No abstract

Modern smartphones feature multiple applications which access shared data on the solid state storage within the device. As applications become more complex, contention over this memory resource is becoming an issue. This leads to increased battery drain as the applications are forced to touch the solid state device repeatedly after failing to retrieve or store data due to contention from other applications. We describe an optimistic concurrency control algorithm, combining a novel Read-WriteValidate phase sequence with virtual execution. The protocol is suitable for governing transactions operating on databases residing on resource-constrained devices. Increasing energy efficiency and reducing latency are primary goals for our algorithm. We show that this is achieved by reducing persistent store access, and satisfy realtime requirements via transaction scheduling that affords greater determinism. AbstractModern smartphones feature multiple applications which access shared data on the solid state storage within the device. As applications become more complex, contention over this memory resource is becoming an issue. This leads to increased battery drain as the applications are forced to touch the solid state device repeatedly after failing to retrieve or store data due to contention from other applications. We describe an optimistic concurrency control algorithm, combining a novel Read-Write-Validate phase sequence with virtual execution. The protocol is suitable for governing transactions operating on databases residing on resource-constrained devices. Increasing energy efficiency and reducing latency are primary goals for our algorithm. We show that this is achieved by reducing persistent store access, and satisfy real-time requirements via transaction scheduling that affords greater determinism. About the authorsKamal Solaiman is a Phd student in the School of Computing Science at Newcastle University. Abstract -Modern smartphones feature multiple applications which access shared data on the solid state storage within the device. As applications become more complex, contention over this memory resource is becoming an issue. This leads to increased battery drain as the applications are forced to touch the solid state device repeatedly after failing to retrieve or store data due to contention from other applications. We describe an optimistic concurrency control algorithm, combining a novel Read-Write-Validate phase sequence with virtual execution. The protocol is suitable for governing transactions operating on databases residing on resource-constrained devices. Increasing energy efficiency and reducing latency are primary goals for our algorithm. We show that this is achieved by reducing persistent store access, and satisfy real-time requirements via transaction scheduling that affords greater determinism. Matthew Brook is a Phd student in the

High frequency trading (HFT) environments provide technologies that enable algorithmic trading within automated marketplaces. The most prominent example of an HFT environment is within equity trading, where many millions of trades are achieved at a high volume to gain a reasonable cumulative profit. Such environments rely on low latency/high performance technologies to allow trades to react in a timely manner to market volatility. However, sometimes the volatility of the market goes beyond what supporting infrastructure can allow, resulting in erroneous behaviour of the marketplace. In this paper we tackle the problem of managing market volatility to limit erroneous market behaviour. Our approach is unique in that it is non-dependent on the trading environment itself and self-regulates based only on trading frequency and contention. We demonstrate our results and show that by managing trade injection rates and contention of shared state the volatility of HFT environments can be managed appropriately and in an automated manner.

This paper presents a protocol which utilizes semantically aware, transaction-based contention management to reduce rollback and improve consistency in massively multiuser systems. Of particular relevance to massively multiplayer online games (MMOGs), the proposed system is adaptive and scales with respect to connection latency. This paper presents some background to the area of state management and consistency in MMOGs, and their impact on user quality of service. Our solution is then outlined in significant detail, with particular attention paid to the manner in which it maps to the structure of MMOGs. A simulation is demonstrated and its behaviors discussed in-depth in order to support arguments regarding the suitability of the protocol.INDEX TERMS Consistency, distributed systems, MMOGs.

The ubiquity of smart portable devices has led to concurrency control for the mobile network becoming an area of growing concern. Conventional optimistic concurrency control techniques require retries of failed or disputed transactions, which place additional drain on the energy consumption of both the network and the smart device. We present a Distributed Later Validation Earlier Write Optimistic Concurrency Control (DLVEW) algorithm to efficiently handle transactions running on the server side without disturbing transactions running on clients. Our simulation shows an increase in throughput and reduction in both the response time and the number of missed deadlines of transactions. The corresponding reduction in contentious transactions needing to be restarted leads to a lower power cost for the network as a whole.