published_or_final_version / Applied English Studies / Master / Master of Arts in Applied Linguistics

In this master thesis we investigated whether it is possible to use automatically generated C code from Function Block Diagram models as an input to the CPAchecker model checker in order to generate automated test cases. Function Block Diagram is a non-executable programming and modeling language. Consequently, we need to transform this language to an executable language that can be model checked. A tool that achieves this is the MITRAC tool, a proprietary development tool used in the embedded system domain, for engineering programmable logic controllers. The purpose of this research was to investigate to what extent the generated C code using MITRAC can be reused as an input to the CPAchecker tool for automated test case generation. In order to achieve this we needed to perform certain transformations steps on the existing code. In addition, necessary instrumentations were needed in order to trigger CPAtiger, an extension of CPAchecker which generates test cases, to achieve maximum condition coverage. We showed that by performing the required modifications it is feasible to reuse the generated C code as an input to CPAchecker tool. We also showed an approach for mapping the generated test cases with the actual Function Block Diagram. We performed mutation analysis in order to evaluate the quality of the generated test cases in terms of the number of injected faults they detect. Test case generation with CPAchecker could be improved in the future in terms of reducing the number of transformations and instrumentations that are currently needed. In order to achieve this we need to add to CPAchecker tool support for structures that are used in C, such as structs. Finally we can extend the type of logic coverage criteria we can use with CPAchecker by adding additional support of FQL language.

Currently, many methods are available for the analysis of drugs of abuse in urine but they all have their drawbacks. Thus, the purpose of this research was to overcome some of these drawbacks by developing multi-analyte detection systems based on sequential or spatial techniques and immunoassays. The first system was based on a spatial technique and involved a simple indirect competitive ELISA format. This produced relatively rapid multi-analyte dip-strip ELISAs for benzoylecgonine (BE), methadone (MET) and morphine (MOR). Various enzyme-labelled antibodies, substrates and filters were investigated. A multi-analyte dip-strip assay was developed based on cellulose nitrate filters, alkaline phosphatase labelled anti-mouse second antibody and nitro blue tetrazolium / 5-bromo-4-chloro-3- indoyl phosphate (NBT /BCIP) substrate. The resulting assays gave a simple 'yes/no' result when drug was present or absent from a sample at concentrations of 1.45 f,lg ml-I , 1.55 f,lg ml-I and 1.43 f,lg ml-I for BE, MET and MOR respectively. Limitations however were encountered that caused the concentrations to be above the accepted cutoff levels for these three drugs of abuse. The second system was based on a sequential technique and involved a flow-injection nnmunoassay (FIlA). Various monoclonal antibodies, fluorotracers and immobilisation methods were investigated. For morphine, a novel simple FIlA was developed which is based on competition between a mixture of a fluorescein derivative of the drug and morphine in flow over low affinity monoclonal morphine antibodies immobilised on a N-hydroxysuccinimidyl chloroformate activated agarose immunoreactor. With this system, a split peak profile (unbound and retarded fractions) was observed under isocratic conditions with the retarded peak disappearing and the unbound peak increasing in peak height/area as the concentration of morphine increased. Using a flow-rate of 0.5 ml min-I and a fluorescein derivative dilution of 1: 100, this assay had a sample throughput of 4 samples h-I and a detection limit of 14.1 f,lg ml- I . For a flow-rate of 1.6 ml min-I and a fluorescein derivative dilution of 1: 1 00,the assay had a sample throughput of 6 samples h-I and a detection limit of 10.9 J.!g mri. The origin of the phenomenon was investigated and revealed to be due to the low association rate of the drug tracer with the morphine antibody used and the near equivalence of the monoclonal antibody affinity for its respective tracer and drug. It was found that when these values are exceeded, the "split peak" phenomenon was not observed but the reagents could be used in conventional displacement flow injection fluoroimmunoassays as was demonstrated for benzoylecgonine and methadone.

A wideband digital signal acquisition instrument intended primarily for ultrasonic experimentation has been designed and built. It comprises an integrated array of modules which combine to provide: a pulser for transducer excitation, wideband amplification (>80 MHz bandwidth), high speed sampling (>160 MHz), on-board memory (4K x 16 bits capacity), control hardware and real-time coherent averaging. The integration of the modules offers significant benefits over systems consisting of a number of separate items of equipment. The major benefit is a reduction in acquisition time which is accomplished as follows. The time relationship between the sampling clock and the input signal is controlled to minimise the signal repetitions required for interleaving. This is achieved by triggering the input signal using a pulser board locked to the sample clock. In addition, signal averaging is implemented in hardware using two memory modules and an adder module. Since the time relationship between the sampling clock and the input signal is controlled it cannot be tested using a sinewave because it is not possible to produce a sinewave which is correlated with the sampling clock. Instead, a rectangular pulse, triggered by the instrument, is applied to a single-pole low pass filter to provide the test signal. The time constant and start time is ascertained and used to reproduce the single-pole response. The reproduced response is then compared to the sampled signal to produce an error plot from which the system's linearity and effective bits can be deduced. As the system was designed for fast acquisition, and hence has a short aperture time, it is highly applicable to dynamic processes. The dynamic process application chosen was the measurement of absorption and velocity on rapidly flocculating and sedimenting colloids.

The thesis considers the development of teachers' assessment practice at key stage one from 1989 to 1995 as the National Curriculum assessment of the core subjects was piloted and implemented. It takes a longitudinal case study approach in two Hampshire Infant schools with additional evidence from other schools and LEA assessment advisers and places it within historical, research and personal contexts. It identifies how teachers' assessment and recording practice changed, how far these changes were temporary or sustained and what impact these changes had upon supporting children's learning. It proposes that in order for change to be implemented and sustained teachers' perceptions as well as their practice need to change. It compares teachers' perceptions of the relative importance of statutory tests/tasks with teacher assessment over the six years. The research shows that teachers of Y2 children were making increasing use of a range of methods for teacher assessment including observation and became increasingly confident in the dependability of their judgements through whole school planning and moderation activities. It found changes in science and design school planning and moderation activities. It found changes in science and design and technology assessment practice were not sustained when external requirements changed. It considers how schools assimilated and implemented changes in their practice and found that for change originating from one context (policy makers) and implemented in a separate context (teachers in schools) there was a time lag. National Curriculum assessment was subject to significant modifications over the six years. The thesis explores the nature of these changes, finding many were crisis led and often stimulated knee-jerk responses which had unplanned knock on effects. The research found that the absence of two way professional communication between originators and implementors limited the rate of change and the development of a common perception of teacher assessment and its significance compared to statutory tests and tasks. The evidence collected throughout the six years supports the importance of teachers' perception in the process of change and its effective implementation. It proposes that for effective implementation teachers should engage in a professional dialogue with policy makers to bring about evolutionary change in which consideration is given to the purpose and evaluation/research basis of the change required as well as the practice implications.

The attitudes and learning strategies of 100 language learners who are also users of Self-Access Centers (SACs) in a theoretical context of Self-Access Language Learning (SALL). Though questionnaire survey, the present study discovered several significant correlations between learner’s attitudes towards SALL and their language learning strategies. It also established a profile of SALL center users in their attitudes and learning strategies from an comparative view based on their previous SALL experiences. The results showed that leaners who are more ready for Self-Access tend to use affective strategies. Memory strategies are practiced more often among leaners who prefer learn grammar without teachers and have more speaking activities in class, also who are relatively more self-aware of their own learning objectives. Cognitive strategies are widely used by leaners who prefer leaning grammar by themselves, also those who are more confident to solve problems by themselves. There is a stronger intention of control over content selection for leaners who had SALL experiences, especially in utilizing non-staffing SALL resources at SACs. / published_or_final_version / Education / Master / Master of Education

Software testing is the most widely practiced approach to assure the correctness of programs. Despite decades of research progress, software testing is still considered very resource-demanding and time-consuming. In the recent decade, the wide adoption of multithreaded programs and the service-based architecture has further aggravated the problem that we are facing. In this thesis, we study issues in software testing where resource constraints (such as time spent and memory space allocated) are important considerations, and we look for testing techniques that are significantly advanced in effectiveness and efficiency given limited quotas of resources, which we refer to as budget. Our main focus is on two types of systems: concurrent systems and service-based systems. The concurrent system is a class of computing system where programs are designed as collections of interacting and parallel computational processes. Unfortunately, concurrent programs are well known to be difficult to write and test: various concurrency bugs still exist in heavily-tested programs. To make it worse, detecting concurrency bugs is expensive, which is, for example, notorious for dynamic detection techniques that target high precision. This thesis proposes a dynamic sampling framework, CARISMA, to reduce the overhead dramatically while still largely preserving the bug detection capability. To achieve its goal, CARISMA intelligently allocates the limited budget on the computation resource through sampling. The core of CARISMA is a budget estimation and allocation framework whose correctness has been proven mathematically. Another source of cost comes from the nondeterministic nature of concurrent systems. A common practice to test concurrent system is through stress testing where a system is executed with a large number of test cases to achieve a high coverage of the execution space. Stress testing is inherently costly. To this end, it is critical that the bug detection for each execution is effective, which demands a powerful test oracle. This thesis proposes such a test oracle, OLIN, which reports anomalies in the concurrent executions of programs. OLIN finds concurrency bugs that are consistently missed by previous techniques and incurs low overhead. OLIN can achieve a higher effectiveness within given time and computational budgets. Service-based systems are composed of loosely coupled and unassociated units of functional units and are often highly concurrent and distributed. We have witnessed their prosperity in recent decades. Service-based systems are highly dynamic and regression testing techniques are applied to ensure their previously established functionality and correctness are not adversely affected by subsequent evolutions. However, regression testing is expensive and our thesis focuses on the prioritization of regression test cases to improve the effectiveness of testing within predefined constraints. This thesis proposes a family of prioritization metrics for regression testing of location-based services and presents a case study to evaluate their performance. In conclusion, this thesis makes the following contributions to software testing and analysis: (1) a dynamic sampling framework for concurrency bug detection, (2) a test oracle for concurrent testing, and (3) a family of test case prioritization techniques for service-based systems. These contributions significantly improve the effectiveness and efficiency of resource utilization in software testing. / published_or_final_version / Computer Science / Doctoral / Doctor of Philosophy

Two direct elicitation of utility (D.E.U.) techniques were used to estimate risk attitudes of a group of agricultural producers. The two elicitation techniques used in the study were 1) an error-in-response model using a modified Ramsey method, and 2) stochastic dominance with respect to a function (SDF). The primary objective of the study was to determine whether the two elicitation techniques yield consistent estimates of risk attitudes. A second major objective of the study was to provide additional information about the distribution of risk attitudes among agricultural producers. The study confirmed the results of other research efforts that the majority of risk attitude parameters of agricultural producers lie within the range -.0001 and .001 with income measured in dollars [King and Robison, 1980]. The study also supports previous research results which indicate that a significant portion of decision makers exhibit risk preferring behavior, at least over some ranges of incomes. The error-in-response model classified 38.1% of the respondents as risk preferring, 47.6% as risk neutral, and 14.3% as risk averse. With only one exception, the SDF technique elicited risk preferring attitudes for every respondent over some range of income values. Individual and aggregate tests for decreasing (increasing) absolute risk aversion were conducted. No respondents were found to exhibit increasing or decreasing absolute risk aversion. The statistical comparison of the two elicitation techniques was inconclusive. A paired t-test failed to reject the null hypothesis of no difference in the estimated risk attitudes. However, the correlation between the two measures was virtually zero (-.046) suggesting that the two measures of risk attitudes are not closely related. The two elicitation techniques were also compared on other grounds. Both elicitation techniques are designed to prevent certainty bias that has plagued other D.E.U. methods. The SDF technique is found to be superior in overcoming possible interviewer bias. Neither technique is superior in coping with probability bias. The SDF technique is easier to implement but the error-in- response questionnaire is easier to formulate. The error-in- response model results in a specific estimate of the respondent's risk attitude when the negative exponential utility function is used. Based on the comparisons made in the study, the SDF procedure is considered to be superior to the error-in-response model for eliciting risk attitudes. / Graduation date: 1986

Apples growing in New Zealand, Argentina, Mexico, Michigan and Washington were used to provide the compositional data and to develop the analytical procedures for the use in verification of authenticity of apple juices. High Performance Liquid Chromatography (HPLC) techniques were applied for glucose, fructose, sucrose, sorbitol, malic, citric, quinic, shikimic, fumaric, chlorogenic acid, and hydroxymethylfurfural (HMF). L-malic acid was determined by an enzymic method. Sep-Pak C18 cartridge, anion exchange resin and millipore filter were used for sample preparation of HPLC. Influence of postharvest storage on sucrose and sorbitol content was observed but it had no effect on the glucose/fructose ratios. Quinic was the next most abundant acid in all the apple varieties examined. Paired t-test showed good agreement (p<0.01) between HPLC and enzymic determination for malic acid. Significantly high variability in chlorogenic acid content limits its utility. The influence of processing procedures on the phenolic compound was observed by comparison with commercial, self-pressed and gelatin treated apple juices. All apple juices showed two characteristic UV absorption maxima at around 280nm and 320nm, the ratio of the two maxima being relatively constant. First, second derivative spectra and fluorescence excitation and emission maxima were measured. As the order of derivative increased, the spectra became more complex and the resolution was enhanced. For the stable carbon isotope ratio analysis, juice, pulp, seeds and sugars, acids, and phenolics were fractionated using ion exchange resins and polyclar AT. Mass spectrometric measurements of ¹³C/ ¹²C ratio from whole juices showed low variability as compared to other fractions. Organic acids showed more negative values than the sugars. Phenolic fraction was most enriched in ¹²C when compared to the juice by as much as 4.6 ppt. The evidence suggests that postharvest storage and processing conditions played an important role in the variability of apple juice components. There are no marked differences in del ¹³C values with regard to apple variety or geographic origins. / Graduation date: 1985

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