6337639
Transparent sharing and interoperation of heterogeneous single-user applications
Multi-user applications generally lag behind in features or compatibility with single-user applications. As a result, users are often not motivated to abandon their favorite single-user applications for groupware features that are less frequently used. A well-accepted approach, collaboration transparency, is able to convert off-the-shelf single-user applications into groupware without modifying the source code. However, existing systems have been largely striving to develop generic application-sharing mechanisms and undesirably force users to share the same application in cooperative work. In this paper we analyze this problem and present a novel approach (called intelligent collaboration transparency) to addressing this problem. Our approach allows for heterogeneous application sharing by considering the particular semantics of the applications and the collaboration task in question.
274260
Preserving operation effects relation in group editors
Consistency maintenance is a critical and challenging issue in many interactive groupware applications that can be modeled as group editors. This paper addresses two open consistency problems: divergence and operation effects relation violation. While the former has been partly solved, the latter has never been addressed in any published work. We propose a novel approach to solving both problems in the same framework. Particularly it preserves the effects relation of concurrent operations so that convergence is achieved automatically. Our work provides a new perspective into group editors and operational transformation algorithms.
7717414
A time interval based consistency control algorithm for interactive groupware applications
Traditional concurrency control methods such as locking and serialization are not suitable for distributed interactive applications that demand fast local response. Operational transformation (OT) is the standard solution to concurrency control and consistency maintenance in group editors, an important class of interactive groupware applications. It generally trades consistency for local responsiveness, because human users can often tolerate temporary inconsistencies but do not like their interactions be lost or nondeterministically blocked. This paper presents a time interval based operational transformation algorithm (TIBOT) that overcomes the various limitations of previous related work. Our approach guarantees content convergence and is significantly more simple and efficient than existing approaches. This is achieved in a pure replicated architecture by using a linear clock and by posing some constraints on communication that are reasonable for the application domain.
17885452
Commutativity-based concurrency control in groupware
Commutativity of operations is often exploited in concurrent systems to attain high levels of concurrency. A commutativity-based concurrency control method, called operational transformation (OT), has been actively researched in groupware over the past 15 years. However, much progress can still be made on more practicable approaches to developing and proving OT algorithms. Several constraints have been proposed previously but they are generally difficult to follow and verify in practice. This paper proposes an alternative approach to address this problem. A new consistency model is defined which greatly simplifies the design and proof of OT algorithms
14672206
Using marker-based deformable models for deriving anatomical models from medical image databases
The outcome of the application of a deformable model is dependent on its initialization and parameter settings. This is an obstacle to robust automatic segmentation. An approach to reducing the dependences is proposed in this paper based on geodesic topographic distance transforms from two manually or automatically placed markers. This is a novel method that uses object and background differentiation in deformable models via watershed theories. The implementation is based on efficient numerical methods. Experiments have shown that it is a highly promising approach. This approach has been applied to the determination of tissue characteristics in early childhood using a CT database of neonates. We believe that by relaxing dependences on the initialization and parameters this approach will enable a degree of automation needed for segmentation-based construction of organ models from large image databases, particularly when the markers can be determined automatically on the basis of a priori knowledge
13976225
WebPeer: A P2P-based system for publishing and discovering Web services
The use of Web services as an infrastructure of service sharing has made it possible to provide collaboration and interoperability in distributed computing environment. In this environment, service publishing and discovery are required as elementary functionalities for users to be able to locate the shared resources. The mechanism of service publishing and discovery with centralized architecture restricts the reliability and scalability of the distributed computing environment as the services and resources on the Web are fast emerging. The peer-to-peer (P2P) systems and applications, on the other hand, employ distributed resources to perform critical functions in a decentralized manner. This paper introduces Web Services Oriented Peer-to-peer (WSOP) architecture with a combination of centralized and decentralized characteristics, and presents a framework of service publishing and discovery model based on WSOP architecture. The prototype system - WebPeer implemented based on this model demonstrates the WSOP architecture can not only help to overcome the known obstacles in common Web Services infrastructure such as single node failure, but also extend the ability of the pure P2P systems, such as more efficiently locating the resources, increasing the interoperability between different P2P systems.
46225184
Spatial Technologies for Coastal Management
This demonstration will be presented at the 2004 National Conference on Digital Government Research. The third year results of the project "Digitalization of Coastal Management and Decision Making Supported by Multi-Dimensional Geospatial Information and Analysis" will be presented. Mobile wireless communications, internet web services, and web GIS are integrated into a web-based decision-making system for coastal management. Employing three-dimensional visualization technology, athe system also provides a visualization tool for multisource spatial-temporal data integration and uncertainty analysis. Also demonstrated is an interactive QuickBird image processing subsystem used for high resolution DEM and three-dimensional shoreline extraction of Tampa Bay.The goal of this project is to develop technologies to enhance the operational capabilities of federal, state, and local agencies responsible for coastal management and decision making. The pilot test site is along the Lake Erie coastline from Port Clinton to East Cleveland, Ohio. Research strategies are currently being applied to Painesville, OH and Tampa Bay, Florida. The demonstration will include the following sections.
30689406
Some hamiltonian properties of L1-graphs
Abstract A graph G is called an L 1 -graph if, for each triple of vertices u, v, and w with d ( u , v )=2 and w ∈ N ( u )∩ N ( v ), d ( u )+ d ( v )⩾| N ( u )∪ N ( v )∪ N ( w )|−1. Let G be a 2-connected L 1 -graph of order n. If δ ( G )⩾( n −2)/3 or σ 3 ( G )⩾ n , then G is hamiltonian or G∈ K , where σ 3 (G)= min {d(u)+d(v)+d(w) : {u,v,w} is an independent set in G }, K ={G : K p,p+1 ⊆G⊆K p +(p+1)K 1 for some p ⩾2}. Some results on the traceability of L 1 -graphs are also obtained.
34397649
Architecture support of a descriptor computer on object-orientation