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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.
631

A New Fuzzy Based Stability Index Using Predictive Vehicle Modeling and GPS Data

Duprey, Benjamin Lawrence Blake 17 June 2009 (has links)
The use of global positioning systems, or GPS, as a means of logistical organization for fleet vehicles has become more widespread in recent years. The system has the ability to track vehicle location, report on diagnostic trouble codes, and keep tabs on maintenance schedules. This helps to improve the safety and productivity of the vehicles and their operators. Additionally, the increasing use of yaw and roll stability control in commercial trucks has contributed to an increased level of safety for truck drivers. However, these systems require the vehicle to begin a yaw or roll event before they assist in maintaining control. This thesis presents a new method for utilizing the GPS signal in conjunction with a new fuzzy logic-based stability index, the Total Safety Margin (TSM), to create a superior active safety system. This thesis consists of four main components: An overview of GPS technology is presented with coverage of several automotive-based applications. The proposed implementation of GPS in the new Hardware-in-the-Loop (HIL) driving simulator under development at the Virginia Tech Center for Vehicle Systems and Safety (CVeSS) is presented. The three degree-of-freedom (3DOF), linear, single track equation set used in the Matlab simulations is derived from first principles. Matlab and TruckSim 7® simulations are performed for five vehicle masses and three forward velocities in a ramp-steer maneuver. Using fuzzy logic to develop the control rules for the Total Safety Margin (TSM), TSM matrices are built for both the Matlab and TruckSim 7® results based on these testing conditions. By comparing these TSM matrices it is shown that the two simulation methods yield similar results. A discussion of the development and implementation of the aforementioned HIL driving simulator is presented, specifically the steering subsystem. Using Matlab/Simulink, dSPACE ControlDesk, and CarSim RT® software it is shown that the steering module is capable of steering the CarSim RT® simulation vehicle accurately within the physical range of the steering sensor used. / Master of Science
632

Performance evaluation of low-cost GPS machine guidance systems for livestock production forage and pasture management applications

Wright, Conner Childress 10 May 2024 (has links) (PDF)
Global Positioning System (GPS) machine guidance aids in the precise navigation and piloting of farm machinery and serves to boost productivity and optimize farm operations. Characterization of low-cost GPS guidance systems for livestock production operations is necessary for return on investment (ROI) decision making. The objective of this research is to characterize the accuracy of four commercially available low-cost ($985 - $4,200) wide area augmentation system (WAAS) corrected GPS guidance systems. Testing procedures were designed in accordance with the ASABE/ISO standard 12188-2 for testing of satellite-based guidance systems during straight line travel. The vehicles lateral deviation of a planned path, characterized as cross-track error (XTE), was evaluated for short-term and long-term guidance for each system at speeds of 4.8, 9.6, and 14.5 kph (3, 6, and 9 mph).
633

Experimental Evaluation of the Dynamic Performance Benefits of Roll Stability Control Systems on A-train Doubles

Kim, Andrew Eundong 09 February 2018 (has links)
The ride stability of an A-train 28-foot double tractor trailer when outfitted with different Roll Stability Control (RSC) systems with the same payload and suspension configurations is studied experimentally for various dynamic maneuvers. The primary goal of the study is to determine the effect of different commercially-available RSC systems on the extent of improvements they offer for increasing roll stability of commercial vehicles with double trailers, when subjected to limit-steering maneuvers that can rise during highway driving. A semitruck and two 28-foot trailers are modified for enduring the forces and moments that can result during testing. A load structure is used for placing the ballast loads within the trailers at a suitable height for duplicating the CG height of the trailers during their commercial use. Outriggers and jackknifing arresting mechanisms are used to prevent vehicle damage and ensure safety during the tests. The test vehicle is equipped with multiple sensors and cameras for the necessary measurements and observations. The analog and video data are time-synced for correlating the measurements with visual observation of the test vehicle dynamics in post-processing. An extensive number of tests are conducted at the Michelin Laurens Proving Grounds (MLPG) in Laurens, SC. The tests include evaluating each RSC system with different maneuvers and speeds until a rollover occurs or the vehicle is deemed to be unstable. The maneuvers that are used for the tests include: double lane change, sine-with-dwell, J-turn, and ramp steer maneuver. Both a steering robot and subjective driver are used for the tests. The test data are analyzed and the results are used to compare the three RSC systems with each other, and with trailers without RSC. The test results indicate that all three RSC systems are able to improve the speed at which rollover occurs, with a varying degree. For two of the systems, the rollover speed gained, when compared with trailers without RSC, is marginal. For one of the systems, there are more significant speed gains. Since most RSC systems are tuned for a conventional tractor-trailer, additional testing with some of the systems would be necessary to enable the manufacturers to better fine-tune the RSC control scheme to the dynamics of double trailers. / MS / The safety of driven semi-trailer trucks towing two trailers is analyzed in a study created to examine the behavior of the vehicle and its units during high speed, high maneuvering circumstances. The rolling over of a specific test truck is studied to study the ability of a common large vehicle to succeed in evasive or emergency maneuvers. Focus on the rolling over of a truck is placed in this project, as large freight vehicle rollovers are among the most popular and most dangerous type of accidents on highways today. A semi-trailer truck with two trailers, or double trailer vehicle, is instrumented with sensors and cameras to study several different characteristics associated with vehicle operation and conditions that incite rollover. The behavior of a double trailer vehicle is complicated due to the additional rotation joint between the adjacent trailers, where typical semi-trailer trucks (18-wheelers) only incorporate one: between the towing tractor and the towed trailer. Commercially available electronic appliances called Roll Stability Control (RSC) systems were designed to automatically control and apply the vehicle brakes under rollover conditions, and are installed and used individually to evaluate any improvements on the test vehicle’s ability to stay upright. Information regarding RSC system operation can be found. All vehicle testing is completed at a professional vehicle testing location in Laurens, SC and the same four test maneuvers are used to determine the effectiveness of each of the five RSC systems tested using data collected with the instrumented sensors. Different types of RSC systems exist due to different manners of operation, and are discussed in this document and analyzed. This project develops the conclusion that the five systems used during testing all improve vehicle stability, but provide differing results in doing so, largely due to their different operations. Therefore, commercially available RSC systems are proven to work differently and provide different results. Recommendations for further testing of RSC systems is provided. Although no recommendations are made regarding the tested RSC systems, the collected data show large, double trailer freight vehicles are more stable when using any of the tested commercially available RSC systems, especially during evasive maneuvering or emergency situations. These findings can bring immediate improvements to large freight vehicle operation and safety.
634

Eyetracking: estudio experimental del diseño de noticias en smartphones. El caso de El País Digital

Fortanet, Christian 28 June 2017 (has links)
A través de un estudio experimental con eyetrack, descubrimos los patrones de navegación visual en smartphones a la hora de consumir información en un diario digital. El caso que hemos llevado a estudio es el de El País Digital. Sobre él hemos realizado los ensayos con eyetrack, obteniendo las métricas necesarias para definir los comportamientos visuales comunes de los usuarios al navegar por la portada digital de este diario en teléfonos móviles.
635

Hur tvätt påverkar stickade elektriska ledningsbanor : En studie om korrelation mellan resistans, kontaktimpedans och böjstyvhet efter tvätt / The impact of laundry on knitted conductive tracks

Bergström, Malva Cerne January 2024 (has links)
Smarta textilier och e-textilier har, sedan de först började forskas på, haft ett potentiellt användningsområde inom sjukvården, för att användas inom långtidsövervakning av sjuka. Det största hindret som har upptäckts är, förutom att det finns vissa svårigheter med stabiliteten på signalerna från textilierna och att signalerna kan störas av brus, är att de har varit svåra att tvätta. De elektriskt ledande materialen har antagits förstörda av värmen, kemikalierna och det mekaniska arbetet från tvätten. Den här studien fokuserar på hur ledningsbanorna reagerar över lag på tvätt, och om det finns något samband mellan de olika mätmetoderna. Denna rapport testar två olika bindningar för att tillverka en stickad elektrisk ledningsbana, där en ledningsbana ligger exponerad och en ligger isolerad i bakgrundstyget. Flera olika bredder på ledningsbanan tillverkas för att undersöka om det finns någon skillnad mellan dem. Genom att testa resistansen på ledningsbanan, kontaktimpedansen mellan hud och elektrod, och böjstyvheten på fibrerna från det ledande garnet med hjälp av en FAVIMAT+ från TexTechno innan någon tvätt hade utförts, och sedan var femte tvätt upp till 30 tvättar, kan förändringen följas över en längre tid. Med de resultat som samlades in utfördes en ANOVA för varje mätmetod. Sedan utfördes flera korrelationstester, däribland SpearmanRho tester och även ett program för att anpassa en kurva till mätvärdena användes. De resultat som studien kom fram till pekar på att det inte finns något samband mellan ökningen av resistans och ökningen av kontaktimpedans. Resultaten från böjstyvheten var för brusiga för att några slutsatser skulle kunna dras. Det visar sig även att en bredare ledningsbana, och den bindning som isolerade ledningsbanan presterade bättre och hade en mindre ökning över tid än vad de smalare och exponerade ledningsbanorna hade. / Smart textiles and e-textiles have since they first started being researched had a potential to be used in the medical field to monitor sick people over a longer time. The biggest obstacle for the implementation of the smart textiles, except for the difficulty in getting a stable and clean signal, is the conductive yarns inability to handle being washed. The conductive yarn is thought to lose its conductivity due to the heat, chemicals and mechanical work it is exposed to during the wash. The focus of this study is how the conductive tracks react to washing, and if there is any correlation between the different methods of measuring. This report will test two different patterns for creating a knitted conductive track, one where the track will be exposed on the surface of the fabric, and one where it will be isolated between layers of the fabric. Different widths of the track will be tested to see if there is any difference between them. By measuring the resistance of the conductive track, the contact impedance between the skin and electrode and the bending stiffness of the fibers of the conductive yarn before any washes had been carried out, and then after every fifth wash, up to 30 washes, it was possible to track the changes over a longer period. With the results that were collected, an ANOVA was carried out for each of the testing methods. Thereafter several correlation tests were carried out, among others a SpearmanRho and a program that tried to fit a curve to the data points. The results that the study concluded were that there was no correlation between the increase in resistance and the increase of the contact impedance. The results from the bending stiffness were too inconclusive for any conclusions to be made. It also showed that a wider track and the pattern that isolated the track performed better than the thinner tracks and the pattern that exposed the track. The wider isolated track had lower increase of resistance over time that the thin exposed tracks had.
636

A Novel Approach to the Determination of Time- and Fatigue-Dependent Efficiency during Maximal Cycling Sprints

Dunst, Anna Katharina, Hesse, Clemens, Ueberschär, Olaf, Holmberg, Hans-Christer 21 February 2025 (has links)
Background: During maximal cycling sprints, efficiency (η) is determined by the fiber composition of the muscles activated and cadence-dependent power output. To date, due to methodological limitations, it has only been possible to calculate gross efficiency (i.e., the ratio of total mechanical to total metabolic work) in vivo without assessing the impact of cadence and changes during exercise. Eliminating the impact of cadence provides optimal efficiency (ηopt), which can be modeled as a function of time. Here, we explain this concept, demonstrate its calculation, and compare the values obtained to actual data. Furthermore, we hypothesize that the time course of maximal power output (Pmax) reflects time-dependent changes in ηopt. Methods: Twelve elite track cyclists performed four maximal sprints (3, 8, 12, 60 s) and a maximal-pedaling test on a cycle ergometer. Crank force and cadence were monitored continuously to determine fatigue-free force-velocity profiles (F/v) and fatigue-induced changes in Pmax. Respiratory gases were measured during and for 30 min post-exercise. Prior to and following each sprint, lactate in capillary blood was determined to calculate net blood lactate accumulation (ΔBLC). Lactic and alactic energy production were estimated from ΔBLC and the fast component of excess post-exercise oxygen consumption. Aerobic energy production was determined from oxygen uptake during exercise. Metabolic power (MP) was derived from total metabolic energy (WTOT). ηopt was calculated as Pmax divided by MP. Temporal changes in Pmax, WTOT, and ηopt were analyzed by non-linear regression. Results: All models showed excellent quality (R2 > 0.982) and allowed accurate recalculation of time-specific power output and gross efficiency (R2 > 0.986). The time-constant for Pmax(t) (τP) was closely correlated with that of ηopt (τη; r = 0.998, p < 0.001). Estimating efficiency using τP for τη led to a 0.88 ± 0.35% error. Conclusions: Although efficiency depends on pedal force and cadence, the latter influence can be eliminated by ηopt(t) using a mono-exponential equation whose time constant can be estimated from Pmax(t).
637

Characteristic errors in 120-H tropical cyclone track forecasts in the western North Pacific

Kehoe, Ryan M. 03 1900 (has links)
Approved for public release, distribution is unlimited / occurring most frequently. For the 217 large-error cases due to midlatitude influences, the most frequent error mechanisms were E-DCI (midlatitude), excessive response to vertical wind shear, excessive midlatitude cyclogenesis (E-MCG), insufficient midlatitude cyclogenesis (I-MCG), excessive midlatitude cyclolysis (E-MCL) and excessive midlatitude anticyclogenesis (E-MAG), which accounted for 68% of all large errors occurring in both NOGAPS and GFDN. Characteristics and symptoms of the erroneous forecast tracks and model fields are documented and illustrative case studies are presented. Proper identification and removal of the track forecast displaying an error mechanism could form a selective consensus that will be more accurate than a non-selective consensus. / Captain, United States Air Force
638

Architektonická studie cyklistického stadionu /dráhy/ Favorit Brno /na volné ploše v Brně Komárově/. / Architectural study of the cycling stadium / runway / Favorit Brno / on the open space in.

Dvořáková, Šárka January 2018 (has links)
A specialized project of „Architectural study of modification of the bicycle stadium Favorit Brno in the BVV area and urban design of the Hněvkovský sports complex in Komárov“ preceded the diploma thesis. The aim of the project was preparation of the area for cycling stadium with all the necessary facilities and functional connections. The diploma thesis develops a previous project and elaborates the compound of the cycling stadium in a form of a study. The building should recpect to the current demands of this sport, such as a closed roof of the building, siberian pine track material and a 250-meter track length. The building will be situated in the area adjacent to the current biker complex in Brno Komárov.
639

Favorit Brno / cyklistický stadion - bikrosová dráha / - architektonická studie - design / Favorite Brno / cycling / track stadium bikrosová architectural study design

Horčičková, Anastázie January 2019 (has links)
The aim of the diploma thesis is the architectural design of the stadium for track cycling. It deals with a covered hall, which is located in the area of Komárov on the territory of the sports resort Hněvkovského. The urban design ofthe territory is elaborated simultaneously with the study of the hall. The resort offers a wide range of sport fields for recreational as well as top athletes, and the new velodrome hall should dominate the entire area. The buildingprovides background for the important cycling club TJ Favorit Brno. It also responds to the current requirements of track cycling and thus enables the organization of international races.
640

Terminál VHD Nemocnice – Bohunice v Brně s úvraťovou konečnou stanicí tramvaje / Nemocnice – Bohunice public transport hub in Brno with settting – back track tramway terminus

Vaculíková, Barbora January 2013 (has links)
In my master thesis I deal with a design reconstruction of the current public transport terminus of Nemocnice - Bohunice. Terminus layout includes transfering the tramway line from Osová stop to the hub, the new tramway stop is a setting-back track. There is preserved the utilization of hub by existing city and regional lines of buses and troley buses and newly established regional bus lines (401,402,403,404) and also the entrance to the Bohunice hospital parking in the design. This design provides a safe flow of passengers and pedestrians and their safe road crossing.

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