Generative Adversarial Networks for Mitigating Biases in Machine Learning Systems

In this paper, we propose a new framework for mitigating biases in machine learning systems. The problem of the existing mitigation approaches is that they are model-oriented in the sense that they focus on tuning the training algorithms to produce fair results, while overlooking the fact that the training data can itself be the main reason for biased outcomes. Technically speaking, two essential limitations can be found in such model-based approaches: 1) the mitigation cannot be achieved without degrading the accuracy of the machine learning models, and 2) when the data used for training are largely biased, the training time automatically increases so as to find suitable learning parameters that help produce fair results. To address these shortcomings, we propose in this work a new framework that can largely mitigate the biases and discriminations in machine learning systems while at the same time enhancing the prediction accuracy of these systems. The proposed framework is based on conditional Generative Adversarial Networks (cGANs), which are used to generate new synthetic fair data with selective properties from the original data. We also propose a framework for analyzing data biases, which is important for understanding the amount and type of data that need to be synthetically sampled and labeled for each population group. Experimental results show that the proposed solution can efficiently mitigate different types of biases, while at the same time enhancing the prediction accuracy of the underlying machine learning model

Design of controlled RF switch for beam steering antenna array

YesA printed dipole antenna integrated with a duplex RF switch used for mobile base station antenna beam steering is presented. A coplanar waveguide to coplanar strip transition was adopted to feed the printed dipole. A novel RF switch circuit, used to control the RF signal fed to the dipole antenna and placed directly before the dipole, was proposed. Simulated and measured data for the CWP-to-CPS balun as well as the measured performance of the RF switch are shown. It has demonstrated the switch capability to control the beam in the design of beam steering antenna array for mobile base station applications

Theoretical and Applied Foundations for Intrusion Detection in Single and Federated Clouds

Les systèmes infonuagiques deviennent de plus en plus complexes, plus dynamiques et hétérogènes. Un tel environnement produit souvent des données complexes et bruitées, empêchant les systèmes de détection d’intrusion (IDS) de détecter des variantes d’attaques connues. Une seule intrusion ou une attaque dans un tel système hétérogène peut se présenter sous des formes différentes, logiquement mais non synthétiquement similaires. Les IDS traditionnels sont incapables d’identifier ces attaques, car ils sont conçus pour des infrastructures spécifiques et limitées. Par conséquent, une détection précise dans le nuage ne sera absolument pas identifiée. Outre le problème de l’infonuagique, les cyber-attaques sont de plus en plus sophistiquées et difficiles à détecter. Il est donc extrêmement compliqué pour un unique IDS d’un nuage de détecter toutes les attaques, en raison de leurs implications, et leurs connaissances limitées et insuffisantes de celles-ci. Les solutions IDS actuelles de l’infonuagique résident dans le fait qu’elles ne tiennent pas compte des aspects dynamiques et hétérogènes de l’infonuagique. En outre, elles s’appuient fondamentalement sur les connaissances et l’expérience locales pour identifier les attaques et les modèles existants. Cela rend le nuage vulnérable aux attaques «Zero-Day». À cette fin, nous résolvons dans cette thèse deux défis associés à l’IDS de l’infonuagique : la détection des cyberattaques dans des environnements complexes, dynamiques et hétérogènes, et la détection des cyberattaques ayant des informations limitées et/ou incomplètes sur les intrusions et leurs conséquences. Dans cette thèse, nous sommes intéressés aux IDS génériques de l’infonuagique afin d’identifier les intrusions qui sont indépendantes de l’infrastructure utilisée. Par conséquent, à chaque fois qu’un pressentiment d’attaque est identifié, le système de détection d’intrusion doit être capable de reconnaître toutes les variantes d’une telle attaque, quelle que soit l’infrastructure utilisée. De plus, les IDS de l’infonuagique coopèrent et échangent des informations afin de faire bénéficier chacun des expertises des autres, pour identifier des modèles d’attaques inconnues.----------ABSTRACT: Cloud Computing systems are becoming more and more complex, dynamic and heterogeneous. Such an environment frequently produces complex and noisy data that make Intrusion Detection Systems (IDSs) unable to detect unknown variants of known attacks. A single intrusion or an attack in such a heterogeneous system could take various forms that are logically but not synthetically similar. This, in turn, makes traditional IDSs unable to identify these attacks, since they are designed for specific and limited infrastructures. Therefore, the accuracy of the detection in the cloud will be very negatively affected. In addition to the problem of the cloud computing environment, cyber attacks are getting more sophisticated and harder to detect. Thus, it is becoming increasingly difficult for a single cloud-based IDS to detect all attacks, because of limited and incomplete knowledge about attacks and implications. The problem of the existing cloud-based IDS solutions is that they overlook the dynamic and changing nature of the cloud. Moreover, they are fundamentally based on the local knowledge and experience to perform the classification of attacks and normal patterns. This renders the cloud vulnerable to “Zero-Day” attacks. To this end, we address throughout this thesis two challenges associated with the cloud-based IDS which are: the detection of cyber attacks under complex, dynamic and heterogeneous environments; and the detection of cyber attacks under limited and/or incomplete information about intrusions and implications. We are interested in this thesis in allowing cloud-based IDSs to be generic, in order to identify intrusions regardless of the infrastructure used. Therefore, whenever an intrusion has been identified, an IDS should be able to recognize all the different structures of such an attack, regardless of the infrastructure that is being used. Moreover, we are interested in allowing cloud-based IDSs to cooperate and share knowledge with each other, in order to make them benefit from each other’s expertise to cover unknown attack patterns. The originality of this thesis lies within two aspects: 1) the design of a generic cloud-based IDS that allows the detection under changing and heterogeneous environments and 2) the design of a multi-cloud cooperative IDS that ensures trustworthiness, fairness and sustainability. By trustworthiness, we mean that the cloud-based IDS should be able to ensure that it will consult, cooperate and share knowledge with trusted parties (i.e., cloud-based IDSs). By fairness, we mean that the cloud-based IDS should be able to guarantee that mutual benefits will be achieved through minimising the chance of cooperating with selfish IDSs. This is useful to give IDSs the motivation to participate in the community

La dimension africaine dans la politique étrangère libyenne 1969-2002

The aim of this thesis is to study the Libyan foreign policy in Africa from 1969 to 2002. The foreign Libyan political decision had been influence by many political, ideological and international directions. The petroleum had allowed to Libyan politics to exercise an important role by using important amount of money coming from the petroleum revenue. The latter had brought financial and economic assistance, which bring Libyan assistance policy essential in many African countries.After the end of the cold war and the world domination by the American politics, Libya had been accuse in the Lockerbie affaires and had been sanction by the United Nations. The political sanctions and the economic embargo conduct Libya to change its foreign policy and abandon the struggle against the presence of Americans and Israelis in Africa, as well as to adopt a foreign policy in the trends of Occidental interestL’objectif de la thèse est d’étudier la politique libyenne étrangère en Afrique pendant la période (1969-2002). Les décisions de la politique étrangère libyenne ont été influencées par plusieurs orientations politiques, idéologiques et internationales. Le pétrole a permis la politique libyenne d’exercer un rôle important en utilisant s’importantes sommes d’argents provenant de ses revenus pétrolier. Ces dernières ont permis d’apporter des aides financières et économiques, ce qui a rendu la politique libyenne d’aide indispensable dans beaucoup de pays africains.Apres la fin de la guerre froide et la domination de la politique américaine au niveau mondial, la Libye a été accusée de l’affaire Lockerbie et a été sanctionnée par les nation-Unis. Les sanctions politiques et l’embargo économique ont conduits la Libye a changé sa politique étrangère et abandonner la lutte contre la présence américaine et israélienne en Afrique, ainsi qu’adopter une politique étrangère avec les intérêts occidentaux

A trust-based game theoretical model for cooperative intrusion detection in multi-cloud environments

Cloud systems are becoming more complex and vulnerable to attacks. Cyber attacks are also becoming more sophisticated and harder to detect. Therefore, it is increasingly difficult for a single cloud-based intrusion detection system (IDS) to detect all attacks, because of limited and incomplete knowledge about attacks. The recent researches in cyber-security have shown that a co-operation among IDSs can bring higher detection accuracy in such complex computer systems. Through collaboration, a cloud-based IDS can consult other IDSs about suspicious intrusions and increase the decision accuracy. The problem of existing cooperative IDS approaches is that they overlook having untrusted (malicious or not) IDSs that may negatively effect the decision about suspicious intrusions in the cloud. Moreover, they rely on a centralized architecture in which a central agent regulates the cooperation, which contradicts the distributed nature of the cloud. In this paper, we propose a framework that enables IDSs to distributively form trustworthy IDSs communities. We devise a novel decentralized algorithm, based on coalitional game theory, that allows a set of cloud-based IDSs to cooperatively set up their coalition in such a way to make their individual detection accuracy increase, even in the presence of untrusted IDSs

Beam Steering of Time Modulated Antenna Arrays Using Particle Swarm Optimization

yesIn this paper, a simple switching process is employed to steer the beam of a vertically polarised circular antenna array. This is a simple method, in which the difference resulting from the induced currents when the radiating/loaded element is connected/disconnected from the ground plane. A time modulated switching process is applied through particle swarm optimisation.Electronics and Telecommunication

Frequency Tuned Planar Inverted F Antenna with L Shaped Slit Design for Wide Frequency Range.

yesA frequency tuned antenna has been designed to meet the coverage requirements of the DCS, PCS, UMTS and WLAN bands. The antenna consists of a main patch, and a planar inverted L (PIL) slot. The radiator patch is fed, and shorted, using simple feed lines with broadband characteristics. The handset represents the finite ground plane, and a varactor diode is mounted across the middle of the slot for tuning purposes. Initial tuning was obtained by placing lumped capacitors, instead of the varactor, over the radiator. Good agreement is obtained between the predicted and measured input return loss, gain and radiation pattern over the tuned frequency range.MSCR

Wireless Electromagnetic Radiation Assessment Based on the Specific Absorption Rate (SAR): A Review Case Study

Employing Electromagnetic Fields (EMFs) in new wireless communication and sensing technologies has substantially increased the level of human exposure to EMF waves. This paper presents a useful insight into the interaction of electromagnetic fields with biological media that is defined by the heat generation due to induced currents and dielectric loss. The Specific Absorption Rate (SAR) defines the heating amount in a biological medium that is irradiated by an electromagnetic field value. The paper reviews the radio frequency hazards due to the SAR based on various safety standards and organisations, including a detailed investigation of previously published work in terms of modelling and measurements. It also summarizes the most common techniques utilised between 1978 and 2021, in terms of the operational frequency spectrum, bandwidth, and SAR values

Design and modelling of beam steering antenna array for mobile and wireless applications using optimisation algorithms. Simulation and measrement of switch and phase shifter for beam steering antenna array by applying reactive loading and time modulated switching techniques, optimised using genetic algorithms and particle swarm methods.

The objectives of this work were to investigate, design and implement beam steering antenna arrays for mobile and wireless applications using the genetic algorithm (GA) and particle swarm optimisation (PSO) techniques as optimisation design tools. Several antenna designs were implemented and tested: initially, a printed dipole antenna integrated with a duplex RF switch used for mobile base station antenna beam steering was investigated. A coplanar waveguide (CPW) to coplanar strip (CPS) transition was adopted to feed the printed dipole. A novel RF switch circuit, used to control the RF signal fed to the dipole antenna and placed directly before it, was proposed. The measured performance of the RF switch was tested and the results confirmed its viability. Then two hybrid coupled PIN diode phase shifters, using Branchline and Rat-Race ring coupler structures, were designed and tested. The generation of four distinct phase shifts was implemented and studied. The variations of the scattering parameters were found to be realistic, with an acceptable ±2 phase shift tolerance. Next, antenna beam steering was achieved by implementing RF switches with ON or OFF mode functions to excite the radiating elements of the antenna array. The switching control process was implemented using a genetic algorithm (GA) method, subject to scalar and binary genes. Anti-phase feeding of radiating elements was also investigated. A ring antenna array with reflectors was modelled and analysed. An antenna of this type for mobile base stations was designed and simulation results are presented. Following this, a novel concept for simple beam steering using a uniform antenna array operated at 2.4 GHz was designed using GA. The antenna is fed by a single RF input source and the steering elements are reactively tuned by varactor diodes in series with small inductors. The beam-control procedure was derived through the use of a genetic algorithm based on adjusting the required reactance values to obtain the optimum solution as indicated by the cost function. The GA was also initially used as an optimisation tool to derive the antenna design from its specification. Finally, reactive loading and time modulated switching techniques are applied to steer the beam of a circular uniformly spaced antenna array having a source element at its centre. Genetic algorithm (GA) and particle swarm optimisation (PSO) processes calculate the optimal values of reactances loading the parasitic elements, for which the gain can be optimised in a desired direction. For time modulated switching, GA and PSO also determine the optimal on and off times of the parasitic elements for which the difference in currents induced optimises the gain and steering of the beam in a desired direction. These methods were demonstrated by investigating a vertically polarised antenna configuration. A prototype antenna was constructed and experimental results compared with the simulations. Results showed that near optimal solutions for gain optimisation, sidelobe level reduction and beam steering are achievable by utilising these methods. In addition, a simple switching process is employed to steer the beam of a horizontally polarised circular antenna array. A time modulated switching process is applied through Genetic Algorithm optimisation. Several model examples illustrate the radiation beams and the switching time process of each element in the array

The African dimension in Libyan foreign policy 1969-2002

L’objectif de la thèse est d’étudier la politique libyenne étrangère en Afrique pendant la période (1969-2002). Les décisions de la politique étrangère libyenne ont été influencées par plusieurs orientations politiques, idéologiques et internationales. Le pétrole a permis la politique libyenne d’exercer un rôle important en utilisant s’importantes sommes d’argents provenant de ses revenus pétrolier. Ces dernières ont permis d’apporter des aides financières et économiques, ce qui a rendu la politique libyenne d’aide indispensable dans beaucoup de pays africains.Apres la fin de la guerre froide et la domination de la politique américaine au niveau mondial, la Libye a été accusée de l’affaire Lockerbie et a été sanctionnée par les nation-Unis. Les sanctions politiques et l’embargo économique ont conduits la Libye a changé sa politique étrangère et abandonner la lutte contre la présence américaine et israélienne en Afrique, ainsi qu’adopter une politique étrangère avec les intérêts occidentaux.The aim of this thesis is to study the Libyan foreign policy in Africa from 1969 to 2002. The foreign Libyan political decision had been influence by many political, ideological and international directions. The petroleum had allowed to Libyan politics to exercise an important role by using important amount of money coming from the petroleum revenue. The latter had brought financial and economic assistance, which bring Libyan assistance policy essential in many African countries.After the end of the cold war and the world domination by the American politics, Libya had been accuse in the Lockerbie affaires and had been sanction by the United Nations. The political sanctions and the economic embargo conduct Libya to change its foreign policy and abandon the struggle against the presence of Americans and Israelis in Africa, as well as to adopt a foreign policy in the trends of Occidental interes