A reconfigurable distributed multiagent system optimized for scalability

This thesis proposes a novel solution for optimizing the size and communication overhead of a distributed multiagent system without compromising the performance. The proposed approach addresses the challenges of scalability especially when the multiagent system is large. A modified spectral clustering technique is used to partition a large network into logically related clusters. Agents are assigned to monitor dedicated clusters rather than monitor each device or node. The proposed scalable multiagent system is implemented using JADE (Java Agent Development Environment) for a large power system. The performance of the proposed topology-independent decentralized multiagent system and the scalable multiagent system is compared by comprehensively simulating different fault scenarios. The time taken for reconfiguration, the overall computational complexity, and the communication overhead incurred are computed. The results of these simulations show that the proposed scalable multiagent system uses fewer agents efficiently, makes faster decisions to reconfigure when a fault occurs, and incurs significantly less communication overhead. The proposed scalable multiagent system has been coupled with a scalable reconfiguration algorithm for an electric power system attempting to minimize the number of switch combination explored for reconfiguration. The reconfiguration algorithm reconfigures a power system while maintaining bus voltages within limits specified by constraints

A PIPELINED APPROACH FOR FPGA IMPLEMENTATION OF BI MODAL BIOMETRIC PATTERN RECOGNITION

ABSTRACT A Biometric system is essentially a pattern recognition system that makes use of biometric traits to recognize individuals. Systems which are built upon multiple sources of information for establishing identity which are known as multimodal biometric systems can overcome some of the limitations like noisy captured data, intra class variations etc… In this paper a Bi modal biometric system of iris and palm print based on Wavelet Packet Transform (WPT), gabor filters and a neural classifier implemented in FPGA is described. Iris is the unique observable visible feature present in the detailed texture of each eye. Palmprint is referred to the textural data like principal lines wrinkles and ridges present in the palm. The visible texture of a person's iris and palm print is encoded into a compact sequence of 2-D wavelet packet coefficients constituting a biometric signature or a feature vector code. In this paper, a novel multi-resolution approach based on WPT for recognition of iris and palmprint is proposed. With an adaptive threshold, WPT sub image coefficients are quantized into 1, 0 or -1 as biometric signature resulting in the size of biometric signature as 960 bits. The combined pattern vector of palm print features and iris features are formed using fusion at feature level and applied to the pattern classifier. The Learning Vector Quantization neural network is used as pattern classifier and a recognition rate of 97.22% is obtained. A part of the neural network is implemented for input data of 16 dimensions and 12 input classes and 8 output classes, using virtex-4 xc4vlx15 device. This system can complete recognition in 3.25 microseconds thus enabling it being suitable for real time pattern recognition tasks

Functional colloidal surface assemblies: Classical optics meets template-assisted self-assembly

Abstract: When noble metals particles are synthesized with progressively smaller dimensions, strikingly novel optical properties arise. For nanoscale particles, collective disturbances of the electron density known as localized surface plasmons resonances can arise, and these resonances are utilized in a variety of applications ranging from surface-enhanced molecular spectroscopy and sensing to photothermal cancer therapy to plasmon-driven photochemistry. Central to all of these studies is the plasmon’s remarkable ability to process light, capturing and converting it into intense near fields, heat, and even energetic carriers at the nanoscale. In the past decade, we have witnessed major advances in plasmonics which is directly linked with the much broader field of (colloidal) nanotechnology. These breakthroughs span from plasmon lasing and waveguides, plasmonic photochemistry and solar cells to active plasmonics, plasmonics nanocomposites and semiconductor plasmons. All the above-mentioned phenomena rely on precise spatial placement and distinct control over the dimensions and orientation of the individual plasmonic building blocks within complex one-, two- or three-dimensional complex arrangements. For the nanofabrication of metal nanostructures at surfaces, most often lithographic approaches, e.g. e-beam lithography or ion-beam milling are generally applied, due to their versatility and precision. However, these techniques come along with several drawbacks such as limited scalability, limited resolution, limited compatibility with silicon manufacturing techniques, damping effects due to the polycrystalline nature of the metal nanostructures and low sample throughput. Thus, there is a great demand for alternative approaches for the fabrication of metal nanostructures to overcome the above-mentioned limitations. But why colloids? True three-dimensionality, lower damping, high quality modes due to mono-dispersity, and the absence of grain boundaries make the colloidal assembly an especially competitive method for high quality large-scale fabrication. On top of that, colloids provide a versatile platform in terms of size, shape, composition and surface modification and dispersion media. 540The combination of directed self-assembly and laser interference lithography is a versatile admixture of bottom-up and top-down approaches that represents a compelling alternative to commonly used nanofabrication methods. The objective of this thesis is to focus on large area fabrication of emergent spectroscopic properties with high structural and optical quality via colloidal self-assembly. We focus on synergy between optical and plasmonic effects such as: (i) coupling between localized surface plasmon resonance and Bragg diffraction leading to surface lattice resonance; (ii) strong light matter interaction between guided mode resonance and collective plasmonic chain modes leading to hybrid guided plasmon modes, which can further be used to boost the hot-electron efficiency in a semiconducting material; (iii) similarly, bilayer nanoparticle chains leading to chiro-optical effects. Following this scope, this thesis introduces a real-time tuning of such exclusive plasmonic-photonic (hybrid) modes via flexible template fabrication. Mechanical stimuli such as tensile strain facilitate the dynamic tuning of surface lattice resonance and chiro-optical effects respectively. This expands the scope to curb the rigidity in optical systems and ease the integration of such systems with flexible electronics or circuits.:Contents Abstract Kurzfassung Abbreviations 1. Introduction and scope of the thesis 1.1. Introduction 1.1.1. Classical optics concepts 1.1.2. Top down fabrication methods and their challenges 1.1.3. Template-assisted self-assembly 1.1.4. Functional colloidal surface assemblies 1.2. Scope of the thesis 2. Results and Discussion 2.1. Mechanotunable Surface Lattice Resonances in the Visible Optical Range by Soft Lithography Templates and Directed Self-Assembly 2.1.1. Fabrication of flexible 2D plasmonic lattice 2.1.2. Investigation of the influence of particle size distribution on SLR quality 2.1.3. Band diagram analysis of 2D plasmonic lattice 2.1.4. Strain induced tuning of SLR 2.1.5. SEM and force transfer analysis in 2D plasmonic lattice under various strain 2.2. Hybridized Guided-Mode Resonances via Colloidal Plasmonic Self-Assembled Grating 2.2.1. Fabrication of hybrid opto-plasmonic structure via template assisted self-assembly 2.2.2. Comparison of optical band diagram of three (plasmonic, photonic and hybrid) different structures in TE and TM modes 2.2.3. Simulative comparison of optical properties of hybrid opto-plasmonic NP chains with a grating of metallic gold bars 2.2.4. Effect of cover index variation with water as a cover medium 2.3. Hot electron generation via guided hybrid modes 2.3.1. Fabrication of the hybrid GMR structure via LIL and lift-off process 2.3.2. Spectroscopic and simulative analysis of hybrid opto-plasmonic structures of different periodicities 2.3.3. Comparative study of photocurrent generation in different plasmonic structures 2.3.4. Polarization dependent response at higher wavelength 2.3.5. Directed self-assembly of gold nanoparticles within grating channels of a dielectric GMR structure supported by titanium dioxide film 2.4. Active Chiral Plasmonics Based on Geometrical Reconfiguration 2.4.1. Chiral 3D assemblies by macroscopic stacking of achiral chain substrates 3. Conclusion 4. Zusammenfassung 5. Bibliography 6. Appendix 6.1. laser interference lithography 6.2. Soft molding 6.3. Determine fill factor of plasmonic lattice 6.4. 2D plasmonic lattice of Au_BSA under strain 6.5. Characterizing order inside a 2D lattice 6.6. Template-assisted colloidal self-assembly 6.7. Out of plane lattice resonance in 1D and 2D lattices 6.8. E-Field distribution at out of plane SLR mode for 1D lattices of various periodicity with AOI 20° 6.9. Refractive index of PDMS and UV-PDMS 6.10. Refractive index measurement for sensing 6.11. Optical constants of TiO2, ma-N 405 photoresist and glass substrate measured from spectroscopic ellipsometry Acknowledgement/ Danksagung Erklärung & Versicherung List of Publication

Stochastic-Based Computing with Emerging Spin-Based Device Technologies

In this dissertation, analog and emerging device physics is explored to provide a technology platform to design new bio-inspired system and novel architecture. With CMOS approaching the nano-scaling, their physics limits in feature size. Therefore, their physical device characteristics will pose severe challenges to constructing robust digital circuitry. Unlike transistor defects due to fabrication imperfection, quantum-related switching uncertainties will seriously increase their susceptibility to noise, thus rendering the traditional thinking and logic design techniques inadequate. Therefore, the trend of current research objectives is to create a non-Boolean high-level computational model and map it directly to the unique operational properties of new, power efficient, nanoscale devices. The focus of this research is based on two-fold: 1) Investigation of the physical hysteresis switching behaviors of domain wall device. We analyze phenomenon of domain wall device and identify hysteresis behavior with current range. We proposed the Domain-Wall-Motion-based (DWM) NCL circuit that achieves approximately 30x and 8x improvements in energy efficiency and chip layout area, respectively, over its equivalent CMOS design, while maintaining similar delay performance for a one bit full adder. 2) Investigation of the physical stochastic switching behaviors of Mag- netic Tunnel Junction (MTJ) device. With analyzing of stochastic switching behaviors of MTJ, we proposed an innovative stochastic-based architecture for implementing artificial neural network (S-ANN) with both magnetic tunneling junction (MTJ) and domain wall motion (DWM) devices, which enables efficient computing at an ultra-low voltage. For a well-known pattern recognition task, our mixed-model HSPICE simulation results have shown that a 34-neuron S-ANN implementation, when compared with its deterministic-based ANN counterparts implemented with digital and analog CMOS circuits, achieves more than 1.5 ~ 2 orders of magnitude lower energy consumption and 2 ~ 2.5 orders of magnitude less hidden layer chip area

Hidden clusters: the articulation of agglomeration in City Regions

For many years, local economic development has been driven by the desire to maintain, attract and nurture clusters of economic activity in targeted industrial sectors. However, where clusters are not conventionally sector-based, public policy needs to develop alternative approaches to leverage the economic benefits and realise competitive advantage. Drawing on a study of the Sheffield City Region (SCR), the paper explores the challenge of leveraging ‘hidden’ cross-sectoral clusters, which do not fit dominant discourses of agglomeration-led growth. We posit that it is the cross-sectoral connections and networks in the SCR which represent its key strength, yet these are only partially reflected by current place marketing and policy considerations, and, in many ways, are overlooked and thus remain ‘hidden’. The paper argues that the competitive advantage of the SCR is undermined when it characterises clusters in terms of industrial sectors, and instead needs to articulate its strengths as a strategically important industrial centre. The paper concludes by drawing out a number of implications for academic theory and policy development

Light-emitting diodes as an alternative supplemental lighting source for greenhouse tomato propagation and production

Intensive year-round local production of greenhouse-grown tomatoes (Solanum lycopersicum L.) requires the use of supplemental lighting (SL) to complement solar radiation in light-limited seasonal climates. However, SL represents a large expense to greenhouse-vegetable production. Currently, energy is second only to labor as the most expensive indirect cost of production. Thus, the greenhouse industry is interested in cost-effective, energy-efficient sources of supplemental photosynthetic light to sustain steady supplies of high-quality produce during the off-season. Overhead (OH) high-pressure sodium (HPS) lamps are considered the industry standard in greenhouse SL because of their capability to deliver adequate photosynthetically active radiation (PAR) to crops. However, HPS lamps are inefficient consumers of electrical energy with a high life-cycle cost, an intense environmental impact, and an orange-biased, blue-deficient emission spectrum. Light-emitting diodes (LEDs) offer an exciting opportunity to improve energy efficiency in greenhouse lighting because their relatively low surface temperature allows them to operate in close proximity to plant tissue without overheating or scorching plants, thereby increasing availablePAR at leaf level using less input power than HPS lamps. In addition, unlike traditional light sources used in commercial greenhouses today, LEDs are solid state, robust, long-lasting, and can be designed to emit narrow-band wavelengths that can be selected to maximize photosynthesis and growth for specific crops. ^ The goal of our research is to enable U.S. greenhouse growers to transition from HPS lighting to LED technologies for supplemental photosynthetic lighting. The specific objective of this research was to evaluate LEDs as alternative SL sources for greenhouse tomato propagation and production. Three research goals were established to support my objective: 1) to compare seasonal growth responses to three red:blue ratios of LED SL vs. HPS SL vs. ambient light for the propagation of six tomato cultivars; 2) quantify plant growth, yield, and energy consumption using intracanopy lighting (ICL) with LEDs (ICL-LED) or OH-HPS lamps as different SL sources and positions for high-wire greenhouse tomato production; 3) compare crop physiological responses to different SL sources and positions [ICL-LED vs. OH-HPS vs. hybrid lighting (ICL-LED + OH-HPS)] within an indeterminate high-wire tomato canopy. ^ Supplemental lighting increased hypocotyl diameter, epicotyl length, shoot dry weight, leaf number, and leaf expansion relative to control, whereas hypocotyl elongation decreased when SL was applied. For all cultivars tested, the combination of red and blue in SL typically increased growth of tomato seedlings. Our results indicate that blue light in SL has potential to increase overall seedling growth compared to blue-deficient LED SL treatments in overcast, variable-DLI climates. Further production studies showed that the ICL-LED technology supports similar growth and yield compared to OH-HPS but at lower electrical costs (from SL only). Additionally, we found that CO2 assimilation measured under ambient environmental conditions (A), photosynthetic quantum yield (&thetas;), maximum gross CO2 assimilation (Amax) and the light-saturation point of photosynthesis were good indicators of how ICL diminishes the top-to-bottom decline in photosynthetic activity that typically occurs with OH SL. However, we did not find any yield differences among SL treatments, indicating that higher source activity from ICL does not necessarily lead to yield increases. Based on the lower energy consumption measured for ICL-LED, and, to a lesser extent, for hybrid SL, compared to OH-HPS, we concluded that replacing OH-HPS lamps with ICL-LED or hybrid SL has great potential for energy savings during high-wire greenhouse tomato production. However, our results showed that higher total canopy photosynthesis did not lead to higher yields, most likely due to a redistribution of photoassimilate partitioning to non-harvested, vegetative plant parts

Emerging gateways for Italian high tech companies to the Silicon Valley entrepreneurial ecosystem

Italian high tech firms are currently undergoing a second revolution, incorporating economic development and searching for global expansion. Emerging realities as gateways, deal flow organizations and startups incubators allows Italian technology based SMEs to get access to the huge US market. Therefore Italian brain drain to the USA can be reversed as brain gain for Italy, through a technology – bridge between these two countries. Different forms of gateways and this new strategy are analyzed in this thesi