Risk II (aka 冒险2), a really nice strategy game sold in 2000 for Windows, is available and ready to be played again! Time to play a board / party game, turn-based and licensed title video game title. Risk 2 is the ultimate form of this world-domination game that people of all ages have enjoyed for 40 years. When it comes to computer versions of board games, you'll almost always get a compromise. Risk ii game.
Your eyes, fingers and now even your smartphone may be able to help you spot card skimmers at gas pumps and ATMs, but nothing is foolproof. “Some of the newer skimmers are almost impossible to see, even if you know what you’re looking for,” says David Tente, U.S. Executive director of the ATM Industry Association.
The lower the loss, the better a model (unless the model has over-fitted to the training data). The loss is calculated on training and validation and its interperation is how well the model is doing for these two sets. Unlike accuracy, loss is not a percentage. It is a summation of the errors made for each example in training or validation sets.In the case of neural networks, the loss is usually and for classification and regression respectively. Then naturally, the main objective in a learning model is to reduce (minimize) the loss function's value with respect to the model's parameters by changing the weight vector values through different optimization methods, such as backpropagation in neural networks.Loss value implies how well or poorly a certain model behaves after each iteration of optimization.
Ideally, one would expect the reduction of loss after each, or several, iteration(s).The accuracy of a model is usually determined after the model parameters are learned and fixed and no learning is taking place. Then the test samples are fed to the model and the number of mistakes (zero-one loss) the model makes are recorded, after comparison to the true targets. Then the percentage of misclassification is calculated.For example, if the number of test samples is 1000 and model classifies 952 of those correctly, then the model's accuracy is 95.2%.There are also some subtleties while reducing the loss value. For instance, you may run into the problem of in which the model 'memorizes' the training examples and becomes kind of ineffective for the test set.
Over-fitting also occurs in cases where you do not employ a, you have a very complex model (the number of free parameters W is large) or the number of data points N is very low. @mamatv As long as the cost is decreasing you should be good to go. Although cost and accuracy normally have a inverse proportionality relationship, but you may note that accuracy is a summation of zero-one errors whereas cost is a summation of floating point numbers. Therefore, 0.001% decrease in the cost does not necessarily mean 0.001% increase in the accuracy. Increasing the accuracy is much harder when the decrement in cost is intangible (the cost is very close to a local minima)–Jan 4 '16 at 17:34. They are two different metrics to evaluate your model's performance usually being used in different phases.Loss is often used in the training process to find the 'best' parameter values for your model (e.g.
Weights in neural network). It is what you try to optimize in the training by updating weights.Accuracy is more from an applied perspective. Once you find the optimized parameters above, you use this metrics to evaluate how accurate your model's prediction is compared to the true data.Let us use a toy classification example. You want to predict gender from one's weight and height. You have 3 data, they are as follows:(0 stands for male, 1 stands for female)y1 = 0, x1w = 50kg, x2h = 160cm;y2 = 0, x2w = 60kg, x2h = 170cm;y3 = 1, x3w = 55kg, x3h = 175cm;You use a simple logistic regression model that is y = 1/(1+exp-(b1.xw+b2.xh))How do you find b1 and b2?
You define a loss first and use optimization method to minimize the loss in an iterative way by updating b1 and b2.In our example, a typical loss for this binary classification problem can be:(a minus sign should be added in front of the summation sign)We don't know what b1 and b2 should be. Let us make a random guess say b1 = 0.1 and b2 = -0.03.
Then what is our loss now?so the loss isThen you learning algorithm (e.g. Gradient descent) will find a way to update b1 and b2 to decrease the loss.What if b1=0.1 and b2=-0.03 is the final b1 and b2 (output from gradient descent), what is the accuracy now?Let's assume if yhat = 0.5, we decide our prediction is female(1). Otherwise it would be 0. Therefore, our algorithm predict y1 = 1, y2 = 1 and y3 = 1. What is our accuracy?
We make wrong prediction on y1 and y2 and make correct one on y3. So now our accuracy is 1/3 = 33.33%PS: In, back-propagation is said to be an optimization method in NN.
I think it would be treated as a way to find gradient for weights in NN. Common optimization method in NN are GradientDescent and Adam. @Aadnan Just to clarify the Training/Validation/Test data sets:The training set is used to perform the initial training of the model, initializing the weights of the neural network.The validation set is used after the neural network has been trained. It is used for tuning the network's hyperparameters, and comparing how changes to them affect the predictive accuracy of the model. Whereas the training set can be thought of as being used to build the neural network's gate weights, the validation set allows fine tuning of the parameters or architecture of the neural network model. It's useful as it allows repeatable comparison of these different parameters/architectures against the same data and networks weights, to observe how parameter/architecture changes affect the predictive power of the network.Then the test set is used only to test the predictive accuracy of the trained neural network on previously unseen data, after training and parameter/architecture selection with the training and validation data sets.
The spot exchange rate is best thought of as how much you would have to pay in one currency to buy another at this moment in time. The spot exchange rate is usually decided through the global where currency traders, institution and countries clear transactions and trades. The forex market is the largest and most liquid market in the world, with trillions of dollars changing hands daily. The most actively traded currencies are the, the —which is used in many continental European countries including Germany, France, and Italy—the British pound, the Japanese yen and the Canadian dollar. On the transaction date, the two parties involved in the transaction agree on the price, which is the number of units of currency A that will be exchanged for currency B. The parties also agree on the value of the transaction in both currencies and the settlement date.
If both currencies are to be delivered, the parties also exchange bank information. Speculators often buy and sell multiple times for the same settlement date, in which case the transactions are netted and only the gain or loss is settled. There are a number of different ways in which traders can execute a spot exchange, especially with the advent of online trading systems. The exchange can be made directly between two parties, eliminating the need for a third party. Electronic broking systems may also be used, where dealers can make their trades through an automated order matching system. Traders can also use electronic trading systems through a single or multi-bank dealing system.
Finally, trades can be made through a voice broker, or over the phone with a foreign exchange broker.