• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 339
  • 129
  • 63
  • 34
  • 33
  • 22
  • 15
  • 8
  • 5
  • 4
  • 3
  • 3
  • 3
  • 3
  • 2
  • Tagged with
  • 805
  • 90
  • 88
  • 79
  • 61
  • 52
  • 48
  • 48
  • 46
  • 46
  • 45
  • 44
  • 44
  • 42
  • 42
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
221

FPGA vs. SIMD: Comparison for Main Memory-Based Fast Column Scan

Nusrat, Jahan Lisa, Ungethüm, Annett, Habich, Dirk, Lehner, Wolfgang, Nguyen, Duy Anh Tuan, Kumar, Akash 23 March 2023 (has links)
The ever-increasing growth of data demands reliable data-base system with high-throughput and low-latency. Main memory-based column store database systems are state-of-the-art on this perspective, whereby data (values) in relational tables are organized by columns rather than by rows. In such systems, a full column scan is a fundamental key operation and thus, the optimization of the key operation is very crucial. This leads to have compact storage layout based fast column scan techniques through intra-value parallelism. For this reason, we investigated on different well-known fast column scan techniques using SIMD (Single Instruction Multiple Data) vectorization as well as using Field Programmable Gate Arrays (FPGA). Moreover, we present selective results of our exhaustive evaluation. Based on this evaluation, we find out the best column scan technique as per implementation mechanism–FPGA and SIMD. Finally, we conclude this paper via mentioning some lessons learned for our ongoing research activities.
222

Создание математической модели технологического процесса энергопотребления зданий : магистерская диссертация / Creation of a mathematical model of the technological process of energy consumption of buildings

Берёзкин, И. А., Berezkin, I. A. January 2023 (has links)
Цель работы – создание математической модели технологического процесса энергопотребления здания, создание набора данных, создание нейросети для прогнозирования энергопотребления здания, выявление закономерностей и аномалий. Объект исследования – энергопотребление здания. Рассматриваются различные факторы, такие как работа системы кондиционирования, системы подачи воды, бытовые приборы, освещение помещения. Детально рассмотрена система кондиционирования. Построена математическая модель в итераторе OpenModelica, учитывающая факторы внешней и внутренней среды здания. Собран набор данных в формате .csv. Проведён анализ результатов, выявлены взаимодействия признаков системы, аномалии влияющие на энергопотребление здания. Написана нейросеть прогнозирующая энергопотребление здания, создан pipeline для выявления и визуализации аномалий. Результаты представлены на графиках, сделаны выводы. В ходе полученных результатов были предложены методы оптимизации работы системы, которые привели к экономическому и экологическому эффекту. / The purpose of the work is to create a mathematical model of the technological process of energy consumption of a building, create a data set, create a neural network to predict the energy consumption of a building, identify patterns and anomalies. The object of study is the energy consumption of the building. Various factors are considered, such as the operation of the air conditioning system, water supply system, household appliances, and room lighting. The air conditioning system is examined in detail. A mathematical model was built in the OpenModelica iterator, considering the factors of the external and internal environment of the building. Collected data set in .csv format. An analysis of the results was carried out, interactions of system characteristics and anomalies affecting the energy consumption of the building were identified. A neural network was written to predict the energy consumption of a building, and a pipeline was created to identify and visualize anomalies. The results are presented in graphs and conclusions are drawn. As a result of the results obtained, methods were proposed to optimize the operation of the system, which led to economic and environmental benefits.
223

Investigation of supernumerary centrosomes accumulation and Caspase-2 activation in human cell lines

Dzhilyanova, Iva Georgieva 28 February 2022 (has links)
Centrosomes are microtubule-based organelles composed of two centrioles and peri-centriolar material, involved in the formation and organization of the mitotic spindle, serving as microtubule-organizing center and involved in ciliogenesis. Supernumerary centrosomes are detrimental for cell physiology and activate the PIDDosome, a multi-protein complex that serves as a platform for the activation of Caspase-2, composed of: PIDD1, RAIDD and Caspase-2 itself. Caspase-2’s preferred cleavage site based on peptide screening is VDVAD, however Caspase-2, when activated via the PIDDosome, cleaves its bona fide substrate MDM2 (negative p53 regulator) in the FDVPD sequence. Here, I present evidence for VDVADase activity in apoptotic cells lacking Caspase-2, which suggests that this cleavage site is not Caspase-2 specific when the Caspase-2 activation occurs via the PIDDosome. In order to investigate if the mode of activation of Caspase-2 determines its substrate specificities I performed a Caspase-2 rescue experiment and introduced several mutations affecting the Caspase-2 autoproteolytic-processing. Furthermore, I present evidence that exogenous Caspase-2 is able to form the PIDDosome and cleaves MDM2 but when key autoproteolytic sites are mutated no MDM2 cleavage is detectable. Supernumerary centrosomes also accumulate upon overexpression of PLK4 (a kinase regulator of the centriole duplication). Immunofluorescence images of cells overexpressing PLK4 were taken following the centrioles quantification over time. Consequently, a large amount of image data was accumulated, which necessitated the development of a semi-automated pipeline for centrioles counting. This pipeline was generated using the image processing and analysis tool ImageJ and the deep learning segmentation tool MitoS together with the pretrained MitoSegNet model, which was finetuned to count centrioles stained against different centrosomal epitopes, namely Centrin 1, γ-Tubulin and ANKRD26. This semi-automated method of centrioles quantification is easy to use, reproducible and faster than manual quantification. Using this pipeline to quantify centrioles in p53, SCLT1 or ANKRD26 lacking cells we demonstrate accumulation of supernumerary centrosomes in these cells similar to parental cells. / I centrosomi sono organelli cellulari a base di microtubuli, composti da due centrioli e dal materiale pericentriolare che li circonda. I centrosomi sono coinvolti nell'organizzazione dei microtubuli, nella formazione del fuso mitotico e nella ciliogenesi. I centrosomi soprannumerari sono dannosi per la fisiologia cellulare e attivano il PIDDosoma, un complesso multiproteico, composto da PIDD1, RAIDD e Caspasi-2, che funge da piattaforma per l'attivazione della caspasi stessa. Il sito preferenziale di proteolisi di Caspasi-2 è stato individuato tramite screening peptidico nella sequenza VDVAD. Nonostante ciò, quando attivata tramite il PIDDosoma, Caspasi-2 scinde il suo substrato di elezione MDM2 (regolatore negativo di p53) a livello della sequenza FDVPD. In questa tesi presento evidenze di attività VDVAD-asica in cellule apoptotiche prive di Caspasi-2, suggerendo che questo sito di taglio non sia specifico di Caspasi-2 quando la sua attivazione avviene tramite il PIDDosoma. Al fine di indagare se la modalità di attivazione della proteasi determina le sue specificità di substrato, ho eseguito esperimenti di complementazione di Caspasi-2 facendo uso di diversi mutanti che influenzano il suo processamento autoproteolitico. Inoltre, presento prove che Caspasi-2 esogena è in grado di assemblare il PIDDosoma e proteolizzare MDM2 ma quando i suoi siti chiave di autoproteolisi sono mutati non è rilevabile il taglio di MDM2. I centrosomi soprannumerari si accumulano anche in caso di sovraespressione di PLK4 (chinasi regolatrice della duplicazione dei centrioli). Immagini di immunofluorescenza di cellule che sovraesprimono PLK4 sono state acquisite seguendo la cinetica di accumulo dei centrioli nel tempo. Di conseguenza, l’ingente mole di dati generati ha reso necessario lo sviluppo di una procedura semiautomatica per la conta dei centrioli. Questa pipeline è stata generata utilizzando il programma di elaborazione e analisi di immagini ImageJ e il programma di segmentazione basato su deep learning MitoS, insieme al modello MitoSegNet, che è stato affinato per la conta dei centrioli evidenziati tramite immunofluorescenza diretta contro diversi epitopi centrosomiali, ossia: Centrin 1, γ-Tubulina e ANKRD26. Questo metodo semiautomatico di quantificazione dei centrioli è facile da usare, riproducibile e più veloce della quantificazione manuale. Utilizzando questa procedura per quantificare i centrioli nelle cellule prive di p53, SCLT1 o ANKRD26, dimostriamo che l'accumulo di centrosomi soprannumerari in queste cellule è simile a quello riscontrato nelle cellule parentali.
224

Monitoring sand particle concentration in multiphase flow using acoustic emission technology

El-Alej, Mohamed Essid January 2014 (has links)
Multiphase flow is the simultaneous flow of two or several phases through a system such as a pipe. This common phenomenon can be found in the petroleum and chemical engineering industrial fields. Transport of sand particles in multiphase production has attracted considerable attention given sand production is a common problem especially to the oil and gas industry. The sand production causes loss of pipe wall thickness which can lead to expensive failures and loss of production time. Build-up of sand in the system can result in blockage and further hamper production. Monitoring of multiphase flow is a process that has been established over several decades. This thesis reports an assessment of the application of Acoustic Emission (AE) technology as an alternative online technique to monitoring of sand particles under multiphase flow conditions in a horizontal pipe. The research was conducted on a purpose built test rig with the purpose of establishing a relation between AE activity and sand concentration under different multiphase flow conditions. The investigation consisted of five experimental tests. The initial experiment was performed to provide a basis for the application of AE technology to detect sand particle impact prior to performing tests in multiphase flow conditions. Further investigations are reported on two phase air-sand, water-sand and air- water-sand three-phase flows in a horizontal pipe for different superficial gas velocities (VSG), superficial liquid velocities (VSL) and sand concentrations (SC). The experimental findings clearly showed a correlation exists between AE energy levels and multiphase flow parameters, such as superficial liquid velocity (VSL), superficial gas velocity (VSG), sand concentration and sand minimum transport condition (MTC).
225

Antecedents of Sales Lead Performance: Improving Conversion Yield and Cycle Time in a Business-to-Business Opportunity Pipeline

Bradford, William R 01 May 2016 (has links)
Identifying new potential customers and developing opportunities until converted to sales is a critical function of a sales organization. In most industrial business contexts, opportunities are monitored within a sales pipeline or funnel, to track the status and progress from the initial stage until the sale is completed, often using sales force automation tools, such as customer relationship management (CRM) systems to manage the process. While much is written about the adoption, usage, and failures of CRM, little empirical research exists to fully examine the levers to improve the conversion performance of sales leads, particularly in a business-to-business (B2B) industrial context. The research based view (RBV) of the firm suggests that competitive advantage is gained from a company’s distinct resources, and that in technology and other fast-paced markets, success is further determined by fast adaptation, in what is know as dynamic capability theory. This research examined certain key sales capabilities, within the high technology industrial B2B sector, to understand the impact of sales effort, sales ability and lead source, on sales lead conversion yield and cycle time. By studying the extensive CRM data base of a large semiconductor company, along with various human resource records, a quantitative study was performed to address this research, while providing useful value to sales managers seeking to improve the lead conversion performance of their organizations. Sales effort, as measured by number of sales calls made per week, and percent of time spent on selling activities was shown to modestly accelerate sales cycle times, but have no effect on the percentage of opportunities that result in wins. Sales ability, measured by annual performance ratings, prior year quota attainment and years of experience showed no effect on cycle time, nor win percentage. The most notable contribution of this research is the illumination of sales effort effects on cycle time, as previous studies of sales cycle time influences have been inconclusive. Against the backdrop of a general lengthening of industrial sales cycle times, understanding that salesperson effort can reduce the time that it takes to win an opportunity can drive meaningful improvements in salesforce efficiency and productivity.
226

Falling through the cracks : community based programs fill in the gaps that school discipline leaves behind

Asase, Dagny Adjoa 06 October 2014 (has links)
The purpose of this report is to focus on the school-to-prison pipeline and the need to intervene with school discipline that pushes students out of the classroom and into the criminal justice system. It showcases services and programs in Austin, Texas, including Southwest Keys, Webb Youth Court, and Council on At-Risk Youth as examples for solutions. The report also incorporates research and expert advice on the safety and wellbeing of students while advocating a need to change the policies and culture surrounding schools. / text
227

An assessment of entrepreneurial orientation at a pipeline gas company / Hendrick Lehlogonolo Mokgoto

Mokgoto, Hendrick Lehlogonolo January 2013 (has links)
The general aim of the study was to determine the influence of entrepreneurial orientation on the perceived success of the pipeline gas company. This type of study has not been conducted previously for such a pipeline gas company and as such, a valuable contribution could be made to a more effective entrepreneurial orientation in the business environment. Two questionnaires were administered, which focused on entrepreneurial orientation and perceived success of business respectively. A response rate of 87.63% was obtained from a sample of 97 employees at management level in the pipeline gas company concerned. The results showed a statistically significant positive relationship between entrepreneurial orientation and business development as variable of business success. The data also revealed correlations among the dimensions of entrepreneurial orientation, some with significant differences for various demographic groups and their level of entrepreneurial skills. Limitations within the study were discussed and recommendations were made for future research. / MBA, North-West University, Potchefstroom Campus, 2014
228

Structural integrity of carbon dioxide transportation infrastructures

Zargarzadeh, Payam January 2013 (has links)
Carbon Capture and Storage (CCS) is recognised as having a significant role to play in tackling climate change and reducing carbon dioxide (CO2) emissions. In CCS schemes, CO2 is captured from anthropogenic sources, and transported to suitable sites either for EOR (Enhanced Oil Recovery) or storage. The transport of such huge amount of CO2 causes new challenges. The main concern is in the difference between natural gas and CO2 transportation pipelines. CO2 phase behaviour during decompression, existence of different impurities and very high operating pressure are some of the new challenges for pipeline designer and operators. This PhD study has taken a systematic approach to understand the mechanics involved in the fracture of pipes containing high pressure flue-gas CO2. The work involved the development of a novel weight function stress intensity factor solution that can be used with complex stress fields induced by residual and/or thermal stresses in addition to applied pressure. In addition, the thesis reports a substantial experimented test programme which involved low temperature fracture toughness tests linked to a detailed finite element based stress analysis. Overall, the thesis presents an integrated engineering criticality means to assess the suitability or otherwise of a pipeline system to transport high pressure flue-gas CO2.
229

Flexible liners for corrosion protection of pipelines

Allison, Crispin January 2012 (has links)
Flexible plastic liners are sometimes installed into new and existing oil and gas pipelines to prevent corrosion of the pipe wall. A practical difficulty of this method is that the plastic liners are permeable to gases, which can collect and form an annular space between the liner and the pipe. If the operating pressure in the pipe decreases then the collected gas can cause the liner to collapse and block the pipe. One method for overcoming this problem is to insert vents at intervals along the liner to allow the gas to escape into the pipe during depressurisation. However, there is concern that this arrangement might lead to excessive corrosion beneath the vent where the pipe wall is exposed. The rate of corrosion is expected to be controlled by the vent size but this principle needs to be confirmed by experiment. The work described in this thesis is aimed at investigating this corrosion by experiment for a range of conditions typical of oil and gas production. A novel crevice corrosion cell was designed, consisting of an X100 carbon steel plate and a sheet of transparent Perspex, separated by a thin gasket. A small hole in the Perspex simulated a liner vent and allowed carbon dioxide to reach the steel surface. Tests were carried out in 3.5% NaCl solutions saturated with carbon dioxide at 1 bar partial pressure. Corrosion rates along the length of the annular space were measured using the Linear Polarisation Resistance (LPR) technique on pairs of insulated X100 electrodes set into the plate. The corrosion rates within the annular space have been shown to be small compared to those in the bulk solution and to diminish rapidly with distance from the vent. Mathematical modelling, based on the transport of carbon dioxide, is described to explain these findings and support the experimental work. The effectiveness of the LinerVentTM, installed over the vent, in a turbulence pipeline was demonstrated. The benefit of applying cathodic protection within the annular space was also demonstrated. The results are discussed in terms of the fundamental corrosion principles and their practical implications
230

Assessment of Ephemeral Channel Cross-Section Morphology Following Pipeline Construction in Southern Arizona

Miller, Hennessy Felicia, Miller, Hennessy Felicia January 2017 (has links)
Morphologic change of ephemeral stream cross-sections is a natural component of fluvial geomorphology but disruptions to natural erosion and deposition by anthropogenic disturbances has the potential for cascading impacts down the channel corridor. The proximal impact of a natural gas pipeline construction on ephemeral stream cross-section geometry in southern Arizona was evaluated from July 2014 (pre-construction) to July 2016 (two years post construction). Cross-sections at three locations (upstream the pipeline Right-Of-Way (ROW)), through the middle of the ROW, and downstream of the ROW) were measured using Light Detection And Ranging (LIDAR) and field methods for 16 ephemeral streams. Results of both the LIDAR and field measurements indicated insignificant difference in cross-sectional area change between upstream, across, and downstream-ROW cross-sections [(F 2,64) = 0.341, p = 0.73; (F2,18)= 0.980, p = 0.395]. Sediment generated during pipeline construction appeared to have moved beyond the physical confines of the study site, which limited the assessment of larger-scale geomorphic impacts. Furthermore, the 2014-2016 study period experienced only small (high-recurrence frequency) precipitation events, indicating the absence of large flows capable of significant morphologic change. To further explain differences in cross-section area change between LIDAR datasets, a linear regression model was used to assess the predictive value of nine variables: year of measurement, drainage area, drainage density, basin slope, upstream-, across-, downstream-ROW cross-section locations, percent bare soil in basin, percent mesquite in basin, total precipitation, and number of storms with average precipitation above 25 mm/hour. Though the amount of bare soil in the basin and the second study period (February 2015-July 2016) at least partially explained the changes in cross-section area, the model was not a strong predictor of morphologic change during the 2014-2016 study period. The majority of the variability in cross-sectional area change in the study basins remained unexplained.

Page generated in 0.0697 seconds