A statistical model of internet traffic.

PhDWe present a method to extract a time series (Number of Active Requests (NAR)) from web cache logs which serves as a transport level measurement of internet traffic. This series also reflects the performance or Quality of Service of a web cache. Using time series modelling, we interpret the properties of this kind of internet traffic and its effect on the performance perceived by the cache user. Our preliminary analysis of NAR concludes that this dataset is suggestive of a long-memory self-similar process but is not heavy-tailed. Having carried out more in-depth analysis, we propose a three stage modelling process of the time series: (i) a power transformation to normalise the data, (ii) a polynomial fit to approximate the general trend and (iii) a modelling of the residuals from the polynomial fit. We analyse the polynomial and show that the residual dataset may be modelled as a FARIMA(p, d, q) process. Finally, we use Canonical Variate Analysis to determine the most significant defining properties of our measurements and draw conclusions to categorise the differences in traffic properties between the various caches studied. We show that the strongest illustration of differences between the caches is shown by the short memory parameters of the FARIMA fit. We compare the differences revealed between our studied caches and draw conclusions on them. Several programs have been written in Perl and S programming languages for this analysis including totalqd.pl for NAR calculation, fullanalysis for general statistical analysis of the data and armamodel for FARIMA modelling

Using program behaviour to exploit heterogeneous multi-core processors

Multi-core CPU architectures have become prevalent in recent years. A number of multi-core CPUs consist of not only multiple processing cores, but multiple different types of processing cores, each with different capabilities and specialisations. These heterogeneous multi-core architectures (HMAs) can deliver exceptional performance; however, they are notoriously difficult to program effectively. This dissertation investigates the feasibility of ameliorating many of the difficulties encountered in application development on HMA processors, by employing a behaviour aware runtime system. This runtime system provides applications with the illusion of executing on a homogeneous architecture, by presenting a homogeneous virtual machine interface. The runtime system uses knowledge of a program's execution behaviour, gained through explicit code annotations, static analysis or runtime monitoring, to inform its resource allocation and scheduling decisions, such that the application makes best use of the HMA's heterogeneous processing cores. The goal of this runtime system is to enable non-specialist application developers to write applications that can exploit an HMA, without the developer requiring in-depth knowledge of the HMA's design. This dissertation describes the development of a Java runtime system, called Hera-JVM, aimed at investigating this premise. Hera-JVM supports the execution of unmodified Java applications on both processing core types of the heterogeneous IBM Cell processor. An application's threads of execution can be transparently migrated between the Cell's different core types by Hera-JVM, without requiring the application's involvement. A number of real-world Java benchmarks are executed across both of the Cell's core types, to evaluate the efficacy of abstracting a heterogeneous architecture behind a homogeneous virtual machine. By characterising the performance of each of the Cell processor's core types under different program behaviours, a set of influential program behaviour characteristics is uncovered. A set of code annotations are presented, which enable program code to be tagged with these behaviour characteristics, enabling a runtime system to track a program's behaviour throughout its execution. This information is fed into a cost function, which Hera-JVM uses to automatically estimate whether the executing program's threads of execution would benefit from being migrated to a different core type, given their current behaviour characteristics. The use of history, hysteresis and trend tracking, by this cost function, is explored as a means of increasing its stability and limiting detrimental thread migrations. The effectiveness of a number of different migration strategies is also investigated under real-world Java benchmarks, with the most effective found to be a strategy that can target code, such that a thread is migrated whenever it executes this code. This dissertation also investigates the use of runtime monitoring to enable a runtime system to automatically infer a program's behaviour characteristics, without the need for explicit code annotations. A lightweight runtime behaviour monitoring system is developed, and its effectiveness at choosing the most appropriate core type on which to execute a set of real-world Java benchmarks is examined. Combining explicit behaviour characteristic annotations with those characteristics which are monitored at runtime is also explored. Finally, an initial investigation is performed into the use of behaviour characteristics to improve application performance under a different type of heterogeneous architecture, specifically, a non-uniform memory access (NUMA) architecture. Thread teams are proposed as a method of automatically clustering communicating threads onto the same NUMA node, thereby reducing data access overheads. Evaluation of this approach shows that it is effective at improving application performance, if the application's threads can be partitioned across the available NUMA nodes of a system. The findings of this work demonstrate that a runtime system with a homogeneous virtual machine interface can reduce the challenge of application development for HMA processors, whilst still being able to exploit such a processor by taking program behaviour into account

Information Economics and Chemical Toxicity: Designing Laws to Produce and Use Data

Just as laws may create entitlements to the use of information, they may also be written to distribute information and to encourage information production. This Article discusses the ways in which law affects the generation and distribution of information related to chemical exposure and toxicity. It describes the economic impact of recently enacted right-to-know laws and proposes that better and more abundant data could be produced if the law paid greater attention to basic economic principles that influence research and information systems

Exploring the Complexity and Controversy of Code-switching Practices In the EFL and EMI Classrooms at a Higher Education Institute in the Sultanate of Oman

The purpose of this study is to gain a comprehensive understanding of the usage of code-switching (CS), from English to Arabic, in bilingual classrooms (EFL and EMI) at a higher education institute in Oman, as well as to explore the complexity and controversy surrounding its use by teachers and students. The research questions focused on how CS is specifically applied in EFL, and EMI classrooms where English is the medium of instruction, the extent to which it exists, who uses it, why, for what functions, and its consequences. Furthermore, the study looks into how EFL and EMI teachers and students feel about using CS in the classroom. Six public college classes, three EFL and three EMI took part in this study, as well as the six teachers who taught these classes. The methods of data collection and analysis were based on the interpretive paradigm. Data were triangulated, which means it was acquired from various sources which comprised six classroom observations, six video recordings of the participant classes, six focus group interviews with students, and six stimulated semi-structured interviews with participant teachers all of which were recorded. Thematic analysis was used to examine and analyse the data collected, in addition, the number of CS occurrences encountered by participant teachers and their students during the participant EFL, and EMI classes were counted. According to the findings of the study, CS is a commonly employed strategy by teachers and students during the EFL and EMI classrooms despite the debate surrounding its usage. The three types of CS were present in the participant classrooms: Intersentential, intrasentential, and tag-switching. Furthermore, data demonstrated that CS is used for a variety of pedagogical, social, and affective functions. Additionally, both participants; teachers, and their students reported several reasons for using CS. Furthermore, they viewed CS as a supportive strategy that assists students in their learning as well as teachers in their delivery of lessons. Participants also had positive attitudes towards its usage in their classrooms. Nonetheless, they were cautious to employ it and expressed a number of concerns. Comparisons between EFL classrooms and EMI classrooms were made where applicable, and it was found that participants' responses to some CS aspects vary depending on the context. Teachers of EFL students, for example, reported that they employ CS to increase student involvement/participation in class and to assist low-level students. These reasons, however, were not acknowledged by EMI participant’ teachers. Instead, they mentioned two different reasons: to connect students' prior understanding of course topics to the new ones and to assist students in transitioning from studying in Arabic in high school to learning in English in college. Nevertheless, the responses of EFL and EMI participant teachers were sometimes similar. For example, they both stated that they use CS in their classes to help their students understand/ understand more, to fulfil students' various needs/abilities, and to get their students' attention to what their teacher is saying. This comparison applies throughout this study to the responses of participant teachers and students to the various CS aspects that were investigated. Furthermore, this study uncovered a number of intriguing findings on the use of CS in EFL and EMI classes. First, there is a relationship between code-switching, the class pace, and the flow of students’ responses: EMI classes as an example. Second, CS supports the cognitive dimension of students’ learning. Third, there is a connection/interaction between religion, specifically Islam in this context and language usage in the classroom. This finding inspired the researcher to coin a new CS dimension: religious code-switching/religion-related code-switching. Fourth, CS has a positive affective influence on students to learn in the classroom. Fifth, in both contexts, EFL and EMI, CS appeared to be an essential key component during group work discussions. Sixth, as EMI participant teachers claim, oral CS in the classroom causes students to switch codes and use Arabic words and phrases in their answers when writing their exams. Finally, the study's findings highlighted the significance of nonverbal communication between teachers and their students during their classes

Closing the loop: engaging with clinical outcomes in routine evaluation data

This work based project concerns the use of the CORE PC system within the Adur, Arun and Worthing Primary Care Counselling Service, which I manage. The system has been in use for 3 years and is currently used by some 200 services nationally. My objectives in this project were to establish and critically examine the use of CORE data within the service, ensuring that data collected is reflected on to inform clinical practice. This is a very broad study of a previously unexplored area, and I have therefore taken a broad-brush approach. Using a methodology influenced by action research, and to a lesser extent the case study approach, I examine the process of feeding back and critically reflecting on the data produced to inform our clinical practice. I also reflect on the introduction and management of the system. Evidence is presented from action reflection cycles as well as focus groups and a questionnaire given to counsellors. There are a number of outcomes to this project: I conclude that, notwithstanding the limitations of the instrument, CORE-PC can be used and experienced as useful in clinical practice by both counsellors and service managers. A tool such as CORE cannot be simply taken off the shelf and used uncritically however. We need to carefully attend to and manage the process of introducing and using CORE to ensure that the data is used in a thoughtful and sophisticated manner to inform our practice. I further conclude that making significant use of CORE (or any other audit data) and to extend its potential, has major implications for the culture of a service. We need to manage the process of introduction and use in order to encourage an environment where we can engage in critical discussions regarding the meaning and implications of the data. Attention to process is critical. There is a tension at the heart of using CORE between its use as a performance management tool and its use as a developmental tool. This tension needs to be acknowledged and worked with rather than ignored. CORE PC allows for the creation of individual as well as service wide data. This brings many potential benefits and difficulties as we begin to develop the capacity to look behind the consulting room door at how any individual clinician is performing. If we are to really generate meaning from our data we need to be examining it in clinical supervision. This service is in the vanguard of making critical and sophisticated use of the data provided. Three themes are identified as important in creating the kind of learning organisation where CORE data can be engaged with and used to generate useful knowledge. These are leadership, especially in attending to the process of introducing CORE and interpreting data correctly, ownership and relationship

Exploring curriculum policy-practice gaps in Jamaica: learning from policymakers, principals and teachers

This study highlights the relationship between curriculum policy intention and enactment. It considered the gap between the design of the National Standards Curriculum (NSC) in Jamaica and its enactment in a sample of twenty schools. The aim is to inform a real-world understanding of the expectations of curriculum policymakers and principals, and teachers as curriculum enactors. The study utilises a qualitative methodology with thematic analysis. Data were collected using secondary and primary sources. Secondary sources included published and unpublished reports, desk reviews and my professional knowledge of Jamaica's public education system. Primary sources were lesson observations and policymaker and practitioner interviews. The participants were seven key Ministry of Education and Youth Policymakers, twenty school principals and twenty classroom teachers who implemented the NSC. The theoretical framework includes Blumer's symbolic interactionism, globalisation and education reform, learner-centred pedagogy, social and sociocultural constructivism, Freire's critical pedagogy, curriculum enactment and Elbaz's theory of teachers' practical knowledge. The research provides a means for the participants to contribute a contextual understanding of the possible pitfalls of implementing a globally inspired curriculum policy in a small developing state with post-colonial antecedents and significant resource constraints. Generally, policymakers were unsophisticated in their policy expectations for the NSC. The principals view themselves as extensions of the MOEY, diminishing their role in enacting the NSC. Both policymakers and principals failed to recognise teachers' practical knowledge and support for the NSC. Their failure creates further dissonance between the NSC as a policy and its enactment in the classroom. However, teachers bear some responsibility for the inertia in enacting the NSC. This failure is partially due to a skill and knowledge deficit, which policymakers and principals should work together to address. Finally, this study adds to the available literature on education policy-practice gaps, illustrates this phenomenon of global curriculum reform movements in a small Caribbean state and reinforces the intrinsic value of engaging in real-world research to understand and solve complex problems

An Assessment of Impact Metrics’ Potential as Research Indicators Based on Their Perception, Usage, and Dependencies from External Science Communication

The demand for practicable methods for quantitative assessments of scientific products’ relevance has risen considerably over the past decades. As a consequence, research and commercial providers of scholarly data developed a wide variety of impact indicators, ranging from citation-based to so-called altmetrics. This highly heterogeneous family of indicators is based on the principle of measuring interactions with scientific publications that are observable online, and covers for instance mentions of publications in social and journalistic media, in literature management software, or in policy documents. The various metrics' theoretical validity as impact indicators is debated constantly, as questions regarding what it is that different metrics measure or express in many facets remain unanswered. This thesis makes two central contributions towards answering these questions. Its first part systematically assesses the status quo of various metrics’ perception and usage by researchers. This assessment serves to determine the significance of metrics in academic daily routines, as well as to identify relevant perceived problems concerning their usage. The challenges identified this way are in later sections of the thesis opposed with concrete measures to be taken during the development of future research metrics and their infrastructure to effectively solve common criticisms regarding current metrics and their use. Proceeding from the first part’s user studies, this thesis’ second part examines the relationship between research metrics and external science communication. It this way addresses a wide research gap with considerable potential implications for metrics’ validity as indicators for quality - the question to which degree these metrics are merely the result of promotion, which respective research publications receive

Past as prologue : the Royal Commission into Commercial Activities of Government and Other Matters : proceedings from a conference on the Part II Report of the Royal Commission and the reform of government in Western Australia

The Royal Commission into the Commercial Activities of Government and Other Matters was appointed by the Lawrence Government on the 8th January 1991. The Commission concluded its work in November 1992, producing two major reports on the conduct of government in Western Australia between 1983 and 1989. In the second of these reports, the Commission made forty separate recommendations for the reform of Western Australian Government, to be implemented by a Commission on Government. This conference examines the legacy of the Royal Commission, the work of the Commission on Government and issues in the reform or \u27re-invention\u27 of government. The conference concludes with presentations from the current generation of political decision makers on the reforming of government and the role of the media in the work of the Royal Commission

Software test and evaluation study phase I and II : survey and analysis

Issued as Final report, Project no. G-36-661 (continues G-36-636; includes A-2568