Brain Inspired Algorithms Dr. David Fagan Neurocomputing Brain Inspired Algorithms Dr. David Fagan MIS40980 Natural Computing & Applications

Basic Unit of the Computer In computers we use transistors to perform computation Once enough voltage is applied to the base, the connection between collector and emitter is established. Foundation of all processors in computers. MIS40980 Natural Computing & Applications

MIS40980 Natural Computing & Applications Basic Unit of the Brain MIS40980 Natural Computing & Applications

MIS40980 Natural Computing & Applications Human Brain Extremely complex computational device Estimated 80 – 100 billion nerve cells in human brain It takes 82,944 processors running a network of 1.73 billion cells with 10.4 trillion synapses 40 minutes to perform 1 second of brain processing time. Using 1PB (1,000,000 GB) of memory!!!!! More here MIS40980 Natural Computing & Applications

MIS40980 Natural Computing & Applications Neural Networks Neural Networks cover a wide variety of algorithms that take inspiration from the brain. Key to all these networks is a general model of a Neuron (Perceptron) MIS40980 Natural Computing & Applications

MIS40980 Natural Computing & Applications Basic Neural Network A neural network is essentially: A composition of Perceptrons Connected in different ways Operating on different activation functions. Glosser.ca MIS40980 Natural Computing & Applications

MIS40980 Natural Computing & Applications Neural Networks Neurons Bias Training Network Types MIS40980 Natural Computing & Applications

MIS40980 Natural Computing & Applications Neurons Many different activation functions Each one has different characteristics http://engineeronadisk.com/ MIS40980 Natural Computing & Applications

MIS40980 Natural Computing & Applications Bias Bias is a constant that is added to a layer, the value of which can be adjusted during training Bias allows the network to shift the activation function, potentially allowing for better fitting of the neuron to the data, which may be critical for successful learning. In most cases bias is helpful MIS40980 Natural Computing & Applications

MIS40980 Natural Computing & Applications Bias http://stackoverflow.com/questions/2480650/role-of-bias-in-neural-networks MIS40980 Natural Computing & Applications

MIS40980 Natural Computing & Applications Bias http://stackoverflow.com/questions/2480650/role-of-bias-in-neural-networks MIS40980 Natural Computing & Applications

MIS40980 Natural Computing & Applications Training Getting a network to learn can be extremely difficult and slow. Several approaches to training neural nets exist. The most prevalent is Back propagation of Errors This is used with some form of optimization method like gradient decent MIS40980 Natural Computing & Applications

MIS40980 Natural Computing & Applications Training In Matlab they offer the following: Levenberg-Marquardt BFGS Quasi-Newton Resilient Backpropagation Scaled Conjugate Gradient Conjugate Gradient with Powell/Beale Restarts Fletcher-Powell Conjugate Gradient Polak-Ribiére Conjugate Gradient One Step Secant Variable Learning Rate Backpropagation Click here for more info MIS40980 Natural Computing & Applications

MIS40980 Natural Computing & Applications Learning Methods Supervised Learning Pattern Recognition, Classification), Regression, Speech and Gesture recognition. Learning with a Teacher Unsupervised Learning Clustering, Estimation of Statistical Distributions, Compression and Filtering. Some data is given and a cost function is used to drive the learning. Reinforcement Learning Control Problems, Games and Sequential Decision Making Tasks. Learn by minimising / maximising gain with each interaction with environment MIS40980 Natural Computing & Applications

MIS40980 Natural Computing & Applications Network Types Feed Forward NN Auto Encoder Recurrent Neural Nets Restricted Boltzmann Machine Many more…........... Google is your friend here!!!!!!! or click here All based on similar fundamental MIS40980 Natural Computing & Applications

Software for Neural Nets Many Libraries Exist For beginners I generally recommend PyBrain Python based, easy to install and loads of documentation Many more to pick from Theano, Caffe, TensorFlow, PyTorch............ Give TensorFlow or PyTorch a go!!!! MIS40980 Natural Computing & Applications

MIS40980 Natural Computing & Applications Lets Play!!!!!! The following is an interactive web based neural network that helps to show how networks behave during training Tensor Flow Playground MIS40980 Natural Computing & Applications

MIS40980 Natural Computing & Applications Deep Neural Networks In the past it was difficult to train large networks (time, computation, hardware) Recent advances (GPU acceleration, large computational clusters etc.) have allowed for easier training of networks Deep Networks simply refers to any network that has many layers (5+ layers) Modern Deep Nets have many layers and take months/years to train Deep Nets and Deep Learning are two different things!!!!!! MIS40980 Natural Computing & Applications

MIS40980 Natural Computing & Applications Deep Nets Source MIS40980 Natural Computing & Applications

MIS40980 Natural Computing & Applications Deep Nets Source MIS40980 Natural Computing & Applications

MIS40980 Natural Computing & Applications Deep Nets Source MIS40980 Natural Computing & Applications

Deep Neural Networks in the News Google Deepmind – AlphaGo Go is a very difficult game for computer In January 2016 both Google and Facebook released results for there respective GO AI projects, indicating both were reaching levels never reached by previous AI’s Google’s results where from Oct/Nov 2015 In March 2016 AlphaGo played 5 games against top human player Lee Sedol AlphaGo only lost one game after it made a mistake but took several moves to realise this mistake at which point the game was beyond saving Google had been training the AI against itself from Oct/Nov till March Recently beat he world #1 ranked go player!!!!!!!! MIS40980 Natural Computing & Applications

Deep Learning Examples Check out this page that contains Deep ConvNets that run in your browser ConvNetsJS MIS40980 Natural Computing & Applications

Machine learning and Deep Neural Nets Still confused? Check out this video Loads of courses and instructional videos available on Youtube Same goes for online courses, just ask Google MIS40980 Natural Computing & Applications

MIS40980 Natural Computing & Applications Evolution + NN NEAT Evolution of Neural Networks using a GA to decide structure and weights etc. Several version with most recent being HyperNEAT MIS40980 Natural Computing & Applications