Tuesday, July 7, 2015

ENVS 400 Independent Study - Daniel Woods - Answers to in-class questions for Ch 1, 2, & 3.

Chapter 1 Questions and Responses
1.     1.   How is a system defined?

“A system is an interconnected set of elements that is coherently organized in a way that achieves something.” An example of a system is a library; it is a coherently organized building full of books that achieves the accessibility of the information in the books better than if the books were disorganized, as well as preserves that information by preserving the books.
        2. Explain the difference between elements and interconnections in systems.  Which are more important? 

Elements are the individual parts of a system. They are usually physical, but can be intangible, like social norms. Interconnections are the relationships that hold elements together. In the library, the elements are the books. The interconnections are the common subjects of the books, which is the starting point for organizing them to make them easy to find.
     3. Define stocks and flows; make a stock-and-flow diagram of our system.

Stocks are the resources in a system that can be added to or depleted, and can be tangible or intangible. Flows are the avenues of change to the level of stocks. The stock of a library is all of the media contained in it, and the flow is the rate at which the media is checked out, lost, damaged, and returned.

Flow: Books Checked In à Stock: Books à Flow: Books Checked Out à Flow: Book Reading 
Speed à Flow: Books Checked In

4.       4. Why are there lags in system behaviors?

There are lags in system behaviors because stocks have inherent momentum. For example, the stock of books in a library would respond slowly to more interest in reading because there are so many books in the library. Flows are limited to a certain speed as well; a person can only check out a few books at a time, and reading them is going to take a long time.
      5. Define: stabilizing feedback, reinforcing feedback.

Stabilizing feedback regulates the system to keep it from changing. Reinforcing feedback causes the system’s stock to grow or diminish. Stabilizing feedback in the library is the fines for not returning a book that guarantee that there will be money to buy the book again if it is lost. Reinforcing feedback is the culmination of knowledge and ongoing research that is enabled by a library that guarantees that there will be more books available that a library might be obligated to have. The stock of books is always increasing, never decreasing.

Chapter 2 Questions and Responses
     1. Describe the differences between complicated and complex systems.

According to the TED talk that is linked to in the power-point, a complex system has many individual, similar parts that all interact with each other to create a system. The individual parts are governed by simple rules that, when the individuals come into contact with each other, create a system, which has an outcome that could not be predicted by knowing the rules that govern the individuals. In other words, “the whole is the sum of its parts”. In contrast, a complicated system is one with many parts that are different from one another, and they all do a separate job that contributes to the goal of the system. Their behavior  as a group is therefore not as puzzling, because they all do their activity with the intention of the result that happens.

2.       2.  Using the system diagrams we made last week as examples, diagram key components of the system you have chosen to work with this semester (stocks, flows, information links/feedbacks.

         Recycling Stock/Flow Diagram:

Chapter 3 Questions and Responses

1. In the context of systems, what is resilience? Give examples.  How can resilience of a system be measured?

"Resilience is a measure of a system's ability to survive and persist within a variable environment."- p 75. "Resilience arises from a rich structure of many feedback loops that can work in different ways to restore a system even after a large perturbation." - p76. I think a good example of resilience is the human liver, which can regenerate itself from only 1/4 of it's original mass. The ability for a country to rebuild itself after losing a war, such as Japan's loss in WWII and subsequent rise as a technological powerhouse , is another example. The time it takes for a system to return to the state it was in before the disturbance is a good way to measure resilience. Another way to measure resilience would be to see how much more prepared the system is next time the disturbance occurs.

2. What is self-organization?  Give examples?  Is this an inherent property of complex systems?

Self-organization is the ability of a system's elements to work toward a common goal without having to rely on a central authority. Instead, each individual communicates with the individuals around it, and the cumulative effect of all the communication is achieving the goal. This is how ants work, as described in the National Geographic reading; each ant interaction involves an exchange of chemicals that give the receiving ant information about the other, and the ants draw conclusions about what to do next based on the frequency of these interactions. Birds and other groups of moving animals use self-organizing rules to move in the same general direction without blocking each other. This is how complex systems come to be; they are the cumulative effect of many individuals following the same simple rules.

3.  Describe complexity and hierarchies, how are the two terms related?  Again, give examples.

Hierarchies are sub-systems of systems that organize and divide a large system. Each sub-system is more tightly connected with itself than with the other sub-systems, which works to divide tasks, so that a system can solve several different problems simultaneously and with efficiency. If complexity is the sum of a system's parts, then it is also the sum of the sub-systems. Sub-systems can also have complexity, such as how each animal population is a sub-system of the whole ecosystem. Another example are all the sub-systems in a car; the air-conditioning, engine cooling, window motors, and other systems work to get you down the road safely. And you in your car are but a sub-system of the larger system of commuters and consumers, who are all contributing to moving capital and ideas around. 

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