Oversampled data converters are becoming increasingly popular for high-precision data conversion. There have been many publications on oversampled analog-to-digital (A/D) converters but relatively few on oversampled digital-to-analog (D/A) converters. In this thesis, issues concerning the analysis and design of the oversampled D/A converters are addressed. Simulation tools and analytical methods are discussed. A novel dual-quantization technique for achieving high-precision D/A conversion is proposed. A design example is presented to demonstrate that in many aspects the proposed technique is superior to existing techniques. The thesis is divided into four chapters. Chapter 1 is an introduction to the general concepts of Nyquist-rate and oversampled data converters. Chapter 2 describes some building blocks to be used in oversampled D/A converters and gives both theoretical and simulation methods for analzying them. Chapter 3 describes the proposed dual-quantization D/A converters, including the structure, the associated design issues and an example to verify the validity of this technique. Finally, Chapter 4 summarizes the properties of the simulated system and proposes some future research work. / Graduation date: 1992

This thesis presents the design of a 10 bit Analog to Digital Converter which consists of a 6 bit flash followed by a 4 bit pipeline architecture. The total system is described and the 4 bit pipeline is implemented on a bipolar process. The objective of this research is to provide an alternative approach to high speed ADC designs and to implement a pipeline ADC which samples at greater speeds than those achieved with presently existing CMOS pipeline designs. This paper presents the complete architecture, the cell design and simulated performance for each block in the pipeline, and the measured results for the four bit pipeline implementation. / Graduation date: 1993

The current study examined whether pre-birth risk factors mediate the relation between family of origin risk factors and couples’ relationship functioning after birth. Participants in the present study were 132 heterosexual couples who had their first child during the course of a larger, longitudinal study (Laurenceau et al., 2004). Results showed several significant mediation effects for both mothers and fathers. Additionally, for fathers, family-of-origin factors did not appear to directly influence their transition to parenthood, but were related to functioning before birth. For mothers, family-of-origin risk factors appeared to both directly and indirectly influence their relationship functioning after the birth of a child. Information on how pre-birth functioning risk factors mediate family of origin risk factors to the transition to parenthood is useful to psychologists who wish to intervene and assist at risk couples through the transition. This study contributes to the literature by illustrating a more complete picture of which individuals may be at risk during the transition to parenthood, which will allow psychologists to tailor their interventions to those it will help most.

In this paper, we present a low-power low-cost 6-bits, ADC using selective reference voltage technique. Using selective reference voltage technique, the different bit uses different comparator can be achieved. Meanwhile, the outputs from comparators are a binary code which can be used for generating logic condition thereby controlling the switches. Because the conventional n bits flash ADC requires 2n - 1 comparators and its power, area and input capacitance are all proportional to 2n - 1. Whereas, the proposed n bits ADC needs only n comparators which can save more power and area, and its input capacitance are proportional to n only, and keep high speed. Our proposed ADC is design by TSMC 1P6M 0.18£gm process with 6-bits resolution, 1.8V power supply. The signal input range 0.5V~1.1V, sampling rate 256MS/s, DNL +0.46LSB~ -0.49LSB, INL +0.85LSB~ -0.05LSB. In addition, the FOM of the ADC is only 0.26 pJ/Conv and the power consumption is only 4.2mW.It is good for a low-power and low cost customer electronic application.

In this paper, we investigate the information content of the insider trading. We use book to market ratio to judge the stock price of the firms which tend to be overvalued or undervalued. We suppose that the higher the book to market ratio is, the more the insider buy; vice versa. According to the past papers, seasoning equity offering often happens when the stock price is overvalued. On the other hand, the stock repurchase often happens when the stock price is undervalued. As a result, we propose that if the seasoning equity offering happens, the insiders will sell more holding stocks. If the stock repurchase happens, the insiders will buy more holding stocks. Besides, we try to understand if we can use the insider trading and the book to market ratio to be the signal of seasoning equity offerings or stock repurchase. These empirical results are not the same as our hypotheses because of the specific reason¡Xmost of the corporations in the sample are operated by family. Therefore, they won¡¦t sell their stocks easily. We have to understand the real trading motivation in the subsequences study.

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The ABR point-to-multipoint connection is now playing a more important role. Many consolidation algorithms have been proposed to solve the consolidation noise problems and the slow transient response problem. But few timeout algorithms are proposed to handle the ¡§non-responsive¡¨ branches problems for the multicast connections. We proposed a timeout algorithm which can handle the ¡§non-responsive¡¨ branches problems and with a lower implementation complexity. Simulation results also show that the proposed timeout algorithm can efficiently handle the ¡§non-responsive¡¨ branches and can use the available bandwidth within a small period of time.

This study was designed to identify the factors influencing the willingness to pay for agricultural information delivery technologies among the farmers in the Abahuzamugambi Coffee Growers Cooperative located in Butare, Rwanda. Three hundred and six farmers responded to a questionnaire that included questions about their demographic characteristics and accessibility to agricultural information technologies. Results were computed using the mean and standard deviation. T-tests and analysis of variance were conducted to determine the relationship between farmers?? demographic characteristics and their willingness to pay for selected agricultural information delivery technologies. Findings indicate that there was a correlation between farmers?? willingness to pay for agricultural information delivery technologies and some of their demographic characteristics. The farmer-to-farmer delivery technology was the most preferred as reflected by the amount of money that farmers were willing to pay for it compared to expert visits, print, radio, and television. Therefore, this technology was considered to be the most compatible with farmers?? needs in general.

Transportation is frequently cited as a barrier to health care, but rarely have researchers analyzed the problems in depth. The purpose of this study was to assess the role transportation plays in the utilization of preventive health care services among Medicaid recipients ages 0 - 20 in Texas. This preventive care is known as Early Periodic Screening and Diagnostic Testing (EPSDT), a comprehensive prevention and treatment program for Medicaid eligible children. Our computer assisted telephone interviewing based survey was administered to Medicaid recipients selected from a representative sample through a stratified sampling scheme. Binary logistic regression models were used to assess and predict factors associated with utilization of the Texas Medicaid Transportation Program (MTP) and utilization of EPSDT. We also used k-means cluster analysis to identify subgroups of Medicaid clients with particularly acute transportation barriers. Of the 1,214 Medicaid recipients interviewed, the overall odds of a Medicaid recipient being a MTP non-user was 0.94. For clients with automobile access, the probability increases to 0.98. Clients who experienced difficulties paying for gasoline decreased the overall odds to 0.86. When examining utilization of EPSDT, the overall probability of being a low utilizer was 0.59. Two factors, Spanish-speaking patients (0.21) and clients with more than one child at home (0.54) decreased the overall odds of being a low utilizer, while those with difficulty paying for gasoline increased the odds of being a low utilizer to 0.63. Increasing EPSDT utilization among the millions of Texas Medicaid recipients is an important policy objective. Because the Texas Medicaid population is large and diverse, no single approach to increasing utilization is likely to address all needs. The group concept provides a means to understand which Medicaid recipients do not access MTP services and those with low utilization rates. These groupings can be useful in targeting Medicaid clients with specific transportation difficulties. Instead of broad informational campaigns, policy makers should devise targeted strategies to promote the most appropriate types of assistance. In addition to expanding transportation options, policy makers should also examine the locations in which care is delivered, considering telemedicine, mobile health and school-based health clinics as options.

Thesis (Honors)--Liberty University Honors Program, 2008. / Includes bibliographical references.