Applied Mechanics and Materials Vols. 198-199

Abstract: In UWA (underwater acoustic) communications, data rate is severely limited by the confined bandwidth source of aquatic channel. MIMO (Multiple-input Multiple-output) techniques can drastically improve the spectral efficiency, and have been a new point of reference in UWA commutations. For the estimation of UWA channel which is usually sparse, CS (compress sensing) along with STBC (space-time block code) is adopted with improved results. A design of mixing coding MIMO-OFDM is also presented in the proposed method. The validity and the dependability of this scheme are verified by Monte Carlo simulations.

Abstract: Applying the Internet of Things (IOT) into ecological environmental monitoring is the goal of this paper. There are several advantages of the Internet of Things (IOT) applying in ecological environment monitoring. A hierarchical monitoring system is presented, including system architecture, hardware/software design, information flow and software implementation. In the end, using carbon dioxide gas in the atmosphere for experimental purposes, in data collection and analysis. Experiments showed that this system is capable of monitoring ecologica environment, which orientate the future research of forest ecosystem.

Abstract: The communication rate is limited extremely by the confined bandwidth source of UWA (underwater acoustic) channel. MIMO (Multiple-input Multiple-output) techniques can drastically improve the spectral efficiency, and have been a new hot spot in UWA commutation. To estimate the UWA channel STBC (space-time block code) technique is adopted, and the improved method of channel estimating is also given. A designed of complex coding MIMO-OFDM is provided.The validity and the dependability of the scheme are verified by Monte Carlo simulations.

Abstract: Compared with the traditional direct sequence spread spectrum technology，Multi-band Spread Spectrum have great advantages. According to the basic principle of Multi-band Spread Spectrum, this paper Established the Multi-band Spread Spectrum system model, discusses the signal detection problems in terms of multi-band spread spectrum. Based on the results, it obtained the ruling methods of Gaussian white noise channel under multiple symbols detection and binary bits detection and likelihood ratio information theoretical expressions. And it finds that the two tests have the same mistake-symbol performance through the simulation. The experimental results show that multiple symbol detection and RS code used in conjunction with will achieve better performance.

Abstract: Aiming at the defects of traditional heating boiler control systems, in Geographical limitations, waste of human resources etc. We combines Web technology with traditional heating boiler control strategies, developed a B/S,C/S mixed-mode control system, that allows workers look up data and control heating boilers from Website safely, no matter where the heating boiler located. Website is developed in ASP.NET, other programs are developed in VC++.NET. This system can improve management and production efficiencies, reduce human resources and operating costs.

Abstract: The control of water level and flow for channel irrigation system has nonlinear, time-varying and uncertainty characteristics. It is difficult to get satisfactory effect with traditional PID control. Aim at these features, this paper introduces a control method based on fuzzy neural network PID. This method both has advantage of PID control and has ability of fuzzy neural network self-learning and processing quantitative data. The control method can adjust the parameters of gate flow on-line quickly and efficiently and has good control effect and precision. The simulation results show the validity and correctness of the control method.

Abstract: As a dedicated digital mobile communication system designed for railway application, GSM-R must provide reliable bidirectional channel for transmitting security data between trackside equipments and on-train computer on high-speed railways. To ensure the safety of running trains, redundant network architecture is commonly used to guarantee the reliability of GSM-R. Because of the rigid demands of railway security, it is important to build reliability mathematical models, predict the network reliability and select a suitable one. Two common GSM-R wireless architectures, co-sited double layers network and intercross single layer network, are modeled and contrasted in this paper. By calculating the reliabilities of each reliable model, it is clear that more redundant the architecture is, more reliable the system will be, the whole system will bear a less failure time per year as the benefit. Meanwhile, as the redundancy of GSM-R system raises, its equipment and maintenance will cost much, but the reliability raise gently. From the standpoint of transmission system interruption and network equipment failure, the reliability of co-sited double layer network architecture is higher than the intercross single layer one, while the viability and cost of the intercross redundant network is better than co-sited one in natural disasters such as flood and lightning. Taking fully into account reliability, viability and cost, we suggest that intercross redundant network should be chosen on high-speed railway.

Abstract: By analyzing the characteristics and working principles of DSP series chip and TI’s RF chip, choose TMS320F2812 and CC2530 to realize data acquisition and wireless transmission. By SCI interface, the device finishes the data transmission between DSP and CC2530 ,and the wireless transmission between two CC2530 chips . In the paper , first introduce the hardware and software design of the device and then prove the feasibility of the device by drawing waveform of actual datum which are transmitted and received using the device .

Abstract: The fundamental theories of OFDM and WPM have many similarities in their functions and performance but there are some significant differences which give two systems to be distinctive. OFDM signals only overlap in the frequency domain while the wavelet signals overlap in both time and frequency domain. In the paper, WPM instead of conventional OFDM is used in WIMAX system. The simulation results show the WPM on WIMAX has lower bit error rate compare to conventional OFDM WIMAX.

Abstract: Cable telemetry transmit is a main way of data transmission in well logging systems .In this paper,due to a variety of shortcoming of logging cable, such as low transmit speed and narrow bandwidth, a DMT technology with the application of ADSL Wide Band is presented . This technology is analyzed theoretically in detail,and it has been proved that this method is feasible in increase the bandwidth using efficiency of the cable by compute emulation.