Real-Time Databases and Data Services

Ramamritham, Krithi; Son, Sang H.; DiPippo, Lisa Cingiser

doi:10.1023/b:time.0000045317.37980.a5

Cited by 133 publications

(120 citation statements)

References 129 publications

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“…The database is assumed to be maintained in the main memory. This assumption is valid for most real-time systems for event monitoring as the number of data objects to be maintained in the databases is usually not large [25].…”

Section: System Model and Assumptionsmentioning

confidence: 99%

“…To maintain the temporal validity of a real-time data object, new data values are generated from a sensor periodically [16,20]. Once generated, the new value is sent as an update job to a real-time controller to be installed into a real-time database for refreshing the corresponding data object maintained in the database [25]. How to generate and schedule the update transactions to maintain the temporal validity of the set of real-time data objects in a real-time database has been a hot research topic and various fixed and dynamic priority scheduling algorithms have been proposed [12,32,36].…”

Section: Introductionmentioning

confidence: 99%

“…The data objects that are used to represent the current status of the dynamic entities in the operation environment, e.g., the coordinates of the posture of an old man and the body temperature of a patient, are called real-time data objects [25]. As the status of the entities could be highly dynamic, a real-time data object has a real-time constraint on its validity defined as the "life-span" of its current value.…”

Section: Introductionmentioning

confidence: 99%

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An effective fixed priority co-scheduling algorithm for periodic update and application transactions

et al. 2012

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An important function of many Cyber-Physical Systems (CPS) is to provide a close monitoring of the operation environment to be able to adapt to changing situations effectively. One of the commonly applied techniques for that is to invoke time-constrained periodic application transactions to check the status of the operation environment. The status of the environment is represented by the values of the physical entities in the operation environment which are maintained as real-time data objects in a real-time database. Unfortunately, meeting the deadlines of application transactions and maintaining the quality of real-time data objects are conflicting with each other, because they compete for the same computation resources. To address this problem of update and application transactions co-scheduling problem, in this paper, we propose a fixed priority co-scheduling algorithm called Periodic Co-Scheduling ( PCS). PCS uses periodic update transactions to maintain the temporal validity of real-time data objects. It judiciously decides the priority orders among all the update and application transactions so that the constructed schedule can satisfy the deadline constraints of all the application transactions and at the same time maximize the qualities of the real-time data objects to ensure the correct execution of application transactions. The effectiveness of the algorithm is validated through extensive simulation experiments.

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Section: System Model and Assumptionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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An effective fixed priority co-scheduling algorithm for periodic update and application transactions

et al. 2012

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“…The middleware will obviously use services offered by the fundamental operating system. Because this creates resources like files and communications ports from lower-level components, it obtains the liability for as long as ways to organize access to them [4]. Furthermore, Access control is apprehensive with shaping the permissible actions of legal users; mediate each effort by a user to access a part of data in the system [5].…”

Section: Introductionmentioning

confidence: 99%

Design of Algorithm for Environment based Dynamic Access Control Model for Database Systems

Ahmad¹,

Ahmad²

2011

IJCA

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With the fast growing nature of enterprise business especially with the emergence of information technology, we are moving towards the era where database systems have become mandatory for the organizations to implement. Because of this, it has become very important to specify such access control model for the database systems in organizations that must ensure the security of information but at the same time dynamic. Conventionally, access control models stress on pre-defined users for which access level is pre-determined by the database administrator. Considering the need of today's business, that has become borderless, and most of unknown users also attempt to access the information, we present a design algorithm for access control model that can handle for both existing and unknown users of the database. The algorithm deals with three major parts, Environment Check, Roles and Permissions Check and finally the increment and decrement of permissions dynamically.

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“…In previous years, a lot of work has been done on RTDBS [8] [9], which are systems that are designed to manage applications where it is desirable to execute transactions timely using fresh and precise data [1]. Since the workload in this systems is unpredictable, the system may become quickly overloaded, leading to the decrease of the well-known RT-DBS performance criterion (the number of transactions that complete before their deadline).…”

Section: Introductionmentioning

confidence: 99%