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See detailPrecoded Cluster Hopping in Multi-Beam High Throughput Satellite Systems
Kibria, Mirza UL; Lagunas, Eva UL; Maturo, Nicola UL et al

in Proceedings-IEEE Global Communications Conference (IEEE Globecom), Hawaii, 2019 (2019)

Beam-Hopping (BH) and precoding are two trending technologies for the satellite community. While BH enables flexibility to adapt the offered capacity to the heterogeneous demand, precoding aims at ... [more ▼]

Beam-Hopping (BH) and precoding are two trending technologies for the satellite community. While BH enables flexibility to adapt the offered capacity to the heterogeneous demand, precoding aims at boosting the spectral efficiency. In this paper, we consider a high throughput satellite (HTS) system that employs BH in conjunction with precoding. In particular, we propose the concept of Cluster-Hopping (CH) that seamlessly combines the BH and precoding paradigms and utilizes their individual competencies. The cluster is defined as a set of adjacent beams that are simultaneously illuminated. In addition, we propose an efficient time-space illumination pattern design, where we determine the set of clusters that can be illuminated simultaneously at each hopping event along with the illumination duration. We model the CH time-space illumination pattern design as an integer programming problem which can be efficiently solved. Supporting results based on numerical simulations are provided which validate the effectiveness of the proposed CH concept and time-space illumination pattern design. [less ▲]

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See detailPrecoder Design for Multibeam Mobile Satellite Systems
Joroughi, Vahid UL; Shankar, Bhavani UL; Maleki, Sina UL et al

in Proceedings of IEEE Asilomar Conference on Signals, Systems and Computers (2018)

Detailed reference viewed: 79 (4 UL)
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See detailPrecoding Design and User Selection for Multibeam Satellite Channels
Gharanjik, Ahmad UL; Shankar, Bhavani UL; Arapoglou, Pantelis-Daniel UL et al

in 16th IEEE International Workshop on Signal Processing Advances in Wireless Communications, SPAWC 2015 (2015, June 28)

Precoding for the downlink of a multibeam satellite system has been recently shown, under ideal conditions, to be promising technique towards employing aggressive frequency reuse gainfully. However, time ... [more ▼]

Precoding for the downlink of a multibeam satellite system has been recently shown, under ideal conditions, to be promising technique towards employing aggressive frequency reuse gainfully. However, time varying phase uncertainties imposed by the components and the channel, combined with delayed feedback perturbs the channel state information at the transmitter (CSIT). In this paper, we consider a power constrained robust formulation of the downlink precoding problem to counter the phase uncertainties. In particular it considers imposing conditions on the average signal to interference plus noise ratio (SINR), to deal with imperfect CSIT. In addition to the robust formulation, the primacy of user selection is highlighted and a new approach exploiting the satellite system design is proposed. Performance of the derived robust precoder in conjunction with the proposed location based user selection is then evaluated and the gains are tabulated. [less ▲]

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See detailPrecoding in multibeam satellite communications: present and future challenges
Vázquez, Miguel Ángel; Pérez-Neira, Ana; Christopoulos, Dimitrios et al

in jourlib Journal (2015)

Whenever multibeam satellite systems target very aggressive frequency reuse in their coverage area, inter-beam interference becomes the major obstacle for increasing the overall system throughput. As a ... [more ▼]

Whenever multibeam satellite systems target very aggressive frequency reuse in their coverage area, inter-beam interference becomes the major obstacle for increasing the overall system throughput. As a matter of fact, users located at the beam edges suffer from a very large interference for even a moderately aggressive planning of reuse-2. Although solutions for inter-beam interference management have been investigated at the satellite terminal, it turns out that the performance improvement does not justify the increased terminal complexity and cost. In this article, we pay attention to interference mitigation techniques that take place at the transmitter (i.e. the gateway). Based on this understanding, we provide our vision on advanced precoding techniques and user clustering methods for multibeam broadband fixed satellite communications. We also discuss practical challenges to deploy precoding schemes and the support introduced in the recently published DVB-S2X standard. Future challenges for novel configurations employing precoding are also provided. [less ▲]

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See detailPrecoding in Multibeam Satellite Communications: Present and Future Challenges
Vazquez, MA; Perez-Neira, A; Christopoulos, D et al

in IEEE Wireless Communications Letters (2016), 23(6), 88-95

Detailed reference viewed: 178 (29 UL)
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See detailPrecoding, Scheduling and Link Adaptation in Mobile Interactive Multibeam Satellite Systems
Vazquez, Miguel-Angel; Shankar, Bhavani UL; Kourogiorgas, Charilaos et al

in IEEE Journal on Selected Areas In Communications (2018), 36(5), 971-980

This paper deals with the problem of precoding, scheduling and link adaptation in next generation mobile interactive multibeam satellite systems. In contrast to the fixed satellite services, when the user ... [more ▼]

This paper deals with the problem of precoding, scheduling and link adaptation in next generation mobile interactive multibeam satellite systems. In contrast to the fixed satellite services, when the user terminals move across the coverage area, additional challenges appear. Due to the time varying channel, the gateway has only access to a delayed version of the channel state information (CSI) which can eventually limit the overall system performance. However, in contrast to general multiuser multipleinput- multiple-output terrestrial systems, the CSI degradation in multibeam mobile applications has a very limited impact for typical fading channel and system assumptions. Under realistic conditions, the numerical results show that precoding can offer an attractive gain in the system throughput compared to conservative frequency reuse allocations. [less ▲]

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See detailPrecommitment in Competing Vertical Chains
Irmen, Andreas UL

in Journal of Economic Surveys (1998), 12(4), 333-59

The design of distribution channels is an important marketing decision since a revision implies costly reorganization. Hence, it makes sense to study strategic motives of alternative distribution devices ... [more ▼]

The design of distribution channels is an important marketing decision since a revision implies costly reorganization. Hence, it makes sense to study strategic motives of alternative distribution devices. A precommitment is a strategic move that affects the other players' expectations on how oneself will behave and thus induces them to choose in one's own favor (Schelling, 1960). How these tactics can be used by firms to favorably influence competition between vertical chains is the topic of the literature reviewed in this survey. Copyright 1998 by Blackwell Publishers Ltd [less ▲]

Detailed reference viewed: 91 (4 UL)
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See detailPrecursor mediated crystallization in suspensions of hard shperes
Schilling, Tanja UL; Schöpe, H. J.; Oettel, M. et al

in Physical Review Letters (2010), 105

Detailed reference viewed: 51 (1 UL)
See detailPredgovor
Glaurdic, Josip UL

in Goldberg, Jeffrey (Ed.) Obama: Vanjskopolitička doktrina (2016)

Detailed reference viewed: 91 (13 UL)
See detailPredgovor hrvatskom izdanju
Glaurdic, Josip UL

in Clinton, Bill (Ed.) Natrag na posao - Zašto trebamo pametnu državu za snažnu ekonomiju (2012)

Detailed reference viewed: 60 (1 UL)
See detailPredgovor hrvatskom izdanju
Glaurdic, Josip UL

in Nye, Joseph S. (Ed.) Budućnost moći (2012)

Detailed reference viewed: 53 (1 UL)
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See detailPredicting Air Compressor Failures with Echo State Networks
Fan, Yuantao; Nowaczyk, S. Lawomir; Rögnvaldsson, Thorsteinn et al

in Third European Conference of the Prognostics and Health Management Society 2016, Bilbao, Spain, 5-8 July, 2016 (2016)

Detailed reference viewed: 58 (1 UL)
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See detailPredicting asthma treatment outcome at diagnosis: The role of symptom perception during a histamine challenge test
Janssens, Thomas; Verleden, Geert; De Peuter, Steven et al

in Journal of Asthma (2011), 49(3), 63-69

Detailed reference viewed: 94 (0 UL)
See detailPredicting Crystal Growth - A Computer Game
Schilling, Tanja UL

Presentation (2012)

Detailed reference viewed: 27 (1 UL)
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See detailPredicting first-grade mathematics achievement: the contributions of domain-general cognitive abilities, nonverbal number sense, and early number competence
Hornung, Caroline UL; Schiltz, Christine UL; Brunner, Martin UL et al

in Frontiers in Psychology [=FPSYG] (2014), 5

Early number competence, grounded in number-specific and domain-general abilities, is supposed to lay the foundation for later math achievement. Few longitudinal studies tested a comprehensive model for ... [more ▼]

Early number competence, grounded in number-specific and domain-general abilities, is supposed to lay the foundation for later math achievement. Few longitudinal studies tested a comprehensive model for early math development. Using structural equation modeling and mediation analyses, we studied the influence of kindergarteners’ basic cognitive abilities (i.e., nonverbal number sense, working memory, fluid intelligence, and receptive vocabulary) and their early number competence (i.e., symbolic number skills) on first grade math achievement (arithmetic, shape and space, and number line estimation) assessed one year later. Latent regression models revealed that nonverbal number sense and working memory are central building blocks for developing early number competence in kindergarten and that early number competence is key for first grade math achievement. Fluid intelligence significantly predicted arithmetic and number line estimation while receptive vocabulary significantly predicted shape and space after controlling for early number competence. In sum we suggest that early math achievement draws on different constellations of number-specific and domain-general mechanisms. [less ▲]

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See detailPredicting functional effects of missense variants in voltage-gated sodium and calcium channels
Heyne, Henrike O.; Baez-Nieto, David; Iqbal, Sumaiya et al

in Science Translational Medicine (2020), 12(556), 6848

Malfunctions of voltage-gated sodium and calcium channels (encoded by SCNxA and CACNA1x family genes, respectively) have been associated with severe neurologic, psychiatric, cardiac, and other diseases ... [more ▼]

Malfunctions of voltage-gated sodium and calcium channels (encoded by SCNxA and CACNA1x family genes, respectively) have been associated with severe neurologic, psychiatric, cardiac, and other diseases. Altered channel activity is frequently grouped into gain or loss of ion channel function (GOF or LOF, respectively) that often corresponds not only to clinical disease manifestations but also to differences in drug response. Experimental studies of channel function are therefore important, but laborious and usually focus only on a few variants at a time. On the basis of known gene-disease mechanisms of 19 different diseases, we inferred LOF (n = 518) and GOF (n = 309) likely pathogenic variants from the disease phenotypes of variant carriers. By training a machine learning model on sequence- and structure-based features, we predicted LOF or GOF effects [area under the receiver operating characteristics curve (ROC) = 0.85] of likely pathogenic missense variants. Our LOF versus GOF prediction corresponded to molecular LOF versus GOF effects for 87 functionally tested variants in SCN1/2/8A and CACNA1I (ROC = 0.73) and was validated in exome-wide data from 21,703 cases and 128,957 controls. We showed respective regional clustering of inferred LOF and GOF nucleotide variants across the alignment of the entire gene family, suggesting shared pathomechanisms in the SCNxA/CACNA1x family genes. [less ▲]

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See detailPredicting Functional Effects of Missense Variants in Voltage-Gated Sodium and Calcium Channels
Heyne, Henrike O.; Baez-Nieto, David; Iqbal, Sumaiya et al

E-print/Working paper (2019)

Malfunctions of voltage-gated sodium and calcium channels (SCN and CACNA1 genes) have been associated with severe neurologic, psychiatric, cardiac and other diseases. Altered channel activity is ... [more ▼]

Malfunctions of voltage-gated sodium and calcium channels (SCN and CACNA1 genes) have been associated with severe neurologic, psychiatric, cardiac and other diseases. Altered channel activity is frequently grouped into gain or loss of ion channel function (GOF or LOF, respectively) which is not only corresponding to clinical disease manifestations, but also to differences in drug response. Experimental studies of channel function are therefore important, but laborious and usually focus only on a few variants at a time. Based on known gene-disease-mechanisms, we here infer LOF (518 variants) and GOF (309 variants) of likely pathogenic variants from disease phenotypes of variant carriers. We show regional clustering of inferred GOF and LOF variants, respectively, across the alignment of the entire gene family, suggesting shared pathomechanisms in the SCN/CACNA1 genes. By training a machine learning model on sequence- and structure-based features we predict LOF- or GOF- associated disease phenotypes (ROC = 0.85) of likely pathogenic missense variants. We then successfully validate the GOF versus LOF prediction on 87 functionally tested variants in SCN1/2/8A and CACNA1I (ROC = 0.73) and in exome-wide data from > 100.000 cases and controls. Ultimately, functional prediction of missense variants in clinically relevant genes will facilitate precision medicine in clinical practice. [less ▲]

Detailed reference viewed: 164 (0 UL)