Applied Mechanics and Materials Vols. 713-715

Abstract: The long term evolution (LTE) is a promising candidate solution for smart grid communication network due to its high data rate, lower latency, high mobility, and large coverage. In this paper, we discuss three resource scheduling algorithms for the LTE-based smart grids, including proportional fairness, round robin, and maximum rate scheduling schemes. In the simulations, we compare these three resource scheduling algorithms, the results show that the proportional fairness scheduler can achieve the best tradeoff between the average sum rate and the fairness among all the users.

Abstract: The operation of power system generates a huge number of data. Manual screening of bad data is almost impossible to achieve. Bad data detection of the power system is the essential prerequisite for power system state estimation. So combined with the characteristics of bad data of the power system, this paper puts forwards an improved K-Means algorithm based on PSO. The traditional K-Means algorithm has disadvantage that it has low efficiency to determine the cluster’s center, but PSO algorithm has the ability to determine the cluster’s center quickly and accurately, this paper combines them together and take advantages of each of the two. The improved K-Means algorithm is based on PSO and verified the effectiveness of the algorithm. The results satisfy the requirements of screening bad data and reduce the false alarms and the probability of undetected and improve the recognition efficiency.

Abstract: The long term evolution (LTE) based smart grid communication network is a promising candidate solution for the future power grid. In this paper, we discuss three channel estimation schemes for the LTE-based smart grids, including least square (LS), minimum mean square error (MMSE), and discrete Fourier transform (DFT) based channel estimators. In the simulations, we compare these three estimators, the results show that the DFT-based channel estimator can achieve the best tradeoff between the performance and the implementation complexity.

Abstract: The purpose of this paper is to design a family or battlefield independent rescue system which is based on passive sound source localization and machine vision, The system consists of five modules: the sound acquisition and processing module based on FPGA, image acquisition and processing module based on TMS320DM6437, video capture and communication control module based on TMS320DM355, motion control module based on MSP430F149, PC server and smart handheld mobile client. It can track target person who need help automatically by recognizing his voice and image, to provide emergency medicines, communication tools, and transmit real-time video information to a server on PC and a mobile client on Andriod platform by wireless network, and be controlled remotely.

Abstract: In view of the digital geophone self-test system application demand for a variety of high quality waveform signal. This paper introduces a kind of design method of direct digital synthesis waveform signal generator based on FPGA. It mainly discusses the principle of the method of frequency synthesis technology, design thinking and implementation method. And using the design method of pipeline structure to improve circuit structure of 48 bits phase accumulator, so as to improve the running speed, and further increase the resolution of frequency synthesis. The test shows that the signal generator can produce sine wave, square wave, sawtooth wave, triangle wave. The frequency resolution can reach 0.18μHz. The highest output frequency is up to 20MHz, and frequency switch time is 20ns.

Abstract: In this paper,the relationship between 50% ac flashover voltage (U₅₀) of long porcelain insulator string and ρ_ESDD and ρ_NSDD was analyzed based on experimental results. It was shown that the relationship between U₅₀ and ρ_ESDD is the same as the one between U₅₀ and ρ_NSDD, in which the U₅₀ reduces with the increase of ρ_ESDD by a power function, and the influences of ρ_ESDD and ρ_NSDD on U₅₀ are mutually independent. By using the least square method, the value of exponent of a and b were determined.

Abstract: It is used by the research platform based on the N32926 development board of Nuvoton Company, achieved the real-time capture and display of video. It is chosen RT-Thread as its operating system on the development board. It can be captured images video system by used OV7725 camera and then encoded these images with H.264, finally it can be decoded the images and convert the YUV data into RGB format and displayed.

Abstract: Real-time precise IOT positioning system based on CSS uses the way of bus or Ethernet with wireless CSS network. With its unique CSS technology to measure the distance, the console can achieve real-time communication and position monitoring of personnel and goods. The system has better comprehensive performance than active RFID, Zigbee and WiFi positioning systems and other technology on the market currently. The functional independence of its communication system makes it easy for the practical application and extensions, and the system has wide application value.

Abstract: STC89S52 single-chip microcomputer is the control core of intelligent wagon which can automatically enter into garage, which can control direction and speed of the wagon through collection and processing of signals from various sensors on the route in the forward direction, and thus can realize some functions including rapid and stable running through automatic recognition of black guiding line as well as entering into garage through recognition of light source. In addition, voice and light prompting device is used to prompt the action of entering into garage and the exact heading direction of the wagon, namely due west. Moving and turning of the wagon is driven by DC motor, and motor should be driven by L298N driving chip, which has high control accuracy and flexibility in turning. LCD1602 screen is used to display time of running and angle of turning. In addition, design, programming and program debugging for the entire control software are carried out, and the final integration of software and hardware can be realized, based on which intended functions of the wagon can thus be realized.

Abstract: In order to pinpoint the location of the crew, master the number, location and distribution of personnel and activity track of time period, designed personnel positioning system of the ship based on zigbee technical by the gateway node, reference node, locate nodes, and designed personnel positioning system software in the IAR development environment. RSSI location algorithm has been improved, and the improved positioning algorithm using Matlab simulation to test, the test results show that the improved algorithm has higher positioning accuracy.