Applied Mechanics and Materials Vols. 427-429

Abstract: This paper Clarifies the basic ideas of constructing the v order Steiner triple systems. This paper proposed the construction method of pairwise disjoint sets s⁽ⁱ⁾(v) for Steiner triple systems based on the initial block permutation matrix. And a method of initial block permutation matrix is given. This paper also introduced the entire construction process of two isomorphic 9 order Steiner triple systems large set. At last, this paper proved the number of pairwise disjoint forsⁱ(9)is d(9)=7 .

Abstract: Focused on the communication system of differentially encoded binary phase-shift keying (DBPSK/2DPSK), this paper studies on the influences of inter symbol interferences (ISI) on the bit error rate (BER) performance and derives the BER expression that is applicable for arbitrary sending probabilities of binary symbols using the knowledge of integration and probability theory, which is then demonstrated to be correct by the Monte Caro simulation method.

Abstract: Automatic Variable Transmission (AVT) is composed of a metal belt CVT unit and a step speed changing transmission component. According to the needs of automotive conditions, AVT can realize continuously variable transmission and gear transmission, which not only play the advantage of gear transmission efficiency, but also overcome the deficiency of CVT when it is in high-speed. In the paper, the transmission matching rule is introduced, and engine model is established using engine test data. Based on SimulationX software, a vehicle that equips AVT is used for modeling and simulation. Finally the power matching is researched.

Abstract: The converter can supply auxiliary power and ensure bus balances on the hardware. The converter used design method of single-ended flyback, clamping-diodes balanced the positive and negative buses. The design plan and parameter are described. The practice shows that the circuit can provide auxiliary power capability of 60W and the uneven degree of the positive and negative buses is 1.8V. The circuit can be used in any switching power supply, whose bus voltage range is ±(260-450)V.

Abstract: Gas detection alarm system plays a more and more important role in People's Daily life and every field. This paper proposes semiconductor gas sensors and SCM as the core, which could achieves the gas concentration monitoring and alarm functions. The gas monitoring system includes host computer that consists of LabVIEW operating interface and slave computer that constructed with AT89C51 microcomputer and MQ-2 gas sensor.It achieves remote monitoring and controlling housing environment in real-time and has a certain practical value in society.

Abstract: To estimate the spreading sequences for DS-CDMA system, a blind estimation method based on improved Fast-ICA is proposed. In this method, the ECA whitening and BAT optimization are introduced into the traditional Fast-ICA firstly, then the improved Fast-ICA is used to obtain spreading sequences matrix, finally, the spreading sequences are extracted from the spreading sequences matrix. Simulation results show the validity and superiority of the new method.

Abstract: The characteristics of PID controller, Active Disturbance Rejection Controller (ADRC) and Linear Active Disturbance Rejection Controller (LADRC) are introduced in the paper, then the parts which can be improved are analyzed, which leads to the topic of balancing linear and nonlinear elements in controller. LADRC with FFTD is used as an example in simulation experiment operated in Matlab7.0.The results shows that the control effect of LADRC with FFTD is better than other three controllers above. The simulation results and perspectives in paper offers reference for combining linear and nonlinear controller and balancing difficulty and performance.

Abstract: In view of the existing flaws of traditional manual observations, a new type of tailing reservoir safety monitoring and warning system based on ZigBee and LabVIEW was designed. The system chose SoC chip CC2530 as the RF transceiver and designed the low-power wireless sensor networks nodes to collect and process the data of tailing reservoir. It chose ZigBee 2007 as the network communication protocol, and uploaded the data to PC by RS232 serial port. The monitoring and warning interface of PC was completed with LabVIEW. The testing results show that the data transmission of the network is stable and the system is suitable for real-time monitoring and warning of the tungsten tailing reservoir.

Abstract: The need for mobility and the rapid deployment motivates the research of distributed radar sensor network with N_T transmitters, N_R receivers and a fusion center, where the fusion center and the receivers are communicated via wireless signaling. With the assumption of orthogonal waveforms for sensing and circular complex Gaussian noise channel model for communication, the formulae of detection probability and the false alarm probability are derived given the sensing power and communication power. Numerical results show that with the increase of the total power, the ratio between the best sensing power and the best communication power will increase. Moreover, the shape of the region in which the target detection probability is larger than a predetermined value is not regular, which should be taken care in case of network planning.

Abstract: SPI NOR Flash is widely used in embedded system for its compact package and simple interface. It is suitable to medium scale data storage. Now, industry provides higher density NAND Flash with the same interface and package as SPI NOR Flash. But the erase/program circles of NAND Flash is less than that of NOR Flash. The lifetime of NAND Flash is becoming the critical issue. Wear leveling algorithms prevent NAND Flash from prematurely retiring by mapping the logical block to different physical blocks. To our knowledge, most wear leveling algorithms need several kilobytes of RAM for keeping the mapping data structures, which is costly for the resource constrained micro controller. This study first proposes a no RAM required design with presetting lifetime, and then presents an adaptive design which requires only 2 kilobytes RAM with elasticity lifetime. The proposed design can be adapted in most of embedded systems based on low cost micro controller.