Augmented Lagrangian Method for A Mean Curvature Based Image ...

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Augmented Lagrangian Method for A Mean Curvature Based Image Denoising Model Wei Zhu ∗, Xue-Cheng Tai †, and Tony Chan ‡ Abstract High order derivative information has been widely used in developing variational models in image processing to accomplish more advanced tasks. However, it is a nontrivial issue to construct efficient numerical algorithms to deal with the minimization of these variational models due to the associated high order Euler-Lagrange equations. In this paper, we propose an efficient numerical method for a mean curvature based image denoising model using the augmented Lagrangian method.

• image signals from noisy images with lots of applications
• lagrangian method
• explicit solutions
• mean curvature
• noisy image
• minimization
• image
• surface
• model

Sujets

• Exposé
• University of Bergen
• Nanyang Technological University
• Universiti Sains Malaysia
• University of Alabama
• Method
• Signals
• Minimisation
• Surface
• Curvature

Informations

• Publié par: chawyang
• Nombre de lectures: 39
• Langue: English

Extrait

Colonial Legacy and Economic Development in Latin America1



Rafael Dobado González
Complutense University








“Such is the interest aroused by the
misfortune of a vanquished people that it
often makes men unfair to the
descendants of the victorious people.”
Humboldt (1822:1991), pp. 54-55.




1. Introduction


2 Colonialism is back in fashion again. In recent years it has
become a popular subject of study for economists and economic
historians. From among the several known forms of colonialism, the
Spanish colonial period in America is probably the one which is
drawing more attention. That is so because, for a growing literature,
there is a causal relationship between Spanish colonialism or, if you
prefer it, its colonial legacy and the past and present problems of
economic development in Latin America. The clearest expression of
those problems opinion would be the difference between economic
development in North America and in the rest of the Continent. Two

1
Draft: please do not cite or circulate.
2 It would appear that nobody is much concerned about the fact that under the
heading of “colonialism” there are being designated realities that, strictly speaking,
are incommensurable: what has Roman colonialism in pre-imperial Baetica
(Andalusia) in common with Cecil Rhodes´ activities in Zimbabwe? Or the conquest
of Tenochtitlan by Cortés in 1521 with the establishment of British rule in the
Hindustani Peninsula in 1858? Not much, in fact. Furthermore, some similar
historic episodes, with an undoubted importance and similarity with the aforesaid,
such as the invasion of India by the Moguls or the conquests in Asia, Africa and
Europe by the Ottomans are not usually associated with the idea of colonialism.
Therefore, let us accept that the idea of colonialism is generally associated with
Occidental Europe between roughly 1500 and 1960.
1 sets of works, the one by Engermann and Sokoloff (1994, 2002 and
2005) and the other by Acemoglu, Johnson and Robinson (2001a and
2002), have proved to be especially decisive. In fact, they have, in
my opinion, shaped what I term the “new orthodoxy” regarding the
relations between institutions, colonialism and economic growth.

This “new orthodoxy” is succeeding in exerting a growing
intellectual influence. In his latest book, The Mystery of Economic
Growth, Helpman devotes a whole chapter to institutions and politics,
which includes a section dealing with the influence of colonial origins
3 on economic development. In The White Man’s Burden, Easterly also
adheres to those who postulate a connection between colonialism and
4contemporary economic problems. Of more practical importance is,
perhaps, the fact that the World Bank has adopted the “new
orthodoxy” in several of its latest publications. The examination by
De Ferranti et al. (2004) of the historical roots of inequality in Latin
America basically consists in a description of the main points of the
5“Engerman-Sokoloff version” of the “new orthodoxy”. The Report on
6World Development is a monograph on equity and development.
However, in reading it, one becomes surprisingly aware of the
presence of terms closely associated with the history of colonial Latin
America such as “conquistadores”, “encomienda”, “encomenderos”
and “mita”. The “new orthodoxy” is openly defended: “The
institutions that emerged in the main Spanish colonies greatly
benefited the Spanish crown and the Spanish settler elite, but they
7did not promote prosperity in Latin America.”

In Poverty Reduction and Growth: Virtuous and Vicious Circles
we again find, exposed explicitly, one of the basic tenets of the “new
orthodoxy”. Main contemporary economic problems in Latin America

3
“The influence of institutions imposed by colonizing powers on the development of
various territories and countries has received particular attention. Some have
argued that a colonizer has a decisive impact on the formation of its former
colony’s political, legal, and economic performance.” Helpman (2004, p. 122).
4 “This chapter argues that old conventional wisdom was correct –the previous
imperial era did not facilitate economic development. Instead, it created some of
the conditions for today’s unsuccessful interventions; failed states and dab
government.” Easterly (2006, p. 272).
5 “Following Engerman and Sokoloff (1997, 2000, 2002) and Acemoglu, Johnson,
and Robinson (2001, 2002), the authors of this chapter argue that the
contemporary situation cannot be understood without recognizing that extreme
inequality emerged soon after the Europeans began to colonize the Americas half a
millennium ago, and has been reflected in the institutions they put in place.” De
Ferranti et al. (2004, p. 41).
6
It is not by chance that the cover of the report – as a metaphor of inequality, in
my interpretation – shows a fragment of the mural by Diego Rivera entitled “Sueño
de una tarde dominical en la Alameda Central”, which is conserved in the Museo
Mural Diego Rivera, Mexico City.
7
World Bank (2005, p. 112).
2 (low income level, inequality and persistent poverty) are not
independent of the Spanish “colonial legacy”:

“Is there something intrinsic to the region that has left it with
relatively low growth and high levels of inequality and poverty?
The World Bank’s Latin American region flagship Inequality in
Latin America: Breaking with History? (…) argued that
exclusionary institutions set up during the European conquest
to exploit existing mineral wealth and indigenous populations,
and the particular crops suited to the region’s climate (such as
sugar plantations based on a slave workforce), led to highly
unequal access to land, education, and political power at least
until the late 1800s and thus had adverse consequences for
8growth and inequality for a long time,…”

Thus, the “new orthodoxy” has spread beyond the strictly
academic limits and might eventually bias future measures of
economic policy. That is the reason why the discussion of this subject
stirs up an additional interest as an adequate diagnosis is a necessary
–but not sufficient- condition for the solution to the problems of
several hundreds of millions of Latin Americans.



2. Brief description of the “new orthodoxy”


It is not easy to summarize in a few lines the ideas of
Engerman and Sokoloff (1994, 2002 y 2005). Certainly, these ideas
have been changing somewhat in the course of time, but there is a
central aspect in them. This is the decisive role assigned to extreme
inequality in explaining the economic differences between the ex-
British colonies in North America and the Spanish colonies in the rest
of the American continent.

In turn, the differences in equality would be in accordance with
those already existing in the initial endowment of factors in the
various colonies. Thus, the areas (the Caribbean and Brazil) with
favourable conditions for growing sugar cane or other that presented
scale economies would end up characterized by large
plantations based on the employment of slave labour and became
very unequal societies. Inequality in continental Hispanic America
arose from the abundance of indigenous population and from the
granting of lands, mineral deposits, native labour and taxes to the
colonial elite. These practices were influenced by pre-existing

8
Perry et al. (2006, pp. 2.3).
3 Mesoamerican and Andean institutions. The size of the elite was
limited by a restrictive immigration policy.

Contrarily, in the North American Eastern coast, the lesser
inequality resulted from the absence of an abundant indigenous
population and from local geographical features which made it
suitable only for small family-sized farming without significant
economies of scale. This greater equality promoted more democratic
political institutions, higher investment in public goods and
infrastructure, and a relatively easy access to property rights and
economic opportunities. All these circumstances promoted economic
growth and explain why Latin America fell so far behind North
America economically.

Therefore, according to Engerman and Sokoloff (1994, 2002
and 2005), the conditions prevailing originally in the colonial system
in America would exert an unavoidable influence during the following
centuries. The extremely long-lasting inertia of the most remote
colonial past, defined mainly in terms of its endowment of factors
towards 1500, is other of the central aspects in the works by these
authors.

While Engerman and Solkoloff (1994, 2002 y 2005) deal
preferably and almost exclusively with America, Acemoglu, Johnson
and Robinson (2001a and 2002) treat the subject of colonialism in a
more global manner. However, th