====== General task structure of temporary aberrancy detection ======
\\ {{ :results:models:general_model_of_aberrancy_detection.png?nolink |General task structure of temporary aberrancy detection}}
\\ Temporal algorithms are represented as instances of a task-decomposition method (denoted on the graph as //Temporal Aberrancy Detection//) that performs the task of detecting aberrations in the surveillance data by decomposing this task into four subtasks (ellipses): //Compute Expectation//, //Obtain Current Observation//, //Compute Test Value//, and //Evaluate Test Value//. Each of these tasks can be accomplished by one or more eligible methods (shown as boxes). For example, //Obtain Current Observation// is a straightforward step that is typically performed by querying a database. Multiple methods can be used for the //Compute Test Value// task. While some of them accomplish their task directly (primitive methods shown as dark rectangles), others can further decompose a task into subtasks and delegate subtask execution to other methods (task-decomposition methods shown as light rectangles). For example, the //Evaluate Test Value// task, which is responsible for generating alarms, can be accomplished directly by comparing an observed value to an expected value using a predefined threshold (primitive method //Binary Alarm//), or by passing the residual of such a comparison through a control chart (task-decomposition method //Residual-Based//). Some of the methods can be used for more than one task. For example, the exponentially weighted moving average (//EWMA//) method can be used as a forecasting technique or to compute test values. 

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