Spread-spectrum multiple access (SSMA) is conceptually attractive for interactive data communications over broadcast channel shared by a large number of potential users. The present thesis Involves a study of asynchronous direct sequence SSMA interactive data communication systems. The study includes a unified analysis and assessment of system delay-throughput performance. Two important message delay components which are affected by the design of the transmitter/receiver pair result from code acquisition and bit-errors. A new code synchronizer design featuring a number of parallel correlators is developed, and an analysis of synchronizer performance as it relates to SSMA applications is provided. It is shown that average acquisition delay decreases in proportion to Increase In the number of correlators when this number is small. Receiver bit-error probability for any given channel occupancy is derived. Three protocols suitable for SSMA transmissions under different operating conditions are proposed. Using one of these protocols, the expected number of transmissions before a message is received error-free is estimated by averaging bit-error probabilities over a postulated channel occupancy probability distribution. This distribution is verified using data obtained from channel simulations. Delay-throughput characteristics of the SSMA system are thus obtained by evaluating the above delays and other exogenous delays at various traffic levels. Results relevant to the given system and traffic models, transmission protocol, and transmitter/receiver structure are obtained assuming that users' codes are uncorrelated. Subsequently, it is shown that the results are easily modified to account for code cross-correlations. Assessment of SSMA delay-throughput performance Is accomplished by comparisons with pure ALOHA, slotted ALOHA and queueing channels. These comparisons necessitate extension of existing analysis of slotted ALOHA channels to include the effects of Gaussian channel noise, as well as development of an analysis procedure for noisy pure ALOHA channels. It is shown that in power-limited situations, the capacities of ALOHA and queueing channels can be maximized with respect to the transmission bit rate. Delay-throughput comparisons show that at throughput levels much lower than the capacities of these channels, average delays for SSMA are higher than those of the other channels. However, capacities of SSMA channels are generally higher than those of the other channels, which occupy only a fraction of the available bandwidth at power levels favourable to SSMA. In such cases, the throughput which results for a given delay clearly favours SSMA. Comparisons are also performed with respect to m-parallel ALOHA or queueing channels, where ra is the number of channels accommodated by the available bandwidth. In this case the capacities of SSMA channels are generally less than those of m-parallel slotted ALOHA or queueing channels, but approximately equal to those of m-parallel pure ALOHA channels. Therefore, SSMA presents a viable alternative to m-parallel pure ALOHA multiple access for interactive data communications. SSMA is especially favourable for transmissions of long messages In a wide-band broadcast channel with limited power. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

In this thesis, the author pursued two objectives. The first objective was to present a working example of a convenient, "idiot-proof", interactive computer program (designed with the user - not the programmer - in mind). The second objective was to investigate how various types of users interact with the computer, with the intention of reaching some conclusions about which program interfaces were most appropriate and convenient for various user types. In addition, some theories about the effects of various behavioural variables were investigated. The experimental tool used for this research was a simple interactive computer game in which the participants searched for the optimum profit in a three-dimensional space, given a fixed time limit. , Frequent periodic measurements were automatically collected on user performance, attitude, requests for reports, utilization of special features, and other variables; also, the solution protocol of each participant was recorded. The users were cateqorized by coqnitive style (heuristic/analytic), risk attitude, and previous computer experience as determined by a battery of pre-tests and questionnaires. In analyzinq the results, it was found that experience level was the dcminatinq factor on all dimensions: novices were slower, finished less frequently, and were siqnificantly less confident than experienced players. A hiqhly structured proqram interface was found to be more appropriate for these new users., Experience was also the dominating factor in the use of reports, although novices did show a marked learning effect over time - as did all users on most dimensions of performance and behaviour. As previously hypothesized, analytic-types and risk-takers played significantly faster and were more confident than heuristic-types and risk-averters, respectively. Concerning utilization of special program features, it was found that input response defaults influenced users in unfamiliar situations (ones which were new or did not have clear-cut responses), and didn't affect them at all in familiar circumstances. Analytic-types made least use of defaults. Bisk-averters were least likely to abbreviate commands. Also, the extent to which commands were abbreviated depended much upon their length, Finally, in the area of solution protocols, it was indeed found that heuristic-types were much less structured in their approach to solving the problem than analytic-types. . / Business, Sauder School of / Graduate

Today, ranking is the de facto way that information is presented to users in automated systems, which are increasingly used for high stakes decision making. Such ranking algorithms are typically opaque, and users don’t have control over the ranking process. When complex datasets are distilled into simple rankings, patterns in the data are exploited which may not reflect the user’s true preferences, and can even include subtle encodings of historical inequalities. Therefore it is paramount that the user’s preferences and fairness objectives are reflected in the rankings generated. This research addresses concerns around fairness and usability of ranking algorithms. The dissertation is organized in two parts. Part one investigates the usability of interactive systems for automatic ranking. The aim is to better understand how to capture user knowledge through interaction design, and empower users to generate personalized rankings. A detailed requirements analysis for interactive ranking systems is conducted. Then alternative preference elicitation techniques are evaluated in a crowdsourced user study. The study reveals surprising ways in which collection interfaces may prompt users to organize more data, thereby requiring minimal effort to create sufficient training data for the underlying machine learning algorithm. Following from these insights, RanKit is presented. This system for personalized ranking automatically generates rankings based on user-specified preferences among a subset of items. Explanatory features give feedback on the impact of user preferences on the ranking model and confidence of predictions. A case study demonstrates the utility of this interactive tool. In part two, metrics for evaluating the fairness of rankings are studied in depth, and a new problem of fair ranking by consensus is introduced. Three group fairness metrics are presented: rank equality, rank calibration, and rank parity which cover a broad spectrum of fairness considerations from proportional representation to error rate similarity across groups. These metrics are designed using a pairwise evaluation strategy to adapt algorithmic fairness concepts previously only applicable for classification. The metrics are employed in the FARE framework, a novel diagnostic tool for auditing rankings which exposes tradeoffs between different notions of fairness. Next, different ways of measuring a single definition of fairness are evaluated in a comparative study of state-of-the-art statistical parity metrics for ranking. This study identifies a core set of parity metrics which all behave similarly with respect to group advantage, reflecting well an intuitive definition of unfairness. However, this analysis also reveals that under relaxed assumptions about group advantage, different ways of measuring group advantage yield different fairness results. Finally, I introduce a new problem of fair ranking by consensus among multiple decision makers. A family of algorithms are presented which solve this open problem of guaranteeing fairness for protected groups of candidates, while still producing a good aggregation of the base rankings. Exact solutions are presented as well as a method which guarantees fairness with minimal approximation error. Together, this research expands the utility of ranking algorithms to support fair decision making.

Since the preservation campaigns at Lee Tung Street, the Star Ferry Pier and the Queen's Pier that erupted in early to mid-2000s, Hong Kong participatory art has undertaken an increasingly proactive role in local spatial movements, which marks the organizational and strategical evolvements of this artistic category that differentiate it from earlier public and community art. While research initiatives after 2010 have identified regional geospatial politics as one major concern for local participatory art today, existing studies tend to take a contextual approach with main emphases on why art becomes involved in urban spatial struggles while rarely proceeding to investigate what strategies or modes of spatial practices have emerged from relevant projects and what implications they have on the material-social spaces of the city. This hesitation to forward an interpretive evaluation of the focused phenomenon stems from the absence of epistemological concreteness in participatory art theories and criticisms, which necessitates the introduction of new analytical tools in research on the subject. To answer the pending questions, this research employs Henry Lefebvre's theories of the social production of space to examine three representative projects selected from a preliminary survey of local participatory art programs/groups which involve spatial practices. In exploring the contents, strategies, and socio-spatial implications of these cases, it presents three models of spatially oriented participatory art. On this basis, a cross-case analysis is conducted to explore how participatory art in general offers counterforces against the neoliberalist social-material and aesthetic reprogramming of the city while laying the social foundation for the anticipated production of differential spaces. As more urban renewal and land resumption plans are anticipated to storm through the city in the coming decades, this research hopes to provide for practitioners, researchers, and local communities the discursive and conceptual tools to understand the role of art in preceding and future spatial contestations

This thesis examines the unique representation of death in independent videogames. Specifically, in three titles: That Dragon, Cancer, Spiritfarer, and A Mortician's Tale. These three games break traditional norms of death in video games and how death is presented in other more traditional mediums. These unique perspectives are more concerned with the personal and societal side of death, the reflection, and confrontation of our mortality. Each game is a stand-out example of a growing trend in independent titles coined as "death positive" games. These types of games are made with the intent to approach death differently, potentially providing comfort to those struggling with death fear and anxiety. Through a close play of each game, analyzing their developer's design intentions and how they were received by audiences, I am to illustrate how independent games have become an ideal space to confront and manage death fear and anxiety. This is achieved through their unique ability to occupy a moment in ludic space and time, where a player can rest, reflect, and give up – an experience I call meaningful death reflection. This thesis offers a meaningful look at a potentially growing trend in various forms of media to present the topic of death in new contexts, distancing itself from traditional presentations in mainstream Western media. This trend would appear to be filling an audience's desire to engage with content that allows them the opportunity to think about their mortality in new ways.

Inhabitance is a Digital Interactive Installation employing the use of projection design, sound design, infrared depth mapping, and complex programming in the languages Processing and Java, in order to create an experiential work that leaves a lasting impact on both participants and the work itself. At it’s core, Inhabitance is about spatial and sensory presence. Taking distinct inspiration from other interactive projection works such as Snow Fall (2009) by Italian media studio FUSE°, and Text Rain (1995) by Camille Utterback and Romy Achituv, Inhabitance encourages participants to allow the boundary between their physical bodies and digital representations to blur. Participants who enter the active area of the installation are greeted with a white silhouette of themselves in a sea of letters. These letters, as they will soon discover, are not stationary. They react and interact with the movements made within the active area of the installation. Similarly to how participants in Text Rain soon begin to experiment with the interaction with the text, those in Inhabitance begin to “play” and test the rules of this newfound sensory environment. However, there is one more layer of interaction to be discovered. As soon as a letter moves, it creates a sound. Another is added to the space when another letter is moved. Each interactive object on the screen fills the space with sound, allowing participants to orchestrate their own accompaniment to the space. As those inside come to allow the boundary between physical and digital to blur, they now also begin the process of blurring the boundary between sight and sound. Reminiscent of Synesthesia (the condition where one sense triggers the experience of a different sense, such as sound triggering a sense of touch), the blurring of senses allows participants to experience a sense of “diminished consciousness of self”, and create an audiovisual experience totally unique to them. These letters and sounds will continue long after the participants have left the space, allowing messages, chords, or any other lasting impression to be passed onto those that will come next. Each new participant’s experience is a fully unique version, informed by those that have come before. “Under the hood” of Inhabitance is a complex marriage of software and hardware. Kinect cameras create an accurate depth map of the space, and feed their findings directly into Processing. Processing, with the help of libraries crafted by Daniel Schiffman, takes the Kinect information and uses that to draw a silhouette of any participants in a specific range. The letters and sounds are also handled by Processing, but without the use of a pre-built library. The letter objects, sonic interaction, and collision have all been coded by hand and are specific to the use-case of Inhabitance. / Theater / Film and Media Arts / Accompanied by two files: 1) Spratlin-Thesis-2023.pdf, 2) Inhabitance.zip / Accompanied by two files: 1) Spratlin-Thesis-2023.pdf, 2) Inhabitance.zip

Dimension reduction (DRs) are significant in data analysis to reduce the complexity of high dimensional data while preserving information to the greatest extent. However, the complex processes involved in DRs attribute to their inability to reason the relationship between the projection and the original data features (dimensions). "Why points are clustered?" and "What feature/s caused the points to scatter?" are some of the common questions. As a solution, we use gradients of the projection to generate visual explanations of the DRs. Utilizing these gradients, we show the point-wise sensitivities of the projection with respect to the original data features to explain the reasoning of DR. The combination of the gra- dients with various visualization techniques contribute to the exploration of the impact of dimensions on the projection. To overcome the curse of dimensionality, we propose inter- active techniques that facilitate the combination and comparison of features impact on the projection through gradients. Encapsulating the gradients and the visualization techniques, we present a web-based framework that facilitates an overview of impacts of all features and allows users to selectively explore notable features. / Master of Science / Data is prevalent in almost every facets of our lives. A simple data may comprise a few rows and couple of columns. Such data can be easily visualized and understood through simple visualization tools such as charts and graphs. However the real world data consists of large number of rows and columns (features, dimensions). As the number of features increase, so does the complexity to visualize and understand the data. One of the methods to reduce the high dimension data to low dimension is the dimension reduction (DR). DR methods generate a simpler form of data usually in 2D format which can be easily understood by human eyes. Even though the result from DR is simple, the complex process involved in the reduction of dimension makes the result (projection) difficult to understand. To better understand this projection, we propose visualization techniques that allow users to simulate change in original features and visualize the corresponding change in the projection.

published_or_final_version / Education / Doctoral / Doctor of Philosophy

The United States is in an emerging period of transition, shifting to online multimedia campaigns. This research attempts to explore general knowledge of multimedia expansion, and through qualitative research methods provide a successful model for the development of an effective promotion tool. Findings from the heuristic study showed users preferences for varying forms of media, thus demonstrating the need to provide content in many different forms. The findings from this study aide in the development of multimedia, and illustrate the need for further studies in the use of multimedia as a promotion tool. / Department of Telecommunications

by Chan Hung-Chin, Fu Lai-Yan, Carmen. / Thesis (M.B.A.)--Chinese University of Hong Kong, 1999. / Includes bibliographical references (leaves 47-50). / APPROVAL --- p.ii / ABSTRACT --- p.iii / TABLE OF CONTENTS --- p.iv / LIST OF ILLUSTRATIONS --- p.vi / LIST OF TABLES --- p.vii / ACKNOWLEDGMENTS --- p.viii / Chapter CHAPTER 1 - --- INTRODUCTION --- p.1 / Chapter 1.1 --- Main Theme --- p.2 / Chapter 1.2 --- Objective --- p.2 / Chapter 1.3 --- Methodology --- p.3 / Chapter 1.3.1 --- Interview --- p.3 / Chapter 1.3.2 --- Primary Data --- p.3 / Chapter 1.3.3 --- Secondary Data --- p.3 / Chapter 1.4 --- Report Structure --- p.4 / Chapter CHAPTER 2 - --- CASE DESCRIPTION --- p.5 / Chapter 2.1 --- What is Interactive Television? --- p.5 / Chapter 2.1.1 --- Potential Applications --- p.6 / Chapter 2.1.2 --- Value Chain --- p.7 / Chapter 2.2 --- Hongkong Telecom and iTV --- p.8 / Chapter 2.2.1 --- Company Background --- p.8 / Chapter 2.2.2 --- Why Developing i TV? --- p.8 / Chapter 2.3 --- Launching iTV in Hong Kong' --- p.10 / Chapter 2.3.1 --- Target Market --- p.10 / Chapter 2.3.2 --- Branding and Positioning --- p.10 / Chapter 2.3.3 --- Marketing Objectives --- p.11 / Chapter 2.3.4 --- Marketing Plan --- p.11 / Chapter 2.4 --- Current Situation --- p.12 / Chapter 2.4.1 --- Today's iTV --- p.13 / Chapter 2.4.2 --- Challenges --- p.14 / Chapter CHAPTER 3 - --- FOCUS GROUP INTERVIEWS --- p.18 / Chapter 3.1 --- Rationales of Using Focus Group Interviews --- p.18 / Chapter 3.2 --- Sample --- p.19 / Chapter 3.3 --- Specific Question Areas --- p.19 / Chapter 3.4 --- Summary of Findings --- p.21 / Chapter 3.5 --- Limitations --- p.25 / Chapter CHAPTER 4 - --- CASE ANALYSIS ……… --- p.27 / Chapter 4.1 --- Consumer Analysis --- p.27 / Chapter 4.2 --- 5Ps Analysis --- p.28 / Chapter 4.2.1 --- Product --- p.28 / Chapter 4.2.2 --- Price --- p.31 / Chapter 4.2.3 --- Promotion --- p.32 / Chapter 4.2.4 --- Place --- p.33 / Chapter 4.2.5 --- Personnel --- p.34 / Chapter 4.3 --- Factors Affecting Adoption Rate --- p.34 / Chapter 4.3.1 --- Relative Advantage --- p.34 / Chapter 4.3.2 --- Compatibility --- p.35 / Chapter 4.3.3 --- Complexity --- p.35 / Chapter 4.3.4 --- Trialability --- p.36 / Chapter 4.3.5 --- Observability --- p.36 / Chapter CHAPTER 5 - --- RECOMMENDATIONS --- p.37 / Chapter 5.1 --- Corporate-level Strategies --- p.37 / Chapter 5.2 --- Business-level Strategies --- p.38 / Chapter CHAPTER 6 - --- CONCLUSION --- p.40 / APPENDIX 1 --- p.41 / APPENDIX 2 --- p.42 / APPENDIX 3 --- p.43 / APPENDIX 4 --- p.44 / APPENDIX 5 --- p.45 / APPENDIX 6 --- p.46 / BIBLIOGRAPHY --- p.47