194,769 research outputs found
Decision Support System for technology selection based on multi-criteria ranking: Application to NZEB refurbishment
Refurbishing existing building into Near Zero Energy Building (NZEB) is a key objective for the European Union. In order to achieve high rate of conversion, new refurbishment process must allow Decision Makers (DMs) (architects or designers) to sort through an ever increasing list of new technologies while taking into account uncertain preferences from multiple stakeholders. A Decision Support System (DSS) based on Multi-Criteria Decision-Making (MCDM) approaches is proposed. The DSS enables the DMs to browse the solutions space by selecting the relevant criteria, order them by preferences and specify the granularity in the assessment of the technologies regarding each criteria. This DSS is based on a ranking algorithm that operates on multiple types of quantitative (continuous, discrete, or binary) and qualitative (nominative or ordinal) variables from technological and human sources. An online user interface allows the real-time exploration of the solution space. A sensitivity analysis of the algorithm is conducted to expose the influence of the ranking algorithm parameters and to demonstrate the robustness of this algorithm. The proposed DSS is eventually implemented and validated through a use case concerning the choice of insulating materials considering heterogeneous criteria that model sustainable constraints.REfurbishment decision making platform through advanced technologies for near Zero energy BUILDing renovatio
BSP-fields: An Exact Representation of Polygonal Objects by Differentiable Scalar Fields Based on Binary Space Partitioning
The problem considered in this work is to find a dimension independent algorithm for the generation of signed scalar fields exactly representing polygonal objects and satisfying the following requirements: the defining real function takes zero value exactly at the polygonal object boundary; no extra zero-value isosurfaces should be generated; C1 continuity of the function in the entire domain. The proposed algorithms are based on the binary space partitioning (BSP) of the object by the planes passing through the polygonal faces and are independent of the object genus, the number of disjoint components, and holes in the initial polygonal mesh. Several extensions to the basic algorithm are proposed to satisfy the selected optimization criteria. The generated BSP-fields allow for applying techniques of the function-based modeling to already existing legacy objects from CAD and computer animation areas, which is illustrated by several examples
Converting between quadrilateral and standard solution sets in normal surface theory
The enumeration of normal surfaces is a crucial but very slow operation in
algorithmic 3-manifold topology. At the heart of this operation is a polytope
vertex enumeration in a high-dimensional space (standard coordinates).
Tollefson's Q-theory speeds up this operation by using a much smaller space
(quadrilateral coordinates), at the cost of a reduced solution set that might
not always be sufficient for our needs. In this paper we present algorithms for
converting between solution sets in quadrilateral and standard coordinates. As
a consequence we obtain a new algorithm for enumerating all standard vertex
normal surfaces, yielding both the speed of quadrilateral coordinates and the
wider applicability of standard coordinates. Experimentation with the software
package Regina shows this new algorithm to be extremely fast in practice,
improving speed for large cases by factors from thousands up to millions.Comment: 55 pages, 10 figures; v2: minor fixes only, plus a reformat for the
journal styl
Quadrilateral-octagon coordinates for almost normal surfaces
Normal and almost normal surfaces are essential tools for algorithmic
3-manifold topology, but to use them requires exponentially slow enumeration
algorithms in a high-dimensional vector space. The quadrilateral coordinates of
Tollefson alleviate this problem considerably for normal surfaces, by reducing
the dimension of this vector space from 7n to 3n (where n is the complexity of
the underlying triangulation). Here we develop an analogous theory for
octagonal almost normal surfaces, using quadrilateral and octagon coordinates
to reduce this dimension from 10n to 6n. As an application, we show that
quadrilateral-octagon coordinates can be used exclusively in the streamlined
3-sphere recognition algorithm of Jaco, Rubinstein and Thompson, reducing
experimental running times by factors of thousands. We also introduce joint
coordinates, a system with only 3n dimensions for octagonal almost normal
surfaces that has appealing geometric properties.Comment: 34 pages, 20 figures; v2: Simplified the proof of Theorem 4.5 using
cohomology, plus other minor changes; v3: Minor housekeepin
Pure down-conversion photons through sub-coherence length domain engineering
Photonic quantum technology relies on efficient sources of coherent single
photons, the ideal carriers of quantum information. Heralded single photons
from parametric down-conversion can approximate on-demand single photons to a
desired degree, with high spectral purities achieved through group-velocity
matching and tailored crystal nonlinearities.
Here we propose crystal nonlinearity engineering techniques with
sub-coherence-length domains. We first introduce a combination of two existing
methods: a deterministic approach with coherence-length domains and
probabilistic domain-width annealing. We then show how the same deterministic
domain-flip approach can be implemented with sub-coherence length domains. Both
of these complementary techniques create highly pure photons, outperforming
previous methods, in particular for short nonlinear crystals matched to
femtosecond lasers.Comment: 12 pages, 4 figures. Minor update to Fig.
- …