Integrated planning of water and land-use

The role of water in spatial planning has received increasing attention in recent years. It was, for example, one of the leading motives in the preparation of the latest National Spatial Planning Note for The Netherlands. For the preparation of such spatial plans, and to support the associated policy analysis, there is a need to fully identify and characterize the interactions between the water sector and spatial planning and establish the process for making consistent joint projections for the water sector and land-use. This should account for spatial claims from the water sector, balance those claims with claims from other sectors, and feed back spatial constraints and opportunities. Land-use markets and government policies (translated e.g. in spatial reservations) form an important input in this balance. Modeling is indispensable to keep track of spatial characteristics and trace changes. Most of the available modeling considers a layered structure with a layer for national/regional projections and a GIS based layer to keep track of land use changes. Basically such model makes a distribution (rule based) of the national projections into the GIS based spatial raster, followed by an impact assessment based on the changes in the raster. Those models are generally weak in representing the processes driving land use changes such as the housing and labor market and – the water sector. The challenge remains to set up a suitable module covering these spatial - and water sector development processes. Based on the experience of the authors with many water studies and the recent development of a space-transport modeling tool (integration of transport and land-use), a sketch will be made of the requirements for such module. The scope for such planning tool will be illustrated (with data for The Netherlands), addressing key aspects such as competition for space, costs, risk, and environmental impact.

New Factorization Relations for Yang Mills Amplitudes

A double-cover extension of the scattering equation formalism of Cachazo, He and Yuan (CHY) leads us to conjecture covariant factorization formulas of n-particle scattering amplitudes in Yang-Mills theories. Evidence is given that these factorization relations are related to Berends-Giele recursions through repeated use of partial fraction identities involving linearized propagators.Comment: 7 pages, 3 figures, version to appear in PR

Monodromy and Jacobi-like Relations for Color-Ordered Amplitudes

We discuss monodromy relations between different color-ordered amplitudes in gauge theories. We show that Jacobi-like relations of Bern, Carrasco and Johansson can be introduced in a manner that is compatible with these monodromy relations. The Jacobi-like relations are not the most general set of equations that satisfy this criterion. Applications to supergravity amplitudes follow straightforwardly through the KLT-relations. We explicitly show how the tree-level relations give rise to non-trivial identities at loop level.Comment: 28 pages, 8 figures, JHEP

Unusual identities for QCD at tree-level

We discuss a set of recently discovered quadratic relations between gauge theory amplitudes. Such relations give additional structural simplifications for amplitudes in QCD. Remarkably, their origin lie in an analogous set of relations that involve also gravitons. When certain gluon helicities are flipped we obtain relations that do not involve gravitons, but which refer only to QCD.Comment: Talk given at XIV Mexican School on Particles and Fields, Morelia, Nov. 201

Impact of SDN Controllers Deployment on Network Availability

Software-defined networking (SDN) promises to improve the programmability and flexibility of networks, but it may bring also new challenges that need to be explored. The purpose of this technical report is to assess how the deployment of the SDN controllers affects the overall availability of SDN. For this, we have varied the number, homing and location of SDN controllers. A two-level modelling approach that is used to evaluate the availability of the studied scenarios. Our results show how network operators can use the approach to find the optimal cost implied by the connectivity of the SDN control platform by keeping high levels of availability.Comment: Department of Telematics, NTNU, Tech. Rep., March 201

Manifesting Color-Kinematics Duality in the Scattering Equation Formalism

We prove that the scattering equation formalism for Yang-Mills amplitudes can be used to make manifest the theory's color-kinematics duality. This is achieved through a concrete reduction algorithm which renders this duality manifest term-by-term. The reduction follows from the recently derived set of identities for amplitudes expressed in the scattering equation formalism that are analogous to monodromy relations in string theory. A byproduct of our algorithm is a generalization of the identities among gravity and Yang-Mills amplitudes.Comment: 20 pages, 20 figure

Analytic Representations of Yang-Mills Amplitudes

Scattering amplitudes in Yang-Mills theory can be represented in the formalism of Cachazo, He and Yuan (CHY) as integrals over an auxiliary projective space---fully localized on the support of the scattering equations. Because solving the scattering equations is difficult and summing over the solutions algebraically complex, a method of directly integrating the terms that appear in this representation has long been sought. We solve this important open problem by first rewriting the terms in a manifestly Mobius-invariant form and then using monodromy relations (inspired by analogy to string theory) to decompose terms into those for which combinatorial rules of integration are known. The result is a systematic procedure to obtain analytic, covariant forms of Yang-Mills tree-amplitudes for any number of external legs and in any number of dimensions. As examples, we provide compact analytic expressions for amplitudes involving up to six gluons of arbitrary helicities.Comment: 29 pages, 43 figures; also included is a Mathematica notebook with explicit formulae. v2: citations added, and several (important) typos fixe