One of the most important parameters of speech is the fundamental frequency of vibration of voiced sounds. The audio sensation of the fundamental frequency is known as the pitch. Depending on the tonal/non-tonal category of language, the fundamental frequency conveys intonation, pragmatics and meaning. In addition the fundamental frequency and intonation carry speaker gender, age, identity, speaking style and emotional state. Accurate estimation of the fundamental frequency is critically important for functioning of speech processing applications such as speech coding, speech recognition, speech synthesis and voice morphing. This thesis makes contributions to the development of accurate pitch estimation research in three distinct ways: (1) an investigation of the impact of the window length on pitch estimation error, (2) an investigation of the use of the higher order moments and (3) an investigation of an analysis-synthesis method for selection of the best pitch value among N proposed candidates. Experimental evaluations show that the length of the speech window has a major impact on the accuracy of pitch estimation. Depending on the similarity criteria and the order of the statistical moment a window length of 37 to 80 ms gives the least error. In order to avoid excessive delay as a consequence of using a longer window, a method is proposed ii where the current short window is concatenated with the previous frames to form a longer signal window for pitch extraction. The use of second order and higher order moments, and the magnitude difference function, as the similarity criteria were explored and compared. A novel method of calculation of moments is introduced where the signal is split, i.e. rectified, into positive and negative valued samples. The moments for the positive and negative parts of the signal are computed separately and combined. The new method of calculation of moments from positive and negative parts and the higher order criteria provide competitive results. A challenging issue in pitch estimation is the determination of the best candidate from N extrema of the similarity criteria. The analysis-synthesis method proposed in this thesis selects the pitch candidate that provides the best reproduction (synthesis) of the harmonic spectrum of the original speech. The synthesis method must be such that the distortion increases with the increasing error in the estimate of the fundamental frequency. To this end a new method of spectral synthesis is proposed using an estimate of the spectral envelop and harmonically spaced asymmetric Gaussian pulses as excitation. The N-best method provides consistent reduction in pitch estimation error. The methods described in this thesis result in a significant improvement in the pitch accuracy and outperform the benchmark YIN method.

This research project deals with dynamic field testing of light-frame wood buildings with wood based shear walls. The primary objective of the investigation is to evaluate the code formula for estimating light wood frame building’s fundamental period, through intensive field testing and numerical modelling. The project also aims to propose an alternative simplified rational approach where applicable. The thesis provides insight to the ambient vibration testing procedures of light-frame wood buildings and explains the protocol adopted for the current research program. Ambient vibration (AV) field tests were conducted on several multi-storey wood and beam-and-post buildings in Canada. Modal parameters of measured buildings, such as natural frequency, mode shapes and equivalent structural damping were obtained from Frequency Domain (FD) analysis of ambient motion records. Experimental and numerical investigations were performed to evaluate the effect of non-structural components, and the connectivity between firewall-separated buildings, on dynamic properties of light-frame wood buildings. The study provides a reliable expression for building period estimate based on field testing and numerical modeling.

A two-phase study was undertaken to investigate the fundamental period of concentrically braced steel frames (CBFs) designed according to Eurocode 8. In the first phase, typical office buildings were studied by conducting two types of designs which are called as iterative and non-iterative. Non-iterative design is composed of obtaining final period by designing the structure with lower bound expression in Eurocode 8 while iterative design is similar to the non-iterative one but an updating of periods was considered in order to converge assumed and final periods. Different overstrength provisions are considered in the study. Lower bound expression in Eurocode 8 results in shorter periods which indicates that this expression can be safely utilized. The lower bound represented by Tremblay (2005) is also admissible except for some cases including shorter periods. In the second phase, a simple expression is derived for estimating the design base acceleration for braced frames proportioned according to Eurocode 8. This method requires inelastic top story drift values which were obtained from structures designed in the first phase using iterative method. These drifts were represented by simple expressions utilizing data fitting techniques. The method gives suitable first order estimate for the design base acceleration.

In many seismic design codes and provisions, such as Uniform Building Code and Turkish Seismic Code, prediction of fundamental period of shear-wall dominant buildings, constructed by tunnel form technique, to compute the anticipated seismic forces is achieved by empirical equations considering the height of the building and ratio of effective shear-wall area to first floor area as the primary predictor parameters. However, experimental and analytical studies have collectively indicated that these empirical formulas are incapable of predicting fundamental period of shear-wall dominant buildings, and consequently result in erroneous computation of design forces. To compensate for this deficiency, an effective yet simple formula has recently been developed by Balkaya and Kalkan (2004), and tested against the data from ambient surveys on existing shear-wall dominant buildings. In this study, previously developed predictive equation is modified to include the effects of soil-structure interaction on the fundamental period. For that purpose, 140 shear-wall dominant buildings having a variety of plans, heights and wall-configurations were re-analyzed for four different soil conditions classified according to NEHRP. The soil effects on the foundation were represented by the translational and rotational springs, and their rigidities were evaluated from foundation size and elastic uniform compressibility of soil. Based on the comprehensive study conducted, improved prediction of fundamental period is achieved. The error in predictions on average is about 15 percent, and lending further credibility to modified formula considering soil-structure interaction to be used in engineering practice.

The construction of reinforced concrete buildings with unreinforced infill is common practice even in seismically active country such as Bhutan, which is located in high seismic region of Eastern Himalaya. All buildings constructed prior 1998 were constructed without seismic provisions while those constructed after this period adopted seismic codes of neighbouring country, India. However, the codes have limited information on the design of infilled structures besides having differences in architectural requirements which may compound the structural problems. Although the influence of infill on the reinforced concrete framed structures is known, the present seismic codes do not consider it due to the lack of sufficient information. Time history analyses were performed to study the influence of infill on the performance of concrete framed structures. Important parameters were considered and the results presented in a manner that can be used by practitioners. The results show that the influence of infill on the structural performance is significant. The structural responses such as fundamental period, roof displacement, inter-storey drift ratio, stresses in infill wall and structural member forces of beams and column generally reduce, with incorporation of infill wall. The structures designed and constructed with or without seismic provision perform in a similar manner if the infills of high strength are used.