No description available.

Heterogeneous cellular networks (HCNs) – comprising traditional macro base stations (BSs) and heterogeneous infrastructure such as microcells, picocells, femtocells and distributed antennas – are fast becoming a cost-effective and essential way of handling explosive wireless data traffic demands. Up until now, little basic research has been done on the fundamentals of managing so much infrastructure – much of it unplanned – together with the carefully planned macro-cellular network. This dissertation addresses the key technical challenges of inter-cell interference management in this new network paradigm. This dissertation first studies uplink femtocell access control in uncoordinated two-tier networks, i.e. where the femtocells cannot coordinate with macrocells. Closed access allows registered home users to monopolize their own femtocell and its backhaul connection, but also results in severe interference between femtocells and nearby unregistered macro users. Open access reduces such interference by handing over such users, at the expense of femtocell resource sharing. In the first analytical work on this topic, we studied the best femtocell access technique from the perspectives of both network operators and femtocell owners, and show that it is strongly contingent on parameters such as multiple access schemes (i.e. orthogonal vs. non- orthogonal) and cellular user density (in TDMA/OFDMA). To study coordinated algorithms whose success depends heavily on the rate and delay (vs. user mobility) of inter-cell overhead sharing, this dissertation develops various models of overhead signaling in general HCNs and derives the overhead quality contour – the achievable set of overhead packet rate and delay – under general assumptions on overhead arrivals and different overhead signaling methods (backhaul and/or wireless). The overhead quality contour is further simplified for two widely used models of overhead arrivals: Poisson and deterministic. Based on the overhead quality contour that is applicable to generic coordinated techniques, this dissertation develops a novel analytical framework to evaluate downlink coordinated multi-point (CoMP) schemes in HCNs. Combined with the signal-to-interference-plus-noise-ratio (SINR) characterization, this framework can be used for a class of CoMP schemes without user data sharing. As an example, we apply it to downlink CoMP inter-cell interference cancellation (ICIC), after deriving SINR results for it using the spatial Poisson Point Process (PPP) to capture the uncertainty in base station locations. / text

The objective of this work is to design a damping controller for a thyristor controlled series capacitor (TCSC) to damp robustly inter-area oscillations in power systems with an immunity against sub-synchronous resonance (SSR) oscillations which may lead to torsional oscillations. The new control strategy has two main loops; an SSR mitigation loop and a bang-bang loop, the latter is designed with the aim of damping inter-area oscillations with a settling time 8-10 sec. The appropriate selection of the bang-bang series compensation component, ∆KC, is addressed by considering the Eigen analysis of the generators’ shafts and an impedance scan of the series compensated line for different compensation levels. The SSR mitigation loop is designed with the aim of providing a fine tune control signal to be added to the main value of the inserted series compensation (KC), to damp SSR oscillations and related torsional mode of oscillations. To address this issue, a new observer-based multiple model adaptive control algorithm is designed to control a multi-stage TCSC. The SSR modelling challenges associated with the load dynamics and with the insertion of the series compensation into the transmission system are overcome by a fine tuning control loop, which adjusts the resultant series compensation (KC). Considering the integration and coordination of oscillation damping and distance protection in the transmission system, a new adaptive technique must be designed to control the distance relay (DR) to prevent its mal operation (during the damping process). The new strategy is illustrated through an 11-bus 4-machine 2-area benchmark power system. The performance and advantages of the new algorithm are validated using time domain simulation via PSCAD software.

No description available.

A wound- and insect-inducible expression system for transgenic plants was developed. Specifically, I demonstrate wound- and insect-inducible, localized gene expression driven by the potato proteinase inhibitor II (pinII)-promoter in transformed Arabidopsis, tobacco and white spruce. As reporter and target genes driven by the pinII-promoter, I used the GUS gene and a terpenoid synthase gene, respectively. In addition, I found that the pinII-promoter drives trichome-specific, systemically-induced gene expression in tobacco and Arabidopsis. Finally, I demonstrate that the pinII–promoter, when transformed into Arabidopsis, is extremely sensitive to subtle, low-impact stress treatment. This latter finding prompted me to use, in the second part of my thesis, the pinII-promoter in conjunction with GUS reporter gene expression to test if intact Arabidopsis plants can respond to exposure to monoterpene volatiles. My experiments using the pinII–promoter GUS reporter system clearly established that Arabidopsis plants respond to the exposure of the monoterpene volatiles tested. It is thought that monoterpenes and other volatiles can act as airborne signals between plants under stress or between distant parts of the same plant. At the outset of my thesis research, and to some extent still today, the concept of plant-plant signalling with volatiles has been met with scepticism. After establishing that Arabidopsis plants do respond in a laboratory setting to certain monoterpene volatiles, I further tested the extent of the response at the transcriptome level using a 30 K microarray platform. The gene expression analysis revealed several hundred transcripts that respond with a change of abundance in response to treatment of intact Arabidopsis plants with the monoterpenes ocimene or myrcene. Many of these transcripts were annotated as stress and defense genes including genes involved in octadecanoid signaling. Real-time PCR analyses of octadecanoid mutants confirmed a role for octadecanoid signaling in the response to the monoterpene ocimene. In addition, treatment with ocimene or myrcene caused increased levels of methyl jasmonate (MeJA) in Arabidopsis rosette leaves. However, plants treated with monoterpene prior to wounding or feeding by cabbage looper did not reveal any significant priming effect for these pre-treatments.

No description available.

No description available.

The Thesis investigates the determinants and patterns of specialisation and international trade in the manufacturing sectors of countries that are similar in terms of their technology, relative factor endowments and preferences. Chapter 1 shows that differences in country size alone can be a basis for interindustry trade in manufactures. I present a general equilibrium model in which each country has two imperfectly competitive industries which can differ in three respects: relative factor intensities, level of transport costs and demand elasticities. With positive trade costs and increasing returns to scale, each firm prefers to locate in the larger country due to the 'market access' effect. But the increase in demand for factors in the large country induces a 'production cost' effect - a rise in the wage in the large country relative to the small country to offset the locational advantage of the large country. The tension between the market access effect and production cost effect determines which industry will concentrate in which country and the pattern of inter-industry trade. Chapter 2 investigates circumstance in which technological leapfrogging between regions will occur. Input-output linkages between firms in imperfectly competitive industries create forces for agglomeration of industries in particular locations. A new technology, incompatible with the old, will not benefit from these linkages, so will typically be established in locations with little existing industry and consequently lower factor prices. Chapters 3 studies specialisation patterns in the European Union between 1968 and 1990. It investigates whether specialisation has increased in the European Union countries and analyses whether these patterns are consistent with three different strands of trade theories: the classical Heckscher-Ohlin theory, the 'new' trade theories based on increasing returns to scale, and the 'economic geography' theories based on vertical linkages between industries. I find that there is evidence of increasing specialisation in the European Union countries and there is some support for all three strands of trade theories.

No description available.

Volunteer tourism has been regarded to provide an authentic and mutually beneficial relationship between volunteer tourists and residents based on volunteering. By exploring volunteer tourists' emotional solidarity with residents, the researcher aims to uncover the social relations between volunteer tourists and residents in practice. This exploratory study was conducted in Puerto Viejo, Costa Rica during November 2012 to January 2013. Based on the two months of ethnographic field research, this research suggests that volunteer tourism may not be superior to so-called “mass tourism” in terms of building harmonious relationships between volunteer tourists and resident. In this study, volunteer tourists’ feelings of closeness were merely feelings which boosted the identity of volunteer tourists from “tourists” to “volunteers”. This article contributes to the growing body of literature on volunteer tourism by exploring the volunteer tourism experience from the perspectives of international volunteers.