This thesis discusses a minimized number of concepts necessary for creating stateful, asynchronous, and scalable software applications that implement a subject domain. It is shown how domain driven design can be implemented using a minimized set of interfaces and architecture patterns. Further, it is shown how high-level business logic can be exposed as an HTTP service. This is achieved by reviewing requirements, design, and implementation details for shared control of an organizational data structure - a tree. Tree data specific as well as general business logic such as synchronization is identified and testing results are explored. Extensibility design is proposed. / Thesis / Master of Applied Science (MASc)

Organizations often take trust for granted or ignore it, although trust is important for organizational learning and performance. Organizations must continuously learn if they are to survive, and trust facilitates individual and organizational learning. However, many authors either mention the importance of trust, or assume trust is present, and then discuss other topics as if little can be done to better understand the antecedents of trust or to improve trust in an organization. In particular, prior to this study, researchers had not explored the influence of adult attachment and disclosiveness on organizational trust. Human resources development professionals can play a vital role by helping leaders in their organizations attain strategic goals, however, no research study done previously has focused on how trust in an organization is influenced by adult attachment and disclosiveness. There is a need to better understand organizational trust because in today's global economy, an organization's ability to survive may depend in part on individual and organizational learning facilitated by trust. This study focused on a main research question "What portion of the variance in employees' perceptions of organizational trust do employees' adult attachment and disclosiveness explain?" During this research, a revised instrument for measuring organizational trust was developed. The findings of this study showed that disclosiveness did not have a statistically significant influence on organizational trust. In contrast, fearful attachment, in particular was shown to have a modest, statistically significant, and negative influence on organizational trust. / Ph. D.

Communication delay in distributed teams is salient problem, especially in operational setting where communication is critical to team safety and success. The present study investigated the impact of communication delays affect distributed team performance and processes, and if being able to see one's team member would lessen the effects of delays. In addition, team gender composition was investigated, to see how delays affected the interactions of same and mixed-gender teams, as well as teams with familiar and unfamiliar members. Lastly, a supplemental was performed on a subset of the experimental data to determine if teams with familiar members' communicated more efficiently than unfamiliar teams when coordination complexity was high. Thirty distributed dyads, were assigned the role of intelligence analysts, and performed a collaborative problem solving task, using audioconferencing and videoconferencing technologies. During the task, participants verbally shared and discussed information in order to solve a fictitious terror plot. Communication between team members was delayed by 0 ms, 800, or 1600 ms. Linear mixed models showed that participants took longer to solve the task at the 800 ms delay. Task accuracy was not affected by delays. At the 1600 ms delay, participants shared less information with each other, and rated their frustration higher compared to the 0 ms delay. Audiovisual technology affected overall workload scores, with lower scores at the 0 ms delay compared to the 800 ms delay. Although delays did not have the anticipated effect on familiar and same-gender teams, there were some interactive effects of interest. Specifically, in gender-diverse teams task accuracy was higher with audiovisual technology than audio-alone, but this effect was independent of delays. Also, familiar teams exhibited higher levels of cognitive trust across all levels of delay and technology. Results of the supplemental analysis showed no differences in communication efficiency between familiar and unfamiliar teams when coordination complexity was high. Based on the results of this work, recommendations were proposed for strategies to lessen the effects of communication delays and future research directions were outlined. / Doctor of Philosophy / Communication delay in distributed teams is salient problem, especially in operational settings where communication is critical to team safety and success. In previous work, communication delays have been shown to disrupt turn-taking in conversations and create instances of overlaps or interruptions. The present study was conducted to further investigate the effects of communication delays on various aspects of distributed team performance and to determine if being able to see one’s team member via video technology may potentially lessen the effects of delays. In addition, team gender composition was investigated, to see how delays affected the interactions of same and mixed-gender teams, as well as teams with familiar and unfamiliar members. Lastly, a supplemental analysis was performed using a subset of the experimental data to determine if teams with familiar members’ communicated more efficiently than unfamiliar teams when coordination complexity was high. Thirty distributed teams of two members or dyads, performed a collaborative problem solving task, using audio conferencing and videoconferencing technologies. During the task, participants verbally shared and discussed information in order to identify the solution to a fictitious terror plot. Communication between team members was delayed by 0 ms, 800, or 1600 ms. Overall, results showed that participants took longer to solve the task at the 800 ms delay, with no effects on task accuracy. At the 1600 ms delay, participants shared less information with each other, and rated their frustration higher compared to the 0 ms delay. When teams used audiovisual technology, workload scores were lower at 0 ms compared to the 800 ms delay. Although delays did not have the anticipated effects on familiar and same-gender teams, there were some other interesting effects that emerged. Namely, gender-diverse teams scored higher accuracy with audiovisual technology than audio-alone, but this effect was independent of delays. Also, teams with familiar members exhibited higher levels of cognitive trust across all levels of delay and technology. Results of the supplemental analysis showed that unfamiliar teams communicated more efficiently with audiovisual technology, but only when coordination complexity was low.

The present study investigated the relationship between collective leadership, team trust, and team performance longitudinally and with the inclusion of a performance feedback loop. Collective leadership was hypothesized to mediate the relationship between team trust and team performance; however, this hypothesis was not supported. Additional analyses support the conceptualization of collective leadership as an emergent state because collective leadership density increased significantly across two time-points. Further hypothesis testing revealed performance feedback to influence subsequent levels of team trust. / Master of Science

For parameter inversion problems governed by systems of partial differential equations, such as those arising in Diffuse Optical Tomography (DOT), even the cost of repeated objective function evaluation can be overwhelming. Despite the linear (in the state variable) nature of the DOT problem, the nonlinear parameter inversion process is dominated by the computational burden of solving a large linear system for each source and frequency. To compute the Jacobian for use in Newton-type methods, an adjoint solve is required for each detector and frequency. When a three-dimensional tomography problem may have nearly 1,000 sources and detectors, the computational cost of an optimization routine is a large burden. While techniques from model order reduction can partially alleviate the computational cost, obtaining error bounds in parameter space is typically not feasible. In this work, we examine two different remedies based on stochastic estimates of the objective function. In the first manuscript, we focus on maximizing the efficiency of using stochastic estimates by replacing our objective function with a surrogate objective function computed from a reduced order model (ROM). We use as few as a single sample to detect a misfit between the full-order and surrogate objective functions. Once a sufficiently large difference is detected, it is necessary to update the ROM to reduce the error. We propose a new technique for improving the ROM with very few large linear solutions. Using this techniques, we observe a reduction of up to 98% in the number of large linear solutions for a three-dimensional tomography problem. In the second manuscript, we focus on establishing a robust algorithm. We propose a new trust region framework that replaces the objective function evaluations with stochastic estimates of the improvement factor and the misfit between the model and objective function gradients. If these estimates satisfy a fixed multiplicative error bound with a high, but fixed, probability, we show that this framework converges almost surely to a stationary point of the objective function. We derive suitable bounds for the DOT problem and present results illustrating the robust nature of these estimates with only 10 samples per iteration. / Doctor of Philosophy / For problems such as medical imaging, the process of reconstructing the state of a system from measurement data can be very expensive to compute. The ever increasing need for high accuracy requires very large models to be used. Reducing the computational burden by replacing the model with a specially constructed smaller model is an established and effective technique. However, it can be difficult to determine how well the smaller model matches the original model. In this thesis, we examine two techniques for estimating the quality of a smaller model based on randomized combinations of sources and detectors. The first technique focuses on reducing the computational cost as much as possible. With the equivalent of a single randomized source, we show that this estimate is an effective measure of the model quality. Coupled with a new technique for improving the smaller model, we demonstrate a highly efficient and robust method. The second technique prioritizes robustness in its algorithm. The algorithm uses these randomized combinations to estimate how the observations change for different system states. If these estimates are accurate with a high probability, we show that this leads to a method that always finds a minimum misfit between predicted values and the observed data.

There are many leadership theories that dominate the field of Industrial and Organizational Psychology, however there is a lack of understanding as to which leadership processes may be most appropriate for action teams in high stress environments. Previous research has articulated leadership behaviors, but has largely ignored the temporal processes of leadership, and how it changes throughout the operating team’s tenure. The proposed study investigates two types of leadership, namely shared and autocratic leadership, that take place during critical steps of the perioperative process and relates these leadership behaviors to team dynamics and psychological processes. Specifically, this study builds upon other studies by testing how leadership behaviors are related to levels of psychological safety and the optimization of teamwork and communication among team members. We were also interested in understanding if the surgeon’s perception of past performance of their team has an impact on the amount of trust the leader has in his/her team and if this in turn, has an impact on the type of leadership utilized during the team’s tenure. As an exemplar environment, we explored these dynamics in the operating theater, which is a high stakes environment requiring both technical and non-technical skills, such as leadership, communication, and teamwork. Results show that the correlation between the surgeon’s perceived past performance of the team and the trust the surgeon has in his/her team and the relationship between team’s trust and teamwork and communication were significant at the alpha =.1 level. All other relationships were non-significant. / M.S. / In the field of Industrial and Organizational Psychology, many leadership theories have been developed, however, there is a lack of understanding as to which type of leadership is best for teams who work in high-stress environments, such as the operating room. This study looks at two types of leadership: shared leadership and autocratic leadership. Shared leadership is when all team members emerge and have a leadership role, whereas autocratic leadership is when one person makes all the decisions without consulting other team members. Previous research has articulated leadership behaviors, but has largely ignored the temporal processes of leadership, and how it changes over time throughout the surgical procedure. This study builds upon other studies by testing how leadership behaviors are related to levels of psychological safety and the optimization of teamwork and communication among team members. We were also interested in understanding if the surgeon’s perception of past performance of their team has an impact on the amount of trust the leader has in his/her team and if this in turn, has an impact on the type of leadership utilized during the team’s tenure. As an exemplar environment, we explored these dynamics in the operating theater, which is a high stakes environment requiring both technical and non-technical skills, such as leadership, communication, and teamwork. Results show that the relationship between the surgeon’s perceived past performance of the team and the trust the surgeon has in his/her team is significant and the relationship between the trust the surgical team members have in each other and the amount that they communicate with each other is also significant.

Numerical noise is a prevalent concern in many practical optimization problems. Convergence of gradient based optimization algorithms in the presence of numerical noise is not always assured. One way to improve optimization algorithm performance in the presence of numerical noise is to adjust the method of gradient computation. This study investigates the use of Continuous Sensitivity Equation (CSE) gradient approximations in the context of numerical noise and optimization. Three problems are considered: a problem with a system of ODE constraints, a single parameter flow problem constrained by the Navier-Stokes equations, and a multiple parameter flow problem constrained by the Navier-Stokes equations. All three problems use adaptive methods in the simulation of the constraint and are numerically noisy. Gradients for each problem are computed with both CSE and finite difference methods. The gradients are analyzed and compared. The two flow problems are optimized with a trust region optimization algorithm using both sets of gradient calculations. Optimization results are also compared, and the CSE gradient approximation yields impressive results for these examples. / Master of Science

Effective collaboration between humans and autonomous agents can improve productivity and reduce risks of human operators in safety-critical situations, with autonomous agents working as complementary teammates and lowering physical and mental demands by providing assistance and recommendations in complicated scenarios. Ineffective collaboration would have drawbacks, such as risks of being out-of-the-loop when switching over controls, increased time and workload due to the additional needs for communication and situation assessment, unexpected outcomes due to overreliance, and disuse of autonomy due to uncertainty and low expectations. Disclosing the information about the agents for communication and collaboration is one approach to calibrate trust for appropriate reliance and overcome the drawbacks in human-autonomy teaming. When disclosing agent information, the level of detail (LOD) needs careful consideration because not only the availability of information but also the demand for information processing would change, resulting in unintended consequences on comprehension, workload, and task performance. This dissertation investigates how visualization design at different LODs about autonomy influences transparency, trust, and, ultimately, the effectiveness of human autonomy teaming (HAT) in search and rescue missions. LOD indicates the amount of information aggregated or organized in communication for the human to perceive, comprehend, and respond, and could be manipulated by changing the granularity of information in a user interface. High LOD delivers less information so that users can identify overview and key information of autonomy, while low LOD delivers information in a more detailed manner. The objectives of this research were (1) to build a simulation platform for a representative HAT task affected by visualizations at different LODs about autonomy, (2) to establish the empirical relationship between LOD and transparency, given potential information overload with indiscriminate exposure, and (3) examine how to adapt LOD in visualization with respect to trust as users interact with autonomy over time. A web-based application was developed for wilderness SAR, which can support different visualizations of the lost-person model, UAV path-planner, and task assignment. Two empirical studies were conducted recruiting human participants to collaborate with autonomous agents, making decisions on search area assignment, unmanned aerial vehicle path planning, and object detection. The empirical data included objective measures of task performance and compliance, subjective ratings of transparency, trust, and workload, and qualitative interview data about the designs with students and search and rescue professionals. The first study revealed that lowering LODs (i.e., more details) does not lead to a proportional increase in transparency (ratings), trust, workload, accuracy, and speed. Transparency increased with decreased LODs up to a point before the subsequent decline, providing empirical evidence for the transparency paradox phenomenon. Further, lowering LOD about autonomy can promote trust with diminishing returns and plateau even with lowering LOD further. This suggests that simply presenting some information about autonomy can build trust quickly, as the users may perceive any reasonable forms of disclosure as signs of benevolence or good etiquette that promote trust. Transparency appears more sensitive to LOD than trust, likely because trust is conceptually less connected to the understanding of autonomy than transparency. In addition, the impacts of LODs were not uniform across the human performance measurements. The visualization with the lowest LOD yielded the highest decision accuracy but the worst in decision speed and intermediate levels of workload, transparency, and trust. LODs could induce the speed-accuracy trade-off. That is, as LOD decreases, more cognitive resources are needed to process the increased amount of information; thus, processing speed decreases accordingly. The second study revealed patterns of overall and instantaneous trust with respect to visualization at different LODs. For static visualization, the lowest LOD resulted in higher transparency ratings than the middle and high LOD. The lowest LOD generated the highest overall trust amongst the static and adaptive LODs. For visualizations of all LODs, instantaneous trust increased and then stabilized after a series of interactions. However, the rate of change and plateau for trust varied with LODs and modes between static and adaptive. The lowest, middle, and adaptive LODs followed a sigmoid curve, while the high LOD followed a linear one. Among the static LODs, the lowest LOD exhibits the highest growth rate and plateau in trust. The middle LOD developed trust the slowest and reached the lowest plateau. The high LOD showed a linear growth rate until a level similar to that of the lowest LOD. Adaptive LOD earned the trust of the participants at a very similar speed and plateau as the lowest LOD. Taking these results together, more details about autonomy are effective for expediting the process of building trust, as long as the amount of information is carefully managed to prevent overloading participants' information processing. Further, varying quantities of information in adaptive mode could yield very similar growth and plateau in trust, helping humans to deal with either the minimum or maximum amount of information. This adaptive approach could prevent situations where comprehension is hindered due to insufficient information or where users are potentially overloaded by details. Adapting LODs to instantaneous trust presents a promising technique for managing information exchange that can promote the efficiency of communication for building trust. The contribution of this research to literature is two-fold. The first study provides the first empirical evidence indicating that the impact of LODs on transparency and trust is not linear, which has not been explicitly demonstrated in prior studies about HAT. The impact of LOD on transparency is more sensitive than trust, calling for a more defined and consistent use of the term or concept - "transparency" and a deeper investigation into the relationships between trust and transparency. The second study presents the first examination of how static and dynamic LODs can influence the development of trust toward autonomy. The algorithm for adapting LOD for the adaptive visualization based on user trust is novel, and adaptive LODs in visualization could switch between detailed and abstract information to influence trust without always transmitting all the details about autonomy. Visualizations with different LODs in both static and adaptive modes present their own set of benefits and drawbacks, resulting in trade-offs concerning the speed of promoting trust and information quantity transmitted during communication. These findings indicate that LOD is an important factor for designing and analyzing visualization for transparency and trust in HAT. / Doctor of Philosophy / The collaboration between human and autonomous agents in search and rescue (SAR) missions aims to improve the success rate and speed of finding the lost person. In these missions, a human supervisor may coordinate with autonomous agents responsible for estimating lost person behavior, path planning, and unmanned aerial vehicles. The human SAR professional may rely on information from the autonomous agents to reinforce the search plan and make crucial decisions. Balancing the amount of information provided by the autonomous agents to the SAR professionals is critical, as insufficient information can hinder trust, leading to manual intervention, and excessive information can cause information overload, reducing efficiency. Both cases can result in human distrust of autonomy. Effective visualization of information can help study and improve the transmission of information between humans and autonomous agents. This approach can reduce unnecessary information in communication, thus conserving communication resources without sacrificing trust. This dissertation investigates how visualization design at the proper aggregation of details about autonomy, also referred to as level of detail (LOD), influences perceived understanding of the autonomous agents (i.e., transparency), trust, and ultimately, the effectiveness of human autonomy teaming (HAT) for wilderness SAR. A simulation platform was built for proof-of-concept, and two studies were conducted recruiting human participants to use the platform for completing simulated SAR tasks supported by visualizations at different LODs about autonomy. Study 1 results showed that transparency ratings increased with more details about autonomy up to a point and then declined with the most details (i.e., lowest LOD). Trust, workload, and performance also did not linearly improve with more details about autonomy. The non-linear relationships of LODs with transparency, trust, workload, and performance, confirmed the phenomenon of the transparency paradox, which refers to the disclosure of excessive information about autonomy may hinder transparency and subsequent performance. Study 2 results also illustrated that when visualization with LOD adapted to instant trust, the speed of building trust and the plateau of trust on autonomy can achieve the same level as the visualization provided with the most details, which performed the best in building trust. This adaptive approach minimized the amount of information displayed relative to the visualization, constantly presenting the most information, potentially easing the burden of communication. Taken together, this research highlights that the amount of information about autonomy to display must be considered carefully for both research and practice. Further, this dissertation advances the visualization design by illustrating that visualization adapting LODs based on trust is effective at building trust in a manner that minimizes the amount of information presented to the user.

Traffic congestion, high gas price and inadequate public transportation are major challenges for any country, business or individual. The traditional approach to solving these problems has been to improve public transportation and use greener energy. These approaches require huge investment, research and time, and can only be carried out by governments or businesses. An alternative solution seeks to reduce the number of vehicles on the road based on ridesharing. Nevertheless, ridesharing is not a popular form of public transportation. A ridesharing application involves planning and collaboration in setting up rides. Some of the concerns of users of these applications are social discomfort that arises due to lack of trust amongst co-passengers and inconvenience in scheduling rides. In this work we are trying to understand the perceptions of trust in a software application that integrates collaboration and social networks. We conducted a rideshare needs assessment survey conducted within the Virginia Tech community. The purpose behind this survey was to understand commuters travel patterns, their needs and to identify their preferences for private vehicles and public transit for a variety of travel needs. The survey results indicate that users are willing to increase participation in ridesharing programs if three core issues are addressed trust, convenience and incentives. Based on the results and analysis of our survey results we present an iPhone based ridesharing application that would leverage social networks to embed trust. To overcome the complexity in scheduling rides, we have made our application available on mobile phones (iPhone) so that users are connected on the go and make use of GPS for location awareness to plan their rides instantaneously. Our social software application is easy and intuitive to use, helps users find trusted rideshares and reduces the carbon footprint of the individual. / Master of Science

No / A recent paper in Accounting and Business Research by Lau et al. (2008) offers systematic evidence to explain whether managers’ perceptions on fairness of performance evaluation procedures affect attitudes such as job satisfaction; and if it does, the different behavioural processes involved. Our paper re‐examines Lau et al.’s model and hypotheses to assess the external validity of their findings, based on a very different sample of managers. Drawing on recent organisational justice literature, it further develops the model and examines the potential interaction effects of fairness of performance evaluation procedures and other variables on job satisfaction. Finally, it extends the outcome variable to include manager performance. Using survey responses from 165 managers, supported by 24 interviews, drawn from three major organisations in the manufacturing and financial services sectors, we find that Lau et al.’s results on the indirect effects of fairness of performance evaluation procedures on job satisfaction are generalisable to other organisational settings and managerial levels. However, using their model we do not find support for the outcome‐based effects through distributive fairness. Developing a revised model we observe that the effects of distributive fairness on job satisfaction are indirect via organisational commitment. When the model is further developed to incorporate performance as the outcome variable, we observe similar findings.