Analysis of an Artificial Hormone System

The increased complexity of modern networks and the increasingly dynamic access patterns in multimedia consumption have led to new challenges for content delivery. Dynamic networks and dynamic access patterns result in a complex system. To deliver content efficiently we introduced an artificial hormone system that is capable of handling the dynamics, is self-organizing, robust and adaptive. The content placement problem is NP complete and is closely related to several hard problems including edge-disjoint path routing, scheduling and the bin packing problem. The evaluation of self-organizing algorithms brings also a real challenge. For a first evaluation we created and ILP model of the problem. It is applied to get the exact optimum that serves as a bound in the evaluation of the solution algorithms. In this paper, we examine the convergence of the algorithm and found that the hormone levels converge to a limit at each node in the typical cases. We form a series of theorems on convergence with different conditions by starting with a specific base case and then we consider more general, practically relevant cases. The theorems can be proved by exploiting the analogy between the Markov chains and the artificial hormone system

Context-aware hoarding of multimedia content in a largescale tour guide scenario: a case study on scaling issues of a multimedia tour guide

Abstract: This paper discusses scaling issues of a mobile multimedia tour guide. Making tourist-information available in a substantially large geographical area (e.g. a federal state in Austria) raises new questions, compared to providing similar information in a limited area (such as a museum). First, we have to assume a heterogeneous network infrastructure containing high and low bandwidth links and even total network loss. Video streaming is therefore not possible at any place. Secondly, the total amount of data grows linearly to the number of Points of Interest (POIs) which are augmented by the tour guide. Therefore, a preloading of all data onto a device with limited storage is not possible. A possible solution to these problems is hoarding, i.e. preloading an "appropriate" subset of data. The crucial question is to find the proper subset in dependence of the actual context. The paper discusses the questions o

Introduction to the special issue of best papers of ACM MMSys 2013 and ACM NOSSDAV 2013

10.1145/2557424ACM Transactions on Multimedia Computing, Communications and Applications101 SUPPL