Streamline Simulation to Improve Polymer Enhanced Oil Recovery for a Mature Oil Field in Austria

Imperial Users onl

Enhancing Sustainability by Landscape-Design and Conversion to Organic Agriculture

A hilly site with variable soils and facing all the problems of modern agriculture was re-designed and converted to organic agriculture in 1992. After 10 years of measurements and observations it was determined that soil compaction, runoff, and erosion were reduced, quality of groundwater and ponds was gradually enhanced, diversity of wildlife was enriched, and the economic situation of the farmer was improved. Besides landscape design, conversion to organic agriculture is regarded as a key instrument towards sustainable land use in this region

Improved Polynomial Remainder Sequences for Ore Polynomials

Polynomial remainder sequences contain the intermediate results of the Euclidean algorithm when applied to (non-)commutative polynomials. The running time of the algorithm is dependent on the size of the coefficients of the remainders. Different ways have been studied to make these as small as possible. The subresultant sequence of two polynomials is a polynomial remainder sequence in which the size of the coefficients is optimal in the generic case, but when taking the input from applications, the coefficients are often larger than necessary. We generalize two improvements of the subresultant sequence to Ore polynomials and derive a new bound for the minimal coefficient size. Our approach also yields a new proof for the results in the commutative case, providing a new point of view on the origin of the extraneous factors of the coefficients

Measuring the quantum state of a single system with minimum state disturbance

Conventionally, unknown quantum states are characterized using quantum-state tomography based on strong or weak measurements carried out on an ensemble of identically prepared systems. By contrast, the use of protective measurements offers the possibility of determining quantum states from a series of weak, long measurements performed on a single system. Because the fidelity of a protectively measured quantum state is determined by the amount of state disturbance incurred during each protective measurement, it is crucial that the initial quantum state of the system is disturbed as little as possible. Here we show how to systematically minimize the state disturbance in the course of a protective measurement, thus enabling the maximization of the fidelity of the quantum-state measurement. Our approach is based on a careful tuning of the time dependence of the measurement interaction and is shown to be dramatically more effective in reducing the state disturbance than the previously considered strategy of weakening the measurement strength and increasing the measurement time. We describe a method for designing the measurement interaction such that the state disturbance exhibits polynomial decay to arbitrary order in the inverse measurement time $1/T$. We also show how one can achieve even faster, subexponential decay, and we find that it represents the smallest possible state disturbance in a protective measurement. In this way, our results show how to optimally measure the state of a single quantum system using protective measurements.Comment: 7 pages, 4 figures, identical to published versio

What is Usability? A Characterization based on ISO 9241-11 and ISO/IEC 25010

According to Brooke* "Usability does not exist in any absolute sense; it can only be defined with reference to particular contexts." That is, one cannot speak of usability without specifying what that particular usability is characterized by. Driven by the feedback of a reviewer at an international conference, I explore in which way one can precisely specify the kind of usability they are investigating in a given setting. Finally, I come up with a formalism that defines usability as a quintuple comprising the elements level of usability metrics, product, users, goals and context of use. Providing concrete values for these elements then constitutes the investigated type of usability. The use of this formalism is demonstrated in two case studies. * J. Brooke. SUS: A "quick and dirty" usability scale. In P. W. Jordan, B. Thomas, B. A. Weerdmeester, and A. L. McClelland, editors, Usability Evaluation in Industry. Taylor and Francis, 1996.Comment: Technical Report; Department of Computer Science, Technische Universit\"at Chemnitz; also available from https://www.tu-chemnitz.de/informatik/service/ib/2015.php.e

Regularity of Lie Groups

We solve the regularity problem for Milnor's infinite dimensional Lie groups in the $C^0$-topological context, and provide necessary and sufficient regularity conditions for the standard setting ($C^k$-topology). We prove that the evolution map is $C^0$-continuous on its domain $\textit{iff}\hspace{1pt}$ the Lie group $G$ is locally $\mu$-convex. We furthermore show that if the evolution map is defined on all smooth curves, then $G$ is Mackey complete - This is a completeness condition formulated in terms of the Lie group operations that generalizes Mackey completeness as defined for locally convex vector spaces. Then, under the presumption that $G$ is locally $\mu$-convex, we show that each $C^k$-curve, for $k\in \mathbb{N}_{\geq 1}\sqcup\{\mathrm{lip},\infty\}$, is integrable (contained in the domain of the evolution map) $\textit{iff}\hspace{1pt}$ $G$ is Mackey complete and $\mathrm{k}$-confined. The latter condition states that each $C^k$-curve in the Lie algebra $\mathfrak{g}$ of $G$ can be uniformly approximated by a special type of sequence consisting of piecewise integrable curves - A similar result is proven for the case $k\equiv 0$; and we provide several mild conditions that ensure that $G$ is $\mathrm{k}$-confined for each $k\in \mathbb{N}\sqcup\{\mathrm{lip},\infty\}$. We finally discuss the differentiation of parameter-dependent integrals in the standard topological context. In particular, we show that if the evolution map is well defined and continuous on $C^k([0,1],\mathfrak{g})$ for $k\in \mathbb{N}\sqcup\{\infty\}$, then it is smooth thereon $\textit{iff}\hspace{1pt}$ $\mathfrak{g}$ is $\hspace{0.2pt}$ Mackey complete for $k\in \mathbb{N}_{\geq 1}\sqcup\{\infty\}$ $\hspace{1pt}/\hspace{1pt}$ integral complete for $k\equiv 0$. This result is obtained by calculating the directional derivatives explicitly - recovering the standard formulas that hold in the Banach case.Comment: 72 pages. Revised version: notations simplified; oversights corrected; example added to Sect. 3.5.2; Lemma 40 (now Lemma 13) shifted into Sect. 3.5.4; Lipschitz case added to Lemma 23 (now Lemma 24); proof of Lemma 25 (now Lemma 26) revised; Proposition 6 correcte

International Migration as Absolute Natural Law: An Inquiry into International Migration from the Perspective of Legal Philosophy

This paper investigates to what extent international migration law is coherent with the concept of migration as a natural human right. Based on the assumption that migration is an inherently human behavior, beneficial to humankind, and therefore natural law, an analysis of the most prominent sources of international migration law is undertaken. The result of the analysis shows that modern international migration law is largely in line with the concept of natural law, and that the criminalization of migration happens on the domestic level, where economic and populist motivations inform policy makers and shape the law