Dependency theory e-learning tool

In this paper, we describe an e-learning tool that we have developed to assist University students studying Relational Schema design. The tool employs Expert System techniques to create a learning environment in which students can explore the concepts of dependency theory, and the normalization process. The tool is able to respond in an individualistic way to student input and allows students to construct their own learning environment and develop their understanding of the material at a pace that is controlled by the individual student. Our formative and summative tests indicate that the tool provides students with a different and valuable type of learning experience when compared with a traditional, textbook-based approach

Protecting federated databases using a practical implementation of a formal RBAC policy

This paper describes the use of formally specified RBAC policies for protecting federated relational database systems that are accessed over a wide area network. The method that is described combines a formally specified RBAC policy with both temporal and locational constraints. It does not depend on any security mechanism supported by a specific DBMS and is thus portable across platforms

An e-learning tool for database administration

In this paper, we describe an item of "intelligent" educational software that is intended to help students taking university computer science courses to understand the fundamentals of transaction scheduling. The software, implemented in PROLOG, empowers students to construct their own learning environment and is able to provide tailored forms of feedback to different types of learner. We describe the development and evaluation of the software, and we present details of the analysis of the results of our investigation into the effectiveness of the software as a teaching and learning tool. Our results suggest that our learning tool provides students with a different and valuable type of learning experience, which traditional methods do not provide

An e-learning tool for understanding schedule properties

In this paper, we describe an e-learning tool that we have developed to assist University students studying various modules on database systems. We use the acronym DTST (viz. a learning tool for Database Transaction Schedule Testing) to refer to our learning tool. DTST enables students to actively construct their own learning environment, it can respond in an individualistic way to student input, and it has a built-in web interface that makes it widely accessible. Field tests conducted on DTST suggest that it provides students with a different and valuable type of learning experience that traditional methods do not provide

An intelligent tutoring system for program semantics

In this paper, we describe an item of e-learning software that is intended to help students taking university computer science courses to understand the fundamentals of logic programming and deductive database semantics. The software is implemented in PROLOG and empowers students to explore their understanding of the semantics of logic programs and deductive databases. The software is also able to intelligently diagnose student misconceptions and includes a number of example programs/databases that permit students to test their understanding. We describe the development and evaluation of the software, and we present details of the analysis of the results of our investigation into the effectiveness of our e-learning tool. The results of our field study of the e-learning tool suggests that it of value in helpingstudents to understand program and database semantics

A database transaction scheduling tool in Prolog

In this paper, we describe an item of "intelligent" educational software that is intended to help students taking university computer science courses to understand the fundamentals of transaction scheduling. The software, implemented in PROLOG, empowers students to construct their own learning environment and is able to provide tailored forms of feedback to different types of learner. We describe the development and evaluation of the software, and we present details of the analysis of the results of our investigation into the effectiveness of the software as a teaching and learning tool. Our results suggest that our learning tool provides students with a different and valuable type of learning experience, which traditional methods do not provide

A logic programming e-learning tool for teaching database dependency theory

In this paper, we describe an "intelligent" tool for helping to teach the principles of database design. The software that we present uses PROLOG to implement a teaching tool with which students can explore the concepts of dependency theory, and the normalization process. Students are able to construct their own learning environment and can develop their understanding of the material at a pace that is controlled by the individual student

Split-sideband spectroscopy in slowly modulated optomechanics

Optomechanical coupling between the motion of a mechanical oscillator and a cavity represents a new arena for experimental investigation of quantum effects on the mesoscopic and macroscopic scale.The motional sidebands of the output of a cavity offer ultra-sensitive probes of the dynamics. We introduce a scheme whereby these sidebands split asymmetrically and show how they may be used as experimental diagnostics and signatures of quantum noise limited dynamics. We show split-sidebands with controllable asymmetry occur by simultaneously modulating the light-mechanical coupling $g$ and $\omega_M$ - slowly and out of-phase. Such modulations are generic but already occur in optically trapped set-ups where the equilibrium point of the oscillator is varied cyclically. We analyse recently observed, but overlooked, experimental split-sideband asymmetries; although not yet in the quantum regime, the data suggests that split sideband structures are easily accessible to future experiments

Maternal Expression Relaxes Constraint on Innovation of the Anterior Determinant, bicoid

The origin of evolutionary novelty is believed to involve both positive selection and relaxed developmental constraint. In flies, the redesign of anterior patterning during embryogenesis is a major developmental innovation and the rapidly evolving Hox gene, bicoid (bcd), plays a critical role. We report evidence for relaxation of selective constraint acting on bicoid as a result of its maternal pattern of gene expression. Evolutionary theory predicts 2-fold greater sequence diversity for maternal effect genes than for zygotically expressed genes, because natural selection is only half as effective acting on autosomal genes expressed in one sex as it is on genes expressed in both sexes. We sample an individual from ten populations of Drosophila melanogaster and nine populations of D. simulans for polymorphism in the tandem gene duplicates bcd, which is maternally expressed, and zerknüllt (zen), which is zygotically expressed. In both species, we find the ratio of bcd to zen nucleotide diversity to be two or more in the coding regions but one in the noncoding regions, providing the first quantitative support for the theoretical prediction of relaxed selective constraint on maternal-effect genes resulting from sex-limited expression. Our results suggest that the accelerated rate of evolution observed for bcd is owing, at least partly, to variation generated by relaxed selective constraint