Post-stack velocity analysis in the dip-angle domain using diffractions     

Moshe Reshef  Evgeny Landa 《Geophysical Prospecting》2009,57(5):811-821

Interval velocity analysis in complex geological areas is often considered as an unresolved problem. A novel approach to improve the velocity analysis process is to perform the analysis in a non-conventional domain and to use seismic events that are usually ignored during standard data processing and imaging. In this study, a method to analyse diffraction data for migration velocity analysis in the time- or depth-domain is presented. The method is based on the clear distinction between diffractions and reflections in the post-migration dip-angle domain. The attractive possibility to perform the analysis, using only stacked data as an input, is demonstrated on synthetic and real data examples.  相似文献   

Bipolar outflow on the asymptotic giant branch – the case of IRC+10011     

Dejan Vinkovi&#;  Thomas Blöcker  Karl-Heinz Hofmann  Moshe Elitzur  Gerd Weigelt 《Monthly notices of the Royal Astronomical Society》2004,352(3):852-862

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Spectral Line and Continuum Radiation Propagation in a Clumpy Medium     

John Conway  Moshe Elitzur  Rodrigo Parra 《Astrophysics and Space Science》2005,295(1-2):319-324

We discuss the propagation of spectral line and continuum radiation in a clumpy medium and give general expressions for the observed absorption or emission from a cloud population. We show that the affect of the medium clumpiness can usually be characterised by a single number multiplying the mean column opacity. Our result provides a simpler proof and generalization of the result of Martin et al. (1984). The formalism provides a simple way to understand the effects of clumping on molecular line profiles and ratios; for example, how clumping effects the interpretation of ¹³CO(1–0) to ¹²CO(1–0) line ratios. It also can be used as a propagation operator in physical models of clumpy media where the incident radiation effects the spectral line emissivity. We are working to extend the formalism to the propagation of masers in a clumpy medium, but in this case, there are special difficulties because formal expectation values are not characteristic of observations because they are biased by rare events.  相似文献   

Dynamic programming and the principle of optimality: A systematic approach     

Moshe Sniedovich 《Advances in water resources》1978,1(4):183-190

The dynamic programming recursive procedure has provided an efficient method for solving a variety of sequential decision problems related to water resources systems. In many investigations Bellman's principle of optimality is used as a proof for the optimality of the dynamic programming solutions. In this paper the dynamic programming procedure is systematically studied so as to clarify the relationship between Bellman's principle of optimality and the optimality of the dynamic programming solutions.Our main result is that although the principle is valid, in order to use it as a proof for the optimality of the dynamic programming solution certain modeling requirements should be met.The mathematical model presented in this paper provides a convenient framework for the modeling and analysis of dynamic programming problems encountered by in water resources management studies.The results derived here resolve few of the fundamental questions raised in the literature regarding the validity of Bellman's principle of oplimality and the optimality of the dynamic programming solutions.  相似文献   

The importance of health co-benefits in macroeconomic assessments of UK Greenhouse Gas emission reduction strategies     

Henning Tarp Jensen  Marcus R. Keogh-Brown  Richard D. Smith  Zaid Chalabi  Alan D. Dangour  Mike Davies  Phil Edwards  Tara Garnett  Moshe Givoni  Ulla Griffiths  Ian Hamilton  James Jarrett  Ian Roberts  Paul Wilkinson  James Woodcock  Andy Haines 《Climatic change》2013,119(2):223-237

We employ a single-country dynamically-recursive Computable General Equilibrium model to make health-focussed macroeconomic assessments of three contingent UK Greenhouse Gas (GHG) mitigation strategies, designed to achieve 2030 emission targets as suggested by the UK Committee on Climate Change. In contrast to previous assessment studies, our main focus is on health co-benefits additional to those from reduced local air pollution. We employ a conservative cost-effectiveness methodology with a zero net cost threshold. Our urban transport strategy (with cleaner vehicles and increased active travel) brings important health co-benefits and is likely to be strongly cost-effective; our food and agriculture strategy (based on abatement technologies and reduction in livestock production) brings worthwhile health co-benefits, but is unlikely to eliminate net costs unless new technological measures are included; our household energy efficiency strategy is likely to breakeven only over the long term after the investment programme has ceased (beyond our 20 year time horizon). We conclude that UK policy makers will, most likely, have to adopt elements which involve initial net societal costs in order to achieve future emission targets and longer-term benefits from GHG reduction. Cost-effectiveness of GHG strategies is likely to require technological mitigation interventions and/or demand-constraining interventions with important health co-benefits and other efficiency-enhancing policies that promote internalization of externalities. Health co-benefits can play a crucial role in bringing down net costs, but our results also suggest the need for adopting holistic assessment methodologies which give proper consideration to welfare-improving health co-benefits with potentially negative economic repercussions (such as increased longevity).  相似文献   

Quantitative immunochemical evaluation of fish metallothionein upon exposure to cadmium   总被引：1，自引：0，他引：1  

Yudkovski Y  Rogowska-Wrzesinska A  Yankelevich I  Shefer E  Herut B  Tom M 《Marine environmental research》2008,65(5):427-436

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A new exact method for line radiative transfer   总被引：1，自引：0，他引：1  

Moshe Elitzur  Andrés Asensio Ramos 《Monthly notices of the Royal Astronomical Society》2006,365(3):779-791

We present a new method, the coupled escape probability (CEP), for exact calculation of line emission from multi-level systems, solving only algebraic equations for the level populations. The CEP formulation of the classical two-level problem is a set of linear equations , and we uncover an exact analytic expression for the emission from two-level optically thick sources that holds as long as they are in the 'effectively thin' regime. In a comparative study of a number of standard problems, the CEP method outperformed the leading line transfer methods by substantial margins.
The algebraic equations employed by our new method are already incorporated in numerous codes based on the escape probability approximation. All that is required for an exact solution with these existing codes is to augment the expression for the escape probability with simple zone-coupling terms. As an application, we find that standard escape probability calculations generally produce the correct cooling emission by the C  ii 158-μm line but not by the ³P lines of O  i .  相似文献   

Generalized Multipolar Ray Theory for Surface and Shallow Sources     

Moshe Vered  Ari Ben-Menahem 《Geophysical Journal International》1976,45(1):195-198

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Geography in Israel     

Moshe Brawer  Elisha Efrat 《GeoJournal》1978,2(6):496-498

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Changes in the Earth's Inertia Tensor due to Earthquakes by MacCullagh's formula     

Moshe Israel  Ari Ben-Menahem 《Geophysical Journal International》1975,40(2):305-307

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