A double stimulus subjective evaluation was performed to determine preferred frame rates at a fixed bit rate for low bit rate video. Stimuli consisted of eight reference color video sequences of size 352 × 240 pi...
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A double stimulus subjective evaluation was performed to determine preferred frame rates at a fixed bit rate for low bit rate video. Stimuli consisted of eight reference color video sequences of size 352 × 240 pixels. These were compressed at rates of 100, 200 and 300 kbps for low, medium, and high motion sequences, respectively, using three encoders and frame rates of 10. 15 and 30 frames per second. Twenty-two viewers ranked their frame rate preferences using an adjectival categorical scale. Their preferences were analyzed across sequence content, motion type, and encoder. Viewers preferred a frame rate of 15 frames per second across all categories, with several notable content-based exceptions.
A simple channel estimation sch.me for OFDM systems with transmitter diversity and a quasi-static fading channel is proposed. It is based on the assumption that the channel is highly correlated at nearby subcarriers. ...
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A simple channel estimation sch.me for OFDM systems with transmitter diversity and a quasi-static fading channel is proposed. It is based on the assumption that the channel is highly correlated at nearby subcarriers. For channel estimation, the pilot sequence is given a different circular time shift at each transmitter antenna, which is equivalent to phase modulation in the frequency domain. Then, nearby subcarriers are used to provide an orthogonal subspace to separate channel frequency responses between transmitter antennas and the receiver antenna. The channel estimator is a simple linear filter whose weight vectors can be precalculated. Using this sch.me, the system with transmitter diversity can be implemented with a minimal change in structure from the single antenna implementation. The transmitter diversity gain using the proposed channel estimation sch.me is demonstrated in the typical WLAN (Wireless LAN) environment. Significant improvement in error performance is achieved using a larger number of transmitter antennas when channel frequency coherence between nearby subcarriers is large.
We consider the problem of synchronization of all clocks in a sensor network, in the regime of asymptotically high node densities. We formulate this problem as one in which all clocks must line up with the clock of an...
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ISBN:
(纸本)1581137648
We consider the problem of synchronization of all clocks in a sensor network, in the regime of asymptotically high node densities. We formulate this problem as one in which all clocks must line up with the clock of an arbitrary node in the network (of course without assuming that this clock can be observed everywhere in the network, nor assuming that this node has any special hardware-this node could be any). We give a state-space description for the generation of observable data as a function of the ideal clock, and we derive an optimal estimator for determining the state of the ideal clock. A salient feature of our approach is that nodes collaborate to generate an aggregate waveform that can be observed simultaneously by all nodes, and that contains enough information to synchronize all clocks. This aggregate waveform effectively simulates the presence of a "super-node" capable of generating a high-power, network-wide time reference signal.
engineering students are often tinkerers. However, our students of today are more likely to have tinkered with software than hardware. This effect is readily seen in systems classes where students tend to visualize ea...
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engineering students are often tinkerers. However, our students of today are more likely to have tinkered with software than hardware. This effect is readily seen in systems classes where students tend to visualize each concept as a programming algorithm. This viewpoint must be balanced by exposure to implementation using hardware techniques. This can be accomplished at the sophomore level by carefully selec.ed examples in an introductory logic design course. Additional connections can be made in the first systems course. In this paper we outline an approach for connecting digital design to digital filtering. Concepts that could be beneficially exploited using this approach include latency, state, number representations, arithmetic hardware, and pipelining. Specific opportunities for making these connections in digital logic and systems classes are identified.
This study presents the effect of gate geometry on the charging characteristics of metal nanocrystal memories. The effect is studied by varying the perimeter to area ratio, number of convex corners and concave corners...
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This study presents the effect of gate geometry on the charging characteristics of metal nanocrystal memories. The effect is studied by varying the perimeter to area ratio, number of convex corners and concave corners of the gate of a metal-oxide-semiconductor (MOS) capacitor with embedded gold nanocrystals. It can be observed that the nanocrystal charging rate increases for a smaller perimeter to area ratio. The presence of concave and convex comers increases the nanocrystal charging rate. Based on this study it is expected that gate geometries with low perimeter to area ratio and with selec.ed convex and concave corners would increase the nanocrystal charging rate.
Implementations of adaptive filters using field programmable gate arrays require the ability to change the coefficient values of the filter based on the adaptation algorithm. Multiplierless filter designs rely on a pr...
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Implementations of adaptive filters using field programmable gate arrays require the ability to change the coefficient values of the filter based on the adaptation algorithm. Multiplierless filter designs rely on a priori knowledge of the coefficient values to implement the filter using hard-wired shifts and additions. We describe a multiplierless approach to adaptive filter implementation that reduces the complexity from quadratic to linear in the number of bits.
The methods used in integration and processing of optical functions into an elec.ronic system are discussed. Planar lightwave circuit interconnections at the board, module and chip level are being used for optical con...
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The methods used in integration and processing of optical functions into an elec.ronic system are discussed. Planar lightwave circuit interconnections at the board, module and chip level are being used for optical connections at very short distances. The integration of optical functions such as interconnection and sensing into system-on-package (SOP) and system-on-a-chip (SOC) application stands at a threshold similar to what elec.ronics faced in the year 1970. The method and costs of integration are critical to the implementation of optics in elec.ronic systems.
Many training, education, and visualization environments would benefit from realistic animated characters. Unfortunately, interfaces for character motion specification are often complex and ill-suited to non-experts. ...
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Many training, education, and visualization environments would benefit from realistic animated characters. Unfortunately, interfaces for character motion specification are often complex and ill-suited to non-experts. We present a tangible interface for basic character manipulation on planar surfaces. In particular, we focus on interface aspects specific to 2D gross character animation such as path and timing specification. Our approach allows for character manipulation and high-level motion specification through a natural metaphor - the figurine. We present an example interface for designing and visualizing strategy in the sport of American football and discuss usability studies of this interface.
This paper explores the problem of how to construct lazy decision tree ensembles. We present and empirically evaluate a relevance-based boosting-style algorithm that builds a lazy decision tree ensemble customized for...
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ISBN:
(纸本)1577351894
This paper explores the problem of how to construct lazy decision tree ensembles. We present and empirically evaluate a relevance-based boosting-style algorithm that builds a lazy decision tree ensemble customized for each test instance. From the experimental results, we conclude that our boosting-style algorithm significantly improves the performance of the base learner. An empirical comparison to boosted regular decision trees shows that ensembles of lazy decision trees achieve comparable accuracy and better comprehensibility. We also introduce a novel distance-based pruning strategy for the lazy decision tree algorithm to address the problem of over-fitting. Our experiments show that the pruning strategy improves the accuracy and comprehensibility of both single lazy decision trees and boosted ensembles.
Correlation coefficient is an important measurement in data mining application. It reflects co-varying relationship between two random variables. Conventional methods assume the data set as crisp value, however many d...
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Correlation coefficient is an important measurement in data mining application. It reflects co-varying relationship between two random variables. Conventional methods assume the data set as crisp value, however many data in real world are ambiguous so it's not proper to define them as crisp value. In this paper, fuzzy set theory is introduced to deal with this problem. Since it's burdensome to compute fuzzy correlation coefficient precisely, we proposed an approximate method to estimate correlation coefficient for observations with fuzzy characteristics. Finally we did some simulation studies to verify this algorithm and compare the results with stochastic simulation method. Approximate estimation is very helpful for the purpose to have a preliminary knowledge of structure of data set in fuzzy environment.
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