Worcester Polytechnic Institute

About: Worcester Polytechnic Institute is a education organization based out in Worcester, Massachusetts, United States. It is known for research contribution in the topics: Population & Data envelopment analysis. The organization has 6270 authors who have published 12704 publications receiving 332081 citations. The organization is also known as: WPI.

Comparison of calibration methods for atomic-force microscopy cantilevers

Abstract: Th es cientific community needs a rapid and reliable way of accurately determining the stiffness of atomic-force microscopy cantilevers. We have compared the experimentally determined values of stiffness for ten cantilever probes using four different methods. For rectangular silicon cantilever beams of well defined geometry, the approaches all yield values within 17% of the manufacturer’s nominal stiffness. One of the methods is new, based on the acquisition and analysis of thermal distribution functions of the oscillator’s amplitude fluctuations. We evaluate this method in comparison to the three others and recommend it for its ease of use and broad applicability.

Wavelet-Based Approach for Structural Damage Detection

Abstract: A wavelet-based approach is proposed for structural damage detection and health monitoring. Characteristics of representative vibration signals under the wavelet transformation are examined. The methodology is then applied to simulation data generated from a simple structural model subjected to a harmonic excitation. The model consists of multiple breakable springs, some of which may suffer irreversible damage when the response exceeds a threshold value or the number of cycles of motion is accumulated beyond their fatigue life. In cases of either abrupt or accumulative damages, occurrence of damage and the moment when it occurs can be clearly determined in the details of the wavelet decomposition of these data. Similar results are observed for the real acceleration data of the seismic response recorded on the roof of a building during the 1971 San Fernando earthquake. Effects of noise intensity and damage severity are investigated and presented by a detectability map. Results show the great promise of the wavelet approach for damage detection and structural health monitoring.

Engineering education and the development of expertise

Abstract: Contributors Michael Alley, The Pennsylvania State University; Cindy Atman, University of Washington; David DiBiasio, Worcester Polytechnic Institute; Cindy Finelli, University of Michigan; Heidi Diefes-Dux, Purdue University; Anette Kolmos, Aalborg University; Donna Riley, Smith College; Sheri Sheppard, Stanford University; Maryellen Weimer, The Pennsylvania State University; Ken Yasuhara, University of Washington Background Although engineering education has evolved in ways that improve the readiness of graduates to meet the challenges of the twenty-first century, national and international organizations continue to call for change. Future changes in engineering education should be guided by research on expertise and the learning processes that support its development. Purpose The goals of this paper are: to relate key findings from studies of the development of expertise to engineering education, to summarize instructional practices that are consistent with these findings, to provide examples of learning experiences that are consistent with these instructional practices, and finally, to identify challenges to implementing such learning experiences in engineering programs. Scope/Method The research synthesized for this article includes that on the development of expertise, students' approaches to learning, students' responses to instructional practices, and the role of motivation in learning. In addition, literature on the dominant teaching and learning practices in engineering education is used to frame some of the challenges to implementing alternative approaches to learning. Conclusion Current understanding of expertise, and the learning processes that develop it, indicates that engineering education should encompass a set of learning experiences that allow students to construct deep conceptual knowledge, to develop the ability to apply key technical and professional skills fluently, and to engage in a number of authentic engineering projects. Engineering curricula and teaching methods are often not well aligned with these goals. Curriculum-level instructional design processes should be used to design and implement changes that will improve alignment.

A Restricted Additive Schwarz Preconditioner for General Sparse Linear Systems

Abstract: We introduce some cheaper and faster variants of the classical additive Schwarz preconditioner (AS) for general sparse linear systems and show, by numerical examples, that the new methods are superior to AS in terms of both iteration counts and CPU time, as well as the communication cost when implemented on distributed memory computers. This is especially true for harder problems such as indefinite complex linear systems and systems of convection-diffusion equations from three-dimensional compressible flows. Both sequential and parallel results are reported.