Finite element method analysis of band gap and transmission of two-dimensional metallic photonic crystals at terahertz frequencies

Photonic band gap and transmission characteristics of 2D metallic photonic crystals at THz frequencies have been investigated using finite element method (FEM). Photonic crystals composed of metallic rods in air, in square and triangular lattice arrangements, are considered for transverse electric and transverse magnetic polarizations. The modes and band gap characteristics of metallic photonic crystal structure are investigated by solving the eigenvalue problem over a unit cell of the lattice using periodic boundary conditions. A photonic band gap diagram of dielectric photonic crystal in square lattice array is also considered and compared with well-known plane wave expansion results verifying our FEM approach. The photonic band gap designs for both dielectric and metallic photonic crystals are consistent with previous studies obtained by different methods. Perfect match is obtained between photonic band gap diagrams and transmission spectra of corresponding lattice structure

A General Framework of Large-Scale Convex Optimization Using Jensen Surrogates and Acceleration Techniques

In a world where data rates are growing faster than computing power, algorithmic acceleration based on developments in mathematical optimization plays a crucial role in narrowing the gap between the two. As the scale of optimization problems in many fields is getting larger, we need faster optimization methods that not only work well in theory, but also work well in practice by exploiting underlying state-of-the-art computing technology. In this document, we introduce a unified framework of large-scale convex optimization using Jensen surrogates, an iterative optimization method that has been used in different fields since the 1970s. After this general treatment, we present non-asymptotic convergence analysis of this family of methods and the motivation behind developing accelerated variants. Moreover, we discuss widely used acceleration techniques for convex optimization and then investigate acceleration techniques that can be used within the Jensen surrogate framework while proposing several novel acceleration methods. Furthermore, we show that proposed methods perform competitively with or better than state-of-the-art algorithms for several applications including Sparse Linear Regression (Image Deblurring), Positron Emission Tomography, X-Ray Transmission Tomography, Logistic Regression, Sparse Logistic Regression and Automatic Relevance Determination for X-Ray Transmission Tomography

Design of 2D TeraHertz band-gap photonic waveguides using an accelerated integral equation technique

This paper describes the application of the buffered block forward backward (BBFB) method to the problem of modeling 2D terahertz (THz) photonic band gap waveguides at the frequency of 3 THz. The method of moments (MoM) is applied to the integral equation (IE) formulation in order to obtain the linear system that is solved using the BBFB technique. The waveguide dimensions are obtained using the gap map technique

Trust-Promoting Seals in Green Information Systems: The Case of Smart Meters and Privacy

Green Information Systems (IS) often require to obtain data in order to assess environmental outcomes and improve sustainable behaviours. As a result, privacy concerns can act as a barrier to the utilization of Green IS. We explore the case of smart meters, which track users’ personal energy usage data and provide real-time information, thus allowing users to reduce energy consumption. In this research-in-progress paper, we report on the development of a research model and experimental design to test the impact of trust seals, which can help to build trust and alleviate privacy concerns. For this reason, we refer to green energy and privacy seals that assess and certify the energy efficiency and privacy practices of companies. We further explore opt-out mechanisms, which give consumers the possibility to opt out of smart meter data collection that can also lead to a reduction of consumers’ privacy concerns with smart meters

PERFORMANCE ANALYSIS AND OPTIMIZATION OF QUERY-BASED WIRELESS SENSOR NETWORKS

This dissertation is concerned with the modeling, analysis, and optimization of large-scale, query-based wireless sensor networks (WSNs). It addresses issues related to the time sensitivity of information retrieval and dissemination, network lifetime maximization, and optimal clustering of sensor nodes in mobile WSNs. First, a queueing-theoretic framework is proposed to evaluate the performance of such networks whose nodes detect and advertise significant events that are useful for only a limited time; queries generated by sensor nodes are also time-limited. The main performance parameter is the steady state proportion of generated queries that fail to be answered on time. A scalable approximation for this parameter is first derived assuming the transmission range of sensors is unlimited. Subsequently, the proportion of failed queries is approximated using a finite transmission range. The latter approximation is remarkably accurate, even when key model assumptions related to event and query lifetime distributions and network topology are violated. Second, optimization models are proposed to maximize the lifetime of a query-based WSN by selecting the transmission range for all of the sensor nodes, the resource replication level (or time-to-live counter) and the active/sleep schedule of nodes, subject to connectivity and quality-of-service constraints. An improved lower bound is provided for the minimum transmission range needed to ensure no network nodes are isolated with high probability. The optimization models select the optimal operating parameters in each period of a finite planning horizon, and computational results indicate that the maximum lifetime can be significantly extended by adjusting the key operating parameters as sensors fail over time due to energy depletion. Finally, optimization models are proposed to maximize the demand coverage and minimize the costs of locating, and relocating, cluster heads in mobile WSNs. In these models, the locations of mobile sensor nodes evolve randomly so that each sensor must be optimally assigned to a cluster head during each period of a finite planning horizon. Additionally, these models prescribe the optimal times at which to update the sensor locations to improve coverage. Computational experiments illustrate the usefulness of dynamically updating cluster head locations and sensor location information over time

A computational approach to the free radical polymerization of acrylates and methacrylates

In dit doctoraatswerk worden computationele moleculaire modelleringsmethoden aangewend om verschillende aspecten te bestuderen die van belang zijn bij de vrije radicalaire polymerizatieprocessen van acrylaten en methacrylaten. Vrije radicalaire polymerizatie vormt één van de belangrijkste chemische processen die gebruikt wordt in de industrie om een brede waaier van polymeren te produceren. Met dit proces kunnen een grote variëteit van vinyl monomeren omgezet worden naar hoog moleculair moleculair gewicht polymeer materialen, zonder dat een uitgebreide zuivering van commercieel beschikbare monomeren en oplosmiddelen nodig is. Anderzijds kent het proces ook een aantal tekortkomingen zoals de moeilijke beheersing van een aantal eigenschappen die de macromoleculaire structuren kenmerken zoals het moleculair gewicht, de polydispersiteit, eindfunctionaliteit, ketting architectuur, en de samenstelling. Om de eigenschappen van de geproduceerde materialen te optimaliseren is het van primordiaal belang dat een goed inzicht wordt verkregen in de relatie tussen de structuur van het monomeer, het reactiemechanisme en de uiteindelijk verkregen macroscopische eigenschappen. In deze thesis werd een dergelijke studie uitgevoerd voor acrylaten en methacrylaten, waarbij verschillende aspecten worden bekeken, zoals invloed van solvent op tacticiteit, ketenlengte afhankelijkheid van kinetische snelheidsconstanten, … Voor de bestudeerde systemen kunnen de experimenteel bevonden waarnemingen verklaren en aldus vormen computationele technieken een belangrijk hulpmiddel voor deze onderzoeksdiscipline

DOES HIGHER SHARE IN TOTAL TRADE STIMULATE REGIONAL LABOR MARKET OUTCOMES? THE CASE OF TURKEY

Standard trade theory relies on the assumption of long-run full-employment, thus implying that although trade can affect wage rates and change the sectoral distribution of employment, it has no effect on the overall level of employment. In the empirical literature, it is a controversial debate that trade openness is good for employment in the long-run. If so, the further question is about the poorer regions in the developing countries which are fully open to trade. Turkey is one of these countries experienced trade liberalization three decades ago. Although its regions’ connection to markets is effective due to limited lack of access to key inputs and low transport costs, their shares in total trade and labor market outcomes strikingly vary depending on the density of local economic activities. While trade volumes and employment creation capacities of some regions are quite high, relevant indicators for some others are disappointing. The aim of this paper is to explore the relation between regional trade volumes and major labor market indicators. To this end, empirical analyses are designed to test the hypothesis that more regional trade volume leads to more employment opportunities and stimulates the job creation capacities of local labor markets. The data sets used in the analyses are from Turkish Statistical Institute, one being trade statistics by province which consists of export and import volume data for 81 provinces. The other set contains individual-based micro data from Household Labor Force Survey and both of these sets are at NUTS level 2, analyzing Turkey with 26 statistical regions. Time-interval for the analyses is from the year 2004 to 2008. Since the nature of labor market data set is cross-sectional and the dependent variable created is a dummy, the methodology used in the study is based on the probit regression. The preliminary results of the paper shows that higher the trade volumes of regions generally improve the indicators of local labor markets in Turkey.

vaccination in a patient with Behcet's disease

Case report: A 25-year-old man with Behcet's disease was admitted because of weakness of the lower limbs and difficulty in urination. He had received a rabies vaccination 2 months previous because he had been bitten by a dog.Findings: Clinical and laboratory findings supported acute transverse myelitis. A hyperintense lesion and expansion at the level of conus medullaris was detected on spinal magnetic resonance imaging.Conclusion: Although neurologic involvement is one of the main causes of mortality and morbidity in Behcet's disease, the factors that aggravate the involvement of the nervous system are still unclear. Vaccination may have been the factor that had activated autoimmune mechanisms in this case. To our knowledge, involvement of the conus medullaris in Behcet's disease after rabies vaccination has not been reported

Coercive Diplomacy Strategy of the EU

Für die EU - vielleicht der wichtigste Akteur, der für das Verhindern der weiteren Ausbreitung von Massen-zerstörungswaffen eingetreten ist und immer noch eintritt - sind die Verhandlungen mit dem Iran im Zu-sammenhang mit dem iranischen Nuklear-Programm sehr wichtig; vor allem wenn man auf die zukünftigen weltweiten Sicherheitsmaβnamen blickt. Wenn aber die Resultate dieser Verhandlungen genauer betrachtet werden wird deutlich, dass sowohl die Strategien der E3, sowie der späteren EU, nur von geringer Bedeutung geblieben sind. Im Groβen und Ganzen ist es nicht gelungen den Iran dazu zu bewegen, auf die Forderungen der internationalen Gemeinschaft einzugehen. Diese Dissertation versucht das Engagement der EU näher zu diskutieren und geht im Besonderen auf die „Coercive Diplomacy“ des Irans ein, um zu untersuchen inwiefern diese Strategie in der Realpolitik des Irans sichtbar wird. Wichtig in diesem Zusammenhang ist zu erörtern, ob diese Art von Diplomatie Erfolge aufzeigt und welche möglichen negativen Konsequenzen sie mitbringt. Auf dem Gebiet der Analysen und Ausarbei-tungen der „Coercive Diplomacy“ wird in der vorliegenden Arbeit Alexander George’s Theorie als wichtigste Expertenmeinung hinzugezogen.As one main actor seeking for non-proliferation of weapons of mass destruction, the negotiations with Iran on its nuclear programme looms large in the EU’s aspirations for future security matters. However, consider-ing the outcomes of the negotiation process with Iran so far, it is apparent that both the initial E3 and then the EU strategies could not manage to dissuade Iran from its non-compliance with the demands of the inter-national community. This study tries to examine the European Union’s engagement with Iran on its nuclear programme in terms of coercive diplomacy implementations of the EU over Iran. In this regard; the concep-tual framework of the coercive diplomacy theory and the practical employment of the theory into the case are respectively dealt with. Thus, the major aim of this thesis is to answer the questions of, first, to what ex-tend the EU has achieved applying a successful coercive diplomacy strategy over Iran and second, what parts of its strategy have not been meeting the conditions favoring an eventual success. With an eye to dif-ferent depictions and analyzes subscribed by scholars through time, through this study the contributions conducted by Alexander George to the theorization of coercive diplomacy will be taken as the primary meth-odological assessment