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Machine Learning Helps Robot Swarms Coordinate

07-14-20

Soon-Jo Chung, Bren Professor of Aerospace, Yisong Yue, Professor of Computing and Mathematical Sciences, postdoctoral scholar Wolfgang Hönig, and graduate students Benjamin Rivière and Guanya Shi, have designed a new data-driven method to control the movement of multiple robots through cluttered, unmapped spaces, so they do not run into one another. "Our work shows some promising results to overcome the safety, robustness, and scalability issues of conventional black-box artificial intelligence (AI) approaches for swarm motion planning with GLAS and close-proximity control for multiple drones using Neural-Swarm," says Chung. [Caltech story]

Tags: research highlights GALCIT CMS Yisong Yue Soon-Jo Chung postdocs Benjamin Rivière Guanya Shi Wolfgang Hönig

Microstructures Self-Assemble into New Materials

03-03-20

A new process developed at Caltech makes it possible for the first time to manufacture large quantities of materials whose structure is designed at a nanometer scale—the size of DNA's double helix. Pioneered by Professor Julia R. Greer, "nanoarchitected materials" exhibit unusual, often surprising properties—for example, exceptionally lightweight ceramics that spring back to their original shape, like a sponge, after being compressed. Now, a team of engineers at Caltech and ETH Zurich have developed a material that is designed at the nanoscale but assembles itself—with no need for the precision laser assembly. "We couldn't 3-D print this much nanoarchitected material even in a month; instead we're able to grow it in a matter of hours," says Carlos M. Portela, Postdoctoral Scholar. "It is exciting to see our computationally designed optimal nanoscale architectures being realized experimentally in the lab," says Dennis M. Kochmann, Visiting Associate. [Caltech story]

Tags: APhMS research highlights GALCIT MCE Julia Greer Dennis Kochmann postdocs Carlos Portela

Anandkumar Training Algorithms to Spot Online Trolls

01-09-20

Professor Anima Anandkumar, and research team have demonstrated that machine-learning algorithms can monitor online social media conversations as they evolve, which could one day lead to an effective and automated way to spot online trolling. "It was an eye-opening experience about just how ugly trolling can get. Hopefully, the tools we're developing now will help fight all kinds of harassment in the future," says Anandkumar. The research team includes Professor Michael Alvarez; Anqi Liu, postdoctoral scholar; Maya Srikanth, student; and Nicholas Adams-Cohen, Stanford University. [Caltech story]

Tags: research highlights CMS Animashree Anandkumar postdocs Anqi Liu Maya Srikanth

How Electrons Break the Speed Limit

12-10-19

Marco Bernardi, Assistant Professor of Applied Physics and Materials Science, and Jinjian Zhou, Postdoctoral Scholar, have developed a way to predict how electrons interacting strongly with atomic motions will flow through a complex material. "Using a new method, we have been able to predict both the formation and the dynamics of polarons in strontium titanate. This advance is crucial since many semiconductors and oxides of interest for future electronics and energy applications exhibit polaron effects," says Bernardi. [Caltech story]

Tags: APhMS research highlights Marco Bernardi postdocs Jinjian Zhou

Best Paper Award

10-30-19

Postdoctoral Scholar Carlos M. Portela, working with Professor Julia Greer and Dennis Kochmann, has won the Gold Paper Award. The title of the paper is "Supersonic Impact on Carbon Nano-architected Materials." The award was granted to the best student contribution across all topic areas at the Society of Engineering Science (SES) 56th Technical Meeting.

Tags: APhMS honors Julia Greer Dennis Kochmann postdocs Carlos Portela

Jing Li Receives AAAR Sheldon Friedlander Award

10-28-19

Jing Li, a postdoctoral scholar working with Professor Michael R. Hoffmann, is the recipient of the 2019 Sheldon K. Friedlander Award from the American Association of Aerosol Research (AAAR). The award recognizes an outstanding dissertation by an individual who has earned a doctoral degree in any discipline related to the physical, biomedical or engineering sciences in the field of aerosol science and technology. In her doctoral thesis, Jing focused on studying the global PM-borne biologicals and their toxicity, more broadly in bioaerosol field. Her dissertation work raises the awareness of airborne transmission of antibiotic resistance genes (ARGs), as well as global differences of local source-specific PM toxicity. [Past recipients]

Tags: honors ESE Michael Hoffmann postdocs Jing Li

Lasers Aim to Replace Scalpels in Cutting-Edge Biopsy Technique

05-16-19

Professor Lihong Wang and Postdoctoral Scholar Dr. Junhui Shi have developed a new imaging technique that uses pulses from two kinds of lasers to take pictures of microscopic biological structures. This new approach, called ultraviolet-localized mid-infrared photoacoustic microscopy, or ULM-PAM, develops images of the microscopic structures found in a piece of tissue by bombarding the sample with both infrared and ultraviolet laser light. "Because ultraviolet light and infrared have different properties, we had to find special mirrors and glass that could focus both," Dr. Shi says. "And because no camera exists that can see both, we had to develop ways to see if they were correctly focused." [Caltech story]

Tags: EE research highlights MedE Lihong Wang postdocs Junhui Shi

Levitating Objects with Light

03-18-19

Ognjen Ilic, postdoctoral scholar in Professor Harry Atwater’s laboratory, and colleagues have designed a way to levitate and propel objects using only light, by creating specific nanoscale patterning on the objects' surfaces. "We have come up with a method that could levitate macroscopic objects," says Professor Atwater, who is also the director of the Joint Center for Artificial Photosynthesis. "There is an audaciously interesting application to use this technique as a means for propulsion of a new generation of spacecraft. We're a long way from actually doing that, but we are in the process of testing out the principles." [Caltech story]

Tags: APhMS research highlights Harry Atwater postdocs Ognjen Ilic

Best Paper Award

03-13-19

Professor Pietro Perona along with Caltech alumni David Hall and Steve Branson have won the 2018 U. V. Helava Best Paper Award from the ISPRS Journal of Photogrammetry and Remote Sensing. Their paper “From Google Maps to a fine-grained catalog of street trees” was selected for the award. The jury described the work in the paper as “innovative, and applicable for large areas of tree classification and inventories. The developed methodology would affect practices of urban tree management globally.” [Read the paper]

Tags: EE honors Pietro Perona alumni postdocs David Hall Steve Branson

Microscopic Devices That Control Vibrations Could Allow Smaller Mobile Devices

12-12-18

Chiara Daraio, Professor of Mechanical Engineering and Applied Physics, and colleagues have developed phononic devices that include parts that vibrate extremely fast, moving back and forth up to tens of millions of times per second. The devices were developed by creating silicon nitride drums that are just 90 nanometers thick. The drums are arranged into grids, with different grid patterns having different properties. Professor Daraio, along with former Caltech postdoctoral scholar Jinwoong Cha, have shown that arrays of these drums can act as tunable filters for signals of different frequencies and can act like one-way valves for high-frequency waves. [Caltech story]

Tags: research highlights Chiara Daraio MCE APh postdocs Jinwoong Cha