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71.
Sauli Ruuska Kaisa Miettinen Margaret M. Wiecek 《Journal of Optimization Theory and Applications》2012,153(1):60-74
The relationship between bilevel optimization and multiobjective optimization has been studied by several authors, and there have been repeated attempts to establish a link between the two. We unify the results from the literature and generalize them for bilevel multiobjective optimization. We formulate sufficient conditions for an arbitrary binary relation to guarantee equality between the efficient set produced by the relation and the set of optimal solutions to a bilevel problem. In addition, we present specially structured bilevel multiobjective optimization problems motivated by real-life applications and an accompanying binary relation permitting their reduction to single-level multiobjective optimization problems. 相似文献
72.
The notion of coexistence of quantum observables was introduced to describe the possibility of measuring two or more observables together. Here we survey the various different formalisations of this notion and their connections. We review examples illustrating the necessary degrees of unsharpness for two noncommuting observables to be jointly measurable (in one sense of the phrase). We demonstrate the possibility of measuring together (in another sense of the phrase) noncoexistent observables. This leads us to a reconsideration of the connection between joint measurability and noncommutativity of observables and of the statistical and individual aspects of quantum measurements. 相似文献
73.
We investigate a novel concept to efficiently generate multiphoton induced fluorescence from organic molecules. The concept is based on frustrating the energy transfer between a fluorescent donor and one or more acceptors in conjugated molecules. The nonlinearity is not based on higher order molecular susceptibilities but entirely on their linear properties. Therefore, in contrast to nonresonant multiphoton absorption, this method does not require high local intensities. Likewise, the production of visible fluorescence does not require an infrared excitation wavelength. Hence, when applied to scanning microscopy this property is predicted to increase spatial resolution. Instead of the ∼10 GW/cm2 required in non-resonant multiphoton excitation, focal intensities ∼10 MW/cm2 are expected to produce an equally strong nonlinear signal. The predicted resolution is up to 30% greater than that of an ideal confocal microscope operating at the same fluorescence wavelength. The resolution improvement over non-resonant two-photon absorption microscopes is about two-fold in all directions. 相似文献
74.
Mikko Voutilainen Paul Sardini Marja Siitari-Kauppi Pekka Kek?l?inen Vesa Aho Markko Myllys Jussi Timonen 《Transport in Porous Media》2013,96(2):319-336
Numerical time-domain-diffusion simulations were used for studying the diffusion behavior of tracer molecules in rock matrix with homogeneous and heterogeneous porosity. As the heterogeneous sample in these simulations, a 3D tomographic image of altered tonalite was used, in which the mineral components and the pores resolved by X-ray microtomography were represented by their respective intragranular porosities determined previously by the 14C-PMMA method. The apparent diffusion coefficient of a tracer in altered tonalite was determined experimentally, and was then used in the simulations. In the altered tonalite analyzed, inclusion of heterogeneity in the porosity increased the diffusion coefficient by 16 %. Altered and pristine feldspar was the main mineral component in the sample (72 %), and it also provided the dominant contribution to tracer diffusion, explaining alone 52 % of the diffusion coefficient. The large pores resolved by microtomography (6 %) and altered and pristine mica (22 %) gave an equal contribution to the diffusion coefficient. The simulation method applied was also validated by comparing the results to both an analytical and a numerical solution to the diffusion equation in a homogenous medium. In addition, the method was compared to discrete-time random-walk simulations in the case of randomly placed overlapping spheres. 相似文献
75.
Let be a domain. Suppose that f ∈ W1,1loc(Ω,R2) is a homeomorphism such that Df(x) vanishes almost everywhere in the zero set of Jf. We show that f-1 ∈ W1,1loc(f(Ω),R2) and that Df−1(y) vanishes almost everywhere in the zero set of Sharp conditions to quarantee that f−1 ∈ W1,q(f(Ω),R2) for some 1<q≤2 are also given. 相似文献
76.
Pekka Kekäläinen Mikko Voutilainen Antti Poteri Pirkko Hölttä Aimo Hautojärvi Jussi Timonen 《Transport in Porous Media》2011,87(1):125-149
A model transport system is considered in which a pulse of tracer molecules is advected along a flow channel with porous walls.
The advected tracer thus undergoes diffusion, matrix-diffusion, inside the walls, which affects the breakthrough curve of
the tracer. Analytical solutions in the form of series expansions are derived for a number of situations which include a finite
depth of the porous matrix, varying aperture of the flow channel, and longitudinal diffusion and Taylor dispersion of the
tracer in the flow channel. Novel expansions for the Laplace transforms of the concentration in the channel facilitated closed-form
expressions for the solutions. A rigorous result is also derived for the asymptotic form of the breakthrough curve for a finite
depth of the porous matrix, which is very different from that for an infinite matrix. A specific experimental system was created
for validation of matrix-diffusion modeling for a matrix of finite depth. A previously reported fracture-column experiment
was also modeled. In both cases model solutions gave excellent fits to the measured breakthrough curves with very consistent
values for the diffusion coefficients used as the fitting parameters. The matrix-diffusion modeling performed could thereby
be validated. 相似文献
77.
The use of a TDI camera is restricted to cases of viewing from the direction of the surface normal. Our previous work indicated that a TDI camera can be used with viewing angles up to 30° from the surface normal which extends the usability of TDI for visual inspection applications. The objective of this paper is to examine the use of a TDI camera at a non-zero viewing angle under vibration conditions. The effects caused by vibration of the surface to be viewed become critical when using a TDI camera at non-zero viewing angles. A method of approximating the TDI performance under vibration conditions was determined and evaluated experimentally. The resulting measurements support the approximating method developed here. 相似文献
78.
Pekka Tiikkainen Antti Poso Olli Kallioniemi 《Journal of computer-aided molecular design》2009,23(4):227-239
In this work, we calculated the pair wise chemical similarity for a subset of small molecules screened against the NCI60 cancer
cell line panel. Four different compound similarity calculation methods were used: Brutus, GRIND, Daylight and UNITY. The
chemical similarity scores of each method were related to the biological similarity data set. The same was done also for combinations
of methods. In the end, we had an estimate of biological similarity for a given chemical similarity score or combinations
thereof. The data from above was used to identify chemical similarity ranges where combining two or more methods (data fusion)
led to synergy. The results were also applied in ligand-based virtual screening using the DUD data set. In respect to their
ability to enrich biologically similar compound pairs, the ranking of the four methods in descending performance is UNITY,
Daylight, Brutus and GRIND. Combining methods resulted always in positive synergy within a restricted range of chemical similarity
scores. We observed no negative synergy. We also noted that combining three or four methods had only limited added advantage
compared to combining just two. In the virtual screening, using the estimated biological similarity for ranking compounds
produced more consistent results than using the methods in isolation. 相似文献
79.
80.
Prof. Pekka Pyykkö Dr. Wen‐Hua Xu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(26):9468-9473
It has recently been suggested that the oxidation states of Ir run from the putative ?III in the synthesized solid Na3[Ir(CO)3] to the well‐documented +IX in the species IrO4+. Furthermore, [Ir(CO)3]3? was identified as an 18‐electron species. A closer DFT study now finds support for this picture: The orbitals spanned by the 6s,6p,5d orbitals of the iridium are all occupied. Although some have considerable ligand character, the deviations from 18 e leave the orbital symmetries unchanged. The isoelectronic systems from Os?IV to Au?I behave similarly, suggesting further possible species. To paraphrase Richard P. Feynmann “there is plenty of room at the bottom”. 相似文献