# BSM-Data Reuse Model Based on In-Vehicular Computing
## 4 BSM Reuse Model: Our Proposal
### Architecture Design
#### 4.4.2 Data Maintain and Processing  
Maintaining the captured BSM is the main task in our approach focused on preparing data for analysis and further reuse. It refers to data storage, modeling, reduction, and aggregation. A Data storage and modeling: Messages, Frames, or Elements? After capturing the raw data, there is a requirement to transmit the data to suitable in-vehicle data storage systems for further processing and reuse. Accordingly, consideration should be given to how data are stored. Referring to the data is received as messages. The messages contain frames and the frames contain data elements. Connected vehicles and other related system functions usually require the use of data elements, but each element needs a location in time to make it useful. * Messages: storing the data as messages would demand any future use of this information to inquire and access data elements across multiple messages. Furthermore, these messages will contain multiple elements that are not used by the function and may accordingly be inefficient to be accessed, used, and/or transmitted. * Frames: to store the data as frames alone would not suffice, since many of the data elements are not necessarily in a frame. * Element: if data are stored as elements alone, then any information concerning the association between data elements is lost. For example, if a BSM is divided into its elements, relationships between windshield wipers activation and temperature in a particular vehicle would not be known. However, such associations between data contained in messages generated by an individual vehicle can be generally accommodated by using the temporary ID assigned to messages sets to associate data for access or use. Because the association between data with one vehicle can be accommodated, it may be beneficial to store the data as elements. Overall, storing BSMs as elements that are associated with each other would allow each function or request to obtain information to only access the data elements it requires. Accordingly, we propose the relationship modelization that is shown in Figure 7. This approach allows for elements of the same type from different messages to be grouped together. For example, if the vehicle is responding to an inquiry from other connected vehicle requesting weather data, it would be able to read elements such as temperature and  
Figure 6: The basic architectural concept of Request-To-Receive approach. windshield wiper activations from a single query, even though the data had been retrieved from multiple messages. * Data reduction: data reduction is responsible for decreasing data storage requirements and communications bandwidth. A range of data reduction techniques may be appropriate to allow our model to minimize data storage requirements and communications bandwidth. * Compression: BSMZip (lossless compression for basic safety messages) Multiple compression techniques, including both lossy and lossless, could be applied to connected vehicle data. Lossless compression ensures data integrity and is more suitable for BSMs data. In our model, we consider the application of run-length encoding (RLE) on a stream of BSM data. To the best of our knowledge, it has not been applied yet for data handling in the automotive domain. * Aggregation: different data aggregation strategies are appropriate to allow our model to perform a wide range of data processing, summarization, and display. Our model contains complicated aggregations on particular data elements, geo-fences, and some parameters for particular routes and areas of interest for end-users. Some of the connected vehicle applications may need to adopt a geo-fencing technique to help with limiting the data to be exchanged. This aforementioned technique defines an area of interest by drawing a boundary on BSMs, inside this defined area, specific data processing function can be accomplished. For instance, a speed detector on a highway may be a rectangle covering all lanes, in which any BSMs may have this speed qualified for further processing.