Showing papers on "Offset (computer science) published in 2004"

Non-volatile memory and method with bit line compensation dependent on neighboring operating modes

Abstract: When programming a contiguous page of memory storage units, every time a memory storage unit has reached its targeted state and is program-inhibited or locked out from further programming, it creates a perturbation on an adjacent memory storage unit still under programming. The present invention provides as part of a programming circuit and method in which an offset to the perturbation is added to the adjacent memory storage unit still under programming. The offset is added as voltage offset to a bit line of a storage unit under programming. The voltage offset is a predetermined function of whether none or one or both of its neighbors are in a mode that creates perturbation, such as in a program inhibit mode. In this way, an error inherent in programming in parallel high-density memory storage units is eliminated or minimized.

Highly parallel volumetric imaging with a 32-element RF coil array.

Abstract: The improvement of MRI speed with parallel acquisition is ultimately an SNR-limited process. To offset acquisition- and reconstruction-related SNR losses, practical parallel imaging at high accelerations should include the use of a many-element array with a high intrinsic signal-to-noise ratio (SNR) and spatial-encoding capability, and an advantageous imaging paradigm. We present a 32-element receive-coil array and a volumetric paradigm that address the SNR challenge at high accelerations by maximally exploiting multidimensional acceleration in conjunction with noise averaging. Geometric details beyond an initial design concept for the array were determined with the guidance of simulations. Imaging with the support of 32-channel data acquisition systems produced in vivo results with up to 16-fold acceleration, including images from rapid abdominal and MRA studies.

Offset compensation in comparators with minimum input-referred supply noise

Abstract: The resolution of a comparator is determined by the dc input offset and the ac noise. For mixed-mode applications with significant digital switching, input-referred supply noise can be a significant source of error. This paper proposes an offset compensation technique that can simultaneously minimize input-referred supply noise. Demonstrated with digital offset compensation, this scheme reduces input-referred supply noise to a small fraction (13%) of one least significant bit (LSB) digital offset. In addition, the same analysis can be applied to analog offset compensation.

Interspersed training for turbo coded modulation

Abstract: A communications system, having a combination Reed-Solomon encoder and a Turbo-Code encoder Data frame configuration which may be changed to accommodate embedded submarkers of known value are embedded in with the data order to aid synchronization in the receiver system, by providing strings of known symbols. The string of known symbols may be the same as the symbols within a training header that appears at the beginning of a data frame. Frame parameters may be tailored to individual users and may be controlled by information pertaining to receivers, such as bit error rate, of the receiver. Additional headers may be interspersed within the data in order to assist in receiver synchronization. Frames of data may be acquired quickly by a receiver by having a string of symbols representing the phase offset between successive header symbols in the header training sequence in order to determine the carrier offset. Phase lock to a signal may achieved after determining carrier offset in receivers by correlating successive symbols in successive headers. It is emphasized that this abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or the meaning of the claims.

Dual-polarization antenna array

Abstract: An improved antenna array, having at least two groups of individual antenna elements comprising a dipole square and/or patch antenna elements with a square antenna element structure. Individual antenna element arranged at least horizontally offset with respect to one another are provided for each of the two polarizations which are at right angles to one another. At least two additional antenna elements are horizontally offset with respect to one another, and/or at least two pairs of vertically aligned individual antenna elements, which are arranged with a horizontal offset with respect to one another, are provided for each of the two orthogonal polarizations. The individual antenna elements which are in each case arranged with a horizontal offset with respect to one another and are aligned parallel to one another are fed with different phase angles as a function of the depression angle.

An FFT-based method to evaluate and compensate gain and offset errors of interleaved ADC systems

Abstract: Interleaved analog-digital converter (ADC) systems can be used to increase the sampling rate for a given ADC implementation technique. In theory, the maximum sampling rate that can be achieved is limited only by the bandwidth and the practical limits related to the power and space of integrated circuits. In this paper, a solution to increase the sampling rate of a digitizing system based on interleaved ADCs is presented. An error analysis, which takes into consideration offset and gain errors of the different ADC channels, is performed in order to quantify the effect of such errors in the system's performance. A software method based on the fast Fourier transform is presented for offset and gain error compensation of interleaved ADC associations. Numerical simulations and experimental results are used to validate the theory and the proposed compensation algorithm.

Image shifting apparatus for enhanced image resolution

Abstract: An image shifting apparatus may capture multiple frames of an image, with each frame offset by a sub-pixel offset distance. After capture, the various sub-pixel offset images may be registered together and analyzed using known resolution enhancement algorithms. Super resolution algorithms, for example. may take the various frames and perform edge identification and peak extraction routines to improve the resolution of high frequency data within an image. The image shifting apparatus may include an actuation controlled optical compensator within the imaging system that may be adjusted to create a sub-pixel offset image of an original reference image. The optical compensator may be an image-stabilizing element, for example, capable of forming sub-pixel shifts in an image plane.

Method, apparatus and system for handling unreliable feedback information in a wireless network

Abstract: The present invention provides a method, apparatus and system for handling unreliable feedback information in a wireless network. The present invention adjusts one or more communications (202) with a receiving unit (272) in a wireless communication network by receiving feedback information (302) relating to the receiving unit (102), determining a feedback information offset for the receiving unit (272), and adjusting the one or more communications (202) with the receiving unit (272) based on the feedback information and the feedback information offset (306).

Microelectronic package comprising offset conductive posts on compliant layer

Abstract: A microelectronic package includes a mounting structure, a microelectronic element associated with the mounting structure, and a plurality of conductive posts physically connected to the mounting structure and electrically connected to the microelectronic element. The conductive posts project from the mounting structure in an upward direction, at least one of the conductive posts being an offset post. Each offset post has a base connected to the mounting structure, the base of each offset post defining a centroid. Each offset post also defines an upper extremity having a centroid, the centroid of the upper extremity being offset from the centroid of the base in a horizontal offset direction transverse to the upward direction. The mounting structure is adapted to permit tilting of each offset post about a horizontal axis so that the upper extremities may wipe across a contact pad of an opposing circuit board.

Method and Computer Program Product for Finding the Longest Common Subsequences Between Files with Applications to Differential Compression

Abstract: A differential compression method and computer program product combines hash value techniques and suffix array techniques. The invention finds the best matches for every offset of the version file, with respect to a certain granularity and above a certain length threshold. The invention has two variations depending on block size choice. If the block size is kept fixed, the compression performance of the invention is similar to that of the greedy algorithm, without the expensive space and time requirements. If the block size is varied linearly with the reference file size, the invention can run in linear-time and constant-space. It has been shown empirically that the invention performs better than certain known differential compression algorithms in terms of compression and speed.

System of four distance sensors for high-accuracy measurement of topography

Abstract: A novel sensor system consisting of four distance sensors is proposed for the scanning measurement of topography. The system achieves high accuracy and allows high lateral resolution. The configuration of the system can be chosen such that it guarantees perfect reconstruction of the topography in the presence of offset and pitch errors of the scan system provided the sensor measurements are error-free. Moreover, a favorable propagation of the random and systematic errors of the sensor measurements is achieved. The error influences are investigated and the sensor system is compared to a previously proposed three-sensor system by analyzing simulated data.

Method to minimize compatibility error in hierarchical modulation using variable phase

Abstract: The present invention provides a method, receiver and transmitter for use in a SDAR system. The method involves generating a first modulated signal based on first input data. Additional modulation is superimposed on the first modulated signal based on additional input data, being spread across a plurality of symbols in the first modulated signal in a predetermined pattern to generate a modified signal which is then transmitted. The modified signal is decoded by performing a first demodulation of the first modulated signal then additional demodulation is performed to obtain additional input data. The superimposing step uses a plurality of offset sequence values to add the additional modulation to the first modulated signal. The offset sequence may appear as a pseudo-random distribution of offset sequence values, and may include at least one zero offset value. Alternatively, the additional modulated signal may be a fromed as a direct sequence spread spectrum modulation and the offset sequence appearing as a pseudo-noise distribution. A Hadamard matrix sequence may be used as the direct sequence code.

Equal and weighted cost multipath load balancing in a network device

Abstract: A method of mediating the flow of datagrams to a destination in a network is disclosed. The method includes the steps of receiving a datagram at a port of a network device, evaluating a destination address for the datagram based on fields in the incoming packet, searching a longest prefix match (LPM) table using the destination address as a LPM key, determining an address table index and an offset based on entries found in the search of the longest prefix match table, searching an address table using the address table index and the offset as an address key to determine an egress port number of the network device and forwarding the packet based upon at least the egress port number.

Micro pin grid array with wiping action

Abstract: A microelectronic package includes a mounting structure (136), a microelectronic element associated with the mounting structure, and a plurality of conductive posts (146) physically connected to the mounting structure and electrically connected to the microelectronic element. The conductive posts (146) project from the mounting structure (136) in an upward direction (Z), at least one of the conductive posts being an offset post. Each offset post has a base (154) connected to the mounting structure (136), the base of each offset post defining a centroid (156). Each offset post also defines an upper extremity (178) having a centroid (160), the centroid of the upper extremity being offset from the centroid (156) of the base (154) in a horizontal offset direction transverse to the upward direction (Z). The mounting structure (136) is adapted to permit tilting of each offset post about a horizontal axis so that the upper extremities (178) may wipe across a contact pad of an opposing circuit board.

Self-calibration of a rotating camera with a translational offset

Abstract: Camera self calibration, based on a purely rotational movement of the camera, receives the most attention among different camera self-calibration methods due to its algorithmic simplicity. The existing purely rotational methods, however, assume camera rotates around its optical center, therefore yielding no translation offset. This assumption is not realistic, since in practice, the precise location of the optical center is often unknown, and the rotation is often performed about an unknown but fixed point near the optical center. The conventional methods tend to ignore the offset, and therefore, could lead to significant errors with the estimated camera parameters. In this paper, we introduce a new rotation-based camera self-calibration method, which explicitly accounts for the unknown translation offset. To this end, the problem is mathematically formulated and solved for differently taking the translation into consideration. To obtain the camera parameters with unknown camera rotations, our algorithm requires the camera to rotate around an unknown but fixed axis twice, by the same yet unknown angle. This is not an unreasonable assumption for precalibrating a camera on an active head. Experiments with both synthetic and real data show that the systematic errors caused by ignoring the translational offset will be effectively eliminated by our approach.

Auto focus for a flow imaging system

Abstract: A pair of optical gratings are used to modulate light from an object, and the modulated light from either optical is used to determine the velocity of the object. Each optical grating is offset from a reference focal point by the same distance, one grating being offset in a positive direction, the other in a negative direction. Signals produced in response to the modulated light can be processed to determine a direction in which a primary collection lens should be moved in order to improve a focus of the imaging system on the object. The lens is moved incrementally in the direction so determined, and the process is repeated until an optimal focus is achieved. In a preferred embodiment, the signals are weighted, so that the optical grating disposed closest to the optimal focus position contributes the most to velocity detection.

Object recognition using binary image quantization and Hough kernels

Abstract: A system and process for recognizing an object in an input image involving first generating training images depicting the object. A set of prototype edge features is created that collectively represent the edge pixel patterns encountered within a sub-window centered on each pixel depicting an edge of the object in the training images. Next, a Hough kernel is defined for each prototype edge feature in the form of a set of offset vectors representing the distance and direction, from each edge pixel having an associated sub-window exhibiting an edge pixel pattern best represented by the prototype edge feature, to a prescribed reference point on a surface of the object. The offset vectors are represented as originating at a central point of the kernel. For each edge pixel in the input image, the prototype edge feature which best represents the edge pixel pattern exhibited within the sub-window centered on the edge pixel is identified. Then, for each input image pixel location, the number of offset vectors terminating at that location from Hough kernels centered on each edge pixel location of the input image is identified. The Hough kernel centered on each pixel location is the Hough kernel associated with the prototype edge feature best representing the edge pixel pattern exhibited within a sub-window centered on that input image edge pixel location. The object is declared to be present in the input image if any of the input image pixel locations have a quantity of offset vectors terminating thereat that equals or exceeds a detection threshold.

Robust joint frequency offset and channel estimation for OFDM systems

Abstract: We consider the joint carrier frequency offset (CFO) and channel estimation for OFDM systems. A novel frequency offset estimator is derived based on maximum likelihood principles by using the pilot symbols embedded in each OFDM symbol. An iterative joint CFO and channel estimator is proposed to further reduce the estimation error and improve the system performance. The joint estimator is initialized with the first CFO estimate and linearly interpolated channel estimates. The CFO and channel response estimates are updated by maximum likelihood (ML) and least squares (LS) algorithms. Simulation results show that the proposed joint estimator is effective and can achieve excellent bit error rates in just one iteration.

Blind estimation of residual carrier offset in OFDM systems

Abstract: In orthogonal frequency division multiplexing (OFDM) systems, the loss of orthogonality between the subcarriers due to carrier offset can degrade the performance of the system. In the literature, Liu and Tureli proposed a blind, music-like method to solve such a problem. The latter has a good performance as compared to the Cramer-Rao bound, but can have a very high computational complexity. In this letter, based on practical considerations, we present a new implementation of the previous method that reduces significantly the cost without sacrificing the performance.

Self-intersection Removal in Triangular Mesh Offsetting

Abstract: Proposed in this paper is an efficient algorithm to remove self-intersections from the raw offset triangular mesh. The resulting regular mesh can be used in shape inflation, tool path generation, and process planning to name a few. Objective is to find the valid region - set of triangles defining the outer boundary of the offset volume from the raw offset triangular mesh. Starting with a seed triangle, the algorithm grows the valid region to neighboring triangles until it reaches triangles with self-intersection. Then the region growing process crosses over the self-intersection and moves to the adjacent valid triangle. Therefore the region growing traverses valid triangles and intersecting triangles adjacent to valid triangles only. This property makes the algorithm efficient and robust, since this method omits unnecessary traversing invalid region, which usually has very complex geometric shape and contains many meaningless self-intersections.

Joint frequency offset estimation and interference cancellation for MIMO-OFDM systems [mobile radio]

Abstract: Synchronization and equalization in wireless multi-user MIMO-OFDM (multiple-input multiple-output orthogonal frequency division multiplexing) systems is important for next generation wireless communication. This paper proposes a new algorithm for joint frequency offset estimation and equalizer training for the uplink of a multi-user MIMO-OFDM system where each user employs spatial multiplexing. A new two-stage receiver structure is adopted, which consists of an initial space-time equalization for suppressing the co-channel interference (CCI), shortening the channel, and mitigating asynchronicity, followed by parallel equalization and detection in the frequency domain. The effects of frequency offset for each transmit data stream can be adjusted after the space-time equalization. Simulations show good performance in terms of bit error rate and mean square error for the frequency offset estimation.

The design of classical offset Dragonian reflector antennas with circular apertures

Abstract: The vector aperture field of classical offset Dragonian dual-reflector antennas is derived using geometrical-optics concepts. This field then yields the equivalent paraboloid of the geometry. From these results, the conditions for an axially symmetric equivalent paraboloid, when a circular aperture is assumed, are obtained. A complete step-by-step geometrical-optics-based design procedure for optimum classical offset Dragonian antennas with circular apertures is then presented (i.e., zero geometrical-optics cross-polarization and minimum spillover). This procedure is demonstrated by two design examples.

Synchronizing ranging signals in an asynchronous ranging or position system

Abstract: In a local positioning system, the land-based transmitters include free running oscillators or oscillators free of clock synchronization with any remote oscillator. A reference receiver receives the ranging signals from different transmitters and generates timing offset information, such as code phase measurements. The timing offset information is then communicated back to transmitters. The temporal offset information indicates relative timing or phasing of the different transmitted ranging signals to the reference receiver. The transmitters then transmit the temporal offset information with the ranging signals, such as modulating the transmitted code by the timing offset information. A mobile receiver is operable to receive the ranging signals and timing offset information in a same communications path, such as on a same carrier. Position is determined with the temporal offset information and the ranging signals. The temporal offset information for the various transmitters allows the mobile receiver to more accurately determine position than in an unsynchronized system.

Method and apparatus for scheduling asynchronous transmissions

Abstract: The present invention provides a method of scheduling asynchronous transmissions for a plurality of subscriber units. The method includes receiving information associated with a plurality of subscriber units that have uplink data to transmit, the information including uplink timing offset information associated with each of the subscriber units. Two or more subscriber units are then selected from a set of subscriber units having a timing offset differential, that is below a predetermined threshold, where the timing offset differential is the difference between the timing offset of a first subscriber unit and the timing offset of a second subscriber unit further selectively offset by a multiple of the transmission segment size, which minimizes the difference. The transmission segments, which are available for the uplink of data, are then allocated between the selected two or more subscriber units, which limits the number of transmission segments that have at least one of an overlap or a gap, and the amount of any overlap or gap, in order to minimize wasted scheduling opportunities.

Asynchronous local position determination system and method

Abstract: In a local positioning system, the land-based transmitters include free running oscillators or oscillators free of clock synchronization with any remote oscillator. A reference receiver receives the ranging signals from different transmitters and generates timing offset information, such as code phase measurements. The timing offset information is then communicated back to transmitters. The temporal offset information indicates relative timing or phasing of the different transmitted ranging signals to the reference receiver. The transmitters then transmit the temporal offset information with the ranging signals, such as modulating the transmitted code by the timing offset information. A mobile receiver is operable to receive the ranging signals and timing offset information in a same communications path, such as on a same carrier. Position is determined with the temporal offset information and the ranging signals. The temporal offset information for the various transmitters allows the mobile receiver to more accurately determine position than in an unsynchronized system.

Frame rate conversion device, overtaking prediction method for use in the same, display control device and video receiving display device

Abstract: An overtaking prediction method of, when input and output of data to and from a common memory are being performed with an input frame frequency and an output frame frequency made different from each other, predicting a frame in which overtaking occurs between the input and the output of the data to and from the memory. The overtaking prediction method includes a step of predicting the frame in which the overtaking occurs between the input and the output of the data, on the basis of a first parameter corresponding to a difference amount between a progress speed of a write address and a progress speed of a read address and a second parameter corresponding to a difference between a write address and a read address at an overtaking prediction point and to an offset address difference amount between an input offset address and an output offset address.

Enhanced vision system (EVS) processing window tied to flight path

Abstract: A head-up display (HUD) system for an aircraft is disclosed. The HUD comprises a computer receiving information representative of an aircraft flight path. The HUD also comprises a head-up display unit comprising a projector and a combiner. The combiner receives an image from the projector. An imaging sensor is coupled to the computer. The imaging sensor has a pointing direction and a field of view. A region of special processing is defined within the imaging sensor field of view. A program is running on the computer. The program determines an offset for the region of special processing. The offset is based on the aircraft flight path and the imaging sensor pointing direction. The offset is used in the computer to cause display region of special processing to be moved based on the direction of the aircraft flight path.

Azimuth measurement device

Abstract: There is provided an azimuth measurement device capable of not obtaining erroneous offset information when a change is made while maintaining a posture in a particular direction and capable of obtaining corresponding offset information when a change is made in an arbitrary direction. Data from a 3-axis sensor detecting earth magnetism is processed by a data processing unit (19). The processing unit (19) repeatedly, by a predetermined number of times or more, acquires 3-axis output data when the earth magnetism direction has changed in a 3-dimensional space. On the 3-dimensional coordinates having the 3-axis output data as the respective axis components, a coordinate of a position where the irregularities of the distance from the 3-axis output data group is minimum is statistically estimated so as to be used a reference point. According to the coordinate of the reference point, the 3-axis output data offset information is calculated to judge whether the 3-axis output data group is distributed in the vicinity of a particular plane. When the 3-axis output data group is judged to be distributed in the vicinity of a particular plane, the estimation of the coordinate of the reference point is not performed or the estimated coordinate of the reference point is discarded.