Real-time analytics on large dynamic graphs

In today's fast-paced and interconnected digital world, the data generated by an increasing number of applications is being modeled as dynamic graphs. The graph structure encodes relationships among data items, while the structural changes to the graphs as well as the continuous stream of information produced by the entities in these graphs make them dynamic in nature. Examples include social networks where users post status updates, images, videos, etc.; phone call networks where nodes may send text messages or place phone calls; road traffic networks where the traffic behavior of the road segments changes constantly, and so on. There is a tremendous value in storing, managing, and analyzing such dynamic graphs and deriving meaningful insights in real-time. However, a majority of the work in graph analytics assumes a static setting, and there is a lack of systematic study of the various dynamic scenarios, the complexity they impose on the analysis tasks, and the challenges in building efficient systems that can support such tasks at a large scale. In this dissertation, I design a unified streaming graph data management framework, and develop prototype systems to support increasingly complex tasks on dynamic graphs. In the first part, I focus on the management and querying of distributed graph data. I develop a hybrid replication policy that monitors the read-write frequencies of the nodes to decide dynamically what data to replicate, and whether to do eager or lazy replication in order to minimize network communication and support low-latency querying. In the second part, I study parallel execution of continuous neighborhood-driven aggregates, where each node aggregates the information generated in its neighborhoods. I build my system around the notion of an aggregation overlay graph, a pre-compiled data structure that enables sharing of partial aggregates across different queries, and also allows partial pre-computation of the aggregates to minimize the query latencies and increase throughput. Finally, I extend the framework to support continuous detection and analysis of activity-based subgraphs, where subgraphs could be specified using both graph structure as well as activity conditions on the nodes. The query specification tasks in my system are expressed using a set of active structural primitives, which allows the query evaluator to use a set of novel optimization techniques, thereby achieving high throughput. Overall, in this dissertation, I define and investigate a set of novel tasks on dynamic graphs, design scalable optimization techniques, build prototype systems, and show the effectiveness of the proposed techniques through extensive evaluation using large-scale real and synthetic datasets.

OVERCOMING INTERCULTURAL CHALLENGES IN INTERPRETING: A CASE STUDY ON CHINESE-ENGLISH CONFERENCE INTERPRETING

This exploratory case study examines the role of culture in Chinese-English conference interpreting. Given that there has been a lack of empirical research in understanding the role of culture in conference interpreting through the lens of intercultural communication frameworks, we know relatively little about conference interpreters’ experiences with intercultural communication challenges. This project helps address this research gap by investigating the types of intercultural communication challenges that Chinese-English conference interpreters experience and their strategies in managing those challenges. This study hears the voices of both professionals and postgraduate interpreting students. A total number of 27 participants were recruited for this research. Twenty professional conference interpreter were interviewed and seven interpreting students were organized for a focus group discussion. Grounded theory was used to analyze the participants’ observations and strategies in managing intercultural communication challenges when doing Chinese-English conference interpreting. The data analysis process led to the emergence of two procedural guidelines and one process – Interpreters’ Intercultural Mediation Process. The two procedural guidelines offer guidance for the interpreters to provide the most appropriate and effective service: meet with the clients beforehand and be prepared to offer intercultural insights when consulted. Interpreters are found to follow the Interpreters’ Intercultural Mediation Process to decide when and how to mediate intercultural communication challenges at work. This Process includes four criteria, seven intercultural challenges, and seven coping strategies. This study offers theoretical and applied contributions to our understanding of the role of culture in interpreting. By jointly applying frameworks from intercultural communication and interpreting studies to examine the conference interpreting process, this case study makes great efforts to connect the field of intercultural communication with the field of interpreting studies. This study identifies the types of intercultural differences that would lead to challenges in Chinese-English conference interpreting. It also contributes to the call for a cultural turn in interpreting studies. By learning the two procedural guidelines, conference interpreters can be better prepared for their work. By following the Interpreters’ Intercultural Mediation Process, conference interpreters can better anticipate and manage the intercultural challenges at work. This study also offers guidance on tailoring intercultural communication courses for postgraduate interpreting training programs.

The Real-Quaternionic Indicator of Irreducible Self-Conjugate Representations of Real Reductive Algebraic Groups and A Comment on the Local Langlands Correspondence of GL(2, F )

The real-quaternionic indicator, also called the $\delta$ indicator, indicates if a self-conjugate representation is of real or quaternionic type. It is closely related to the Frobenius-Schur indicator, which we call the $\varepsilon$ indicator. The Frobenius-Schur indicator $\varepsilon(\pi)$ is known to be given by a particular value of the central character. We would like a similar result for the $\delta$ indicator. When $G$ is compact, $\delta(\pi)$ and $\varepsilon(\pi)$ coincide. In general, they are not necessarily the same. In this thesis, we will give a relation between the two indicators when $G$ is a real reductive algebraic group. This relation also leads to a formula for $\delta(\pi)$ in terms of the central character. For the second part, we consider the construction of the local Langlands correspondence of $GL(2,F)$ when $F$ is a non-Archimedean local field with odd residual characteristics. By re-examining the construction, we provide new proofs to some important properties of the correspondence. Namely, the construction is independent of the choice of additive character in the theta correspondence.