Wu Chou

Hyperlink Pipeline: Lightweight Service Composition for Users

This paper describes a lightweight service composition mechanism in web browsers, called hyperlink pipeline, to allow users to interactively chain distributed atomic web services into composite services similar to using Unix pipelines. This mechanism addresses the limitation in current Web, which confines users to following predefined hyperlinks and forms. We present the functional composition framework to facilitate recursive hyperlink pipeline construction and execution based on REST services and the HTML5 Micro data model to efficiently implement the framework. The proposed mechanism has been implemented and used in several web applications for real-time communication and collaboration based on WebRTC. The initial tests indicate the approach is feasible and promising.

Mirror Presence: Secure Web Identity Resolution and Call Control for WebRTC

Identity resolution is a critical component in any real-time communication system, including WebRTC that relies on Web identities. The difficulty with Web identity resolution is that there is no uniform Web identity scheme and current Web identity schemes decouple Web identities and Web locations. To address this problem for WebRTC without introducing a central authority, we present a secure personal Web identity resolution framework, mirror presence, to dynamically map a users Web identity to Web locations while the user can move between Web locations. The system is agnostic to Web identity schemes, and it consists of 3 layers of Web protocols and services: 1) bilateral authorization based on OAuth 2.0; 2) Web identity binding based on presence subscription and notification; 3) presence driven call routing and pickup protocols. Each layer of the system can be controlled by users based on security, privacy, and personal preferences. A prototype mirror presence system has been implemented, and experimental results indicated that the approach is feasible and the performance is satisfactory.

Compose Presence for Composite Web Services by Timed AND-OR Tree

Both presence and web service composition are very important to web based real-time communication systems. Although there is some work to combine presence with individual web services, there still lacks an efficient presence composition method to determine presence for composite web services, which is a collection of web services arranged by a process. This paper proposes a distributed computation model, called TAO-Tree (Timed AND-OR tree) to map discrete presence states to continuous time domain such that presence compositions can be carried recursively by arithmetic operations. Furthermore, the paper describes a method to translate the presence delays back to discrete presence states with minimal errors. We implement the TAO-Tree module in a prototype system and the experiments show the approach is feasible and satisfactory.