• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 394
  • 75
  • 49
  • 39
  • 34
  • 29
  • 19
  • 12
  • 8
  • 4
  • 3
  • 3
  • 3
  • 3
  • 2
  • Tagged with
  • 901
  • 140
  • 139
  • 126
  • 79
  • 75
  • 67
  • 64
  • 63
  • 61
  • 59
  • 58
  • 56
  • 54
  • 54
  • 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.
511

Guidance for transport planning and policymaking in the face of an uncertain future

Lyons, Glenn, Davidson, Cody 18 November 2020 (has links)
Uncertainty of outcome is widely recognised as a concern facing decision-makers and their advisors. In a number of spheres of policy, it appears uncertainty has intensified in the face of globalisation, economic instability, climate change, technological innovation and changing consumer preferences. How can planners and policymakers plan for an uncertain future? There is growing interest in, and use of, techniques that can help decision-making processes where deep uncertainty is involved. This paper is based upon one of the most recent international examples of a foresight exercise employed to examine uncertainty – specifically that which concerns uncertainty over the nature and extent of future demand for car travel. The principal focus of the paper is on the insights and guidance this examination of uncertainty brings forth for transport planning and policymaking. To accommodate deep uncertainty requires a flexible and open approach in terms of how policy and investment possibilities are formulated and judged. The paper argues for a focus upon the Triple Access System of spatial proximity, physical mobility and digital connectivity as a framework for policy and investment decisions that can harness flexibility and resilience. Uncertainty becomes an opportunity for decision-makers with the realisation that they are shaping the future rather than (only) responding to a predicted future. The paper outlines two forms of policymaking pathway: regime-compliant (in which adherence to trends and the nature of the world we have known pushes policy) and regime-testing (in which the nature of the world as we have known it is brought into question and vision pulls policy decisions). Stronger orientation towards regime-testing to assist in managing an uncertain future is advocated.
512

Study on Communication System From the Perspective of Improving Signal-to-Noise Ratio / 通信システムにおけるSN比の改善に関する研究

Tsuda, Hirofumi 25 March 2019 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(情報学) / 甲第21915号 / 情博第698号 / 新制||情||120(附属図書館) / 京都大学大学院情報学研究科数理工学専攻 / (主査)教授 梅野 健, 教授 山下 信雄, 教授 守倉 正博 / 学位規則第4条第1項該当 / Doctor of Informatics / Kyoto University / DFAM
513

Towards the Integration of Low-cost Sensors into Smart Building Systems for Indoor Air Quality Purposes

Young, Matthew W. January 2019 (has links)
No description available.
514

Techno-Economic Optimization and Control of Hybrid Energy Systems

Calmered, Louise, Nyberg, Tanja January 2023 (has links)
The increasing demand for renewable energy sources to meet climate targets and reduce carbon emissions poses challenges to the power grid due to their intermittent nature. One potential solution to maintain grid stability is by implementing Hybrid Energy Systems (HESs) that incorporate a Battery Energy Storage System (BESS). To achieve the most favorable outcome in terms of both technical feasibility and profitability of a BESS, it is essential to employ models for simulating and optimizing the control of system components. This thesis focuses on the analysis of energy and revenue streams in a HES consisting of a BESS, photovoltaics (PVs), and an energy load including a fast charging station for electric vehicles (EVs). The objective is to optimize the system based on revenue generation by comparing the control techniques of peak shaving, energy arbitrage, and the integration of ancillary services within the Swedish energy market. The research questions explore the optimal utilization of the BESS and assess the impact of the different control techniques. A model is created in Python with the package CasADi where data from an ongoing installation of a HES in southern Sweden is combined with data from literature research. The model includes an objective function that minimizes the total cost of power from the grid based on the day-ahead price, battery degradation, and monthly peak power.  To answer the research questions, four different scenarios are simulated. The first scenario is a base for comparison, the second one focuses on peak shaving and energy arbitrage, the third on participation in the ancillary service FCR-D upwards regulation, and the last one is a combination of peak shaving, energy arbitrage, and the ancillary service FCR-D. The results show that the remuneration from the ancillary service FCR-D is comparably much higher than the revenues generated from peak shaving and energy arbitrage, providing more than 500% of revenue compared to the same system but without a BESS. The scenario with peak shaving and energy arbitrage shows an increase in revenue of 29% but with more cycling of the battery which could cause losses in performance in the long term. To validate the results, sensitivity analyses are conducted by evaluating weighting in the objective function, implementing Model Predictive Control (MPC), and reviewing price variations.  In conclusion, efficient control techniques can enhance system performance, minimize losses, and ensure optimal utilization of different energy sources, leading to improved feasibility and profitability. The optimal usage of a BESS involves finding a balance between maximizing revenue generation and minimizing battery degradation. This can be achieved through control strategies that optimize the charging and discharging patterns of the BESS based on electricity price signals, demand patterns, and battery health considerations.
515

The effect of the shoe sole on Plantar Pressure distribution / Påverkan av skosulans utformning på fotens tryckfördelning

Ejimadu, Geraldine January 2020 (has links)
Patients affected by Diabetes Mellitus have reduced tactile sensitivity and atrophy of the small muscles in the foot, resulting in high-pressure points that may remain unnoticed. The increased pressure can cause micro-trauma leading to wounds. Because of the Diabetes Mellitus, DFUs do not heal easily. Up to 25% of them will develop diabetic foot ulcers (DFU), and 25% of DFUs that do not heal ultimately result in amputation. This Master Thesis will describe and gather results of a newly acquired large international collaborative EU project (EIT Health 2020-2022) between three universities and three companies across Europe. This collaborative group will be the first to tackle the Diabetic Foot Ulcers problem preventatively with an innovative shoe concept, with seven different apex settings, which can be easily modified to avoid ulcerations in different areas of the foot. As an initial pilot, this master thesis project focuses on the analysis of the plantar pressure distribution by using the innovative shoes DR Comfort based on the adjustable rocker profiles, used as a prototype for the prevention of the Diabetic Foot Ulcer (DFU) formation in patients affected by Diabetes. This project captures the motion data of healthy people with different shoe soles while walking at different levels of speed and assess the values of the peak plantar pressure, with the use of the Pedar-X, a measuring system device for the in-shoe plantar pressure. The evaluation of the adjustable rocker profiles is made through the calculation and analysis of the significant differences and p-values in peak plantar pressure, as well as the analysis of the Mean Plantar Pressure (MMP). The results of this study show a reduction (although not pronounced) of the areas that are more affected by DFU. This study cannot be generalized to diabetic patients since ethical approval has not yet been received. / Patienter med DM har minskad taktil känslighet och atrofi i de små musklerna i foten, vilket resulterar i högatryckpunkter som kan för bli obemärkta. Det ökade trycket kan orsaka mikrotrauma som leder till sår. På grund av Diabetes Mellitus, läker inte DFU lätt. Upp till 25% av dem kommer att utveckla diabetiska fotsår (DFU), och 25% av DFU: er som inte läker leder slutligen till amputation. Detta examensarbete kommer att beskriva och samla resultat från ett nyförvärvat stort internationellt EU-projekt (EIT Health 2020-2022) mellan tre universitet och tre företag i hela Europa. Denna samarbetsgrupp kommer att vara den första att förebygga problemet med diabetiska fotsår med ett innovativt skokoncept diabetiska fotsår med ett innovativt skokoncept. De kommer utföras med sju olika inställningar som lätt kan modifieras för att undvika sår på olika områden i foten. Som en första pilot fokuserar detta examensarbete på analys av plantartryckfördelning genom att använda de innovativa DR Comfort-skorna baserade på de justerbara ”rocker”-profilerna, som används som en prototyp för att förebygga bildningen av Diabetic Foot Ulcer (DFU) hos patienter som drabbats av Diabetes. Den här avhandlingen fångar rörelsen hos friska personer med olika skosulor medan de går i olika hastighet och analyserar värdena för det maximala plantartrycket med användning av pedar-x. Pedar-x är en mätanordning för plantorns tryck i skon. Utvärderingen av de justerbara ”rocker”-profilerna gjordes genom beräkning och analys av de signifikanta skillnaderna i top plantartrycket samt analysen av plantartryckets maximala medelvärde (MMP). Resultaten av denna studie visar en minskning (även om den inte betydlig) av de områden som mest drabbats av DFU. Denna studie kan inte generaliseras till diabetespatienter eftersom etiskt godkännande ännu saknas.
516

Rapid Grip Strength and Muscle Activity as Predictors of Reaction Time

Rodriguez, Gabriela 01 January 2021 (has links)
INTRODUCTION: Reaction time may be broadly defined as the time between stimulus presentation and a response. Analysis of reaction time in terms of rate of force development (RFD), peak force, and surface electromyography (EMG) may help bridge the gaps in knowledge pertaining to the neuromuscular system's role in reaction time. The purpose of the present study was to identify predictors of reaction time using digital hand grip dynamometry and EMG. It was hypothesized that RFD and rate of EMG rise (RER) at the onset of a contraction would correlate with reaction time. METHODS: For grip testing, participants were instructed to squeeze a handheld dynamometer with the right hand "…as hard and fast as possible" for 5 seconds upon hearing a "beep" from the computer. A total of 5 attempts were performed, with 1-minute rest periods. Bipolar surface EMG signals were detected from the right first dorsal interosseous (FDI) and flexor carpi radialis (FCR) muscles throughout grip testing. Bivariate correlations (Pearson r) were used to examine the statistical associations. The 95% confidence interval (CI) for each Pearson r was also computed. An alpha level of p ≤ 0.05 was used to reject the null hypothesis. RESULTS: Significant correlations were observed between reaction time and all other measures of grip force (r = -0.507 to -0.557, p= 0.016 to 0.042), except for time until peak force (r = 0.029, p = 0.915). As FDI EMG amplitude increased reaction time decreased (r = -0.664, p = .005). CONCLUSION: Many of the grip force variables were significantly associated with reaction time. Peak force and rapid force variables showed significant correlations with reaction time. While no significant correlations for any of the FDI RER or FCR variables were found, EMG amplitude from the FDI presented the strongest bivariate correlation. As FDI EMG amplitude, peak force, and rapid force variables increased reaction time decreased. These findings give some insight into the neuromuscular system's role in hand grip tasks and help broaden the current understanding of variables that may be used to assess or improve reaction time in the clinical setting.
517

INFLUENCE OF PRESSURE ON FAST DYNAMICS IN POLYMERS

Begen, Burak January 2007 (has links)
No description available.
518

MALDI-TOF MS Data Processing Using Wavelets, Splines and Clustering Techniques.

Chen, Shuo 18 December 2004 (has links) (PDF)
Mass Spectrometry, especially matrix assisted laser desorption/ionization (MALDI) time of flight (TOF), is emerging as a leading technique in the proteomics revolution. It can be used to find disease-related protein patterns in mixtures of proteins derived from easily obtained samples. In this paper, a novel algorithm for MALDI-TOF MS data processing is developed. The software design includes the application of splines for data smoothing and baseline correction, wavelets for adaptive denoising, multivariable statistics techniques such as clustering analysis, and signal processing techniques to evaluate the complicated biological signals. A MatLab implementation shows the processing steps consecutively including step-interval unification, adaptive wavelet denoising, baseline correction, normalization, and peak detection and alignment for biomarker discovery.
519

An Investigation into the Mechanisms of Formation of the Hard Zone in FSW X65

Allred, Jacob D. 13 November 2013 (has links) (PDF)
Friction stir welding (FSW) of HSLA steel commonly produces a hard zone (HZ) on the advancing side (AS) of the weld. Despite its detrimental effects on weld toughness, the mechanisms of its formation have not been thoroughly investigated and are not well understood. This paper investigates the various mechanisms in FSW believed to affect the weld HZ, namely: strain, strain-rate, peak temperature and cooling rate. Gleeble tests indicate that strain and strain rate have negligible effects on weld HZ with cooling rate and peak temperature as dominant effects. Jominy tests resulted in cooling rate having 270% greater influence than peak temperature on the formation of lath ferrite microstructures similar to what is observed in the HZ of FSW X65. Comparing weld HZ microstructures to Jominy tests, it is estimated that cooling rates on the AS of the weld are at least 150°C/s higher than the retreating side. Reducing the cooling rate on the AS will likely lead to an improved microstructure at the weld HZ.
520

Microchip Thermal Gradient Gas Chromatography

Wang, Anzi 01 December 2014 (has links) (PDF)
Although the airbath oven is a reliable heating method for gas chromatography (GC), resistive heating is needed for higher analytical throughput and on-site chemical analysis because of size, heating rate and power requirements. In the last thirty years, a variety of resistive heating methods were developed and implemented for both benchtop and portable GC systems. Although fast heating rates and low power consumption have been achieved, losses in column efficiency and resolution, complex construction processes and difficulties experienced in recovering damaged columns have also become problematic for routine use of resistively heated columns. To solve these problems, a new resistively heated column technique, which uses metal columns and self-insulated heating wires, was developed for capillary gas chromatography. With this method, the total thermal mass was significantly less than in commercial column assemblies. Temperature-programming using resistive heating was at least 10 times faster than with a conventional oven, while only consuming 1—5% of the power that an oven would use. Cooling a column from 350 °C to 25 °C with an air fan only required 1.5 min. Losses in column efficiency and peak capacity were negligible when compared to oven heating. The major trade-off was slightly worse run-to-run retention time deviations, which were still acceptable for most GC analyses. The resistively heated column bundle is highly suitable for fast GC separations and portable GC instruments. Fabrication technologies for microelectromechanical systems (MEMS) allow miniaturization of conventional benchtop GC to portable, microfabricated GC (µGC) devices, which have great potential for on-site chemical analysis and remote sensing. The separation performance of µGC systems, however, has not been on par with conventional GC. Column efficiency, peak symmetry and resolution are often compromised by column defects and non-ideal injections. The relatively low performance of µGC devices has impeded their further commercialization and broader application. This problem can be resolved by incorporating thermal gradient GC (TGGC) into microcolumns. Negative thermal gradients reduce the on-column peak width when compared to temperature-programmed GC (TPGC) separations. This unique focusing effect can overcome many of the shortcomings inherent in µGC analyses. In this dissertation research, the separation performance of µGC columns was improved by using thermal gradient heating with simple set-ups. The analysis time was ~20% shorter for TGGC separations than for TPGC when wide injections were performed. Up to 50% reduction in peak tailing was observed for polar analytes, which significantly improved their resolution. The signal-to-noise ratios (S/N) of late-eluting peaks were increased by 3 to 4 fold. These results indicate that TGGC is a useful tool for bridging the performance gap between µGC and benchtop GC.

Page generated in 0.0331 seconds