ComSIS has entered the fifth year of its publishing and the ninth issue is in front of you. So far, we have published 61 papers in seven regular issues and two special issues focusing on e-Learning and Advances in programming languages. It is my pleasure to say that each ComSIS issue is indexed now at the DBLP Computer Science Bibliography from University of Trier, as well as at the Center for Evaluation in Education and Science (CEON) with National Library of Serbia and Ministry of Science of Republic of erbia, where impact factor IF5 for 2007 is 0.575.

Let me announce that Mirjana Ivanovic from University of Novi Sad has become Vice Editor-in-Chief, since January 2008. Also, the following new members joined ComSIS Editorial Board and Editorial Council: Zora Arsovski, Dragic Bankovic, and Goran Devedžic from University of Kragujevac, Milena Stankovic and Slobodanka Đordevic-Kajan from University of Niš, and Dragan Domazet from Faculty of Information Technology in Belgrade. We hope that their support will significantly contribute to the ComSIS mission.

This issue of ComSIS contains one invited and seven regular research papers. While some of the papers present mostly theoretical research results, we may say that many of them present results from various application domains.

The invited paper comes from the distinguished authors Guangbin Fan from Intel China Research Center from Beijing, Ivan Stojmenovic from University of Ottawa, and Jingyuan Zhang from the University of Alabama. Their research results presented in the paper concern location management, as one of the fundamental issues in wireless communication networks. The authors state that no matter how well the location areas are designed, there exist two problems. One is that the boundary cells between two location areas are always burdened with all location update signaling, while the cells inside a location area do not have any location update signaling at all. The other problem is that the excessive ping-pong location update effect occurs when a mobile terminal is moving back and forth between the two neighboring location areas. The authors propose in the paper a triple-layer location management strategy to eliminate the generalized ping-pong effect, thus greatly reducing the total location update cost. Simulation results show that the triple-layer strategy outperforms the existing schemes designed to reduce the ping-pong effect.

Evaluation of software complexity is often a hot topic not only in research, but also in software industry. Today, there is a variety of proposals for validation process of complexity metrics. Sanjay Misra and Ibrahim Akman in their paper "Applicability of Weyuker’s Properties on OO Metrics: Some Misunderstand-ings" propose that Weyuker’s properties play an important role in evaluating software complexity measures and that they are assumed to be also accepted as an evaluation criterion for OO metrics. Although these properties are simple and straightforward, sometimes the authors of new measures misunderstand the interpretation of these properties, mainly because they were not developed originally for OO programming languages. Therefore, the authors in the paper discuss the interpretation, relevance and the applicability of Weyuker’s properties in OO domain.

Web Information Extraction Systems (WIES) are tools that transform Web pages into program-friendly structures that can be used by a variety of Web applications and services. In their paper "Model of a User Friendly System for Library Cataloguing", Greydon Buckley and Jozo Dujmovic consider a recent WIES survey, which found that despite the great necessity for WIES the automation degree is generally rather low. Search engines like Web browsers solve the general problem of finding relevant data, however it is up to the user to sort, filter, and evaluate it. Decision support methods such as LSP can turn raw data into formal evaluations, but they are generally disconnected from the Web – the most up-to-date, widely-used, and convenient source of data available. The authors demonstrate how LSP can be connected to the Web, so that live data from e-commerce Web sites can be used in consumer-oriented system evaluations.

Žarko Živanov, Predrag Rakic, and Miroslav Hajdukovic in their paper "Using Code Generation Approach in Developing Kiosk Applications" state that kiosk automata are usually programmed either using high level programming languages or using HTML in conjunction with Web browser. They analyze a vast range of kiosk automata and their derived common characteristics, and propose an approach to programming kiosk applications based on a domain specific language, designed specifically to meet the needs of developing kiosk applications that are usually programmed using high level programming languages and are deployed on kiosks with touch-screen monitors. The main goal is to provide a rapid and an efficient development of such applications.

Library information systems are an interesting and challenging application domain for software engineering. Katarina Belic and Dušan Surla in their paper "Model of a User Friendly System for Library Cataloguing" present a generic model of user requirements and architecture of a system for library material processing in the UNIMARC format, not requiring a specific knowledge of cataloguing formats. The Unified Modeling Language (UML 2.0) is used for the model specification. The proposed model can be implemented as an independent software component that can be integrated easily into an existing library software system.

The next two papers also regard wireless communication networks, as one of the emergent application domains today. In their paper "Modeling of Login Procedure for Wireless Application with Interaction Overview Diagrams", Vera Plavšic and Emil Šecerov present a UML model of the login procedure, which is a part of an application developed for large stores and intended for use as a customer support during the shopping session. The procedure is implemented within an access control system over a wireless network.

Wireless sensor networks (WSN) are networks consisting of a large number of battery powered sensor devices interconnected by radio waves, aimed at collecting physical data in the given environment and sending it to one or more collector nodes. Žarko Živanov, Predrag Rakic, and Miroslav Hajdukovic in their paper "Wireless Sensor Network Application Programming and Simulation System" state that it is often expensive or impossible to charge or replace the battery of a node, and therefore prolonging the node's lifetime is essential. They present a WSN application programming and simulation system, suitable for WSN application development for both resource constrained and unconstrained hardware. Developed programs can be tested within the simulator, or (with source unchanged) executed directly on hardware.

Salam A. Najim, Zakaria Al Oumari, and Samir M. Said in their paper "On the Application of Artificial Neural Network in Analyzing and Studying Daily Loads of Jordan Power System Plant" propose a neural network approach to forecast AM/PM Jordan electric power load curves based on several parameters, such as temperature, date, and the status of the day. The proposed method has an advantage of dealing with not only the nonlinear part of load curve but also with rapid temperature change of forecasted day, weekend and special day features. The proposed neural network is used to modify the load curve of a similar day by using the previous information. The suitability of the proposed approach is illustrated by an application to actual load data of Electric Power Company in Jordan.

On behalf of the ComSIS Consortium, let me use this opportunity to give my great thanks to the reviewers and all of the authors for their high-quality work, great efforts, and remarkable enthusiasm.

Ivan Luković