@article{40398, author = {{Dyakonov, I V and Sharapova, Polina and Iskhakov, T Sh and Leuchs, G}}, issn = {{1612-2011}}, journal = {{Laser Physics Letters}}, keywords = {{Physics and Astronomy (miscellaneous), Instrumentation}}, number = {{6}}, publisher = {{IOP Publishing}}, title = {{{Direct Schmidt number measurement of high-gain parametric down conversion}}}, doi = {{10.1088/1612-2011/12/6/065202}}, volume = {{12}}, year = {{2015}}, } @inproceedings{55059, author = {{Salin, Vladimir and Slastihina, Maria and Ermilov, Ivan and Speck, René and Auer, Sören and Papshev, Sergey}}, booktitle = {{Knowledge Engineering and Semantic Web: 6th International Conference, KESW 2015, Moscow, Russia, September 30-October 2, 2015, Proceedings 6}}, pages = {{182–194}}, title = {{{Semantic clustering of website based on its hypertext structure}}}, year = {{2015}}, } @inbook{30999, abstract = {{Schulisches Wohlbe nden ist als Indikator von Schulqualität vor allem für inklusive Schulen bedeutsam. Als mehrdimensionales Konstrukt wurde es bereits einschlägig operationalisiert (z. B. Hascher 2004), jedoch nicht in Bezug auf den Einsatz bei Schülerinnen und Schülern mit sonderpädagogischem Förderbedarf in inklusiven Schulen der Sekundarstufe I systematisch untersucht. In einem interdisziplinären Team wurde unter Bezug auf eingeführte Instrumente ein Fragebogen entwickelt und bei einer Vollerhebung der Jahrgänge 6 bis 10 an der Laborschule Bielefeld, Versuchsschule des Landes Nordrhein-Westfalen, eingesetzt (N = 292, davon N = 26 mit sonderpädagogischem Förderbedarf). Die beste Modellanpassung im Rahmen einer kon rmatorischen Faktorenanalyse zur Prüfung der Konstruktvalidität erreicht ein Modell mit sechs korrelierten Faktoren. Der Beitrag berichtet psychometrische Kennwerte der Skalen und weitere Ergebnisse, z. B. zur konvergenten Validität.}}, author = {{Kullmann, Harry and Geist, Sabine and Lütje-Klose, Birgit}}, booktitle = {{Inklusion von Schülerinnen und Schülern mit sonderpädagogischem Förderbedarf in Schulleistungserhebungen}}, editor = {{Kuhl, Poldi and Stanat, Petra and Lütje-Klose, Birgit and Gresch, Cornelia and Anand Pant, Hans and Prenzel, Manfred}}, isbn = {{978-3-658-06604-8}}, pages = {{301–333}}, publisher = {{Springer VS}}, title = {{{Erfassung schulischen Wohlbefindens in inklusiven Schulen ‒ Befunde zur Erprobung eines mehrdimensionalen Konstrukts in fünf Jahrgängen der Sekundarstufe I an der Laborschule Bielefeld}}}, doi = {{10.1007/978-3-658-06604-8}}, year = {{2015}}, } @inproceedings{25481, author = {{Saleem, Muhammad and Ngonga Ngomo, Axel-Cyrille}}, booktitle = {{The Semantic Web: Trends and Challenges - 11th International Conference, {ESWC} 2014, Anissaras, Crete, Greece, May 25-29, 2014. Proceedings}}, editor = {{Presutti, Valentina and d'Amato, Claudia and Gandon, Fabien and d'Aquin, Mathieu and Staab, Steffen and Tordai, Anna}}, pages = {{176--191}}, publisher = {{Springer}}, title = {{{HiBISCuS: Hypergraph-Based Source Selection for SPARQL Endpoint Federation}}}, doi = {{10.1007/978-3-319-07443-6\_13}}, volume = {{8465}}, year = {{2014}}, } @inproceedings{25482, author = {{Ngonga Ngomo, Axel-Cyrille and Ahmed Sherif, Mohamed and Lyko, Klaus}}, booktitle = {{The Semantic Web: Trends and Challenges - 11th International Conference, {ESWC} 2014, Anissaras, Crete, Greece, May 25-29, 2014. Proceedings}}, editor = {{Presutti, Valentina and d'Amato, Claudia and Gandon, Fabien and d'Aquin, Mathieu and Staab, Steffen and Tordai, Anna}}, pages = {{380--394}}, publisher = {{Springer}}, title = {{{Unsupervised Link Discovery through Knowledge Base Repair}}}, doi = {{10.1007/978-3-319-07443-6\_26}}, volume = {{8465}}, year = {{2014}}, } @inproceedings{25489, author = {{Rula, Anisa and Palmonari, Matteo and Ngonga Ngomo, Axel-Cyrille and Gerber, Daniel and Lehmann, Jens and Bühmann, Lorenz}}, booktitle = {{The Semantic Web: Trends and Challenges - 11th International Conference, {ESWC} 2014, Anissaras, Crete, Greece, May 25-29, 2014. Proceedings}}, editor = {{Presutti, Valentina and d'Amato, Claudia and Gandon, Fabien and d'Aquin, Mathieu and Staab, Steffen and Tordai, Anna}}, pages = {{488--503}}, publisher = {{Springer}}, title = {{{Hybrid Acquisition of Temporal Scopes for RDF Data}}}, doi = {{10.1007/978-3-319-07443-6\_33}}, volume = {{8465}}, year = {{2014}}, } @inproceedings{25491, author = {{Khalili, Ali and Auer, Sören and Ngonga Ngomo, Axel-Cyrille}}, booktitle = {{The Semantic Web: Trends and Challenges - 11th International Conference, {ESWC} 2014, Anissaras, Crete, Greece, May 25-29, 2014. Proceedings}}, editor = {{Presutti, Valentina and d'Amato, Claudia and Gandon, Fabien and d'Aquin, Mathieu and Staab, Steffen and Tordai, Anna}}, pages = {{628--643}}, publisher = {{Springer}}, title = {{{conTEXT - Lightweight Text Analytics Using Linked Data}}}, doi = {{10.1007/978-3-319-07443-6\_42}}, volume = {{8465}}, year = {{2014}}, } @article{19575, author = {{Büker, Petra}}, journal = {{Praxis Deutsch, Sonderheft: Durch die Schuljahre 5/6}}, pages = {{96--100}}, title = {{{„Ich bin dafür, dass...“ Kinder gewinnen Standpunkte}}}, year = {{2014}}, } @inproceedings{20129, author = {{Hamann, Heiko and Sayama, Hiroki and Rieffel, John and Risi, Sebastian and Doursat, Rene and Lipson, Hod}}, booktitle = {{14th Int. Conf. on the Synthesis and Simulation of Living Systems (ALIFE 2014)}}, pages = {{344--351}}, publisher = {{MIT Press}}, title = {{{Evolution of Collective Behaviors by Minimizing Surprise}}}, doi = {{10.7551/978-0-262-32621-6-ch055}}, year = {{2014}}, } @article{26913, abstract = {{Primary school years seem to represent a critical period for the development of overweight and obesity. However, only a few studies have analysed the prospective relationship between dietary patterns and weight status in children. The aims of the present study were to identify dietary patterns at the beginning of and during the primary school period and to examine their relevance to the development of body composition. Nutritional and anthropometric data from 371 participants of the Dortmund Nutritional and Longitudinally Designed (DONALD) Study at the beginning (ages 6 and 7 years) and end (ages 10 and 11 years) of the primary school period were used. Principal component analyses (PCA) were conducted to identify dietary patterns, which were regressed on changes in BMI and fat mass index (FMI) between ages 6 and 7 years and ages 10 and 11 years. Reduced rank regression (RRR) was used to directly extract patterns explaining variation in changes in BMI and FMI between ages 6 and 7 years and ages 10 and 11 years. PCA yielded interpretable patterns of dietary changes at the beginning of and during the primary school period, which were not related to changes in body composition. Conversely, RRR allowed identifying predictive patterns: higher baseline intakes of white bread and lower baseline intakes of whole-grain products as well as increases in the consumption of savoury snacks, sausages and cheese during primary school years independently predicted increases in BMI and FMI during the primary school period. In conclusion, selection of unfavourable carbohydrate sources at the beginning of the primary school period and increases in the consumption of processed savoury foods during primary school years may adversely affect the development of body composition during the course of primary school.}}, author = {{Diethelm, Katharina and Günther, Anke L. B. and Schulze, Matthias B. and Standl, Marie and Heinrich, Joachim and Buyken, Anette}}, issn = {{0007-1145}}, journal = {{British Journal of Nutrition}}, pages = {{1488--1498}}, title = {{{Prospective relevance of dietary patterns at the beginning and during the course of primary school to the development of body composition}}}, doi = {{10.1017/s0007114513004017}}, year = {{2014}}, } @article{26917, author = {{Goletzke, Janina and Buyken, Anette and Joslowski, Gesa and Bolzenius, Katja and Remer, Thomas and Carstensen, Maren and Egert, Sarah and Nöthlings, Ute and Rathmann, Wolfgang and Roden, Michael and Herder, Christian}}, issn = {{0022-3166}}, journal = {{The Journal of Nutrition}}, pages = {{1586--1593}}, title = {{{Increased Intake of Carbohydrates from Sources with a Higher Glycemic Index and Lower Consumption of Whole Grains during Puberty Are Prospectively Associated with Higher IL-6 Concentrations in Younger Adulthood among Healthy Individuals}}}, doi = {{10.3945/jn.114.193391}}, year = {{2014}}, } @inproceedings{329, abstract = {{Network emulations are widely used for testing novel network protocols and routing algorithms in realistic scenarios. Up to now, there is no emulation tool that is able to emulate large software-defined data center networks that consist of several thousand nodes. Mininet is the most common tool to emulate Software-Defined Networks of several hundred nodes. We extend Mininet to span an emulated network over several physical machines, making it possible to emulate networks of several thousand nodes on just a handful of physical machines. This enables us to emulate, e.g., large data center networks. To test this approach, we additionally introduce a traffic generator for data center traffic. Since there are no data center traffic traces publicly available we use the results of two recent traffic studies to create synthetic traffic. We show the design and discuss some challenges we had in building our traffic generator. As a showcase for our work we emulated a data center consisting of 3200 hosts on a cluster of only 12 physical machines. We show the resulting workloads and the trade-offs involved.}}, author = {{Wette, Philip and Dräxler, Martin and Schwabe, Arne and Wallaschek, Felix and Zahraee, Mohammad Hassan and Karl, Holger}}, booktitle = {{Proceedings of the 2014 IFIP Networking Conference (Networking 2014)}}, pages = {{1--9}}, title = {{{MaxiNet: Distributed Emulation of Software-Defined Networks}}}, doi = {{10.1109/IFIPNetworking.2014.6857078}}, year = {{2014}}, } @inproceedings{339, abstract = {{Preemptive Routing and Wavelength Assignment (RWA) algorithms preempt established lightpaths in case notenough resources are available to set up a new lightpath in aWavelength Division Multiplexing (WDM) network. The selectionof lightpaths to be preempted relies on internal decisions of theRWA algorithm. Thus, if dedicated properties of the networktopology are required by the applications running on the network,these requirements have to be known to the RWA algorithm.We present a family of preemptive RWA algorithms for WDMnetworks. These algorithms have two distinguishing features: a)they can handle dynamic traffic by on-the-fly reconfiguration,and b) users can give feedback for reconfiguration decisions andthus influence the preemption decision of the RWA algorithm,leading to networks which adapt directly to application needs.This is different from traffic engineering where the network is(slowly) adapted to observed traffic patterns.Our algorithms handle various WDM network configurationsincluding networks consisting of heterogeneous WDM hardware.To this end, we are using the layered graph approach togetherwith a newly developed graph model that is used to determineconflicting lightpaths.}}, author = {{Wette, Philip and Karl, Holger}}, booktitle = {{Proceedings of the IEEE International Conference on Communications 2014}}, pages = {{3270--3276}}, title = {{{Using Application Layer Knowledge in Routing and Wavelength Assignment Algorithms}}}, doi = {{10.1109/ICC.2014.6883825}}, year = {{2014}}, } @phdthesis{343, author = {{Künsemöller, Jörn}}, publisher = {{Universität Paderborn}}, title = {{{Tragedy of the Common Cloud - Game Theory on the Infrastructure-as-a-Service Market}}}, year = {{2014}}, } @inproceedings{354, abstract = {{In distributed cloud computing, application deployment across multiple sites can improve quality of service. Recent research developed algorithms to find optimal locations for virtual machines. However, those algorithms assume to have either single-tier applications or a fixed number of virtual machines – a strong simplification of reality. This paper investigates the placement and scaling of complex application architectures. An application is dynamically scaled to fit both the current demand situation and the currently available infrastructure resources. We compare two approaches: The first one is based on virtual network embedding. The second approach is a novel method called Template Embedding. It is based on a hierarchical 1-allocation hub flow problem and combines applica- tion scaling and embedding in one step. Extensive experiments on 43200 network configurations showed that Template Embedding outperforms virtual network embedding in all cases in three metrics: success rate, solution quality, and runtime. This positive result shows that template embedding is a promising approach for distributed cloud resource allocation.}}, author = {{Keller, Matthias and Robbert, Christoph and Karl, Holger}}, booktitle = {{Proceedings of 7th International Conference on Utility and Cloud Computing (UCC)}}, pages = {{387----395}}, title = {{{Template Embedding: Using Application Architecture to Allocate Resources in Distributed Clouds}}}, doi = {{10.1109/UCC.2014.49}}, year = {{2014}}, } @inproceedings{360, abstract = {{Network appliances perform different functions on network flows and constitute an important part of an operator’s network. Normally, a set of chained network functions process network flows. Following the trend of virtualization of networks, virtualization of the network functions has also become a topic of interest. We define a model for formalizing the chaining of network functions using a context-free language. We process deployment requests and construct virtual network function graphs that can be mapped to the network. We describe the mapping as a Mixed Integer Quadratically Constrained Program (MIQCP) for finding the placement of the network functions and chaining them together considering the limited network resources and requirements of the functions. We have performed a Pareto set analysis to investigate the possible trade-offs between different optimization objectives. }}, author = {{Dräxler, Sevil and Keller, Matthias and Karl, Holger}}, booktitle = {{Proceedings of the 3rd International Conference on Cloud Networking (CloudNet)}}, pages = {{7--13}}, title = {{{Specifying and Placing Chains of Virtual Network Functions}}}, doi = {{10.1109/CloudNet.2014.6968961}}, year = {{2014}}, } @misc{361, author = {{Roeske, Daniel}}, publisher = {{Universität Paderborn}}, title = {{{Simulating load-dependent operation of picocells}}}, year = {{2014}}, } @inproceedings{372, abstract = {{In the near future many more compute resources will be available at different geographical locations. To minimize the response time of requests, application servers closer to the user can hence be used to shorten network round trip times. However, this advantage is neutralized if the used data centre is highly loaded as the processing time of re- quests is important as well. We model the request response time as the network round trip time plus the processing time at a data centre.We present a capacitated facility location problem formal- ization where the processing time is modelled as the sojourn time of a queueing model. We discuss the Pareto trade-off between the number of used data centres and the resulting response time. For example, using fewer data centres could cut expenses but results in high utilization, high response time, and smaller revenues.Previous work presented a non-linear cost function. We prove its convexity and exploit this property in two ways: First, we transform the convex model into a linear model while controlling the maximum approximation error. Sec- ond, we used a convex solver instead of a slower non-linear solver. Numerical results on network topologies exemplify our work.}}, author = {{Keller, Matthias and Karl, Holger}}, booktitle = {{Proceedings of the SIGCOMM workshop on Distributed cloud computing}}, pages = {{47----52}}, title = {{{Response Time-Optimized Distributed Cloud Resource Allocation}}}, doi = {{10.1145/2627566.2627570}}, year = {{2014}}, } @phdthesis{376, abstract = {{Radio access networks (RANs) have become one of the largest energy consumers of communication technology [LLH+13] and their energy consumption is predicted to increase [FFMB11]. To reduce the energy consumption of RANs different techniques have been proposed. One of the most promising techniques is the use of a low-power sleep mode. However, a sleep mode can also reduce the performance. In this dissertation, I quantify how much energy can be conserved with a sleep mode and which negative effects it has on the performance of RANs. Additionally, I analyze how a sleep mode can be enabled more often and how the performance can be kept high. First, I quantify the effect of power-cycle durations on energy consumption and latency in an abstract queuing system. This results in a trade-off between energy consumption and latency for a single base station (BS). Second, I show that considering a network as a whole (instead of each BS individually) allows the energy consumption to be reduced even further. After these analyses, which are not specific for RANs, I study RANs for the rest of the dissertation. RANs need to both detect and execute the requests of users. Because detection and execution of requests have different requirements, I analyze them independently. I quantify how the number of active BSs can be reduced if the detection ranges of BSs are increased by cooperative transmissions. Next, I analyze how more BSs can be deactivated if the remaining active BSs cooperate to transmit data to the users. However, in addition to increasing the range, cooperative transmissions also radiate more power. This results in higher interference for other users which slows their transmissions down and, thus, increases energy consumption. Therefore, I describe how the radiated power of cooperative transmissions can be reduced if instantaneous channel knowledge is available. Because the implementation in real hardware is impractical for demonstration purposes, I show the results of a simulation that incorporates all effects I studied analytically earlier. In conclusion, I show that a sleep mode can reduce the energy consumption of RANs if applied correctly. To apply a sleep mode correctly, it is necessary to consider power-cycle durations, power profiles, and the interaction of BSs. When this knowledge is combined the energy consumption of RANs can be reduced with only a slight loss of performance. Because this results in a trade-off between energy consumption and performance, each RAN operator has to decide which trade-off is preferred.}}, author = {{Herlich, Matthias}}, publisher = {{Universität Paderborn}}, title = {{{Reducing Energy Consumption of Radio Access Networks}}}, year = {{2014}}, } @inproceedings{382, abstract = {{This paper explores how cloud provider competition influences instance pricing in an IaaS (Infrastructure-as-a-Service) market. When reserved instance pricing includes an on-demand price component in addition to a reservation fee (two-part tariffs), different providers might offer different price combinations, where the client’s choice depends on its load profile. We investigate a duopoly of providers and analyze stable market prices in two-part tariffs. Further, we study offers that allow a specified amount of included usage (three-part tariffs). Neither two-part nor three-part tariffs produce an equilibrium market outcome other than a service pricing that equals production cost, i.e., complex price structures do not significantly affect the results from ordinary Bertrand competition.}}, author = {{Künsemöller, Jörn and Brangewitz, Sonja and Karl, Holger and Haake, Claus-Jochen}}, booktitle = {{Proceedings of the 2014 IEEE International Conference on Services Computing (SCC)}}, pages = {{203--210}}, title = {{{Provider Competition in Infrastructure-as-a-Service}}}, doi = {{10.1109/SCC.2014.35}}, year = {{2014}}, }