Publications

2015
Information diffusion through social networks: The case of an online petition
Jalali MS, Ashouri A, Herrera-Restrepo O, Zhang H. Information diffusion through social networks: The case of an online petition. Expert Systems with Applications. 2015;44 :187–197. Abstract

People regularly use online social networks due to their convenience, efficiency, and significant broadcasting power for sharing information. However, the diffusion of information in online social networks is a complex and dynamic process. In this research, we used a case study to examine the diffusion process of an online petition. The spread of petitions in social networks raises various theoretical and practical questions: What is the diffusion rate? What actions can initiators take to speed up the diffusion rate? How does the behavior of sharing between friends influence the diffusion process? How does the number of signatures change over time? In order to address these questions, we used system dynamics modeling to specify and quantify the core mechanisms of petition diffusion online; based on empirical data, we then estimated the resulting dynamic model. The modeling approach provides potential practical insights for those interested in designing petitions and collecting signatures. Model testing and calibration approaches (including the use of empirical methods such as maximum-likelihood estimation, the Akaike information criterion, and likelihood ratio tests) provide additional potential practices for dynamic modelers. Our analysis provides information on the relative strength of push (i.e., sending announcements) and pull (i.e., sharing by signatories) processes and insights about awareness, interest, sharing, reminders, and forgetting mechanisms. Comparing push and pull processes, we found that diffusion is largely a pull process rather than a push process. Moreover, comparing different scenarios, we found that targeting the right population is a potential driver in spreading information (i.e., getting more signatures), such that small investments in targeting the appropriate people have ‘disproportionate’ effects in increasing the total number of signatures. The model is fully documented for further development and replications.

    Information diffusion.pdf
    Three Essays on Systems Thinking and Dynamic Modeling in Obesity Prevention Interventions
    Jalali SMJ. Three Essays on Systems Thinking and Dynamic Modeling in Obesity Prevention Interventions. Virginia Tech Dissertations. 2015;
    Using the method of simulated moments for system identification
    Jalali MS, Rahmandad H, Ghoddusi H. Using the method of simulated moments for system identification. Analytical Methods for Dynamic Modelers. 2015;:39-69. MSM book chapter.pdf
    2014
    Dynamics of Obesity Interventions inside Organizations
    Jalali M, Rahmandad H, Bullock S, Ammerman A. Dynamics of Obesity Interventions inside Organizations. The 32nd International Conference of the System Dynamics Society. 2014;:69.
    How individuals weigh their previous estimates to make a new estimate in the presence or absence of social influence
    Jalali MS. How individuals weigh their previous estimates to make a new estimate in the presence or absence of social influence. International Conference on Social Computing, Behavioral-Cultural Modeling, and Prediction. 2014;:67-74. Abstract

    Individuals make decisions every day. How they come up with estimates to guide their decisions could be a result of a combination of different information sources such as individual beliefs and previous knowledge, random guesses, and social cues. This study aims to sort out individual estimate assessments over multiple times with the main focus on how individuals weigh their own beliefs vs. those of others in forming their future estimates. Using dynamics modeling, we build on data from an experiment conducted by Lorenz et al. [1] where 144 subjects made five estimates for six factual questions in an isolated manner (no interaction allowed between subjects). We model the dynamic mechanisms of changing estimates for two different scenarios: 1) when individuals are not exposed to any information and 2) when they are under social influence.

    Social influence on making estimations.pdf
    Public and health-professionals’ misconceptions about the dynamics of body weight gain/loss
    Abdel-Hamid T, Ankel F, Battle-Fisher M, Gibson B, Gonzalez-Parra G, Jalali M, et al. Public and health-professionals’ misconceptions about the dynamics of body weight gain/loss. System Dynamics Review. 2014;30 (1-2) :58–74. Abstract

    Human body energy storage operates as a stock‐and‐flow system with inflow (food intake) and outflow (energy expenditure). In spite of the ubiquity of stock‐and‐flow structures, evidence suggests that human beings fail to understand stock accumulation and rates of change, a difficulty called the stock–flow failure. This study examines the influence of health care training and cultural background in overcoming stock–flow failure. A standardized protocol assessed lay people's and health care professionals’ ability to apply stock‐and‐flow reasoning to infer the dynamics of weight gain/loss during the holiday season (621 subjects from seven countries). Our results indicate that both types of subjects exhibited systematic errors indicative of use of erroneous heuristics. Indeed 76% of lay subjects and 71% of health care professionals failed to understand the simple dynamic impact of energy intake and energy expenditure on body weight. Stock–flow failure was found across cultures and was not improved by professional health training. The problem of stock–flow failure as a transcultural global issue with education and policy implications is discussed. 

    misconceptions about obesity.pdf
    2012
    Establishing baseline electrical energy consumption in wood processing sawmills for lean energy initiatives: A model based on energy analysis and diagnostics
    Gopalakrishnan B, Mardikar Y, Gupta D, Jalali SM, Chaudhari S. Establishing baseline electrical energy consumption in wood processing sawmills for lean energy initiatives: A model based on energy analysis and diagnostics. Energy Engineering. 2012;109 :40-80.
    2011
    Development of an integrated model for process planning and parameter selection for machining processes
    Gupta DP, Gopalakrishnan B, Chaudhari SA, Jalali S. Development of an integrated model for process planning and parameter selection for machining processes. International journal of production research. 2011;49 :6301-6319.

    Pages