------------------- GENERAL INFORMATION ------------------- 1. Title of Dataset: SOUND – System for Ultraconnected Network Degeneration (with code to analyze network geometrics) 2. Authors: David Levinson, Feng Xie 3. Author contact: dlevinson@umn.edu 4. Date of data collection: 2008 5. Information about funding sources that supported the collection of the data: Study based upon work supported by the National Science Foundation under Grant No. 0236396 -------------------------- SHARING/ACCESS INFORMATION -------------------------- 1. Licenses/restrictions placed on the data: Attribution-Noncommercial-ShareAlike 3.0 United States (http://creativecommons.org/licenses/by-nc-sa/3.0/us/) 2. Links to publications that cite or use the data: Xie, Feng and David Levinson (2008) The Weakest Link: A Model of the Decline of Surface Transportation Networks. Transportation Research part E 44 100-113. Paper available at: University of Minnesota Digital Conservancy, http://hdl.handle.net/11299/179972. 3. Recommended citation for the data: Xie, Feng; Levinson, David M. (2016). SOUND – System for Ultraconnected Network Degeneration (with code to analyze network geometrics). Retrieved from the University of Minnesota Digital Conservancy, http://hdl.handle.net/11299/181333. --------------------- DATA & FILE OVERVIEW --------------------- This software models the economic mechanisms behind the decline of a surface transportation network, based on the assumption that the decline phase is a spontaneous process driven by decentralized decisions of individual travelers and privatized links. The software models a degeneration process by which the weakest link is removed iteratively from the network. Note: opening and running this program will require an environment that runs Java, such as Eclipse or Dr. Java, which can be downloaded freely. Instructions to run program: 1. Import all java files in the package into a Java platform, such as Eclipse or Dr. Java 2. Run "demo.java" as an applet, see 'Notes on SOUND' below. 3. On the left-bottom corner of the applet, input the name of a test file and click "Load" to load the file. The package includes four files for test, named "test-1","test-2","test-3","test-4", respectively.They are actually the files that store the results of running SOUND experiments,which record the information of network topology, speeds and volumes of each link at each round throughout the simulation of network growth. 4. After loading is completed, click ">" or "<" in the applet to examine the network structure at a specific iteration. Step size can be chosen from a dropbox. 5. At the same time, the measures of connection patterns of arterial links (in yellow) every 5 iterations have been printed out in the console window. 6. Note that "Batch" and "Evolve" will cause the program to cease working - "demo.java" loads test results, but does not compute them. Notes on SOUND: A class named "TopologyIdentifier" is embedded in "NetworkDynamics.java" to identify the predefined connection patterns of specified link types. Therefore, not all the files in the package are relevant to topology identification. For more details, refer to Xie, Feng and David Levinson (2006) Measuring the Structure of Road Networks. Geographical Analysis In the "TopologyIdentifier" class: Output() method calculates the structual measures of network topologies for specified iterations; identifySubgraph() identifies the unconnected pieces of arterials in a given network; identifyCircuitBlocks() identifies the circuit blocks in the network; identifyEnvelope() identifies the envelope of a given circuit block; bridge() identifies bridge links; articulation() identifies articulation points; decompose() decompose a network into components by removing bridges and articulation points. Refer to the notations in the codes for more details. Files included in the zipped folder: Automata.class BooleanStack.class Demo$DrawArea.class Demo$DrawPanel.class Demo$ScrollPanel.class Demo$VariablesPanel.class Demo.class DijkstrasAlgo.class DirectedGraph$ReadANumber.class DirectedGraph.class FloatStack.class IntStack.class Investment2.class MenuFrame.class NetworkDynamics$TopologyIdentifier.class NetworkDynamics.class Revenue.class TAssignment$Dimension.class TAssignment.class WindowDestroyer.class Automata.java BooleanStack.java Demo.java DijkstrasAlgo.java DirectedGraph.java FloatStack.java IntStack.java Investment2.java MenuFrame.java NetworkDynamics.java Revenue.java TAssignment.java WindowDestroyer.java Batch.txt cGrid_4.txt cGrid_5.txt Grid10.txt Grid100.txt Grid15.txt Grid20.txt Grid5.txt Grid_3.txt Grid_4.txt Grid_5.txt hexagon_15.txt iGrid_15.txt iGrid_20.txt iGrid_25.txt Readme.txt test-1.txt test-2.txt test-3.txt test-4.txt -------------------------- METHODOLOGICAL INFORMATION -------------------------- From page 107 of Xie, Feng and David Levinson (2008) The Weakest Link: A Model of the Decline of Surface Transportation Networks. Transportation Research part E 44 100-113. Paper available at: University of Minnesota Digital Conservancy, http://hdl.handle.net/11299/179972" "A series of five experiments were carried out on a hypothetical surface transportation network with the same initial conditions, including the same set of link speeds randomly distributed between 1 and 10, and the same set of uniform land uses (resulting in 10 trips generated from and 10 trips attracted to each cell per day). The hypothetical network is called the 4 · 4 complete network, which is developed by directly connecting every pair of two nodes among an original node set {V*} that come from the intersection nodes of a 4 · 4 grid network. When links intersect, a new secondary node is created, and the longer link is replaced by shorter links that ultimately connect the same original nodes. A secondary node is not necessarily directly connected to an original node or another secondary node. Where links overlap, the longer link is eliminated. A complete network represents a highly redundant network that is expected to decline over time."