Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 84 for “"Slew"”.
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High Slew Rate High-efficiency Dc-dc Converter
… to improve VR transient response at high slew rate load, which engages in transient periods operating in MHZ to inject high slew rate current in step up load and recovers energy in step down load. Main VR operates in low switching frequency mainly providing DC current. Parallel ATVC has …
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Modeling and Slew-Maneuver Control of a Flexible Spacecraft
<p>Slew-maneuver control problem is studied for a flexible spacecraft consisting of a rigid main body to which a long flexible appendage is attached. Nonlinear dynamical system models are developed using both distributed parameter modeling and discrete parameter modeling; these models are shown to …
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Design and analysis of a 200 volt, high slew rate, current-limited operational amplifier
… steps anywhere in a 200 V range, with ideal slew rates measuring in the kV/s range, while having clean, adjustable current limiting and low quiescent current consumption. Several common amplifier topologies are examined, with their merits and drawbacks discussed in the context of the use …
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Design of Multidimensional Large -Tip -Angle Radiofrequency Pulses for Parallel Transmission in Magnetic Resonance Imaging
… of spiral trajectories, termed the variable slew-rate spirals, is proposed to locally reduce B 1 amplitude of 2D RF pulses. The peak B1 reduction is achieved by changing the gradient slew-rate profile, and hardware constraints such as gradient amplitude and slew-rate constraints are …
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Approaches to optimal inertial instrument calibration using slewing
… system and (2) an inertially referenced slew. An inertially referenced slew rotates the inertial measurement unit with respect to an inertial reference frame independent of the vehicle motion. The appropriate inertially referenced slew is determined by a proposed optimal calibration …
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Computationally efficient characterization of standard cells for statistical static timing analysis
… characterize the propagation delay and output slew of an individual cell for subsequent timing path analyses. Its efficiency stems from the fact that it only needs to find the delay or output slew in the vicinity of the ?- sigma operating point (where ? = 0 to 3) rather than the entire …
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Clock tree synthesis under aggressive buffer insertion
… has more freedom and thus achieves more robust slew control. Buffer insertion along routing paths had been mostly avoided previously due to the difficulty of maintaining a low skew under such aggressive buffer insertion. We developed an accurate timing analysis engine for delay and slew …
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Optimal Slewing of a Constrained Telescope Using Seventh Order Polynomial Input Torques
… of motion. This paper presents a method for slewing a telescope in space with a gimbaled sensor attached to a nominally non-rotating spacecraft using two seventh order polynomial input functions to characterize torques. To accomplish this task, picking the optimal coefficients of the seventh …
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A space for conflict : the scab acts of the Cape Colony, circa 1874-1911
… presented their opinions of the disease in a slew of letters to the press and in testimonies before various scab commissions. Although the farmers' beliefs about scab were heterogeneous, they contained elements of an environmental theory of disease.
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Novel approaches in current-feedback operational amplifier design
… of improving CMRR, bandwidth, Voltage-Offset and Slew-rate performance. The majority of the results of this work have been reported by the author in references [11 to [6]. Initially a thorough analysis of the conventional CFOA was undertaken to provide an in depth understanding of the amplifier's …
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High Performance Digital Control Techniques for Powering Microprocessors
… delay and maximizes the inductor current slew rate; and the transient detection circuit recognizes the load transient state in a manner adaptive to the amount and slew rate of load transient. Theoretical, simulation and experimental results prove the effective operation and excellent …
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A high voltage, high current, low error operational amplifier with novel features
… which extends the large signal bandwidth and slew rate of the amplifier. Amplifier performance is evaluated through simulation in Cadence and ADICE (SPICE). The amplifier is capable of driving 1 Ampere through capacitive and resistive loads. The result is a low distortion amplifier with …
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Variable Precision Tandem Analog-to-Digital Converter (ADC)
… varies its precision as a function of input slew rate (maximum signal rate of change), in order to best follow the input in real time. It uses Flash and Successive Approximation (SAR) conversion techniques in sequence.</p> <p>As part of the design, the concept of "total real-time …
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The spectroscopy of bound and predissociating Rydberg states of NO in external electric fields
… dynamics. In Chapter 6, ramped fields of varying slew rates are applied to the bound Rydberg states of NO, and the ionisation time profiles are obtained. The development of the experimental chamber and investigation into sources of electrical noise required to achieve this is discussed. It is …
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Design and integration of a three degrees-of freedom robotic vehicle with control moment gyro for the Autonomous Multiagent Physically Interacting Spacecraft (AMPHIS) testbed
… Furthermore, it provides the vehicle with high slew-rate capability, a key measure of performance in on orbit spacecraft assembly. Simulation and experimental results are presented for the prototype AMPHIS vehicle, demonstrating a potential slew-rate of 4.8 deg/s for a 30 degree rest-to-rest …
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The Modeling of Partial Discharge under Fast, Repetitive Voltage Pulses Using Finite-Element Analysis
… the merits of wide bandgap devices is that their slew rates and switching frequencies are much higher than silicon-based devices. However, from the insulation side, frequency and slew rate are two of the most critical factors of a voltage pulse, influencing the level of degradation of the …
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Output feedback rotational maneuvers and vibration damping of Nasa Scole system by inversion theory
… includes the dynamical equations for rigid body slew maneuver and three dimensional vibration of the rigid space shuttle, the flexible beam and the reflector with an offset mass. The contribution of this thesis lies in the development of two control systems based on (i) Euler angles or (ii) …
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Optimizing Parameters and Controls for Maneuvering Flexible Structures
… Numerical examples are presented for single axis slew maneuvers of a symmetric four boom flexible structure.
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The Fréchet distance revisited and extended
… Using this new algorithm we can solve a slew of new problems, from computing a median curve for a given collection of curves, to various motion planning problems. Additionally, we show that for the median curve problem, when the k input curves are c-packed, one can (1+epsilon)-approximate …
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Spacecraft nonlinear attitude control with bounded control input
… for the case of spacecraft large angle slew manoeuvres. The idea of undergoing such manoeuvres using control moment gyros to track commanded angular momentum rather than a torque command has also been studied. In this context, a gimbal position command generation algorithm has been …
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