There is an ever-increasing demand for more complex transactions and higher throughputs in transaction processing systems leading to higher degrees of transaction concurrency and, hence, higher data contention. The conventional two-phase locking (2PL) Concurrency Control (CC) method may, therefore, restrict system throughput to levels inconsistent with the available processing capacity. This is...

A read-only transaction (ROT) does not modify any data. Efforts are being made in the literature to improve the performance of ROTs without correctness and data currency issues. The widely used twophase locking protocol (2PL) processes the transactions without any correctness and data currency issues. However, the performance of 2PL deteriorates with data contention. Snapshot isolation (SI)-bas...

Research in the concurrency control of real-time data access over mobile networks is receiving growing attention. With possibly lengthy transmission delay and frequent disconnection, traditional concurrency control mechanisms may become very costly and time-consuming in mobile distributed real-time database systems (MDRTDBS). Due to limited bandwidth and unpredictable behavior of mobile network...

This study aims to examine the effects of mixture item response theory (IRT) models on parameter estimation and classification accuracy under different conditions. The manipulated variables simulation are set as IRT (Rasch, 2PL, 3PL); sample size (600, 1000); number items (10, 30); latent classes (2, 3); missing data type (complete, at random (MAR) not (MNAR)), percentage (10%, 20%). Data were ...

Previous studies (e.g., [5]) have shown that optimistic concurrency control (OCC) generally performs better than lock-based protocols in disk-based real-time database systems (RTDBS). In this paper we compare the two concurrency control protocols in both disk-based and memory-resident multiprocessor RTDBS. Based on their performance characteristics, a new lock-based protocol, called Two Phase L...

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...

This research aims to describe the quality of critical thinking skill test fluid mechanics material in senior high schools Makassar City. The emphasis is content validity aspect, characteristics each item for One-Parameter Logistic (1PL) model, Two-Parameter (2PL) dan Three-Parameter (3PL) model. It a descriptive quantitative with subject all student responses skills at There were 726 responses...

In the paper we present a formal model of real-time database (RTDB) systems using Duration Calculus (DC). First, we give a formal speciication of the correctness criterion for the executions of transaction systems and of the Two Phase Locking Concurrency Control Protocol (2PL-CCP). We also give a formal proof for the correctness of the 2PL-CCP using the DC proof system. Then, we present a forma...

In the paper we present a formal model of real-time database (RTDB) systems using Duration Calculus (DC). First, we give a formal specification of the correctness for the executions of transaction systems and the Two Phase Locking Concurrency Control Protocol (2PL-CCP). We also give a formal proof for the correctness of the 2PL-CCP using the DC proof system. Then, we present a formal descriptio...

In this article we study the bivariate truncated moment problem (TMP) of degree 2k on union parallel lines. First present an alternative proof Fialkow's solution [28] to TMP two lines (TMP–2pl) using Hamburger (THMP). We add a new equivalent solvability condition, which is then used together with THMP, solve three (TMP–3pl), our second main result article. Finally, establish sufficient conditio...