146,077 research outputs found

    Optimal Parameter Extraction Scheme of Current Sources and Bias Dependent Elements for HBT by searching the whole unknown Parameter Space

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    New analytical expressions for the dynamic resistance,transconductance,base-collector internal capacitance,and base-emitter internal capacitance are derived.And a new scheme,to extract the current source parameters,thermal parameter,and small signal parameters at multiple bias points on the normal active region,is developed.The proposed parameter extraction method is robust and very fast.Based on these equations, we propose a new scheme to find out the optimal solution by searching for a full-unknown parameter space.The search space corresponds to 1.17x10 8 points on the error surface, and it takes 12.6 hours to get an optimal model parameters using a 2GHz-desktop PC.This scheme is helpful for the modeling of HBT excluding the local minimum problem in the gradient optimization method and the inaccuracies in the direct extraction method

    Different Techniques and Algorithms for Biomedical Signal Processing

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    This paper is intended to give a broad overview of the complex area of biomedical and their use in signal processing. It contains sufficient theoretical materials to provide some understanding of the techniques involved for the researcher in the field. This paper consists of two parts: feature extraction and pattern recognition. The first part provides a basic understanding as to how the time domain signal of patient are converted to the frequency domain for analysis. The second part provides basic for understanding the theoretical and practical approaches to the development of neural network models and their implementation in modeling biological syste

    Inferring models of bacterial dynamics toward point sources

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    Experiments have shown that bacteria can be sensitive to small variations in chemoattractant (CA) concentrations. Motivated by these findings, our focus here is on a regime rarely studied in experiments: bacteria tracking point CA sources (such as food patches or even prey). In tracking point sources, the CA detected by bacteria may show very large spatiotemporal fluctuations which vary with distance from the source. We present a general statistical model to describe how bacteria locate point sources of food on the basis of stochastic event detection, rather than CA gradient information. We show how all model parameters can be directly inferred from single cell tracking data even in the limit of high detection noise. Once parameterized, our model recapitulates bacterial behavior around point sources such as the "volcano effect". In addition, while the search by bacteria for point sources such as prey may appear random, our model identifies key statistical signatures of a targeted search for a point source given any arbitrary source configuration

    Seqgan: sequence generative adversarial nets with policy gradient

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    As a new way of training generative models, Generative Adversarial Net (GAN) that uses a discriminative model to guide the training of the generative model has enjoyed considerable success in generating real-valued data. However, it has limitations when the goal is for generating sequences of discrete tokens. A major reason lies in that the discrete outputs from the generative model make it difficult to pass the gradient update from the discriminative model to the generative model. Also, the discriminative model can only assess a complete sequence, while for a partially generated sequence, it is nontrivial to balance its current score and the future one once the entire sequence has been generated. In this paper, we propose a sequence generation framework, called SeqGAN, to solve the problems. Modeling the data generator as a stochastic policy in reinforcement learning (RL), SeqGAN bypasses the generator differentiation problem by directly performing gradient policy update. The RL reward signal comes from the GAN discriminator judged on a complete sequence, and is passed back to the intermediate state-action steps using Monte Carlo search. Extensive experiments on synthetic data and real-world tasks demonstrate significant improvements over strong baselines
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