This paper discusses techniques for transmitting smoothed video more efficiently over a wireless network. The fluctuation of wireless channel conditions can add a significant amount of delay to video packets and cause...
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This paper discusses techniques for transmitting smoothed video more efficiently over a wireless network. The fluctuation of wireless channel conditions can add a significant amount of delay to video packets and cause them to miss their play-out time. If a video is smoothed, it is possible to selectively deliver packets delayed at the base-station to reduce the impact of the missing packets on video quality. In this paper, we present a simple yet effective packet selection algorithm which accomplishes this goal. This algorithm determines whether to transmit a packet based on channel conditions as well as the likelihood that higher priority layers in the rest of the video will be delivered on time. We introduce the concept of quality index to measure the performance of the algorithm. Results from trace-driven simulations show that the performance of the algorithm is close to optimal under a wide variety of channel conditions when the threshold is set between 0.7 and 0.9. (C) 2000 Academic Press.
'Minimum' sets of complementary areas represent all species in a region a given number of times. In recent years, conservation assessments have centred around the the evaluation of these 'minimum' sets...
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'Minimum' sets of complementary areas represent all species in a region a given number of times. In recent years, conservation assessments have centred around the the evaluation of these 'minimum' sets. Previous research shows little overlap between minimum' sets and existing nature reserves and between 'minimum' sets Cur different taxonomic groups. The latter has been used as an argument to discount the use of indicator taxa in the selection of sites for nature reserves. However, these 'minimum' set analyses have only considered a single set for each taxonomic group when there are, in fact. a large number of equally valid 'minimum' sets. We present new methods for evaluating all of these alternative 'minimum' sets. Wt demonstrate that if all of the sets are evaluated, significantly higher levels of overlap are found between 'minimum' sets and nature reserves, and pairs of 'minimum' sets for different taxonomic groups. Furthermore, significantly higher proportions of species from non-target taxonomic groups are recorded in the 'minimum' sets of target Stoups Our results suggest that previous conservation assessments using 'minimum' sets may have been unduly pessimistic.
A simple and efficient method for optimal selection of weights, along with higher order performance indices for voltage contingency selection, has been suggested in this ***. Some of the existing performance indices f...
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A simple and efficient method for optimal selection of weights, along with higher order performance indices for voltage contingency selection, has been suggested in this ***. Some of the existing performance indices for voltage contingency selection has been critically reviewed. The proposed performance indices are able to eliminate misranking and masking effects. The post-outage quantities have been computed, using a new set of distribution factors, defned in terms of pre-outage real and reactive power flows in transmission lines/ outputs of generators. The proposed algorithm has been tested on IEEE 14-bus system and a practical 75-bus Indian system.
Corpus based approaches to unit selection for concatenative speech synthesis have become popular in recent years due to their improved sensitivity to unit context over their more simple predecessors. These systems usu...
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ISBN:
(纸本)0780362934
Corpus based approaches to unit selection for concatenative speech synthesis have become popular in recent years due to their improved sensitivity to unit context over their more simple predecessors. These systems usually make use of large speech databases and employ sophisticated search algorithms to determine the optimal unit sequence to use to synthesise each sentence. For many applications it is not possible to have the entire database, which may be as large as several hundred megabytes. available to the synthesiser at runtime. What is required is some form of off-line pre-selection algorithm to determine which subset of the database enables the highest quality speech synthesis to be performed for a given runtime system size. This paper describes a pre-selection algorithm developed at IBM for use with decision-tree-based concatenative speech synthesisers.
A scheme for sequencing of tasks on a microspacecraft platform is outlined. The scheme is easily implemented by virtue of its computational simplicity. The strategy is derived from optimal control theory. Action selec...
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A scheme for sequencing of tasks on a microspacecraft platform is outlined. The scheme is easily implemented by virtue of its computational simplicity. The strategy is derived from optimal control theory. Action selection with the cue-deficit algorithm is found to perform well on the present microsatellite simulation and to be demonstrably robust to significant failures of the satellite solar array. Robustness to failures of payload, transmitters, and injection into nonoptimum orbits, such as elliptical transfer orbits, rather than the mission orbit, is also demonstrated. (AIAA)
In our previous work, we developed a new actuator placement algorithm that is capable of selecting the best actuator placement for active noise control problems over a broad band of frequencies. The actuator selection...
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In our previous work, we developed a new actuator placement algorithm that is capable of selecting the best actuator placement for active noise control problems over a broad band of frequencies. The actuator selection algorithm is based on a novel extension of the Householder QR subset selection algorithm. The QR algorithm uses the l(2) matrix norm as a performance measure. In this paper, numerical results generated by that algorithm are compared with numerical results generated using five different performance measures. These measures, which are based on different matrix norms and functions of the actuator frequency responses, yield actuator placements that result in active noise control systems with improved performance and robustness.
The design of the C-17 angle-of-attack limiter system is presented. The C-17, because of its T-tail, has a locked-in deep stall potential in some aft center of gravity configurations. The angle of-attack system uses a...
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The design of the C-17 angle-of-attack limiter system is presented. The C-17, because of its T-tail, has a locked-in deep stall potential in some aft center of gravity configurations. The angle of-attack system uses alpha measurements from three pairs of vanes for precise angle-of-attack control and to prevent excursion into the deep stall region. The vanes, because of their locations, are sensitive to sideslip angle excursions in varying degrees, therefore, requiring sideslip angle information for proper failure monitoring. A method of synthesizing sideslip and angle of attack using the information from the vanes was developed. With the synthesized angle of attack and sideslip, it was possible to provide a minimum of fail-operational-fail-operational capability with tight failure tolerance, After over 2000 stall tests and assaults to alpha limit, the pilot community has gained the confidence that the system will protect the C-17 from entering the locked in deep stall region.
Randomized selection algorithms on k-dimensional mesh-connected computers with multiple broadcasting are proposed in this paper. We first show that a leader can be elected in O(log N) time on any k-dimensional mesh-co...
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Randomized selection algorithms on k-dimensional mesh-connected computers with multiple broadcasting are proposed in this paper. We first show that a leader can be elected in O(log N) time on any k-dimensional mesh-connected computers with multiple broadcasting of size N. We then shaw that we can find the p-ah smallest element among a data set of size N in O((log N+k+N-1/(k(k+1)) log N) expected time using a regular N-1/k x...x N-1/k k-dimensional mesh and in O((log N+k(2)N(1/(k2k))) log N) expected time rasing an irregular N-(2k-1k+1/(k2k))x N-(2k-2k+1/(k2k)) x...x N-(k+1/(k2k)) dimensional mesh, This leads to a selection algorithm, which runs In O((log N)(2)) expected time on a regular ((log N/log log N)(1/2)))-dimensional mesh ai on an irregular (log log N)-dimensional mesh each with N processors. To our best knowledge, this is the first polylogarithmic selection algorithm on meshes with multiple broadcasting.
We investigate the behaviour of P(R greater than or equal to r) and P(R less than or equal to-r) as r-->infinity for the random variable R:=Sigma(n=1)(infinity) Q(n) Pi(k=1)(n=1) M(k), where ((Q(k), M(k)))(k is an ...
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We investigate the behaviour of P(R greater than or equal to r) and P(R less than or equal to-r) as r-->infinity for the random variable R:=Sigma(n=1)(infinity) Q(n) Pi(k=1)(n=1) M(k), where ((Q(k), M(k)))(k is an element of N) is an independent, identically distributed sequence with P(-1 less than or equal to M less than or equal to 1)=1. Random variables of this type appear in insurance mathematics, as solutions of stochastic difference equations, in the analysis of probabilistic algorithms and elsewhere. Exponential and Poissonian tail behaviour can arise.
The problem of time-optimal reorientation of the inner gimbal of a two-degree-of-freedom gimballed gyroscope mounted on a nonrotating base is considered. The states in the gyro model are the gimbals' angles (nutat...
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The problem of time-optimal reorientation of the inner gimbal of a two-degree-of-freedom gimballed gyroscope mounted on a nonrotating base is considered. The states in the gyro model are the gimbals' angles (nutation is ignored). The model is nonlinear (not limited to small angles), state constrained, control limited, and double input, double output. A simple, explicit solution based on an intuitive observation is presented;it exploits the system's nonlinearity and channel coupling for attaining the minimum-time goal,It is analytically shown, in detail, that the solution satisfies the Maximum Principle and fulfills a sufficient condition for optimality based on the Hamilton-Jacobi-Bellman equation.
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