algorithms

Engineering Top-Down Weight-Balanced Trees

Weight-balanced trees are a popular form of self-balancing binary search trees. Their popularity is due to desirable guarantees, for example regarding the required work to balance annotated trees. While usual weight-balanced trees perform their …

Shaving Peaks by Augmenting the Dependency Graph

Demand Side Management (DSM) is an important building block for future energy systems, since it mitigates the non-dispatchable, fluctuating power generation of renewables. For centralized DSM to be implemented on a large scale, considerable amounts …

Multilevel Planarity

In this paper, we introduce and study the multilevel-planarity testing problem, which is a generalization of upward planarity and level planarity. Let $G = (V, E)$ be a directed graph and let $\ell : V \rightarrow \mathcal P(\mathbb Z)$ be a function …

On the readability of leaders in boundary labeling

External labeling deals with annotating features in images with labels that are placed outside of the image and are connected by curves (so-called leaders) to the corresponding features. While external labeling has been extensively investigated from …

How much demand side flexibility do we need? Analyzing where to exploit flexibility in industrial processes

We introduce a novel approach to demand side management: Instead of using flexibility that needs to be defined by a domain expert, we identify a small subset of processes of e. g. an industrial plant that would yield the largest benefit if they were …

Exploiting flexibility in smart grids at scale

Large parts of the worldwide energy system are undergoing drastic changes at the moment. Two of these changes are the increasing share of intermittent generation technologies and the advent of the smart grid. A possible application of smart grids is …

A comprehensive modelling framework for demand side flexibility in smart grids

The increasing share of renewable energy generation in the electricity system comes with significant challenges, such as the volatility of renewable energy sources. To tackle those challenges, demand side management is a frequently mentioned remedy. …

Experimental Comparison of Semantic Word Clouds

We study the problem of computing semantics-preserving word clouds in which semantically related words are close to each other. We implement three earlier algorithms for creating word clouds and three new ones. We define several metrics for …