-
Prospective Students
-
Faculty and Staff
-
Current Students
-
Alumni and Friends
Autonomous exploration using mobile robots, commonly referred to as robotic exploration, entails simultaneously performing robot perception, localization, and motion planning to explore an unknown environment. Most prior indoor robotic exploration algorithms focus on exploring the entire environment. We consider exploration under deadlines dynamically imposed either by the robot’s battery or by the environment. Such time-sensitive robotic exploration is critical in dangerous environments as it provides vital initial information about the geometric structure and layout of the environment for subsequent operations. For instance, firefighters can utilize an initial map generated by this deadline constrained robotic exploration to rapidly navigate a building on fire. In the presence of deadlines, the robots should identify the semantically significant regions of the environment (e.g., corridors) and prioritize those that enable them to determine the environment's geometric structure and return to the starting position before the deadline.
This dissertation addresses the problem of autonomous exploration in indoor environments with dynamic deadlines. The problem is NP-hard and requires exponential time to solve optimally. Therefore, we present a short-horizon exploration algorithm, the priority-based greedy exploration algorithm, and several long-horizon exploration algorithms; these include adaptations of the orienteering problem and the profitable tour problem for single-robot and multi-robot exploration of unknown environments with dynamic deadlines. Furthermore, we present a test suite of environments and exploration metrics to benchmark the real-world efficiency of exploration algorithms in office-like environments. Our single-robot experiments reveal that the priority-based greedy exploration algorithm, which focuses on exploring semantic regions with higher connectivity, consistently outperforms the baseline cost-based greedy exploration algorithm in terms of environment layout identification and exploration efficiency. Moreover, the priority-based greedy algorithm was found to be on par with the computationally expensive long-horizon exploration algorithms in terms of percent of the area explored within the deadline. Long-horizon exploration algorithms on the other hand exhibit consistent performance with low variance over repeated experiments. Moreover, the multi-robot priority-based greedy exploration algorithm demonstrated better performance compared to the multi-robot baseline exploration algorithm and performed on par with the multi-robot long-horizon based exploration algorithm while being computationally faster.
Planning for secondary transition includes identification of postsecondary goals in the areas of continued education, employment, and independent living or community engagement (IDEA, 2004). Young adults with intellectual and developmental disabilities (IDD) lag behind their same-aged peers in outcomes related to community engagement (Lipscomb et al., 2017a); specifically, challenges related to travel and transportation are a well-documented barrier to community engagement that young adults with IDD experience (Deka et al., 2016; Kersten et al., 2020). The purpose of this dissertation was to examine the effects of constant time delay instruction on the ability of young adults with IDD to program and follow walking routes to unfamiliar community locations of their choice using the Google Maps application. Results indicated a functional relation between constant time delay instruction and the percent of steps three young adults with IDD completed for programming and following a Google Maps walking route. Additional measures included generalization to use of the Apple Maps application; social validity of the intervention, as reported by the participants and their special education teachers; and participants’ ability to problem-solve common issues that may occur when following a pedestrian route. Finally, study limitations, suggestions for future research, and implications for practice are described.
In recent years, there has been an increase in attacks, including advanced persistent threats (APTs), and the techniques used by the attacker in these attacks have reached unprecedented sophistication. Threat hunters use various monitoring tools to monitor and collect all these attack actions (which blend in with benign user activities) for cyber threat hunting—the end devices store monitored activities as generated logs/events. Moreover, Organizations like NIST and CIS provide guidelines (CSC) to enforce cyber security and defend against those attacks.
Although the end hosts and networking devices can record all benign user and adversary actions, it is infeasible to monitor everything. In existing approaches, high memory usage and communication overhead to transfer events to the central server create scalability issues on the monitored network. Single event matching on the end-host devices approach to detect attacks generates false alerts, causing the alert fatigue problem. This dissertation presents a distributed hierarchical monitoring agent architecture to overcome those limitations of existing tools and research works.
Additionally, there are no well-defined automated measures and metrics to validate the enforcement of CSC. Manually analyzing and developing measures and metrics to monitor and implementing those monitoring mechanisms are resource-intensive tasks and massively dependent on the security analyst's expertise and knowledge. To tackle those problems, we use LLM as a knowledge base and reasoner to extract measures, metrics, and monitoring mechanism implementation steps from CSC descriptions to reduce the dependency on security analysts with the help of few-shot learning with chain-of-thought prompting. This dissertation presents CSC enforcement assessment with the help of our distributed hierarchical monitoring agent architecture and prompt engineering.
This dissertation explores employee voice behaviors, specifically promotive voice and prohibitive voice. Literature acknowledges that employee voice behaviors are primarily measured at the individual level. However, there is a need for more research on employees' experiences or the potential influence that supervisors have on employees' voices (promotive and prohibitive) through actions such as supervisor incivility. Drawing from Conservation of Resource theory and the resource of Psychological Safety as the theoretical framework. This study reviews the interaction of experiences such as employee resiliency, threats to employee identity, and employee voice behaviors with moderating effects of supervisor incivility. A sample size of employees (N= 294) provides support for the relationship between employee resiliency and promotive voice behaviors. In addition, the study provides insights on practical implementation and future research in academia.
It is no secret that technological innovations have interrupted businesses in every sector, across all industries and the Accounting profession is no exception. Some of the most disruptive technologies include Artificial Intelligence, Big Data Analytics, Machine Learning, Blockchain and Robotic Process Automation and affect entry-level positions. The Big Four Accounting firms are now responding by investing in these technologies to stay ahead of the competition. Due to these significant investments, entry-level accountants need to acquire new technical skills to become employable. Using signaling theory as a springboard, my study seeks to examine whether job seekers with technology skills will apply to the accounting profession based on the investment signals from these firm. The study also examines the influences of perceived ease of use, perceived usefulness, gender and race.
Evaluating the impact of motherhood on a woman’s career is complex. There are interrelated mechanisms resulting in conflicting results. The wage disparity for mothers is noted within the literature to range from 0 – 20 percent, with a similar spectrum of negative impact on career progression, when compared with fathers and childless men and women. In this research I summarize the predominant theory-based explanations for the motherhood penalty and review a sample of the research published from 1979 to August 2023. This study shows evidence that a wage penalty for motherhood continues to persist ranging from 14 percent to 32 percent. From the NLSY97 sample of working women (2004-2021), there is evidence of a wage boost for married mothers, women who choose to delay fertility into their late 20s may experience a wage boost, race and a woman’s level of grittiness have no significant impact on women’s wages, and human capital considerations continue to matter and may work to attenuate any wage penalty for motherhood.
Conventional suture ligation of vascular tissues during surgery is time consuming and skill intensive. Alternative techniques require hemostasis through mechanical clips or sutures, which leave foreign objects in the body and disrupt the procedure through the need to exchange instruments. In recent years, energy-based devices, such as ultrasonic (US) and radiofrequency (RF) electrosurgical based technologies, have been used for rapid and efficient blood vessel ligation. These devices expedite numerous labor-intensive surgical procedures (including lobectomy, nephrectomy, gastric bypass, splenectomy, thyroidectomy, hysterectomy, and colectomy). However, both US and RF devices have limitations, including potential for unacceptably large collateral thermal damage zones, with thermal spread averaging greater than 1 mm. This lack of specificity prevents the use of these devices for delicate surgical procedures performed in confined spaces (such as prostatectomy). These device jaws take a long time to cool down to normal body temperature between successive procedures and may also cause thermal damage to healthy tissue through unintended heat conduction from contact with the device jaws.
A novel alternative method using near-infrared (IR) lasers for vessel ligation may eliminate some of these limitations of conventional energy-based devices. In this study, two real-time optical feedback systems are explored along with transparent jaw designs for sealing and bisection of blood vessels. This thesis begins with an introduction and theory of tissue optics followed by the methods used for the study. It describes the use of tissue autofluorescence as a real time optical feedback system. After that, it details the testing and comparison, both experimentally and computationally, of quartz and sapphire optical materials. These materials are transparent and bio-compatible, intended for use in the optical chamber, a critical component of the laparoscopic device jaw. Then, it describes a simultaneous IR laser vessel sealing and bisection study using a quartz optical chamber suitable for integration into a laparoscopic device, and the feasibility of using the optical signal originating from the therapeutic laser and transmitted through the cut vessel, as a closed-loop, optical feedback system for immediately deactivating the IR laser upon successful vessel bisection. The following part discusses future work followed by the summarization of the main accomplishments of this thesis.
In linear dynamics, bounded linear operators over infinite-dimensional Banach spaces have been shown to be able to exhibit interesting characteristics including topological transitivity, topological mixing, and even chaos in the sense of Devaney. This dissertation will examine weighted l^p sequence spaces together with the shift action as the operator. In the case the shift action is over the semi-group N, the above topological properties have been previously characterized by conditions on the weight sequence associated with a given weighted l^p space. This work will present recent results for new characterizations of these properties when the group action over a countable group is instead considered. Additionally, an example choice of the weight sequence in this setting will be presented which yields points which are periodic while having an infinite orbit.
Lastly, new implications for infinite and 0 topological entropy for the weighted l^p space with the shift action over N will be given. In particular, when the weight sequence is summable over a subset of N with positive upper density then infinite entropy may be achieved. Furthermore, when an arbitrary ratio of the weights is bounded above then 0 entropy is guaranteed.
ABSTRACT
CHRISTINE SISK. Effectiveness of Cardiac ERAS Multimodal Analgesia on Perioperative Pain in Adult Cardiac Surgery Patients. (Under the direction of Dr. KATHLEEN JORDAN)
Cardiac surgeries often rely on opioid analgesics, which can lead to adverse effects. The implementation of the multimodal analgesic approach, as a part of the ERAS protocol, has the potential to optimize intra- and postoperative pain management, leading to reduced opioid-related complications and improved patient outcomes. The purpose of this study was to evaluate the efficacy of multimodal analgesia within a Cardiac Enhanced Recovery After Surgery (ERAS) program in reducing postoperative pain and opioid consumption in adult cardiac surgery patients. This study compared the effects of cardiac ERAS multimodal analgesia against traditional opioid-based analgesia on postoperative pain and opioid consumption during the operation and the initial 24 hours postoperative.
The study was conducted at a level-one trauma center that had recently implemented the ERAS protocol on all cardiac surgical patients. Data was collected retrospectively from patients undergoing cardiac surgeries before and after the protocol’s implementation. The pre-ERAS group received traditional opioid-based analgesia, while the ERAS group received the ERAS multimodal analgesia protocol.
Data analysis revealed significantly lower intraoperative opioid consumption in the post-ERAS group compared to the pre-ERAS group (U = 1496.00, p = .026, z = -2.30). However, no statistically significant differences were observed in opioid consumption between the groups at 6 hours and 24 hours postoperatively. These findings suggest the ERAS protocol’s effectiveness in reducing intraoperative opioid requirements but limited impact on postoperative opioid consumption within the first 24 hours.
The study demonstrates that cardiac ERAS multimodal analgesia can effectively reduce intraoperative opioid consumption, highlighting its potential as a valuable component of perioperative pain management in cardiac surgery. While the findings did not show a significant reduction in postoperative opioid use, implementing such protocols can still offer benefits for patient care. This includes reducing opioid-related adverse effects and potentially improving patients’ overall recovery. Further research is needed to explore the longer-term impacts of multimodal analgesia on postoperative opioid consumption and patient outcomes in cardiac surgery.
Since initial applications in the latter twentieth century, the field of micro-optics has greatly expanded. Micro-optics now encompasses research in areas such as integrated optics, micro-electromechanical systems (MEMS), quantum technology, sensing, energy harvesting, and metamaterials. In its current stage, dynamically tunable micro-optics are crucial to providing additional processing power without increasing volume. Micro-structured optics comprise a subsection of micro-optics where the optical response is manipulated by some sub-wavelength or wavelength scale structure. One challenge in developing micro-structured optics are restrictions in terms of geometric freedom and extensive development times. As a solution to some of these challenges, rapid prototyping techniques such as two-photon polymerization (TPP) have been employed in the development of complex two- and three-dimensional optics. TPP provides nano-scale feature sizes, resolutions which surpass the diffraction limit of the light source. In search of ways to add additional degrees of tuning in micro-optics, the unique properties of TPP compatible resins can be exploited. In this study, dynamically tunable micro-structured optics are developed by TPP. Being a polymer, the fabricated structures have unique mechanical properties when compared with conventional glass and metal optics. The structures are designed such that their optical response is sensitive to induced mechanical stress or strain. Both sub-wavelength and wavelength-scale micro-structured arrays were investigated for this mechanical tuning. In each case, changes in the structure's geometry due to mechanical stimuli resulted in a change in the optical response. In combination with a MEMS device, the investigated structures could have applications in integrated optics, mechanical sensing and beamsplitting, and tunable bandgap filtering.
