File replacement algorithm for storage resource managers in data grids

The main problem in data grids is how to provide good and timely access to huge data given the limited number and size of storage devices and high latency of the interconnection network. One approach to address this problem is to cache the files locally such that remote access overheads are avoided. Caching requires a cache-replacement algorithm, which is the focus of this paper. Specifically, we propose a new replacement policy and compare it with an existing policy using simulations. The results of the simulation show that the proposed policy performs better than the baseline policy.

Design, format, validity and reliability of mutiple choice questions for use in nursing research and education

Multiple choice questions are used extensively in nursing research and education and play a fundamental role in the design of research studies or educational programs. Despite their widespread use, there is a lack of evidence-based guidelines relating to design and use of multiple choice questions. Little is written about their format, structure, validity and reliability of in the context of nursing research and/or education and most of the current literature in this area is based on opinion or consensus. Systematic multiple choice question design and use of valid and reliable multiple choice questions are vital if the results of research or educational testing are to be considered valid. Content and face validity schould be established by expert panel review and construct validity should be established using ‘key check’, item discrimination and item difficulty analyses. Reliability measures include internal consistency and equivalence. Internal consistency should be established by determination of internal consistency using reliability coefficients while equivalence should be established using alternate form correlation. This paper reviews literature related to the use of multiple choice questions, current design recommendations and processes to establish reliability and validity, and discusses implications for their use in nursing research and education.

Investigation of an optimistic based concurrency control mechanism for parallel file systems

Parallel file systems offer improved performance over traditional file systems by allowing processes to access file data, stored over a number of disks, in parallel. When this file is to be accessed by many processes at the same time for reading and writing, the problem of maintaining file consistency is introduced. The general approach to maintaining file consistency is through the use locks which grant a single process exclusive access to the file. Existing studies have found parallel file systems and associated applications rarely experience conflict, resulting in unnecessary overheads from locks being acquired. This paper examines an alternate approach to maintaining file consistency, which is based on optimistic concurrency control. This approach was shown to have a much smaller overhead when compared with traditional lock-based approaches; especially in situations when there is little contention. This paper presents the design, implementation and initial testing results of an optimistic based concurrency control mechanism.

An effective and efficient testing methodology for correctness testing for file recovery tools

We hereby develop an effective and efficient testing methodology for correctness testing for file recovery tools across different file systems. We assume that the tool tester is familiar with the formats of common file types and has the ability to use the tools correctly. Our methodology first derives a testing plan to minimize the number of runs required to identify the differences in tools with respect to correctness. We also present a case study on correctness testing for file carving tools, which allows us to confirm that the number of necessary testing runs is bounded and our results are statistically sound.

A scheme for content based retrieval of music data in MIDI format

With phenomenal increases in the generation and storage of digital audio data in several applications, there is growing need for organizing audio data in databases and providing users with fast access to desired data. This paper presents a scheme for the content-based query and retrieval of audio data stored in MIDI format. This is based on extraction of melody from the MIDI files and suitably comparing with the melody of the query. The results of retrieval using the proposed algorithm are presented.

Mathematical power of special-needs pupils : an ICT-based dynamic assessment format to reveal weak pupils' learning potential

This paper reports a study aimed at revealing special-educational-needs pupils' learning potential by means of an ICT-based assessment including a dynamic visual tool that might help pupils when solving mathematics problems. The study focused on subtraction problems up to 100, which require 'borrowing'. These problems, in which the value of the ones-digit of the subtrahend is larger than the ones-digit of the minuend, are known as a serious difficulty for weak pupils in mathematics. Seven of such problems from a standardised test were placed in the ICT environment. Data were collected from two test conditions: the standardised written test format and the ICT version of the test items including the tool that provided pupils with a set of virtual manipulatives. The 37 pupils involved in the study were 8–12 years old and from two special-education schools in the Netherlands. Comparison of the performance scores in the two formats showed that an ICT-based assessment format, including a dynamic visual tool, can reveal weak pupils' learning potential and strategy use. The study also pointed out that 'partial-tool use', ie, not carrying out the complete subtraction operation with the tool, can provide sufficient support to find the correct answer.

Modeling data processing activity to assess the internal control function

This thesis describes research that was conducted into the potential of modeling the activities of the Data Processing Department as an aid to the computer auditor. A methodology is composed to aid in the evaluation of the Internal Controls, particularly the General Controls relative to computer processing. Consisting of three major components, the methodology enables the auditor to model the presumed activities of the Data Processing Department against the actual activities, as recorded on the Operating System Log. The first component of the methodology is the construction and loading of a model of the presumed activities of the Data Processing Department from its verbal, scheduled, and reported activities. The second component is the generation of a description of the actual activities of the Data Processing Department from the information recorded on the Operating System Log. This is effected by reducing the Operating System Log to the format described by the Standard Audit File concept. Finally, the third component in the methodology is the modeling process itself. This is in fact a new analysis technique proposed for use by the EDP auditor. The modeling process is composed of software that compares the model developed and loaded in the first component, with the description of actual activity as collated by the second component. Results from this comparison are then reviewed by the auditor, who determines if they adequately depict the situation, or whether the models description as specified in the first component requires to be altered, and the modeling process re-initiated. In conducting the research, information and data from a production installation was used. Use of the ‘real-world’ input proved both the feasibility of developing a model of the reported activities of the Data Processing Department, and the adequacy of the operating system log as a source of information to report the departments actual activities. Additionally, it enabled the involvement and comment of practicing auditors. The research involved analysis of the effect of EDP on the audit process, structure of the EDP audit process, data reduction, data structures, model formalization, and model processing software. Additionally, the Standard Audit File concept was verified through its use by practising auditors, and expanded by the development of an indexed data structure, which enabled its analysis to be conducted interactively. Results from the trial implementation of the research software and methodology at a production installation confirmed the research hypothesis that the activities of the Data Processing Department could be modelled, and that there are substantial benefits from the EDP auditor in analysing this process. The research in fact provides a new source of information, and develops a new analysis technique for the EDP auditor. It demonstrates the utilization of computer technology to monitor itself for the audit function, and reasserts auditor independence by providing access to technical detail describing the processing activities of the computer.

Sharable file searching in unstructured peer-to-peer systems

The existing sharable file searching methods have at least one of the following disadvantages: (1) they are applicable only to certain topology patterns, (2) suffer single point failure, or (3) incur prohibitive maintenance cost. These drawbacks prevent their effective application in unstructured Peer-to-peer (P2P) systems (where the system topologies are changed time to time due to peers' frequently entering and leaving the systems), despite the considerable success of sharing file search in conventional peer-to-peer systems. Motivated by this, we develop several fully dynamic algorithms for searching sharing files in unstructured peer to peer systems. Our solutions can handle any topology pattern with small search time and computational overhead. We also present an in-depth analysis that provides valuable insight into the characteristics of alternative effective search strategies and leads to precision guarantees. Extensive experiments validate our theoretical findings and demonstrate the efficiency of our techniques in practice.

OST : A transaction based online social trust model for social network and file sharing security

The continuous growth of the users pool of Social Networking web sites such as Facebook and MySpace, and their incessant augmentation of services and capabilities will in the future, meet and compare in contrast with today's Content distribution Networks (CDN) and Peer-to-Peer File sharing applications such as Kazaa and BitTorrent, but how can these two main streams applications, that already encounter their own security problems cope with the combined issues, trust for Social Networks, content and index poisoning in CDN? We will address the problems of Social Trust and File Sharing with an overlay level of trust model based on social activity and transactions, this can be an answer to enable users to increase the reliability of their online social life and also enhance the content distribution and create a better file sharing example. The aim of this research is to lower the risk of malicious activity on a given Social Network by applying a correlated trust model, to guarantee the validity of someone's identity, privacy and trustfulness in sharing content.

Comparison of the traditional problem-based learning format and larger, directed, independent study groups

 Problem based learning has been implemented as a pedagogical tool world-wide across a range of health professions since its inception at McMaster University, Canada, in 1969 (Neville & Norman, 2007). In addition to enhancing knowledge and understanding it is also claimed that PBL develops communication skills, encourages teamwork, sharing of information and respect for others, furthers problem solving skills, and allows students to assume responsibility for their own learning (Wood, 2003). However, the cognitive outcomes of PBL and traditional pedagogy (based on didactic teaching) are similar and hence widespread adoption of PBL has been questioned (see Colliver, 2000). Criticisms of PBL include its resource hungry nature, requiring, as it does, experienced tutors to facilitate .learning across several clusters of students dealing with the same problem. Given the actual and anticipated increase in numbers of medical students in Australia other strategies that retain the advantages of PBL, while minimising the demands on faculty, should now be explored. This paper reports our experience with a modification of the traditional PBL approach, termed PBLplus. This innovation was trialled in a regional clinical school, attached to a hospital, with a group of 19 graduate entry students, who had completed an integrated Year 1 / 2 of the MBBS. PBLplus involved allocating students from the whole class to three task directed groups. Groups had specified assignments to complete to facilitate learning across the whole class. A tutor listened to student presentations and provided an interactive presentation. Hence use of tutors was made more efficient, and faculty input was more specialised.

Zeroes of Riemann's zeta function on the critical line with 20000 decimal digits accuracy

The first 12000 zeroes of Riemann's zeta function on the critical line with 20000 decimal digits accuracy. Format: the zeroes are in text file listed consecutively in decimal representation, each zero starts on a new line.

Zeroes of zeta function presented in this file were calculated on MASSIVE cluster (www.massive.org.au) using Python and packages MPmath version 0.17 and gmpy version 2.1, with a Newton based algorithm proposed by Fredrik Johansson with precision set to 20000 decimal digits. Partial recalculation with higher precision didn't show any loss of accuracy so we expect that the values are correct up to, possibly, a few last digits. We express our thanks to Fredrik Johansson for this algorithm and for development of MPmath as well.

An empirical case for introductory psychology tutorials in a large-class format

This study examined the effectiveness of an instructional format that Involved conducting introductory psychology tutorials in large conventional lecture theatres with over 100 students per class. We maximised the use of skilled tutors, sharing of student perspectives, and cooperative learning in delivering interactive, active learning activities, Students (N = 284) within each class were randomly assigned to smaller groups that were scaled within the same large class environment. Students reported positive perceptions of their learning experience at an end-of-semester survey. Moreover, they performed significantly better in a major assessment on the tutorial component than a previous cohort taught in conventional small tutorial classes. Our finding indicate that active learning techniques can be implemented just as effectively in a large class tutorial format. These findings have practical implications for designing cost effective yet pedagogically vigorous instructional formats for introductory psychology and other liberal arts courses.

The missing puzzle : birth of a format

 As new hybrid TV formats are developed story reamins the only consitent genre. This thesis is an empirical investigation that expores the genesis of Missing Persons Unit and television series that used hybrid styles of production to reach and stay in the number one position on Australian television.