Wat droen d’Schoulen zur Leeschtung vu Schülerinnen a Schüler bäi? E systemateschen Iwwerbléck iwwer déi aktuell Fuerschungslag an Uwennung u lëtzebuergesche Längsschnëtt-Donnéeën

Scientific Conference (2018, November 08)

Watch out for This Commit! A Study of Influential Software Changes

in Journal of Software: Evolution and Process (2019)

One single code change can significantly influence a wide range of software systems and their users. For example, 1) adding a new feature can spread defects in several modules, while 2) changing an API ... [more ▼]

One single code change can significantly influence a wide range of software systems and their users. For example, 1) adding a new feature can spread defects in several modules, while 2) changing an API method can improve the performance of all client programs. Developers often may not clearly know whether their or others’ changes are influential at commit time. Rather, it turns out to be influential after affecting many aspects of a system later. This paper investigates influential software changes and proposes an approach to identify them early, i.e., immediately when they are applied. We first conduct a post- mortem analysis to discover existing influential changes by using intuitions such as isolated changes and changes referred by other changes in 10 open source projects. Then we re-categorize all identified changes through an open-card sorting process. Subsequently, we conduct a survey with 89 developers to confirm our influential change categories. Finally, from our ground truth we extract features, including metrics such as the complexity of changes, terms in commit logs and file centrality in co-change graphs, to build ma- chine learning classifiers. The experiment results show that our prediction model achieves overall with random samples 86.8% precision, 74% recall and 80.4% F-measure respectively. [less ▲]

Water and Sea in Word and Image / L’Eau et la mer dans les textes et les images

Book published by Brill (2023)

Water Chemistry and Hydrometeorology in a Glacierized Catchment in the Polar Urals, Russia

in Journal of Mountain Science (2014), 11(5), 1097-1111

This study aims to determine the relationships between local meteorological conditions, proglacial river discharge and biogeochemical processes operating in a periglacial basin located in the Polar Ural ... [more ▼]

This study aims to determine the relationships between local meteorological conditions, proglacial river discharge and biogeochemical processes operating in a periglacial basin located in the Polar Ural mountain range, Russia. Fieldwork was conducted in the catchment of Obruchev Glacier (13 km2) during the summer peak flow period in 2008. River discharge was dominated by snowmelt and changed from 3300 l s-1 to less than 1000 l s-1. The mean daily air temperatures of stations situated in the mountain tundra and near Obruchev Glacier from July 11th to August 1st 2008 were 14.4°C and 10.3°C, respectively. The glacial river had low total dissolved solids varying from 4.5 to 9 mg l-1 and coefficients of correlation between Na+ and Cl-, K+ and Cl-, as well as NH4+ and Cl- were 0.94, 0.90 and 0.84, respectively. Rainfall events affected the snowmelt initiation and provided an essential part of the discharge during the intense snowmelt period, which occurred from July 11th to July 18th 2008. Data showed that Na+ and K+ in the surface water derived from snowmelt rather than chemical weathering of silicates. Also, it was obtained that NO3- derived from the melting snowpack, whereas ammonification occurring under the snowpacks was the primary source for NH4+. [less ▲]

Water Scarcity in California: The Effect of Internal Migration on Environmental Sustainability

Presentation (2016, May)

Water Security in Cross-Border Regions: What Relevance for Federal Human Security Regimes?

in Garrick, Dustin; Anderson, George; Connell, Daniel (Eds.) et al Federal Rivers: Managing Water in Multi-layered Political Systems (2014)

Wave propagation in networks: a system theoretic approach

in Proceedings of the 18th World Congress of the IFAC (2011)

Waveform Design for Joint Radar-Communications with Low Complexity Analog Components

Poster (2022, March)

In this paper, we aim to design an efficient and low hardware complexity based dual-function multiple-input multiple-output (MIMO) joint radar-communication (JRC) system. It is implemented via a low ... [more ▼]

In this paper, we aim to design an efficient and low hardware complexity based dual-function multiple-input multiple-output (MIMO) joint radar-communication (JRC) system. It is implemented via a low complexity analog architecture, constituted by a phase shifting network and variable gain amplifier. The proposed system exploits the multiple antenna transmitter for the simultaneous communication with multiple downlink users and radar target detection. The transmit waveform of the proposed JRC system is designed to minimize the downlink multi-user interference such that the desired radar beampattern is achieved and the architecture specific constraints are satisfied. The resulting optimization problem is non-convex and in general difficult to solve. We propose an efficient algorithmic solution based on the primal-dual framework. The numerical results show the effectiveness of the proposed approach. [less ▲]

Wavelet methods to study the pointwise regularity of the generalized Rosenblatt process

in Electronic Journal of Probability (2022), 27

We identify three types of pointwise behaviour in the regularity of the (generalized) Rosenblatt process. This extends to a non Gaussian setting previous results known for the (fractional) Brownian motion ... [more ▼]

We identify three types of pointwise behaviour in the regularity of the (generalized) Rosenblatt process. This extends to a non Gaussian setting previous results known for the (fractional) Brownian motion. On this purpose, fine bounds on the increments of the Rosenblatt process are needed. Our analysis is essentially based on various wavelet methods. [less ▲]

Wavelike charge density fluctuations and van der Waals interactions at the nanoscale

in Science (2016), 351(6278), 1171-1176

Recent experiments on noncovalent interactions at the nanoscale have challenged the basic assumptions of commonly used particle- or fragment-based models for describing van der Waals (vdW) or dispersion ... [more ▼]

Recent experiments on noncovalent interactions at the nanoscale have challenged the basic assumptions of commonly used particle- or fragment-based models for describing van der Waals (vdW) or dispersion forces. We demonstrate that a qualitatively correct description of the vdW interactions between polarizable nanostructures over a wide range of finite distances can only be attained by accounting for the wavelike nature of charge density fluctuations. By considering a diverse set of materials and biological systems with markedly different dimensionalities, topologies, and polarizabilities, we find a visible enhancement in the nonlocality of the charge density response in the range of 10 to 20 nanometers. These collective wavelike fluctuations are responsible for the emergence of nontrivial modifications of the power laws that govern noncovalent interactions at the nanoscale. [less ▲]