Richard E. Overill

Design of an artificial immune system as a novel anomaly detector for combating financial fraud in the retail sector

The retail sector often does not possess sufficient knowledge about potential or actual frauds. This requires the retail sector to employ an anomaly detection approach to fraud detection. To detect anomalies in retail transactions, the fraud detection system introduced in this work implements various salient features of the human immune system. This novel artificial immune system, called CIFD (computer immune system for fraud detection), adopts both negative selection and positive selection to generate artificial immune cells. CIFD also employs an analogy of the self-major histocompatability complex (MHC) molecules when antigen data is presented to the system. These novel mechanisms are expected to improve the scalability of CIFD, which is designed to process gigabytes or more of transaction data per day. In addition, CIFD incorporates other prominent features of the HIS such as clonal selection and memory cells, which allow CIFD to behave adaptively as transaction patterns change.

Detection of known and unknown DDoS attacks using Artificial Neural Networks

The key objective of a Distributed Denial of Service (DDoS) attack is to compile multiple systems across the Internet with infected zombies/agents and form botnets of networks. Such zombies are designed to attack a particular target or network with different types of packets. The infected systems are remotely controlled either by an attacker or by self-installed Trojans (e.g. roj/Flood-IM) that are programmed to launch packet floods. Within this context, the purpose of this paper is to detect and mitigate known and unknown DDoS attacks in real time environments. We have chosen an Artificial Neural Network (ANN) algorithm to detect DDoS attacks based on specific characteristic features (patterns) that separate DDoS attack traffic from genuine traffic.

The orbital diamagnetic contribution to nuclear spin—spin coupling constants in the first- and second-row hydrides: An AB initio study

Abstract Ab initio calculations of the orbital diamagnetic contributions to nuclear spin—spin coupling constants in the first- and second-row hydrides have be

Heterogeneous computing machines and Amdahl's law

Abstract We consider the implications of Amdahls Law for a heterogeneous system of computers each of which is a homogeneous parallel processor. We introduce a parallelism profile function to describe the level of parallelism achieved in different fragments of the computation and demonstrate that, for some choices of this function, the performance of a heterogeneous system significantly exceeds that of each of the component homogeneous systems.

Evaluation of Evidence in Internet Auction Fraud Investigations

Internet auction fraud has become prevalent. Methodologies for detecting fraudulent transactions use historical information about Internet auction participants to decide whether or not a user is a potential fraudster. The information includes reputation scores, values of items, time frames of various activities and transaction records. This paper presents a distinctive set of fraudster characteristics based on an analysis of 278 allegations about the sale of counterfeit goods at Internet auction sites. Also, it applies a Bayesian approach to analyze the relevance of evidence in Internet auction fraud cases.

Sensitivity Analysis of Bayesian Networks Used in Forensic Investigations

Research on using Bayesian networks to enhance digital forensic investigations has yet to evaluate the quality of the output of a Bayesian network. The evaluation can be performed by assessing the sensitivity of the posterior output of a forensic hypothesis to the input likelihood values of the digital evidence. This paper applies Bayesian sensitivity analysis techniques to a Bayesian network model for the well-known Yahoo! case. The analysis demonstrates that the conclusions drawn from Bayesian network models are statistically reliable and stable for small changes in evidence likelihood values.

The uracil–fluoride interaction: ab initio calculations including solvation

Ab initio calculations show that a uracil–fluoride complex is thermodynamically stable even when hydrated, and the implications of this finding for nucleic acid biochemistry briefly discussed.

Ab initio studies of the strongest type of hydrogen bond: carboxylic acid–fluoride systems

Ab initio LCAO–MO–SCF calculations have been performed on the acetic acid–fluoride system and the strength of the hydrogen bond, MeCO2H ⋯ F–, is found to be as strong as that previously reported for the formic acid–fluoride system. The implications of this and its relationship to other physical parameters of these hydrogen bonds are discussed. The carboxylic acid–fluoride systems are capable of forming esters with simple alkyl halides. The enhanced nucleophilicity of RCO2H has been shown to be due to the increased negative charge of the hydroxy oxygen atom induced by the formation of the very strong hydrogen bond to the fluoride ion.

Insider threats in corporate environments: a case study for data leakage prevention

Regardless of the established security controls that organizations have put in place to protect their digital assets, a rise in insider threats has been observed and particularly in incidents of data leakage. The importance of data as corporate assets is leading to a growing need for detection, prevention and mitigation of such violations by the organisations. In this paper we are investigating the different types of insider threats and their implications to the corporate environment, with specific emphasis to the special case of data leakage. Organisations should evaluate the risk they are facing due to insider threats and establish proactive measures towards this direction. In response to the challenging problem of identifying insider threats, we design a forensic readiness model, which is able to identify, prevent and log email messages, which attempt to leak information from an organisation with the aid of steganography.

Computational studies of the electroweak origin of biomolecular handedness in natural sugars

The violation of parity by the weak interactions ensures that enantiomeric chiral molecules have inequivalent energies. These parity violating energy differences have been calculated, using ab initio methods, for the biologically important sugars deoxyribose, ribose, arabinose, xylose and lyxose. It is found that in each case the choice of which enantiomer is of lower energy is dependent on the molecular conformation adopted, particularly the type of furanose ring pucker. In general the D-enantiomers are favoured for molecules having a C2-endo pucker, whereas the L-series are preferred for C3-endo puckers. The significance of these energy differences for the transition from a prebiotic racemic geochemistry to a homochiral biochemistry in terrestrial evolution is discussed.