Don’t dope – run the code!

By Andrey Krasovskii, IIASA Ecosystems Services and Management Program

During his workout in the IIASA gym, my colleague Pekka Lauri often runs on a treadmill. He adjusts the velocity of running using the control panel, and it indicates the distance and approximate calories burnt. While Pekka may not be thinking about mathematical models during his workout break, running and other athletic performance can be modeled using some of the same techniques that we use for other questions at IIASA.

Outside of my academic work at IIASA, I am highly interested in sports, and athletics in particular. My wife, Katy Kuntsevich, has won Austrian championships in high jump several times, and my brother, Nikolay, was on his university team as a 400 meter runner.

Visiting my hometown Ekaterinburg, Russia, back in 2014, I got into a dispute with my father, who is a university professor in theoretical mechanics. Namely, my argument was that the sprinters’ acceleration at the finish line of the 100 meter race should be negative. Later on, during the Christmas holidays, I decided to mathematically support my statement.

Left: Prof. Krasovskii with a page from his Lectures in Theoretical Mechanics (Chapter 2, Kinematics, in Russian) featuring Valeriy Borzov on finish. This page was a reason for my study. Top right: Portrait of Isaac Newton.

Left: Prof. Krasovskii with a page from his Lectures in Theoretical Mechanics (Chapter 2, Kinematics, in Russian) featuring Valeriy Borzov on finish. This page was a reason for my study. Top right: Portrait of Isaac Newton.

When athletes run a race, their horizontal velocity can be estimated by modern technologies such as high resolution cameras and lasers. Knowing the horizontal instantaneous velocity, one can calculate acceleration. According to Newton’s law, one can introduce the forces applied to the body center mass of the athlete. Outside a gym treadmill it gets a bit more complicated, with air resistance and headwind or tail-wind. Against these aerodynamic forces the runner applies horizontal force, which drags him forward. In reality it is an “aggregate” of impulsive normal forces generated by feet and the stroke frequency.

The dynamics of an athlete have been described by an ordinary differential equation studied in papers on sprint modeling, first published by physicist J. Keller. This equation has been considered in numerous papers, which have shown that the equation fits the real data for short-distance running (100 and 200 meters). The indicated studies are devoted to the calibration of parameters, to the wind impact analysis, and to the choice of force functions such that the solution satisfies the actual motions, e.g. the running records of Usain Bolt.

The problem of running dynamics reminded me of a type of model that we sometimes use at IIASA, called an optimal control model. Optimal control models are used to calculate the best or most efficient way of doing something, for example, driving from one place to another. If I want to drive from Vienna to Laxenburg, I start my car’s engine at my house (point A). I look at the time, and plan to arrive to IIASA (point B) in 30 minutes. In optimal control terms, the car is a control object, and the driver controls it by pushing the gas/brake pedals and steering the wheel. In the driving process the car meets certain constraints (e.g. the engine power, available roads, and speed limits) and disturbances (e.g. traffic jams, lights, and weather conditions). Obviously, there are many ways of controlling the car in order to reach IIASA in 30 minutes. What if among those admissible controls, I wanted to find an optimal control minimizing car’s energy expenditures during the 30-minute trip from A to B? Here energy is an intensity (cost) of control actions, i.e. fuel (petrol/electricity), or corresponding greenhouse gas emissions. Well, in this case one needs to solve the classical minimum energy control problem. The solution to this problem gives an optimal plan that the car driver (or autopilot) needs to implement. Note, that the corresponding time-optimal control problem consists in finding the fastest driving time to IIASA under given fuel reserve. Optimal control theory (OCT) is an efficient tool for solving such dynamic optimization problems.

My research question was: “Can one control his/her running similar to driving a car?” The answer is: “Yes!”

I applied an optimal control model to Usain Bolt’s performance data at the Beijing Olympic Games in 2008, when he ran the 100 meter sprint in 9.69 seconds. According to the model, under the same conditions he could have distributed his energy optimally and run the distance in 9.56 s. It is worth mentioning that this time is close to his current world record, 9.58 s, achieved at the 2009 World Championships in Berlin. In the paper I also provide modeling results for optimal (energy-efficient) running over 100 m: calculation of the minimum energy and trajectories of acceleration, velocity, and distance from start.

In the conclusion, I argue that applying advanced science in the athletic training programs is far better than doping–better in terms of a healthy body, mind and soul.

Here is my hypothesis of what Usain Bolt is doing at his laptop. © Weltklasse Zürich - Marcel Giger

Here is my hypothesis of what Usain Bolt is doing at his laptop. © Weltklasse Zürich – Marcel Giger

Reference:
A. A. Krasovskii, “Application of optimal control to a biomechanics model”, Proceedings of the Steklov Institute of Mathematics, 2015, Vol. 291, pp. 118–126. http://dx.doi.org/10.1134/S0081543815080118

 

I would like to thank Sergey Aseev, Katherine Leitzell, as well as my colleagues in the IIASA Ecosystem Services and Management Program (ESM) for their interest and valuable discussions.

 

Note: This article gives the views of the author, and not the position of the Nexus blog, nor of the International Institute for Applied Systems Analysis.

This summer in Moscow: Impressions from Moscow Summer Academy 2015

By M. Nazli Koseoglu, MSA 2015 Participant, School of Geosciences, Environmental Economics, Edinburgh University, Scotland

M. Nazli Koseoglu

M. Nazli Koseoglu

The Summer Academy on Economic Growth and Governance of Natural Resources took place at Lomonosov Moscow State University from 20th July to 1st August 2015.

As an environmental economist working on economic valuation and optimisation of water use, the academy was very interesting for me. Water management is a dynamic process and requires bringing perspectives and expertise from different disciplines together. Application of systems analysis enables us to combine aspects from various domains, come up with models that identify nonlinearities, project regime shifts, and tipping points in the management of water as well as other natural resources. Such projects require interdisciplinary collaboration and communicable results to inform policy. Scientists need to translate their results to a language accessible to the policymakers, in order for society to pick up on and capitalize on the research efforts. The MSA 2015 provided me with necessary training to go deeper into different modelling methodologies, and learn the concepts and principles of science for policy first-hand from IIASA scientists.

The reading list sent before the course gave me the impression that I would probably be the only environmental economist amongst a crowd of mathematical modellers. However, arriving in Moscow, I found that the MSA 2015 participants came from a broad range of backgrounds and countries at different stages of their careers in academia or policy. We all came  to learn and discuss the natural resource constraints to infinite economic growth on finite planet.

During lectures, the theoretical foundations of different mathematical approaches such as dynamical systems theory, optimal control theory and game theory were presented by leading scientists, such as Michael Ghil. Fundamentals of addressing challenges of natural resource management and comparing contemporary models of economic growth were also covered as central themes.

The course acknowledged the issues related with ecosystems services, public goods, inter-generational and international fairness, and public and common pool resource dynamics in the face of economic growth and resource constraints. The training underlined feedbacks between institutional dynamics and resource dynamics in complex social-ecological system and need for interdisciplinary and policy-relevant research, an important take-home message for next generation scientists.

Photos by M. Nazli Koseoglu

Photos by M. Nazli Koseoglu

What makes the MSA so special?
Apart from lectures, we had tutorials, a group project, poster and project presentation sessions, as well as interesting talks on IIASA activities by Margaret Goud-Collins and Elena Rovenskaya, and an inspiring session on the importance of finding the right mentor for a successful career by Prof Nøstbakken. The  MSA 2015 program had a good balance of theory and practice, which encouraged participants to be proactive and engaged.

I particularly liked the poster session. We presented our ongoing projects and received feedback from the lecturers and other participants. It was great to get comments and perspectives that I never thought of, and tips from senior researchers. In the late days of the academy we were assigned to prepare a group project on Artic systems which allowed us to put what we had learned at the lectures into practice and apply important topics outside our exact fields of study; in my case, these topics were petroleum economics and artic futures. I found the multi-disciplinary group work to be a great exercise for the development of my current study.

Attending the MSA 2015 provided useful training, both theoretical and practical, for understanding systems analysis approaches better. The host institution and organizing committee at Lomonosov Moscow State Univesrity provided impeccable hospitality, and the setting, in a landmark building in a landmark city, was a great perk. I received very constructive feedback, and made good connections around the world. I would recommend all early-career researchers in relevant fields to take this great opportunity next summer!

More information about MSA 2015

Participants in the MSA 2015. Photo Credit: M. Nazli Koseoglu

Participants in the MSA 2015. Photo Credit: M. Nazli Koseoglu

Note: This article gives the views of the author, and not the position of the Nexus blog, nor of the International Institute for Applied

Systems Analysis.

 

Flourishing within limits to growth

By Brian Fath, IIASA Advanced Systems Analysis Program and Towson University

Brian Fath. © Matthias Silveri | IIASA

Brian Fath. © Matthias Silveri | IIASA

The seminal book The Limits to Growth by Donella Meadows and colleagues was a first attempt to make a world model that integrated environment, economics, population, and industrial pollution. Without drastic changes to curb human population growth, consumption of non-renewable resources and industrial effluence, the model scenario projected a collapse of the world social-industrial system, because physically it is not possible to keep growing on a finite planet.  This important message spurred many people in the environmental sciences, but was largely ignored, or worse ridiculed, by the dominant economic and political leaders.  Perhaps their work was too pessimistic (although some could say realistic) and called for change for which society was not yet ready.

My co-authors and I  feel their message was interpreted incorrectly.  The restrictions imposed by The Limits to Growth do not entail stagnation and strife but rather give us an opportunity for new priorities, greater equity, and greater well-being.  Living within the limits can offer agreeable, pleasant, even thriving and wonderful living conditions.

Therefore we have written a book, which shows that following nature provides guidance and pathways to Flourishing within Limits to Growth.

People today are confronted with a number of very serious problems: poverty, increased inequalities among countries and people, refugees, regional conflicts and civil wars, global climate change, accelerating exploitation of the global non-renewable and renewable resources, rapid land use change and urbanization, and increased emissions of harmful chemicals into the environment. History has shown us that we cannot solve these problems using traditional methods based on short-sighted economic growth.

Additionally, we know from natural laws that continuous growth in a finite environment is not possible. How can we ensure sustainable development for society on Earth? It would be possible by imitating the system that understands how to sustain long-term development: to learn from nature and follow nature’s way. Nature shifts from quantitative biomass growth when the resources become limiting to qualitative development by increasing resource use efficiency, in terms of both improved network connectivity and information on process regulation and feedbacks. The two main ecosystem functions, flow of energy and transfer of nutrients, are accomplished by renewable energy and complete recycling of the needed elements.  Nature also originated and perfected the use the 3Rs: Reduce, Reuse, and Recycle.

“The restrictions imposed by The Limits to Growth do not entail stagnation and strife but rather give us an opportunity for new priorities, greater equity, and greater well-being" Innsbruck Austria - architecture and nature background. ©Nikolai Sorokin | Dollar Photo Club

“The restrictions imposed by The Limits to Growth do not entail stagnation and strife but rather give us an opportunity for new priorities, greater equity, and greater well-being” Photo: Innsbruck, Austria ©Nikolai Sorokin | Dollar Photo Club

Our book employs a global model to experiment with applying these properties of nature in society. Using global statistics, the model considers how the development will change if:

  • A revenue-neutral, resource-based Pigovian tax is increased significantly and along with commensurate tax reduction to enhance recycling and application of renewable energy
  • We increase investment in education, innovation, and research significantly to raise the level of understanding by the population and to develop new progressive ideas to address our global problems.
  • We increase pollution abatement considerably to reduce its negative impacts on our health, nature, and production.
  • We increase aid from the developed to the developing countries to 0.8% of GNP, which would enhance the cooperation among countries, reduce poverty and population growth and thereby also the number of refugees. In this context, it is important that the aid is given as support to education, health care, and family planning and not at all as military aid.

flourishingbookThe model calculations show that it is possible to obtain a win-win situation, where both industrialized and developing nations can achieve a better standard of living – the developing countries mostly quantitatively and the developed countries mostly qualitatively. The calculations are compared with scenarios based on “business as usual” practices. The business as usual scenario shows a major collapse around the year 2060, which is in accordance to the Limits to Growth results from 1972 and the follow-up-publications from the Club of Rome.

Furthermore, the book demonstrates calculations of ecological footprints and sustainability by assessing our consumption and loss of work energy due to our use of resources and destruction of nature. These calculations lead to the following conclusions:

  • Maintain natural areas and the ecosystem services they provide.
  • Improve agricultural production by increasing efficiencies and technologies.
  • Shift our thoughts and actions from quantitative growth to qualitative development, for instance by using the three R’s.
  • Shift to renewable energy.
  • Leave today’s policy focused entirely on short-sighted economic considerations and start to discuss how we can improve environmental management, increase the level of education and research, and achieve greater equality in society.
  • Develop and promote alternative measures of welfare and well-being.
  • Reduce, rather than reward, financial speculations, exorbitant profits, and stock market gambling.

More information: Listen to an interview with Brian Fath on WCBN Radio.

References
Jørgensen SE, Fath BD, Nielsen SN, Pulselli F, Fiscus D, Bastianoni S. 2015. Flourishing Within Limits to Growth: Following nature’s way. Earthscan Publisher.

Meadows, DH, Meadows, DL, Randers J., Behrens, W.H.  III, (1972) Limits to Growth, New York: New American Library.

Note: This article gives the views of the author, and not the position of the Nexus blog, nor of the International Institute for Applied Systems Analysis.

A new vision of Trans-Eurasian transportation

By Katherine Leitzell, IIASA Science Writer and Press Officer

The Trans-Siberian Railway is the longest railway in the world, connecting Moscow with Vladivostok and the Sea of Japan. Built at the turn of the 19th century, the railroad network connected remote Eastern Russia with the rest of the country, and created the first overland link between Europe and Asia.

In a meeting last week at IIASA, Russian researcher Yury Gromyko presented an equally ambitious transportation “megaproject” for the next century: the Trans-Eurasian Belt of Razvitie (Development in Russian), or the TEBR. The project, led by a group of leading Russian intellectual centers, would provide a new transportation network between markets in Europe and Asia, including high-speed rail, roads, as well as infrastructure such as pipelines and telecommunications networks.

Maglev trains, like this one in Shanghai, would be one component of the envisioned TeBR project. © 06photo | Dreamstime.com

Maglev trains, like this one in Shanghai, would be one component of the envisioned TEBR project. © 06photo | Dreamstime.com

Yet in Gromyko’s view the TEBR is also a development project that would bring new opportunities for trade and employment to the entire corridor of the construction. Gromyko described the project as a “New Future Zone,” which could revolutionize trade and economic development across Eurasia.

If the TEBR succeeds, Gromyko envisions new networks of smart cities in eastern Russia based on innovative technologies and new industries that would stem the tide of migration towards Moscow, instead pulling a new generation eastwards. “We need millions of young people to move to the Russian Far East. To attract them, there would need to be exciting jobs and affordable housing,” said Gromyko.

Gromyko presented the project at a workshop entitled, Development of Transport and Infrastructure in Eurasia. The meeting brought together transportation experts from across Eurasia to discuss visions for future development of the continent, and the key role of a multi-infrastructure approach in that development. Multi-infrastructure presupposes integration of different infrastructures from transportation to energy and telecommunications.

“Transportation and infrastructure are simply integral to economic development,” explains Michael Emerson, a senior researcher in the project who splits his time between the Centre for European Policy Studies (CEPS) and IIASA. “You cannot have one without the other.”

Credit: Russian Academy of Sciences

Credit: Russian Academy of Sciences

The event was the 5th in a series of scoping workshops arranged as part of the IIASA-coordinated project, Challenges and Opportunities of Economic Integration within a wider European and Eurasian Space, following previous workshops focused on research methodology, trade policy, non-tariff barriers, and energy. In addition to transportation and infrastructure projects, participants discussed investment and finance options for such major international efforts, as well as the challenges and opportunities of drawing private investment for long-term investments in infrastructure.

Several more scoping workshops are planned on different dimensions related to economic regional integration, explained project leader Elena Rovenskaya, the director of IIASA’s Advanced Systems Analysis Program. They create the foundation for the research phase involving researchers, business leaders, and policymakers from across Eurasia.

More information
Project: Challenges and Opportunities of Economic Integration within a Wider European and Eurasian Space 

Note: This article gives the views of the author, and not the position of the Nexus blog, nor of the International Institute for Applied Systems Analysis.

Network science and marketing: A virus’ tale

By Matthias Wildemeersch,  IIASA Advanced Systems Analysis and Ecosystems Services and Management Programs

FotoQuest Austria is a citizen science campaign initiated by the IIASA Ecosystems Services & Management Program that aims to involve the general public in mapping land use in Austria. Understanding the evolution of urban sprawl is important to estimate the risk of flooding, while the preservation of wetlands has important implications for climate change.

But how can we engage people in environmental monitoring, in particular when they are growing increasingly resistant to traditional forms of advertising? Viral marketing makes use of social networks to spread messages, and takes advantage of the trust that we have in the recommendation coming from a friend rather than from a stranger or a company.

Network science and the formal description of spreading phenomena can shed light on the propagation of messages through communities and can be applied to inform and design viral marketing campaigns.

Viral spreading © kittitee550 | Dollar Photo Club

Viral spreading © kittitee550 | Dollar Photo Club

Network science is a multi-disciplinary field of research that draws on graph theory, statistical mechanics, inference, and other theories to study the behavior of agents in various networks. The spreading phenomena in viral marketing show similarities with well-studied spreading processes over biological, social, physical, and financial networks. For instance, we can think about epidemics,which are well understood and allow for the design of optimal strategies to contain viruses. Another example is opinion dynamics, which received renewed research attention over the last years in the context of social media.  In contrast to diseases or computer viruses, which we aim to contain and stop, the goal of viral marketing is to spread widely, reaching the largest possible fraction of a community.

What makes viral marketing unique?
But some aspects of viral marketing are very different from what we see in other spreading phenomena. First of all, there are many platforms that can be used to spread information at the same time, and the interaction between these platforms is not always transparent. Human psychology is a crucial factor in social networks, as repeated interaction and saturation can decrease the willingness to further spread viral content. Marketing campaigns have a limited budget, and therefore it is meaningful to understand how we can use incentives and how efficient they are. This also means that it is essential to find the group of most influential people that can be used as seeds for the viral campaign.

Network science has addressed to a great extent all these individual questions, mostly under the assumption of full knowledge of the connections between the agents and their influence. Currently, so-called multiplexes are an active research field that studies the behavior of multi-layer networks. This research unveils the relationships between the dynamics of viral marketing, the connection pattern, and strength between the network layers. Although viral spreading may be unachievable in a single layer, for example a social network like Facebook, the critical threshold may be exceeded by joining different platforms. Within a given platform, people alike can be clustered using community detection algorithms. Once the communities are identified, influence maximization algorithms have been established to select these persons that maximize the spread of viral content. Although this discrete optimization problem is computationally difficult—or NP-hard—mathematicians have proposed algorithms that can efficiently predict who to target to give a campaign the best chance of going viral. On top of that, optimal pricing strategies have been developed to reward recommenders.

The FotoQuest Austria app aims to engage citizen scientists in their campaign - network theory may help them go "viral." © IIASA

The FotoQuest Austria app aims to engage citizen scientists in their campaign – network theory may help them go “viral.” © IIASA

Although the literature is extensive, the nature of the results is often theoretical and involves mathematically complex models and algorithms. Considering that only partial information on the network is usually available, it is not straightforward to bring this knowledge back to a practical marketing campaign. So researchers in this field are trying to bridge the gap between theoretical results and practical problems. The generic, powerful methods of network science are sufficiently versatile to capture the specifics of real-world applications. As such, network science can provide guidelines that can bring great value for the design of heuristic methods in marketing strategies.

Note: This article gives the views of the author, and not the position of the Nexus blog, nor of the International Institute for Applied Systems Analysis.

What do our models really represent?

By Dan Jessie, IIASA Research Scholar, Advanced Systems Analysis Program

As policymakers turn to the scientific community to inform their decisions on topics such as climate change, public health, and energy policy, scientists and mathematicians face the challenge of providing reliable information regarding trade-offs and outcomes for various courses of action. To generate this information, scientists use a variety of complex models and methods. However, how can we know whether the output of these models is valid?

This question was the focus of a recent conference I attended, arranged by IIASA Council Chair Donald G. Saari and the Institute for Mathematical Behavioral Sciences at the University of California, Irvine. The conference featured a number of talks by leading mathematicians and scientists who research complex systems, including Carl Simon, the founding Director of the University of Michigan’s Center for the Study of Complex Systems, and Simon Levin, Director of the Center for BioComplexity at Princeton University. All talks focused on answering the question, “Validation. What is it?”

To get a feel for how difficult this topic is, consider that during the lunch discussions,  each speaker professed to know less than everybody else! In spite of this self-claimed ignorance, each talk presented challenging new ideas regarding both specifics of how validation can be carried out for a given model, as well as formulations of general guidelines for what is necessary for validation.

How closely does a model need to mirror reality? © Mopic | Dreamstime.com - Binary Background Photo

How closely does a model need to mirror reality? © Mopic | Dreamstime.com – Binary Background Photo

For example, one talk discussed the necessity of understanding the connecting information between the pieces of a system. While it may seem obvious that, to understand a system built from many different components, one needs to understand both the pieces and how the pieces fit together, this talk contained a surprising twist: oftentimes, the methodology we use to model a problem unknowingly ignores this connecting information. By using examples from a variety of fields, such as social choice, nanotechnology, and astrophysics, the speaker showed how many current research problems can be understood in this light. This talk presented a big challenge to the research community to develop the appropriate tools for building valid models of complex systems.

Overall, the atmosphere of the conference was one of debate, and it seemed that no two speakers agreed completely on what validation required, or even meant. Some recurring questions in the arguments were how closely does a model need to mirror reality, and how do we assess predictions given that every model fails in some predictions? What role do funding agencies and peer review play in validation? The arguments generated by the talks weren’t limited to the conference schedule, either, and carried into the dinners and beyond.

I left the conference with a sense of excitement at seeing so many new ideas that challenge the current methods and models. This is still a new and growing topic, but one where advances will have wide-ranging impacts in terms of how we approach and answer scientific questions.

IIASA Council Chair Don Saari: Validation: What is it?

Note: This article gives the views of the author, and not the position of the Nexus blog, nor of the International Institute for Applied Systems Analysis.