Processing Posting Lists Using OpenCL

One of the main requirements of internet search engines is the ability to retrieve relevant results with faster response times. Yioop is an open source search engine designed and developed in PHP by Dr. Chris Pollett. The goal of this project is to explore the possibilities of enhancing the performance of Yioop by substituting resource-intensive existing PHP functions with C based native PHP extensions and the parallel data processing technology OpenCL. OpenCL leverages the Graphical Processing Unit (GPU) of a computer system for performance improvements. Some of the critical functions in search engines are resource-intensive in terms of processing power, memory, and I/O usage. The processing times vary based on the complexity and magnitude of data involved. This project involves different phases such as identifying critical resource intensive functions, initially replacing such methods with PHP Extensions, and eventually experimenting with OpenCL code. We also ran performance tests to measure the reduction in processing times. From our results, we concluded that PHP Extensions and OpenCL processing resulted in performance improvements

Real-time comparisons of ionospheric data with outputs from the UAF eulerian parallel polar ionosphere model

Thesis (M.S.) University of Alaska Fairbanks, 2007The UAF theoretical polar ionospheric model (UAF EPPIM) solves 3D equations of mass, momentum, and energy balance for multiple ion species to determine ion and electron parameters in the polar ionosphere region using a parallel numerical code on an Eulerian grid. Real time operation of the model is very important because users are interested in current space weather conditions. Real-time validation of this model with available experimental data is an important task for the following reasons. (1) Real-time validation can provide much information about the model quality and define the directions of improvement. (2) Real-time comparisons help to determine trusted intervals for the model parameters for future data assimilation tasks. In this work, we have developed an operational real-time comparisons capability which assimilates HAARP (High frequency Active Auroral Research Program) experimental data for the model validation purposes. Software has been developed to emulate Total Electron Content (TEC). Results are then compared with real-time data from HAARP. Further, we have developed a Computerized Ionospheric Tomography (ClT) model which provides ionosphere tomography images covering five different stations in Alaska along the geomagnetic latitude (50-78 degrees). Then these images are compared with real-time ionosphere tomography images obtained at the HAARP website.1. Introduction -- 2. Coordinate systems overview -- 3. The ionosphere and its monitoring -- 4. GPS total electron content comparisons -- 5. Ionospheric tomography -- 6. Software development -- 7. Summary, conclusions, and future work -- References -- Appendix: NOAA format data file

FINDING BURST CONTENT IN ONLINE STREAM VIA URL BASED DETECTION

Detection of emerging topics is now receiving renewed interest motivated by the rapid growth of social networks. Conventional-term-frequency-based approaches may not be appropriate in this context, because the information exchanged in social-network posts include not only text but also images, URLs, and videos. We focus on emergence of topics signaled by social aspects of theses networks. Specifically, we focus on mentions of user links between users that are generated dynamically (intentionally or unintentionally) through replies, mentions, and retweets. We propose a probability model of the mentioning behavior of a social network user, and propose to detect the emergence of a new topic from the anomalies measured through the model. Aggregating anomaly scores from hundreds of users, we show that we can detect emerging topics only based on the reply/mention relationships in social-network posts. We demonstrate our technique in several real data sets we gathered from Twitter. The experiments show that the proposed mention-anomaly-based approaches can detect new topics at least as early as text-anomaly-based approaches, and in some cases much earlier when the topic is poorly identified by the textual contents in posts

The Values of Craft : the Indian case

How do we understand the role and significance of Intangible cultural heritage in our lives? What role does it play in the process of production of and consumption of crafts? What lenses are most appropriate as means of making sense of the economics of crafts? The thesis investigates these questions with a focus on the crafts in India. It begins with a look through the lenses of standard economics and continues with a culturalists perspective. It then applies the so-called value-based approach to resolve some paradoxes that emerge during the course of the study. The thesis concludes with recommendations for economists, craftspeople and policymakers based on a utopian perspective on the crafts in India

Surface passivation effects of aluminium oxide on ultra-thin CIGS solar cells

Among all thin-film (TF) technologies, photovoltaic (PV) cells based on copper indium gallium diselenide (CIGS) absorbers yield the highest efficiency (>22%). Current approaches and future priorities within the CIGS TF PV community are focused on CIGS thickness reduction to further lower material costs and surface passivation concepts to reduce the electronic recombination at interfaces and further enhance the solar cell performance. These approaches involve novel methods to passivate the front and rear surfaces of the CIGS absorber by implementing (i) alkali post-deposition treatments at the front surface and (ii) rear surface field-effect passivation using gallium grading schemes within the CIGS absorber layer. However, above-mentioned surface passivation approaches have been shown less effective when considering ultra-thin ( 2µm). Additionally, in-depth analyses on the materials and devices were carried out using advanced opto-electrical and material characterization techniques to understand, correlate and optimize these properties towards stable, efficient solar cells. Lastly, to generalize these electronic and interface passivation effects on the CIGS solar cell performance, for the first time, a simulation model has been developed using SCAPS TF PV software.(FSA - Sciences de l'ingénieur) -- UCL, 201

Asynchronous Advanced Encryption Standard Hardware with Random Noise Injection for Improved Side-Channel Attack Resistance

This work presents the design, hardware implementation, and performance analysis of novel asynchronous AES (advanced encryption standard) Key Expander and Round Function, which offer increased side-channel attack (SCA) resistance. These designs are based on a delay-insensitive (DI) logic paradigm known as null convention logic (NCL), which supports useful properties for resisting SCAs including dual-rail encoding, clock-free operation, and monotonic transitions. Potential benefits include reduced and more uniform switching activities and reduced signal-to-noise (SNR) ratio. A novel method to further augment NCL AES hardware with random voltage scaling technique is also presented for additional security. Thereby, the proposed components leak significantly less side-channel information than conventional clocked approaches. To quantitatively verify such improvements, functional verification and WASSO (weighted average simultaneous switching output) analysis have been carried out on both conventional synchronous approach and the proposed NCL based approach using Mentor Graphics ModelSim and Xilinx simulation tools. Hardware implementation has been carried out on both designs exploiting a specified side-channel attack standard evaluation FPGA board, called SASEBO-GII, and the corresponding power waveforms for both designs have been collected. Along with the results of software simulations, we have analyzed the collected waveforms to validate the claims related to benefits of the proposed cryptohardware design approach

Surface passivation effects of aluminium oxide on ultra-thin CIGS solar cells

Among all thin-film (TF) technologies, photovoltaic (PV) cells based on copper indium gallium diselenide (CIGS) absorbers yield the highest efficiency (>22%). Current approaches and future priorities within the CIGS TF PV community are focused on CIGS thickness reduction to further lower material costs and surface passivation concepts to reduce the electronic recombination at interfaces and further enhance the solar cell performance. These approaches involve novel methods to passivate the front and rear surfaces of the CIGS absorber by implementing (i) alkali post-deposition treatments at the front surface and (ii) rear surface field-effect passivation using gallium grading schemes within the CIGS absorber layer. However, above-mentioned surface passivation approaches have been shown less effective when considering ultra-thin ( 2µm). Additionally, in-depth analyses on the materials and devices were carried out using advanced opto-electrical and material characterization techniques to understand, correlate and optimize these properties towards stable, efficient solar cells. Lastly, to generalize these electronic and interface passivation effects on the CIGS solar cell performance, for the first time, a simulation model has been developed using SCAPS TF PV software.(FSA - Sciences de l'ingénieur) -- UCL, 201

Post COVID-19 multisystem inflammatory syndrome in adults: a new clinical challenge

The spectrum of novel coronavirus disease (COVID-19) continues to evolve since its outbreak in November 2019. Although COVID-19 most commonly causes substantial respiratory pathology, it can also result in several extra pulmonary manifestations. Association between COVID-19 disease and a multisystem inflammatory syndrome in children (MIS-C) and adolescents has now been well defined. However, case reports describing a similar phenomenon in adults are sparse. We presented a case of 42 year old male who presented 3 weeks after initial COVID-19 infection with acute ST elevation myocardial infarction, splenic artery thrombosis, generalized anasarca, with hepatic and renal dysfunction, but minimal respiratory symptoms. He had a turbulent hospital course. However timely suspicion of presence of multisystem inflammatory syndrome in adult (MIS-A) and use of hemoadsorption filters helped to save his life

Passivation of interfaces in thin film solar cells: understanding the effects of a nanostructured rear point contact layer

Thin film solar cells based in Cu(In,Ga)Se2 (CIGS) are among the most efficient polycrystalline solar cells, surpassing CdTe and even polycrystalline silicon solar cells. For further developments, the CIGS technology has to start incorporating different solar cell architectures and strategies that allow for very low interface recombination. In this work, we study and characterize ultrathin 350 nm CIGS solar cells with a rear interface passivation strategy. The rear passivation was achieved using an Al2O3 nanopatterned point structure. Using the cell results, photoluminescence measurements and detailed optical simulations based on the experimental results, we show that by including the nanopatterned point contact structure, the interface defect concentration lowers, which ultimately leads to an increase of solar cell electrical performance mostly by increase of the open circuit voltage. Gains to the short circuit current are distributed between an increased rear optical reflection and also due to electrical effects. Our approach of mixing several techniques allowed us to make a discussion considering the different passivation gains which has not been done in detail in previous works. A solar cell with a nanopatterned rear contact and a 350 nm thick CIGS absorber provided an average power conversion efficiency close to 10%.publishe

Porous ferroelectrics for energy harvesting applications

This paper provides an overview of energy harvesting using ferroelectric materials, with a particular focus on the energy harvesting capabilities of porous ferroelectric ceramics for both piezo- and pyroelectric harvesting. The benefits of introducing porosity into ferro- electrics such as lead zirconate titanate (PZT) has been known for over 30 years, but the potential advantages for energy harvesting from both ambient vibrations and temperature fluctuations have not been studied in depth. The article briefly discusses piezoelectric and pyro- electric energy harvesting, before evaluating the potential benefits of porous materials for increasing energy harvesting figures of merits and electromechanical/electrothermal coupling factors. Established processing routes are evaluated in terms of the final porous structure and the resulting effects on the electrical, thermal and mechanical properties