6,922 research outputs found
Efficient estimation of Banach parameters in semiparametric models
Consider a semiparametric model with a Euclidean parameter and an
infinite-dimensional parameter, to be called a Banach parameter. Assume: (a)
There exists an efficient estimator of the Euclidean parameter. (b) When the
value of the Euclidean parameter is known, there exists an estimator of the
Banach parameter, which depends on this value and is efficient within this
restricted model. Substituting the efficient estimator of the Euclidean
parameter for the value of this parameter in the estimator of the Banach
parameter, one obtains an efficient estimator of the Banach parameter for the
full semiparametric model with the Euclidean parameter unknown. This hereditary
property of efficiency completes estimation in semiparametric models in which
the Euclidean parameter has been estimated efficiently. Typically, estimation
of both the Euclidean and the Banach parameter is necessary in order to
describe the random phenomenon under study to a sufficient extent. Since
efficient estimators are asymptotically linear, the above substitution method
is a particular case of substituting asymptotically linear estimators of a
Euclidean parameter into estimators that are asymptotically linear themselves
and that depend on this Euclidean parameter. This more general substitution
case is studied for its own sake as well, and a hereditary property for
asymptotic linearity is proved.Comment: Published at http://dx.doi.org/10.1214/009053604000000913 in the
Annals of Statistics (http://www.imstat.org/aos/) by the Institute of
Mathematical Statistics (http://www.imstat.org
Impact of Balance Of System (BOS) costs on photovoltaic power systems
The Department of Energy has developed a program to effect a large reduction in the price of photovoltaic modules, with significant progress already achieved toward the 1986 goal of 50 cents/watt (1975 dollars). Remaining elements of a P/V power system (structure, battery storage, regulation, control, and wiring) are also significant cost items. The costs of these remaining elements are commonly referred to as Balance-of-System (BOS) costs. The BOS costs are less well defined and documented than module costs. The Lewis Research Center (LeRC) in 1976/77 and with two village power experiments that will be installed in 1978. The costs were divided into five categories and analyzed. A regression analysis was performed to determine correlations of BOS Costs per peak watt, with power size for these photovoltaic systems. The statistical relationship may be used for flat-plate, DC systems ranging from 100 to 4,000 peak watts. A survey of suppliers was conducted for comparison with the predicted BOS cost relationship
Irreversibility line and low-field grain-boundary pinning in electron-doped superconducting thin films
AC magnetic susceptibilities of electron-doped Pr_{1.85}Ce_{0.15}CuO_4 (PCCO)
and Sm_{1.85}Ce_{0.15}CuO_4 (SCCO) granular thin films have been measured as a
function of temperature and magnetic-field strength. Depending on the level of
homogeneity of our films, two different types of the irreversibility line (IL)
defined as the intergrain-loss peak temperature in the imaginary part of
susceptibility have been found. The obtained results are described via the
critical-state model taking into account the low-field grain-boundary pinning.
The extracted pinning-force densities in more granular SCCO films turn out to
be four times larger than their counterparts in less granular PCCO films
Compendium of Applications Technology Satellite user experiments
The achievements of the user experiments performed with ATS satellites from 1967 to 1973 are summarized. Included are fixed and mobile point to point communications experiments involving voice, teletype and facsimile transmissions. Particular emphasis is given to the Alaska and Hawaii satellite communications experiments. The use of the ATS satellites for ranging and position fixing of ships and aircraft is also covered. The structure and operating characteristics of the various ATS satellite are briefly described
Photovoltaic power systems for rural areas of developing countries
Systems technology, reliability, and present and projected costs of photovoltaic systems are discussed using data derived from NASA, Lewis Research Center experience with photovoltaic systems deployed with a variety of users. Operating systems in two villages, one in Upper Volta and the other in southwestern Arizona are described. Energy cost comparisons are presented for photovoltaic systems versus alternative energy sources. Based on present system technology, reliability, and costs, photovoltaics provides a realistic energy option for developing nations
Patent Institutions: Shifting Interactions Between Legal Actors
This contribution to the Research Handbook on Economics of Intellectual Property Rights (Vol. 1 Theory) addresses interactions between the principal legal institutions of the U.S. patent system. It considers legal, strategic, and normative perspectives on these interactions as they have evolved over the last 35 years. Early centralization of power by the U.S. Court of Appeals for the Federal Circuit, newly created in 1982, established a regime dominated by the appellate court\u27s bright-line rules. More recently, aggressive Supreme Court and Congressional intervention have respectively reinvigorated patent law standards and led to significant devolution of power to inferior tribunals, including newly created tribunals like the USPTO\u27s Patent Trial and Appeals Board. This new era in institutional interaction creates a host of fresh empirical and normative research questions for scholars. The contribution concludes by outlining a research agenda
Emergence of the Shackleton Range from beneath the Antarctic Ice Sheet due to glacial erosion
This paper explores the long-term evolution of a subglacial fjord landscape in the Shackleton Range, Antarctica. We propose that prolonged ice-sheet erosion across a passive continental margin caused troughs to deepen and lower the surrounding ice-sheet surface, leaving adjacent mountains exposed. Geomorphological evidence suggests a change in the direction of regional ice flow accompanied emergence. Simple calculations suggest that isostatic compensation caused by the deepening of bounding ice-stream troughs lowered the ice-sheet surface relative to the mountains by ~800m. Use of multiple cosmogenic isotopes on bedrock and erratics (26Al, 10Be, 21Ne) provides evidence that overriding of the massif and the deepening of the adjacent troughs occurred earlier than the Quaternary. Perhaps this occurred in the mid-Miocene, as elsewhere in East Antarctica in the McMurdo Dry Valleys and the Lambert basin. The implication is that glacial erosion instigates feedback that can change ice-sheet thickness, extent, and direction of flow. Indeed, as the subglacial troughs evolve over millions of years, they increase topographic relief; and this changes the dynamics of the ice sheet. © 2013 Elsevier B.V
Completeness of the classical 2D Ising model and universal quantum computation
We prove that the 2D Ising model is complete in the sense that the partition
function of any classical q-state spin model (on an arbitrary graph) can be
expressed as a special instance of the partition function of a 2D Ising model
with complex inhomogeneous couplings and external fields. In the case where the
original model is an Ising or Potts-type model, we find that the corresponding
2D square lattice requires only polynomially more spins w.r.t the original one,
and we give a constructive method to map such models to the 2D Ising model. For
more general models the overhead in system size may be exponential. The results
are established by connecting classical spin models with measurement-based
quantum computation and invoking the universality of the 2D cluster states.Comment: 4 pages, 1 figure. Minor change
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