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In order to avoid interference to primary users within cognitive radio, a multi-frequency RTS/CTS scheme is studied in this paper. Assuming that channels suffer from Rayleigh fading and shadowing, we derive a closed-form of interference avoidance criterion based on multi-frequency RTS/CTS scheme. Simulations are carried out to validate the theoretical formulation. Results show that with the interference...
With the appearance of large-scale database and people's increasing concern about individual privacy, privacy-preserving data mining becomes a hot study area, to which the support vector machine(SVM) belongs. In this paper, a novel privacy-preserving SVM for horizontally partitioned data is given. It has comparable accuracy to that of an ordinary SVM as we obtain the SVM by using the distinct property...
As one of the components in iVCE software platform, iVCE/M devotes to the performance improvement of the I/O-intensive and memory-intensive applications with efficient aggregation of distributed memory resources. To facilitate the deployment of iVCE/M, the data locating algorithm with balanced time and space cost, as well as the transparent interface for the legacy applications without code modification,...
Time series classification based on wavelet transforms and Fourier transform is discussed in this paper. Wavelet transforms have the time-variant characteristic, and are relatively sensitive to the time series with some mutations. Fourier transform is able to reflect various periodic variation of time series clearly. The test proves that the hierarchical clustering based on wavelet transforms can...
A new acquisition scheme is proposed after its basic conception being introduced. The new algorithm is mainly about PN synchronization and symbol synchronization. To realize PN synchronization, a way based on chip-level difference is adopted. For the implementation of symbol synchronization, a new algorithm on basis of post-correlation filtering and peak detecting is presented. It is shown from the...
Aperiodic direct sequence spread spectrum (DSSS) is a special modulation. Owing to its features, some traditional methods for code acquisition cannot be used. Here, we present a highly efficient scheme for the acquisition in aperiodic DSSS system which relies on two steps: the first is the code acquisition using differential detection and the second is timing recovery for data symbol. We also use...
Image denoising is an image processing problem which has a wide use. Total Variation image denoising model is one of the best model at the present time. According to its features, this paper proposes three mathematical programming models which results have the global optimum. The introduction of such model lays the foundation of the further study of mathematical programming models which are relevent...
Wireless technology enables the sensors to gather data to the base station through a so-called multi-hop communication. For data aggregation in wireless sensor networks, a tree overlay is necessary to guide the data transportation from one node to another in an efficient way. Here the data aggregation means that the data is merged while it is transported among the sensors. TinyDB and Cougar are typical...
Aiming at the urgent needs of product's perception design issues, this paper takes mobile phone as the research object and proposes a consumer preference-oriented design method of products' form perception. This paper firstly picks out 11 representative mobile phone pictures by methods of multi-dimensional scaling analysis and cluster analysis. At the same time, 29 image senses words are screened...
The magnetic field distribution of Nb3Sn super-conducting coil is analyzed and obtained when the coil flows the maximum current, the field intensity values of some particular points are given. When the pulse current flows through the super-conducting coil, the large alternate current (AC) loss will appear. Therefore, based on the calculation of the coupling loss time constant for the super-conducting...
Keyword-based search engines often return an unexpected number of results. Zero hits are naturally undesirable, while too many hits are likely to be overwhelming and of low precision. We present an approach for predicting the number of hits for a given set of query terms. Using word frequencies derived from a large corpus, we construct random samples of combinations of these words as search terms...
During the Underground Construction, the ground surface and the building near the construction site would be impacted and the deformation would occur. The empirical deformation forecast methods, as the simple, useful, and more efficient deformation prediction methods, are widely used in Engineering Investigation. We develop the Underground Construction Deformation Display System (UCDDS) basing on...
The PCB production and quality are directly affected by processing data in the design and manufacture file. At present, the existing checkup tools for processing data have some shortages, such as too few objects examined, inconvenience, poor flexibility and scalability, and so on. An automatic checkup method based on knowledge for PCB processing data is presented in this paper, which automatically...
Three methods for the induction motor (IM) applying the interconnection and damping assignment passivity based control (IDA-PBC) have been summarized and compared with each other. After comparison, the IM system controlled by the third IDA-PBC method containing a load torque observer based on adaptation mechanism presents a better performance in accurately tracking the variable rotor speed and being...
Link quality-based routing protocols are often utilized in wireless sensor networks. Link quality estimation algorithms are used to retrieve information about the link quality, which is evaluated to choose the best available path. Concurrently, recent work has revealed severe inaccuracies in link quality estimations provided by modern short-range wireless devices. The sensitivity of routing protocols...
Summary form only given. According to the acoustic theory and the working principle of piezoelectric accelerometers, a vector hydrophone of co-vibrating type is proposed from three-axis piezoelectric accelerometers with vibration-type vector hydrophones. To miniaturize low-frequency vector hydrophones, a kind of three-axis piezoelectric accelerometers with high sensitivity and small sizes was designed,...
Taking the videophone for example, this study developed a process and method of product form perception based on customer preferences. This study proposed the process of product form perception evaluation scale which includes 17 appraisal words and 10 representative pictures by questionnaires, multidimensional scaling, and cluster analysis method. Then it established the relationship model between...
Dual-response surface method is a powerful method for simultaneously optimizing the mean and the variance of responses in quality engineering, in which the minimization of the mean squared error (MSE) is an effective approach. To date, the relative weights of bias and variance have been equally set or determined only by the data. However, the weights should be determined according to the tradeoffs...
A novel system for automatic three-dimensional ink-style rendering is presented. The goal for the whole is to transmit the Chinese painting style to three-dimension models. In this system, the input artwork is first segmented into several regions used for modeling and artistic style analysis: (1) region contours and skeletons is found to build three-dimension models by surface inflation technique,...
In RFID system, a critical issue is security and privacy problem. Firstly, several typical methods to against security and privacy problems are introduced, then based on this protocols, and aim at the shortages in them and other improved ones which provided by some literatures, we propose a new improved scheme based on hash function. The modified scheme resists illegal access, tracking, eavesdropping,...
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