20,674 research outputs found
Leapfrogging into hydrogen technology: China's 1990-2000 energy balance
As a country beginning its motorization process, China must confront the problems attached to an oil-based car society. In adopting conventional automobile technology, the country would aggravate an already unstable oil balance while pushing up carbon dioxide levels. Not only would domestic problems emerge, but international concerns regarding oil shortage, global pollution, and the energy security balance would also result from erecting a traditional automotive infrastructure. One viable alternative the country can consider is a leapfrog towards hydrogen technology. By using hydrogen as the fuel source and investing in a hydrogen-based car society, China could overstep the problems created by an oil-based infrastructure. When examining China's potential for undertaking this technology leapfrog, China's energy past and future must be considered. China's energy balance and energy resources play a crucial role in determining the country's leapfrogging possibility. This paper analyzes one facet in China's energy balance by scrutinizing energy expenditures between 1990-2000. By looking at data compiled from major international and academic sources, an overview of China's past energy consumption and production activities is presented. Patterns and discrepancies in Chinese coal, oil, natural gas, and nuclear production are unveiled and the trends considered in relation to the country's energy balance. Each energy sector is analyzed separately for consumption and production trends. Because implementation of hydrogen technology is governed by energy resource availability and energy use patterns, such an energy analysis provides an appropriate background from which China's leapfrogging potential can be evaluated. -- Der in China beginnende Motorisierungsprozess führt zwangsläufig zu einer Konfrontation mit den Umwelt- und Ressourcenkonflikten, die mit der erdölbasierten Automobiltech-nologie des vergangenen Jahrhunderts Hand in Hand gehen. Dadurch würde sich zum einen die gegenwärtig problematische Erdölenergiebilanz des Landes durch erhöhten CO2 Ausstoß verschärfen. Zum Anderen würde der Aufbau einer chinesischen automobilen Infrastruktur auf Erdölbasis, die Ressourcenknappheit in diesem Sektor, die globalen Umweltprobleme und die Sicherung der weltweiten Energiebilanz negativ beeinflussen. Eine realistische Alternative für China ist ein Quantensprung auf dem Gebiet der Auto-mobiltechnologie zu vollziehen und in Wasserstoffmotoren zu investieren. China kann mit einer Automobilwirtschaft auf der Basis einer Wasserstofftechnologie die durch Erdöl-verbrennung geschaffenen Umweltprobleme umgehen. Dieser Artikel untersucht das Potential Chinas zu einem solchen Quantensprung in der Automobiltechnologie. Ein wesentlicher Aspekt ist die Prüfung der Energiebilanz Chinas in den Jahren 1990-2000, die es ermöglicht den Energieverbrauch und die Produktion auf Quellenbasis internationaler Organisationen und wissenschaftlicher Arbeiten, zueinander in ein Verhältnis zu setzen. Die Energiebilanz der einzelnen Sektoren Atomkraft, Kohle, Erdöl und Erdgas wird analysiert und vergleichend werden die zukünftigen Trends prognostiziert. Für die Implementation von Wasserstofftech-nologie ist die Verfügbarkeit und Nutzung von Energieressourcen von zentraler Bedeutung. Eine Analyse der Energiebilanz ist daher die Grundlage für eine wissenschaftlich fundierte Einschätzung des Potentials Chinas zu einem solchen technologischen Quantensprung.
A Robust Information Source Estimator with Sparse Observations
In this paper, we consider the problem of locating the information source
with sparse observations. We assume that a piece of information spreads in a
network following a heterogeneous susceptible-infected-recovered (SIR) model
and that a small subset of infected nodes are reported, from which we need to
find the source of the information. We adopt the sample path based estimator
developed in [1], and prove that on infinite trees, the sample path based
estimator is a Jordan infection center with respect to the set of observed
infected nodes. In other words, the sample path based estimator minimizes the
maximum distance to observed infected nodes. We further prove that the distance
between the estimator and the actual source is upper bounded by a constant
independent of the number of infected nodes with a high probability on infinite
trees. Our simulations on tree networks and real world networks show that the
sample path based estimator is closer to the actual source than several other
algorithms
Omitted variable bias of Lasso-based inference methods: A finite sample analysis
We study the finite sample behavior of Lasso-based inference methods such as
post double Lasso and debiased Lasso. We show that these methods can exhibit
substantial omitted variable biases (OVBs) due to Lasso not selecting relevant
controls. This phenomenon can occur even when the coefficients are sparse and
the sample size is large and larger than the number of controls. Therefore,
relying on the existing asymptotic inference theory can be problematic in
empirical applications. We compare the Lasso-based inference methods to modern
high-dimensional OLS-based methods and provide practical guidance
Mobilizing the Vietnamese Body: Dance Theory, Critical Refugee Studies, and the Aftermaths of War in Andrew X. Pham’s Catfish and Mandala
Mobilizing the Vietnamese Body: Dance Theory, Critical Refugee Studies, and the Aftermaths of War in Andrew X. Pham’s Catfish and Mandala
Through analysis of Andrew X. Pham’s Catfish and Mandala: A Two-Wheeled Voyage through the Landscape and Memory of Vietnam, this collaboration between a literary scholar and dance scholar joins methodologies from their respective fields to explore the politicized dimensions of the Vietnamese body-in-motion. Published in 1999, Pham\u27s memoir documents his journey, as a Vietnamese refugee living in the U.S., as he travels throughout Vietnam on a bicycle. We argue that through the literal and theoretical mobilization of his body, Catfish and Mandala constitutes a choreographic text that animates the Vietnamese body as making meaning within and beyond post-Vietnam war geopolitical formations. As such the text productively critiques the dyad of resistance and accommodation that have long structured and haunted critical inquiries into power
Higgs-- Coupling at High and Low Energy Colliders
There is no tree-level flavor changing neutral current (FCNC) in the standard
model (SM) which contains only one Higgs doublet. If more Higgs doublets are
introduced for various reasons, the tree level FCNC would be inevitable except
extra symmetry was imposed. Therefore FCNC processes are the excellent probes
for the physics beyond the SM (BSM). In this paper, we studied the lepton
flavor violated (LFV) decay processes and
induced by Higgs-- vertex. For
, its branching ratio is also related to the
, and vertices. We categorized the BSM
into two scenarios for the Higgs coupling strengths near or away from SM. For
the latter scenario, we took the spontaneously broken two Higgs doublet model
(Lee model) as an example. We considered the constraints by recent data from
LHC and B factories, and found that the measurements gave weak constraints. At
LHC Run II, will be confirmed or set stricter limit on
its branching ratio. Accordingly,
for general chosen parameters. For the positive case,
can be discovered with
pair samples at SuperB factory, Super -charm factory and new Z-factory.
The future measurements for and
will be used to distinguish these two
scenarios or set strict constraints on the correlations among different Higgs
couplings, please see Table II in the text for details.Comment: 18 pages, 10 figures, 2 table; more references added; more
discussions about cancellation in the amplitude added accoeding to the
referee's suggestion
Discussion of "EQUI-energy sampler" by Kou, Zhou and Wong
Discussion of ``EQUI-energy sampler'' by Kou, Zhou and Wong [math.ST/0507080]Comment: Published at http://dx.doi.org/10.1214/009053606000000506 in the
Annals of Statistics (http://www.imstat.org/aos/) by the Institute of
Mathematical Statistics (http://www.imstat.org
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