Randy B. Osborne

Simulating arthroscopic knee surgery using volumetric object representations, real-time volume rendering and haptic feedback

A system for simulating arthroscopic knee surgery that is based on volumetric object models derived from 3D Magnetic Resonance Imaging is presented. Feedback is provided to the user via real-time volume rendering and force feedback for haptic exploration. The system is the result of a unique collaboration between an industrial research laboratory, two major universities, and a leading research hospital. In this paper, components of the system are detailed and the current state of the integrated system is presented. Issues related to future research and plans for expanding the current system are discussed.

Volumetric Object Modeling for Surgical Simulation

Surgical simulation has many applications in medical education, surgical training, surgical planning and intra-operative assistance. However, extending current surface-based computer graphics methods to model phenomena such as the deformation, cutting, tearing or repairing of soft tissues poses significant challenges for real-time interactions. This paper discusses the use of volumetric methods for modeling complex anatomy and tissue interactions. New techniques are introduced that use volumetric methods for modeling soft-tissue deformation and tissue cutting at interactive rates. An initial prototype for simulating arthroscopic knee surgery is described which uses volumetric models of the knee derived from 3-D magnetic resonance imaging, visual feedback via real-time volume and polygon rendering, and haptic feedback provided by a force-feedback device.

EM-Cube: an architecture for low-cost real-time volume rendering

EM-Cube is a VLSI architecture for low-cost, high quality volume rendering at full video frame rates. Derived from the Cube4 architecture developed at SUNY at Stony Brook, EM-Cube computes sample points and gradients on-the-fly to project 3-dimensional volume dnta onto 2-dimensional images with realistic lighting and shading. A modest rendering system based on EM-Cube consists of a PC1 card with four rendering chips (ASICs), four 64Mbit SDRAMs to hold the volume data, and four SRAMs to capture the rendered image. The performance target for this configuration is to render images from a 25G3 x 16 bit data set at 30 fmmes/sec. The EM-Cube architecture can be scaled to larger volume data-sets and/or higher frame rates by adding additional ASKS, SDRAMs, and SRAMs. This paper addresses three major challenges encountered developing EM-Cube into a pm&al product: exploiting the bandwidth inherent in the SDRAMs containing the volume data, keeping the pin-count between adjacent ASICs at a tractable level, and reducing the on-chip stomge required to hold the intermediate results of rendering.

Parsing the Wall Street Journal with the inside-outside algorithm

We report grammar inference experiments on partially parsed sentences taken from the Wall Street Journal corpus using the inside-outside algorithm for stochastic context-free grammars. The initial grammar for the inference process makes no assumption of the kinds of structures and their distributions. The inferred grammar is evaluated by its predicting power and by comparing the bracketing of held out sentences imposed by the inferred grammar with the partial bracketings of these sentences given in the corpus. Using part-of-speech tags as the only source of lexical information, high bracketing accuracy is achieved even with a small subset of the available training material (1045 sentences): 94.4% for test sentences shorter than 10 words and 90.2% for sentences shorter than 15 words.

A hybrid deposit model for low overhead communication in high speed LANs

This paper presents a new, “hybrid deposit” model for low overhead communication wherein the sender directly deposits messages into the destination user-level memory. The destination address is a function of both sender state and destination state. The motivation is to increase the sender’s role in communication in order to simplify the destination’s role and thus enable fast, low-cost communication interfaces. The model separates data delivery from synchronization so as to enable the optimization of simple data delivery while leaving more difficult synchronization to other mechanisms.

Digital Audio and Video in Industrial Systems

In industrial environments such as power plants, automated factories, sewage treatment facilities, railways, etc., digital audio and video play at least three important roles:, On-line documentation and training. Pre-stored video in documentation databases is typically viewed interactively, both during routine operation and during emergency situations. 9 Monitoring and surveillance. Video cameras posted around plants allow operators to keep track of security and proper operation and to provide a visual record for subsequent auditing and analysis. 9 Sensors for plant control. Video and image processing are being used increasingly in the automated operation of the plant i t se l f for example, in equipment to measure speeds, count objects, search for production flaws, detect wear of machinery, etc. In these kinds of settings, it is often desirable to integrate many different functions into the same network for example, functions or applications with hard real-time requirements, continuous media such as audio and video, functions requiring rapid response, and traditional applications using traditional data protocols such as TCP/IP. At first glance, this may not seem too difficult if one simply dedicates a portion of total network bandwidth to the traffic with hard real-time requirements, then a portion of the remainder to audio and video, etc. However, bandwidth is only one of the resources and problems that must be considered in a complete network system. Because of the widely different communication requirements of these functions, the demands of their traffic characteristics, flow control, constraints, and performance criteria are typically more challenging than they would be in typical local area or office networks with workstations, PCs, client and server machines, etc. In this position paper, we discuss a number of issues regarding industrial networks, digital audio and video in those networks, and implications on current research directions. These are considered in the context of ATM (Asynchronous Transfer Mode) networks having speeds ranging from 100 megabits/second to one gigabit/second.

Extending the Multilisp Sponsor Model to Deal with Intertask Synchronization Side Effects

Speculative computing is a technique to improve the execution time of certain applications by starting some computations before it is known that the computations are required. A speculative computation will eventually become mandatory (i.e. required) or irrelevant (i.e. not required). In the absence of side effects irrelevant computations may be aborted. However, with side effects a computation which is irrelevant for the value it produces may still be relevant for the side effects it performs. One problem that can result is the relevant synchronization problem wherein one computation requires some side effect event (a “relevant synchronization”) to be performed by another computation, which might be aborted, before the first computation can make progress. Another problem that can arise is the preemptive delay problem wherein a computation that will perform some awaited side effect event is preempted by a computation whose importance (e.g. priority) is less than that of computations waiting for the event. In this paper we show how the sponsor model developed for speculative computation in Multilisp can be extended to provide a novel solution to these two problems. The idea is for the computation awaiting some action, such as the production of a value or the release of a semaphore, to sponsor the computation or set of computations that will perform the awaited action. This sponsorship ensures that the awaited action executes, and executes with at least the waiters level of importance. We show how to apply this technique to solve the above problems for several producer/consumer and semaphore applications. The idea extends naturally to other synchronization mechanisms.