6,507 research outputs found
The Grow-Shrink strategy for learning Markov network structures constrained by context-specific independences
Markov networks are models for compactly representing complex probability
distributions. They are composed by a structure and a set of numerical weights.
The structure qualitatively describes independences in the distribution, which
can be exploited to factorize the distribution into a set of compact functions.
A key application for learning structures from data is to automatically
discover knowledge. In practice, structure learning algorithms focused on
"knowledge discovery" present a limitation: they use a coarse-grained
representation of the structure. As a result, this representation cannot
describe context-specific independences. Very recently, an algorithm called
CSPC was designed to overcome this limitation, but it has a high computational
complexity. This work tries to mitigate this downside presenting CSGS, an
algorithm that uses the Grow-Shrink strategy for reducing unnecessary
computations. On an empirical evaluation, the structures learned by CSGS
achieve competitive accuracies and lower computational complexity with respect
to those obtained by CSPC.Comment: 12 pages, and 8 figures. This works was presented in IBERAMIA 201
Critical States Embedded in the Continuum
We introduce a class of critical states which are embedded in the continuum
(CSC) of one-dimensional optical waveguide array with one non-Hermitian defect.
These states are at the verge of being fractal and have real propagation
constant. They emerge at a phase transition which is driven by the imaginary
refractive index of the defect waveguide and it is accompanied by a mode
segregation which reveals analogies with the Dicke super -radiance. Below this
point the states are extended while above they evolve to exponentially
localized modes. An addition of a background gain or loss can turn these
localized states to bound states in the continuum.Comment: 4.5 pages, 3 figures, 1 page of supplementary material including one
figur
Homogeneous Charge Compression Ignition Control by the Use of Plasmatron Fuel Converter Technology
Response of discrete nonlinear systems with many degrees of freedom
We study the response of a large array of coupled nonlinear oscillators to
parametric excitation, motivated by the growing interest in the nonlinear
dynamics of microelectromechanical and nanoelectromechanical systems (MEMS and
NEMS). Using a multiscale analysis, we derive an amplitude equation that
captures the slow dynamics of the coupled oscillators just above the onset of
parametric oscillations. The amplitude equation that we derive here from first
principles exhibits a wavenumber dependent bifurcation similar in character to
the behavior known to exist in fluids undergoing the Faraday wave instability.
We confirm this behavior numerically and make suggestions for testing it
experimentally with MEMS and NEMS resonators.Comment: Version 2 is an expanded version of the article, containing detailed
steps of the derivation that were left out in version 1, but no additional
result
Tax Treatment of a Marijuana Business
Currently, twenty-eight states and the District of Columbia allow the use of marijuana for medical purposes and permit the conduct of a business marketing of marijuana for that purpose. Eight of those states and the District of Columbia permit the recreational use of marijuana. There is reason to believe that more states will decriminalize the marketing of marijuana. However, marijuana is listed in Schedule 1 of the federal Controlled Substances Act of 1970 (CSA) which makes it illegal under federal law to manufacture or distribute marijuana even when it is legal to do so under local state law. In a series of memoranda promulgated by the Justice Department in the period from 2009 to 2014, the Department announced that it would not enforce the CSA prohibition against marijuana if certain requirements are met. Consequently, even the federal government has evidenced some ambivalence as to whether the conduct of a marijuana business for medical use should be illegal
Provisions Denying a Deduction for Illegal Expenses and Expenses of an Illegal Business Should be Repealed
The federal income tax law denies a deduction for illegal expenses, for any expense (legal or otherwise) of an illegal business that is trafficking in controlled substances, for losses incurred in an unlawful activity, and for bribes, kickbacks, and rebates connected with the Medicare or Medicaid program. In this Article, the authors first describe the current treatment of those items by the tax law. The Article next explains that the current treatment constitutes a penalty for the taxpayer whose deduction is denied, and then explores why such a penalty is bad policy and conflicts with the traditional purposes and goals of punishing wrongful behavior. The principal objection to the penalty imposed by the tax law’s denial of deductions for business and profit-oriented expenses is that the manner in which the size of the tax law’s penalty is determined is completely arbitrary and bears no relationship to the seriousness of the crime or the conditions under which it was committed. Another objection to the penalty is that it would be litigated in a civil tax suit in which the taxpayer would lack the protections and rights accorded to criminal defendants even though it constitutes a punishment for criminal behavior. The penalty is especially harsh as applied to the legal expenses of a marijuana business under a more stringent Code provision given the decriminalization of marijuana by many states. The Article also contends that the denial of a deduction for unlawful medical expenses conflicts with the principle allowing the patient a deduction for whatever treatment the patient chooses so long as it is based on a bona fide effort to deal with the illness. The authors recommend that Congress act to eliminate all of these tax penalties
Provisions Denying a Deduction for Illegal Expenses and Expenses of an Illegal Business Should Be Repealed
Currently, the tax law denies a deduction for business expenses that violate a federal or state law (but only if the state law is generally enforced). In addition, losses, including business losses, cannot be deducted if they arise out of an illegal activity. For example, medical expenses are denied a deduction if they are illegal. Kickbacks, bribes, and rebates given in connection with the Medicaid or Medicare program are nondeductible. Any expenses, legal or not, incurred in connection with the conduct of a business of selling a controlled substance that is prohibited by federal law (or by the law of the state in which the business is conducted) cannot be deducted. It is the contention of the authors that all of those provisions should be repealed and that there should be no restriction on the deductibility of an expense because of its illegality or its connection with an illegal activity. The authors will show in this Article that the current treatment is bad policy and not in accord with the traditional rationale for meting out punishment
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