Distributed software transactional memory (STM) promises to alleviate difficulties with lockbased (distributed) synchronization and object performance bottlenecks in distributed systems. The existing distributed STM model based on globally-consistent contention management policies may abort many transactions that could potentially commit without violating correctness. To reduce unnecessary abor...

Some of the simulation work performed by the computational aerosciences project under the NASA Constellation program is presented. The challenges of simulating the powered flight of the Orion launch abort vehicle for the purposes of building an aerodynamics database are discussed. During an abort this vehicle fires both a four-nozzle abort motor together with an eight-nozzle attitude control mo...

Supersonic flow over a capsule-shaped abort system with angle of attack (AoA) of α, which is boosted by supersonic aerodynamic interference, is investigated numerically through the 3D simulation. The objective of this study is to examine the effects of AoA on aerodynamic stability. In the previous study, the flowfield around this system at α = 0 is unsteady and has a strong periodic flow oscill...

The LHC beam dump extraction kicker system consists per ring of 15 magnets and their pulse generators. Their task is to extract the beams on request, over the whole operational beam energy range and synchronously with the beam abort gap. This operation must be fail-safe to avoid damage to accelerator equipment by undesired beam losses. The control system of the LHC beam dump kickers will be bas...

The paper considers the addition of access control to a number of transactional memory implementations, and studies its impact on the information flow security of such systems. Even after the imposition of access control, the Unbounded Transactional Memory due to Ananian et al, and most instances of a general scheme for transactional conflict detection and arbitration due to Scott, are shown to...

Backtracking search algorithms are useful in many domains, from SAT solvers to artificial intelligences for playing games such as chess. Searching disjoint branches can, inherently be done in parallel though it can considerably increase the amount of work that the algorithm does. Such parallelism is speculative, once a solution is found additional work is irrelevant, but the individual branches...

Priority Ceiling Protocol (PCP) is a well-known resource access protocol for hard real-time systems. However, it has a problem of ceiling blocking which imposes a great hindrance to task scheduling in mixed real-time systems where tasks may have different criticality. In this paper, a new resource access protocol called the Conditional Abortable Priority Ceiling Protocol (CA-PCP) is proposed. I...

We consider the situation where a large number n of players want to securely compute a large function f with security against an adaptive, malicious adversary which might corrupt t < cn of the parties for some given c ∈ [0, 1). In other words, only some arbitrarily small constant fraction of the parties are assumed to be honest. For any fixed c, we consider the asymptotic complexity as n and th...