The exibility of nested transactions is generally provided at the expense of a more complex locking mechanism which must deal with expensive lock inheritance. In this paper, we give a solution for eecient lock inheritance. Our solution does not change the original nested transactions model but does revisit its locking rules using set-oriented semantics. This allows us to trade the cost of lock ...

There are many mechanisms for concurrency control in high-level programming languages. In Java, the original mechanism for concurrency control, based on synchronized blocks, is lexically scoped. For more flexible control, Java 5 introduced non-lexical operators, supporting lock primitives on re-entrant locks. These operators may lead to run-time errors and unwanted behavior; e.g., taking a lock...

The idea of data transfer by physically severed connections has been applied in a simple realization of the Lock-Keeper technology, the SingleGate Lock Keeper system. By means of it, the possibility of direct attacks to a protected network can be eliminated entirely and data can be exchanged between two networks through a completely secure and reliable way. As an advanced implementation of this...

Based on loosely coupled services in an XML engine, we describe how to realize fine-grained lock protocols, which can guarantee transaction isolation for applications using different language models. We illustrate the superiority of the taDOM lock protocol family and its tailormade lock modes and lock granules adjusted to the XML language model. We emphasize the importance of a prefix-based nod...

Synchronization overhead may limit the number of applications that can take advantage of a shared-memory abstraction on top of emerging network of workstation organizations. While the programmer could spend additional efforts into getting rid of such overhead by restructuring the computation, this paper focuses on a simpler approach where the overhead of lock operations is hidden through lock p...

The choice of lock objects in concurrent programs can affect both performance and correctness, a burden of complexity for programmers. Recently, various automated lock allocation and assignment techniques have been proposed, each aiming primarily to minimize the number of conflicts between critical sections. However, practical performance depends on a number of important factors, including the ...

Stanford Research Systems phone: (408)744-9040 www.thinkSRS.com Lock-in amplifiers are used to detect and measure very small AC signalsall the way down to a few nanovolts. Accurate measurements may be made even when the small signal is obscured by noise sources many thousands of times larger. Lock-in amplifiers use a technique known as phase-sensitive detection to single out the component of t...

We surveyed infectious diseases physicians to determine their practice patterns with regard to both antimicrobial lock prophylaxis and antimicrobial lock therapy. Antimicrobial lock prophylaxis is relatively uncommon; only 19% of infectious diseases physicians reported using it at least once. Although antimicrobial lock therapy is more commonly used, we found a significant variation in practice...

An atomic block is a language construct that simplifies the programming of critical sections. In the past, software transactional memory (STM) and lock inference have been used to implement atomic blocks. Both approaches have strengths and weaknesses. STM provides fine-grained locking but has high overheads due to logging and potential rollbacks. Lock inference is a static analysis that compute...

In this paper we break a knapsack based two-lock cryptosystem proposed at ICICS’03 [7]. The two-lock cryptosystem is a commutative encryption algorithm that is very useful for the construction of the general t-out-of-n oblivious transfers and millionaire protocol. However, our analysis shows that the proposed knapsack based two-lock cryptosystem is extremely insecure. The serious flaw is that t...