Engineering Commons^™

The Effect Of Different Hormone Replacement Therapy Regimens On The Mechanical Properties Of Rat Vertebrae, Debbie Chachra, M. Kasra, Carla Vanin, N. Maclusky, R. Casper, Marc Grynpas

Debbie Chachra

The purpose of this study was to examine the effects of estrogen replacement, in concert with three different progestin regimens, on the mechanical properties of rat lumbar vertebrae. Ninety-two Sprague-Dawley rats (11 months old) were divided into six groups for treatment. The first group was an intact control, the second group (OVX) was ovariectomized only, and the third group (estrogen-only) was ovariectomized and received continuous estrogen through a 17-estradiol implant. The remaining groups were ovariectomized and received estrogen and progestin (norethindrone, NET) therapy; 3 g of NET was injected daily (estrogen plus continuous NET), or 6 g of NET was …

The Effect Of Fluoride Treatment On Bone Mineral In Rabbits, Debbie Chachra, C. Turner, A. Dunipace, Marc Grynpas

Debbie Chachra

Fluoride therapy has been used clinically for many years, but its use remains controversial and many basic questions remain unanswered. Accordingly, this study returns to an animal model to study the effects of high doses of fluoride on bone mineral in rabbits. Twelve rabbits, aged 3½ months at the start of the study, received drinking water fluoridated at 100 ppm while their 12 control counterparts drank distilled water. All rabbits were sacrificed after 6 months. Fluoride was readily incorporated into femoral cortical bone (7473 ± 966 ppm F versus 1228 ± 57 ppm in controls; P < 0.00005). Fluoride therapy led …

The Effect Of Streamwise Vortices On The Frost Growth Rate In Developing Laminar Channel Flows, Brian Storey, Anthony Jacobi

Brian Storey

An experimental study is presented to assess the influence of streamwise vortices on frost growth in a steady, developing, laminar channel flow. Using a simple model and scale analysis, frost growth rate (ablimation) data are normalized with respect to temperature, humidity and time. Measurements from baseline experiments in a rectangular channel are found to be accurately correlated using the proposed scaling relation. Upon introducing streamwise vortices in the channel flow, frost growth still follows the scaling relation, but local growth rates were observed to increase by more than 7% in regions where the streamwise vortices induce a surface-normal flow toward …

A Semi-Automatic Approach For Project Assignment In A Capstone Course, Mark Chang, Allen Downey

Mark L. Chang

This paper presents a semi-automatic approach to assigning students to project teams for a year-long, industry-sponsored senior capstone course. Successful assignment requires knowl- edge of at least individual project requirements, student skills, student personalities, and student project preferences. This mix of hard skills, soft skills, and interpersonal impres- sions requires human involvement to produce a high-quality assignment. The importance of faculty input often requires that the assignment process be labor- and time-intensive.

Our approach attempts to reduce the time required to perform this assignment by selectively automating parts of the task flow. An automated search uses a randomized greedy algorithm …

A Parameterized Stereo Vision Core For Fpgas, Mark Chang, Stephen Longfield

Mark L. Chang

We present a parameterized stereo vision core suitable for a wide range of FPGA targets and stereo vision applications. By enabling easy tuning of algorithm parameters, our system allows for rapid exploration of the design space and simpler implementation of high-performance stereo vision systems. This implementation utilizes the census transform algorithm to calculate depth information from a pair of images delivered from a simulated stereo camera pair. This work advances our previous work through implementation improvements, a stereo camera pair simulation framework, and a scalable stereo vision core.

Precis: A Usercentric Word-Length Optimization Tool, Mark Chang, Scott Hauck

Mark L. Chang

Translating an algorithm designed for a general-purpose processor into an algorithm optimized for custom logic requires extensive knowledge of the algorithm and the target hardware. Precis lets designers analyze the precision requirements of algorithms specified in Matlab. The design time tool combines simulation, user input, and program analysis to help designers focus their manual precision optimization efforts.

A Long-Duration Study Of User-Trained 802.11 Localization, Andrew Barry, Benjamin Fisher, Mark Chang

Mark L. Chang

We present an indoor wireless localization system that is capable of room-level localization based solely on 802.11 network signal strengths and user-supplied training data. Our system naturally gathers dense data in places that users frequent while ignoring unvisited areas. By utilizing users, we create a comprehensive localization system that requires little off-line operation and no access to private locations to train. We have operated the system for over a year with more than 200 users working on a variety of laptops. To encourage use, we have implemented a live map that shows user locations in real-time, allowing for quick and …

A Blank Slate: Creating A New Senior Engineering Capstone Experience, Mark L. Chang, Jessica Townsend

Mark L. Chang

This paper presents some of the challenges, successes, and experiences in designing a new senior engineering capstone program at the Franklin W. Olin College of Engineering. Senior capstone design programs in engineering colleges have evolved over many years and are often modified and reinvented to keep up with the needs of both students and external constituencies. Harvey Mudd College’s Clinic program is one of the largest and longest-running capstone programs in the country that relies heavily on industry sponsors to provide real world problems and funding to execute the projects. For many reasons, and in no small way because of …

Low-Cost Stereo Vision On An Fpga, Chris A. Murphy, Daniel Lindquist, Ann Marie Rynning, Thomas Cecil, Sarah Leavitt, Mark L. Chang

Mark L. Chang

We present a low-cost stereo vision implementation suitable for use in autonomous vehicle applications and designed with agricultural applications in mind. This implementation utilizes the Census transform algorithm to calculate depth maps from a stereo pair of automotive-grade CMOS cameras. The final prototype utilizes commodity hardware, including a Xilinx Spartan-3 FPGA, to process 320times240 pixel images at greater than 150 frames per second and deliver them via a USB 2.0 interface.

Automated Least-Significant Bit Datapath Optimization For Fpgas, Mark L. Chang, Scott Hauck

Mark L. Chang

In this paper, we present a method for FPGA datapath precision optimization subject to user-defined area and error constraints. This work builds upon our previous research which presented a methodology for optimizing the dynamic range- the most significant bit position. In this work, we present an automated optimization technique for the least-significant bit position of circuit datapaths. We present results describing the effectiveness of our methods on typical signal and image processing kernels.

Interactionless Calendar-Based Training For 802.11 Localization, Mark Chang, Andrew J. Barry, Noah L. Tye

Mark L. Chang

This paper presents our work in solving one of the weakest links in 802.11-based indoor-localization: the training of ground-truth received signal strength data. While crowdsourcing this information has been demonstrated to be a viable alternative to the time consuming and accuracy-limited process of manual training, one of the chief drawbacks is the rate at which a system can be trained. We demonstrate an approach that utilizes users' calendar and appointment information to perform interactionless training of an 802.11-based indoor localization system. Our system automatically determines if a user attended a calendar event, resulting in accuracy comparable to our previously published …

Work In Progress - Impact Of Early Design Instruction On Capstone Experiences, Mark L. Chang, Jessica Townsend

Mark L. Chang

In the Olin College curriculum, students have significant, early, and continuous exposure to user-oriented design principles. As a result, our students have a very user-centered approach to problem solving that has affected our yearlong, industry-sponsored capstone in several ways. We have reflected on five years of capstone engagements in order to learn how our program has changed because of the design emphasis in our curriculum. The significance of our work is to inform the many departments that are already undertaking design-centric curriculum reform on how they may modify their capstone experiences to best take advantage of new student understanding, and …

A Blank Slate: Creating A New Senior Engineering Capstone Experience, Mark L. Chang, Jessica Townsend

Jessica Townsend

This paper presents some of the challenges, successes, and experiences in designing a new senior engineering capstone program at the Franklin W. Olin College of Engineering. Senior capstone design programs in engineering colleges have evolved over many years and are often modified and reinvented to keep up with the needs of both students and external constituencies. Harvey Mudd College’s Clinic program is one of the largest and longest-running capstone programs in the country that relies heavily on industry sponsors to provide real world problems and funding to execute the projects. For many reasons, and in no small way because of …

Work In Progress - Impact Of Early Design Instruction On Capstone Experiences, Mark Chang, Jessica Townsend

Jessica Townsend

In the Olin College curriculum, students have significant, early, and continuous exposure to user-oriented design principles. As a result, our students have a very user-centered approach to problem solving that has affected our yearlong, industry-sponsored capstone in several ways. We have reflected on five years of capstone engagements in order to learn how our program has changed because of the design emphasis in our curriculum. The significance of our work is to inform the many departments that are already undertaking design-centric curriculum reform on how they may modify their capstone experiences to best take advantage of new student understanding, and …

'Kinetic Sculptures': A Centerpiece Project Integrated With Mathematics And Physics, Yevgeniya Zastavker, Jill Crisman, Mark Jeunnette, Burt Tilley

Yevgeniya V. Zastavker

An integrated set of courses, or Integrated Course Block (ICB), developed for incoming first-year students at the Franklin W. Olin College of Engineering, is presented. Bound by a common theme of `Kinetic Sculptures', the individual courses in this ICB are mathematics (single variable calculus and ordinary differential equations), physics (kinetics and dynamics of linear and rotational motion, thermodynamics and fluids), and an open-ended engineering project. The project part of the ICB allows students to explore the motion through the design of kinetic (moving) sculptures while utilizing the mathematics and physics concepts learned in the accompanying courses. This paper considers the …

Faculty On Integrated Project-Based Learning, Yevgeniya Zastavker, Casey Canfield

Yevgeniya V. Zastavker

This paper examines the experiences, perspectives, and concerns of faculty involved in implementing a first-year integrated project-based engineering curriculum as they attempt to understand and reconcile their own and students’ views, attitudes, and beliefs regarding project-based learning (PjBL). A semi-structured, open-ended interview protocol is employed with seven mathematics and physics faculty participants. Grounded theory is used to identify the following themes: divergence of faculty perceptions regarding the effectiveness of an integrated approach in teaching and learning, the value of projects, and conflicting student expectations.

Analysis Of Segmentation Algorithms For Pavement Distress Images, Allen Downey, Haris N. Koutsopoulos, Ibrahim El Sanhouri

Allen B. Downey

Collection and analysis of pavement distress data is an important component of any pavement‐management system. Various systems are currently under development that automate this process. They consist of appropriate hardware for the acquisition of pavement distress images and, in some cases, software for the analysis of the collected data. An important step in the automatic interpretation of images is segmentation, the process of extracting the objects of interest (distresses) from the background. We examine algorithms for segmenting pavement images and evaluate their effectiveness in separating the distresses from the background. The methods examined include the Otsu method, Kittler's method, a …

Primitive-Based Classification Of Pavement Cracking Images, Allen Downey

Allen B. Downey

Collection and analysis of pavement distress data are receiving attention for their potential to improve the quality of information on pavement condition. We present an approach for the automated classificaton of asphalt pavement distresses recorded on video or photographic film. Based on a model that describes the statistical properties of pavement images, we develop algorithms for image enhancement, segmentation, and distress classification. Image enhancement is based on subtraction of an “average” background: segmentation assigns one of four possible values to pixels based on their likelihood of belonging to the object. The classification approach proceeds in two steps: in the first …

Method Of And Apparatus For Computer-Aided Generation Of Variations Of A Sequence Of Symbols, Such As A Musical Piece, And Other Data, Character Or Image Sequences, Diana Dabby

Diana Dabby

A procedure for generating different variations of a sequence of symbols, such as a musical piece, based on the properties of a chaotic system--most notably, sensitive dependence on the initial condition--is described and demonstrated. This method preferably uses a fourth order Runge-Kutta implementation of a chaotic system. Bach's Prelude in C Major from the Well-Tempered Clavier, Book I serves as the illustrative example since it is well-known and easily accessible. Variations of the Bach can be heard that are very close to the original while others diverge further. The system is designed for composers who, having created a through-composed work …

Creating Musical Variation, Diana Dabby

Diana Dabby

Inspiration for composition may come from natural sounds, chance, and methods based on chaos theory.

Work In Progress- Understanding Discomfort: Student Responses To Self-Direction, Jonathan Stolk, Mark Somerville, John Geddes, Rob Martello

John B. Geddes

The literature consistently reports that students express some degree of discomfort when they are thrown into self-directed learning environments. In this paper, we present the preliminary results of an investigation of the causes of student discomfort in several different self-directed project-based courses. Our results suggest that student motivation and opportunities for the development of deep understanding and transferable skills are important in creating a positive self-directed learning experience. Negative experiences and student discomfort in self-directed environments may stem from problems with self-regulation, low self-perceptions of content learning, lack of personal engagement with the topic, and difficulties related to the social …

Stability Of A Microvessel Subject To Structural Adaptation Of Diameter And Wall Thickness, Alisha Sarang-Sieminski, John Geddes, Ilari Shafer, Rachel Nancollas, Morgan Boes

John B. Geddes

Vascular adaptation—or structural changes of microvessels in response to physical and metabolic stresses—can influence physiological processes like angiogenesis and hypertension. To better understand the influence of these stresses on adaptation, Pries et al. (1998, 2001a,b, 2005) have developed a computational model for microvascular adaptation. Here, we reformulate this model in a way that is conducive to a dynamical systems analysis. Using th ese analytic methods, we determine the equilibrium geometries of a single vessel under different conditions and classify its type of stability. We demonstrate that our closed-form solution for vessel geometry exhibits the same regions of stability as the …

Work In Progress – Building Autonomous Students: Modeling Curricular Approaches For Lifelong Learning, Jonathan Stolk, Rob Martello, John Geddes

John B. Geddes

Student development of self-directed learning skills is critical for success in today’s rapidly-changing engineering world. The details of how instructors may best foster engagement in life-long learning, however, are unclear; many educators have struggled to define, implement, and assess lifelong learning in engineering curricula. We present a framework for student autonomy that may serve as a useful curriculum design tool by aiding instructors’ consideration of learner responsibility and development. The model describes lifelong learning as a set of choices over which students may gradually gain control. These areas of learning autonomy include four question categories: why is learning necessary, what …

Engineering Students' Conceptions Of Self-Directed Learning, Jonathan Stolk, John Geddes, Mark Somerville, Robert Martello

John B. Geddes

Researchers have developed numerous theories and developmental models to describe self directed learning, lifelong learning, and self-regulated learning. The literature includes a large body of research that illustrates the cognitive, metacognitive, motivational, affective, and behavioral attributes of self-directed learners; the influences of social and physical environment on self-directed learning development; and the roles of self-perceptions, causal orientations,learning conceptions, and demographics in determining certain self-directed learning responses. But how do undergraduate engineering students characterize and critique self-directed learning? This paper evaluates the responses of engineering students to questions regarding the definition of self-direction and the primary positive or negative factors contributing …

Work In Progress- Understanding Discomfort: Student Responses To Self-Direction, Jonathan Stolk, Mark Somerville, John Geddes, Rob Martello

Jonathan Stolk

The literature consistently reports that students express some degree of discomfort when they are thrown into self-directed learning environments. In this paper, we present the preliminary results of an investigation of the causes of student discomfort in several different self-directed project-based courses. Our results suggest that student motivation and opportunities for the development of deep understanding and transferable skills are important in creating a positive self-directed learning experience. Negative experiences and student discomfort in self-directed environments may stem from problems with self-regulation, low self-perceptions of content learning, lack of personal engagement with the topic, and difficulties related to the social …

Student-Directed, Project-Based Learning In An Integrated Course Block, Jonathan Stolk, Rob Martello, Steven Krumholz

Jonathan Stolk

Imagine a course block in which students discuss the cultural implications of 17th century iron working in North America in one hour, and design experiments to examine connections between composition and strength in modern steel padlocks immediately afterward. In the Paul Revere:Tough as Nails course block, students don’t just study materials science and history of technology topics … they experience them. Through a series of readings, discussions, and self designed projects, students explore materials science concepts alongside the social, cultural, and environmental factors that shaped technological and scientific history. Although some formal in class activities are planned, many class sessions …

Engineering Students' Conceptions Of Self-Directed Learning, Jonathan Stolk, John Geddes, Mark Somerville, Robert Martello

Jonathan Stolk

Researchers have developed numerous theories and developmental models to describe self directed learning, lifelong learning, and self-regulated learning. The literature includes a large body of research that illustrates the cognitive, metacognitive, motivational, affective, and behavioral attributes of self-directed learners; the influences of social and physical environment on self-directed learning development; and the roles of self-perceptions, causal orientations,learning conceptions, and demographics in determining certain self-directed learning responses. But how do undergraduate engineering students characterize and critique self-directed learning? This paper evaluates the responses of engineering students to questions regarding the definition of self-direction and the primary positive or negative factors contributing …

Paul Revere In The Science Lab: Integrating Humanities And Engineering Pedagogies To Develop Skills In Contextual Understanding And Self-Directed Learning, Rob Martello, Jonathan Stolk

Jonathan Stolk

ABET, ASEE, and the wider engineering community have long acknowledged the potential benefits of interdisciplinary education, including the opportunity to develop non-technical skills such as communication and teamwork while cultivating a broader awareness of the ethical, societal, historical, and environmental impacts of engineering work. Instructors have encountered many challenges in planning and implementing integrated courses, such as the difficulty of coordinating the teaching methods, content, and learning objectives of different academic disciplines in a finite and already overcrowded curriculum. This paper presents the goals, design approach, implementation, and selected outcomes of one integrated project-based course (using Paul Revere and other …

Work In Progress- Understanding Discomfort: Student Responses To Self-Direction, Jonathan Stolk, Mark Somerville, John Geddes, Rob Martello

Robert Martello

The literature consistently reports that students express some degree of discomfort when they are thrown into self-directed learning environments. In this paper, we present the preliminary results of an investigation of the causes of student discomfort in several different self-directed project-based courses. Our results suggest that student motivation and opportunities for the development of deep understanding and transferable skills are important in creating a positive self-directed learning experience. Negative experiences and student discomfort in self-directed environments may stem from problems with self-regulation, low self-perceptions of content learning, lack of personal engagement with the topic, and difficulties related to the social …