12,744 research outputs found
Improved zinc oxide thermal control coatings
Ferricyanide/ferrocyanide couple prevents zinc oxide pigment degradation in thermal control coatings. Chemical couple retards physical optical property changes
Dirac Monopoles and Witten's Monopole Equations
A simple solution of Witten's monopole equations is given.Comment: 3 pages. Late
Solutions without singularities in gauge theory of gravitation
A de-Sitter gauge theory of the gravitational field is developed using a
spherical symmetric Minkowski space-time as base manifold. The gravitational
field is described by gauge potentials and the mathematical structure of the
underlying space-time is not affected by physical events. The field equations
are written and their solutions without singularities are obtained by imposing
some constraints on the invariants of the model. An example of such a solution
is given and its dependence on the cosmological constant is studied. A
comparison with results obtained in General Relativity theory is also
presented.
Keywords: gauge theory, gravitation, singularity, computer algebraComment: 9 pages, no figure
Effect of environment on thermal control coatings
Ferrocyanide and ferricyanide additives for prevention of optical degradation of coatings by ultraviolet radiation and vacuu
Trading on time
The authors determine how time delays affect international trade using newly collected World Bank data on the days it takes to move standard cargo from the factory gate to the ship in 126 countries. They estimate a modified gravity equation, controlling for endogeneity and remoteness. On average, each additional day that a product is delayed prior to being shipped reduces trade by at least 1 percent. Put differently, each day is equivalent to a country distancing itself from its trade partners by 70 kilometers on average. Delays have an even greater impact on developing country exports and exports of time-sensitive goods, such as perishable agricultural products. In particular, a day's delay reduces a country's relative exports of time-sensitive to time-insensitive agricultural goods by 6 percent.Free Trade,Economic Theory&Research,Trade Policy,Common Carriers Industry,Transport and Trade Logistics
Statistical Mechanics of Linear and Nonlinear Time-Domain Ensemble Learning
Conventional ensemble learning combines students in the space domain. In this
paper, however, we combine students in the time domain and call it time-domain
ensemble learning. We analyze, compare, and discuss the generalization
performances regarding time-domain ensemble learning of both a linear model and
a nonlinear model. Analyzing in the framework of online learning using a
statistical mechanical method, we show the qualitatively different behaviors
between the two models. In a linear model, the dynamical behaviors of the
generalization error are monotonic. We analytically show that time-domain
ensemble learning is twice as effective as conventional ensemble learning.
Furthermore, the generalization error of a nonlinear model features
nonmonotonic dynamical behaviors when the learning rate is small. We
numerically show that the generalization performance can be improved remarkably
by using this phenomenon and the divergence of students in the time domain.Comment: 11 pages, 7 figure
- …