Embedded real-time systems are currently undergoing a fundamental change. Traditionally these systems have been developed as closed monolithic system with limited interaction with other embedded systems. But recent advances in communications, such as global mobile telecommunication Internet services, have led to that embedded real-time (RT) systems are becoming increasingly interconnected. Thus, these systems are growing more and more complex, and the amount of information that needs to be managed is also rapidly increasing. Therefore, the need for proper RT data management solutions is urgent. System engineers are already faced with difficulties with respect to data aggregation and observability where data can be analysed and acted upon directly during run-time instead of afterwards using off- line tools.
The introduction of database (DB) management systems within RT systems poses an additional challenge since DB transactions not only need to be logically consistent but also temporally consistent (i.e. they have to guarantee timeliness), i.e., DB data must be fresh and transactions must meet their deadlines. To guarantee timeliness, RT transaction models most often relax logical consistency (i.e., by relaxing ACID properties), e.g., by allowing transactions to read uncommitted data or to commit data that is in conflict with some other transaction. Concerning relaxation of I (Isolation), for instance, several notions have been explored and a plethora of RT concurrency- control algorithms has been presented over the years to offer design solutions for those new notions. However, most of these approaches assume a “one size fits all” approach and thus they do not offer the needed flexibility to address different types of transactions.
In this project, we propose a formal approach where we use product-line methods to engineer a flexible transaction model and the corresponding transaction engine adequate with respect to the temporal and logical consistency requirements. Our approach consists in the creation of a formal model of the behavior of the transactions in the system and in the application of verification and validation techniques to (i) verify that all transactions will consistently adhere to the transaction model and to the customer requirements, and (ii) identify all possible transaction conflicts not only based on the write and read set, but based on all possible interleavings of their execution. When all criteria are met, suitable conflict resolution mechanisms, such as RT DB locks, wait-free/lock-free algorithms and temporal isolation, are generated for the particular system.
Our approach enables the introduction of advanced transactions to support data aggregation and management for hard RT embedded systems with maintained predictability and a controlled relaxation of logical consistency.
|First Name||Last Name||Title|
|Dag||Nyström||Director of Education,Senior Lecturer|
Tool-Supported Design of Data Aggregation Processes in Cloud Monitoring Systems (Jan 2018) Simin Cai, Barbara Gallina, Dag Nyström, Cristina Seceleanu, Alf Larsson Journal of Ambient Intelligence and Humanized Computing (JAIHC)
Customized Real-Time Data Management for Automotive Systems: A Case Study (Oct 2017) Simin Cai, Barbara Gallina, Dag Nyström, Cristina Seceleanu 43rd Annual Conference of the IEEE Industrial Electronics Society (IECON 2017)
DAGGTAX: A Taxonomy of Data Aggregation Processes (Oct 2017) Simin Cai, Barbara Gallina, Dag Nyström, Cristina Seceleanu 7th International Conference on Model and Data Engineering (MEDI 2017)
Design of Cloud Monitoring Systems via DAGGTAX: a Case Study (May 2017) Simin Cai, Barbara Gallina, Dag Nyström, Cristina Seceleanu, Alf Larsson The 8th International Conference on Ambient Systems, Networks and Technologies (ANT 2017)
A Formal Approach for Flexible Modeling and Analysis of Transaction Timeliness and Isolation (Oct 2016) Simin Cai, Barbara Gallina, Dag Nyström, Cristina Seceleanu 24th International Conference on Real-Time Networks and Systems (RTNS'16)