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Lifecycle

This section serves as an overview of TIM Forecasting methods. It will explain their main inputs, components and outputs, how they differentiate from each other and their destined usage. Three methods (types of jobs) are in play in the lifecycle of TIM forecasting: build-model, predict and rebuild-model. The following sections explore them in more detail.

Schema

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Model building

To build a reasonable model, TIM only needs training data and a configuration. Based on those, in its multi-situational layer TIM recognizes all situations requiring a seperate model. Then, for all of these situations, the model building is done on in-sample rows, and in-sample, out-of-sample and production forecasts are calculated. Thus, the main outputs of the build-model are those forecasts and the Model Zoo.

The optimal usage of this method is for setting up the model(s) to best fit the problem at hand. There are many available configuration parameters, so it is easy to experiment and evaluate backtesting results. Models are built from scratch, so there is a certainty that the models are as fresh as possible for all situations. Once the "optimal" Model Zoo is found, it can be used in production. The following two sections summarize how this is done.

Prediction

The production pipeline can be set up as soon as the desired Model Zoo is built. The fastest approach to do so is to use the predict method. This procedure utilizes all models included in the input Model Zoo, and attempts to apply them without building any new models or refreshing any old ones.

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Only models that are a part of the input Model Zoo are used to make a forecast. Therefore, only a short period of data is needed to interpret these models and make predictions. The exact size required is defined by the "Data from" section of the Model Zoo. Thus, the calculation time of this method is very low.

The weakness of this process is that the responsibility to make sure that the Model Zoo can produce every required forecast is on the user. TIM cannot forecast situations for which there is no model in the Model Zoo. This can happen not only when changing the prediction horizon, but also due to missing data; both situations can trigger a need to rebuild a Model Zoo. Another disadvantage is that the models tend to become "old" or outdated after some time (depending on the problem) resulting in deteriorating accuracy. These challenges can be overcome by the rebuild-model method described in the next section.

Model rebuilding

This functionality offers the best routines for handling a production deployment. It solves the challenges with new situations and deteriorating accuracy without introducing the need to build all models from scratch.

As visualized, the inputs of this method are the Model Zoo, data and a configuration. Based on those, in its multi-situational layer TIM recognizes all situations. Then model rebuilding on in-sample rows is done - based on the rebuilding policy either only for new situations or also for the situations containing old models - and in-sample forecasts (for new models), out-of-sample forecasts and production forecasts are calculated. Thus, the main outputs of the rebuild-model method are those forecasts and the updated Model Zoo. Such an updated Model Zoo can be used again as input for another predict or rebuild-model job.

Model upload

TIM allows uploading a pre-built model to a use case by creating an upload-model job. Such a job can be created either by specifying an existing job that contains a model or by uploading a model that was previously downloaded from another job. The upload-model job can upload the model to a use case that is associated with a different dataset than the one used to build the model, however, the new dataset has to be compatible with the model (identical column names, sampling rate, etc.). An upload-model job can be used as a parent job for running prediction or model rebuilding jobs.