تعیین رتبه و میزان پیوندِ شبکه‌ایِ جهانیِ تهران با استفاده از مدل «جی. اِن. سی »

1. Introduction
Information modes and the information revolution have created an integrated global economic network. Rapid globalization has been one of the most influential phenomena in the present century. The development of globalization has redefined a key role for cities, particularly applicable to metropolises and large cities. In this era of globalization, cities and metropolises form a global network of activity that is a series of interconnected hubs and nodes. Cities within this global network are represented as nodes connected by flow through space; they have been described as “network-cities” (Castells, 1996). However, in the global urban network, some cities have a focal function that makes them dominant and others are much less important. Within this global network, some world cities command strategic nodes (Friedmann, 1986, Sassen, 1991); while others can be classified as less well-connected or as resistant cities (Short, 2004). In developing countries, metropolitan areas and capital cities have important roles nationally as sub-network nodes. Many researchers have emphasized that in the current era, cities have an important role in terms of determining conditions of human life and people’s quality of life.
In this paper, an attempt is made to determine, examine and analyze Global Network Connectivity (GNC) for the metropolis of Tehran. The GNC model used in this study is explained in the methodology section. The available literature relating to Tehran's position in terms of the World Cities’ Network is limited; however, there are some noteworthy analyses. Studies of Beaverstok and et al., (1999), Taylor (2002, 2001, 2004), Harris (2009), Stanley (2003), Short (2004), (2009), Devriendt et al., (2009), Bassens (2009, 2011), Sarrafi et al., (2009) and others have shown that despite descriptions of Tehran as one of the world’s major cities (with a population of 8.5 million), it has yet to be identified as a world or global city in world ranking within the period 2000 - 2010. Short (2004) reported that Tehran is a Black Hole in the network of world cities. Tehran can be regarded as a resistant city because of its ideological standing and its radical principles. Furthermore, Tehran cannot be regarded as a world city because of its resistance to globalization. 
 
2. Methodology
Taylor has pointed out that the need for a precise specification of the world city network is obvious. Without this, there can be no detailed study of its operation - its nodes, their connections and how they constitute an integrated whole" (Taylor, 2001). This study is based on documentary, descriptive and analytical methods. The author used the GNC model to determine Tehran’s ranking and connectivity in the global cities’ network based on the data from 315 cities and 100 firms worldwide that were gathered by GaWc. This model was formulated by Peter Taylor (2001) and used in GaWc (Globalization and World Cities Research Network) contributors and researcher's studies and articles from 2001 to 2014. Taylor explained this model in his book entitled "World Cities Network Analysis" that was published in the year 2004. In addition, the networks and cities themselves constitute the networks’ nodes (especially in relation to those cities considered command-and-control-centers) in the Taylor Model. Cities in Taylor’s “GNC model” are connected indirectly through constituent subcomponents. However, in this paper we have used Excel and SPSS for data processing and to get outputs for analysis. Algorithm charts are used to show conclusions. The GNC model is formulated in the formula below:
 
 
This model has been used in articles and academic papers to examine cities’ positions on the GNC.
 
3. Results and Discussion
In this paper, we showed rank, global network connectivity, and the real position of Tehran in the world cities’ network. Analysis on the data of firms in the Service value (V) matrix demonstrated that Tehran, by means of its proportion of connectivity scored 0.0019 in gross connectivity. Its GNS was 0.122 and its rank was 203 among 315 world cities. These results show that Tehran is positioned at a distance in terms of global cities’ positioning in the world cities’ network. International and globalized firms and corporations are not concentrated within the geography of Tehran city and many of them are absent from economy and infrastructure of Tehran in the year 2013. Statistics for Tehran are also evaluated for Tehran Elemental Interlock, Gross Connectivity (GNC) and finally global network connectivity to determine the situation of its connectedness in the world cities’ network. The results of those stages are as follows:

Tehran had weak connectivity in comparison with other global cities in the world cities’ network. Evaluations for interlock and connectivity of Tehran compared with other global cities by firms showed weak advanced product services.
Tehran also had a weak position in relation to the region of the Middle East and in the Islamic region.  Cities such as Dubai, Istanbul, Manama and some other cities in the Arab region had better ranking and position than did Tehran. Tehran ranked 15 out of 22 selected cities for studying in the region of the Middle East.
Statistics of population and area of a city alone do not determine its ranking among global cities. Evaluations such as that require much more refined definition. The definition of a global city requires analysis in terms of function, economics and social phenomena as well as demographic data.

 
4. Conclusion
In the years from 2000 to 2013, the main ideas on rank and position of Tehran on the global cities’ network were based on personal or non-statistical calculations. In this study, we used the GNC model to examine and analyze Tehran’s global positioning. Our study showed that Tehran, for the years 2000-2010, was not included in the ranking of global cities and as results show, it did not have a good position in the Middle East or in relation to other Islamic cities.
In relation to the problem described above, the following suggestions can be offered:

More researches are essential in order to determine the root cause of Tehran's problems on issues of globalization.
Tehran needs to adopt some specified policies, diplomacy and strategies pertaining to its global position.
Tehran needs to maintain its human and trained resources for use in advanced sectors of the city’s economy. This resource can help Tehran’s positioning in terms of global network ranking.
Tehran should invest and support advanced producer services as a command and control function of the city. Those services play the main roles in economic improvement of the city.

Finally, Tehran needs to develop transnational strategic planning to obtain a new role and function in the global cities’ network. This matter needs to reform urban democracy, policy, planning, management, improvement environment quality, social condition in the city as a whole.