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Snapshots in Real-Time Database using Database Pointer Transactions
Mälardalen University, Department of Computer Science and Electronics.ORCID iD: 0000-0003-2898-9570
2005 (English)In: Proceedings - 11th IEEE International Conference on Embedded and Real-Time Computing Systems and Applications, 2005, 343-349 p.Conference paper, Published paper (Other academic)
Abstract [en]

We present 2V-DBP-SNAP an algorithm that allows hard real-time tasks in an embedded real-time control system to read a snapshot of a number of data elements in a real-time database. Furthermore, 2V-DBP-SNAP allows these data elements to be shared with soft real-time tasks, which access them using a database query language, and with other hard real-time tasks that use database pointers. 2V-DBP-SNAP allows temporal behavior and memory consumption to be accurately predicted. Introducing snapshot transactions is beneficial for embedded control-systems, such as for engine control in an automotive system, since a snapshot of the state of the environment can be collected, e.g., the state of all cylinders in the engine. 2V-DBP-SNAP is lightweight and predictable, both with respect to computational and memory overhead, and is therefore highly suited for resource constrained systems.

Place, publisher, year, edition, pages
2005. 343-349 p.
National Category
Engineering and Technology
Identifiers
URN: urn:nbn:se:mdh:diva-4230DOI: 10.1109/RTCSA.2005.95ISI: 000235157400057Scopus ID: 2-s2.0-33749046063ISBN: 9780769523460 (print)OAI: oai:DiVA.org:mdh-4230DiVA: diva2:121281
Conference
11th IEEE International Conference on Embedded and Real-Time Computing Systems and Applications; Hong Kong; China; 17 August 2005 through 19 August 2005
Available from: 2005-11-24 Created: 2005-11-24 Last updated: 2016-02-25Bibliographically approved
In thesis
1. Data Management in Vehicle Control-Systems
Open this publication in new window or tab >>Data Management in Vehicle Control-Systems
2005 (English)Doctoral thesis, comprehensive summary (Other scientific)
Abstract [en]

As the complexity of vehicle control-systems increases, the amount of information that these systems are intended to handle also increases. This thesis provides concepts relating to real-time database management systems to be used in such control-systems. By integrating a real-time database management system into a vehicle control-system, data management on a higher level of abstraction can be achieved. Current database management concepts are not sufficient for use in vehicles, and new concepts are necessary. A case-study at Volvo Construction Equipment Components AB in Eskilstuna, Sweden presented in this thesis, together with a survey of existing database platforms confirms this. The thesis specifically addresses data access issues by introducing; (i) a data access method, denoted database pointers, which enables data in a real-time database management system to be accessed efficiently. Database pointers, which resemble regular pointers variables, permit individual data elements in the database to be directly pointed out, without risking a violation of the database integrity. (ii) two concurrency-control algorithms, denoted 2V-DBP and 2V-DBP-SNAP which enable critical (hard real-time) and non-critical (soft real-time) data accesses to co-exist, without blocking of the hard real-time data accesses or risking unnecessary abortions of soft real-time data accesses. The thesis shows that 2V-DBP significantly outperforms a standard real-time concurrency control algorithm both with respect to lower response-times and minimized abortions. (iii) two concepts, denoted substitution and subscription queries that enable service- and diagnostics-tools to stimulate and monitor a control-system during run-time. The concepts presented in this thesis form a basis on which a data management concept suitable for embedded real-time systems, such as vehicle control-systems, can be built.

Abstract [sv]

Ett modernt fordon är idag i princip helt styrt av inbyggda datorer. I takt med att funktionaliteten i fordonen ökar, blir programvaran i dessa datorer mer och mer komplex. Komplex programvara är svår och kostsam att konstruera. För att hantera denna komplexitet och underlätta konstruktion, satsar nu industrin på att finna metoder för att konstruera dessa system på en högre abstraktionsnivå. Dessa metoder syftar till att strukturera programvaran idess olika funktionella beståndsdelar, till exempel genom att använda så kallad komponentbaserad programvaruutveckling. Men, dessa metoder är inte effektiva vad gäller att hantera den ökande mängden information som följer med den ökande funktionaliteten i systemen. Exempel på information som skall hanteras är data från sensorer utspridda i bilen (temperaturer, tryck, varvtal osv.), styrdata från föraren (t.ex. rattutslag och gaspådrag), parameterdata, och loggdata som används för servicediagnostik. Denna information kan klassas som säkerhetskritisk eftersom den används för att styra beteendet av fordonet. På senare tid har dock mängden icke säkerhetskritisk information ökat, exempelvis i bekvämlighetssystem som multimedia-, navigations- och passagerarergonomisystem.

Denna avhandling syftar till att visa hur ett datahanteringssystem för inbyggda system, till exempel fordonssystem, kan konstrueras. Genom att använda ett realtidsdatabashanteringssystem för att lyfta upp datahanteringen på en högre abstraktionsnivå kan fordonssystem tillåtas att hantera stora mängder information på ett mycket enklare sätt än i nuvarande system. Ett sådant datahanteringssystem ger systemarkitekterna möjlighet att strukturera och modellera informationen på ett logiskt och överblickbart sätt. Informationen kan sedan läsas och uppdateras genom standardiserade gränssnitt anpassade förolika typer av funktionalitet. Avhandlingen behandlar specifikt problemet hur information i databasen, med hjälp av en concurrency-control algoritm, skall kunna delas av både säkerhetskritiska och icke säkerhetskritiska systemfunktioner i fordonet. Vidare avhandlas hur information kan distribueras både mellan olika datorsystem i fordonet, men också till diagnostik- och serviceverktyg som kan kopplas in i fordonet.

Publisher
54 p.
Series
Mälardalen University Press Dissertations, ISSN 1651-4238 ; 21
National Category
Computer Science
Research subject
Datavetenskap
Identifiers
urn:nbn:se:mdh:diva-66 (URN)91-88834-97-2 (ISBN)
Public defence
2005-10-26, Gamma, Västerås, 13:15
Opponent
Supervisors
Available from: 2005-11-24 Created: 2005-11-24 Last updated: 2013-12-03

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Nyström, DagNolin, MikaelNorström, Christer
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