2011 Cross Strait Quad-Regional Radio Science and Wireless Technology Conference

Research on the city networks

Bao-Feng GUO College of science and engineering, Jinan University,

Guang Zhou 510632, China E-mail: ggracess@sina.com

Abstract-The urban systems of the 20th century are from dense

centers into a network, which have highly variable nodes and

connections. Network city method are analyze briefly. First, transdisciplinary methods such as morphology and physiology are adopted to study the new urbanity phenomenon and then dynamically evaluated by four criteria of urban quality. It is

good for optimizing the existing city structure and improving urban qualities. It creates a new megalopolis design method. Important developing directions of urban network research in China are put forward finally.

KeyWords-urban planning : Network city Model

transdisciplinary study: urban reconstruction

I. INTRODUCTION

The research on urban network becomes a hot topic in the western world. It seems that a shift in spatial planning is taking place towards 'relational thinking', i.e. towards network thinking. Network thinking is a necessary element of urban planning in the 21 st century [ 1]. Nets are open forms and imply undefined limits. They are structured in nodes, in links between the nodes, nodes and links of differing sizes which we call: scales[2]. Typical for nets are the dominance of voids over matter and the coexistence of manifold networks.

One of the most influential theories concerning the networks of urbanism is "A City is Not a Tree" theory introduced by Christopher Alexander[3] and later refined by Kevin Lynch[4], Gabriel Dupuy[5], Castells, Hillier and

Webber , etc. Candilis-josic-woods[6] put forward some

theories concerning "web city", which is a high flexible,

non-centric, open-ended city through use of fuller

measure[7], Archigram suggested networked utopia city[8].

The network city terms "Megastructure" and "group form" were introduced by Jennifer Taylor in 1965. Metabolism make the project of Tokyo Bay of Japan [9], etc. Altogether, the research on the network city is in the

most urbanized area in the world, basing mainly on the

horizontal relationship in network city [10]. However,

there is not a generally accepted theory that can help us distinguish the 'good' area and methods from the 'bad' ones. The best method for defining the 'good city' is based on transdisciplinary work.

Oswald and Baccini extended the netcity theories (named NETZSTADT) in two directions. First, by locating

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contemporary analysis in a broad historical context and, second, by addressing the emerging issues of sustainable

resource utilization[ll]. As a transdisciplinary approach,

NETZSTADT is based on the Morphology of Nets from the architect and the Metabolism of the Anthroposphere from the natural scientist. The method is very complicated and yet lacks a dictionary to help potential users translate the findings into their own idioms [12]. Furthermore, public Participation process is needed [13]. China is made up by different people and their differing traditions, different landscapes and differing natural resources, different modes of productions, thus, the networks of the W est Country could not be compared to the networks of China. Further research on the topology of these networks should be done to define suitable method for Chinese urban and regional development.

A. Example We take a large-scale project--LuoGang as an example

of solution method for both the urban designers and the decision-makers.

The LuoGang administration center is located in the middle of LuoGang, Guangzhou, coverings a staggering area of 4.12 square kilometer. The west and south of the center is near the riverside, with a mountain to the east and north. It has a high density of population.

The paper begins with discussing the history and theory of network thinking in the context of urban planning. Then this paper gives an experiment example to illustrate the key-technique of network urbanism. A number of challenges for urban planning are pointed out fmally.

II. URBAN NETWORK

The Urban Networks include four basic elements: nodes,

connections, borders and scales(12), which is defined from morphology and physiology methods. The morphology indicators include Grain, Building Density, Shatter and Accessible indicator. The physiology indicators include density of resident population, density of working space, density of servicing facilities and density of public institution. These indicators' structure is complex and must be designed to reevaluate the elementary concepts of web city model. For example, although Ingram[14) , Joutsiniemi[15) put forward concept of accessibility indicators. Yet there are some important adjustments when implementing the model based on aggregate data into the disaggregate network context. The

July 26-30, 2011

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categories of accessibility suggested by Oswald and Baccini (2003) do not refer to administrative or territorial scales, to which other methodology refer to as reference parameter. Oswald and Baccini only provide limited insights about the accessibility to the network. This is because accessibility is not only regulated by the hierarchy of the last connecting branch, but is highly dependant of configuration of the whole of the network.

III. THE KEY-TECHNIQUE

A study area was chosen to focus on urban reconstruction. There are five procedural steps to reconstruct urban systems.

First, identification of the urban system in the terms of the model

Working with the aerial photographs, models obtained from RS are adapted to the territories in the GIS platform-Arcinfo. Territories are addressed and translated into an abstract model, which makes it possible to identify and evaluate the elements of the net (Fig. 1) [16].The observation territory is the same to the project perimeter always. The territories are one part of the net, which link the inside and outside of the systems. The models have the most important information of the city.

Second, structure the system into selected activities

,1km

tl YI.{3Ciill�tx --------. J:W 1-1 ;JJ.W Figure 1. Perimeter and node

Identifying network' elements(nodes and links, borders

and scale) to record the massive flows of persons, commodities and information, which concentrate at the nodes of the net. The element of network model are got from GPS and defmed via morphological and physiological indicators.

In order to design the nodes and links, the data of persons,

commodities and information must be a function of time and space.

Nodes are locations marked by a high density of people, goods and information. Connections represent the flows of people, goods and information between nodes. Borders are the spatial, temporal or organizational demarcations of the network. They are also called the perimeter and they defme the scale of the network.

The infrastructural networks are representing by the scale level. The models of Luogang are designed to have four

separate scales (national, regional, municipal, local), which

are identified by indicators of urban accessibility. The model must have two scale levels at least, including inferior scale

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level and larger scale level. In the dynamic web , the

concentrations on each scale level could be nodes of the other scale level. So, the network method is used to make research on any dynamic scale element and to get the whole structure of city network.

Third, shaping the model according to key resources and representing it by types of territories [17].

The Netzstadt method takes graded division of land into six types of morphological aggregates called territories (settlement, infrastructure, agriculture, forest, water and fallow land)[IS]. Via morphological and physiological indicators, the territories are separated from each other according to the influence in the nodal field.

Morphological tools (Grain, Density of building, Shatter and Accessible) describe the spatial characteristics of a territory. They are used to evaluate the network (Fig.2). The analyses shown in Fig.2 follow the Morphological analyses done by Oswald and Baccini. Density of building and Shatter can be marked and measured. Grain and Accessible can be measured indirectly. Grain, Shatter and Accessible can be obtained from the maps and photos. Density of building is got

form an estimate of the level number of the house. . .,

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r •

"

. ..... •• ·fIt 4110" •

.. '� '117

� • " f"', .. ,'lJ /1 .,....J: ���

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Figure 2. Morphological indicator: Grain, Density of building, Shatter and Accessible[ 16]

The average path length is a measure that defmes important characteristics about the topological depth of each node. Morphological analysis is performed by utilizing the dynamic reference frameworks of various phenomena and becomes building blocks of a nodal structure. To make a sufficient description of the position and context in the network, all possible connections (starting from any point within the network) should be evaluated to a topological depth, which could be identified on each scale by a characteristic path length. Though the single information for each path does not seem to be very productive, the superposition of the collected data could provide useful information on concentration and clustering of scale-related types of linkage and connection.

The organizational principle of the configuration of accessibility network does not represent the actual urban structure. Urban Networks represent locations and flows of persons, commodities and information. Density is the determinant feature of nodes and connections of network.

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Density of inhabitant, Density of workplace, Density of

institution can be taken as direct indicators for the economic growth of the town. These physiology indicators are getting from statistical survey. Physiology analyse is good for understanding the flows of persons, commodities and information in the material management systems.

Fourth, dynamically evaluating the urban features through city quality criterion.

Four urban quality criteria (Identification, Diversity,

Flexibility, Resource Efficiency) are used to evaluate the

above indicators (accessibility, building density, etc) of the

city. Various scale levels of the study area are evaluated. The evaluation helps testing the changes in the urban's

environment. Some changes have happened , some are

designed for the future. Fifth, finding the solutions and designing for new

morphology and physiology features. Through transdisciplinary analysis and the evaluation by

the urban quality criteria, the city web is evaluated to be superiority or inferior one. The original subjective evaluation is check up. Reconstruction process should be initiated when the urban systems do not meet the four criteria. That helps establishing the development target and fmding strategy for improving urban quality. The tools strengthen the network

functionality. For example , if lacking of Diversity and

Flexibility, the study areas of the city won't have good interregional relationship. The solutions are to layout more communal facilities for providing new opportunities for the planning. On the other hand, the net factors of low scale level and high scale level should be interconnected closely.

IV. CONCLUSIONS

After designing for new morphology and physiology

features, the net structure is optimized by changing the

topological depth of the nodes. It is possible to build node fields in an analytical way and come up with unbiased model where modeler's prejudices are not reflected in the modeling result. The planners could benefit from the proposed methodology, since it provides an indication of how to optimize the existing city structure and shape good urban form.

With the new "design" tools introduced in this paper the authors want to open up a new field for future planning practice. Its potential as a tool for analysis of complex urban problems is significantly increasing.

REFERENCES

[I] Jeroen van Schaick and Ina Klaasen. Introducing Urban Networks -Network Urbanism [EB/OL ],2008 .http://www.technepress.nl/pdf/28.prol.pdf.

[2] Franz Oswald. NETS FOR URBAN CAPACITY BUILDING[R].University of Addis Abab: ecbp, 2007.

[3] Christopher Alexander. A city is not a tree[J]. Translate by YIAN Xiao-ying, The Architect, 1986(24): 207 -218

[4] Kevin Lynch. City Form[M]. Translate by LIN Qing-yi , CHEN Zhao-hui , DENG Hua. Beijing : Huaxia publishing company , China, 2001.

[5] Dupuy G.. Urban Networks-Network Urbanism[M] , The Netherlands : Techne press, 2008: 3-29

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[6] Tom Avermaete. Another modem-the postwar architecture and urbanism of Candilis-Josic-Woods [M] , Rotterdam the Netherlands : NAI Publishers, 2006

[7] David F. Batten. Network Cities: Creative Urban Agglomerations for the 21st Century[J]. Urban Studies, 1995, 32(2): 313-327

[8] A guide to Archigram 1961-74[M], Great Britain : ACADMY EDITIONS Ltd,1944

[9] Preliminary research on network of urbanism and architecture-Discussion on Team IO[J]. The Architect, 2008.5: 67

[10] Jan Ritsema van Eck , Daalhuizen. The Randstad as a Network City[C/OL]. 45th Congress of European Regional Science Association, Vrije Universiteit Amsterdam 2005. http://www-sre.wu-wien.ac.atiersaiersaconfs/ersa05/papers/543.pdf

[11] Hawkes Dean. Netzstadt-designing the urban: placing non-place [EB/OL]. The Architectural Review 2004. http://findarticles.comip/articles/mi m3575/is 1284 215/ai 1140 62066.

[12] Oswald , F., Baccini , P. in association with Michaeli , M. Netzstadt-designing the urban [M].Basel: Birkhauser , Boston , Berlin, 2003

[13] Rodney H. Matsuoka, Rachel Kaplan. People needs in the urban landscape: Analysis of Landscape and Urban Planning contributions [J].Landscape and Urban Planning, 2008, 84:7-19

[14] Ingram, D.R. .The Concept of Accessibility: A Search for an Operational Form[J]. Regional Studies, 1971,5 : 101-107.

[15] Joutsiniemi, A.. Generic accessibility challenges axial maps-case Helsinki. Proceedings of 5th Space Syntax Symposium[C], Delft, 2005, 6

[16] Franz Oswald, Peter Baccini. Netzstadt: Designing the Urban [M]. Translate by Sun Jing, LE Mo-mo. Beijing : China Electric Power Press, China, 2007

[17] A m i R a n . Netzstadt -Net Model for Urban Design Review of Franz Oswald and Peter Baccini's Netzstadt-Designing the Urban [EB/OL] 2008.http://www.aiq.co.il/pageslEnglishArticle.asp?id=203

[18] Anssi JOUTSINIEMI Mark Michaeli[A]. NETZSTADT-THRESHOLD and Dynamic Scale. 9th International Conference on Computers in Urban Planning and Urban Management[C], London, 2005: 720-737

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