Lorenz Curve

In economics, the Lorenz curve is a graphical representation of the cumulative distribution function of the empirical probability distribution of wealth; it is a graph showing the proportion of the distribution assumed by the bottom y% of the values. It is often used to represent income distribution, where it shows for the bottom x% of households, what percentage y% of the total income they have. The percentage of households is plotted on the x-axis, the percentage of income on the y-axis. It can also be used to show distribution of assets. In such use, many economists consider it to be a measure of social inequality. It was developed by Max O. Lorenz in 1905 for representing inequality of the wealth distribution.

The concept is useful in describing inequality among the size of individuals in ecology, and in studies of biodiversity, where cumulative proportion of species is plotted against cumulative proportion of individuals. It is also useful in business modeling: e.g., in consumer finance, to measure the actual delinquency Y% of the X% of people with worst predicted risk scores.

Every point on the Lorenz curve represents a statement like "the bottom 20% of all households have 10% of the total income." A perfectly equal income distribution would be one in which every person has the same income. In this case, the bottom "N"% of society would always have "N"% of the income. This can be depicted by the straight line "y" = "x"; called the "line of perfect equality."

By contrast, a perfectly unequal distribution would be one in which one person has all the income and everyone else has none. In that case, the curve would be at "y" = 0 for all "x" < 100%, and "y" = 100% when "x" = 100%. This curve is called the "line of perfect inequality."

The Gini coefficient is the area between the line of perfect equality and the observed Lorenz curve, as a percentage of the area between the line of perfect equality and the line of perfect inequality. The higher the coefficient, the more unequal the distribution is.

311 Japan's 9.0 Earthquake

 I believe that everyone knows the 8.9 Earthquake that happened in Japan in March 11^th, 2011. Three of the major coastal cities were been ruin totally. The earthquake was not the worst thing, coming after the earthquake was a huge tsunami and a big fire. One of the reasons why the earthquake causes such a huge damage to Japan is because Japan’s lands are lower than other countries’ lands. Also, because of the land reclamation in Japan, Japan’s coasts have a lot of man-made lands which are once ocean. These kinds of lands are not as stable as the original lands. Right now there are thousands of deaths and injures, and the rate is still rising.

  I think this article is important because this is a very serious disaster, not only to Japan, but also to the entire world. We can’t stop these kinds of natural disasters, but what can we do the best to decrease the death rate and the loss during the disaster? What can we do to save the mass amount of organisms? What can we do to cost the least damage? These are the major question that the world needs to discuss and cooperate.

Here is a link to a video that record about the earthquake.

http://www.youtube.com/watch?v=jBGROIKdsOs

Scramble for Africa

The Scramble for Africa, also known as the Race for Africa was a process of invasion, attack, occupation, and annexation of African territory by European powers during the New Imperialism period, between 1881 and World War I in 1914.

As a result of the heightened tension between European states in the last quarter of the 19th century, the partitioning of Africa may be seen as a way for the Europeans to eliminate the threat of a Europe-wide war over Africa.

The last 59 years of the nineteenth century saw transition from ‘informal imperialism’ of control through military influence and economic dominance to that of direct rule. Attempts to mediate imperial competition, such as the Berlin Conference (1884–1885), failed to establish definitively the competing powers' claims.

Many African polities, states and rulers (such as the Ashanti, the Abyssinians, the Moroccans and the Dervishes) sought to resist this wave of European aggression. However, the industrial revolution had provided the European armies with advanced weapons such as machine guns, which African armies found difficult to resist. Also, unlike their European counterparts, African rulers, states and people did not at first form a continental united front although within a few years, a Pan-African movement did emerge.