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NovaStar Data / NovaScore

Introduction

Data values are useful but when considered without context do not provide qualitative information about the severity of conditions corresponding to the data. NovaScore is a qualitative value that is associated with alarm triggers and stored with each data report.

NovaScore in NovaStar

As indicated in the Alarms documentation, alarm triggers are used to indicate the NovaScore, which is a qualitative numerical level indicating severity of the condition. The larger the NovaScore value, the more severe the criteria. Each point's data record is assigned a NovaScore, which can then be used for analysis, display, and decisions. If no alarm has been triggered, than a normal score of 1 is set for the data report.

Data web services provide the NovaScore with each point's data. Consequently, the NovaScore assigned to a point's data report is the most immediate indication of critical conditions. For some data such as interval data or rated time series, the meaning of NovaScore is a variation on the original. For example, interval data typically indicate the maximum NovaScore in the interval.

Data web services also allow the NovaScore to be returned as a time series independent of the scaled values, so that times series of NovaScores can be analyzed. Below is an example of a NovaScore time series being used to create a heat map to visualize events (the example shown needs to be updated to be more relevant).

novascore-heatmap

NovaScore Heatmap Example (see full-size image)

NovaScore+ (NovaScore plus)

The features discussed in this section are being evaluated for implementation.

The existing NovaStar system's design and use of NovaScore is limiting. For example, the default NovaScores typically indicate a range of 1-5 from "normal" to "severe" conditions. However, this design does not support variations in scores by data type, or use with precipitation frequency duration checks.

Consequently, a proposed enhanced NovaScore (called NovaScore+) is being evaluated. In this design the following are handled:

  • A NovaScore "group" is used to indicate that a group of NovaScores are related, but separate from other groups, for example:
    • NovaScore for precipitation levels can be defined for IDF (Intensity Duration Frequency).
    • NovaScore for water levels can be defined consistent with NWS E19 levels, or other damage level scores.
    • NovaScore for battery voltage define when batteries need to be replaced.
  • Within the group, an appropriate number of levels can be defined, with increasing numerical value indicating increasing severity.
  • The NovaScore levels can be associated with a color table for visualization, for example red being used for most critical value (although the color association for severity may vary by data type).
  • Standard NovaScore configurations and best practices can be implemented.

Issues to be resolved with enhanced NovaScores are:

  1. Enhanced NovaScores could be implemented with or without NovaStar database changes.
    1. The existing nova_score table is simple in design with only numerical score, name, and description. Adding a group might require adding additional columns and/or also adding a group table.
    2. Alternatively, the numerical identifier, which is currently a serial integer, could be allowed to have any value and an encoded integer with group could be used. For example, a NovaScore of 100001 might indicate the water level group criteria 1. Or, a more complex integer such as 1001122331 could be used with precipitation IDF values, represenging precipitation group, I, D, F, and severity values. The main uses of the values would be in defining triggers with more granularity and allowing display tools to use the group color/symbol definitions.
    3. Encoding of integers should take into account the maximum integer allowed in PostgreSQL and software, and implement best practices that can be applied for all systems.
    4. The NovaScore description could also be used to store property value such as Group=Precipitation and GroupOrder=1 to implement new functinality without changing the database. Core system functinality could remain the same; however, data displays could be enhanced to provide more relevant information to users.
  2. Would need to enhance the Administrator to allow assigning any number to a NovaScore.
  3. Would need to confirm the behavior of the core system, including:
    1. If multiple alarms are triggered for a point (for example muliple IDF criteria), does the core system assign the maximum NovaScore value to data reports?
    2. Does the use of encoded integers cause any logic issues?

Services

The following services are related to NovaScore:

  • alarmTriggers - return list of alarm triggers for point data
  • novascores - return list of severity levels associated with alarm triggers