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Inspired by the Rapidly-exploring Random Tree (RRT) data-structure and algorithm for path planning, we introduce an approach for spanning physical space with a group of simple mobile robots. Emphasizing minimalism and using only InfraRed and contact sensors for communication, our position unaware robots physically embody elements of the tree. Although robots are fundamentally constrained in the spatial operations they may perform, we show that the approach -implemented on physical robots- remains consistent with the original data-structure idea. In particular, we show that a generalized form of Voronoi bias is present in the construction of the tree, and that such trees have an approximate space-filling property. We present an analysis of the physical system via sets of coupled stochastic equations: the first being the rate-equation for the transitions made by the robot controllers, and the second to capture the spatial process describing tree formation. We also introduce a class of fixed edge length RRTs called lRRT and show that lRRT s have similar space-filling properties to that of RRTs. We are able to provide an understanding of the control parameters in terms of a process mixing-time and show the dependence of the Voronoi bias on an interference parameter which grows as O*sqrt(N).

In this thesis, we have setup the measurement systems for photocurrent and electro-absorption (Da) spectroscopy, and have investigated the optical characteristics of semiconductor quantum well structures in the long wavelength regime. The measured samples are of three epi-structures including a p-i-n laser structure of the symmetric multiple quantum wells (SMQWs), a p-i-n laser structure of the asymmetric multiple quantum wells (AMQWs), and n-i-n BRAQWETS structures. The samples are fabricated in mesa type photodiode structures for the measurements. From the Da spectrum of the n-i-n BRAQWETS structures, we observe a blue shift ~ 10nm of Da peak caused by band filling effect at +5V bias. Besides, a red shift ~ 2nm has been obtained at ¡V5V bias caused by the quantum-confined Stark effect. The photocurrent spectrum of the SMQWs shows an e1-hh1 absorption peak at hn=0.813eV (l=1.525mm) which matches the photoluminesce spectrum. The e1-hh1 transition has a red-shift ~ 38nm at ¡V5V bias for the SMQWs. For the AMQWs consisting of 5, 10, 15nm wells, we observe the e1-hh1 absorption peaks at 0.758eV (l=1.64mm), 0.772eV (l=1.6mm) and 0.797eV (l=1.55mm), respectively. As the AMQWs biased at ¡V5V, a red-shift ~ 25nm is obtained for the e1-hh1 transition corresponding to the 15nm-wide wells.

This study investigates sub 200nm half-pitch polymer structures by nanoimprint process. The trench structures were fabricated on quartz glass with various depths and widths by FIB. To investigate the best nanoimprint process on SU-8, we studied various parameters such as: imprinting temperature, imprinting pressure, and temperature for de-molding, etc. ¡@This study had successfully defined 50nm width with different depths on to SU-8 by imprint. ¡@Imprint temperature above Tg 30¢J with constant pressure on continuous impressing and de-mold in room temperature would result in better imprinting results. The filling rate of this nanoimprint technology was measured by atomic force microscopy. ¡@For structures above/near 100nm half-pitch, the filling rate is nearly 100%.

A novel selective-filling technology of photonic crystal fibers (PCFs) employing a simple selective-blocking process using UV gel is demonstrated in this thesis. In this study the liquid-filled PCFs with the filling in inside three layers and whole four layers represent the insertion loss of gel 7.5dB and the photonic band gap (PBG) guiding effect at wavelength 1100nm~1300nm, having potential to be tunable optical filters by filling the liquid crystal. The liquid-filled PCFs without the filling of the most inside 1ayer represent low insertion loss of gel 2dB and the total index reflection (TIR) guiding effect, having potential to be low loss tunable fiber gratings by filling the liquid crystal. The liquid-filled PCFs with the filling in middle a layer represent the elliptical far field pattern and effect of birefringence at wavelength 1600nm.

ITC/USA 2014 Conference Proceedings / The Fiftieth Annual International Telemetering Conference and Technical Exhibition / October 20-23, 2014 / Town and Country Resort & Convention Center, San Diego, CA / In this work we evaluated the performance of different water filling algorithms. We have selected four power allocation algorithms: Conventional water-filling (CWF), Constant power water-filling, Inverse Water-filling (IWF), and Adaptive Iterative Water-Filling (AIWF) algorithms. Capacity is the performance metric we used to compare the above algorithms by taking the optimality of transmission power allocation to each sub-channel into account. The power allocation can be calculated with a reference of the water level value that has different approaches for different algorithms. The water level can either be fixed once it is found, or it may be adaptive or different for different sub-channels. Hence, the results show that the adaptive iterative water filling (AIWF) algorithm has a better effect on the performance of MIMO-OFDM system by allocating power adaptively.

Over the last three decades, mine backfilling has progressively integrated into underground mining operations. The high stresses associated with mining at depth in the Canadian Shield, also requires innovative approaches to mine backfilling to withstand the loading both during and after mining operations. Not only new or modified minefill systems are required, but also new techniques are needed to increase the speed of the mining cycle for optimizing the mining operation. Three major purposes of mine backfill are known as (1) providing safe working condition, (2) maximizing ore recovery and (3) improving underground stability. Therefore, mine backfill has contributed greatly to the economics and environmental aspects of mining industry. / In order to improve the mechanical behaviour of fill, cementitious materials are used. These cementitious materials are expensive. As a result the consumption of these cementitious materials has to be optimized and minimized in a way that the required strength is met. The objective of this research is to investigate a new type of backfill, which is known as gelfill. Gelfill binders usually consist of alkali activators such as sodium silicate and the other cementitious materials. Sodium silicate has been used in waste treatment and activation of artificial pozzolans such as blast furnace slag and fly ash. / The work presented in this thesis is to evaluate the use of sodium silicate in gelfill. Consequently, the influence of mixing time, mixing sequence and curing time are studied on gelfill and silica sand hydraulic backfill. Various tests including unconfined and confined compressive strength were conducted in order to investigate the mechanical behaviour of samples. By conducting mercury intrusion porosimetery (MIP) and scanning electron microscopy (SEM), microstructure and mineralogical properties of specimens were studied. / The result of this thesis demonstrates that gelfill compared with silica sand hydraulic backfill has better mechanical properties. In addition, other variables, including: mixing time and sequence, have a significant effect on gelfill.

Thesis (M.S.)--University of Michigan, Ann Arbor, 1974. / Typescript (photocopy). Includes bibliographical references (leaves 30-31). Also issued in print.

Thesis (M.S.)--University of Michigan, 1986.

Thesis (M.S.)--University of Michigan, 1986.