41810424
Feature Interaction Problems in Middleware Services
15430727
Towards Service Discovery and Subscription based on Community-of-Interest
Current service discovery and subscription are "provider-centric " indeed, which costs the consumers too many efforts and makes the wide spectrum of QoS hard to use. In this position paper, we propose a "consumer-centric" service discovery and subscription approach. The core idea is derived from the "community-of-interest (CoI)" concept, which means the services with same or similar functionalities can form a community of the consumer's interest. This approach facilitates the consumers in three ways. Firstly, it simplifies the service discovery for the consumers who can "purely" care about the functionality and qualities instead of the providers. Secondly, it optimizes the service subscription for the consumers who just subscribe the CoI instead of a single and monolithic service provider while the COI takes charge of matching and scheduling the "best-of-breed" service automatically. Thirdly, it incarnates the wide spectrum of QoS to the consumers who will face with all possible QoS supported by the services in the CoI. The supporting framework is discussed and some key technical issues are demonstrated
3127291
Repository synchronization in the OAI framework
The Open Archives Initiative Protocol for Metadata Harvesting (OAI-PMH) began as an alternative to distributed searching of scholarly e-print repositories. The model embraced by the OAI-PMH is that of metadata harvesting, where value-added services (by a "service provider") are constructed on cached copies of the metadata extracted from the repositories of the harvester's choosing. While this model dispenses with the well-known problems of distributed searching, it introduces the problem of synchronization. Stated simply, this problem arises when the service provider's copy of the metadata does not match the metadata currently at the constituent repositories. We define some metrics for describing the synchronization problem in the OAI-PMH. Based on these metrics, we study the synchronization problem of the OAI-PMH framework and propose several approaches for harvesters to implement better synchronization. In particular, if a repository knows its update frequency, it can publish it in an OAI-PMH identify response using an optional about container that borrows from RDF Site Syndication (RSS) Format.
893749
A Distributed and Efficient Flooding Scheme Using 1-Hop Information in Mobile Ad Hoc Networks
Flooding is one of the most fundamental operations in mobile ad hoc networks. Traditional implementation of flooding suffers from the problems of excessive redundancy of messages, resource contention, and signal collision. This causes high protocol overhead and interference with the existing traffic in the networks. Some efficient flooding algorithms were proposed to avoid these problems. However, these algorithms either perform poorly in reducing redundant transmissions or require each node to maintain 2-hop (or more) neighbors information. In the paper, we study the sufficient and necessary condition of 100 percent deliverability for flooding schemes that are based on only 1-hop neighbors information. We further propose an efficient flooding algorithm that achieves the local optimality in two senses: 1) the number of forwarding nodes in each step is minimal and 2) the time complexity for computing forwarding nodes is the lowest, which is O(nlogn), where n is the number of neighbors of a node. Extensive simulations have been conducted and simulation results have shown the excellent performance of our algorithm
1063503
Mutual anonymous overlay multicast
Multicast services are demanded by a variety of applications. Many applications require anonymity during their communication. However, there has been very little work on anonymous multicasting and such services are not available yet. Due to the fundamental differences between multicast and unicast, the solutions proposed for anonymity in unicast communications cannot be directly applied to multicast applications. In this paper we define the anonymous multicast system, and propose a mutual anonymous multicast (MAM) protocol including the design of a unicast mutual anonymity protocol and construction and optimization of an anonymous multicast tree. MAM is self-organizing and completely distributed. We define the attack model in an anonymous multicast system and analyze the anonymity degree. We also evaluate the performance of MAM by comprehensive simulations.
353647
On Estimating Tight-Link Bandwidth Characteristics over Multi-Hop Paths
In this paper, we explore multi-hop bandwidth estimation assuming arbitrary cross-traffic at each node and develop a new probing method called Envelope that can asymptotically estimate not only the available bandwidth but also the raw capacity of the tight link. Envelope is based on a multi-link recursive extension of unbiased single-hop estimators proposed in the past (e.g., [14]) and a variation of the packet-cartouche technique [6]. Through extensive simulations, we evaluate Envelope in various network settings and cross-traffic conditions and find that it can measure tight-link bandwidth characteristics with accuracy that significantly surpasses that of the existing methods. We also find that Envelope can measure non-tight links in certain path and cross-traffic configurations.
65741
WebDG - A Platform for E-Government Web Services
Web services are deemed as the natural choice for deploying e-government applications. Their use enables e-government to fully get advantage of the envisioned Semantic Web. In this paper, we propose WebDG, a comprehensive Web Service Management System for e-government applications. It aims to improve government-citizen interactions through an infrastructure built around the ”life experience” of citizens. WebDG provides a framework for automatically composing e-government services, optimized querying services, and preserving privacy.