Engineering and Information Technology Collected Works - Research Publications
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ItemNo Preview AvailablePreface( 2017-01-01)
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ItemTowards the development of a simulator for investigating the impact of people management practices on retail performance(Palgrave Macmillan, 2014)Models to understand the impact of management practices on retail performance are often simplistic and assume low levels of noise and linearity. Of course, in real life, retail operations are dynamic, nonlinear and complex. To overcome these limitations, we investigate discrete-event and agent-based modeling and simulation approaches. The joint application of both approaches allows us to develop simulation models that are heterogeneous and more life-like, though poses a new research question: When developing such simulation models one still has to abstract from the real world, however, ideally in such a way that the ‘essence’ of the system is still captured. The question is how much detail is needed to capture this essence, as simulation models can be developed at different levels of abstraction. In the literature the appropriate level of abstraction for a particular case study is often more of an art than a science. In this paper, we aim to study this question more systematically by using a retail branch simulation model to investigate which level of model accuracy obtains meaningful results for practitioners. Our results show the effects of adding different levels of detail and we conclude that this type of study is very valuable to gain insight into what is really important in a model.
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ItemThe importance of the socially-conscious engineer(GHD Digital, 2020)
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ItemTowards the development of a simulator for investigating the impact of people management practices on retail performance(Palgrave Macmillan UK, 2014)Models to understand the impact of management practices on retail performance are often simplistic and assume low levels of noise and linearity. Of course, in real life, retail operations are dynamic, nonlinear and complex. To overcome these limitations, we investigate discrete-event and agent-based modeling and simulation approaches. The joint application of both approaches allows us to develop simulation models that are heterogeneous and more life-like, though poses a new research question: When developing such simulation models one still has to abstract from the real world, however, ideally in such a way that the ‘essence’ of the system is still captured. The question is how much detail is needed to capture this essence, as simulation models can be developed at different levels of abstraction. In the literature the appropriate level of abstraction for a particular case study is often more of an art than a science. In this paper, we aim to study this question more systematically by using a retail branch simulation model to investigate which level of model accuracy obtains meaningful results for practitioners. Our results show the effects of adding different levels of detail and we conclude that this type of study is very valuable to gain insight into what is really important in a model.
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ItemArtificial immune systems(Springer US, 2014-01-01)The biological immune system is a robust, complex, adaptive system that defends the body from foreign pathogens. It is able to categorize all cells (or molecules) within the body asself or nonself substances. It does this with the help of a distributed task force that has theintelligence to take action from a local and also a global perspective using its network of chemical messengers for communication. There are two major branches of the immune system. The innate immune system is an unchanging mechanism that detects and destroys certain invading organisms, whilst the adaptive immune system responds to previously unknown foreign cells and builds a response to them that can remain in the body over a long period of time. This remarkable information processing biological system has caught the attention of computer science in recent years.
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ItemInvestigating the effectiveness of Variance Reduction Techniques in Manufacturing, Call Center and Cross-docking Discrete Event Simulation Models(Springer Berlin Heidelberg, 2012)Variance reduction techniques have been shown by others in the past to be a useful tool to reduce variance in Simulation studies. However, their application and success in the past has been mainly domain specific, with relatively little guidelines as to their general applicability, in particular for novices in this area. To facilitate their use, this study aims to investigate the robustness of individual techniques across a set of scenarios from different domains. Experimental results show that Control Variates is the only technique which achieves a reduction in variance across all domains. Furthermore, applied individually, Antithetic Variates and Control Variates perform particularly well in the Cross-docking scenarios, which was previously unknown.
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ItemEvaluating different cost-benefit analysis methods for port security operations(CRC Press, 2012-01-01)
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ItemThe Dendritic Cell Algorithm for Intrusion Detection(Bio-Inspired Communications and Networking, IGI Global, 2011)As one of the solutions to intrusion detection problems, Artificial Immune Systems (AIS) have shown their advantages. Unlike genetic algorithms, there is no one archetypal AIS, instead there are four major paradigms. Among them, the Dendritic Cell Algorithm (DCA) has produced promising results in various applications. The aim of this chapter is to demonstrate the potential for the DCA as a suitable candidate for intrusion detection problems. We review some of the commonly used AIS paradigms for intrusion detection problems and demonstrate the advantages of one particular algorithm, the DCA. In order to clearly describe the algorithm, the background to its development and a formal definition are given. In addition, improvements to the original DCA are presented and their implications are discussed, including previous work done on an online analysis component with segmentation and ongoing work on automated data pre-processing. Based on preliminary results, both improvements appear to be promising for online anomaly-based intrusion detection.
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ItemArtificial Immune Systems(Springer Verlag, 2010)
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ItemEngineering Principles of Ultrasound Technology(Elsevier, 2017-07-01)The book also contains how the technology could be launched in industry. Part I discusses ultrasound for food preservation, with topics like advances on thermo-sonication and nanothermosonication. This Chapter describes how ultrasonic waves are formed in ultrasonic baths, with horn transducers and in other acoustic devices. The range of acoustic frequencies and powers relevant to sonoprocessing are outlined. The concept of acoustic cavitation is explained as the formation of a field of small bubbles within a liquid exposed to ultrasound. It is the repetitive collapse of these bubbles under the influence of the acoustic field that is the dominant cause of most effects used in food processing, as it causes fluid turbulence and microjetting. The extent to which it is effective is a function of the system temperature and pressure, as well as fluid properties such as the surface tension, density and viscosity. The concept of acoustic nebulisation, which is the formation of a fine mist, is also explained.