Mutual-exclusion locks are currently the most popular mechanism for interpro-cess synchronisation, largely due to their apparent simplicity and ease of implementation. In the parallel-computing environments that are increasingly commonplace in high-performance applications, this simplicity is deceptive: mutual exclusion does not scale well with large numbers of locks and many concurrent threads...

An object is lock-free if it guarantees that in a system where multiple threads are manipulating the object, some thread will complete its operation on the object in a finite number of steps, no matter what happens to other threads. More practically, lock-free programming is a technique to achieve thread safety without the use of locks, which are the current standard. Lock-free objects (LFOs) h...

Techniques for Constructing Efficient Lock-free Data Structures Trevor Brown Doctor of Philosophy Graduate Department of Computer Science University of Toronto 2017 Building a library of concurrent data structures is an essential way to simplify the difficult task of developing concurrent software. Lock-free data structures, in which processes can help one another to complete operations, offer ...

A novel visible multi-digit DNA keypad lock system was fabricated based on split G-quadruplex DNAzyme and silver microspheres. The final result of the keypad lock can be easily recognized by the naked eye and the number of inputs for the keypad lock can be flexibly adjusted. This molecular platform showed excellent scalability and flexibility.

The rotor-router model, also called the Propp machine, was first considered as a deterministic alternative to the random walk. It is known that the route in an undirected graph G = (V,E), where |V | = n and |E| = m, adopted by an agent controlled by the rotor-router mechanism forms eventually an Euler tour based on arcs obtained via replacing each edge in G by two arcs with opposite direction. ...

To maintain the stability trajectory of vehicles under critical driving conditions, anti lock-anti skid controllers, consisting of four anti-lock sub-controllers for each wheel and two anti-skid sub-controllers for left and right pair wheels have been separately designed. Wheel and body systems have been simulated with seven degrees of freedom to evaluate the proper functioning of controllers. ...

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 Permit based Locking design pattern provides fast acquisition and release of locks without network communication even in distributed systems build around a central lock server. Instead of plain locks, the server manages "permits to lock", and passes them to those clients which probably need the lock next. If a client hosts a permit, the associated lock can be acquired immediately without se...