Benchmark calculations for the validation of the coupled neutron kinetics/thermohydraulic code complex DYN3D-ATHLET are described. Two benchmark problems concerning hypothetical accident scenarios with leaks in the steam system for a VVER-440 type reactor and the TMI-1 PWR have been solved. The first benchmark task has been defined by FZR in the frame of the international association "Atomic Energy Research" (AER), the second exercise has been organised under the auspices of the OECD. While in the first benchmark the break of the main steam collector in the sub-critical hot zero power state of the reactor was considered, the break of one of the two main steam lines at full reactor power was assumed in the OECD benchmark. Therefore, in this exercise the mixing of the coolant from the intact and the defect loops had to be considered, while in the AER benchmark the steam collector break causes a homogeneous overcooling of the primary circuit. In the AER benchmark, each participant had to use its own macroscopic cross section libraries. In the OECD benchmark, the cross sections were given in the benchmark definition. The main task of both benchmark problems was to analyse the re-criticality of the scrammed reactor due to the overcooling. For both benchmark problems, a good agreement of the DYN3D-ATHLET solution with the results of other codes was achieved. Differences in the time of re-criticality and the height of the power peak between various solutions of the AER benchmark can be explained by the use of different cross section data. Significant differences in the thermohydraulic parameters (coolant temperature, pressure) occurred only at the late stage of the transient during the emergency injection of highly borated water. In the OECD benchmark, a broader scattering of the thermohydraulic results can be observed, while a good agreement between the various 3D reactor core calculations with given thermohydraulic boundary conditions was achieved. Reasons for the differences in the thermohydraulics were assumed in the difficult modelling of the vertical once-through steam generator with steam superheating. Sensitivity analyses which considered the influence of the nodalisation and the impact of the coolant mixing model were performed for the DYN3D-ATHLET solution of the OECD benchmark. The solution of the benchmarks essentially contributed to the qualification of the code complex DYN3D-ATHLET as an advanced tool for the accident analysis for both VVER type reactors and Western PWRs.

Thesis--Technische Universität Hannover. / Includes bibliographical references.

The internationally circulated Pool Critical Assembly (PCA) Pressure Vessel Benchmark was analyzed using the PENTRAN Parallel SN code system for the geometry, material, and source specifications as described in the PCA Benchmark documentation. Improvements to the benchmark are proposed through the application of more representative flux and volume weighted homogenized cross sections for the PCA reactor core, which were obtained from a rigorous heterogeneous modeling of all fuel assembly types in the core. A new source term definition is also proposed based on calculated relative power in each core fuel assembly with a spectrum based on the Uranium-235 fission spectra. This research focused on utilizing the BUGLE-96 cross section library and accompanying reaction rates, while examining both adaptive differencing on a coarse mesh basis, as well as the sole use of Directional Theta-Weighted (DTW) SN differencing scheme in order to compare the calculated PENTRAN results to measured data. The results show good comparison with the measured data, which suggests PENTRAN is a viable and reliable code system for calculation of light water reactor neutron shielding and dosimetry calculations. Furthermore, the improvements to the benchmark methodology resulting from this work provide a 6 percent increase in accuracy of the calculation (based on the average of all calculation points), when compared with experimentally measured results at the same spatial location in the PCA pressure vessel simulator.

This thesis aims to present solutions to improve the performance of SQLite library on mobile systems. In particular, two approaches are presented to add lightweight locking mechanisms to the SQLite library and improve concurrency of the SQLite library on Android operating system. The impact on performance is discussed after each section. Many applications on the Android operating system rely on the SQLite library to store ordered data. However, due to heavy synchronization primitives used by the library, it becomes a performance bottleneck for applications which push large amount of data into the database. Related work in this area also points to SQLite database as one of the factors for limiting performance. With increasing network speeds, the storage system can become a performance bottleneck, as applications download larger amounts of data. The following work in this thesis addresses these issues by providing approaches to increase concurrency and add light-weight locking mechanisms. The factors determining the performance of Application Programming Interfaces provided by SQLite are first gathered from IO traces of common database operations. By analyzing these traces, opportunities for improvements are noticed. An alternative locking mechanism is added to the database file using byte-range locks for fine-grained locking. Its impact on performance is measured using SQLite benchmarks as well as real applications. A multi-threaded benchmark is designed to measure the performance of fine grained locking in multi-threaded applications using common database operations. Recent versions of SQLite use write ahead logs for journaling. We see that writes to this sequential log can occur concurrently, especially in flash drives. By adding a sequencing mechanism for the write ahead log, the writes can proceed simultaneously. The performance of this method is also analyzed using the synthetic benchmarks and multi-threaded benchmarks. By using these mechanisms, the library is observed to gain significant performance for concurrent writes.

The purpose of this study is to determine whether the Data Envelopment Analysis (DEA) can be applied to Chief Executive Officer (CEO) remuneration of companies listed on the Johannesburg Stock Exchange (JSE) by defining inputs in terms of remuneration factors and outputs in terms of business factors in order to establish a benchmark for CEO remuneration. An exploratory study is conducted, using cross-sectional data from a secondary source. The sample consists of 221 companies listed on the JSE that disclosed their financial and non-financial information during 2010. The DEA was performed to estimate the relative technical efficiency of CEOs to convert their remuneration into company performance indicators. Base Pay, Perquisites and Pension, Annual Bonus Plans and Long-term Incentives were used as the inputs to the DEA model and company performance and size, measured by Return on Equity (ROE) and Total Assets respectively, were used as the outputs to the model. The empirical results prove that the DEA can be successfully applied as a benchmarking model for CEO remuneration that incorporates multiple inputs and outputs and establishes benchmarks and potential improvements for overpaid, inefficient CEOs. The CEOs from 80 of the 221 companies included in the sample emerged as the benchmark CEOs and formed the efficiency frontier against which inefficient CEOs were compared in order to determine the potential improvements for these CEOs. From a research perspective, this study contributes to the advancement of CEO remuneration research by introducing an alternative model by which CEO remuneration can be analysed. Future studies can analyse CEO remuneration by using other variables or time series data in the DEA model or combine the DEA with other methods like the regression analysis to perform more comprehensive investigations. From a practical perspective, the DEA can be used to establish a benchmark for CEO remuneration. Remuneration committees can use the results of the DEA as a guide to determine acceptable remuneration levels and decrease the pay gap between CEOs and the average worker. The originality of this study lies in the fact that it is the first South African study that used the DEA instead of the regression analysis to analyse CEO remuneration of companies listed on the JSE. This study also disaggregated Total CEO Remuneration into Base Pay, Perquisites and Pension, Annual Bonus Plans and Long-term Incentives to provide more accurate benchmark information. In addition, this is the first study that established benchmark CEO remuneration levels and suggested improvements to the remuneration package structure of overpaid, under-performing CEOs of companies listed on the JSE. / Thesis (MCom (Management Accountancy))--North-West University, Potchefstroom Campus, 2013.

The research focused on the importance of and the problem of English proficiency/literacy regarding Grade 12 learners exiting the school system and seeking entry at Institutions of Higher Learning (IHLs). Grade 12 learners’ final results have been used as a benchmark for admission into tertiary education for many years. These results have come under scrutiny over the past few years. IHLs are faced with the problem to generate ways to address the access of ill-prepared learners exiting Grade 12 and then to solve the problem of low levels of throughput and high drop-out rates among first year students, therefore the multi-faceted nature of access into South African IHLs was discussed, as well as alternative routes to enter IHLs. The researcher has experienced that the dropout rates of first year BEd English major students have been rather high. The purpose of this research was to determine what the predictive power of two measures, the English matric results of the National Senior Certificate (NSC) and the English Literacy Skills Assessment (ELSA) were on the academic success of first year BEd English major students of the North-West University on the Vaal Triangle Campus. This was primarily done to improve first year BEd English major students’ English proficiency/literacy, as well as to increase their throughput rate. The major findings of this study pointed to the lack of English language proficiency/literacy of first year BEd English major students and the low throughput rate of these students. Although the ELSA proved to be the best predictor of academic success for first year BEd English major students, the Grade 12 English results also showed a statistical significant prediction capability. The results showed that there was no significant difference between ELSA 1 (which was used as pre-test) and ELSA 2 (which was used as post-test). An improvement in the ELSA 2 results was expected, as it was written as a post-test at the end of the first year BEd English major modules, indicating that the curriculum of the first year BEd English major students had little or no positive influence on the results of the ELSA 2. This resulted in the recommendation that it would be to the advantage of first year BEd English major students to change the current first year BEd English major curriculum in order to improve students’ English proficiency/literacy, as well as their throughput rate, which will result in improved academic success. / PhD, Teaching and Learning, North-West University, Vaal Triangle Campus, 2012

The purpose of this study is to determine whether the Data Envelopment Analysis (DEA) can be applied to Chief Executive Officer (CEO) remuneration of companies listed on the Johannesburg Stock Exchange (JSE) by defining inputs in terms of remuneration factors and outputs in terms of business factors in order to establish a benchmark for CEO remuneration. An exploratory study is conducted, using cross-sectional data from a secondary source. The sample consists of 221 companies listed on the JSE that disclosed their financial and non-financial information during 2010. The DEA was performed to estimate the relative technical efficiency of CEOs to convert their remuneration into company performance indicators. Base Pay, Perquisites and Pension, Annual Bonus Plans and Long-term Incentives were used as the inputs to the DEA model and company performance and size, measured by Return on Equity (ROE) and Total Assets respectively, were used as the outputs to the model. The empirical results prove that the DEA can be successfully applied as a benchmarking model for CEO remuneration that incorporates multiple inputs and outputs and establishes benchmarks and potential improvements for overpaid, inefficient CEOs. The CEOs from 80 of the 221 companies included in the sample emerged as the benchmark CEOs and formed the efficiency frontier against which inefficient CEOs were compared in order to determine the potential improvements for these CEOs. From a research perspective, this study contributes to the advancement of CEO remuneration research by introducing an alternative model by which CEO remuneration can be analysed. Future studies can analyse CEO remuneration by using other variables or time series data in the DEA model or combine the DEA with other methods like the regression analysis to perform more comprehensive investigations. From a practical perspective, the DEA can be used to establish a benchmark for CEO remuneration. Remuneration committees can use the results of the DEA as a guide to determine acceptable remuneration levels and decrease the pay gap between CEOs and the average worker. The originality of this study lies in the fact that it is the first South African study that used the DEA instead of the regression analysis to analyse CEO remuneration of companies listed on the JSE. This study also disaggregated Total CEO Remuneration into Base Pay, Perquisites and Pension, Annual Bonus Plans and Long-term Incentives to provide more accurate benchmark information. In addition, this is the first study that established benchmark CEO remuneration levels and suggested improvements to the remuneration package structure of overpaid, under-performing CEOs of companies listed on the JSE. / Thesis (MCom (Management Accountancy))--North-West University, Potchefstroom Campus, 2013.

目前我國地價制度，主要係依地價調查估計規則規定，查估公告土地現值及公告地價。價格評估主要採區段地價方式，可能造成忽略土地個別因素影響，造成評估價格明顯遠離市價。近年來我國推行地價基準地制度，期透過引進不動產估價技術規則之規範，以個別估價方式評估基準地價格，以真實反映價格與市場波動情形。然基準地評價屬一序列式之估價方式，其評估過程是否為獨立且客觀仍須進一步加以驗證。本文依循Quan-Quigley部分調整模型之理念，對高雄市地價基準地之重估價案例進行研究，透過迴歸分析分別衡量估值與當期市場價格、前期估值之關係，推估地價人員之信心水準，並進一步分析地價基準地制度是否能確實反映市場價值波動情形。研究結果顯示估價人員存在價格部分調整策略，信心水準值偏低，存在嚴重依賴前期估值之行為，隱含地價基準地評價存在估價平滑之現象。 / Previous studies defined appraisal smoothing as reduced volatility or the lag structure of appraisal-based index as compared to transaction-based index. Most of these studies examined by aggregate level and used extensive data sets to de-smooth the appraisal-based index. This paper aims to observe smoothing behavior amongst appraisers in Taiwan. It uses re-appraisal data of the land value benchmark in Kaohsiung city and modifies the partial adjustment model, developed by Quan and Quigley. Use the concept of regression analysis to measure the ratio between the current appraisal, current market value and the pre-appraisal. By establish the confidence value, we may observe the behavior of appraisers and public assessors, and distinguish if the behavior is rational or not.

O presente trabalho elenca um rol de argumentos que apresentam a agricultura brasileira como um setor dinâmico e pujante da economia brasileira, mostrando que, muito mais do que gerar alimentos, este setor é um dos eixos de crescimento e desenvolvimento econômico, podendo contribuir muito mais para o crescimento de longo prazo da economia brasileira se ativado para este propósito. No entanto, para que se tenha um horizonte de longo prazo é necessário discutir-se a competitividade desse setor, o que é feito a partir da apresentação dos resultados de uma pesquisa de levantamento e comparação de custos de produção de Milho, Soja e Trigo, realizada entre 2008 e 2012, com a mesma metodologia, nos principais países do mundo, conhecida como Agri benchmark. Os dados mostram que o Brasil exibe alto custo de produção em relação a seus concorrentes e este estudo apresenta algumas das principais razões para essa diferença de custos, quais sejam: tributação, logística, produtividade da mão-de-obra e as diferenças entre as políticas públicas. Esta dissertação busca mensurar as Vantagens Comparativas Reveladas dos principais grãos de exportação brasileiros, com o intuito de descobrir se os altos custos de produção observados chegam a retirar a competitividade da agricultura nacional, o que se verificou somente para o caso do Trigo. / This study gives many arguments which presents Brazilian Agriculture as a dynamic and strong sector of Brazilian economy, showing that, more than the ability to supply food, this sector is one of the axis for growth and economic development. It would contribute for long term economic growth if it would be activate toward this proposal. However, for long term view is necessary to discus the competitiveness of this sector, which is made by using results of a research that compares cost of production of corn, soybean and wheat between 2008 and 2012, using the same methodology, for most producers around the world, known as Agri benchmark. The date shows that Brazil is the most expensive country in terms of cost of production in comparison with his competitors and this study also shows the main reasons, which are: taxation, logistics, workforce productivity and subsidies. This thesis measures Revealed Comparative Advantages of mains Brazilian grains produced, aiming to realize if high costs reduces agriculture competitiveness, which is observed in wheat.

[pt] Neste trabalho será descrito o Índice de Pressão criado a partir da conjunção da margem de refino e dos diferenciais de preços dos petróleos físicos. Este índice tem por função revelar possíveis descolamentos entre o preço do benchmark ICE Brent e os diversos petróleos físicos negociados. Como os benchmarks sofrem influência de diversos outros fatores econômicos, e não somente dos dados correntes de oferta e demanda, de tempos em tempos, movimentos anormais ocorrem. Espera-se também, que tentativas de manipulação dos benchmarks via operações no mercado futuro tornem-se explícitas a partir da observação do Índice de Pressão. Sua definição busca demonstrar qual o papel dos diferenciais na identificação das condições correntes de equilíbrio do mercado físico com relação ao mercado financeiro. Na primeira parte do trabalho, há uma breve descrição do mercado e sua evolução histórica. Ainda no início do trabalho, agentes chave serão apresentados e seus papéis descritos. No capítulo 3, será apresentado o mercado do Mar do Norte e a mecânica de funcionamento dos seus principais benchmarks. Uma atenção especial será dada aos complexos instrumentos que conectam as dimensões físicas e financeiras do mercado. No capítulo 4 será descrita como o funcionamento do mercado se dá a partir das negociações baseadas em diferenciais ou spreads. No capítulo final, será introduzido o Índice de Pressão. O foco deste trabalho será na definição do Índice, bem como, na aplicação da teoria num estudo de caso do petróleo colombiano Castilla. Desta forma, podemos definir este trabalho como um estudo de caso qualitativo. / [en] In this work the Pressure Index, created from the conjunction of the refining margin and the price differentials of the physical oils, will be described. This index is intended to reveal possible mismatches between the ICE Brent benchmark price and the various traded physical oils. As the benchmarks are influenced by several other economic factors, not only from the current supply and demand data, from time to time, abnormal movements occur. It is also expected that attempts to manipulate the benchmarks will become explicit. The Pressure Index seeks to demonstrate the role of the differentials in the identification of the current equilibrium conditions of the physical market in relation to the financial market. On the beginning, there is a brief description of the market and its historical evolution. Key agents will be introduced and their roles described. In Chapter 3, the North Sea market and the mechanics of its main benchmarks will be presented. Attention will be paid to the complex instruments that connect the physical and financial dimensions of the market. In Chapter 4 it will be described how the operation of the market takes place from the negotiations based on differentials or spreads. In the final chapter, the Pressure Index will be introduced. The focus of this work will be on the definition of the Index as well as on the application of the theory in a case study of the Colombian petroleum Castilla. In this way, we can define this work as a qualitative case study.