Applied Mechanics and Materials Vols. 599-601

Abstract: Ultra-low frequency difference signal is difficult to detect and process because it is easily mistaken for noise. This paper presents a method based on low-jitter PLL to detect ultra-low frequency signal. A low-jitter PLL circuit has been designed and the performance has been investigated through simulation. The jitter is as low as 10^-12s. The optimized low-jitter PLL can be used for the multiplication of ultra-low frequency difference and improve the measurement accuracy substantially.

Abstract: By using the waveform measurements and the least square method, the duration of transient level, and the duration of transient decreasing segment of aircraft DC transient signal are evaluated precisely. The evaluation courses and some technical problems are discussed in detail, the uncertainty analysis both of the durations are presented. Some test results have proved the effectiveness and practicability of the method. It could be applied to the characteristic and performance evaluation of aircraft DC transient signal waveform generators.

Abstract: Currently, many universities have set up their own system for providing employment information service, problems that following the independently operating and maintaining modes are: on the one hand, employers have to register a number of university employment information system to obtain information on a number of graduates; on the other hand, graduates also need to browse a number of university employment information site to get more information on business recruitment, which severely reduces the transparency and efficiency of information data queries. To solve the above problems, this paper propose the university employment information integration model on the basis of distributed storage and computing technology, which realizes the integration of multiple heterogeneous employment information database.

Abstract: Magnetic anomaly detection is a passive method for detection of a ferromagnetic target, and its performance is often limited by external noise with a power spectral density of 1/f ^a, (0<a<2). In consideration of this kind of noise is non-stationary, self-similarity and long-range correlation, an effective adaptive detection based on the wavelet transform is proposed in this paper. The discrete wavelet transform of the noisy signal is chosen as the inputs of the adaptive whitening filter, and then decomposed by the orthonormal basis functions (OBFs) and the energy signal was taken out for threshold detection. The simulation results show that the algorithm improves the effect for detecting weak magnetic anomaly signal contaminated by 1/f ^a noise.

Abstract: Xiao and Li proposed protocol XKAS and claimed it to be an efficient and secure two-party authenticated Diffie-Hellman key agreement protocol. In this letter, we show that the protocol is vulne- rable to a key-compromise impersonation attack. We also proposed XKAS+, which can withstand such attacks. The new protocol enjoys this property at the expense of a slight increase in computational workload with respect to the original version.

Abstract: this paper mainly introduces a wideband SPDT switch with TTL control. Firstly, everypossible configuration is contrasted, the theories of basic GaAs switch configurations arementioned. Secondly, the theories of basic GaAs switch configurations are mentioned.Subsequently, appropriate topology is selected for this SPDT switch. This switch has been realizedby 0.5µm GaAs pHEMT process. this switch exhibits high performance: over DC~4GHz, insertionloss is lower than 1dB; The isolation is lower than 50dB; the ripple variation of insertion loss is lessthan ±0.15dB; input return loss is lower than 14dB; on state, output return loss is lower than 16dB;off state, over 0.2GHz-4GHz, output return loss is lower than 12dB; on and off time are less than55ns. The layout of the switch with a chip size is 0.81 mm×1.22mm.

Abstract: Feature extraction is a key point of text categorization[1]. The accuracy of extraction will directly affect the accuracy of text classification. This paper introduces and compares 4 commonly used methods of text feature extraction: IG (Information gain), MI (Mutual information), CHI (statistics), DF (Document frequency), and proposes an improved method based on the method of CHI. Experiment result shows that the proposed method can improve the accuracy of text categorization.

Abstract: The objective of this paper is to build a system for pedestrian detection in an outdoor environment. The contribution of this paper is the detection method that integrates the silhouette edge information with patterns of motion in each frame of the image sequence. The test results show that the high-precision, good adaptability, and real-time performance of the proposed method.

Abstract: Although turbo equalization has superior performance, the data processing delay produced by large iterations has become its major drawback for real-time situations. Based on the MMSE criterion, the normal-probability-plot (NPP) of linear equalizer’s extrinsic information is studied in this paper, with the conclusion of the extrinsic information’s approximate Gaussian distribution obtained. In various conditions, the iterative number can be controlled dynamically based on the extrinsic information statistics. The simulation results approves that the technique is able to make delay dwindle largely with small performance degradation.

Abstract: Big data is very useful for the computer science research. Nowadays smart phones are popular, and many of which are locked with nine pattern; it is very convenient to use, just draw what you can open the phone, rather than input a password. In this article, the unlock crack of smart phone is introduced, and the combined nine points crack is presented of different patterns, the research draw the conclusion that it is much more complex enough security for this unlock crack than we think.