MIT Open Access Articles
http://hdl.handle.net/1721.1/49433
Tue, 20 Mar 2018 20:17:44 GMT2018-03-20T20:17:44ZIndividual Heterogeneity and Average Welfare
http://hdl.handle.net/1721.1/114243
Individual Heterogeneity and Average Welfare
Hausman, Jerry A; Newey, Whitney K
Individual heterogeneity is an important source of variation in demand. Allowing for general heterogeneity is needed for correct welfare comparisons. We consider general heterogeneous demand where preferences and linear budget sets are statistically independent. Only the marginal distribution of demand for each price and income is identified from cross-section data where only one price and income is observed for each individual. Thus, objects that depend on varying price and/or income for an individual are not generally identified, including average exact consumer surplus. We use bounds on income effects to derive relatively simple bounds on the average surplus, including for discrete/continuous choice. We also sketch an approach to bounding surplus that does not use income effect bounds. We apply the results to gasoline demand. We find tight bounds for average surplus in this application, but wider bounds for average deadweight loss.
Sun, 01 May 2016 00:00:00 GMThttp://hdl.handle.net/1721.1/1142432016-05-01T00:00:00ZStructure and conformational dynamics of scaffolded DNA origami nanoparticles
http://hdl.handle.net/1721.1/114242
Structure and conformational dynamics of scaffolded DNA origami nanoparticles
Pan, Keyao; Bricker, William P; Ratanalert, Sakul; Bathe, Mark
Synthetic DNA is a highly programmable nanoscale material that can be designed to self-assemble into 3D structures that are fu lly determined by underlying Watson-Crick base pairing. The double crossover (DX) design motif has demonstrated versatility in synthesizing arbitrary DNA nanoparticles on the 5- 100 nm scale for diverse applications in biotechnology. Prior computational investigations of these assemblies include all-atom and coarse-grained modeling, but modeling their conformational dynamics remains challenging due to their long relaxation times and associated computational cost. We apply all-atom molecular dynamics and coarse-grained finite element modeling to DX-based nanoparticles to elucidate their fine-scale and global conformational structure and dynamics. We use our coarsegrained model with a set of secondary structural motifs to predict the equilibrium solution structures of 45 DX-based DNA origami nanoparticles including a tetrahedron, octahedron, icosahedron, cuboctahedron and reinforced cube. Coarse-grained models are compared with 3D cryo-electron microscopy density maps for these five DNA nanoparticles and with all-atom molecular dynamics simulations for the tetrahedron and octahedron. Our results elucidate non-intuitive atomic-level structural details of DXbased DNA nanoparticles, and offer a general framework for efficient computational prediction of global and local structural andmechanical properties of DXbased assemblies that are inaccessible to all-atom based models alone.
Thu, 01 Jun 2017 00:00:00 GMThttp://hdl.handle.net/1721.1/1142422017-06-01T00:00:00ZReconstructing Markov processes from independent and anonymous experiments
http://hdl.handle.net/1721.1/114241
Reconstructing Markov processes from independent and anonymous experiments
Micali, Silvio; Zhu, Zeyuan Allen
We investigate the problem of exactly reconstructing, with high confidence and up to isomorphism, the ball of radius r centered at the starting state of a Markov process from independent and anonymous experiments. In an anonymous experiment, the states are visited according to the underlying transition probabilities, but no global state names are known: one can only recognize whether two states, reached within the same experiment, are the same. We prove quite tight bounds for such exact reconstruction in terms of both the number of experiments and their lengths. Keywords: Graph reconstruction; Random walk; Markov process; Local algorithms
Mon, 01 Feb 2016 00:00:00 GMThttp://hdl.handle.net/1721.1/1142412016-02-01T00:00:00ZA new method to distinguish hadronically decaying boosted Z bosons from W bosons using the ATLAS detector
http://hdl.handle.net/1721.1/114240
A new method to distinguish hadronically decaying boosted Z bosons from W bosons using the ATLAS detector
ATLAS Collaboration; Taylor, Frank E
The distribution of particles inside hadronic jets produced in the decay of boosted W and Z bosons can be used to discriminate such jets from the continuum background. Given that a jet has been identified as likely resulting from the hadronic decay of a boosted W or Z boson, this paper presents a technique for further differentiating Z bosons from W bosons. The variables used are jet mass, jet charge, and a b-tagging discriminant. A likelihood tagger is constructed from these variables and tested in the simulation of W ′ → WZ for bosons in the transverse momentum range 200 GeV < pT < 400 GeV in √s = 8 TeV pp collisions with the ATLAS detector at the LHC. For Z-boson tagging efficiencies of ϵZ = 90 , 50, and 10 % , one can achieve W + -boson tagging rejection factors (1 / ϵW + ) of 1.7, 8.3 and 1000, respectively. It is not possible to measure these efficiencies in the data due to the lack of a pure sample of high pT , hadronically decaying Z bosons. However, the modelling of the tagger inputs for boosted W bosons is studied in data using a tt¯ -enriched sample of events in 20.3 fb - 1 of data at √s= 8 TeV. The inputs are well modelled within uncertainties, which builds confidence in the expected tagger performance.
Fri, 01 Apr 2016 00:00:00 GMThttp://hdl.handle.net/1721.1/1142402016-04-01T00:00:00Z