Sungwon Nam

Ultrascale Collaborative Visualization Using a Display-Rich Global Cyberinfrastructure

The scalable adaptive graphics environment (SAGE) is high-performance graphics middleware for ultrascale collaborative visualization using a display-rich global cyberinfrastructure. Dozens of sites worldwide use this cyberinfrastructure middleware, which connects high-performance-computing resources over high-speed networks to distributed ultraresolution displays.

Scalable Resolution Display Walls

This article will describe the progress since 2000 on research and development in 2-D and 3-D scalable resolution display walls that are built from tiling individual lower resolution flat panel displays. The article will describe approaches and trends in display hardware construction, middleware architecture, and user-interaction design. The article will also highlight examples of use cases and the benefits the technology has brought to their respective disciplines.

Multi-application inter-tile synchronization on ultra-high-resolution display walls

Ultra-high-resolution tiled-display walls are typically driven by a cluster of computers. Each computer may drive one or more displays. Synchronization between the computers is necessary to ensure that animated imagery displayed on the wall appears seamless. Most tiled-display middleware systems are designed around the assumption that only a single application instance is running in the tiled display at a time. Therefore synchronization can be achieved with a simple solution such as a networked barrier. When a tiled display has to support multiple applications at the same time, however, the simple networked barrier approach does not scale. In this paper we propose and experimentally validate two synchronization algorithms to achieve low-latency, intertile synchronization for multiple applications with independently varying frame rates. The two-phase algorithm is more generally applicable to various highresolution tiled display systems. The one-phase algorithm provides superior results but requires support for the Network Time Protocol and is more CPU-intensive.

Remote visualization of large scale data for ultra-high resolution display environments

ParaView is one of the most widely used scientific tools that support parallel visualization of large scale data. The Scalable Adaptive Graphics Environment (SAGE) is a graphics middleware that enables real-time streaming of ultra-high resolution visual content from distributed visualization resources to scalable tiled displays connected by ultra-high-speed networks. Integrating these two technologies enables visualization of large-scale data at an extremely high resolution to be displayed on distantly located scalable tiled displays. The benefits, limitations, and future directions for this approach will be discussed.

Multiuser-centered resource scheduling for collaborative display wall environments

The popularity of large-scale, high-resolution display walls, as visualization endpoints in eScience infrastructure, is rapidly growing. These displays can be connected to distributed computing resources over high-speed network, providing effective means for researchers to visualize, interact with, and understand large volumes of datasets. Typically large display walls are built by tiling multiple physical displays together and running a tiled display wall required a cluster of computers. With the advent of advanced graphics hardware, a single computer can now drive over a dozen displays, thereby greatly reducing the cost of ownership and maintenance of a tiled display wall system. This in turn enables a broader user base to take advantage of such technologies. Since tiled display walls are also well suited to collaborative work, users tend to launch and operate multiple applications simultaneously. To ensure that applications maintain a high degree of responsiveness to the users even under heavy use loads, the display wall must now ensure that the limited system resources are prioritized to maximize interactivity rather than thread-level fair sharing or overall job-completion throughput. In this paper, we present a new resource scheduling scheme that is specifically designed to prioritize responsiveness in collaborative large display wall environments where multiple users can interact with multiple applications simultaneously. We evaluate our scheduling scheme with a user study involving groups of users interacting simultaneously on a tiled display wall with multiple applications. Results show that our scheduling framework provided a higher frame-rate for applications, which led to a significantly higher user performance (approx. 25%) in a target acquisition test when compared against traditional operating system scheduling scheme. We present a model that prioritizes applications based on how they are presented.We propose a resource scheduling scheme that achieves presentation fairness.User study evaluates the proposed scheduler in a multiuser collaborative session.

Achieving large bandwidth by leveraging parallelism in end-hosts and networks

This paper describes the first experiment on Multi-Rail and MultiLane technologies using global networks. These technologies leverage end-host and network parallel resources, e.g., processor cores and lambda paths, to achieve large bandwidths.

Leveraging end-host parallelism to achieve scalable communication bandwidth utilization

This paper describes experiments to explore the scalability of the MultiRail technology. MultiRail leverages endhost parallel resources to achieve large bandwidth. We confirm that MultiRail scales bandwidth by better utilizing the parallel resources.

Terabit/s-scalable end-to-end parallel networking architecture (TLAN) based on virtual optical resource control

Terabit/s-scalable end-to-end parallel networking architecture (TLAN) based on virtual optical resource control for a high-end scientific application is outlined. Multi-rail- and Multi-lane-aware networking architecture, the relevant photonic technologies, the requirements of optical devices and interfaces for TLAN optical node deployments are also discussed.