• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 140
  • 21
  • 21
  • 13
  • 8
  • 7
  • 6
  • 6
  • 5
  • 3
  • 2
  • 2
  • 2
  • 2
  • 1
  • Tagged with
  • 268
  • 268
  • 168
  • 55
  • 38
  • 33
  • 31
  • 30
  • 26
  • 24
  • 22
  • 22
  • 21
  • 21
  • 21
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
111

Exploring Cyber Ranges in Cybersecurity Education

Beauchamp, Cheryl Lynn 01 April 2022 (has links)
According to a report from McAfee, the global cost of cybercrime for 2020 was over one trillion dollars (Smith, Z. et al., 2020). Cybersecurity breaches and attacks have not only cost businesses and organizations millions of dollars but have also threatened national security and critical infrastructure. Examples include the Ransomware attack in May of 2021 on the largest fuel pipeline in the United States and the February 2021 remote access system breach of a Florida water treatment facility which raised sodium hydroxide to a lethal level. Improving cybersecurity requires a skilled workforce with relevant knowledge and skills. Academic degree programs, boot camps, and various certification programs provide education and training to assist this need. Cyber ranges are a more recent development to provide hands-on skill training. These ranges, often virtual, provide a safe and accessible environment to improve practical skills and experience through hands-on application. They provide a training environment to identify threats, apply countermeasures, and secure data from risks separately from the organization's actual network. More and more academic programs utilize cyber ranges due to the perceived benefit of integrating them into their cybersecurity-related programs. Academic cyber ranges offer virtualized environments that support cybersecurity educators' needs to provide students with a safe, separated, and engaging environment. The purpose of my research has two components: 1) to understand who the educators are using academic-facing cyber ranges and how they are using them to support their cybersecurity education efforts, and 2) to understand how cybersecurity educators and students are motivated by using them. Specifically, my research is comprised of three manuscripts: (1) a mixed-method exploratory study of who are the educators using cyber ranges for cybersecurity education and how they are using them to create significant cybersecurity learning experiences, (2) a mixed-method study exploring the motivation of educators using a cyber range for cybersecurity education, and (3) a mixed-method study exploring student motivation participating in cybersecurity CTF competitions. The three manuscripts contribute to understanding cyber ranges in cybersecurity education. The results from my research provided insight from the users of these cyber ranges, cybersecurity educators and students. Results from my first manuscript suggested that high school cybersecurity educators are the primary users. These educators have less formal cybersecurity education and experience compared to cybersecurity educators in higher education. The data also showed that cybersecurity educators primarily used cyber ranges for teaching and learning to meet learning goals and objectives. Results from my second manuscript suggested that educators were motivated mainly by the importance of using a cyber range for cybersecurity education and for the interest-enjoyment their students experience from cyber range usage. Educators found using the cyber range made their class more engaging and relevant to their students.These educators were also confident they could use a cyber range and learn how to use it. However, those without prior experience in cybersecurity or previous experience using a cyber range shared they needed instructor-facing resources, professional development opportunities, and time to learn. Results from my third manuscript suggested that students were motivated by the importance of participating in a cybersecurity CTF competition. Many reported that participating was useful for developing professional skills and readiness. Although CTF competitions were considered difficult and stressful, students did not consider the difficulty pejorative. Many shared that challenging CTFs contributed towards the enjoyment of participating, making them a rewarding and worthwhile experience. However, students also shared that academic and team support contributed towards their confidence in competing. In contrast, those who did not report confidence, stated they lacked a team strategy or support from their academic institution. Additionally, they did not know what to expect to prepare before the competition event. Overall, the results of this dissertation highlight the importance of prior preparation for educators and student CTF participants. For educators, this prior preparation includes curriculum supporting resources such as content mapping to learning objectives and professional development opportunities that do not assume any prior knowledge or experience. For students, prior preparation includes understanding what to expect and recommendations for academic and team support. / Doctor of Philosophy / The technology era has enabled a global connectedness to attend conferences and meetings via our laptop computers while working from home. The proliferation of smart devices has also provided a means to view and communicate with visitors who ring our smart doorbells while we are not home. This interconnected network, i.e., the Internet, has altered how we pay our bills, buy our groceries, and attend classes virtually. It has also enabled cyber attacks and breaches that have contributed to identity thefts, increasing financial costs, business collapses, job losses, and even threatened national security. A cybersecurity workforce has become increasingly vital to address the need for improving cybersecurity. Thus, there is a need for academic cybersecurity programs to prepare future professionals to fill this national workforce shortfall. Consequently, more and more organizations have integrated cyber ranges as the means to provide a simulated environment for applying and developing cybersecurity-related knowledge and skills. Similar to a driving range for a golfer to practice their golf swing or a shooting range for those in law enforcement to earn their firearms qualifications, a cyber range supports efforts to provide cybersecurity training with hands-on exercises and labs to practice skills in a safe, virtual environment. My research contributes to understanding who uses cyber ranges and how they are motivated to use them for cybersecurity education. The first purpose of my research was to understand the educators who were using cyber ranges and how they were using them for cybersecurity education. More specifically, I examined their usage for alignment with a learning taxonomy to verify the usage contributed to successful and significant student learning. This understanding contributed to my research's second purpose, which explored how educators were motivated using cyber ranges. The third purpose of my study explored student motivation using a cyber range. Due to varying cyber range resources and activities, my research focused on the cybersecurity competition activity, Capture the Flag (CTF). This study provided an understanding of how students who participated in a cybersecurity CTF competition were motivated. My research demonstrates that educators and students are interested in using cyber ranges and believe using them for cybersecurity education and professional readiness is important. However, both educators and students who lack prior knowledge or experience using a cyber range or participating in a CTF shared the concern of not knowing what they do not know. PD time and instructor-facing resources that do not assume any prior cybersecurity knowledge were recommended to support educators who did not have a background or experience in cybersecurity. Students shared that although not knowing was stressful and made participating difficult, the difficulty and stress were good attributes because if the CTF were easy, it wouldn't be worth their time and would be less rewarding. Students also reported that team strategies and academic support were motivational aspects of CTF participation. Overall, educators and students were motivated using cyber ranges for cybersecurity education, but professional development and preparation resources would contribute positively to their usage.
112

MOTIVATIONAL CHARACTERISTICS OF K-12 TEACHERS: DETERMINING THE VALUES THAT INFLUENCE PRE-SERVICE TEACHERS’ DECISION TO TEACH

Torsney, Benjamin January 2016 (has links)
This study examined the motivations pre-service teachers possess as they progress though a teacher education program. Using Watt and Richardson’s (2007) Factors Influencing Teaching Choice (FIT-Choice) model as the theoretical underpinnings, the following research questions set the foundation for this study: 1) Do pre-service teachers’ motivation to pursue a teaching career change over the course of a teacher education program, and 2) Is there a relationship between pre-service teachers’ values and their satisfaction with their choice to pursue a teaching career? Quantitative results indicate significant drops in motivation from students’ Freshman/Sophomore year to students’ Graduate year. Qualitative results demonstrated a greater frequency of responses for social utility values, intrinsic motivation, positive prior teaching and learning experiences, career development aspirations, and epistemic values. / Educational Psychology
113

Examining the Interrelationship of Motivation and Place Attachment in a Residential 4-H Camping Environment

Genson, Jenna McEwen 12 May 2010 (has links)
Minimal research has examined the interrelationship between motivation, place attachment, and the need to belong in a residential camping environment. The purpose of this study was to better understand the role of place attachment and the need to belong in facilitating 4-H Camp Graham campers and counselors interest in returning to residential 4-H summer camp year after year. All participants included in this study were at least 18 years of age, graduated from high school, former 4-H members, and attended 4-H camp for at least two consecutive years. Three camping clusters participated in focus group interviews for a total of 21 participants. A fourth camping cluster and participants unable to attend their designated focus group, were invited complete an online survey. Overall, campers and counselors were primarily motivated to return to camp each year due to the relationships, memories, and sense of belonging formed at camp. While nature and location played a role in the camp experience by providing a secluded environment free from outside influence, these attachments were secondary. Attachment to camp grew over time and participants valued the camp experience highly and tended to choose camp friendships and the camp experience over other opportunities. Longevity at camp influenced the strength of attachment. This research suggests that intentionality in these areas of staff training and program planning are critical to camper and counselor connection to camp. Additionally, this research provides tangible evidence that points to the value of sharing the residential camping experience with potential funders and parents. / Master of Science in Life Sciences
114

<b>Developing Motivational Profiles of First-Year Engineering Students Using Latent Profile Analysis</b>

Alexander V Struck Jannini (19179625) 19 July 2024 (has links)
<p dir="ltr"><a href="" target="_blank">Improving student motivation and changing students from a negative motivational mindset to a positive one can be a viable way to ensure that students stay in their programs and obtain academic success. While educators and administrators are interested in improving motivation, they may not have the full body of knowledge about motivational theories and make uninformed classroom interventions and departmental policies. Using theory to understand student motivations grounds the research in specific constructs that allow educators and policymakers to easily interpret the results and make better-informed decisions regarding classroom activities and academic policies. Tying motivational mindsets to effective classroom behaviors and learning outcomes can help educators determine what motivational orientations are effective within the classroom, and which may need to be altered.</a></p><p dir="ltr">The work that I have done as part of this dissertation helps to advance the use of motivational theory within the field of engineering education and provides useful insight into the motivational mindsets of first-year engineering students. I conducted a latent profile analysis using data from engineering undergraduate students, combining constructs from two established motivational theories to develop motivational profiles. Using two theories, achievement goal theory and expectancy-value theory, allows me to look at the students’ motivational mindsets based on their expectations for success (Expectancy Beliefs), the perceived value of doing well in the course (Task Value Beliefs), their desire to develop their skills (Mastery Orientation), their desire to look well in front of their peers (Performance Approach Orientation), and their desire to not look bad in relation to others (Performance Avoidance Orientation). These five constructs were used to develop profiles, which were then correlated with classroom behaviors and academic performance to determine which motivational profiles were more effective. Correlational analysis was conducted using either ANOVA or Kruskal-Wallis tests, depending on the normality of the data.</p><p dir="ltr">The results of the latent profile analysis yielded five distinct profiles of motivation: <i>Moderate-Low All</i>, <i>Moderate-Low Performance/Moderate-High Intrinsic</i>, <i>Moderate All</i>, <i>High Performance/Moderate Intrinsic</i>, <i>and High All</i>. The <i>Moderate-Low All </i>profile consisted of students who reported lower measures of all motivation constructs than their peers. The <i>Moderate-Low Performance/Moderate-High Intrinsic</i> profile consisted of students who reported average responses related to Expectancy, Task-Value, and Mastery beliefs but scored lower in the Performance Approach and Performance Avoidance beliefs. The <i>Moderate All</i> profile was comprised of students who scored on average along all motivational constructs. The <i>High Performance/Moderate Intrinsic</i> profile contained students who reported average responses to Expectancy, Task-Value, and Mastery beliefs but scored higher in the Performance Approach and Performance Avoidance beliefs. The <i>High All</i> profile was comprised of students who scored higher than the average for all motivational constructs.</p><p dir="ltr">Students were asked to reflect on their use of specific classroom behaviors that were categorized based on the Interactive-Constructive-Active-Passive framework of educational activities. Correlational analysis showed that <i>Moderate-Low All</i> students reported using Passive, Constructive, and Interactive behaviors at a lower rate than their peers, especially <i>High All </i>students. Correlational analysis of academic performance measures also found that there were non-significant differences between profiles related to exam scores, but there were significant differences found in the final grades. <i>Moderate-Low All</i> students had lower final grades than the <i>Moderate-Low Performance/Moderate-High Intrinsic</i>, <i>Moderate All</i>, and <i>High All</i> groups.</p><p dir="ltr">These findings suggest that students in the <i>Moderate-Low All </i>profile are not doing worse in the class because of their exams, but due to not performing the other activities in the class. These activities include large group projects (Interactive tasks) and homework assignments (Constructive tasks). Considering the context of the study and the course that these students are taking, educational recommendations would be finding ways to incorporate more Constructive behaviors (i.e., reflection on their learning or making meaning from the material) into the course, as the class already has multiple Interactive tasks. Further research can also be done to investigate why students hold the views that they do, and whether this is an issue of perception or some other phenomenon.</p>
115

Exploring Contextually Relevant, Cognitively Demanding Mathematics Tasks: A Critical Ethnographic Inquiry Of The Instructional Practices And Beliefs Of Elementary Teachers Who Serve Economically Disadvantaged Students

Ruiz, Abigail 01 January 2024 (has links) (PDF)
This study explored teachers’ beliefs, values, and expectancies impacted their practices in relation to the intersection of contextually relevant and cognitively demanding elementary mathematics tasks. Using a critical ethnographic approach, the study examined the instructional practices and beliefs of elementary teachers serving this demographic. The study explored the characteristics of tasks that emerged when participants used a layered rubric approach, applying two rubrics to enhance cognitive demand and contextual relevance. It also investigated how teachers' expectancy-value beliefs, as outlined by the Expectancy Value Theory, influenced their application of these rubrics. Data were gathered through interviews, artifact analysis, and task evaluations. The findings revealed that Subjects' perceptions of the layered rubrics’ benefits and challenges influenced their task selection and modification processes. Subjects with asset-based beliefs followed the rubric guidelines and produced modified tasks that could enrich the mathematical experiences for students, characterized by heightened cognitive demand and contextual relevance. In contrast, those influenced by deficit-based beliefs deviated from the rubric guidelines, resulting in tasks that did not effectively enhance the desired task characteristics. This study contributes to the field of mathematics education by highlighting the profound impact of educators' beliefs on the quality of mathematics instruction for economically disadvantaged students. It offers recommendations for professional development focused on assessing teachers’ beliefs, values, and expectancies to promote asset-based views and facilitate sustainable, equitable mathematical practices through the application of a dual rubric approach.
116

Academic self-efficacy, achievement motivation, and academic success of international graduate students

Alzukari, Rawan 13 August 2024 (has links) (PDF)
This study examined academic self-efficacy, achievement motivation, and academic success among international graduate students at a large university in the southeastern United States. Specifically, the research focused on three dimensions of academic self-efficacy (i.e., English language self-efficacy, coursework self-efficacy, and social self-efficacy) and three dimensions of achievement motivation (i.e., intrinsic value, expectancy, and attainment utility) to determine their impact on academic success measured by academic satisfaction and academic achievement. Data were collected from 101 international graduate students who completed Questionnaire of English Self-Efficacy (QESE; Wang, 2004); the College Self-Efficacy Inventory (CSEI; Solberg et al., 1993); the Expectancy-Value Motivation Questionnaire (EVMQ; Hagemeier & Newton 2010); the Academic Life Satisfaction Scale (ALSS; Kumar & Dilip, 2005); and the Subjective Academic Achievement Scale (SAAS; Stadler, Kemper & Greiff, 2021). Findings reveal strong positive correlations among the dimensions of academic self-efficacy. Intrinsic motivation and attainment utility significantly predicted academic satisfaction, while expectancy beliefs were crucial for academic achievement. Coursework self-efficacy emerged as a significant predictor of both academic satisfaction and academic achievement, highlighting its importance. In contrast, social self-efficacy did not significantly impact academic outcomes. These results suggest that enhancing international students’ self-efficacy, especially in coursework and English language proficiency, can improve their academic satisfaction and achievement. The study highlights the complex roles of academic self-efficacy and achievement motivation in academic success, offering insights to encourage higher education stakeholders to better support international students and create a more inclusive educational environment.
117

Formativ bedömning : en enkel match eller en svår utmaning? Effekter av en kompetensutvecklingssatsning på lärarnas praktik och på elevernas prestationer i matematik / Formative assessment : a piece of cake or a difficult challenge? Effects of a professional development programme on teachers' classroom practice and students' achievement in mathematics

Boström, Erika January 2017 (has links)
Research reviews have shown that the use of formative assessment in classroom practice can substantially improve student achievement. However, a strong research base about how to support teachers’ implementation of such formative classroom practice is lacking. In this thesis, I investigate the effects of a comprehensive professional development programme (PDP) in formative assessment on teachers’ classroom practice and students’ achievement in mathematics. In addition, I identify reasons for the changes made in the teachers’ formative classroom practice. Fourteen randomly selected year - 7 mathematics teachers participated in the PDP. The teachers’ formative classroom practice before and after attending the programme was analysed and described, and reasons for their change in practice were explored. The effect of the changes in formative classroom practice on students’ mathematics achievement was examined using pre- and post-tests administered to both the intervention group and a control group. A mixed methods approach with classroom observations, teacher interviews, questionnaires and student achievement tests in mathematics was used in the studies included in the thesis. The results show that the teachers used aspects of formative assessment in their classroom practice before the PDP, but that there was plenty of room for development towards a more effective formative assessment practice. Several possibilities for developing the practice were identified. After the PDP the teachers believed in the idea of formative assessment and were motivated to make changes towards a more formative classroom practice. The teachers included new formative assessment activities in their classroom practice, but in different ways and to different degrees. The characteristics of these changes were identified, and also the characteristics of the PDP that the teachers found to be influential for their development of the formative classroom practice. Results also show that the teachers’ motivational beliefs held after the PDP was an explanatory factor for their changes in practice. However, the formative assessment practice the teachers implemented did not have a significant effect on their students’ achievement compared to the control group. In addition, there was no correlation between the number of formative assessment activities implemented by the teachers and their students’ achievement gains. Reasons for these non-effects on student achievement, and for the teachers’ degree and type of implementation of formative assessment in the classroom practice, are discussed in the thesis.
118

Development of value at risk measures : towards an extreme value approach

Ganief, Moegamad Shahiem 12 1900 (has links)
Thesis (MBA)--Stellenbosch University, 2001. / ENGLISH ABSTRACT: Commercial banks, investment banks, insurance companies, non-financial firms, and pension funds hold portfolios of assets that may include stocks, bonds, currencies, and derivatives. Each institution needs to quantify the amount of risk its portfolio is exposed to in the course of a day, week, month, or year. Extreme events in financial markets, such as the stock market crash of October 1987, are central issues in finance and particularly in risk management and financial regulation. A method called value at risk (VaR) can be used to estimate market risk. Value at risk is a powerful measure of risk that is gaining wide acceptance amongst institutions for the management of market risk. Value at Risk is an estimate of the largest lost that a portfolio is likely to suffer during all but truly exceptional periods. More precisely, the VaR is the maximum loss that an institution can be confident it would lose a certain fraction of the time over a particular period. The power of the concept is its generality. VaR measures are applicable to entire portfolios - encompassing many asset categories and multiple sources of risk. As with its power, the challenge of calculating VaR also stems from its generality. In order to measure risk in a portfolio using VaR, some means must be found for determining a return distribution for the portfolio. There exists a wide range of literature on different methods of implementing VaR. But, when one attempts to apply the results, several questions remain open. For example, given a VaR measure, how can the risk manager test that the particular measure at hand is appropriately specified? And secondly, given two different VaR measures, how can the risk manager pick the best measure? Despite the popularity of VaR for measuring market risk, no consensus has yet been reach as to the best method to implement this risk measure. The absence of consensus is in part derived from the realization that each method currently in use has some significant drawbacks. The aim of this project is threefold: to introduce the reader to the concept of VaR; present the theoretical basis for the general approaches to VaR computations; and to introduce and apply Extreme Value Theory to VaR calculations. The general approaches to VaR computation falls into three categories, namely, Analytic (Parametric) Approach, Historical Simulation Approach, and Monte Carlo Simulation Approach. Each of these approaches has its strengths and weaknesses, which will study more closely. The extreme value approach to VaR calculation is a relatively new approach. Since most observed returns are central ones, traditional VaR methods tend to ignore extreme events and focus on risk measures that accommodate the whole empirical distribution of central returns. The danger of this approach is that these models are prone to fail just when they are needed most - in large market moves, when institutions can suffer very large losses. The extreme value approach is a tool that attempts to provide the user with the best possible estimate of the tail area of the distribution. Even in the absence of useful historical data, extreme value theory provides guidance on the kind of distribution that should be selected so that extreme risks are handled conservatively. As an illustration, the extreme value method will be applied to a foreign exchange futures contract. The validity of EVT to VaR calculations will be tested by examining the data of the Rand/Dollar One Year Futures Contracts. An extended worked example will be provided wherein which attempts to highlight the considerable strengths of the methods as well as the pitfalls and limitations. These results will be compared to VaR measures calculated using a GARCH(l,l) model. / AFRIKAANSE OPSOMMING: Handelsbanke, aksepbanke, assuransiemaatskappye, nie-finansiële instellings en pensioenfondse beskik oor portefeuljes van finansiële bates soos aandele, effekte, geldeenhede en afgeleides. Elke instelling moet die omvang kan bepaal van die risiko waaraan die portefeulje blootgestel is in die loop van 'n dag, week, maand of jaar. Uitsonderlike gebeure op finansiële markte, soos die ineenstorting van die aandelemark in Oktober 1987, is van besondere belang vir finansies en veral vir risikobestuur en finansiële regulering. 'n Metode wat genoem word Waarde op Risiko (WoR), kan gebruik word om markverliese te meet. WoR is 'n kragtige maatstaf vir risiko en word deur vele instellings gebruik vir die bestuur van mark-risiko. Waarde op Risiko is 'n raming van die grootste verlies wat 'n portefeulje moontlik kan ly gedurende enige tydperk, met uitsluiting van werklik uitsonderlike tydperke. Van nader beskou, is WoR die maksimum verlies wat 'n instelling kan verwag om gedurende 'n sekere tydperk binne 'n bepaalde periode te ly. Die waarde van die konsep lê in die algemene aard daarvan. WoR metings is van toepassing op portefeuljes in dié geheel en dit omvat baie kategorieë bates en veelvuldige bronne van risiko. Soos met die waarde van die konsep, hou die uitdaging om WoR te bereken ook verband met die algemene aard van die konsep. Ten einde die risiko te bepaal in 'n portefeulje waar WoR gebruik word, moet metodes gevind word waarvolgens 'n opbrengsverdeling vir die portefeulje vasgestel kan word. Daar bestaan 'n groot verskeidenheid literatuur oor die verskillende metodes om WoR te implementeer. Wanneer dit egter kom by die toepassing van die resultate, bly verskeie vrae onbeantwoord. Byvoorbeeld, hoe kan die risikobestuurder aan die hand van 'n gegewe WoR-maatstaf toets of die spesifieke maatstaf reg gespesifiseer is? Tweedens, hoe kan die risikobestuurder die beste maatstaf kies in die geval van twee verskillende WoR-maatstawwe? Ondanks die feit dat WoR algemeen gebruik word vir die meting van markrisiko, is daar nog nie konsensus bereik oor die beste metode om hierdie benadering tot risikometing te implementeer nie. Die feit dat daar nie konsensus bestaan nie, kan deels daaraan toegeskryf word dat elkeen van die metodes wat tans gebruik word, ernstige leemtes het. Die doel van hierdie projek is om die konsep WoR bekend te stel, om die teoretiese grondslag te lê vir die algemene benadering tot die berekening van WoR en om die Ekstreme Waarde-teorie bekend te stel en toe te pas op WoR-berekenings. Die algemene benadering tot die berekening van WoR word in drie kategorieë verdeel naamlik die Analitiese (Parametriese) benadering, die Historiese simulasiebenadering en die Monte Carlo-simulasiebenadering. Elkeen van die benaderings het sterk- en swakpunte wat van nader ondersoek sal word. Die Ekstreme Waarde-benadering tot WoR is 'n relatief nuwe benadering. Aangesien die meeste opbrengste middelwaarde-gesentreer is, is tradisionele WoR-metodes geneig om uitsonderlike gebeure buite rekening te laat en te fokus op risiko-maatstawwe wat die hele empiriese verdeling van middelwaarde-gesentreerde opbrengste akkommodeer. Die gevaar bestaan dan dat hierdie modelle geneig is om te faal juis wanneer dit die meeste benodig word, byvoorbeeld in die geval van groot markverskuiwings waartydens organisasies baie groot verliese kan ly. Daar word beoog om met behulp van die Ekstreme Waarde-benadering aan die gebruiker die beste moontlike skatting van die stert-area van die verdeling te gee. Selfs in die afwesigheid van bruikbare historiese data verskaf die Ekstreme Waarde-teorie riglyne ten opsigte van die aard van die verdeling wat gekies moet word, sodat uiterste risiko's versigtig hanteer kan word. Ten einde hierdie metode te illustreer, word dit in hierdie studie toegepas op 'n termynkontrak ten opsigte van buitelandse wisselkoerse. Die geldigheid van die Ekstreme Waarde-teorie ten opsigte van WoR berekenings word getoets deur die data van die Rand/Dollar Eenjaartermynkontrak te bestudeer. 'n Volledig uitgewerkte voorbeeld word verskaf waarin die slaggate en beperkings asook die talle sterkpunte van die model uitgewys word. Hierdie resultate sal vergelyk word met 'n WoR-meting wat bereken is met die GARCH (1,1) model.
119

An Empirical Development of Critical Value Factors for System Quality and Information Quality in Business Intelligence Systems Implementations

Dooley, Paul 01 May 2015 (has links)
Business intelligence (BI) systems have been widely recognized as a leading technology for many years. However, despite the high priority and importance placed on BI, there has been a significant lack of BI system implementation (BISI) success. BI systems are not considered to be conventional information systems (IS) and often rely on the integration of a complex information infrastructure. Consequently, the degree of information quality (IQ) and system quality (SQ) have not met expectations for BISI success. This study was designed to determine how an organization may gain benefits in the context of BISI by uncovering the antecedents and critical value factors (CVFs) of SQ and IQ necessary to derive greater BISI success. In phase one, a list of BISI SQ and IQ characteristics were collected through literature discovery and an open-ended questionnaire delivered to a group of BI user experts. The collected items were grouped and categorized based on their similarities. In phase two of the study 257 survey responses were collected from BI users to measure the level of importance, i.e. value, they placed on SQ and IQ characteristics. Exploratory factor analysis (EFA) via principal component analysis (PCA) was then used to uncover the CVFs of SQ and IQ that influence BISI success. Two highly reliable CVFs for SQ of BISI with a cumulative variance of nearly 62% and three highly reliable CVFs for IQ of BISI with a cumulative variance of over 75% were subsequently identified. In phase three of the study, an extended conceptual model for IS success was validated to assess the uncovered CVFs of SQ and IQ, as well as their influence on the constructs of perceived SQ of BISI and perceived IQ of BISI. Employing partial least squares (PLS), a subset of structural equation modeling (SEM), the research model was then used to assess the dimensions of perceived SQ of BISI and perceived IQ of BISI as antecedents of the constructs of perceived user systems satisfaction and perceived user information satisfaction from BISI. The crossover effects of perceived user systems and information satisfaction from BISI were also analyzed. The results identified two SQ CVFs of BISI (integration flexibility SQ and reliability SQ) that demonstrated a significant positive impact on perceived SQ for BISI as well as three IQ CVFs of BISI (representation IQ, intrinsic IQ, and accessibility IQ) that had a significant positive impact on perceived IQ of BISI. The constructs of perceived user systems satisfaction and perceived user information satisfaction from BISI had explained variances of R2 = .576 and .589 respectively. Additionally, 12 items of SQ for BISI and 14 items of IQ for BISI were identified as possessing high reliability. This study makes two important contributions to the IS body of knowledge. First, it investigated the universal set of antecedents of SQ and IQ to establish the CVFs of IQ (integration flexibility SQ and reliability SQ) as well as the CVFs of IQ (representation IQ, intrinsic IQ, and accessibility IQ) for BISI success. Second, this study evaluated the crossover effects of system and information satisfaction in BISI success highlighting the importance that BI users place on the need to distinguish between the BI system, the IQ of the output produced, and the influence of IQ on perceived user system satisfaction from BISI. This study benefits stakeholders by focusing on what is important to BISI success and identifies those areas that are most likely to lead to better use of scarce resources while providing the greatest benefits.
120

'n Ondersoek na die eindige steekproefgedrag van inferensiemetodes in ekstreemwaarde-teorie

Van Deventer, Dewald 03 1900 (has links)
Thesis (MComm (Statistics and Actuarial Science))--University of Stellenbosch, 2005. / Extremes are unusual or rare events. However, when such events – for example earthquakes, tidal waves and market crashes - do take place, they typically cause enormous losses, both in terms of human lives and monetary value. For this reason, it is of critical importance to accurately model extremal events. Extreme value theory entails the development of statistical models and techniques in order to describe and model such rare observations. In this document we discuss aspects of extreme value theory. This theory consists of two approaches: The classical maxima method, based on the properties of the maximum of a sample and the more popular threshold theory, based upon the properties of exceedances of a specified threshold value. This document provides the practitioner with the theoretical and practical tools for both these approaches. This will enable him/her to perform extreme value analyses with confidence. Extreme value theory – for both approaches - is based upon asymptotic arguments. For finite samples, the limiting result for the sample maximum holds approximately only. Similarly, for finite choices of the threshold, the limiting distribution for exceedances of that threshold holds only approximately. In this document we investigate the quality of extreme value based inferences with regard to the unknown underlying distribution when the sample size or threshold is finite. Estimation of extreme tail quantiles of the underlying distribution, as well as the calculation of confidence intervals, are typically the most important objectives of an extreme analysis. For that reason, we evaluate the accuracy of extreme based inferences in terms of these estimates. This investigation was carried out using a simulation study, performed with the software package S-Plus.

Page generated in 0.0677 seconds