In this paper, we proposed a scheme for TV news segmentation via exploring the efficient visual features. The proposed scheme can be divided into three parts, such as shot change detection based on skin color; probable anchorperson shot detection and anchorperson detection. According to experimental results, our proposed method can efficiently decompose TV news into anchorperson shots and report shots. Compared to the traditional face detection methods, the proposed method can robustly exclude the non-anchorperson shots in report shots such as the interview scenes. Experimental results are given to demonstrate the feasibility and efficiency of the proposed technique.
A new scheme to control the transmission power, allocate subcarriers,
and choose modulation schemes for each mobile terminal in a multiuser
OFDM system is investigated in this work. This proposed scheme attempts to make OFDM systems more flexible and robust to channel variations along time. The problem is decomposed to two stages. In the first stage, we maximize the minimum signal-to-noise ratio (SNR) of subchannels subject to constraints. The total system performance should be maintained at an acceptable level in this stage. Based on the result of the first stage, we choose modulation schemes for subchannels of each mobile terminal with an objective to maximize the total transmission rate while satisfying the performance requirement of each mobile terminal in the second stage. Simulations are conducted under a varying number of mobile terminals with a range of symbol error rates (SERs). Simulation results show that the proposed scheme works well under certain operating environments.
A statistical approach to distributed edge detection in wireless sensor networks is proposed in this research. Rather than trying to estimate the real edge of a phenomenon, the technique of edge sensor detection is adopted to determine whether a target sensor is located within the edge area or not based on information collected from its neighboring sensors. Due to the nature of wireless sensor networks, it is desirable to have a distributed algorithm that has a low computational complexity and a low data communication cost among sensors. With some reasonable assumptions and the aid of composite hypothesis testing, we propose data fusion as well as decision fusion methods for edge sensor detection to fulfill the aforementioned constraints. Numerical experiments are used to demonstrate the efficiency of the proposed algorithm.
A new scheme to control the transmission power, allocate subcarriers, and choose modulation schemes for each mobile terminal in a multiuser OFDM system is investigated in this work. This proposed scheme attempts to make OFDM systems more flexible and robust to channel variations along time. The problem is decomposed to two stages. In the first stage, we maximize the minimum signal-to-noise ratio (SNR) of subchannels subject to constraints. The total system performance should be maintained at an acceptable level in this stage. Based
on the result of the first stage, we choose modulation schemes for subchannels of each mobile terminal with an objective to maximize the total transmission rate while satisfying the performance requirement of each mobile terminal in the second stage. Simulations are conducted under a varying number of mobile terminals with a range of symbol error rates (SERs). Simulation results show that the proposed scheme works well under certain operating environments.
KEYWORDS: Modulation, Orthogonal frequency division multiplexing, Signal to noise ratio, Control systems, Computer simulations, Adaptive control, Multimedia, Systems modeling, Phase shift keying, Data communications
A new scheme to control the transmission power, allocate
subcarriers, and choose modulation schemes for each mobile terminal in a multiuser OFDM system is proposed in this paper. This scheme will make OFDM systems more flexible and more robust to the channel variation along time. We divide the problem into two stages. In the first stage, we maximize the minimum signal-to-noise ratio (SNR) of subchannels subject two constraints. The total system performance can be maintained to an acceptable level in this stage. In the second stage, based on the result of the first stage, we choose the modulation schemes of subchannels of each mobile terminal in the hope that the total transmission rate can be maximized and the performance requirement of each mobile terminal can be satisfied. Simulations are
conducted under a different total number of mobile terminals and a different SER (symbol error rate) requirements. Simulation results show that the proposed scheme works well under the simulated environments.
This paper gives the complete analysis of SINR when using OVSF/truncated PN codes in downlink channel for multi-rate W-CDMA systems in a multi-user and multi-path fading environment when RAKE receiver is used at the mobile end. We point out those terms ingored under the situation that the autocorrelation property of PN sequence holds in previous work. Then we give simulations to show the reasons why these terms can not be omitted, and give appropriate mathematical representation to model these terms. At last, we give the comparison of the analytical result of SINR formula and numerical result in different cases. The simulations have shown that by taking these terms into consideration, we can have better fit to the numerical result.
A packet-based power control scheme is proposed in this paper. The proposed power control scheme aims at minimizing the total number of transmission that a packet needs before it is received successfully over a Rayleigh fading channel subject to two constraints. One is that the transmission power should be greater than zero. The other is imposed by the constraint on the total transmission power at the base station. We use the augmented Lagrangian multiplier method to solve this problem and provide a theoretical solution. The simulation results show that, with the proposed power control scheme, the number of re-transmission can be reduced and the delay of a packet wasted in the channel can be decreased as well.
KEYWORDS: Multimedia, Control systems, Systems modeling, System integration, Analytical research, Video, Complex systems, Chemical elements, Electrical engineering, Signal attenuation
A new power control scheme for downlink CDMA transmission by using an outage probability criterion is proposed in this research. We first analyze the outage probability when data are transmitted over shadowing and Rayleigh fading channels. Then, the power is assigned to each link of the system so that the overall outage probability is minimized subject to three constraints. They are the total transmission power at the base station, the maximum transmission power for each user, and the maximum tolerable outage probability for each user. The Newton-Raphson algorithm is modified to solve the minimization problem under these constraints. Experimental results demonstrate that the proposed algorithm is capable of differentiating QoS requirements for each link in addition to improving the throughput of the system.
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