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Thu, 28 Jul 2016 20:26:29 GMT
20160728T20:26:29Z

Fieldintensity survey on 49.5 and 99 megacycles
http://hdl.handle.net/1853/55416
Fieldintensity survey on 49.5 and 99 megacycles
Honnell, Martial Alfred
Issued as final report
Wed, 01 Jan 1947 00:00:00 GMT
http://hdl.handle.net/1853/55416
19470101T00:00:00Z
Honnell, Martial Alfred

Lagrangian Duality in 3D SLAM: Verification Techniques and Optimal Solutions
http://hdl.handle.net/1853/55415
Lagrangian Duality in 3D SLAM: Verification Techniques and Optimal Solutions
Carlone, Luca; Rosen, David M.; Calafiore, Giuseppe; Leonard, John J.; Dellaert, Frank
Stateoftheart techniques for simultaneous localization
and mapping (SLAM) employ iterative nonlinear optimization methods to compute an estimate for robot poses. While
these techniques often work well in practice, they do not provide guarantees on the quality of the estimate. This paper shows that Lagrangian duality is a powerful tool to assess the quality of a
given candidate solution. Our contribution is threefold. First, we discuss a revised formulation of the SLAM inference problem. We show that this formulation is probabilistically grounded and has the advantage of leading to an optimization problem with quadratic objective. The second contribution is the derivation of the corresponding Lagrangian dual problem. The SLAM
dual problem is a (convex) semidefinite program, which can be
solved reliably and globally by offtheshelf solvers. The third contribution is to discuss the relation between the original SLAM
problem and its dual. We show that from the dual problem, one can evaluate the quality (i.e., the suboptimality gap) of a
candidate SLAM solution, and ultimately provide a certificate of optimality. Moreover, when the duality gap is zero, one can compute a guaranteed optimal SLAM solution from the dual
problem, circumventing nonconvex optimization. We present extensive (real and simulated) experiments supporting our claims and discuss practical relevance and open problems.
© 2015 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works.; DOI: 10.1109/IROS.2015.7353364
Thu, 01 Jan 2015 00:00:00 GMT
http://hdl.handle.net/1853/55415
20150101T00:00:00Z
Carlone, Luca
Rosen, David M.
Calafiore, Giuseppe
Leonard, John J.
Dellaert, Frank
Stateoftheart techniques for simultaneous localization
and mapping (SLAM) employ iterative nonlinear optimization methods to compute an estimate for robot poses. While
these techniques often work well in practice, they do not provide guarantees on the quality of the estimate. This paper shows that Lagrangian duality is a powerful tool to assess the quality of a
given candidate solution. Our contribution is threefold. First, we discuss a revised formulation of the SLAM inference problem. We show that this formulation is probabilistically grounded and has the advantage of leading to an optimization problem with quadratic objective. The second contribution is the derivation of the corresponding Lagrangian dual problem. The SLAM
dual problem is a (convex) semidefinite program, which can be
solved reliably and globally by offtheshelf solvers. The third contribution is to discuss the relation between the original SLAM
problem and its dual. We show that from the dual problem, one can evaluate the quality (i.e., the suboptimality gap) of a
candidate SLAM solution, and ultimately provide a certificate of optimality. Moreover, when the duality gap is zero, one can compute a guaranteed optimal SLAM solution from the dual
problem, circumventing nonconvex optimization. We present extensive (real and simulated) experiments supporting our claims and discuss practical relevance and open problems.

Data as Wood
http://hdl.handle.net/1853/55414
Data as Wood
Bennett, Charlie; Doshi, Ameet; Hagenmaier, Wendy; Rascoe, Fred
Interview portion of Lost in the Stacks episode 311, broadcast July 22, 2016. Features interview with Nicholas Felton, designer of the Facebook timeline and creator of the Feltron Report. Felton discusses data visualization, information privacy, and the concept of "Data as Wood".
Fri, 22 Jul 2016 00:00:00 GMT
http://hdl.handle.net/1853/55414
20160722T00:00:00Z
Bennett, Charlie
Doshi, Ameet
Hagenmaier, Wendy
Rascoe, Fred
Interview portion of Lost in the Stacks episode 311, broadcast July 22, 2016. Features interview with Nicholas Felton, designer of the Facebook timeline and creator of the Feltron Report. Felton discusses data visualization, information privacy, and the concept of "Data as Wood".

The Effect of Sweep and Taper on Static Performance for Small Propellers
http://hdl.handle.net/1853/55410
The Effect of Sweep and Taper on Static Performance for Small Propellers
Kadri, Tobi
These past few years have been the years of the UAV. UAVs, also called drones, now have the friendly tasks of filming sports or movie scenes, civilian surveillance, and simple general aviation. Some companies see a future where UAVs are delivering pizza or packages. All of this shows a demand for civilian UAVs, typically in the form of quadcopters, but can also be small R/C planes. These aircraft are usually powered by small propellers and the design for propellers has not changed much despite the recent wave of UAV popularity. Two universities have made serious progress in the tabulation of small and micro propeller performance, but the realm of small and micro propeller geometry has not been pursued. Most propellers today are only classified by diameter and pitch, a measure of how far a propeller would “screw” into a solid object but other geometries of the propeller may lead to enhanced performance as well. In this study, seventeen 9 in. propellers were fabricated and tested. Thrust and torque coefficients were plotted against RPM since the tests were conducted statically. Forward sweep has adverse effects on both thrust and torque with only a hint that a higher sweep magnitude might yield significant performance improvements. Aft sweep yields substantial increases in thrust and torque, at the expense of higher power, and should qualify as a viable parameter for propeller manufactures to include in designs. A taper ratio greater than 1 has negligible increases in both thrust and torque while a taper ratio less than 1 has adverse effects on both. Varying taper ratio, at least solely from root to tip, is therefore not an effective strategy for thrust or torque augmentation, however small taper does reduce the induced power for a given thrust.
Mon, 18 Jul 2016 00:00:00 GMT
http://hdl.handle.net/1853/55410
20160718T00:00:00Z
Kadri, Tobi
These past few years have been the years of the UAV. UAVs, also called drones, now have the friendly tasks of filming sports or movie scenes, civilian surveillance, and simple general aviation. Some companies see a future where UAVs are delivering pizza or packages. All of this shows a demand for civilian UAVs, typically in the form of quadcopters, but can also be small R/C planes. These aircraft are usually powered by small propellers and the design for propellers has not changed much despite the recent wave of UAV popularity. Two universities have made serious progress in the tabulation of small and micro propeller performance, but the realm of small and micro propeller geometry has not been pursued. Most propellers today are only classified by diameter and pitch, a measure of how far a propeller would “screw” into a solid object but other geometries of the propeller may lead to enhanced performance as well. In this study, seventeen 9 in. propellers were fabricated and tested. Thrust and torque coefficients were plotted against RPM since the tests were conducted statically. Forward sweep has adverse effects on both thrust and torque with only a hint that a higher sweep magnitude might yield significant performance improvements. Aft sweep yields substantial increases in thrust and torque, at the expense of higher power, and should qualify as a viable parameter for propeller manufactures to include in designs. A taper ratio greater than 1 has negligible increases in both thrust and torque while a taper ratio less than 1 has adverse effects on both. Varying taper ratio, at least solely from root to tip, is therefore not an effective strategy for thrust or torque augmentation, however small taper does reduce the induced power for a given thrust.