Advanced Materials Research Vols. 532-533

Abstract: MD5 Crypt is a cryptographic algorithm used commonly in UNIX system for authentication. Thanks to the additional randomization of the salt and complexity of the scheme, it makes the traditional password cracking techniques invalid on common computing systems so that the security of the system is guaranteed. As a result of the thriving of petaflops heterogeneous supercomputer system in recent decades, the security of MD5 Crypt is facing a threat of brute-force attack again. However, the complexity of heterogeneous programming and the sophistication of large-scale parallelism still hamper the password recovering. In this paper, we implemented brute-force attack of MD5 Crypt on Tianhe-1A，the world’s fastest supercomputer， by organizing the assignment between CPU and GPU reasonably and making several optimizations according to MD5 Crypt for GPU. Based on the experimental results, our algorithm achieves a great scalability. It checked more than 1.8 billion passwords in a second on the full system. Thus it issues a new challenge to the security of MD5 crypt for authentication.

Abstract: Agricultural information technology (AIT) has been broadly applied to every aspect of agriculture and has become the most effective means & tools for improving agricultural productivity. As an important sub-technology of AIT, the using of technology of Information Acquisition directly affects the degree of agricultural informatization and accuracy of agricultural production’s decision. In this paper, on the basis of introducing the characteristics of farmland production and traditional data collecting method, the designing architecture of farmland information acquisition system and related core technologies was discussed in detail.

Abstract: Choosing Features of a text is an important part of text categorization. Its result can affect the quality and efficiency of the text categorizer. Since there are usually thousands of features of a text, it always needs to reduce the dimension of the feature space. Considering the semantic relationship among words, a new text categorization method based on features clustering is proposed in this paper. This method first uses word segmentation to split texts into words, then, remove stop words and words with low information, and then calculate the distribution of words in these texts to construct a matrix of co-occurrence words. After that, cluster algorithms are employed to reduce the dimension of the feature space. Finally some experiments are carried out on two corpuses using several text categorization algorithms. The results demonstrate that this new method can not only improve the precision and recall of text categorization, but also increase the efficiency.

Abstract: A new pixel collecting interface board based on FPGA is designed, it is a part of conveyer belt’s fault detection device. The previous system’s controller chip CPLD is replaced by FPGA, the memory FIFO chips are replaced by SRAM, the chip CY7C68013 is chosen as the USB 2.0 controller and works in Slave FIFO transmission mode. The firmware program and application program are compiled to transmit data. The Chipscope Pro Tools are used in the system to debug online, and the correctness of data transmission can be analyzed and verified. The experimental results demonstrate that the new pixel collecting interface board has the advantage of high-speed data acquisition, and can transmit data in real time and correctly. It also has a good scalability and can be used into other high-speed acquisition systems.

Abstract: The internet of things is a network designed for connecting things together, which is established on the basis of computer network, as well as by making use of the RFID, wireless data communication technology, etc. Among all these technologies, RFID plays a crucial role in the construction of the internet of things. So far, the RFID technology has been widely used in industry, commerce, intelligent transportation system, and many other fields.

Abstract: This paper proposes a new method for automatic ship targets detection in remote sensing images. The method uses adaptive segmentation algorithm for getting possible ship targets first, and then calculates Histograms of Oriented Gradient (HOG) feature to extract the structural information of ships, followed by supervised learning algorithm to identify the possible ship targets. Multi-scale sliding-window is used to handle targets with different scales. The experimental results prove that this new method has a good precision and robustness for most of the ship targets and give attention to the efficiency.

Abstract: As one of the most advanced research field, the problem of SoC (System on a Chip) design is getting more and more attention. With the promotion of its theory and technique, SoC verification turns to one of the most significant part in the procedure of realizing a usable integrated circuit. And verification using FPGA (Field Programmable Gate Array) which must obey a set of strict technological process is a kind of general way. With the growing complexity and integrated scale of SoC design, a single FPGA chip could hardly satisfy the verification requirement. Then the method of verification using multi-FPGA is taken and expresses some advantages in some respects. Multi-FPGA verification is still in the initial step situation and has a broad developing space. The architecture of multi-FPGA verification platform is given in this paper, as well as some related key technical problem and solutions.

Abstract: This paper introduces a parallel FDTD (Finite Difference Time Domain) algorithm based on MPI (Message Passing Interface) parallel environment and NUMA (Non-Uniform Memory Access) architecture workstation. The FDTD computation is carried out independently in local meshes in each process. The data are exchanged by communication between adjacent subdomains to achieve the FDTD parallel method. The results show the consistency between serial and parallel algorithms, and the computing efficiency is improved effectively.

Abstract: 1040 °C was studied during the period imposed 137MPa tensile creep nickel-base single crystal superalloys γ/γ' the evolution of two-phase approach. ANSYS finite element method is using a single crystal alloy with / without external load when the Von Mises stress in the gand γ' two phase distribution. The comprehensive analysis of the formula, the coefficient values usually experience, not very accurate, this article dealing with convolution Algorithm coefficient. This algorithm uses orthogonal crossover to generate initial population and uses elitist-crossover to increase the good patterns of the population and uses hybrid mutation to increase the ability of local and global optimization. It has shown fascinating results when being used in the optimization of multimodal function. The results showed that: In the creep period, the corresponding cubic γ' along the von Mises stress and strain energy density of the crystal face to form raft-like organizations.

Abstract: With the rapid development of wireless network technology, wireless networks have been widely used in many fields due to the flexibility of wireless access. However, in the field of video transmission, because the link state is instability and the transmission is easily interfered in wireless networks, the quality of video transmission is affected badly. In fading and shadowing channels, some users can’t watch the video normally. This paper provides an adaptive QoS solution of real-time video stream in wireless network, by adding a relay server it can provide multicast or unicast video stream satisfying multiple QoS for users with different network state. This solution has been successfully applied in Qingdao Public safety emergency video surveillance system.