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SCHOOL OF MECHANICAL ENGINEERING SEMINAR
Monday, December 30 2019 at 14:00
Wolfson Building of Mechanical Engineering, Room 206

Identification of Plastic Properties from Indentation using a Bayesian-Type Statistical Approach

Alan Needleman
Texas A&M University

A mechanical property of a material is a quantity associated with a constitutive theory that purports to represent its mechanical behavior, at least in some range of circumstances. Measured properties are used to predict the mechanical response of a material under loading conditions that differ from those in the test. Quite generally, the directly measured response in a test depends on the geometry of the test specimen and the nature of the applied loading. In some circumstances, relating quantities measured in a test to material properties can be complex and may not even be unique. For example, in indentation, the force versus indentation depth response does not uniquely determine the uniaxial stress-strain response. Materials with very different uniaxial stress strain curves can give indistinguishable force versus indentation depth curves, the so called “mystical” materials. In order to uniquely identify the uniaxial stress-strain response from indentation measurements additional data is needed. Work exploring the use of a Bayesian-type statistical approach to identify the values of plastic material properties from the surface profiles as well as from the indentation force versus indentation depth response will be discussed. The indentation responses in conical indentation for three “mystical” materials are analyzed and used to identify their plastic properties. The effects of superposed fluctuations (“noise”) on the measured data and of the presumed functional form of the stress-strain response on the accuracy of the material characterization are investigated.

(The talk will be given in English)

Speaker:     Dr. Aviad Zuck
                    Department of Computer Sciences, Technion

Sunday, December 22^nd, 2019
15:00 - 16:00

Room 011, Kitot Bldg., Faculty of Engineering

Untangling Storage Complexity to Improve Performance and Security

Abstract

New generations of non-volatile storage technologies, most pertinently flash, yield tremendous performance and capacity benefits. Flash-based solid-state drives (SSDs) are integrated in an increasing variety of computing systems including mobile phones, IoT devices, and automobiles. However, the increasing proliferation of SSDs comes at a price. To minimize disruption to the storage stack of modern operating systems and protect intellectual property SSD vendors package the underlying media in a complex layer of proprietary firmware and hardware. The result is a gross misunderstanding of key features of SSDs, which in turn leads to suboptimal utilization and security vulnerabilities. In this talk I will discuss wear out attacks, a new attack vector with potential danger for mobile device integrity, and its implications for operating systems. I will also review an ongoing line of work on reverse engineering SSDs to improve their performance.

Short Bio
Aviad Zuck is a researcher in Computer Science Department at the Technion where he was previously a post-doctoral fellow hosted by Prof. Dan Tsafrir. His research interests are in the intersection of new storage technologies and data security. Aviad earned his Ph.D. from Tel Aviv University, advised by Prof. Sivan Toledo. Prior to that, he obtained a B.Sc and M.Sc in computer science (both summa cum laude) at Tel Aviv University. Aviad has also worked and interned over the years in several leading research labs in industry, including IBM Research, Microsoft Research, and PMC-Sierra.  ‏