Applying wireless technologies in control systems can significantly enhance the system mobility and reduce the deployment and maintenance cost. Existing wireless technology standards, however either cannot provide real-time guarantee on packet delivery or are not fast enough to support high-speed control systems which typically require 1kHz or higher sampling rate. Nondeterministic packet transmission and insufficiently high sampling rate will severely hurt the control performance. To address this problem, in this paper, we present our design and implementation of a real-time high-speed wireless communication protocol called RT-WiFi. RT-WiFi is a TDMA data link layer protocol based on IEEE 802.11 physical layer to provide deterministic timing guarantee on packet delivery and high sampling rate up to 6kHz. It incorporates configurable components for adjusting design trade-offs including sampling rate, latency variance, reliability, and compatibility to existing Wi-Fi networks, thus can serve as an ideal communication platform for supporting a wide range of high-speed wireless control systems. We implemented RT-WiFi on commercial off-the-shelf hardware and integrated it into a mobile gait rehabilitation system. Our extensive experiments demonstrate the effectiveness of RT-WiFi in providing deterministic packet delivery in both data link layer and application layer, which further eases the controller design and significantly improve the control performance.

RT-WiFi: Real-Time High-Speed Communication Protocol for Wireless Cyber-Physical Control Applications

Web page loads are slow due to intrinsic inefficiencies in the page load process. Our study shows that the inefficiencies are attributable not only to the contents and structure of the Web pages (e.g., three-fourths of the CSS resources are not used during the initial page load) but also the way that pages are loaded (e.g., 15% of page load times are spent waiting for parsing-blocking resources to be loaded).

To address these inefficiencies, this paper presents Shandian (which means lightening in Chinese) that restructures the page load process to speed up page loads. Shandian exercises control over what portions of the page gets communicated and in what order so that the initial page load is optimized. Unlike previous techniques, Shandian works on demand without requiring a training period, is compatible with existing latency-reducing techniques (e.g., caching and CDNs), supports security features that enforce same-origin policies, and does not impose additional privacy risks. Our evaluations show that Shandian reduces page load times by more than half for both mobile phones and desktops while incurring modest overheads to data usage.

/pdf/speeding-up-web-page-loads-with-shandian-3zag7iequn.pdf

Speeding up web page loads with Shandian

A system creates an application. The system accesses an application development user interface (“UI”) through a browser. The application development UI is hosted by a web-based application development server in a cloud system that provides an application development framework (“ADF”). The system develops the application through the application development UI. The application is developed with the ADF and is configured to be downloaded from a download location in the cloud system. The application is configured to be downloaded on a device as a native application.

Cloud based editor for generation of interpreted artifacts for mobile runtime

A system builds an application. The system receives, by a build server, from an application development server, metadata information of the application and a build request to build the application. The system generates binaries of the application by overlaying the metadata information on binaries of a pre-compiled application. The system then signs the binaries of the application to generate signed binaries of the application, and sends, to the application development server, a corresponding signature and one or more files modified by the signing of the binaries of the application. In one embodiment, the build server stores, on a storage appliance, the corresponding signature, the one or more files modified by the signing of the binaries of the application, and the metadata information of the application.

Efficient storage and transfer of iOS binary files

A system includes download location information in an unprotected Uniform Resource Locator (“URL”), where the download location information identifies a download location for downloading an application provided by a cloud system The system further includes login server information in the unprotected URL, where the login server information identifies a login server that is configured to be logged in before downloading the application from the download location Based on the unprotected URL, the application is configured to be downloaded on a mobile device from the download location and after logging into the login server The application may be developed by accessing a web-based application development server in the cloud system, and after the application is developed, the web-based application development server generates the unprotected URL

Discovery of federated logins

We explore the challenges in expressing and managing concurrency in browsers on mobile devices. Browsers are complex applications that implement multiple standards, need to support legacy behavior, and are highly dynamic and interactive. We present ZOOMM, a highly concurrent web browser engine prototype and show how concurrency is effectively exploited at different levels: speed up computation performance, preload network resources, and preprocess resources outside the critical path of page loading. On a dual-core Android mobile device we demonstrate that ZOOMM is two times faster than the native WebKit based browser when loading the set of pages defined in the Vellamo benchmark.

/pdf/zoomm-a-parallel-web-browser-engine-for-multicore-mobile-1ijgv4r41c.pdf

ZOOMM: a parallel web browser engine for multicore mobile devices

WiFi has been promoted as an affordable technology that can provide broadband Internet connectivity to poor and sparsely populated regions A growing number of deployments, some of substantial scale, are making use of WiFi to extend connectivity into rural areas However, the vast majority of the 35 billion people living in rural villages [1] are still unservedTo reach these people, new technology must be developed to make small rural wireless Internet service providers (WISPs) profitable We have identified radio towers as the largest expense for WISPs; to reduce or eliminate this barrier to entry, we propose a novel point-to-multipoint deployment topology that takes advantage of "natural towers" such as hills and mountains to provide connectivity even over great distances We make this design practical with a new TDMA MAC protocol called JaldiMAC that (i) enables and is optimized for point-to-multipoint deployments, (ii) adapts to the asymmetry of Internet traffic, and (iii) provides loose quality of service guarantees for latency sensitive traffic without compromising fairness To our knowledge, JaldiMAC is the first integrated solution that combines all of these elementsOur evaluation of JaldiMAC suggests that it fulfills its design goals Our scheduler is able to provide a 71% decrease in jitter and superior latency characteristics in exchange for a 5% increase in average RX/TX switches, as compared to a stride scheduler Overall, we find that JaldiMAC performs surprisingly well at this early stage

/pdf/jaldimac-taking-the-distance-further-527i9pm1g8.pdf

JaldiMAC: taking the distance further

Systems and methods enable displaying a graphical representation of system resource usage in a resource utilization map to inform users about system resource utilization by applications and processes running on a computing device. Users may provide inputs to enable the system to adjust resource allocations based on user preferences. This may enable users to improve the overall operational performance of the device consistent with their current personal preferences by identifying applications or processes of most or least interest so the device processor to prioritize system resources accordingly. Some aspects transmit resource allocation data based on such user input to a central server to enable community based resource allocation schemes. Community based resource allocation schemes may be transmitted to computing devices for use as default or preliminary resource allocations for particular applications, websites or device operating states.

Method and apparatus for optimized execution using resource utilization maps

Layered JavaScript engines, in which the JavaScript runtime is built on top another managed runtime, provide better extensibility and portability compared to traditional monolithic engines. In this paper, we revisit the design of layered JavaScript engines and propose a layered architecture, called MuscalietJS2, that splits the responsibilities of a JavaScript engine between a high-level, JavaScript-specific component and a low-level, language-agnostic .NET VM. To make up for the performance loss due to layering, we propose a two pronged approach: high-level JavaScript optimizations and exploitation of low-level VM features that produce very efficient code for hot functions. We demonstrate the validity of the MuscalietJS design through a comprehensive evaluation using both the Sunspider benchmarks and a set of web workloads. We demonstrate that our approach outperforms other layered engines such as IronJS and Rhino engines while providing extensibility, adaptability and portability.

Seth Fowler

Papers

ZOOMM: a parallel web browser engine for multicore mobile devices

JaldiMAC: taking the distance further

Method and apparatus for optimized execution using resource utilization maps

MuscalietJS: rethinking layered dynamic web runtimes