Le développement de nouvelles technologies permettant d’obtenir des procédés de fabrication novateurs, de même que l’utilisation de nouveaux matériaux et lubrifiants, ont rendu possible une amélioration globale de l’efficacité des systèmes mécaniques et la résolution de nombreuses défaillances. Néanmoins, certains types de détérioration comme le grippage restent difficiles à appréhender car ils résultent de nombreux paramètres connexes tels que le régime de lubrification, la température du contact et le coefficient de frottement. Le grippage est un phénomène qui apparait de manière brutale et qui se caractérise par des arrachements et des transferts de matières entre les surfaces en contact pouvant aller jusqu’à la destruction complète du système. Ce dernier est généralement associé à une mauvaise dissipation des calories entrainant des températures de contact élevées. De nombreux critères basés sur la dissipation d’énergie dans le contact ont été établis sans pour autant que l’un d’eux ne soit unanimement reconnu par la communauté scientifique. La première partie de cette étude a consisté à caractériser le comportement en frottement d’un couple matériau-lubrifiant grâce à l’utilisation d’une machine bi-disque. En parallèle, une modélisation thermique de ce banc d’essais a été réalisée en utilisant la méthode des réseaux thermiques. Les corrélations entre les formules analytiques et les mesures expérimentales ont permis d’aboutir à l’établissement d’une loi de frottement liant conditions de contact et température de masse des éprouvettes. Il a aussi pu être démontré que la température de masse des disques pouvait être considérablement différente de la température d’injection du lubrifiant en fonction des conditions opératoires. Ce résultat permet une analyse nouvelle des critères de grippage dont la plupart assimilent la température des éprouvettes à celle d’injection du lubrifiant. Malgré cela, les différents essais de grippage réalisés montrent que l’unique considération de la température de contact pour établir un critère de grippage s’avère insuffisante. / The development of new technologies, which allow innovative manufacturing processes, as well as the use of new materials and lubricants have led to an overall improvement of mechanical systems efficiency and reliability. However some failures, like scuffing, remain difficult to understand since they depend on many related parameters such as the lubrication regime, the contact temperature and the friction coefficient. Scuffing is a critical damage that appears suddenly and which is characterised by local welds and scratches between the sliding surfaces. It can lead to complete destruction of the mechanical system. This phenomenon is in general related to poor heat dissipation and overheating resulting in high contact temperature. Numerous studies were conducted in order to establish a scuffing criterion based on energetic approach. But none of them is unanimously recognized by the scientific community. The first part of this study consisted in characterizing the frictional behaviour of a given couple of lubricant and material thanks to the use of a twin-disc machine. In a second part, a thermal modelling of this test bench has been realised using the thermal network methodology. Correlations between analytical formulas and experimental measurements allowed to establish a friction law relating contact conditions and disc bulk temperature. It has also been demonstrated that the disc bulk temperature could be considerably different from the lubricant injection temperature depending on the operating conditions. This result allows a new interpretation of existing scuffing criteria, which for most of them consider the disc temperature to equal the oil temperature. Despite this analysis, the scuffing experiments performed reveal that accounting solely for the contact temperature is not sufficient to establish a reliable scuffing criterion.

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由於政經環境之變遷、公司治理的缺漏和外部監理機制之失調，常導致重大金融犯罪之發生，與其惡害卻由全民負擔之不公現象。於是除嚴刑峻罰外，奠基於任何人均不得從犯罪中獲利之犯罪所得剝奪理念與制度設計，遂於二ＯＯ四年金融七法修法時被廣泛納入。惟歷經一段期間之適用後，其法實效性如何？有無源於其他刑事法制無從配合，或囿於司法實務判解之困頓，所導致的扞格？部分國際公約與其他國家之相關法制設計及運作理念，有無值得比較、參研之處，均殊值探研。 　　本文嘗試先掌握金融犯罪之特性，與近來金融犯罪防制法規之演變。其次，再就我國犯罪所得剝奪法制沿革、犯罪所得之界定、計算為研析，並探索犯罪所得剝奪法制在預防、打擊與抗制金融犯罪等之必要性，以及其應通過之憲法基權保障檢驗。再者，則希能透過偵審案例，探究研現階段我國金融犯罪防制法規，在犯罪所得之暫時保全與終局剝奪上所面臨之實務困境及問題；並瞭解部分重要之國際公約與美、英、日等國家有關法制之設計。最後，則期能歸結相關問題與爭議，並融合法制建構、實務運作、外國法制借鏡等數個層面，提出可能之解決途徑或修法建議。 / Political and economic changes, incomplete of corporate governance, and imbalance of external supervision mechanism are all reasons for occurrence of major financial fraud. The losses and costs of major financial fraud, in general, are always enormous. Unfortunately, most people, instead of offenders, need to bear the huge losses. As a result, except the strategy of severe punishment, the idea and regulations on deprivation proceeds of crime were introduced to combat these problems in 2004. However, after a period of practicing, how about the application and practice of regulations on deprivation proceeds of crime is. Therefore, we are concerned about: are there any problems or difficulties resulting from criminal legal system and the practice of precedent itself? What we can learn from international conventions and other countries’ similar legal system? The thesis, first of all, attempts to figure out the feature of major financial fraud and the changes of financial regulations. Secondly, we try to explore the history of regulations on deprivation proceeds of crime, the definition and the calculation of proceeds of crime, and whether the regulations on deprivation proceeds of crime are essential for preventing and against major financial fraud or not. Meanwhile, in order to guarantee and protect the fundamental rights of people, we also hope to exam the regulations on deprivation proceeds of crime by the concepts of constitution. In additions, according to the case study, the thesis also longs for exploring what are the practical problems and dilemmas for current regulations on temporary seizure and final forfeiture procedures. At the same time, comparing with the international conventions and other countries’ similar legal system on laundering, search, freeze, seizure and confiscation of the proceeds from crime is also important and useful for this study. Finally, after concluding the relative problems and debates about this topic, of course, the paper hopes to propose a possible approach or legal amendment by integrating legal system modification, legal practice, and foreign legal system.

Recent literature has shown that AMPA (α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid) receptors lacking the GluR2 subunit (thus calcium permeable) are widely expressed in the CNS, especially in interneurons and glia, where they contribute to synaptic transmission and plasticity. Studies have also indicated that calcium permeable AMPARs (CP-AMPARs) are expressed and participate in synaptic regulation in principal neurons, including hippocampal pyramidal neurons. Furthermore, CP-AMPARs and their resultant calcium influx are implicated in various pathophysiological conditions such as ischemia and seizures. However, the synaptic events activated by calcium influx through CP-AMPARs remain unknown. I took advantage of genetically altered mice without (GluR2-/-) or with reduced GluR2 (GluR2+/-), thus allowing the expression and detailed analysis of synaptic CP-AMPARs in hippocampal pyramidal neurons. Utilizing electrophysiological techniques, I demonstrated that these receptors were capable of inducing numerous forms of long-term potentiation (referred to as CP-AMPAR-dependent LTP) through a number of different induction protocols, including high-frequency stimulation (HFS) and theta-burst stimulation (TBS). This included a previously undemonstrated form of protein-synthesis dependent late-LTP (L-LTP) at CA1 synapses that is NMDA-receptor (NMDAR) independent. This form of plasticity was completely blocked by the selective CP-AMPAR inhibitor IEM-1460. Surprisingly, calcium/calmodulin-dependent kinase II (CaMKII), the key protein kinase that is indispensable for NMDAR-dependent LTP at CA1 synapses appeared to be not required for the induction of CP-AMPAR-dependent LTP due to the lack of effect of two separate pharmacological inhibitors (KN-62 and staurosporine) on this form of potentiation. Both KN-62 and staurosporine strongly inhibited NMDAR dependent LTP in control studies. In contrast, inhibitors for the extracellular signal-regulated kinase/mitogen-activated protein kinase (ERK/MAPK) cascade (PD98059 and U0126) significantly attenuated this CP-AMPAR-dependent LTP. Additional studies with knockout mice revealed that the ERK/MAPK signalling cascade is likely acting through p-21 activated kinase 1 (or PAK1, a Rho-GTPase associated kinase) dependent mechanisms. These results suggest that distinct synaptic signalling underlies GluR2-lacking CP-AMPAR-dependent LTP, and reinforces the recent notions that CP-AMPARs are important facilitators of synaptic plasticity in the brain.

Recent literature has shown that AMPA (α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid) receptors lacking the GluR2 subunit (thus calcium permeable) are widely expressed in the CNS, especially in interneurons and glia, where they contribute to synaptic transmission and plasticity. Studies have also indicated that calcium permeable AMPARs (CP-AMPARs) are expressed and participate in synaptic regulation in principal neurons, including hippocampal pyramidal neurons. Furthermore, CP-AMPARs and their resultant calcium influx are implicated in various pathophysiological conditions such as ischemia and seizures. However, the synaptic events activated by calcium influx through CP-AMPARs remain unknown. I took advantage of genetically altered mice without (GluR2-/-) or with reduced GluR2 (GluR2+/-), thus allowing the expression and detailed analysis of synaptic CP-AMPARs in hippocampal pyramidal neurons. Utilizing electrophysiological techniques, I demonstrated that these receptors were capable of inducing numerous forms of long-term potentiation (referred to as CP-AMPAR-dependent LTP) through a number of different induction protocols, including high-frequency stimulation (HFS) and theta-burst stimulation (TBS). This included a previously undemonstrated form of protein-synthesis dependent late-LTP (L-LTP) at CA1 synapses that is NMDA-receptor (NMDAR) independent. This form of plasticity was completely blocked by the selective CP-AMPAR inhibitor IEM-1460. Surprisingly, calcium/calmodulin-dependent kinase II (CaMKII), the key protein kinase that is indispensable for NMDAR-dependent LTP at CA1 synapses appeared to be not required for the induction of CP-AMPAR-dependent LTP due to the lack of effect of two separate pharmacological inhibitors (KN-62 and staurosporine) on this form of potentiation. Both KN-62 and staurosporine strongly inhibited NMDAR dependent LTP in control studies. In contrast, inhibitors for the extracellular signal-regulated kinase/mitogen-activated protein kinase (ERK/MAPK) cascade (PD98059 and U0126) significantly attenuated this CP-AMPAR-dependent LTP. Additional studies with knockout mice revealed that the ERK/MAPK signalling cascade is likely acting through p-21 activated kinase 1 (or PAK1, a Rho-GTPase associated kinase) dependent mechanisms. These results suggest that distinct synaptic signalling underlies GluR2-lacking CP-AMPAR-dependent LTP, and reinforces the recent notions that CP-AMPARs are important facilitators of synaptic plasticity in the brain.

Dysfunction in the central nervous system of the neonate is often first identified through seizures. The diffculty in detecting clinical seizures, which involves the observation of physical manifestations characteristic to newborn seizure, has placed greater emphasis on the detection of newborn electroencephalographic (EEG) seizure. The high incidence of newborn seizure has resulted in considerable mortality and morbidity rates in the neonate. Accurate and rapid diagnosis of neonatal seizure is essential for proper treatment and therapy. This has impelled researchers to investigate possible methods for the automatic detection of newborn EEG seizure. This thesis is focused on the development of algorithms for the automatic detection of newborn EEG seizure using adaptive time-frequency signal processing. The assessment of newborn EEG seizure detection algorithms requires large datasets of nonseizure and seizure EEG which are not always readily available and often hard to acquire. This has led to the proposition of realistic models of newborn EEG which can be used to create large datasets for the evaluation and comparison of newborn EEG seizure detection algorithms. In this thesis, we develop two simulation methods which produce synthetic newborn EEG background and seizure. The simulation methods use nonlinear and time-frequency signal processing techniques to allow for the demonstrated nonlinear and nonstationary characteristics of the newborn EEG. Atomic decomposition techniques incorporating redundant time-frequency dictionaries are exciting new signal processing methods which deliver adaptive signal representations or approximations. In this thesis we have investigated two prominent atomic decomposition techniques, matching pursuit and basis pursuit, for their possible use in an automatic seizure detection algorithm. In our investigation, it was shown that matching pursuit generally provided the sparsest (i.e. most compact) approximation for various real and synthetic signals over a wide range of signal approximation levels. For this reason, we chose MP as our preferred atomic decomposition technique for this thesis. A new measure, referred to as structural complexity, which quantifes the level or degree of correlation between signal structures and the decomposition dictionary was proposed. Using the change in structural complexity, a generic method of detecting changes in signal structure was proposed. This detection methodology was then applied to the newborn EEG for the detection of state transition (i.e. nonseizure to seizure state) in the EEG signal. To optimize the seizure detection process, we developed a time-frequency dictionary that is coherent with the newborn EEG seizure state based on the time-frequency analysis of the newborn EEG seizure. It was shown that using the new coherent time-frequency dictionary and the change in structural complexity, we can detect the transition from nonseizure to seizure states in synthetic and real newborn EEG. Repetitive spiking in the EEG is a classic feature of newborn EEG seizure. Therefore, the automatic detection of spikes can be fundamental in the detection of newborn EEG seizure. The capacity of two adaptive time-frequency signal processing techniques to detect spikes was investigated. It was shown that a relationship between the EEG epoch length and the number of repetitive spikes governs the ability of both matching pursuit and adaptive spectrogram in detecting repetitive spikes. However, it was demonstrated that the law was less restrictive forth eadaptive spectrogram and it was shown to outperform matching pursuit in detecting repetitive spikes. The method of adapting the window length associated with the adaptive spectrogram used in this thesis was the maximum correlation criterion. It was observed that for the time instants where signal spikes occurred, the optimal window lengths selected by the maximum correlation criterion were small. Therefore, spike detection directly from the adaptive window optimization method was demonstrated and also shown to outperform matching pursuit. An automatic newborn EEG seizure detection algorithm was proposed based on the detection of repetitive spikes using the adaptive window optimization method. The algorithm shows excellent performance with real EEG data. A comparison of the proposed algorithm with four well documented newborn EEG seizure detection algorithms is provided. The results of the comparison show that the proposed algorithm has significantly better performance than the existing algorithms (i.e. Our proposed algorithm achieved a good detection rate (GDR) of 94% and false detection rate (FDR) of 2.3% compared with the leading algorithm which only produced a GDR of 62% and FDR of 16%). In summary, the novel contribution of this thesis to the fields of time-frequency signal processing and biomedical engineering is the successful development and application of sophisticated algorithms based on adaptive time-frequency signal processing techniques to the solution of automatic newborn EEG seizure detection.

Les crises épileptiques sont des épisodes paroxysmiques d'activité cérébrale hypersynchrone. Ce travail de thèse s'attache à examiner les mécanismes de propagation des crises d'épilepsie sur une échelle temporelle lente et une grande échelle spatiale dans le cerveau humain et à les appliquer au contexte clinique. Chez les patients souffrant d'épilepsie partielle réfractaire, les crises débutent dans certaines régions localisées du cerveau, dénommées zone épileptogène, avant de recruter des régions distantes. Le succès de l'ablation chirurgicale de la zone epileptogène dépend principalement de sa délimitation adéquate, un problème souvent épineux en pratique clinique. À cela s'ajoute notre compréhension parcellaire des mécanismes à l'origine des crises et de leur propagation. Nous utilisons un modèle mathématique de masse neuronale reproduisant le décours temporel de l'activité moyenne critique et intercritique d'une région cérébrale, guidé de manière autonome par une variable permittive lente. Nous introduisons tout d'abord un couplage permittif lent entre ces masses neuronales, afin de révéler l'importance de la variété lente dans le recrutement des régions cérébrales dans la crise. Nous présentons ensuite un pipeline de traitement des données structurelles et de diffusion IRM pour reconstruire automatiquement le cerveau virtuel d'un patient. Nous utilisons ensuite une analyse de stabilité linéaire et la connectivité large-échelle pour prédire la zone de propagation. Nous appliquons notre méthode à un jeu de données de 15 patients épileptiques et démontrons l'importance du connectome pour prédire la direction de propagation des crises. / Epileptic seizures are paroxysmal hypersynchronizations of brain activity, spanning several temporal and spatial scales. In the present thesis, we investigate the mechanisms of epileptic seizure propagation on a slow temporal and large spatial scale in the human brain and apply them to a clinical context. For patients with partial refractory epilepsy, seizures arise from a localized region of the brain, the so-called epileptogenic zone, before recruiting distant regions. Success of the resective surgery of the epileptogenic zone depends on its correct delineation, which is often difficult in clinical practice. Furthermore, the mechanisms of seizure onset and recruitment are still largely unknown. We use a mathematical neural mass model to reproduce the time course of interictal and ictal mean activity of a brain region, in which the switching between these states is guided by an autonomous slow permittivity variable. We first introduce a slow permittivity coupling function between these neural masses, hypothesizing the importance of the slow manifold in the recruitment of brain regions into the seizure. Before exploring large-scale networks of such coupled systems, we present a processing pipeline for automatic reconstruction of a patient's virtual brain, including surface and connectivity (i.e., connectome), using structural and diffusion MRI, and tractography methods. Using linear stability analysis and large-scale connectivity, we predict the propagation zone. We apply our method to a dataset of 15 epileptic patients and establish the importance of the connectome in determining large-scale propagation of epileptic seizures.

The problem encountered by the researcher was that the South African Police Service Cyber-Crimes Unit is experiencing problems in seizing computer evidence. The following problems were identified by the researcher in practice: evidence is destroyed or lost because of mishandling by investigators; computer evidence is often not obtained or recognised, due to a lack of knowledge and skills on the part of investigators to properly seize computer evidence; difficulties to establish authenticity and initiate a chain of custody for the seized evidence; current training that is offered is unable to cover critical steps in the performance of seizing computer evidence; computer seizure as a technique requires specialised knowledge and continuous training, because the information technology industry is an ever-changing area. An empirical research design, followed by a qualitative research approach, allowed the researcher to also obtain information from practice. A thorough literature study, complemented by interviews, was done to collect the required data for the research. Members of the South African Police Cyber-crime Unit and prosecutors dealing with cyber-crime cases were interviewed to obtain their input into, and experiences on, the topic. The aim of the study was to explore the role of computers in the forensic investigation process, and to determine how computers can be seized without compromising evidence. The study therefore also aimed at creating an understanding and awareness about the slippery nature of computer evidence, and how it can find its way to the court of law without being compromised. The research has revealed that computer crime is different from common law or traditional crimes. It is complicated, and therefore only skilled and qualified forensic experts should be used to seize computer evidence, to ensure that the evidence is not compromised. Training of cyber-crime technicians has to be priority, in order to be successful in seizing computers. / Department of Criminology / M.Tech. (Forensic Investigation)

Text in Afrikaans / "Free people expect much from their police. In such societies the police stand at the point of balance on the one hand securing human rights on the other exercising their lawful powers given to them by Governments in the name of the people, to protect people and their institutions" (J Alderson Human Rights and Police Rights. Publication of the Council of Europe.) This is no small expectation. It means that the police are expected to maintain and secure the principles of democracy and human rights, the principles upon which our Constitution is based. At the same time it is the duty of a police service to maintain law and order which sometimes require the exercise of power and the use of force which on the face of it may appear to violate human dignity and certain rights and freedoms which a police force is expected to maintain in a democratic society. The manner of exercising that power has an impact on the credibility and effectiveness of the police. Human rights law internationally accepts that a police service needs to be given the power to, at times restrict certain individual freedoms in the interests of the security of the community at large. These restrictions may take place only in a constitutional way. If it takes place in an unconstitutional way the courts must have the right to exclude evidence which is unconstitutionally obtained. At this stage the courts have to formulate such a qualified exclusionary rule, but the ultimate goal must be to include such an exclusionary rule in a future Constitution. / Department of Criminal and Procedural Law / LL.M.

Ce travail porte sur l'étude des effets thermiques dans un palier hydrodynamique, alimentée par une rainure circonférentielle (CGJB) sous charge statique, en tenant compte des phénomènes de rupture de film dans la zone divergente. La recherche expérimentale a été réalisée à l'Université de Poitiers ; elle a permis une détermination minutieuse des champs de pression et de température sur la portée située à l’avant d’un CGJB et dans la section médiane de sa rainure. Ces mesures sous un régime stationnaire sont originales par rapport celles existantes, quel que le type de palier, de par le grand nombre de points de mesure, 180 pour la pression et 144 pour la température, l'instrumentation de haute précision, la large plage de conditions d'exploitation (pression spécifique variant de 0,125 à 2 MPa et vitesse linéaire de l’arbre allant de 5,25 à 21 m/s). Des études du régime transitoire de démarrage au régime stationnaire établi ont été effectuées pour de faibles charges. Des expériences effectuées à l'Université "Politehnica" de Bucarest ont montré une bonne corrélation entre la perte de portance, anti-portance et la rupture du film sur un patin Rayleigh (RSP), ce qui est essentiel pour l'évaluation des phénomènes de rupture dans les paliers. Quelques modèles théoriques ont été utilisés pour évaluer les risques de serrage au démarrage qui est une instabilité thermoélastique catastrophique. Les principaux résultats sont l’obtention d’une base fiable de données expérimentales permettant le développement des modèles théoriques avancés et l’infirmation d’une répartition de pression constante dans la zone divergente et de pression et température constantes dans la rainure d'alime / The main objective of the thesis is to study the thermal effects in steadily loaded circumferential groove journal bearings (CGJBs), including cavitation phenomena occurring in the divergent zone of such bearings. Experimental research conducted at University of Poitiers – Institut Pprime – France enabled a thorough determination of film pressure and temperature fields for the front land of a CGJB plus its mid-groove section, and several performance parameters. Measurements of film pressure and temperature fields under steady-state regime surpassed existing works, regardless of journal bearing design, through: sheer number of land measurement locations, 180 for pressure and for 144 temperature; high precision state of art instrumentation; broad range of operating conditions, 0.125 … 2 MPa specific bearing pressure and 5.25 … 21 m/s shaft speeds. Transient start-up to steady-statestabilization regimes have been investigated at low loads. Experiments at University "Politehnica" of Bucharest – Romania showed a correlation between the downforce thrust and film rupture for a Rayleigh step pin (RSP), important in evaluating divergent zone cavitation phenomena. Theoretical research consisted in developing simple models for evaluating CGJBs performance in steady-state and transient start-up regimes. Several theoretical models were employed for assessing start-up seizure, catastrophic transient thermoelastic instability and damage risk. The major result is a reliable experimental data collection that: enables development of advanced theoretical models; disprove flat film pressure distributions in divergent zones, and constant pressure and temperature in the bearing supply groov