Graph Sparsification by Edge-Connectivity and Random Spanning Trees

We present new approaches to constructing graph sparsifiers --- weighted subgraphs for which every cut has the same value as the original graph, up to a factor of $(1 \pm \epsilon)$. Our first approach independently samples each edge $uv$ with probability inversely proportional to the edge-connectivity between $u$ and $v$. The fact that this approach produces a sparsifier resolves a question posed by Bencz\'ur and Karger (2002). Concurrent work of Hariharan and Panigrahi also resolves this question. Our second approach constructs a sparsifier by forming the union of several uniformly random spanning trees. Both of our approaches produce sparsifiers with $O(n \log^2(n)/\epsilon^2)$ edges. Our proofs are based on extensions of Karger's contraction algorithm, which may be of independent interest

Three dimensional global modeling of atmospheric CO2

A model was developed to study the prospects of extracting information on carbon dioxide sources and sinks from observed CO2 variations. The approach uses a three dimensional global transport model, based on winds from a 3-D general circulation model (GCM), to advect CO2 noninteractively, i.e., as a tracer, with specified sources and sinks of CO2 at the surface. The 3-D model employed is identified and biosphere, ocean and fossil fuel sources and sinks are discussed. Some preliminary model results are presented

The recovery of microwave scattering parameters from scatterometric measurements with special application to the sea

As part of an effort to demonstrate the value of the microwave scatterometer as a remote sea wind sensor, the interaction between an arbitrarily polarized scatterometer antenna and a noncoherent distributive target was derived and applied to develop a measuring technique to recover all the scattering parameters. The results are helpful for specifying antenna polarization properties for accurate retrieval of the parameters not only for the sea but also for other distributive scenes

Will GATT enforcement control antidumping?

The authors try to gauge why the GATT dispute settlement process has, to date, been so ineffective in disciplining the use of antidumping measures. Focusing on the five cases in which panels have completed their findings and recommendations, the authors identify the sources of this ineffectiveness and evaluate the likelihood that the process will become effective. Changing the bureaucratic momentum of the system is possible, they contend, but would not be easy. It would require greater resolve by member countries'GATT delegates to see that GATT rules are enforced - a greater willingness to stand up to domestic pressures to bend GATT rules to suit the demands of national politics. Changing the legal momentum of the system will be even more difficult, say the authors. Interpreting the GATT in a legalistic way compels one to interpret it as a statement of rights to impose antidumping duties. The substantive criteria for action are broad: the injury concept justifies protection for anyone to whom it is worth the time to ask for it. The constraints onantidumping actions - loopholes and procedural technicalities - are artificial, so legal reform means getting rid of them. Where do the GATT articles on trade remedies lead? The authors contend that if you take a legalistic view, you come to a protectionist conclusion.TF054105-DONOR FUNDED OPERATION ADMINISTRATION FEE INCOME AND EXPENSE ACCOUNT,Globalization and Financial Integration,Environmental Economics&Policies,Transport and Trade Logistics,Common Carriers Industry

Can competition policy control"301"?

Should fair trade rules be replaced by national or international competition rules? A familiar argument for doing so is that more rigorously enforced competition standards might eliminate the basis for the burgeoning number of antidumping cases of recent years. A less familiar argument is that the implementation of internationally agreed competition standards might reduce the frequency with which the U.S government uses section 301 of U.S. trade law. Section 301 lists foreign government toleration of systematic anticompetitive activities as one of the bases for taking retaliatory action against foreign uncompetitive practices but were taken up through other mechanisms; extraterritorial application of U.S. antitrust law or direct negotiations sometimes capped by an understanding at the presidential level. These negotiations often included the threat of initiation of antidumping,"301,"or other trade remedies cases. (The structuralimpediments initiative negotiations with Japan are the most familiar example.) In several of these cases, the foreign government agreed to and implemented more rigorous antitrust enforcement, but these actions seldom ended the dispute. The U.S. government pressed on for tangible evidence of increased U.S. export sales. The authors conclude that removing the basis for these disputes -- alleged lax enforcement of competition policy -- did not remove the motive for them -- increased U.S. exports. Competition policy then is not the antidote for"301."The last section of the paper reviews the compatibility of"301"with the preservation of open international trading system. Of 70"301"cases (through December 31, 1992) that have led to policy changes, 52 have led to liberalizations, and only 18 have led to increased trade restrictions. Viewed from the point of view of results, the major shortcoming of"301"is that the United States is the only country whose policies do not come under its scrutiny.TF054105-DONOR FUNDED OPERATION ADMINISTRATION FEE INCOME AND EXPENSE ACCOUNT,Access to Markets,Markets and Market Access,Environmental Economics&Policies,National Governance