This paper explores the feasibility of re-expressing concurrent algorithms with explicit locks in terms of lock free code written using Haskell’s implementation of software transactional memory. Experimental results are presented which show that for multi-processor systems the simpler lock free implementations offer superior performance when compared to their corresponding lock based implementa...

A network of processes is lock free if every message produced in it is eventually consumed and if every process waiting for a message eventually receives one. We study a type system guaranteeing that well-typed process networks are lock free. Despite its minimality, our type system subsumes existing type-based approaches for lock freedom. In particular, we show that interactions whose lock free...

Lock acquisition of a suspended optical cavity can be a highly stochastic process and is therefore nontrivial. Guided lock is a method to make lock acquisition less stochastic by decelerating the motion of the cavity length based on an extrapolation of the motion from an instantaneous velocity measurement. We propose an improved scheme that is less susceptible to seismic disturbances by incorpo...

The occurrence of lock-in, defined as the local synchronization between the vortex shedding frequency and the cross-flow structural vibration frequency, is investigated in the case of a tensioned beam of length to diameter ratio 200, free to move in both the in-line and cross-flow directions, and immersed in a linear shear current. Direct numerical simulation is employed at three Reynolds numbe...

taDOM* protocols are designed to provide lock-based approach to handle multiple access to XML databases. The notion of taDOM+ protocol is formalized and generalized and a formal model of taDOM+ lock manager that is parameterized in the number of transactions and in the size of database is represented. An important class of safety properties of taDOM+ lock managers were proven to be checked by e...

A lock-in amplifier is a versatile instrument frequently used in physics research. However, many students struggle with the basic operating principles of a lock-in amplifier which can lead to a variety of difficulties. To improve students’ understanding, we have been developing and evaluating a research-based tutorial which makes use of a computer simulation of a lock-in amplifier. The tutorial...

AIM The aim of this study was (i) to evaluate the formation of air bubbles in the apical region of root canal (apical vapor lock) during syringe irrigation, using cone beam computed tomography (CBCT) and (ii) comparative evaluation of the elimination of an established vapor lock by EndoActivator, ultrasonics, and manual dynamic agitation (MDA), using CBCT. MATERIALS AND METHODS A total of 60 ...

The Java Programming Language permits synchronization operations (lock, unlock, wait, notify) on any object. Synchronization is very common in applications and is endemic in the library code upon which applications depend. It is therefore critical that a monitor implementation be both space-efficient and time-efficient. We present a locking protocol, the Relaxed-Lock, that satisfies those requ...

This paper introduces optimistic lock synchronization using the group write consistency model (GWC). GWC guarantees strict ordering of all shared writes in a processor group. In optimistic synchronization, if a lock-requesting processor can assume that the lock is free, execution of mutually exclusive code starts immediately. Wrong assumption results in rollback. Shared variable updates remain ...

The problem of model checking threads interacting purely via the standard synchronization primitives is key for many concurrent program analyses, particularly dataflow analysis. Unfortunately, it is undecidable even for the most commonly used synchronization primitive, i.e., mutex locks. Lock usage in concurrent programs can be characterized in terms of lock chains, where a sequence of mutex lo...