Predetermined Threshold Value Research Articles

Single Threshold Selection Strategy In The Group Interview Problem

In many decision situations such as selling an asset on the open market, a decision maker receives a random sequence of offers. Following an evaluation of each offer, the decision maker must decide whether to take the current offer or reject it and consider the next one. One of the simple selection strategies in the sequential decision problem is via an aspiration-level or a threshold value, which allows the decision maker to select the first offer that is higher than the pre-determined threshold value. For the so-called group interview problem in which a number of offers or choices are presented sequentially in groups, we derive the optimal threshold value (1) to maximize the probability of selecting the best choice and (2) to maximize the expected value of the selected choice. For the cases where the order of groups can be rearranged for evaluation, an exact solution is derived for the optimal sequencing of groups. There are many potential applications of the selection strategy, including product pricing strategy and consumer search and purchase process.

Performance analysis of reactive congestion control based upon queue length threshold values

Reactive congestion control based upon two thresholds is analyzed. Under the congestion control treated here, a multiplexer or transit node in the network recognizes congestion when its queue length reaches some pre-determined threshold value, denoted by H. The congested node then explicitly informs the sources sharing the node of its congestion in some way to mark a forward congestion notification bit in the header of cells if provided, or to directly send control cells to those sources. The sources then stop the cell transmission according to the feedback information received. The relief of congestion is recognized by the node when its queue length decreases to some low-threshold, L, and informs the sources that the sources can again start the cell transmission. In this paper, we investigate this sort of congestion control by forming a queueing network, in which multiple sources and a single node are explicitly modeled. Through an analysis, we discuss the impact of those two thresholds on performance of the congestion control.

Arrangement for enhancing the processing of speech signals in digital speech interpolation equipment

A facility is provided in a telecommunications network which causes Digital Speech Interpolation (DSI) apparatus to transmit noise signals toward a destination if the level of the noise signals at least equals a predetermined threshold value, in which the predetermined threshold value is selected, in accord with an aspect of the invention, as a function of a type of telephone service subscribed to by the telephone station set involved in the associated telephone call.

Experimental results on an hybrid superconducting current limiter

The superconducting current limiter, a device without classical equivalent, appears to be one of the most promising and innovative applied superconducting devices for electric power systems. Its operation is based on the ultra-fast and natural transition of a superconducting coil when the current oversteps a predetermined threshold value. The authors propose a hybrid device consisting of a resistive series transformer and superconducting coils. The superconducting coils trigger the limitation. The latter is ensured by the primary self inductance of the transformer. This design allows the reduction of the current through the superconducting cable, the volume of superconductor and the cryogenic losses under normal operation. These advantages are brought about by a transformer whose magnetic coupling between the windings changes accordingly to the mode of operation. To study this device experimentally, a 150 V-50 A model has been developed. This model has been exposed to a number of tests under normal and fault operations. The results have demonstrated the satisfactory performance of this hybrid device, at least at a reduced scale. With a view to an industrial device, a 63 kV-1250 A system has been theoretically designed.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Apparatus for enhancing monophonic audio signals using phase shifters

A method and apparatus for generating control voltage signals in a surround sound processor is disclosed which utilizes a one-shot monostable multivibrator for minimizing intermodulation distortion while following rapid directional changes, yet minimizing intermodulation distortion. The apparatus includes means for smoothing the directional information signals derived from audio input signals each with a continuously variable time constant to generate a corresponding control voltage signal, such that each time constant depends inversely upon the magnitude of the difference between the directional information signal applied thereto and the corresponding control voltage signal generated thereby. A one-shot means temporarily reduces the value of the continuously variable time constant associated with each of the smoothing means to a predetermined minimum value for a short, predetermined time period so that each of the corresponding control voltage signals rapidly approaches the value of its corresponding directional information signal within this time period, the one-shot being activated when the difference between any one of the directional information signals and its corresponding control voltage signal exceeds a predetermined threshold value. Other improvements are incorporated in the surround sound processor to optimize its performance.

Speaker verifier using nearest-neighbor distance measure

A speaker verification system which accepts or rejects the claimed identity of an individual based on analysis and measurements of the speaker's utterances. The utterances are elicited by prompting the individual seeking identification to read test phrases chosen at random by the verification system composed of words from a small vocabulary. Nearest-neighbor distances between speech frames derived from such spoken test phrases and speech frames of corresponding vocabulary "words" from previously stored utterances of the speaker seeking identification are computed along with distances between such spoken test phrases and corresponding vocabulary words for a set of reference speakers. The claim for identification is accepted or rejected based on the relationship among such distances and a predetermined threshold value.

Arrangement for detecting an object by means of sound conducted through a solid body and method of using such arrangement

A method and apparatus for detecting an impact sound, such as a sound caused by a railroad vehicle approaching a construction location. The apparatus comprises an arrangement for detecting impact sound or vibrations with a receiver mounted at the rail, for example, and, further, an evaluation circuit for processing the vibrations and triggering a warning signal when the intensity of the receiver-output signal continuously increases, for example, when the intensity in a predetermined frequency range passes through predetermined threshold values during predetermined times. Thus, an approaching railroad vehicle can be positively detected by monitoring a continuously increasing sound or vibration which is propagated in the rails.

Speech coding circuit

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Ultrasonic Doppler blood flow measuring apparatus

An ultrasonic Doppler blood flow measuring apparatus comprises a plurality of frame memories for storing information pieces about a blood flow speed in a unit of frame, circuits for comparing blood flow speed information pieces at corresponding addresses on the plurality of frame, memories and determining a speed difference, a circuit for comparing the speed difference with a predetermined threshold value and determining a blood flow at the corresponding address as an arterial flow when the speed difference exceeds the threshold value but as a venous flow when the speed difference is below the threshold value, and a circuit for displaying the determined arterial and venous flows in different colors.

Time constant processing circuit for surround processor

A method and apparatus for generating control voltage signals in a surround sound processor is disclosed which utilizes a one-shot monostable multivibrator for minimizing intermodulation distortion while following rapid directional changes, yet minimizing intermodulation distortion. The apparatus includes a circuit for smoothing the directional information signals derived from audio input signals each with a continuously variable time constant to generate a corresponding control voltage signal, such that each time constant depends inversely upon the magnitude of the difference between the directional information signal applied thereto and the corresponding control voltage signal generated thereby. A one-shot circuit temporarily reduces the value of the continuously variable time constant associated with each smoothing circuit to a predetermined minimum value for a short, predetermined time period so that each of the corresponding control voltage signals rapidly approaches the value of its corresponding directional information signal within this time period, the one-shot being activated when the difference between any one of the directional information signals and its corresponding control voltage signal exceeds a predetermined threshold value. Other improvements are incorporated in the surround sound processor to optimize its performance.

Prediction of the equilibrium value of a potentiometric signal. Application of the measuring tecnique to molecule-sensitive sensors

A measuring technique suitable for the prediction of the electroanalytical equilibrium signal of a potentiometric sensor is described, based on the evaluation of asymptotes of the response of the cell and the confidence interval from the signals measured in the so-called information dominant section of the response. The equilibrium voltage can be evaluated with the great precision by comparing the calculated data with a predetermined threshold value. The technique was applied to the determination of the equilibrium signal of a carbon dioxide sensor.

Musical tone control apparatus

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Automated Irrigation Based on Threshold Canopy Temperature

An automated drip irrigation system was controlled by continuously measuring cotton canopy temperature and computing 15-minute averages in a three-year field study between 1988-1990. Irrigation was applied only when average canopy temperature exceeded predetermined threshold values. Threshold temperatures were tested in 2 C increments between 26 C and 32 C. The length of irrigation cycles was shortest and amount per irrigation event was highest for all threshold temperatures during the early growth stage because canopies were small and warm bare soil contributed to measured canopy temperature. The ratio of water use to reference evapotranspiration decreased as threshold canopy temperature increased from 26 C to 32 C, but water use efficiency increased. Average canopy temperature during the period DOY 198 to 273, while net radiation exceeded 300 W m-2 and air temperature at 2 m exceeded 28 C, increased as threshold canopy temperature increased. Lint yield was highest for the 28 C threshold temperature and decreased for higher or lower threshold temperatures. Threshold temperatures = 28 C restricted water application and created increasing levels of water stress. The 28 C threshold should provide maximum lint yield where water supply and season length do not limit production. Under limited production conditions a 30 C threshold may be preferable to a 28 C threshold because lint yield is only slightly reduced but water use efficiency is higher and cotton matures more rapidly. Maximum yields were produced by 28 C and 30 C threshold canopy temperatures in which total seasonal water use ranged between 64 and 84 cm.

Automated Irrigation Based on Threshold Canopy Temperature

An automated drip irrigation system was controlled by continuously measuring cotton canopy temperature and computing 15-minute averages in a three-year field study between 1988-1990. Irrigation was applied only when average canopy temperature exceeded predetermined threshold values. Threshold temperatures were tested in 2 C increments between 26 C and 32 C. The length of irrigation cycles was shortest and amount per irrigation event was highest for all threshold temperatures during the early growth stage because canopies were small and warm bare soil contributed to measured canopy temperature. The ratio of water use to reference evapotranspiration decreased as threshold canopy temperature increased from 26 C to 32 C, but water use efficiency increased. Average canopy temperature during the period DOY 198 to 273, while net radiation exceeded 300 W m-2 and air temperature at 2 m exceeded 28 C, increased as threshold canopy temperature increased. Lint yield was highest for the 28 C threshold temperature and decreased for higher or lower threshold temperatures. Threshold temperatures = 28 C restricted water application and created increasing levels of water stress. The 28 C threshold should provide maximum lint yield where water supply and season length do not limit production. Under limited production conditions a 30 C threshold may be preferable to a 28 C threshold because lint yield is only slightly reduced but water use efficiency is higher and cotton matures more rapidly. Maximum yields were produced by 28 C and 30 C threshold canopy temperatures in which total seasonal water use ranged between 64 and 84 cm.

Voiceband signal classification

A signal is classified as one among a plurality of classifications by employing the autocorrelation of a complex low-pass version of the signal, i.e., the complex autocorrelation. The normalized magnitude of the complex autocorrelation obtained at a prescribed delay interval, i.e., "lag", is compared to predetermined threshold values to classify the signal as having one of a plurality of baud rates.

An efficient method for determining economical configurations of elementary packet-switched networks

The packet-switched network design problem can be formulated as a capacity and flow assignment (CFA) problem. The CFA problem is investigated for an elementary network consisting of one tandem switch and n local switches. It is regarded as the structural unit of a hierarchical network. It is assumed that any line speed is available and the cost of each line is a linear function of its speed with a fixed charge for installation. This CFA problem is shown to be equivalent to a 0-1 integer programming problem with a discontinuous cost function. A threshold rule and a row-wise or column-wise improvement (RCI) iteration are proposed to solve the problem. The threshold rule assigns all the traffic between two local switches to a direct route if the required traffic exceeds a predetermined threshold value, and otherwise to a tandem route. The RCI iteration searches the vertices of the unit cube of 2n-dimensional Euclidean space by a procedure roughly like the simplex method. Whenever the network has external traffic, direct application of the threshold rule ensures a global optimum. When there is no external traffic, a simple modification of the RCI iteration yields almost a global optimum within 2n steps. >

4729098 System and method employing nonlinear interpolation for the display of surface structures contained within the interior region of a solid body

A method and apparatus for displaying three dimensional surface images includes the utilization of a case table for rapid retrieval of surface approximation information. Eight cubically adjacent data points associated with a given voxel element are compared with a predetermined threshold value or range to generate an eight bit vector. This eight bit vector is employed to rapidly produce vector lists of approximating surfaces. A non-linear interpolation operation is performed so as to more closely approximate the desired surface and to provide more accurate representations of vectors normal to the desired surface. The accurate representation of these normal directions provides means for accurately representing shading information on a display screen. The method and apparatus of the present invention are particularly useful for the display of medical images both from X-ray generated data and from data generated from various other sources including magnetic resonance imaging and positron emission tomography. The present invention provides a means for rapid generation of three dimensional images so as to enable interactive use by medical practitioners.

4710876 System and method for the display of surface structures contained within the interior region of a solid body

A method and apparatus for displaying three dimensional surface images includes the utilization of a case table for rapid retrieval of surface approximation information. Eight cubically adjacent data points associated with a given voxel element are compared with a predetermined threshold value or range to generate an eight bit vector. This eight bit vector is employed to rapidly produce vector lists of approximating surfaces. An interpolation operation is performed so as to more closely approximate the desired surface and to provide more accurate representations of vectors normal to the desired surface. The accurate representation of these normal directions provides means for accurately representing shading information on a display screen. The method and apparatus of the present invention are particularly useful for the display of medical images both, from x-ray generated data and from data generated from various other sources including magnetic resonance imaging and positron emission tomography. The present invention provides a means for rapid generation of three dimensional images so as to enable interactive use by medical practitioners.

Apparatus for reducing vehicle drive train vibrations

An apparatus for reducing the transmission of vibrations from an engine to a transmission line having a divided flywheel with first and second flywheel elements is provided by the in which the two flywheels are connected to the engine and transmission line, and are respectively connected by a spring mounting and at least two frictional clutches positioned between the two flywheels. The second frictional clutch has frictional contact smaller than the maximum torque of the engine and relative movements between the flywheel elements are effectively damped when the forces acting between the flywheel elements in these relative movements are weaker than the maximum engine torque, but stronger than a predetermined threshold value.

Microprocessor-based overfluxing relay for a generator transformer

This paper describes a microprocessor-based overfluxing relay meant to protect a generator transformer under over-excitation conditions. The relay continuously monitors the system voltage and frequency and takes alarm and trip decisions on the basis of transformer iron losses computed by the microprocessor. An alarm signal is given when the total iron loss exceeds a predetermined threshold value continually for half a second and a trip signal is issued if the condition continues for 5–99 s (adjustable). The operating value of iron loss is adjustable over the range of 1·1 to 1·5 times the iron loss at rated voltage and rated frequency. A relay prototype based on an 8-bit microprocessor 8085A has been tested successfully in the laboratory.