Papers by Keyword: Asynchronous

Abstract: Space-time two dimensional RAKE receiver was introduced into asynchronous and cooperative communication system, and a high-performance RAKE receiving algorithm was proposed. In this algorithm, the transmitting signals were estimated coarsely by traditional space-time rake receiver, then each multipath signal was reconstructed using the estimated result as well as the channel impulse response, and then eliminated successively from reception signals, so it can eliminate Inter Symbol Interference of receiver signals which generate by multipath fading, and the line of sight (LOS) component in the received signal was obtained, and finally, the space-time combination was carried out to the LOS component, and the spatial diversity was achieved. This algorithm can effectively reduce the bit error rate of the asynchronous cooperative communication system. Simulation result shows that the new algorithm can improve the performance of traditional space-time RAKE when SNR is higher than 5dB dramatically.

Abstract: A high-performance space-time two dimensional RAKE receiving algorithm was proposed in asynchronous cooperative communication system. the transmitting signals were estimated coarsely by traditional space-time rake receiver, then on the basis of that we introduce feedback technology, each multipath signal of transmitted signals was composed by the decision results, and then every multipath component in the received signal can be obtained by eliminating the composed multipath signals from the received signal. Finally, the multipath components were combined by space-time combination and multipath combination rules accordingly, so spatial as well as multipath diversities were achieved. Simulation results show that the new scheme can reduce the bit error rate dramatically compare with traditional space-time RAKE in asynchronous cooperative communication system.

Abstract: The sparse and mobility of nodes in opportunistic networks will cause network topology often fracturing, resulting that a large number of isolated nodes appear in opportunistic networks. These isolated nodes will waste much energy at idle listening stage, so this paper proposes an Efficient Routing algorithm for opportunistic networks based on Asynchronous Sleep Approach-ERASA. ERASA achieves the goal of saving energy by making the isolated nodes enter the low power consumption dormancy state. Then they will be timely awaken when there are other nodes entering into their communication range. Compared with the classical Epidemic routing algorithm, the several aspects performance of ERASA algorithm are improved such as network lifetime.

Abstract: This paper analyzes the three major problems exist in the long-term use of hydraulic coupler, a temperature rise effect is the hidden trouble of the normal operation of equipment; two is the site difficult to accurately control the charging liquid, starting power balance and shutdown can not control the scraper conveyer; three is the property of medium effects factors of hydraulic coupling torque; introduces the working principle of asynchronous magnetic coupling and unique five technical characteristics. The asynchronous magnetic coupling and hydraulic coupler has obvious technical advantages compared, can solve the long-standing hydraulic coupler in the production practice expect to solve urgently and has failed to solve the problem. Conclusion is the soft starter for asynchronous magnetic coupling for scraper conveyor is completely feasible.

Abstract: In this paper, design and implementation of SOPC (System on Programmable Chip) based Asynchronous pipelined Discrete Cosine Transform (DCT) is considered. For designing Asynchronous Pipelined DCT, a new approach is proposed. In this approach, Nios II embedded processor is used to control the asynchronous data flow. For implementation of Asynchronous pipelined DCT, Winograd algorithm with 6 stages (Combinational Logic Blocks) of operations is used. The intermittent data between stages are latched by using multiplexer based latches. The completion of each and every stage is informed to the Nios II processor using interrupts. In turn, Nios II processor generates various control signals to pass the intermittent data stored in the multiplexer based latches. In the proposed system, storage of intermittent data is done with multiplexer based latches instead of registers. This leads to minimum power consumption. The system is useful in water marking the patient details on to the patient records to transmit through Internet. The work has been carried out as a part of embedded remote patient monitoring system, in which the measured medical parameters and images of the patients are to be sent to the remote doctor through wired or wireless medium, along with the patient details. The system is implemented in EP1S25F780C5 Altera Stratix FPGA with Nios II embedded processor. Importantly, Nios II processor is also used to validate the DCT & IDCT results by comparing the results with a known set of test vectors.

Abstract: The deployable structure of the ring truss have advantage properties, which can be used as an effective supporting structure of deployable antenna. The deployable experiment of ring truss antenna showed that there was asynchronous phenomenon at the course of the deployment. Dynamics theory including constraint equations and considering friction factor are built firstly. Then simulation is studied systematically for the deployment process of ring truss deployable antenna. At last, the conclusions are obtained that the friction insulted in tensile forces of the cable drive decrease and the asynchronous phenomenon in the process of the deployment. It will give some help to the design and manufacture of the ring truss antenna.

Abstract: This paper presents a low power ΣΔ modulator for a low power microsensor application. The ΣΔ modulator adopts second-order single loop topology with input feed-forward path. An asynchronous 4-bit successive approximation (SAR) quanztizer is employed to digitize the analog input. Inherent summation of SAR quantizer is utilized as analog summation. The switched operational amplifier is used in first integrator to reduced power consumption. The modulator, simulated at the transistor level using 0.13-μm CMOS technology, obtains a peak SNDR of 93 dB over an input signal of 5 kHz and simulation power consumption is 340 μW from 1-V supply.

Abstract: AJAX is a new technology, which was published by Java community in 2005, and immediately cried up by programmers. AJAX integrates many matured techniques. The characters are synchronous dealing with UI element in client side, asynchronous sending message to server, accepting data, then only updating the elements which need to be updated, no need to update the whole page. This new mechanism enhances B/S efficiency greatly. The author has applied AJAX to WebGIS project and the effect is great. This paper introduces work theory of AJAX and technique rout to apply it to WebGIS.

Abstract: Transmission performances of some squirrel cage magnetic couplings, which were different in magnet pole number, slot number, slot depth or slot area, were tested. Experimental results and analysis indicate that these parameters (magnet pole number, slot number, slot depth and slot area) all affect transmission performance of a squirrel cage magnetic coupling. In these factors, deep slot can not only increase slot area to improve a squirrel cage magnetic coupling’s transmission performance, but also can make skin effect on conducting bars more obvious to further improve the transmission performance. Therefore, slot depth affects transmission performance of a squirrel cage magnetic coupling greatly. The experimental results show that a deep slot squirrel cage magnetic coupling’s transmission performance is much better than a common one.

Abstract: This paper describes the Ajax technology as well as asynchronous communication model and the traditional model’s difference, discusses the Ajax technology’s application in network teaching resources library system, implements asynchronous data transmission in the case of no page refreshing, enhances interactive of network teaching resources library system, and improves the efficiency of the network teaching resources server. At the same time, this paper also analyzes the adverse factors; this has certain guide significance for the use of Ajax technology to develop network teaching resources library.