The difference equation x(t) = ∑s=t-Tt-1 F (s, x(s)) is used to model the spread of infectious disease. Here, x(t) represents the proportion of the population infected at time t, F(t, x(t)) denotes the proportion of ...
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ISBN:
(纸本)9810474806
The difference equation x(t) = ∑s=t-Tt-1 F (s, x(s)) is used to model the spread of infectious disease. Here, x(t) represents the proportion of the population infected at time t, F(t, x(t)) denotes the proportion of the population newly infected between times t and (t + 1), and T is the length of time an individual remains infectious. Criteria will be established for the existence of a nontrivial and nonnegative periodic solution for the difference equation. The results are easy to implement numerically, and only require basic information of the contact rate q(t) = limx&rarr0 F(t,x)/x. An algorithm and some illustrative examples will be given.
In many cases where object identification is necessary complete boundaries are not available due to poor contrast or occlusion. In such cases global shape descriptors are not effective. We describe a multi-resolution ...
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In many cases where object identification is necessary complete boundaries are not available due to poor contrast or occlusion. In such cases global shape descriptors are not effective. We describe a multi-resolution hypothesise and verify method for matching characteristic local segments of a boundary with pre-defined models. Boundary shape is characterised using a model of the distribution of dominant points within an image. A multi-resolution pyramid is used to define, at the corner of each tile, anchor points for one end of virtual springs;the other end of each virtual spring is attached to a selec.ed "dominant point" on the boundary. The virtual force at each corner is retained as a descriptor for that point in the pyramid. The dominant boundary points are selec.ed by identifying points that exhibit significant curvature at a range of scales. The performance of this algorithm was evaluated using objects that are similar in appearance. With 20% of the boundary occluded 100% correct recognition was achieved and with 50% occlusion the correct recognition rate was 63%. Noise sensitivity was evaluated by the addition of boundary displacement noise with a standard deviation of up to ± 5 pixels (± 5-10%). At this noise level the correct recognition rate fell from 100% to 93% and a greater depth of search (in resolution) was required to establish a high level of confidence in object recognition.
Accurate measurements are essential for feature extraction and accurate control of systems. Often, however, accurate measurements cannot be performed directly due to the inaccessibility in systems to place sensors or ...
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Accurate measurements are essential for feature extraction and accurate control of systems. Often, however, accurate measurements cannot be performed directly due to the inaccessibility in systems to place sensors or non-ideal sensor characteristics. Inference measurements (also called soft sensors) enables estimates of variables in a system from directly measurable variables. This paper shows which directly accessible variables should be used for accurate inference by exploring various systems. Neural networks have universal mapping capabilities, and is used to perform inference measurements on nonlinear dynamic systems. The results show which variables should be used in order to perform accurate inference of unknown variables.
It is often desirable that manufacturers and users can convert the reference white of display into the preferred color temperature that is one of representative color characteristics of a light source. An efficient me...
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It is often desirable that manufacturers and users can convert the reference white of display into the preferred color temperature that is one of representative color characteristics of a light source. An efficient method of correcting color reproduction error is proposed for displaying the NTSC-based video signal in plasma display panel televisions (PDP-TVs) and is also shown to be successfully coupled with flexible color temperature conversion based on the signal processing technique. As a result, this method can contribute to providing a range of user-preferred color temperature in PDP-TVs.
A method for automatic and fast shot detection for the MPEG video is proposed. Shot detection is the first step in analyzing and searching a large amount of video data. Our proposed method is based on activity of imag...
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A method for automatic and fast shot detection for the MPEG video is proposed. Shot detection is the first step in analyzing and searching a large amount of video data. Our proposed method is based on activity of images as well as intra MBs in the video frame. It is possible to detect scene changes rapidly by using information from the compressed MPEG video data without the need for full-frame decoding. Experimental results show that the proposed method can provide good performance at a low computational cost.
This paper proposes a new multispectral image data compression algorithm that can efficiently reduce spatial and spectral redundancies by applying classified prediction, a Karhunen-Loeve transform (KLT), and the three...
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This paper proposes a new multispectral image data compression algorithm that can efficiently reduce spatial and spectral redundancies by applying classified prediction, a Karhunen-Loeve transform (KLT), and the three-dimensional set partitioning in hierarchical trees (3-D SPIHT) algorithm in the wavelet transform (WT) domain. The classification is performed in the WT domain to exploit the interband classified dependency, while the resulting class information is used for the interband prediction. The residual image data on the prediction errors between the original image data and the predicted image data is decorrelated by a KLT. Finally, the 3-D SPIHT algorithm is used to encode the transformed coefficients listed in a descending order spatially and spectrally as a result of the WT and KLT. Simulation results showed that the reconstructed images after using the proposed algorithm exhibited a better quality and higher compression ratio than those using conventional algorithms.
The current paper presents a CORBA based core middleware architecture for supporting seamless interoperability in an IEEE1394-based home network. To support CORBA on top of an IEEE139-based home network, a CORBA progr...
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The current paper presents a CORBA based core middleware architecture for supporting seamless interoperability in an IEEE1394-based home network. To support CORBA on top of an IEEE139-based home network, a CORBA programming platform is designed and implemented without any loss of the real-time properties of the IEEE1394 protocol. To customize the real-time CORBA properties using the IEEE1394 protocol, first, a specially designed device driver for the IEEE1394 adaptor is developed based on an RT-Linux kernel. On top of the device driver, an IEEE1394 ORB is also designed and implemented to support CORBA. The proposed ORB consists of two components. One is the IEEE 1394 asynchronous ORB according to the GIOP specification of CORBA to support interoperability with other ORBs, such as IIOP, and the other is the IEEE1394 isochronous ORB to retain the real-time properties of the IEEE1394 protocol. The performance of the proposed CORBA based core middleware platform is verified based on a prototype home network test-bed.
In this paper steady-state models of versatile FACTS devices are formulated based on the PIM and incorporated into the OFF. By incorporating the control capabilities provided by FACTS devices into the OFF, the control...
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ISBN:
(纸本)0780384652
In this paper steady-state models of versatile FACTS devices are formulated based on the PIM and incorporated into the OFF. By incorporating the control capabilities provided by FACTS devices into the OFF, the control of transmission system becomes more flexible and it largely increases the degree of freedom for OFF solution space. The proposed OFF problem was solved with Sequential Quadratic Programming (SQP) in the MATLAB environment. Numerical results demonstrate the good performance of the OPF approach in handling the power flow control problem, voltage stability enhancement and congestion relief with various FACTS devices.
A character-embedded watermarking algorithm is proposed for copyright protection of satellite images based on the Fast Hadamard transform (FHT). The algorithm has the advantage of easy software and hardware implementa...
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A character-embedded watermarking algorithm is proposed for copyright protection of satellite images based on the Fast Hadamard transform (FHT). The algorithm has the advantage of easy software and hardware implementation as well as speed, compared to other orthogonal transforms such as Cosine, Fourier and wavelet transform.
This paper considers the 3D reconstruction problem from an image sequence taken by a camera with constant internal parameters. Stratified method starts from a projective reconstruction, refines it into affine reconstr...
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ISBN:
(纸本)9810483643
This paper considers the 3D reconstruction problem from an image sequence taken by a camera with constant internal parameters. Stratified method starts from a projective reconstruction, refines it into affine reconstruction and finally upgrades it to metric reconstruction. It was reported that the most difficult step is to obtain the affine reconstruction, that is, to find the plane at infinity in the projective coordinate frame. In this paper, we give a simple linear solution to estimate the location of infinity plane when the camera's rotation is small. The developed method depends on the linear relationship among three main diagonal elements of the infinity homography of such two views. Three images are sufficient to give one unique solution, which can be used as the start point of nonlinear constraints. Simulations showed that out algorithm gives very close estimation to the exact location of the plane of infinity.
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