International Telemetering Conference Proceedings / October 21, 2002 / Town & Country Hotel and Conference Center, San Diego, California / This paper presents a Flight Safety System (FSS) for multiple, reliable Unmanned Air Vehicles (UAV’s) capable of flying Over-the-Horizon (OTH) and outside test range airspace. Expanded uses beyond flight safety, such as UAV Air Traffic Control, are considered also. This system satisfies the operational requirement for a Hazard Control Communication Channel as well as providing a reverse communications channel to provide Safety Critical Information to the Range Safety Officer (RSO). Upon examining 60 communications candidates, IRIDIUM accessed through a Data Distribution Network (DDN), with ARINC being a potential service provider, is recommended.

Thesis (MSc)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: Recent studies have shown that considering proof test data in a Reliability Based Design Optimization (RBDO) environment can result in design improvement. Proof testing involves the physical testing of each and every component before it enters into service. Considering the proof test data as part of the RBDO process allows for improvement of the original design, such as weight savings, while preserving high reliability levels. Composite Over-Wrapped Pressure Vessels (COPV) is used as an example application of achieving weight savings while maintaining high reliability levels. COPVs are light structures used to store pressurized fluids in space shuttles, the international space station and other applications where they are maintained at high pressure for extended periods of time. Given that each and every COPV used in spacecraft is proof tested before entering service and any weight savings on a spacecraft results in significant cost savings, this thesis put forward an application of RBDO that accounts for proof test data in the design of a COPV. The method developed in this thesis shows that, while maintaining high levels of reliability, significant weight savings can be achieved by including proof test data in the design process. Also, the method enables a designer to have control over the magnitude of the proof test, making it possible to also design the proof test itself depending on the desired level of reliability for passing the proof test. The implementation of the method is discussed in detail. The evaluation of the reliability was based on the First Order Reliability Method (FORM) supported by Monte Carlo Simulation. Also, the method is implemented in a versatile way that allows the use of analytical as well as numerical (in the form of finite element) models. Results show that additional weight savings can be achieved by the inclusion of proof test data in the design process. / AFRIKAANSE OPSOMMING: Onlangse studies het getoon dat die gebruik van ontwerp spesifieke proeftoets data in betroubaarheids gebaseerde optimering (BGO) kan lei tot 'n verbeterde ontwerp. BGO behels vele aspekte in die ontwerpsgebied. Die toevoeging van proeftoets data in ontwerpsoptimering bring te weë; die toetsing van 'n ontwerp en onderdele voor gebruik, die aangepaste en verbeterde ontwerp en gewig-besparing met handhawing van hoë betroubaarsheidsvlakke. 'n Praktiese toepassing van die BGO tegniek behels die ontwerp van drukvatte met saamgestelde materiaal bewapening. Die drukvatontwerp is 'n ligte struktuur wat gebruik word in die berging van hoë druk vloeistowwe in bv. in ruimtetuie, in die internasionale ruimtestasie en in ander toepassings waar hoë druk oor 'n tydperk verlang word. Elke drukvat met saamgestelde materiaal bewapening wat in ruimtevaartstelsels gebruik word, word geproeftoets voor gebruik. In ruimte stelselontwerp lei massa besparing tot 'n toename in loonvrag. Die tesis beskryf 'n optimeringsmetode soos ontwikkel en gebaseer op 'n BGO tegniek. Die metode word toegepas in die ontwerp van drukvatte met saamgestelde materiaal bewapening. Die resultate toon dat die gebruik van proeftoets data in massa besparing optimering onderhewig soos aan hoë betroubaarheidsvlakke moontlik is. Verdermeer, die metode laat ook ontwerpers toe om die proeftoetsvlak aan te pas om sodoende by ander betroubaarheidsvlakke te toets. In die tesis word die ontwikkeling en gebruik van die optimeringsmetode uiteengelê. Die evaluering van betroubaarheidsvlakke is gebaseer op 'n eerste orde betroubaarheids-tegniek wat geverifieer word met talle Monte Carlo simulasie resultate. Die metode is ook so geskep dat beide analitiese sowel as eindige element modelle gebruik kan word. Ten slotte, word 'n toepassing getoon waar resultate wys dat die gebruik van die optimeringsmetode met die insluiting van proeftoets data wel massa besparing kan oplewer.

<p>When using Voice over IP (VoIP) in Wireless Mesh Networks the overhead induced by the IEEE 802.11 PHY and MAC layer accounts for more than 80% of the channel utilization time, while the actual payload only uses 20% of the time. As a consequence, the Voice over IP capacity is very low. To increase the channel utilization efficiency and the capacity several IP packets can be aggregated in one large packet and transmitted at once. This paper presents a new hop-by-hop IP packet aggregation scheme for Wireless Mesh Networks.</p><p>The size of the aggregation packets is a very important performance factor. Too small packets yield poor aggregation efficiency; too large packets are likely to get dropped when the channel quality is poor. Two novel distributed protocols for calculation of the optimum respectively maximum packet size are described. The first protocol assesses network load by counting the arrival rate of routing protocol probe messages and constantly measuring the signal-to-noise ratio of the channel. Thereby the optimum packet size of the current channel condition can be calculated. The second protocol, which is a simplified version of the first one, measures the signal-to-noise ratio and calculates the maximum packet size.</p><p>The latter method is implemented in the ns-2 network simulator. Performance measurements with no aggregation, a fixed maximum packet size and an adaptive maximum packet size are conducted in two different topologies. Simulation results show that packet aggregation can more than double the number of supported VoIP calls in a Wireless Mesh Network. Adaptively determining the maximum packet size is especially useful when the nodes have different distances or the channel quality is very poor. In that case, adaptive aggregation supports twice as many VoIP calls as fixed maximum packet size aggregation.</p>

<p>Control systems utilizing wireless sensor and actuator networks can be severely affectedby the properties of the communication links. Radio fading and interferencemay cause communication losses and outages in situations when the radio environmentis noisy and low transmission power is desirable. This thesis proposes amethod to compensate for such unpredictable losses of data in the feedback controlloop by introducing a predictive outage compensator (POC). The POC is a filter tobe implemented at the receiver sides of networked control systems where it generatesartificial samples when data are lost. If the receiver node does not receive thedata, the POC suggests a command based on the history of past data. It is shownhow to design, tune and implement a POC. Theoretical bounds and simulationresults show that a POC can improve the closed-loop control performance undercommunication losses considerably. We provide a deterministic and a stochasticmethod to synthesize POCs. Worst-case performance bounds are given that relatethe closed-loop performance with the complexity of the compensator. We also showthat it is possible to achieve good performance with a low-order implementationbased on Hankel norm approximation. Tradeoffs between achievable performance,communication loss length, and POC order are discussed. The results are illustratedon a simulated example of a multiple-tank process. The thesis is concludedby an experimental validation of wireless control of a physical lab process. Herethe controller and the physical system are separated geographically and interfacedthrough a wireless medium. For the remote control we use a hybrid model predictivecontroller. The results reflect the difficulties in wireless control as well as theyhighlight the flexibility and possibilities one obtains by using wireless instead of awired communication medium.</p> / VR, SSF, VINNOVA via Networked Embedded Control Systems, EU Sixt Framework Program via HYCON and SOCRADES

Les crossing-overs (CO) sont indispensables dans la création variétale pour permettre l'introgression de régions d'intérêt dans les variétés agronomiques d'espèces cultivées telles que le blé tendre (Triticum aesstivum L.). Afin d'évaluer l'impact des facteurs qui influencent leur formation, nous avons entrepris une caractérisation fine de leur distribution sur le plus grand chromosome ( chromosome 3B, 995Mb) du blé tendre en s'appuyant sur la carte physique récemment développée et le séquençage de quelques régions de plusieurs mégabases. La comparaison entre une carte génétique dense (102 marqueurs) et une carte physique de délétion montre que 77% des CO sont présents dans les régions distales couvrant seuleument 25% du chromosome. La comparaison de différentes cartes génétiques montre de plus que cette distribution est conservée entre populations avec cependant des différences de taux de CO locaux entre populations mais également entre méiose mâle et femelle. Cette distribution est influencée par une interférence positive forte à des distances inférieures à 10 cM. Cependant, les faibles fréquences de CO observées au sein des régions proximales restent inexpliquées. En effet, la faible augmentation du taux de CO observée au sein des régions proximales placées en position distale suggère que la position proximale de ces régions sur le chromosome ne semble pas responsable de leur faible fréquence de CO. De plus, nous avons montré que ces faibles fréquences ne seraient pas non plus dues à une divergence de séquence entre chromosomes homologues au sein des régions proximales, la fréquence de CO étant toujours aussi faible au sein de celles-ci entre deux chromosomes homozygotes. En revanche, l'analyse à l'échelle d'une région séquencée de 3.1 Mb indique que les fréquences de CO importantes sont fortement corrélées avec la présence de gènes. L'inhibition de la formation des CO au sein des régions proximales pourrait ainsi s'expliquer par la présence de gènes en quantité moins importante dans ces régions comparées aux régions distales.

Shakespeare criticism has been a rapidly evolving field of literary studies. Scholars such as Francis Barker and Peter Hulme, Meredith Anne Skura, Stanley Wells, Harold Bloom and Sidney Shanker have continuously developed new theories and dismissed previous theories. In this essay, I discuss the negative results of such attitudes and the problems of “over-reading”, in the critiques which are based on the following theories: the post-colonial, psychoanalytical, biographical and ideological. I elaborate on the relevant arguments and issues within literary critique mentioned by Michael Taylor in his book Shakespeare Criticism in the Twentieth Century. To create a common ground for the theories, I have used critical texts concerning William Shakespeare’s The Tempest. I find that while all forms of literary critique have flaws, the theories also contribute valuable insights for further readings. I maintain that combining several forms of literary critique when analysing a text will create a more complex and in-depth reading, impossible to achieve through a singular critical theory.

Consumer credit has become a common source of finance for households, inevitable for the majority of them. Developments of credit markets that emerged as a result of economic hardship in 2008-2009, leads to the high relevance of the scientific researches on the topic. Traditional consumer loans provided by banks or credit unions are supplemented by the new debt instruments. The most popular and well known ones are payday loans (small amount, short term and high cost loans), having the high credit price (in APR terms) and are easily accessible. Because of such rapid growth and popularity of payday loans among socially vulnerable borrowers, these transactions became the object of regulation. The regulator here faces a very complex task - to balance the interests of the payday loan transaction parties (borrower and lender) throughout the process of the transaction. In the Baltic States, including Lithuania, payday lending transactions and their regulation is a well underexplored field of scientific research. Analysis of the scientific literature has revealed that there is a general disagreement on whether payday loans benefit or harm borrowers? Usually studies does not provide complete answer on how to regulate payday lending transactions in order to ensure access to credit and balance the interests of creditors and debtors. No one has offered a model of payday lending transactions regulation yet. Moreover, there is no generally established view on the balance of borrowers’ and... [to full text] / Vartojimo kreditavimas yra įprastas namų ūkių poreikių finansavimo šaltinis, neišvengiamas daugeliui jų. Kreditavimo rinkos pokyčiai, atsiradę ekonomikos sunkmečio laikotarpiu 2008-2009 metais, lemia ypatingai didelį šios tematikos mokslinių tyrimų aktualumą. Tradicines bankų ar kredito unijų teikiamas vartojimo paskolas papildė nauji skolinimo instrumentai, tarp kurių populiarūs ir žinomi – mažieji vartojimo kreditai, pasižymintys aukšta palūkanų norma ir lengvu prieinamumu. Dėl mažųjų vartojimo kreditų populiarumo tarp socialiai pažeidžiamų asmenų ir augimo, šie sandoriai tapo reguliavimo objektu. Reguliuotojui čia kyla sudėtingas uždavinys subalansuoti reguliavimo objekto – mažojo vartojimo kreditavimo sandorio šalių (skolininko ir kreditoriaus) interesus šio sandorio proceso metu. Baltijos šalyse, įskaitant ir Lietuvoje, mažojo vartojimo kreditavimo sandoriai ir jų reguliavimas yra visiškai mokslininkų netyrinėtas reiškinys.Mokslinės literatūros analizė parodė, kad tyrėjai nesutaria ar visumoj mažieji vartojimo kreditai labiau padeda vartotojams, ar yra jiems labiau žalingi. Dažnai moksliniai tyrimai neatsako į klausimą - kaip reguliuoti mažojo vartojimo kreditavimo sandorius, kad būtų užtikrintas kredito prieinamumas ir subalansuota skolininko bei kreditorių interesų apsauga. Mokslinėje literatūroje nėra pasiūlyto mažojo vartojimo kreditavimo sandorių reguliavimo modelio, nėra nusistovėjusio požiūrio į priešingų skolininko ir kreditorių interesų balansavimą ar mažojo... [toliau žr. visą tekstą]

Vartojimo kreditavimas yra įprastas namų ūkių poreikių finansavimo šaltinis, neišvengiamas daugeliui jų. Kreditavimo rinkos pokyčiai, atsiradę ekonomikos sunkmečio laikotarpiu 2008-2009 metais, lemia ypatingai didelį šios tematikos mokslinių tyrimų aktualumą. Tradicines bankų ar kredito unijų teikiamas vartojimo paskolas papildė nauji skolinimo instrumentai, tarp kurių populiarūs ir žinomi – mažieji vartojimo kreditai, pasižymintys aukšta palūkanų norma ir lengvu prieinamumu. Dėl mažųjų vartojimo kreditų populiarumo tarp socialiai pažeidžiamų asmenų ir augimo, šie sandoriai tapo reguliavimo objektu. Reguliuotojui čia kyla sudėtingas uždavinys subalansuoti reguliavimo objekto – mažojo vartojimo kreditavimo sandorio šalių (skolininko ir kreditoriaus) interesus šio sandorio proceso metu. Baltijos šalyse, įskaitant ir Lietuvoje, mažojo vartojimo kreditavimo sandoriai ir jų reguliavimas yra visiškai mokslininkų netyrinėtas reiškinys.Mokslinės literatūros analizė parodė, kad tyrėjai nesutaria ar visumoj mažieji vartojimo kreditai labiau padeda vartotojams, ar yra jiems labiau žalingi. Dažnai moksliniai tyrimai neatsako į klausimą - kaip reguliuoti mažojo vartojimo kreditavimo sandorius, kad būtų užtikrintas kredito prieinamumas ir subalansuota skolininko bei kreditorių interesų apsauga. Mokslinėje literatūroje nėra pasiūlyto mažojo vartojimo kreditavimo sandorių reguliavimo modelio, nėra nusistovėjusio požiūrio į priešingų skolininko ir kreditorių interesų balansavimą ar mažojo... [toliau žr. visą tekstą] / Consumer credit has become a common source of finance for households, inevitable for the majority of them. Developments of credit markets that emerged as a result of economic hardship in 2008-2009, leads to the high relevance of the scientific researches on the topic. Traditional consumer loans provided by banks or credit unions are supplemented by the new debt instruments. The most popular and well known ones are payday loans (small amount, short term and high cost loans), having the high credit price (in APR terms) and are easily accessible. Because of such rapid growth and popularity of payday loans among socially vulnerable borrowers, these transactions became the object of regulation. The regulator here faces a very complex task - to balance the interests of the payday loan transaction parties (borrower and lender) throughout the process of the transaction. In the Baltic States, including Lithuania, payday lending transactions and their regulation is a well underexplored field of scientific research. Analysis of the scientific literature has revealed that there is a general disagreement on whether payday loans benefit or harm borrowers? Usually studies does not provide complete answer on how to regulate payday lending transactions in order to ensure access to credit and balance the interests of creditors and debtors. No one has offered a model of payday lending transactions regulation yet. Moreover, there is no generally established view on the balance of borrowers’ and... [to full text]

Pervasive computing envisions an environment in which we are surrounded by many embedded computer devices. The existence of those networked devices provides us with a mobile, spontaneous and dynamic way to access various resources provided by different (security policy) domains. In recent years, we have witnessed the evolutionary development of numerous multiple domain applications. One of the richest examples is pervasive environments. Typi- cally, the conventional approach to secure access over multiple domains is to implement a unique trusted infrastructure, extending local identity or capa- bility based security systems and combining them with cross-domain authen- tication mechanisms. However, this does not adequately meet the security requirements of communicating with unknown players in pervasive environ- ments. Moreover, it is infeasible to define a global trust infrastructure and a set of assumptions that every player will trust in the multiple domain context. A powerful design technique to address those new security challenges posed by pervasive environments is to understand them from a domain perspective. This thesis presents Localisation of Trust (LoT), an architectural frame- work designed to address the security need of how to talk to correct strangers in pervasive environments. Based on the localising trust security principle, LoT provides a generic platform for building access control over multiple do- mains from two ends: authentication and authorisation. Firstly, LoT proposes a two-channel authentication protocol to replace traditional (strong) identity- based authentication protocols by exploring desirable contextual information for different pervasive applications. Then, delegation and localised authenti- cation are deployed to achieve authorisation in pervasive environments. The heart of this different semantic is to let the right domain get involved with its local players’ interactions by helping them to convert a “token” to a usable 2 access capability, whilst keeping revocation in mind. This is done by introduc- ing a domain-oriented Encryption-Based Access Control method, using ideas borrowed for Identity-based Encryption. The second part of this thesis describes several specific mechanisms and protocols including a Dual Capabilities Model to achieve the required anti- properties for LoT. Although novel, they are intended primarily as an existence proof rather than being claimed to be ideal. Depending upon the precise application and context, other mechanisms may be better. Most importantly, the architecture-focused LoT provides such a flexibility by introducing multiple domains as a primary concern but leaving untouched the security protocols underlying each single domain and system implementation. Finally, a single domain scenario, guest access, is examined with the light of LoT. The purpose of doing so is to enhance the understanding of domain and other concepts described in LoT and demonstrate the effectiveness and efficiency of LoT for the scenarios chosen.

Improving our understanding of the factors that shape the demography of populations now requires that we consider no event in isolation, and instead express current performance as a product of previous events and processes. Patterns of site choice and dispersal likely underpin a large proportion of the variation in reproductive success among individuals, but the consequences of dispersal decisions may only become apparent many months later at a separate stage of the annual cycle Only by studying the interactions among seasons can we determine how differences in annual routine translate into asymmetries in fitness, and subsequently apply this understanding to processes occurring at the population level. This thesis begins with a review of the phenomena known as carry-over effects (COEs; Chapter 2), where I find evidence to support their occurrence in a multitude of taxa and identify previously unconsidered drivers of carry-over effects that could potentially explain their widespread nature. The remainder of this thesis comprises empirical work using light-bellied Brent geese (Branta bernicla hrota) as a model system to study these processes. In Chapter 3 I show evidence of a COE in Brent geese mediated by body condition, but in addition demonstrate how the strength of this effect is moderated by downstream climatic conditions operating in a density-independent fashion. Chapter 4 describes the development of novel polymorphic microsatellite loci to be used in population genetic and parentage studies. In Chapter 5 I show that light-bellied Brent geese are highly site faithful and that this fidelity has a cultural basis. Finally in Chapter 6 I characterize patterns of mate choice, and investigate potential consequences of this pattern in light of the observed site fidelity, in terms of risk of inbreeding. Collectively my results demonstrate the utility of combining long-term datasets with genetic pedigrees to investigate patterns of dispersal in a migratory species. Moreover they highlight the necessity to study individual performance in the context of the entire annual cycle in order to fully characterize the nature and strength of fitness determinants operating at multiple stages in a migratory species.