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...

We present an efficient and practical lock-free implementation of a garbage collection scheme based on reference counting aimed for the use with arbitrary lock-free dynamic data structures. The scheme guarantees the safety of local as well as global references, supports arbitrary memory reuse, uses atomic primitives which are available in modern computer systems and provides an upper bound on t...

Abstract. This chapter explores the stock price impact of expirations of lock-up provisions that prevent insiders from selling their shares after the Initial Public Offering (IPO). I examine 172 lock-up expirations of 142 IPOs floated on Germany’s Neuer Markt. I detect significant negative abnormal returns and a twenty-five percent increase in trading volume surrounding lock-up expiration. The ...

Locks are often used in parallel applications to ensure correct behavior, but frequently induce performance bottlenecks caused by contention at frequently accessed locks. There are state-of-the-art locking algorithms, whose performance under high contention is superior to that of the most commonly used ones. However, some of these have a different interface, and adopting them incurs a reimpleme...

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...

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...

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...

The scalability of multithreaded applications on current multicore systems is hampered by the performance of lock algorithms, due to the costs of access contention and cache misses. In this paper, we propose a new lock algorithm, Remote Core Locking (RCL), that aims to improve the performance of critical sections in legacy applications on multicore architectures. The idea of RCL is to replace l...

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 ...

Der Vendor-Lock-in-Effekt bezeichnet die Abhängigkeit einer Investition von einem bestimmten Anbieter. Dieser kommt umso stärker zur Geltung, je länger die Nutzungsdauer der Investition (also z.B. die voraussichtliche Lebensdauer eines Softwaresystems) ist. Aus dem Vendor-Lock-in entstehen Risiken. Netzeffekte hingegen bezeichnen den Nutzen, den ein Anwender einer Technologie aus der Tatsache z...