Internal strain resulting from tissue deformation can be estimated by correlation of speckle patterns within radio frequency (RF) ultrasound images. For large deformations, random correlations between speckle kernels ...
详细信息
ISBN:
(纸本)9781424424283
Internal strain resulting from tissue deformation can be estimated by correlation of speckle patterns within radio frequency (RF) ultrasound images. For large deformations, random correlations between speckle kernels may exceed the true peak. In this study, we use the viterbi algorithm to overcome peak hopping artifacts. RF data were generated for an average strain of 5%. Simulations were performed for a medium with an inclusion at the center of elastic modulus 6 times that of the surrounding medium. Results show that viterbi processing can significantly reduce peak hopping.
Satellite Internet (SI) is an essential component of 6G as an effective supplement to terrestrial Internet in the future. Owing to its relatively limited processing power and bandwidth, distributed denial of service (...
详细信息
ISBN:
(纸本)9781665435406
Satellite Internet (SI) is an essential component of 6G as an effective supplement to terrestrial Internet in the future. Owing to its relatively limited processing power and bandwidth, distributed denial of service (DDoS) attacks may cause substantial damage. Moreover, the complexity and difficulty of defense also increase due to the constantly changing topology scale of SI when supporting various applications. Therefore, path tracking must be maintained with high precision at different scales to realize protection at the boundary. However, the marking rate limits traditional packet marking methods, causing a decrease in the tracking accuracy when the topology is expanded. Therefore, we propose a scalable traffic path tracking (TPT) scheme. Firstly, a lightweight description of malicious traffic in the entire network is realized by improving a multi-dimensional traffic feature digesting method. Secondly, the connection relationship sparse matrix of nodes is obtained based on the Hidden Markov Model modeling of the network topology and attack scenarios. These generate the observation probability matrix B and transition probability matrix A of the traditional viterbi algorithm. Finally, we optimize the viterbi algorithm by adding an index matrix of the next-largest probability value to eliminate tracking loops, thereby achieving high tracking accuracy for topologies of different scales. The Keysight Ixia platform is used to generate malicious traffic in the experiments. The results demonstrate that the scheme can maintain a tracking accuracy of over 99% against various DDoS attacks in topologies of different scales, which is more accurate and scalable than existing methods.
Line following robots requires image acquisition and processing algorithms for the determination of the line trajectory. The viterbi algorithm is proposed for the estimation of the line trajectory in this paper. The r...
详细信息
ISBN:
(纸本)9781479950812
Line following robots requires image acquisition and processing algorithms for the determination of the line trajectory. The viterbi algorithm is proposed for the estimation of the line trajectory in this paper. The robustness of this algorithm is verified using the Monte Carlo approach for two distortions types: additive Gaussian noise and false lines sets. The results show possibilities of reliable estimation, even if the real line is hidden in the noise, without the application of additional estimators based on the previous measurements.
Symbol detection plays an important role in the implementation of digital receivers. One of the most common symbol detection schemes is the viterbi algorithm, which is capable of achieving the minimal probability of e...
详细信息
ISBN:
(纸本)9781538665282
Symbol detection plays an important role in the implementation of digital receivers. One of the most common symbol detection schemes is the viterbi algorithm, which is capable of achieving the minimal probability of error under a broad range of channels encountered in practice. The viterbi algorithm is based on channel state information (CSI);it requires that the receiver knows exactly (or approximately) the statistical relationship between the channel input and output. In some cases, such knowledge may be unavailable or very difficult to obtain. In this work, we propose viterbiNet, which is a data-driven symbol detector obtained by converting the viterbi algorithm into a system utilizing deep neural networks (DNNs). The resulting detector thus operates without CSI. We identify the specific parts of the viterbi algorithm that are model-based, and design the DNN to implement those computations. Our numerical evaluations demonstrate that the performance of viterbiNet, which is ignorant of the CSI, approaches that of the optimal CSI-based viterbi algorithm. Moreover, unlike conventional viterbi detection, viterbiNet is robust to model uncertainty. Our results demonstrate the conceptual benefit of designing DNN-based communication systems to implement established algorithms.
This paper improves the conventional viterbi algorithm so that it can be used for decoding the convolutional code with a large constraint length and a very low rate. Through the construction of a Hamming distance tabl...
详细信息
ISBN:
(纸本)8955191235
This paper improves the conventional viterbi algorithm so that it can be used for decoding the convolutional code with a large constraint length and a very low rate. Through the construction of a Hamming distance table, the novel algorithm greatly improved the performance of the old one. Simulation results indicate that this algorithm could be successfully applied to attack stream cipher, whose LFSR sequence error code rate is 37% and feedback polynomial degree is 60, moreover, the decoding efficiency is about 10 times the conventional one.
viterbi algorithm is a commonly used algorithm for Gaussian filtered minimum frequency shift keying (GMSK) demodulation, but there exist some problems such as large delay, high overhead, and data overflow in the hardw...
详细信息
ISBN:
(纸本)9781728172019
viterbi algorithm is a commonly used algorithm for Gaussian filtered minimum frequency shift keying (GMSK) demodulation, but there exist some problems such as large delay, high overhead, and data overflow in the hardware implementation. Aiming at the problems of delay and overhead, we propose a novel update rule to optimize the stored transfer-state information table and realize one-step backtracking in this paper. It also ensures the realization of pipeline operation, reduces demodulation delay, and saves hardware resources. Furthermore, we adopt combinational logic to perform pre-decision, which not only satisfies the timing requirements, but also achieves the anti-overflow. The hardware implementation results demonstrate the feasibility and correctness of the design.
A new method of image resolution up-conversion based on maximum a posteriori sequence estimation is proposed. At each missing pixel of the high resolution (HR) image we consider an ensemble of candidate interpolation ...
详细信息
ISBN:
(纸本)9781467325332;9781467325349
A new method of image resolution up-conversion based on maximum a posteriori sequence estimation is proposed. At each missing pixel of the high resolution (HR) image we consider an ensemble of candidate interpolation methods (interpolator). The interpolators are interpreted as states of a finite-state machine (FSM). Accordingly, the up-scaling problem is converted to the problem of estimating the optimal sequence of interpolators corresponding to the sequence of missing HR pixel positions. We derive a parameter-free probabilistic model for this FSM to solve the estimation problem using trellis diagrams and viterbi algorithm. The experimental results prove that the proposed algorithm results sharper HR images and higher peak signal-to-noise ratios (PSNR) comparing to many algorithms in this domain.
This paper presents a method for separating cochannel FM signals. We show that the viterbi algorithm, traditionally limited to estimation of digital sequences, can jointly track analog FM signals by separately quantiz...
详细信息
ISBN:
(纸本)0780344286
This paper presents a method for separating cochannel FM signals. We show that the viterbi algorithm, traditionally limited to estimation of digital sequences, can jointly track analog FM signals by separately quantizing the derivatives of their instantaneous frequencies. We employ per-survivor processing in the trellis to estimate unknown channel effects. The approach works well when the signal to interference ratio (SIR) is less than or equal to zero, in contrast to conventional interference suppression algorithms that degrade as SIR approaches zero and fail catastrophically when SIR < 0. Comparisons of mean squared error (MSE) between the estimates and the true signals are given for varying SIR, SNR, Doppler offsets, and frequency deviations. The same approach can also be used for any other continuous phase modulation scheme, such as continuous-phase frequency-shift keying (CPFSK).
The most famous error-decoding algorithm for convolutional codes is the viterbi algorithm. In this paper, we present a new reduced complexity version of this algorithm which can be applied to a class of binary convolu...
详细信息
ISBN:
(纸本)9798350382853;9798350382846
The most famous error-decoding algorithm for convolutional codes is the viterbi algorithm. In this paper, we present a new reduced complexity version of this algorithm which can be applied to a class of binary convolutional codes with optimum column distances called k-partial simplex convolutional codes.
A new block-delayed partitioned viterbi algorithm (BD-PVA) receiver for the MIMO frequency-selective fading channel is proposed. The classic PVA has a trellis detector for each transmit antenna and feeds back tentativ...
详细信息
ISBN:
(纸本)9781479984060
A new block-delayed partitioned viterbi algorithm (BD-PVA) receiver for the MIMO frequency-selective fading channel is proposed. The classic PVA has a trellis detector for each transmit antenna and feeds back tentative decisions between these trellis detectors. The proposed algorithm uses more reliable temporary decisions in the feedback loop instead of the tentative decisions, thus resulting in an improved BER performance. MIMO systems with higher number of antennas exhibit a more remarkable BER performance improvement since they rely more on the feedback between the trellis detectors.
暂无评论