Automated Material Handling Systems are practically ubiquitous across industry and many rely on the operation of timing belt drives, which require that the belt be tensioned properly in order to function correctly. A series of experiments was carried out in which the frequency spectrum of acoustic radiation caused by transverse vibrations of a timing belt was used to calculate the belt tension. A lumped-parameter model was developed that considers the geometric complexity of the timing belt's construction by calculating the stiffness of a single belt tooth using commercially-available finite element analysis software. This was used to modify the belt's effective stiffness suggested by the manufacturer. Based on the experimental data, a set of material properties was determined that, when used in the lumped-parameter model, resulted in tension predictions that agreed with the experiment within the 95% confidence intervals of the means. / text

ABSTRACT TWO ESSAYS ON INVESTOR SENTIMENT AND EQUITY OFFERINGS BY HSIN-HUI CHIU May 2, 2006 Committee Chair: Dr. Jason T. Greene Major Department: Finance Using monthly open-end mutual fund flows as a proxy for investor sentiment, I am able to examine the impact of sentiment on IPO volume and underpricing. I find that issuers’ filing decisions are significantly affected by the predicted future sentiment around the expected IPO dates. Furthermore, sentiment has an impact on the final offer price setting and over-allotment options exercised. While previous research documents IPO cycles with respect to other proxies for investor sentiment, I am able to examine IPO cycles and underpricing with respect to sentiment along with investor risk preferences. I hypothesize that a going public firm will try to issue its IPO when investor risk preferences are favorable to the firm’s own risk characteristics. Empirical results based on 5,661 initial public offerings between 1986 and 2004 are consistent with my hypotheses that issuers not only time the market with sentiment in general, but also attempt to incorporate investor risk preferences into their going public decisions. Furthermore, underpricing is more severe when firms issue equity during months with large inflows into equity mutual funds. In my second essay, I find that SEO firms appear to time market efficiently because of the shorter filing periods compared to the average 2-3 months of the IPOs. Also, sentiment not only affects a SEO offer price setting but also affects the over-allotment options exercised. I examine two subgroups of the SEO samples: shelf registration and non-shelf SEOs. I find that shelf-registered SEOs incorporate investor sentiment into offering price to a greater degree compared to regular SEOs. Lastly I find that investor risk preference plays a role in firms’ decision to file prospectuses with the SEC. In other words, firms rationally decide the timing of filing based on the predicted investor preference and try to match firm characteristics with investor preference around the expected SEO date.

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In a real-time system, it is crucial to ensure that all tasks of the system hold their deadlines. A missed deadline in a real-time system means that the system has not been able to function correctly. If the system is safety critical, this could potentially lead to disaster. To ensure that all tasks keep their deadlines, the Worst-Case Execution Time (WCET) of these tasks has to be known. Static analysis analyses a safe model of the hardware together with the source or object code of a program to derive an estimate of the WCET. This estimate is guaranteed to be equal to or greater than the real WCET. This is done by making calculations which in all steps make sure that the time is exactly or conservatively estimated. In many cases, however, the execution time of a task or a program is highly dependent on the given input. Thus, the estimated worst case may correspond to some input or configuration which is rarely (or never) used in practice. For such systems, where execution time is highly input dependent, a more accurate timing analysis which take input into consideration is desired. In this thesis we present a method based on abstract interpretation and counting of semantic states of a program that gives a WCET in terms of some input to the program. This means that the WCET is expressed as a formula of the input rather than a constant. This means that once the input is known, the actual WCET may be more accurate than the absolute and global WCET. Our research also investigate how this analysis can be safe when arithmetic operations causes integers to wrap-around, where the common assumption in static analysis is that variables can take the value of any integer. Our method has been implemented as a prototype and as a part of a static WCET analysis tool in order to get experience with the method and to evaluate the different aspects. Our method shows that it is possible to obtain very complex and detailed information about the timing of a program, given its input.

This study looked at 7194 completed listing from eBay Motors. Each observation contained a make, model, year, mileage, seller feedback rating, selling price, time of day ended, day of the week auction ended, auction duration, number of bidders, and number of bids for a car that had been sold on eBay Motors between March 16th and April 5th. Using this information this study looked at how timing affected the selling price of each vehicle, while holding the other variables constant. The observations are split up into four different time periods of the day (times are in Pacific Standard Time): morning (3am-8:59pm), midday (9am-2:59pm), evening (3pm-8:59pm), and night (9pm-2:59am). The regression results show that the midday time period increases the selling price of the vehicle by an average of $1445.41 for this data set. This is likely because the demand and supply side of the eBay Motors market are most equivalent during this time period compared to the other time periods.

As multi-core systems are becoming more popular in real time embedded systems, strict timing requirements for accessing shared resources must be met. In particular, a detailed latency analysis for Double Data Rate Dynamic RAM (DDR DRAM) is highly desirable. Several researchers have proposed predictable memory controllers to provide guaranteed memory access latency. However, the performance of such controllers sharply decreases as DDR devices become faster and the width of memory buses is increased. Therefore, a novel and composable approach is proposed that provides improved latency bounds compared to existing works by explicitly modeling the DRAM state. In particular, this new approach scales better with increasing number of cores and memory speed. Benchmark evaluation results show up to a 45% improvement in the worst case task execution time compared to a competing predictable memory controller for a system with 16 cores.

Thesis (M.S.)--Ohio University, November, 1999. / Title from PDF t.p.

Thesis (M.S.)--Oregon State University, 2009. / Printout. Includes bibliographical references (leaves 55-57). Also available on the World Wide Web.

Thesis (Ph. D.)--University of Rhode Island, 2003. / Typescript. Includes bibliographical references (leaves 87-93).

Thesis (Ph. D.)--University of Rhode Island, 2003. / Typescript. Includes bibliographical references (leaves 174-184).