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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
141

The use of rubrics and correction codes in the marking of Grade 10 Sesotho home language creative writing essays

Sibeko, Johannes January 2015 (has links)
This study investigates the assessment of creative essays in grade 10 Sesotho home language. Nine participants from a total of six schools took part in the research. For the purpose of this study, no literature was found on the assessment of Sesotho essays (or essay writing in any other African language) in general or specific to creative writing in high schools in South Africa. The literature on English first language teaching and English second language teaching were then used to theoretically contextualise the writing and assessment of creative writing essays in Sesotho home language in South African high schools. Data were collected through questionnaires completed by teachers, an analysis of a sample of marked scripts (representing above average, average and below average grades) and interviews with teachers (tailored to investigate the asset of creativity and the aspect of style in Sesotho creative writing essays). The researcher manually coded open-ended responses in the questionnaires. Interview responses were coded with Atlas.ti version 7. Frequencies were calculated for the close-ended questions in the questionnaire. Participating teachers perceived their assessment of essays with the use of the rubric and the correction to be standardised. This was evident in their awarding of marks. It was found in this study that teachers generally award marks around 60%. However, their report that they use comments as per their responses in the questionnaire was disproven by the lack of comments in the scripts analysed in this study. There was also no relationship observed between the correction code frequencies observed in the marked essays that were analysed and the marks granted for specific sections of the rubric. This study recommends use of the rubric in earlier drafts of the writing process. In addition, it proposes an expansion of the marking grid used to provide clearer feedback via the revised rubric to the learners. Due to the participating teachers’ evident lack of clarity on what style in Sesotho home language essays entail, it was inferred that teachers are not clear on the distinctions between different essay assessment criteria in the rubric. A recommendation was the development of a rubric guide, which would clearly indicate to teachers what each criterion of the rubric assesses.
142

ENHANCING THE PCM/FM LINK - WITHOUT THE MATH

Fewer, Colm, Wilmot, Sinbad 10 1900 (has links)
ITC/USA 2007 Conference Proceedings / The Forty-Third Annual International Telemetering Conference and Technical Exhibition / October 22-25, 2007 / Riviera Hotel & Convention Center, Las Vegas, Nevada / Since the 1970s PCM/FM has been the dominant modulation scheme used for RF telemetry. However more stringent spectrum availability as well as increasing data rates means that more advanced transmission methods are required to keep pace with industry demands. ARTM Tier-I and Tier-II are examples of how the PCM/FM link can be enhanced. However these techniques require a significant increase in the complexity of the receiver/detector for optimal recovery. This paper focuses on a quantitative approach to improving the rate and quality of data using existing PCM/FM links. In particular ACRA CONTROL and BAE SYSTEMS set themselves the goal of revisiting the pre-modulation filter, diversity combiner and bit-sync. By implementing programmable adaptive hardware, it was possible to explore the various tradeoffs offered by modifying pulse shapes and spectral occupancy, inclusion of forward error correction and smart source selection. This papers looks at the improvements achieved at each phase of the evaluation.
143

ERROR DETECTION AND CORRECTION -- AN EMPIRICAL METHOD FOR EVALUATING TECHNIQUES

Rymer, J. W. 10 1900 (has links)
International Telemetering Conference Proceedings / October 23-26, 2000 / Town & Country Hotel and Conference Center, San Diego, California / This paper describes a method for evaluating error correction techniques for applicability to the flight testing of aircraft. No statistical or math assumptions about the channel or sources of error are used. An empirical method is shown which allows direct “with and without” comparative evaluation of correction techniques. A method was developed to extract error sequences from actual test data independent of the source of the dropouts. Hardware was built to allow a stored error sequence to be repetitively applied to test data. Results are shown for error sequences extracted from a variety of actual test data. The effectiveness of Reed-Solomon (R-S) encoding and interleaving is shown. Test bed hardware configuration is described. Criteria are suggested for worthwhile correction techniques and suggestions are made for future investigation.
144

STANDARD INTEROPERABLE DATALINK SYSTEM, ENGINEERING DEVELOPMENT MODEL

Cirineo, Tony, Troublefield, Bob 11 1900 (has links)
International Telemetering Conference Proceedings / October 30-November 02, 1995 / Riviera Hotel, Las Vegas, Nevada / This paper describes an Engineering Development Model (EDM) for the Standard Interoperable Datalink System (SIDS). This EDM represents an attempt to design and build a programmable system that can be used to test and evaluate various aspects of a modern digital datalink. First, an investigation was started of commercial wireless components and standards that could be used to construct the SIDS datalink. This investigation lead to the construction of an engineering developmental model. This model presently consists of wire wrap and prototype circuits that implement many aspects of a modern digital datalink.
145

AN INTRODUCTION TO LOW-DENSITY PARITY-CHECK CODES

Moon, Todd K., Gunther, Jacob H. 10 1900 (has links)
International Telemetering Conference Proceedings / October 20-23, 2003 / Riviera Hotel and Convention Center, Las Vegas, Nevada / Low-Density Parity-Check (LDPC) codes are powerful codes capable of nearly achieving the Shannon channel capacity. This paper presents a tutorial introduction to LDPC codes, with a detailed description of the decoding algorithm. The algorithm propagates information about bit and check probabilities through a tree obtained from the Tanner graph for the code. This paper may be useful as a supplement in a course on error-control coding or digital communication.
146

EXTENDING THE RANGE OF PCM/FM USING A MULTISYMBOL DETECTOR AND TURBO CODING

Geoghegan, Mark 10 1900 (has links)
International Telemetering Conference Proceedings / October 21, 2002 / Town & Country Hotel and Conference Center, San Diego, California / It has been shown that a multi-symbol detector can improve the detection efficiency of PCM/FM by 3 dB when compared to traditional methods without any change to the transmitted waveform. Although this is a significant breakthrough, further improvements are possible with the addition of Forward Error Correction (FEC). Systematic redundancy can be added by encoding the source data prior to the modulation process, thereby allowing channel errors to be corrected using a decoding circuit. Better detection efficiency translates into additional link margin that can be used to extend the operating range, support higher data throughput, or significantly improve the quality of the received data. This paper investigates the detection efficiency that can be achieved using a multisymbol detector and turbo product coding. The results show that this combination can improve the detection performance by nearly 9 dB relative to conventional PCM/FM systems. The increase in link margin is gained at the expense of a small increase in bandwidth and the additional complexity of the encoding and decoding circuitry.
147

Enhancing the design-manufacturing interface in nanoscale technologies

Banerjee, Shayak 08 October 2010 (has links)
Semiconductor scaling has been largely driven by advancements in lithographic technologies. However, the lack of a viable next generation lithography solution since the 180nm node has driven the industry to printing sub-wavelength features. This has led to rising manufacturing costs and diminishing chip yield. In traditional methodologies, manufacturing and design are relatively insulated, with a layout being the only means of communicating design intent to the foundry. In this dissertation, we describe several techniques which utilize electrical information to improve properties of manufactured structures. We aim to show that a bi-directional flow of information between design and manufacturing is key to increasing chip yield. In particular, we target the mask data preparation flow of lithography. We develop an electrically-driven optical proximity correction (ED-OPC) tool that performs electrical matching as opposed to geometric matching in order to achieve lower post-lithography delay error. We then demonstrate how to harness ED-OPC to compensate electrical variability arising from non-lithographic sources as well. We then describe a technique to manufacture circuits with less timing violations across the process window by using design-aware shape tolerances generated from timing information. Finally, we observe that local wiring has low impact on design properties and use this information to modify target wire shapes themselves in order to improve their manufacturability in the presence of process variations. / text
148

The "Many Fragments Curse:" A Special Case of the Segment Length Curse

Sheppard, Paul R., Holmes, Richard L., Graumlich, Lisa J. January 1997 (has links)
The "many fragments curse," a special case of the segment length curse, occurs in den- drochronology when time series are broken into fragments, either because of missing part of a sample (e.g., a rot pocket) or when a section of ring growth cannot be crossdated (e.g., a section with extremely suppressed growth and/or many rings absent). We exorcise this curse by inserting values to connect fragments of measurements. This technique permits fitting a single detrending curve to the connected series and thus preserves the low-frequency variance contained in the entire series. Inserted values are discarded after detrending and do not otherwise affect calculations of final corn- posite chronologies. As an example from junipers sampled at a site in Qinghai Province, China, 66 of 117 increment cores have nondatable sections of wood and one core has a gap of rotten wood between dated fragments. After connecting fragments by inserting values and then detrending, the chronology constructed from connected fragments has stronger century to multicentury scale variation than the chronology constructed from separate fragments. This approach is adapted to the library of computer programs developed for dendrochronological research under the auspices of the International Tree-Ring Data Bank.
149

Real-time Cycle-slip Detection and Correction for Land Vehicle Navigation using Inertial Aiding

Karaim, MALEK 07 May 2013 (has links)
Processing GPS carrier-phase measurements can provide high positioning accuracy for several navigation applications. However, if not detected, cycle slips in the measured phase can strongly deteriorate the positioning accuracy. Cycle slips frequently occur in areas surrounded by trees, buildings, and other obstacles. The dynamics experienced by the GPS receiver in kinematic mode of navigation also increases the possibility of cycle slips. Detection and correction of these cycle-slips is essential for reliable navigation. One way of detecting and correcting for cycle slips is to use another system to be integrated with GPS. Inertial Navigation Systems (INS), using three-axis accelerometers and three-axis gyroscopes, is integrated with GPS to provide more reliable navigation solution. Moreover, INS was utilized in the past for GPS cycle slip detection and correction. For low cost applications, Micro-Electro-Mechanical-Systems (MEMS) accelerometers and gyroscopes are used inside INS. For land navigation, reduced inertial sensor system (RISS) utilizing two accelerometers, one gyroscope, and the vehicle odometer was suggested. MEMS-based RISS has the advantage of using less number of MEMS-based gyroscopes and accelerometers thus reducing the overall cost and avoiding the complex error characteristics associated with MEMS sensors. In this thesis, we investigate the use of MEMS – based RISS to aid GPS and detect and correct for cycle slips. The Kalman filter was employed in centralized fashion to integrate the measurements from both GPS and RISS. This thesis research also offers a new threshold selection criterion resulting in a more robust cycle slip detection and correction. The proposed method was tested in different scenarios of road tests in land vehicle. Results show accuracy iii improvement over the conventional double differenced pseudoranges-based integrated system. Moreover, the adaptive selection criterion of the detection threshold proposed in this thesis improves the detection rate, especially in the case of small-sized cycle slips. / Thesis (Master, Electrical & Computer Engineering) -- Queen's University, 2013-05-06 18:11:57.076
150

Electrical test structures and measurement techniques for the characterisation of advanced photomasks

Tsiamis, Andreas January 2010 (has links)
Existing photomask metrology is struggling to keep pace with the rapid reduction of IC dimensions as traditional measurement techniques are being stretched to their limits. This thesis examines the use of on-mask probable electrical test structures and measurement techniques to meet this challenge and to accurately characterise the imaging capabilities of advanced binary and phase-shifting chrome-on-quartz photomasks. On-mask, electrical and optical linewidth measurement techniques have highlighted that the use of more than one measurement method, complementing each other, can prove valuable when characterising an advanced photomask process. Industry standard optical metrology test patterns have been adapted for the direct electrical equivalent measurement and the structures used to characterise different feature arrangements fabricated on standard and advanced photomasks with proximity correction techniques. The electrical measurements were compared to measurements from an optical mask metrology and verification tool and a state-of-the-art CD-AFM system and the results have demonstrated the capability and strengths of the on-mask electrical measurement. For example, electrical and AFM measurements on submicron features agreed within 10nm of each other while optical measurements were offset by up to 90nm. Hence, electrical techniques can prove valuable in providing feedback to the large number of metrology tools already supporting photomask manufacture, which in turn will help to develop CD standards for maskmaking. Electrical test structures have also been designed to enable the characterisation of optical proximity correction to characterise right angled corners in conducting tracks using a prototype design for both on-mask and wafer characterisation. Measurement results from the on-mask structures have shown that the electrical technique is sensitive enough to detect the effect of OPC on inner corners and to identify any defects in the fabricated features. For example less than 10 (5%) change in the expected resistance data trends indicated a deformed OPC feature. Results from on-wafer structures have shown that the correction technique has an impact on the final printed features and the measured resistance can be used to characterise the effects of different levels of correction. Overall the structures have shown their capability to characterise this type of optical proximity correction on both mask and wafer level. Test structures have also been designed for the characterisation of the dimensional mismatch between closely spaced photomask features. A number of photomasks were fabricated with these structures and the results from electrical measurements have been analysed to obtain information about the capability of the mask making process. The electrical test structures have demonstrated the capability of measuring tool and process induced dimensional mismatches in the nanometer range on masks which would otherwise prove difficult with standard optical metrology techniques. For example, electrical measurements detected mismatches of less than 15nm on 500nm wide features.

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