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See detailIs Big Data Sufficient for a Reliable Detection of Non-Technical Losses?
Glauner, Patrick UL; Migliosi, Angelo UL; Meira, Jorge Augusto UL et al

in Proceedings of the 19th International Conference on Intelligent System Applications to Power Systems (ISAP 2017) (2017, September)

Non-technical losses (NTL) occur during the distribution of electricity in power grids and include, but are not limited to, electricity theft and faulty meters. In emerging countries, they may range up to ... [more ▼]

Non-technical losses (NTL) occur during the distribution of electricity in power grids and include, but are not limited to, electricity theft and faulty meters. In emerging countries, they may range up to 40% of the total electricity distributed. In order to detect NTLs, machine learning methods are used that learn irregular consumption patterns from customer data and inspection results. The Big Data paradigm followed in modern machine learning reflects the desire of deriving better conclusions from simply analyzing more data, without the necessity of looking at theory and models. However, the sample of inspected customers may be biased, i.e. it does not represent the population of all customers. As a consequence, machine learning models trained on these inspection results are biased as well and therefore lead to unreliable predictions of whether customers cause NTL or not. In machine learning, this issue is called covariate shift and has not been addressed in the literature on NTL detection yet. In this work, we present a novel framework for quantifying and visualizing covariate shift. We apply it to a commercial data set from Brazil that consists of 3.6M customers and 820K inspection results. We show that some features have a stronger covariate shift than others, making predictions less reliable. In particular, previous inspections were focused on certain neighborhoods or customer classes and that they were not sufficiently spread among the population of customers. This framework is about to be deployed in a commercial product for NTL detection. [less ▲]

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See detailWhat do we need to say about a design method?
Gericke, Kilian UL; Eckert, Claudia; Stacey, Martin

in Proceedings of the 21st International Conference on Engineering Design (2017, August)

Method development is one of the raisons d’etre of engineering design research and method uptake by industry is perceived as an important success criterion. This paper argues that one of the problems with ... [more ▼]

Method development is one of the raisons d’etre of engineering design research and method uptake by industry is perceived as an important success criterion. This paper argues that one of the problems with methods is the lack of clarity about what is actually proposed to industry and the academic community when a new method is put forward, in terms of how detailed, strict, precise and rigorous the method is and what it can deliver. This paper puts the concept of method in the context of related concepts and proposes a multi-level model of the elements of a method to argue that a contribution on each of these levels can be of value and that the introduction of methods can fail on each of these levels. Implications thereof for industry and academia are discussed, concluding that a clear description of methods and their intended use is important for enabling proper validation of each of the method’s elements and for communicating methods to academia and industry. [less ▲]

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See detailDiscussant
Greiff, Samuel UL

Scientific Conference (2017, August)

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See detailAn engineering approach to mapping meanings in products and services
Waltersdorfer, Gregor UL; Gericke, Kilian UL; Desmet, Pieter M. A. et al

Scientific Conference (2017, August)

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See detailPolynésie et Mélanésie
Ehrhart, Sabine UL

in Reutner, Ursula (Ed.) Manuel des francophonies (2017)

Dans le présent article nous tenterons de dresser le portrait des situations d’utilisation du français dans l’océan Pacifique, dans une approche écologique, dynamique et holistique. Nous présenterons ... [more ▼]

Dans le présent article nous tenterons de dresser le portrait des situations d’utilisation du français dans l’océan Pacifique, dans une approche écologique, dynamique et holistique. Nous présenterons brièvement l’évolution historique et politique de chaque aire francophone, de son degré de francophonie et des liens qui existent entre le français et les autres langues parlées à chaque endroit, selon les domaines et fonctions d’utilisation. Certaines parties de cette vaste région se caractérisent par le tissage d’un réseau actif de relations interinsulaires. La Polynésie en est l’illustration type, alors qu’en revanche les espaces insulaires de la Mélanésie ont davantage tendance à être repliés sur eux-mêmes. [less ▲]

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See detaileXtended Variational Quasicontinuum Methodology for Modelling of Crack Propagation in Discrete Lattice Systems
Rokos, Ondrej; Peerlings, Ron; Zeman, Jan et al

Scientific Conference (2017, July 17)

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See detailAn equation-free multiscale method: a result of extending the quasicontinuum method to irregular structures
Beex, Lars UL; Kerfriden, Pierre

Scientific Conference (2017, July 16)

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See detailLa réforme du droit luxembourgeois des sociétés (2016)
Corbisier, Isabelle UL

in Revue Pratique des Sociétés - Tijdschrift voor Rechtspersoon en Vennootschap (2017), (4),

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See detailSpatial PAPR Reduction in Symbol-level Precoding for the Multi-beam Satellite Downlink
Spano, Danilo UL; Alodeh, Maha UL; Chatzinotas, Symeon UL et al

in IEEE SPAWC 2017 (2017, July)

In this work, a novel symbol-level precoding scheme is proposed, for managing the multi-user interference in the forward downlink channel of a multi-beam satellite system. Besides exploiting the ... [more ▼]

In this work, a novel symbol-level precoding scheme is proposed, for managing the multi-user interference in the forward downlink channel of a multi-beam satellite system. Besides exploiting the constructive interference effect, the proposed scheme aims at improving the robustness of the transmitted signals to the non-linear distortions of practical satellite systems. This is done by reducing the imbalances between the instantaneous power transmitted by the multiple antennas, which are detrimental in non-linear systems. More specifically, this work proposes a symbol-level precoding scheme performing the minimization of the spatial peak-to-average power ratio, under Quality-of-Service constraints. An iterative algorithm is proposed to solve the related optimization problem. Numerical results are presented to assess the performance of the proposed scheme, which outperforms the state of the art symbol-level precoding techniques in terms of spatial peak-to-average power ratio across the transmitting antennas. [less ▲]

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See detailPower Allocation for In-Band Full-Duplex Self-Backhauling
Lagunas, Eva UL; Lei, Lei UL; Maleki, Sina UL et al

in International Conference on Telecommunications and Signal Processing (TSP), Barcelona, Spain, July 2017 (2017, July)

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See detailProfiles of students on account of complex problem solving strategies
Gnaldi, M.; Bacci, S.; Greiff, Samuel UL et al

Scientific Conference (2017, July)

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See detailTo use or not to use? Investigating the validity argument for the use of short scales in research settings
Kemper, Christoph UL; Becker, N.; Baudson, T. G. et al

Scientific Conference (2017, July)

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See detailMeasuring urban forms from inter-building distances: Combining MST graphs with a Local Index of Spatial Association
Caruso, Geoffrey UL; Hilal, Mohamed; Thomas, Isabelle

in Landscape & Urban Planning (2017), 163

A new method is proposed for characterising local urban patterns at the scale of a large urban region. The approach overcomes the difficulties of surface-based representations of built-up morphologies and ... [more ▼]

A new method is proposed for characterising local urban patterns at the scale of a large urban region. The approach overcomes the difficulties of surface-based representations of built-up morphologies and provides an efficient way to account for the proximity of built and non-built land. The strength of the approach resides in the direct use of the coordinates of each building, a very parsimonious input of external parameters, and a local spatial statistical perspective. The method consists in, first, constructing and clumping the Minimum Spanning Tree (MST) that links each building to its neighbours in order to obtain connected urban and suburban graph subsets, and second, measuring a Local Index of Spatial Association (LISA) on inter-building distances in order to characterise patterns. The method differentiates heterogeneous settlements from statistically significant homogeneous clusters with either long or short connections between buildings. The method is applied to the Southern periphery of Brussels (Belgium). [less ▲]

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See detailEnergy-Efficient Design for Edge-caching Wireless Networks: When is Coded-caching beneficial?
Vu, Thang Xuan UL; Chatzinotas, Symeon UL; Ottersten, Björn UL

in Abstract book of 2017 IEEE 18th International Workshop on Signal Processing Advances in Wireless Communications (SPAWC) (2017, July)

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See detailThe interference of pain with task performance: Increasing ecological validity in research
van Ryckeghem, Dimitri UL

in Scandinavian Journal of Pain (2017), 16

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See detailProceedings of International Conference on Software and Systems Process (ICSSP)
Kuhrmann, Marco; Diebold, Philipp; Münch, Jürgen et al

in Hybrid software and system development in practice: Waterfall, scrum, and beyond (2017, July)

Software and system development faces numerous challenges of rapidly changing markets. To address such challenges, companies and projects design and adopt specific development approaches by combining well ... [more ▼]

Software and system development faces numerous challenges of rapidly changing markets. To address such challenges, companies and projects design and adopt specific development approaches by combining well-structured comprehensive methods and flexible agile practices. Yet, the number of methods and practices is large, and available studies argue that the actual process composition is carried out in a fairly ad-hoc manner. The present paper reports on a survey on hybrid software development approaches. We study which approaches are used in practice, how different approaches are combined, and what contextual factors influence the use and combination of hybrid software development approaches. Our results from 69 study participants show a variety of development approaches used and combined in practice. We show that most combinations follow a pattern in which a traditional process model serves as framework in which several fine-grained (agile) practices are plugged in. We further show that hybrid software development approaches are independent from the company size and external triggers. We conclude that such approaches are the results of a natural process evolution, which is mainly driven by experience, learning, and pragmatism. [less ▲]

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