No / Surveys are a common method of data collection within health service research. An essential aspect of reporting survey research is ensuring that sufficient information is provided to enable readers to determine the validity and representativeness of research findings. Method This study reports a secondary analysis of survey research published in Radiography and Clinical Radiology between 2001 and 2010. The purpose of the study was to evaluate trends in response rates and establish how non-response bias was being addressed. Results Analysis of non-response bias was undertaken in 9.4% (n = 9/96) of studies. Where analysis was performed, strong reliance on demographic characteristics to determine sample representativeness was noted (n = 8/9; 88.9%). Conclusion The findings of this study suggest that non-response bias is not being adequately addressed within published imaging related survey research and more needs to be done to encourage a rigorous approach to the analysis and reporting of survey results.

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.

This thesis addresses the problem of automatic speech recognition, specifically, how to transform an acoustic waveform into a string of words or phonemes. A preliminary chapter gives linguistic information potentially useful in automatic speech recognition. This is followed by a description of the Wave Analysis Laboratory (WAL), a rule-based system which detects features in speech and was designed as the acoustic front end of a speech recognition system. Temporal reasoning as used in WAL rules is examined. The use of WAL in recognizing one particular class of speech sounds, the nasal consonants, is described in detail. The remainder of the thesis looks at the statistical analysis of samples of spontaneous speech. An orthographic transcription of a large sample of spontaneous speech is automatically translated into phonemes. Tables of the frequencies of word initial and word final phoneme clusters are constructed to illustrate some of the phonotactic constraints of the language. Statistical data is used to assign phonemes to phonotactic classes. These classes are unlike the acoustic classes, although there is a general distinction between the vowels, the consonants and the word boundary. A way of measuring the phonetic balance of a sample of speech is described. This can be used as a means of ranking potential test samples in terms of how well they represent the language. A phoneme n-gram model is used to measure the entropy of the language. The broad acoustic encoding output from WAL is used with this language model to reconstruct a small test sample. "Branching" a simpler alternative to perplexity is introduced and found to give similar results to perplexity. Finally, the drop in branching is calculated as knowledge of various sets of acoustic classes is considered. In the work described in this thesis the main contributions made to automatic speech recognition and the study of speech are in the development of the Wave Analysis Laboratory and in the analysis of speech from a phonotactic point of view. The phoneme cluster frequencies provide new information on spoken language, as do the phonotactic classes. The measures of phonetic balance and branching provide additional tools for use in the development of speech recognition systems.

The primary objective of the presented research is to develop a class of integrated compact silicon diffractive sensors (CSDS) based on in-plane diffraction gratings. This class of sensors uses a silicon-on-insulator (SOI) substrate to limit costs, exploit established fabrication processes, enable integration of supporting electronics, and use the well-understood telecommunications wavelength of 1.55µm. Sensing is achieved by combining constant-diffraction-efficiency and highly-angularly-selective in-plane resonance-domain diffraction gratings. Detection is based on the diffraction efficiency of the highly angularly selective grating. In this research, the design processes for the constant-diffraction-efficiency and the highly angularly selective gratings are detailed. Grating designs are optimized with rigorous coupled-wave analysis (RCWA) and simulated with finite-difference time-domain (FDTD) analysis. Fabrication results are presented for the CSDS gratings. An inductively coupled plasma (ICP) Bosch etch process enables grating fabrication to within one percent of designed values with nearly vertical sidewalls. Experimental results are presented for individual CSDS gratings, the prototype sensor, and a prototype linear sensor array. The results agree well with simulation. The linear sensor array prototype demonstrates the intrinsic splitting mechanism and forms the basis of a 2-D sensor array. Finally, a toluene sensor was functionally demonstrated. The proof-of-concept device includes a polymer immobilization layer and microfluidic delivery of toluene. Toluene concentrations as low as 100ppm are measured, corresponding to a refractive index change of 3x10⁻⁴ RIU.

Kyoto University (京都大学) / 0048 / 新制・課程博士 / 博士(工学) / 甲第15356号 / 工博第3235号 / 新制||工||1487(附属図書館) / 27834 / 京都大学大学院工学研究科都市環境工学専攻 / (主査)教授 間瀬 肇, 教授 後藤 仁志, 准教授 森 信人 / 学位規則第4条第1項該当

The Multichannel Analysis of Surface Waves (MASW) method traditionally uses an array of collinear vertical geophones to measure seismic wave propagation velocity at discrete points along the ground surface. Distributed fiber optic sensors (FOS) measure the average longitudinal strain over discrete lengths (i.e., zones) of a buried fiber optic cable. Such strain measurements can be used to assess ground motion and thus analyzed with the MASW method. To evaluate the feasibility of using FOS strain measurements in the MASW method, field experiments were conducted with both FOS and surface vertical geophones. Synthetic seismograms were also used to compare FOS to vertical and horizontal geophones and investigate the effect of installation depth and sensor type. Through the MASW method, shear wave (Vs) profiles from the FOS showed comparable results to those obtained with the geophones and achieved the same degree of uncertainty from the non-uniqueness of the MASW inversion process.

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This dissertation provides a comprehensive methodology for accurate analysis and design of miniaturized radio frequency (RF) surface acoustic wave (SAW) duplexer package. Full-wave analysis based on the three dimensional (3-D) finite element method (FEM) is successfully applied to model the package. The die model is obtained by combining the acoustics and die busbars parasitics models. The acoustics model is obtained using the coupling-of-models (COM) technique. The die busbars, bonding wires and printed circuit board (PCB) are modeled using full-wave analysis. After that, the models of package, die, and bonding wires are assembled together to get the total response. To take into account the mutual couplings, the methodology is extended to model the package, die busbars, and bonding wires together. The advantages and disadvantages of the methodology are also discussed. Based on the methodology, the Korea personal communication system (KPCS) duplexer is analyzed and designed. The isolation of KPCS duplexer package is significantly improved by redesigning inner ground plane, bonding wire scheme and ground via. A KPCS duplexer package is designed and excellent transmitter to receiver isolation in the transmission band is achieved. Simulation and measurement results are compared, and excellent agreement is found. Although we focus on investigating the methods to improve the isolation, the passband performance is also improved. The methodology is also successfully used for flip chip duplexer. The simulation results from our assembling method match the measurement results very well. Optimization method is applied to improve the transmit band isolation. With the new package and die design, the transmit band isolation can be improved from -53.6 dB to -65.2 dB. Based on the new package, the effect of the Rx ground trace on the isolation is investigated and the transmit band isolation can achieve -67.3 dB with the modification of the Rx ground trace. The technique developed in this dissertation reduces the design cycle time greatly and can be applied to various RF SAW device packages.

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