Optimization in Internet Information Service Todor Stoilov, Kasimira Stoilova and Zlatka Ivanova Institute of Computer and Communication Systems, Bulgarian Academy of Sciences, 1113 Sofia, Acad.G.Bontchev BL.2 tel.: +(359) 2 979 2774, fax: +(359)2 72 39 05, e-mail: todor@hsi.iccs.bas.bg Abstract. The information service in Internet, which performs on-line optimization calcu- lations, is considered. The optimization concerns evaluation of optimal portfolio in financial investments. Thus the information service supports the on-line decision-making in invest- ments. The evolution of the information services is considered as development of hierarchical Web based client-server software suit. The improvements in the functionality of the services results in increasing the hierarchical levels of the server side algorithmic and software struc- ture. A case of optimal resource allocation in investment process is presented. The goal of the system is to offer in real time solutions of portfolio optimization problems, according to the dynamically changes of the input data, related to the assets’ returns. An optimization portfolio problem is defined and new algorithms are derived, satisfying real time requirements for the problem solution. The algorithms are incorporated in WAN based information system. 1 Introduction The meaning of the term WAN (Wide Area Network) is often used to describe dis- tributed information systems that operate in Internet environment. Although WAN are complex technological and informational systems, the importance and the benefit of WAN origins from the information services, offered by WAN to the users [1,4]. The information services operate through the global network and can be accessed by the wide Internet community of users. Nowadays the Internet users assume that the global network is the environment, which offers different information services, ac- cessed by appropriate computer and communication tools [2,6]. The importance of the information services for the management of different technical, economical, and social systems determines the goal of this research to include the optimization func- tionality in the WAN based information services. The optimization is one of the most complex procedures for treating the information. It consists stages of problem defini- tion, parameter identification and problem evaluation. Due to the complexity of the information treatment, the information services have to cope real time requirements to provide on-line optimization functionality [3,5]. This research targets the implemen- tation of the optimization of resource allocation in on-line information service, related to the portfolio optimization of investments. Such a system supports the real-time decision making in investment process, following in time the fast and dynamical changes of the performance of the financial assets. The paper identifies the system