Purdue Research Foundation

Nationaluniversity of Ireland, Maynooth

Cold Spring Harbor Laboratory

National University of Ireland

Barak Avrum Pearlmutter

Jeffrey Mark Siskind

Ross O'Neill

Paul O'Grady

Anthony M Zador

A system and method which allows the basic checkpoint-reverse-mode AD strategy (of recursively decomposing the computation to reduce storage requirements of reverse-mode AD) to be applied to arbitrary programs: not just programs consisting of loops, but programs with arbitrarily complex control flow. The method comprises (a) transforming the program into a formalism that allows convenient manipulation by formal tools, and (b) introducing a set of operators to allow computations to be decomposed by running them for a given period of time then pausing them, while treating the paused program as a value subject to manipulation.

System and method for divide-and-conquer checkpointing

An apparatus and method for use in treating tinnitus, employs a sound processing unit, a tactile unit, and an interface therebetween. The tactile unit comprises an array of stimulators each of which can be independently actuated to apply a tactile stimulus to a subject, and an input for receiving a plurality of actuation signals from the interface and directing individual actuation signals to individual stimulators. The sound processing unit receives an audio signal at an input, analyses the signal with a digital signal processor to generate the actuation signals which are representative of the audio signal, and provides the plurality of actuation signals to the interface. In a preferred embodiment the digital signal processor divides the audio signal into a series of frames in the time domain, performs a transform on each frame to generate a set of coefficients representing said frame, and maps the set of coefficients to a set of actuation signals to be applied to the array.

Method and apparatus for sensory substitution

The disclosed system provides a transformation-based implementation of forward-mode and reverse-mode automatic differentiation as a built-in, first-class function in a functional programming language. Each of these constructs imposes only a small constant factor of the computational burden (time) of the function itself, and the forward construct has the same properties in terms of space. The functions can be applied to any function, including those involving derivatives and nested closures.

Automatic derivative method for a computer programming language

The disclosed system provides a functional programming construct that allows convenient modular run-time nonstandard interpretation via reflection on closure environments. This construct encompasses both the ability to examine the contents of a closure environment and to construct a new closure with a modified environment. Examples of this powerful and useful construct support such tasks as tracing, security logging, sandboxing, error checking, profiling, code instrumentation and metering, run-time code patching, and resource monitoring. It is a non-referentially-transparent mechanism that reifies the closure environments that are only implicit in higher-order programs. A further example provides a novel functional-programming language that supports forward automatic differentiation (AD).

Map-closure: a general purpose mechanism for nonstandard interpretation

Systems and methods for performing source separation are provided. Source separation is performed using a composite signal and a signal dictionary. The composite signal is a mixture of sources received by a sensor. The signal dictionary is a database of filtered basis functions that are formed by the application of directional filters. The directional filters approximate how a particular source will be received by the sensor when the source originates from a particular location. Each source can be characterized by a coefficient and a filtered basis function. The coefficients are unknown when the sources are received by the sensor, but can be estimated using the composite signal and the signal dictionary. Various ones of the sources may be selectively reconstructed or separated using the estimated value of the coefficients.

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Barak Avrum Pearlmutter