Ian N. Robinson

Pattern-addressable memory

The pattern associative memory (PAM), a custom associative memory chip specialized to handle the syntax and associated pattern-matching rules common to a range of symbolic processing applications, is discussed. The applications of particular interest are those in which runtime information is captured in the form of a database of declarative expressions. The structure and functioning of an array of these chips, which forms an associative coprocessor for a workstation are described. PAM implementation is addressed.<<ETX>>

ConnectBoard: A remote collaboration system that supports gaze-aware interaction and sharing

We present ConnectBoard, a new system for remote collaboration where users experience natural interaction with one another, seemingly separated only by a vertical, transparent sheet of glass. It overcomes two key shortcomings of conventional video communication systems: the inability to seamlessly capture natural user interactions, like using hands to point and gesture at parts of shared documents, and the inability of users to look into the camera lens without taking their eyes off the display. We solve these problems by placing the camera behind the screen, where the remote user is virtually located. The camera sees through the display to capture images of the user. As a result, our setup captures natural, frontal views of users as they point and gesture at shared media displayed on the screen between them. Users also never have to take their eyes off their screens to look into the camera lens. Our novel optical solution based on wavelength multiplexing can be easily built with off-the-shelf components and does not require custom electronics for projector-camera synchronization.

Fusion of local appearance with stereo depth for object tracking

Object tracking methods based on stereo cameras, which provide both color and depth data at each pixel, find advantage in separating objects from each other and from background, determining the 3D size and location of objects, and modeling object shape. However, stereo tracking methods to date sometimes fail due to depth image noise, and discard much useful appearance information. We propose augmenting stereo-based models of tracked objects with sparse local appearance features, which have recently been applied with great success to object recognition under pose variation and partial occlusion. Depth data complements sparse local features by informing correct assignment of features to objects, while tracking of stable local appearance features helps overcome distortion of object shape models due to depth noise and partial occlusion. To speed up tracking of many local features, we also use a ldquobinary Gaborrdquo representation that is highly descriptive yet efficiently computed using integral images. In addition, a novel online feature selection and pruning technique is described to focus tracking onto the best localized and most consistent features. A tracking framework fusing all of these aspects is provided, and results for challenging video sequences are discussed.

ConnectBoard: Enabling Genuine Eye Contact and Accurate Gaze in Remote Collaboration

Conventional telepresence systems allow remote users to see one another and interact with shared media, but users cannot make eye contact, and gaze awareness with respect to shared media and documents is lost. In this paper, we describe a remote collaboration system based on a see-through display to create an experience where local and remote users are seemingly separated only by a vertical sheet of glass. Users can see each other and media displayed on the shared surface. Face detectors are applied on the local and remote video streams to introduce an offset in the video display so as to bring the local users face, the local camera, and the remote users face image into collinearity. This ensures that, when the local user looks at the remote users image, the camera behind the see-through display captures an image with the “Mona Lisa effect,” where the eyes of an image appears to follow the viewer. Experiments show that, for one-on-one meetings, our system is capable of capturing and delivering realistic, genuine eye contact as well as accurate gaze awareness with respect to shared media.

Real time asset tracking in the data center

The importance and difficultly of asset tracking make it worthy of attention. We focus on data centers consisting of vertical racks where each rack may accommodate a variety of equipment. We describe an asset tracking system which automatically detects and identifies equipment within rack; has “pinpoint” accuracy, i.e., location resolution equals asset size; relays this information to possibly several management back-ends; includes a back-end application that maintains a location history for all equipment; and uses a visualization tool to display both the current state and the history of deployment.The solution features a flexible architecture that simplifies the connection with both existing and future asset management applications. The architecture supports simple configuration, load balancing, and redundancy. Care has been taken to use widely recognized standards wherever possible.

Enabling genuine eye contact and accurate gaze in remote collaboration

Conventional telepresence systems allow remote users to see one another and interact with shared media and documents, but users cannot make eye contact, and gaze awareness with respect to shared media and documents is lost. In this paper we describe a remote collaboration system based on a see-through display to create an experience where local and remote users are seemingly separated only by a vertical sheet of glass. Users can see each other and media displayed on the shared surface. Face detectors on the local and remote video streams are used to introduce an offset in the video display so as to bring the local users face, the local camera, and the remote users face image into collinearity. This ensures that when the local user looks at the remote users image, the camera behind the see-through display captures an image with the ‘Mona Lisa effect’, where the eyes of an image appears to follow the viewer. Experiments show that our system is capable of capturing and delivering realistic, genuine eye contact as well as accurate gaze awareness with respect to shared media.

Gaze awareness and interaction support in presentations

Modern digital presentation systems use rich media to bring highly sophisticated information visualization and highly effective storytelling capabilities to classrooms and corporate boardrooms. In this paper we address a number of issues that arise when the ubiquitous computer-projector setup is used in large venues like the cavernous auditoriums and hotel ballrooms often used in large scale academic meetings and industrial conferences. First, when the presenter is addressing a large audience the slide display needs to be very large and placed high enough so that it is clearly visible from all corners of the room. This makes it impossible for a presenter to walk up to the display and interact with the display with gestures, gaze, and other forms of paralanguage. Second, it is hard for the audience to know which part of the slide the presenter is looking at when he/she has to look the opposite way from the audience while interacting with the slide material. It is also hard for the presenter to see the audience in these cases. Even though there may be video captures of the presenter, slides, and even the audience, the above factors add up to make it very difficult for a user viewing either a live feed or a recording to grasp the interaction between all the components and participants of a presentation. We address these problems with a novel presentation system which creates a live video view that seamlessly combines the presenter and the presented material, capturing all graphical, verbal, and nonverbal channels of communication. The system also allows the local and remote audiences to have highly interactive exchanges with the presenter while creating a comprehensive view for recording or remote streaming.

Components of congestion control

The Fed-X interconnect is a high-speed scalable direct network for a multi-computer system. The switches are connected in a modified wrapped rectangular 2D mesh topology. Each includes a routing device with six half-duplex links providing connections to the adjacent switches. An additional port provides the connection to the local compute node, or PE. hfessages traveling through the interconnect are split into fixed-length packets. The first few words of a standard packet comprise the packet header which contains the source and destination addresses of the packet as well as a umque message and packet identifier. Each half-duplex link alternates directions between the switches on a per-packet basis. Each switch also includes a centralized buffer pool consisting of ten dual-ported, packet-sized buffers. Routing logic decides which port or ports an arriving packet should be forwarded to. If the port is available, the packet re-transmission starts, even if it is still being received. This u~r-tuat cut-through technique minimizes per-hop latenties. If the port is not available the incoming packet accumulates in a switch buffer until the port becomes free. Since the buffer is large enough to absorb the whole packet the link used by the incoming packet can be freed up, even if congestion at the output port persists.

Video cross-talk reduction and synchronization for two-way collaboration

Recent two-way collaboration prototypes attempt to improve natural interactivity, correct eye contact and gaze direction, and media sharing using novel configurations of projectors, screens, and video cameras. These systems are often afflicted by video cross-talk where the content displayed for viewing by the local participant is unintentionally captured by the camera and delivered to the remote participant. Prior attempts to reduce this cross-talk purely in hardware through various forms of multiplexing (e.g., temporal, wavelength (color), polarization) have performance and cost limitations. In this work, careful system characterization and subsequent signal processing algorithms allow us to reduce video cross-talk. The signals themselves are used to detect temporal synchronization offsets which then allow subsequent reduction of the cross-talk signal. Our software-based approach enables the effective use of simpler hardware and optics than prior methods. Results show substantial cross-talk reduction in a system with unsynchronized projector and camera.

R2: A Damped Adaptive Router Design

R2 is an attempt to create an interconnection component that provides reliable packet delivery services at low latency under bursty traffic situations and in the presence of certain faults in either the network or processing elements. The R2 design is based on a damped adaptive routing scheme that avoids livelock, exhibits improved latency under bursty congestion, while performing similar to deterministic strategies in the lightly loaded case. This paper describes the R2 architecture and presents the results of a simulation study which motivates the damped adaptive routing strategy employed by the R2 switch.