TY  - JOUR
A1  - Akhmatskaya, Elena
A1  - Bou-Rabee, Nawaf
A1  - Reich, Sebastian
T1  - A comparison of generalized hybrid Monte Carlo methods with and without momentum flip
N2  - The generalized hybrid Monte Carlo (GHMC) method combines Metropolis corrected constant energy simulations with a partial random refreshment step in the particle momenta. The standard detailed balance condition requires that momenta are negated upon rejection of a molecular dynamics proposal step. The implication is a trajectory reversal upon rejection, which is undesirable when interpreting GHMC as thermostated molecular dynamics. We show that a modified detailed balance condition can be used to implement GHMC without momentum flips. The same modification can be applied to the generalized shadow hybrid Monte Carlo (GSHMC) method. Numerical results indicate that GHMC/GSHMC implementations with momentum flip display a favorable behavior in terms of sampling efficiency, i.e., the traditional GHMC/GSHMC implementations with momentum flip got the advantage of a higher acceptance rate and faster decorrelation of Monte Carlo samples. The difference is more pronounced for GHMC. We also numerically investigate the behavior of the GHMC method as a Langevin-type thermostat. We find that the GHMC method without momentum flip interferes less with the underlying stochastic molecular dynamics in terms of autocorrelation functions and it to be preferred over the GHMC method with momentum flip. The same finding applies to GSHMC.
Y1  - 2009
UR  - http://www.sciencedirect.com/science/journal/00219991
U6  - https://doi.org/10.1016/j.jcp.2008.12.014
SN  - 0021-9991
ER  - 
TY  - JOUR
A1  - Samprogna Mohor, Guilherme
A1  - Hudson, Paul
A1  - Thieken, Annegret
T1  - A comparison of factors driving flood losses in households affected by different flood types
JF  - Water resources research
N2  - Flood loss data collection and modeling are not standardized, and previous work has indicated that losses from different flood types (e.g., riverine and groundwater) may follow different driving forces. However, different flood types may occur within a single flood event, which is known as a compound flood event. Therefore, we aimed to identify statistical similarities between loss-driving factors across flood types and test whether the corresponding losses should be modeled separately. In this study, we used empirical data from 4,418 respondents from four survey campaigns studying households in Germany that experienced flooding. These surveys sought to investigate several features of the impact process (hazard, socioeconomic, preparedness, and building characteristics, as well as flood type). While the level of most of these features differed across flood type subsamples (e.g., degree of preparedness), they did so in a nonregular pattern. A variable selection process indicates that besides hazard and building characteristics, information on property-level preparedness was also selected as a relevant predictor of the loss ratio. These variables represent information, which is rarely adopted in loss modeling. Models shall be refined with further data collection and other statistical methods. To save costs, data collection efforts should be steered toward the most relevant predictors to enhance data availability and increase the statistical power of results. Understanding that losses from different flood types are driven by different factors is a crucial step toward targeted data collection and model development and will finally clarify conditions that allow us to transfer loss models in space and time. <br /> Key Points <br /> Survey data of flood-affected households show different concurrent flood types, undermining the use of a single-flood-type loss model Thirteen variables addressing flood hazard, the building, and property level preparedness are significant predictors of the building loss ratio Flood type-specific models show varying significance across the predictor variables, indicating a hindrance to model transferability
KW  - Loss modeling
KW  - Riverine floods
KW  - Surface floods
KW  - Groundwater
KW  - Levee
KW  - breaches
KW  - Compound flood event
Y1  - 2020
U6  - https://doi.org/10.1029/2019WR025943
SN  - 0043-1397
SN  - 1944-7973
VL  - 56
IS  - 4
PB  - American Geophysical Union
CY  - Washington
ER  - 
TY  - JOUR
A1  - Eisert, Jens
A1  - Plenio, M. B.
T1  - A comparison of entanglement measures
N2  - We compare the entanglement of formation with a measure defined as the modulus of the negative eigenvalue of the partial transpose. In particular we investigate whether both measures give the same ordering of density perators with respect to the amount of entanglement.
Y1  - 1999
ER  - 
TY  - JOUR
A1  - Hudson, Paul
T1  - A comparison of definitions of affordability for flood risk adaption measures
BT  - a case study of current and future risk-based flood insurance premiums in Europe
JF  - Mitigation and adaptation strategies for global change : an international journal devoted to scientific, engineering, socio-economic and policy responses to environmental change
N2  - Risk-based insurance is a commonly proposed and discussed flood risk adaptation mechanism in policy debates across the world such as in the United Kingdom and the United States of America. However, both risk-based premiums and growing risk pose increasing difficulties for insurance to remain affordable. An empirical concept of affordability is required as the affordability of adaption strategies is an important concern for policymakers, yet such a concept is not often examined. Therefore, a robust metric with a commonly acceptable affordability threshold is required. A robust metric allows for a previously normative concept to be quantified in monetary terms, and in this way, the metric is rendered more suitable for integration into public policy debates. This paper investigates the degree to which risk-based flood insurance premiums are unaffordable in Europe. In addition, this paper compares the outcomes generated by three different definitions of unaffordability in order to investigate the most robust definition. In doing so, the residual income definition was found to be the least sensitive to changes in the threshold. While this paper focuses on Europe, the selected definition can be employed elsewhere in the world and across adaption measures in order to develop a common metric for indicating the potential unaffordability problem.
KW  - Flood risk
KW  - Insurance
KW  - Affordability
KW  - Climate change
KW  - Adaptation
KW  - Public policy
Y1  - 2018
U6  - https://doi.org/10.1007/s11027-017-9769-5
SN  - 1381-2386
SN  - 1573-1596
VL  - 23
IS  - 7
SP  - 1019
EP  - 1038
PB  - Springer
CY  - Dordrecht
ER  - 
TY  - JOUR
A1  - Reiche, Jürgen
A1  - Pietsch, Ullrich
A1  - Fink, Hans-Peter
A1  - Lemmetyinen, Helge
T1  - A comparison fo x-ray methods for structure refinement of Langmuir-Blodgett multilayers
N2  - The possibilities and limits of structure refinement of Langmuir-Blodgett films by means of symmetrical reflection of X- rays are described using the example of a stearic acid multilayer. Three different techniques for the determiantion of the electron density profile from reflectivity data are compared; a Fourier method, a Patterson method, and model calculations. The important role of the a priori information for finding the besft structure model is outlined.
Y1  - 1992
ER  - 
TY  - JOUR
A1  - Balci, Kubilay
A1  - Koch, Andreas
A1  - Kleinpeter, Erich
T1  - A comparative vibrational spectroscopic investigation of free mn-12S(2)O(2) and fn-12S(2)O(2) dithiacrown ethers based on DFT calculations
N2  - A successful assignment for the fundamental bands observed in the experimental IR spectra of mn-12S(2)O(2) and fn-12S(2)O(2) dithiacrown ethers was achieved by the aid of the density functional theory (DFT) based quantum mechanical calculations carried out at the 133LYP/6-31G(d) and B3LYP/6-31 + G(d) level of theory. Two different scaling approaches, '(i) scaled quantum mechanics force field (SQM FF) methodology', and (ii) the 'scaling frequencies with dual empirical scale factors', were used in order to fit the calculated harmonic frequencies to the experimental ones. Potential energy distribution (PED) calculations were carried out to define the internal coordinate contributions to each normal mode and to define the corresponding normal modes of the molecules. The effects of the conformational differences onto the IR active normal modes of the two isomeric molecules and their corresponding experimental frequencies were discussed in the light of the calculated spectral data.
Y1  - 2006
UR  - http://www.sciencedirect.com/science/journal/00222860
U6  - https://doi.org/10.1016/j.molstruc.2005.10.048
SN  - 0022-2860
ER  - 
TY  - JOUR
A1  - Spekkers, Matthieu
A1  - Roezer, Viktor
A1  - Thieken, Annegret
A1  - ten Veldhuis, Marie-Claire
A1  - Kreibich, Heidi
T1  - A comparative survey of the impacts of extreme rainfall in two international case studies
JF  - Natural hazards and earth system sciences
Y1  - 2017
U6  - https://doi.org/10.5194/nhess-17-1337-2017
SN  - 1561-8633
VL  - 17
SP  - 1337
EP  - 1355
PB  - Copernicus
CY  - Göttingen
ER  - 
TY  - JOUR
A1  - Yadavalli, Nataraja Sekhar
A1  - Loebner, Sarah
A1  - Papke, Thomas
A1  - Sava, Elena
A1  - Hurduc, Nicolae
A1  - Santer, Svetlana
T1  - A comparative study of photoinduced deformation in azobenzene containing polymer films
JF  - Soft matter
N2  - In this paper two groups supporting different views on the mechanism of light induced polymer deformation argue about the respective underlying theoretical conceptions, in order to bring this interesting debate to the attention of the scientific community. The group of Prof. Nicolae Hurduc supports the model claiming that the cyclic isomerization of azobenzenes may cause an athermal transition of the glassy azobenzene containing polymer into a fluid state, the so-called photo-fluidization concept. This concept is quite convenient for an intuitive understanding of the deformation process as an anisotropic flow of the polymer material. The group of Prof. Svetlana Santer supports the re-orientational model where the mass-transport of the polymer material accomplished during polymer deformation is stated to be generated by the light-induced re-orientation of the azobenzene side chains and as a consequence of the polymer backbone that in turn results in local mechanical stress, which is enough to irreversibly deform an azobenzene containing material even in the glassy state. For the debate we chose three polymers differing in the glass transition temperature, 32 degrees C, 87 degrees C and 95 degrees C, representing extreme cases of flexible and rigid materials. Polymer film deformation occurring during irradiation with different interference patterns is recorded using a homemade set-up combining an optical part for the generation of interference patterns and an atomic force microscope for acquiring the kinetics of film deformation. We also demonstrated the unique behaviour of azobenzene containing polymeric films to switch the topography in situ and reversibly by changing the irradiation conditions. We discuss the results of reversible deformation of three polymers induced by irradiation with intensity (IIP) and polarization (PIP) interference patterns, and the light of homogeneous intensity in terms of two approaches: the re-orientational and the photo-fluidization concepts. Both agree in that the formation of opto-mechanically induced stresses is a necessary prerequisite for the process of deformation. Using this argument, the deformation process can be characterized either as a flow or mass transport.
Y1  - 2016
U6  - https://doi.org/10.1039/c6sm00029k
SN  - 1744-683X
SN  - 1744-6848
VL  - 12
SP  - 2593
EP  - 2603
PB  - Royal Society of Chemistry
CY  - Cambridge
ER  - 
TY  - JOUR
A1  - Schaub, Torsten H.
A1  - Wang, Kewen
T1  - A comparative study of logic programs with preference
Y1  - 2001
ER  - 
TY  - JOUR
A1  - Schaub, Torsten H.
A1  - Wang, Kewen
T1  - A comparative study of logic programs with preference
Y1  - 2001
SN  - 1-558-60777-3
SN  - 1045-0823
ER  -