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  • 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.
321

A convergent reformulation of perturbative QCD

Alves, Ricardo Joao Gaio January 2000 (has links)
We present and explore a new formulation of perturbative QCD based not on the renormalised coupling but on the dimensional transmutation parameter of the theory and the property of asymptotic scaling. The approach yields a continued function, the iterated function being that involved in the solution of the two-loop β-function equation. In the so-called large-b limit the continued function reduces to a continued fraction and the successive approximants are diagonal Padé approximants. We investigate numerically the convergence of successive approximants using the leading-b approximation, motivated by renormalons, to model the all-orders result. We consider the Adler D-function of vacuum polarisation, the Polarised Bjorken and Gross-Llewellyn Smith sum rules, the (unpolarised) Bjorken sum rule, and the Minkowskian quantities R(_r) and the R-ratio of e(^+)e(^-) annihilation. In contrast to diagonal Fade approximants the truncated continued function method gives remarkably stable large-order approximants in cases where infra-red renormalon effects are important. We also use the new approach to determine the QCD fundamental parameters from the R(_r) and the R-ratio measurements, where we find Ā(^(3))(_MS)=516±48 MeV (which yields a(_s)(µ=m(_r))=0.360(^+0.021)(_=0.020)), and Ā(^(5))(_MS)=299(^+6)(_-7) MeV (which yields a(_s)(µ=m(_zo)=0.1218±0.0004), respectively. The evolution of the former value to the m(_zo) energy results in a(_s)(µ= m(_zo)) = 0.123 ± 0.002. These values are in line with other determinations available in the literature. We implement the Complete Renormalisation Group Improvement (CORGI) scheme throughout all the calculations. We report on how the mathematical concept of Stieltjes series can be used to assess the convergence of Padé approximants of perturbative series. We find that the combinations of UV renormalons which occur in perturbative QCD may or may not be Stieltjes series depending on the renormalisation scheme used.
322

Exploiting the Gaps in GAAP: A Look at the Principles Versus Rules Debate

Gillette, Nicholas A. 01 January 2013 (has links)
The principles versus rules debate has long since been a conversation in the accounting world, but the conversation heated up in the early part of the 21st century on the heels of a few highly publicized accounting frauds. In an increasingly globalized business environment, convergence between the more rules-oriented US GAAP and more principles-oriented IFRS is becoming more and more relevant. This study attempts to better inform that debate, exploring the accounting conceptual framework, United States legal environment, and the costs and benefits of adopting a more principles-oriented set of accounting standards. This study concludes that, though there would likely be some costs initially, principles-oriented standards give managers the ability to produce more relevant, comparable, and reliable financial statements, and can even serve to deincentivize fraudulent behavior. By adjusting the incentive structure, managers would no longer be offered protection by bright-line rules, instead required to more faithfully represent the economic reality of their firm. However, though rules-oriented standards like lease accounting are in need of improvement, due to the complex nature of some transactions, not all standards can be solely principles-oriented. As such, the FASB should develop a propensity away from rules, detailed guidance, and exceptions whenever possible.
323

Elektroninių aukcionų kūrimas / Development of e-auctions

Zelenkauskas, Artūras 09 July 2011 (has links)
. Informacinės technologijos, tokios kaip Internetas ir elektroninė komercija, radikaliai pakeitė būdus, kaip keistis informacija ar vykdyti įvairius atsiskaitymus. Sparčiai besivystančios informacinės technologijos neaplenkė ir verslo, kuriam suteikė naujų galimybių didinant konkurencingumą. Per pastaruosius keletą metų ypač išpopuliarėjo elektroninės komercijos šaka – elektroniniai aukcionai, kuri dar labiau paskatino verslą keltis į elektroninę erdvę. Aukciono valdymas yra sudėtingas. Vienas iš svarbiausių konkurencingumo veiksnių yra kaina, kuriai nustatyti įmonė taiko įvairias kainodaros taisykles. Aukcionas tai dinaminės kainodaros būdas, kuris leidžia įmonei ir klientui rasti pačią tinkamiausią sandorio kainą. Tinkamai valdydamos ir kaupdamos verslo taisykles, įmonės galėtų gauti didesnį pelną, greičiau parduoti turimas prekes. Elektroniniai aukcionai, paremti turinio valdymo principu ir norimų taisyklių sudarymu galėtų prisidėti prie verslo efektyvumo didinimo, t.y. kokiu būdu įmonės galėtų integruoti elektroninio aukciono metodą į savo informacines sistemas. Atlikta įvairių aukciono metodų teorinių veikimo principų analizė, kuri leido apibendrinti visus metodus, išskiriant ir palyginant pagrindines jų taisykles. Darbe atlikta sukurtų elektroninių aukcionų informacinių sistemų analizė ir jų kūrimo principai, kurie leido apibendrinti pagrindines naudojamas taisykles. Atliktas eksperimentinis tyrimas, kurio metu koreliacinės analizės metodu buvo rasti ryšiai tarp... [toliau žr. visą tekstą] / Modern business is increasingly looking for more effective marketing techniques, not only in domestic but also international markets. Over the past few years, online auctions became very popular, which encouraged the business move to Internet. Online auctions based on content management principles and rules could help to increase business efficiency. The operating principles of online auctions are reviewed and analyzed in this graduation paper. Online auction systems diversity is analyzed in analytical part of the work. Four different auction systems were analyzed and their main development principles (rules) were summarized. Considering to analysis part online auction model that can help companies increase sales and profits through the auction approach was designed. Experimental study has been made to verify the functionality of the proposed model. Data – jewelry – listings were collected from the world's largest online auction eBay. Quantitative and qualitative data was analyzed; the results are shown in graphs and tables. The final result was derived under the rules of price categories to choose the basic parameters of an auction: the starting price, auction duration and reliability. New benefit option was introduced, which enabled to compare and evaluate the obtained rules. Different methods were used to generate and evaluate auction rules. One of them is self organizing map (SOM). Its aid was used to classify the data. The statistical analysis method was used to evaluate... [to full text]
324

Importance Sampling to Accelerate the Convergence of Quasi-Monte Carlo

Hörmann, Wolfgang, Leydold, Josef January 2007 (has links) (PDF)
Importance sampling is a well known variance reduction technique for Monte Carlo simulation. For quasi-Monte Carlo integration with low discrepancy sequences it was neglected in the literature although it is easy to see that it can reduce the variation of the integrand for many important integration problems. For lattice rules importance sampling is of highest importance as it can be used to obtain a smooth periodic integrand. Thus the convergence of the integration procedure is accelerated. This can clearly speed up QMC algorithms for integration problems up to dimensions 10 to 12. (author's abstract) / Series: Research Report Series / Department of Statistics and Mathematics
325

Educators and learners' perceptions and experiences regarding the effectiveness of school rules in the Fezile Dabi District / Monica Dirks (née Forbes)

Dirks, Monica January 2012 (has links)
The objective of this research was to investigate the perceptions and experiences of educators and Grade 6 and 7 learners on the effectiveness of school rules at public primary schools within the Fezile Dabi school district. Chapter Two of this dissertation focused on the specific identification of what effective school rules comprise of, as perceived by the academic community. In order to provide the reader with an overview of the nature of effective school rules, this chapter was divided into providing a short historical reflection on discipline, looking at the nature of discipline, developing a South African framework for legal school rules and taking note of international and foreign law relevant to the topic of this dissertation. The researcher then discussed the outlines of the research design used to collect, edit and analyse the data in Chapter Three. The chapter included the research paradigm, and the difference between research designs was highlighted to motivate the choice for the research design. The research design chosen for this study was a quantitative design. The researcher also indicated that she used a pilot study while conducting the empirical research of this dissertation. It was followed by the data collection method and the data collection strategies were discussed. Reliability and validity were dealt with and the guarantees thereof included. The chapter negotiated ethical considerations and ended with a discussion of foreseen research challenges. The data were extrapolated from questionnaires. This study was conducted at 6 primary schools in the smaller Metsimaholo district. Learner participants (n = 421), as well as educator participants (n = 54), were selected to answer the same/similar questions on the effectiveness and experiences concerning school rules so as to enable comparisons of learners and educators’ perceptions of learner misconduct. The data were analysed and interpreted. Learner responses were used to determine the factor analysis, after which the same factors were applied for educators. The empirical study led to the following findings: • According to this study, it appears that educators with more experience than the average educator do not necessarily have command of content on the contemporary approach to dealing with learner discipline, which may contribute to learner misconduct. • According to the responses of participants, it seems that the role players are not aware of their influence on one another in terms of learner misconduct. *Educators are not aware of the influence of gang activities on learners. *Educators are not aware of the high prevalence of abuse within their school communities. *Learners are not aware of the educators’ concerns for the influence of family structures and divorces. *Educators feel that they are not respected by parents. • Learners acknowledge that they have less control over and input into the drawing up of school rules, than educators are willing to admit. • Some learners indicate that educators turn to illegal forms of punishment in a desperate attempt to maintain discipline. / MEd, North-West University, Vaal Triangle Campus, 2012
326

MapReduce network enabled algorithms for classification based on association rules

Hammoud, Suhel January 2011 (has links)
There is growing evidence that integrating classification and association rule mining can produce more efficient and accurate classifiers than traditional techniques. This thesis introduces a new MapReduce based association rule miner for extracting strong rules from large datasets. This miner is used later to develop a new large scale classifier. Also new MapReduce simulator was developed to evaluate the scalability of proposed algorithms on MapReduce clusters. The developed associative rule miner inherits the MapReduce scalability to huge datasets and to thousands of processing nodes. For finding frequent itemsets, it uses hybrid approach between miners that uses counting methods on horizontal datasets, and miners that use set intersections on datasets of vertical formats. The new miner generates same rules that usually generated using apriori-like algorithms because it uses the same confidence and support thresholds definitions. In the last few years, a number of associative classification algorithms have been proposed, i.e. CPAR, CMAR, MCAR, MMAC and others. This thesis also introduces a new MapReduce classifier that based MapReduce associative rule mining. This algorithm employs different approaches in rule discovery, rule ranking, rule pruning, rule prediction and rule evaluation methods. The new classifier works on multi-class datasets and is able to produce multi-label predications with probabilities for each predicted label. To evaluate the classifier 20 different datasets from the UCI data collection were used. Results show that the proposed approach is an accurate and effective classification technique, highly competitive and scalable if compared with other traditional and associative classification approaches. Also a MapReduce simulator was developed to measure the scalability of MapReduce based applications easily and quickly, and to captures the behaviour of algorithms on cluster environments. This also allows optimizing the configurations of MapReduce clusters to get better execution times and hardware utilization.
327

Law and order in Schools? : A comparative study on legal regulations of the social interaction between teacher and students in Finland and Sweden.

Yilmaz Ruhmén, Susanna January 2016 (has links)
The following thesis investigates differences and similarities in the social aspect of teachers’ professional work, as described through teachers’ rights and responsibilities regulated in national school law of the social interaction teacher-student in Finland and Sweden. This thesis is written as a pilot-study in the Swedish Research Council project concerning teacher autonomy in Sweden, England, Finland and Germany. Teacher autonomy is seen as a multidimensional concept in recent research made, and in an analytical matrix developed by Wermke and Salokangas (2016) teacher autonomy can be analyzed on different levels and in different domains of teachers’ professional work. This thesis connects to the social domain in the analytical matrix, which concerns disciplinary policies in the social interaction between teacher and students and thus explores the social part (or dimension) of teacher autonomy. The methods adopted in this thesis are content analysis and comparative method where documents on a national level (i.e. school law) and local level (i.e. rules of conduct) from Finland and Sweden are analyzed. Three terms (i.e. rights, responsibility and offensive actions) guide the analysis together with three analytical questions drawing on Ingersoll’s (2003) research where decisions concerning the social aspect of schooling was proven to be the most important area of teachers’ decision-making power. The results of the investigation indicate that there are both similarities and differences in how the social aspect of teachers’ work is described on national and local level in Finland and Sweden. On national level for example, both Finnish and Swedish teachers can take disciplinary measures to maintain a safe study- and classroom environment, although it is more regulated in the Finnish school law. The investigation also shows that there is a clearer connection between the national level and the local level in Finland, a connection which cannot be perceived in the Swedish case. Lastly, the possibility of reporting teachers divides the two countries apart where in Sweden this is described in the school law, which is not expressed in the Finnish school law.
328

Fiscal Rules and Twin Deficits: The Link between Fiscal and External Balances

Badinger, Harald, Fichet de Clairfontaine, Aurélien, Reuter, Wolf Heinrich 07 1900 (has links) (PDF)
This paper investigates the relationship between countries' fiscal balances and current accounts with an emphasis on the role of fiscal rules. The direct effect of fiscal policy on the current account via aggregate (import) demand is potentially amplified by indirect effects, materializing through interest rate effects and inter-generational transfers that reduce savings. On the other hand, the implied positive relation between fiscal and external balances is potentially attenuated by offsetting changes in savings through Ricardian equivalence considerations. We expect this attenuation effect to be stronger in countries with more stringent fiscal rules and test this hypothesis using a panel of 73 countries over the period 1985-2012. As previous studies we find a positive effect of fiscal balances on the current account, supporting the twin deficit hypothesis. However, the effect of fiscal balances on the current account depends on the stringency of fiscal (budget balance or debt) rules in place; it is reduced by one third on average and virtually eliminated for countries with the most stringent fiscal rules. (authors' abstract) / Series: Department of Economics Working Paper Series
329

The Brier Rule Is not a Good Measure of Epistemic Utility (and Other Useful Facts about Epistemic Betterness)

Fallis, Don, Lewis, Peter J. 14 December 2015 (has links)
Measures of epistemic utility are used by formal epistemologists to make determinations of epistemic betterness among cognitive states. The Brier rule is the most popular choice (by far) among formal epistemologists for such a measure. In this paper, however, we show that the Brier rule is sometimes seriously wrong about whether one cognitive state is epistemically better than another. In particular, there are cases where an agent gets evidence that definitively eliminates a false hypothesis (and the probabilities assigned to the other hypotheses stay in the same ratios), but where the Brier rule says that things have become epistemically worse. Along the way to this 'elimination experiment' counter-example to the Brier rule as a measure of epistemic utility, we identify several useful monotonicity principles for epistemic betterness. We also reply to several potential objections to this counter-example.
330

Visualizing association rules in hierarchical groups

Hahsler, Michael, Karpienko, Radoslaw 07 May 2016 (has links) (PDF)
Association rule mining is one of the most popular data mining methods. However, mining association rules often results in a very large number of found rules, leaving the analyst with the task to go through all the rules and discover interesting ones. Sifting manually through large sets of rules is time consuming and strenuous. Although visualization has a long history of making large amounts of data better accessible using techniques like selecting and zooming, most association rule visualization techniques are still falling short when it comes to large numbers of rules. In this paper we introduce a new interactive visualization method, the grouped matrix representation, which allows to intuitively explore and interpret highly complex scenarios. We demonstrate how the method can be used to analyze large sets of association rules using the R software for statistical computing, and provide examples from the implementation in the R-package arulesViz. (authors' abstract)

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