We report on chemical vapor deposited (CVD) MoS2radio frequency (RF) transistors with a record fTof 20 GHz and fmaxof 11.4 GHz, and the largest high-field saturation velocity, νsat= 1.88 × 106cm/s, in MoS2reported so far. The gate-first approach, facilitated by cm-scale CVD MoS2, offers enhancement mode operation, ION/IOFFratio of 108, and the highest reported transconductance (gm) of 70 μS/μm. The intrinsic fT(fmax) obtained here is 3X (2X) greater than previously reported top-gated CVD MoS2RF FETs. With as-measured S-parameters, we demonstrate the design of a GHz MoS2-based RF amplifier. This amplifier has gain greater than 15 dB at 1.2 GHz, input return loss > 10 dB, bandwidth > 200 MHz, and DC power consumption of ~10 mW.

Spanner is a globally-distributed data management system that backs hundreds of mission-critical services at Google. Spanner is built on ideas from both the systems and database communities. The first Spanner paper published at OSDI'12 focused on the systems aspects such as scalability, automatic sharding, fault tolerance, consistent replication, external consistency, and wide-area distribution. This paper highlights the database DNA of Spanner. We describe distributed query execution in the presence of resharding, query restarts upon transient failures, range extraction that drives query routing and index seeks, and the improved blockwise-columnar storage format. We touch upon migrating Spanner to the common SQL dialect shared with other systems at Google.

Spanner is Google’s scalable, multiversion, globally distributed, and synchronously replicated database. It is the first system to distribute data at global scale and support externally-consistent distributed transactions. This article describes how Spanner is structured, its feature set, the rationale underlying various design decisions, and a novel time API that exposes clock uncertainty. This API and its implementation are critical to supporting external consistency and a variety of powerful features: nonblocking reads in the past, lock-free snapshot transactions, and atomic schema changes, across all of Spanner.

Access to graphical images (bar charts, diagrams, line graphs, etc.) that are in a tactile form (representation through which content can be accessed by touch) is inadequate for students who are blind and take mathematics, science, and engineering courses. We describe our analysis of the current work practices of tactile graphics specialists who create tactile forms of graphical images. We propose automated means by which to improve the efficiency of current work practices.We describe the implementation of various components of this new automated process, which includes image classification, segmentation, simplification, and layout. We summarize our development of the tactile graphics assistant, which will enable tactile graphics specialists to be more efficient in creating tactile graphics both in batches and individually. We describe our unique team of researchers, practitioners, and student consultants who are blind, all of whom are needed to successfully develop this new way of translating tactile graphics.