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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.
191

A New Approach to Time Sync for Telemetry System

Lu, Chun, Kung, Changchun, Song, Jian 10 1900 (has links)
ITC/USA 2013 Conference Proceedings / The Forty-Ninth Annual International Telemetering Conference and Technical Exhibition / October 21-24, 2013 / Bally's Hotel & Convention Center, Las Vegas, NV / Instead of using a single data acquisition device, the distribute data acquisition system is broadly applied for onboard flight testing now. Therefore, the sync of data acquisition in varied devices and the real time data transportation have become the most important factors in a telemetry system. This paper presents a new approach to clock synchronization in a real time transportation network for a data acquisition system by using IRIG time code and an inner timer through network time recovery technique. This paper also illustrates how to keep the synchronization and continuity of a time tag used by each device through a precise estimation method for the difference of time resources and local inner timers.
192

On The Big Challenges of a Small Shrub : Ecological Genetics of Salix herbacea L

Cortés, Andrés J. January 2015 (has links)
The response of plants to climate change is among the main questions in ecology and evolution. Faced with changing conditions, populations may respond by adapting, going extinct or migrating. Fine-scale environmental variation offers a unique mosaic to explore these alternatives. In this thesis, I used ecological surveys, field experiments and molecular methods to study the range of possible responses at a very local scale in the alpine dwarf willow Salix herbacea L. Since gene flow may impact the potential for adaptation and migration, I first explored whether phenological divergence driven by snowmelt patterns impacts gene flow. I found that sites with late snowmelt work as sinks of the genetic diversity, as compared to sites with early snowmelt. I also used a combined approach that looked at the selection, heritability and genomic architecture of ecologically-relevant traits, as well as genomic divergence across the snowmelt mosaic. In this way, I was able to understand which genomic regions may relate to phenological, growth and fitness traits, and which regions in the genome harbor genetic variation associated with late- and early- snowmelt sites. I found that most of the genomic divergence driven by snowmelt is novel and is localized in few regions. Also, Salix herbacea has a strong female bias. Sex bias may matter for adaptation to climate change because different sexes of many dioecious species differ in several functions that may fluctuate with changing conditions. I found that the bias is uniform across environments and is already present at seeds and seedlings. A polygenic sex determination system together with transmission distortion may be maintaining the bias. Overall, fast-evolving microhabitat-driven genomic divergence and, at the same time, genetically-based trait variation at a larger scale may play a role for the ability of S. herbacea to persist in diverse and variable conditions. / SNSF Sinergia Salix
193

On-Chip Phase Measurement Design Study in 65nm CMOS Technology

Haider, Daniyal January 2015 (has links)
Jitter is generally defined as a time deviation of the clock waveform from its desired position. The deviation which occurs can be on the leading or lagging side and it can be bounded (deterministic) or unbounded (random). Jitter is a critical specification in the digital system design. There are various techniques to measure the jitter. The straightforward approach is based on spectrum analyzer or oscilloscope measurements. In this thesis an on-chip jitter measurement technique is investigated and the respective circuit is designed using 65 nm CMOS technology. The work presents the high level model and transistor level model, both implemented using Cadence software. Based on the Vernier concept the circuit is composed of an edge detector, two oscillators, and a phase detector followed by a binary counter, which provides the measurement result. The designed circuit attains resolution of 10ps and can operate in the range of 100 - 500 MHz Compared to other measurement techniques this design features low power consumption and low chip area overhead that is essential for built-in self-test (BIST) applications.
194

How the timing of performance feedback impacts incentive-based individual performance

Thornock, Todd Ammon 12 October 2011 (has links)
Performance feedback plays an important role in management accounting, as it is integral to performance measurement and evaluation. The timing of performance feedback is a critical characteristic of accounting information systems and is often a choice variable for managers and management accountants. In this dissertation, I examine the relation between the timing of outcome-based performance feedback and individual performance. I find that immediate outcome-based performance feedback, while benefiting current performance, can limit individuals’ propensity to seek learning opportunities, reducing future performance. Further, I find that feedback given after intermediate delays benefits future performance with a small cost to current performance. Lastly, feedback given after too long of a delay not only limits current performance, but also limits future performance due to the effects of information overload. Overall, I find support for an inverted-U relation between the timing of performance feedback and future performance. In a two-period setting in which the timing of outcome-based performance feedback is manipulated in the first period and feedback is unavailable in the second period, I find that participants given intermediate feedback perform significantly better in the second period than those given feedback either after no delay or after a long delay. I also investigate the processes by which performance is affected by the timing of performance feedback. These results contribute to a better understanding of the effect of performance feedback timing in complex task environments and provide insight into how delays in performance feedback can benefit or harm future performance. / text
195

Demodulation and symbol timing recovery in software radio

Wu, Yik-chung., 胡奕聰. January 2000 (has links)
published_or_final_version / abstract / toc / Electrical and Electronic Engineering / Master / Master of Philosophy
196

The Timing of Equity Issuance: Adverse Selection Costs or Sentiment?

2015 September 1900 (has links)
This study constructs a two-step model to test the most prominent market timing factors. We decompose equity issuances into 1) firm-specific components, which are predicted by firms’ characteristics, and 2) market-wide components, which are predicted by aggregate time series measures. Our evidence shows that, at the firm level, firms with higher market-to-book ratio, smaller size, more growth opportunities, and fewer tangible assets are more likely to issue equity. At the aggregate level, a greater proportion of firms issue equity in years with higher aggregate market-to-book ratio and lower asymmetric information. After controlling for the aggregate market-to-book ratio and information asymmetry, sentiment has no direct effect on equity issuance. This paper provides direct evidence that firms time their favorable market conditions to reduce adverse selection costs, and to exploit higher individual security valuations or capture growth opportunities.
197

Non-data aided digital feedforward timing estimators for linear and nonlinear modulations

Sarvepalli, Pradeep Kiran 30 September 2004 (has links)
We propose to develop new non-data aided (NDA) digital feedforward symbol timing estimators for linear and nonlinear modulations, with a view to reducing the sampling rate of the estimators. The proposed estimators rely on the fact that sufficient statistics exist for a signal sampled at the Nyquist rate. We propose an ad hoc extension to the timing estimator based on the log nonlinearity which performs better than existing estimators at this rate when the operating signal-to-noise ratio (SNR) and the excess bandwidth are low. We propose another alternative estimator for operating at the Nyquist rate that has reduced self-noise at high SNR for large rolloff factors. This can be viewed as an extension of the timing estimator based on the square law nonlinearity. For continuous phase modulations (CPM), we propose two novel estimators that can operate at the symbol rate for MSK type signals. Among the class of NDA feedforward timing estimators we are not aware of any other estimator that can function at symbol rate for this type of signals. We also propose several new estimators for the MSK modulation scheme which operate with reduced sampling rate and are robust to carrier frequency offset and phase offset.
198

Nursery Techniques Influence the Growth of Hazelnuts

Wu, Shiman 21 January 2013 (has links)
Since Ferrero SpA established a manufacturing plant in Brantford, Ontario, there has been considerable interest in developing a hazelnut industry locally. One of the issues that needs to be overcome is to supply large numbers of suitable plants rapidly. They can be micropropagated, and then grown in the nursery. Usually, it takes two years to grow suitably sized plants in the nursery. This thesis investigated methods to grow suitably sized plants in one year and evaluated the nursery systems from financial aspect. Hazelnut seedlings were planted in ellepots and plastic pots, and then subjected to three treatments: grown in a retractable roof greenhouse, treated with root pruning technology or grown in outdoor environment. Also, two transplant timings were tested: the fall of 2011 and the spring of 2012. The results showed that pot type did not influence the growth of hazelnut seedlings. The retractable roof greenhouse increased growth and the root pruning technology changed the seedlings root structure but not their growth. Transplant timing did not affect the seedlings growth in the first year in the field. The retractable roof greenhouse has the potential to produce two crops of seedlings in one growing season compared to one crop in the outdoor nursery. The estimated cost per seedling under retractable roof greenhouse was $9.31, which was $1.95 cheaper than outdoor. / Ontario Centres of Excellence and Ontario Ministry of Agriculture, Food and Rural Affairs
199

Three Essays on Updating Forecasts in Vector Autoregression Models

Zhu, Hui 30 April 2010 (has links)
Forecasting firms' earnings has long been an interest of market participants and academics. Traditional forecasting studies in a multivariate time series setting do not take into account that the timing of market data release for a specific time period of observation is often spread over several days or weeks. This thesis focuses on the separation of announcement timing or data release and the use of econometric real-time methods, which we refer to as an updated vector autoregression (VAR) forecast, to predict data that have yet to be released. In comparison to standard time series forecasting, we show that the updated forecasts will be more accurate the higher the correlation coefficients among the standard VAR innovations are. Forecasting with the sequential release of information has not been studied in the VAR framework, and our approach to U.S. nonfarm payroll employment and the six Canadian banks shows its value. By using the updated VAR forecast, we conclude that there are relative efficiency gains in the one-step-ahead forecast compared to the ordinary VAR forecast, and compared to professional consensus forecasts. Thought experiments emphasize that the release ordering is crucial in determining forecast accuracy. / Thesis (Ph.D, Economics) -- Queen's University, 2010-04-30 12:34:42.629
200

Target profitability is represented in the monkey superior colliculus during visuosaccadic foraging

KAN, JANIS YING YING 22 February 2011 (has links)
Behavioural choices of animals as they acquire resources in the wild are well characterized by foraging theory; however, the neural mechanisms underlying these behaviours are not well understood. The goal of this thesis is to understand the brain mechanisms involved in selecting and executing such foraging behaviours. To do so, rhesus monkeys performed a novel visuosaccadic foraging task while we recorded the activity of single neurons in the intermediate layers of the superior colliculus (SCi). An important innovation of this task is that both target profitability – the measure of value in the simplest case of foraging theory – and saccade choice are measured separately. We hypothesized that target profitability is represented in the SCi in addition to its well characterized role in saccade planning and preparation. Visual Foraging Task: Monkeys harvested coloured dots representing prey items by fixating them for a pre-specified handling time. On each trial, multiple prey are presented, sharing identical physical attributes except that each was one of three colours. All prey of the same colour shared the same profitability [Profitability = reward magnitude (ml)/handling time (s)]. According to foraging theory, intake of reward is maximized if prey are selected in descending order of their profitability. Indeed, we found subjects gradually approached optimal efficiency. We computed an index of the relative subjective profitability of each prey colour, which compared the rank order with which monkeys chose prey of each colour. This subjective index of profitability was then compared to concomitant SC activity attributed to the prey item in the neuron’s response field (RF). First, we found that the amount of SC activity reflected the subjective profitability of the RF targets, and established that this effect was not simply a result of saccade goal planning. Second, profitability information remains dominant throughout the handling period until reward delivery, after which activity also became selective for upcoming saccades. Together, our results highlight the prominent role of target profitability in shaping SCi activity. We propose that profitability information in the SCi may play an important role in resolving competition between numerous target representations to choose the next saccade goal. / Thesis (Master, Neuroscience Studies) -- Queen's University, 2011-02-21 15:37:43.468

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