(Psycho-)Analysis of Benchmark Experiments

It is common knowledge that certain characteristics of data sets -- such as linear separability or sample size -- determine the performance of learning algorithms. In this paper we propose a formal framework for investigations on this relationship. The framework combines three, in their respective scientific discipline well-established, methods. Benchmark experiments are the method of choice in machine and statistical learning to compare algorithms with respect to a certain performance measure on particular data sets. To realize the interaction between data sets and algorithms, the data sets are characterized using statistical and information-theoretic measures; a common approach in the field of meta learning to decide which algorithms are suited to particular data sets. Finally, the performance ranking of algorithms on groups of data sets with similar characteristics is determined by means of recursively partitioning Bradley-Terry models, that are commonly used in psychology to study the preferences of human subjects. The result is a tree with splits in data set characteristics which significantly change the performances of the algorithms. The main advantage is the automatic detection of these important characteristics. The framework is introduced using a simple artificial example. Its real-word usage is demonstrated by means of an application example consisting of thirteen well-known data sets and six common learning algorithms. All resources to replicate the examples are available online

Getting It Right: Employment Subsidy or Minimum Wage?

In monopsony models of the labour market either a minimum wage or an employment subsidy financed by a lump sum tax on profits can achieve the efficient level of employment and output. Incorporating working conditions into a monopsony model where higher wages raise firm labour supply, but less attractive working conditions reduce it, changes these policy implications. Specifically, a minimum wage policy could, in contrast to an employment subsidy, cause working conditions to deteriorate and welfare to fall. Empirical evidence from the Republic of Trinidad and Tobago shows that a minimum wage may indeed cause working conditions to worsen

Efficiency Wages and Effort: Are Hard Jobs Better?

Efficiency wage theory predicts that the wage per unit of effort will be lower in intensively monitored sectors. This wage differential will increase in effort. Using employer-employee matched data from Ghana we provide evidence supporting this hypothesis

The formal sector wage premium and firm size

We show theoretically that when larger firms pay higher wages and are more likely to be caught defaulting on labour taxes, then large high-wage firms will be in the formal sector and small low-wage firms will be in the informal sector. The formal sector wage premium is thus just a firm size wage differential. Using data from the South African labour force survey we illustrate that firm size is indeed the key variable determining whether a formal sector premium exists

Symplectic Cuts and Projection Quantization

The recently proposed projection quantization, which is a method to quantize particular subspaces of systems with known quantum theory, is shown to yield a genuine quantization in several cases. This may be inferred from exact results established within symplectic cutting.Comment: 12 pages, v2: additional examples and a new reference to related wor

Group Theoretical Quantization of a Phase Space S1xR+S^{1} x R^{+} and the Mass Spectrum of Schwarzschild Black Holes in D Space-Time Dimensions

The symplectic reduction of pure spherically symmetric (Schwarzschild) classical gravity in D space-time dimensions yields a 2-dimensional phase space of observables consisting of the Mass M (>0) and a canonically conjugate (Killing) time variable T. Imposing (mass-dependent) periodic boundary conditions in time on the associated quantum mechanical plane waves which represent the Schwarzschild system in the period just before or during the formation of a black hole, yields an energy spectrum of the hole which realizes the old Bekenstein postulate that the quanta of the horizon A_{D-2} are multiples of a basic area quantum. In the present paper it is shown that the phase space of such a Schwarzschild black hole in D space-time dimensions is symplectomorphic to a symplectic manifold S={(phi in R mod 2 pi, p = A_{D-2} >0)} with the symplectic form d phi wedge d p. As the action of the group SO_+(1,2) on that manifold is transitive, effective and Hamiltonian, it can be used for a group theoretical quantization of the system. The area operator p for the horizon corresponds to the generator of the compact subgroup SO(2) and becomes quantized accordingly: The positive discrete series of the irreducible unitary representations of SO_+(1,2) yields an (horizon) area spectrum proportional k+n, where k = 1,2,... characterizes the representation and n = 0,1,2,... the number of area quanta. If one employs the unitary representations of the universal covering group of SO_+(1,2) the number k can take any fixed positive real value (theta-parameter). The unitary representations of the positive discrete series provide concrete Hilbert spaces for quantum Schwarzschild black holes

Why do foreign-owned-firms pay more? The role of on-the-job training

Foreign-owned firms have consistently been found to pay higher wages than domestic firms to what appear to be equally productive workers in both developed and developing countries alike. Although a number of studies have documented and some attempted to explain this stylized fact, the issue still remains unresolved. In a multi-period bargaining framework we show that if firm specific training is more productive in foreign firms, foreign firm workers will have a steeper wage profile and thus acquire a premium over time. Using a rich employeremployee matched data set we show that the foreign wage premium is only acquired by workers over time spent in the firm and only by those that receive on the job training, thus providing empirical support for a firm specific human capital acquisition explanation

Why do foreign-owned firms pay more? The role of on-the-job training

Foreign-owned firms have consistently been found to pay higher wages than domestic firms to what appear to be equally productive workers in both developed and developing countries alike. Although a number of studies have documented and some attempted to explain this stylized fact, the issue still remains unresolved. In a multi-period bargaining framework we show that if firm specific training is more productive in foreign firms, foreign firm workers will have a steeper wage profile and thus acquire a premium over time. Using a rich employer-employee matched data set for Ghana manufacturing we show that the foreign wage premium is only acquired by workers over time spent in the firm and only by those that receive on the job training, thus providing empirical support for a firm specific human capital acquisition explanation

Algebroid Yang-Mills Theories

A framework for constructing new kinds of gauge theories is suggested. Essentially it consists in replacing Lie algebras by Lie or Courant algebroids. Besides presenting novel topological theories defined in arbitrary spacetime dimensions, we show that equipping Lie algebroids E with a fiber metric having sufficiently many E-Killing vectors leads to an astonishingly mild deformation of ordinary Yang-Mills theories: Additional fields turn out to carry no propagating modes. Instead they serve as moduli parameters gluing together in part different Yang-Mills theories. This leads to a symmetry enhancement at critical points of these fields, as is also typical for String effective field theories.Comment: 4 pages; v3: Minor rewording of v1, version to appear in Phys. Rev. Let