Christian Nyberg

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— Performance modeling is an important topic in capacity planning and overload control for web servers. We present an M/G/1/K*PS queueing model of a web server. The arrival process of HTTP requests is assumed to be Poissonian and the service discipline is processor sharing. The total number of requests that can be processed at one time is limited to K. We(More)
Performance modeling is an important topic in capacity planning and overload control for web servers. We present a queueing model of an Apache web server that uses bursty arrival traffic. The arrivals of HTTP requests is assumed to be a Markov Modulated Poisson Process and the service discipline of the server is processor sharing. The total number of(More)
This paper examines load balancing issues relating to a distributed CORBA-based Service Control Point. Two types of load balancing strategies are explored through simulation studies: (i) a novel ant-based load balancing algorithm , which has been devised specifically for this type of system. This algorithm is compared to more traditional algorithms, (ii) a(More)
During recent years we have seen several large-scale crises. The 9/11 terror attacks, tsunamis, storms, floods and bombings have all caused a great deal of damage. A common factor in these crises has been the need for information and one important source of information is usually web sites. In this work we investigate and design an overload control system(More)
One problem with web servers is that they are sensitive to overload. The servers may become overloaded during temporary traffic peaks when more requests arrive than the server is designed for. Because overload usually occurs rather seldom, it is not economical to overprovision the servers for these traffic peaks, instead admission control mechanisms can be(More)
Scalable and reliable distributed object-oriented computing (DOC) middleware systems is an important technology in, for example, telecommunications service logic and distributed web servers. The Common Object Request Broker Architecture (CORBA), developed by the Object Management Group (OMG) is a specification of a common platform for DOC systems. CORBA(More)