Interactive narratives are marked by two characteristics: 1) a space of player interactions, some subset of which are specified as aesthetic goals for the system; and 2) the affordance for players to express self-agency and have meaningful interactions. As a result, players are (often unknowing) participants in the creation of the experience. They cannot be assumed to be cooperative, nor adversarial. Thus, we must provide paradigms to designers that enable them to work with players to co-create experiences without transferring the system's goals (specified by authors) to players and without systems having a model of players' behaviors. This dissertation formalizes compact representations and efficient algorithms that enable computer systems to represent, reason about, and shape player experiences in interactive narratives. Early work on interactive narratives relied heavily on "script-and-trigger" systems, requiring sizable engineering efforts from designers to provide concrete instructions for when and how systems can modify an environment to provide a narrative experience for players. While there have been advances in techniques for representing and reasoning about narratives at an abstract level that automate the trigger side of script-and-trigger systems, few techniques have reduced the need for scripting system adaptations or reconfigurations---one of the contributions of this dissertation. We first describe a decomposition of the design process for interactive narrative into three technical problems: goal selection, action/plan selection/generation, and action/plan refinement. This decomposition allows techniques to be developed for reasoning about the complete implementation of an interactive narrative. We then describe representational and algorithmic solutions to these problems: a Markov Decision Process-based formalism for goal selection, a schema-based planning architecture using theories of influence from social psychology for action/plan selection/generation, and a natural language-based template system for action/plan refinement. To evaluate these techniques, we conduct simulation experiments and human subjects experiments in an interactive story. Using these techniques realizes the following three goals: 1) efficient algorithmic support for authoring interactive narratives; 2) design a paradigm for AI systems to reason and act to shape player experiences based on author-specified aesthetic goals; and 3) accomplish (1) and (2) with players feeling more engaged and without perceiving a decrease in self-agency.

In modern multicore processors, various resources (such as memory bandwidth and caches) are designed to be shared by concurrently running threads. Though it is good to be able to run multiple programs on a single chip at the same time, sometimes the contention of these shared resources can create problems for system performance. Naive hard-partitioning between threads can result in low resource utilization. This research shows that simple and effective approaches to dynamically manage the shared cache can be achieved. The contributions of this work are the following: (1) a technique for dynamic on-line classification of application memory access behaviors to predict the usefulness of cache partitioning, and a simple shared-cache management approach based on the classification; (2) a cache pseudo-partitioning technique that manipulates insertion and promotion policies; (3) a scalable algorithm to quickly decide per-core cache allocations; (4) pseudo-LRU cache partition approximation; (5) a dynamic shared cache compression technique that considers different thread behaviors.

High performance networks of workstation are becoming increasingly popular a parallel computing platform because of their lower cost. Both message passing and software distributed shared memory (DSM) programming paradigms have been developed and employed on such distributed hardware platforms. An important performance bottleneck in these systems is the effective data transmission latency, which is poorer than in high-speed parallel computer interconnection networks. Iterative algorithms are used in a large class of applications like solution of partial algorithms are used, optimization problems, solutions to systems of linear equations, and so on. These can be parallelized in a straight-forward fashion with cad1 node computing a part of the data set and also synchronizing and exchanging data with the other nodes as required. But these synchronous version perform poorly when message transmission delays are high, as is the case in network of workstations. The asynchronous parallel version of these algorithms provide an additional degree of freedom to address large data transmission latencies. These algorithms do not synchronize, and behave correctly in the presence of losses and delays in the propagation of updates. Thus, in shared memory systems they do not synchronize accesses to shared data and they will work correctly even in the presence of delays and losses in updates. This gives synchronous algorithms a performance advantage over their synchronous counterparts since synchronization costs are avoided and further computation can be overlapped with communication. The message generation rate of asynchronous algorithms is however greater than that of their synchronous counterparts. Uncontrolled asynchronous runs can create a large network load resulting in large queuing delays, which in turn can increase the message generation of the asynchronous algorithms. This is especially possible in lower bandwidth network like that in network of workstations. Such a positive feedback loop leads to unstable network conditions. Recent work has tried to improve the performance of asynchronous algorithms on a distributed shared memory (DSM) system by adaptively buffering shared memory updates depending on the network load, and transmitting multiple updates together. This reduces congestion and message transmission overhead, but could still result in slow convergence since nothing is guaranteed about, the update propagation delay. Also, although adaptive throttling of message will kick in once the network gets heavily loaded, it cannot, prevent the initial flooding. Furthermore, the processor is not freed when computation with the available values does not result in much further convergence. In this thesis we present an alternate method of controlling iterative methods and present performance results for the same. We propose a new system-supported blocking read primitive, termed Global Read that is guaranteed to return a value of acceptable age of the specified location in a DSM system. The main idea is to enforce an upper bound on the age of shared updates seen by a node in a manner visible to the underlying system (DSM). Information about processes being blocked can be used for adapting the underlying system, especially the network, towards better performance. A reading process is throttled until its Global-Read is satisfied, thus implementing program-level flow control and also freeing the processor. The Global-Read can also help in communication-based scheduling of, processes. Performance evaluation using a benchmark from Cray, on a network of workstations and on the IBM SP2 parallel computer, showed good performance improvements. We also present results of a systematic study wherein we implement parallel code for different iterative techniques for the solution of Lap lace equation wing PVM, anti characterize when controlled asynchrony work befit. We studied the improvements in computation time and analyzed the sources of this improvement, using various input and parallelism, on both IBM SP2 and a network of workstations. We find significant performance improvements for controlling asynchrony when the traffic generated by the asynchronous algorithm becomes more than what can be sustained by the network. But we found that the scalability of the applications is limited by the software overhead for messages. Systems which have reduced software overhead will show very good scalable performance for controlled asynchrony.

This work analyzes human-in-the-loop robotic systems to determine where human input can be most beneficial to a collaborative task. This is accomplished by implementing a pick-and-place task using a human-in-the-loop robotic system and determining which segments of the task, when replaced by human guidance, provide the most improvement to overall task performance and require the least cognitive effort. The first experiment entails implementing a pick and place task on a commercial robotic arm. Initially, we look at a pick-and-place task that is segmented into two main areas: coarse approach towards a goal object and fine pick motion. For the fine picking phase, we look at the importance of user guidance in terms of position and orientation of the end effector. Results from this initial experiment show that the most successful strategy for our human-in-the-loop system is the one in which the human specifies a general region for grasping, and the robotic system completes the remaining elements of the task. We extend this study to include a second experiment, utilizing a more complex robotic system and pick-and-place task to further analyze human impact in a human-in-the-loop system in a more realistic setting. In this experiment, we use a robotic system that utilizes an Xbox Kinect as a vision sensor, a more cluttered environment, and a pick-and-place task that we segment in a way similar to the first experiment. Results from the second experiment indicate that allowing the user to make fine tuned adjustments to the position and orientation of the robotic hand can improve task success in high noise situations in which the autonomous robotic system might otherwise fail. The experimental setups and procedures used in this thesis can be generalized and used to guide similar analysis of human impact in other human-in-the-loop systems performing other tasks.

The purpose of this study is to examine the status of academic freedom and, more specifically, intramural and extramural speech at universities in the U.S. since 2000. Court opinions and briefs from benchmark court cases and the faculty's perspective of current academic freedom issues are analyzed to determine dominant trends and themes that have evolved since 2000. While others have studied the relationship between the First Amendment and academic freedom, this analysis brings current the discourse concerning the effect First Amendment court decisions have on the faculty speech. The central research question is to determine the effect court decisions have on the intramural and extramural speech of faculty and specifically to study how federal, state, and local events since 2000 have affected (a) the academic freedom of faculty in general, (b) the way universities handle faculty intramural speech, (c) the way universities handle faculty extramural speech when they speak both as a citizen and a public university employee, and (d) the ability of faculty to defend their academic freedom. Using post-modern theory, the two-phased mixed methods study deconstructs and analyzes (a) the six First Amendment court opinions and briefs and (b) the 19 interviews of public university faculty members. The first phase identified 11 dominant themes, which were used as the basis for the coding and the 19 interviews of public university faculty members. The interview coding and analysis identified 15 themes. Based on the Pearson Correlation Coefficient, four themes were identified in the court opinions and six in the interviews are discussed. The second phase also included surveys of the faculty interviewed and a quantitative analysis of the responses in order to classify the sample. The study found that public universities have complete control over academic freedom, and that it is a privilege granted to faculty based on their scholarly association with the university, not a right. Public university administrators, general counsels, deans, department chairs, and faculty will benefit from the study as it provides an intensive analysis of post-2000 court case logic and the current perceptions and apprehensions that faculty have concerning their intramural and extramural speech rights. / text

The purpose of this study was to explore how public elementary school principals develop teacher leadership capacity within their schools, as well as the effect of this effort on a school's performance. After examining a variety of sources, such as journal articles and web-based search engines, the researcher determined that there was scant information explaining the process principals undergo to create teacher leadership roles in an effort to develop a high-performing school. To accomplish the goals of this study, salient reports in the field of teacher leadership were reviewed. The insights afforded from these reports guided the researcher in developing a field-based investigation focusing on school leaders and teachers employed in three high-performing elementary schools in central Florida. The researcher explored features of teacher leadership that were evident in high-performing schools and sought to discover the characteristics principals seek in selecting new teachers. Also investigated were the teacher leadership opportunities created by the principals and the ways in which these roles helped to sustain the elementary schools' high performance. Furthermore, recent school-based decisions made by the school leaders were studied. Throughout the data, school administrators provided opportunities for teacher leadership within their schools, primarily by forming school-based committees. The results showed that principals solicited opinions from teachers, especially when it came to curriculum and instructional concerns. In addition, when sharing best practices or participating in staff-development opportunities with colleagues, teachers felt satisfied with their work environments. School leaders and teachers understood the roles they played in the overall success of their schools. Based on the results of this qualitative study, principals can build leadership capacity at schools by first establishing a culture of trust, honesty, and professionalism between themselves and the teachers. Next, school leaders provide and support opportunities for leadership by aligning teacher strengths and roles. The researcher recommends that future research in teacher leadership examine whether the principal's impact on teacher leadership has an affect on retention at the school level.

Shared social responsibility (SSR) has been increasingly promoted in sustainability research. While conceptual development has been expanded, empirical developments are still in their infancy. Extant SSR literature acknowledges that entities like industry, governments, consumers, and others must accept responsibility for achieving a common goal. However, a basic understanding of how consumers view this responsibility in the shared setting is lacking. Since collaborative efforts towards sustainability may be strategically more effective than individual efforts, this research investigates SSR from the consumers' perspective in order to determine how responsibility is assigned to the various entities involved in a specific form of sustainability, "green" product consumption. Perceptions of responsibility may influence future sustainability-minded consumer behavior; hence, this research offers relevant contributions for understanding the shared social dynamic. Utilizing elements of attribution theory, equity theory, and diffusion of responsibility, this research examined how ability, perceived consumer effectiveness, perceptions of equity, and group size influence consumer attribution of responsibility for future "green" product consumption. Three experiments were conducted; the first two used an online scenario-based approach while the third was administered primarily at the University of Arizona. Data was analyzed using various statistical techniques, including multivariate analysis of variance to address the study hypotheses. Results established that consumers share responsibility for future "green" product consumption with corporations, government, and other consumers - but this responsibility is not shared evenly. Under most of the conditions evaluated, corporations, and government to a lesser degree, were attributed significantly more responsibility than consumers assigned themselves. The amount of effort required to use a "green" product, ability to positively change the environment, and equity of an interaction between a consumer and a manufacturer did not affect consumer attribution of responsibility. Group size had some impact, such that consumers who were not made explicitly aware of being in a group and those interacting with one other entity evenly shared responsibility for future "green" product consumption with the others involved. Consumers in larger groups assigned more responsibility to corporations than to themselves. Social loafing was determined not to be a factor in how consumers assigned responsibility in groups of various sizes.

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Η ανάπτυξη και εγκατάσταση συστάδων υπολογιστών (clusters) και διαδικτυακών πλεγμάτων υπολογισμού (computational grids), διαρκώς αυξανόμενη στις μέρες μας, διαμορφώνει ένα σαφώς κατανεμημένο περιβάλλον, ικανό για την εφαρμογή υπολογισμού στο εύρος του διαδικτύου. Στο πλαίσιο αυτό, η παράλληλη επεξεργασία καλείται να επωφεληθεί από την εγγύτητα των υπολογιστικών πόρων, όπως αυτή διαμορφώνεται από τα σύγχρονα δίκτυα υψηλών ταχυτήτων. Την ίδια στιγμή, οι προγραμματιστές παράλληλων εφαρμογών βρίσκονται σε δίλημμα ανάμεσα σε μοντέλα προγραμματισμού κοινής μνήμης ή κατανεμημένα. Με τα κατανεμημένα μοντέλα να αποτελούν την αρχική και πιο φυσική επιλογή στο περιβάλλον των συστάδων και των πλεγμάτων, ο προγραμματιστής έρχεται ξανά αντιμέτωπος με τα διαχρονικά προβλήματα που ενέχει η αποτύπωση του παραλληλισμού των εφαρμογών και ο προγραμματισμός με τη χρήση μοντέλων ανταλλαγής μηνυμάτων (message passing models). Έχοντας σαν στόχο την απαλλαγή του προγραμματιστή από τις δυσκολίες των κατανεμημένων μοντέλων, γίνεται σημαντική ερευνητική προσπάθεια για την υλοποίηση συστημάτων και εργαλείων που θα μπορέσουν να παρέχουν ένα αξιόπιστο περιβάλλον προγραμματισμού κοινής μνήμης, επιτυγχάνοντας ταυτόχρονα συγκρίσιμη απόδοση με τα αντίστοιχα μοντέλα ανταλλαγής μηνυμάτων. Ωστόσο, ένα από τα βασικά χαρακτηριστικά των σύγχρονων περιβαλλόντων υπολογισμού, που δυσχεραίνει την μεταφορά της υπάρχουσας τεχνολογίας συστημάτων κατανεμημένης κοινής μνήμης από τις συστάδες υπολογιστών στα πλέγματα, είναι η εκτεταμένη ετερογένεια που παρατηρείται στα συστήματα που συμμετέχουν σε ένα υπολογιστικό πλέγμα. Συμμετέχοντας στην προσπάθεια πρότασης ενός εύχρηστου και αποδοτικού περιβάλλοντος προγραμματισμού, καταρχάς σε συστάδες υπολογιστών και με την προοπτική επέκτασης σε υπολογιστικά πλέγματα, στο πλαίσιο της συγκεκριμένης μεταπτυχιακής εργασίας υλοποιείται το σύστημα Pleiad. To Pleiad αποτελεί ολοκληρωμένο πρωτότυπο της αφαίρεσης κατανεμημένης κοινής μνήμης σε επίπεδο λογισμικού (Software Distributed Shared Memory - SDSM). Κύριος στόχος, δεδομένης της ετερογένειας των σύγχρονων παράλληλων συστημάτων, είναι τόσο η μεταφερσιμότητα όσο και η διαλειτουργικότητα του συστήματος και γι' αυτό το λόγο επιλέγεται για την υλοποίηση του η πλατφόρμα Java. Το σύστημα Pleiad είναι σε θέση να αξιοποιήσει τη σύγχρονη τάση στα πολυεπεξεργαστικά συστήματα, όπως αυτή καθορίζεται από την ευρεία διάθεση επεξεργαστών πολλαπλών πυρήνων, επιτρέποντας την εκτέλεση πολυνηματικών εφαρμογών στο εύρος του κατανεμημένου συστήματος. Επιπλέον η υλοποίηση λαμβάνει χώρα σε επίπεδο χρήστη (user-level), προσδίδοντας στο σύστημα μεγαλύτερη ευελιξία στο περιβάλλον των ιδεατών οργανισμών (virtual organizations - VOs) που διαθέτουν συστάδες υπολογιστών στο πλαίσιο πλεγμάτων. Τα αποτελέσματα από την πειραματική σύγκριση του συστήματος Pleiad με συναφή συστήματα είναι ενθαρρυντικά. Σε κάθε περίπτωση το πρωτότυπο του συστήματος Pleiad όπως παρουσιάζεται στη μεταπτυχιακή εργασία, αποτελεί έργο υποδομής, με αρκετά ενδιαφέροντα ζητήματα ανοικτά στην προοπτική μελλοντικής ερευνητικής δραστηριότητας. / The development and the deployment of clusters and computational grids, continuously increasing in our times, clearly form a distributed environment that is able to conduct computation at the scale of the Internet. Under these circumstances, parallel processing is urged to utilize the proximity of the afforded computational resources as it is accomplished by the advancements on high speed networks. At the same time the parallel applications programmers are quite often up against a dilemma having to choose between shared memory or distributed memory programming models. While distributed memory programming models are the most typical choice in the field of clusters and grids, the programmer encounters well known obstacles during his effort to extract the parallelism of the application. Willing to release the programmer from the need to explicitly express parallelism through message passing orchestration, much research has been done to implement middleware that provides the abstraction of shared memory programming while at the same time achieves acceptable performance compared to other message passing models. Nevertheless, one of the most fundamental characteristics of the modern, distributed computing environments that encumbers porting the existing DSM technology from clusters to grids, is the broad heterogeneity of the afforded computing resources. Participating in the effort of providing a simple, robust and yet efficient programming environment, firstly designated for clusters with the intention support seamless parallel programming on top of grids, at the present thesis we present Pleiad. Pleiad consists our research prototype providing the abstraction of shared memory programming, implemented at the software level (Software Distributed Shared Memory - SDSM). Considering by default the heterogeneity of the contemporary parallel systems, we have defined as a target of the presented thesis to provide a simple portable and interoperable DSM system. That direction led us to choose Java as our development platform. Pleiad is also able to utilize the trend in modern multiprocessors as it is defined by the advent of multicore CPUs by enabling the execution of multithreaded applications on top of the distributed hardware architecture. Moreover, the implementation of Pleiad takes place at the user level, which is the most appropriate decision concerning the highly diverse environment of the virtual organizations that are formed as parts of a grid. The first results of the experimental evaluation of Pleiad compared to similar systems are emboldening. In any case the first prototype of Pleiad as it is presented in the current thesis provides the essential infrastructure that will be used to further address open issues concerning our research interests on the topic of distributed shared memory abstraction.

Control over nursing practice (CONP) is a participatory process through which nurses have input and engage in decision making about the context of practice and unit operations related to nursing practice. CONP has been associated with a number of positive outcomes related to nurse satisfaction, nurse status, effectiveness of patient care, and quality of patient outcomes. However, no comprehensive model has been created nor comprehensive analysis been conducted related to approaches for increasing CONP. This study tested a hypothesized model of antecedents to CONP developed from a review of the literature in nursing, psychology, and organizational management using a complexity theory perspective.The study used a nonexperimental, comparative design. The sample for data analysis consisted of 28 nurse managers and 583 staff nurses from 32 units in 10 hospitals. Existing instruments were used in a paper and pencil format to collect demographic and perceptual data on CONP and the hypothesized antecedent variables. Data were aggregated to provide an analysis of organizational and unit level contextual and variable effects related to CONP.Contextual regression indicated a greater influence of unit-level variables than organizational-level variables on nurses' perceptions of CONP. Regression analyses and revised model testing demonstrated that nurse manager supportiveness, implementation of a formal structure for CONP, and information flow consisting of open and accurate communication were positively related to CONP. Hierarchy of authority was negatively related to CONP. The relationship between CONP and job codification and autonomy varied based upon the measurement of the dependent variable. Manager's perception that participative decision making enhances organizational effectiveness; manager's perception that participative decision making does not reduce their power; nurses' experience, expertise, and educational preparation; and nurses' desire for control did not significantly relate to CONP as hypothesized.This study contributes to nursing research and clarifies strategies for improving the work environment for nurses by delineating antecedents to CONP in the acute care hospital setting. These data will be useful to nurses, nurse managers, and hospital administrators who want to improve patient safety, reduce patient mortality, increase nurse satisfaction, and increase nurse retention.