Abstract: A projected memory device includes a carbon-based projection component. The device includes two electrodes, a memory segment, and a projection component. The projection component and the memory segment form a dual element that connects the two electrodes. The projection component extends parallel to and in contact with the memory segment. The memory segment includes a resistive memory material, while the projection component includes a thin film of non-insulating material that essentially comprises carbon. In a particular implementation, the non-insulating material and the projection component essentially comprises amorphous carbon. Using carbon and, in particular, amorphous carbon, as a main component of the projection component, allows unprecedented flexibility to be achieved when tuning the electrical resistance of the projection component.

Abstract: A method of operating a neuromorphic system is provided. The method includes applying voltage signals across input lines of a crossbar array structure, the crossbar array structure including rows and columns interconnected at junctions via programmable electronic devices, the rows including the input lines for applying voltage signals across the electronic devices and the columns including output lines for outputting currents. The method also includes correcting, via a correction unit connected to the output lines, each of the output currents obtained at the output lines according to an affine transformation to compensate for temporal conductance variations in the electronic devices.

Abstract: A memory device enabling a reduced minimal conductance state may be provided. The device comprises a first electrode, a second electrode and phase-change material between the first electrode and the second electrode, wherein the phase-change material enables a plurality of conductivity states depending on the ratio between a crystalline and an amorphous phase of the phase-change material. The memory device comprises additionally a projection layer portion in a region between the first electrode and the second electrode. Thereby, an area directly covered by the phase-change material in the amorphous phase in a reset state of the memory device is larger than an area of the projection layer portion oriented to the phase-change material, such that a discontinuity in the conductance states of the memory device is created and a reduced minimal conductance state of the memory device in a reset state is enabled.

Abstract: A circuit implementing a spiking neural network that includes a learning component that can learn from temporal correlations in the spikes regardless of correlations in the rates. In some embodiments, the learning component comprises a rate-discounting component. In some embodiments, the learning rule computes a rate-normalized covariance (normcov) matrix, detects clusters in this matrix, and sets the synaptic weights according to these clusters. In some embodiments, a synapse with a long-term plasticity rule has an efficacy that is composed by a weight and a fatiguing component. In some embodiments, A Hebbian plasticity component modifies the weight component and a short-term fatigue plasticity component modifies the fatiguing component. The fatigue component increases with increases in the presynaptic spike rate. In some embodiments, the fatigue component increases are implemented in a spike-based manner.

Abstract: The invention is notably directed to a sensor system for performing distributed sensing and classification of sensor data. The sensor system comprises a set of distributed sensor nodes for sensing the sensor data. The sensor system is configured to encode the sensor data of each sensor node of a set of distributed sensor nodes for sensing the sensor data as high-dimensional vectors and to transmit the high-dimensional vectors over a respective link between the respective sensor node and a receiver system. The sensor system is further configured to superpose the high-dimensional vectors of the sensor data from the set of sensor nodes by physical superposition, thereby generating a superposed high-dimensional vector and to classify the superposed high-dimensional vectors at the receiver system.

Abstract: A system for hyper-dimensional computing for inference tasks may be provided. The device comprises an item memory for storing hyper-dimensional item vectors, a query transformation unit connected to the item memory, the query transformation unit being adapted for forming a hyper-dimensional query vector from a query input and hyper-dimensional base vectors stored in the item memory, and an associative memory adapted for storing a plurality of hyper-dimensional profile vectors and for determining a distance between the hyper-dimensional query vector and the plurality of hyper-dimensional profile vectors, wherein the item memory and the associative memory are adapted for in-memory computing using memristive devices.

Abstract: A co-processor for performing a matrix multiplication of an input matrix with a data matrix in one step may be provided. The co-processor receives input signals for the input matrix as optical signals. A plurality of photonic memory elements is arranged at crossing points of an optical waveguide crossbar array. The plurality of memory elements is configured to store values of the data matrix. Input signals are connected to input lines of the optical waveguide crossbar array. Output lines of the optical waveguide crossbar array represent a dot-product between a respective column of the optical waveguide crossbar array and the received input signals, and values of elements of the input matrix to be multiplied with the data matrix correspond to light intensities received at input lines of the respective photonic memory elements. Additionally, different wavelengths are used for each column of the input matrix optical signals.

Abstract: Methods and apparatus are provided for training an artificial neural network having a succession of neuron layers with interposed synaptic layers each having a respective set of N-bit fixed-point weights {w} for weighting signals propagated between its adjacent neuron layers, via an iterative cycle of signal propagation and weight-update calculation operations. Such a method includes, for each synaptic layer, storing a plurality p of the least-significant bits of each N-bit weight w in digital memory, and storing the next n-bit portion of each weight w in an analog multiply-accumulate unit comprising an array of digital memory elements. Each digital memory element comprises n binary memory cells for storing respective bits of the n-bit portion of a weight, where n?1 and (p+n+m)=N where m?0 corresponds to a defined number of most-significant zero bits in weights of the synaptic layer.

Abstract: The present disclosure relates to a method for representing an ordered group of symbols with a hypervector. The method comprises sequentially applying on at least part of the input hypervector associated with a current symbol a predefined number of circular shift operations associated with the current symbol, resulting in a shifted hypervector. A rotate operation may be applied on the shifted hypervector, resulting in an output hypervector. If the current symbol is not the last symbol of the ordered group of symbols the output hypervector may be provided as the input hypervector associated with a subsequent symbol of the current symbol; otherwise, the output hypervector of the last symbol of the ordered group of symbols may be provided as a hypervector that represents the ordered group of symbols.

Abstract: A memory controller circuit for mapping data of a convolutional neural network to a physical memory is disclosed. The memory controller circuit comprises a receiving unit to receive a selection parameter value, and a mapping unit to map pixel values of one layer of the convolutional neural network to memory words of the physical memory according to one of a plurality of mapping schemas, wherein the mapping is dependent on the value of the received selection parameter value.

Abstract: A device for performing a matrix-vector multiplication of a matrix with a vector. The device comprising a memory crossbar array comprising a plurality of row lines, a plurality of column lines and a plurality of junctions arranged between the plurality of row lines and the plurality of column lines. Each junction comprises a programmable resistive element and an access element for accessing the programmable resistive element. The memory crossbar array further comprises one or more write-assist wires and one or more corresponding arrays of switching elements. The write-assist wires are connectable via the switching elements to the plurality of column lines.

Abstract: The present disclosure relates to an electronic system for computing items of an outer product matrix, for each item of at least part of the items of the matrix. The system is configured to receive a pair of real numbers of two vectors, the pair corresponding to the item. The system is further configured to compute a stochastic representation of the real numbers resulting in two sets of bits, the set of bits comprising a subset of bits representing the real number and a sign bit indicative of the sign of the real number. The system is further configured to perform a sequence of digital operations using the two sets of bits to provide a representation of the item.

Abstract: A computer-implemented method for classification of an input element to an output class in a spiking neural network may be provided. The method comprises receiving an input data set comprising a plurality of elements, identifying a set of features and corresponding feature values for each element of the input data set, and associating each feature to a subset of spiking neurons of a set of input spiking neurons of the spiking neural network. Furthermore, the method comprises also generating, by the input spiking neurons, spikes at pseudo-random time instants depending on a value of the feature for a given input element, and classifying an element into a class depending on a distance measure value between output spiking patterns at output spiking neurons of the spiking neural network and a predefined target pattern related to the class.

Abstract: A neuromorphic memory element comprises a memristor, a plurality of the neuromorphic memory elements and a method for operating the same may be provided. The memristor comprises an input signal terminal, an output signal terminal, and a control signal terminal, and a memristive active channel comprising a phase change material. The memristive active channel extends longitudinal between the input signal terminal and the output signal terminal, and a control signal voltage at the control signal terminal is configured to represent volatile biological neural processes of the neuromorphic memory element, and a bias voltage between the input signal terminal and the output signal terminal is configured to represent non-volatile biological neural processes of the neuromorphic memory element.

Abstract: Methods and apparatus are provided for training an artificial neural network, having a succession of neuron layers with interposed synaptic layers each storing a respective set of weights {w} for weighting signals propagated between its adjacent neuron layers, via an iterative cycle of signal propagation and weight-update calculation operations. Such a method includes, for at least one of the synaptic layers, providing a plurality Pl of arrays of memristive devices, each array storing the set of weights of that synaptic layer Sl in respective memristive devices, and, in a signal propagation operation, supplying respective subsets of the signals to be weighted by the synaptic layer Sl in parallel to the Pl arrays. The method also includes, in a weight-update calculation operation, calculating updates to respective weights stored in each of the Pl arrays in dependence on signals propagated by the neuron layers.

Abstract: Methods are provided for training weights of an artificial neural network to be implemented by inference computing apparatus in which the trained weights are stored as programmed conductance states of respective predetermined memristive devices. Such a method includes deriving for the memristive devices a probability distribution indicating distribution of conductance errors for the devices in the programmed conductance states. The method further comprises, in a digital computing apparatus: training the weights via an iterative training process in which the weights are repeatedly updated in response to processing by the network of training data which is propagated over the network via the weights; and applying noise dependent on said probability distribution to weights used in the iterative training process.

Abstract: A circuit implementing a spiking neural network that includes a learning component that can learn from temporal correlations in the spikes regardless of correlations in the rates. In some embodiments, the learning component comprises a rate-discounting component. In some embodiments, the learning rule computes a rate-normalized covariance (normcov) matrix, detects clusters in this matrix, and sets the synaptic weights according to these clusters. In some embodiments, a synapse with a long-term plasticity rule has an efficacy that is composed by a weight and a fatiguing component. In some embodiments, A Hebbian plasticity component modifies the weight component and a short-term fatigue plasticity component modifies the fatiguing component. The fatigue component increases with increases in the presynaptic spike rate. In some embodiments, the fatigue component increases are implemented in a spike-based manner.

Abstract: A memristor memory device comprises a memristive memory cell, an input terminal, an output terminal, and a gate terminal. The input terminal and the output terminal are directly attached to the memristive memory cell, and the gate terminal is electrically isolated from the memristive memory cell. The gate terminal is configured for receiving an electrical signal for a volatile modulation of a conductance of the memristive memory cell, by which a correction of non-ideal conductance modulations of the memristor memory device is achieved.

Abstract: The present disclosure relates to a method for classifying a query information element using the similarity between the query information element and a set of support information elements. A resulting set of similarity scores is transformed using a sharpening function such that the transformed scores are decreasing as negative similarity scores increase and the transformed scores are increasing as positive similarity scores increase. A class of the query information element is determined based on the transformed similarity scores.

Abstract: The present disclosure relates to a method of generating spikes by a neuron of a spiking neural network. The method comprises generating at each time, wherein the spike generation encodes at each time instant at least two variable values at the neuron. Synaptic weights may be optimized for a spike train generated by a given presynaptic neuron of a spiking neural network, wherein the spike train being indicative of features of at least one timescale.