This study is an empirical analysis of the 2009 and 2010 forms of the Gyeonggi English Communicative Ability Test (GECAT) based on the responses of 2,307 students to the 2009 GECAT and 2,907 students to the 2010 GECAT. The GECAT is an English proficiency examination sponsored by the Gyeonggi Provincial Office of Education (GOE) in South Korea. This multiple-choice test has been administered annually at the end of each school year to high school students since 2004 as a measure of the students' ability to communicate in English. From 2004 until 2009, the test included 80 multiple-choice items, but in 2010, the length of the test was decreased to include only 50 items. The purpose of this study was to compare the psychometric properties of the 80-item 2009 form of the test with the psychometric properties of the shorter 50-item test using both Classical Test Theory item analysis statistics and parameter estimates obtained from 3-PL Item Response Theory. Cronbach's alpha coefficient for both forms was estimated to be .92 indicating that the overall reliability of the scores obtained from the two different test forms was essentially equivalent. For most of the six linguistic subdomains, the average classical item difficulty indexes were very similar across the two forms. The average of the classical item discrimination indexes were also quite similar for the 2009 80-item test and the 50-item 2010 test. However, 13 of the 2009 items and 3 of the 2010 had point biserial correlations with either negative or lower than acceptable positive values. A distracter analysis was conducted for each of these items with less than acceptable discriminating power as a basis to revise them. Total information functions of 6 subdomain tests (speaking, listening, reading, writing, vocabulary and grammar) showed that most of the test information functions of the 2009 GECAT were peaked at the ability level of around 0.9 < θ < 1.5, while those of the 2010 GECAT were peaked at the ability level of around 0.0 θ < 0.6. Recommendations for improving the GECAT and conducting future research are included.

Wireless broadband technologies provide ubiquitous broadband access to wireless users, enabling services that were available only to wireline users. At the same time, with the steady growth of real-time streaming applications such as video on demand (VoD), voice over IP (VoIP), massive online gaming, and so forth, the IEEE 802.16 standard (commonly known as WiMAX) has emerged as one of the strongest contenders to provide such kind of broadband wireless access services. WiMAX has specified some advanced lard features at physical (PHY) layer techniques and media access control (MAC) layer protocols, which adopted many Quality of Service (QoS) scheduling algorithms, resource allocation, Hybrid ARQ and so on. Moreover, forward error correction (FEC) and automatic repeat request (ARQ) techniques have already specified in the standard and they are used to support real-time streaming services in all kind of channel conditions. Inside this thesis, we propose an efficient fast feedback algorithm and buffer congestion control improvement scheme for data streaming over WiMAX networks. Two reserved bits in Generic MAC header (GMH) of each MPDU in WiMAX systems are utilized. The first reserved bit is used as a trigger in fast feedback strategy to add more robust coding and choose better feedback channel when the feedback message does not arrive properly within its cycle time trip (CTT) or after timeout. The second reserved bit is used to inform the base station about the serving subscriber stations¡¦ buffers states when their buffers are above the predefine-threshold value. Increasing number of retrieval of the feedback message, which means we can increase restore-bit-error probabilities within each frame, and then the throughput performance shall increase as well. In addition, by having each subscriber stations or service station¡¦s buffer states knowledge, the BS will be able to provide extra bandwidth allocation to the SSs more efficiency and accuracy. Keywords: WiMAX, PHY, MAC, Hybrid ARQ, QoS, Generic MAC header, CTT, Fast Feedback, Buffer Congestion Control Improvement, Real-Time streaming.

Background: The presence of muscular deficiency seems to be a major cause of back pain that requires counteractions. Considering that the autochthonous back muscles, responsible for straightening and stabilizing the spine, cannot be activated voluntarily, they can be strengthened only through specific training. The computer-supported test and training system (CTT) Centaur (BfMC GmbH, Leipzig, SN, Germany) seems well suited for this purpose. To show its potential as a reliable diagnostic and training tool, this study aimed to evaluate the test-retest reliability of this 3D spatial rotation device. Methods: A prospective pilot study was conducted in 20 healthy volunteers of both sexes. For test-retest reliability analysis, three measurements were performed with a two-day interval between each measurement. Each measurement consisted of a one-minute endurance test performed in eight different positions (transverse plane). During the test, the subject was tilted by 90° in the sagittal plane from a neutral, upright position. Meanwhile, the subject's level of upper body stabilization along the body axis was assessed. All trunk movements (momentum values) were quantified by a multicomponent force sensor and standardized relative to the subject's upper body mass. The range of motion was assessed by 95% confidence ellipse analysis. Here, all position-specific confidence ellipses for each measurement were merged to a summarized quantity. Finally, ICC analysis using a single-rating, absolute agreement, two-way mixed-effects model and a Bland-Altman plot was performed to determine the reliability. Results: Considering all measurements (t1, t2, t3), the ICC for reliability evaluation was 0.805, and the corresponding 95% confidence interval (CI) was [0.643, 0.910]. Moreover, the Bland-Altman plots for all three pairs of time points did not show significant differences. Conclusion: This study concludes that the CTT Centaur shows good test-retest reliability, indicating it can be used in clinical practice in the future.

The main topic of this work is the analysis of the measurement of partial discharge measurements on high voltage cables. The thesis also deals with other measurements, including the measurement of the loss factor and the voltage retention and breakdown test. Part of the text describes the issue of partial discharge, its measurement by galvanic method and methods of elimination of disturbing influences that affect this method in terms of sensitivity and accuracy of the measured values. Thesis also describes the construction of the cables, their marking and the tests carried out on them. There is also a description of the cable terminals used for measuring, especially water terminals, which are designed for high voltages and which are carried out in the practical part of the thesis. The next part deals with problems prior to the commissioning of water terminals and their preparation for certain tests, including description and evaluation of the results of the measurements.

This study empirically compares the Classical Test Theory (CTT) and the Partial Credit Model (PCM) of Rasch focusing on the invariance of item parameters. The invariance concept which is the consequence of the principle of specific objectivity was tested in both CTT and PCM using the results of learners who wrote the National Senior Certificate (NSC) Mathematics examinations in 2010. The difficulty levels of the test items were estimated from the independent samples of learn- ers. The same sample of learners used in the calibration of the difficulty levels of the test items in the PCM model were also used in the calibration of the difficulty levels of the test items in CTT model. The estimates of the difficulty levels of the test items were done using RUMM2030 in the case of PCM while SAS was used in the case of CTT. RUMM2030 and SAS are both the statistical softwares. The analysis of variance (ANOVA) was used to compare the four different design groups of test takers. In cases where the ANOVA showed a significant difference between the means of the design groups, the Tukeys groupings was used to establish where the difference came from. The research findings were that the test items' difficulty parameter estimates based on the CTT theoretical framework were not invariant across the different independent sample groups. The over- all findings from this study were that the CTT theoretical framework was unable to produce item difficulty invariant parameter estimates. The PCM estimates were very stable in the sense that for most of the items, there was no significant difference between the means of at least three design groups and the one that deviated from the rest did not deviate that much. The item parameters of the group that was representative of the population (proportional allocation) and the one where the same number of learners (50 learners) was taken from different performance categories did not differ significantly for all the items except for item 6.6 in examination question paper 2. It is apparent that for the test item parameters to be invariant of the group of test takers in PCM, the group of test takers must be heterogeneous and each performance category needed to be big enough for the proper calibration of item parameters. The higher values of the estimated item parameters in CTT were consistently found in the sample that was dominated by the high proficient learners in Mathematics ("bad") and the lowest values were consistently calculated in the design group that was dominated by the less proficient learners. This phenomenon was not apparent in the Rasch model. / Mathematical Sciences / M.Sc. (Statistics)

Never before in history has the amount of international trade been higher or more efficient than it is today. The fastest growing type of trade is the speculative currency trading, searching for instant profit based only on the anticipation of the variations in currency exchange rates. When currency speculation becomes an influential part of the capital flows it becomes harmful and creates instability of currency systems. Exchange rates starts to fluctuate due to the will and anticipation of speculators rather than the economic health of the country associated with the currency. This has led to recurring currency crises all over the world and an increased interest in regulatory mechanisms. One of the most discussed mechanisms proposed to handle this harmful evolution of the foreign exchange markets is the Currency Transaction Tax (CTT). The CTT stipulates a low tax (0.1 per cent) on all currency transaction to curb the incitement of short-term speculation based on a large amount of smaller transactions. The purpose of this thesis is to examine whether an implementation of a CTT is compatible with the EU treaties. This purpose consists of two research questions; whether the CTT is in conformity with the substantive law of the EU, more precisely the free movements of capital, and if the CTT is in conformity with the Economic and Monetary Union (EMU) and the exclusive power of the European System of Central Banks (ESCB) over monetary policy. Since this thesis aims to identify if the CTT is in conformity with existing legislation, the traditional doctrinal method is used for identifying and analysing potential difficulties with the CTT and to interpret these provisions in the light of ECJ case law and literature. The thesis concludes that the CTT is in conformity with the EU treaties. It does however require the full cooperation of the ESCB and ECB to achieve the objectives; to create a more stable currency market. The CTT is ready to implement.

This study empirically compares the Classical Test Theory (CTT) and the Partial Credit Model (PCM) of Rasch focusing on the invariance of item parameters. The invariance concept which is the consequence of the principle of specific objectivity was tested in both CTT and PCM using the results of learners who wrote the National Senior Certificate (NSC) Mathematics examinations in 2010. The difficulty levels of the test items were estimated from the independent samples of learn- ers. The same sample of learners used in the calibration of the difficulty levels of the test items in the PCM model were also used in the calibration of the difficulty levels of the test items in CTT model. The estimates of the difficulty levels of the test items were done using RUMM2030 in the case of PCM while SAS was used in the case of CTT. RUMM2030 and SAS are both the statistical softwares. The analysis of variance (ANOVA) was used to compare the four different design groups of test takers. In cases where the ANOVA showed a significant difference between the means of the design groups, the Tukeys groupings was used to establish where the difference came from. The research findings were that the test items' difficulty parameter estimates based on the CTT theoretical framework were not invariant across the different independent sample groups. The over- all findings from this study were that the CTT theoretical framework was unable to produce item difficulty invariant parameter estimates. The PCM estimates were very stable in the sense that for most of the items, there was no significant difference between the means of at least three design groups and the one that deviated from the rest did not deviate that much. The item parameters of the group that was representative of the population (proportional allocation) and the one where the same number of learners (50 learners) was taken from different performance categories did not differ significantly for all the items except for item 6.6 in examination question paper 2. It is apparent that for the test item parameters to be invariant of the group of test takers in PCM, the group of test takers must be heterogeneous and each performance category needed to be big enough for the proper calibration of item parameters. The higher values of the estimated item parameters in CTT were consistently found in the sample that was dominated by the high proficient learners in Mathematics ("bad") and the lowest values were consistently calculated in the design group that was dominated by the less proficient learners. This phenomenon was not apparent in the Rasch model. / Mathematical Sciences / M.Sc. (Statistics)

MAIA, José Leudo. Uso da Teoria Clássica dos Testes – TCT e da Teoria de Resposta ao Item – TRI na avaliação da qualidade métrica de testes de seleção. 2009. 325f. Tese (Doutorado em Educação) – Universidade Federal do Ceará, Faculdade de Educação, Programa de Pós-Graduação em Educação Brasileira, Fortaleza-CE, 2009. / Submitted by Maria Josineide Góis (josineide@ufc.br) on 2012-07-10T11:42:58Z No. of bitstreams: 1 2009_Tese_JLMaia.pdf: 4582126 bytes, checksum: 35b2f8279baa21b052a910889b5a7001 (MD5) / Approved for entry into archive by Maria Josineide Góis(josineide@ufc.br) on 2012-07-13T11:49:37Z (GMT) No. of bitstreams: 1 2009_Tese_JLMaia.pdf: 4582126 bytes, checksum: 35b2f8279baa21b052a910889b5a7001 (MD5) / Made available in DSpace on 2012-07-13T11:49:37Z (GMT). No. of bitstreams: 1 2009_Tese_JLMaia.pdf: 4582126 bytes, checksum: 35b2f8279baa21b052a910889b5a7001 (MD5) Previous issue date: 2009 / sse trabalho doutoral tem como proposta fazer uso da Teoria Clássica dos Testes – TCT e da Teoria de Resposta ao Item – TRI como instrumentos na avaliação da qualidade métrica de testes de seleção, sob quatro aspectos de investigação: Análise da Validez do Construto; Análise Psicométrica dos Itens; Funcionamento Diferencial dos Itens – DIF; e Função de Informação. Para tanto, foram utilizados dados dos resultados das provas de Português e Matemática do concurso vestibular da Universidade Estadual do Estado do Ceará – UECE, de 2007, em que participaram 20.016 candidatos a 38 Cursos de Graduação, somente na Capital do Estado. Para o tratamento desses dados, foram utilizados os seguintes softwares: SPSS, v15; BILOG-MG, v3.0; MULTILOG FOR WINDOWS, v1.0; e o TESTFACT v4.0. A primeira providência foi verificar a dimensionaidade dessas provas. Para tanto se utilizou o Método de Kaiser-Guttman, Scree-plot, e o Método das Cargas Fatoriais e das Comunalidades da Matriz de Fatores. A constatação foi de que a prova de Português apresentava características multidimensionais, sendo, portanto, descartada, por não atender aos pressupostos básicos da Unidimensionalidade e Independência Local dos Itens. A prova de Matemática, no entanto, por apresentar comportamento unidimensional, se tornou o foco deste trabalho. A análise da Validez do Construto foi realizada por meio dos coeficientes Alpha de Cronbach e Kuder-Richardson, tendo gerado valores iguais a 0,685, além da utilização, também, do método das Cargas Fatoriais, com cargas entre 0,837 e 0,960, indicando intensa consistência interna. A análise psicométrica dos itens foi realizada por meio dos índices de dificuldade, discriminação e acerto ao acaso, para ambas as teorias, indicando ser essa uma prova de dificuldade mediana, com bom comportamento discriminativo e baixo índice de acerto ao acaso. A análise do DIF foi realizada, segundo o gênero dos candidatos, pelos métodos Delta-plot, Maentel-Haenszel, Regressão Logística e Comparação dos Betas, indicando resultados estatísticamente não significativos, no que se concluiu não apresentar, a prova, comportamento diferenciado, segundo o gênero. A análise da Função de Informação da prova permitiu se observar que esta é particularmente válida para candidatos com aptidão em torno de 0,8750 e que, a um nível de confiança de 95%, 49,3% dos candidatos atenderiam a essa indicação. Observou-se também que 90,6% dos candidatos, em ambos os processos, apresentaram o mesmo nível de aptidão, indicando uma convergência bastante razoável entre os resultados gerados pela TCT e TRI, no entanto, no estudo amostral, a TRI identificou que 9,4% dos candidatos apresentaram maior aptidão para a realização de um curso superior que os selecionados pela TCT.

FundaÃÃo de Amparo à Pesquisa do Estado do Cearà / Esse trabalho doutoral tem como proposta fazer uso da Teoria ClÃssica dos Testes â TCT e da Teoria de Resposta ao Item â TRI como instrumentos na avaliaÃÃo da qualidade mÃtrica de testes de seleÃÃo, sob quatro aspectos de investigaÃÃo: AnÃlise da Validez do Construto; AnÃlise PsicomÃtrica dos Itens; Funcionamento Diferencial dos Itens â DIF; e FunÃÃo de InformaÃÃo. Para tanto, foram utilizados dados dos resultados das provas de PortuguÃs e MatemÃtica do concurso vestibular da Universidade Estadual do Estado do Cearà â UECE, de 2007, em que participaram 20.016 candidatos a 38 Cursos de GraduaÃÃo, somente na Capital do Estado. Para o tratamento desses dados, foram utilizados os seguintes softwares: SPSS, v15; BILOG-MG, v3.0; MULTILOG FOR WINDOWS, v1.0; e o TESTFACT v4.0. A primeira providÃncia foi verificar a dimensionaidade dessas provas. Para tanto se utilizou o MÃtodo de Kaiser-Guttman, Scree-plot, e o MÃtodo das Cargas Fatoriais e das Comunalidades da Matriz de Fatores. A constataÃÃo foi de que a prova de PortuguÃs apresentava caracterÃsticas multidimensionais, sendo, portanto, descartada, por nÃo atender aos pressupostos bÃsicos da Unidimensionalidade e IndependÃncia Local dos Itens. A prova de MatemÃtica, no entanto, por apresentar comportamento unidimensional, se tornou o foco deste trabalho. A anÃlise da Validez do Construto foi realizada por meio dos coeficientes Alpha de Cronbach e Kuder-Richardson, tendo gerado valores iguais a 0,685, alÃm da utilizaÃÃo, tambÃm, do mÃtodo das Cargas Fatoriais, com cargas entre 0,837 e 0,960, indicando intensa consistÃncia interna. A anÃlise psicomÃtrica dos itens foi realizada por meio dos Ãndices de dificuldade, discriminaÃÃo e acerto ao acaso, para ambas as teorias, indicando ser essa uma prova de dificuldade mediana, com bom comportamento discriminativo e baixo Ãndice de acerto ao acaso. A anÃlise do DIF foi realizada, segundo o gÃnero dos candidatos, pelos mÃtodos Delta-plot, Maentel-Haenszel, RegressÃo LogÃstica e ComparaÃÃo dos Betas, indicando resultados estatÃsticamente nÃo significativos, no que se concluiu nÃo apresentar, a prova, comportamento diferenciado, segundo o gÃnero. A anÃlise da FunÃÃo de InformaÃÃo da prova permitiu se observar que esta à particularmente vÃlida para candidatos com aptidÃo em torno de 0,8750 e que, a um nÃvel de confianÃa de 95%, 49,3% dos candidatos atenderiam a essa indicaÃÃo. Observou-se tambÃm que 90,6% dos candidatos, em ambos os processos, apresentaram o mesmo nÃvel de aptidÃo, indicando uma convergÃncia bastante razoÃvel entre os resultados gerados pela TCT e TRI, no entanto, no estudo amostral, a TRI identificou que 9,4% dos candidatos apresentaram maior aptidÃo para a realizaÃÃo de um curso superior que os selecionados pela TCT.