Recently in simulation Category


Recently published:

Huang, Arthur and David Levinson (2012) STREET: Where simulation meets reality Cultivating Change in the Academy (eds. Duin, Ann Hill et al.)

Simulations and games are receiving increasing attention in teaching in higher education. In this context, we developed a series of simulation modules (STREET) in transportation engineering education and applied them in teaching undergraduate and graduate transportation courses at the University of Minnesota. After several years, we contend that they represent an effective pedagogical tool in transportation education. In this chapter we describe our motivation for this work, the program's development process, dissemination and impacts, and our future work.



At the STREET - Simulating Transportation for Realistic Engineering Education and Training website, we have a new model, ANGIE:

"The Agent-based Network Growth model with Incremental Evolution (ANGIE) models the growth of road networks in several scenarios such as road networks in an artificial grid-like city and the Minneapolis Downtown Skyway network. The philosophy inherent in these models is that accessibility affects road network growth and vice versa. The examples aim to illustrate that different values of accessibility at individual locations can lead to different network topologies."

The model is what we used on two papers:

We welcome feedback.

Up and Down the Ladder of Abstraction

Bret Victor of the Kill Math project has Up and Down the Ladder of Abstraction which uses a very simple driving simulator as an illustration. Everyone doing simulation or in transportation engineering education should read this.

How can we design systems when we don't know what we're doing?

The most exciting engineering challenges lie on the boundary of theory and the unknown. Not so unknown that they're hopeless, but not enough theory to predict the results of our decisions. Systems at this boundary often rely on emergent behavior — high-level effects that arise indirectly from low-level interactions.

When designing at this boundary, the challenge lies not in constructing the system, but in understanding it. In the absence of theory, we must develop an intuition to guide our decisions. The design process is thus one of exploration and discovery.

How do we explore? If you move to a new city, you might learn the territory by walking around. Or you might peruse a map. But far more effective than either is both together — a street-level experience with higher-level guidance.

Likewise, the most powerful way to gain insight into a system is by moving between levels of abstraction. Many designers do this instinctively. But it's easy to get stuck on the ground, experiencing concrete systems with no higher-level view. It's also easy to get stuck in the clouds, working entirely with abstract equations or aggregate statistics.

This interactive essay presents the ladder of abstraction, a technique for thinking explicitly about these levels, so a designer can move among them consciously and confidently.

I believe that an essential skill of the modern system designer will be using the interactive medium to move fluidly around the ladder of abstraction.

Mac|Life says: Cities in Motion Arriving for Mac Today

Paradox Interactive announced today that its mass transportation simulator, Cities in Motion, will be released for Mac today. If you've got a burning desire to design mass transit systems to get millions of people to work (or if you're just frustrated with your own city's transit system and want to show them how it's done) this ultra-nerdy simulation may be for you.

Developed by a new Finnish (as in: from Finland) development studio (Colossal Order,) Cities in Motion could probably just as easily been called Traffic Tycoon as its gameplay resembles that of other crowd simulations like Rollercoaster Tycoon. Though Cities in Motion is doubtlessly a cooler name.

The game has been available on PC since late February and has garnered a mixed bag of review scores averaging out to a Metacritic rating of 70 (relatively average for the video game section of Metacritic.) Though a mixed reception is all that can reasonably be expected for a modern day train set.

Anyone with experience on the game? Should I get?

Beyond the Beyond (Bruce Sterling) reports on Architecture Fiction: Pixel City - Procedurally generated city. I want to live here.

Some literature on procedurally generated networks (this city seems to be on a grid):

  • Guoning Chen, Gregory Esch, Peter Wonka, Pascal Mu ̈ller, Eugene Zhang (2008) "Interactive Procedural Street Modeling"

    This paper addresses the problem of interactively modeling large street networks. We introduce an intuitive and flexible modeling framework in which a user can create a street network from scratch or modify an existing street network. This is achieved through designing an underlying tensor field and editing the graph representing the street network. The framework is intuitive because it uses tensor fields to guide the generation of a street network. The framework is flexible because it allows the user to combine var- ious global and local modeling operations such as brush strokes, smoothing, constraints, noise and rotation fields. Our results will show street networks and three-dimensional urban geometry of high visual quality.

  • Carlos A. Vanegas, Daniel G. Aliaga, Bedrich Benes and Paul Waddell (2009) "Visualization of Simulated Urban Spaces: Inferring Parameterized Generation of Streets, Parcels, and Aerial Imagery". IEEE TRANSACTIONS ON VISUALIZATION AND COMPUTER GRAPHICS, VOL. 15, NO. 3, MAY/JUNE 2009.

    Urban simulation models and their visualization are used to help regional planning agencies evaluate alternative transportation investments, land use regulations, and environmental protection policies. Typical urban simulations provide spatially distributed data about a number of inhabitants, land prices, traffic, and other variables. In this article, we build on a synergy of urban simulation, urban visualization, and computer graphics to automatically infer an urban layout for any time step of the simulation sequence. In addition to standard visualization tools, our method gathers data of the original street network, parcels, and aerial imagery and uses the available simulation results to infer changes to the original urban layout. Our method produces a new and plausible layout for the simulation results. In contrast with previous work, our approach automatically updates the layout based on changes in the simulation data and, thus, can scale to a large simulation over many years. The method in this article offers a substantial step forward in building integrated visualization and behavioral simulation systems for use in community visioning, planning, and policy analysis. We demonstrate our method on several real cases using a 200-Gbyte database for a 16,300-km2 area surrounding Seattle.

  • Chao Yang, Peng Zeng and Yi Wang (2010) "Modeling the Evolution of Urban Road Networks: A case study on Pudong New Area in Shanghai" 2010 International Conference on Intelligent Computation Technology and Automation.

    Based on complex network theory, this paper proposes a topological evolution model for urban road network. The model also considers the external factors that affect network growth such as population density and economic index, which makes it flexible to adjust the influencing factors while for different types of networks. Furthermore, it’s feasible
    to visualize the differences with the real data in ArcGIS. Then, a case study of road network in Shanghai Pudong New Area is given, several common indicators are calculated. The results show good agreement between real data and model to verify the model is correct and valid.


Recently published:

Huang, Arthur and David Levinson (2011) Why retailers cluster: an agent model of location choice on supply chains volume 38(1) pages 82 - 94. [download from Environment and Planning b website]

Abstract. This paper investigates the emergence of retail clusters on supply chains comprised of suppliers, retailers, and consumers. An agent-based model is employed to study retail location choice in a market of homogeneous goods and a market of complementary goods. On a circle comprised of discrete locales, retailers play a noncooperative game by choosing locales to maximize profits which are impacted by their distance to consumers and to suppliers. Our findings disclose that in a market of homogeneous products symmetric distributions of retail clusters arise out of competition between individual retailers; average cluster density and cluster size change dynamically as retailers enter the market. In a market of two complementary goods, multiple equilibria of retail distributions are found to be common; a single cluster of retailers has the highest probability to emerge. Overall, our results show that retail clusters emerge from the balance between retailers' proximity to their customers, their competitors, their complements, and their suppliers.

The software underlying this paper, CLUSTER, has just been made available on the STREET website, so you are free to test and reproduce the results yourself. The software is free and open source, so feel free to modify, please let us know if you do anything.

David Levinson

Network Reliability in Practice

Evolving Transportation Networks

Place and Plexus

The Transportation Experience

Access to Destinations

Assessing the Benefits and Costs of Intelligent Transportation Systems

Financing Transportation Networks

View David Levinson's profile on LinkedIn

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