Thursday, December 24, 2009

Exurbia from the bottom-up: Confronting empirical challengesto characterizing a complex system

Ma Yan
Exurbia from the bottom-up: Confronting empirical challengesto characterizing a complex system
Daniel G. Brown, Derek T. Robinson, Li An, Joan I. Nassauer, Moira Zellner,William Rand, Rick Riolo, Scott E. Page, Bobbi Low, Zhifang Wang
Geoforum 39 (2008) 805–818
http://www.cscs.umich.edu/sluce/publications/geoforum_proof.pdf

Abstract:
This paper described empirical results from a multi-disciplinary project that support modeling complex processes of land-use and land-coverchange in exurban parts of Southeastern Michigan. Based on two different conceptual models, one describing the evolution of urbanform as a consequence of residential preferences and the other describing land-cover changes in an exurban township as a consequenceof residential preferences, local policies, and a diversity of development types, it described a variety of empirical data collected to supportthe mechanisms that encoded in computational agent-based models.
To simulate the residential preferences of residents, the utility model was utilized to reflect the residential location chooose by residents. This utility function the agents use is a variation of the Cobb-Douglas utility function. For the utility part, the socioeconomic characteristics of household is considered.

An agent-based approach to model future residential pressure on a regional landscape

Ma Yan
An agent-based approach to model future residential pressure on a regional landscape
Corentin M. Fontaine and Mark D. A. Rounsevell
Landscape Ecol (2009) 24:1237–1254
http://www.springerlink.com/content/w2636287tkxk1185/fulltext.pdf?page=1

Abstract:
This paper presents a framework to model future residential demand for housing in a polycentric region. The model, called HI-LIFE (Household Interactions through LIFE cycle stages), builds on Agent-Based Modelling (ABM) paradigms. In contrast to traditional equilibrium-based urban economics models that assume a homogenous population of rational actors, ABM focuses on the diversity of heterogeneous household agents and their behaviour in time and in space. The model simulates land-use patterns at the regional scale by integrating qualitative knowledge of agent location preferences with quantitative analysis of urban growth dynamics within a high resolution spatial modelling framework. The model was calibrated for the region of East Anglia in the UK using a semi-quantitative procedure. Simulation of urban dynamics for the future was undertaken for a 25 year period with the assumption of a continuation of baseline behavioural trends. The results demonstrated non-uniform, spatial patterns of urban sprawl with some locations experiencing greater urban development pressure than others. The town of Brundall, in particular, has a large potential demand for residential housing because of its proximity to the principle city, Norwich. As Brundall is also located close to a national park and a river, new housing development in this area would increase the risk of ecological impacts and flood damage. By modelling explicitly agent behaviour and interactions, ABM can simulate the response and adaptation strategies of a population to changing circumstances. This makes ABM especially well suited to the analysis of environmental change and landscape ecology pressures through scenario modelling.
In this paper, the accessibility was calculated by the Cobb-Douglas utility function.

Application of an integrated system dynamics and cellular automata model for urban growth assessment: A case study of Shanghai, China

Ma Yan

http://dx.doi.org/10.1016/j.landurbplan.2008.12.002
Ji Han, Yoshitsugu, Hayashi, Xin Cao
Landscape and Urban Planning Vol. 91, 2009, 133–141


Research Background
§By the accelerating urban growth, the accurate assessment of urban growth has become increasingly necessary.
§CA has been proved successful in assessing urban growth by viewing city as a complex system, however, CA model focus more on monitoring and simulating the spatial-temporal changes than on incorporating and interpreting the socioeconomic driving forces.
§Therefore, the integration of CA with other socioeconomic models is urgently needed.

Research Purposes

§To build a model which would be reasonable for evaluation of urban growth driven by human and natural factors at different scales.
§ To test the accuracy of the integrated model and specifies both socioeconomic variables and spatial variables.
§If the accuracy of integrated model is competent for urban growth simulation, then project the urban growth of Shanghai city up to 2020

Research Method
§In the study, an integrated system dynamics (SD) and CA model is developed with its framework. (showed in figure right)
§The problems are mainly focused in two aspects:
(1) A real change of urban land driven by socioeconomic variables
(2) spatial pattern of urban expansion affected by physical factors.

Research Results
§Accuracy test (right figure) showed that SD module is competent for urban growth simulation assessment.
§Kappa statistics between simulation results and actual land use map in 1989 and 2000 is 0.53 and 0.62, suggesting the parameters are reasonable and CA module is capable for simulating the spatial growth of urban land in Shanghai.

Thinking
§By setting the socioeconomic factors as simulation conditions, it is successful to improve urban growth simulation using CA model
§Besides the spatial simulation, further simulation could be done by creating agents based on CA simulation results
§SD model is possible to be combined with CA and agent-based system.

The interaction of segregation and suburbanization in an agent-based model of residential location

馬妍 
The interaction of segregation and suburbanization in an agent-based model of residential location
Wrote by: Ciriyam Jayaprakash, Keith Warren, Elena Irwin, Kan Chen
Environment and Planning B: Planning and Design Vol. 36, 2009, 989 -1007

http://www.envplan.com/epb/fulltext/b36/b33029.pdf

Abstract:
A model of the interaction of segregation and suburbanization in determining residential location is prsented in this paper. The model incorporates differential income between two classes of agents, a simplified market mechanism for the purchase of housing, and a simple geographic structure of one central city and four symmetrically arranged suburbs. Agents derive utility from neighborhood racial composition, the size of their lot, private amenities that are specific to neighborhoods, and public amenities that stretch across municipalities. It is found that the public amenities term leads to a positive feedback loop in which migration to suburbs increases the public amenities in those municipalities while lowering amenities in the central city, thus sparking further migration. When the minority agents are uniformly less affluent than the majority agents, this dynamic produces discontinuity in segregation as measured by centralization. Such discontinuities are typical of first-order phase transitions. When minority and majority incomes overlap, significant regions appear over which there are multistable equilibria at high and low levels of segregation, along with considerable sensitivity to the initial distribution of minority agents.
Agent utility:

Racial-composition preference:

The proportion of ratial was considered
Spatial preference:

Space available in block and congestion were considered
Preference for private amenities:

The neighborhood of the cell and disposable income of household were considered
Preference for public amenities:

Taxes collected in municipality was considered



Thursday, December 17, 2009

12月17日 久保田

「地方都市郊外戸建て住宅地における居住者の居住選択意向-福井市郊外4都市を事例として-」
菊地 吉信・野嶋 慎二
(社)日本都市計画学会 都市計画論文集 No.42-3 2007年10月
http://pkawap20.ce.t.kanazawa-u.ac.jp/~urbanplan/all/pdf/2007-42-3-37-217.pdf

概要
少子高齢化の進む今日の日本においては都市のコンパクト化を進めることが求められている。そのために、既存の良好な住宅・宅地のストックを持続的に活用すると共に、郊外部での新規供給はできるだけ抑制することが望ましいと考えられる。
しかし、地方都市郊外では今もなお新規住宅地開発が進んでおり、一方、高度経済成長期からバブル期にかけて活発に供給された住宅地では、住宅の建たない空き区画も目立っている。
このような状況においては、既存住宅地の住環境を再検討し、問題点を改善することもあわせて検討しなければならない。
本研究では、福井県福井市の戸建住宅地を対象に、実際に居住している世帯の居住選択意向を明らかにすることを通じて、既存郊外住宅地の住宅・宅地ストックとしての利用可能性を高める方向性について検討することを目的としている。
また、次の三点に注目して分析を行っている。1.郊外住宅地居住者の入居経緯について、世帯属性と住宅・宅地の取得方法に着目して明らかにする。2.世帯の今後の居住意向について「住み続け意向」「住替え意向」の特徴を明らかにする。3.分析結果を踏まえ、住宅地の住宅・宅地ストックとしての利用可能性を高めるための方策について考察する。
アンケートにより調査を行い、そこで得られた結果を考察している。
結果として、居住の継続を望む世帯が多いものの、必ずしも積極的な理由からではない。一方、住替え意向を持つ世帯の多くは老後の生活への不安を主な理由としており、今後、現在の居住者構成のまま高齢化が進んだ場合、住替え意向が急速に高まる可能性もある。また、若年層において二次取得が一定の割合を占めること、住替え意向の高いこと、近居を目的とした入居の多いことが明らかとなっている。これらの結果を踏まえ分析を行い、個々の住宅地レベルでの対応のみならず、世代間の異なるニーズを把握し、地域の状況に即した都市レベルでの対応が必要となるとしている。

参考ポイント
住み続け・住替え意向における、世帯の意思決定の理由がアンケートをもとに示してあったので、モデル構築の際に参考にしようと思う。住宅・宅地の選択は様々な要因が絡んでくると感じるので、全てを対象とするのではなく、ある程度範囲を絞って考慮していこうと思う。

Wednesday, December 2, 2009

12月3日 久保田

「地方都市のコンパクト化が生活者行動パターンに与える影響:
選択肢間の類似性を考慮した集計型離散選択モデルを用いた分析」
山根 公八・張 峻屹・藤原 章正
(社)日本都市計画学会 都市計画論文集 No.42-3 2007年10月
http://pkawap20.ce.t.kanazawa-u.ac.jp/~urbanplan/all/pdf/2007-42-3-100-595.pdf

概要
本研究では、地方都市を取り上げ、コンパクトシティの形成が交通行動パターンに与える影響を適切に評価できる実用的なモデリング手法の構築と、それを用いた政策のシミュレーション分析を試みている。分析にあたっては、行動パターンのパターン間の類似性や選択肢間の認知性の違いを考慮した集計方離散選択モデルを用い実施している。
結果としては、
①行動パターンを目的変数とし、個人属性変数、都市構造変数を説明変数として構築した集計型離散選択モデル(r-NLモデル)と一般的なNLモデルを宍道湖中海都市圏のデータで構築し比較した結果、r-NLモデルはNLモデルと比較して遜色ない精度や現況再現性を確保できることが明らかとなった。
②政策分析として、都心居住を推進したケース(コンパクト化)を数ケース設定し、シミュレーションした結果、都心居住を行えば複雑な行動パターンは増加し、利用交通手段では、徒歩・二輪・公共交通機関利用が増加するなど妥当な推計結果となり、今回推計したモデルに問題が無いことが明らかとなった。

感想
シミュレーションにおいて、都市のコンパクト化によって生活者の行動パターンが予想通りに変化しているところがおもしろいと思った。ある程度道筋を立て研究を進めていくことが必要だと感じた。シミュレーション分析の方法などしっかりと勉強していきたい。