Righting Web Development

The web browser is the most important application runtime today, encompassing all types of applications on practically every Internet-connected device. Browsers power complete office suites, media players, games, and augmented and virtual reality experiences, and they integrate with cameras, microphones, GPSes, and other sensors available on computing devices. Many apparently native mobile and desktop applications are secretly hybrid apps that contain a mix of native and browser code. History has shown that when new devices, sensors, and experiences appear on the market, the browser will evolve to support them. Despite the browser\u27s importance, developing web applications is exceedingly difficult. Web browsers organically evolved from a document viewer into a ubiquitous program runtime. The browser\u27s scripting language for web designers, JavaScript, has grown into the only universally supported programming language in the browser. Unfortunately, JavaScript is notoriously difficult to write and debug. The browser\u27s high-level and event-driven I/O interfaces make it easy to add simple interactions to webpages, but these same interfaces lead to nondeterministic bugs and performance issues in larger applications. These bugs are challenging for developers to reason about and fix. This dissertation revisits web development and provides developers with a complete set of development tools with full support for the browser environment. McFly is the first time-traveling debugger for the browser, and lets developers debug web applications and their visual state during time-travel; components of this work shipped in Microsoft\u27s ChakraCore JavaScript engine. BLeak is the first system for automatically debugging memory leaks in web applications, and provides developers with a ranked list of memory leaks along with the source code responsible for them. BCause constructs a causal graph of a web application\u27s events, which helps developers understand their code\u27s behavior. Doppio lets developers run code written in conventional languages in the browser, and Browsix brings Unix into the browser to enable unmodified programs expecting a Unix-like environment to run directly in the browser. Together, these five systems form a solid foundation for web development

Improving User Involvement Through Live Collaborative Creation

Creating an artifact - such as writing a book, developing software, or performing a piece of music - is often limited to those with domain-specific experience or training. As a consequence, effectively involving non-expert end users in such creative processes is challenging. This work explores how computational systems can facilitate collaboration, communication, and participation in the context of involving users in the process of creating artifacts while mitigating the challenges inherent to such processes. In particular, the interactive systems presented in this work support live collaborative creation, in which artifact users collaboratively participate in the artifact creation process with creators in real time. In the systems that I have created, I explored liveness, the extent to which the process of creating artifacts and the state of the artifacts are immediately and continuously perceptible, for applications such as programming, writing, music performance, and UI design. Liveness helps preserve natural expressivity, supports real-time communication, and facilitates participation in the creative process. Live collaboration is beneficial for users and creators alike: making the process of creation visible encourages users to engage in the process and better understand the final artifact. Additionally, creators can receive immediate feedback in a continuous, closed loop with users. Through these interactive systems, non-expert participants help create such artifacts as GUI prototypes, software, and musical performances. This dissertation explores three topics: (1) the challenges inherent to collaborative creation in live settings, and computational tools that address them; (2) methods for reducing the barriers of entry to live collaboration; and (3) approaches to preserving liveness in the creative process, affording creators more expressivity in making artifacts and affording users access to information traditionally only available in real-time processes. In this work, I showed that enabling collaborative, expressive, and live interactions in computational systems allow the broader population to take part in various creative practices.PHDComputer Science & EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttps://deepblue.lib.umich.edu/bitstream/2027.42/145810/1/snaglee_1.pd

Synchronous Internet Distance Education: Wave of the Future or Wishful Thinking?

Heralded as an important future delivery means for higher education, synchronous Internet distance education with live presenters is, to date, far less often used than its counterpart asynchronous distance education which offers materials stored on a website. The author has practiced synchronous Internet teaching since 1994 at George Mason University (GMU). This practice now is increasing, with a doubling of GMU Computer Science courses taught this way each year for the past three. This paper describes the lessons learned in finding a successful way to teach synchronous over the Internet. Technologies and class organization needed for success are described and compared. The results appear to indicate that synchronous Internet distance education may in fact become an important future delivery means for higher education

Doctor of Philosophy

dissertationA modern software system is a composition of parts that are themselves highly complex: operating systems, middleware, libraries, servers, and so on. In principle, compositionality of interfaces means that we can understand any given module independently of the internal workings of other parts. In practice, however, abstractions are leaky, and with every generation, modern software systems grow in complexity. Traditional ways of understanding failures, explaining anomalous executions, and analyzing performance are reaching their limits in the face of emergent behavior, unrepeatability, cross-component execution, software aging, and adversarial changes to the system at run time. Deterministic systems analysis has a potential to change the way we analyze and debug software systems. Recorded once, the execution of the system becomes an independent artifact, which can be analyzed offline. The availability of the complete system state, the guaranteed behavior of re-execution, and the absence of limitations on the run-time complexity of analysis collectively enable the deep, iterative, and automatic exploration of the dynamic properties of the system. This work creates a foundation for making deterministic replay a ubiquitous system analysis tool. It defines design and engineering principles for building fast and practical replay machines capable of capturing complete execution of the entire operating system with an overhead of several percents, on a realistic workload, and with minimal installation costs. To enable an intuitive interface of constructing replay analysis tools, this work implements a powerful virtual machine introspection layer that enables an analysis algorithm to be programmed against the state of the recorded system through familiar terms of source-level variable and type names. To support performance analysis, the replay engine provides a faithful performance model of the original execution during replay

An All-in-One Debugging Approach: Java Debugging, Execution Visualization and Verification

We devise a widely applicable debugging approach to deal with the prevailing issue that bugs cannot be precisely reproduced in nondeterministic complex concurrent programs. A distinct efficient record-and-playback mechanism is designed to record all the internal states of execution including intermediate results by injecting our own bytecode, which does not affect the source code, and, through a two-step data processing mechanism, these data will be aggregated, structured and parallel processed for the purpose of replay in high fidelity while keeping the overhead at a satisfactory level. Docker and Git are employed to create a clean environment such that the execution will be undertaken repeatedly with a maximum precision of reproducing bugs. In our development, several other forefront technologies, such as MongoDB, Spark and Node.js are utilized and smoothly integrated for easy implementation. Altogether, we develop a system for Java Debugging Execution Visualization and Verification (JDevv), a debugging tool for Java although our debugging approach can apply to other languages as well. JDevv also offers an aggregated and interactive visualization for the ease of users’ code verification

On-Demand Collaboration in Programming

In programming, on-demand assistance occurs when developers seek support for their tasks as needed. Traditionally, this collaboration happens within teams and organizations in which people are familiar with the context of requests and tasks. More recently, this type of collaboration has become ubiquitous outside of teams and organizations, due to the success of paid online crowdsourcing marketplaces (e.g., Upwork) and free online question-answering websites (e.g., Stack Overflow). Thousands of requests are posted on these platforms on a daily basis, and many of them are not addressed in a timely manner for a variety of reasons, including requests that often lack sufficient context and access to relevant artifacts. In consequence, on-demand collaboration often results in suboptimal productivity and unsatisfactory user experiences. This dissertation includes three main parts: First, I explored the challenges developers face when requesting help from or providing assistance to others on demand. I have found seven common types of requests (e.g., seeking code examples) that developers use in various projects when an on-demand agent is available. Compared to studying existing supporting systems, I suggest eight key system features to enable more effective on-demand remote assistance for developers. Second, driven by these findings, I designed and developed two systems: 1) CodeOn, a system that enables more effective task hand-offs (e.g., rich context capturing) between end-user developers and remote helpers than exciting synchronous support systems by allowing asynchronous responses to on-demand requests; and 2) CoCapture, a system that enables interface designers to easily create and then accurately describe UI behavior mockups, including changes they want to propose or questions they want to ask about an aspect of the existing UI. Third, beyond software development assistance, I also studied intelligent assistance for embedded system development (e.g., Arduino) and revealed six challenges (e.g., communication setup remains tedious) that developers have during on-demand collaboration. Through an imaginary study, I propose four design implications to help develop future support systems with embedded system development. This thesis envisions a future in which developers in all kinds of domains can effortlessly make context-rich, on-demand requests at any stage of their development processes, and qualified agents (machine or human) can quickly be notified and orchestrate their efforts to promptly respond to the requests.PHDInformationUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/166144/1/yanchenm_1.pd

Attorneys\u27 Experiences with Continuing Legal Education Delivered Online: A Holistic Single Case Study

The purpose of this qualitative holistic single case study was to describe how practicing attorneys in North Carolina experience continuing legal education (CLE) courses delivered online. The theories guiding the study are Knowles’ adult learning theory and Siemens’ connectivist theory, as they address how adults learn and how the use of technology connects learning. The central research question is as follows: How do practicing attorneys in North Carolina experience online CLE courses? This question leads to three sub-questions: What meaning do practicing attorneys ascribe to CLE? What benefits and concerns do attorneys identify with CLE delivered online? How do attorneys connect CLE content to their legal practice? The literature review presents what is known about the guiding theories, professional development, CLE, and online learning for adults. The gap in the literature is a lack of information regarding the experience with professional development delivered online for attorneys. Results of the study show that the attorney experience with online CLE is ineffective, with little transfer to the practice of law

A Web-Based Collaborative Multimedia Presentation Document System

With the distributed and rapidly increasing volume of data and expeditious development of modern web browsers, web browsers have become a possible legitimate vehicle for remote interactive multimedia presentation and collaboration, especially for geographically dispersed teams. To our knowledge, although there are a large number of applications developed for these purposes, there are some drawbacks in prior work including the lack of interactive controls of presentation flows, general-purpose collaboration support on multimedia, and efficient and precise replay of presentations. To fill the research gaps in prior work, in this dissertation, we propose a web-based multimedia collaborative presentation document system, which models a presentation as media resources together with a stream of media events, attached to associated media objects. It represents presentation flows and collaboration actions in events, implements temporal and spatial scheduling on multimedia objects, and supports real-time interactive control of the predefined schedules. As all events are represented by simple messages with an object-prioritized approach, our platform can also support fine-grained precise replay of presentations. Hundreds of kilobytes could be enough to store the events in a collaborative presentation session for accurate replays, compared with hundreds of megabytes in screen recording tools with a pixel-based replay mechanism