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In recent years, web-based attacks increase and become the top threat in cloud environments. To detect unknown web-based attacks, many studies resort to anomaly detection through analyzing web logs. This paper presents an anomaly detection approach, which includes a transforming model and a classifier model. The transforming model converts every entry into a vector, and every value in vector is obtained...
We consider multiple-antenna signal detection of primary user transmission signals by a secondary user receiver in cognitive radio networks. The optimal detector is analyzed for the scenario where the number of primary user signals is no less than the number of receive antennas at the secondary user. We first derive exact expressions for the moments of the generalized likelihood ratio test (GLRT)...
We consider multiple-antenna signal detection of primary user transmission signals by secondary user receivers in cognitive radio networks. The optimal detector is analyzed for the scenario where the number of primary user signals is no less than the number of receive antennas at the secondary users. We first derive exact expressions for the moments of the generalized likelihood ratio (GLRT) statistic,...
In this paper, the problem of distributed multiuser Opportunistic Spectrum Access is studied based on Partially Observable Markov Decision Process (POMDP), where the channels are partially observed by secondary users (SUs) constrained by hardware and energy. Considering the similarity of spectrum environment, the decision of every secondary user may be the same, which leads to collisions. Comparing...
In both human and machine vision systems, edges in images are of crucial significance in understanding the contents of images. Edge detection has therefore become an important task in image processing. In this paper, we propose a new operator for detecting edges in images. This operator is based on the principle of evaluating the local fluctuation of the pixel values. We first normalize the pixel...
For mobile multi-hop wireless network, IEEE 802.16j/MR network can not only supply large area wireless deployment, but also provide high quality network service to mobile users. In this paper, we will be focusing on QoS supporting for mobile users in the IEEE 802.16-MR network. The probability of a mobile user who visits a RS is known beforehand. With the same visiting probability of each RS and the...
Cyclic division algebras have been extensively utilized to design approximately universal codes. Their error probabilities can be intrinsically improved by a small integer non-norm element. This paper proves the insufficiency of existing encoding methods for obtaining the non-norm element 1+i over QAM and the numbers of transmit antennas: {n:8|n}. An improved method is then presented to overcome this...
Edges in images are considered to be basic low-level features in image processing and pattern recognition. In this paper, we propose a new method for edge detection using the exponential function. The pixel values within a mask are normalized so that they can be regarded as probabilities. Then, the sum of the exponential or the reciprocal of exponential functions of the probabilities is calculated...
Detecting edges in images is a fundamental and useful technique in image processing. In this paper, we propose a new variance operator for edge detection. The pixel values within a mask are normalized so that they can be treated as probabilities. Then, the variance of the probabilities is calculated. A threshold is chosen for generating the black and white edge image. Morphological operation is applied...
In this paper, we propose a Maximum a Posteriori (MAP) method which combined Markov Random Field (MRF) and the feature of vessel-like feature of the angiograms. As considering the advantages from both, the proposed method is sensitive to the vessel-like structures in the angiograms and robust to noise. Hence, it is able to extract the details of the vessels while at the same time reducing the noises...
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