M.R Firouzmanesh - Industrial Development and Renovation Organization of Iran ( IDRO ) & Islamic Azad University of Tehran
F Ronasi - Industrial Development and Renovation Organization of Iran ( IDRO )

The concept of "network" has become so popular during the past ten years that critiques are already talking about its abuse (Grandori and Soda 1995). However, despite its widespread use, there is no consensus about the appropriate definition of networks. Networks are often characterized with the concept of "loose coupling": Networks have been analyzed by researchers from many different disciplines with varied research interests and approaches. They have focused on different aspects and levels of network formation. Some researchers take an interpersonal perspective and emphasize the non-economic bases of social exchange and the importance of interpersonal relationships for productive cooperation, economic efficiency and innovativeness (Granovetter 1973,1995; Miettinen et al. 1999). Others emphasize the structural approach and focus on the configuration, number and quality of network ties (Nahapiet and Ghoshal 1998; Mattila and Uusikylä 1999). Still others focus on the institutional nature of networks and define them as a distinct organizational arrangement comparable to markets and corporate hierarchies (Powell 1990; Williamson 1991). There are many different types of networks in modern economies. They can be divided into vertical and horizontal networks according to the value-adding chain Finally, the stability of networks may also vary considerably. In general, networks are seen as a structure of loosely coupled actors, which makes it easy for new members to join them and for established partners to leave if they want. This could mean that the membership of networks would change quite rapidly and the relationships within them would be relatively unstable. However, networks are usually characterized by close interdependency and high-trust relationships among their members, both factors which contribute to the stability of networks. We can therefore characterize networks as stable and changeable at the same time. Key words : networks , Innovation Network , strategic management , Industrial network Theory , Innovation Model , Network Policies .

networks , Innovation Network , strategic management , Industrial network Theory , Innovation Model , Network Policies