one of the most remarkable basis of the gravity data inversion is the recognition of sharp boundaries between an ore body and its host rocks during the interpretation step. therefore, in this work, it is attempted to develop an inversion approach to determine a 3d density distribution that produces a given gravity anomaly. the subsurface model consists of a 3d rectangular prisms of known sizes ...

In a quantum world, reference frames are ultimately systems too -- but what does it mean to "jump into the perspective of particle"? this work, we show that frame (QRF) transformations appear naturally as symmetries simple physical systems. This allows us rederive and generalize known QRF within an alternative, operationally transparent framework, shed new light on their structure interpretatio...

We prove that every semidefinite moment relaxation of a polynomial optimization problem (POP) with ball constraint can be reformulated as program involving matrix constant trace property (CTP). As result such relaxations solved efficiently by first-order methods exploit CTP, e.g., the conditional gradient-based augmented Lagrangian method. also extend this CTP-exploiting framework to large-scal...

Positive definite matrix approximation with a condition number constraint is an optimization problem to find the nearest positive definite matrix whose condition number is smaller than a given constant. We demonstrate that this problem can be converted to a simpler one in this note when we use a unitary similarity invariant norm as a metric. We can especially convert it to a univariate piecewis...

State covariances of linear systems satisfy certain constraints imposed by the underlying dynamics. These constraints dictate a particular structure of state covariances. However, sample covariances almost always fail to have the required structure. The renewed interest in using state covariances for estimating the power spectra of inputs gives rise to the approximation problem. In this note, t...

background: within the context of developing techniques to facilitate the diagnosis of the thyroid diseases, the elemental composition of pathological thyroid tissue (neoplastic and non-neoplastic) was investigated by proton induced x-ray emission. the pixe has been widely used as a sensitive technique for trace elemental analysis in both biological and medical fields. materials and methods: th...

wound healing in the skin depends upon the availability of appropriate trace metals as enzyme cofactors and structural components in tissue repair. the present study is a part of a series of experimental investigations to examine the influence of bentonite on skin wound healing. surgically induced skin wounds in 48 young adult male rats were exposed topically to bentonite (12 round wound and 12...

This paper presents an unsupervised relation extraction algorithm, which induces relations between entity pairs by grouping them into a “natural” number of clusters based on the similarity of their contexts. Stability-based criterion is used to automatically estimate the number of clusters. For removing noisy feature words in clustering procedure, feature selection is conducted by optimizing a ...

This paper studies matrix completion under a general sampling model using the max-norm as a convex relaxation for the rank of the matrix. The optimal rate of convergence is established for the Frobenius norm loss. It is shown that the max-norm constrained minimization method is rate-optimal and it yields a more stable approximate recovery guarantee, with respect to the sampling distributions, t...

Adding external knowledge improves the results for ill-posed problems. In this paper we present a new multi-level optimization framework for image registration when adding landmark constraints on the transformation. Previous approaches are based on a fixed discretization and lack of allowing for continuous landmark positions that are not on grid points. Our novel approach overcomes these proble...