Radar sounders (RS) are low frequency remote sensing instruments that profile the shallow subsurface of planetary bodies providing valuable scientific information. The prediction of the RS performance and the interpretation of the target properties from the RS data are challenging due to the complex electromagnetic interaction between many acquisition variables. RS simulations address this issue by forward modeling this complex interaction and simulating the radar response. However, existing simulators require detailed and subjective modeling of the target in order to produce realistic radargrams. For less-explored planetary bodies, such information is difficult to obtain with high accuracy. Moreover, the high computational requirements of conventional electromagnetic simulators prohibit the simulation of a large number of radargrams. Thus, it is not possible to generate and analyze a database of simulated radargrams representative of the acquisition scenario that would be very useful for both the RS design and the data analysis phase. To overcome these difficulties and to produce realistic simulated radargrams, this thesis proposes two novel approaches to the simulation and analysis of the radar response. The first contribution is a simulation approach that leverages the data available over geological analogs of the investigated target and reprocesses them to obtain the simulated radargrams. The second contribution is a systematic approach to the generation and analysis of a database of simulated radargrams representing the possible scenarios during the RS acquisition. The database is analyzed to predict the RS performance, to design the instrument parameters, and to support the development of automatic target detection algorithms. To demonstrate the proposed techniques the thesis addresses their use in two future RS instruments, which are at different phases of development: (1) the Radar for Icy Moons Exploration (RIME) and (2) a RS for Earth observation of the polar ice caps. The first contribution focuses on the analysis of the detectability of complex tectonic targets on the icy moons of Jupiter by RIME by simulating the radar response of 3D target models. The second contribution presents a feasibility study for an Earth orbiting RS based on the proposed simulation approaches.

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A new task analysis methodology was developed to provide objective information on complex tasks. A complex task was broken down into observable elements and unobservable elements that were inferred to have taken place in support of the observable actions. Subject matter experts (SMEs) were used to assist in this breakdown. Additionally, guidelines for specifying the level of detail in the task analysis breakdown were developed to help objectify the analysis. A simulation model framework then was built of the task elements. Personnel proficient in the task were observed during work, and objective data on their observable actions were collected. These data then were used to provide numeric input to a simulation model. The simulation was run, and the results of the model of performance compared to the observed performance data. The model was altered at that point to reflect lessons learned during data collection. The process yielded a model that accurately reflects human performance on the task. Variations on the model based on a conceptual understanding of operators strategies also correlated well with observed performance, indicating the value of the methodology for building an understanding of the motivations critical to successful task performance. / Ph. D.

A floating treatment wetland (FTW) is an ecological approach which seeks to reduce point and nonpoint source pollution by installing substrate rooted plants grown on floating mats in open waters. While relatively novel, FTW use is increasing. A review of literature identified several research gaps, including: (1) assessments of the treatment performance of FTWs; (2) evaluations of FTWs in the U.S., particularly within wet ponds that receive urban runoff; and (3) plant temporal nutrient distribution, plant growth rate, and the long-term persistence of the FTWs in temperate regions with periodic ice encasement. An assessment model, i-FTW model, was developed, and its parameter s fitted based on data from 14 published FTW studies in the first research topic. The estimated median FTW apparent uptake velocity with 95% confidence interval were 0.048 (0.018 - 0.059) and 0.027 (0.016 - 0.040) m/day for total phosphorus (TP) and total nitrogen (TN), respectively. The i-FTW model provided a more accurate prediction in nutrient removal than two common performance metrics: removal rate (mg/m2/day) and removal efficiency (%). In the second research topic, the results of a mesocosm experiment indicated that FTWs with 61% coverage, planted with pickerelweed (Pontederia cordata L.) or softstem bulrush (Schoenoplectus tabernaemontani), significantly improved TP and TN removal efficiency of the control treatment by 8.2% and 18.2%, respectively. The pickerelweed exhibited significantly higher phosphorus and nitrogen removal than the softstem bulrush when water temperatures were greater than 25 deg C. Field observations in the third research topic found that pickerelweed demonstrated higher phosphorus removal performance (7.58 mg/plant) than softstem bulrush (1.62 mg/plant). Based on the observed seasonal changes in phosphorus distribution, harvest of above-ground vegetation is recommended to be conducted twice a year in June and September. Planted perennial macrophytes successfully adapted to stresses of the low dissolved oxygen (DO) concentrations (minimum: 1.2 mg/L), ice encasement, and relatively low nutrient concentrations in the water (median: 0.15 mg/L TP and 1.15 mg/L TN). Systematic observation of wildlife activities indicated eight classes of organisms inhabiting, foraging, breeding, nursing, or resting in the FTWs. Recommendations for FTW design and suggestions for further research are made based upon these findings. / Ph. D.

Thesis (PhD)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: This study investigates the construction of Performance Assessment Discourses in three companies in the Western Cape, South Africa. The specific interest of is in how Performance Assessment Interviews (PAIs) are performed in terms of content, form, structure and social practice, and how managers and employees experience and make sense of this organizational practice. The study further investigates how individuals express their membership to communities of practice (CofPs) within the workplace, and seeks to identify obstacles (boundaries) in terms of acquiring and maintaining membership. This study is conducted within the broader framework of discourse analysis (DA) and employs genre theory and small story analysis as analytical tools. The 31 participants in this study are managers and employees of three participating companies in the Western Cape. They are L1 speakers of Afrikaans, English, isiXhosa and isiZulu, and are representative of a wide range of employment levels (lower-level employees to top management). Each individual participated in either a one-on-one interview or in a focus group discussion, which were audio-recorded and transcribed. During these interviews and discussion groups, individuals frequently resorted telling small stories in order to explicate their feelings, perceptions and positions on certain matters. The data confirms that several generic features of PAIs are identifiable and across all three companies, but that some unique features are also reported. Furthermore, the analysis shows that Performance Assessments are sites of struggles as dominant and competing discourses emerge from the data. Additionally, the study reveals that acquiring membership to CofPs in a diverse workplace is a complex endeavour and that language plays a determining role in acquiring membership, as well as in the construction of workplace identities. In conclusion, this study argues for further linguistic research within professional setting in South Africa, and suggests that CofP theory be revised and further developed to be more descriptive of diverse communities. / AFRIKAANSE OPSOMMING: Hierdie studie ondersoek hoe Prestasiebestuur (PB) diskoerse in drie maatskappye in die Wes-Kaap gekonstrueer word. Die studie stel spesifiek belang in hoe prestasiebestuur gesprekke (PBG) uitgevoer word in terme van inhoud, vorm, struktuur en die sosiale praktyke wat daarmee saamhang. Verder word die manier waarop bestuurders en werkers PBGs ervaar en interpreteer ondersoek. Die studie ondersoek ook hoe individue hul lidmaatskap tot praktyk gemeenskappe (verskeie groeperinge wat praktyke deel) binne die werksplek beskryf en die struikelblokke identifiseer wat hulle verhoed om lidmaatskap te verwerf en te behou. Hierdie studie is uitgevoer binne die breër raamwerk van diskoersanalise (DA) en gebruik genre analise en klein verhaal analise as ontledingsmetodes. Die 31 deelnemers in die studie is bestuurders en werkers van drie deelnemende maatskappye in die Wes-Kaap. Hulle is eerstetaalsprekers van Afrikaans, Engels, Xhosa en Zoeloe en is verteenwoordigend van ʼn wye reeks posisies (vanaf junior posisies tot topbestuur). Elke individu het deelgeneem aan óf ʼn individuele onderhoud óf ʼn groepsbespreking. Hierdie onderhoude en besprekings is opgeneem en getranskribeer. Tydens die onderhoude en besprekings het die deelnemers telkens van ‘klein verhale’ gebruik gemaak om hul ervaringe en gevoelens te verwoord. Die data bevestig dat verskeie generiese eienskappe in PBGs geïdentifiseer kan word in al drie maatskappye maar dat daar wel sommige unieke eienskappe voorkom. Verder wys die analise uit dat binne PBs daar baie teenstellings bestaan en dat daar dominante en mededingende diskoerse in die data geïdentifiseer kan word. Die studie wys ook dat lidmaatskap tot ʼn praktykgemeenskap in ʼn diverse werksomgewing ʼn komplekse onderneming is. Dit blyk ook dat taal ʼn bepalende rol speel in die verwerwing van lidmaatskap, sowel as die manier waarop professionele identiteit gekonstrueer word. Verdere navorsing in professionele kontekste binne ʼn linguistiese raamwerk word aanbeveel. Die waarde van klein verhaal analise om diskoerse in professionele kontekste te ondersoek word beklemtoon en voorstelle word gemaak oor hoe die konsep ‘praktykgemeenskappe’ verder ontwikkel kan word om dit meer relevant te maak in die Suid-Afrikaanse konteks. / The ADA for funding this study

Proximal stability, or the ability to stabilize and actively control the spine, pelvis and trunk, has been reported to influence sport performance. Traditional training practices for the proximal segments have had little success improving sport performance. The purpose of this dissertation was to investigate the effects a sport specific proximal stability training program can have on throwing velocity and measures of muscular endurance and power which target the proximal segments of the pelvis, spine and trunk. A stratified randomized clinical trial was implemented with a pre- to post-intervention design. Forty-six healthy, Division III collegiate female softball (n=17) and male baseball (n=29) players were randomly assigned to one of two training groups for 7 weeks; a traditional endurance training group (ET) (n=21) or a power stability training group (PS) (n=25). The primary outcome measures were the change in peak throwing velocity/Kg of body weight in mph. Mean throwing velocity, power outputs from a one-repetition maximum chop test and lift test (watts/Kg body weight), and muscular endurance plank tests. Student’s independent t-tests were used to compare differences between change scores of all dependent variables. Peak throwing velocity change scores were significantly faster (ET= .21 ±.55 mph, PS= 3.4 ±1.1 mph, p< .001) in the PS at post-intervention when compared to the ET group. Change scores were significantly greater in the PS group for mean throwing velocity, (ET= 1.1 ±1.6 mph vs. PS= 3.7 ±1.8 mph, p< .001), chop (watts), (ET= 20 ±78 watts vs. PS= 105 ±68 watts, p< .001), and lift, (ET= 49 ±62 watts vs. PS= 114 ±73 watts, p= .003). There were no change score differences for the side and prone plank endurance measures in seconds (p≥ .60). The PS group increased primary outcome measures over the ET program, indicating a more sport specific training regimen targeting the proximal segments is beneficial to both the power measures and throwing performance.

<p> </p><p>The purpose of this thesis is to understand the opinions and potential effects of objective and subjective assessments of performance as a basis for performance pay for blue-collar workers.</p><p>The study takes a qualitative approach to find out how and why four companies - Trelleborg Forsheda, Finnveden Powertrain, Isaberg Rapid and Parker Hannifin- work with salaries, incentive system and performance assessment the way they do.</p><p>The concept of individual salary is central in this thesis, and individual salary is based on four criteria; capabilities, performance, work demand and formal competence. These can be divided in subjective or objective criteria. Individual salaries also contribute to salary divergence, which in many studies have indicated higher performance. Important to remember is that it has to exist a purpose to salary divergence and how salary is diverged in the company is related to the goals and strategy of the company. If the company chooses to have performance based salaries- which is salary divergence- another question arise; what is good performance?</p><p>In organizations that have performance salaries, a group or an individual (often the middle manager) have to decide if a certain group of personnel performs good or bad. This can mainly be done in two different ways; objective performance assessment or subjective performance assessment. Objective performance assessment is based on numerical calculation of measures, which will form the basis for rewarding employees using a salary system that reward performance. Subjective performance measurements are based on judgment. Instead of relying on numerical calculations, one evaluates if the results reflect good or bad performance.</p><p>For both methods it is essential that the personnel feels that the salaries are fair, and that the salary system is clear and easy to understand. Something else that is important to understand is that employer and employee have different views in what is a fair salary.</p><p>Objective assessments are based on numerical calculations of measures, and one important property such measures have is that they don’t leave any room for excuses. Research indicate that performance pay has important motivation enhancing effects, but the profitability doesn’t always benefit from it. When monitoring costs are high, or product quality or long term thinking is required, hourly wages may be preferable. Tasks which are measured, will naturally be prioritized by the organization. This means that the choice of measures is very important. The amount of measures mustn’t be too high, and they have to be carefully considered. Subjective assessments are the opposite to objective ones. The advantages with subjective performance assessments are, among other things, that additional information which have surfaced during the period of measurements can be taken into consideration, errors in the measurement process can be corrected and unlucky circumstances can be dealt with. However, problems exist in unfair assessments, which are based on prejudice.</p><p>Findings in this report shows that profitable companies have large differences in their salary systems. This is also supported by other research. The company Isaberg Rapid AB only uses objective criteria, focused on simplicity and group rewards. Finnveden Powertrain on the other hand, has a system focused on individuals and subjective assessments. Some conclusions could be drawn; one of the most important being that connections between the type of activities and the salary system is positive, and that salary systems have to be updated and revised continuously.</p><p> </p>

Accurate wave measurements are required for wave energy applications, including resource assessments and performance assessments. In response, wave data are measured from deployment sites, commonly using wave buoys or other point wave sensors. Spatial variability in the wave field will introduce inaccuracies to the analysis of data captured from a single point to represent a separate location or area. This thesis describes research undertaken to quantify the effect of spatial variability on the accuracy of direct wave measurements taken at a wave energy site. An array of four timesynchronised wave buoys were deployed, separated by 500m, in a location close to the Wave Hub wave energy test site in Cornwall, UK. These data were subject to close scrutiny in terms of data processing and quality control, which raised specific issues regarding data processing and the validation of wave data for a new measurement facility. Specific recommendations are made for data captured from this facility, and bespoke quality control routines were developed. This process minimises the possible contribution of errors to the processed data, which is observed to be of the highest importance when analysing simultaneous data sets, and provides a data set that is particularly suited to the examination of the spatial characteristics of ocean waves. The differences between simultaneous data demonstrated local physical processes to be causing a deterministic difference between the waves at the measurement sites, which contributed to a significant difference between the power statistics at different locations within the site. Instantaneous differences between measurements were observed to agree well with theoretical estimations of random error, based on sampling theory. The culmination of the research is a unique analysis of the spatial properties of ocean wave fields on the scale of a wave energy test site, of direct relevance to the development and monitoring of wave energy test sites.