Electronics
Ali Mahani; Mojtaba Arab nezhad
Abstract
Approximate computing is considered a promising way to design high-performance and low-power arithmetic units recently. This paper proposes an energy-efficient logarithmic multiplier for error-tolerant applications. The proposed multiplier uses a novel technique to calculate the powers of two products ...
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Approximate computing is considered a promising way to design high-performance and low-power arithmetic units recently. This paper proposes an energy-efficient logarithmic multiplier for error-tolerant applications. The proposed multiplier uses a novel technique to calculate the powers of two products to reduce critical path complexity. Also, a correction term is provided to improve the multiplier accuracy. Additionally, the use of approximate adders in our design is investigated, and optimal truncation length is obtained through simulations. We evaluated our work both in accuracy and hardware criteria. Experiments on a 16-bit proposed multiplier with approximate adder show that power-delay product (PDP) is significantly reduced by 34.05% compared to the best logarithmic multipliers available in the literature, while the mean relative error distance (MRED) is also decreased by 21.1%. The results of embedding our multiplier in the dequantization step of the JPEG standard show that the image quality is improved in comparison with other logarithmic multipliers; Also, a subtle drop in image quality compared to utilizing exact multipliers proves the viability of our design.
Control
Mats Leon Richter; Leila Malihi; Anne-Kathrin Patricia Windler; Ulf Krumnack
Abstract
The predictive performance of a neural network depends on the one hand on the difficulty of a problem, defined by the number of classes and complexity of the visual domain, and on the other hand on the capacity of the model, determined by the number of parameters and its structure. By applying ...
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The predictive performance of a neural network depends on the one hand on the difficulty of a problem, defined by the number of classes and complexity of the visual domain, and on the other hand on the capacity of the model, determined by the number of parameters and its structure. By applying layer saturation and logistic regression probes, we confirm that these factors influence the inference process in an antagonistic manner. This analysis allows the detection of over- and under-parameterization of convolutional neural networks. We show that the observed effects are independent of previously reported pathological patterns, like the “tail pattern”. In addition, we study the emergence of saturation patterns during training, showing that saturation patterns emerge early in the optimization process. This allows for a quick detection of problems and potentially decreased cycle-time during experiments. We also demonstrate that the emergence of tail patterns is independent of the capacity of the networks. Finally, we show that information processing within a tail of unproductive layers is different, depending on the topology of the neural network architecture.
Electronics
shabnam sadeghi; Ali Mahani
Abstract
Stochastic computing (SC) method is a low-cost alternative to conventional binary computing, which processes digital data in the form of pseudo-random bit-streams and because of its highly redundant encoding format, bit-flip errors have a slight effect on the signal final value. As a result, this computational ...
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Stochastic computing (SC) method is a low-cost alternative to conventional binary computing, which processes digital data in the form of pseudo-random bit-streams and because of its highly redundant encoding format, bit-flip errors have a slight effect on the signal final value. As a result, this computational method is used for fault-tolerant digital applications. In this paper stochastic computing has been chosen to implement 2- dimensional discrete wavelet transform (2-D DWT) as a case study. The performance of this circuit is analyzed through two different faulty experiments. The results show that stochastic 2-D DWT outperforms binary implementation. Although stochastic computing provides inherent fault tolerance, we proposed four structures based on dual modular redundancy to improve the stochastic computing reliability. Improving the reliability of the stochastic circuits with the least area overhead is considered the main objective in these structures. The proposed methods are applied to improve the reliability of stochastic wavelet transform circuits. Experimental results show that all proposed structures improve the reliability of stochastic circuits, especially in extremely noisy conditions where fault tolerance of SC is reduced.
Power
Ahmad Ghaffari Gousheh; Mohsen Saniei; Morteza Razzaz; Alireza Saffarian
Abstract
Increase of the penetration level of distributed generation (DG) units in radial power distribution systems can increase the level of short circuits in these networks. Increasing the short circuit level can have destructive effects such as exceeding the tolerable current of the equipment as well as disrupting ...
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Increase of the penetration level of distributed generation (DG) units in radial power distribution systems can increase the level of short circuits in these networks. Increasing the short circuit level can have destructive effects such as exceeding the tolerable current of the equipment as well as disrupting the protective coordination in the network. The active superconducting fault current limiter (ASFCL) is a new device that has the ability of fault current limiting using voltage series compensation. In this paper, the modeling of ASFCL and control strategies including fault detection and converter performance in normal and fault modes are discussed. Initially, by simulating a sample three-phase system with ASFCL, its performance in limiting the fault current is investigated. In the next step, three operating modes including normal mode, upstream fault mode, and downstream fault mode are proposed to achieve an adaptive FCL that solves the mentioned problems in the grid-connected microgrid. The simulation results confirm the proper performance of ASFCL modes in both fault current limiting and protective coordination of overcurrent relays in the network.
Power
Mezhoud Nabil; Amarouayache Mohamed
Abstract
This paper presents one of the optimization method based on the newest stochastic search algorithm such as Gravitational Search Algorithm (GSA) to solve the Optimal Power Flow (OPF) Combined Economic Dispatch with Valve-Point Effect and Emission Index (EI) in electrical power networks. Our main goal ...
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This paper presents one of the optimization method based on the newest stochastic search algorithm such as Gravitational Search Algorithm (GSA) to solve the Optimal Power Flow (OPF) Combined Economic Dispatch with Valve-Point Effect and Emission Index (EI) in electrical power networks. Our main goal is to minimize the objective function necessary for a best balance between the energy production and its consumption which is presented in a nonlinear function, taking into account of equality and of inequality constraints. The objective is to minimize the total cost of active generations, the active power losses and the emission index. GSA method have been examined and tested on the standard IEEE 30-bus test system with various objective functions. The simulation results of used methods have been compared and validated with those reported in the recent literature. The results are promising and show the effectiveness and robustness of used method. It should be mentioned that from the base case, the cost generation, the active power losses and the emission index are significantly reduced.
Electronics
Mohammadreza Ghafari; Abdollah Amirkhani; Elyas Rashno; Shirin Ghanbari
Abstract
This paper is an extension of our previous research on presenting a novel Gaussian Mixture-based (MOG2) Video Coding for CCTVs. The aim of this paper is to optimize the MOG2 algorithm used for foreground-background separation in video streaming. In fact, our previous study showed that traditional video ...
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This paper is an extension of our previous research on presenting a novel Gaussian Mixture-based (MOG2) Video Coding for CCTVs. The aim of this paper is to optimize the MOG2 algorithm used for foreground-background separation in video streaming. In fact, our previous study showed that traditional video encoding with the help of MOG2 has a negative effect on visual quality. Therefore, this study is our main motivation for improving visual quality by combining the previously proposed algorithm and color optimization method to achieve better visual quality. In this regard, we introduce Artificial Intelligence (AI) video encoding using Color Clustering (CC), which is used before the MOG2 process to optimize color and make a less noisy mask. The results of our experiments show that with this method the visual quality is significantly increased, while the latency remains almost the same. Consequently, instead of using morphological transformation which has been used in our past study, CC achieves better results such that PSNR and SSIM values have been shown to rise by approximately 1dB and 1 unit respectively.
Telecommunications
Amir Hatamian; Farzad Farshidi; Changiz Ghobadi; Javad Nourinia; Ehsan Mostafapour
Abstract
The increasing risk of cardiovascular diseases, stress, high blood pressure, obesity, sleep disorders and depression causes the electrocardiogram (ECG) monitors are used for diagnosing health. The main objective of this research is to enhance the quality of the ECG signal using wavelet transform and ...
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The increasing risk of cardiovascular diseases, stress, high blood pressure, obesity, sleep disorders and depression causes the electrocardiogram (ECG) monitors are used for diagnosing health. The main objective of this research is to enhance the quality of the ECG signal using wavelet transform and adaptive filters. This research has been made as descriptive-analytic and the method is used in the signal processing stages to calculate the ECG modulation spectrum, the spectral-modulation filtering scheme and as well as the ECG database from the standard algorithm and performance criteria. The results of the simulation indicate that the conversion of Sym4 and the adaptive filter with the size of 0.0005 and the length of the filter of 25 signals to the noise will be greatly improved to reveal the main features of the ECG signal.
Power
Mohammad Afkar; Parham Karimi; Roghayeh Gavagsaz-Ghoachani; Matheepot Phattanasak; Serge Pierfederici
Abstract
In fuel cell systems, voltage balancing is an important consideration. The utilization of a modular construction based on a three-level boost converter was able to balance DC voltage. This paper investigates the effect of parameter variations, such as inductors and capacitors, on the converter's steady-state ...
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In fuel cell systems, voltage balancing is an important consideration. The utilization of a modular construction based on a three-level boost converter was able to balance DC voltage. This paper investigates the effect of parameter variations, such as inductors and capacitors, on the converter's steady-state controllable areas. The plot of the inductor current and the voltages of the output capacitors are illustrated for different scenarios. The system simulation results were performed using MATLAB / Simulink software.