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1.
The radial basis function (RBF) centers play different roles in determining the classification capa- bility of a Gaussian radial basis function neural network (GRBFNN) and should hold different width values. However, it is very hard and time-consuming to optimize the centers and widths at the same time. In this paper, we introduce a new insight into this problem. We explore the impact of the definition of widths on the selection of the centers, propose an optimization algorithm of the RBF widths in order to select proper centers from the center candidate pool, and improve the classification performance of the GRBFNN. The design of the objective function of the optimization algorithm is based on the local mapping capability of each Gaussian RBF. Further, in the design of the objective function, we also handle the imbalanced problem which may occur even when different local regions have the same number of examples. Finally, the recursive orthogonal least square (ROLS) and genetic algorithm (GA), which are usually adopted to optimize the RBF centers, are separately used to select the centers from the center candidates with the initialized widths, in order to testify the validity of our proposed width initialization strategy on the selection of centers. Our experimental results show that, compared with the heuristic width setting method, the width optimization strategy makes the selected cen- ters more appropriate, and improves the classification performance of the GRBFNN. Moreover, the GRBFNN constructed by our method can attain better classification performance than the RBF LS-SVM, which is a state-of-the-art classifier.  相似文献   

2.
In this paper,we report a novel optimization algorithm,lion pride optimizer(LPO),which is inspired by lion pride behavior.The framework is mainly based on lion prides’ evolution process and group living theory.In a lion pride,brutal competition of individuals happens among male lions both within and among prides;on the other hand,each member plays an important role in the persistence of a lion pride.Based on this framework,concepts from lion prides behavior,e.g.,the strongest males occupy nearly all mating resources,and if a new cohort of males is able to take over a pride,they will seek to kill young cubs sired by their predecessors,are employed metaphorically to design optimum searching strategies for solving continuous optimization problems.From the studies of the algorithm property,it is found that the LPO algorithm is not sensitive to most parameters,which shows the robustness of the algorithm and the parameters are not problemdependent.Central tendency of the algorithm is not found.It is found that the pride update strategy and brutal competition of individuals are two main factors that contribute to the performance of LPO.According to the test results on 23 famous benchmark functions,the LPO algorithm has better performance than the other seven state-of-the-art algorithms on both unimodal and multimodal benchmark functions;in the test of high-dimensional multimodal problems,LPO outperforms the other five algorithms on all benchmark functions.  相似文献   

3.
This paper proposes an improved particle swarm optimization (PSO) with iterative chaotic map with infinite collapses (ICMIC) perturbations (ICMICPSO) for global optimization of multimodal functions. The chaotic perturbation generated by the ICMIC is incorporated into the particle's velocity updating rule as self-feedback to make the particles have a larger potential space to fly. With the coefficient of chaotic perturbation decaying, the dynamics of ICMICPSO algorithm is a chaotic dynamics first and then a steepest descent dynamics. The proposed ICMICPSO method as hybrid optimization is tested on several widely used multimodal functions. Numerical results of the proposed algorithm are compared with that of some other Chaotic PSO variants available in the existing literature. The performance studies demonstrate that the effectiveness and efficiency of the proposed ICMICPSO approach are comparably to or better than that of the other CPSO variants for solving the global optimization of multimodal functions.  相似文献   

4.
In this article,a novel unordered classification rule list discovery algorithm is presented based on Ant Colony Optimization(ACO). The proposed classifier is compared empirically with two other ACO-based classification techniques on 26 data sets,selected from miscellaneous domains,based on several performance measures. As opposed to its ancestors,our technique has the flexibility of generating a list of IF-THEN rules with unrestricted order. It makes the generated classification model more comprehensible and easily interpretable.The results indicate that the performance of the proposed method is statistically significantly better as compared with previous versions of AntMiner based on predictive accuracy and comprehensibility of the classification model.  相似文献   

5.
Image classification is an essential task in content-based image retrieval.However,due to the semantic gap between low-level visual features and high-level semantic concepts,and the diversification of Web images,the performance of traditional classification approaches is far from users’ expectations.In an attempt to reduce the semantic gap and satisfy the urgent requirements for dimensionality reduction,high-quality retrieval results,and batch-based processing,we propose a hierarchical image manifold with novel distance measures for calculation.Assuming that the images in an image set describe the same or similar object but have various scenes,we formulate two kinds of manifolds,object manifold and scene manifold,at different levels of semantic granularity.Object manifold is developed for object-level classification using an algorithm named extended locally linear embedding(ELLE) based on intra-and inter-object difference measures.Scene manifold is built for scene-level classification using an algorithm named locally linear submanifold extraction(LLSE) by combining linear perturbation and region growing.Experimental results show that our method is effective in improving the performance of classifying Web images.  相似文献   

6.
Decision trees have three main disadvantages: reduced performance when the training set is small; rigid decision criteria; and the fact that a single "uncharacteristic" attribute might "derail" the classification process. In this paper we present ConfDTree (Confidence-Based Decision Tree) -- a post-processing method that enables decision trees to better classify outlier instances. This method, which can be applied to any decision tree algorithm, uses easy-to-implement statistical methods (confidence intervals and two-proportion tests) in order to identify hard-to-classify instances and to propose alternative routes. The experimental study indicates that the proposed post-processing method consistently and significantly improves the predictive performance of decision trees, particularly for small, imbalanced or multi-class datasets in which an average improvement of 5%-9% in the AUC performance is reported.  相似文献   

7.
QoS-aware routing algorithm is important in wireless multimedia sensor networks. This paper formulates a generalized QoS-aware routing model on the basis of multiple routing metrics and priorities of packets. We first introduce a 2D plain-based routing algorithm IPACR which improves the standard ant colony algorithm by optimizing the initial distribution of artificial pheromone in order to accelerate the algorithm convergence rate. Then a clustering-based routing algorithm ICACR is presented which can be well applied in a large scale network. ICACR is a variation of IPACR because it can be suitable for clustering cases to satisfy the larger scale situations. Both the numerical algorithm performance analysis and simulation of IPACR and ICACR are given. The results show that ICACR outperforms IPACR in terms of both network lifetime and QoS-aware routing metrics in large scale wireless multimedia sensor networks. Moreover, the simulation based on the real video traces shows that by extending the multi-path to ICACR for different priorities of video frames better performance can be achieved.  相似文献   

8.
To overcome the disadvantages of the location algorithm based on received signal strength indication(RSSI) in the existing wireless sensor networks(WSNs),a novel adaptive cooperative location algorithm is proposed.To tolerate some minor errors in the information of node position,a reference anchor node is employed.On the other hand,Dixon method is used to remove the outliers of RSSI,the standard deviation threshold of RSSI and the learning model are put forward to reduce the ranging error of RSSI and improve the positioning precision effectively.Simulations are run to evaluate the performance of the algorithm.The results show that the proposed algorithm offers more precise location and better stability and robustness.  相似文献   

9.
This paper presents a fast adaptive iterative algorithm to solve linearly separable classification problems in R n.In each iteration,a subset of the sampling data (n-points,where n is the number of features) is adaptively chosen and a hyperplane is constructed such that it separates the chosen n-points at a margin and best classifies the remaining points.The classification problem is formulated and the details of the algorithm are presented.Further,the algorithm is extended to solving quadratically separable classification problems.The basic idea is based on mapping the physical space to another larger one where the problem becomes linearly separable.Numerical illustrations show that few iteration steps are sufficient for convergence when classes are linearly separable.For nonlinearly separable data,given a specified maximum number of iteration steps,the algorithm returns the best hyperplane that minimizes the number of misclassified points occurring through these steps.Comparisons with other machine learning algorithms on practical and benchmark datasets are also presented,showing the performance of the proposed algorithm.  相似文献   

10.
To manipulate the layout analysis problem for complex or irregular document image, a Unified HMM-based Layout Analysis Framework is presented in this paper. Based on the multi-resolution wavelet analysis results of the document image, we use HMM method in both inner-scale image model and trans-scale context model to classify the pixel region properties, such as text, picture or background. In each scale, a HMM direct segmentation method is used to get better inner-scale classification result. Then another HMM method is used to fuse the inner-scale result in each scale and then get better final segmentation result. The optimized algorithm uses a stop rule in the coarse to fine multi-scale segmentation process, so the speed is improved remarkably. Experiments prove the efficiency of proposed algorithm.  相似文献   

11.
一种适用于多维的快速IP分类算法   总被引:6,自引:0,他引:6  
喻中超  徐恪  吴建平 《软件学报》2001,12(12):1801-1809
网络应用的发展要求路由器必须有能力支持防火墙、提供QoS、流量计费等一系列功能,这些功能都要求路由器对IP包进行分类以完成对数据包的不同处理.在Grid of Tries算法的基础上,提出了一种新的IP分类算法.该算法不仅克服了Grid of Tries算法在多维IP分类方面的局限性,而且在时间和空间性能上都优于Grid ofTries,是目前综合性能比较好的分类算法.  相似文献   

12.
Parallel Error Detection for Leading Zero Anticipation   总被引:1,自引:0,他引:1       下载免费PDF全文
The algorithm and its implementation of the leading zero anticipation (LZA) are very vital for the performance of a high-speed floating-point adder in today's state of art microprocessor design. Unfortunately, in predicting "shift amount" by a conventional LZA design, the result could be off by one position. This paper presents a novel parallel error detection algorithm for a general-case LZA. The proposed approach enables parallel execution of conventional LZA and its error detection, so that the error-indicatlon signal can be generated earlier in the stage of normalization, thus reducing the critical path and improving overall performance. The circuit implementation of this algorithm also shows its advantages of area and power compared with other previous work.  相似文献   

13.
An Effective Feedback Control Mechanism for DiffServ Architecture   总被引:1,自引:0,他引:1       下载免费PDF全文
As a scalable QoS(Quality of Service)architcture,DiffServ(Differentiated Service)mainly consists of two components:taffic conditioning at the edge of the DiffServ domain and simple packet forwarding inside the DiffServ domain.DiffServ has many advantages such as flexbility,scalability and simplicity.But when providing, AF (Assured Forwarding) services ,DiffServ has some problems such as unfairness among aggregated flows or among micro-flows belonging to an aggregated flow.In this paper,a feedback mechanism for AF aggregated flows is proposed to solve this problem.Simulation results show that this mechanism does improve the performance of DiffServ.Firt,it can improve the fairness among aggregated flows and make DiffServ more friendly toward TCP (Transmision Control Protocol)flows.Second,it can decrease the buffer requirements at the congested router and thus obtain lower delay and packet loss rate.Third,it also keeps almost the same link utility as in normal DiffServ,Einally,it is simple and easy to be implemented.  相似文献   

14.
In service oriented architecture (SOA), service composition is a promising way to create new services. However, some technical challenges are hindering the application of service composition. One of the greatest challenges for composite service provider is to select a set of services to instantiate composite service with end- to-end quality of service (QoS) assurance across different autonomous networks and business regions. This paper presents an iterative service selection algorithm for quality driven service composition. The algorithm runs on a peer-to-peer (P2P) service execution environment--distributed intelligent service execution (DISE), which provides scalable QoS registry, dynamic service selection and service execution services. The most significant feature of our iterative service selection algorithm is that it can work on a centralized QoS registry as well as cross decentralized ones. Network status is an optional factor in our QoS model and selection algorithm. The algorithm iteratively selects services following service execution order, so it can be applied either before service execution or at service run-time without any modification. We test our algorithm with a series of experiments on DISE. Experimental results illustrated its excellent selection and outstanding performance.  相似文献   

15.
Practical fast computation of Zernike moments   总被引:1,自引:1,他引:0       下载免费PDF全文
The fast computation of Zernike moments from normalized gometric moments has been developed in this paper,The computation is multiplication free and only additions are needed to generate Zernike moments .Geometric moments are generated using Hataming‘s filter up to high orders by a very simple and straightforward computaion scheme.Other kings of monents(e.g.,Legendre,pseudo Zernike)can be computed using the same algorithm after giving the proper transformaitons that state their relations to geometric moments.Proper normaliztions of geometric moments are necessary so that the method can be used in the efficient computation of Zernike moments.To ensure fair comparisons,recursive algorithms are used to generate Zernike polynoials and other coefficients.The computaional complexity model and test programs show that the speed-up factor of the proposed algorithm is superior with respect ot other fast and /or direct computations It perhaps is the first time that Zernike moments can be computed in real time rates,which encourages the use of Zernike moment features in different image retrieval systems that support huge databases such as the XM experimental model stated for the MPEG-7 experimental core.It is concluded that choosing direct copmutation would be impractical.  相似文献   

16.
A low complex minimum mean-square error frequency-domain decision feedback (MMSE-FDDF) equalization algorithm is proposed in this paper for the single-carrier V-BLAST systems. Exploiting the factor that the discrete Fourier transform (DFT) is unitary, the proposed receiver can equalize the signals by the MMSE detecting to the spectrums in the frequency domain instead of the waveforms in the time domain. In order to obtain the right decisions, the detector must be able to equalize the overall spectrum with regard to each layer. This work can be performed very efficiently since the system matrix has been designed as a special block-circulant-block matrix. Similar to other V-BLAST-like systems, the detecting order has strong impact on the performance of MMSE-FDDF. Therefore, we further give a fast optimally sorting scheme for the MMSE-FDDF architecture. By using the newly constructed matrix, the coefficients computation and the sorting can be combined into one process, and then we employ the modified Gram-Schmidt (MGS) to simplify the process. The simulation results and the computational complexity analysis show that the proposed MMSE-FDDF has better tradeoff between the performance and the complexity than the existing algorithms. In addition, MMSE-FDDF can avoid the performance floor caused by the overlap-and-save technique in the severe dispersive channel. Supported partially by the National Natural Science Foundation of China (Grant Nos. 60572046, 60502022, 60772095), the National High-Tech Research and Development Program of China (“863” Program)(Grant No. 2006AA01Z220)  相似文献   

17.
The IP packet forwarding of current Internet is mainly destination based. In the forwarding process, the source IP address is not checked in most cases.This causes serious security, management and accounting problems. Based on the drastically increased IPv6 address space, a "source address validation architecture" (SAVA) is proposed in this paper, which can guarantee that every packet received and forwarded holds an authenticated source IP address. The design goals of the architecture are lightweight, loose coupling, "multi-fence support" and incremental deployment. This paper discusses the design and implementation for the architecture, including inter-AS, intra-AS and local subnet. The performance and scalability of SAVA are described. This architecture is deployed into the CNGI-CERNET2 infrastructure a large-scale native IPv6 backbone network of the China Next Generation Internet project. We believe that the SAVA will help the transition to a new, more secure and dependable Internet.  相似文献   

18.
High performance Mandarin digit recognition(MDR)is much more difficult to achieve than its English counterpart,especially on inexpensive hardware implementation.In this paper,a new ,Multi-Layer Perceptrons(MLP)based postprocessor,an a posteriori probability estimator is presented and used for the rejection model of the speaker independent Mandarin digit recognition system based on hidden Markov model(HMM).Poor utterances,which are recognized by HMMs but have low a posteriori probability,will be rejected.After rejecting about 4.9% of the tested utteraces,the MLP rejection model can boost the digit recognition accuracy from 97.1%to 99.6%,The performance is better than those rejection models based on linear discrimiantion,likelihood ratio or anti-digit.  相似文献   

19.
OpenMP on Networks of Workstations for Software DSMs   总被引:3,自引:0,他引:3       下载免费PDF全文
This paper describes the implementation of a sizable subset of OpenMP on networks of workstations(NOWs) and the source-to-source OpenMP complier(AutoPar) is used for the JIAJIA home-based shared virtual memory system (SVM).The paper suggests some simple modifications and extensions to the OpenMP standard for the difference between SVM and SMP(symmetric multi processor),at which the OpenMP specification is aimed.The OpenMP translator is based on an automatic paralleization compiler,so it is possible to check the correctness of the semantics of OpenMP programs which is not required in an OpenMP-compliant implementation AutoPar is measured for five applications including both programs from NAS Parallel Benchmarks and real applications on a cluster of eight Pentium Ⅱ PCs connected by a 100 Mbps switched Eternet.The evaluation shows that the parallelization by annotaing OpenMPdirectives is simple and the performance of generatd JIAJIA code is still acceptable on NOWs.  相似文献   

20.
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