Because lithium-ion batteries are widely used for various purposes, it is important to estimate their state of health (SOH) to ensure their efficiency and safety. Despite the usefulness of model-based methods for SOH estimation, the difficulties of battery modeling have resulted in a greater emphasis on machine learning for SOH estimation. Furthermore, data preprocessing has received much attention because it is an important step in determining the efficiency of machine learning methods. In this paper, we propose a new preprocessing method for improving the efficiency of machine learning for SOH estimation. The proposed method consists of the relative state of charge (SOC) and data processing, which transforms time-domain data into SOC-domain data. According to the correlation analysis, SOC-domain data are more correlated with the usable capacity than time-domain data. Furthermore, we compare the estimation results of SOC-based data and time-based data in feedforward neural networks (FNNs), convolutional neural networks (CNNs), and long short-term memory (LSTM). The results show that the SOC-based preprocessing outperforms conventional time-domain data-based techniques. Furthermore, the accuracy of the simplest FNN model with the proposed method is higher than that of the CNN model and the LSTM model with a conventional method when training data are small.
We propose a new process technique for fabricating very high-density trench MOSFETs using 3 mask layers with oxide spacers and a self-aligned technique. This technique reduces the device size in trench width, source, and p-body region with a resulting increase in cell density and current driving capability as well as cost-effective production capability. We were able to obtain a higher breakdown voltage with uniform oxide grown along the trench surface. The channel density of the trench DMOSFET with a cell pitch of 2.3-2.4 µm was 100 Mcell/in2 and a specific on-resistance of 0.41 mΩ·cm2 was obtained under a blocking voltage of 43 V.
We propose a speed up method for the Histograms of Oriented Gradients - Local Binary Pattern (HOG-LBP) based pedestrian detector. Our method is based on the two-stage cascade structure. In the first stage evaluation, instead of extracting the features from all the region inside the detection window like in the conventional method, we extract the features from the regions which best characterize the pedestrian only. By reducing the features to be evaluated, each candidate is evaluated faster. To determine which regions are best for characterizing the pedestrian, we train the AdaBoost classifier to select the blocks whose Support Vector Machine responses of the pedestrian samples are most different from the non-pedestrians. In the second stage, we simply use the conventional HOG-LBP classifier to reevaluate the candidates which pass the first stage evaluation. Experimental results show that the detection algorithm is about three times faster than the conventional HOG-LBP SVM algorithm.
16 November 2012 in IEEE Transactions on Circuits and Systems II: Express Briefs
This brief presents a 10-bit dual-channel pipelined flash-successive approximation register (SAR) analog-to-digital converter (ADC) for high-speed applications. The proposed ADC consists of two channels for high operating speed, and each channel adopts a pipelined flash-SAR architecture for low power and a small area. The proposed flash-SAR ADC in the second stage is composed of a 1-bit flash ADC and a 6-bit SAR ADC considering the chip area, operation speed, and circuit complexity. The prototype ADC fabricated in a 45-nm CMOS process occupies 0.16 mm2. The differential and integral nonlinearities of the ADC are less than 0.36 and 0.67 LSB, respectively. The ADC shows a signal-to-noise-and-distortion ratio of 54.6 dB and a spurious-free dynamic range of 64.0 dB with a 78-MHz input at 230 MS/s with a 1.1-V supply. The maximum operating frequency of the ADC is 260 MS/s at a 1.2-V supply. The power consumptions of the ADC with 230 and 260 MS/s are 13.9 and 17.8 mW, respectively.
A novel simplified fabrication method of a very high density p-channel trench gate power MOSFET using four mask layers and nitride/TEOS sidewall spacers is realized. The proposed process showed improved on-resistance characteristics of the device with increasing cell density and the cost-effective production capability due to the lesser number of processing steps. By using this process technique, a remarkably increased high density (100 Mcell/inch/sup 2/) trench gate power MOSFET with a cell pitch of 2.5 /spl mu/m could be effectively realized. The fabricated device had a low specific on-resistance of 1.1 m/spl Omega/-cm/sup 2/ with a breakdown voltage of -36 V.