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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.
11

Design and Implementation of One-time Implantable Spinal Cord Stimulation System

Hsu, Chia-Hao 07 July 2012 (has links)
A prototype of a one-time implantable spinal cord stimulation (SCS) system is presented in this thesis. A pair of inductive coils is used to achieve wireless power transmission and bidirectional communication. A rechargeable Li-ion battery is used to extend the lifetime of the implanted SCS device. Therefore, the number of the battery replacement surgery could be reduced such that one-time implantation is feasible. Besides, the proposed system on chip (SOC) controller and many discretes are integrated on a printed circuit board (PCB). The size of the proposed SCS device is competitive compared to the currently commercial products. The proposed SOC controller adopts a dual supply voltage scheme to reduce power consumption. The proposed SCS system employs an amplitude-shift keying (ASK) technique to carry out the data modulation and power transmission. One of the critical factors to affect efficiency of ASK-based wireless power transmission is the oscillating frequency accuracy. A ROM-less direct digital frequency synthesizer (DDFS) is presented in this thesis to fulfill such a high accuracy demand. Since the supply voltages of the discretes are diversified on a system PCB, many level converters are needed to translate different signal output voltage levels. To resolve above problem, the chip, then, must be redesigned to meet the various voltage level requirement, or added level convertors among the SOC and the discretes. Obviously, it will cause a lot of cost. A wide-range I/O buffer, thus, is proposed to resolve the compatibility problem caused by different supply voltages of discretes.
12

Modeling the Bid-Ask Spread by Option Hedging

Lin, Chi-hsien 08 August 2005 (has links)
The bid-ask spread costs consist of three components, which include order processing costs, inventory-holding costs, and adverse selection costs. In this paper, we model the inventory-holding costs of the bid-ask spread by option hedging. Theinventory-holding costs are hedged by call or put option positions. Since trades deal with the adverse selection traders are unobservable. We treat it as a latent variable, and Expected-Maximization (EM) algorithm are applied to estimate the related parameters of the model. Simulation studies are performed for several different models. Empirical results of NYSE high frequency data show that the proposed model are obtain appropriate parameter estimation when the returns satisfied normality assumption.
13

none

Sun, Chia-Liang 22 August 2008 (has links)
Family or group-owned corporations and informed trading are two features of Taiwan¡¦s capital market. Is there any relationship between the two features? Can we solve this kind of problem by some mechanism of corporate governance? These issues are common concerns for participants of capital markets and government policy makers, therefore, there are many scholars devoting themselves in the related research. This study adopts the work of McInish and Wood (1992), who measure informed trading by calculating standardized bid-ask spread. Moreover, some variables, such as trading volume, risk, stock price, company size, and listing market are taken into account because the literature indicates they may affect bid-ask spread. According to the concept of voting rights and cash flow rights introduced by La Porta, Lopez-De-Silanes, Shleifer, and Vishny (2002) and the concept of fraction of cash flow rights on the voting rights introduced by Claessens, Djankov, and Lang (2000), we use the difference ratio, which is one minus the fraction of voting rights over the cash flow rights, to measure the degree of central agency problems. The corporate governance variables, such as board size, the proportion of outside directors, and institutional shareholdings are employed as moderating variables. Multiple regression models are used to test the hypotheses. According to the test results, we find that the more cash flow rights deviate from voting rights the more informed trading will be and it can be alleviated by increasing board size and hiring big CPA firms for audit purpose; while it can be worsen by adopting more outside directors and institutional shareholdings.
14

The Informativeness of the Limit Order Book in a Periodic Call Market

Chang, Ti-Yang 17 June 2009 (has links)
Using the intraday data on the Taiwan Stock Exchange (TWSE), we address the issue of the informativeness of the limit order book in the periodic call market. We find that the pre-call information variables, i.e., the market order and the radius of the order book, have significant impacts on the trade variables, i.e., trading volume, the post-call bid-ask spread, and the trader surplus. Furthermore, we are able to show that the radius, as well as the market order, contains two differential forces in impacting these trade variables.
15

Liquidity in the German stock market : an analysis using order book data /

Klimes, Micong. January 2007 (has links)
Univ., Diss.--Frankfurt, 2004.
16

Youth Risk Behaviors and an Assessment of ASK US in Metro Atlanta High Schools

Bennett, Jennifer L 07 December 2007 (has links)
Background: HIV is increasingly prevalent among youth in the US. Objective: To assess the impact of HIV/AIDS education on health-risk behaviors associated with HIV infection in the state of Georgia. Methods: Descriptive analyses of the 2005 Georgia Student Health Survey were conducted by cross-tabulating the presence of HIV/AIDS education and each of the health-risk behaviors of interest. In addition, a survey with a sample of metro Atlanta health educators that assessed ASK US was conducted and analyzed. Results: The percentage of Georgia high school students that had ever been taught about AIDS or HIV infection in school was 91.8% (n = 1,547).The only self-reported risk factor that appeared to have a relationship with HIV/AIDS education was binge drinking (p = 0.0060). Results of the health educator survey demonstrated that ASK US is a good HIV/AIDS education tool. Conclusions: Although HIV/AIDS education is widespread, the prevalence of various health-risk behaviors remain high and, therefore, different models of HIV/AIDS education may be called for.
17

How Insiders and Informational Events Affect Bid-Ask Spreads: A Simulation-Based Approach

Runde, Andrew G 01 January 2014 (has links)
This paper will examine the effects of inside information on bid-ask spreads when the probability of insider trading and the likelihood of an informational event occurring varies using a theoretical, simulation-based approach. The results show that bid-ask spreads narrow as the number of time periods increase, regardless of probability of insider trading or the likelihood of an informational event occurring. For a high, given likelihood of an informational event occurring, the highest average spreads were found for lower probabilities of insider trading as time increased. For a high, given probability of insider trading, the highest average spreads were found for lower likelihoods of an informational event occurring as time increased. The variances increased along with the probability of insider trading as well as with the likelihood of an informational event occurring. The maximum average spread settled near 0.25, typically found for a probability of insider trading of 1 and a likelihood of an information event occurring of 0.5. The results verify previous research done by Glosten and Milgrom (1985), Easley, Hvidkjaer and O’Hara (2002) and Potterton (2011). The results also may reconcile the differences between the findings of Easley, Hvidkjaer and O’Hara (2002) and Potterton (2011).
18

Don't Ask, Don't Tell: A History, Legacy, and Aftermath

Wansac, Alexis 01 August 2013 (has links)
Though many believe some of the greatest military leaders of all time - from Alexander the Great to Julius Caesar - have engaged in sex acts with other males, and though certainly a very different political climate from that of ancient Greece or Rome, the United States military has historically never accepted homosexual sex acts within its own military, nor has the United States military accepted open homosexuals either until recently. This thesis focuses on the evolution of United States military policy towards homosexuals and the "Don't Ask, Don't Tell" (DADT) policy of the United States military in order to recommend a path that the United States can follow to provide an equal opportunity for success of openly homosexual service members. This research traces the history of policy towards homosexuality in the United States military up through the "Don't Ask, Don't Tell" policy and its repeal. This research discusses changing governmental policies towards homosexuals in the military, as well as changing public opinions about "Don't Ask, Don't Tell". This research also outlines discharges under the policy, connecting changing public opinion to the policy's eventual repeal. Through the analysis of statistics surrounding discharges, opinion surveys, and anecdotal evidence, this research evaluates the level of acceptance for openly homosexual service members in a post-DADT world. These findings will then be compared with the adjustment of troops in Great Britain and Canada, who each have experienced relative success in the integration of homosexual troops, in order to make a recommendation for a course of action that the United States could take in order to help better the adjustment of soldiers to a non-exclusionary policy.
19

Liquidity skewness in the London Stock Exchange

Hsieh, T-H., Li, Y., McKillop, D.G., Wu, Yuliang 19 December 2017 (has links)
Yes / We study liquidity on the London Stock Exchange. We find that the average bid-ask spread declines, but that the skewness of the spread increases. These results are robust to firm size, trading volume and price level. Our findings hold when the bid-ask spread is estimated utilising high frequency data. We find that the bid-ask spread prior to earnings announcements dates is significantly higher than that of post earnings announcements, suggesting that asymmetric information has driven the increase in liquidity skewness. We also find that the effect of earnings announcements is more pronounced in the 2007 global financial crisis, consistent with the notion that extreme market downturns amplify asymmetric information. Our overall evidence also implies that increased competition and transparent trading environments limit market makers' abilities to cross-subsidize bid-ask spreads between periods of high and low levels of asymmetric information. / National Natural Science Foundation of China (No. 71571197)
20

A Reliable CMOS Receiver for Power Line Communications in Integrated Circuits

Salem, Jebreel Mohamed Muftah 24 January 2013 (has links)
Power line communications (PLC) in integrated circuits (ICs) was proposed by Dr. Dong S. Ha's group in 2005. Their goal was to utilize the power distribution network for data communications as well as delivery of power, so that the routing overhead can be avoided and the number of pins in the chip can be reduced. Dr. Ha's group demonstrated through measurements the existence of pass-bands in the power distribution networks and the feasibility of power line communications in ICs. Several PLC receivers were developed to recover data superimposed on the power lines of an IC. This thesis research investigated a new PLC receiver to improve shortcomings of previous PLC receivers, specifically to improve the reliability while reducing power dissipation. The proposed PLC system adopts an amplitude shift keying (ASK) modulation to transmit and detect data through power distribution networks. The proposed PLC receiver consists of three main sub-blocks. The first sub-block is a level shifter, which lowers the offset voltage of the supply voltage to approximately 0.5VDD. The second sub-block is a signal extractor, which detects a data signal superimposed on the power line. The signal extractor is a differential amplifier, in which one input is connected through an RC low-pass filter. The DC voltage of the data signal varies in accordance with the supply voltage fluctuations and droop. The low-pass filter intends to pass only the DC term of the data signal. Since the DC voltage is common for both inputs of the differential amplifier, it is removed from the data signal through the common mode rejection of the differential amplifier. Therefore, the signal extractor can mitigate supply voltage fluctuations and droops. The last sub-block is the logic restorer, which converts the differential signal to a logic value based on a Schmitt trigger. The hysteresis of the Schmitt trigger improves the noise immunity of the receiver The proposed PLC receiver is designed and fabricated in CMOS 0.18 µm technology under the supply voltage of 1.8 V. Measurement results of the three sub-blocks and the entire PLC receiver are presented and compared with simulation results. The data rate for the measurements is set to 10.0 Mbps, and the ASK modulation scheme adopts VDD (= 1.8 V) for logic 0 and 90 mV above VDD for logic 1. The measurements show that the PLC receiver can tolerate the supply voltage drop by 0.423 V or 23.0%. The power dissipation for the receiver is 3.2 mW under 1.8 V supply. The core area of the receiver is 72.2 µm x 74.9 µm. / Master of Science

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