Operating unprotected network links for international collaboration between research and education communities, subject to a high-availability production service requirement, is challenging. Provisioning circuits, maintaining a loop-free network topology, and configuring multipath redundancy to provide high availability are complex processes, which involve extensive coordination between, and manual configuration operations carried out by, multiple network operators, resulting in high operations costs. Moreover, network-oriented research applications increasingly require the capability to program network functions to satisfy particular requirements, such as high tolerance, low delay, end-to-end visibility, etc. We describe a solution, based on Software-Defined Networking (SDN), which significantly lowers the operations costs by automating most network operations and reducing coordination efforts between network operators. The design of the network, before and after SDN was deployed, is discussed. For each network function migrated to SDN, a comparative analysis is provided with metrics, first to represent real measurements before and after each SDN deployment scenario, and second, to describe findings of reduced operations costs.

Languages that lack static typing are ubiquitous in the world of mobile and web applications. The rapid rise of larger applications like interactive web GUIs, games, and cryptography presents a new range of implementation challenges for modern virtual machines to close the performance gap between typed and untyped languages. While all languages can benefit from efficient automatic memory management, languages like JavaScript present extra thrill with innocent-looking but difficult features like dynamically-sized arrays, deletable properties, and prototypes. Optimizing such languages requires complex dynamic techniques with more radical object layout strategies such as dynamically evolving representations for arrays. This paper presents a general approach for gathering temporal allocation site feedback that tackles both the general problem of object lifetime estimation and improves optimization of these problematic language features. We introduce a new implementation technique where allocation mementos processed by the garbage collector and runtime system efficiently tie objects back to allocation sites in the program and dynamically estimate object lifetime, representation, and size to inform three optimizations: pretenuring, pretransitioning, and presizing. Unlike previous work on pretenuring, our system utilizes allocation mementos to achieve fully dynamic allocation-site-based pretenuring in a production system. We implement all of our techniques in V8, a high performance virtual machine for JavaScript, and demonstrate solid performance improvements across a range of benchmarks.

In this paper we introduce multidimensional visualization and interaction techniques that are an extension to related work in parallel histograms and dynamic querying. Bargrams are, in effect, histograms whose bars have been tipped over and lined up end-to-end. We discuss affordances of parallel bargrams in the context of systems that support consumer-based information exploration and choice based on the attributes of the items in the choice set. Our tool called EZChooser has enabled a number of prototypes in such domains as Internet shopping, investment decisions, college choice, and so on, and a limited version has been deployed for car shopping. Evaluations of the techniques include an experiment indicating that trained users prefer EZChooser over static tables for choice tasks among sets of 50 items with 7-9 attributes.