Showing papers on "Offset (computer science) published in 2006"

Rigorous approach to bore-sight self-calibration in airborne laser scanning

Abstract: We present a rigorous method for estimating some of the calibration parameters in airborne laser scanning (ALS), namely the three bore-sight angles and the range-finder offset. The technique is based on expressing the system calibration parameters within the direct-georeferencing equation separately for each target point, and conditioning a group of points to lie on a common surface of a known form such as a plane. However, the assumed a priori information about q chosen planar features is only their form not the spatial orientation or position. Thus, the 4·q plane parameters are estimated together with the calibration parameters in a combined adjustment model that makes use of GPS/INS-derived position and orientation as well as LiDAR range and encoder angle as observations. To make the approach practical when working with voluminous ALS and GPS/INS data, the contribution of each laser point to the normal equations is formed sequentially. The discussions focus on practical examples with data from a continuously-rotating scanner that reveal the conditions under which almost complete de-correlation between the estimated parameters occurs. In such a case, all bore-sight angles are determined with accuracy that is several times superior to the system noise level. Given sufficiently strong geometry, the presented method is shown to be not only accurate but also very robust in terms of convergence. When appropriate, the method is applicable for calibration of additional systematic effects such as laser-beam encoder offsets or scale factor with minimal modification to the functional model.

System and method for enabling de-duplication in a storage system architecture

Abstract: A system and method enables de-duplication in a storage system architecture comprising one or more volumes distributed across a plurality of nodes interconnected as a cluster. De-duplication is enabled through the use of file offset indexing in combination with data content redirection. File offset indexing is illustratively embodied as a Locate by offset function, while data content redirection is embodied as a novel Locate by content function. In response to input of, inter alia, a data container (file) offset, the Locate by offset function returns a data container (file) index that is used to determine a storage server that is responsible for a particular region of the file. The Locate by content function is then invoked to determine the storage server that actually stores the requested data on disk. Notably, the content function ensures that data is stored on a volume of a storage server based on the content of that data rather than based on its offset within a file. This aspect of the invention ensures that all blocks having identical data content are served by the same storage server so that it may implement de-duplication to conserve storage space on disk and increase cache efficiency of memory.

Method for selecting modular implant components

Abstract: A method for selecting modular neck components for hip implants based on independent variables associated with physical characteristics of the implant, including leg length, offset, and anteversion. During surgery, the surgeon may be confronted with a need to change a preoperatively-chosen modular neck. For example, the surgeon may desire a change in at least one of the variables, e.g., leg length, offset, and/or anteversion. The present method allows the surgeon to quickly and easily select a different modular neck based on an evaluation of one of the variables without requiring reevaluation of the other variables. The method may include preoperative planning in which a template including a grid coordinate system is used.

Method for transmitting/receiving data in a communication system

Abstract: Provided is a method for transmitting/receiving data in a communication system providing Multicast/Broadcast Service (MBS). The method includes, generating transmission data to be transmitted to a receiver; allocating the transmission data to a frame; setting a MAP message that includes information on a frame offset related to the frame; and transmitting to the receiver the MAP message.

Optimal periodic training signal for frequency offset estimation in frequency-selective fading channels

Abstract: This paper addresses an optimal periodic training signal design for frequency offset estimation in frequency-selective multipath Rayleigh fading channels. For a fixed transmitted training signal energy within a fixed-length block, the optimal periodic training signal structure (the optimal locations of identical training subblocks) and the optimal training subblock signal are presented. The optimality is based on the minimum Cramer-Rao bound (CRB) criterion. Based on the CRB for joint estimation of frequency offset and channel, the optimal periodic training structure (optimality only in frequency offset estimation, not necessarily in joint frequency offset and channel estimation) is derived. The optimal training subblock signal is obtained by using the average CRB (averaged over the channel fading) and the received training signal statistics. A robust training structure design is also presented in order to reduce the occurrence of outliers at low signal-to-noise ratio values. The proposed training structures and subblock signals achieve substantial performance improvement

Fan array fan section in air-handling systems

Abstract: A fan array fan section in an air-handling system includes a plurality of fan units arranged in a fan array and positioned within an air-handling compartment. One preferred embodiment may include an array controller programmed to operate the plurality of fan units at peak efficiency. The plurality of fan units may be arranged in a true array configuration, a spaced pattern array configuration, a checker board array configuration, rows slightly offset array configuration, columns slightly offset array configuration, or a staggered array configuration.

Optimal training signals for MIMO OFDM channel estimation in the presence of frequency offset and phase noise

Abstract: We develop robust mean-square error (MSE)-optimal training signal designs for multiple-input multiple-output orthogonal frequency-division multiplexing channel estimation with frequency offset and phase noise (PN), and present analytical and simulation results for the frequency-offset and PN effects on channel estimation. The proposed designs are more advantageous for moderate-to-high values of signal-to-noise ratio (SNR), residual frequency offset, and PN level. At SNR = 10 dB, the normalized MSE reductions of our proposed training signals at normalized frequency offset |v|=0.1,0.5 are about 9 and 19 dB, respectively, for one transmit antenna, and 6 and 11 dB for two transmit antennas

An Integrated Subharmonic Coupled-Oscillator Scheme for a 60-GHz Phased-Array Transmitter

Abstract: This paper describes the design of an integrated coupled-oscillator array in SiGe for millimeter-wave applications. The design focuses on a scalable radio architecture where multiple dies are tiled to form larger arrays. A 2 times 2 oscillator array for a 60-GHz transmitter is fabricated with integrated power amplifiers and on-chip antennas. To lock between multiple dies, an injection-locking scheme appropriate for wire-bond interconnects is described. The 2 times 2 array demonstrates a 200 -MHz locking range and 1 times 4 array formed by two adjacent chips has a 60-MHz locking range. The phase noise of the coupled oscillators is below -100 dBc/Hz at a 1-MHz offset when locked to an external reference. To the best of the authors' knowledge, this is the highest frequency demonstration of coupled oscillators fabricated in a conventional silicon integrated-circuit process

Infilling for 2D to 3D image conversion

Abstract: A method for associating a portion of a stereoscopic image with a perceived depth is described. The method includes determining offset values that each indicate a displacement between image data in a first image of a stereoscopic pair and corresponding image data in a second image of the stereoscopic pair. The displacement affects a perceived depth of a point represented by the image data and the corresponding image data. The method also includes identifying image data in the second image that is not associated with a valid offset value, generating a supplementary offset value using valid offset values associated with image data substantially near the image data in the second image, and associating the image data in the second image with the supplementary offset value.

Growth and Location of Economic Activity: The Spatial Dynamics of Industries in Canada 1971–2001

Abstract: A growing literature has accumulated that points to the stability of industrial location patterns. Can this be reconciled with spatial dynamics? This article starts with the premise that demonstrable regularities exist in the manner in which individual industries locate (and relocate) over space. For Canada, spatial distributions of employment are examined for seventy-one industries over a thirty-year period (1971–2001). Industry data is organized by “synthetic regions” based on urban size and distance criteria. “Typical” location patterns are identified for industry groupings. Industrial spatial concentrations are then compared over time using correlation analysis, showing a high degree of stability. Stable industrial location patterns are not, the article finds, incompatible with differential regional growth. Five spatial processes are identified, driving change. The chief driving force is the propensity of dynamic industries to start up in large metro areas, setting off a process of diffusion (for services) and crowding out (for manufacturing), offset by the centralizing impact of greater consumer mobility and falling transport costs. These changes do not, however, significantly alter the relative spatial distribution of most industries over time.

Trimming local and global self-intersections in offset curves/surfaces using distance maps

Abstract: A robust and efficient algorithm for trimming both local and global self-intersections in offset curves and surfaces is presented Our scheme is based on the derivation of a rational distance map between the original curve or surface and its offset By solving a bivariate polynomial equation for an offset curve or a system of three polynomial equations for an offset surface, all local and global self-intersection regions in offset curves or surfaces can be detected The zero-set of polynomial equation(s) corresponds to the self-intersection regions These regions are trimmed by projecting the zero-set into an appropriate parameter space The projection operation simplifies the analysis of the zero-set, which makes the proposed algorithm numerically stable and efficient Furthermore, in a post-processing step, a numerical marching method is employed, which provides a highly precise scheme for self-intersection elimination in both offset curves and surfaces The effectiveness of our approach is demonstrated using several experimental results

A New High Precision Low Offset Dynamic Comparator for High Resolution High Speed ADCs

Abstract: A new low offset dynamic comparator for high resolution high speed analog-to-digital application has been designed. Inputs are reconfigured from the typical differential pair comparator such that near equal current distribution in the input transistors can be achieved for a meta-stable point of the comparator. Restricted signal swing clock for the tail current is also used to ensure constant currents in the differential pairs. Simulation based sensitivity analysis is performed to demonstrate the robustness of the new comparator with respect to stray capacitances, common mode voltage errors and timing errors in a TSMC 0.18? process. Less than l0mV offset can be easily achieved with the proposed structure making it favorable for flash and pipeline data conversion applications.

Estimating sample-domain distortion in the transform domain with rounding compensation

Abstract: Techniques and tools are described for compensating for rounding when estimating sample-domain distortion in the transform domain. For example, a video encoder estimates pixel-domain distortion in the transform domain for a block of transform coefficients after compensating for rounding in the DC coefficient of the block. In this way, the video encoder improves the accuracy of pixel-domain distortion estimation but retains the computational advantages of performing the estimation in the transform domain. Rounding compensation includes, for example, looking up an index (from a de-quantized transform coefficient) in a rounding offset table to determine a rounding offset, then adjusting the coefficient by the offset. Other techniques and tools described herein are directed to creating rounding offset tables and encoders that make encoding decisions after considering rounding effects that occur after an inverse frequency transform on de-quantized transform coefficient values.

Adaptive offset min-sum algorithm for low-density parity check codes

Abstract: An improvement is presented to the offset min-sum decoding algorithm for low-density parity check codes. The proposed algorithm introduces a more efficient adjustment for check-node update computation in view of different minimum values. According to the optimal correction factor of normalized min-sum algorithm, we can determine the adaptive offset item. The improved algorithm achieves a noticeable performance gain with only a modest increase in computation complexity

DC offset correction for direct conversion receivers

Abstract: A direct current (DC) offset correction system for a direct conversion receiver and corresponding receiver and methods facilitate reduction of DC offsets in such receivers. One method includes calibrating a DC offset correction system in a closed loop configuration over each of a plurality of gain settings to provide a plurality of offset data for an operating mode of the direct conversion receiver; selecting one of the plurality of offset data based on a current gain setting of the direct conversion receiver as supplied, e.g., by an AGC system; and operating the DC offset correction system in an open loop configuration using the one of the plurality of offset data to correct for a DC offset in the direct conversion receiver.

Method for correcting a 3D location measured by a tracking system assuming a vertical offset

Abstract: Position measurements by a tracking system associated with a survey tool are corrected for tilt. The tracking station typically incorporates some offset from the surface across which a survey is conducted, and the offset will be subject to angular displacement as the tool tilts with respect to its normal orientation. The tracking system records the 3D position of the survey tool, with angular offset errors. In the disclosed examples, an inertia! measurement unit (IMU), a dual axis inclinometer or a combination of two single axis inclinometers measures the amount of angular offset. The angular offset data is used to correct the position data, e.g. to reduce or eliminate errors caused by the angular offset, e.g. from vertical. If the tool provides measurement data, e.g. GPR readings, processing of the measurement data from the survey tool uses the corrected position data, e.g. to produce images of sub-surface features or objects.

Instant lottery ticket and method

Abstract: A method of manufacturing an improved instant lottery ticket with a graphic overprint applied by offset lithography, and the instant lottery ticket made accordingly, are provided, whereby the superior quality visual images produced by lithographic printing may be obtained for the marketing advantage of the lottery ticket. A substrate comprises a secure area having variable (e.g. game) data printed therein and a graphic area. The secure area is hidden by a non-graphic overprint layer which covers it, comprising scratch-off layers. A graphic overprint layer is applied over the non-graphic overprint layer by means of offset lithographic printing. The non-graphic overprint layer is prepared in such a manner as to provide a sufficiently thin and smooth, and having the appropriate rheology and pH characteristics, for compatibility with graphic overprinting by offset lithography.

Lighting fixture service access

Abstract: Apparatus includes a mounting plate having a hole in a center portion thereof, a recessed light support member having laterally-extending flanges on each of two essentially parallel sides, and a guide disposed on the top surface of the plate, the guide having a longitudinal section offset from the top surface by a distance greater than the thickness of the flanges, where the flanges of the recessed light support member are slidable laterally between the top surface of the plate and the longitudinal section of the guide. A method of servicing a lighting fixture having a can includes sliding the can laterally from a position where the can is centered over the hole to a position where a servicing space is effected between a perimeter of the hole and the can.

Methods and apparatus for determining and/or communicating parameter switching point information in wireless communications systems including wireless terminals supporting multiple wireless connections

Abstract: Methods and apparatus for indicating parameter change points with respect to multiple connections (wireless links) by transmitting a single message, e.g., over one of the connections, is described. A base station corresponding to at least one connection, considers the approximate timing relationship between the connections, selects one of the connections, selects an intended parameter switching point for that connection, determines a symbol time offset from the selected switching point such that the other intended switching points of other wireless links can be unambiguously interpreted by the wireless terminal from information indicating the offset with respect to the selected link, and communicates information indicating the offset and the wireless link to which said offset applies. A wireless terminal receives the information, identifies a time referenced with respect the timing structure of the identified wireless link and then determines individual parameter switching points for the other wireless links.

Synchronous rectifier having precise on/off switching times

Abstract: A synchronous rectifier, including an energy storage element having a terminal; a power supply input, connected to the terminal of the storage element in a first time interval; a reference line connected to the terminal of the storage element in a second time interval; and a zero comparator, coupled to the terminal of the storage element to detect a current flowing in the energy storage element and disconnect the terminal of the storage element from the reference line upon detecting a zero current, the zero comparator having an offset and a propagation time; the zero comparator further having an offset control input and an output. An offset regulating loop is coupled between the output of the zero comparator and the offset control input and regulates the offset of the zero comparator to compensate the propagation time.

Haptic Feedback for UAV Tele-operation - Force offset and spring load modification

Abstract: Haptic feedback is often suggested to complement visual information through the sense of touch to improve efficiency and safety in the tele-operation of unmanned aerial vehicles. It is, however, of great importance that the improvements are not at the cost of higher operator workload and control activity, which strongly depends on how haptic feedback is presented to the operator. This paper describes the study on two different techniques of haptic feedback for collision avoidance in the tele-operation of a UAV helicopter. The first technique considers the addition of an external force offset generated by an artificial force field, whereas the second technique considers the addition of an external spring constant. The study involves a theoretical analysis and an experimental evaluation of the two haptic feedback implementations. Experiment results indicate that the use of the external spring constant outperforms the force offset. Operator performance improves and workload decreases with equivalent control activity and level of safety with respect to the use of force offset.

An Initial Timing Offset Estimation Method for OFDM Systems in Rayleigh Fading Channel

Abstract: An initial timing offset estimation method for orthogonal frequency-division multiplexing (OFDM) systems is proposed. Conventional preamble-based synchronization methods result in performance degradation due to the time variation in the power delay profile of the channel. We propose a simple but efficient synchronization method using a specifically designed preamble. The performance of the proposed estimator is evaluated by computer simulations. The simulation results show that the proposed estimator has a significantly smaller mean squared error (MSE) than other estimators even in the fast varying channel.

Sensor calibration method and apparatus

Abstract: A calibration system for an inertial sensor includes a calibration module for processing an output value produced by the inertial sensor, the output value related to a detected movement of an object, wherein the calibration module calculates an offset value from a plurality of output values, and memory operatively coupled with the calibration module, the memory capable of storing the plurality of output values and/or the offset value, wherein the inertial sensor is calibrated using the calculated offset value.

Method and system for synchronization offset reduction in a TDOA location system

Abstract: A method for reducing synchronization offset errors in a TDOA location finding wireless system, comprising: receiving transmissions from at least one sync unit at multiple location transceivers, wherein the multiple location transceivers are synchronized from the sync unit; determining actual times-of-arrival of the received transmissions in response to receiving transmissions; performing a wireless distance measurement between the transceivers and the at least one sync unit, the wireless distance measurement performed by the transceivers in response to the received transmissions from the at least one sync unit; computing an actual propagation time between the sync unit to the transceivers; computing differences between the actual propagation time and theoretical propagation time determined in conformity with the predetermined locations; estimating synchronization offset error of the transceivers in conformity with the computed differences; and correcting the synchronization offset error.

Offset integrated circuit package-on-package stacking system

Abstract: An offset integrated circuit package-on-package stacking system is provided including providing a base substrate, forming a contact pad on the base substrate, mounting a first integrated circuit on the base substrate, forming a base package body around the first integrated circuit, providing an offset substrate, mounting a second integrated circuit on the offset substrate, and coupling the offset substrate to the contact pad, including placing the offset substrate on the base package body.

Adaptive transmission timing control method, wireless communication system and wireless communication device

Abstract: In a method for adaptive transmission timing control, the overlooking of a base path at the side of the base station that occurs when the transmission timing offset amount changes to the extent of falling outside the current delay-profile calculation range, and the side of the mobile station fails to demodulate the control information that contains the transmission timing offset amount, is prevented. A limit is put on the transmission timing offset amount applied in a single transmission timing control iteration. Together with setting the transmission timing offset value such that the main component of the delay profile calculated from the pilot signal transmitted with offset transmission timing falls within the time range of when the current delay profile was calculated, the time range for calculating the next delay profile is shifted such that a delay profile calculated from the pilot signal transmitted with offset transmission timing falls within the shifted range, starting at the earliest component.

A Point-Based Offsetting Method of Polygonal Meshes

Abstract: We address the delicate problem of offsetting polygonal meshes. Offsetting is important for stereolithography, NC machining, coordinate measuring machines, robot collision avoidance, and Hausdorff error calculation. We introduce a new fast, and very simple method for offsetting (growing and shrinking) a solid model by an arbitrary distance r. Our approach is based on a hybrid data structure combining point samples, voxels, and continuous surfaces. Each face, edge, and vertex of the original solid generates a set of offset points spaced along the (pencil of) normals associated with it. The offset points and normals are sufficiently dense to ensure that all voxels between the original and the offset surfaces are properly labeled as either too close to the original solid or possibly containing the offset surface. Then the offset boundary is generated as the isosurface using these voxels and the associated offset points. We provide a tight error bound on the resulting surface and report experimental results on a variety of CAD models.