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<title>Charles Birdsong</title>
<copyright>Copyright (c) 2011  All rights reserved.</copyright>
<link>http://works.bepress.com/cbirdson</link>
<description>Recent documents in Charles Birdsong</description>
<language>en-us</language>
<lastBuildDate>Sun, 30 Oct 2011 01:48:23 PDT</lastBuildDate>
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<title>Vibroacoustic study of circular cylindrical tubes in roller coaster rails</title>
<link>http://works.bepress.com/cbirdson/16</link>
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<pubDate>Fri, 28 Oct 2011 09:44:07 PDT</pubDate>
<description>
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	<p>Excessive noise generated by roller coasters during operation is a significant issue for amusement parks located near residential and business districts. Previous work showed that filling the rails with sand and pea gravel can provide noise reduction levels of up to 10 and 15 decibels. However, using damping materials may require additional support structures to accommodate the weight increase and, consequently, raise installation costs. This paper presents field results that characterize sound and vibration of roller coasters with different rail geometry and fill. Finite element modeling is used to compute the theoretical natural frequencies and mode shapes of a typical track section. Additionally, laboratory experimental results of lighter fill materials are presented. The results indicate that vermiculite provides similar, though less noise reduction than sand, but with a much lower additional weight. Furthermore, the handling and manufacturing characteristics are superior to the other materials investigated.</p>

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<author>Joshua I. Davis et al.</author>


<category>Articles</category>

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<title>Enhanced Vehicle Identification Utilizing Sensor Fusion and Statistical Algorithms</title>
<link>http://works.bepress.com/cbirdson/15</link>
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<pubDate>Fri, 11 Feb 2011 10:25:48 PST</pubDate>
<description>
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	<p>Several studies in the area of vehicle detection and identification involve the use of probabilistic analysis and sensor fusion. While several sensors utilized for identifying vehicle presence and proximity have been researched, their effectiveness in identifying vehicle types has remained inadequate. This study presents the utilization of an ultrasonic sensor coupled with a magnetic sensor and the development of statistical algorithms to overcome this limitation.</p>
<p>Mathematical models of both the ultrasonic and magnetic sensors were constructed to first understand the intrinsic characteristics of the individual sensors and also to provide a means of simulating the performance of the combined sensor system and to facilitate algorithm development. Preliminary algorithms that utilized this sensor fusion were developed to make inferences relating to vehicle proximity as well as type. It was noticed that while it helped alleviate the limitations of the individual sensors, the algorithm was affected by high occurrences of false positives. Also, since sensors carry only partial information about the surrounding environment and their measured quantities are partially corrupted with noise, probabilistic techniques were employed to extend the preliminary algorithms to include these sensor characteristics. These statistical techniques were utilized to reconstruct partial state information provided by the sensors and to also filter noisy measurement data. This probabilistic approach helped to effectively utilize the advantages of sensor fusion to further enhance the reliability of inferences made on vehicle identification.</p>
<p>In summary, the study investigated the enhancement of vehicle identification through the use of sensor fusion and statistical techniques. The algorithms developed showed encouraging results in alleviating the occurrences of false positive inferences. One of the several applications of this study is in the use of ultrasonic-magnetic sensor combination for advanced traffic monitoring such as smart toll booths.</p>

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<author>Stephane Roussel et al.</author>


<category>Conference Proceedings</category>

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<title>A Comparison of Two Actuators for a Semi-Active Helmholtz Resonator</title>
<link>http://works.bepress.com/cbirdson/14</link>
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<pubDate>Mon, 08 Jun 2009 15:36:16 PDT</pubDate>
<description>
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	<p>Two electro-mechanical actuators are examined for a semi-active Helmholtz resonator acoustic device. The device is used to reflect narrow band noise back to the source in an acoustic duct. The controller and actuator are used to tune the system on-line allowing optimum performance over a range of operating conditions. Actuator. dynamics play an important role in the controller design and the operation of the device. Two variations of an electro-mechanical actuator are considered here. The first uses a dual voice coil speaker with local feedback compensation and the second uses the same speaker without the compensation. It is shown that both arrangements are effective but with competing advantages. The compensated actuator provides more control authority but adds considerable background noise while the uncompensated actuator provides less control authority but adds no background noise. The choice of actuator depends on the noise control objectives of the particular application.</p>

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<author>Charles Birdsong et al.</author>


<category>Conference Proceedings</category>

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<title>A New Portable, PC Based, USB Powered Dynamic Signal Analyzer</title>
<link>http://works.bepress.com/cbirdson/11</link>
<guid isPermaLink="true">http://works.bepress.com/cbirdson/11</guid>
<pubDate>Thu, 04 Jun 2009 10:03:45 PDT</pubDate>
<description>
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	<p>A new USB powered portable 4-channel real time Dynamic Signal Analyzer and its automotive applications are described. The design and architecture lend themselves to real time NVH measurements and analysis in the field, in-vehicle or on production lines. Built-in signal conditioning provides for direct sensor power while the embedded DSP provides for signal processing on-board. Performance and implementation of FFT, digital filters and order analyses are presented.</p>

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</description>

<author>Charles Birdsong et al.</author>


<category>Conference Proceedings</category>

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<title>Undergraduate Engineers Develop Hydraulic Servo Control Systems Using Model-Based Design with Simulink</title>
<link>http://works.bepress.com/cbirdson/9</link>
<guid isPermaLink="true">http://works.bepress.com/cbirdson/9</guid>
<pubDate>Thu, 04 Jun 2009 10:03:44 PDT</pubDate>
<description>
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	<p>In the past, control engineering was the exclusive province of computer and electrical engineers with advanced degrees and years of experience in low-level programming languages. Today, engineers and students alike can use Model-Based Design to rapidly design and implement real-time control systems without having to learn low-level programming. Used throughout the automotive and aerospace industries, Model-Based Design places a high-level system model at the center of development. This approach helps engineering students understand not only the basic physics of system components, but also the interaction between components and the behavior of the overall system.</p>

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</description>

<author>Charles Birdsong</author>


<category>Articles</category>

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<title>An Electronically Tunable Resonator for Noise Control</title>
<link>http://works.bepress.com/cbirdson/10</link>
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<pubDate>Thu, 04 Jun 2009 10:03:44 PDT</pubDate>
<description>
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	<p>Many engineering systems create unwanted noise that can be reduced by the careful application of engineering noise controls. When this noise travels down tubes and pipes, a tuned resonator can be used to muffle noise escaping from the tube. The classical examples are automobile exhaust and ventilation system noise. In these cases where a narrow frequency band of noise exists, a traditional engineering control consists of adding a tuned Helmholtz resonator to reduce unwanted tonal noise by reflecting it back to the source (Temkin, 1981). As long as the frequency of the unwanted noise falls within the tuned resonator frequency range, the device is effective. However, if the frequency of the unwanted sound changes to a frequency that does not match the tuned resonator frequency, the device is no longer effective. Conventional resonators have fixed tuning and cannot effectively muffle tonal noise with time-varying frequency.</p>

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</description>

<author>Charles Birdsong et al.</author>


<category>Conference Proceedings</category>

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<title>Evaluation of Cost Effective Sensor Combinations for a Vehicle Precrash Detection System</title>
<link>http://works.bepress.com/cbirdson/13</link>
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<pubDate>Thu, 04 Jun 2009 10:03:41 PDT</pubDate>
<description>
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	<p>The future of vehicle safety will benefit greatly from precrash detection -the ability of a motor vehicle to predict the occurrence of an accident before it occurs. There are many different sensor technologies currently available for pre-crash detection. However no single sensor technology has demonstrated enough information gathering capability within the cost constraints of vehicle manufacturers to be used as a stand alone device. A proposed solution consists of combining information from multiple sensors in an intelligent computer algorithm to determine accurate precrash information. In this paper, a list of sensors currently available on motor vehicles and those that show promise for future development is presented. These sensors are then evaluated based on cost, information gathering capability and other factors. Cost sensitivity is lower in large commercial vehicles than sensitivity is lower in large commercial vehicles than in personal vehicles due to their higher initial cost and longer life span making them a good candidate for early adoption of such a system. This work forms the basis for ongoing research in developing an integrated object detection and avoidance precrash sensing system.</p>

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<author>John Carlin et al.</author>


<category>Conference Proceedings</category>

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<title>Focus on the Job in Hand:  When USB 2.0 Technology is Employed in Test and Measurement Signal Analyzer Hardware, Life Can Become So Much More Simple</title>
<link>http://works.bepress.com/cbirdson/12</link>
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<pubDate>Thu, 04 Jun 2009 10:03:15 PDT</pubDate>
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<author>Charles Birdsong et al.</author>


<category>Conference Proceedings</category>

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<title>Test Methods and Results for Sensors in a Pre-Crash Detection System</title>
<link>http://works.bepress.com/cbirdson/8</link>
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<pubDate>Tue, 26 May 2009 11:13:12 PDT</pubDate>
<description>
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	<p>Automobile safety can be improved by anticipating a crash before it occurs and thereby providing additional time to deploy safety technologies. This requires an accurate, fast and robust pre-crash sensor that measures telemetry, discriminates between classes of objects over a range of conditions, and has sufficient range and area of coverage surrounding the vehicle. The sensor must be combined with an algorithm that integrates data to identify threat levels. No one sensor provides adequate information to meet these diverse and demanding requirements. However the requirements can be met with an optimal combination of multiple types of sensors. Previous work considered criteria for evaluating various sensors to find an optimal combination. This work presents test methods and results for selected sensors proposed for use in a pre-crash detection system. The test methods include static and dynamic telemetry testing to identify the range, accuracy, reliability and operating conditions for each sensor. Each sensor is evaluated for its ability to discriminate between classes of objects. The tests are applied to ultrasonic, laser range finder and radar sensors. These sensors were selected because they provide the maximum information, cover a broad range and region and are commercially viable in passenger vehicles.</p>

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</description>

<author>Charles Birdsong et al.</author>


<category>Conference Proceedings</category>

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<title>A Compensated Acoustic Actuator for Systems with Strong Dynamic Pressure Coupling</title>
<link>http://works.bepress.com/cbirdson/7</link>
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<pubDate>Wed, 13 May 2009 10:02:00 PDT</pubDate>
<description>
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	<p>This study improves the performance of a previously developed acoustic actuator in the presence of an acoustic duct system with strong pressure coupling. The speaker dynamics and the acoustic duct dynamics are first modeled separately. The two systems are then coupled, and the resulting system is modeled. A velocity sensor is developed and used in feedback compensation. The resulting speaker system has minimal magnitude and phase variation over a 20–200 Hz bandwidth. These conclusions are verified through experimental results.</p>

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<author>Charles Birdsong et al.</author>


<category>Articles</category>

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<title>Undergraduate Research: Experiences from a Three-Year Project</title>
<link>http://works.bepress.com/cbirdson/6</link>
<guid isPermaLink="true">http://works.bepress.com/cbirdson/6</guid>
<pubDate>Wed, 13 May 2009 10:01:55 PDT</pubDate>
<description>
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	<p>There are significant benefits of research for the involved undergraduate student. These include exposure to advanced topics, introduction to research methods, and direct interaction with faculty and other students. Faculty and institutions benefit as well by the increased interaction with students – fresh eyes in research projects, more energized research groups, and more engaged alumni. However, there are some challenges in designing a research program to work primarily with undergraduates. These include the students’ lack of exposure to advanced topics, short tenure on the project, and potentially lower commitment to the results. There are a number of ways to address these concerns, however. Short student tenure and limited background can be offset by breaking up a long-term project into manageable short-term goals, allocating specific deliverables to each student, and implementing a rigorous data reporting and storage system. Motivation concerns can be handled through tying performance to student grades or to an external competition.</p>
<p>This paper presents results of applying these techniques in a multi-disciplinary vehicle sensing research project involving sixteen undergraduates over a three-year period. Although individual student time on the project ranged from only three to twelve months, all students were able to contribute to the project. Student activities were grouped into individual and small group tasks, each with specific goals and timetables. Rigorous electronic documentation and data storage techniques were employed to enable new students to come up-to-speed quickly. A mix of course credits, supplemental pay, and an intercollegiate competition were used to maintain student motivation. Project successes include high student satisfaction, conference papers, a demonstration pre-crash sensing system, and participation in an international student competition.</p>

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<author>Peter Schuster et al.</author>


<category>Conference Proceedings</category>

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<title>A Pre-Crash Simulator to Evaluate Vehicle Collision Prediction Algorithms</title>
<link>http://works.bepress.com/cbirdson/5</link>
<guid isPermaLink="true">http://works.bepress.com/cbirdson/5</guid>
<pubDate>Mon, 11 May 2009 10:55:01 PDT</pubDate>
<description>
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	<p>This paper describes a software simulator for pre-crash collision predictions. The simulator is a surrogate test bed for evaluating the performance of proposed pre-crash algorithms. It reads data from a file, transfers distance and angular position of a target to a test algorithm, and then records the algorithm’s predictions. To illustrate the simulator functionality, a simplified test algorithm is also described. This algorithm predicts collision risks based on assumptions about the size and acceleration of a target object, and the turning and braking limits of the host vehicle. The test algorithm is shown to be effective for cases where both the vehicle and the target move along straight lines but less effective for curved paths. This result is typical of the difficulty in predicting the future position of another vehicle when its motion may change suddenly in the short time before a crash event.</p>

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<author>Dana Desrosiers et al.</author>


<category>Conference Proceedings</category>

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<title>Use of Ultrasonic Sensors in the Development of an Electronic Travel Aid</title>
<link>http://works.bepress.com/cbirdson/4</link>
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<pubDate>Mon, 11 May 2009 10:55:00 PDT</pubDate>
<description>
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	<p>Ultrasonic sensors present one of the most cost-effective digital distance measurement systems available for mobile applications. Their effectiveness is limited, however, in applications involving complex environments and when information on sensor position is unavailable. This paper focuses on the implementation and limitations of ultrasonic sensors and system design considerations during development of an Electronic Travel Aid [ETA] for the visually impaired utilizing ultrasonic sensors and vibrotactile feedback. Our work with sensors included signal filtering and triangulation to improve performance characteristics of ultrasonic-based measurements. Additionally, we describe the use of computer modeling to aid in the design of ultrasonic sensor systems.</p>

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</description>

<author>Chris Gearhart et al.</author>


<category>Conference Proceedings</category>

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<title>Developing a MATLAB/Simulink RTWT Based Hydraulic Servo Control Design Experiment</title>
<link>http://works.bepress.com/cbirdson/3</link>
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<pubDate>Mon, 11 May 2009 10:55:00 PDT</pubDate>
<description>
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	<p>While one of the stated goals of the Mechanical Engineering Controls course is to develop the tools to design a controller, previous lab experiences did not include an experimental exercise in controller design. This was primarily due to the difficulty in implementing a controller that is robust and flexible enough to accommodate different student designs within the short time constraints of a three hour lab period. This paper describes an effort to use the Mathworks Real Time Windows Target to implement student controller designs on real hardware in a lab setting. Students use experimental data and a physically based model to design the controller for a hydraulic servo control system. A system transfer function is estimated from a frequency response experiment. Then a controller design is conducted using classical PID controller design techniques and a Simulink model. Finally when students have completed a controller design, they are allowed to implement it on the experimental apparatus and measure the system performance. They are then given a second chance to fine tune the model. The control is implemented with the Real Time Windows Target using a data acquisition card on a PC. A competition for the best performance also creates an exciting and competitive learning atmosphere. Assessments are presented that indicate the improvement in learning outcomes from the change in the lab exercise.</p>

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</description>

<author>Charles Birdsong</author>


<category>Conference Proceedings</category>

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<title>Research in the Undergraduate Environment</title>
<link>http://works.bepress.com/cbirdson/2</link>
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<pubDate>Mon, 11 May 2009 10:54:59 PDT</pubDate>
<description>
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	<p>The benefits of research experiences for undergraduates are significant. For many faculty, these were the experiences that convinced us to pursue further education and a career in academia. However, performing research at an undergraduate institution carries with it certain challenges. In traditional research institutions, doctoral students perform most of the research activities, led by the faculty. These students have completed at least their undergraduate courses and can be expected to remain on the research team for four to six years. In contrast, at an undergraduate institution students may start in the group with only one or two engineering courses completed, and will remain in the group for only two or three years. Other constraints at these schools are high teaching loads and limited research facilities. Because of these concerns, some faculty may choose to avoid research activities while others may perform only research that requires limited student involvement. However, as the primary focus at these institutions is the education of undergraduates, the ideal research plan will provide opportunities to include students significantly in the process.</p>
<p>One way to perform research with heavy undergraduate involvement is to select an appropriate topic and develop a stable undergraduate research group that builds and maintains knowledge over time. Such a research group requires tasks encompassing many skill levels, a steady funding source, and an orderly progression of short-term goals for each student. Web based communication and archiving tools can be used to share and pass on data, references and information. Selecting the research topic, obtaining funding, and initially training and organizing the student team are the major start-up tasks. The benefits for the students and the faculty member are worth these efforts.</p>

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<author>Charles Birdsong et al.</author>


<category>Conference Proceedings</category>

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