1000 resultados para Fujian Sheng


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We attempt to generate new solutions for the moisture content form of the one-dimensional Richards' [1931] equation using the Lisle [1992] equivalence mapping. This mapping is used as no more general set of transformations exists for mapping the one-dimensional Richards' equation into itself. Starting from a given solution, the mapping has the potential to generate an infinite number of new solutions for a series of nonlinear diffusivity and hydraulic conductivity functions. We first seek new analytical solutions satisfying Richards' equation subject to a constant flux surface boundary condition for a semi-infinite dry soil, starting with the Burgers model. The first iteration produces an existing solution, while subsequent iterations are shown to endlessly reproduce this same solution. Next, we briefly consider the problem of redistribution in a finite-length soil. In this case, Lisle's equivalence mapping is generalized to account for arbitrary initial conditions. As was the case for infiltration, however, it is found that new analytical solutions are not generated using the equivalence mapping, although existing solutions are recovered.

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To use the vast amount of information efficiently and effectively from Web sites is very important for making informed decisions. There are, however, still many problems that need to be overcome in the information gathering research arena to enable the delivery of relevant information required by users. In this paper, an information gathering system is develop by means of multiple agents to solve those problems. We employed some ideas of Gaia's methodology and an open agent architecture to analyze and design the system. The system consists of a query preprocessing agent, information retrieval agent, information filtering agent, and information management agent. The filtering agent is trained with categorized documents and can provide users with the necessary information. The experimental results show that all agents in the system can work cooperatively to retrieve relevant information from the World Wide Web environment.

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In this paper, we propose a model for discovering frequent sequential patterns, phrases, which can be used as profile descriptors of documents. It is indubitable that we can obtain numerous phrases using data mining algorithms. However, it is difficult to use these phrases effectively for answering what users want. Therefore, we present a pattern taxonomy extraction model which performs the task of extracting descriptive frequent sequential patterns by pruning the meaningless ones. The model then is extended and tested by applying it to the information filtering system. The results of the experiment show that pattern-based methods outperform the keyword-based methods. The results also indicate that removal of meaningless patterns not only reduces the cost of computation but also improves the effectiveness of the system.

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Two types of pyrite framboids (PF, probably sulphate-reducing bacteria) have been found
within the Zoophycos spreiten, hosted in the Guadalupian (Middle Permian) glaciomarine greywacke
of the Westley Park Sandstone Member within the Broughton Formation from the southern Sydney
Basin of southeastern Australia. They are composed of non-sheathed (PF1) and sheathed (PF2)
sub-micron balls, respectively. Chemically, the sub-micron balls consist of iron, sulphur, carbon and
oxygen. Both PF1 and PF2 occur in rhythmic alternationwithin the thick, light-grey and thin, dark-grey
minor lamellae of Zoophycos spreiten. The framboids from the minor lamellae are highly abundant and
occur in an orderly arrangement of equal density and in a good state of preservation.Within Zoophycos
spreiten no homogeneous filling, fecal pellets, or any sign of re-exploitation of the minor lamellae have
been recognized. No similar framboids have been observed outside Zoophycos spreiten. Therefore, the
framboids are interpreted as the pyritized remains of microbial colonies within Zoophycos spreiten.
The trace Zoophycos would be a multifunctional garden thatmay have been carefully constructed by the
Zoophycos maker, where different microbial colonies were orderly and carefully planted and cultured
within different minor lamellae. Further, it is proposed that the Zoophycos maker had a symbiotic
relationship with microbial colonies on the mutual basis of food supply and redox conditions. The fact
that the overlying spreiten cut the underlying ones indicates that the Zoophycos from the study area is
of an upward construction. The rhythmic alternation of both the thick, light-grey and thin, dark-grey
minor lamellae within Zoophycos spreiten may be suggestive of a gardening manner of the Zoophycos
maker responding to the warm and cold changes, food supply in pulses and variations of sedimentation
rate for planting and culturing microbial colonies under the conditions of a glaciomarine environment
at the high latitudes.

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The systematics, palaeoecology, palaeobiogeography and patterns of faunal change of Permian brachiopods from Sichuan, China and Pahang, Malaysia were investigated. The brachiopods from Pahang were systematically described for the first time. Five new species and one new genus were found in Sichuan, and two extinction and five origination events were recognised.

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Parametric modelling is gaining in popularity as both a fabrication and design tool, but its application in the architectural design industry has not been widely explored. Parametric modelling has the ability to generate complex forms with intuitively reactive components, allowing designers to express and fabricate structures previously too laborious and geometrically complex to realise. This alIows designers to address a project at both the macro and micro levels of resolution in the governing control surface and the individual repetitive component. This two level modelling control, of component and overall surface, can allow designers to explore new types of form generation subject to parametric constraints. Shading screens have been selected as the focus for this paper and are used as a medium to explore form generation within a given set of functional parameters. Screens can have many applications in a building but for the purpose of the following case studies, lighting quality and passive sun control are the main functional requirement. A set of screen components have been designed within certain shading parameters to create a generic component that can automatically adapt to any given climatic conditions. These will then be applied to surfaces of varying degrees of geometric complexity to be analysed in their ability to correctly tessellate and create a unified screening array true to the lighting requirements placed on the generic component.

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This paper reports on three approaches to the translation of Gaussian surface models into scaled physical prototype models. Using the geometry of Eladio Dieste's Gaussian Vaults, the paper reports on the aspects encountered in the process of digital to physical prototype fabrication. The primary focus of the paper is on exploring the design geometry, investigating methods for preparing the geometry for fabrication and constructing physical prototypes. Three different approaches in the translation from digital to physical models are investigated: rapid prototyping, two dimensional surface models in paper and structural component models using Computer Numerical Controlled (CNC) fabrication. The three approaches identify a body of knowledge in the design and prototyping of Gaussian vaults. Finally the paper discusses the digital to. fabrication translation processes with regards to the characteristics, benefits and limitations of the three approaches of prototyping the ruled surface geometry of Gaussian Vaults.

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With the granting of the franchise to white men and women in 1902, Australia became one of the first mass electoral democracies. When the early federal governments passed innovative social and economic legislation, Australia also laid claim to being, or at least becoming, a social democracy. Nonetheless, these achievements built upon an earlier record of political, social, and economic reform in the Australian colonies. This paper offers a brief history of the evolution of Australian democracy that takes account of the interactions between institutional change and political struggles for citizenship rights. The process of democratisation has not been uniform, either in its evolution or scope, and the outcomes for citizens have been uneven. Where liberal and social democratic principles generally predominate, these remain in constant tension with more authoritarian tendencies, which then become a focus for resistance from individual citizens, organised labour, and social movements. Democratisation in Australia, as in many countries, is a process that inevitably involves conflict, not only over the character of its political and legal institutions, but also over who is to be included or excluded as citizens, and the rights and responsibilities of citizenship.

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From the constitutional point of view, all ideology in a pluralistic society structures have their own status and function. The rise of China needs a healthy, diverse and balanced thinking the situation. We need a capacity of macro-narrative and a framework to develop a macro perspective, the various ideologies put this macro, the constitutional system integration. This article is about ideology than an example, the analysis and comparison of three models. The first mode is now at in the formation and development process, and our political system to adapt to the "balanced" mode. The second model is adopted, representing the "left" "right" interest groups to reach beyond the ruling party turns around, balance of interests purpose. The third is in the process of policy formulation and selection of multi-party consultation and inclusive pattern of results of various think tanks.

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In this paper, we present some practical experience on implementing an alert fusion mechanism from our project. After investigation on most of the existing alert fusion systems, we found the current body of work alternatively weighed down in the mire of insecure design or rarely deployed because of their complexity. As confirmed by our experimental analysis, unsuitable mechanisms could easily be submerged by an abundance of useless alerts. Even with the use of methods that achieve a high fusion rate and low false positives, attack is also possible. To find the solution, we carried out analysis on a series of alerts generated by well-known datasets as well as realistic alerts from the Australian Honey-Pot. One important finding is that one alert has more than an 85% chance of being fused in the following 5 alerts. Of particular importance is our design of a novel lightweight Cache-based Alert Fusion Scheme, called CAFS. CAFS has the capacity to not only reduce the quantity of useless alerts generated by IDS (Intrusion Detection System), but also enhance the accuracy of alerts, therefore greatly reducing the cost of fusion processing. We also present reasonable and practical specifications for the target-oriented fusion policy that provides a quality guarantee on alert fusion, and as a result seamlessly satisfies the process of successive correlation. Our experimental results showed that the CAFS easily attained the desired level of survivable, inescapable alert fusion design. Furthermore, as a lightweight scheme, CAFS can easily be deployed and excel in a large amount of alert fusions, which go towards improving the usability of system resources. To the best of our knowledge, our work is a novel exploration in addressing these problems from a survivable, inescapable and deployable point of view.

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Distributed denial of service (DDoS) attack is a continuous critical threat to the Internet. Derived from the low layers, new application-layer-based DDoS attacks utilizing legitimate HTTP requests to overwhelm victim resources are more undetectable. The case may be more serious when suchattacks mimic or occur during the flash crowd event of a popular Website. In this paper, we present the design and implementation of CALD, an architectural extension to protect Web servers against various DDoS attacks that masquerade as flash crowds. CALD provides real-time detection using mess tests but is different from other systems that use resembling methods. First, CALD uses a front-end sensor to monitor thetraffic that may contain various DDoS attacks or flash crowds. Intense pulse in the traffic means possible existence of anomalies because this is the basic property of DDoS attacks and flash crowds. Once abnormal traffic is identified, the sensor sends ATTENTION signal to activate the attack detection module. Second, CALD dynamically records the average frequency of each source IP and check the total mess extent. Theoretically, the mess extent of DDoS attacks is larger than the one of flash crowds. Thus, with some parameters from the attack detection module, the filter is capable of letting the legitimate requests through but the attack traffic stopped. Third, CALD may divide the security modules away from the Web servers. As a result, it keeps maximum performance on the kernel web services, regardless of the harassment from DDoS. In the experiments, the records from www.sina.com and www.taobao.com have proved the value of CALD.