Revisit time

Keywords Radar sensor scheduling waveform beam-shape control detection tracking revisit time myopic non-myopic. 

The LMIPDA-IMM calculations are performed for all combinations of revisit times in A and waveforms in the library. Evidently then the number of combinations grows exponentially in the number of steps ahead, and soon becomes impractical for implementation. Having obtained the error covariance matrix for all possible combinations of sensor modes, the optimal sensor mode (waveform) is then chosen for each target to be the one which gives the longest re-visit time, while constraining the absolute value of the determinant of the error covariance matrix to be smaller than the prescribed upper limit K. In other words, our objective is... 

Scheduling is then done to permit a full scan over the prescribed scan period while also satisfying the constraints imposed by the revisit times obtained by the sensor scheduler. Once a target is measured, its revisit time is re-calculated. 

We have, on the other hand done simple simulations for the case of one-step ahead and two-step ahead scheduling. In the latter case, the revisit times and waveforms are calculated while the target states are propagated forward over two measurements, with the cost function being the absolute value of the determinant of the track error covariance after the second measurement. Only the first of these measurements is done before the revisit calculation is done again for that target, so that the second may never be implemented. 

Baker J. I. and Hites R. A. (2000b) Siskiwit Lake revisited time trends of polychlorinated dibenzo-/)-dioxin and diben-zofuran deposition at Isle Royale, Michigan. Environ. Set Technol 34, 2887-2891. 

Revisit Time. The revisit time required determines how well the radar can search the required search volume. Basically, the required power-aperture product can be determined from the targetRCS characteristics, search volume, and revisit time parameters. 

Typically, fast (> 1 update per second) and slow (< 1 update per second) track rates are available corresponding to precision and maintenance tracking functions. The automated radar control process generally gives higher priority to track than to search functions. Multiple search rasters may be used to facilitate satisfaction of user requirements. In air defense apphcations, a horizon fence raster could be deploy with a revisit time of a few seconds to detect cruise missiles while a larger volumetric search raster for aircraft detection could be repeated at intervals of tens of seconds. 

Recent X-Band sensors as the TerraSAR-X and the Cosmo-Skymed constellation are providing images with resolution never achieved in the past, in the meter/submeter regime with reduced revisiting times. As far as the latter aspect is concerned, the Cosmo-Skymed mission is worldwide the largest constellation for civilian... 

The influence of computers on the practice of organic chemistry is a significant recent development and will be revisited numerous times m the chapters that follow... 

Transient States which can arise oidy in the first tr < 2 time steps of an evolution. Since transient states do not lie on cycles, once a transient state is reached from a given initial state, it cannot be revisited later. 

But the periodic system is so fundamental, pervasive and familiar in the study of chemistry that it is often taken for granted. A century after the death of the leading discoverer of the periodic system, the Russian chemist Dimitri Mendeleev, it seems time to revisit the origins and modem status of this now-standard chemical classification. There were a number of historic precursors to Mendeleev s periodic system. But there are also current ongoing debates regarding the best way to display the periodic system, and whether there is really a "best way" of doing so. 

This is a problem that we have to revisit many times in later chapters. For now, draw the block diagram of the dye control system and provide the necessaiy transfer functions. Identify units in the diagram and any possible disturbances to the system. In addition, we do not know where to put the photodetector at this point. Let s just presume that the photodetector is placed 290 cm downstream. 

Example 7.4A. This time, let s revisit Example 7.4 (p. 7-8), which is a system with dead time. We would like to know how to start designing a PI controller. The closed-loop characteristic equation with a proportional controller is (again assuming the time unit is in min)... 

Task. Revisit the first case study and minimise wastewater for the 4 presented scenarios, where only duration for tasks is known, i.e. the start and ending times are variables rather than parameters. Consider time horizon to be fixed at 7.5 h. Does this improve or deteriorate the results Explain. 

Task Apply the algorithm presented in this chapter to the problem given in Table 5.2. This is indeed similar to the problem already presented in Chapter 4 and revisited in this chapter, except that only duration is given instead of prescribed starting and ending times. An added necessary condition that has to be considered is that operation C has to commence immediately after operation B and operation E has to commence immediately after operation D and not vice versa. Assume a time horizon of 12 h. 

Task Revisit the first example and perform the same analysis over 10 and 12 h time horizons. Note that the time points will have to be increased with the longer time horizon. Assess the computational intensity of the mathematical formulation as a function of the time horizon. 

Task Revisit the case study shown in Figs. 10.6 and 10.7 and apply the presented formulation over a 20 h time horizon. Assess the benefits of heat integration in this particular case, i.e. compare the energy requirements for the heat integrated case to the standalone case. 

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