Some problems involved with passwords and user authentication are discussed. Making poor password choices, which leave them vulnerable to password cracking tools and social engineering, is one common problem. Other pr...
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Some problems involved with passwords and user authentication are discussed. Making poor password choices, which leave them vulnerable to password cracking tools and social engineering, is one common problem. Other problems include, sharing them with friends and colleagues, writing the information down, using the same password for long periods and using the same password on multiple systems. Other options for user authentication, such as biometrics, are also discussed.
Mobility in ad hoc networks causes frequent link failures, which in turn causes packet losses. TCP attributes these packet losses to congestion. This incorrect inference results in frequent TCP re-transmission time-ou...
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This paper presents the development of tunable filters using ohmic contact microelectromechanical system switches. It is shown that this type of switch is very well suited for the fabrication of low-loss high tuning-r...
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This paper presents the development of tunable filters using ohmic contact microelectromechanical system switches. It is shown that this type of switch is very well suited for the fabrication of low-loss high tuning-range microwave filters. Two sets of tunable K u-band microstrip filters and resonators have been fabricated, with measured tuning ranges of 20% and 44%, and unloaded quality factors better than 75 in all cases. The 2-bit 5.7% fractional bandwidth, tunable bandpass filters exhibit insertion losses lower than 3.2 dB in all states.
An analytical model for the carrier density at the accumulation layer of TIGBT (Trench Insulated Gate Transistor) is presented in terms of the aspect ratio with the influence of the depth of the trench gate below the ...
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A parallel unconditionally stable solver for three-dimensional convection-diffusion equations is proposed by applying the upwind Crank-Nicolson difference sch.mes combined with alternating bar parallelization. This so...
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A parallel unconditionally stable solver for three-dimensional convection-diffusion equations is proposed by applying the upwind Crank-Nicolson difference sch.mes combined with alternating bar parallelization. This solver can be applied numerically to any variation of convection-diffusion equations with Dirichlet boundary conditions. Making use of a fractional step iteration technique for linear systems, this approach yields good runtime performance. To validate the accuracy and efficiency of the method, sample experiments are done on a software tool, Codie4D, which was implemented using the MPICH library.
Contrary to current wireless network systems, ubiquitous network environment has quite dynamic and diversified devices which aim at best meeting the requirements of specific group of users for a specific purpose. In o...
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ISBN:
(纸本)1932415262
Contrary to current wireless network systems, ubiquitous network environment has quite dynamic and diversified devices which aim at best meeting the requirements of specific group of users for a specific purpose. In order to obtain the seamless transparency within mobile devices, accurate and efficient monitoring of dynamically changing environments is one of the most important requirements for ubiquitous network environments. In this paper, we describe the novel agent-based embedded monitoring systems for wireless network devices. By utilizing the light-weight mobile agent technology, our monitoring system can be a useful tool for ubiquitous network environments. This agent-based approach, moreover, provides seamless transparency. Our proposed monitoring system can automate the installation and updating process of monitoring code. We also implement our agent-based monitoring system on embedded Linux-based wireless ad hoc network testbed.
Background: In this paper we discuss an efficient methodology for the image analysis and characterization of digital images containing skin lesions using Support Vector Machines and present the results of a preliminar...
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Background: In this paper we discuss an efficient methodology for the image analysis and characterization of digital images containing skin lesions using Support Vector Machines and present the results of a preliminary study. Methods: The methodology is based on the support vector machines algorithm for data classification and it has been applied to the problem of the recognition of malignant melanoma versus dysplastic naevus. Border and colour based features were extracted from digital images of skin lesions acquired under reproducible conditions, using basic image processing techniques. Two alternative classification methods, the statistical discriminant analysis and the application of neural networks were also applied to the same problem and the results are comp.red. Results: The SVM (Support Vector Machines) algorithm performed quite well achieving 94.1% correct classification, which is better than the performance of the other two classification methodologies. The method of discriminant analysis classified correctly 88% of cases (71% of Malignant Melanoma and 100% of Dysplastic Naevi), while the neural networks performed approximately the same. Conclusion: The use of a comp.ter-based system, like the one described in this paper, is intended to avoid human subjectivity and to perform specific tasks according to a number of criteria. However the presence of an expert dermatologist is considered necessary for the overall visual assessment of the skin lesion and the final diagnosis.
We present efficient and robust algorithms for intersecting a freeform surface with a ringed surface or a ruled surface. A ringed surface is given as a one-parameter family of circles. By comp.ting the intersection be...
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ISBN:
(纸本)0769520782
We present efficient and robust algorithms for intersecting a freeform surface with a ringed surface or a ruled surface. A ringed surface is given as a one-parameter family of circles. By comp.ting the intersection between a freeform surface and each circle in the family, we can solve the intersection problem. We propose two approaches which are closely related to each other. The first approach detects certain critical points;and the intersection curve is constructed by connecting them in a correct topology. The second approach converts the intersection problem to that of finding the zero-set of two polynomial equations in the parameter space. The intersection between a freeform surface and a ruled surface can be comp.ted in a similar way.
Low comp.exity is very important for an adaptive loading algorithm used in OFDM systems in order to adapt the transmit power and the number of bits for each subcarrier within the coherence time of a wireless and mobil...
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Radial basis probability neural network (RBPNN) was introduced to recognize radar emitter signals. The structure and training algorithm of RBPNN were firstly discussed. Then, a novel feature extraction approach called...
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Radial basis probability neural network (RBPNN) was introduced to recognize radar emitter signals. The structure and training algorithm of RBPNN were firstly discussed. Then, a novel feature extraction approach called resemblance coefficient method and its detailed steps were presented. Finally, based on resemblance coefficient features, RBPNN was used to design classifer to identify 9 typical radar emitter signals. Because RBPNN inherits the advantages of both radial basis function neural network and probability neural network, RBPNN has the good characteristics of simple structure, fast learning speed and strong capabilities of pattern recognition and classification. Experimental results show that high accurate recognition rates are achieved and the introduced approach is effective and practical.
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