Real-time collaborative coding in a web IDE

This paper describes Collabode, a web-based Java integrated development environment designed to support close, synchronous collaboration between programmers. We examine the problem of collaborative coding in the face of program compilation errors introduced by other users which make collaboration more difficult, and describe an algorithm for error-mediated integration of program code. Concurrent editors see the text of changes made by collaborators, but the errors reported in their view are based only on their own changes. Editors may run the program at any time, using only error-free edits supplied so far, and ignoring incomplete or otherwise error-generating changes. We evaluate this algorithm and interface on recorded data from previous pilot experiments with Collabode, and via a user study with student and professional programmers. We conclude that it offers appreciable benefits over naive continuous synchronization without regard to errors and over manual version control.National Science Foundation (U.S.) (award IIS- 0447800

Programming with human computation

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2011.Cataloged from PDF version of thesis.Includes bibliographical references (p. 151-156).Amazon's Mechanical Turk provides a programmatically accessible micro-task market, allowing a program to hire human workers. This has opened the door to a rich field of research in human computation where programs orchestrate the efforts of humans to help solve problems. This thesis explores challenges that programmers face in this space: both technical challenges like managing high-latency, as well as psychological challenges like designing effective interfaces for human workers. We offer tools and experiments to overcome these challenges in an effort to help future researchers better understand and harness the power of human computation. The main tool this thesis offers is the crash-and-rerun programming model for managing high-latency tasks on MTurk, along with the TurKit toolkit which implements crash-and-rerun. TurKit provides a straightforward imperative programming environment where MTurk is abstracted as a function call. Based on our experience using TurKit, we propose a simple model of human computation algorithms involving creation and decision tasks. These tasks suggest two natural workflows: iterative and parallel, where iterative tasks build on each other and parallel tasks do not. We run a series of experiments comparing the merits of each workflow, where iteration appears to increase quality, but has limitations like reducing the variety of responses and getting stuck in local maxima. Next we build a larger system composed of several iterative and parallel workflows to solve a real world problem, that of transcribing medical forms, and report our experience. The thesis ends with a discussion of the current state-of-the-art of human computation, and suggests directions for future work.by Greg Little.Ph.D

Programming with keywords

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2007.Includes bibliographical references (p. 105-108).Modern applications provide interfaces for scripting, but many users do not know how to write script commands. However, many users are familiar with the idea of entering keywords into a web search engine. Hence, if a user is familiar with the vocabulary of an application domain, they may be able to write a set of keywords expressing a command in that domain. For instance, in the web browsing domain, a user might enter the keywords click search button. This thesis presents several algorithms for translating keyword queries such as this directly into code. A prototype of this system in the web browsing domain translates click search button into the code click(findButton("search")). This code may then be executed in the context of a web browser to carry out the effect. Another prototype in the Java domain translates append message to log into log.append(message), given an appropriate context of local variables and imported classes. The algorithms and prototypes are evaluated with several studies, suggesting that users can write keyword queries with little or no instructions, and that the resulting translations are often accurate. This is especially true in small domains like the web, whereas in a large domain like Java, the accuracy is comparable to the accuracy of writing syntactically correct Java code without assistance.by Greg Little.S.M

TurKit: Human Computation Algorithms on Mechanical Turk

Mechanical Turk (MTurk) provides an on-demand source of human computation. This provides a tremendous opportunity to explore algorithms which incorporate human computation as a function call. However, various systems challenges make this difficult in practice, and most uses of MTurk post large numbers of independent tasks. TurKit is a toolkit for prototyping and exploring algorithmic human computation, while maintaining a straight-forward imperative programming style. We present the crash-and-rerun programming model that makes TurKit possible, along with a variety of applications for human computation algorithms. We also present case studies of TurKit used for real experiments across different fields.Xerox CorporationNational Science Foundation (U.S.) (Grant No. IIS- 0447800)Quanta ComputerMassachusetts Institute of Technology. Center for Collective Intelligenc

Intravascular ultrasound scanning improves long-term patency of iliac lesions treated with balloon angioplasty and primary stenting

AbstractPurpose: Underdeployment of an intravascular stent has been identified as a cause of restenosis or occlusion of a treated arterial lesion. Intravascular ultrasound (IVUS) has been shown to initially improve the anatomic and clinical stenting. The purpose of this study was to determine whether the use of IVUS increased long-term patency of this intervention. Methods: Between March 1992 and October 1995, 71 limbs (52 patients) with symptomatic aortoiliac occlusive disease underwent balloon angioplasty with primary stenting. IVUS and arteriography were used in 49 limbs (36 patients) to evaluate stent deployment. Arteriography alone was used in 22 limbs (16 patients) to evaluate stent deployment. Patients were captured prospectively in a vascular registry and retrospectively reviewed. Results: Mean age of patients treated with IVUS was 61.1 ± 9.0 years (range, 38-85) versus 70.0 ± 10.1 years (range, 57-87) in patients treated without IVUS (P <.01). There was no difference between the groups with respect to preoperative comorbidities, ankle-brachial indices, or number of stents per limb. Mean follow-up for IVUS patients was 62.1 ± 7.3 months (range, 15-81) and 57.9 ± 8.7 months (range, 8-80) for patients treated without IVUS (P = not significant). In 40% (20/49) of limbs, IVUS demonstrated inadequate stent deployment at the time of the original procedure. Kaplan-Meier 3- and 6-year primary patency estimates were 100% and 100% in the IVUS group and 82% and 69%, respectively, in limbs treated without IVUS (P <.001). There have been no secondary procedures performed in limbs treated with IVUS and a 23% (5/22) secondary intervention rate in the non-IVUS group (P <.05). Overall Kaplan-Meier survival estimates at 3 and 6 years for all patients were 84% and 67%, respectively. Conclusion: Balloon angioplasty and primary stenting of symptomatic aortoiliac occlusive lesions is a durable treatment option. Long-term follow-up of treated patients shows outcomes that are comparable with direct surgical intervention. IVUS significantly improved the long-term patency of iliac arterial lesions treated with balloon angioplasty and stenting by defining the appropriate angioplasty diameter endpoint and adequacy of stent deployment. (J Vasc Surg 2002;35:316-23.

Soylent: A Word Processor with a Crowd Inside

This paper introduces architectural and interaction patterns for integrating crowdsourced human contributions directly into user interfaces. We focus on writing and editing, com-plex endeavors that span many levels of conceptual and pragmatic activity. Authoring tools offer help with prag-matics, but for higher-level help, writers commonly turn to other people. We thus present Soylent, a word processing interface that enables writers to call on Mechanical Turk workers to shorten, proofread, and otherwise edit parts of their documents on demand. To improve worker quality, we introduce the Find-Fix-Verify crowd programming pat-tern, which splits tasks into a series of generation and re-view stages. Evaluation studies demonstrate the feasibility of crowdsourced editing and investigate questions of relia-bility, cost, wait time, and work time for edits.National Science Foundation (U.S.) (Grant No. IIS-0712793

VizWiz

The lack of access to visual information like text labels, icons,and colors can cause frustration and decrease independence for blind people. Current access technology uses automatic approaches to address some problems in this space, but the technology is error-prone, limited in scope, and quite expensive. In this paper, we introduce VizWiz, a talking application for mobile phones that offers a new alternative to answering visual questions in nearly real-time—asking multiple people on the web. To support answering questions quickly, we introduce a general approach for intelligently recruiting human workers in advance called quikTurkit so that workers are available when new questions arrive. A field deployment with 11 blind participants illustrates that blind people can effectively use VizWiz to cheaply answer questions in their everyday lives, highlighting issues that automatic approaches will need to address to be useful. Finally, we illustrate the potential of using VizWiz as part of the participatory design of advanced tools by using it to build and evaluate VizWiz::LocateIt, an interactive mobile tool that helps blind people solve general visual search problems

Factors Influencing Consumption Behaviour towards Aquatic Food among Asian Consumers: A Systematic Scoping Review

Asia accounts for over 70% of total global aquatic food consumption, but aquatic food consumption behaviours and attitudes among Asian consumers are poorly documented and understood. This paper synthesises literature on factors influencing aquatic food consumption behaviour in Asia and the potential to support transitions toward more sustainable food consumption patterns. We identified 113 studies for inclusion in a scoping review, and identified five clusters of publications: (1) product attributes, availability, and accessibility (24% of publications); (2) willingness to pay for aquatic foods (25%); (3) psychosocial factors (e.g., attitudes and subjective norms) (17%); (4) sociodemographic and lifestyle factors (21%); and (5) miscellaneous factors, including food safety and social status (13%). This study indicates that multiple interacting factors influence aquatic food consumption behaviours among Asian consumers, among which price is central. Knowledge of, and attitudes toward, the perceived quality and safety of aquatic foods were identified as important but were mediated by household characteristics. Sustainable production practices, country of origin, and ecolabels were found to be less influential on consumption behaviour. We found that improving consumers’ knowledge and attitudes about the quality and safety of aquatic foods might positively influence aquatic food consumption behaviour. Future multidisciplinary research is required to better understand interactions among the multiple factors that influence Asian consumers’ aquatic food consumption behaviour

Differential regulation of genes for cyclic-di-GMP metabolism orchestrates adaptive changes during rhizosphere colonization by Pseudomonas fluorescens

Bacteria belonging to the Pseudomonas genus are highly successful colonizers of the plant rhizosphere. The ability of different Pseudomonas species to live either commensal lifestyles or to act as agents of plant-growth promotion or disease is reflected in a large, highly flexible accessory genome. Nevertheless, adaptation to the plant environment involves a commonality of phenotypic outputs such as changes to motility, coupled with synthesis of nutrient uptake systems, stress-response molecules and adherence factors including exopolysaccharides. Cyclic-di-GMP (cdG) is a highly important second messenger involved in the integration of environmental signals with appropriate adaptive responses and is known to play a central role in mediating effective rhizosphere colonization. In this study, we examined the transcription of multiple, reportedly plant-upregulated cdG metabolism genes during colonization of the wheat rhizosphere by the plant-growth-promoting strain P. fluorescens SBW25. While transcription of the tested genes generally increased in the rhizosphere environment, we additionally observed a tightly orchestrated response to environmental cues, with a distinct transcriptional pattern seen for each gene throughout the colonization process. Extensive phenotypical analysis of deletion and overexpression strains was then conducted and used to propose cellular functions for individual cdG signaling genes. Finally, in-depth genetic analysis of an important rhizosphere colonization regulator revealed a link between cdG control of growth, motility and stress response, and the carbon sources available in the rhizosphere

Trehalose and α-glucan mediate distinct abiotic stress responses in Pseudomonas aeruginosa

An important prelude to bacterial infection is the ability of a pathogen to survive independently of the host and to withstand environmental stress. The compatible solute trehalose has previously been connected with diverse abiotic stress tolerances, particularly osmotic shock. In this study, we combine molecular biology and biochemistry to dissect the trehalose metabolic network in the opportunistic human pathogen Pseudomonas aeruginosa PAO1 and define its role in abiotic stress protection. We show that trehalose metabolism in PAO1 is integrated with the biosynthesis of branched α-glucan (glycogen), with mutants in either biosynthetic pathway significantly compromised for survival on abiotic surfaces. While both trehalose and α-glucan are important for abiotic stress tolerance, we show they counter distinct stresses. Trehalose is important for the PAO1 osmotic stress response, with trehalose synthesis mutants displaying severely compromised growth in elevated salt conditions. However, trehalose does not contribute directly to the PAO1 desiccation response. Rather, desiccation tolerance is mediated directly by GlgE-derived α-glucan, with deletion of the glgE synthase gene compromising PAO1 survival in low humidity but having little effect on osmotic sensitivity. Desiccation tolerance is independent of trehalose concentration, marking a clear distinction between the roles of these two molecules in mediating responses to abiotic stress