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<p>Russian realist writer Ivan Turgenev wrote Fathers and Sons in 1861, the middle of the politically, socially and ideologically eventful nineteenth century. While the turbulent historical moment is certainly reflected in the imagined landscape of the novel, Turgenev's text is first and foremost a literary work with implications that extend beyond the moment of its conception. Through allusions to the classical pastoral and juxtaposition of social and economic hardship, Turgenev creates a disconcerting ironic pastoral, or Russian Arcadia, that is marked by tension between a discordant ideal and reality. Resolution can be achieved in two ways that mirror nature's duality: one may become brutal, nihilistic and destructive, or one may strive for harmony and endure with the earth. By contemplation of one's own nature and the limits imposed by culture and nature itself, Turgenev demonstrates that the individual can come to this harmony, or an adaptive equilibrium that is characterized by balance, stability, and enjoyment of sensory experience. </p> <p>Turgenev's ironic pastoral, his concern with human brutality and the madness attendant upon it, the recognition of boundaries, and the sensory as an enduring mode of experience and communication are revisited and reworked by Ukrainian-Canadians in the twentieth century. The 1987 anthology, Yarmarok: Ukrainian writing in Canada since the Second World War, represents one of the most comprehensive collections of Ukrainian-Canadian writing in English and brings together both accomplished and previously unpublished writers that include: Mykola Ponedilok, Ruth Andrishak, Wasyl Sofroniw Levytsky, Stefania Hurko, Oleh Zujewskyj, Dennis Gruending, Maara Haas, and Bob Wakulich. These writers draw upon personal and family history and memory, which are haunted by the revolution Turgenev anticipated in Fathers and Sons, to relate their Arcadias, and the equilibriums they envision for individuals striving for balance within the limits imposed by the Canadianizing environment.</p> / Thesis / Master of Arts (MA)

If we adjoin the cube root of a cube free rational integer <i>m</i> to the rational numbers we construct a cubic field. If we adjoin the cube roots of distinct cube free rational integers <i>m</i> and <i>n</i> to the rational numbers we construct a bicubic field. The number theoretic invariants for the cubic fields and their normal closures are well known. Some work has been done on the units, classnumbers and other invariants of the bicubic fields and their normal closures by Parry but no method is available for calculating those invariants. This dissertation provides an algorithm for calculating the number theoretic invariants of the bicubic fields and their normal closure. Among these invariants are the discriminant, an integral basis, a set of fundamental units, the class number and the rank of the 3-class group. / Ph. D.

In the first part of this study, the dynamic behavior of a cracked rotating shaft with a rigid disk is analyzed, with an ideal and a nonideal motor, passing through its critical speed. The shaft contains a single transverse crack that is assumed to be either completely open or completely closed at any given time, depending on the curvature of the shaft at the cross section containing the crack. Flexible, damped supports and overhangs with a mass at one end are included. The supports are modeled with elastic springs and dashpots. The influence of gyroscopic moments of the disk (with an ideal motor) is investigated. For a nonideal motor, there is an interaction between the shaft and the motor. Eccentricity of the disk, gravitational forces, and internal and external damping are included. The equations of motion and boundary conditions are derived by Hamilton's Principle. To eliminate the spatial dependence, the Extended Galerkin Method is applied. Longitudinal vibration, shear deformation and torsional vibration are neglected. In the second part of this study, the vibration suppression of a cracked, simply supported, rotating shaft with a rigid disk is discussed, with an ideal and a nonideal motor, passing through the critical speed. The use of a flexible internal constraint is introduced to suppress the vibration. By activating this additional internal support, the shaft is prevented from passing its critical speed. Transient motions occur at the time of activation or deactivation of the constraint. The maximum displacement of the shaft during acceleration (run-up) or deceleration (coast-down) can be reduced significantly by appropriate application of this flexible internal support. / Ph. D.

While interactive design tools, rapid prototyping tools, and user interface management systems (UIMSs) are advancing as cost-effective ways of producing interfaces, attention to usability is rarely incorporated into such tools. The advancement of producing interfaces more rapidly without addressing their quality is of limited worth. This thesis reports on the design and prototype implementation of a software tool, IDEAL (Interface Design Environment and Analysis Lattice), that encourages and enables user-centered design as an integral part of the user interface development process. IDEAL integrates usability engineering techniques and behavioral task representations with a graphical hierarchy of associated user tasks to support formative evaluation of an evolving user interface. IDEAL supplements the functionality of current interface construction tools by focusing on usability through user-centered design. IDEAL was designed and developed using the techniques it supports: formative evaluation and iterative refinement. Representative users participated in two phases of qualitative formative evaluations from which critical incidents, verbal protocol, and qualitative data were collected. Feedback from each phase contributed to the revised design of IDEAL. This empirical evaluation showed IDEAL to be useful as an automated tool for managing the interrelated tasks of interface development, including design, usability specification definition, and formative evaluation, that are currently performed manually (e.g., using pencil and paper.) / Master of Science

Active suspension technologies are well known for improving ride comfort and handling of ground vehicles relative to passive suspensions. They are ideally suited for mitigating single-event road obstacles. The work presented in this thesis aims to develop a structured approach for finding the peak force and bandwidth requirements of actuators for active suspensions, to mitigate single-event road obstacles. The approach is kept general to allow for application to different vehicle models, ride conditions and performance objectives. The current state-of-art in active suspensions was first evaluated. Based on these findings, the objectives of the simulation models and approach was defined. A quarter-car model was developed in Matlab to simulate the behavior of active suspensions over unilateral boundary conditions due to different road obstacle profiles. The obstacle profiles were obtained from existing standards and literature and then processed to replicate the interaction of tires on road. A least-mean-squares (LMS) algorithm for adaptive filtering, with the help of look-ahead preview was used to determine the ideal control force profile to achieve the performance objective of the active suspension. A case study was conducted to determine the requirements of the actuator in terms of bandwidth and peak force for different single-event road obstacle profiles, vehicle speeds and look-ahead preview distances. The results of the study show that the vehicle velocity and type of road obstacle have a strong influence on the required peak force and bandwidth of the actuator, while look-ahead preview will be much more important for real time controller implementation. / Master of Science

Indoor spaces have become increasingly prevalent in human lives. While scholarship in other fields has studied the relationship between humans and the indoors, it has not been readily investigated in Geography. This study draws from prior research in Building Design, Managerial Science, and Education to examine the relationship between building users and resources in indoor spaces. To better understand how users seek resources in an indoor, academic space, this research asks: (1) what spaces and resources do building users value?; and (2) how are their perceptions of value associated with observed measures of occupancy? This research takes place in Goodwin Hall, on the Blacksburg campus of Virginia Polytechnic Institute and State University. This research relies on surveys conducted in 2018 as well accelerometer data collected in 2018 to examine the relationship between users' perception and use of resources in informal learning environments. Through quantitative analysis this research tests the ideal free distribution hypothesis. Findings indicate that certain measures of use and value support the ideal free distribution hypothesis. These results help to lay a groundwork for future geographic research in indoor spaces. / Master of Science / Indoor spaces have become increasingly created, used, and occupied by humans. Geography, as a discipline, has traditionally studied the relationship that humans have with their surrounding outdoor environments. This research studies how humans interact with their indoor environments. Other disciplines, such as Building Design, Managerial Science, and Education have examined how indoor spaces can impact human movement, behavior, and choice. Geography is a spatial discipline (observes how variables affect each other over space) and offers a differing lens to view human-indoor relationships. To better understand how users seek resources in an indoor, academic space, this research asks: (1) what spaces and resources do building users value?; and (2) how are their perceptions of value associated with observed measures of occupancy? This research takes place in Goodwin Hall, on the Blacksburg campus of Virginia Polytechnic Institute and State University. This research relies on surveys conducted in 2018 as well accelerometer data, which observes the amount of acceleration, collected in 2018 to examine the relationship between how users' view and use resources and spaces within an indoor environment. Through quantitative analysis this research tests the ideal free distribution hypothesis. Findings show that certain measures of use and value support the ideal free distribution hypothesis. Findings from this paper help to provide more insight into how humans interact with indoor spaces and lays the groundwork for future indoor geographic research.

The aim of suspension systems in vehicles is to provide the best balance between ride and handling depending on the operating conditions of a vehicle. Active suspensions are far more effective over a variety of different road conditions compared to passive suspension systems. This is because of their ability to store and dissipate energy at different rates. Additionally, they can even provide energy of their own into the rest of the system. This makes active suspension systems an important topic of research in suspension systems. The biggest benefit of having an active suspension system is to be able to provide energy into the system that can minimize the response of the sprung mass. This is done using actuators. Actuator design in vehicle suspension system is an important research topic and a lot of work has been done in the field but little work has been done to estimate the peak control force and bandwidth required to minimize the response of the sprung mass. These two are very important requirements for actuator design in active suspensions. The aim of this study is estimate the peak control force and bandwidth to minimize the acceleration of the sprung mass of a vehicle while it is moving on a compliant surface. This makes the road surface a bi-lateral boundary and hence, the total system is a combination of the vehicle and the compliant road. Generalized vehicle and compliant road models are created so that parameters can be easily changed for different types of vehicles and different road conditions. The peak control force is estimated using adaptive filtering. A least mean squares (LMS) algorithm is used in the process. A case study with fixed parameters is used to show the results of the estimation process. The results show the effectiveness of an adaptive LMS algorithm for such an application. The peak control force and the bandwidth that are obtained from this process can then be used in actuator design. / Master of Science / Active suspension systems have been proven to be a better option compared to passive suspension systems for a wide variety of operating conditions. Active suspensions typically have an actuator system that produces a force which can reduce the disturbance caused by road inputs in the suspension. The sprung mass of a vehicle is the mass of the body and other components supported by the suspension system and the un-sprung mass is the total mass of the components which are not supported by the suspension or are part of the suspension system. The actuator is typically between the sprung mass and the un-sprung mass. When there is a single event disturbance from the road, the energy is transferred to the sprung mass, which contains the occupants, through the un-sprung mass. The actuator produces a force that reduces this acceleration in the sprung mass and hence improves ride comfort for the occupants of the vehicle. In this thesis, the single event disturbance that has been considered is a compliant road surface. This is a bi-lateral boundary since the vehicle interacts with the compliant elements under the surface of the ground. The aim of this thesis is to develop and implement a method to estimate the peak control force and bandwidth that the actuator needs to produce to eliminate or reduce the acceleration of the sprung mass which is caused by the compliant surface single event disturbance.

Most commercial vehicles currently on the market are still equipped with a passive suspension system, while some luxury brands may already use an adaptive suspension. Active suspension systems on the other hand are rarely found, however, they offer great opportunities to close the gap of the well-known trade-off between ride comfort and handling. Besides that, they can also be used to mitigate single event disturbances, an objective of the USA army as announced in a solicitation which initiated and motivated this research. In addition to that, several studies were found stating the impact and danger of potholes and their impact on the vehicle and passenger. Reviewing the literature, several control strategies for controlling active suspension systems were found. However, most of these approaches used feedback control and did not try to mitigate single event disturbances. Since literature also suggested making use of look ahead preview, research at the Performance Engineering Research Lab at Virginia Tech was started in 2015 combining look ahead preview and an adaptive system to generate optimal force profiles. This introductory research succeeded and proved the used approach to be very promising. However, the used adaptive system was not designed to operate in real-time and did not show any correlation between different road profiles. Therefore, the main objective of this research project is to evaluate and analyze each of the adaptive systems by searching for correlations in their solutions. The results then should be used in order to design a control law which emulates the adaptive system and can be used in a real-time environment. First, an overall research methodology was derived. According to this a software application was developed which extracts ideal force profiles from single event disturbance signals in order to mitigate their impact to the vehicle. The application uses a quarter car model with a partially loaded active suspension system, a set of predefined road profiles, a road profile preprocessor, and an adaptive algorithm. The preprocessing includes geometric filtering using a Tandem-Cam Model and the adaptive processor used an iterative version of the Filtered-X Last-Mean-Square algorithm. During evaluation and analysis of several generated data sets, high correlations in the generated and adjusted adaptive systems were discovered. From these an empirical and theoretical universal filter model was derived, which was then used to design an open-loop control law named Optimal Force Control. The original control law and an adjusted version designed for a real-time environment were tested for all predefined road profiles over all considered vehicle velocities and prove to perform much better than the offline solution using the adaptive system. In summary, a control law named Optimal Force Control was designed which can be used and implemented in a vehicle to extract an analytical and ideal force profile given a road profile input. Implementing an active suspension system with tracking controller, this approach can be used in order to mitigate single event disturbance signals by reducing the vertical vehicle acceleration. / Master of Science / Most commercial vehicles currently on the market are still equipped with a suspension system consisting of springs and shock absorbers (passive suspensions), while some luxury brands already use suspension systems including parts which can change their behavior based on the driving situation (active suspensions). While these active suspension systems are still rarely found, they offer great opportunities to make the vehicle stable and at the same time easy to handle. Also, they have the potential to reduce the risk of an accident while driving over a pothole or disturbance in the road, an objective of the USA Army as announced in a solicitation which initiated and motivated this research. Reviewing the literature, several control strategies for controlling active suspension systems were found. However, most of these approaches required measuring the current state of the suspension system. Research at the Performance Engineering Research Lab at Virginia Tech was started in 2015 in order to control active suspension systems by using data of the road profile ahead of the vehicle. This introductory research succeeded and proved the approach used to be very promising. However, the used system was designed to work in a laboratory environment only. Therefore, the main objective of this research project was to evaluate and analyze the used control strategy by searching for intersections and similarities in the different solutions. The results were then used to design a control strategy which can be applied in a real-world vehicle environment. First, an overall research methodology was derived. According to this methodology a software application was developed that generates the ideal control signal for the active suspension system in order to reduce the impact of a disturbance in the road profile. To that end a set of predefined road profiles were used, and a computer algorithm called Filtered-X Last-Mean-Square algorithm calculated the ideal control signal for the active suspension system. During the evaluation and analysis of several generated data sets, a lot of intersections and similarities were discovered. Based on these findings a new control strategy was designed in order to be implemented into a real-world vehicle environment. The new control strategy for the real-world vehicle environment was tested for all predefined road profiles over all considered vehicle velocities and proved to outperform the control strategy for the laboratory environment. In summary, a new control strategy named Optimal Force Control was designed, which can be used and implemented in a vehicle. The implementation of an active suspension system can be used to mitigate disturbances in the road by reducing the vertical vehicle acceleration.