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Flamigni, Bianca. "Supporto all'Analisi Statistica basata su R in Ambiente Apache Spark." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2017.
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Le ultime tendenze nell’analisi di Big Data indicano il sempre più crescente bisogno di poter effettuare analisi interattiva su questi grandi dataset. Tipicamente si utilizza il linguaggio R per fare analisi avanzata sui dati, ma, a causa di limitazioni di livello tecnico, questo non è in grado di gestire Big Data in modo efficiente. Per tale motivo è stato ideato SparkR, un progetto, basato su Spark, per l’esecuzione distribuita di programmi in R scalabili e adatti a diversi tipi di carichi di lavoro. In questo documento, analizzeremo approfonditamente il progetto SparkR e ne osserveremo le prestazioni, a fronte di diverse applicazioni tipiche dell’analisi di Big Data (algoritmi di clustering e query interattive), in modo da poter identificare possibili limiti o colli di bottiglia e, grazie alla conoscenza acquisita, proporremo delle soluzioni in grado di ottenere buoni miglioramenti prestazionali. Tra queste, un componente che, sfruttando lo storico delle applicazioni lanciate, è capace di configurare in automatico alcune proprietà interne a Spark ed ottenere di conseguenza una riduzione nei tempi di esecuzione degli applicativi in R. Forniremo i risultati che dimostrano come grazie alla nostra proposta sia possibile ottenere un miglioramento del 18% rispetto alla configurazione di default di Spark. Infine, proporremo l’implementazione di un supporto efficiente e ben scalabile ad un algoritmo di clustering gerarchico, Bisecting K-means, e dimostreremo, tramite un’attenta valutazione delle prestazioni, come rappresenti un buon compromesso per garantire l’utilizzo di una tecnica così diffusa, come quella del clustering gerarchico, in un ambiente distribuito, nonostante algoritmi di questo genere siano noti per non essere particolarmente compatibili con un modello di programmazione tale.
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Cox-Richard, Lillian. "Spark Gap." VCU Scholars Compass, 2008. http://scholarscompass.vcu.edu/etd/698.
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"Spark Gap" is an invisible electrical force made visible in spaces between things. This usually describes the space of air between two conductors; a non-conductive gap in an otherwise complete electric circuit, across which a quick luminous disruptive electrical discharge occurs. This interstitial space is the distance between two ideas, arced with a running leap. The arc can also be the difference between two things, a gap that becomes apparent only when the two are held in close proximity. In my thesis exhibition, "Spark Gap," a sea urchin shaped orb sits atop a tower of ladders. The orb is broken into five sections and reassembled, each fault line occurring along the perfect zigzag line of its cellular structure. On the floor, there is a linen shag rug, marked as if struck by lightning. This exhibition is named for an interstitial charge, arcing across distance or difference. But this charge is also found in intersections and similarities. Imagine the friction created by rubbing together the circles of a Venn diagram: the overlapping section would begin to spark. It is in these gaps and overlaps that I find the impetus for my work.
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Samandari, Farshid. "Sparks of Union." Thesis, University of British Columbia, 2014. http://hdl.handle.net/2429/46483.
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This document delves into the precept of unity in diversity from a musical perspective, in order to replace the timeworn aesthetic norms with ones that may induce a music befitting the fabric of our contemporary global village. It deals with the contemporary musical zeitgeist from this perspective and examines the transformations in musical substance derived from the copious changes in dissemination since the information revolution. It also presents Sparks of Union, a 20-minute composition for ten Western instruments and interactive electronics. This composition aims to focus on different musical languages in search of polarizing and uniting elements, and explores free interactions between the different musical elements. As a result it strives to create new sonorities derived from a fully democratic multicultural interaction.
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Hwang, Suk Hyun. "Optimization of the Photovoltaic Time-series Analysis Process Through Hybrid Distributed Computing." Case Western Reserve University School of Graduate Studies / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=case1587128073434884.
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Kim, Kwanghoon. "Infrared luminescence from spark-processed silicon and erbium-doped spark-processed silicon." [Gainesville, Fla.] : University of Florida, 2005. http://purl.fcla.edu/fcla/etd/UFE0012860.
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Mahajan, Rohan. "Adaptive scheduling in Spark." Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/105977.
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Thesis: M. Eng., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2016.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (page 33).
Because most data processing systems are distributed in nature, data must be transferred between machines. Currently, Spark, a prominent such system, predetermines the strategies for shuffling this data, but in certain situations, different shuffle strategies would improve performance. We add functionality to track metrics about the data during the job and appropriately adapt the shuffle strategy. We show improvements in ShuffledRDD performance, joins using Spark's RDD interface, and joins in Spark SQL.
by Rohan Mahajan.
M. Eng.
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Walls, Kate. "Muriel Spark and Catholicism." Thesis, Queen's University Belfast, 2014. https://pure.qub.ac.uk/portal/en/theses/muriel-spark-and-catholicism(2d16b200-588b-4866-a1d6-dea6396b68cb).html.
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My PhD thesis analyses Catholic themes in the novel,s of Scottish born writer Muriel Spark. Spark's career spanned five decades, and much of her work was influenced by her conversion to Catholicism. She is a sophisticated and enigmatic writer whose work defies categorisation. Part of this difficulty stems from her position as "other" within Catholicism· -a result of her conversion and her refusal to adhere to traditional Catholic gender roles. What does become clear upon examining Spark's fiction is that she uses subversive and paradoxical rhetoric to highlight the problems inherent in being unable to fully comprehend God's mystery. Spark appears to be obsessed with several religious concepts that appear constantly in her fiction. In the case of the Catholic convert and the Book of Job, these threads appear repeatedly and build to a climax-once Spark comprehensively addresses them in her fiction, the threads disappears from her work entirely. In exploring these Catholic themes, it becomes clear that, despite Spark's work being abundant with references to religion, there is very little narrative space devoted to the character's internal thoughts regarding God and religious thought. I argue that in Spark's fiction, creativity is a proxy for religious faith. Spark draws parallels to the personal and individual nature of both, but devotes more narrative space to explaining a sense of faith in the creative process. She also appears to grant narrative endorsement to characters who believe in and ate guided by their creativity, even when they clearly traverse the boundaries of acceptable "moral" behaviour.
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Kim, Jaecheol. "The role of radicals supplied directly and indirectly on ignition." Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/53001.
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The ignition process is a critical consideration for combustion devices. External energy transfer to the combustor is required for ignition in common combustion systems. There are many ways to deposit energy into the flow but a standard method is a spark discharge because it is simple, compact, and reliable. Sparks can be categorized as either inductive or capacitive sparks that use a coil or an electrical resonance circuit with capacitor, respectively, to amplify the voltage. The creation of a successful ignition event depends on the spark energy deposited into the flow, the initial composition, pressure, temperature, turbulence level of flow etc. The deposited energy by the spark into the flow is critical for estimation of initial energy available for ignition of the mixture. Therefore, the electrical characteristics of the sparks were investigated under various flow conditions. Then measurements of deposited energy into the flow were conducted using a very accurate experimental procedure that was developed in this research. The results showed considerable electric energy losses to the electrodes for the relatively long, inductive sparks. However, the short, capacitive spark deposits electric energy into the flow with minimal loss (above 90% deposition efficiency). In addition, the characteristics of inductive spark are affected by flow velocity and by the existence of a flame. However, variations in the flow conditions do not affect the characteristics of the capacitive spark such as voltage-current time trace and energy deposition efficiency.
Two ignition systems using above mentioned two spark types were developed. First, the capacitive spark energy was directly deposited into the premixed flow. Most researchers have not concentrated on the early initiation process but on the flame growth. Therefore, the generated kernel formed by the energy deposition was observed and characterized using optical methods, immediately following the spark. In addition, the mixing effect for this ignition kernel with surrounding gas was simulated using a numerical method. Based on the time trace of the OH* chemiluminescence, the reaction starts with the discharge and it is continuous until combustion begins. This means that in the presence of a high density spark in premixed flow, there exists no traditional delay as defined by other researchers for auto ignition.
A simple Radical Jet Generator (RJG) was developed that is able to ignite and stabilize a flame in a high-speed flow. The inductive spark initiates the combustion in the RJG chamber. The RJG then injects the partially-burned products carrying large amounts of heat and radicals into a rapidly moving flammable main stream. Then it ignites and stabilizes a flame. The RJG requires low levels of electrical power as long as the flow velocity is relatively low since most of the radicals are produced by the incomplete combustion in its chamber. The importance of radicals was analyzed by RJG experiments and numerical methods. The reaction zone for RJG using a rich mixture was located both inside and outside of the RJG chamber. Therefore, the RJG using a rich mixture performed better in the ignition and stabilization of combustion in the main flow. According to an analysis using the CHEMKIM simulation software combined with the San Diego chemical mechanism, the RJG jet resulting from a rich mixture contains more radicals and intermediates than that produced by a lean mixture for the same sensible enthalpy. In addition, the burned gas contains less radicals and intermediates than the partially burned gas.
If the RJG is operating with a high speed main flow, the flow rate through the RJG chamber must be increased to allow the radical jet to penetrate well into the rapid flow due to their higher injection velocity. Unfortunately, this leads to unsteady combustion in the RJG, which results in the pulsation of the radical jet. This reduces the number of radicals injected into the main flow. To investigate this operating condition, special attention was focused on four possible factors: unburned reactant pockets caused by motion of the spark channel, spark frequency, flame propagation speed and ignition delay. It was shown that the unsteadiness is affected by the flame speed and ignition delay because the frequency of pulsation in the chamber is highly dependent on the equivalence ratio. In addition, the interaction between the RJG operation and the combustion dynamics in the main combustor was documented. The acoustic pressure oscillations in the main combustor were suppressed when the RJG jet was turned on because the reaction region is relocated by the operation of the RJG.
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Mattsson, Niklas, and Jonas Brorsson. "Kommer företagen att sparka ut revisorn?" Thesis, Umeå University, Umeå School of Business, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-1774.
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Sverige har sedan 1983 haft lagstadgad revisionsplikt för alla aktiebolag. Med anledning av regeringens mål att reducera de administrativa kostnaderna för de svenska företagen tillsattes en utredning om hur revisionsplikten ska avskaffas för de svenska aktiebolagen. Enligt regeringens förslag som presenterades i mars 2008 föreslås en avskaffad revisionsplikt för 96 % av de svenska aktiebolagen.
Avskaffad revisionsplikt innebär en förändring som berör hela näringslivet. Konsekvenserna av avskaffandet är framförallt av intresse för revisionsbranschen och samhället.
Efterfrågan av revision förklaras huvudsakligen genom agentteorin om att det sker en separation mellan ägande och företagsledning. Tidigare studier visar även att faktorer som exempelvis krav från kreditgivare, val av revisionsbyrå och förbättrad kvalité på redovisningen påverkar valet av revision.
Vi har utifrån ett deduktivt angreppssätt genomfört en enkätstudie bland företag i Umeå med 1-49 anställda. Tack vare ekonomiskt stöd från en revisionsbyrå postades enkäten ut till 300 företag fördelade på tre olika urvalskategorier (1-3, 4-9 och 10-49 anställda) och vi erhöll svar från 118 st företag. Syftet med studien vara att få en uppfattning om företagens val av revisions utifrån antagandet om att revisionsplikten är avskaffad samt att förklara de faktorer som har betydelse för företagens val av revision.
Resultaten av studien visar att 54,2 % av företagen i Umeå kommer att fortsätta med revision förutsatt att plikten är avskaffad. Fördelat på de tre olika urvalskategorierna ökar benägenheten att välja revision med storleken. Av företag med 1-3 anställda kommer 45,2 % välja revision, av företag med 4-9 anställda kommer 62,9 % välja revision och av företag med 10-49 kommer 87,8 % att välja revision.
De faktorer som förklarar Umeå-företagens val är företagets storlek, skuldsättningsgrad och upplevd förbättrad internkontroll som alla visat positiva signifikanta samband med valet av revision. Även uppfattad kvalité på redovisning och ökad tillförlitlighet gentemot intressenterna är faktorer som är viktiga i valet av revision.
Vi anser att generaliserbarheten från studien är god eftersom vi erhållit en representativ fördelning av svar från alla kategorier samt att vi viktat svaren efter hur hela populationen ser ut. Detta för att få ett rättvisande resultat på i vilken utsträckning företagen kommer fortsätta med revision.
Resultaten skall dock sättas i perspektivet av att de bygger på att hypotetiskt val och inte företagens faktiska val. Detta innebär vissa implikationer och det är rimligt att anta att det faktiska utfallet kan förändras eftersom vissa faktorer aktualiseras först när plikten är avskaffad, exempelvis krav från kreditgivare för att erhålla lån.
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Eketorp, Erik, and Jonas Finnman. "Hemautomation - Sparar man så kostar det!" Thesis, KTH, Skolan för elektro- och systemteknik (EES), 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-199259.
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Milicic, Drazen, and Pontus Svensson. "Sparks to a living quality organization." Thesis, Blekinge Tekniska Högskola, Institutionen för programvaruteknik och datavetenskap, 1998. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-2731.
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Ni, Ze. "Comparative Evaluation of Spark andStratosphere." Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-118226.
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Nowadays, although MapReduce is applied to the parallel processing on big data, it has some limitations: for instance, lack of generic but efficient and richly functional primitive parallel methods, incapability of entering multiple input parameters on the entry of parallel methods, and inefficiency in the way of handling iterative algorithms. Spark and Stratosphere are developed to deal with (partly) the shortcoming of MapReduce. The goal of this thesis is to evaluate Spark and Stratosphere both from the point of view of theoretical programming model and practical execution on specified application algorithms. In the introductory section of comparative programming models, we mainly explore and compare the features of Spark and Stratosphere that overcome the limitation of MapReduce. After the comparison in theoretical programming model, we further evaluate their practical performance by running three different classes of applications and assessing usage of computing resources and execution time. It is concluded that Spark has promising features for iterative algorithms in theory but it may not achieve the expected performance improvement to run iterative applications if the amount of memory used for cached operations is close to the actual available memory in the cluster environment. In that case, the reason for the poor results in performance is because larger amount of memory participates in the caching operation and in turn, only a small amount memory is available for computing operations of actual algorithms. Stratosphere shows favorable characteristics as a general parallel computing framework, but it has no support for iterative algorithms and spends more computing resources than Spark for the same amount of work. In another aspect, applications based on Stratosphere can achieve benefits by manually setting compiler hints when developing the code, whereas Spark has no corresponding functionality.
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Bútora, Matúš. "Modelem řízený vývoj Spark úloh." Master's thesis, Vysoké učení technické v Brně. Fakulta informačních technologií, 2019. http://www.nusl.cz/ntk/nusl-403168.
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The aim of the master thesis is to describe Apache Spark framework , its structure and the way how Spark works . Next goal is to present topic of Model- Driven Development and Model-Drive Architecture . Define their advantages , disadvantages and way of usage . However , the main part of this text is devoted to design a model for creating tasks in Apache Spark framework . Text desribes application , that allows user to create graph based on proposed modeling language . Final application allows user to generate source code from created model.
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Lodi, Faisal Samad. "Reducing cold start fuel consumption through improved thermal management." Connect to thesis, 2008. http://repository.unimelb.edu.au/10187/3601.
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The thesis presents research in achieving faster warm-up of an SI engine, thereby affecting the fuel economy penalty. The faster warm-up relates to faster heating of the cylinder head and engine block, targeting reducing viscous friction in the cold oil as the most likely candidate to improve. The strategy applied was to reduce the coolant flow circulation rate to achieve a faster warm-up of the engine. A lumped parameter model for engine heat transfer, coolant flow and heat capacities, in a single cylinder, based on engine operating points like spark advance, engine speed and MAP was built in Modelica.The engine used for experimentation was a Ford in-line, 4 stroke, 6-cylinder engine, with a compression ratio of 10.3:1, in which 56 K-type thermocouples were installed at different locations to measure the temperature. The experiments were performed with varying coolant flow rate from normal down to zero, utilizing an electric water pump, over an approximation to the New European Drive Cycle (NEDC), at a speed of 1161 rev/min and load of 48 Nm. The selected speed and load were the average operating condition for 180 seconds of engine running over the urban part of a simulated NEDC. In addition, the coolant circuit was modified to a split cooling supply and the sets of results analyzed to find the reduction in engine warm-up time and fuel consumption.
It is shown from the results that the warm-up time of the engine and the fuel consumption were notably reduced, as the flow was reduced from maximum to minimum in steps. On average over an interval of engine running for 300 seconds from cold start, the cylinder head temperature was increased by about 2°C , the average engine block temperature was increased by about 6.5°C and the average cylinder head coolant temperature was increased by about 4°C . However, the bulk temperature of the oil in the oil sump showed marginal improvement and remained consistent, even at the lowest coolant flow rate. Nonetheless, the improvements in block temperature had significant effects on reducing the friction between the piston and cylinder walls.
Analysis of the results show that the coolant flow pattern changed with the use of an electric water pump. The flow is less evenly distributed around the cylinders with the use of an electric water pump, whilst retaining the mechanical water pump body, compared to the mechanical water pump operation.
The model was applied to simulate for two engine operating points, i.e., 1161 rev/min, 48 Nm load and 700 rev/min and 0 Nm load. The model was calibrated at 1161 rev/min, 48 Nm load and validated at 700 rev/min, 0 Nm load. The modeling results were in fair agreement with the experimental results. The model can be employed to investigate electric water pump control.
The important finding is that around 3% fuel consumption savings are possible over the NEDC by management strategies that lead to faster cylinder block warm up, even though this may result in little or no change in oil temperature as measured in the sump.
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Schäfer, Lukas [Verfasser]. "Modeling and Simulation of Spark Ignition in Turbocharged Direct Injection Spark Ignition Engines / Lukas Schäfer." München : Verlag Dr. Hut, 2016. http://d-nb.info/1106593502/34.
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Kaul, Brian Christopher. "Addressing nonlinear combustion instabilities in highly dilute spark ignition engine operation." Diss., Rolla, Mo. : Missouri University of Science and Technology, 2008. http://scholarsmine.mst.edu/thesis/pdf/Kaul_09007dcc804ea67e.pdf.
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Thesis (Ph. D.)--Missouri University of Science and Technology, 2008.Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed April 28, 2008) Includes bibliographical references (p. 170-176).
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Kapil, Anil. "Cycle-to-cycle variations in spark-ignition engines." Thesis, University of British Columbia, 1988. http://hdl.handle.net/2429/28392.
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Pressure data measurements have been made in a single-cylinder, spark-ignition engine over 100 consecutive cycles. The engine was operated on natural gas at a wide range of engine speed and equivalence ratios. The effects of spark electrode geometry, combustion chamber geometry, spark gap and throttling have also been examined. From these pressure measurements standard deviations in burning times in mass-fraction-burned values were determined. Because of the existing evidence that the origin of cyclic variations is in the early combustion period, the standard deviations of cyclic variation in time required for a small (almost zero) mass-fraction-burned is estimated by extrapolation. These extrapolated values of standard deviation are compared with the implication of a hypothesis that cyclic variations in combustion in spark-ignition engines originate in the small-scale structure of turbulence (after ignition).
The nature of turbulence structure during combustion is deduced
from existing knowledge of mixture motion within the combustion chamber
of the engine. This research determines the turbulent parameters, such
as turbulence intensity, turbulent length scales and laminar burning
velocity. The standard deviation in burning times in the early stages
of combustion is estimated, within experimental uncertainty, by the
parameter ⋋/4uℓ where ⋋ is the Taylor microscale and uℓ is the laminar
burning velocity of the unburned mixture. This parameter is the
consequence of the Tennekes model of small-scale structure of
turbulence and Chomiak's explanation of the high flame propagation
rate in regions of concentrated vorticity and the assumption that theignition behaves as though it were from a point source.
The general conclusion reached is that the standard deviation in the burning time for small mass-fraction-burned is associated with the early stages of burning-predictable from the knowledge of the Taylor microscale and the laminar burning velocity.Applied Science, Faculty of
Mechanical Engineering, Department of
Graduate
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Parmenter, David Charles. "Spark Ignition and Spark Assisted Controlled-Auto Ignition in a Top Entry Direct-Injection Gasoline Engine." Thesis, University of Brighton, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.485951.
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An experimental study of the mixture preparation and combustion characteristics of a direct injection gasoline (G-DI) engine operating in both spark ignition (SI) and controlled-auto ignition with spark assistance (SA-CAl) is presented. The air motion, fuel distribution and combustion performance in the engine are described by the application of advanced Laser-based experimental methods and high-speed data acquisition. Determining the correct operation of the engine for spark ignition and compression ignition formed an important part of the research study. The series of experimental studies were conducted on a Ricardo Hydra singlecylinder research engine modified for optical access through the top 20mm section of the cylinder bore, as well as via a 45° mirror and flat window inserted in the crown of the Bowditch piston arrangement. The cylinder head used was based on the Ricardo Flagship concept engine with reverse tumble geometry. Two different interchangeable camshaft sets permitted both high and low valve lift configurations to be utilised. Spark ignition (SI) and controlled-auto ignition with spark assistance (SA-CAl) were achieved in the test programme. Laser-induced fluorescence (L1F), combined with simultaneous flame imaging and Particle Image Velocity (PIV) enabled qualitative in-cylinder fuel concentration measurement during fired operation and quantitative motored air motion characteristics to be determined. Simultaneous acquisition of pressure-based data during the fired studies provided a record of the in-cylinder, intake and exhaust manifold pressures. The addition of K-type thermocouples provided additional temperature information in the engine. The results attained using the above techniques showed that rates of heat release in the SA-CAl combustion mode were considerably slower than those observed in a parallel SI combustion study. This suggested that a key indicator of controlled-auto ignition (CAl) was not present in this study; it is widely considered that CAl heat release rates are of the order of those encountered in SI, when considering 4stroke operation. This result implied that flame-front propagation was the governing mechanism of fuel oxidisation in the SA-CAl mode. However, the results of the PIV studies in the SA-CAl mode suggested that the turbulence intensity was too low to support flame-front propagation in spark-initiated combustion. High-speed photography (HSP) applied in addition to the previously mentioned techniques showed that a hybrid mode of combustion exists in the SA-CAl reaction where flame front propagation could be seen to develop alongside individual sites of autoignition within the cylinder, albeit at a considerably lower rate. Images of fuel distribution in the combustion chamber acquired from the previous studies were correlated to pressure-based combustion stability data. A statistical analysis was conducted of both the SI and SA-CAl sets of data in order to determine cyclic variability within the in-cylinder fuel concentration. The results indicated higher than expected cycle-to-cycle and in-cycle variations in fuel distribution for an early injection, homogeneous charge, combustion mode when compared to those based upon the coefficient of variation in the measured indicated mean effective pressure. The L1F data. from the SA-CAl studies was found to be of far lower intensity, suggesting that the presence of high levels of exhaust residuals acted to attenuate the fluorescence signal. These findings were of particular importance to the application of the L1F technique in this manner. From the findings of the experimental techniques applied it was possible to determine from the mode of combustion encountered, SA-CAl, that a hybrid mode of fuel oxidation was occurring. It was clear that flame-front propagation was taking place, albeit at a far slower rate than in the corresponding Sl mode, as both high EGR rates and lower turbulence intensity was found to attenuate flame propagation, with further heat release occurring through diffusion burning and numerous autoignition points throughout the cylinder through the thermal energy supplied from the resident internal EGR.
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Hu, Zhengyun. "Turbulence enhancement in spark-ignition engines." Thesis, Imperial College London, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.340890.
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Posylkin, Michael. "Mixture preparation in spark-ignition engines." Thesis, Imperial College London, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.243438.
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Lind, Simon. "Distributed Ensemble Learning With Apache Spark." Thesis, Uppsala universitet, Institutionen för biologisk grundutbildning, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-274323.
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Wiseman, Marc William. "Spark ignition engine combustion process analysis." Thesis, University of Nottingham, 1990. http://eprints.nottingham.ac.uk/11131/.
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Cylinder pressure analysis is widely used in the experimental investigation of combustion processes within gasoline engines. A pressure record can be processed to reveal detail of charge burning, which is a good indicator of combustion quality. The thesis describes the evaluation of an approximate technique for calculating the mass fraction of the charge that has burnt; a novel approach for determining heat loss to the block; the development of a powerful system for combustion analysis; and the investigation of the correlation between the crank angle location of the 50% mass burnt and minimum timing advance necessary to obtain the maximum engine torque. A detailed examination has been carried out into the uncertainties in the determination of the mass fraction burnt as suggested by Rassweiler and Withrow. A revised procedure has been developed which does not require a priori identification of the combustion end point, and a new approach is suggested to calculate the polytropic indices necessary for the pressure processing. This particular implementation of the analysis is able to identify late burning and misfiring cycles, and then take appropriate steps to ensure their proper analysis. The problems associated with the assumption of uniform pressure; alignment of the pressure changes to the volume changes; pressure sampling rate; clearance volume estimation; and calibrating the acquired pressure to absolute are also evaluated. A novel method is developed to ascertain, directly from the pressure history, the heat loss to the cylinder block. Both experimental and simulated data are used to support the accuracy of the suggested heat loss evaluation, and the sensitivity of the method to its inputs is examined. The conversion of procedures for combustion analysis into a format suitable for undertaking high speed analysis is described. The analysis techniques were implemented so that the engine can be considered to be on-line to the analysis system. The system was entitled Quikburn. This system can process an unlimited number of cycles at a particular running condition, updating the screen every 1.5 seconds. The analysis system has been used to study the potentially beneficial correlation between the location of the 50% mass burnt and MBT. The correlation is examined in detail, and found to be valid except under lean fueling conditions, which is seen to be caused by slow flame initiation. It is suggested that the optimum location of the 50% mass burnt can be used as a reference setting for the ignition timing, and as an indicator of combustion chamber performance. An engine simulation was employed to verify that changes in bum shape account for the small variation seen in the optimum 50% bum locations at different operating conditions of the engine. The bum shape changes also account for the range of optimum locations of the 50% mass burnt encountered in different engines.
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Abu-Shanab, H. "Spark ignition of methane-air mixtures." Thesis, University of Leeds, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.376990.
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Gatto, Lorenzo. "Analisi e valutazione della piattaforma Spark." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amslaurea.unibo.it/8876/.
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Negli ultimi anni i dati, la loro gestione e gli strumenti per la loro analisi hanno subito una trasformazione. Si è visto un notevole aumento dei dati raccolti dagli utenti, che si aggira tra il 40 e il 60 percento annuo, grazie ad applicazioni web, sensori, ecc.. Ciò ha fatto nascere il termine Big Data, con il quale ci si riferisce a dataset talmente grandi che non sono gestibili da sistemi tradizionali, come DBMS relazionali in esecuzione su una singola macchina. Infatti, quando la dimensione di un dataset supera pochi terabyte, si è obbligati ad utilizzare un sistema distribuito, in cui i dati sono partizionati su più macchine.
Per gestire i Big Data sono state create tecnologie che riescono ad usare la potenza computazionale e la capacità di memorizzazione di un cluster, con un incremento prestazionale proporzionale al numero di macchine presenti sullo stesso. Il più utilizzato di questi sistemi è Hadoop, che offre un sistema per la memorizzazione e l’analisi distribuita dei dati. Grazie alla ridondanza dei dati ed a sofisticati algoritmi, Hadoop riesce a funzionare anche in caso di fallimento di uno o più macchine del cluster, in modo trasparente all’utente.
Su Hadoop si possono eseguire diverse applicazioni, tra cui MapReduce, Hive e Apache Spark. É su quest’ultima applicazione, nata per il data processing, che è maggiormente incentrato il progetto di tesi. Un modulo di Spark, chiamato Spark SQL, verrà posto in confronto ad Hive nella velocità e nella flessibilità nell’eseguire interrogazioni su database memorizzati sul filesystem
distribuito di Hadoop.
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Siegel, Kathryn I. (Kathryn Iris). "Incremental random forest classifiers in spark." Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/106105.
Full textAbstract:
Thesis: M. Eng., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2016.Cataloged from PDF version of thesis.
Includes bibliographical references (page 53).
The random forest is a machine learning algorithm that has gained popularity due to its resistance to noise, good performance, and training efficiency. Random forests are typically constructed using a static dataset; to accommodate new data, random forests are usually regrown. This thesis presents two main strategies for updating random forests incrementally, rather than entirely rebuilding the forests. I implement these two strategies-incrementally growing existing trees and replacing old trees-in Spark Machine Learning(ML), a commonly used library for running ML algorithms in Spark. My implementation draws from existing methods in online learning literature, but includes several novel refinements. I evaluate the two implementations, as well as a variety of hybrid strategies, by recording their error rates and training times on four different datasets. My benchmarks show that the optimal strategy for incremental growth depends on the batch size and the presence of concept drift in a data workload. I find that workloads with large batches should be classified using a strategy that favors tree regrowth, while workloads with small batches should be classified using a strategy that favors incremental growth of existing trees. Overall, the system demonstrates significant efficiency gains when compared to the standard method of regrowing the random forest.
by Kathryn I. Siegel.
M. Eng.
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Yu, Lucy M. Eng Massachusetts Institute of Technology. "Work-sharing framework for Apache Spark." Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/113441.
Full textAbstract:
Thesis: M. Eng., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2016.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (page 39).
Apache Spark is a popular framework for distributed data processing that generalizes the MapReduce model and significantly improves the performance of many use cases. People can use Spark to query enormous data sets faster than before to gain insights for a competitive edge in industry. Often these ad-hoc queries perform similar work, and there is an opportunity to share the work of different queries. This can reduce the total computation time even more. We have developed a Wrapper class which performs such optimizations. In particular, its strategy of lazy evaluation allows duplicate computation to be avoided and multiple related Spark jobs to be executed at the same time, reducing the scheduling overhead. Overall, the system demonstrates significant efficiency gains when compared to default Spark.
by Lucy Yu.
M. Eng.
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Brundin, Michelle. "Data Stream Queries to Apache SPARK." Thesis, Uppsala universitet, Institutionen för informationsteknologi, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-301326.
Full textAbstract:
Many fields have a need to process and analyze data streams in real-time. In industrial applications the data can come from big sensor networks, where the processing of the data streams can be used for performance monitoring and fault detection in real time. Another example is in social media where data stream processing can be used to detect and prevent spam. A data stream management system (DSMS) is a system that can be used to manage and query continuously received data streams. The queries a DSMS executes are called continuous queries (CQs). In contrast to regular database queries they execute continuously until canceled. SCSQ is a DSMS developed at Uppsala university. Apache Spark is a large scale general data processing engine. It has, among other things, a component for data stream processing, Spark Streaming. In this project a system called SCSQ Spark Streaming Interface (SSI) was implemented that allows Spark Streaming applications to be called from CQs in SCSQ. It allows the Spark Streaming applications to receive input streams from SCSQ as well as emitting resulting stream elements back to SCSQ. To demonstrate SSI, two examples are shown where it is used for stream clustering in CQs using the streaming k-means implementation in Spark Streaming.
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AL, Jorani Salam. "Performance assessment of Apache Spark applications." Thesis, Linnéuniversitetet, Institutionen för datavetenskap och medieteknik (DM), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-80181.
Full textAbstract:
This thesis addresses the challenges of large software and data-intensive systems. We will discuss a Big Data software that consists of quite a bit of Linux configuration, some Scala coding and a set of frameworks that work together to achieve the smooth performance of the system. Moreover, the thesis focuses on the Apache Spark framework and the challenging of measuring the lazy evaluation of the transformation operations of Spark. Investigating the challenges are essential for the performance engineers to increase their ability to study how the system behaves and take decisions in early design iteration. Thus, we made some experiments and measurements to achieve this goal. In addition to that, and after analyzing the result we could create a formula that will be useful for the engineers to predict the performance of the system in production.
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McIlroy, Colin William. "Muriel Spark and the Romantic ideal." Thesis, University of Glasgow, 2015. http://theses.gla.ac.uk/6439/.
Full textAbstract:
By narrowing the disparate and often contradictory trajectories of Romantic thought into a compressed framework, this thesis seeks to scrutinise the treatment of the Romantic ideal in the fiction of Muriel Spark. A number of recurring themes can be understood to collectively constitute this Romantic ideal. These include Coleridge’s theory of the power of the imagination to coalesce disparities into unity and harmony. The relationship between creativity and psychosis in The Comforters (1957) is considered within a wider discussion on the nature of creativity and the conception of the visionary Romantic artist. This leads to an investigation of the Romantic Movement’s emphasis on interiority and the self, and the influence of John Henry Newman in The Mandelbaum Gate (1965). The resulting discussion treats the concepts of transfiguration and the sublime as they relate to individual subjectivity in The Driver’s Seat (1970). The Romantic fascination with the reinvigoration of myth, legend and oral narrative cultures is examined in relation to The Ballad of Peckham Rye (1960), and the discussion returns to unity, harmony, vision, and the artist in The Finishing School (2004). The investigation of these elements of the Romantic ideal highlights a number of corollary questions. The emphasis on the self prompts the examination of Spark’s engagement with the themes of solipsism, ego, and performance, while Keats’ ‘Negative Capability’ is considered in the attempt to comprehend the other. The methodology will be comparative textual analysis with reference to relevant extant criticism, alongside consideration of literature from anthropology and folklore studies. By illuminating previously overlooked connections with Romanticism and Romantic literary methodologies, this interdisciplinary approach will assist in ascertaining whether Spark’s sustained engagement with these themes is evidence of a complex, multivalent relationship with the Romantic ideal, or whether recent criticism positing her rejection of Romanticism can be upheld.
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Mutzke, Johannes Gerhard. "Abnormal combustion in spark ignition engines." Thesis, University of Oxford, 2018. http://ora.ox.ac.uk/objects/uuid:0bba0e6c-a989-4791-a80a-8b39fe88f431.
Full textAbstract:
Emissions from internal combustion engines are a major contributor to anthropogenic climate change. In order to decrease the amount of emissions, car manufacturers are investing in increasing the efficiency of spark ignition engines. Means for this include downsizing and turbocharging which come with an exacerbated risk of abnormal and harmful combustion phenomena, notably autoignition, knock and pre-ignition and thus pose a limit to the efficiency of the engines. Abnormal combustion depends on the engine geometry, the operating conditions and the fuel. Industrial standard classification systems are outlined to be insufficient, misleading or non-existent for modern engines and fuels. This thesis aims to improve the understanding of the abnormal combustion phenomena through an experimental project which can be utilised for improved classification systems. The vast majority of the experiments were conducted on a variable compression ratio engine which was fitted with modern control, measurement and data acquisition equipment to resemble an industrially-used test engine. In a first study, methods of finding the ideal engine operating point were investigated. Knock was induced in the engine, and knock indicators and limitations of knock are discussed here. Enhanced humidity was passed into the heated air-inlet stream by means of a custom-built humidifying unit. Results showed that both the power output of the engine and the severity of knock were reduced with increased humidity. This was explained by the exclusion of combustible air. A fuel-vaporization unit allowed for experiments with fully vaporized fuel. It could be shown that this had an adverse effect on knock as the cooling effect of the enthalpy of vaporization was removed. A second study employed a temperature-controlled glow plug to induce surface pre-ignition. A range of analysis techniques were tested and discussed which ranged from flame ionization detection to several in-cylinder pressure based methods. A cycle-by-cycle analysis with a maximum pressure method revealed an unexpected trend of surface pre-ignition tendency in sweeps of stoichiometry and fuels, with slightly weak of stoichiometric mixtures being the most susceptible to pre-ignition. Enhanced humidity had a negligible effect on surface pre-ignition under real world conditions. A third study concerned itself with the analysis of knock-induced heat flux, which is both a major cause for damage to the engine and trigger for surface pre-ignition. A heat flux probe was fitted to the engine and results linking heat flux to knock could be obtained on cycle-by-cycle basis and cycleaveraged basis. A linear trend between heat flux and knock intensity was found.
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Nates, Roy Jonathan. "Knock damage in spark-ignition engines." Doctoral thesis, University of Cape Town, 1995. http://hdl.handle.net/11427/11478.
Full textAbstract:
The objectives of this thesis were to identify, explain and quantify the damage caused by knocking combustion in spark-ignition engines. A literature review indicated that, in general, research into knock has focused on the causes and avoidance of knock, rather than on the damage resulting from knock. The few published works concerning the effects of knock were mainly interested in the prevention of one specific form of damage, namely piston erosion. The review highlighted the need to investigate the relationship between knock and the various forms of damage. Using the evidence from knock-damaged engines, the sequence of events leading to failure were reconstructed. The manner in which knock damage manifests itself as surface erosion, piston-ring failure, piston-land cracking, piston blow-by and seizure were examined. From these observations it was deduced that two independent damage paths result from knock. Consequently, the research diverged into two studies, namely: Local pressure-temperature transients in the end-gas zone which cause localised erosion damage; Excessive heat flux associated with knocking combustion which results in global piston and ring problems.
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Mohyedin, Kermani Ehsan. "Distributed linear programming with Apache Spark." Thesis, University of British Columbia, 2016. http://hdl.handle.net/2429/59990.
Full textAbstract:
For this thesis project, we have implemented Mehrotra's predictor-corrector interior point algorithm on top of Apache Spark for solving large-scale linear programming problems. Our large-scale solver (Spark-LP) is unique because it is open-source, fault-tolerant and can be used on commodity cluster of machines. As a result, Spark-LP provides an opportunity to solve large-scale problems at the lowest possible cost. We have assessed the performance and convergent results of our solver on self-generated, sparse and dense large-scale problems over small to medium-sized clusters, composed of 16 to 64 Amazon's Elastic Computing Cloud r3.xlarge instances.
In conclusions, we have made important suggestions for breaking the current structural limitations so that our solver can be used on heterogeneous clusters containing CPUs and GPUs on JVM environment without the usual numerical
limitations and overheads.Science, Faculty of
Computer Science, Department of
Graduate
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Capuccini, Marco. "Structure-Based Virtual Screening in Spark." Thesis, Uppsala universitet, Institutionen för farmaceutisk biovetenskap, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-257028.
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Fu, Xinye. "Building Evolutionary Clustering Algorithms on Spark." Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-219608.
Full textAbstract:
Evolutionary clustering (EC) is a kind of clustering algorithm to handle the noise of time-evolved data. It can track the truth drift of clustering across time by considering history. EC tries to make clustering result fit both current data and historical data/model well, so each EC algorithm defines snapshot cost (SC) and temporal cost (TC) to reflect both requests. EC algorithms minimize both SC and TC by different methods, and they have different ability to deal with a different number of cluster, adding/deleting nodes, etc.Until now, there are more than 10 EC algorithms, but no survey about that. Therefore, a survey of EC is written in the thesis. The survey first introduces the application scenario of EC, the definition of EC, and the history of EC algorithms. Then two categories of EC algorithms model-level algorithms and data-level algorithms are introduced oneby-one. What’s more, each algorithm is compared with each other. Finally, performance prediction of algorithms is given. Algorithms which optimize the whole problem (i.e., optimize change parameter or don’t use change parameter to control), accept a change of cluster number perform best in theory.EC algorithm always processes large datasets and includes many iterative data-intensive computations, so they are suitable for implementing on Spark. Until now, there is no implementation of EC algorithm on Spark. Hence, four EC algorithms are implemented on Spark in the project. In the thesis, three aspects of the implementation are introduced. Firstly, algorithms which can parallelize well and have a wide application are selected to be implemented. Secondly, program design details for each algorithm have been described. Finally, implementations are verified by correctness and efficiency experiments.Evolutionär clustering (EC) är en slags klustringsalgoritm för att hantera bruset av tidutvecklad data. Det kan spåra sanningshanteringen av klustring över tiden genom att beakta historien. EC försöker göra klustringsresultatet passar både aktuell data och historisk data / modell, så varje EC-algoritm definierar ögonblicks kostnad (SC) och tidsmässig kostnad (TC) för att reflektera båda förfrågningarna. EC-algoritmer minimerar både SC och TC med olika metoder, och de har olika möjligheter att hantera ett annat antal kluster, lägga till / radera noder etc.Hittills finns det mer än 10 EC-algoritmer, men ingen undersökning om det. Därför skrivs en undersökning av EC i avhandlingen. Undersökningen introducerar först applikationsscenariot för EC, definitionen av EC och historien om EC-algoritmer. Därefter introduceras två kategorier av EC-algoritmer algoritmer på algoritmer och algoritmer på datanivå en för en. Dessutom jämförs varje algoritm med varandra. Slutligen ges resultatprediktion av algoritmer. Algoritmer som optimerar hela problemet (det vill säga optimera förändringsparametern eller inte använda ändringsparametern för kontroll), acceptera en förändring av klusternummer som bäst utför i teorin.EC-algoritmen bearbetar alltid stora dataset och innehåller många iterativa datintensiva beräkningar, så de är lämpliga för implementering på Spark. Hittills finns det ingen implementering av EG-algoritmen på Spark. Därför implementeras fyra EC-algoritmer på Spark i projektet. I avhandlingen införs tre aspekter av genomförandet. För det första är algoritmer som kan parallellisera väl och ha en bred tillämpning valda att implementeras. För det andra har programdesigndetaljer för varje algoritm beskrivits. Slutligen verifieras implementeringarna av korrekthet och effektivitetsexperiment.
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Schild, Ilissa Brooke. "Influence of Spark Energy, Spark Number, and Flow Velocity on Detonation Initiation in a Hydrocarbon-fueled PDE." Thesis, Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/7527.
Full textAbstract:
Pulsed Detonation Engines (PDEs) have the potential to revolutionize fight by better utilizing the chemical energy content of reactive fuel/air mixtures over conventional combustion processes. Combustion by a super-sonic detonation wave results in a significant increase in pressure in addition to an increase in temperature. In order to harness this pressure increase and achieve a high power density, it is desirable to operate PDEs at high frequency. The process of detonation initiation impacts operating frequency by dictating the length of the chamber and contributing to the overall cycle time. Therefore a key challenge in the development of a practical PDEs is the requirement to rapidly initiate a detonation in hydrocarbon-air mixtures. This thesis evaluates the influence of spark energy and airflow velocity on this challenging initiation process. The influence of spark energy, number of sparks and airflow velocity on Deflagration-to-Detonation Transition (DDT) was studied during cyclic operation of a small-scale PDE at the General Electric Global Research Center. Experiments were conducted in a 50 mm square transitioning to cylindrical channel PDE with optical access operating with stoichiometric ethylene-air mixture. Total spark energy was varied from 250 mJ to 4 J and was distributed between one and four spark plugs located in the same axial location. Initial flame acceleration was imaged using high-speed shadowgraph and was characterized by the time to reach 20 cm from the spark plug. Measurements of detonation wave velocity and emergence time, the time it takes the detonation wave to exit the tube, was measured using dynamic pressure transducers and ionization probes. It was found that the flame front spread was faster at higher spark energies and with more spark locations. Initial flame acceleration was 16% faster for the 4-spark, 4 J case when compared to the baseline 1-spark, 1 J case. When looking at the effect of airflow on the influence of spark energy, it was found that airflow had a larger effect on emergence time at high energies, versus energies less than 1 J. Finally, for a selected case of 0.25 J spark energy and 4 sparks, the velocity of the fuel-air mixture during fill was found to have a varying influence on detonation initiation and emergence time.
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Mohamad, Taib Iskandar. "Development of a spark plug fuel injector for direct injection of natural ags in spark ignition engine." Thesis, Cranfield University, 2006. http://hdl.handle.net/1826/4436.
Full textAbstract:
In the name of God, The Most Gracious, The Most Merciful. By His will, this thesis has
been completed as another episode of knowledge seeking and contribution.
The author wishes to express a greatest gratitude to the academic supervisor for this project,
Dr. Matthew Harrison and Professor Douglas Greenhalgh for their warmth, continuous
guidance and support, priceless knowledge and expertise, and kindly understanding.
Secondly, author's deepest appreciation to Dr. Mark Jermy, the initial supervisor for this
project, for his ideas, understanding, support, availability and generosity for providing
assistance both in author's academic and private life.
To my mother and father whose supplications and encouragements have given me strength
to complete this work. To my family whose support during this course of studies has given
me comfort. To my parents in-law and siblings in-law, thank you for your support.
My dearest gratitude to the beloved wife, Ira for standing by my side and giving me
continuous support throughout this course of study and the hardship of life due to it. Your
sacrifice is priceless. To my children, Balgis, Naufal, Nadiyah and Safiyah, you are my source
of inspirations.
A special thank to Dr. Glenn Sherwood, Tim Lee, Brian Scully, Richard Kennewell, Alan
Hutching, and all others for providing technical supports during the experiment works.
To Andreas, Eudoxios, Anni, Edouard, Fatiha, Alessio, Andy and Adam, I thank you all for
the friendship and helps during my studies.
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Mohamad, Taib Iskandar. "Development of a spark plug fuel injector for direct injection of natural gas in spark ignition engine." Thesis, Cranfield University, 2006. http://dspace.lib.cranfield.ac.uk/handle/1826/4436.
Full textAbstract:
The use of methane in spark ignition engines is mainly due to its cleaner emissions and relatively low price. However, when methane replaces gasoline in the externally mixing carburettor or port injection engine, power is reduced and upper speed is limited. These are because the burning velocity of methane is slower than of gasoline, and some air is displaced in the intake manifold in order to compensate the low density methane. The problem can be mitigated when fuel is directly injected into the combustion chamber after the intake valve closes. This results in an increased volumetric efficiency, a higher absolute heating value of mixture and a faster burning rate. The work presented in this thesis aims to develop a conversion system that enables methane to be directly injected into the combustion chamber of a spark ignition engine without modifying the original structure of the engine. The system, named as Spark Plug Fuel Injector (SPFI) combines a fuel injector with a spark plug. A fuel path is drawn along the periphery of the spark plug body to deliver the injected fuel to the combustion chamber. The system was installed and tested on a Ricardo E6 single cylinder engine with compression ratio of 10.5: 1. Cylinder pressures were taken as the main indicator of the engine performance and selected indicated performance were presented. A set of port injected data for the engine running on methane was also taken in order to provide a comparison of performance with SPFI direct injection. Results show that the indicated performance of the SPFI methane direct injection at the tested speed was lower than the optimised methane port injection operation. This was mainly due to the quality of air-fuel mixing, which is a result of spatial and temporal limitation of direct injection operation. Flow visualization using the PLIF method shows that even though sufficient gas jet penetration from SPFI injection nozzle was achieved, the cone angle was very narrow. The conclusion from imaging experiments implies poor mixing, hence the performance suffers drawback. However, with direct injection, volumetric efficiency is increased ands combustion duration is faster. These two factors are desirable for engine performance improvement. SPFI has proven to be a practical and low cost conversion to methane. Even though the performance is lower than port injection, its benefits are significant. As the SPFI design is simple and requires no modification to the original structure of the converted engine.
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Lustig, Michael. "Sparse MRI /." May be available electronically:, 2008. http://proquest.umi.com/login?COPT=REJTPTU1MTUmSU5UPTAmVkVSPTI=&clientId=12498.
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Ramachandran, Shridhar. "Incremental PageRank acceleration using Sparse Matrix-Sparse Vector Multiplication." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1462894358.
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Thorén, Elina. "Sparka uppåt : En undersökning om satir i litteraturen." Thesis, Uppsala universitet, Litteraturvetenskapliga institutionen, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-201467.
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Powell, Ryan. "Urban sprawl in Reno-Sparks, Washoe County, Nevada." abstract and full text PDF (free order & download UNR users only), 2007. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1442855.
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Jackson, Julie Kay Cropper. "What sparks interest in science? : a naturalistic inquiry /." Digital version accessible at:, 2000. http://wwwlib.umi.com/cr/utexas/main.
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Pratt-Smith, Stella. "Creative sparks : literary responses to electricity, 1830-1880." Thesis, University of Oxford, 2011. http://ora.ox.ac.uk/objects/uuid:68d9c5fd-21ad-4ebb-8348-f0d4531be5bb.
Full textAbstract:
This thesis examines accounts of electricity in journalism, short stories, novels, poetry and instructional writings, composed between 1830 and 1880 by scientific investigators, popular practitioners and fiction authors. The writings are approached as diverse and often incongruous impressions of electricity, in which the use of figurative and narrative techniques brings into question distinctions between science and literature. It is proposed that the unusual combination of electricity’s historical characterisation as an elixir vitae, intense investigation by contemporary scientists, and close alliance with new technologies offered unique opportunities for imaginative speculation. The thesis contends that engaging with these conflicting characteristics created a synthesis of scientific, social and literary responses that defy epistemological and generic categorisation. Fictionality is approached in chapter two as a central feature of scientific conceptualisation, experiment and discovery, particularly in the work of Michael Faraday and James Clerk Maxwell. In chapters three and four, the landscape of popular non-fiction books and periodicals is mapped, to show the ways in which the period’s publication contexts and forums, reading patterns, and use of literary practices contributed to wider engagement with ideas about electricity. Chapters five and six focus on fiction writings, identifying parallels and divergences between actual electrical science and its fictional portrayal. Short stories are shown to have emphasised associations between electricity, neurosis, deformity and the occult, complicating contemporary scientific optimism and presenting electricity as an alluring yet dangerous phenomenon, which disordered the natural world and man’s relationship with it. These characteristics are identified further in the metaphorical references of several canonical novelists, in the exploitation of electricity, elixirs and power depicted by William Harrison Ainsworth and Edward Bulwer-Lytton, and through a case study of the text and reception of a popular novel about electricity by Benjamin Lumley. The thesis contends that electricity’s anomalous and protean nature produced distinctively hybrid responses that enhance our understanding of contemporary popular writing, its contexts and how it was read.
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Groff, Jeffrey R. "Markov chain models of calcium puffs and sparks." W&M ScholarWorks, 2008. https://scholarworks.wm.edu/etd/1539623333.
Full textAbstract:
Localized cytosolic Ca2+ elevations known as puffs and sparks are important regulators of cellular function that arise due to the cooperative activity of Ca2+-regulated inositol 1,4,5-trisphosphate receptors (IP3Rs) or ryanodine receptors (RyRs) co-localized at Ca2+ release sites on the surface of the endoplasmic reticulum or sarcoplasmic reticulum. Theoretical studies have demonstrated that the cooperative gating of a cluster of Ca2+-regulated Ca 2+ channels modeled as a continuous-time discrete-state Markov chain may result in dynamics reminiscent of Ca2+ puffs and sparks. In such simulations, individual Ca2+-release channels are coupled via a mathematical representation of the local [Ca2+] and exhibit "stochastic Ca2+ excitability" where channels open and close in a concerted fashion. This dissertation uses Markov chain models of Ca 2+ release sites to advance our understanding of the biophysics connecting the microscopic parameters of IP3R and RyR gating to the collective phenomenon of puffs and sparks.;The dynamics of puffs and sparks exhibited by release site models that include both Ca2+ coupling and nearest-neighbor allosteric coupling are studied. Allosteric interactions are included in a manner that promotes the synchronous gating of channels by stabilizing neighboring closed-closed and/or open-open channel pairs. When the strength of Ca2+-mediated channel coupling is systematically varied, simulations that include allosteric interactions often exhibit more robust Ca2+ puffs and sparks. Interestingly, the changes in puff/spark duration, inter-event interval, and frequency observed upon the random removal of allosteric couplings that stabilize closed-closed channel pairs are qualitatively different than the changes observed when open-open channel pairs, or both open-open and closed-closed channel pairs are stabilized. The validity of a computationally efficient mean-field reduction applicable to the dynamics of a cluster of Ca2+-release Ca2+ channels coupled via the local [Ca2+] and allosteric interactions is also investigated.;Markov chain models of Ca2+ release sites composed of channels that are both activated and inactivated by Ca2+ are used to clarify the role of Ca2+ inactivation in the generation and termination of puffs and sparks. It is found that when the average fraction of inactivated channels is significant, puffs and sparks are often less sensitive to variations in the number of channels at release sites and the strength of Ca2+ coupling. While excessively fast Ca2+ inactivation can preclude puffs and sparks moderately fast Ca2+ inactivation often leads to time-irreversible puff/sparks whose termination is facilitated by the recruitment of inactivated channels throughout the duration of the puff/spark event. On the other hand, Ca2+ inactivation may be an important negative feedback mechanism even when its time constant is much greater than the duration of puffs and sparks. In fact, slow Ca 2+ inactivation can lead to release sites with a substantial fraction of inactivated channels that exhibit nearly time-reversible puffs and sparks that terminate without additional recruitment of inactivated channels.
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Aycock, John Daniel. "Practical Earley parsing and the SPARK toolkit." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/NQ58556.pdf.
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Sorrell, A. J. "Spark ignition engine performance during warm-up." Thesis, Brunel University, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234957.
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Grant, Andrew J. "Laser diagnostics of spark-ignited combustion systems." Thesis, University of Oxford, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.343481.
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Ahmed, S. F. A. F. S. "Spark ignition of turbulent non-premixed flames." Thesis, University of Cambridge, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.595391.
Full textAbstract:
This thesis investigates the spark ignition of various turbulent non-premixed flames namely, jet, counter-flow and bluff-body flames. This detailed fundamental study of spark ignition aims to provide useful information for solving the high-altitude relight problem in the aviation gas turbine. A specially designed ignition unit has been built. Different spark parameters and flow conditions have been examined to study their effects on the ignition probability defined as successful flame establishment. The ignition probability results have been correlated with the measured or estimated flow velocity and mixture fraction. The whole ignition and flame propagation events have been visualized by a high-speed camera and OH-PLIF. In the jet flames, it was found that after an initially spherical shape, the flame took a cylindrical shape with a propagating edge upstream. The probability of successful ignition Pign increases with high spark energy, thin electrode diameter and wide gap, but decreases with increasing dilution of the jet with air. The flame kernel growth rate is high when the ignition probability is high for all parameters, except for jet velocity. Increasing the jet velocity decreases the ignition probability at all locations. The estimated net propagation speed relative to the incoming flow was about 3 to 6 laminar burning velocities of a stoichiometric mixture SL. In the counter-flow flames, it was found that the flame spread as an edge flame with a large scatter in its radial position. Pign decreased with bulk velocity, which suggests that the local strain rate can be detrimental to ignition so that, even with the strongest spark tested, ignition could not be achieved at a bulk velocity about 90% of the extinction velocity. Pign was greater than zero even in regions well into the fuel and air streams where the mixture fraction fluctuations were virtually zero, giving zero probability of finding flammable mixture at the spark location. The estimated edge flame speed relative to the radial flow is higher than SL for the premixed flame and is less than SL for the non-premixed flames.
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Koutsoumpakis, Georgios. "Spark-based Application for Abnormal Log Detection." Thesis, Uppsala universitet, Institutionen för informationsteknologi, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-233335.
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Ericsson is a world-leader in the rapidly-changing environment of communications technology and thus it is important to provide reliable and high quality networks. Automated test loops are executed frequently, trying to find problems in Ericsson's products but, since test cases alone are not always adequate, machine learning techniques are sometimes used to find abnormal system behaviour. The Awesome Automatic Log Analysis Application (AALAA) tries to find such behaviour by checking the log files produced during the testing, using machine learning techniques. Unfortunately, its performance is not sufficient as it requires a lot of time to process the logs and to train the model. This thesis manages to improve AALAAs performance by implementing a new version that uses Apache Spark, a general purpose cluster computing system, for both the processing of the data and for the training of the machine learning algorithm.
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Thornhill, Michael Joseph. "Idle speed control of spark ignited engines." Thesis, Queen's University Belfast, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.286863.
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