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81.
Based on a polynomial operator approach, a new sparse controller structure is derived, which is actually an improved version of the recently proposed structure [Li, G. (2004). A polynomial-operator-based DFIIt structure for IIR filters. IEEE Transactions on Circuits and Systems II, 51, 147-151]. The performance of the proposed structure is analyzed by deriving the corresponding expression of roundoff noise gain and the problem of finding optimized sparse structures is solved efficiently with a genetic algorithm (GA). A numerical example is given, which shows that the newly developed structure can achieve much better performance than some well-known structures and particularly outperforms the traditional optimal fully parametrized realization greatly in terms of reducing roundoff noise and implementation complexity. 相似文献
82.
83.
Douglas Walton 《Artificial Intelligence and Law》2006,14(3):177-239
In this paper it is shown how tools developed in argumentation theory and artificial intelligence can be applied to the development
of a new dialectical analysis of the speech act of making a proposal in a deliberation dialogue. These tools are developed,
modified and used to formulate dialogue pre-conditions, defining conditions and post-conditions for the speech act of making
a proposal in a deliberation dialogue. The defining conditions set out what is required for a move in a dialogue to count
as the making of a proposal by one of the parties. What is required are the conditions that (1) the move fit the requirements
of the argumentation scheme for practical reasoning, and (2) the premises are propositions describing common goals of both
parties or propositions that they reasonably consider means to achieve these goals. The analysis goes beyond the standard
speech act approach by specifying not only the normative requirements for making a well-formed proposal, but also the requirements
for responding to it by questioning or criticizing it, and the requirements for defending it. 相似文献
84.
85.
Details of the vorticity field structure associated with the 3D Tollmien-Schlichting waves have been examined based upon the
recent numerical studies of the subject. First, a single obliquet-s wave has been found to have the velocity component parallel to the wave front playing an overall dominant role, in particular,
to create the longitudinal vorticity. The so-called Benney-Lin longitudinal vortices are then demonstrated to be, in fact,
a minor consequence compared with the localized longitudinal vorticity field and its periodic pumping. Finally, the formation
of the longitudinal vorticity field in the fundamental- and subharmonic-mode interactions is explained.
The research reported in this paper has been supported in part by Bundesministerium für Forschung und Technologie and by Deutsche
Forschungsgemeinschaft. The major part of the paper has been presented at the Third Asian Congress of Fluid Mechanics, 1–5
September 1986, in Tokyo, as a General Lecture by the senior author, FRH. 相似文献
86.
87.
Mining frequent itemsets has emerged as a fundamental problem in data mining and plays an essential role in many important data mining tasks.In this paper,we propose a novel vertical data representation called N-list,which originates from an FP-tree-like coding prefix tree called PPC-tree that stores crucial information about frequent itemsets.Based on the N-list data structure,we develop an efficient mining algorithm,PrePost,for mining all frequent itemsets.Efficiency of PrePost is achieved by the following three reasons.First,N-list is compact since transactions with common prefixes share the same nodes of the PPC-tree.Second,the counting of itemsets’ supports is transformed into the intersection of N-lists and the complexity of intersecting two N-lists can be reduced to O(m + n) by an efficient strategy,where m and n are the cardinalities of the two N-lists respectively.Third,PrePost can directly find frequent itemsets without generating candidate itemsets in some cases by making use of the single path property of N-list.We have experimentally evaluated PrePost against four state-of-the-art algorithms for mining frequent itemsets on a variety of real and synthetic datasets.The experimental results show that the PrePost algorithm is the fastest in most cases.Even though the algorithm consumes more memory when the datasets are sparse,it is still the fastest one. 相似文献
88.
简单介绍了带隙基准源的基本原理,给出了一款基于Widlar结构的带曲率补偿的带隙基准电压电流源的设计方法,通过采用TSMC0.5μm工艺库对电路进行仿真,在-40~150℃的温度范围内,其带隙基准的输出具有12ppm/℃的温度系数,电流基准的输出具有42ppm/℃。此外,文中还对曲率补偿电路的工作原理进行了分析,并且通过仿真波形对曲率补偿的工作机制进行了讨论。 相似文献
89.
软件服务外包作为一个新型的软件产业方兴未艾,这种贸易方式加强了国际间的合作与区域性产业的互补。作为中国的近邻日本,这种互补方式的优势显得尤为突出。但是,由于中国外包企业的竞争力较弱、技术力量不够雄厚、企业规模尚未形成等弱点存在,大大制约着中国软件服务外包业的进一步发展。特别是随着诸多新兴接包国家和地区的崛起,使得中国所面临的竞争进一步加大,从前的低成本优势将得到削弱。这些都严重地制约着中国软件服务外包行业的健康发展。有序地调整以低端为主的产业结构,提高自主创新能力,加大服务外包在国家IT(Information Technology)产业中的比重,从而增强核心竞争力。 相似文献
90.