323,307 research outputs found

    Design and Evaluation of Digital Baseband Converter Sub-channel Delay Compensation Method on Bandwidth Synthesis

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    The effect of sub-channel delay on bandwidth synthesis is investigated to eliminate the “phase step” phenomenon in bandwidth synthesis during the test of CDBE (Chinese Digital Backend). Through formula derivation, we realize that sub-channel delay may cause phase discontinuity between different sub-channels. Theoretical analysis shows that sub-channel delay can induce bandwidth synthesis error in group delay measurement of the linear system. Furthermore, in the differential delay measurement between two stations, bandwidth synthesis error may occur when the LO (Local Oscillator) frequency differences of corresponding sub-channels are not identical. Error-free conditions are discussed under different applications. The phase errors among different sub-channels can be removed manually. However, the most effective way is the compensation of sub-channel delay. A sub-channel delay calculation method based on Modelsim is proposed. The compensation method is detailed. Simulation and field experiments are presented to verify our approach

    Modelling,simulation, and analysis of HAL Bangalore13; international airport

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    Air traffic density in India and the world at large is growing fast and posing challenging13; problems. The problems encountered can be parameterized as flight delay, workload of air traffic13; controllers and noise levels in and around aerodromes. Prediction and quantification of these13; parameters aid in developing strategies for efficient air traffic management. In this study, the13; method used for quantifying is by simulation and analysis of the selected aerodrome and air13; space. This paper presents the results of simulation of HAL Bangalore International Airport,13; which is used by civil as well as military aircraft. With the test flying of unscheduled military13; aircraft and the increase in the civil air traffic, this airport is hitting the limit of acceptable delay.13; The workload on air traffic controllers is pushed to high during peak times. The noise contour13; prediction, especially for the test flying military aircraft is sounding a wake up call to the13; communities living in the vicinity of the Airport.13

    Narrowband delay tolerant protocols for WSN applications. Characterization and selection guide

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    This article focuses on delay tolerant protocols for Wireless Sensor Network (WSN) applications, considering both established and new protocols. We obtained a comparison of their characteristics by implementing all of them on an original platform for network simulation, and by testing their behavior on a common test-bench. Thereafter, matching the requirements linked to each application with the performances achieved in the test-bench, allowed us to define an application oriented protocol selection guide

    Dynamic Voltage Scaling Aware Delay Fault Testing

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    The application of Dynamic Voltage Scaling (DVS) to reduce energy consumption may have a detrimental impact on the quality of manufacturing tests employed to detect permanent faults. This paper analyses the influence of different voltage/frequency settings on fault detection within a DVS application. In particular, the effect of supply voltage on different types of delay faults is considered. This paper presents a study of these problems with simulation results. We have demonstrated that the test application time increases as we reduce the test voltage. We have also shown that for newer technologies we do not have to go to very low voltage levels for delay fault testing. We conclude that it is necessary to test at more than one operating voltage and that the lowest operating voltage does not necessarily give the best fault cover

    Simulator study of the effect of control-system time delays on the occurrence of pilot-induced oscillations and on pilot tracking performance with a space-shuttle-orbiter configuration

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    Using a six degree-of-freedom motion-base simulator, the effect of control-system time delays on the occurrence of pilot-induced oscillations (PIO's) on the vehicle handling qualities and on pilot tracking performance for a landing-approach configuration of the Space Shuttle orbiter was studied. A linearized math model was employed which represented a 300-knot orbiter with almost all time delays removed. Additional time delays were then inserted following the pilot's hand-controller signals. Only pitch and roll commands were used for vehicle control. The simulation employed an air to air tracking task as a means of emphasizing PIO tendencies. Two astronauts, two research pilots, and one simulation engineer served as test subjects. Results showed that PIO's occurred when the amount of added time delay approximated that existing for the orbiter configuration flown in the approach and landing tests. Increasing the amount of delay increased PIO occurrences and resulted in degraded tracking performance. Decreasing the amount of time delay eliminated the PIO's

    A Kolmogorov-Smirnov type test for shortfall dominance against parametric alternatives

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    This paper proposes a Kolmogorov-type test for the shortfall order (also known in the literature as the right-spread or excess-wealth order) against parametric alternatives. In the case of the null hypothesis corresponding to the Negative Exponential distribution, this provides a test for the new better than used in expectation (NBUE) property. Such a test is particularly useful in reliability applications as well as duration and income distribution analysis. The theoretical properties of the testing procedure are established. Simulation studies reveal that the test proposed in this paper performs well, even with moderate sample sizes. Applications to real data, namely chief executive officer (CEO) compensation data and flight delay data, illustrate the empirical relevance of the techniques described in this paper.Right-spread order; Excess-wealth order; New better than used in expectation; Bootstrap; Reliability; CEO compensation; Flight delay

    THE EFFECT OF SKEW ANGLE ON AVERAGE QUEUE DELAY AT TEE-INTERSECTIONS: A SIMULATION STUDY USING THE TEXAS MODEL

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    This thesis explores the effect of intersection skew angle on average queue delay through simulation. The simulation model used is the TEXAS (Traffic Experimental and Analytical Simulation) model. This microscopic simulation model uses a general nonlinear car-following model. It simulates individual intersections and was designed to capture the interaction of traffic operations and intersection geometry. Simulation models were developed for three stop-controlled, tee-intersections in Lincoln, Nebraska. Field data to develop and calibrate the simulation models were collected. All simulation models were calibrated by adjusting the car following parameters. An experimental design was developed to test the effect of skew angle on average queue delay. Skew angles from 1 degree to 30 degrees were evaluated. The average queue delay reported for each skew angle is based on 30 runs of the simulation model. The results indicate that skew angle does affect average queue delay. The results also suggest that the TEXAS model can capture the effect of skew on average queue delay for small skew angles of 1 degree from the base conditions. Advisor: Elizabeth G. Jone

    THE EFFECT OF SKEW ANGLE ON AVERAGE QUEUE DELAY AT TEE-INTERSECTIONS: A SIMULATION STUDY USING THE TEXAS MODEL

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    This thesis explores the effect of intersection skew angle on average queue delay through simulation. The simulation model used is the TEXAS (Traffic Experimental and Analytical Simulation) model. This microscopic simulation model uses a general nonlinear car-following model. It simulates individual intersections and was designed to capture the interaction of traffic operations and intersection geometry. Simulation models were developed for three stop-controlled, tee-intersections in Lincoln, Nebraska. Field data to develop and calibrate the simulation models were collected. All simulation models were calibrated by adjusting the car following parameters. An experimental design was developed to test the effect of skew angle on average queue delay. Skew angles from 1 degree to 30 degrees were evaluated. The average queue delay reported for each skew angle is based on 30 runs of the simulation model. The results indicate that skew angle does affect average queue delay. The results also suggest that the TEXAS model can capture the effect of skew on average queue delay for small skew angles of 1 degree from the base conditions. Advisor: Elizabeth G. Jone

    An Upper Bound to Zero-Delay Rate Distortion via Kalman Filtering for Vector Gaussian Sources

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    We deal with zero-delay source coding of a vector Gaussian autoregressive (AR) source subject to an average mean squared error (MSE) fidelity criterion. Toward this end, we consider the nonanticipative rate distortion function (NRDF) which is a lower bound to the causal and zero-delay rate distortion function (RDF). We use the realization scheme with feedback proposed in [1] to model the corresponding optimal "test-channel" of the NRDF, when considering vector Gaussian AR(1) sources subject to an average MSE distortion. We give conditions on the vector Gaussian AR(1) source to ensure asymptotic stationarity of the realization scheme (bounded performance). Then, we encode the vector innovations due to Kalman filtering via lattice quantization with subtractive dither and memoryless entropy coding. This coding scheme provides a tight upper bound to the zero-delay Gaussian RDF. We extend this result to vector Gaussian AR sources of any finite order. Further, we show that for infinite dimensional vector Gaussian AR sources of any finite order, the NRDF coincides with the zero-delay RDF. Our theoretical framework is corroborated with a simulation example.Comment: 7 pages, 6 figures, accepted for publication in IEEE Information Theory Workshop (ITW
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