the large number of applications manages time varying data. existing databasetechnology seldom supports temporal database, tdb, according to time aspects.these intrinsic temporal database applications rely on such database which storesand retrieves time referenced data. moreover, applications need to be managed oncommon data items access simultaneously and to be precluded from inconsistencyas s...

We present a modular approach to speciication and veriication of concurrency controllers by decou-pling their behavior and interface speciications. The behavior speciication of a concurrency controller deenes how its shared variables change their values whereas the interface speciication deenes the order in which a client thread should call its methods. We show that the concurrency controllers ...

Adaptable systems can improve reliability and performance by allowing dynamic reconfiguration. We are conducting a series of experiments on the RAID distributeel database system to siudy the cost and performance impHcations of providing static and dynamic adaptability, and for increasing the availabiliiy of daia iiems. Our studies of the cost of our adaptable implementation wefe conducted in th...

Combining concurrency and object orientation is still difficult. In an approach where methods are concurrency units, one of the main difficulties is the control of the behavior of objects. Our proposal is BDL a language allowing to express and to achieve this control. We propose a model where each object includes a so called "execution controller" programmed with BDL. This introduces a conceptu...

Many scheduling algorithms for databases have been developed in order to improve transaction responsiveness. Some developed algorithms meet special needs of real-time databases. These algorithms however, deal with temporal execution aspects , often disregarding semantics of data usage which could further improve performance. One such algorithm is Speculative Concurrency Control , which uses exe...

Applications using transactional memory may exhibit fluctuating (dynamic) available parallelism, i.e. the maximum number of transactions that can be committed concurrently may change over time. Executing large numbers of transactions concurrently in phases with low available parallelism will waste processor resources in aborted transactions, while executing few transactions concurrently in phas...

This paper focuses on issues related to implementing timed discrete-event systems (TDES) supervisors, and the concurrency and timing delay issues involved. In particular, we examine issues related to implementing TDES as sampled-data (SD) controllers. An SD controller is driven by a periodic clock and sees the system as a series of inputs and outputs. On each clock edge (tick event), it samples...

Transactional memory (TM) is a promising technique that simplifies parallel programming by supporting atomic and isolated execution of code sections. To provide robust performance and fairness guarantees, however, TM must dynamically adjust the degree of concurrency among transactions. To design an efficient concurrency controller for TM, critical system information, such as dependencies among ...

Concurrency control is one of the important problems in operation systems. Various studies have been reported to present different algorithms to address this problem, although a few attempts have been made to represent an overall view of the characteristics of these algorithms and comparison of their capabilities to each other. This paper presents a survey of the current methods for controlling...

In software-defined networks (SDN), the separation of the control and data-plane moves the concurrency control from the data-plane to a separate, now logically centralized controller program. As a result, despite its intention to simplify programming, the separation forces the programmer to deal with a spectrum of concurrent events (e.g. execution of controller programs, in-flight packets), a t...