Björn Knutsson

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Most massively multiplayer game servers employ static partitioning of their game world into distinct mini-worlds that are hosted on separate servers. This limits cross-server interactions between players, and exposes the division of the world to players. We have designed and implemented an architecture in which the partitioning of game regions across(More)
Previous studies of large-scale (multimillion node) Kademlia-based DHTs have shown poor performance, measured in seconds; in contrast to the far more optimistic results from theoretical analysis, simulations and testbeds. In this paper, we unexpectedly find that in the Mainline BitTorrent DHT (MDHT), probably the largest DHT overlay on the Internet, many(More)
Proxy-based transcoding adapts Web content to be a better match for client capabilities (such as screen size and color depth) and last-hop bandwidths. Traditional transcoding breaks the end-to-end model of the Web, because the proxy does not know the semantics of the content. <i>Server-directed transcoding</i> preserves end-to-end semantics while supporting(More)
STUDY DESIGN A cohort study based on the Swedish Spine Register. OBJECTIVE To determine the association between body mass index (BMI) and outcome of lumbar spine surgery for spinal stenosis. SUMMARY OF BACKGROUND DATA Several small studies have sought to evaluate the importance of obesity in relation to results after surgery for lumbar spinal stenosis(More)
Mobile wireless devices have intermittent connectivity, sometimes intentional. This is a problem for conventional Mobile IP, beyond its well-known routing inefficiencies and deployment issues. DHARMA selects a location-optimized instance from a distributed set of home agents to minimize routing overheads; set management and optimization are done using the(More)
The birth and evolution of Peer-to-Peer (P2P) protocols have, for the most part, been about peer discovery. Napster, one of the first P2P protocols, was basically FTP/HTTP plus a way of finding hosts willing to send you the file. Since then, both the transfer and peer discovery mechanisms have improved, but only recently have we seen a real push to(More)
We investigate the prospect of applying runtime verification to cheat detection. Game implementation bugs are extensively exploited by cheaters, especially in massively multiplayer games. As games are implemented on larger scales and game object interactions become more complex, it becomes increasingly difficult to guarantee that high-level game rules are(More)