Applied Mechanics and Materials Vols. 411-414

Abstract: Recently, more and more companies are using wireless location technology to improve advertising effectiveness. Although location-targeted advertising seemingly offers practitioners tremendous potential given the ubiquitous nature of mobile devices, we know very little about it. Base on field experiment data, the developed zero-inflated Poisson model reveals that distance, discount and CSR(Corporate Social Responsibility) could affect sales impact of advertising while using wireless communication technology. These results have implications for mobile marketing research and practice while using wireless communication technology.

Abstract: Voice activity detection (VAD) is more and more essential in the noisy environments to provide an accuracy performance in the speech recognition. In this paper, we provide a method based on left-right hidden Markov model (HMM) to identify the start and end of the speech. The method builds two models of non-speech and speech instead of existed two states, formally, each model could include several states, we also analysis other features, such as pitch index, pitch magnitude and fractal dimension of speech and non-speech.. We compare the VAD results with the proposed algorithm and two states HMM. Experiments show that the proposed method make a better performance than two states HMMs in VAD, especially in the low signal-to-noise ratio (SNR) environment.

Abstract: With the development of satellite laser communication, modulation scheme has been the key technique for the modulation subsystem. The performance in terms of bite-error rate of OOK, 2DPSK, QDPSK used in the downlink of the ground-to-satellite laser communication systems are compared with the consideration of the combined effects of both intensity scintillation and detector noise. Simulation results are given and the advantages and disadvantages of the three modulation schemes are also studied. The design of the downlink of ground-to-satellite laser communication system can benefit from this work.

Abstract: With the consideration of the intensity scintillation caused by the atmosphere turbulence in the downlink of the ground-to-satellite optical communication system, BER performances of three different modulation schemes OOK, 2PSK, QPSK are explored and compared. Simulation results are given and conclusions are achieved through the discussions of the advantages and disadvantages of various schemes, which may cause contributions to the selection of the modulation format in the design of the ground-to-satellite laser communication system.

Abstract: In this paper, the bit-error rate (BER) performance of on-off keying (OOK) and minimum shift keying (MSK) formats with two kinds of demodulation methods in a typical downlink of ground-to-satellite optical communication system affected by atmospheric turbulence is analyzed and compared. In addition, numeric simulation is carried out and the relationships between BERs and laser emitting power, divergence angle, zenith angle and diameter of receiving aperture are obtained and analyzed. The results show that MSK with delay coherent demodulation (DCD) is better than OOK and coherent demodulation (CD) in BER performance and power spectrum.

Abstract: We numerically solve the Haus master equation by split Fourier transform method under Fortran and MATLAB environment to investigate the role of the modulation depth in a mode-locked all-fiber erbium laser with normal cavity dispersion. Through our simulation, we have demonstrated that the modulation depth of the saturable absorber (SA) significantly affects the mode-locking energy, per pulse energy, pulse duration and spectral bandwidth at the laser output for a given cavity design.

Abstract: We present an SDN-based control plane for elastic optical wavelength switch in optical networks, for dynamic end-to-end lightpath provisioning and maximum flexible operations. Detailed architecture and specific modules including underlying wavelength switch, SDN controller and applications are developed and evaluated to show its overall feasibility and efficiency.

Abstract: The theory analysis of the (7, 4) binary hamming coding and decoding algorithm in spread spectrum communication is given and implemented with C language programming. The verification testing is implemented on a HD 111 communication principle platform. The theory results are in consistent with that of the experiment. It shows that (7, 4) binary hamming coding could rectify one error symbol which would emerge in the signal transmission process.

Abstract: This paper is mainly to introduce The Short Message Peer to Peer (SMPP) protocol, and one of it’s major application to Unstructured Supplementary Services Data (USSD). The author intends to utilize SMPP protocol to realize a basic USSD Session flow.

Abstract: Orthogonal Frequency Division Multiplexing (OFDM) is the key technology of high speed communication systems which are widely used today. Small carrier frequency offset can make OFDM system performance fell sharply. So it needs very effective carrier frequency synchronization to make sure that the system works perfect. Seen from a large number of simulations, typical algorithm requires strict symbol timing. According to this characteristic, we proposed an improved carrier frequency synchronization algorithm using cyclic prefix. The improved algorithm can achieve better performance than typical algorithm in multipath fading channel. The precision of the improved algorithm under the same Signal Noise Ratio (SNR) is about 3 orders of magnitude higher than typical algorithm. We found that improved algorithm has more excellent performance in burst packet transmission mode.