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91.
This work proposes a method to decompose the kernel within-class eigenspace into two subspaces: a reliable subspace spanned
mainly by the facial variation and an unreliable subspace due to limited number of training samples. A weighting function
is proposed to circumvent undue scaling of eigenvectors corresponding to the unreliable small and zero eigenvalues. Eigenfeatures
are then extracted by the discriminant evaluation in the whole kernel space. These efforts facilitate a discriminative and
stable low-dimensional feature representation of the face image. Experimental results on FERET, ORL and GT databases show
that our approach consistently outperforms other kernel based face recognition methods.
相似文献
Alex KotEmail: |
92.
Alex K. Goins Ryan Carpenter Weng-Keen Wong Ravi Balasubramanian 《Autonomous Robots》2016,40(4):687-699
With the goal of advancing the state of automatic robotic grasping, we present a novel approach that combines machine learning techniques and physical validation on a robotic platform to develop a comprehensive grasp predictor. After collecting a large grasp sample set (522 grasps), we first conduct a statistical analysis of the predictive ability of grasp quality metrics that are commonly used in the robotics literature. We then apply principal component analysis and Gaussian process (GP) algorithms on the grasp metrics that are discriminative to build a classifier, validate its performance, and compare the results to existing grasp planners. The key findings are as follows: (i) several of the existing grasp metrics are weak predictors of grasp quality when implemented on a robotic platform; (ii) the GP-based classifier significantly improves grasp prediction by combining multiple grasp metrics to increase true positive classification at low false positive rates; (iii) The GP classifier can be used generate new grasps to improve bad grasp samples by performing a local search to find neighboring grasps which have improved contact points and higher success rate. 相似文献
93.
An action is a pair of sets, C and S, and a function \(f:C\times S \rightarrow C\). Rothschild and Yalcin gave a simple axiomatic characterization of those actions arising from set intersection, i.e. for which the elements of C and S can be identified with sets in such a way that elements of S act on elements of C by intersection. We introduce and axiomatically characterize two natural classes of actions which arise from set intersection and union. In the first class, the \(\uparrow \!\!\downarrow \)-actions, each element of S is identified with a pair of sets \((s^\downarrow ,s^\uparrow )\), which act on a set c by intersection with \(s^\downarrow \) and union with \(s^\uparrow \). In the second class, the \(\uparrow \!\!\downarrow \)-biactions, each element of S is labeled as an intersection or a union, and acts accordingly on C. We give intuitive examples of these actions, one involving conversations and another a university’s changing student body. The examples give some motivation for considering these actions, and also help give intuitive readings of the axioms. The class of \(\uparrow \!\!\downarrow \)-actions is closely related to a class of single-sorted algebras, which was previously treated by Margolis et al., albeit in another guise (hyperplane arrangements), and we note this connection. Along the way, we make some useful, though very general, observations about axiomatization and representation problems for classes of algebras. 相似文献
94.
A simple mutual exclusion algorithm is presented that only uses nonatomic shared variables of bounded size, and that satisfies
bounded overtaking. When the shared variables behave atomically, it has the first-come-first-served property (FCFS). Nonatomic
access makes information vulnerable. The effects of this can be mitigated by minimizing the information and by spreading it
over more variables. The design approach adopted here begins with such mitigating efforts. These resulted in an algorithm
with a proof of correctness, first for atomic variables. This proof is then used as a blueprint for the simultaneous development
of the algorithm for nonatomic variables and its proof. Mutual exclusion is proved by means of invariants. Bounded overtaking
and liveness under weak fairness are proved with invariants and variant functions. Liveness under weak fairness is formalized
and proved in a set-theoretic version of temporal logic. All these assertions are verified with the proof assistant PVS. We
heavily rely on the possibility offered by a proof assistant like PVS to reuse proofs developed for one context in a different
context. 相似文献
95.
Invariant ellipsoid method for minimization of unmatched disturbances effects in sliding mode control 总被引:1,自引:0,他引:1
A new sliding mode control design algorithm for a linear and a class of nonlinear quasi-Lipschitz disturbed system is presented. It is based on the appropriate selection of the sliding surface via invariant ellipsoid method. The designed control guarantees minimization of unmatched disturbances effects to system motions in a sliding mode. The obtained theoretical results are approved by numerical simulations. 相似文献
96.
Users expect applications to successfully cope with the expansion of information as necessitated by the continuous inclusion of novel types of content. Given that such content may originate from ‘not‐seen thus far’ data collections and/or data sources, the challenging issue is to achieve the return of investment on existing services, adapting to new information without changing existing business‐logic implementation. To address this need, we introduce DOLAR (Data Object Language And Runtime), a service‐neutral framework which virtualizes the information space to avoid invasive, time‐consuming, and expensive source‐code extensions that frequently break applications. Specifically, DOLAR automates the introduction of new business‐logic objects in terms of the proposed virtual ‘content objects’. Such user‐specified virtual objects align to storage artifacts and help realize uniform ‘store‐to‐user’ data flows atop heterogeneous sources, while offering the reverse ‘user‐to‐store’ flows with identical effectiveness and ease of use. In addition, the suggested virtual object composition schemes help decouple business logic from any content origin, storage and/or structural details, allowing applications to support novel types of items without modifying their service provisions. We expect that content‐rich applications will benefit from our approach and demonstrate how DOLAR has assisted in the cost‐effective development and gradual expansion of a production‐quality digital library. Experimentation shows that our approach imposes minimal overheads and DOLAR‐based applications scale as well as any underlying datastore(s). Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
97.
Long-lived renaming allows processes to repeatedly get distinct names from a small name space and release these names. This
paper presents two long-lived renaming algorithms in which the name a process gets is bounded above by the number of processes
currently occupying a name or performing one of these operations. The first algorithm is asynchronous, uses LL/SC objects, and has step complexity that is linear in the number of processes, c, currently getting or releasing a name. The second is synchronous, uses registers and counters, and has step complexity that
is polylogarithmic in c. Both tolerate any number of process crashes. 相似文献
98.
The magic of computer graphics as seen in many current movies and computer games comes at a cost. Creating the geometric forms with which to generate synthetic characters and animating the characters to bring them to life require either highly skilled artists and/or sophisticated capture devices. Both are expensive and, in the case of highly skilled artists, rare. 相似文献
99.
Ben-Akiva Moshe Bierlaire Michel Burton Didier Koutsopoulos Haris N. Mishalani Rabi 《Networks and Spatial Economics》2001,1(3-4):293-318
Advanced Traveler Information Systems (ATIS) and Advanced Traffic Management Systems (ATMS) have the potential to contribute to the solution of the traffic congestion problem. DynaMIT is a real-time system that can be used to generate guidance for travelers. The main principle on which DynaMIT is based is that information should be consistent, and user optimal. Consistency implies that the traffic conditions experienced by the travelers are consistent with the condition assumed in generating the guidance. To generate consistent user optimal information, DynaMIT performs two main functions: state estimation and prediction. A demand simulator and a supply simulator interact to perform these tasks. A case study demonstrates the value of the system. 相似文献
100.
Fukunaga AS 《Evolutionary computation》2008,16(1):31-61
The development of successful metaheuristic algorithms such as local search for a difficult problem such as satisfiability testing (SAT) is a challenging task. We investigate an evolutionary approach to automating the discovery of new local search heuristics for SAT. We show that several well-known SAT local search algorithms such as Walksat and Novelty are composite heuristics that are derived from novel combinations of a set of building blocks. Based on this observation, we developed CLASS, a genetic programming system that uses a simple composition operator to automatically discover SAT local search heuristics. New heuristics discovered by CLASS are shown to be competitive with the best Walksat variants, including Novelty+. Evolutionary algorithms have previously been applied to directly evolve a solution for a particular SAT instance. We show that the heuristics discovered by CLASS are also competitive with these previous, direct evolutionary approaches for SAT. We also analyze the local search behavior of the learned heuristics using the depth, mobility, and coverage metrics proposed by Schuurmans and Southey. 相似文献