The advent of high-speed networks will enable the deployment of data-server systems currently used in localarea networks, over wide-area networks. The users of these systems will have the same high expectations with respect to performance parameters such as the transaction throughput, response time and system reliability as in the case of local-area networks. Thus, it is important to study the ...

In this paper, we discuss the initial results of a detailed simulation of the group two-phase locking (g-2PL) protocol which was developed for gigabit-networked databases. These results show that the grouping of lock grants, client-end caching and data migration proposed in the g-2PL protocol improves the transaction response time upto 25% at moderate to high network latencies, when compared to...

This paper builds on altruistic locking which is an extension of 2PL. It allows more relaxed rules as compared to 2PL. But altruistic locking too enforces some rules which disallow some valid schedules (present in VSR and CSR) to be passed by AL. This paper proposes a multiversion variant of AL which solves this problem. The report also discusses the relationship or comparison between different...

The use of two-phase locking (2PL) to enforce serialization in today’s Software Transactional Memory (STM) systems leads to poor performance for programs with long-running transactions and considerable data sharing. We propose the use of ConflictSerializability (CS) instead of 2PL. The use of CS allows transactions to complete when they would have either stalled or aborted with 2PL, potentially...

A read-only transaction (ROT) does not modify any data. The main issues regarding processing ROTs are correctness, data currency and performance. Two-phase Locking (2PL) protocol is widely used for concurrency control with serializabilty as correctness criteria. Even though 2PL processes ROTs correctly with no data currency related issues, the performance deteriorates as data contention increas...

The detection of differential item functioning is crucial for the psychometric evaluation multistage tests. This paper discusses five approaches presented in literature: logistic regression, SIBTEST, analytical score-based tests, bootstrap and permutation First, using an simulation study inspired by a real-life large-scale educational assessment, we compare with respect to their type I error ra...

This paper addresses two basic issues. First, the feasibility of the model is exhibited by introducing a relatively straightforward and efficient parallel commti phase algorithm in which no I/O operations are associated with a critical section of the TM. Second, by simulation experiments, a concurrency control method in which readers use certification whereas writers use 2PL and do not wait for...

Researchers commonly apply item response theory (IRT) models to binary and ordinal items in order to measure an underlying trait using a collection of observed responses to test questions or items. For binary items, a common IRT model is the two parameter logistic (2PL) form. Assume that we have observed p item responses for n individuals where a correct responses is designated with a ’1’ and a...

 With the rapid advances in mobile computing technology, there is an increasing demand for processing realtime transactions in a mobile environment. This paper studies concurrency control problem in mobile distributed real-time database systems (MDRTDBS). Based on the High Priority Two Phase Locking (HP-2PL) scheme, we propose a distributed real-time locking protocol, called Distributed High P...

The performance of high-volume transaction processing systems for business applications is determined by the degree of contention for hardware resources as well as for data. Hardware resource requirements may be met cost-effectively with a data-partitioned or shared-nothing architecture. However, the two-phase locking (2PL) concurrency control method may restrict the performance of a shared-not...