Thesis (Ph.D.)--University of Missouri-Columbia, 2007. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on March 23, 2009) Vita. Includes bibliographical references.

Controlling resource usage is important for the reliability, efficiency and security of software systems. Automated analyses for bounding resource usage can be invaluable tools for ensuring these properties. Hofmann and Jost have developed an automated static analysis for finding linear heap space bounds in terms of the input size for programs in a simple functional programming language. Memory requirements are amortized by representing them as a requirement for an abstract quantity, potential, which is supplied by assigning potential to data structures in proportion to their size. This assignment is represented by annotations on their types. The type system then ensures that all potential requirements can be met from the original input’s potential if a set of linear constraints can be solved. Linear programming can optimise this amount of potential subject to the constraints, yielding a upper bound on the memory requirements. However, obtaining bounds on the heap space requirements does not detect a faulty or malicious program which uses excessive stack space. In this thesis, we investigate extending Hofmann and Jost’s techniques to infer bounds on stack space usage, first by examining two approaches: using the Hofmann- Jost analysis unchanged by applying a CPS transformation to the program being analysed, then showing that this predicts the stack space requirements of the original program; and directly adapting the analysis itself, which we will show is more practical. We then consider how to deal with the different allocation patterns stack space usage presents. In particular, the temporary nature of stack allocation leads us to a system where we calculate the total potential after evaluating an expression in terms of assignments of potential to the variables appearing in the expression as well as the result. We also show that this analysis subsumes our previous systems, and improves upon them. We further increase the precision of the bounds inferred by noting the importance of expressing stack memory bounds in terms of the depth of data structures and by taking the maximum of the usage bounds of subexpressions. We develop an analysis which uses richer definitions of the potential calculation to allow depth and maxima to be used, albeit with a more subtle inference process.

While relational databases are still the preferred approach for storing data, XML is emerging as the primary standard for representing and exchanging data. Consequently, it has been increasingly important to provide a uniform XML interface to various data sources— integration; and critical to protect sensitive and confidential information in XML data — access control. Moreover, it is preferable to first detect and repair the inconsistencies in the data to avoid the propagation of errors to other data processing steps. In response to these challenges, this thesis presents an integrated framework for cleaning, integrating and securing data. The framework contains three parts. First, the data cleaning sub-framework makes use of a new class of constraints specially designed for improving data quality, referred to as conditional functional dependencies (CFDs), to detect and remove inconsistencies in relational data. Both batch and incremental techniques are developed for detecting CFD violations by SQL efficiently and repairing them based on a cost model. The cleaned relational data, together with other non-XML data, is then converted to XML format by using widely deployed XML publishing facilities. Second, the data integration sub-framework uses a novel formalism, XML integration grammars (XIGs), to integrate multi-source XML data which is either native or published from traditional databases. XIGs automatically support conformance to a target DTD, and allow one to build a large, complex integration via composition of component XIGs. To efficiently materialize the integrated data, algorithms are developed for merging XML queries in XIGs and for scheduling them. Third, to protect sensitive information in the integrated XML data, the data security sub-framework allows users to access the data only through authorized views. User queries posed on these views need to be rewritten into equivalent queries on the underlying document to avoid the prohibitive cost of materializing and maintaining large number of views. Two algorithms are proposed to support virtual XML views: a rewriting algorithm that characterizes the rewritten queries as a new form of automata and an evaluation algorithm to execute the automata-represented queries. They allow the security sub-framework to answer queries on views in linear time. Using both relational and XML technologies, this framework provides a uniform approach to clean, integrate and secure data. The algorithms and techniques in the framework have been implemented and the experimental study verifies their effectiveness and efficiency.

This thesis examines user interaction with instrumentation in the specific context of space science. It gathers together existing practice in machine interfaces with a look at potential future usage and recommends a new approach to space science projects with the intention of maximising their science return. It first takes a historical perspective on user interfaces and ways of defining and measuring the science return of a space instrument. Choices of research methodology are considered. Implementation details such as the concepts of usability, mental models, affordance and presentation of information are described, and examples of existing interfaces in space science are given. A set of parameters for use in analysing and synthesizing a user interface is derived by using a set of case studies of diverse failures and from previous work. A general space science user analysis is made by looking at typical practice, and an interview plus persona technique is used to group users with interface designs. An examination is made of designs in the field of astronomical instrumentation interfaces, showing the evolution of current concepts and including ideas capable of sustaining progress in the future. The parameters developed earlier are then tested against several established interfaces in the space science context to give a degree of confidence in their use. The concept of a simulator that is used to guide the development of an instrument over the whole lifecycle is described, and the idea is proposed that better instrumentation would result from more efficient use of the resources available. The previous ideas in this thesis are then brought together to describe a proposed new approach to a typical development programme, with an emphasis on user interaction. The conclusion shows that there is significant room for improvement in the science return from space instrumentation by attention to the user interface.

The first purpose of the study described in this thesis was to provide validation information of three questionnaires that were modified and translated into the Thai language, namely, the Questionnaire on Teacher Interaction (QTI), the Science Laboratory Environment Inventory (SLEI), and the Attitude to Biology Class (ABC). A second purpose was to determine students' perceptions of teacher-student interactions and laboratory learning environments and their attitudes to biology classes in secondary schools in Thailand. A sample of 1,194 students from 37 biology classes in 37 schools completed the three questionnaires. The results of the study showed that most students in secondary schools of Thailand have moderately positive attitudes to their biology class. Students perceived their teachers as having good leadership, being helping/friendly, and understanding, but seldom uncertain, dissatisfied or admonishing. They also perceived that sometimes their teachers were strict, however allowing students responsibility and freedom. In biology laboratories, they perceived the environments as employing good student cohesiveness, less open-endedness and integration of the theory and practical, the rules were not clear and the materials were not good and insufficient. There were differences between students' actual and ideal perceptions of classroom interactions and laboratory learning environments. Students preferred teachers who showed strong leadership, were more helping and understanding, who gave their students more responsibility and freedom, and who were less uncertain, dissatisfied, admonishing and strict. / Also, students preferred a biology laboratory environment with higher levels on the scales of Open-Endedness, Integration, Rule Clarity, and Material Environment but not Student Cohesiveness. Some commonality between the QTI and the SLEI scales was found in their contributions to the variance in student attitudes to biology classes. So now the QTI and the SLEI can be used by biology teachers and other science teachers in secondary schools who wish to improve science teaching and learning in Thailand.

The purpose of this study was to assess the measures of the Science Laboratory Environment Inventory (SLEI), an existing classroom environment measurement instrument, to provide up-to-date norms and validation evidence for a U.S. secondary school population. This instrument’s measures were established as a means of examining students’ perceptions of their learning environment in science classrooms, and subsequently providing indicators of performance. Pedagogical changes have taken place in the science classroom fostered by the National Science Standards. This study included an examination of the SLEI measures using Mesick’s validity framework including an in-depth analysis of the instrument’s content, substance, structure, generalizability and external validity. Rasch measurement theory was employed to investigate specific components of the instrument including item fit, rating scale function, dimensionality and individual performance information. Three hundred and fifty five high school science students completed the SLEI. Structural equation modeling was used to assess the dimensional structure of the measures of the instrument. Analyses revealed that a multi-dimensional model encompassing five distinct factors and excluding negatively worded items best characterized the SLEI measures. Multidimensional measures created by scaling the data to the Multidimensional Random Coefficients Multinomial Logit (Rasch) Model exhibited suitable rating scale structure, item quality, and reliability of separation. Analyses by academic grouping revealed that students in high achieving courses had a more favorable perception of all aspects of their learning environments when compared to students in the regular courses. In addition, student perceptions of the lab were influenced by the extent of students’ experience learning science. To determine whether differences observed by grade level could be attributable to biology learning experience versus experience in school, additional analyses were completed. The analysis revealed that differences in perception were consistent across academic achievement groups as well as experience level by first year and beyond (course level) rather than by grade level. This validation study has provided additional and up-to-date evidence concerning the validity of SLEI measures. Coupled with the existing research revealing positive correlations between student perceptions of their learning environments and their academic achievement, the outcomes reported here provide a foundation for future assessment of the relationship between classroom environment and student achievement. / Ph. D.

La recherche de molécules organiques à la surface de Mars est l’un des enjeux majeurs pour caractériser son habitabilité passée et/ou présente. C’est l’un des objectifs de la mission spatiale Mars Science Laboratory (MSL) et en particulier de l’instrument Sample Analysis at Mars (SAM) à bord du robot Curiosity. Cette thèse s’inscrit dans l’aide au traitement et l’interprétation des données de SAM, en vue de détecter et d’effectuer l’inventaire des molécules organiques à la surface de Mars. Ces travaux portent en premier lieu sur les performances analytiques du chromatographe en phase gazeuse (CPG) de SAM et sur l’identification des molécules organiques dans les échantillons solides martiens analysés. A cette fin, j’ai étudié les performances de la chaine d’injection et de séparation du CPG de SAM dans les conditions opératoires de vol reproduites en laboratoire. J’ai également créé une base de données des temps de rétention de molécules présentes, et potentiellement présentes sur Mars, qui sert de référence pour le traitement des données de vol. Ces données ont permis d’identifier des molécules organiques dans les échantillons solides martiens et d’expliquer pourquoi certaines d’entre elles, supposées présentes, ne sont pas détectées. La deuxième partie de l’étude est focalisée sur l’impact des minéraux oxychlorés sur les molécules organiques, lors de la pyrolyse. Pour ce faire, j’ai développé une approche systématique d’étude de la pyrolyse de molécules organiques en présence de minéraux oxydants, ayant tous deux une forte probabilité de se trouver à la surface de Mars. J’ai ainsi pu étudier l’évolution et/ou destruction des molécules organiques, déterminer celles pouvant être à l’origine des composés chlorés détectés sur Mars, évaluer l’impact de la concentration en minéraux oxychlorés et celui du paramètre de température de pyrolyse. Les résultats indiquent que le nombre, la nature, et les abondances relatives des composés formés au cours de la pyrolyse, dépendent de la nature des phases minérales et organiques, de la concentration en minéraux oxychlorés et de la température de pyrolyse. / The search for organic molecules at the Mars’ surface is of primary interest to understand its past and/or present habitability. It is one among the main goals of the Mars Science Laboratory (MSL) space mission and especially of the Sample Analysis at Mars (SAM) experiment onboard the Curiosity rover. This thesis deals with the support to the SAM data treatment and interpretation, which aims to detect and inventory the organic molecules at the Mars’ surface. The first part of this work focuses on the analytical capabilities of the SAM gas chromatograph (GC) and the identification of the organics in the solid samples analysed on Mars with the flight model. To do so, I studied the analytical chain from injection to separation of the SAM GC in the flight operating conditions reproduced in the laboratory. I also created a library of retention times for molecules present or potentially present on Mars, and used as a reference library to treat the flight data. These data allowed to identify the organics in the martian solid samples, and to explain why a few molecules, expected to be present, are not detected. The second part of the thesis focuses on the impact of oxychlorine phases on the organics, during the pyrolysis process. With this aim, I developed a systematic approach to study the pyrolysis of organic molecules on the presence of oxidant minerals that have a high probability of presence at the Mars surface.The evolution and/or destruction of the organics was evaluated. We also looked for the organic and inorganic compounds that can be the precursors of the chlorohydrocarbons detected on Mars with SAM. Finally, we evaluated the influence of the oxychlorines concentration and of the pyrolysis temperature parameter. The results show that the number, the nature and the relative abundances of the compounds formed during the pyrolysis, depend on the nature of the organic and inorganic phases, of the concentration of the oxychlorines phases and of the pyrolysis temperature.

The major purpose of this study was to evaluate the impact of a science course for prospective elementary teachers on their perceptions of the learning environment, attitudes towards science, and understandings of the nature of science. The sample consisted of 525 female students enrolled in 27 classes of A Process Approach to Science (SCED 401) at a large urban university in Southern California. Also comparisons were made between SCED 401 and the students' previous laboratory course with regard to the learning environment and attitudes. Perceptions of the learning environment were measured using scales from the Science Laboratory Environment Inventory (Open-Endedness and Material Environment) and the What Is Happening In this Class? (Student Cohesiveness, Instructor Support, Cooperation, Investigation). Attitudes towards science were assessed using the Enjoyment of Science Lessons scale from the Test of Science-Related Attitudes (TOSRA). Students completed the Nature of Scientific Knowledge Survey (NSKS) based on their entire science education experience-not just the one laboratory class which they had taken previously. Comparisons were then made with their understandings after having completed SCED 401. Finally, associations between the learning environment and the student outcomes of attitudes and understandings of the nature of science were explored. This study embraced the current trend in classroom learning environments research of combining quantitative and qualitative methods. Qualitative components included items from the open-ended questionnaire, Views of Nature of Science, interviews with students, and an analysis of concept maps. The qualitative findings expanded and complemented the quantitative results and, in several cases, supported the construct validity of scales assessing the learning environment and attitudes. / Another purpose of this study was to investigate the effects of using real research data for growth rates of four species of Antarctic seabirds (i.e., implementing an 'intervention') in six classes of SCED 401. The objective of the intervention was to increase the authenticity and quality of an experimental design project. In addition, the wildlife biologist who collected the data guided the students during the project. Although the intervention did not lead to an appreciable improvement in students' perceptions of the learning environment, differences between intervention and nonintervention classes were statistically significant for Enjoyment of Science Lessons from the TOSRA and for Creative from the NSKS (effect sues were 2.64 and 2.06 standard deviations, respectively). Results of this study indicated that during a factor analysis, the large majority of learning environment items belonged to their a priori scale (43 out of 46 items had factor loadings above 0.40) A valid instrument for use with prospective elementary teachers was produced by combining relevant scales from the Science . Laboratory Environment Inventory and the What Is Happening In this Class? A weaker factor structure was found for the Nature of Scientific Knowledge Survey. However, by moving close to half of the -faulty' items from the NSKS, the internal consistency reliability of scales improved considerably. This study also found large and statistically significant differences between students' previous laboratory class and SCED 401 for all six leaning environment scales. The largest difference was found for the level of Open-Endedness (effect size was 6.74 standard deviations). / A statistically significant difference also was found for Enjoyment of Science Lessons (effect size was 2.98 standard deviations). Differences were not as dramatic with regard to understandings of the nature of science, although differences for two scales (Creative and Unified) from the NSKS were positive and statistically significant. This study replicated past research by finding statistically significant positive correlations between all six learning environment scales and Enjoyment of Science Lessons. However, by far, Instructor Support had the largest independent association with enjoyment, using both the individual and class mean as the units of analysis. A positive link between a favorable leaning environment and the student outcome of understanding nature of science also was found. This research makes a distinctive contribution to the learning environments field because it is the first study to investigate laboratory classroom environments at the university level with prospective elementary teachers. The study is also the first to build a bridge between the classroom learning environment and the student outcome of understanding the nature of science. The study has implications for undergraduate laboratory course instructors, for science teacher educators who develop and instruct in elementary teacher preparation programs, and for future elementary teachers and the science learning of their future students.

The purposes of this study were to explore understanding of preservice science teachers&rsquo / (PSTs) nature of science (NOS) views during the explicit-reflective and inquiry-based laboratory instruction and investigate PSTs&rsquo / perspectives and experiences related to learning NOS aspects in the science laboratory course. This study was carried out during the Laboratory Application in Science II course. A total of 45 PSTs participated to the study. The design of the study was qualitative and exploratory in nature. In the initial phase of the study, the researcher collected qualitative data with open-ended questionnaire to explore PSTs&rsquo / NOS views. Then, during the semester, reflection papers were collected to understand PSTs&rsquo / experiences with the intervention and to detect development about each NOS aspect. At the end of the semester, qualitative questionnaire and semi-structured interviews were conducted to determine the impact of the explicit-reflective and inquiry-based laboratory instruction. The results showed that all of the PSTs were able to make appropriate connections among the laboratory activities and the targeted NOS aspects at the end of the instruction. In addition, many PSTs developed their understanding levels of each aspect of nature of science. Moreover, findings revealed that some of the PSTs made connections among NOS aspects. Three main factors / discussions and presentations, using inquiry skills, and doing inquiry-based laboratory activities were determined as provide to PSTs to develop their NOS understanding. Furthermore, at the end PSTs developed their perspectives about teaching NOS.

Hot wire anemometers have been used in several wind velocity sensors deployed in Mars. They are based in keeping the temperature of a surface at a constant value, above the ambient. This is done by means of a heater controlled with an electronic system. The cooling rate of each point at the sensor surface can be used to calculate the wind velocity and direction. However, due to turbulent fluctuations, the cooling rate is not constant even in the case of constant velocity. Moreover, RANS simulations cannot estimate such fluctuations as they only provide an estimation of the averaged flow field. The goal of this work has been to estimate such fluctuations and the e↵ect they might have on the sensor readings. To do so, the turbulent cooling rate (Nusselt number) of a sensor with a generic shape, under the typical conditions to be find in Mars, has been simulated using high performance LES (Large Eddy Simulation) simulations and compared with RANS and URANS simulations.