Applied Mechanics and Materials Vols. 543-547

Abstract: Traditional File Transmission Protocol (FTP) servers are not suitable for embedded environments since these servers take complicating factors into account and consequently take a lot of memory space. Moreover, some FTP server applications even manage all file transmission by utilizing graphic user interface. However, such server is not adequate for embedded environments. When embedded system needs is more memory-efficient efficient in a resource restricted system. To cope with this problem, in this problem we conduct research on lightweight FTP server for embedded systems. And, we first summarize features of a lightweight FTP server. Then, based on the design requirements for FTP server for embedded systems, a lightweight FTP server is designed. The server adopts a command-line user interface and other advanced features, such as transmission encryption and graphic user interface, are abandoned for efficiency reasons. Last, to evaluate our design of the FTP server, several experiments are conducted and all results show that the FTP server works quite well under embedded environments. With more and more embedded systems emerging in the industry, it can be expected that the software introduced in this paper will play a more and more important role in the industry.

Abstract: Superscalar processors contain complex control logic in order to extract sufficient instruction level parallelism (ILP). The issue logic is one of the main sources of power dissipation in current superscalar processors. It has been estimated that up to 30% of the energy consumed by a processor is in the issue logic. This paper presents a novel compiler assisted approach to power reduction where we use compiler analysis to pass information to the processor about the number of entries needed, allowing the processor to resize the issue queue dynamically which limit the number of instruction dispatched and resident in the queue reduces the energy consumption without adversely affecting performance. Compared with hardware scheme, our approach is simpler faster and saves more energy. Using the approach we achieve 43.3% dynamic and 28.5% static power savings.

Abstract: In order to improve real-time of MVB sporadic data communication, we study and analysis MVB sporadic data communication scheduling modelling and collision event arbitration mechanism, the communication maximum arbitration delay is closely related with concurrent message events, binary tree search algorithm mechanism bring out big communication delay, so, we makes use of multi-optimizing strategies, applying dynamically assigned communication of sporadic data and slave frame stuffing of process data, decreasing communication delay of sporadic data and making sure that emergent sporadic data firstly send, it is a good try to optimize real-time of sporadic data.

Abstract: The hybrid cellular automaton (HCA) algorithm is a gradient-free methodology that combines both local update rules based on the cellular automaton (CA) paradigm and the finite element analysis (FEA). The local update rules could determine the distribution of the material based on the local state information collected from cellular automaton paradigm. This paper proposes a modified update rule of field variable to suppress the mesh dependency and gray-scale elements problems occurred in topology optimization of continuum structures. Two typical numerical examples are presented to prove the effectiveness and robustness of the proposed method in solving the numerical instabilities problem.

Abstract: An error correcting method of BCH code applicable to memory is proposed. The reliability and yield of memories can be efficiently improved by error correcting codes. Due to the limited length of data transfer bits in certain interfaces, check bits are not fully used by most BCH codes. The proposed method takes advantage of the nature of BCH codes to make full use of the check bits, so that more errors can be corrected than the original method. The algorithm can be achieved by pure logic circuits in a parallel way with only gate delay, suitable for special timing applications. The improvement of certain BCH code is evaluated by C++ and the hardware implementation is presented by FPGA.

Abstract: The existing methods based on convex-optimization theory, which use the concept of SINR, can just design the optimal precoder for each user with single antenna. In this paper, we design the optimal precoding matrices for multi-user MIMO downlinks by solving the optimization problem that minimizes total transmit power subject to signal-leakage-plus-noise-ratio (SLNR) constraints. Because SLNR of each user is determined by its own precoding matrix and is independent of other users, the goal problem can be separated into a series of decoupled low-complexity quadratically constrained quadratic programs (QCQPs). Using the semidefinite relaxation (SDR) technique, these QCQPs can be reformulated into the semidefinite programs (SDP) and be solved effectively. Simulation results show that proposed precoding scheme is quite feasible when each user has two receive antennas, and it has better bit error rate (BER) performance than the original maximal-SLNR precoding scheme when SLNR of each user satisfies large threshold value.

Abstract: For the problem of poor transmission stability in HF channel, we builted a frequency optimization model based on the HF dynamic frequency optimization technology with working frequency, communication distance and time as dynamic elements ,with the type of antenna, the sunspots as static elements, choose the best working frequency set for communication according to the geographical location information, avoid interference channel effectively by real-time monitoring, and make sure communication service has always been on the best working frequency. Further enhancing the the validity and reliability of HF channel transmission.

Abstract: This paper investigated the method of Dynamic Spectrum Access (DSA) in cognitive networks, considering the PU channels both time-varying and fading. We used the Partially Observable Markov Decision Process (POMDP) framework to model this problem and designed a greedy strategy. The simulation results shows that the proposed strategy obtained better throughput performance than the existing works.

Abstract: The technique of a new extension of fuzzy rough theory using partition of interval set-valued is proposed for granular computing during knowledge discovery in this paper. The natural intervals of attribute values in decision system to be transformed into multiple sub-interval of [0,1]are given by normalization. And some characteristics of interval set-valued of decision systems in fuzzy rough set theory are discussed. The correctness and effectiveness of the approach are shown in experiments. The approach presented in this paper can also be used as a data preprocessing step for other symbolic knowledge discovery or machine learning methods other than rough set theory.

Abstract: Network intrusion is shown in more and more concealment, and some intrusion data is potential with inclination property. This paper is aimed to mine the potential inclined intrusion data effectively, and ensure the security of large network. On the basis of the traditional fractional Fourier transform data mining method. An improved potential inclined intrusion accurate data mining algorithm is proposed. New algorithm can separate the time and frequency coupling effectively. The discrete fractional Fourier transform is implemented for the network intrusion data firstly. The data is gathered in the fractional Fourier domain, the inclined intrusion data accumulation is increased. The network signal interference is suppressed effectively. Simulation results show that the proposed data mining algorithm can extract the potential inclined intrusion data in strong concealment. The mining performance is much better than the traditional algorithm, and it can be applied in the network security defense area perfectly.