Aggregate overview

Welcome

Aggregate is designed to help you pre-process your data for more advanced signal analysis.

Getting Started

Watch this quick demo showing how data is processed using the aggregate module.

Home interface

ControlFunction
File open. Use this button to navigate to your data folder. Once you have selected a data file it will automatically load. Alternatively you can load a file by dragging the file directly into the box.
This may take several minutes if your files are stored as large .txt or .csv files*. Native files opened using data plugins should display within second regardless of file size.*If you are attempting to open large files (>100MB) we recommend either pre-truncating your data or using the 64-bit version of Ensemble. If you’re using an Emulator please ensure sufficient processor and memory resources have been allocated to the virtual machine.
File openerSelects the protocol for opening files.

Options are:

  1. Dataplugin (default): This is a tool that opens a variety of formats. Check this list for the latest supported formats.Text: Use this option for .txt files with the data structured as a table where a) each column corresponds to a signal (multiple columns if you have multiple signals) and b) along each column conseuctive numbers represent equidistantly sample data points.

  2. Text (Comments): Use this option for .txt files with annotations (data comments, labels). To display correctly all annotations must be entered along the last column, corresponding to the correct row (corresponding to the time stamp).

  3. Philips RDE: Use this to open files exported from Philips Clinical monitoring systems using the RDE toolkit.

Sampling frequency (Hz)Sets the sampling frequency in Hertz. This must be correctly specified in order to accurately detect signal features. Default is 1000 Hz.
Decimation factorDecimation is commonly used to reduced the sampling rate of a signal in order to reduce the memory and computational cost of processing the data. For example, data sampled originally at 1000 Hz will be reduced to 250 Hz if the decimation is 4. The decimation factor must be greater than zero. The default is 4.
No of channel groupsCertain file formats can store data from multiple recording sessions. The data from the channels recorded during a session is called a channel group. This indicator displays the total number of channel groups.
This feature is active only for files opened using Dataplugin.
Channel groupSelects the channel group to load into memory for analysis.
This feature is active only for files opened using Dataplugin.
Preview channelSelects the channel within channel group to load into the data preview window.
Current moduleIndicates the active analysis module during run-time.
Launches the help page.

Signal processing modules

ModulesFunction
ImportLoads data into memory.
ECGExtraction of ECG features for heart rate, heart rate variability, and baroreflex sensitivity analysis.
BP/DopplerExtracts the systolic, diastolic, and mean values from pulsatile waveform signals such as blood pressure and blood velocity.

This function requires a gating signal. The most accurate way to gate cardiac activity is the ECG.

If you do not have an ECG signal you may consider gating according to blood pressure, or some other pulsatile signal by analysing the signal using the ECG module. However, these approaches are less accurate and we do not recommended it for heart rate variability analysis.
GasesExtracts end-tidal and inspired gas concentrations from respiratory gas analyser signals.
VentilationExtracts tidal volume, minute ventilation, and respiratory rate from spirometry signals. This module is currently under development.
SaveSaves the extracted features to disk as a .TDMS file.
Click Original filename to save your file with the original name to the root folder under the folder ‘Extracted’.

To specify a custom filename click

The exact location of your saved file should be displayed in the save window.
Data labelsDisplays data annotations (if present).
Data previewLow resolution preview of the selected data channels.

Processing ECG signals

Many cardiovascular analysis techniques are performed on a ‘beat-to-beat’ basis. This requires accurate defining of the cardiac cycle and is most accurately done using the ECG.