System design and resource management in the next-generation integrated WLAN and 3G cellular networks

Next-generation integrated wireless local area network (WLAN) and 3G cellular networks aim to take advantage of the roaming ability in a cellular network and the high data rate services of a WLAN. To ensure successful implementation of an integrated network, many issues must be carefully addressed, including network architecture design, resource management, quality-of-service (QoS), call admission control (CAC) and mobility management. ^ This dissertation focuses on QoS provisioning, CAC, and the network architecture design in the integration of WLANs and cellular networks. First, a new scheduling algorithm and a call admission control mechanism in IEEE 802.11 WLAN are presented to support multimedia services with QoS provisioning. The proposed scheduling algorithms make use of the idle system time to reduce the average packet loss of realtime (RT) services. The admission control mechanism provides long-term transmission quality for both RT and NRT services by ensuring the packet loss ratio for RT services and the throughput for non-real-time (NRT) services. ^ A joint CAC scheme is proposed to efficiently balance traffic load in the integrated environment. A channel searching and replacement algorithm (CSR) is developed to relieve traffic congestion in the cellular network by using idle channels in the WLAN. The CSR is optimized to minimize the system cost in terms of the blocking probability in the interworking environment. Specifically, it is proved that there exists an optimal admission probability for passive handoffs that minimizes the total system cost. Also, a method of searching the probability is designed based on linear-programming techniques. ^ Finally, a new integration architecture, Hybrid Coupling with Radio Access System (HCRAS), is proposed for lowering the average cost of intersystem communication (IC) and the vertical handoff latency. An analytical model is presented to evaluate the system performance of the HCRAS in terms of the intersystem communication cost function and the handoff cost function. Based on this model, an algorithm is designed to determine the optimal route for each intersystem communication. Additionally, a fast handoff algorithm is developed to reduce the vertical handoff latency.^

Traffic congestion control in communication networks

Next generation networks are characterized by ever increasing complexity, intelligence, heterogeneous technologies and increasing user expectations. Telecommunication networks in particular have become truly global, consisting of a variety of national and regional networks, both wired and wireless. Consequently, the management of telecommunication networks is becoming increasingly complex. In addition, network security and reliability requirements require additional overheads which increase the size of the data records. This in turn causes acute network traffic congestions. There is no single network management methodology to control the various requirements of today's networks, and provides a good level of Quality of Service (QoS), and network security. Therefore, an integrated approach is needed in which a combination of methodologies can provide solutions and answers to network events (which cause severe congestions and compromise the quality of service and security). The proposed solution focused on a systematic approach to design a network management system based upon the recent advances in the mobile agent technologies. This solution has provided a new traffic management system for telecommunication networks that is capable of (1) reducing the network traffic load (thus reducing traffic congestion), (2) overcoming existing network latency, (3) adapting dynamically to the traffic load of the system, (4) operating in heterogeneous environments with improved security, and (5) having robust and fault tolerance behavior. This solution has solved several key challenges in the development of network management for telecommunication networks using mobile agents. We have designed several types of agents, whose interactions will allow performing some complex management actions, and integrating them. Our solution is decentralized to eliminate excessive bandwidth usage and at the same time has extended the capabilities of the Simple Network Management Protocol (SNMP). Our solution is fully compatible with the existing standards.

Synthetic studies of azulenyl and pseudoazulenyl nitrones

Free radicals have been implicated in various pathological conditions such as, stroke, aging and ischemic heart disease (IHD), as well as neurodegenerative diseases like Alzheimer’s, Parkinson’s, and Huntington’s disease. The role of antioxidants in protection from the harmful effects of free radicals has long been recognized. Trapping extremely reactive free radicals and eliminating them from circulation has been shown to be effective in animal models. Nitrone-based free radical traps have been extensively explored in biological systems. Examples include nitrones such as PBN, NXY-059, MDL-101,002, DMPO and EMPO. However, these nitrones have extremely high oxidation potentials as compared to natural antioxidants such as Vitamin E (α-tocopherol), and glutathione. Becker et al. (1995) synthesized novel azulenyl nitrones, which were shown to have oxidation potentials much lower than that of any of the previously reported nitrone based spin traps. Another azulenyl nitrone derivative, stilbazulenyl nitrone (STAZN), was shown to have an even lower oxidation potential within the range of natural antioxidants. STAZN, a second generation free radical trap, was found to be markedly superior than the two most studied nitrones, PBN and NXY-059, in animal models of cerebral ischemia and in an in vitro assay of lipid peroxidation. In this study, a third generation azulenyl nitrone was synthesized with an electron donating group on the previously synthesized STAZN derivative with the aim to lower the oxidation potential even more. Pseudoazulenes, because of the presence of an annular heteroatom, have been reported to possess even lower oxidation potential than that of the azulenyl counterpart. Therefore, pseudoazulenyl nitrones were synthesized for the first time by extracting and elaborating valtrate from the roots of Centranthus ruber (Red valerian or Jupiter’s beard). Several pseudoazulenyl nitrones were synthesized by using a facile experimental protocol. The physical and biological properties of these pseudoazulenyl nitrones can be easily modified by simply changing the substituent on the heteroatom. Cyclic voltammetry experiments have shown that these pseudoazulenyl nitrones do indeed have low oxidation potentials. The oxidation potential of these nitrones was lowered even more by preparing derivatives bearing an electron donating group at the 3-position of the five membered ring of the pseudoazulenyl nitrone.

Improved Annual Average Daily Traffic (AADT) estimation for local roads using parcel-level travel demand modeling

Annual Average Daily Traffic (AADT) is a critical input to many transportation analyses. By definition, AADT is the average 24-hour volume at a highway location over a full year. Traditionally, AADT is estimated using a mix of permanent and temporary traffic counts. Because field collection of traffic counts is expensive, it is usually done for only the major roads, thus leaving most of the local roads without any AADT information. However, AADTs are needed for local roads for many applications. For example, AADTs are used by state Departments of Transportation (DOTs) to calculate the crash rates of all local roads in order to identify the top five percent of hazardous locations for annual reporting to the U.S. DOT. ^ This dissertation develops a new method for estimating AADTs for local roads using travel demand modeling. A major component of the new method involves a parcel-level trip generation model that estimates the trips generated by each parcel. The model uses the tax parcel data together with the trip generation rates and equations provided by the ITE Trip Generation Report. The generated trips are then distributed to existing traffic count sites using a parcel-level trip distribution gravity model. The all-or-nothing assignment method is then used to assign the trips onto the roadway network to estimate the final AADTs. The entire process was implemented in the Cube demand modeling system with extensive spatial data processing using ArcGIS. ^ To evaluate the performance of the new method, data from several study areas in Broward County in Florida were used. The estimated AADTs were compared with those from two existing methods using actual traffic counts as the ground truths. The results show that the new method performs better than both existing methods. One limitation with the new method is that it relies on Cube which limits the number of zones to 32,000. Accordingly, a study area exceeding this limit must be partitioned into smaller areas. Because AADT estimates for roads near the boundary areas were found to be less accurate, further research could examine the best way to partition a study area to minimize the impact.^

Synthetic Studies of Azulenyl and Pseudoazulenyl Nitrones

Free radicals have been implicated in various pathological conditions such as, stroke, aging and ischemic heart disease (IHD), as well as neurodegenerative diseases like Alzheimer’s, Parkinson’s, and Huntington’s disease. The role of antioxidants in protection from the harmful effects of free radicals has long been recognized. Trapping extremely reactive free radicals and eliminating them from circulation has been shown to be effective in animal models. Nitrone-based free radical traps have been extensively explored in biological systems. Examples include nitrones such as PBN, NXY-059, MDL-101,002, DMPO and EMPO. However, these nitrones have extremely high oxidation potentials as compared to natural antioxidants such as Vitamin E (á-tocopherol), and glutathione. Becker et al. (1995) synthesized novel azulenyl nitrones, which were shown to have oxidation potentials much lower than that of any of the previously reported nitrone based spin traps. Another azulenyl nitrone derivative, stilbazulenyl nitrone (STAZN), was shown to have an even lower oxidation potential within the range of natural antioxidants. STAZN, a second generation free radical trap, was found to be markedly superior than the two most studied nitrones, PBN and NXY-059, in animal models of cerebral ischemia and in an in vitro assay of lipid peroxidation. In this study, a third generation azulenyl nitrone was synthesized with an electron donating group on the previously synthesized STAZN derivative with the aim to lower the oxidation potential even more. Pseudoazulenes, because of the presence of an annular heteroatom, have been reported to possess even lower oxidation potential than that of the azulenyl counterpart. Therefore, pseudoazulenyl nitrones were synthesized for the first time by extracting and elaborating valtrate from the roots of Centranthus ruber (Red valerian or Jupiter’s beard). Several pseudoazulenyl nitrones were synthesized by using a facile experimental protocol. The physical and biological properties of these pseudoazulenyl nitrones can be easily modified by simply changing the substituent on the heteroatom. Cyclic voltammetry experiments have shown that these pseudoazulenyl nitrones do indeed have low oxidation potentials. The oxidation potential of these nitrones was lowered even more by preparing derivatives bearing an electron donating group at the 3-position of the five membered ring of the pseudoazulenyl nitrone.

Our own language: Scots verse translation and the second-generation Scottish renaissance

This thesis examines the role of Scots language verse translation in the second-generation or post-war Scottish Renaissance. The translation of European poetry into Scots was of central importance to the first-generation Scottish Renaissance of the nineteen twenties and thirties. As Margery Palmer McCulloch has shown, the wider cultural climate of Anglo-American modernism was key to MacDiarmid’s conception of the interwar Scottish Renaissance. What was the effect on second-generation poet-translators as the modernist moment passed? Are the many translations undertaken by the younger poets who emerged in the course of the nineteen forties and fifties a faithful reflection of this cultural inheritance? To what extent are they indicative of a new set of priorities and international influences? The five principal translators discussed in this thesis are Douglas Young (1913-1973), Sydney Goodsir Smith (1915-1975), Robert Garioch (1909-1981), Tom Scott (1918-1995) and William J. Tait (1918-1992). Each is the subject of a chapter, in many cases providing the first or most extensive treatment of particular translations. While the pioneering work of John Corbett, Bill Findlay and J. Derrick McClure, among other scholars, has drawn attention to the long history of literary translation into Scots, this thesis is the first extended critical work to take the verse translations of the post-MacDiarmid makars as its subject. The nature and extent of MacDiarmid’s influence is considered throughout, as are the wider discourses around language and translation in twentieth-century Scottish poetry. Critical engagement with a number of key insights from theoretical translation studies helps to situate these writers’ work in its global context. This thesis also explores the ways in which the specific context of Scots translation allows scholars to complicate or expand upon theories of translation developed in other cultural situations (notably Lawrence Venuti’s writing on domestication and foreignisation). The five writers upon whom this thesis concentrates were all highly individual, occasionally idiosyncratic personalities. Young’s polyglot ingenuity finds a foil in Garioch’s sharp, humane wit. Goodsir Smith’s romantic ironising meets its match in Scott’s radical certainty of cause. Tait’s use of the Shetlandic tongue sets him apart. Nonetheless, despite the great variety of style, form and tone shown by each of these translators, this thesis demonstrates that there are meaningful links to be made between them and that they form a unified, coherent group in the wider landscape of twentieth-century Scottish poetry. On the linguistic level, each engaged to some extent in the composition of a ‘synthetic’ or ‘plastic’ language deriving partly from literary sources, partly from the spoken language around them. On a more fundamental level, each was committed to enriching this language through translation, within which a number of key areas of interest emerge. One of the most important of these key areas is Gaelic – especially the poetry of Sorley MacLean, which Young, Garioch and Goodsir Smith all translated into Scots. This is to some extent an act of solidarity on the part of these Scots poets, acknowledging a shared history of marginalisation as well as expressing shared hopes for the future. The same is true of Goodsir Smith’s translations from a number of Eastern European poets (and Edwin Morgan’s own versions, slightly later in the century). The translation of verse drama by poets is another key theme sustained throughout the thesis, with Garioch and Young attempting to fill what they perceived as a gap in the Scots tradition through translation from other languages (another aspect of these writers’ legacy continued by Morgan). Beyond this, all of the writers discussed in this thesis translated extensively from European poetries from Ancient Greece to twentieth-century France. Their reasons for doing so were various, but a certain cosmopolitan idealism figures highly among them. So too does a desire to see Scotland interact with other European nations, thus escaping the potentially narrowing influence of post-war British culture. This thesis addresses the legacy of these writers’ translations, which, it argues, continue to exercise a perceptible influence on the course of poetry in Scotland. This work constitutes a significant contribution to a much-needed wider critical re-assessment of this pivotal period in modern Scottish writing, offering a fresh perspective on the formal and linguistic merits of these poets’ verse translations. Drawing upon frequently obscure book, pamphlet and periodical sources, as well as unpublished manuscripts in the National Library of Scotland and the Shetland Archives, this thesis breaks new ground in its investigation of the role of Scots verse translation in the second-generation Scottish Renaissance.

Hydroalumination of Thioacetylenes: A Versatile Generation and Reactions of -Aluminate Sulfides Intermediates

Hydroalumination of thioacetylenes using DIBAL-H and lithium di-(isobutyl)-n-(butyl)-aluminate hydride (Zweifel's reagent), followed by addition of water, furnished exclusively the (Z)- and (E)-vinyl sulfides, respectively. The regio- and stereochemistry of the intermediates generated, (Z)- and (E)-phenylthio vinyl alanates, were determined by capture with iodine, which afforded the corresponding (E)- and (Z)-1-iodo-1-phenylthio-2-organoyl ethenes. Reactions of the (E)-iodo(thio)ketene acetals with n-BuLi followed by addition of hexanal afforded the (Z)-phenylthio allylic alcohol, while the (Z)-iodo(thio)ketene acetals under similar reactions conditions gave the (E)-phenylthio allylic alcohol exclusively.

Generation and screening of natural product-like compounds for antibiotic discovery

Avec l’apparition de plus en plus de souches de bactérie résistante aux antibiotiques, le développement de nouveaux antibiotiques est devenu une important problématique pour les agences de santé. C’est pour cela que la création de nouvelles plateformes pour accélérer la découverte de médicaments est devenu un besoin urgent. Dans les dernières décennies, la recherche était principalement orientée sur la modification de molécules préexistantes, la méta-analyse d’organismes produisant des molécules activent et l’analyse de librairies moléculaires pour trouver des molécules synthétiques activent, ce qui s’est avéré relativement inefficace. Notre but était donc de développer de nouvelles molécules avec des effets thérapeutiques de façon plus efficace à une fraction du prix et du temps comparé à ce qui se fait actuellement. Comme structure de base, nous avons utilisé des métabolites secondaires qui pouvaient altérer le fonctionnement des protéines ou l’interaction entre deux protéines. Pour générer ces molécules, j’ai concentré mes efforts sur les terpènes, une classe de métabolites secondaires qui possède un large éventail d’activités biologiques incluant des activités antibactériennes. Nous avons développé un système de chromosome artificiel de levure (YAC) qui permet à la fois l’assemblage directionnel et combinatoire de gènes qui permet la création de voies de biosynthèse artificielles. Comme preuve de concept, j’ai développé des YACs qui contiennent les gènes pour l’expression des enzymes impliquées dans la biosynthèse de la -carotène et de l’albaflavenone et produit ces molécules avec un haut rendement. Finalement, Des YACs produits à partir de librairies de gènes ont permis de créer une grande diversité de molécules.

Generation and screening of natural product-like compounds for antibiotic discovery

Avec l’apparition de plus en plus de souches de bactérie résistante aux antibiotiques, le développement de nouveaux antibiotiques est devenu une important problématique pour les agences de santé. C’est pour cela que la création de nouvelles plateformes pour accélérer la découverte de médicaments est devenu un besoin urgent. Dans les dernières décennies, la recherche était principalement orientée sur la modification de molécules préexistantes, la méta-analyse d’organismes produisant des molécules activent et l’analyse de librairies moléculaires pour trouver des molécules synthétiques activent, ce qui s’est avéré relativement inefficace. Notre but était donc de développer de nouvelles molécules avec des effets thérapeutiques de façon plus efficace à une fraction du prix et du temps comparé à ce qui se fait actuellement. Comme structure de base, nous avons utilisé des métabolites secondaires qui pouvaient altérer le fonctionnement des protéines ou l’interaction entre deux protéines. Pour générer ces molécules, j’ai concentré mes efforts sur les terpènes, une classe de métabolites secondaires qui possède un large éventail d’activités biologiques incluant des activités antibactériennes. Nous avons développé un système de chromosome artificiel de levure (YAC) qui permet à la fois l’assemblage directionnel et combinatoire de gènes qui permet la création de voies de biosynthèse artificielles. Comme preuve de concept, j’ai développé des YACs qui contiennent les gènes pour l’expression des enzymes impliquées dans la biosynthèse de la -carotène et de l’albaflavenone et produit ces molécules avec un haut rendement. Finalement, Des YACs produits à partir de librairies de gènes ont permis de créer une grande diversité de molécules.

Thermal decomposition of the synthetic hydrotalcite iowaite

The thermal stability and thermal decomposition pathways for synthetic iowaite have been determined using thermogravimetry in conjunction with evolved gas mass spectrometry. Chemical analysis showed the formula of the synthesised iowaite to be Mg6.27Fe1.73(Cl)1.07(OH)16(CO3)0.336.1H2O and X-ray diffraction confirms the layered structure. Dehydration of the iowaite occurred at 35 and 79°C. Dehydroxylation occurred at 254 and 291°C. Both steps were associated with the loss of CO2. Hydrogen chloride gas was evolved in two steps at 368 and 434°C. The products of the thermal decomposition were MgO and a spinel MgFe2O4. Experimentally it was found to be difficult to eliminate CO2 from inclusion in the interlayer during the synthesis of the iowaite compound and in this way the synthesised iowaite resembled the natural mineral.

The Behavior of Hydroxyl Units of Synthetic Goethite and its Dehydroxylated Product Hematite

The behavior of the hydroxyl units of synthetic goethite and its dehydroxylated product hematite was characterized using a combination of Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) during the thermal transformation over a temperature range of 180-270 degrees C. Hematite was detected at temperatures above 200 degrees C by XRD while goethite was not observed above 230 degrees C. Five intense OH vibrations at 3212-3194, 1687-1674, 1643-1640, 888-884 and 800-798 cm(-1), and a H2O vibration at 3450-3445 cm(-1) were observed for goethite. The intensity of hydroxyl stretching and bending vibrations decreased with the extent of dehydroxylation of goethite. Infrared absorption bands clearly show the phase transformation between goethite and hematite: in particular. the migration of excess hydroxyl units from goethite to hematite. Two bands at 536-533 and 454-452 cm(-1) are the low wavenumber vibrations of Fe-O in the hematite structure. Band component analysis data of FTIR spectra support the fact that the hydroxyl units mainly affect the a plane in goethite and the equivalent c plane in hematite.

Air pollution levels measured at traffic hot spots : Brisbane urban corridor study

Air pollution levels were monitored continuously over a period of 4 weeks at four sampling sites along a busy urban corridor in Brisbane. The selected sites were representative of industrial and residential types of urban environment affected by vehicular traffic emissions. The concentration levels of submicrometer particle number, PM2.5, PM10, CO, and NOx were measured 5-10 meters from the road. Meteorological parameters and traffic flow rates were also monitored. The data were analysed in terms of the relationship between monitored pollutants and existing ambient air quality standards. The results indicate that the concentration levels of all pollutants exceeded the ambient air background levels, in certain cases by up to an order of magnitude. While the 24-hr average concentration levels did not exceed the standard, estimates for the annual averages were close to, or even higher than the annual standard levels.