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641.
Bernard BERCU 《系统科学与复杂性》2007,20(2):243-250
A wide range of literature concerning classical asymptotic properties for linear models with adaptive control is available, such as strong laws of large numbers or central limit theorems. Unfortunately, in contrast with the situation without control, it appears to be impossible to find sharp asymptotic or nonasymptotic properties such as large deviation principles or exponential inequalities. Our purpose is to provide a first step towards that direction by proving a very simple exponential inequality for the standard least squares estimator of the unknown parameter of Gaussian autoregressive process in adaptive tracking. 相似文献
642.
643.
SU Yong ZHOU Jingli YU Shengsheng JIANG Minghua LIU Gang 《武汉大学学报:自然科学英文版》2007,12(2):249-254
This paper introduces agent-based methodology to build a distributed autonomic storage system infrastructure, and an effectively negotiation mechanism based on agent is applied for data location. We present Availability-based Data Allocation (ADA) algorithm as a data placement strategy to achieve high efficient utilization of storage resources by employing multiple distributed storage resources. We use Bloom filter in each storage device to track the location of data. We present the data lookup strategy that small size of read request is handled directly, and large size of read request is handled by cooperation with storage devices.The performance evaluation shows that the data location mechanism is high available and can work well for heterogeneous autonomic storage systems. 相似文献
644.
LI Weifeng DU Jinyuan 《武汉大学学报:自然科学英文版》2007,12(6):985-991
We discuss the linear conjugate boundary value problems on the unit circle and the real axis. We obtain some Fredholm integral equations. Using thess equations we discuss the solvable conditions on these problems and we also give a direct method for the extension problems on the real axis. 相似文献
645.
Doug Walton 《Systemic Practice and Action Research》2007,20(5):369-386
Public discourse in Western democracies, particularly in the United States, is far from the Habermasian ideal of citizens
engaging in a rational discussion of public affairs. Rather than providing an arena for informed deliberation, the growing
expertise of the media, lobbyists, and politicians has sub-optimized the current system of discourse to focus on emotional
manipulation and the creation of polarized interests, each competing with each other for dominance. Avoiding a potentially
disastrous outcome from this unbalancing of public discourse requires a revitalization of the public sphere and a return of
the citizen voice in public decision making. To that end, systems thinkers have a tremendous opportunity and can play an important
role. This article will explore the current challenges facing public discourse and outline that potential role. 相似文献
646.
XIA Yingqing TIAN Huamei DUAN Zhiguo WU Ling XU Penggen 《武汉大学学报:自然科学英文版》2007,12(3):481-484
This paper presents a method to analyze and calculate the angular glint of targets. By parting the target to very small size cells, using high-frequency approximation, the near-field radar cross section (RCS) is calculated based on the scattering from complex targets and environments (SCTE) system, and the angular glint is calculated by the phase grads. The results show that the angular glint can be calculated exactly in the SCTE system, and this method is correct and efficient. In the near-zone, the far-field theory is not applicable and the angular glint should be calculated by the near-field theory. 相似文献
647.
TAN Zuowen 《武汉大学学报:自然科学英文版》2008,13(6):680-684
A group-oriented (t, n) threshold signature scheme employs the cryptographic techniques of secret share, allows any subset of t players out of n players to sign message on behalf of the group and disallows the creation of a valid signature if fewer than t players take part in the signature protocol. In this paper, we proposed a new group-oriented (t, n) threshold signature schemes with traceable signers based on Schnorr signature. The proposed scheme is proved traceable, robust and unforgeable against the "static" adversary with the discrete logarithm assumption in the random oracle model and existence of broadcast channel. The proofs of the strongest security (existential unforgeability against adaptively chosen message attacks under the discrete logarithm assumption) are provided in the random oracle model. 相似文献
648.
Traditional approach of design by contract, due to mixing the contract code with application code, is difficult for the extensibility
and reusability of software system. This paper presents a framework named JADBC for design by contract based on Aspect-Oriented
Programming (AOP) to resolve these problems. By providing a new modularized element, aspect, the framework successfully separates
the contracts in design by contract, from functional codes. The implementation of this framework is based on dynamic AOP which
can have the contract changed at runtime, consequently, enhancing program flexibility. JADBC framework modularizes the contracts
in a clear-cut fashion that is easier to design, implement, and maintain.
Biography: WEN Jing (1982–), female, Ph.D. candidate, research directions: software engineer, aspect-oriented software development. 相似文献
649.
CHEN Lihua 《武汉大学学报:自然科学英文版》2008,13(1):9-13
The singularly perturbed initial boundary value problems for the reaction diffusion system are raised. Firstly, under suitable conditions, using a iteration technique, the differential inequalities theorem is constructed and introducing two auxiliary functions the existence and uniqueness theorem of solution for the basic reaction diffusion system is proved. Using the singularly perturbed method the formal asymptotic expressions of the solution are constructed with power series theory. By using the comparison theorem the existence and its asymptotic behavior of solution for the original problem are studied. Finally, using method of estimate inequalities, the structure of solutions for the problem is discussed thoroughly in three cases and asymptotic solution of the original problem is given. The asymptotic behavior of solution in the three cases is proved. 相似文献
650.
OPTIMAL MAINTENANCE AND REPLACEMENT OF EXTRACTION MACHINERY 总被引:1,自引:1,他引:0
This paper considers a problem of optimal preventive maintenance and replacement schedule of equipment devoted to extracting resources from known deposits. Typical examples are oil drills, mine shovels, etc. At most one replacement of the existing machinery by a new one is allowed. The problem is formulated as an optimal control problem subject to the state constraint that the remaining deposit at any given time is nonnegative. We show that the optimal preventive maintenance, production rates, and the replacement and salvage times of the existing machinery and the new one, if required, can be obtained by solving sequentially a series of free-end-point optimal control problems. Moreover, an algorithm based on this result is developed and used to solve two illustrative examples. 相似文献