13 research outputs found
A Scalable Middleware Solution for Advanced Wide Area Web Services
To alleviate scalability problems in the Web, many researchers concentrate on how to incorporate advanced caching and replication techniques. Many solutions incorporate object-based techniques. In particular, Web resources are considered as distributed objects offering a well-defined interface. We argue that most proposals ignore two important aspects. First, there is little discussion on what kind of coherence should be provided. Proposing specific caching or replication solutions makes sense only if we know what coherence model they should implement. Second, most proposals treat all Web resources alike. Such a one-size-fits-all approach will never work in a wide-area system. We propose a solution in which Web resources are encapsulated in physically distributed shared objects. Each object should encapsulate not only state and operations, but also the policy by which its state is distributed, cached, replicated, migrated, etc
Performance Modeling of Proxy Cache Servers
Jelen disszertáció keretében a Proxy Cache szerverek hatékonyságát vizsgáltam meg.
A disszertáciĂłban bemutattam az általunk általánosĂtott Proxy Cache szerver modellt majd megvizsgáltam,
hogy milyen paraméterek mellett éri meg Proxy Cache szervert üzemeltetni.
További általánosĂtáskĂ©nt megvizsgáltam azt az esetet is, amikor a Proxy Cache szerver valamint a Web szerver nem megbĂzhatĂł.
A dolgozatban tanulmányoztam azt az esetet is, amikor az érkezési folyamatok nem Poisson folyamat,
hanem Ăşgynevezett GI - General interarrival" folyamat, melyet az Ă©rkezĂ©si idĹ‘közök várhatĂł Ă©rtĂ©kĂ©vel Ă©s a relatĂv szĂłrásnĂ©gyzetĂ©vel jellemzĂĽnk,
valamint a kiszolgálási idĹ‘ bármilyen általános eloszlásĂş lehet. Az Ăgy kapott modellben a rendszerparamĂ©terek kiszámĂtásához a GI/G/1 approximáciĂłt használtam.
Végül megvizsgáltam hogyan milyen hatással van a heterogén forgalom a Proxy Cache szerverek hatékonyságára.
In this dissertation I described the mathematical model of Proxy Cache servers and
I studied the conditions under which installing a Proxy Cache server becomes beneficial.
I also analyze how various factors affect the performance of a Proxy Cache server.
Than, I generalize the performance model of the Proxy Cache server using a more realistic case
when the Proxy Cache server and the remote Web server are unreliable.
Later I analyse the case when the arrival process is a general (GI) arrival process characterised by a mean arrival rate
and a squared coeficient of variation (SQV) of the inter-arrival time and the service time may have any general distribution.
To obtain the response times I used the GI/G/1 approximation. Than I examine the performance behavior of a Proxy Cache server
when we use heterogeneous trafic. In this thesis we describe the modified multi-class queuing network model of the Proxy Cache server