607,306 research outputs found
Recommended from our members
Market Structure and Energy Efficiency: The Case of New Commercial Buildings
This is a report on why commercial office buildings arenât more energy efficient. Several decades of energy efficiency programs have resulted in some gains, but overall increases in the energy efficiency of buildings have fallen far short of the 30 to 50 percent improvement that many efficiency advocates believe is possible. The purpose of this study is to consider the âwhyâ question by empirically examining the dynamics of new commercial building markets. To do so, the authors used multiple research techniques, including qualitative field observation and interview methods that allow for a more in-depth understanding of complicated market processes. Their research focused primarily on new office buildings and centered in four regional markets: Sacramento, San Francisco, Seattle, and Portland. The authors identify key dynamics of commercial office building markets, describe how change and innovation occurs in commercial development, discuss the implications for energy efficiency, and suggest next steps
What Is a Macrostate? Subjective Observations and Objective Dynamics
We consider the question of whether thermodynamic macrostates are objective
consequences of dynamics, or subjective reflections of our ignorance of a
physical system. We argue that they are both; more specifically, that the set
of macrostates forms the unique maximal partition of phase space which 1) is
consistent with our observations (a subjective fact about our ability to
observe the system) and 2) obeys a Markov process (an objective fact about the
system's dynamics). We review the ideas of computational mechanics, an
information-theoretic method for finding optimal causal models of stochastic
processes, and argue that macrostates coincide with the ``causal states'' of
computational mechanics. Defining a set of macrostates thus consists of an
inductive process where we start with a given set of observables, and then
refine our partition of phase space until we reach a set of states which
predict their own future, i.e. which are Markovian. Macrostates arrived at in
this way are provably optimal statistical predictors of the future values of
our observables.Comment: 15 pages, no figure
Verifying security protocols by knowledge analysis
This paper describes a new interactive method to analyse knowledge of participants involved in security protocols and further to verify the correctness of the protocols. The method can detect attacks and flaws involving interleaving sessions besides normal attacks. The implementation of the method in a generic theorem proving environment, namely Isabelle, makes the verification of protocols mechanical and efficient; it can verify a medium-sized security protocol in less than ten seconds. As an example, the paper finds the flaw in the Needham-Schroeder public key authentication protocol and proves the secure properties and guarantees of the protocol with Lowe's fix to show the effectiveness of this method
The Coupled Electron-Ion Monte Carlo Method
In these Lecture Notes we review the principles of the Coupled Electron-Ion
Monte Carlo methods and discuss some recent results on metallic hydrogen.Comment: 38 pages, 6 figures, Lecture notes for the International School of
Solid State Physics, 34th course: "Computer Simulation in Condensed Matter:
from Materials to Chemical Biology", 20 July-1 August 2005 Erice (Italy). To
appear in Lecture Notes in Physics (2006
Three-dimensional theory for interaction between atomic ensembles and free-space light
Atomic ensembles have shown to be a promising candidate for implementations
of quantum information processing by many recently-discovered schemes. All
these schemes are based on the interaction between optical beams and atomic
ensembles. For description of these interactions, one assumed either a
cavity-QED model or a one-dimensional light propagation model, which is still
inadequate for a full prediction and understanding of most of the current
experimental efforts which are actually taken in the three-dimensional free
space. Here, we propose a perturbative theory to describe the three-dimensional
effects in interaction between atomic ensembles and free-space light with a
level configuration important for several applications. The calculations reveal
some significant effects which are not known before from the other approaches,
such as the inherent mode-mismatching noise and the optimal mode-matching
conditions. The three-dimensional theory confirms the collective enhancement of
the signal-to-noise ratio which is believed to be one of the main advantage of
the ensemble-based quantum information processing schemes, however, it also
shows that this enhancement need to be understood in a more subtle way with an
appropriate mode matching method.Comment: 16 pages, 9 figure
- âŠ