This dissertation describes the development and results of a physiological rigid body forward solution mathematical model that can be used to predict normal knee and total knee arthroplasty (TKA) kinematics and kinetics. The simulated activities include active extension and weight-bearing deep knee bend. The model includes both the patellofemoral and tibiofemoral joints. Geometry of the normal or implanted knee is represented by multivariate polynomials and modeled by constraining the velocity of lateral and medial tibiofemoral and patellofemoral contact points in a direction normal to the geometry surface. Center of mass, ligament and muscle attachment points and normal knee geometry were found using computer aided design (CAD) models built from computer tomography (CT) scans of a single subject. Quadriceps forces were the input for this model and were adjusted using a unique controller to control the rate of flexion, embedded with a controller which stabilizes the patellofemoral joint. The model was developed first using normal knee parameters. Once the normal knee model was validated, different total knee arthroplasty (TKA) designs were virtually implanted. The model was validated using in vivo data obtained through fluoroscopic analysis. In vivo data of the extension and deep knee bend activities from five non-implanted knees were used to validate the normal model kinematics. In vivo kinematic and kinetic data from a telemetric TKA with a tibia component instrumented with strain gauges was used to validate the kinematic and kinetic results of the model implanted with the TKA geometry. The tibiofemoral contact movement matched the trend seen in the in vivo data from the one patient available with this implant. The maximum axial tibiofemoral force calculated with the model was in 3.1% error with the maximum force seen in the in vivo data, and the trend of the contact forces matched well. Several other TKA designs were virtually implanted and analyzed to determine kinematics and bearing surface kinetics. The comparison between the model results and those previously assessed under in vivo conditions validates the effectiveness of the model and proves that it can be used to predict the in vivo kinematic and kinetic behavior of a TKA.

This research presents a procedure for interactive segmentation and automatic tracking of moving objects in a video sequence. The user outlines the region of interest (ROI) in the initial frame; the procedure builds a refined mask of the dominant object within the ROI. The refined mask is used to model a spline template of the object to be tracked. The tracking algorithm then employs a motion model to track the template through a sequence of frames and gathers the 3D affine motion parameters of the object from each frame. The extracted template is compared with a previously stored library of 3D shapes to determine the closest 3D object. If the extracted template is completely new, it is used to model a new 3D object which is added to the library. To recreate the motion, the motion parameters are applied to the 3D object in a virtual environment. The procedure described here can be applied to industrial problems such as traffic management and material flow congestion analysis.

The purpose of this report is to cover the procedure of creating and explaining how to use a tool kit that allows the haptic Application Programming Interface (API) H3D from SenseGraphics to be used in conjunction with an advanced physics simulator from Meqon. Both haptic applications and physics engines have developed rapidly the last couple of years but they are rarely used together. If such a connection would be created it would be possible to interact with complex environments in a new way and a variety of haptic applications can be produced. The physics engine from Meqon has gained recognition for its abilities to produce realistic results due to efficient implementation of collision detection system, friction models and collision handling, among other things. H3D is a completely open source API that is based on standards such as OpenGL and X3D. H3D consists of a data base containing nodes, an XML parser to extract a scene graph from the data base and functionality to produce a graphic and haptic interface. The tool kit produced in this thesis is an extension to H3D. A fundamental function of the tool kit is to communicate with the Meqon system and still be a part of the H3D structure. The Meqon system has a modular structure where each module has its own abilities. Only the rigid body module is utilised by the tool kit, which however is the most important module. It is possible to define global settings of the engine and rigid body module, add rigid bodies with several elements and insert constraints on the motion of the rigid bodies into the engine. All of these operations are done from the X3D file format that H3D uses, thus letting all functionality of the H3D system available.

The following report contains an evaluation of the use of mathematical simulation programs at the company Isaberg Rapid AB. The work includes booth FE and motion simulations where the results are compared with real life test data. The goal of the report is to evaluate the accuracy of simulations which can be performed by engineers as a part of the design process. By using mathematical simulation tools it is possible to find a good design solution early in the development phase and thereby shorten lead time and reduce costs.

Conformational selection is the idea that proteins traverse positions on the conformational space represented by their potential energy landscape, and in particular positions considered as local energy minima. Conformational selection a useful concept in ligand binding studies and in exploring the behavior of protein structures within that energy landscape. Often, research that explores protein function requires the generation of conformational ensembles, or collections of protein conformations from a single structure. We describe a method of conformational ensemble generation that uses joint-constrained rigid-body dynamics (an approach that allows for explicit consideration of rigidity) and the elastic network model (providing structurally derived directional guides for the rigid-body model). We test our model on a selection of unbound proteins and examine the structural validity of the resulting ensembles, as well as the ability of such an approach to generate conformations with structural overlaps close to the ligand-bound versions of the proteins.

Many bridges are damaged by collisions from over-height vehicles resulting in significant impact to the transportation network. To reduce the likelihood of impact from over-height vehicles, steel pedestals have been used as a cost-effective, efficient means to increase bridge clearance heights. However, these steel pedestals installed on more than 50 bridges in Georgia have been designed with no consideration of seismic loads and may behave in a similar fashion to high-type steel bearings. Past earthquakes have revealed the susceptibility of high-type bearings to damage, resulting in the collapse of several bridges. Although Georgia is located in a low-to-moderate region of seismicity, earthquake design loads for steel pedestals should not be ignored. In this study, the potential vulnerabilities of steel pedestals having limited strength and deformation capacity and lack of adequate connection details for anchor bolts is assessed experimentally and analytically. Full-scale reversed cyclic quasi-static experimental tests are conducted on a 40' bridge specimen rehabilitated with 19" and 33" steel pedestals to determine the modes of deformation and mechanisms that can lead to modes of failure. The inelastic force-deformation hysteretic behavior of the steel pedestals obtained from experimental test results is used to calibrate an analytical bridge model developed in OpenSees. The analytical bridge model is idealized based on a multi-span continuous bridge in Georgia that has been rehabilitated with steel pedestals. The analytical bridge model is subjected to a suite of ground motions to evaluate the performance of the steel pedestals and the overall bridge system. Recommendations are made to the Georgia Department of Transportation (GDOT) for the design and construction of steel pedestals. The results of this research are useful for Georgia and other states in low-to-moderate seismic zones considering the use of steel pedestals to elevate bridges and therefore reduce the likelihood of over-height vehicle collisions.

Due to the kinematic limitation of slider-crank mechanisms used in traditional internal combustion engines, such devices driven by their piston motions have a difficulty to reach the better fuel efficiency. In order to make the fuel efficiency better, many engine mechanisms that can be tuned to obtain desired piston motions have been proposed. Since most of the proposed engine mechanisms have complex linkages and bulky size, they become impractical for real applications. The design of a conjugate cam engine mechanism containing a conjugate cam with a slider crank mechanism can be conveniently tuned to produce a desired piston motion in consideration of a limited space, weight, and the number of linkages. The aim of this research is to set up a systematic design and analysis procedure for conjugate cam engine mechanisms. First of all, the kinematic analysis of conjugate cam engine mechanisms is performed based on the rigid body transformation method to determinate the conjugate cam profiles. Then, the geometric properties including the pressure angle and radius of curvature are investigated. Also, in order to characterize the rigid body dynamic behavior of the mechanism, the Newton¡¦s Law is used to derive equations of motion. Finally, it is conducted to design and analyze a real system, and observe the real condition from the experiment to prove the theory is correct.

This research presents a procedure for interactive segmentation and automatic tracking of moving objects in a video sequence. The user outlines the region of interest (ROI) in the initial frame; the procedure builds a refined mask of the dominant object within the ROI. The refined mask is used to model a spline template of the object to be tracked. The tracking algorithm then employs a motion model to track the template through a sequence of frames and gathers the 3D affine motion parameters of the object from each frame. The extracted template is compared with a previously stored library of 3D shapes to determine the closest 3D object. If the extracted template is completely new, it is used to model a new 3D object which is added to the library. To recreate the motion, the motion parameters are applied to the 3D object in a virtual environment. The procedure described here can be applied to industrial problems such as traffic management and material flow congestion analysis.

Intermittent Mechanisms are widely used in automation equipment, including delivery, assembly, and indexing systems. The aim of this research is to set up a systematic design and analysis procedure of a conjugate intermittent gear cam mechanism. The output of a conjugate intermittent gear cam mechanism is the intermittent motion of sun gear, which has a dwell function in a working period. The intermittent of sun gear is the combination of carrier constant rotation and planet gear variable rotation that is influenced by the conjugate cam profiles. This research first is to set up the design and analysis procedure including applications of rational B-splines to synthesis of output intermittent motion curve and the ALM optimization method for motion tuning to meet specific demands. Secondly, for kinematic analysis, the rigid body transformation methos is used to determinate the conjugate cam profiles so that the geometric analysis can be performed. Then, the rigid body dynamic behavior of the mechanism is analyzed. Finally, to verify the usefulness and effectiveness of the developed procedure, it is conducted to design and analyze a real paper conveyor system of a die cutting and creasing machine. The research results obtained in this study have been applied in the industry due to its validation.

<p>The following report contains an evaluation of the use of mathematical simulation programs at the company Isaberg Rapid AB. The work includes booth FE and motion simulations where the results are compared with real life test data.</p><p>The goal of the report is to evaluate the accuracy of simulations which can be performed by engineers as a part of the design process. By using mathematical simulation tools it is possible to find a good design solution early in the development phase and thereby shorten lead time and reduce costs.</p>