Spelling suggestions: "subject:"tta"" "subject:"åtta""
11 |
Research on Companding FiltersTsai, Ping-yu 15 July 2010 (has links)
Two kinds of companding filters are presented in this dissertation. The first one is a square-root domain filter based on operational transconductance amplifier (OTA). This one is compact and simple. The total are of the circuit excluding pads is 0.013 mm2. The supply voltage is 1.5V and the cutoff frequency can be tuned from 1.1 kHz to 35.2 kHz when the external capacitance C is 1nF. The total harmonic distortions is 0.93% and the power consumption is 152.29 £gW for a 10£gA DC input current. The other one is a tunable log-domain filter. The log domain filters uses parasitic vertical bipolar junction transistor (VBJT) in standard CMOS process for high frequency. The cut-off frequency is from 8.6 MHz to 25.8 MHz and the power dissipation is 585 £gW. All experimental results in a TSMC 0.35 £gm 2P4M CMOS process confirm the feasibility of the methodology.
|
12 |
Im Stummland : zum Exilwerk von Libuše Moníková, Jiří Gruša und Ota Filip /Kliems, Alfrun, January 2003 (has links)
Texte remanié de: Diss.--Berlin--Humboldt-Universität, 2000. / Bibliogr. p. 225-243. Index.
|
13 |
The Development of an Instrument to Measure the Self-Efficacy of Students Participating in VEX Robotics CompetitionsRobinson, Trevor P. 01 May 2014 (has links)
The number of robotics competitions has steadily increased over the past 30 years. Schools are implementing robotics competitions to increase student content knowledge and interest in science, technology, engineering, and mathematics (STEM). Companies in STEM-related fields are financially supporting robotics competitions to help increase the number of students pursuing careers in STEM among other reasons. These financial supporters and school administrations are asking what the outcomes of students participating in competitive robotics are. Few studies have been conducted to investigate these outcomes. The studies that have been conducted usually compare students in robotics to students not in robotics. There have not been any studies that compare students to themselves before and after participating in robotics competitions. This may be due to the lack of available instruments to measure student outcomes.
This study developed an instrument to measure the self-efficacy of students participating in VEX Robotics Competitions (VRC). The VRC is the world’s largest and fastest growing robotics competition available for middle and high school students. Self-efficacy was measured because of its importance to the education community. Students with higher self-efficacy tend to persevere through difficult tasks more frequently than students with low self-efficacy. A person’s self-efficacy has major influence over what interests, activities, classes, college majors, and careers he or she will pursue in life.
The self-efficacy survey instrument created through this study was developed through an occupational and task analysis (OTA), and initial content and face validity was established through the OTA process. Exploratory and confirmatory factor analyses were also conducted to assist in instrument validation. The reliability was calculated using Cronbach’s alpha. Face validity was established through the OTA process. Construct validity was established through the factor analyses. The processes of the OTA and factor analyses have created an instrument that results indicate is reliable and valid to use in further research studies.
|
14 |
System and circuit design techniques for WLAN-enabled multi-standard receiverZhang, Ling 22 November 2005 (has links)
No description available.
|
15 |
A Low Voltage, Low Power 4th Order Continuous-time Butterworth Filter for Electroencephalography Signal RecognitionMulyana, Ridwan S. 25 October 2010 (has links)
No description available.
|
16 |
Improved Synthesis Tool for Miller OTA Stage Using gm/ID MethodologyTeng, Yueh-Ching 31 March 2011 (has links)
No description available.
|
17 |
Design and implementation of an application specific multi-channel stimulator for electrokinetically-driven microfluidic devices / Design and Implementation of an Application Specific Multi-Channel Stimulator for Electrokinetically-Driven Microfluidic DevicesGomez Quinones, Jose 10 October 2011 (has links)
This dissertation presents the design and implementation of a 16-channel sinusoidal generator to stimulate microfluidic devices that use electrokinetic forces to manipulate particles. The generator has both, independent frequency and independent amplitude control for each channel. The stimulation system is based upon a CMOS application specific (ASIC) device developed using 0.35¦Ìm technology. Several generator techniques were compared based on frequency range, total harmonic distortion (THD), and on-chip area. The best alternative for the microfluidic applications is based in a triangle-to-sine converter and presents a frequency range of 8kHz to 21MHz, an output voltage range of 0V to 3.1VPP, and a maximum THD of 5.11%. The fabricated device, has a foot- print of 1560¦Ìm¡Á2030¦Ìm. The amplitude of the outputs is extended using an interface card, achieving voltages of 0V to 15VPP. The generator functionality was tested by performing an experimental set-up with particle trapping. The set-up consisted of a micromachined channel with embedded electrodes configured as two electrical ports located at different positions along the channel. By choosing specific amplitude and frequency values from the generator, different particles suspended in a fluid were simultaneously trapped at different ports. The multichannel stimulator presented here can be used in many microfluidic experiments and devices where particle trapping, separation and characterization is desired. / This dissertation presents the design and implementation of a 16-channel sinusoidal generator to stimulate microfluidic devices that use electrokinetic forces to manipulate particles. The generator has both, independent frequency and independent amplitude control for each channel. The stimulation system is based upon a CMOS application specific (ASIC) device developed using 0.35¦Ìm technology. Several generator techniques were compared based on frequency range, total harmonic distortion (THD), and on-chip area. The best alternative for the microfluidic applications is based in a triangle-to-sine converter and presents a frequency range of 8kHz to 21MHz, an output voltage range of 0V to 3.1VPP, and a maximum THD of 5.11%. The fabricated device, has a foot- print of 1560¦Ìm¡Á2030¦Ìm. The amplitude of the outputs is extended using an interface card, achieving voltages of 0V to 15VPP. The generator functionality was tested by performing an experimental set-up with particle trapping. The set-up consisted of a micromachined channel with embedded electrodes configured as two electrical ports located at different positions along the channel. By choosing specific amplitude and frequency values from the generator, different particles suspended in a fluid were simultaneously trapped at different ports. The multichannel stimulator presented here can be used in many microfluidic experiments and devices where particle trapping, separation and characterization is desired.
|
18 |
Poetika míst v románech Oty Filipa / The Poetics of Space in Ota Filip's NovelsHozman, Václav January 2013 (has links)
This thesis is focused on poetics of places and space in the novels of Czech author Ota Filip (*1930). The analysis of individual spaces displayed in Filip's work wants to demonstrate the importance of these places for the narrative construction of the autor's novels. This thesis aims to show the importance of displayed space and individual spaces for the overall sense of the fictional world in the Filip's work. The methodological basis of the thesis is the study of the Polisch scientist Janusz Sławiński: Space in Literature: Basic Division and Introductory Commonplace (2002 [1978]). Research of space displayed in the literary work based on the text of a particular novel.
|
19 |
A Review of the Kano model : A Case Study on Online Travel AgenciesLe, Thanh Huong, Karlsson, Malin January 2017 (has links)
The e-commerce has increased over the last decades, and this have indicated a change in the booking behaviour within tourism. The change within the tourism business is almost completed to go from offline to online services. This has developed a new form of companies; the online travel agencies (OTAs). As this change has been developed, not all customers is aware of the function of the OTAs. The purpose of this study is to investigate the role of the Kano Model when a third party is involved in the sales through a case study of three OTA sites. This study provides a content analysis with gathered customer reviews. The main findings of this study indicate that the five quality elements of the Kano model may be interrupted by a third party. The customer satisfaction of the OTAs can be decreased by factors that they are not able to control.
|
20 |
Risk analysis of ochratoxin A in the frame of food safety: Exposure assessmentCoronel, María Bernarda 16 December 2011 (has links)
L’ocratoxina A (OTA) és un metabòlit secundari tòxic produït per algunes especies
fúngiques dels gèneres Aspergillus i Penicillium que poden contaminar aliments i
pinsos. Aquesta micotoxina és neurotòxica, hepatotòxica, immunogènica,
teratogènica i carcinogènica en animals. En humans, l’exposició crònica a OTA
s’ha relacionat amb el desenvolupament de tumors en el tracte urinari i amb la
nefropatia endèmica dels Balcans. L’Agència Internacional per a la Investigació en
Càncer (IARC) ha classificat l’OTA com a “possiblement carcinògena per als
humans”. L’OTA pot estar present en diferents aliments d’origen vegetal com per
exemple cereals i derivats, cervesa, cafè, vi i sucs de fruita, fruits secs i fruita
deshidratada, cacau i derivats, espècies, i en alguns productes d’origen animal.
Aquesta ubiqüitat pot causar en les persones una exposició crònica.
L’avaluació de l’exposició d’una població a un determinat contaminant alimentari,
en aquesta cas particular l’OTA, pot portar-se a terme mitjançant dos
procediments. En primer lloc mitjançant la detecció d’aquest compost en els
aliments que suposadament poden estar contaminats per OTA, incloent un estudi
dels hàbits de consum de la població avaluada referent als aliments esmentats. En
segon lloc, mitjançant l’ús de biomarcardors d’exposició, la qual cosa implica la
detecció d’OTA o els seus metabòlits en fluids biològics pertanyents a individus de
la població en estudi.
L’objectiu general d’aquest treball va ser l’avaluació de la exposició a OTA de
determinats grups de persones que habiten a la Comunitat Autònoma de Catalunya
mitjançant el càlcul de la ingesta diària d’aquesta toxina. Per a fer-ho es van tenir
en compte els procediments anteriorment esmentats: es van adquirir aliments
possiblement contaminats procedents d’aquesta zona alhora que es van obtenir les
seves dades de consum dels habitants. També es van estudiar els biomarcadors
d’exposició, essent els fluids recol·lectats plasma sanguini i orina.
La incidència observada en els aliments i fluids biològics estudiats va confirmar
l’exposició de la població avaluada a l’OTA. Els nivells de contaminació en els
aliments analitzats van ser menors que els valors límit definits per la Comissió
Europea, i la seva incidència en la majoria dels casos va ser menor al 50%. Pel que
respecta als biomarcadors, la incidència va ser de gairebé el 100% en plasma, menor
en orina (12.5%) i es va observar que el metabòlit ocratoxina alfa presentava una
major incidència (60.6%) en orina que l’OTA. No es va observar correlació entre els
nivells d’OTA en plasma i el consum d’aliments possiblement contaminats però sí
que es van observar correlacions significatives entre l’OTA i el seu metabòlit
ocratoxina alfa en orina i el consum dels esmentats aliments. Es van observar
diferències en els resultats al classificar la població en funció al sexe i l’edat però no
es va poder establir una tendència general entre els estudis d’aquest treball. / La ocratoxina A (OTA) es un metabolito secundario tóxico producido por algunas
especies fúngicas de los géneros Aspergillus y Penicillium, que pueden contaminar
alimentos y piensos. Esta micotoxina es neurotóxica, hepatotóxica, inmunogénica,
teratogénica y carcinogénica en animales. En humanos, la exposición crónica a la
OTA se ha relacionado con el desarrollo de tumores en el tracto urinario, y con la
nefropatía endémica de los Balcanes. La Agencia Internacional para la
Investigación en Cáncer (IARC) ha clasificado la OTA como posiblemente
carcinógena para los humanos. La OTA puede estar presente en varios alimentos
de origen vegetal, como cereales y derivados, cerveza, café, vinos y zumos de uva,
frutos secos y fruta deshidratada, cacao y derivados, especias, y en algunos
productos de origen animal. Esta ubicuidad puede causar en las personas una
exposición crónica.
La evaluación de la exposición de una población a un contaminante presente en
alimentos, en este caso la OTA, puede llevarse a cabo mediante dos procedimientos
principales. En primer lugar, a través de la detección de este compuesto en los
alimentos que se supone puedan estar contaminados por OTA, junto con el estudio
de los hábitos de consumo de la población evaluada con respecto a los alimentos
mencionados. En segundo lugar, mediante el uso de biomarcadores de la
exposición, lo cual implica la detección de la OTA o sus metabolitos en fluidos
biológicos de individuos de la población estudiada.
El objetivo general de este trabajo fue la evaluación de la exposición a OTA por
parte de ciertos grupos de personas que habitan en la Comunidad Autónoma de
Cataluña, a través del cálculo de la ingesta diaria de la toxina. Para ello se tuvieron
en cuenta los procedimientos antes mencionados: se adquirieron en la zona ciertos
alimentos posiblemente contaminados, y se obtuvieron datos de consumo de los
habitantes. También se estudiaron los biomarcadores de la exposición, y los fluidos
recolectados fueron plasma sanguíneo y orina.
La incidencia observada en los alimentos y fluidos biológicos estudiados confirmó
la exposición de la población evaluada a la OTA. Los niveles de contaminación en
los alimentos analizados fueron menores que los valores límite definidos por la
Comisión Europea, y la incidencia en la mayoría de los casos fue menor que el
50%. En el caso de los biomarcadores, la incidencia fue de casi el 100% en plasma,
menor en orina (12.5%), y se observó que el metabolito ocratoxina alfa presentó
una mayor incidencia (60.6%) en orina que la OTA. No se observó correlación
entre los niveles de OTA en plasma y el consumo de alimentos posiblemente
contaminados, pero se observaron correlaciones significativas entre la OTA y su
metabolito ocratoxina alfa en orina y el consumo de alimentos. Se observaron
diferencias en los resultados al clasificar la población de acuerdo al sexo y la edad,
pero no se pudo establecer una tendencia general entre los estudios de este trabajo.
La ingesta diaria de OTA se estimó mediante métodos determinísticos y
probabilísticos, utilizando los datos de contaminación y consumo de alimentos.
También se estimó teniendo en cuenta los niveles de OTA en plasma, a través de la
ecuación de Klaassen. Las ingestas diarias medias y medianas de OTA obtenidas
mediante ambas metodologías fueron menores que el valor sugerido por la
Autoridad Europea en Seguridad Alimentaria (17 ng/kg peso corporal/día): hasta
un 3% de ese valor en el primer caso, y hasta el 10 % en el segundo caso. Sin
embargo, se observaron casos atípicos cuando se estimó la ingesta de OTA
teniendo en cuenta los niveles de OTA en plasma: esos valores estuvieron en el
rango de 14 a 43 ng/kg peso corporal/día. Por lo tanto, la exposición a la OTA no
producirá efectos adversos para la salud a la población general evaluada, pero se
deberían extremar las medidas para minimizar la exposición, ya que se observaron
casos extremos de exposición. / Ochratoxin A (OTA) is a toxic secondary metabolite produced by certain species of
the fungal genera Aspergillus and Penicillium that may contaminate foods and
feeds. This mycotoxin has nephrotoxic, hepatotoxic, neurotoxic, immunogenic,
teratogenic, and carcinogenic properties in animals. In humans, chronic exposure to
OTA has been related to the development of tumours in the urinary tract, and to the
Balkan endemic nephropathy. The International Agency for Research on Cancer
classified OTA as possibly carcinogenic to humans. OTA can be found in several
foods of vegetal origin, such as cereals and derivatives, beer, coffee, wines and
grape juices, nuts and dried fruits, cocoa and derivatives, spices, and in certain
animal by-products. Such ubiquity may lead to a chronic exposure by humans.
The assessment of the exposure of a population to a food contaminant, in this case,
OTA, can be done through two main procedures. In the first case, through the
detection of this compound in the foodstuffs that are supposed to be contaminated
by OTA and the study of the consumption habits of the assessed population
regarding the mentioned foodstuffs. In the second case, through the use of
biomarkers of the exposure, which implies the detection of OTA or its metabolites
in biological fluids of individuals of the selected population.
The general objective of this work was the evaluation of the exposure to OTA of
certain groups of people who live in the Spanish region of Catalonia, through the
estimation of the daily intake of the toxin. For this, the procedures mentioned
above were followed: possibly contaminated food products were purchased in this
region, and consumption data by the inhabitants were collected. Biomarkers of
exposure were also studied, and the collected fluids were blood plasma and urine.
Occurrence in certain foodstuffs and in body fluids confirmed the exposure of the
studied population to OTA. Contamination levels in the analysed foodstuffs were
below the limits set by the European Commission, and the occurrence in most cases
was below the 50%. In the case of biomarkers, occurrence was almost 100% in
plasma, lower in urine (12.5%), and it was observed that the metabolite ochratoxin
alpha had a higher incidence (60.6%) in urine than OTA. No correlation was
observed between OTA levels in plasma and the consumption of possibly
contaminated foodstuffs, but significant correlations were observed between OTA
and its metabolite ochratoxin alpha in urine and food consumption. Differences in the
results could be observed when the population was classified by gender and age,
although a general tendency among the studies of this work could not be established.
Regional or seasonal variations of the exposure were not statistically significant.
The daily intake of OTA was estimated by deterministic and probabilistic
methodologies, by modelling food consumption and contamination data. It was
also estimated by considering the levels of OTA in plasma, by means of theKlaassen equation. Mean and median results of daily intake obtained through both
methodologies were below the suggested by the European Food Safety Authority
(17 ng/kg bw/day): up to 3% of that value, in the first case, and up to 10% in the
second. However, outliers were observed when the estimation was done from OTA
levels in plasma: such values ranged from 14 to 43 ng/kg bw/day. Therefore,
exposure to OTA will not produce adverse health effects to the general assessed
population, but further efforts should be invested in order to minimize the
exposure, as extreme cases of exposure were observed.
|
Page generated in 0.043 seconds