Peter Lucas

JDA: a step towards large-scale reuse on the web

The Web is maturing as a rich application development platform, and efforts are being made to provide richer and more dynamic interactions using JavaScript. JavaScript-based Web applications such as Google Maps have gained extra attention because they can be easily included in HTML for reuse. Unfortunately, various technical hurdles have made it difficult for JavaScript reuse to extend beyond its current state. Furthermore, JavaScript reuse is still out of reach for a large portion of the Web user base unversed in the use of programming languages.In this paper, we dive deeper into our previous work on the JavaScript Dataflow Architecture (JDA). JDA is intended for Web client applications written using HTML and JavaScript. We discuss the ways in which the architecture addresses many of the hurdles that modern Web client applications face in the realm of large-scale reuse and remixing. JDA aims to provide an ecosystem comprised of black box components operating within a JavaScript-based asynchronous message-passing environment. The environment allows you to use simple HTML to assemble Web applications from JavaScript black boxes scattered around the World Wide Web. No programming skill is required in their assembly, and no plug-ins or applets are required for their execution. Furthermore, the architecture extends the black box metaphor beyond the boundaries of JavaScript and allows multiple JavaScript components contained within an HTML file to be reused as a whole.A detailed account of an early prototype is discussed, and research is being done to improve it. JDA suggests that large-scale reuse and arbitrary remixing of Web applications can be realized using currently existing technologies.

Managing distributed collaboration in a peer-to-peer network

Shared mutable information objects called u-forms provide an attractive foundation on which to build collaborative systems As we scale up such systems from small fully-connected workgroups to large, highly distributed, and partially disconnected groups, we have found that peer-to-peer technology and optimistic replication strategies provide a cost-effective mechanism for maintaining good performance Unfortunately, such systems present well-known coordination and consistency problems This paper discusses strategies for addressing those difficulties at different levels of the system design, focusing on providing solutions in the information architecture rather than at the infrastructure layer Addressing problems at this higher layer allows greater freedom in design, and simplifies moving from one infrastructural base to another as technology evolves Our primary strategy is to enable robust decentralized and asynchronous collaboration while designing architectures that do not rely on two users writing to the same u-form at the same time in different venues Techniques are provided for simple messaging, collaborative maintenance of collections, indexing supporting rich query, and stand-off annotation and elaboration of third-party datasets We outline the application of these techniques in a working collaborative system.

Shepherdable indexes and persistent search services for mobile users

We describe a range of designs for supporting rich search queries in a peer-to-peer network Our implementation is based upon uniquely identified data objects which are replicated upon request by agents called Shepherds Several abstract data structures are built upon this framework, supporting dataset management, lexical search, and distributed GIS interfaces in an application called the Geobrowser Our results demonstrate that it is possible to layer higher-level data structures upon a basic peer-to-peer transport and replication layer When users perform a given query, parts of the index as well as the query results themselves are shepherded to the users local venue A natural benefit of this approach is that mobile users can repeat previous searches if they become disconnected from the rest of the network Some of the data structures that prove to be successful are peer-to-peer adaptations of traditional indexing structures We review some of the properties that lead to successful designs in this domain, giving examples of deployed systems in the Geobrowser.

Successful visual and end-user programming systems from industry

Summary form only given. Above showsthat the next generation of mobile applications for MOPs need to be part of a much large mobile information system. Such system should be capable of receiving information from a large number of users, intelligently aggregating the information to useful, meaningful, real-time information and making them available to users. Users should be able to make queries and quickly find information that would enhance their day to day activities. It should also have the functionalities to detect different and unusual situations, provide alerts to users in unusual circumstances and emergencies so that users can respond accordingly. These next generation mobile applications for MOPs will open up a very large market currently estimated to be around 3 billion people [13]. These applications will empower them to be information users as well as information producers. Such applications would result in up lifting of economic conditions of the MOPs and transformation of social processes.

Scripting a radically-distributed world

The built world increasingly comprises objects with at least some information-processing capability, and these objects are rapidly acquiring the ability to intercommunicate. The problem of how to orchestrate huge numbers of independently designed devices into coherent environments is becoming acute. A pure dataflow programming paradigm is a natural choice for addressing this challenge. We present an information centric, recursive, hybrid visual programming environment that addresses many of the usability problems that have plagued previous attempts at large-scale visual dataflow programming environments.