Abstract: Frames have become the focus of active research, both in theory and in applications. In the article, the notion of bivariate minimum-energy wavelet frames is introduced. A precise existence criterion for minimum-energy frames in terms of an inequality condition on the Laurent polynomial symbols of the filter functions is provided. An explicit formula for designing minimum-energy frames is also establish- ed. The sufficient condition for the existence of a class of affine pseudoframes with filter banks is obtained by virtue of a generalized multiresolution analysis. The pyramid decomposition scheme is established based on such a generalized multiresol- -ution structure.
Abstract: In this article, the notion of orthogonal nonseparable four-dimensional wavelet packs, which is the generalization of orthogonal univariate wavelet packs, is introduced. A new approach for constructing them is presented by iteration method and wavelets as well wavelet frames. The biorthogonality properties of four-dimensi- -onal wavelet packets are discussed. Three biorthogonality formulas concerning these wavelet packs are estabished. A necessary and sufficient condition for the existence of the pyramid decomposition scheme of space is presented.
Abstract: Ontology is adopted as a standard for knowledge representation on the Semantic Web, and Resource Description Framework (RDF) is used to add structure and meaning to Web applications. In order to incorporate fuzzy systems into the Semantic Web, this paper utilizes fuzzy ontology to represent formally the fuzzy linguistic variables, considering the semantic relationships between fuzzy concepts. Then fuzzy rule is described as a RDF resource with properties: “IF” and “THEN”, and rule's antecedent and consequent is represented in RDF statement. Taking the fuzzy control system of industrial washing machine for example, the fuzzy system with ontology and RDF is built, which shows that this research enables distributed fuzzy applications on the Semantic Web.
Abstract: In view of the problems of limited energy of the nodes and threat to routing security in wireless sensor networks, Energy-efficient Secure Routing Protocol (ESRP), an energy-efficient secure routing protocol for wireless sensor networks, is proposed. According to the structured topology of hexagonal mesh, hops at different directions are calculated on the optimal route for transmitting data packets in ESRP. With the help of characters of hops, the nodes can rapidly find a route among multiple optimal routes by the policy of the twice probability routing selection. Data breach is prevented by data encryption and data security is realized by one-way hash key chain and symmetric key authentication. Analysis and simulation results show that ESRP has better performance on security and saving energy.
Abstract: When magnetic fields with the magnetic induction intensity of 0.4T, 0.8T, 1.2T, 1.6T and 2.0T are used to deal with germinating cabbage seeds for 5min, 10min, 15min and 20min separately, the results show that the appropriate combination of field strength and time can activate peroxidase (POD) and polyphenol oxidase(PPO) apparently, and decrease the content of MDA at the same time. Through the downy mildew inoculation tests, the magnetic field effects on the induced-resistance of Chinese cabbage are significantly lower than control, indicating that magnetic field treatment improve the Chinese cabbage downy mildew resistance by removing free radicals in plants, increasing the metabolism of plant’s secondary phenols and reduce the plant tissue within the cytoplasm of the cell membrane permeability and so on.
Abstract: Due to the node failures incurred by intrusion threat, a wireless sensor networks will initiate topology re-generation, which is based on correct availability evaluation of current intrusion-tolerant topology. The paper proposes an availability evaluation model based on semi-Markov process (SMP) to estimate topology availability of the intrusion-tolerant topology concerning the effects from intrusion behaviors. In view of some limitations of node computation ability and storage ability, this model reduces the complexities resulting from modeling the different intrusion threats and is set up on the uniform intruding results to simplify the model design. Using the DTMC model embedded in SMP topology availability is computed and finally we analyze the sensitivity to parameters in the model.
Abstract: To study the dynamic wheel load on the road, a dynamic multi-axle vehicle mode has been developed, which is based on distribute loading weight and treats tire stiffness as the function of tire pressure and wheel load. Taking a tractor-semitrailer as representative, the influence factors and the influence law of the dynamic load were studied. It is found that the load coefficient increases with the increase of road roughness, vehicle speed and tire pressure, yet it decreases with the increase of axle load. Combining the influences of road roughness, vehicle speed, axle load and tire pressure, the dynamic load coefficient is 1.14 for the level A road, 1.19 for the level B road, 1.27 for the level C road, and 1.36 for the level D road.
Abstract: The characteristic of not easy to be destroyed makes HF communication be widely used in emergency or special circumstance as earthquake relief, military communication and etc. Traditional routing protocols commonly use least hop number as routing selection criteria. In the HF communication network, for its special channel characteristics, in case of poor link quality, the transmission performance of routing whose hop number is less may be poorer than that have more hops. Taking routing quality as selection criteria has become the best choice. Based on analysis on routing quality calculation method of the third-generation HF communication system, the paper brought out a kind of optimal routing selection algorithm of HF Ad Hoc network based on link quality.
Abstract: Application Layer Multicast (ALM) is more flexible than that in IP layer and easy to optimize for specific applications, so the research on it has become a hotspot. Aiming at the problem of most ALM protocol ignoring bandwidth of covering tree, the paper presented a new heuristic algorithm Max-Delta, which inferred the underlying link topology using end-to-end measurement technology. On the basis of this, a kind of Fast Application layer Tree (FAT) algorithm to construct covering tree was proposed to meet the requirements of bandwidth. In addition, the algorithm's time complexity was also analyzed. Simulation results show that Max-Delta algorithm can obtain network topology accurately with less network measurement times comparing with random measurement algorithm and longest path measurement algorithm.