Transferability of Intrusion Detection Systems Using Machine Learning between Networks

Intrusion detection systems (IDS) using machine learning is a next generation tool to strengthen the cyber security of networks. Such systems possess the potential to detect zero-day attacks, attacks that are unknown to researchers and are occurring for the first time in history. This thesis tackles novel ideas in this research domain and solves foreseeable issues of a practical deployment of such tool. The main issue addressed in this thesis are situations where an entity intends to implement an IDS using machine learning onto their network, but do not have attack data available from their own network to train the IDS. A solution is to train the IDS using attack data from other networks. However, there is a degree of uncertainty whether this is feasible as different networks use different applications and have different uses. Such IDS may not be able to adequately operate on a network when trained on data from an entirely different network. The proposed methodology in this research recommends the training set should combine attack data collected from other networks with benign traffic which originates from the network the IDS is to be implemented on. This method is compared with a training set which is completely composed of both attack and benign data from a completely different network. The best performing model implemented with both training sets demonstrated the feasibility of both scenarios. Both versions of that model achieved an F1 score of 0.82 and 0.81 respectively, and both versions detected roughly 70% of attacks and 99% of benign traffic. However, most IDSs trained on the former training set listed yielded the best results. The main benefit of training a model on target network benign data is to minimize false positive classifications. The average model witnessed a 113% boost in precision, compared to their counterparts trained on foreign network benign data. Another issue addressed in this thesis is the detection scope of attacks. The IDS scope of detection is limited to the attacks it is trained on. Using the proposed IDS training set, an intuitive feature selection scheme and classification threshold adjustment, this thesis improves the IDS scope of detection to detect attacks outside of its training data. Feature selection can manipulate an IDS to detect specific attacks not included in its training data. Using threshold tuning, the IDSs in this thesis detected up to 200% more attacks. Both issues and solutions are simulated and verified in two separate scenarios using neural networks and random forest

Mosaic Analysis of Precursors of Nerve, Bone and Vasculature in Caudal Body and Fin of Zebrafish

This project focuses on the specific developmental origin and formation of pre-osteoblasts, vascular cells and sensory neurons in the caudal region and tail of zebrafish. Our objective is to generate genetically marked clones using transposon microinjections and to analyze fluorescent protein markers in deep body and tail cell populations. If clones are shared between the fin and deep body it is suggestive that these cells share a common progenitor cell. Zebrafish fins can serve as a model for human organogenesis because conserved genes and cell types are found in human limbs

A general one-step synthesis of alkanethiyl-stabilized gold nanoparticles with control over core size and monolayer functionality

Funding: Engineering and Physical Sciences Research Council - EP/M506631/1, EP/J500549/1, EP/K016342/1; Leverhulme Trust - RPG-2015-042; Army Research Office - W911NF-20-1-0233; University of St Andrews; Fundación para el Fomento en Asturias de la Investigación Científica Aplicada y la Tecnología - AC17-14; European Commission - AC17-14.In spite of widespread interest in the unique size-dependent properties and consequent applications of gold nanoparticles (AuNPs), synthetic protocols that reliably allow for independent tuning of surface chemistry and core size, the two critical determinants of AuNP properties, remain limited. Often, core size is inherently affected by the ligand structure in an unpredictable fashion. Functionalized ligands are commonly introduced using postsynthesis exchange procedures, which can be inefficient and operationally delicate. Here, we report a one-step protocol for preparing monolayer-stabilized AuNPs that is compatible with a wide range of ligand functional groups and also allows for the systematic control of core size. In a single-phase reaction using the mild reducing agent tert-butylamine borane, AuNPs that are compatible with solvents spanning a wide range of polarities from toluene to water can be produced without damaging reactive chemical functionalities within the small-molecule surface-stabilizing ligands. We demonstrate that the rate of reduction, which is easily controlled by adjusting the period over which the reducing agent is added, is a simple parameter that can be used irrespective of the ligand structure to adjust the core size of AuNPs without broadening the size distribution. Core sizes in the range of 2–10 nm can thus be generated. The upper size limit appears to be determined by the nature of each specific ligand/solvent pairing. This protocol produces high quality, functionally sophisticated nanoparticles in a single step. By combining the ability to vary size-related nanoparticle properties with the option to incorporate reactive functional groups at the nanoparticle–solvent interface, it is possible to generate chemically reactive colloidal building blocks from which more complex nanoparticle-based devices and materials may subsequently be constructed.Publisher PDFPeer reviewe

Probing multiscale factors affecting the reactivity of nanoparticle-bound molecules

I. K. M., W. E., E. J. H, S. S. and E. R. K. are grateful for funding from the Leverhulme Trust [RPG-2015-042], the Engineering and Physical Sciences Research Council [EP/K016342/1], the University of St Andrews, and the EPSRC Centre for Doctoral Training in Critical Resource Catalysis (CRITICAT) [Ph.D. studentship to SS: EP/L016419/1]. D. M. and P.P thank the Italian Ministry of University Research (MIUR) for funding [RBSI14PBC6].The structures and physicochemical properties of surface-stabilizing molecules play a critical role in defining the properties, interactions, and functionality of hybrid nanomaterials such as monolayer-stabilized nanoparticles. Concurrently, the distinct surface-bound interfacial environment imposes very specific conditions on molecular reactivity and behavior in this setting. Our ability to probe hybrid nanoscale systems experimentally remains limited, yet understanding the consequences of surface confinement on molecular reactivity is crucial for enabling predictive nanoparticle synthon approaches for postsynthesis engineering of nanoparticle surface chemistry and construction of devices and materials from nanoparticle components. Here, we have undertaken an integrated experimental and computational study of the reaction kinetics for nanoparticle-bound hydrazones, which provide a prototypical platform for understanding chemical reactivity in a nanoconfined setting. Systematic variation of just one molecular-scale structural parameter—the distance between reactive site and nanoparticle surface—showed that the surface-bound reactivity is influenced by multiscale effects. Nanoparticle-bound reactions were tracked in situ using 19F NMR spectroscopy, allowing direct comparison to the reactions of analogous substrates in bulk solution. The surface-confined reactions proceed more slowly than their solution-phase counterparts, and kinetic inhibition becomes more significant for reactive sites positioned closer to the nanoparticle surface. Molecular dynamics simulations allowed us to identify distinct supramolecular architectures and unexpected dynamic features of the surface-bound molecules that underpin the experimentally observed trends in reactivity. This study allows us to draw general conclusions regarding interlinked structural and dynamical features across several length scales that influence interfacial reactivity in monolayer-confined environments.PostprintPeer reviewe

Development of Agricultural Market and Trade Policies in the CEE Candidate Countries.

This synthesis report focuses on the evolution of agricultural market and trade policies in the Central and Eastern European (CEE) candidate countries in the period 1997 to 2001. The developments were crucially influenced by (OECD, 2000a): ⢠the situation in world agricultural markets; ⢠the overall macroeconomic development in the countries considered; ⢠the prospective EU accession; ⢠bringing domestic agricultural policy in line with the Uruguay Agreement on Agriculture (URAA). High 1997 agricultural prices on world commodity markets were followed by a marked depression in 1998. With the exemption of milk products this trend continued in 1999. Likewise the economic and financial crisis in Russia had a considerable impact on agricultural policies. It hit the regions´ exports resulting in a decline in industrial as well as agricultural output1. Thus, compared to the previous years most of the CEE candidate countries experienced a slow down or even negative rates of growth in their Gross Domestic Product (GDP) in 1998 and 1999. In addition those countries felt increased budgetary pressures. Agricultural market and trade policies largely reacted to these developments. Border protection was increased in many countries in 1998. This was combined in some cases with export subsidies, and ad hoc producer aids to mitigate the adverse effects. The prospect of EU accession also had an influence on the agricultural policy design in the region with many countries implementing EU-type policy instruments. Thus, the importance of per hectare and per head payments increased in the region, quota like measures were implemented in some countries and as part of this development Estonia introduced tariffs for agro-food imports. Finally, many countries also continued to adjust their policies to comply with their commitments agreed to in the World Trade Organisation (WTO). Despite these general tendencies there are also differences in the development of agricultural policies between the various CEE candidates. Chapter 2 therefore provides an overview of the changes of agricultural market and trade policies in each of the 10 accession countries. It addresses the policy issues market access (e.g. tariffs, special safeguard measures), export subsidies (value and quantities) and domestic support (intervention policies, direct payments, input subsidies, production quotas). Chapter 3 provides a brief assessment of recent policy developments in the region in the light of EU accession and WTO commitments. The development of prices and values, e.g. export subsidies, agricultural support expenditure, were presented in the background papers provided by the country experts in current prices in national currencies. In this synthesis report they are in addition converted in Euro. This firstly allows for a better comparison among the CEE candidate countries as well as between those countries and the EU. Some of the accession countries still suffer from high inflation and thus a strong depreciation of their currency. Thus secondly, the conversion to Euros allows the comparisons to be made in real terms.Industrial Organization, International Development, Productivity Analysis,

A Compilation of Global Bio-Optical In Situ Data for Ocean-Colour Satellite Applications

A compiled set of in situ data is important to evaluate the quality of ocean-colour satellite-data records. Here we describe the data compiled for the validation of the ocean-colour products from the ESA Ocean Colour Climate Change Initiative (OC-CCI). The data were acquired from several sources (MOBY, BOUSSOLE, AERONET-OC, SeaBASS, NOMAD, MERMAID, AMT, ICES, HOT, GeP&CO), span between 1997 and 2012, and have a global distribution. Observations of the following variables were compiled: spectral remote-sensing reflectances, concentrations of chlorophyll a, spectral inherent optical properties and spectral diffuse attenuation coefficients. The data were from multi-project archives acquired via the open internet services or from individual projects, acquired directly from data providers. Methodologies were implemented for homogenisation, quality control and merging of all data. No changes were made to the original data, other than averaging of observations that were close in time and space, elimination of some points after quality control and conversion to a standard format. The final result is a merged table designed for validation of satellite-derived ocean-colour products and available in text format. Metadata of each in situ measurement (original source, cruise or experiment, principal investigator) were preserved throughout the work and made available in the final table. Using all the data in a validation exercise increases the number of matchups and enhances the representativeness of different marine regimes. By making available the metadata, it is also possible to analyse each set of data separately. The compiled data are available at doi:10.1594/PANGAEA.854832 (Valente et al., 2015)

A compilation of global bio-optical in situ data for ocean-colour satellite applications - version three

A global in situ data set for validation of ocean colour products from the ESA Ocean Colour Climate Change Initiative (OC-CCI) is presented. This version of the compilation, starting in 1997, now extends to 2021, which is important for the validation of the most recent satellite optical sensors such as Sentinel 3B OLCI and NOAA-20 VIIRS. The data set comprises in situ observations of the following variables: spectral remote-sensing reflectance, concentration of chlorophyll-a, spectral inherent optical properties, spectral diffuse attenuation coefficient, and total suspended matter. Data were obtained from multi-project archives acquired via open internet services or from individual projects acquired directly from data providers. Methodologies were implemented for homogenization, quality control, and merging of all data. Minimal changes were made on the original data, other than conversion to a standard format, elimination of some points, after quality control and averaging of observations that were close in time and space. The result is a merged table available in text format. Overall, the size of the data set grew with 148 432 rows, with each row representing a unique station in space and time (cf. 136 250 rows in previous version; Valente et al., 2019). Observations of remote-sensing reflectance increased to 68 641 (cf. 59 781 in previous version; Valente et al., 2019). There was also a near tenfold increase in chlorophyll data since 2016. Metadata of each in situ measurement (original source, cruise or experiment, principal investigator) are included in the final table. By making the metadata available, provenance is better documented and it is also possible to analyse each set of data separately. The compiled data are available at https://doi.org/10.1594/PANGAEA.941318 (Valente et al., 2022)

Quantitative Structure–Property Relationship Studies on Ostwald Solubility and Partition Coefficients of Organic Solutes in Ionic Liquids

Article discussing quantitative structure-property relationship studies on Ostwald solubility and partition coefficients of organic solutes in ionic liquids