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EXYSTENCE NoE Prof. John Casti, Institute for Monetary Economics, Vienna, Austria and Complexica Inc. Santa Fe, NM, USA. The World of Business in a Box Today I think that we have heard
a lot of about individual companies. Eve talked about Rolls Royce Marine, Hannu
talked about UPM and there was some fairly general discussion involving
sociology, philosophy, psychology and some things in between about motivation
and understanding about how a business enterprise actually works. The topic that
I'm presenting today is not of that kind, though it is perhaps something which
focuses on trying to understand business as a science. One of the crucial
aspects of any kind of actual science is the ability to do controlled
containable experiments and hence to test hypotheses. (a) A medium size number of agents making up the system. In the football game it's the players, but it could be traders in a financial market or animals in an evolutionary ecosystem or firms in an industry. It means it's not such a small number that you could work out all the interactions with a back of an envelope calculation and it's not such a big number that you can statistically aggregate it into quantities that tell you anything you really want to know about the system. So what is a medium number? Well it's certainly bigger than two. Think about the 'n body gravitational problem' in physics. We know that when 'n' is only two bodies, say two planets moving in each others gravitational field, then there's some formula that, given the position and velocity you can work out where each will be at some future time. However, as soon as you have three or four bodies then, though in principle you could work it out there's no formula. If we think about classical physics at the other end of the scale; say a litre bottle full of gas with about 1023 molecules moving around then, whilst in principle you could work out the future state, in practice you cannot. Of course we would never try to do that anyway because, since Boltzmann, we know that you can statistically aggregate the molecules to higher level quantities called pressure and temperature because the objects are all homogeneous. We also have a relationship which links them called the ideal gas law: PV = nRT. So 'a medium sized number' is more than two and certainly less than 1023. Thus the definition will take into account many systems that we encounter in everyday life in which the number of agents will be a few dozen to a few hundred thousand. (b) The second property is being 'intelligent and adaptive'. 'Intelligent' here is meant in a very low level sense as 'objects that make up the system interacting according to rules'. At any given moment they 'decide' what action to take. So if in a traffic system you're a driver then you can decide whether to speed up or slow down. In a real system you're continually monitoring your rules to see whether it's producing results that you're satisfied with. If, for example, you're a currency trader at Citibank and you have a rule on whether to buy or sell or hold, then if you're making money you stay with the rule. If the rule stops working then you change to a different rule or invent a new rule. So, in investigating a system you're always exploring the possible space of rules that agents might be following and that's what is meant by 'intelligent'. The system is adaptive because the agents change to a new rule if they don't like the one they've got. And that's exactly the kind of thing that doesn't happen in the natural sciences. The rules that govern planets and electrons are not changing ones. So you could say that physics is a special case of biology though a lot of physicists like to think it's the other way round. I personally think it's much simpler than biology by several orders of magnitude. (c) The last characterization is 'local information' which just means that there's no object which knows what everyone else is doing. On the football field for example, a player knows what some of the other players are doing but doesn't know what all of them are doing. And a driver on the motorway will know what drivers in the vicinity are doing but not what others farther away are doing. Sometimes that matters and sometimes it doesn't. Let me now talk about how to use the computer as a laboratory in order to understand problems in the business world. The motivation or reason for building electronic copies of real world systems is to understand the possible consequences of different options. Here is a list of requirements for constructing effective agent-based models; one that is useful in setting up a real business. It is no use creating a world that nobody understands so here are a lot of conditions that have nothing to do with actual techniques but are practical considerations; the rules if you like, that you have to follow if you want customers. Customers want to see things that are easy to use and don't take for ever. Here is the list: · The simulation must capture
the user's consumer, competitive, economic and regulatory environment. For the rest of this talk I want
to give you a real world example of how the method is used and this has to do
with a problem in the world catastrophe insurance industry. A few years ago I
attended a meeting in Bermuda which was convened by a lot of the world
catastrophe insurers and re-insurers who are the people who insure the insurers.
The kind of cover under consideration is for earthquakes, hurricanes, floods,
storms and so on, and these people wanted to know how the science of today could
help their industry. At the meeting there were four speakers, myself and three
climatologists, and the insurers thought that the single most important thing
that science could offer them was a better method for predicting hurricanes. I
thought this was interesting because if you had a perfect 100% method for
predicting hurricanes it would be the worst thing for the insurance industry
because you would be out of business. The very essence of insurance is
uncertainty, not certainty and that's what you have to consider. If you know
nothing however, you have no way of judging the likelihood of a hurricane of
certain magnitude striking some place and that's also bad because you don't have
any way of knowing what to charge your customers. So logically there is some
optimal level of uncertainty for a healthy business, between total knowledge and
complete ignorance. Nobody knows that level, but I suggested that with the
technology that was then available, we should be able to construct a copy of the
situation inside a computer of the interaction of the customers who buy
insurance, the primary insurers who issue the policies and the re-insurers who
buy some of the risk. · How do the frequency,
magnitude, and geographical distribution of natural catastrophes affect the
profitability of insurers and re-insurers? Every one of the simulations had
to have feedback from people in the industry saying what actually happens in
their world. The time scale that we used in a particular run was forty
time-steps of three months giving a ten year period. This was a long enough
period of time for things like inflation, interest and other things to change
which suited the demands of the insurers. Questions: What is the difference between agent-based modelling and the kind you are talking about and how much mathematics is there in the simulations? John: Well, I tend to think that agent-based modelling is a particular style of simulation because you have the individual objects that make up the system and you have to specify rules of interaction which depend on what the other agents are doing at the time. These rules are expressed mathematically. But in general simulations come in lots of sizes and shapes and colours and some are very mathematical like the ones you do in physics. In Stephan Wolffram's book the simulations are a lot more mathematical than the insurance model which is somewhere in between. There was an agent-based model of the stock market done in Santa Fe which had no mathematics in it. There were just kind of trading rules and not much mathematics of any kind so I think it very much depends on the situation. I don't think it matters very much whether you call it a simulation or an agent-based model. It's just a question of whether it answers the questions you're interested in. Questioner 2; what is the cost of the simulation you describe? John: Two hundred thousand dollars in 1996. We did it over a period of one year, but if a commercial company did it now, it might cost two hundred and fifty thousand dollars and you would get it in three months. Questioner 3: I would like to say something about agent-based models. I am doing research using neural networks, fuzzy logic and evolutionary algorithms or co-evolution simulation. On a daily basis I am faced with the problem of approximation of function because if you have to do modelling of human behaviour it's very complex. My lab was involved in one project which was supported by the E.U. called U.N.I.T.E. which was promoting intelligent technologies and was focused on simulating the clients of a commercial bank. We had a very good relationship with the bank and said we needed to categorise the type of client. The coordinator from the bank set up twenty five or twenty six kinds of client profile because they wanted to create a system which would be able to warn the bank which clients would move or leave the bank. Modelling the behaviour of such a client was not easy but we ended up with a 70 or 80% accuracy of characterisation. But communication with the client is difficult because you are not selling a plug and play system so it is crucial that the company is able and willing to cooperate. So I have two questions: (a) how well does the system you are selling adapt to human behaviour? and (b) how do you measure the quality of it? John: The modelling of human
behaviour depends upon how much of the human behaviour you have to model and
that in turn depends on the questions the model is designed to address. So if
you're creating a road traffic network you have to understand the psychology of
different types of drivers and the demographics; where they live and where they
shop, where they work, where their children go to school and so on. But it's not
important to know things like the colour of their hair or height. I did an
exercise two years ago for a supermarket chain and they wanted to understand the
dynamics of the shoppers. They had a lot of data on the demographics, whether
young or old for example and they had different kinds of shopping lists. So for
that exercise the only thing that really mattered was the kind of shopping list;
what was it that they intended to buy when they came to that market place. We
had to work out how they moved through the store and where the best place was to
put things. Questioner 3: I mean when the model needs new data input. John: So you mean when new
information is available how does it reconfigure? It depends on the model.
Reconfiguration for the insurance model was fed in once a year when the
simulation was stopped and the users looked to see how it was doing in mirroring
what was happening in the real word. The model didn't do it automatically. Questioner 4: When you talk about 'would-be-worlds' how do I find which set of rules lead to the best possible answer? There are some ways of modelling that can produce something like rules but only applied to a particular case and general rules would probably misfire in a number of cases. John: Well, that's a good
question and in all the exercises that I have participated in you go to the
client. For the insurance project we went to the insurers and said: 'under these
circumstances what do you do and why do you do it? It's finding a rule of
action. The road traffic data is filled with experiments that people have done
on drivers, finding out what they do under different circumstances. There's no
substitute for that. Questioner 4: As an anthropologist I ask people for their rules and then I see them do something else. John: That's OK. If you see them do something different then you have to adjust to what you see. Questioner 4: Well there are sometimes rules that produce rules and you need to be close to see how that works. John: Well I can only state what I said at the beginning, and that is that this is not a universal methodology. If you can't produce meaningful rules than you need to do something else. Eve: I think part of the problem is that such rules don't the status of unchanging laws and we constantly have to ask whether they are principles guiding the action. John: Yes perhaps it's better to call them policies. You have to know who your agents are before you can give them rules. If you're engaged in some modelling exercise like a football game and you say these are the questions that I want to address then you know who the agents are and how they will operate under the rules of the game. The context matters and as soon as you specify the context then it becomes easier to say who the agents are and what constraints they have. They're the objects that interact to produce the properties you want to know about. There's no point in considering agents that are outside the context you're interested in. Questioner 5: I'm doing a thesis on leadership and my main question is: 'How do you run a successful company and how would you characterise that in terms of agent-based modelling?' Eve: Someone offered earlier to link this to self organisation and motivation. Would you like to go ahead? Commentator A on leadership: Well I just want to add a few comments to this question of self organisation and motivation. I have had a long experience in business and in trying to reflect on my experiences I came up with one rule which is the key to long term success, not only in business but in life and that is the moral capital. I think that translates as the amount of honesty and the amount of corruption there is in an organisation and in a country. It is something that can be explained by game theory, because in any organisation you want to create value which means you have to play a 'plus sum' or win/win game with all the participants. Game theory tells us quite clearly that in contrast to 'zero sum' games where withholding information and betrayal are the winning strategies, 'plus sum' games depend for success on honesty, integrity and transparency. It becomes the most important success factor in the development of an organisation. We may be able to buy an abundance of capital, knowledge and expertise but moral capital has to be created in situ. Moreover, in selecting a leader, to me integrity is a top priority. Commentator B on self-organising technology: If you go to the paradigm of complex systems the technology is more or less pre-coded, which means you have to define everything at the start of building the system. You have to consider all the possible things that might come up with the user in order to design a system that doesn't fall down in use, which is pretty impossible. That's really the present paradigm, but in the coming years we will shift to another paradigm which is to use some kind of self-organising technology which means that we are no longer tied to this kind of recoded knowledge. The systems will be truly adaptive in that they will learn as they go along. Take the example of cellular networks which is my area of expertise. Cellular radio networks are full of hundreds of parameters that the radio engineer has to tune up during use to make the system work in the best possible way. It's a very tedious and skilled task and after every major change to the network you have to do it again. I think we may be able to get out of that in the future by the system itself taking care of optimisation, so maybe we shouldn't use the term 'parameters' at all. Eve: Could I hear people's view on that? Commentator C: From my point of view it's artificial intelligence that you're talking about. If you've seen the film Artificial Intelligence it's the creation of a system which learns by gathering and using information, but it's the question of whether to use several agents. If you can decompose your task into a number of sub-tasks which can be easily carried out by smaller entities as agents and you allow them to interact then you can progress the technology that way. Commentator B: I think we are talking about the same thing. I am not talking about artificial humans, but that kind of decomposed task. Commentator C: But what is the difference between artificial human and this kind of technology? Commentator B: Well artificial human is one part of it, but I'm also talking about decentralised learning systems. Eve: Distributive? Commentator B: Exactly, so we're talking about the same thing. Commentator C: Well, Sony is doing this IBO stuff (robot learning dog). The next generation of IBO seems to be that they will launch IBO to hundreds of thousands of families in an interacting reinforcement environment. Each IBO will adapt and gather information which is then sent back to the 'mother' computer where the knowledge is fused and sent back again so there's a radically incremental increase in learning about the world. Eve: And I think there's an important question concerning what the two of you have been talking about, which is the question of how we learn in a distributive way. We have to ask whether it's in terms of intelligence or knowledge or maybe leadership. Maybe that's the future. |