Partitioned Vehicle Event Data Recording for Fast Retrieval
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for recording event data in highly-automated vehicles face inefficiencies due to the random sequencing of data frames, leading to unnecessary sorting and non-uniform execution times, especially when most trips do not involve events requiring persistent storage in non-volatile memory.
Innovation Solution
A method and device that utilize temporally randomly-sorted subsequences within data partitions to manage and store event data, allowing for efficient storage in volatile memory until a predetermined event occurs, and then persistently in non-volatile memory, using a buffer block to handle data frames in any time sequence and mark subsequences for quick retrieval.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If data frames are sorted by time sequence, then data retrieval efficiency is improved, but processing time increases and execution becomes non-uniform
Solution Approach 1:
The patent divides the data storage into partitions and uses a circular buffer structure where data frames are written sequentially without sorting. The buffer is segmented into fixed-size slots that wrap around, allowing efficient time-based retrieval through pointer arithmetic rather than sorting operations.
Solution Approach 2:
The system pre-allocates buffer slots and establishes write/read pointers before data arrival. By preparing the buffer structure in advance with known dimensions and access patterns, the system eliminates the need for dynamic sorting operations during data retrieval, ensuring uniform execution time.
2Loss of time
If data frames are stored in random order, then processing time is reduced, but data retrieval becomes inefficient
Solution Approach 1:
The patent introduces a circular buffer as an intermediary data structure between data arrival and retrieval operations. This buffer mediates between the random arrival order of data frames and the time-sequential retrieval requirements, using write and read pointers to maintain temporal order without actual sorting.
Solution Approach 2:
The system changes the access pattern parameters by using modular arithmetic for circular buffer indexing. Instead of sorting data by time, the system retrieves data by calculating buffer indices using (write_position + offset) mod buffer_size, transforming the retrieval problem into a constant-time mathematical operation.
3Stability of the object's composition
If sorting techniques are expanded to handle random data sequences, then data frame ordering is improved, but execution time becomes non-uniform and increases
Solution Approach 1:
Instead of sorting data frames to achieve temporal order, the patent inverts the approach by using a fixed-size circular buffer with sequential write positions. The temporal order is naturally preserved through the buffer's structure and pointer management, eliminating the need for sorting algorithms entirely.
Data Source
AI summary
A method for recording event data in a vehicle. Vehicle data are received continuously from at least one vehicle system and are written as event data in data frames of a predetermined size. The individual data frames are stored in at least one volatile memory. The stored data frames are managed and kept available in the at least one volatile memory until the event data stored in the individual data frames are older than a predetermined maximum pre-event point in time, or are stored persistently in at least one non-volatile memory in reaction to a recognized predetermined event. At least one partition of a predetermined size is provided, into which the received reference information of the individual data frames is written in any time sequence. Temporally randomly-sorted subsequences of the written reference information of the individual data frames in the at least one partition are ascertained and marked.