Matching Items (3)

156974-Thumbnail Image.png

Separation of Agile Waveform Time-Frequency Signatures from Coexisting Multimodal Systems

Description

As the demand for wireless systems increases exponentially, it has become necessary

for different wireless modalities, like radar and communication systems, to share the

available bandwidth. One approach to realize coexistence successfully

As the demand for wireless systems increases exponentially, it has become necessary

for different wireless modalities, like radar and communication systems, to share the

available bandwidth. One approach to realize coexistence successfully is for each

system to adopt a transmit waveform with a unique nonlinear time-varying phase

function. At the receiver of the system of interest, the waveform received for process-

ing may still suffer from low signal-to-interference-plus-noise ratio (SINR) due to the

presence of the waveforms that are matched to the other coexisting systems. This

thesis uses a time-frequency based approach to increase the SINR of a system by estimating the unique nonlinear instantaneous frequency (IF) of the waveform matched

to the system. Specifically, the IF is estimated using the synchrosqueezing transform,

a highly localized time-frequency representation that also enables reconstruction of

individual waveform components. As the IF estimate is biased, modified versions of

the transform are investigated to obtain estimators that are both unbiased and also

matched to the unique nonlinear phase function of a given waveform. Simulations

using transmit waveforms of coexisting wireless systems are provided to demonstrate

the performance of the proposed approach using both biased and unbiased IF estimators.

Contributors

Agent

Created

Date Created
  • 2018

155186-Thumbnail Image.png

Analyzing the distribution and variations in construction costs for commercial tenant improvement projects

Description

In this era of high-tech computer advancements and tremendous programmable computer capabilities, construction cost estimation still remains a knowledge-intensive and experience driven task. High reliance on human expertise, and less

In this era of high-tech computer advancements and tremendous programmable computer capabilities, construction cost estimation still remains a knowledge-intensive and experience driven task. High reliance on human expertise, and less accuracy in the decision support tools render cost estimation error prone. Arriving at accurate cost estimates is of paramount importance because it forms the basis of most of the financial, design, and executive decisions concerning the project at subsequent stages. As its unique contribution to the body of knowledge, this paper analyzes the deviations and behavior of costs associated with different construction activities involved in commercial office tenant improvement (TI) projects. The aim of this study is to obtain useful micro-level cost information of various construction activities that make up for the total construction cost of projects. Standardization and classification of construction activities have been carried out based on Construction Specifications Institute’s (CSI) MasterFormat® division items. Construction costs from 51 office TI projects completed during 2015 and 2016 are analyzed statistically to understand the trends among various construction activities involved. It was found that the interior finishes activities showed a much higher cost of construction, and a comparatively higher variation than the mechanical, electrical, and plumbing (MEP) trades. The statistical analysis also revealed a huge scope of energy saving measures that could be achieved in such TI projects because of the absence of energy management systems (EMS) found in 66% of the projects.

Contributors

Agent

Created

Date Created
  • 2016

151722-Thumbnail Image.png

Re-sonification of objects, events, and environments

Description

Digital sound synthesis allows the creation of a great variety of sounds. Focusing on interesting or ecologically valid sounds for music, simulation, aesthetics, or other purposes limits the otherwise vast

Digital sound synthesis allows the creation of a great variety of sounds. Focusing on interesting or ecologically valid sounds for music, simulation, aesthetics, or other purposes limits the otherwise vast digital audio palette. Tools for creating such sounds vary from arbitrary methods of altering recordings to precise simulations of vibrating objects. In this work, methods of sound synthesis by re-sonification are considered. Re-sonification, herein, refers to the general process of analyzing, possibly transforming, and resynthesizing or reusing recorded sounds in meaningful ways, to convey information. Applied to soundscapes, re-sonification is presented as a means of conveying activity within an environment. Applied to the sounds of objects, this work examines modeling the perception of objects as well as their physical properties and the ability to simulate interactive events with such objects. To create soundscapes to re-sonify geographic environments, a method of automated soundscape design is presented. Using recorded sounds that are classified based on acoustic, social, semantic, and geographic information, this method produces stochastically generated soundscapes to re-sonify selected geographic areas. Drawing on prior knowledge, local sounds and those deemed similar comprise a locale's soundscape. In the context of re-sonifying events, this work examines processes for modeling and estimating the excitations of sounding objects. These include plucking, striking, rubbing, and any interaction that imparts energy into a system, affecting the resultant sound. A method of estimating a linear system's input, constrained to a signal-subspace, is presented and applied toward improving the estimation of percussive excitations for re-sonification. To work toward robust recording-based modeling and re-sonification of objects, new implementations of banded waveguide (BWG) models are proposed for object modeling and sound synthesis. Previous implementations of BWGs use arbitrary model parameters and may produce a range of simulations that do not match digital waveguide or modal models of the same design. Subject to linear excitations, some models proposed here behave identically to other equivalently designed physical models. Under nonlinear interactions, such as bowing, many of the proposed implementations exhibit improvements in the attack characteristics of synthesized sounds.

Contributors

Agent

Created

Date Created
  • 2013