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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
161

RAM-minnets kontaminering vid tillämpning av forensiska verktyg

Johansson, Christian, Nilsson, Robin January 2011 (has links)
Denna rapport behandlar ett specifikt område inom IT-forensik och informationssäkerhet. Då en berörd part behöver agera i ett skarpt läge, kan kunskaperna om volatilt minne vara avgörande. I takt med att IT-brott har ökat dramatiskt, har det också bidragit till en enorm utveckling inom de forensiska ramarna. IT-forensikerns handlingar är av avgörande karaktär då minnet förändras kontinuerligt, därför eftersträvas minimala förändringar på systemet. Ett datorsystem är utrustat med ett fysiskt minne vars syfte är att temporärt lagra information då det är aktivt. Detta minne kan vara en rik informationskälla ur ett forensiskt perspektiv. Volatilt minne är uppbyggt av binärkod som går att analysera med hjälp av verktyg. Idag finns det ett stort utbud av verktyg för allmänheten och myndigheter, därför begränsas rapporten med inriktning mot kommersiella metoder. För att effektivisera det praktiska utförandet, tillämpas virtualisering som underlättar påvisning av konsistent datautvinning. Vid experimenterande av volatilt minne erhölls framgångsrika resultat där det gick att fastställa förändringar i minnesallokeringen. Då ett program exekveras, resulterar det i märkbara förändringar som går att urskilja i det fysiska minnet. När verktyget sedan har utfört sina givna instruktioner, går det att tolka den procentuella skillnaden mellan minnes-dumparna. Detta bidrog till de förutbestämda målen. Det fysiska minnet är ett relativt nytt och outforskat tekniskt område. Valmöjligheten för en minnesutvinning kan innefatta allt från hårdvaru- till mjukvarulösningar där tyngden på denna rapport baseras på mjukvarulösning. Alla IT-forensiker bör få upp ögonen för denna informationstillgång som kan vara nyckeln till framgång under live-respons.
162

Postup opravy beranu lisu / The repair procedure of the press frame

Švarc, Lukáš January 2018 (has links)
The diploma thesis is dealing with the repair procedure of the cracked ram of the press – machine parts made from gray cast iron by casting. The ram is a part of the repaired forming press LET 160. The presented work contains an overview and analysis of the technologies of repair of cast iron by welding. On the basis of the theoretical part is designed the procedure of repairing. The aim of the experimental tests is selecting the most suitable additional materiál and verifying the proposed welding process. The welding method was selected by a low preheating manual metal arc. All the pWPS were prepared for the welding of all test specimens. Experimental samples were subjected to visual, macroscopic, microscopic analysis and hardness measurement. Based on the results of the experiments was suggested a welding repair procedure with a pWPS.
163

Stanovení pracovního rozsahu a účinnosti vodního trkače / Determination of the working range and efficiency of the water hammer pump

Růžička, Jakub January 2019 (has links)
This thesis focuses on setting the range and efficiency of a water ram pump through experimental measurements in a laboratory. The measurements were carried out on three different constructions of water ram pump, each of the designed and assembled by the author of this thesis himself, to find out whether the weight on the pulsating valve has an influence on the water ram pump efficiency. Further on this thesis aims at the comparison of up to now methods of water transport arrangement used at a summer camp and the usage of the water ram pump and its advantages. The principal of water ram pump originates in hydraulic impact that is being precisely described in a great detail as well. On of the chapters even includes the placement manual for the water ram pump and its overall assembly and connexion. Because the presence of floating debris is inevitable, this thesis also deals with the possibility to solve the incoming water impurities by adding an inflow gating to prevent such problem. This inflow gating has only been designed in a Flow 3D programme to introduce the idea and functions.
164

Konstrukce cestovní nabíječky pro mobilní telefon / Construction of portable charger for mobile phone

Stejskal, Lukáš January 2011 (has links)
In this thesis suggest the involvement of appropriate driver for mobile phone travel charger. The work is a treatise on the available accumulators, which can be used as a source for the proposed power converter.
165

Hydraulicko-elektrický systém zajišťující paralelitu chodu beranu vůči stolní desce hydraulického lisu / Hydraulic - electric system for parallel run of the ram in the face of table board of hydraulic press

Ošlejšek, Jan January 2008 (has links)
The aim of the diploma thesis is design construction and calculation of mechanism for parallel run of ram and adjusting position of ram in the face of table board of vertical hydraulic press. First part of thesis is about design calculation of vertical hydraulic press ram. Second part focuses on design calculation of ram and hydraulic cylinders. Third part solves design and construction of positioning hydraulic–electric system. Final fourth part analyses press construction from aspects of safeness, riskiness and economical factors.
166

Konstrukční návrh portálové CNC frézky / Design of gantry CNC milling machine

Ludva, Jan January 2016 (has links)
This master’s thesis deals with a design of a portal CNC milling machine. The thesis contains a description of milling machine’s single types, analysis of Czech and foreign market and analysis of basic milling machine’s groups. The work includes calculating of cutting forces and moments of a chosen tool, choice of spindle and design of axe’s drive systems. The thesis also includes 3D model of the chosen variant, it’s by a method of final elements and finally drawing documentation.
167

Accelerated long range electrostatics computations on single and multiple FPGAs

Ducimo, Anthony 22 January 2021 (has links)
Classical Molecular Dynamics simulation (MD) models the interactions of thousands to millions of particles through the iterative application of basic Physics. MD is one of the core methods in High Performance Computing (HPC). While MD is critical to many high-profile applications, e.g. drug discovery and design, it suffers from the strong scaling problem, that is, while large computer systems can efficiently model large ensembles of particles, it is extremely challenging for {\it any} computer system to increase the timescale, even for small ensembles. This strong scaling problem can be mitigated with low-latency, direct communication. Of all Commercial Off the Shelf (COTS) Integrated Circuits (ICs), Field Programmable Gate Arrays (FPGAs) are the computational component uniquely applicable here: they have unmatched parallel communication capability both within the chip and externally to couple clusters of FPGAs. This thesis focuses on the acceleration of the long range (LR) force, the part of MD most difficult to scale, by using FPGAs. This thesis first optimizes LR acceleration on a single-FPGA to eliminate the amount of on-chip communication required to complete a single LR computation iteration while maintaining as much parallelism as possible. This is achieved by designing around application specific memory architectures. Doing so introduces data movement issues overcome by pipelined, toroidal-shift multiplexing (MUXing) and pipelined staggering of memory access subsets. This design is then evaluated comprehensively and comparatively, deriving equations for performance and resource consumption and drawing metrics from previously developed LR hardware designs. Using this single-FPGA LR architecture as a base, FPGA network strategies to compute the LR portion of larger sized MD problems are then theorized and analyzed.
168

Novel Double-Deposited-Aluminum (DDA) Process for Improving Al Void and Refresh Characteristics of DRAM

Hong, Seok-Woo, Kang, Seung-Mo, Choi, In-Hyuk, Jung, Seung-Uk, Park, Dong-Sik, Kim, Kyoung-Ho, Choi, Yong-Jin, Lee, Tae-Woo, Lee, Haebum, Cho, In-Soo 22 July 2016 (has links)
In order to resolve the Al void formation originated from the severe stress issues in dynamic random access memory (DRAM), double-deposited-aluminum (DDA) layer process was proposed. This novel metallization process can be effectively and simply performed with the native oxide such as Al 2 O 3 between upper and lower Al metal layer by ex-situ deposition technique. We could effectively control the Al void by adapting the DDA layers with different grain structure. From this novel metallization process, we have confirmed the optimal thickness of Al barrier metal to 100Å to be free from Al voids, which makes it possible to improve the static refresh characteristics of DRAM by 17%.
169

Ultrathin CaTiO3 Capacitors: Physics and Application

Krause, Andreas 01 April 2014 (has links)
Scaling of electronic circuits from micro- to nanometer size determined the incredible development in computer technology in the last decades. In charge storage capacitors that are the largest components in dynamic random access memories (DRAM), dielectrics with higher permittivity (high-k) were needed to replace SiO2. Therefore ZrO2 has been introduced in the capacitor stack to allow sufficient capacitance in decreasing structure sizes. To improve the capacitance density per cell area, approaches with three dimensional structures were developed in device fabrication. To further enable scaling for future generations, significant efforts to replace ZrO2 as high-k dielectric have been undertaken since the 1990s. In calculations, CaTiO3 has been identified as a potential replacement to allow a significant capacitance improvement. This material exhibits a significantly higher permittivity and a sufficient band gap. The scope of this thesis is therefore the preparation and detailed physical and electrical characterization of ultrathin CaTiO3 layers. The complete capacitor stacks including CaTiO3 have been prepared under ultrahigh vacuum to minimize the influence of adsorbents or contaminants at the interfaces. Various electrodes are evaluated regarding temperature stability and chemical reactance to achieve crystalline CaTiO3. An optimal electrode was found to be a stack consisting of Pt on TiN. Physical experiments confirm the excellent band gap of 4.0-4.2 eV for ultrathin CaTiO3 layers. Growth studies to achieve crystalline CaTiO3 indicate a reduction of crystallization temperature from 640°C on SiO2 to 550°C on Pt. This reduction has been investigated in detail in transmission electron microscopy measurements, revealing a local and partial epitaxial growth of (111) CaTiO3 on top of (111) Pt surfaces. This preferential growth is beneficial to the electrical performance with an increased relative permittivity of 55 with the advantage of a low leakage current comparable to that in amorphous CaTiO3 layers. A detailed electrical analysis of capacitors with amorphous and crystalline CaTiO3 reveals a relative permittivity of 30 for amorphous and an excellent value of 105 for fully crystalline CaTiO3. The permittivity exhibits a quadratic dependence with applied electric field. Crystalline CaTiO3 shows a 1-3% drop in capacitance density and permittivity at a bias voltage of 1V, which is significantly lower compared to all results for SrTiO3 capacitors measured elsewhere. A capacitance equivalent thickness (CET) below 1.0 nm with current densities 1×10−8 A/cm2 have been achieved on carbon electrodes. Finally, CETs of about 0.5 nm with leakage currents of 1 × 10−7 A/cm2 on top of Pt/TiN fulfill the 2016 DRAM requirements following the ITRS road map of 2012. / Die Verkleinerung von elektronischen Bauelementen hin zu nanometerkleinen Strukturen beschreibt die unglaubliche Entwicklung der Computertechnologie in den letzten Jahrzehnten. In Ladungsspeicherkondensatoren, den größten Komponenten in Arbeitsspeichern, wurden dafür Dielektrika benötigt, die eine deutlich höhere Permittivität als SiO2 besitzen. ZrO2 wurde als geeignetes Dielektrikum eingeführt, um eine ausreichende Kapazität bei kleiner werdenen Strukturen sicherzustellen. Zur weiteren Verbesserung der Kapazitätsdichte pro Zellfläche konnten 3D Strukturen in die Chipherstellung integriert werden. Seit den 1990ern wurden parallel bedeutende Anstrengungen unternommen, um ZrO2 als Dielektrikum durch Materialien mit noch höherer Permittivität zu ersetzen. Nach Berechnungen stellt nun CaTiO3 eine mögliche Alternative dar, die eine weitere Verbesserung der Kapazität ermöglicht. Das Material besitzt eine deutlich höhere Permittivität und eine ausreichend große Bandlücke. Diese Arbeit beschäftigt sich deshalb mit Herstellung und detaillierter physikalischer und elektrischer Charakterisierung von extrem dünnen CaTiO3 Schichten. Zusätzlich wurden diverse Elektroden bezüglich ihrer Temperaturstabilität und der chemischen Stabilität untersucht, um kristallines CaTiO3 zu herhalten. Als eine optimale Elektrode stellte sich Pt auf TiN heraus. Physikalische Experimente an extrem dünnen CaTiO3 Schichten bestätigen die Bandlücke von 4,0-4,2 eV. Wachstumsuntersuchungen an kristallinem CaTiO3 zeigen eine Reduktion der Kristallisationstemperatur von 640°C auf SiO2 zu 550°C auf Pt. Diese Reduktion wurde detailliert mittels Transmissionselektronenmikroskopie untersucht. Es konnte für einige Schichten ein partielles lokales epitaktischesWachstum von (111) CaTiO3 auf (111) Pt gemessen werden. Dieses Vorzugswachstum ist vorteilhaft für die elektrischen Eigenschaften durch eine gesteigerte Permittivität von 55 bei gleichzeitig geringem Leckstrom vergleichbar zu amorphen Schichten. Eine genaue elektrische Analyse von Kondensatoren mit amorphen und kristallinem CaTiO3 ergibt eine Permittivität von 30 für amorphe und bis zu 105 für kristalline CaTiO3 Schichten. Die Permittivität zeigt eine quadratische Abhängigheit von der angelegten Spannung. Kristallines CaTiO3 zeigt einen 1-3% Abfall der Permittivität bei 1V, der wesentlich geringer ausfällt als vergleichbare Werte für SrTiO3. Eine zu SiO2 vergleichbare Schichtdicke (CET) von unter 1,0 nm mit Stromdichten von 1×10−8 A/cm2 wurde auf Kohlenstoffsubstraten erreicht. Mit Werten von 0,5 nm bei Leckstromdichten von 1×10−7 A/cm2 auf Pt/TiN Elektroden erfüllen die CaTiO3 Kondensatoren die Anforderungen der ITRS Strategiepläne für Arbeitsspeicher ab 2016.
170

Novel Bio-inspired Aquatic Flow Sensors

Pinto, Preston Albert 23 July 2012 (has links)
Inspired by the roles of hair cells in nature, this study aims to develop and characterize two new sets of novel flow sensors. One set of sensors developed and studied in this work are flow sensors fabricated using carbon nanomaterials. These sensors are made by embedding carbon nanotubes (CNT) and carbon nanohorns (CNH) into a polymeric substrate and then tested by flowing a conductive aqueous solution over the surface of the exposed CNT and CNH. In response, a flow-dependent voltage is generated. The surface coverage and the electrical relationship between the sensor and water is investigated and the voltage measurements of sensors with different levels of resistance were tested in varying fluid velocities. In response to these fluid velocities, the least resistive sensor showed small, but detectable changes in voltages, while higher resistance sensors showed less response. In addition, plasma treatment of the carbon nanomaterial/PDMS films were conducted in order to render the PDMS on the surface hydrophilic and in turn to pull more fluid towards the carbon material. This showed to improve the sensitivity of the flow sensors. This work also builds on previous research by investigating the flow dependent electrical response of a "skin"-encapsulated artificial hair cell in an aqueous flow. An artificial cell membrane is housed in a flexible polyurethane substrate and serves as the transduction element for the artificial hair cell. Flow experiments are conducted by placing the bio-inspired sensor in a flow chamber and subjecting it to pulse-like flows. This study demonstrates that the encapsulated artificial hair cell flow sensor is capable of sensing changes in flow through a mechanoelectrical response and that its sensing capabilities may be altered by varying its surface morphology. Furthermore, the sensor's response and dynamics as a function of its surface morphology and structural properties are investigated through synchronized motion tracking of the hair with a laser vibrometer and current measurements across the artificial cell membrane. / Master of Science

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