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The last hop of global notification delivery to mobile users. Matching preferences, context, and device constraints.
(Research report; Forskningsrapport, 2004)
Events injected by publishers into a publish/subscribe system may reach users through a variety of devices: a stationary desktop, a laptop, a mobile phone, etc. We argue that the "last hop" -- from the network to the output device -- has unique properties, owing to the mobile nature of these devices, and as such demands special consideration. In particular, user's preferences and location may limit ...
The Longcut Wide Area Network Emulator. Design and Evaluation
(Research report; Forskningsrapport, 2005)
Experiments run on a Grid, consisting of clusters administered by multiple organizations connected by shared wide area networks (WANs), may not be reproducible. First, traffic on the WAN cannot be controlled. Second, allocating the same resources for subsequent experiments can be difficult. Longcut solves both problems by splitting a single cluster into several parts, and for each part having one ...
Vortex. An event-driven multiprocessor operating system supporting performance isolation
(Research report; Forskningsrapport, 2003-06-13)
Vortex is a new multiprocessor operating system that is entirely event-driven. The Vortex kernel, as well as its applications, are structured as stagesthat communicate through event passing. Each stage is a small finite state machine. The event architecture is efficient and allows Vortex to balance load across the processors automatically. Vortex uses an Event Scheduling Tree (EST) on each CPU. ...
Performance isolation and adaption in the Vortex Kernel
(Research report; Forskningsrapport, 2003-01-10)
Vortex is a new multiprocessor operating system kernel intended for emerging Internet service applications. The architecture is based on SEDA's staged computational model. Vortex provides mechanisms for performance isolation and dynamic adaptation. Performance results validate that the resource control mechanisms of Vortex are effective, and that Vortex significantly outperforms Linux on single-threaded ...
3D visualization of weather forecasts and topography
(Research report; Forskningsrapport, 1994-09)
Advances in computing power and graphics have increased the use of graphics in weather forecasting. This includes 3D animation sequences and geographical information systems. The paper addresses the main problems and presents preliminary results of the visualization of atmospheric models in conjunction with the underlying topography. The goal is among others to make a sort of 3D satellite pictures ...
Security in the PASTA project
(Research report; Forskningsrapport, 1997-02-04)
This paper presents the system model for the work on security in the Pasta project. We present the objectives of the security effort, the threats we will consider, and those we will not consider. As such, the paper describes the environment which applications must be prepared to face, and still provide users with the desired degree of privacy.
Cooperation through information interchange in StormCast
(Research report; Forskningsrapport, 1990)
This paper addresses the cooperation between different expert system modules in a networking environment. StormCast - a distributed artificial intelligence application for severe storm forecasting is used as a case to obtain practical results. Two key aspects is investigated, first the representation of knowledge in this kind of environment is outlined. Then the cooperating nature of a group of ...
Policies and metrics for fair resource sharing
(Research report; Forskningsrapport, 2006)
Performance isolation is essential to operating systems shared by dependable services. Unfortunately, most such systems, including real-time operating systems and VMMs, only fairly divide and account for CPU cycles. We submit that dependable services require specifying and enforcing policies for all resources, and that current metrics for evaluating fair sharing are insufficient. This paper proposes ...
FirePatch. Secure and time-critical dissemination of patches
(Research report; Forskningsrapport, 2006)
Because software security patches relay information about vulnerabilities, they can be reverse engineered into exploits. Tools for doing this already exist. As a result, there is a race between hackers and end-users to first obtain patches. In this paper we present and evaluate FirePatch, an intrusion-tolerant dissemination mechanism that combines encryption, replication, and sandboxing such that ...
Using a virtual event space to understand parallel application communication behavior
(Research report; Forskningsrapport, 2003)
We have developed EventSpace, a configurable data collecting, management and observation system for monitoring low-level synchronization and communication events with the purpose of understanding the behavior of parallel applications on clusters and multi-clusters. Applications are instrumented by adding data collecting code in the form of event collectors to an applications communication paths. ...