Downloaded from https://www.everyspec.com ADS-79D-HDBK Data Reduction. Data Reduction refers to any action taken to reduce the volume of the measured data without compromising the value of the data with regard to its intended purpose. Data reduction is often performed as part of the acquisition process in order to reduce the burden on storage capacity and may be broadly interpreted to actions ranging from down sampling (volume reduction) to filtering (smoothing). Data Reliability. Data Reliability refers to the provisions taken so the data can be used for its purposes in the CBM system as a result of steps taken to ensure its integrity and availability.
Data that the end user receives must be consistent with its origination. Data Security. Data Security refers to the provisions taken to ensure that the data is protected from corruption by malicious acts, unauthorized access, or accidental mishandling. Data Verification. Data Verification refers to the steps taken to confirm the integrity of data retrieved from a storage system. These techniques include the use of hash functions on data read-back or the use of a Message Integrity Code (MIC0) or Message Authentication Code (MAC). End-to-End.
This term is used within the context of this appendix to mean encompassing the mechanisms from the point at which the data is collected (acquired) to the point in which the data is destroyed including transmission, computation, storage, retrieval, and disposal. L.4 GENERAL GUIDANCE CBM systems require the processing and storage of digital data in both aircraft onboard and ground station systems. This data is used to make often critical maintenance decisions regarding the airworthiness and remaining useful life (RUL) of the vehicle, its subsystems, assemblies, or components and therefore, should be trustworthy.
This appendix describes the system end-to-end design practices to be used to ensure the integrity, reliability, and security of CBM flight data from its onboard acquisition to its ground station storage and usage. Precautions should be taken at each stage of a CBM system implementation as data integrity can be compromised at any point in the chain from acquisition to storage and retrieval for use. Corruption and loss of data may occur during: a. Acquisition b. Onboard computation c. Transmission d. Storage e.
Retrieval and use In addition, the loss of data integrity may be either inadvertent or the result of willful malicious attacks and, therefore, care and handling should include prudent practices that guard against both forms of corruption and loss. 226