The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
This work addresses the problem of external network reduction. The basic network reduction techniques were mostly developed in late 1970s when there were many demands for reduced network models. Due to the extensive network expansions and the growing requirement of network on-line estimation and optimization, the network reduction techniques need further development. This paper describes such developments.