• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 235
  • 83
  • 70
  • 26
  • 22
  • 17
  • 10
  • 10
  • 7
  • 6
  • 3
  • 3
  • 3
  • 2
  • 2
  • Tagged with
  • 564
  • 128
  • 112
  • 89
  • 83
  • 74
  • 62
  • 46
  • 38
  • 38
  • 35
  • 30
  • 30
  • 29
  • 29
  • 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.
151

Methods for improving foot motion measurement using inertial sensors

Charry, Edgar January 2010 (has links)
As a promising alternative to laboratory constrained video capture systems in studies of human movement, inertial sensors (accelerometers and gyroscopes) are recently gaining popularity. Secondary quantities such as velocity, displacement and joint angles can be calculated through integration of acceleration and angular velocities. However, it is broadly accepted that this procedure is significantly influenced by cumulative errors due to integration, arising from sensor noise, non-linearities, asymmetries, sensitivity variations and bias drifts. In this study, new methods for improving foot motion from inertial sensors are explored and assessed. / Sensor devices have been developed previously, for example, to detect postural changes that determine potential elderly fallers, and monitor a person’s gait. Recently, a gait variable known as minimum toe clearance (MTC) has been proposed to describe age-related declines in gait with better success as a predictor of falls risk. The MTC is the minimum vertical distance between the lowest point on the shoe and the ground during the mid-swing phase of the gait cycle. It is therefore of our interest to design a cost effective but accurate solution to measure toe clearance data which can then be used to identify the individuals at risk of falling. In this study, hardware, firmware and software features from off-the-shelf inertial sensors and wireless motes are evaluated and their configuration optimized for this application. A strap-down method, which consists of the minimizing of the integration drift due to cumulative errors, is evaluated off-line. Analysis revealed the necessity of band-pass filtering methods to correct systematic sensor errors that dramatically reduce the accuracy in estimating foot motion. / Cumulative errors were studied in the frequency domain, employing content of inertial sensor foot motion evaluated against a ’gold standard’ video-based device, namely the Optotrak Certus NDI. In addition, the effectiveness of applying band-pass filtering to raw inertial sensor data is assessed, under the assumption that sensor drift errors occur in the low frequency spectrum. The normalized correlation coefficient ρ of the Fast Fourier Transform (FFT) spectra corresponding to vertical toe acceleration from inertial sensors and from a video capture system as a function of digital band-pass filter parameters is compared. The Root Mean Square Error (RMSE) of the vertical toe displacement is calculated for 5 healthy subjects over a range of 4 walking speeds. The lowest RMSE and highest cross correlation achieved for the slowest walking speed of 2.5km/h was 3.06cmand 0.871 respectively, and 2.96cm and 0.952 for the fastest speed of 5.5km/h.
152

Konstruktion och utvärdering av Current Conveyors / Construction and evaluation of Current Conveyors

Jonasson, Anders January 2003 (has links)
<p>Normally the operational amplifier is used as a component in active filter design. The goal for future components in filter design is large bandwith and the use of low supply voltages. The use of current-mode instead of voltage-mode circuits gets a step closer to the required performance. A component that use current as the signal conveying part is the current conveyor. In this report a comparative study between two current conveyor structures of second generation (CCII) is performed. The most suited is later implemented and simulated using the CMOS process AMS.C035. The component is also tested in a continuous-time elliptic low-pass filter of leapfrog type. The filter does not behave as it should. However, better performance can be obtained by redesigning the current conveyor.</p>
153

The Exchange Rate Pass-through Into Domestic Manufacturing Prices During Two Inflation Regimes

Shahbazian, Roujman January 2009 (has links)
<p>In the beginning of 1990s Sweden implemented several measures in order to maintain price stability. These measures have resulted in an environment in which inflation is lower and more stable. The same development could be seen in other OECD countries. At the same time a decrease in exchange rate pass-through was noticed in many countries. This has led researchers to believe that there may be a connection, between these two phenomena. This dissertation analyzes whether there has been any change in exchange rate pass-through for manufacturing products in Sweden between the high inflation period (1977-1993) and the low inflation period (1994-2006). The result shows that there is a difference in the exchange rate pass-through between the two periods. During the low inflation period the degree of pass-through was lower than during the high inflation period.</p>
154

Pass – Througheffekten i svenska importpriser : en empirisk studie

Svensson, Anders January 2007 (has links)
<p>I den här uppsatsen har jag undersökt hur pass-through effekten har förändrats i svenska importpriser på aggregerad nivå och i sju olika industrier. Pass-through effekten definieras som den procentuella förändringen i ett pris som kan härledas till en enprocentig växelkursförändring. Jag har använt rullande regressioner på två olika modeller för att estimera förändringar över tidsperioden 1980 – 2003. Resultaten visar en nedgång i pass-through effekten i flertalet industrier både på kort och lång sikt. Men på aggregerad nivå visar resultaten att effekten inte har förändrats nämnvärt över tiden. På kort sikt visar de båda metoderna liknande resultat, men på lång sikt finns det en skillnad dem emellan. En av modellerna visar en fördröjning i den långsiktiga pass-through effekten, vilket kan förklaras med att prissättningen inte är effektiv och att det finns störningar på marknaden.</p>
155

Pass – Througheffekten i svenska importpriser : en empirisk studie

Svensson, Anders January 2007 (has links)
I den här uppsatsen har jag undersökt hur pass-through effekten har förändrats i svenska importpriser på aggregerad nivå och i sju olika industrier. Pass-through effekten definieras som den procentuella förändringen i ett pris som kan härledas till en enprocentig växelkursförändring. Jag har använt rullande regressioner på två olika modeller för att estimera förändringar över tidsperioden 1980 – 2003. Resultaten visar en nedgång i pass-through effekten i flertalet industrier både på kort och lång sikt. Men på aggregerad nivå visar resultaten att effekten inte har förändrats nämnvärt över tiden. På kort sikt visar de båda metoderna liknande resultat, men på lång sikt finns det en skillnad dem emellan. En av modellerna visar en fördröjning i den långsiktiga pass-through effekten, vilket kan förklaras med att prissättningen inte är effektiv och att det finns störningar på marknaden.
156

Non-linear Structure Of The Turkish Interest Rate Transmission Mechanism

Bozok, Ihsan 01 September 2012 (has links) (PDF)
This paper empirically analyses the interest rate transmission mechanism from money market rate to lending rate by utilizing the bank-level data in the distinction of cash, automobile, housing and corporate loans in Turkey. The main objective is to reveal the possible asymmetries of the adjustment process as well as the extent of the pass through. Empirical results indicate that mark-up value is the minimum for corporate rates on average, followed by housing, automobile and cash rates, respectively. Additionally, while large banks follow small mark-up pricing, small banks follow large mark-up pricing for corporate loans. Furthermore, a complete pass through is detected in 75 percent of the corporate loans, whereas the rates of banks that completely react to money market changes are 58 percent for cash and housing loans and 50 percent for automobile loans. We also find evidence that cash loans having high mark-up values do not adjust completely to variations in money market rate. Based on TAR and MTAR models of Enders and Siklos (2001), substantial asymmetries exist for all lending types. In general, adjustment towards the long-run equilibrium is faster when the disequilibrium or change in disequilibrium is above the threshold (upward rigidity).
157

A Geochemical Characterization of a Cold-Water Acid Rock Drainage Stream Emanating From the Zn-Pb XY-deposit, Howard's Pass, Yukon Territory, Canada

Feige, Kristen B. 08 February 2011 (has links)
An acid rock drainage (ARD) stream emanating from the Zn-Pb XY-deposit in the Yukon Territory was examined in order to evaluate the physico-chemical and geochemical processes governing the distribution of dissolved elements from the creek. The creek showed very high concentrations of metals (300 mg/L Fe, 500 mg/L Zn, 15 000 µg/L Ni, 1300 µg/L Cu and 4500 µg/L Cd), low water temperatures (1 – 12°C) and was acidic to moderately acidic (pH 3.1 – 5.0). It was found that this stream experienced a strong seasonal evolution, with increased sulphate and metal concentrations and decreased pH over the course of the summer. The mineral precipitates that formed under low pH conditions were a mixture of schwertmannite, goethite, jarosite and barite, while those that formed under moderately acidic conditions were a mixture of jurbanite, hydrobasaluminite, gibbsite and an X-ray amorphous Al-sulphate phase. Most of the mineral precipitates were of inorganic origin, although microbes may have played a role in mineral formation and trace metal sequestration in some of the precipitates. All of the mineral precipitates contained anomalous concentrations of trace elements (up to 1.5 % wt Zn) and showed a seasonal evolution in their mineralogy, both of which were determined to be a function of the pH and prevailing geochemical conditions. The geochemistry of the ARD creek draining the XY-deposit was compared to another ARD creek in the area that was likely draining shales. The two creeks were compared in order to determine if ARD geochemical characteristics can be used as a tool for the mineral exploration industry.
158

Application of Pharmacokinetic Theory to Examine Roles of Transporters and Enzymes in Intestinal and Hepatic Drug Disposition

Sun, Huadong 26 February 2009 (has links)
The interplay of transporters and enzymes and their transporter-enzyme was examined in Caco-2 cell monolayer and recirculating perfused rat liver preprations via both theoretical and experimental approaches. First, a Caco-2 catenary model that consisted of the apical, cellular, basolateral compartments and encompasses influx, efflux transporters and enzymes was shown to be superior to the single barrier approach for data interpretation on transporter- and enzyme- mediated processes. The kinetics of baicalein, a flavonoid that undergoes glucuronidation and sulfation, were found to be described better by the catenary model for the complex kinetics of substrate inhibition in metabolism. Second, estradiol-17beta-D-glucuronide (E217G), a protypic substrate of Oatp1a1, 1a4, and 1b2 and Mrp2 that underwent futile cycling with its 3-sulfate metabolite (E23S17G) via estrogen sulfotransferase (Sult1e1) and arylsulfatase C, was examined in the perfused rat liver preparation. Solutions of the AUC and clearances were solved to relate the intrinsic clearances of transporters and enzymes to understand how these affected the apparent clearances in the presence of futile cycling. Transporters and enzymes were perturbed experimentally by the intraportal injection of CC531 colon carcinoma cells for tumor induction in Wag/Rij rat livers. The protein expression of Oatp1a1 and Oatp1b2 were reduced to half whereas Sult1e1 was increased by 40% with tumor development versus the sham-operated control. These data were well predicted by the physiologically-based liver model, showing the impact of increased sulfation intrinsic clearance but not the decreased influx clearance. The TR- (Mrp2 mutant) rat model was used to examine how the absence of Mrp2 for biliary secretion of both E217G and E23S17G affected futile cycling. Absence of Mrp2 was found to result in a pseudo steady-state and reduction of the total, excretion, and metabolic clearances in the liver. The work shed new insight on the interplay between enzymes and transporters and how kinetic processes mediated by enzymes or efflux transporters affected futile cycling.
159

Application of Pharmacokinetic Theory to Examine Roles of Transporters and Enzymes in Intestinal and Hepatic Drug Disposition

Sun, Huadong 26 February 2009 (has links)
The interplay of transporters and enzymes and their transporter-enzyme was examined in Caco-2 cell monolayer and recirculating perfused rat liver preprations via both theoretical and experimental approaches. First, a Caco-2 catenary model that consisted of the apical, cellular, basolateral compartments and encompasses influx, efflux transporters and enzymes was shown to be superior to the single barrier approach for data interpretation on transporter- and enzyme- mediated processes. The kinetics of baicalein, a flavonoid that undergoes glucuronidation and sulfation, were found to be described better by the catenary model for the complex kinetics of substrate inhibition in metabolism. Second, estradiol-17beta-D-glucuronide (E217G), a protypic substrate of Oatp1a1, 1a4, and 1b2 and Mrp2 that underwent futile cycling with its 3-sulfate metabolite (E23S17G) via estrogen sulfotransferase (Sult1e1) and arylsulfatase C, was examined in the perfused rat liver preparation. Solutions of the AUC and clearances were solved to relate the intrinsic clearances of transporters and enzymes to understand how these affected the apparent clearances in the presence of futile cycling. Transporters and enzymes were perturbed experimentally by the intraportal injection of CC531 colon carcinoma cells for tumor induction in Wag/Rij rat livers. The protein expression of Oatp1a1 and Oatp1b2 were reduced to half whereas Sult1e1 was increased by 40% with tumor development versus the sham-operated control. These data were well predicted by the physiologically-based liver model, showing the impact of increased sulfation intrinsic clearance but not the decreased influx clearance. The TR- (Mrp2 mutant) rat model was used to examine how the absence of Mrp2 for biliary secretion of both E217G and E23S17G affected futile cycling. Absence of Mrp2 was found to result in a pseudo steady-state and reduction of the total, excretion, and metabolic clearances in the liver. The work shed new insight on the interplay between enzymes and transporters and how kinetic processes mediated by enzymes or efflux transporters affected futile cycling.
160

A Geochemical Characterization of a Cold-Water Acid Rock Drainage Stream Emanating From the Zn-Pb XY-deposit, Howard's Pass, Yukon Territory, Canada

Feige, Kristen B. 08 February 2011 (has links)
An acid rock drainage (ARD) stream emanating from the Zn-Pb XY-deposit in the Yukon Territory was examined in order to evaluate the physico-chemical and geochemical processes governing the distribution of dissolved elements from the creek. The creek showed very high concentrations of metals (300 mg/L Fe, 500 mg/L Zn, 15 000 µg/L Ni, 1300 µg/L Cu and 4500 µg/L Cd), low water temperatures (1 – 12°C) and was acidic to moderately acidic (pH 3.1 – 5.0). It was found that this stream experienced a strong seasonal evolution, with increased sulphate and metal concentrations and decreased pH over the course of the summer. The mineral precipitates that formed under low pH conditions were a mixture of schwertmannite, goethite, jarosite and barite, while those that formed under moderately acidic conditions were a mixture of jurbanite, hydrobasaluminite, gibbsite and an X-ray amorphous Al-sulphate phase. Most of the mineral precipitates were of inorganic origin, although microbes may have played a role in mineral formation and trace metal sequestration in some of the precipitates. All of the mineral precipitates contained anomalous concentrations of trace elements (up to 1.5 % wt Zn) and showed a seasonal evolution in their mineralogy, both of which were determined to be a function of the pH and prevailing geochemical conditions. The geochemistry of the ARD creek draining the XY-deposit was compared to another ARD creek in the area that was likely draining shales. The two creeks were compared in order to determine if ARD geochemical characteristics can be used as a tool for the mineral exploration industry.

Page generated in 0.0241 seconds