Academic literature on the topic 'Long spark'

В работе обсуждается проблема определения адекватности статистической модели, которая описывает поражение объектов длинной искрой. Показана необходимость дополнительных исследований по выбору методов, которые обеспечивают проверку согласия результатов моделирования и экспериментального распределения точек поражения плоскости.<br>The paper discusses the problem of determining the adequacy of the statistical model, which describes the defeat of objects using long sparks. It has been shown that more research is needed on the choice of methods that provide verification agreement of simulation results and experimental plane distribution points defeat.

Due to the continuous work in the automobile industry to reduce the environmental impact, reduce fuel consumption and increase efficiency, new technologies need to be developed and implemented in vehicles. For spark ignited engines, one technology that has received more attention in recent years is long route Exhaust Gas Recirculation (EGR), which means that exhaust gases after the turbine are transported back to the volume before the compressor in the air intake system of the engine. In this work, the components of the long route EGR system is modeled with mean value engine models in Simulink, and implemented in a existing Simulink engine model. Then different methods for estimating the mass flow over the long route EGR system are compared, and the transport delays for the recirculated exhaust gases in the engines air intake system are modeled. This work is based on measurements done on an engine rig, on which a long route EGR system was installed. Finally, some ideas on how a long route EGR system on a gasoline engine can be controlled are presented based on the results in this thesis work.

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.

Thesis (M.B.A.)--Massachusetts Institute of Technology, Sloan School of Management; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering; in conjunction with the Leaders for Global Operations Program at MIT, 2011.<br>Vita. Cataloged from PDF version of thesis.<br>Includes bibliographical references (p. 59-60).<br>This thesis develops an optimal inventory model for repairable and long leadtime spare parts for an Engine overhaul business. In addition, it presents a business case for centralization of inventory. Pratt & Whitney purchased the Norway Engine Center (NEC) in 2000. Two new engine centers, the Shanghai Engine Center (SEC) and the Turkey Engine Center (TEC) opened as joint ventures in 2009. While all three engine centers overhaul the same engine, they each make independent decisions regarding material strategy. Operations are expected to grow substantially at the two newest centers. Current inventory practices are not sustainable as operations expand. In addition, the overhaul business is a competitive market and there is growing pressure to decrease engine turn-around-time (TAT). An optimal material strategy is needed to reduce the material sourcing time and therefore reduce overall TAT. This project develops an inventory strategy that will significantly reduce TAT with minimal additional inventory investment. To accomplish this, an inventory model was developed to determine the optimal inventory level and then using this model, the business case for using centralization to reduce both holding cost and material sourcing time was investigated. All inventory in the engine centers were considered in this project, however rotable material became the focus of this research as it has the largest impact on the engine center through its high value and long lead-times. Rotable material is inventory used to buffer against the lead-time of parts out for repair. In the engine overhaul business material sourcing time is built into the process. This means that material is not needed immediately but rather after some specified amount of time. This feature is central to the rotable inventory model. The model determines the mean and variance of the excess lead-time - the portion of the lead-time that occurs after the specified time allotted. The excess lead-time is used to determine the optimal reorder point. Using this model, we show that centralization of rotable material will reduce inventory value by more than 30% over the current decentralized system both using the current TAT as well as the proposed TAT.<br>by Tyeliah Elaine Duncan.<br>S.M.<br>M.B.A.

This thesis presents an investigation on the signatures of corona discharges from grounded rods under thunderstorms and in the laboratory, with optical detections in the 337/777 nm wavelengths for high voltage sparks. This PhD project is contextualized in the European program: Science and Innovation with thunderstorms (SAINT), funded by the Horizon 2020 / Marie Sklodowska Curie Action (Grant agreement ID: 722337). Under conditions of electrification, charged clouds produce an enhancement of the electric field at the ground level. That, in turn, can lead to corona discharges that produce a space charge layer in the vicinity of grounded structures. The study of this phenomenon is useful for the understanding of lightning-related processes and attachment. In addition to the electrical current obtained from the discharges, another important variable is the optical signature generated by the plasma channels. Emissions in many spectra lines associated with reactions of streamers and leaders with the main components of the atmosphere are relevant for visual observations. This work presents a chapter for current literature review of the processes associated with lightning and the main concepts applied. Then, a detailed description of the instrumentation available for the tests carried out in the laboratory and in the field is provided. The first article of this compendium presents data obtained with experiments of a grounded rod under high background electric field in the laboratory and the field. A limited number of works in the literature have presented such data. An analysis correlating pulse frequency, electric field level and average wind speed is the main novelty of the article. A congress paper annexed in the thesis complements the findings comparing the discharges observed at two other experimental sites. The second article describes a compilation of results obtained in the laboratory for investigating optical signatures in two specific lines of the spectra (337 nm and 777 nm), the ones with stronger emissions in lightning-like events. There is special relevance of such experiments for supporting satellite-based observations of lightning by the Atmosphere-Space Interactions Monitor (ASIM) that perform optical measurements in the same wavelength ranges and the operational lightning imagers such as Geostationary Lightning Mapper (GLM) and the future Meteosat Third Generation Lightning Imager (MTG-LI). The conclusions are presented, together with the prospects for future work following the original results achieved with this PhD. This thesis ends with a detailed description of the dissemination activities (presentation at seminars and conferences, coauthored publications in journals and at conferences) and training activities received throughout this project. Finally, the appendix present additional developments and applications of the sensor developed during this doctorate, comprising experiments performed during a two-month internship at the Eindhoven University of Technology (TU/e), and one section with results for the use of photometers to determine the initiation of an upward leader. Such experiments are particularly interesting for understanding space charge production and in the validation of lightning rods. The concepts applied to the development of a corona discharge current sensor were patented together with Dena Desarrollos, the company where the investigations were carried out during this doctorate.<br>Esta tesis presenta una investigación sobre las huellas de descargas de corona en pararrayos durante tormentas eléctricas y en el laboratorio, con detecciones ópticas en las longitudes de onda de 337/777 nm para descargas de alto voltaje. Este proyecto de doctorado se contextualiza en el programa europeo: Science and Innovation with thunderstorms (SAINT), financiado por la Acción Horizon 2020 / Marie Sklodowska Curie (Acuerdo de subvención ID: 722337). En condiciones de electrificación, las nubes cargadas producen un aumento del campo eléctrico a nivel del suelo. Eso, a su vez, puede ocasionar descargas de corona que producen una capa de carga espacial en las proximidades de las estructuras conectadas a tierra. El estudio de este fenómeno es útil para comprender los procesos y la conexión de los canales de los rayos. Además de la corriente eléctrica obtenida de las descargas, otra variable importante es la huella óptica (las señales ópticas a lo largo del tiempo) generada por los canales de plasma. Las emisiones en muchas líneas espectrales asociadas con reacciones de streamers y líderes con los componentes principales de la atmósfera son relevantes para las observaciones visuales. Este trabajo presenta un capítulo de revisión de la literatura actual sobre los procesos asociados a las descargas atmosféricas y los principales conceptos aplicados. A continuación, se realiza una descripción detallada de la instrumentación disponible para las pruebas realizadas en laboratorio y en campo. El primer artículo de este compendio presenta datos obtenidos con experimentos de una varilla puesta a tierra sujeta a un campo eléctrico de fondo elevado en laboratorio y en campo. Un número limitado de trabajos en la literatura han presentado dichos datos. Un análisis que correlaciona la frecuencia del pulso, el nivel del campo eléctrico y la velocidad media del viento es la principal novedad del artículo. Un artículo presentado en congreso adjunto a la tesis complementa los resultados y realiza una comparación de las descargas observadas en otros dos sitios experimentales. El segundo artículo presenta una recopilación de resultados obtenidos en el laboratorio para la investigación de la huella óptica en dos líneas específicas de los espectros (337 nm y 777 nm), las que tienen emisiones más intensas en los rayos. Existe una relevancia especial de dichos experimentos para respaldar las observaciones de rayos basadas en satélites por el Monitor de Interacciones Atmosfera-Espacio (ASIM) que realiza mediciones ópticas en los mismos rangos de longitud de onda y los generadores de imágenes de rayos operacionales como Geostationary Lightning Mapper (GLM) y el futuro Meteosat Third Generation Lightning Imager (MTG-LI). Se presentan las conclusiones, junto con las perspectivas de trabajo futuro siguiendo los resultados originales alcanzados con este doctorado. Esta tesis finaliza con una descripción detallada de las actividades de difusión (presentación en seminarios y congresos, publicaciones en coautoría en revistas y congresos) y actividades formativas recibidas a lo largo de este proyecto. Finalmente, el apéndice presenta desarrollos y aplicaciones adicionales del sensor desarrollado durante este doctorado, que comprende experimentos realizados durante período de prácticas de dos meses en la Universidad Tecnológica de Eindhoven (TU/e), y un apartado con resultados para el uso de fotómetros para determinar la iniciación de un líder ascendente. Estos experimentos son particularmente interesantes para comprender la producción de cargas espaciales y en la validación de pararrayos. Los conceptos aplicados al desarrollo del sensor de corriente de descarga corona fueron patentados junto con Dena Desarrollos, empresa donde se llevaron a cabo las investigaciones durante este doctorado.<br>Enginyeria Elèctrica

The correlation of several events in a period of time is a necessity for a threat detection platform. In the case of multistep attacks (attacks characterized by a sequence of executed commands), it allows detecting the different steps one by one and correlating them to raise an alert. It also allows detecting abnormal behaviors on the IT system, for example, multiple suspicious actions performed by the same account. The correlation of security events increases the security of the system and reduces the number of false positives. The correlation of the events is made thanks to pre- existing correlation rules. The goal of this thesis is to evaluate the feasibility of using a correlation engine based on Apache Spark. There is a necessity of changing the actual correlation system because it is not scalable, it cannot handle all the incoming data and it cannot perform some types of correlation like aggregating the events by attributes or counting the cardinality. The novelty is the improvement of the performance and the correlation capacities of the system. Two systems are proposed for correlating events in this project. The first one is based on Apache Spark Structured Streaming and analyzed the flow of security logs in real- time. As the results are not satisfactory, a second system is implemented. It uses a more traditional approach by storing the logs into an Elastic Search cluster and does correlation queries on it. In the end, the two systems are able to correlate the logs of the platform. Nevertheless, the system based on Apache Spark uses too many resources by correlation rule and it is too expensive to launch hundreds of correlation queries at the same time. For those reasons, the system based on Elastic Search is preferred and is implemented in the workflow.<br>Korrelation av flera händelser under en viss tidsperiod är en nödvändighet för plattformen för hotdetektering. När det gäller attacker i flera steg (attacker som kännetecknas av en sekvens av utförda kommandon) gör det möjligt att upptäcka de olika stegen ett efter ett och korrelera dem för att utlösa en varning. Den gör det också möjligt att upptäcka onormala beteenden i IT- systemet, t.ex. flera misstänkta åtgärder som utförs av samma konto. Korrelationen av säkerhetshändelser ökar systemets säkerhet och minskar antalet falska positiva upptäckter. Korrelationen av händelserna görs tack vare redan existerande korrelationsregler. Målet med den här avhandlingen är att utvärdera genomförbarheten av en korrelationsmotor baserad på Apache Spark. Det är nödvändigt att ändra det nuvarande korrelationssystemet eftersom det inte är skalbart, det kan inte hantera alla inkommande data och det kan inte utföra vissa typer av korrelation, t.ex. aggregering av händelserna efter attribut eller beräkning av kardinaliteten. Det nya är att förbättra systemets prestanda och korrelationskapacitet. I detta projekt föreslås två system för korrelering av händelser. Det första bygger på Apache Spark Structured Streaming och analyserade flödet av säkerhetsloggar i realtid. Eftersom resultaten inte var tillfredsställande har ett andra system införts. Det använder ett mer traditionellt tillvägagångssätt genom att lagra loggarna i ett Elastic Searchkluster och göra korrelationsförfrågningar på dem. I slutändan kan de två systemen korrelera plattformens loggar. Det system som bygger på Apache Spark använder dock för många resurser per korrelationsregel och det är för dyrt att starta hundratals korrelationsförfrågningar samtidigt. Av dessa skäl föredras systemet baserat på Elastic Search och det implementeras i arbetsflödet.

The master´s thesis deals with long-term assets. It contains analysis of differences in appreciation of the long-term assets between czech accounting legislation and international accounting standards IFRS/IAS, and succesive application of ascertained differences into the corporate enterprise with the target to find out the impact on trading income.

碩士<br>國立虎尾科技大學<br>資訊工程系碩士班<br>107<br>The main reason for the low usage rate of long-term care 2.0 is that most people do not understand the long-term care 2.0 system, and how to improve the awareness and usage of long-term care is the main purpose of this study. This study proposes to Integrating LSI, K-means and K-NN into Semantic Cloud Framework (ILKKSCF) to solve the above problems. The main of the system is to use the Latent Semantic Indexing (LSI), K-means and K-NN in Machine Learning and combine the Semantic Web, and to analyze Big Data based on cloud computing. Collect articles related to long-term care and divide them into words through Jieba. Matrix Market Format is used to transform words into matrix vectors, and TF-IDF is used to calculate the weights of words. Then LSI module is established to find out the hidden association between words, and then K-means algorithm is used to cluster the words. This research constructs a Long-Term Care Application Platform (LCAP), collects the user's problems about Long-Term 2.0 through LCAP, inputs them to the built LSI module, and classifies the problems by through K-NN algorithm. Finally, find out the matching articles through the Cosine Similarity to reply to the user. In addition, the user information collected by LCAP and the long-term care sites in Open Data are integrated into the long-term care sites and services recommended by Semantic Web. Due to the huge amount of data accumulated over the years, Spark is used to integrate Machine Learning and Semantic Web into cloud computing to improve the speed, and the K-value settings of Spark in LSI, K-means and cloud performance tests under different data volumes are compared. In this study, the accuracy and satisfaction of the survey are evaluated systematically. According to the results, LSI and K-means can meet the needs of the system at K=300, and the total satisfaction score of 5 is 4.15, which verifies the feasibility of ILKKSCF.