A neuron is a mathematical function that takes one or more values as input and outputs a ingle numerical value −It can be defined as follows −Here, ‘f’ refers to the function.We first computed the weighted sum of the inputs xi and the weights wiThe weight wi is also known as the activation value or activation function.The input xi can be a numerical value that represents the input data or it can be an output from other neurons if the neuron belong to a neural network.The weight wi is a numerical value that can be used to represent the strength ... Read More

A neural network can be understood as a network of hidden layers, an input layer and an output layer that tries to mimic the working of a human brain.The hidden layers can be visualized as an abstract representation of the input data itself. These layers help the neural network understand various features of the data with the help of its own internal logic.These neural networks are non-interpretable models. Non-interpretable models are those which can’t be interpreted or understood even if we observe the hidden layers. This is because the neural networks have an internal logic working on its own, that ... Read More

The basic example of a neural network is a ‘perceptron’. It was invented by Frank Rosenblatt in 1957. The perceptron is a classification algorithm similar to logistic regression. This because, similar to logistic regression, a perceptron has weights, w, and an output function, ‘f’, which is a dot product of the weights and the input.The only difference is that ‘f’ is a simple step function, where a logistic regression rule is applied to the output of the logistic function. On the other hand, perceptron can be understood as an example of a simple one-layer neural feedforward network.The perceptron was considered ... Read More

Neural networks have been around for many years, through which they have been praised as well as criticised for their characteristics.But off late, they have gained attention over other machine learning algorithms. Of course, Machine learning algorithms are important as they help achieve certain goals. But what should we do when machine learning algorithms can’t achieve higher accuracy?This is where deep learning algorithms come into play. They mimic the layers of the human brain, and try to take optimal decisions by passing an input from one layer to the next.Neural networks, as the name suggests, tries to follow the pattern ... Read More

We previously understood how Q-learning works, with the help of Q-value and Q-table. Q-learning is a type of reinforcement learning algorithm that contains an ‘agent’ that takes actions required to reach the optimal solution. This is achieved with the help of Q-table that is present as a neural network. It helps take the right step that maximizes the reward, thereby reaching the optimal solution.Now, let us see how the agent uses the policy to decide on the next step that it needs to take to achieve optimum results.The policy considers the Q-values of all possible actions that could be taken, ... Read More

Q-learning is a type of reinforcement learning algorithm that contains an ‘agent’ that takes actions required to reach the optimal solution.Reinforcement learning is a part of the ‘semi-supervised’ machine learning algorithms. When an input dataset is provided to a reinforcement learning algorithm, it learns from such a dataset, otherwise it learns from its experiences and surroundings.When the ‘reinforcement agent’ performs an action, it is awarded or punished (awards and punishments are different, as they depend on the data available in hand) based on whether it predicted correctly (or took the right path or took a path that was least expensive).If ... Read More

Problem:You want to display open cursors in Oracle.SolutionWe can query the data dictionary to determine the number of cursors that are open per session. "V$SESSION" provides a more accurate number of the cursors currently open than "V$OPEN_CURSOR".Exampleselect  a.value  , c.username  , c.machine  , c.sid  , c.serial# from v$sesstat a  , v$statname b  , v$session c where a.statistic# = b.statistic# and c.sid  = a.sid and b.name  = 'opened cursors current' and a.value  != 0 and c.username IS NOT NULL order by 1, 2;The OPEN_CURSORS initialization parameter determines the maximum number of cursors a session can have open.Read More

Problem:You want to identify the SQL statements consuming more resources in Oracle.Solution“V$SQLSTATS" view displays performance statistics for SQL statements that have recently executed. You can also use "V$SQL” and “V$SQLAREA" to report on SQL resource usage. "V$SQLSTATS” is faster and retains information for a longer period of time, but contains only a subset of the columns in “V$SQL" and "V$SQLAREA”.Exampleselect * from( select   sql_text  ,buffer_gets  ,disk_reads  ,sorts  ,cpu_time/1000000 cpu_sec  ,executions  ,rows_processed from v$sqlstats order by cpu_time DESC) where rownum < 20;

Problem:You want to view where Oracle SQL is taking time within a SQL execution plan.SolutionWith Oracle 11g version, we can view SQL execution plan progress while the SQL is running. The “V$SQL_PLAN_MONITOR” view contains a row for each step of a SQL statement’s execution plan. Below SQL will help to view the execution plan along with the progress.The “V$SQL_PLAN_MONITOR" provides you with information on the steps that are using the most resources. The statistics in "V$SQL_PLAN_MONITOR” are updated every second.We can also generate a real time text, HTML, or even a XML report of query progress within an execution plan ... Read More

Problem:You want to know how much longer a long running SQL might ake to finish.SolutionWe can use “V$SESSION_LONGOPS" view to know the approximate time of a query left to execute. "V$SESSION_LONGOPS” view displays the status of various database operations that have been running for longer than six seconds. Please note that this view give you only a rough estimate of when a SQL might complete.Exampleselect   a.username  , a.opname  , b.sql_text  , to_char(a.start_time, 'DD-MON-YY HH24:MI') start_time  , a.elapsed_seconds how_long  , a.time_remaining secs_left  , a.sofar  , a.totalwork  , round(a.sofar/a.totalwork*100, 2) percent from v$session_longops a     ,v$sql         ... Read More