MAE Colloquium - Winter 2015
The Aerospace Engineering Colloquium (AE 598) is a required course that satisfies the professional development component of the Master of Aerospace Engineering (MAE). MAE students are required to complete nine (9) credits of colloquium participation to satisfy the degree requirements. However, all members of the UW community are welcome to attend and participate.
Topics may include current research and advances in aerospace technology as well as other themes relevant to the professional development of aerospace engineers. To earn credit for this course, students must complete a required set of writing assignments.
Faculty Coordinator: Prof. Mehran Mesbahi
January 5 - First Meeting
- Mehran Mesbahi, Professor
William E. Boeing Department of Aeronautics & Astronautics, University of Washington
Welcome and Introduction to MAE Colloquium
Multiple Target Tracking from Airborne Cameras
The technology surrounding unmanned air vehicles has developed at a rapid pace over the past ten years. Current autopilots and autonomy modes have the potential to transform numerous industries and government services, once airspace regulation issues have been addressed. Many potential applications involve tracking features, or objects on the ground using EO/IR cameras, lidar, or radar. However, current object tracking technologies are not adequate for UAV applications. This talk will present a new multiple target tracking algorithm that is based on the random sample consensus (RANSAC) algorithm that is widely used in computer vision. A recursive version of the RANSAC algorithm will be discussed, and its extension to tracking multiple dynamic objects will be explained. In essence, the Recursive RANSAC algorithm enables multiple dynamic target tracking in the presence of significant outlier measurements. The performance of R-RANSAC will be compared to state of the art target tracking algorithms in the context of problems that are relevant to UAV applications.
(1) Niedfeldt, P. C., Beard, R. W., (2013). “Recursive RANSAC: Multiple Signal Estimation with Outliers.” 9th IFAC Symposium on Nonlinear Control System.
(2) Niedfeldt, P. C., Beard, R. W., “Multiple Target Tracking Using Recursive RANSAC.” American Control Conference, 2014.
University Holiday - No Colloquium This Week
"Fly-By-Wire" Technology in Aerospace Today
- Kioumars Najmabadi, Technical Fellow
Boeing Commercial Aircraft - Flight Controls Systems, The Boeing Company
Fly-By-Wire technology has introduced a new degree of freedom to optimize airplane configuration and its performance. This presentation includes discussion of different elements considered in the control and augmentation system design using FBW technology. The following topics are briefly discussed: integrated development process, safety considerations and requirements, integrity and availability requirements, system architecture, 777 command and augmentations functionalities, example of pitch axis control law, verification and validation, pilot- vehicle dynamic system, handling quality and pilot induced oscillation rating criteria.
**Special Meeting Time**
Wednesday, February 4, 11:30am
Robotics and the Lessons of Cyberlaw
Two decades of analysis have produced a rich set of insights as to how the law should apply to the Internet’s peculiar characteristics. But, in the meantime, technology has not stood still. The same public and private institutions that developed the Internet, from the armed forces to search engines, have initiated a significant shift toward robotics and artificial intelligence.
This talk examines what the introduction of a new, equally transformative technology means for cyberlaw and policy. Robotics has a different set of essential qualities than the Internet and, accordingly, will raise distinct legal issues. Robotics combines, for the first time, the promiscuity of data with the capacity to do physical harm; robotic systems accomplish tasks in ways that cannot be anticipated in advance; and robots increasingly blur the line between person and instrument.
Robotics will prove “exceptional” in the sense of occasioning systematic changes to law, institutions, and the legal academy. But we will not be writing on a clean slate: Many of the core insights and methods of cyberlaw will prove crucial in integrating robotics, and perhaps whatever technology follows.
(1) Calo, Ryan, "Robotics and the Lessons of Cyberlaw" (February 28, 2014). California Law Review, Vol. 103, 2015; University of Washington School of Law Research Paper No. 2014-08.
(2) Calo, Ryan, "The Drone as Privacy Catalyst" (December 12, 2011). Stanford Law Review Online, Vol. 64, pp. 29-33 (2011).
Sample Return from Small Solar System Objects
The ability to easily return a sample from solar system objects would enable major advances in understanding the origins of the solar system and the development of early life. Developments in a new innovative system for sample return are presented. This system uses a high velocity impact at a few hundred meters per second to produce a core sample which is ejected shortly after impact. Return to the spacecraft is achieved by a tether system attached to the return sample container. Material properties are very important to the overall survivability of the system at impact. Component testing in the laboratory, modeling and field tests are described. Student involvement has also been a very important aspect of the development of the project.
University Holiday - No Colloquium This Week
Harnessing Deformation and Instability of Soft Periodic Structures for Tunable Structures and Devices
Structures made of soft materials such as elastomers and gels can make a large change of their architecture in response to stimuli. If excessive deformation is applied, they may become unstable. Beyond the instability threshold, structures can undergo dramatic changes of the architecture and may form new patterns. The non-linear behavior of highly deformable structures can be utilized to create a new class of tunable materials that can change their functionalities through large deformations and dramatic geometric rearrangements induced by instabilities. In my presentation, I will talk about how we can harness the behavior of soft periodic structures to tune propagation of elastic waves and energy absorption as well as the chirality and long-range order formation from the structures. While instabilities have been traditionally considered as failure modes to avoid, our studies show new ways of utilizing the phenomena for novel structures and devices.
(1) K. Bertoldi, P. M. Reis, S. Willshaw and T. Mullin, “Negative Poisson's Ratio Behavior Induced by an Elastic Instability,” Advanced Materials, 22, 361-366 (2010).
(2) S. H. Kang, S. Shan, W. Noorduin, M. Khan, J. Aizenberg, and K. Bertoldi, “Buckling-Induced Reversible Symmetry Breaking and Chiral Amplification Using Supported Cellular Structures,” Advanced Materials, 25, 3380-3385 (2013).
(3) S. H. Kang, S. Shan, A. Kosmrlj, W. L. Noorduin, S. Shian, J. C. Weaver, D. R. Clarke, and K. Bertoldi, “Complex Ordered Patterns in Mechanical Instability Induced Geometrically Frustrated Triangular Cellular Structures,” Physical Review Letters, 112, 09870 (2014).
(4) S. Shan, S. H. Kang, P. Wang, C. Qu, S. Shian, E. R. Chen, J. C. Weaver, and K. Bertoldi, “Harnessing Multiple Folding Mechanisms in Soft Periodic and Porous Structures to Design Highly Tunable Phononic Crystals,” Advanced Functional Materials, 24, 4935 (2014).
Analysis and Calibration of Stochastic Computer Models of Epidemiological Processes
Mathematical models of infectious diseases have been used for over a century to aid resource allocation and intervention planning. While simple deterministic models based on ordinary differential equations enable macroscopic insights, detailed questions surrounding the global eradication of diseases such as polio and malaria recently spurred the development of stochastic individual-based models. The resulting mechanistic models span multiple spatiotemporal scales by connecting within-host dynamics to population-level migration and transmission. While this modeling paradigm offers a plethora of benefits, it comes at the cost of increased computation complexity that necessitates the research and development of specialized algorithms. This talk will focus on two such algorithms. The first is the Separatrix algorithm for localizing regions of parameter space that achieve a modeling objective, e.g. eradication, with a specified success probability. The second addresses the challenge of stochastic model calibration by augmenting Incremental Mixture Importance Sampling with a response surface meta-model. These algorithms will be demonstrated on toy examples and on real-world problems in tuberculosis and malaria.
(1) Klein DJ, Baym M, Eckhoff P (2014) The Separatrix Algorithm for Synthesis and Analysis of Stochastic Simulations with Applications in Disease Modeling. PLoS ONE 9(7): e103467. doi: 10.1371/journal.pone.0103467.
(2) Raftery, A. E. & Bao, L (2010). Estimating and Projecting Trends in HIV/AIDS Generalized Epidemics Using Incremental Mixture Importance Sampling. Biometrics 66, 1162–1173.
(3) Klein, D. J., Bershteyn, A. & Eckhoff, P. A. Dropout and re-enrollment: implications for epidemiological projections of treatment programs. AIDS 28, S47–S59 (2014).
Extreme Events in Turbulence: Scaling and Direct Numerical Simulations
Turbulence at high Reynolds numbers is replete with strong fluctuations in vorticity, dissipation and other features of small-scale motion, which can be thousands times their respective mean values. Even at low Reynolds numbers, gradients can be extreme in compressible turbulence where shock waves appear. In order to study these very localized fluctuations in space and time, sufficient resolution (higher than commonly used) is required if all the details are to be captured faithfully in direct numerical simulations (DNS). This poses extraordinary challenges in simulations at high Reynolds or Mach numbers.
Prof. Donzis’ presentation will discuss current computational challenges in simulations using hundreds of thousands of processors as well as a possible path towards simulations at even higher levels of parallelism. He will discuss recent work including results in shock-turbulence interactions, its amplification of turbulence, as well as the modification of the shock.
(1) 2012 Donzis D.A. “Shock structure in shock-turbulence interactions.” Phys. Fluids 20, 126101.
(2) 2012 Yeung P.K., Donzis D.A. & Sreenivasan K.R. “Dissipation, enstrophy and pressure statistics in
turbulence simulations at high Reynolds numbers.” J. Fluid Mech. 700, 5-15.
(3) 2013 Donzis D.A. & Jagannathan S. “On the relation between small-scale intermittency and shocks in
turbulent flows” Procedia IUTAM, 2013, 9, 3-15.
(4) 2014 Donzis D.A., & Aditya K. “Asynchronous finite-difference schemes for partial differential
equations” J. Comp. Phys 274, 370-392.