Slit valves play an important role in semiconductor manufacturing industry. They enable creation of a vacuum environment required for wafer processing. Due to the high volume of production in the modern semiconductor industry, slit valves experience severe degradation over their useful lifetime. If maintenance is not applied in due time, degraded valves may lead to defects in end products because of pressure loss and particle generation. In this thesis, we proposed methods for signal processing and feature extraction for analysis of slit valve vibration signatures. These methods would be used to demonstrate the ability of reliably, accurately and efficiently distinguish between each individual valve via a multi-class classification procedure. Such ability is a clear illustration of the feasibility of vibration based monitoring of the slit valve conditions. / text

Seagrasses are extremely productive coastal plant communities that serve as habitat for various types of marine and estuarine fauna and provide numerous ecosystem services. Seagrass meadows around the world have become threatened by environmental and anthropogenic pressures such as altered hydrologic regimes, physical disturbances, and eutrophication. Monitoring programs that provide high-resolution information and document changes in cover, morphometric characteristics, species composition, and tissue nutrient content across large spatial scales are critical in global conservation and management efforts. In an attempt to address the uncertainties regarding the current distribution and condition of seagrasses in the southwest Gulf of Mexico, I conducted annual sampling from 2011-2013 to examine seagrass cover and condition at 558 permanent stations. Sampling occurred in three regions of the Texas coast: the Coastal Bend (CB), Upper Laguna Madre (ULM), and Lower Laguna Madre (LLM), which together comprise over 94% of the seagrasses in Texas. Significant trends in seagrass coverage and tissue elemental composition were highly location- and species-specific. In the CB, I did not observe significant changes in seagrass cover and no spatial patterns in tissue nitrogen (N) or phosphorus (P) were apparent. However, I observed a species shift in the northern ULM, where significant decreases in Syringodium filiforme cover were coupled with significant increases in Halodule wrightii cover. Long-term salinity records at four stations throughout the study area suggest that S. filiforme mortality in the ULM in 2013 was a product of an extended period of high salinity (> 55) that began in late 2012. In LLM, there were significant increases in H. wrightii cover in the north and significant decreases in T. testudinum cover in the south, which cannot be explained based on underwater light levels, salinity, or nutrient availability. Both H. wrightii and T. testudinum displayed lower C:N, C:P, and N:P ratios, along with enriched δ¹⁵N signatures nearest urban areas, particularly in the LLM. This study illustrates the value of integrating rapid-assessment field sampling and rigorous statistical and spatial analysis into a large-scale seagrass monitoring program to uncover patterns in seagrass community structure. I detected significant trends in seagrass coverage and condition across multiple spatial and temporal scales, including a massive species replacement that coincided with a prolonged period of hypersaline conditions.

The current state of pedestrian traffic monitoring is characterized by short-duration counts over inconsistent time intervals, making it difficult to compare data temporally at a location or spatially between different locations. Practitioners require understanding of hourly pedestrian traffic periodicities in order to maximize the utility of their short-duration counts. This research deployed six automated pedestrian counters at 12 study sites representing six roadway segments in Winnipeg’s commercial zones. Pedestrian traffic data was collected in 2012 over the summer and fall seasons. This research analyzes the influence of temporal and spatial factors on hourly pedestrian traffic periodicities to enable the characterization of hourly pedestrian traffic in commercial zones. Results indicate that short-duration counts be collected from Tuesday to Thursday on days with less than four hourly precipitation events. Additionally, pedestrian traffic varies seasonally and between adjacent sidewalks in commercial zones. Finally, characterization of pedestrian traffic pattern groups requires detailed land-use data. / October 2015

ITC/USA 2014 Conference Proceedings / The Fiftieth Annual International Telemetering Conference and Technical Exhibition / October 20-23, 2014 / Town and Country Resort & Convention Center, San Diego, CA / This paper describes a device that integrates remote monitoring and control electronics into a commercial off the shelf 120 VAC power distribution strip and surge protector. An integrated microcontroller collects data on power usage from each of four AC outlets, along with two USB ports, and relays this information to a remote location. Using a conventional web browser to generate a graphical user interface, an untrained user can easily visualize their current and past energy usage patterns, and send commands to control individual outlets.

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 / In modern aircraft there is a proliferation of avionics buses. Some of these buses use industry wide standards such as ARINC 429 or AFDX while others are based on proprietary protocols. For many of the newer bus types there can be thousands of parameters on each bus. In a distributed data acquisition system the flight test engineer needs to record all of the data from each bus and monitor selected parameters in real time. There are numerous different approaches to acquiring, transmitting and recording data from avionics buses. In modern FTI there is also a proliferation of standards for recording and transmission including IRIG 106 Chapter 10, iNET and IENA. In this paper some common approaches to bus monitoring are compared and contrasted for popular buses such as ARINC 429, AFDX and Time Triggered Protocol. For each bus type the best approach is selected for reliable acquisition, speed of configuration, low latency telemetry and compact recording which is optimized for playback.

ITC/USA 2012 Conference Proceedings / The Forty-Eighth Annual International Telemetering Conference and Technical Exhibition / October 22-25, 2012 / Town and Country Resort & Convention Center, San Diego, California / The iNET program uses network technology and infrastructure to enhance traditional telemetry systems. The program's components were designed with an eye to existing and emerging technology and infrastructure, requiring the program to gather data about these systems. The methods used in this design effort can be used to characterize existing network infrastructure to determine what upgrades and changes are necessary to deploy a TmNS. This paper describes the methods used for characterizing a range network infrastructure and explores network capacity and policy issues effecting a TmNS deployment. This effort includes making estimates and taking measurements of network capacity, surveying and analyzing network routing/management policies, and proposes a system for evaluating networks for future TmNS deployments.

No description available.

Many of the European butterfly species have declined rapidly over the past decades. The cause is thought to be habitat loss due to factors such as increased tree cover, afforestation and intensified agriculture. I analyzed nation-wide data on butterfly occurrences in Sweden, to explore whether occurrences of individual species, grassland dependent species, grassland specialists, red-listed species, and moths, have increased or declined over a period of five years. I found that four species had significantly declined and eight had increased. The results were in accordance with other finds from Sweden, as well as from the UK, regarding the declining species. In contrast, the results regarding the increasing species only partly confirmed previous studies. I also found that grassland specialists and red-listed species had increased, possibly reflecting the fact that Sweden has a relatively large amount of boreal landscapes containing patches of clear-cuts and semi-natural grasslands.

Currently there is no consensus on how to account for the lateral earth pressures when designing drilled shaft retaining walls in expansive clay soils. Typically an equivalent fluid pressure is assumed which can range from 40 psf/ft to over 100 psf/ft. The range of assumptions currently in use can cause more than a factor of two difference in the maximum bending moment in the shaft. This range could cause the walls to be over-designed or under-designed. A full-scale test drilled shaft retaining wall was constructed on a site underlain by approximately 50 feet of the expansive Taylor Clay. Analysis of the wall is intended to provide information to be considered in design about the effects of the moisture cycles which cause shrinking and swelling. In order to monitor the moisture changes within the clay, 20 Time Domain Reflectometry (TDR) probes were installed behind the wall. This thesis discusses the monitoring plan, calibration, installation, and initial results from these probes. The objectives of this thesis is to provide information regarding the site conditions and reasons for using TDR probes for this project and to describe the monitoring plan, calibration, installation, and the field performance of the TDR probes and the moisture values that have been seen on the site to date. Previous studies show that difficulties can be expected when using TDR probes in highly plastic clays. Results from this study are typical of these results seen previously. The initial results show that 4 of the 20 probes are recording reasonable waveforms. However, the waveforms cannot be analyzed using conventional methods. This result was because the waveform reflection that indicates the end of the probe cannot be defined due to attenuation of the signal, which is typical of highly conductive soils. Also, the large amount of scatter in the electrical conductivity values does not allow for the moisture content to be correlated to the electrical conductivity. In order to use the TDR probes to measure moisture content at the project site, an alternative method needs to be employed to analyze available waveforms. If another method can be successfully employed for the functional probes, the subsequent step would involve recovering the probes that are not functioning properly in order to get a moisture profile along the full cantilevered height of the wall. Direct moisture measurements should also be taken periodically to provide a moisture profile. / text

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