Design and analysis of a microprocessor-controlledpeak-power-tracking system [for solar cell arrays]

Stability and dynamics of a series configuration peak-power tracking (PPT) system are analyzed. The operating modes of the system, as well as mode transitions, are investigated based on qualitative graphical representations of dc load lines at various interfaces of the system. Analysis of multiloop control in the PPT mode is discussed. This includes the design of the inner voltage loop and analysis of the closed-loop system stability around the peak-power point. For an optimum dynamic performance and stability, design parameters of the inner voltage loop and the outer PPT loop are identified. Experimental verifications, supported by simulation results, are performed     

Automatic Checkout and Monitoring in the AN TPQ-27 Radar System

This paper describes automatic monitoring equipment built in to a precision tracking radar system to detect and isolate faults. The purpose of the monitoring equipment is to minimize the mean time to repair faults and to exercise the overall system for pre-mission alignment and calibration. In addition, it is used to periodically check for performance degradation in key areas of the system. The paper describes the design approach used to meet the above requirements. Three types of signals are monitored: analog, digital, and switch closure. A list of each type is given and the technique used to monitor each is described. The design approach for pre-mission alignment and calibration is outlined. Tests performed are: RF alignment of the boresight axis, range tracking accuracy, angle servo calibration and accuracy, and receiver figure of merit measurements.     

GENERATION AND APPLICATION OF UNSTRUCTURED ADAPTIVE MESHES WITH MOVING BOUNDARIES

INTRODUCTIONMany engineering applications require thenumerical prediction of strongly unsteady flowsinteracting with moving bodies.A case in pointis that the detailed calculation of sphere motionsin an unsteady field induced by blast waves is akey issue to determine the drag force exerting up-on the sphere by the surrounding gas and,inturn,to reveal the mechanism of unsteady effectson the drag coefficient.To cope with such pro-blems,one should simulate unsteady flows withmoving boundary co…     

Performance comparisons of modified SMI and GLR algorithms

Adaptive filtering for signal detection in colored interference of unknown statistics is addressed. The detection performance of a modified version of the well-known sample matrix inversion (SMI) algorithm, called the modified SMI (MSMI), is compared with that of the generalized likelihood ratio (GLR) algorithm in colored Gaussian interference. The performance sensitivity of the MSMI and GLR in colored Weibull and log-normal interference is studied via simulation. It is found that there is almost no need to use the more complicated GLR algorithm in Gaussian interference, while in Weibull or log-normal interference the GLR should be preferable to the MSMI     

巴尔迪克-径向铆接--满足最精确的铆接成形要求

巴尔迪克的铆接法可铆接以前被认为不可铆接的材料,并能得到完美的铆接面。材料沿径向滚动可防止产生扭应力,从而得到高质量的铆接面并具有很高的抗疲劳强度     

Derating Concerns for Microprocessors Used in Safety-Critical Applications

The use of commercial-off-the-shelf (COTS) microprocessors for safety-critical applications usually implies derating of the device to make it work in harsh environments. We discuss derating concerns for state-of-the-art microprocessors. Issues addressed herein include noise margins due to low voltage levels, multiple power supplies, frequency and current derating concerns, error sources, timing degradation, power-aware architectures, and new advanced microprocessor derating features.     

The Collision of Comet Shoemaker-Levy 9 with Jupiter

The discovery of Comet Shoemaker-Levy 9 in March 1993 opened an extraordinary few years in the study of the history of impacts in the solar system. This review paper offers a background that attempts to set the events of 1993 and 1994 into a historical context, and describes events leading to the discovery and the mounting of a unique and unprecedented international effort to observe the comet's collision with Jupiter. A selection of the results is presented to explore how the fate of Comet Shoemaker-Levy 9 has affected scientific and popular understanding of impacts in the solar system.     

Detectability Loss Due to "Greatest Of" Selection in a Cell-Averaging CFAR

Curves are presented showing the additional constant false-alarm rate (CFAR) loss which results when a "greatest of" logic is imple mented between the leading and lagging sets of reference cells. Thee analytical results for a square law detector and a Swerling case 1 fluctuating target are supplemented by simulation results for a nonfluctuating target, and envelope and logarithmic detector laws.