Analytics-based solutions for healthy and sustainable cities
In an era where people health has been unjustly impacted by their income, age, gender, education, ethnicity, and socioeconomic status, programs like the Recreovía and the Ciclovía Recreativa serve the entire community regardless of any of these factors with a health-focused approach. Accordingly, the necessity to bring healthy living into people’s daily lives has been and will continue to be a significant challenge for public health practitioners and city officials. This challenge inevitably involves assigning resources innovatively and efficiently using analytics-based techniques towards the goal of having healthier and sustainable cities.
See the video of the RecreoBOG project
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Contact: Andrés L. Medaglia
Related work and links:
- EpiAndes research group at Universidad de los Andes.
- Medaglia, A. L. (2017). Promoting health and wellness through OR. In IFORS News. OR-Impact Section. 11(4). ISSN: 2223-4373
- IFORS Prize for Operations Research (OR) in Development (2017). 21th Conference of the International Federations of Operational Research Societies (IFORS). Quebec City (Canada) .
- Abolghasem, S., Solano, F., Bedoya, C. D., Navas, L.P., Ríos. A. P., Pinzón. E. A., Medaglia, A. L., Sarmiento, O. L. (2018). A robust DEA-centric location-based decision support system for expanding Recreovía hubs in the city of Bogotá (Colombia). International Transactions in Operational Research.
- Abolghasem, S., Gómez-Sarmiento, J., Medaglia, A. L., Sarmiento, O. L., González, A. D., Díaz del Castillo, A., Rozo-Casas, Juan F., Jacoby, E. (2018). A Data Envelopment Analysis (DEA)-centric decision support system for evaluating Ciclovía-Recreativa (CR) programs in the Americas. Socio-Economic Planning Sciences. 61:90–101.
- Sefair, J. A., Molano, A., Medaglia, A. L., and Sarmiento, O. L. (2011). Locating neighborhood parks with a lexicographic multiobjective optimization method. In Community-Based Operations Research: Decision Modeling for Local Impact and Diverse Populations. Michael P. Johnson (Ed.). International Series in Operations Research & Management Science, Volume 167, Part 2, 143-171.
Improving harvesting operations in an oil palm plantation
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Oil palm agricultural systems involve large extensions of land that demand careful planning of the harvesting operations. The plantation manager is in charge of synchronizing resources (i.e., crews and a complex cableway network) to harvest at the right time to maximize palm oil yield in latter stages of the value chain. In particular, in this type of crop it is ideal to visit each palm every eight to ten days to avoid loose fruit picking, over-ripeness, or rotten fruit harvesting. To optimize harvest operations, we propose an end-to-end analytics solution involving data treatment, predictive, and prescriptive models (optimization and simulation) in this agricultural system. At the core of our approach lies a set of interconnected models that use optimization, heuristic techniques, and simulation. These models cover strategic (harvest cycle), tactical (resource allocation), and operational (transport allocation) decisions. The results show a strong potential for improving yield by adjusting the harvest cycle length from 19.6 to 8.3 days in a 2000-hectare plantation located in the Colombian Orinoquia. This is a joint research collaboration with the Centro de Estudios de la Orinoqia (CEO).
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Contact: Andrés L. Medaglia
Contributions of multi-objective optimization techniques to maximize thermal stability and strength of materials obtained by machining
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The microstructure of pure Copper processed by machining manufacturing process such as turning and milling is explored with the aim to create highly refined grain structures to achieve the highest strength while postponing the potential possibilities for future recrystallization which inherently lead to non-thermally-stable materials. These two targeted properties are often conflicting requirements: an improvement in one (strength) generally leads to a deterioration in the other (thermal stability). Hence, it is not straight forward to follow a procedure that would set both the properties at their individual best: all that can be achieved is a tradeoff, a compromise between the two objectives. Here we attempt to obtain a set of optimum solutions using multi-objective optimization algorithms as well as the Kuhn-Tucker optimality conditions. Additionally, we verify the solution empirically by creating the sample condition. The resulting microstructure is characterized via electron microscopy confirming the theoretical result. The thermal stability of the optimal solution is verified as well. Finally, we studied the kinetics of crystallization on the optimal solution using the Johson–Mehl–Avrami–Kolmogorov (JMAK) theory.
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Contact: Sepideh Abolghasem
Statistical modeling of materials microstructure in machining-based manufacturing processes
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Capturing microstructure evolution in machining experiments such as turning and milling can help in controlling and predicting materials responses as well as the final properties of the engineering metallic components. We examine different metallic materials through machining. The cutting conditions are characterized and the microstructure characteristics are quantified utilizing orientation imaging microscopy (OIM). Finite element models are performed to obtain the central machining conditions for various ranges of paramters. We develop models to study microstructure transformations via two approaches. The first one develops statistical mappings between the machining parameters and the microstructural characteristics. We perform a particular designed experiments method seeking a linear mixed-effects model for the two principal machining parameters, cutting angle and the velocity. The statistical model is applied to identify the factors that most significantly contribute to variability in the mean grain size and orientation angle among the gains. The second approach incorporates the effect of cutting tool edge radius using functional regression method. Building on this, the model estimates the final grain size given the distribution of the tool edge radius. . The premise of the ongoing research is that machining under realistic conditions is characterized by a stochastic system wherein the temporal evolution of the tool-tip geometry and the distributions of the bulk microstructure would interact in complex ways, while leading to the evolution of final microstructures. Identifying this evolution would likely involve a Bayesian framework to link the effect of tool-wear to the modification of machining conditions.
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Contact: Sepideh Abolghasem
Business Process Modeling as Complex Networks
In this early stage Project we want to translate the BPM notation into graph language in order to perform structural analysis of business processes together with classical functional analysis from Operations Research. The process network metrics will help us to the process analysis and optimization:
- Graph diameter: the maximum number of activities that must be carried out to end the processes.
- Shortest path: the minimum number of activities that must be carried out to end the processes.
- Average path length and clustering coefficient can give information about the parallelization and recursion degree of the processes.
- Indegree and Outdegree of the process components, identify the process sources and sinks, the ration between them influence the process controllability.
- Hubs: Critical activities.
- Clusters: Sets of very interrelated activities, will possible coincide with the designed process and can be used as a process design assessment tool.
- Structural attacks: removing critical activities would make the process collapse? Measure robustness of the process.
Corporate Sustainability World Map
The General Reporting Initiative (GRI) is the standard for Corporate Sustainability Reporting. The relations for a set of global enterprises interrelationships are built with the Mutual Information (MI) between enterprises (GRI) reporting data. We describe the enterprises interrelation from the MI topology using chord diagrams to represent the inter and intra connectivity between geographical regions and economic sectors globally, by continents and countries. Detailed maps are presented for Europe and Asia regions/sectors as well as the relationship for Europe and Asia top reporting countries. Our findings reinforce previous research about the role of Europe as a driver of sustainability and its influence worldwide. The GRI maps outline the behavior of the involved economic sectors, for all the studied regions. Also, a measure relating the inter to intra connections is presented in order to describe the relationship inside and between regions/sectors.
In the image below you can appreciate a schematic representation of the GRI network and identified clusters at microscopical level of enterprises. Human society is “good” at clustering, at right you see a geographical representation of the GRI map at continent scale. We can study the system inter and intra relations at different scales, continents, regions, countries.
Mapping the Global Offshoring Network through the Panama Papers
The aim is to map the offshoring network between regions and countries worldwide through the Panama Papers. The Panama Papers 2016 divulgence is the largest leak of offshoring and tax avoidance documentation. The leaked documents contain 2.6 Terabytes of information involving more than two hundred thousand of enterprises in more than two hundreds countries. Using the Offshore leaks database (https://offshoreleaks.icij.org) we related entities around the world through different types of relationships. These relationships were used in order to build an offshoring network at countries and geographical regions scales. The network will be characterized and described to map the intra and inter relation between the countries and regions, discovering which of them are the more prominent in the worldwide offshoring scenario.
Image: https://offshoreleaks.icij.org
Understanding Complexities and Making Predictions in Socio-Economic Systems
These research projects are aimed to use a socio-physics modeling approach applied to areas that are considered discrete disciplines (sociology, economics, politics, etc.). These social systems will be modeled and analyzed focusing on how the structure of ties affects and constitutes actors (individuals/enterprises) and their relationships. Mainly, graph theory and complex network analysis will be used to describe the actors relationship connectivity. We will describe the a variety of systems, going from data to networks in order to analyze the structure and interactions of the actors in these systems. We will approach:
LGBT regulations evolutions.
Gender Equality regulations evolution.
Corruption data (Transparency International).
Open Government Data (Colombia) to model and support public programs and policy.
Ensemble learning using Attractor Neural Networks
One of the main trends of research in Machine Learning, along with “deep learning”, is the study of “networks of networks”. One central question of interest is comparing a net of nets with overall connectivity of similar degree with only one single net with the same size and check their different performances in terms of storage/load, computational complexity, etc. Attractor networks as associative memory models have many desirable properties. As dynamical systems and associative memory systems the attractor networks can be used as denoising and pattern completion. They have been used in neuroscience to model for example spatial working memory and in Engineering applications such as fingerprint recognition and automotive traffic content retrieval systems. However, one of their drawbacks is limited capacity of storage. Using an Ensemble of diluted Attractor Neural Networks for pattern retrieval we have increased the network storage capacity by a divide-and-conquer approach of subnetworks. With the Ensemble approach we can deal with Engineering applications to limited memory systems: embedded systems or smartphones. Also, applications with intensive storage needs can be approached.
