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Yossi Azar Martin Hoefer Idan Maor Rebecca Reiffenhäuser Berthold Vöcking 《Mathematical Programming》2017,163(1-2):445-469
A powerful algorithmic technique for truthful mechanism design is the maximal-in-distributional-range (MIDR) paradigm. Unfortunately, many such algorithms use heavy algorithmic machinery, e.g., the ellipsoid method and (approximate) solution of convex programs. In this paper, we present a correlated rounding technique for designing mechanisms that are truthful in expectation. It is elementary and can be implemented quickly. The main property we rely on is that the domain offers fractional optimum solutions with a tree structure. In auctions based on the generalized assignment problem, each bidder has a publicly known knapsack constraint that captures the subsets of items that are of value to him. He has a private valuation for each item and strives to maximize the value of assigned items minus payment. For this domain we design a truthful 2-approximate MIDR mechanism for social welfare maximization. It avoids using the ellipsoid method or convex programming. In contrast to some previous work, our mechanism achieves exact truthfulness. In restricted-related scheduling with selfish machines, each job comes with a public weight, and it must be assigned to a machine from a public job-specific subset. Each machine has a private speed and strives to maximize payments minus workload of jobs assigned to it. Here we design a mechanism for makespan minimization. This is a single-parameter domain, but the approximation status of the optimization problem is similar to unrelated machine scheduling: The best known algorithm obtains a (non-truthful) 2-approximation for unrelated machines, and there is 1.5-hardness. Our mechanism matches this bound with a truthful 2-approximation. 相似文献
3.
Nonlinear Dynamics - Hybrid vibro-impact (HVI) oscillations is a strongly nonlinear dynamical regime that involves both linear oscillations and collisions under periodic, impulsive, or stochastic... 相似文献
4.
Approach to equilibrium charge distribution in single, small impact parameter collisions of S projectiles with rare gases has been observed. Average charges generally agree with the dynamic screening model, but in the S + Xe system they are raised by promotion effects. 相似文献
5.
A comparative investigation of various pomeron models is carried out through the study of their predicted values of tot,B, and
in high energypp and
scattering. Our results strongly support a picture of the pomeron in which we have both moderate blackening and expansion of the
amplitude in impact parameter space as a function of energy in the ISR-SSC domain. Our analysis shows the data is compatible with a hybrid eikonal model which combines the hard Lipatovlike QCD pomeron with the old fashioned soft pomeron and Regge terms. We show that the additive quark model, at least in the naive form, is not compatible with the data.Work supported in part by Israel Academy of Sciences and Humanities 相似文献
6.
I. Perelshtein N. Perkas Sh. Magdassi T. Zioni M. Royz Z. Maor A. Gedanken 《Journal of nanoparticle research》2008,10(1):191-195
A new method of dispersing the aggregated strontium hexaferrite (SrFe12O19) magnetic nanoparticles in organic solvents such as propylene glycol monomethyl ether acetate (PGMEA), propylene glycol (PG),
and glycerol, by an ultrasonic bath is reported herein. The particles size of SrFe12O19 after treatment with the PGMEA is in the range 70–100 nm. The structure of dispersed SrFe12O19 was characterized using transmission electron microscopy (TEM), high resolution scanning electron microscopy (HR SEM) and
thermo gravimetric analysis (TGA). This dispersed material was used for the preparation of a topical magnetic cosmetic product
as follows: The dispersion of SrFe12O19 in PG was mixed with “Dermud-Ahava Body Cream”, an ‘oil in water’ emulsion of a Dead Sea mineral cosmetic, “AHAVA”, and the
magnetic properties of the created composite were determined. The ferrimagnetic behavior of the composite has been demonstrated
as being very similar to the behavior of strontium hexaferrite itself. 相似文献
7.
Pion-exchange contributions to inclusive reactions in the fragmentation domain are discussed and the importance of introducing absorptive corrections is stressed. An explicit model which incorporates the absorptive two-body correction is suggested and its experimental implications are examined. 相似文献
8.
We propose a modified version of the Balitsky–Kovchegov (BK) evolution equation, which includes the main NLO corrections. We use the result that the main NLO corrections to the BFKL kernel are the LO DGLAP corrections. We present a numerical solution of the modified non-linear equation, and compare with the solution of the unmodified BK equation. We show that the saturation momentum has a sharp increase in the LHC energy range. Our numerical solution indicates that the influence of the preasymptotic corrections, related to the full anomalous dimensions of the DGLAP equation, are rather large. These corrections moderate the energy behavior of the amplitude, as well as the value of the saturation scale. All our calculations are made with a fixed value of S. 相似文献
9.
W. A. Schönfeldt P. H. Mokler D. Maor 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1988,9(1):47-57
Cross sections for the electron transfer from neutral Kr atoms to highly charged Ni q+ projectiles were measured at 1.4 MeV/u. Estimates on the contributions of single and double capture into the Ni-L shell and into excited states are extracted from measured cross sections for the Ni-L x-ray emission for incoming projectileL vacancies (q≧19). The role of metastable states produced in the capture process is analysed. We find that most of the capture directly populates the Ni-L shell, and the capture into excited states seems to be dominated by two-electron capture. The electrons involved in double transfer processes seem to be strongly correlated. An increase in the low-probability non-correlated double transfer with increasing number of incomingL-vacancies is indicated by the data. 相似文献
10.
E. Gotsman A. Kormilitzin E. Levin U. Maor 《The European Physical Journal C - Particles and Fields》2007,52(2):295-304
Based on the calculation of survival probabilities, we suggest a procedure to assess the value of G3P, the triple pomeron ‘bare’ coupling constant, by comparing the large rapidity gap single high mass diffraction data in proton–proton
scattering and J/Ψ photo and DIS production. For p–p scattering the calculation in a three amplitude rescattering eikonal
model predicts the survival probability to be an order of magnitude smaller than for the two amplitude case. The calculations
of the survival probabilities for photo and DIS J/Ψ production are made in a dedicated model. In this process we show that,
even though its survival probability is considerably larger than in p–p scattering, its value is below unity and cannot be
neglected in the data analysis. We argue that, regardless of the uncertainties in the suggested procedures, the outcome is
important, both with regards to a realistic estimate of G3P and to the survival probabilities relevant to LHC experiments.
PACS 13.85-t; 13.85.Hd; 11.55.-m; 11.55.Bq 相似文献