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<p>We consider the problem of power allocation for the single-cell multiple-input single- output (MISO) downlink in a time division duplex (TDD) system. In such systems, the base station (BS) acquires information about the channel state during the training component of the uplink phase. The resulting estimation errors are modeled prob- abilistically, and the receivers specify quality-of-service (QoS) constraints in terms of a target signal-to-interference-and-noise ratio that is to be achieved with a given outage probability. For a fixed beamforming structure, we seek a power allocation that minimizes the transmission power required to satisfy the users’ QoS requests.</p> <p>The proposed approach to that problem begins with the observation that for TDD systems the channel estimation error at the base station can be modeled as being additive and Gaussian. Under that model, we obtain a precise deterministic characterization of the outage probability, and mildly conservative approximations thereof. Although the resulting deterministic optimization problems are not convex, we have been able to obtain good solutions using straightforward coordinate update algorithms. In fact, these solutions provide significantly better performance than the existing approaches, which are based on convex restrictions, because the proposed approximations are less conservative. By developing some approximations of the precise deterministic characterization of the outage probability, we develop algorithms that have good performance and much lower computational cost.</p> / Master of Applied Science (MASc)

Running injuries have been linked to poor lower extremity dynamic alignment, increased whole body and joint loading, and insufficient modulation of stiffness throughout stance phase. Upper body muscle activity and movement have a relationship to lower body dynamics; however, the literature has largely neglected their role during running. To date, biomechanical gait analysis has primarily focused on lower extremity mechanics and muscle activation patterns with no studies investigating the role of functional muscle synergies on stability and loading during running. Therefore, the primary objective of this project is to determine the role of the Back Functional Line (BFL), via measure of latissimus dorsi (LD), gluteus maximus (GM), and vastus lateralis (VL) muscle activity, during running and to determine their influence on lower extremity kinematics and kinematic predictors of loading that are linked to running-related injuries (RRI). We used conditions of arm swing constraint to manipulate the action of the LD and investigate the response in GM and VL muscles. Our main variables of interest include: 1) BFL muscle activity, specifically mean and peak amplitude, onset, and co-activation of the LD and GM 2) frontal plane lower extremity kinematics, and 3) kinematic predictors of kinetics, specifically foot inclination angle at initial contact and vertical COM displacement. Twenty healthy recreational runners (10 M; 10 F) participated in this study. Male runners tended to be slighter older with a higher weekly running mileage and longer running history. All participants were between the ages of 18 and 55 years old and consistently ran at least once per week. Participants ran under three arm conditions - free arm swing, unilateral arm swing constraint, and bilateral arm swing constraint. During the running trials, surface EMG and lower extremity kinematics were collected over the gait cycle. We operationally defined the primary BFL as the muscle synergy composed of the non-dominant upper extremity (i.e., constrained side during unilateral condition) LD muscle, the dominant GM muscle, and the dominant VL muscle. The secondary BFL was defined as the dominant upper extremity (i.e., unconstrained during unilateral condition) LD muscle, the non-dominant GM muscle, and the non-dominant VL muscle. Primary and secondary BFL muscle synergy activity were analyzed during two specific phases of gait - the pre-activation (PA) phase and the loading response (LR) phase. In support of the hypothesis, the primary BFL LD mean amplitude decreased during both the PA and LR phases of gait. GM and VL muscle mean amplitude demonstrated a varied response. During the PA phase, both the GM and VL muscles increased during the unilateral condition and decreased during the bilateral condition. During LR phase, GM and VL muscles increased during both arm swing constraint conditions. The highest increase in amplitude was seen during the unilateral condition. Peak amplitudes for each muscle did not change dramatically across conditions for either the PA or LR phases of gait. Secondary BFL LD and GM mean and peak amplitude increased during both the PA and LR phases of gait, with changes during the LR phase reaching significance for both muscles. Secondary BFL VL also increased in mean and peak amplitude during the bilateral constraint condition. GM and VL mean and peak muscle amplitude were significantly correlated during the LR phase, but not for the PA phase. This indicates that the lower extremity muscles of the BFL (GM and VL) may not be preparing for impact similarly but are adjusting muscle activity in a similar fashion as the lower limb is loaded. The increase in muscle amplitude for secondary BFL muscles, particularly during the LR phase of gait, may have resulted from a difference between lower limb strength or lower extremity single leg stability. Onset of muscle activity during loading response did not significantly differ across conditions for the LD, GM, or VL muscles, however, analysis of co-activation demonstrated that LD and GM were in-phase throughout the gait cycle. This suggests that this portion of the BFL may be acting together to stabilize the lumbopelvic-hip complex (LPHC) during running. LD and GM appeared to be co-activated throughout the gait cycle regardless of arm swing variation. Instability, either from asymmetrical movement patterns or poor single leg stability may contribute to the activation of the BFL muscle synergy. GM increased during the unilateral arm swing constraint during both phase and for both BFL synergies, indicating that asymmetrical movement patterns may induce a potential instability or an unstable state requiring the need for greater stability around the LPHC. Knee frontal plane kinematics changed significantly across conditions. Knee abduction angle showed the greatest increase during the unilateral arm swing constraint condition suggesting that asymmetrical movement patterns effect lower extremity mechanics more so than symmetrical patterns (i.e., bilateral arm swing restriction or free arm swing). Hip adduction and contralateral pelvic drop angles did not differ significantly across conditions. Our study did not find a significant relationship between BFL muscle activity and knee abduction angles. Participants demonstrated larger knee abduction angles on their non-dominant limb at midstance. The corresponding (secondary) BFL LD and GM demonstrated a significant increase during the LR phase. This may indicate that BFL muscle activity is engaged when the need for lower limb stability is greater, either due to poor single leg dynamic control or abnormal frontal plane mechanics. Kinematic predictors of joint and whole-body loading differed across conditions. Vertical COM displacement was significantly decreased during the bilateral arm swing constraint condition. Foot inclination angle at initial contact did not significantly change with arm swing constraint. Differences were found between right and left lower extremity foot strikes (i.e., foot inclination angle) across all conditions; the non-dominant limb demonstrated greater plantarflexion during initial contact. Knee flexion angle at initial contact and peak knee flexion during stance did not demonstrate a significant change. Muscle activity was not significantly correlated to kinematic predictors. Spatiotemporal measures altered with arm swing suppression. Stride length decreased and step rate increased significantly. Taken together, these results suggest that runners alter spatiotemporal measures more so than sagittal plane kinematics when adjusting to arm swing suppression. The role of the BFL muscle synergy during running remains unclear. Asymmetrical movement patterns and arm swing restriction appear to influence BFL muscle activity and lower extremity kinematics. Single leg stability, particularly during the LR phase, may alter BFL muscle activity due to the need for increased stabilization of the loaded limb and the LPHC. Future research is needed to determine how these variables impact BFL muscle activation and whether injured runners respond differently to arm swing constraint during running. / Physical Therapy

The field of immuno-oncology has made tremendous advances in the treatment of cancer. Adoptive cellular transfer (ACT) of tumor-specific T cells and oncolytic viruses (OVs) are powerful anti-tumor agents, but each modality faces significant challenges. Despite the promise of ACT against hematological malignancies, success has been limited in solid tumors. OVs preferentially lyse tumor cells, but have difficulty overcoming antiviral host factors when delivered systemically – therapeutic doses must therefore be quite high to achieve tumor delivery. One means of overcoming viral neutralization is by loading OV onto cellular carriers prior to treatment. Since engineered T cells and OVs both possess anticancer activity, and since viruses naturally associate with nearby circulating immune cells, employing T cells engineered with a T cell antigen coupler (TAC) receptor as viral carriers may offer an ideal combination. Our studies indicated that loading oncolytic maraba virus (MRB) onto T cells – engineered with a TAC receptor targeting HER2 – had no impact on the functionality or receptor expression of these T cells. OV loaded on the surface of these TAC-T cells enabled killing of a variety of tumor targets that may be otherwise resistant to TAC-T cell therapy. Efficacy remains to be elucidated in vivo using xenograft murine models due to the lack of a protective antiviral immune response, which ultimately resulted in encephalopathy. These observed toxicities were likely model-specific, as MRB has shown to be highly attenuated in healthy tissues of wild type models. While conceptually attractive, using TAC-T cells as viral carriers to deliver a multi-pronged, one-pot antitumor therapy directly to the site of the tumor requires further evaluation before considering human studies. / Thesis / Master of Science (MSc)

Four different thermoviscoplastic relations, namely, the Litonski-Batra, the Johnson-Cook, the Bodner-Partom and the power law are used to model the thermoviscoplastic response of a material. Each one of these relations accounts for strain hardening, strain-rate hardening and thermal softening of the material. The material parameters in these relations are found by solving an initial-boundary-value problem corresponding to simple shearing deformations so that the computed effective stress vs. the effective plastic strain curves match closely with the experimental data of Marchand and Duffy who tested thin-walled HY-100 steel tubes in torsion. These four viscoplastic relations are used to analyze dynamic thermomechanical deformations of a prenotched plate impacted on the notched side by a cylindrical projectile made of the same material as the plate. The impact loading on the contact surface is simulated by prescribing the time history of the normal component of velocity and null tangential tractions. A plane strain state of deformation is assumed to prevail in the plate and its deformations are studied for different values of the impact speed. The in-house developed finite element code employs constant strain triangular elements, one point integration rule, and a lumped mass matrix. The Lagrangian description of motion is used to describe deformations of the plate. The coupled nonlinear partial differential equations are first reduced to coupled nonlinear ordinary differential equations (ODEs) by using the Galerkin approximation. The ODEs are integrated by using the stiff solver, LSODE, which adaptively adjusts the time step size and computes the solution within the prescribed accuracy. Results computed with the four constitutive relations are found to be qualitatively similar to each other and the general trends agree with the experimental observations in the sense that at low speed of impact, a brittle failure ensues at a point on the upper surface of the notch tip. However, at high impact speeds, a ductile failure in the form of a shear band initiates first from a point on the lower surface of the notch tip. The predicted speed at which the failure mode transitions from brittle to ductile is different for the four viscoplastic relations. Results have been computed using the Bodner-Partom law to study the effects of the notch tip radius and the presence of a circular hole ahead of the notch-tip. For sharp elliptic notch tips, it is found that there is no failure transition speed and the ductile failure always preceeded the brittle failure for the range of the impact speeds studied. For the hole located on the axis of the circular notch tip, the brittle failure always preceeded the ductile failure and it initiated at a point on the lower surface of the circular hole. / Ph. D.

The design of metal building roof and wall systems under uplift and suction wind loading is complicated because the laterally unbraced purlin and girt's free flange is compressed, and the cross-section rotates due to the shear flow. The objective of this thesis is to introduce a Direct Strength Method (DSM) prediction approach for simple span purlins and girts with one flange through-fastened under uplift or suction loading. This prediction method is also applicable for the case when rigid board insulation is placed between the metal panel and through-fastened flange. The prediction method is validated with a database of 62 simple span tests. To evaluate the prediction for the case when rigid board is used, 50 full-scale tests with rigid board insulation are conducted by the author of this thesis. In the experimental study panel failure, connection failure and member (purlin and girt) failure are observed, and they all limit the system's capacity. Another important contribution of this thesis is that it builds the foundation for future study of a general, mechanics-based limit state design approach for metal building roof and wall systems that can accommodate uplift and gravity loads, simple and continuous spans, and through-fastened and standing seam roofs. / Ph. D.

The research in this dissertation addresses reduced rank adaptive signal processing, with specific emphasis on the multistage Wiener filter (MWF). The MWF is a generalization of the classical Wiener filter that performs a stage-by-stage decomposition based on orthogonal projections. Truncation of this decomposition produces a reduced rank filter with many benefits, for example, improved performance. This dissertation extends knowledge of the MWF in four areas. The first area is rank and sample support compression. This dissertation examines, under a wide variety of conditions, the size of the adaptive subspace required by the MWF (i.e., the rank) as well as the required number of training samples. Comparisons are made with other algorithms such as the eigenvector-based principal components algorithm. The second area investigated in this dissertation concerns "soft stops", i.e., the insertion of diagonal loading into the MWF. Several methods for inserting loading into the MWF are described, as well as methods for choosing the amount of loading. The next area investigated is MWF rank selection. The MWF will outperform the classical Wiener filter when the rank is properly chosen. This dissertation presents six approaches for selecting MWF rank. The algorithms are compared to one another and an overall design space taxonomy is presented. Finally, as digital modelling capabilities become more sophisticated there is emerging interest in augmenting adaptive processing algorithms to incorporate prior knowledge. This dissertation presents two methods for augmenting the MWF, one based on linear constraints and a second based on non-zero weight vector initialization. Both approaches are evaluated under ideal and perturbed conditions. Together the research described in this dissertation increases the utility and robustness of the multistage Wiener filter. The analysis is presented in the context of adaptive array processing, both spatial array processing and space-time adaptive processing for airborne radar. The results, however, are applicable across the entire spectrum of adaptive signal processing applications. / Ph. D.

Foot posture is an important characteristic that can affect kinematics, plantar loading, and injury risk. Arch height is one common aspect of foot posture, and it is estimated that about 60% of the population has normal arches while 40% of the population is either pes planus or pes cavus. It is important to be able to accurately and reliably assess foot posture characteristics in order to propose interventions that could prevent injuries due to abnormal foot alignment. However, despite multiple classification metrics, many of the devices that are commonly used for foot posture measurements are not economically feasible for smaller clinics or research labs. Therefore, the first purpose of this study was to develop an affordable device to measure different foot posture characteristics. The Foot Posture Measurement System was developed and can measure total foot length, truncated foot length, foot width, dorsum height, and navicular height. This system was shown to have good to excellent validity (ICC = 0.908-0.994) and repeatability (ICC = 0.867-0.996) when compared to a 3D scanner. This device was then used in the second portion of this study, which evaluated the effects of ankle braces on plantar loading patterns in individuals with different foot postures. Contact area, peak force, force-time integral, and center of pressure were evaluated during a walk, run, and cut while the participant was unbraced, wearing a lace-up stabilizer brace, and wearing a semi-rigid brace. It was demonstrated that arch height did affect the maximum plantar forces during all tasks (p=0.001-0.047), as hypothesized based on previous studies. Additionally, this study found that ankle braces affected contact area (p=0.001-0.0014), maximum force (p<0.001 – p=0.043), and force-time integral (p<0.001 – p=0.015) during the walk, run, and cut. This is a novel finding and points to the potential for an impact of ankle braces on plantar loading during athletic activities, independent of foot type. / Master of Science / Foot posture is an important characteristic that can affect daily life and contribute to the risk of injury. Arch height is one common aspect of foot posture, and it is estimated that about 60% of the population has normal arches while 40% of the population is either high arched or low arched/flat footed. It is important to be able to accurately and reliably assess foot posture characteristics in order to propose interventions that could prevent injuries due to abnormal foot alignment. However, despite multiple classification metrics, many of the devices that are commonly used for foot posture measurements are not economically feasible for smaller clinics or research labs. Therefore, the first purpose of this study was to develop an affordable device to measure different foot posture characteristics. The Foot Posture Measurement System was developed and can measure five different length, width, and height characteristics of the foot. This system was shown to be valid when compared to a 3D scanner and repeatable between days. This device was then used in the second portion of this study, which evaluated the effects of ankle braces on individuals with different foot postures. Four different force and pressure variables were examined within the foot during a walk, run, and cut while the participant was unbraced, wearing a lace-up stabilizer brace, and wearing a semi-rigid brace. It was shown that arch height did alter plantar loading measures during all tasks, as hypothesized based on previous studies. Additionally, this study found that ankle braces affected all variables during the walk, run, and cut. This is a novel finding and points to the potential for an impact of ankle braces on plantar loading during athletic activities, independent of foot type.

The continual increase in anterior cruciate ligament (ACL) injuries in sports makes it the most common ligament injury and leads the athlete down a difficult road with reconstruction surgery (ACLR) and months of rehabilitation. Specifically, females are at a greater risk of both primary and secondary ACL injuries compared to males. The purpose of this research was to understand the differences in movement and loading variability between ACLR and healthy athletes during unilateral and bilateral landings while utilizing limb symmetry to understand between group differences. It was hypothesized that females with an ACLR would have greater variability compared to males with an ACLR and healthy female athletes. 40 ACLR and 67 healthy athletes were asked to complete seven stop jumps and 25 ACLR and 30 healthy athletes completed seven single hop trials to assess intra-subject variability. The stop jump task utilized embedded force plates and motion capture technology while the single hop task used loadsol® in-shoe force sensors. The measures studied with the stop jump included posterior and vertical ground reaction force (GRF), knee/hip abduction/adduction angles, and loading rate. The single hop measures included peak force, loading rate, and impulse. To assess variability and limb symmetry, coefficient of variation (CV) and the limb symmetry index (LSI) were calculated for each of outcome measure. A linear mixed effects model was completed in JMP (SAS Institute Inc., Cary, NC) with p<0.05 to see the effects of group, sex, and limb. During the stop jump task, the ACLR athletes showed higher variability for both posterior GRF (p<0.001), posterior GRF LSI (p<0.001), and loading rate (p=0.027) compared to controls. Females with an ACLR had higher variability in vertical GRF (p<0.001) and vertical GRF symmetry (p=0.029) compared to HC females. Additionally, females with an ACLR had higher variability in the vertical GRF (p=0.033) when compared to males with an ACLR. Knee abduction angle (p=0.024) showed males with an ACLR to have higher variability compared to females with an ACLR. For the single hop task, there was a significant difference between sex for loading rate (p<0.001), loading rate LSI (p=0.004), impulse (p=0.006), and impulse LSI (p=0.001) with males producing a higher mean CV compared to females in all measures regardless of group. Overall, these results support the hypothesis that group and sex differences exist and that females with an ACLR will have higher variability and asymmetrical movements than male ACLR patients and healthy females during bilateral landings, which could lead to increased injury risk. In unilateral landings, the results suggest that females are landing with less variability compared to males. With increased variability on the surgical limb of an athlete with an ACLR, it is likely that the athlete will have a more successful return to sport as they can react and adapt to changes in landing during sports. Future work should report reinjury rates to investigate the potential role of movement variability in injury risk and potentially determine variability thresholds for injury risk. The evaluation of bilateral and unilateral landings revealed the need to include both landing tasks in return to sport testing as well as a limb symmetry metric to understand an athlete's functional readiness to react to changing conditions during sports related movement. / Master of Science / Anterior cruciate ligament (ACL) injuries continue to rise in all sports and result in athletes having to undergo reconstruction surgery (ACLR) and months of rehabilitation if they want to compete at a high level again. Specifically, females have a greater risk of suffering both a primary and secondary ACL injury compared to males. Movement differences have been previously researched in hopes of decreasing injury risk. Variability, or the differences between one trial to the next, is a way to visualize the athlete's ability to adapt following injury. The ideal level of adaptability is still unclear as too much variability can be seen as unstable while too little can be seen as unforgiving. The purpose of this project was to better understand movement and loading variability between ACLR and healthy athletes during one legged (unilateral) and two legged (bilateral) landings. Differences between limbs were analyzed to understand whether one leg was favored over the other. Every participant completed seven stop jump trials which required them to run forward, jump off one leg and landing with two legs followed by a maximum vertical jump; another different group completed a series of seven single leg hop tasks during which they started on one-leg and jumped forward as far as they could while maintaining their balance. The measures studied with the stop jump included peak vertical and posterior force, frontal plane knee and hip angles, and loading rate. The single hop measures included peak force, loading rate, and impulse. The loading rate is defined as the ratio of peak force divided by the time it takes the athlete to reach peak force following initial contact. Impulse is the area under the force time curve and provides insight into the athlete's ability to dissipate load. The force data from each trial performed were collected using force plate technology and loadsol® shoe inserts. Variability was calculated using the coefficient of variation (CV) which is the ratio between the standard deviation and the mean value across the trails. The limb symmetry index (LSI) was calculated as the ratio between the surgical/non-dominant and the non-surgical/dominant limbs. During a stop jump, female patients with an ACLR showed greater variability in peak force and force LSI revealing asymmetric landing compared to healthy females. Additionally, females with an ACLR had greater variability compared to males with an ACLR in peak force. The ACLR group had greater variability in posterior force, posterior force symmetry, and loading rate compared to the athletes in the healthy group. During a single hop, males had higher greater variability in loading rate, loading rate limb difference, impulse, and impulse limb difference compared to females. These results suggest that all females have a more unstable and asymmetrical landing compared to all males during bilateral landing. However, during a unilateral landing, females had a less forgiving landing compared to males, which could also indicate an increased injury risk. Future work should investigate reinjury rates to determine whether variability impacts injury risk and if differences in injury risk between males and females are associated with differences in variability.

A two-dimensional, nonlinear dynamic analysis is conducted on a moored breakwater configuration to investigate snap loads in mooring lines. Breakwaters are structures used to attenuate or eliminate waves and protect shorelines, harbors, and other natural and man-made marine structures from wave damage. The breakwater in this investigation is modeled both as a point mass and as a rigid body. Both models are subjected to free undamped motions and forced undamped wave motion. Energy is dissipated through the use of a coefficient of restitution applied when a mooring line becomes taut (i.e., reaches its natural length). The mooring line is modeled as an inextensible cable with no axial or bending resistance when slack. Snap loading arises when a mooring line transitions suddenly from a slack condition to a taut condition. The analysis was conducted on a breakwater configured upside down and hanging by two mooring lines. The length of the mooring lines, coefficient of restitution, size and shape of the breakwater, initial position of the breakwater, amplitude of wave forcing, ratio of vertical to horizontal forcing, and frequency of forcing were all varied in the analysis. The results show that the rotations of the rigid body and the wave forcing have a significant role in the analysis, indicating that a rigid-body model for a moored breakwater under wave forcing is the more accurate model. / Master of Science