ABSTRACT: Wayne Rosing had a vision of building a global array of telescopes, all networked together and operating as a single integrated observatory, to study objects in the sky that change or move or explode. Objects can be observed continuously; discovery of a sudden event can trigger a telescope anywhere in the world to point and begin an observation.

Wayne founded Las Cumbres Observatory (LCO) as a non-profit corporation in 2005 and the organization spent the ensuing years designing, building, and now operating the network that he envisioned. With Wayne’s investment, LCO has built a unique observatory that is not bound by conventional approaches to operations or observing. Las Cumbres is a unique facility in astronomy, consisting of over 20 fully robotic telescopes at six sites around the world, operating as one automatically scheduled, rapid response network.

On August 17, 2017, for the first time in history, gravitational waves generated by two merging neutron stars were detected on Earth. An alert was sent to astronomers across the globe. Las Cumbres Observatory telescopes were one of the first to capture the flash from the "kilonova" explosion accompanying the merger, marking the first time ever that gravitational waves and light were detected from the same event. LCO's new way of looking at the sky proved critical for deciphering the light from the first kilonova, providing new scientific insights from the scale of atomic nuclei, to the expansion of the Universe as a whole.

Astronomer Iair Arcavi, who led the Las Cumbres Observatory gravitational wave response team, will present this revolutionary discovery and describe how it is ushering in ​a new era in astronomy.

About the speakers:

Wayne Rosing served as vice president of engineering at Google from January 2001 to May 2005.​ ​As a hobby throughout his career, Rosing built telescopes, telescope control systems, and ground telescope mirrors.​ ​In 2005, Rosing founded Las Cumbres Observatory Global Telescope Network.

Iair (pronounced "ya-eer") Arcavi is a NASA Einstein Postdoctoral Fellow at the University of California Santa Barbara. He earned a Bachelor's degree in Physics and Mathematics at Tel Aviv University and a Master's and PhD in Astrophysics at the Weizmann Institute of Science. Iair has been using the robotic telescopes of Las Cumbres Observatory to catch fleeting astronomical events such as exploding supernovae, stars torn apart by supermassive black holes, and most recently, the first flare ever detected from merging neutron stars.

ABSTRACT: This Tech Talk presents the Paxos algorithm and discusses a fictional distributed storage system (i.e. simplified Megastore) based on Paxos.

The Paxos algorithm is one of the most common consensus algorithms. Consensus algorithms are one of the mechanisms that allow satisfying consistency constraints in distributed systems with consistency constraints, whether they follow a leader-replica schema or a peer-to-peer schema.

Leader-replica systems consist of a leader node that proposes, manages, accepts, and serializes changes, and replica nodes that propose changes to the current leader node. Given that a single entity is in charge of acception and serialization, leader-replica systems do not require consensus algorithms in order to agree on what the next state is. However, if the leader node becomes unreachable, the replica nodes need to agree on which one should become the next leader node, and they usually run consensus algorithms to reach that agreement.

Peer-to-peer systems consist of nodes that can propose changes and participate in accepting changes. The nodes need to agree on what the next state is in order to establish consistency, and they usually run consensus algorithms to reach that agreement.

SREs within and outside Google work with highly scalable (and therefore distributed) systems that have consistency constraints and involve consensus algorithms.

About the Speaker: Luis Quesada Torres is a Senior Software Engineer in Google's Site Reliability Engineering team.

Talks from visiting speakers on Algorithms, Theory, and Optimization

Talks from visiting speakers on Algorithms, Theory, and Optimization

ABSTRACT: Co-design research with children is a field that continues to find new ground and expand as it explores new, and more effective ways to design. As children become more enveloped in a world of technology and video games, it follows to leverage these kinds of experiences for use in our design toolbox. In addition, continuing to explore how to include a larger global audience through distributed co-design can advance the design process. This talk focuses on our experiences at the University of Baltimore in trying to develop new ways to work with more children by focusing on those that live in Baltimore City.

ABSTRACT: Many pieces of data have invariants that are not encoded in their type. Validity based testing involves making those invariants explicit and making (property) tests involving those types easy and general by providing very general testing combinators. More info here: https://github.com/NorfairKing/validity

Presented by Tom Sydney Kerckhove, Software Engineer at FP Complete

Gophers Zürich Meetup https://www.meetup.com/Zurich-Gophers/
Includes images by:
- History Channels (A&E Networks) ([1].) [Public domain], via Wikimedia Commons
- Gophers by Renée French

Talks from visiting speakers on Algorithms, Theory, and Optimization

Talks from visiting speakers on Algorithms, Theory, and Optimization

Talks from visiting speakers on Algorithms, Theory, and Optimization

ABSTRACT: Sidewalks form the fabric of urban life, connecting nearly every kind of travel and mode of transportation. As individual travelers, we present varied information requirements about the pedestrian environment consisting of static and transient attributes of the sidewalks ranging from elevation changes to curb ramps to transient surface conditions. Surprisingly, such data, and even the location of sidewalks, are generally unavailable in a user-consumable format.

Equitable pedestrian wayfinding is crucial for a barrier-free city, where people with different abilities can independently access customized, relevant, and up-to-date routing information along pedestrian paths. However, existing routing solutions are rarely aware of sidewalks as data entities and primarily optimize for distance, offering inappropriate routes, for instance, with steep inclines that are unusable by many manual wheelchair users. A data model for equitable pedestrian wayfinding must flexibly support an annotated pedestrian network: a connected graph model that represents sidewalk segments and the way they connect and that can be visualized and populated with data to parameterize a personal cost function. With adequate data, we are able to model navigation behavior and wayfinding among people with disabilities, and build generalized models for non-motorized behavior in pedestrian travel networks. To address these challenges, the Taskar Center for Accessible Technology at the Paul G. Allen School engages with and co-designs solutions with accessibility advocacy groups, data scientists, and academics. Anat Caspi will present a set of tools and applications we have developed under the OpenSidewalks and AccessMap projects that enable custom pedestrian routing and improved infrastructure investment in urban planning.

About the speaker:

Dr. Anat Caspi is Director of the Taskar Center for Accessible Technology (TCAT) whose mission is to develop, translate, and deploy technology that improves quality of life for individuals with diverse mobility and speech abilities. The TCAT projects presented here focus on improving mobility options and access to commuting options for individuals of all abilities. Caspi directs accessible technology projects at the Paul G. Allen School along with collaborations with other departments at the University of Washington. Caspi’s research interests are in the areas of ubiquitous sensing and computing, and applications of machine learning in Data Science for Social Good. Caspi is particularly interested in ways in which collaborative commons and community cooperation can challenge and transform the current economics of assistive technology and incentivize rapid development and deployment of equitably- and inclusively designed technology. Caspi is currently helping to evolve and scale the inclusive design curriculum at the Paul G. Allen School of Computer Science & Engineering. Caspi received a B.S. with Honors and M.S. in Computer Science from Stanford University; she received a Ph.D. in Bioengineering from the joint graduate group in BioE at the University of California at Berkeley and San Francisco. Caspi is the 2017 recipient of Northwest Access Fund Innovation Award, recognizing her contribution and development of products that have improved the quality of life for individuals with a disability in the Pacific Northwest region.

ABSTRACT: I would like to give an introductory intuitive explanation of the Java Memory Model. If you've ever wanted to know the memory ordering guarantees in Java, this talk is for you. Learn about when Java does and doesn't synchronize; volatiles, finals, acquire/release, and more. Plus, a few compiler optimizations that might surprise you.

Speaker Info:
Igor Murashkin: ART engineer -- compiler and runtime team for the Java Language on Android.