Abstract
In the paper, hierarchical combinatorial synthesis of Web-hosting system is described. The composition problem is examined as analysis and selection of system component alternatives (e.g., hardware alternatives, software alternatives, communication alternatives). The modular design process is based on Hierarchical Morphological Multicriteria Design (HMMD) approach: (i) design of a tree-like model for the system, (ii) generation of design alternatives for each leaf node of the system model, (iii) generation of criteria and their scales for each node of the system model, (iv) assessment of the design alternatives upon the corresponding criteria, (v) multicriteria analysis of the alternatives for system components/parts to get ordinal estimates of quality for each design alternative, (vi) composing the selected alternatives into a resultant combination or a composite design alternative for the higher hierarchical level of the system model (while taking into account ordinal quality of the alternatives above and ordinal quality of compatibility between the alternatives). The multicriteria analysis of the design alternatives and their composition is based on a hierarchical Bottom-Up framework. A two-criteria combinatorial problem (morphological clique problem) is used for the composition and Pareto-effective solutions are searched for. An example of Web-hosting system consists of the following basic system parts: (a) facilities (servers, telecommunication facilities), (b) Internet access, (c) software part (Web server, Web technology). The set of basic criteria involves the following: price, reliability, scalability, stability of work, maintenance cost, etc. Numerical examples illustrate the system modeling and design processes.