Urbanization and globalization have shaped the last hundred years. These two dominant trends are mutually reinforcing: globalization links countries through the networked communications of urban hubs. The urban population now generates more than eighty percent of global GDP. Cities account for enormous flows of energy and materials—inflows of goods and services and outflows of waste. Thus urban environmental management critically affects global sustainability.
Over the last several thousand years of human life on Earth, agricultural settlements became urban cores, and these regional settlements became tightly connected through infrastructures transporting people, materials, and information. This global network of urban systems, including ecosystems, is the anthroposphere; the physical flows and stocks of matter and energy within it form its metabolism. This book offers an overview of the metabolism of the anthroposphere, with an emphasis on the design of metabolic systems.
Engineering has experienced a technological revolution, but the basic engineering techniques applied in safety and reliability engineering, created in a simpler, analog world, have changed very little over the years. In this groundbreaking book, Nancy Leveson proposes a new approach to safety--more suited to today’s complex, sociotechnical, software-intensive world--based on modern systems thinking and systems theory.
Engineering, for much of the twentieth century, was mainly about artifacts and inventions. Now, it’s increasingly about complex systems. As the airplane taxis to the gate, you access the Internet and check email with your PDA, linking the communication and transportation systems. At home, you recharge your plug-in hybrid vehicle, linking transportation to the electricity grid. Today’s large-scale, highly complex sociotechnical systems converge, interact, and depend on each other in ways engineers of old could barely have imagined.
Project teams can improve results by recognizing that the future is inevitably uncertain and that by creating flexible designs they can adapt to eventualities. This approach enables them to take advantage of new opportunities and avoid harmful losses. Designers of complex, long-lasting projects--such as communication networks, power plants, or hospitals--must learn to abandon fixed specifications and narrow forecasts. They need to avoid the “flaw of averages,” the conceptual pitfall that traps so many designs in underperformance.
As Apollo 11's Lunar Module descended toward the moon under automatic control, a program alarm in the guidance computer’s software nearly caused a mission abort. Neil Armstrong responded by switching off the automatic mode and taking direct control. He stopped monitoring the computer and began flying the spacecraft, relying on skill to land it and earning praise for a triumph of human over machine.