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971.
Skin detection has been considered as the principal step in many machine vision systems, such as face detection and adult
image filtering. Among all these techniques, skin color is the most welcome cue because of its robustness. However, traditional
color-based approaches poorly perform on the classification of skin-like pixels. In this paper, we propose a new skin detection
method based on the cascaded adaptive boosting (AdaBoost) classifier, which consists of minimum-risk based Bayesian classifier
and models in different color spaces such as HSV (hue-saturation-value), YCgCb (brightness-green-blue) and YCgCr (brightness-green-red).
In addition, we have constructed our own database that is larger and more suitable for training and testing on filtering adult
images than the Compaq data set. Experimental results show that our method behaves better than the state-of-the-art pixel-based
skin detection techniques on processing images with skin-like background. 相似文献
972.
Most efficient indeces and query techniques over XML (extensible markup language) data are based on a certain labeling scheme, which can quickly determine ancestor-descendant and parent-child relationship between two nodes. The current basic labeling schemes such as containment scheme and prefix scheme cannot avoid relabeling when XML documents are updated. After analyzing the essence of existing dynamic XML labels such as compact dynamic binary string (CDBS) and vector encoding, this paper gives a common unifying framework for the numeric-based generalized dynamic label, which can be implemented into a variety of dynamic labels according to the different user-defined value comparison methods. This paper also proposes a novel dynamic labeling scheme called radical sign label. Extensive experiments show that the radical sign label performs well for the initialization, insertion and query operations, and especially for skewed insertion where the storage cost of the radical sign label is better than that of former methods. 相似文献
973.
The so called "alterable-element method" (AEM) was introduced to deal with the coupling interac-tion of vehicle and sub-structure considering the actual transient jump of wheel, while the classical "contact allalong" assumption based on which wheels and lower structure are always contact was abandoned. The alterableelement used in this method is a conceptional element, which is used to calculate the coupling interaction ofupper and lower structures and has some typical characteristics: firstly it flows along with the moving of contactpoint; secondly whether it is used for calculation depends on the contact state; thirdly its sizes could changeaccording to specific problems and so on. VISUAL FORTRAN program was coded, and different moving vehiclemodels were presented taking into consideration the effects of random corrugation in the numerical study. Thenumerical solutions are favored comparing with the results obtained by alternative methods when there is nojump phenomenon existed. With abrupt irregularity, the transient jump of wheel was studied using the presentmethod. 相似文献
974.
A vector autoregressive model was developed for a sample of container carrier time charter rates.Although the series of time charter rates are themselves found non-stationary, thus precluding the use of manymodeling methodologies, evidence provided by co-integration tests points to the existence of stable long-termrelationships between the series. An assessment of the forecasts derived from the model suggests that the spec-ification of these long-term relationships does not improve the accuracy of long-term forecasts. These resultsare interpreted as a corroboration of the efficient market hypothesis. 相似文献
975.
The parallel processing based on the free running model test was adopted to predict the interac-tion force coefficients (flow straightening coefficient and wake fraction) of ship maneuvering. And the multi-population genetic algorithm (MPGA) based on real coding that can contemporarily process the data of freerunning model and simulation of ship maneuvering was applied to solve the problem. Accordingly the optimalindividual was obtained using the method of genetic algorithm. The parallel processing of multi-populationsolved the prematurity in the identification for single population, meanwhile, the parallel processing of the dataof ship maneuvering (turning motion and zigzag motion) is an attempt to solve the coefficient drift problem.In order to validate the method, the interaction force coefficients were verified by the procedure and thesecoefficients measured were compared with those ones identified. The maximum error is less than 5%, and theidentification is an effective method. 相似文献
976.
A network plan model of ship erection was established based on the network planning technologyand the work-package breakdown system. The load-oriented production control method was introduced to buildup a throughput diagram model thus it is possible to describe the ship erection process numerically. Based onthe digitaiized models some cases of production balance of ship erection were studied and three balance indexeswere put forward, they are the load balance rate, the input manpower balance rate and the maximum gantrycrane operating times. Such an analytic method based on the balance evaluation is the important foundationfor digitization and intelligentization of shipyard production management. 相似文献
977.
Structural intensity characterization of composite laminates subjected to impact load 总被引:2,自引:0,他引:2
Structural intensity (SI) characterization of composite laminates subjected to impact load was dis-cussed. The SI pattern of the laminates which have different fiber orientations and boundary conditions wasanalyzed. The resultant forces and velocities of the laminates were calculated, and the structural intensity wasevaluated. The SI streamlines of carbon fiber reinforced epoxy composite laminates and the steel plates werediscussed. The results show that the SI streamlines of the graphite/epoxy laminates are different from that ofthe steel plates, and the SI streamlines are influenced by the boundaries, the stacking sequence of the compositelaminates. The change of the historical central displacement of the graphite/epoxy laminates is fasten thanthat of the steel plates. 相似文献
978.
This paper investigates exact performance of an amplify-and-forward (AF) relay system based on water-filling power allocation in Nakagami-m fading environment, where m is a nonnegative integer plus one half. We first offer the cumulative distribution function (CDF) and probability density function (PDF) of the received signal-to-noise ratio (SNR) at a destination. Then outage probability, moments of SNR, higher-order statistics of the capacity are explicitly conducted. Especially, average symbol error rate (SER) under an additive white generalized Gaussian noise (AWGGN) is developed for water-filling power allocation scheme. While the average SER subjected by an additive white Gaussian noise (AWGN) can be regarded as a special case. Finally, all theoretical formulas are truly attested by various simulation results. 相似文献
979.
The goal of salient object detection is to estimate the regions which are most likely to attract human’s visual attention. As an important image preprocessing procedure to reduce the computational complexity, salient object detection is still a challenging problem in computer vision. In this paper, we proposed a salient object detection model by integrating local and global superpixel contrast at multiple scales. Three features are computed to estimate the saliency of superpixel. Two optimization measures are utilized to refine the resulting saliency map. Extensive experiments with the state-of-the-art saliency models on four public datasets demonstrate the effectiveness of the proposed model. 相似文献
980.
Based on simulated annealing (SA), automatically finding the number of clusters (AFNC) is proposed in this paper to determine the number of clusters and their initial centers. It is a simple and automatic method that combines local search with two widely-accepted global analysis techniques, namely careful-seeding (CS) and distance-histogram (DH). The procedure for finding a cluster is formulated as mountain-climbing, and the mountain is defined as the convergent domain of SA.When arriving at the peak of one mountain, AFNC has found one of the clusters in the dataset, and its initial center is the peak. Then, AFNC continues to climb up another mountain from a new starting point found by CS till the termination condition is satisfied. In the procedure of climbing-up mountain, the local dense region for searching the next state of SA is found by analyzing the distance histogram. Experimental results show that AFNC can achieve consistent performance for a wide range of datasets. 相似文献