Welcome

Welcome to the site for the creation of Scientific Papers with Open Communication at the Center for the Study of Complex Systems from the University of Michigan. Increasingly, scientists from across disciplines rely on computational models to build deeper understanding and better intuitions about the behavior and dynamics of complex systems. The widespread use of computational models has not been paralleled by adjustments in the traditional formats and venues for scientific communication, i.e., papers in hardcopy journals and books. At this site, we provide the computational and social infrastructure to support the use of a new form of scientific communication called a SPOC (Scientific Paper with Open Communication). Here, we can keep a permanent and accessible public record of the computational models developed throughout modern science. You are encouraged to browse our database of models, download them, provide comments on them, and upload your own models.

Latest SPOCs

AdaGEP - An Adaptive Gene Expression Programming Algorithm

Keywords: adaptive, genemap, GEP
Requirements: ECJ16, Java
Confirmations:
  • I ran and replicated results: 0
  • I ran, but could not replicate results: 0
  • I installed, but could not run: 0
  • I could not install: 0
ID:
SPOC-CSCS-2008-08-25-001
Authors:
Elena Băutu
Authors:
Andrei Băutu
Authors:
Henri Luchian

Many papers focused on fine-tunning the Gene Expression Programming (GEP) operators or their application rates in order to improve the performances of the algorithm. Much less work was done on optimizing the structural parameters of the chromosomes (i.e. number of genes and gene size). This is probably due to the fact that the No Free Lunch theorem states that no fixed values for these parameters will ever suit all problems. To counteract this fact, this paper presents a modified GEP algorithm, called AdaGEP, which automatically adapts the number of genes used by the chromosome.

Searching Ground States of Ising Spin Glasses with Particle Swarms

Requirements: Matlab
Confirmations:
  • I ran and replicated results: 0
  • I ran, but could not replicate results: 0
  • I installed, but could not run: 0
  • I could not install: 0
ID:
SPOC-CSCS-2008-08-25-001
Authors:
Andrei Băutu
Authors:
Elena Băutu

This paper presents a method for searching ground states of Ising spin glasses. The Ising model is one of the most commonly used because of its simplicity and its accuracy in representing real problems. We tackle the problem of finding ground states with particle swarm optimization (PSO), a population-based stochastic optimization technique inspired by social behavior of bird flocking.

Gene Expression Programming for Fredholm first kind integral equations occurring in synthesis of electromagnetic fields

Requirements: Java
Confirmations:
  • I ran and replicated results: 0
  • I ran, but could not replicate results: 0
  • I installed, but could not run: 0
  • I could not install: 0
ID:
SPOC-CSCS-2008-08-25-001
Authors:
Elena Băutu
Authors:
Elena Pelican

It is known that Fredholm integral equations of the first kind occur when solving with problems of synthesis of electrostatic and magnetic fields. This paper presents two approaches for solving such an equation. The first one involves discretization by a collocation method and numerical solution using an approximate orthogonalization algorithm. The second method is based on a nature inspired heuristic, namely genetic programming.

Simple Food Web with Agent and Equation Based Models

Keywords: food web, population
Requirements: Java, Repast
Confirmations:
  • I ran and replicated results: 0
  • I ran, but could not replicate results: 0
  • I installed, but could not run: 0
  • I could not install: 0
ID:
SPOC-CSCS-2008-04-24-001
Authors:
Geoff Michael
Analysis of Lotka Voltera population equations indicates that complex food webs should be unstable and predicts the presence of fewer species than are observed in real food-webs. The question of diversity verses stability has been partially resolved by including spatial and temporal heterogeneity. This model simultaneously compares an ABM of multi-species agents with a simple equation-based model. A heterogeneous “landscape” can change the interactions between agents, and a refugia provides an area where the predator species is excluded.

Cognitive Redeployment in ACT-R: Salience, Vision, and Memory

Requirements: CCMSuite, Python
Confirmations:
  • I ran and replicated results: 0
  • I ran, but could not replicate results: 0
  • I installed, but could not run: 0
  • I could not install: 0
ID:
SPOC-CSCS-2007-07-25-000
Authors:
Terrence C. Stewart
Authors:
Robert L. West
Cognitive redeployment is the idea that an important part of the evolution of cognition is the adaptation and re-use of existing cognitive modules for new purposes. Here, components of the ACT-R cognitive architecture are repurposed to develop novel models. In particular, the decelarative memory system is used to create a new vision system, and the salience system from ACT-R vision is integrated with declarative memory to produce a novel explanation for the release from proactive interference effect.

Latest MOREs

The El Farol Problem

Requirements: Java
Confirmations:
  • I ran and replicated results: 1
  • I ran, but could not replicate results: 0
  • I installed, but could not run: 0
  • I could not install: 0
ID:
MORE-CSCS-2008-08-13-001

This MORE explores economic decision making without perfect rationality.  The model is concerned with 100 patrons who wish to attend a bar on the same night without overcrowding it.  Each patron must decide whether to attend or not based on limited information (the past history of attendance).

A Model of Norm Entrenchment

Requirements: Eclipse, Java
Confirmations:
  • I ran and replicated results: 1
  • I ran, but could not replicate results: 0
  • I installed, but could not run: 0
  • I could not install: 0
ID:
MORE-CSCS-2008-07-21-001

 This MORE is an implementation of Epstein's (2001) "Learning to be Thoughtless: Social Norms and Individual Computation", which presents a model wherein agents adopt behaviors by copying the majority of their neighbors and by assessing diversity in the proportion of neighbors around them.  As a norm becomes more entrenched, i.e., more and more agents adopt it, the less any particular agent re-samples to assess whether it ought to modify its own behavior.

A Model of Conformity and Consistency

Requirements: Java
Confirmations:
  • I ran and replicated results: 1
  • I ran, but could not replicate results: 0
  • I installed, but could not run: 0
  • I could not install: 0
ID:
MORE-CSCS-2008-06-11-001

This is an implementation of a model of conformity and consistency developed by Bednar, et. al.

Simple Growth Model

Confirmations:
  • I ran and replicated results: 0
  • I ran, but could not replicate results: 0
  • I installed, but could not run: 0
  • I could not install: 0
ID:
MORE-CSCS-2007-09-08-001

Replication of some of the results of Alfred Hubler's paper, "Predicting Complex Systems with a Holistic Approach."

Building New Political Actors (The Tribute Model)

Requirements: Linux, Repast 3.1
Confirmations:
  • I ran and replicated results: 0
  • I ran, but could not replicate results: 0
  • I installed, but could not run: 0
  • I could not install: 0
ID:
MORE-CSCS-2007-08-16-001
This is a RepastJ implementation of Robert Axelrod's Tribute Model.