This dissertation introduces a new method, Pratt's measure matrix, for interpreting multidimensional oblique factor models in both exploratory and confirmatory contexts. Overall, my thesis, supported by empirical evidence, refutes the currently recommended and practiced methods for understanding an oblique factor model; that is, interpreting the pattern matrix or structure matrix alone or juxtaposing both without integrating the information. Chapter Two reviews the complexities of interpreting a multidimensional factor solution due to factor correlation (i.e., obliquity). Three major complexities highlighted are (1) the inconsistency between the pattern and structure coefficients, (2) the distortion of additive properties, and (3) the inappropriateness of the traditional cut-off rules as being "meaningful". Chapter Three provides the theoretical rationale for adapting Pratt's importance measures from their use in multiple regression to that of factor analysis. The new method is demonstrated and tested with both continuous and categorical data in exploratory factor analysis. The results show that Pratt's measures are applicable to factor analysis and are able to resolve three interpretational complexities arising from factor obliquity. In the context of confirmatory factor analysis, Chapter Four warns researchers that a structure coefficient could be entirely spurious due to factor obliquity as well as zero constraint on its corresponding pattern coefficient. Interpreting such structure coefficients as Graham et al. (2003) suggested can be problematic. The mathematically more justified method is to transform the pattern and structure coefficients into Pratt's measures. The last chapter describes eight novel contributions in this dissertation. The new method is the first attempt ever at ordering the importance of latent variables for multivariate data. It is also the first attempt at demonstrating and explicating the existence, mechanism, and implications of the suppression effect in factor analyses. Specifically, the new method resolves the three interpretational problems due to factor obliquity, assists in identifying a better-fitting exploratory factor model, proves that a structure coefficient in a confirmatory factor analysis with a zero pattern constraint is entirely spurious, avoids the debate over the choice of oblique and orthogonal factor rotation, and last but not least, provides a tool for consolidating the role off actors as the underlying causes. / Education, Faculty of / Educational and Counselling Psychology, and Special Education (ECPS), Department of / Graduate

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Background: The abdominal muscles are vital in providing core stability for proper function in most activities. There is a correlation between side asymmetry of theses muscles and dysfunction. Thus, the purpose of this study was to evaluate and compare trunk muscle morphology and trunk rotational strength between sprinters, a symmetrical sport and sprint hurdlers, an asymmetrical sport. Methods: Twenty-one trained collegiate sprinters and sprint hurdlers were recruited for the study (12 M, 9 F), average age (years) 20.2   1.5, height (cm) 176.9   9.1, and weight (kg) 70.6   9.8. Using real-time ultrasound, panoramic images of the internal oblique (IO) and external oblique (EO) were obtained at rest and contracted in a seated position for both right and left sides of the trunk. Results: Average trunk rotation strength to the right was greater among all participants, p < 0.001. The IO had greater thickness changes than EO for all participants. The IO side asymmetry was significantly different between groups p < 0.01. Conclusion: Sprinters, although involved in a seemingly symmetrical sport, exhibit asymmetrical trunk morphology and rotational strength, while hurdlers, involved in a unilaterally demanding sport, exhibit the expected asymmetry in muscle morphology and trunk rotational strength.

In a rectangular cross-section wind tunnel a separated oblique shock reflection is set to interact with the turbulent boundary layer (oblique SBLI) both on the bottom wall and in the corner formed by the intersection of the floor with the side-walls. In such a scenario, shock-induced separation is often seen in each of the streamwise corners, resulting in a highly three-dimensional flow field in the near-wall region. To examine how the corner separations can affect the `quasi-two-dimensional' main interaction and by what mechanism this is achieved, an experimental investigation has been conducted. This examines how modifications to the corner separation influence an oblique shock reflection. The nature of the flow field is studied using flow visualisation, Pressure Sensitive Paint and Laser Doppler Anemometry. A nominal freestream Mach number of 2.5 is used for all experiments with a unit Reynolds number of $40\times10^6$m$^{-1}$, and the shock-generator angle is set to $8^\circ$. The flow conditions are chosen to result in substantial separations both in the corners and along the centreline for the baseline case, which is thought to be a good starting point for this study. The results show that the size and shape of central separation vary considerably when the onset and magnitude of corner separation change. The primary mechanism coupling these separated regions appears to be the generation of compression waves and expansion fans as a result of the displacement effect of the corner separation. The presence and strength of the expansion waves have been overlooked in previous studies. This is shown to modify the three-dimensional shock-structure and alter the adverse pressure gradient experienced by the tunnel floor boundary layer. It is suggested that a typical oblique SBLI in rectangular channels features several zones depending on the relative position of the corner waves and the main interaction domain. In particular, it has been shown that the position of the corner `shock' crossing point, found by approximating the corner compression waves by a straight line, is a critical factor determining the main separation size and shape. Thus, corner effects can substantially modify the central separation. This can cause significant growth or contraction of the separation length measured along the symmetry line from the nominally two-dimensional baseline value, giving a fivefold increase from the smallest to the largest observed value. Moreover, the shape and flow topology of the centreline separation bubble is also considerably changed by varying corner effects.

Surge Free Added Resistance testing in variable head wave conditions were completed for a container ship model. The added resistance experiments include calm water, head wave, and oblique wave cases with a focus on establishing a validation benchmark for CFD codes computing the added resistance and motions of the ship model during maneuvering. The ship used is a 1/85.19 scale KRISO Container Ship, KCS, model with a length of 2.70 m. Tests were performed at the IIHR wave basin. The 20 x 40 x 4.5 m wave basin is equipped with 6 inline plunger type wave makers and a 3 degrees of freedom carriage. A 4 degrees of freedom, surge, heave, roll, and pitch free mount with a mass spring damper system was used to tow the model. Calm water tests were performed for 13 Froude numbers between 0.0867 and 0.2817. The resistance coefficients, sinkage, and trim were found for each test. The calm water results were obtained and compared to results from towing tank facilities, with traditional mounts, to estimate facility biases at the IIHR wave basin. The results show that the size difference of the IIHR model and surge free motion create magnitude differences between facilities. Head and oblique wave tests were performed at Froude number 0.26 and wave height to wavelength ratio, H/λ, of 0.0167. For all wave tests, time histories of wave amplitude, resistance, and 4 DOF were measured. Fourier analysis was completed for all time histories of waves, forces, and motions and the 0th, 1st, and 2nd harmonic amplitudes and phases are presented. All head wave results are compared to other facilities data taken in a towing tank with a traditional mount. The data from all wave heading data was analyzed with a focus on the trends with incremented wave encounter angle. Most harmonic amplitudes show good agreement between all facilities, but removal of the small model used by IIHR shows even better agreement between facilities. The oblique wave heading data shows good agreement with the only other experimental oblique wave added resistance testing. Complete uncertainty analysis was completed for select cases for calm water, head wave, and oblique wave conditions. The uncertainty showed accurate data form most wavelength settings.

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国立情報学研究所で電子化したコンテンツを使用している。

Bakgrund: Vastus medialis kan delas in i två olika komponenter beroende på fiberriktning. Den nedre delen vastus medialis oblique (VMO) har sitt ursprung från adductor magnus och drar patella medialt medans vastus lateralis (VL) drar patella lateralt. En obalans mellan VMO och VL kan leda till avvikelse i patellas position och rörelse vilket är en orsak till patellofemoralt smärtsyndrom (PFSS). En aktivering av adductor magnus sätter VMO på sträck vilket leder till bättre kontraktionskraft av VMO. Knäböj utförda på instabilt underlag har visat på en ökad aktivering av VMO. Syfte: Syftet var att göra en initial pilotstudie för att undersöka skillnaden i muskelaktivering av VMO vid knäböj på stabilt underlag jämfört med en knäböj på instabilt underlag med samtidig aktiv höftadduktion. Metoden: Friska unga män utförde knäböj på instabilt underlag med aktiv höftadduktion respektive knäböj på stabilt underlag. Utfallsvariablar var EMG-amplitud på VMO och VL samt kvoten VMO:VL. Resultatet: Samtliga fem deltagare fick minskad muskelaktivering av VMO i övningen knäböj på instabilt underlag med aktiv höftadduktion jämfört med knäböj på stabilt underlag. Två av fem deltagare fick högre VMO:VL-kvot i övningen knäböj på instabilt underlag med aktiv höftadduktion. Konklusion: Resultatet tyder på att en knäböj på instabilt underlag med samtidig aktiv höftadduktion jämfört med en knäböj på stabilt underlag inte ger en ökad aktivering av VMO eller en högre VMO:VL-kvot hos friska unga män. Utifrån resultaten och tidigare studier inom området behövs det mer studier med vissa metodologiska förändringar för att en given slutsats ska kunna dras.

In this paper the popup height of rising buoyant spheres is studied over a range of distinct release depths along with the accompanying velocities and accelerations near the free surface. In the past, regimes of motion due to vortex induced vibrations have been classified based on trajectories below the free surface. This study focuses on the popup height, velocity and acceleration at free surface exit, and vortex shedding in order to further define regimes of motion experienced by a rising buoyant sphere. Varying the release depth below the free surface reveals varying exit angles, velocities, accelerations, and popup heights at surface exit. Vortex shedding prior to free surface exit causes decelerations contributing to the variation in exit velocities and resulting popup heights. Using high-speed imaging and particle image velocimetry, we examine the trajectories, accelerations, velocities and vortex shedding events for spheres of different mass ratios over a range of Reynolds number (2e4 >Re> 6e5). At lower Re, spheres released from shallow release depths result in greater accelerations and velocities at free surface exit along with greater popup heights compared to releases from deeper depths. After reaching a depth which results in a minimum popup height, further increasing the release depth reveals an increase in popup height demonstrating an oscillatory pattern due to the sphere being released from vortex forces after shedding. This pattern is repeated as the popup height again decreases with greater release depths. For spheres of greater Re, popup height increases linearly with release depth, demonstrating continued accelerations at free surface exit.

A method was developed to assist with the understanding of a unique configuration and investigate some of its stability and control attributes. Oblique wing aircraft concepts are a design option that is well understood, but has yet to be used in a production aircraft. Risk involved in choosing such a design can be averted through additional knowledge early in the concept evaluation phase. Analysis tools commonly used in early conceptual level analysis were evaluated for applicability to a non-standard aircraft design such as an oblique flying wing. Many tools used in early analyses make assumptions that are incompatible with the slewed wing configuration of the vehicle. Using a simplified set of tools, an investigation of a unique configuration was done as well as showing that the aircraft could be trimmed at given conditions. Wave drag was investigated to determine benefits for an oblique flying wing. This form of drag was reduced by the distribution of volume afforded by the slewing of the aircraft's wing. Once a reasonable concept was developed, aerodynamic conditions were investigated for static stability of the aircraft. Longitudinal and lateral trim were established simultaneously due to its asymmetric nature. / Master of Science