ME Design and Freeform Fabrication of Compliant Cellular Materials with Graded Stiffness

Typically, cellular materials are designed for structural applications to provide stiffness or absorb impact via permanent plastic deformation. Alternatively, it is possible to design compliant cellular materials that absorb energy via recoverable elastic deformation, allowing the material to spring back to its original configuration after the load is released. Potential applications include automotive panels or prosthetic applications that require repeated, low-speed impact absorption without permanent deformation. The key is to arrange solid base material in cellular topologies that permit high levels of elastic deformation. To prevent plastic deformation, the topologies are designed for contact between cell walls at predetermined load levels, resulting in customized, graded stiffness profiles. Design techniques are established for synthesizing cellular topologies with customized compliance for static or quasi-static applications. The design techniques account for cell wall contact, large scale deformations, and material nonlinearities. Resulting cellular material designs are fabricated with selective laser sintering, and their properties are experimentally evaluated.Mechanical Engineerin

Advancing clinical gait analysis through technology and policy

Thesis (S.M. in Technology and Policy)--Massachusetts Institute of Technology, Engineering Systems Division, Technology and Policy Program; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2009.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Includes bibliographical references (p. 161-165).Quantitatively analyzing human gait biomechanics will improve our ability to diagnose and treat disability and to measure the effectiveness of assistive devices. Gait analysis is one technology used to analyze walking, but technical as well as economic, social, and policy issues hinder its clinical adoption. This thesis is divided into two parts that address some of these issues. Part I focuses on the role public policies have in advancing gait analysis. Through an analysis of gait analysis technologies, case studies of MRI and CT Angiography, and a high-level analysis of data standards used in gait analysis, it concludes that policies cannot directly create the institutional structures and the data standards required to advance gait analysis as a clinical diagnostic tool. Only through indirect means, such as research funding, can policies support the development of organizations to take ownership of gait analysis technologies. Part I also concludes that policies should not fund development of gait technologies but instead should fund research units working on data standards and accurate human body models. Part II focuses on a technical issue in gait analysis, namely, how to address uncertainties in joint moment calculations that occur from using different body segment inertial parameter estimation models. This is identified as a technical issue needing attention from our broader policy analysis in Part I. Using sensitivity studies of forward dynamics computer simulations coupled with an analysis of the dynamical equations of motion, Part II shows that joint moment variations resulting from different segment inertial parameters are significant at some parts of the gait cycle, particularly heel strike and leg swing.(cont.) It provides recommendations about which segment inertial parameters one should estimate more accurately depending on which joints and phases of the gait cycle one is interested in analyzing.by Junjay Tan.S.M.S.M.in Technology and Polic

Avian Influenza Pre-Pandemic Procurement: Recommendations for the US Federal Government

Many experts fear that an influenza pandemic will occur in the near future. There is currently much debate about how the US should best prepare. Previous US responses give only minimal guidance as the last major influenza pandemic occurred nearly a century ago—before flu viruses had ever been isolated

A Novel Engineering Systems Approach for Bioengineering Education: the MIT-Portugal Collaboration

This paper discusses the importance of an engineering systems approach to international bioengineering education and how a new educational research program, the MIT-Portugal Program Bioengineering Systems focus area, aims to develop future global bioengineering leaders. The program, comprising both post-graduate advanced studies and doctoral programs, commences in September 2007. Several other international-collaborative educational and research programs—such as the Cambridge-MIT Institute, the Singapore MIT Alliance, and the Socrates/Erasmus “Erasmus Programme”—offer lessons learned in international collaboration. The MPP Bioengineering Systems program differs from these programs in several respects. The unique collaboration in MPP offers an engineering systems approach, a joint degree offered by three Portuguese universities, and collaborative teaching and research efforts between MIT and Portuguese faculty and students

A Novel Engineering Systems Approach for Bioengineering Education: the MIT-Portugal Collaboration

This paper discusses the importance of an engineering systems approach to international bioengineering education and how a new educational research program, the MIT-Portugal Program Bioengineering Systems focus area, aims to develop future global bioengineering leaders. The program, comprising both post-graduate advanced studies and doctoral programs, commences in September 2007. Several other international-collaborative educational and research programs—such as the Cambridge-MIT Institute, the Singapore MIT Alliance, and the Socrates/Erasmus “Erasmus Programme”—offer lessons learned in international collaboration. The MPP Bioengineering Systems program differs from these programs in several respects. The unique collaboration in MPP offers an engineering systems approach, a joint degree offered by three Portuguese universities, and collaborative teaching and research efforts between MIT and Portuguese faculty and students

A novel engineering systems approach for bioengineering education : the MIT-Portugal collaboration

This paper discusses the importance of an engineering systems approach to international bioengineering education and how a new educationalresearch program, the MIT-Portugal Program Bioengineering Systems focus area, aims to develop future global bioengineering leaders. The program, comprising both post-graduate advanced studies and doctoral programs, commences in September 2007. Several other international-collaborative educational and research programs—such as the Cambridge-MIT Institute, the Singapore MIT Alliance, and the Socrates/Erasmus “Erasmus Programme”—offer lessons learned in international collaboration. The MPP Bioengineering Systems program differs from these programs in several respects. The unique collaboration in MPP offers an engineering systems approach, a joint degree offered by three Portuguese universities, and collaborative teaching and research efforts between MIT and Portuguese faculty and students

A Novel Engineering Systems Approach for Bioengineering Education: the MIT-Portugal Collaboration

Abstract – This paper discusses the importance of an engineering systems approach to international bioengineering education and how a new educationalresearch program, the MIT-Portugal Program Bioengineering Systems focus area, aims to develop future global bioengineering leaders. The program, comprising both post-graduate advanced studies and doctoral programs, commences in September 2007. Several other international-collaborative educational and research programs—such as the Cambridge-MIT Institute, the Singapore MIT Alliance, and the Socrates/Erasmus “Erasmus Programme”—offer lessons learned in international collaboration. The MPP Bioengineering Systems program differs from these programs in several respects. The unique collaboration in MPP offers an engineering systems approach, a joint degree offered by three Portuguese universities, and collaborative teaching and research efforts between MIT and Portuguese faculty and students

Choosing a cloud DBMS: architectures and tradeoffs

© 2019 VLDB Endowment. As analytic (OLAP) applications move to the cloud, DBMSs have shifted from employing a pure shared-nothing design with locally attached storage to a hybrid design that combines the use of shared-storage (e.g., AWS S3) with the use of shared-nothing query execution mechanisms. This paper sheds light on the resulting tradeoffs, which have not been properly identified in previous work. To this end, it evaluates the TPC-H benchmark across a variety of DBMS offerings running in a cloud environment (AWS) on fast 10Gb+ networks, specifically database-as-a-service offerings (Redshift, Athena), query engines (Presto, Hive), and a traditional cloud agnostic OLAP database (Vertica). While these comparisons cannot be apples-to-apples in all cases due to cloud configuration restrictions, we nonetheless identify patterns and design choices that are advantageous. These include prioritizing low-cost object stores like S3 for data storage, using system agnostic yet still performant columnar formats like ORC that allow easy switching to other systems for different workloads, and making features that benefit subsequent runs like query precompilation and caching remote data to faster storage optional rather than required because they disadvantage ad hoc queries

TRACER: A Framework for Facilitating Accurate and Interpretable Analytics for High Stakes Applications

10.1145/3318464.3389720SIGMOD/PODS '20: International Conference on Management of Data1747-176