Showing papers on "Offset (computer science) published in 1983"

Offset problem and k-incremental predictors in self-tuning control

Abstract: Regulation against offsets such as those induced by load disturbances is a principal requirement in process control, and is commonly achieved by the integral term in the classical PID algorithm. It is important, therefore, that self-tuning controllers attain the same objective along with their useful adaptive property. In an important class of self-tuners based on predictive control theory two problems arise: the well known ‘λ offset’ originating from the weighting placed on control activity and the hitherto little recognised ‘prediction offset’ which stems from possible bias in the prediction of the auxiliary output variable. This bias stems from the estimation of the predictor model in positional form. Various ad hoc solutions have been proposed in the literature, such as inserting a forward-path integrator; the weaknesses in these ideas are explored in the paper. A novel k-incremental predictor is derived which solves the offset problem whilst retaining the other attributes of the self-tuning controller such as its model following performance. A by-product of the predictor is that the estimation becomes better conditioned numerically as it works on zero mean data. Moreover, the design is robust in the sense that the freezing of estimation does not detract from its offset elimination property.

Fracture detection using circumferential offset acoustic paths

Abstract: In the apparatus and method of the invention, acoustic energy is propagated in two slightly differing, or offset, circumferential paths in such a way as to interact with the formation under investigation. The propagating energy is detected and the resulting waveforms are compared using semblance. The waveforms corresponding to the respective paths will be quite similar provided that the length of the paths are equal and that there are no fractures or other similar anomalies between the source and receiver. The waveforms for the respective paths will be quite dissimilar, however, if a fracture or similar anomaly does lie between the source and receiver for the respective paths. The semblance may be displayed in log format.

Delta-sigma pulse modulator with offset compensation

Abstract: A modulator is provided for converting an analog input to an output pulse train having an average amplitude proportional to the input signal. The modulator circuit employs delta-minus-sigma modulation in which the output pulse train controls the selection of reference signals which exactly balance the input signal, over time. Instantaneous differences between the reference signals and the input signal are accumulated and measured by an integrator/comparator circuit. A high level of accuracy is achieved in the integrator/comparator because the system employs offset compensation to correct for voltage offset in one or more of the operational amplifiers. Several embodiments of the offset compensation system are disclosed. A method of modulation is also disclosed.

Memory management system

Abstract: A memory management system for providing memory protection for various programs running in a computer such as a 16-bit multi-tasking computer system. The scheme of the present invention provides address translation so as to provide separation of memory spaces. In this connection, each program in the machine has associated therewith, two numbers including an offset number and a limit number. Each program is written so that its base starting address is at the same predetermined address, preferably zero. The address space for each program is separated in memory by adding the offset number for that program to the base address to provide the physical address number. The program is prevented from accessing any memory area outside of its allotted area by comparing the sum of the offset and processor addresses to the limit number. If the result is less than the limit number, the computed address is valid, and if it is outside the limit number then the computed address is considered invalid and an error routine is initiated.

Application of the tau-p transform (slant-stack) in processing seismic reflection data

Abstract: The tau-p transform, or slant-stack, converts seismic records (i.e. time versus offset records) into a space in which many seismic events are well separated. In particular, ground-roll transforms to a point at time zero, refractions transform to points at their zero offset intercept times and reflection hyperbolae transform to ellipses. Significantly, the ellipses do not cross one another, even if the reflection hyperbolae do cross each other in record space. The tau-p space has different dimensions than conventional record space. Record space can be thought of as traces with units of time and with each trace representing a given offset x. In the tau-p space, tau (in dimensions of time), actually represents zero offset reflection time. Each trace corresponds to a particular ray parameter, p. This parameter p can be thought of in many different ways: it is a ray parameter sin i/v; it is the dt/dx, or the slope of the arriving event; and it is the horizontal slowness of the event across the recordi...

Modal analysis of loss and mode mixing in multimode parabolic index splices

Abstract: In this paper we present an electromagnetic modal theory for characterizing parabolic-index multimode fiber splices with either intrinsic or extrinsic mismatches. The theory agrees with previously published theoretical results for transverse offset using a uniform power distribution. It also agrees with new experimental measurements made with a long, spliced input fiber using a published, theoretical, steady-state modal power distribution. This modal theory predicts, and experiment confirms, a previously unreported periodic fluctuation in splice loss as a function of wavelength for intrinsic parameter mismatch. The analysis also predicts a large degree of mode mixing for transverse offset but negligible mode mixing for parameter mismatch in typical multimode fiber splices.

Program storage hardware with security scheme

Abstract: A computer generally includes a program storage device for storage in memory of program or other information. The software or program may be expensive to produce yet can be copied without undue difficulty from the storage device. This invention provides a program storage device which does not output an address, as part of an instruction, if it is an address within the device. The data output from a programmable read only memory (PROM) is output to a data modifier where in response to a controller it is changed to a dummy address for output. Information to reconstitute the address is held in a stack then when the dummy address returns the controller causes an offset adder to return the original address. Steps can be taken to deal appropriately with conditional instructions and relative instructions.

Efficient computation of the far field of parabolic reflectors by pseudo-sampling algorithm

Abstract: The newly developed pseudo-sampling representation is applied for computing the far field of an offset parabolic reflector with a cluster feed illumination. A new comb-type fast Fourier transform (FFT) algorithm is used in a computer program. Both precision and computational time are analyzed, demonstrating the excellent performance of the method.

Video picture stabilising system

Abstract: A video picture stabilising system wherein a video input from a camera 11 is converted to digital form and stored sequentially in memory 17 starting from a variable address (offset from the beginning of the memory block). The variable offset address is obtained from the motion sensing circuits 10, by an interface unit 14 and is thus determined by the amount of shift of the camera from a mean position. The memory locations are read out sequentially and converted back to analog form, but here the addressing starts at a fixed address, the beginning of the memory block. This introduces a delay and hence offset in the output data. However, this offset is determined by the variable offset address and hence the camera shift or offset from its mean position. Thus, this introduced controllable offset can compensate for the offset introduced into the video picture signal by the shifted camera position. Therefore, the analog output from the complete system when displayed will show the scene without any offset i.e. as if the camera were still at its mean position.

Data processing device

Abstract: PURPOSE:To externally connect a memory having large capacity by adding a means for modifying address data outputted from a microprocessor so as to expand an address space which can be specified by the address data. CONSTITUTION:a microprocessor 100 sets an address data in an offset address register 120 by a writing signal 110. The set offset address data is inputted to an address modifying circuit 140 through an output line. Continuous and physical addresses are assigned to a memory block 150 and these addresses are selected in every bit or every byte by an address on a memory address bus 130. Address operation is executed so as to increase the number of effective addresses on the basis of said offset address data and the address data from the micro-processor and the operated result is supplied to the memory block 150 as an memory address, so that a memory having large capacity can be externally connected.

Synthetic Seismograms With Offset For a Layered Elastic Medium

Abstract: One of the severest problems facing exploration geophysicists is the interpretation of surface seismic data to estimate the physical properties of potential oil and gas zones. Attempts to do this are usually based dominantly on an inspection of CDP stacked seismic sections, in conjunction with well logs, if available. Existing information on the amplitude and character of the seismic response as a function of source to receiver offset is usually overlooked, mainly because it is not directly interpretable in terms of geological or physical properties. In fact, it may not be feasible to tackle this inversion problem competently unless the geophysical interpreter has access to a practical solution of the direct elastic problem, namely the theoretical seismic response with offset of an interpreted geological model. Even with today's computer capabilities, the solution of this direct problem for a complex geologic model is costly. However, the solution can become fast, economical and useful, for a model with horizontal layers only. Illustrative examples, using such a modeling program, are described here and mainly emphasize the possible use of amplitude variations with offset to distinquish a sand-shale sequence from an all shale section. It is believed that this form of elastic modeling maymore » provide a valuable tool for guiding and checking the interpretation of seismic records for stratigraphic oil and gas reservoirs.« less

Late Cenozoic Offset and Uplift Along the San Gregorio Fault Zone: Central California Continental Margin

Abstract: The San Gregorio fault is but one component of a much larger fault zone (San Gregorio-Hosgri) which extends some 400 km from its intersection with the San Andreas fault, north of San Francisco, south to Point Arguello. Right-lateral, strike-slip displacement along the San Gregorio was initiated during the late middle Miocene. Concomitant with this, the Outer Santa Cruz Basin began to develop in response to wrench fault tectonics associated with movement along the San Gregorio fault zone. Total late Cenozoic (post-late middle Miocene) offset along the San Gregorio-Hosgri fault zone has been 105 km, based upon offset of Salinian/Franciscan contacts south of Point Sur and south of Point Ano Nuevo, where the Pigeon Point High terminates along the San Gregorio fault zone. Uplift has occurred during the past 750,000 years along the southeastern end of the Outer Santa Cruz Basin due to convergence of right-lateral , strike-slip faults at the terminus of this fault-wedge basin.

Magnetic disc device

Abstract: PURPOSE:To make a stable seek operation possible by controlling always the current flowed to a voice coil motor to a saturation current or lower even if the length to a target is a prescribed value or longer. CONSTITUTION:The length to a target position is given to start the seel operation, and an output signal is outputted to an offset generating circuit 4 from a discriminating circuit 5 if this length is longer than a prescribed length. The offset generating circuit 4 outputs an offset signal to a reference speed generating circuit 1. The offset signal controls displacement of a target speed curve of the target speed outputted from the reference speed generating circuit 1 so that the length to the target position is smaller than a prescribed value apparently. When the control rushes into a deceleration control section, a signal is outputted from a deceleration section detecting circuit 3 to the offset generating circuit 4, and the output of the offset signal is released, and the current flowed to a VCM7 is controlled by the speed error obtained from controlled target speed and actual speed to position accurately and quickly a recording/reproducing head (omitted in a figure) to the target position.

A GTD study of pyramidal horns for offset reflector antenna applications

Abstract: An efficient computational method is demonstrated for determining the far-field patterns of reflectors illuminated by pyramidal horns. A uniform geometrical theory of diffraction (GTD) formulation is used to determine the near- and far-fields of the horn. The far-field patterns of the offset reflector are constructed using the physical optics (PO) formulation in conjunction with the Jacobi-Bessel expansion method. Many representative results are shown for the far-field patterns of the reflector. In particular, the concept of the optimum phase center for the best location of a horn illuminating a reflector is carefully studied and some useful observations are made.

Inductive sensor arrangement and measuring arrangement for its use

Abstract: The invention includes a measuring arrangement and an inductive sensor arrangement with a transmitter coil which is fed by an RF oscillator, and a receiver coil in which an alternating field is induced by the transmitter coil. Transmitter coil and/or receiver coil are subdivided into at least two part-windings which are connected in opposition to one another in such a manner that the induced part-voltages at least partially cancel. The part-windings are arranged with respect to a metallic object in such a manner that when the position changes in at least one direction, the relative position of each individual part-winding with respect to the object changes differently. This results in a different influence on the inductances of the two part-windings with corresponding change in phase angle and output voltage. The relative distance of each part-winding from the object is monitored by means of auxiliary sensors. If the respective distances deviate, the auxiliary sensors produce a compensation signal by means of which errors due to an inclined position of the object or offset object edges can be avoided.

Warning device for ghost drivers

Abstract: The subject of the invention is a warning device at motorway intersections to prevent traffic from joining the motorway in the wrong direction. For this purpose, an optical illusion of a warning bollard or barrier is produced, which is made up of individual light-emitting or light-reflecting elements which are offset stepwise. These elements can optionally be arranged in the shape of a ramp or a stepped pattern or offset obliquely in one plane one behind the other.

Controlling and correcting device of focus

Abstract: PURPOSE:To maintain a condensed beam always in the most stopped down state on a disc surface, by applying an offset automatically to a focus controlling system so as to maximize a tracking error signal at all times. CONSTITUTION:A control circuit 1 outputs a track moving signal 1a and a switch changeover signal 1b in the starting stage of a device and in the waiting time for instruction, so that a beam spot 10 is oscillated in a tracking direction. Further said circuit outputs a focus offset signal 1c to an error amplifier 7 to apply an offset to a focus controlling system. The amplitude level of the error signal when the beam spot is oscillated while the rate of the focus offset is increased at a specified rate at every half period of the track moving signal is detected, by which the max. value thereof can be detected. Thus, the focus offset rate at which the beam spot 10 is most stopped down on the surface of a disc 9 is obtained.

A drum motor

Abstract: not available for EP0091442Abstract of corresponding document: WO8300954In a drum motor having a driving electric motor and a gear transmission (16, 17, 18) between the motor armature (14) and an internal toothing (22) in an end cover (2) connected to the shell (1), the gear transmission (16, 17, 18) is offset with respect to the shaft (6) on which the end cover (2) is journalled, and this shaft (6) has an axial bore (8) through which the necessary wires (9) for supplying power to the electric motor are introduced. This enables stocking of a plurality of drum motors of different lengths and motor outputs merely by changing the length of the shell (1) and the length of the shaft (7) opposite the gear transmission (16, 17, 18), it being unnecessary to change the structure around the wire lead-in mount. The wires (9) may be run from the internal mouth (24) of the bore (8) to the stator winding (25) of the motor through a pipe section (23).

Remote operation of optical system

Abstract: A method and apparatus for controlling a detector array based optical system using reflected or transmitted light for machine vision is disclosed. The light characteristic such as power (intensity) or distribution of power received by said optical system is detected and an electrical signal indicative of the characteristic is transmitted to a remote control system. The control system then adjusts a light power related variable of the optical system when the received light characteristic signal is deficient. A method and apparatus for linearizing the output of a diode array is also disclosed. An element correction array is set up in a microprocessor and an encoding device providing precise edge movement data is moved past the elements of the diode array so that the data from the encoder and from the diode array can be compared and the difference inputted as offset values for the corresponding positions of the elements in the correction array. Thereafter, during operation, the offset values are added to the diode array element reading to obtain a corrected diode array output which is substantially linear.

Digital signal processing device

Abstract: PURPOSE:To attain the increase in accuracy of an A/D converter by offsetting a prescribed signal to an analog input section of an A/D converter to average a digital signal after A/D conversion. CONSTITUTION:An offset signal of m/n-level (0<=m

Offset spherical dual-reflector antenna

Abstract: The dual offset spherical reflector antenna offers the advantage of a circularly symmetric main reflector together with a subreflector possessing an axis of symmetry. These features could lead to significant cost reductions in manufacture compared to existing offset designs. Initial results of a parametric study, using physical optics, show that 64% efficiency is possible with a peak crosspolar level below ?35 dB, together with very low sidelobes.

Look-back analog to digital converter

Abstract: In an analog-to-digital converter implemented in logic operating on the multiple lobes of a threshold curve, such as Josephson SQUIDs, two sampling registers are provided with sufficient offset to guarantee stability at sampling in one or the other regardless of other factors. Knowledge of bit value of the next lower bit order position permits determination of which sampling is valid. Encoder logic selects the valid sampling register retroactively. Each sampling register bit order position has two sampling SQUIDs and latching self-gated ANDs. Bias values are provided at higher orders to increment the phase offset so as to ensure low-to-high order readout. The lowest two bit orders may be implemented in simplified logic, effectively giving two bit order positions for logic and SQUIDs equal to that of one higher order bit position.