Great Inventions that Changed the World (Wei/Inventions that Changed the World) || Security

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    Mankind faces many threats to their lives, as well as to their health, freedom,

    family, employment, income, possessions, and standard of living. In Paleolithic

    times, the big threats came from hostile animals and locusts, wind and rain-

    storms, oods and droughts, and volcanic eruptions and earthquakes. In modern

    times, one of the new and more important threats is to economic well-being, from

    loss of income and savings. But the most dangerous of all is human violence,

    from robbers and gangs, and invading troops. Such threats can easily overwhelm

    the defensive resources of individuals and communities, and require the collective

    organizations of many people to establish a police force and army. Many kings

    and rulers have styled themselves as defenders and protectors of the people, and

    have used this protection from misfortunes to give them the legitimacy to require

    services and taxation.

    The forces of nature are generally too strong for our efforts to prevent. We are

    dimly aware that government scal and monetary policies may inuence business

    cycles, but we cannot predict nancial meltdowns ahead of time. Most of our inven-

    tions and methods of dealing with threats to security are defensive in nature, such as

    predicting and giving advanced warnings, building dams and dikes against oods,

    and investing in private insurance and public welfare against economic threats.

    Human violence often occurs when the victims give an impression of weakness and

    vulnerability. The best deterrent seems to be a good shield against attacks and the

    ability to retaliate and cause severe damage to the attackers, which makes the act of

    aggression less protable.


    Human history is full of stories about the wrath of nature that has given mankind

    overwhelming hazards and disasters. Many of these disasters are geological, such

    as earthquakes, volcanoes, and landslides; some are hydrological, such as the ood-

    ing of rivers and lakes and tsunamis from the oceans; some are biological, such as

    plagues of locusts and epidemics; and some are climatic events, such as hurricanes

    and storms, as well as droughts and heat waves. For defense against erce animals

    in the Epic of Gilgamesh, the heroes had axes, knives, quivers, and bows to battle

    Humbaba and the Bull of Heaven. Against threats from geology and hydrology,

    our ancestors had little defense except to heed early warnings and ee to safety.

    Great Inventions that Changed the World, First Edition. James Wei. 2012 John Wiley & Sons, Inc. Published 2012 by John Wiley & Sons, Inc.


  • Utnapishtim and Noah both had early warning from the gods that a great ood was

    coming, which gave them time to build their boats, load them with supplies, and

    oat to safety. The last century alone brought many devastating natural disasters: in

    1953, the Zuider Zee in Holland had an unprecedented storm; in 2004, the Banda

    Aceh earthquake created a tsunami in the Indian Ocean; and in 2005, the Hurricane

    Katrina slammed into New Orleans.

    Despite our progress in anticipating these threats of nature and organizing

    recovery efforts, we have very few triumphant solutions and need more effective

    inventions. For the threat of earthquakes, for example, we have the following


    Identication of Natural Risks and Human Vulnerabilities: Such as keepinghistoric records of the California earthquakes on San Andreas Fault and notic-

    ing the types of damage to collapsed buildings, highways, and bridges.

    Preparations: Reducing vulnerabilities such as the design of earthquake-resistant structures in earthquake zones and the construction of evacuation

    facilities and shelters.

    Forecasts: Prediction methods based on past records and leading indicators,such as earth tremors and animal behaviors.

    Crisis Management: Execution of evacuation, search and rescue, and shelter.

    We may understand the origin of earthquakes in the movement of tectonic

    plates, but we can neither predict the time nor the place of the next big quake, such

    as the Haiti earthquake of 2010 and the Tohoku earthquake of 2011, nor can we stop

    or lessen the power of destruction.

    We can also identify major areas vulnerable to ooding, such as the lowlands

    near river valleys that are fed from mountain snowmelt in the spring and the low-

    lying seacoasts such as Venice, Amsterdam, New Orleans, and Bangladesh. We

    have weather models to predict the coming of storms and we have radar and earth

    satellites to check the formation and status of hurricanes. Nevertheless, we under-

    estimated the severity of Hurricane Katrina in 2005 that ooded New Orleans. We

    have invented and built dikes and dams that are partially successful. Nature contin-

    ues to give us punishing blows, and societies usually do not invest enough resources

    in such preventive measures, as we cannot predict with accuracy when and where

    disaster could strike and how severe the strike could be. There is also a human tend-

    ency to spend money on immediate enjoyments that are certain and neglect distant

    calamities that may never happen. The construction of dams and levees also creates

    displacement, such as moving the residents in low valleys and installing obstacles to

    the spawning of returning salmon from the sea. Outrage over human or environmen-

    tal displacement can generate strong political opposition.

    5.1.1 Dikes and Dams

    A dike is an embankment or raised platform parallel to the shores of a sea or to the

    banks of a river to prevent ooding; a levee is a natural or articial embankment

    next to a river. A dike is built to protect the houses and farms along the river from


  • ooding. They are usually built with compacted earth and are seldom taller than

    15m, but can be hundreds of miles long. A dam is a perpendicular barrier across a

    river to control the water ow, to create a lake or reservoir upstream for irrigation,

    and to generate electricity. Dams are built with stronger material such as steel-

    reinforced concrete to hold back the water. They are sometimes as high as 300m,

    but they are no wider than a river. A photograph of a tall and narrow dam can be

    much more dramatic than that of a low and long dike.

    The rst levees were constructed over 3000 years ago in ancient Egypt, where

    a system was built along the west bank of the River Nile for more than 1000 km,

    stretching from modern Aswan to the Nile Delta on the shores of the Mediterra-

    nean. The Mesopotamian civilizations also built large levee systems. Because a

    levee is only as strong as its weakest point, the heights and standards of con-

    struction have to be consistent along its length. Some historians have proposed

    that such large-scale hydraulic efforts would have required a strong governing

    authority to compel each person in the area to contribute time and effort and

    may have been the most important reason for the development of governments

    in early civilizations. In modern times, prominent levee systems exist along the

    Mississippi River in the United States, as well as the Po, Rhine, Meuse, Loire,

    Vistula, and Danube in Europe.

    The Yellow River was a source of great sorrow in Chinese history, as it

    often ooded and destroyed many homes, farms, and lives. Emperor Shun needed

    a minister to tame the river, so he appointed Kun for the job, who tried to control

    the ood with barriers. After 9 years with no success, Shun executed Kun but

    appointed Kuns son Yu to continue the job of taming the waters. Yu inspected

    the rivers to discover the failure of Kun, and decided to change the control

    method from barriers to diversion of water. He traveled extensively to establish

    the elevation of the land and dug canals to divert the water to the sea. He did not

    rest and took time out even when he was newly married. He even passed his home

    three times in subsequent travels, but did not go in to visit his family. For 13

    years, he traveled for his work, wore the coarsest clothes, ate the poorest food,

    and slept in the lowest hovels. After 13 years, all the rivers owed smoothly to

    the sea, proving that he had solved the ooding problem for a while. When

    Emperor Shun completed 33 years on the throne, he gave the throne to Yu, who

    became the founder of the Xia Dynasty in the year 2070 BCE, which lasted for

    over 400 years. Becoming emperor is probably the highest award ever received

    by any inventor or engineer in history.

    Consider a river with a V-shaped channel, which ows at a normal height

    and width under normal ow conditions. When the ow is increased by a factor

    of 4, the height and width of the river will double. This doubling leads to inunda-

    tion of the adjacent land, which are highly valuable due to the fertility of the soil

    and the convenience in transportation. Levees are usually built by piling earth on

    a cleared, level surface. They are broad at the base and taper to a at and level

    top, where temporary embankments or sandbags can be placed. The levee surfaces

    must be protected from erosion, so they are planted with vegetation such as

    Bermuda grass in order to bind the earth together. On the landside of high levees,

    a low terrace of earth is usually added as another antierosion measure. On the


  • riverside, erosion from strong waves or currents presents an even greater threat to

    the integrity of the levee. The effects of erosion are countered by planting with

    willows, weighted matting, or concrete revetments. Levees turn the river into a

    U-shaped channel and prevent the river from becoming wider, which protects the

    valuable land near the river; but the constant deposition of silt causes the river

    level to become higher and increases the ow velocity. After many years of silt

    deposits at the bottom of the channel, the levees have to be raised higher than

    before; eventually, the river and its levees can become higher than the surrounding

    land, such that a break would cause much greater damage. Sometimes a levee is

    deliberately breached to ood over less inhabited farmlands in order to save the

    levees in crowded cities.

    The Mississippi River levee system for the main river and principal tribu-

    taries represents one of the largest systems found anywhere in the world. It com-

    prises over 5800 km of levees extending some 1600 km along the Mississippi,

    stretching from Cape Girardeau, Missouri, to the Mississippi Delta. In the eigh-

    teenth century, the levee system was started by French settlers in Louisiana to

    protect the city of New Orleans. The rst Louisiana levees were about 1m high

    and covered a distance of about 80 km along the riverside. After many decades

    of connement behind levees, the deposition of silt raised the bottom of the river

    that then required the building of higher levees, so that the river eventually

    became higher than the surrounding land. By the mid-1980s, the Mississippi

    levees had reached their present extent and averaged 8m in height, while some

    levees are as high as 15m.

    Before we design a dike to keep out high water, we must ask how high a dike

    is needed to stop any foreseeable disaster. The best design depends not only on the

    available material and structure and on the reliable forecasts of likely hurricanes but

    also on what we can afford and are willing to spend. The design of a dike or levee is

    geared to the highest historic level of water, but the future expected level in the river

    or lake cannot be predicted with precision. A future storm can be greater than any in

    previous recorded history. Since record-keeping began in 1920, the greatest Cate-

    gory 5 Atlantic hurricanes have been Camille in 1969 and Allen in 1980, both with

    a top wind of 190 miles/h (317 kph). Consider the following list of Atlantic hurri-

    canes that reached Category 5:

    Decade Number Max speed (mph) Max speed (kph)

    1920 1 160 267

    1930 3 160 267

    1940 1 160 267

    1950 4 185 308

    1960 6 190 317

    1970 3 175 292

    1980 3 190 317

    1990 2 180 300

    2000 8 185 308


  • Should we design the dikes in New Orleans to keep out 200mph hurricanes,

    or even higher, for greater safety? What if the appropriated funds were only suf-

    cient for 180mph? Who would be blamed if the next hurricane turned out to have

    top winds of 220mph? In the next 50 or 100 years, what is the likely maximum

    ood level, and how much safety margin should we build into the design? What

    does likely mean, and what about Black Swan events that happen less than

    once a century? The Tohoku earthquake of Japan in 2011 was a magnitude 9.0,

    which is higher than any previously recorded Japanese earthquake. The penalty

    for building a dike wall too low is ooding and the loss of properties and lives;

    the penalty for building the wall too high is wasting resources that may be better

    spent for other urgent matters, such as food and medicine for the poor. Reliable

    forecast methods are comparable in importance with the best material and struc-

    ture for the dikes.


    A person in modern society needs a steady stream of cash for daily necessities, as

    well as for major expenditures from time to timesuch as buying a house or car,

    providing for severe illness, paying college expenses, or starting and expanding a

    business. The steady stream and major expenditures can come from a source of

    income from employment, withdrawing from savings, or borrowing from others. In

    the Paleolithic world, people foraged every day and stored what they could spare for

    winters and for the years of drought and famine. In the modern money economy,

    income is generated mostly by employment and the surplus of income not spent can

    be saved and invested in assets such as bank deposits and properties. Tangible assets

    include land, houses, cars, furniture, and other durable goods; nancial assets

    include bank accounts, stocks and bonds, pension plans, and equity in small


    Income is threatened when an individual is unable to work because of illness,

    accident, or old age; the individual can also be laid off by the employer due to

    downsizing, outsourcing, business failure, and general economic recession. A tem-

    porary loss of income can be offset by withdrawing from personal savings and from

    unemployment insurance and social security. The inventions of banking, insurance,

    and pension plans provide networks for partial protection, by sharing risks against

    unpredictable events. A severe international recession and depression may over-

    whelm the local networks, and the national government or international organiza-

    tions, such as the World Bank and the International Monetary Fund are called upon

    to protect those affected.

    An individual asset such as a house or shares of stock can lose value due to

    external economic conditions or internal problems; an investor can reduce the risks

    by a diversied portfolio with different assets that are not correlated. For instance,

    when the interest rate on xed bonds goes up, there is often a drop in the stock

    market, as many investors may choose to sell their stocks to buy the higher yield

    bonds. So if the investor has both stocks and bonds in h...


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