In [7], Jan Černý conjectured that an arbitrary directable automaton with n states has a directing word of length not longer than (n−1). This conjecture is one of the most longstanding open problems in the theory of finite automata. Most of papers dealing with this conjecture reduce the problem to special classes of automata. In present paper we deal with this conjecture in the class of automat...

Using efficient point-to-point communication channels is critical for implementing fine grained parallel program on modern shared cache multicore architectures. This report discusses in detail several implementations of wait-free Single-Producer/Single-Consumer queue (SPSC), and presents a novel and efficient algorithm for the implementation of an unbounded wait-free SPSC queue (uSPSC). The cor...

Stochastic gradient descent (SGD) and its variants have attracted much attention in machine learning due to their efficiency and effectiveness for optimization. To handle largescale problems, researchers have recently proposed several lock-free strategy based parallel SGD (LF-PSGD) methods for multi-core systems. However, existing works have only proved the convergence of these LF-PSGD methods ...

To make the most effective use of parallel machines that are being built out of increasingly large multicore chips, researchers are exploring the use of programming models comprising a mixture of MPI and threads. Such hybrid models require efficient support from an MPI implementation for MPI messages sent from multiple threads simultaneously. In this paper, we explore the issues involved in des...

Network intrusion prevention systems provide proactive defense against security threats by detecting and blocking attack-related traffic. This task can be highly complex, and therefore, software-based network intrusion prevention systems have difficulty in handling high speed links. This paper describes the design and implementation of a high-performance network intrusion prevention system that...

Stencil-based kernels constitute the core of many important scientific applications on blockstructured grids. Unfortunately, these codes achieve a low fraction of peak performance, due primarily to the disparity between processor and main memory speeds. In this paper, we explore the impact of trends in memory subsystems on a variety of stencil optimization techniques and develop performance mod...

In a multithreaded execution, each thread can be thought of as running on its own virtual processor, with several virtual processors multiplexed onto a single physical processor. At any given time, some of these virtual processors are either sending or waiting for messages. When the degree of multithreading is high, there is a high potential load on the interconnection network. It is important ...