The results reflect upon the load balancing policies for optimal network performance.
  • Long-range dependence and self-similarity in World Wide Web proxy cache references. IEE Proceedings – Communications 2000.
    The existence of long-range dependence and self-similarity properties within World Wide Web proxy cache references is reported. Fractional ARIMA processes are used to generate long-range dependent cache hit/miss sequences in order to model the growth in cache occupancy. This model was compared to a model using independent cache hit/miss sequences and it was found that the results predicted by these models differed significantly. However, the results of the fractional ARIMA model resembled the growth of an actual cache. Trace simulations were carried out in order to investigate the effects of long-range dependence and self-similarity on cache replacement and garbage collection policies

Books

  • 802.11 Network, building, analysing and securing. To be published by Springer.
  • Network Performance Analysis using the J Programming Language. Springer 2007. introduces the J programming language and how it can be used to carry network performance analysis. Covers network calculus, simulation, Internet congestion control, ATM quality of service and methods of modeling network traffic.
  • Network Application From Hell. chapter in Social and Ethical Effects of the Computer Revolution, McFarland, 1996. Discusses the impact of the World-Wide Web on the current network infrastructure.

Magazines

  • Python generators. To be published in Linux Journal.
  • Controlling Input/Output of Device Drivers. Linux Magazine, March 2008. Hands-on tutorial for monitoring and configuring I/O for network device drivers at the Kernel level. Here are the Source code listings.
  • DCCP: Internet Congestion Control for Real-time Applications.Linux Magazine, November 2007. DCCP is a new Internet transport layer. It is a connectionless protocol, with congestion control. An application, written in C, is presented in order to demonstrate the protocol.
  • Multicasting. Sys Admin Magazine, November 2006.This paper describes multicast  protocols and algorithms. A simple multicast application, written in C, is presented.
  • Automating the Management of Network Devices through the Command Line. Sys Admin Magazine, March 2007. Presents a set of Python modules accessing communications devices through the command-line. Telneting through SSH tunnels gives secure access to devices, even over the Internet.
  • Prisoners, chickens, volunteers, free riders and suckers: dilemmas on the Internet, IEE Engineering, Science and Education Journal, April 1997. This paper uses game theory to analyse the performance of computer networks.
    The World Wide Web enables users to access a variety of multimedia resources distributed around the world. Its ease of use has attracted many new users to the Internet and the emergence of commercial Internet providers has facilitated this growth. Although most people welcome the breakdown of elitist access to the Internet, it has had an impact on the performance experienced by the individual user. `Game theory' is used to examine the conflict of self interest versus group interest within a shared network environment like the Internet.

Conferences

Press Articles (Waikato Times)

  • Grid computing
  • From Unix to Linux
  • Wirless security
  • Law of averages
  • Open source