Applied Mechanics and Materials Vols. 241-244

Abstract: The number theory based cryptography algorithms are the most commonly used public-key cryptosystems. One of the fundamental arithmetic operations for such systems is the large integer multiplication. The efficiency of these cryptosystems is directly related to the efficiency of this large integer multiplication operation. Classical multiplication algorithm and Karatsuba multiplication algorithm, and their hybrid, are among the most popular multiplication algorithms used for this purpose. In this paper, we propose a hybrid of Karatsuba and a classical-based multiplication algorithm, enhanced by a new number representation system. The new number representation, known as "Big-Digits”, is used to carry out the sub-multiplication operation in the new multiplication algorithm. Big-Digits has a compact representation with lower Hamming weight. As the result, the number of sub-multiplication operations for the multiplication algorithm that is based on the Big-Digits representation is significantly reduced. Our results show that the proposed multiplication algorithm is significantly faster than the classical, Karasuba and the hybrid of Karatsuba-Classical multiplication algorithms within the implementation domain of the public-key cryptography.

Abstract: This paper focuses on improving concurrent performance of a practical SSL VPN server program. Several common technologies were been used to achieve this, including processing network flow effectively by using readiness notification mechanism, using appropriate data structure to deal with I/O buffers, and implementing timers management module by priority queue. Through combining these technologies properly, the performance of the SSL VPN server program has been improved dramatically.

Abstract: Wireless communication environment is very complex, so it is difficult to modeling of MIMO channel. A MIMO channel model was brought forward which has frequency selectivity, and time correlation. Simulation shows this related channel capacity is consistent with theoretical channel capacity. So this model provides powerful implement for simulation of MIMO capability, analysis of system capacity and evaluation of performance.

Abstract: Abstract. Aiming at current problem of high computing overhead of encryption and authentication, this paper proposes a confidentiality and integrity protection method based on one time encryption. The method packages data block and verification data together, and then encrypts it. The confidentiality is guaranteed by traditional encryption mode and the integrity is guaranteed by decrypted verification data. Analysis and simulation show that the method has less time and space overhead than standard encryption and authentication mode. The method can be applied to other integrity and confidentiality protection schemes, and can meet the performance requirements of the most applications.

Abstract: For the problem of the throughput degradation and fairness deterioration of the conventional radio frequency (RF) allocation mechanism in “hot point” areas, this paper presented a novel RF allocation mechanism using radio over free space optics (RoFSO) technology. The proposed algorithm contained initial RF assignment and optimal RF assignment. The initial RF allocation was built on the distribution of adjacent remote access units (RAUs). In addition, the optimal RF allocation includes RF switching and RF scheduling, both of which were designed based on site-specific cognition of stations. Through the analysis of simulation results, we know that our proposed algorithm in RoFSO network outperform the conventional RF allocation algorithm in wireless local area network (WLAN) by 350%, 45%, and 90% for average goodput of each user, fairness index of entire network and average frame service delay (FSD), respectively.

Abstract: In this paper we studied timeliness of TDMA-based MAC scheduling mechanisms. TDMA-based MAC protocols require sensor nodes to deliver data individually so as to eliminate collisions in shared channel. This scheduling mechanism can assist sensor nodes in managing energy efficiently since data resending that collisions induced has a significant impact on battery life. But during medium access arbitration, the elected central node has to receive other nodes’ state messages one by one before assigning time slots for each node. While in large-scale sensor networks, the waiting time would be a relatively long duration and result in timeliness decrease in time-sensitive environments. We propose a novel time slots assignment algorithm for TDMA-based MAC protocols that allows sensor nodes to deliver state messages simultaneously to central node for medium access arbitration and present an analysis in which these two approaches are compared in respect to timeliness. The algorithm is evaluated through simulation. Simulation results have confirmed the timeliness of our new algorithm.

Abstract: In this paper, we present multiple bit error correction coding scheme using extended Hamming product code combined with type II HARQ and keyboard scan based error flipping to correct multiple bit errors for on chip interconnect. The keyboard scan based error flipping reduces the hardware complexity of the decoder compared to the existing three stages iterative decoding method for on chip interconnects. The proposed method of decoding achieves 86% of reduction in area and 23% of reduction in decoder delay with only small increase in residual flit error rate compared to the existing three stage iterative decoding scheme for multiple bit error correction. The proposed code also achieves excellent improvement in residual flit error rate and up to 66% of links power consumption compared to the other error control schemes. The low complexity and excellent residual flit error rate make the proposed code suitable for on chip interconnection links.

Abstract: A reliable management system based on RFID was introduced to ensure the more efficient and effective operation of laboratory.In this system, reader/writer is on the basis of MFRC522;P89LPC932 is used as access controller; control nodes communicate with center server based on RS485 and TCP/IP ; development platform is based on Visual Studio2010 and database is established on SQL Server2008. This system has high reliability and good real-time capability because of the distributed structure and centralized control.

Abstract: SpaceWire is a high-speed, full-duplex serial bus standard which is applied in aerospace, so its functions require high accuracy. The traditional methods of verification, such as simulation and test, are not complete. In order to prove the design of the SpaceWire faithfully implemented the SpaceWire protocol’s specification, we presented our experience on the model checking of SpaceWire data flow control using the Cadence SMV tool. It overcomes the incompleteness of traditional verification. And by injecting the errors to ensure the accuracy of the artificial extraction properties and completeness, comparison tests show that the method can effectively ensure the functional coverage, improve reliability of the verification.

Abstract: Security transaction problem between the client and the server was solved by a network identity authentication protocol of this paper. We designed this protocol from two aspects, one is the hardware structure design, and the other is data encryption. We used fingerprint sensor to gather the user’s fingerprint and characteristic value instead of password input from keyboard, and used RSA probabilistic encryption to generate public key and private key of the client and public key and private key of the server, and then used the protocol certification process to finish operation of the data encryption and decryption. This protocol guarantees every specific legitimate user rights and prevents the hacker from attacking network data, and the practical application shows this protocol is absolutely safe.