This dissertation examines the efforts of journalists to expand their pool of potential sources beyond a group of people often called "the usual suspects." This group consists of public officials, business leaders, experts, spokespeople, and other people who are in the news often. Using interviews, participant observation, a survey, and online ethnography, this research investigates how a growing skepticism of the usual suspects and increasingly powerful technology have led to innovations in the source search process. Some journalists have seen potential in digital search tools, including databases and social media, for finding sources that had once been too difficult or time-consuming to find. Journalists themselves have created two source-finding initiatives: a database called the Public Insight Network, and Storyful, which calls itself the "world's first social news agency." Storyful journalists specialize in finding and verifying social media content from the scenes of breaking news events. Journalists have also used other tools created by public relations professionals and technologists. How did the availability of these tools change the reporting process? It varied by tool, and by journalist. Although the tools were designed to do similar things, journalists used them in different ways. This dissertation examines how journalists used these tools in three stages of the reporting process: finding sources, verifying sources, and managing sources. Ultimately, most journalists used these tools not to find new sources, but to follow and research sources they had already identified by name or location. Few journalists had discovered new sources and story ideas with the help of digital search tools. So while these tools opened new possibilities for finding sources, journalists were still more likely to cover some people and topics over others.

The purpose of this thesis is to explore the design of a multimedia extension Instruction Set Architecture (ISA) for a reconfigurable processor. An Extendable Multimedia Module (EM3) was designed as an optional module for X32V. X32V is a prototype configurable processor simulator developed at Oregon State University by John Mark Matson and Dr. Ben Lee. The EM3 ISA uses Single-Instruction Multiple-Data (SIMD) type instructions to improve the performance of multimedia applications on X32V such as MPEG-4. Two benchmarks based on certain stages of MPEG-4 decompression were developed to test the initial performance enhancements of EM3. The results of these benchmark tests indicate a several fold improvement in clock cycles and the number of instructions executed. This improvement demonstrates the performance increase of X32V and illustrates the effectiveness of SIMD type multimedia extensions. / Graduation date: 2004

In the past, multimedia technology focused mainly on designing high quality audio and graphical imagery as well as providing adequate performance levels that the users demand for multimedia applications. However, the concept of multimedia has expanded into New-Media that involves variety use of multimedia data in consumer-oriented applications, such as video conferencing, virtual reality, and multimedia games with 3-D effect in video and audio. As the demands for multimedia applications increase, vendors have come up with new cost-effective microprocessor designs to satisfy the complexity of new media processing. One of the most efficient methods is to incorporate the special-purpose multimedia processor into a general-purpose processor, thereby offering multimedia-related functions at a small cost. Most effective way to integrate the two different processors is to extend the existing instruction set into a multimedia-oriented Instruction Set Architecture, called Media ISA Extension. Currently, many microprocessor vendors have produced variety of general-purpose processors with multimedia extensions. This thesis aims to provide the overall design philosophy behind Media ISA Extension and its effect on the overall performance of a general-purpose processor. In particular, Sun Microsystems' Visual Instruction Set (VIS) media extension of UltraSPARC-V9 is studied. On the average, VIS provides a speed-up of 3 to 4 for various multimedia applications. This performance improvement comes from the considerable reduction in the number of instructions executed due to Single Instruction Multiple Data (SIMD) execution style of VIS media extensions. To examine how VIS improves multimedia performance, the thesis studies the design concept, benefits and limitations of VIS extensions, and the performance of various multimedia applications with and without VIS extension. Finally, the possible architectural modifications to the VIS extension for further performance enhancement are suggested. / Graduation date: 2000

The multimedia capabilities of computers have recently become the focus of computer developers due to the increasing demand for advanced computer graphics and new media capabilities, such as video conferencing, 3-D visualization, and animation. To support these multimedia capabilities, specialized graphics hardware, such as MPEG encoding/decoding card, 3-D graphics card, video card, and sound card, are widely used today, but the price of a separate board is expensive. Therefore, the processor must be redesigned from the ground up to handle new media applications. Although these multimedia functions are typically consist of simple operations, their sheer volume of computation creates a flood of data. To support such large volumes of multimedia data computation, Sun Microsystems implemented a specialized instruction set, called VIS[Trademark] (Visual Instruction Set), which is Single Instruction Multiple Data (SIMD) style of instruction. The basic concept behind VIS is to break the pipeline of the Floating Point Unit (FPU) into two or four parallel pipelines to perform four or eight separate 16-bit or 8-bit integer additions in one cycle, instead of one floating-point addition. The Electronics and Telecommunications Research Institute (ETRI) in South Korea has researched a 64-bit multimedia enhanced on-chip multiprocessor named Raptor, which has quad processors and shares a common Graphics Control Unit (GCU). Raptor implements multimedia support directly on the processor using specialized instructions, GCU Instructions, which are variant of VIS instructions, and hardware supports. Each processor of Raptor executes multimedia applications independently and the independent streams or threads of multimedia instructions compute for and share a single GCU. The major theme of this thesis is to design the GCU architecture and to simulate it. The GCU can simultaneously execute the independent instruction streams from four General Processors (GP) and resolves the dependencies among the instructions dynamically. / Graduation date: 1998

Thesis (Ph. D.)--Worcester Polytechnic Institute. / Keywords: Playout buffer; rate selection; streaming multimedia; wireless networks; bandwith estimation. Includes bibliographical references (leaves 187-202).

Thesis (Ph. D.)--University of Texas at Austin, 2002. / Vita. Includes bibliographical references. Available also from UMI Company.

Thesis (Ph. D.)--Ohio State University, 2003. / Title from first page of PDF file. Document formatted into pages; contains xvi, 135 p.: ill. Includes abstract and vita. Co-advisors: Wu-Chi Feng, Dong Xuan, Dept. of Computer ad information Science. Includes bibliographical references (p. 129-135).

Cloud computing, which is among the trendiest computing paradigms in recent years, is believed to be most suitable for supporting network-centric applications by providing elastic amounts of bandwidth for accessing a wide range of resources on the y. In particular, geo-distributed cloud systems are widely in construction nowadays. They span multiple data centers at different geographical locations, thus offering many advantages to large-scale multimedia applications because of the abundance of on-demand storage/bandwidth capacities and their geographical proximity to different groups of users. In this thesis, we investigate the common fundamental challenges in how to efficiently leverage the power of cloud resources to facilitate multimedia content delivery in various modern real world applications, from different perspectives. First, from the perspective of application providers, we propose tractable procedures for both model analysis and system designs of supporting representative large scale multimedia applications in a cloud system, i.e., VoD streaming applications and social media applications, respectively. We further verify the effectiveness of these algorithms and the feasibility of their deployment under dynamic realistic settings in real-life cloud systems. Second, from the perspective of end users, we target our focus at mobile users. The rapidly increasing power of personal mobile devices, dwarfing even high-end devices, is providing much richer contents and social interactions to users on the move, and many more challenging applications are on the horizon. We explore the tough challenges of how to effectively exploit cloud resources to facilitate mobile services by introducing two cloud-assisted mobile systems (i.e., CloudMoV and vSky-Conf), and explain in details their design philosophies and implementation. Finally, from the perspective of the cloud providers, we realize existing data center networks lack the flexibility to support many core services, given our hands-on experiences from working with public cloud systems. One of the specific problem is, “bulk data transfers across geo-distributed datacenters". After formulating a novel and well-formed optimization model for treating the data migration problem, we design and implement a Delay Tolerant Migration (DTM) system based on the Beacon platform and standard OpenFlow APIs. The system realizes a reliable Datacenter to Datacenter (D2D) network by applying the software defined networking (SDN) paradigm. Real-world experiments under realistic network traffic demonstrate the efficiency of the design. / published_or_final_version / Computer Science / Doctoral / Doctor of Philosophy

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