| 1. |
- Weinstein, John N., et al.
(författare)
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The cancer genome atlas pan-cancer analysis project
- 2013
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Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 45:10, s. 1113-1120
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Forskningsöversikt (refereegranskat)abstract
- The Cancer Genome Atlas (TCGA) Research Network has profiled and analyzed large numbers of human tumors to discover molecular aberrations at the DNA, RNA, protein and epigenetic levels. The resulting rich data provide a major opportunity to develop an integrated picture of commonalities, differences and emergent themes across tumor lineages. The Pan-Cancer initiative compares the first 12 tumor types profiled by TCGA. Analysis of the molecular aberrations and their functional roles across tumor types will teach us how to extend therapies effective in one cancer type to others with a similar genomic profile. © 2013 Nature America, Inc. All rights reserved.
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| 2. |
- Berger, Andre, et al.
(författare)
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The k–Constrained Bipartite Matching Problem: Approximation Algorithms and Applications to Wireless Networks
- 2010
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Ingår i: Proceedings IEEE INFOCOM, 2010. - : IEEE conference proceedings. - 9781424458363 ; , s. 1-9
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Konferensbidrag (refereegranskat)abstract
- In communication networks, resource assignment problems appear in several different settings. These problems are often modeled by a maximum weight matching problem in bipartite graphs and efficient matching algorithms are well known. In several applications, the corresponding matching problem has to be solved many times in a row as the underlying system operates in a time-slotted fashion and the edge weights change over time. However, changing the assignments can come with a certain cost for reconfiguration that depends on the number of changed edges between subsequent assignments. In order to control the cost of reconfiguration, we propose the k-constrained bipartite matching problem for bipartite graphs, which seeks an optimal matching that realizes at most k changes from a previous matching. We provide fast approximation algorithms with provable guarantees for this problem. Furthermore, to cope with the sequential nature of assignment problems, we introduce an online variant of the k-constrained matching problem and derive online algorithms that are based on our approximation algorithms for the k-constrained bipartite matching problem. Finally, we establish the applicability of our model and our algorithms in the context of OFDMA wireless networks finding a significant performance improvement for the proposed algorithms.
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| 3. |
- Bohge, Mathias, et al.
(författare)
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Optimal Soft Frequency Reuse and Dynamic Sub-carrier Assignments in Cellular OFDMA Networks
- 2010
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Ingår i: European transactions on telecommunications. - : Wiley. - 1124-318X .- 2161-3915. ; 21:8, s. 704-713
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Tidskriftsartikel (refereegranskat)abstract
- Soft frequency reuse (SFR) is a common technique for co-channel interference (CCI) mitigation in cellular OFDMA networks. The performance of such networks significantly depends on the configuration of the power profiles that implement the soft frequency reuse patterns. In this paper, we investigate the performance of static soft frequency reuse by comparing it against the optimal case, in which a central entity optimally distributes power among the users of the network. It is shown that there is a significant performance gap between both approaches, which needs to be filled by adaptive SFR mechanisms. Moreover, we show that the achievable gain of static SFR is small in a system that is able to optimally decide on terminal/sub-carrier assignments.
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| 4. |
- Boyd, Sally, 1949, et al.
(författare)
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Storstadsungdomars deltagande i den pågående förändringen av ä-ljudet
- 2013
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Ingår i: Svenskans beskrivning 33, 15-17 maj 2013, Helsingfors.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Forskning om språkkontakt i Skandinaviens storstäder har ofta fokuserat på språkdrag vilka upplevs som nya och framträdande (bl a. Kotsinas 1994, Ganuza 2008, Svendsen & Røyneland 2008, Quist 2008, Källström & Lindberg 2011). I denna studie undersöker vi ett mindre framträdande språkdrag som har konstaterats vara under pågående förändring i svenska, nämligen öppningen av ä-ljudet, för att se om ungdomar med utländsk bakgrund deltar på samma sätt som övriga ungdomar i denna förändring (Leinonen 2010, Gross 2012). Det kan tänkas antingen 1) att språkförändringen påskyndas av språkkontakten, 2) att ungdomarna med utländsk bakgrund inte deltar i förändringsprocessen eller 3) att det inte finns signifikanta skillnader mellan ungdomar med olika bakgrunder vad gäller denna vokal. Vår kvantitativa studie bygger på fonetiska analyser av sociolingvistiska intervjuer med 60 ungdomar från olika stadsdelar i Göteborg och Stockholm; hälften av ungdomarna har svenskfödda mödrar och hälften utlandsfödda. Första och andra formanten av tre långa referensvokaler, /ɛ:/ mättes samt /ɛ:/ i kontexten framför /r/ , normaliserades och analyserades statistiskt. Resultaten visar att den allofoniska alterneringen mellan [ɛ:] och [æ:] framför /r/ och retroflexa konsonanter kan vara på väg att försvinna, åtminstone för vissa talare. Det visar sig också att de som ”leder utvecklingen” och har det öppnaste uttalet är tjejer, ungdomar bosatta i Stockholm och ungdomar med utlandsfödda mödrar. Vår preliminära slutsats är ändå att ungdomar med utländsk bakgrund deltar på samma sätt som övriga ungdomar i förändringsprocessen, eftersom andra bakgrundsvariabler (kön och stad) verkar spela större roll i förändringen än föräldrarnas ursprungsland.
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| 5. |
- Boyd, Sally, 1949, et al.
(författare)
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Variation and Change in the Vowels of Multilingual Swedish Youth
- 2013
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Ingår i: The 9th International Symposium on Bilingualism, 10-13 June 2013, Singapore. - 9789810767587
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Variation and Change in the Vowels of Multilingual Swedish Youth Sally Boyd 1,a , Johan Gross 1,b , Therese Leinonen 2,c and James Walker 3,d 1 University of Gothenburg, Sweden 2 Society of Swedish Literature in Finland 3 York University, Toronto, Canada a sally.boyd@gu.se, b gusgrosjo@student.gu.se, c therese.leinonen@gmail.com, d jamesw@york.ca Language contact in modern urban Scandinavia is the subject of recent studies (e.g. Kotsinas, 1994, Svendsen & Røyneland, 2008, Quist, 2008, Källström & Lindberg, 2011), which tend to focus on salient majority-language linguistic features used by multilingual youth of non-Scandinavian background in contrast with monolingual Scandinavian youth. However, many such features turn out to be infrequent or show no significant difference between monolingual and multilinguals (author1 et al., in press). In this study, we focus on less salient ongoing variation and change in the Swedish vowel system (author3, author2), to determine the extent to which multilingual urban youth in Sweden participate in ongoing changes. The data for this study come from recorded sociolinguistic interviews with mul- tilingual and monolingual youth in three cities. Using interviews with 60 speakers from Stockholm and Gothenburg, half of whom have Swedish as a second language or coordinate first language, we measured a representative sample of tokens of the first and second formant values for three long vowels, though here we focus on / ä :/. After coding the tokens for a series of linguistic and social factors, we used Rbrul (Johnson, 2009) to conduct regression analyses. Preliminary results show that youth in Stockholm tend to have higher F1 values than those in Gothenburg and a possible merger between allophones of / ä :/ before /r/ and elsewhere. Differences between multilinguals and monolinguals are small but statistically significant: monolinguals tend to produce a slightly more retracted [ Ä :] (i.e. they have a lower F2) than multilinguals. Furthermore, monolinguals with more diverse social networks tend to have values that are intermediate between other monolinguals and multilinguals.These results indicate that monolingual and multilingual Swedish youth participate fully in patterns of variation and change in the contemporary vowel system, though their pattern of participation may serve to identify them with the multicultural urban setting.
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| 6. |
- Dombrowski, Christian, et al.
(författare)
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Energy-efficient multi-hop transmission for machine-to-machine communications
- 2013
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Ingår i: 2013 11th International Symposium and Workshops on Modeling and Optimization in Mobile, Ad Hoc and Wireless Networks, WiOpt 2013. - 9783901882548 ; , s. 341-348
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Konferensbidrag (refereegranskat)abstract
- Emerging machine-to-machine communication scenarios are envisioned to deal with more stringent quality-of-service demands. This relates mainly to outage and latency requirements, which are for example for safety-critical messages quite different than for traditional applications. On the other hand, it is widely accepted that machine-to-machine communication systems need to be energy-efficient because of the widespread use of battery-powered devices, but also due to their huge deployment numbers. In this paper, we address these issues with respect to multi-hop transmissions. Specifically, we deal with minimizing the consumed energy of transmitting a packet with end-to-end outage and latency requirements. We account for the cases in which the system can utilize solely average channel state information, or in addition obtain and profit from instantaneous channel state information. The developed solution is based on convex optimization. It is shown numerically that despite accounting for the energy consumption of acquiring instantaneous channel state information, especially as the outage and latency requirements become tough, it is by up to 100 times more energy efficient to convey a packet with instantaneous than with average channel state information.
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| 7. |
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| 8. |
- dos Reis, Fabio Bueno, Jr., et al.
(författare)
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Nodulation and nitrogen fixation by Mimosa spp. in the Cerrado and Caatinga biomes of Brazil
- 2010
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Ingår i: New Phytologist. - : Wiley. - 0028-646X .- 1469-8137. ; 186:4, s. 934-946
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Tidskriftsartikel (refereegranskat)abstract
- P>An extensive survey of nodulation in the legume genus Mimosa was undertaken in two major biomes in Brazil, the Cerrado and the Caatinga, in both of which there are high degrees of endemicity of the genus. Nodules were collected from 67 of the 70 Mimosa spp. found. Thirteen of the species were newly reported as nodulating. Nodules were examined by light and electron microscopy, and all except for M. gatesiae had a structure typical of effective Mimosa nodules. The endosymbiotic bacteria in nodules from all of the Mimosa spp. were identified as Burkholderia via immunolabelling with an antibody against Burkholderia phymatum STM815. Twenty of the 23 Mimosa nodules tested were shown to contain nitrogenase by immunolabelling with an antibody to the nitrogenase Fe- (nifH) protein, and using the delta 15N (15N natural abundance) technique, contributions by biological N-2 fixation of up to 60% of total plant N were calculated for Caatinga Mimosa spp. It is concluded that nodulation in Mimosa is a generic character, and that the preferred symbionts of Brazilian species are Burkholderia. This is the first study to demonstrate N-2 fixation by beta-rhizobial symbioses in the field.
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| 9. |
- Eisenblaetter, Andreas, et al.
(författare)
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A Two-Stage Approach to WLAN Planning: Detailed Performance Evaluation Along the Pareto Frontier
- 2010
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Ingår i: Proceedings of the 8th International Symposium on Modeling and Optimization in Mobile, Ad Hoc and Wireless Networks (WiOpt), 2010. - 9781424475230 ; , s. 227-236
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Konferensbidrag (refereegranskat)abstract
- This paper proposes an efficient solution to the open problem of network planning for large-scale WLAN deployments. WLAN performance is governed by the Csma-Ca protocol, whose dynamic effects are difficult to capture. Accurate performance evaluation depends on simulations and takes time. A detailed analysis of dozens candidate designs with varying Ap positions and channel assignments during network planning is therefore infeasible. In our solution, we first identify few good candidate designs using a multi-criteria optimization model, which features notions of cell overlap and station throughput. These candidate designs are taken from the corresponding Pareto frontier. In the second step, we evaluate the performance of the candidate designs by means of simulations. We apply our method to a realistic, large-scale planning scenario for an indoor office environment. The detailed simulations reveal important characteristics of the candidate designs that are not captured by the optimization model. The resulting performance differs significantly across the candidate designs. Hence, this approach successfully combines the benefits of mathematical optimization and simulations, yet avoiding their individual drawbacks.
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| 10. |
- Gross, James, 1975-, et al.
(författare)
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A Game-Theoretic Approach to Routing under Adversarial Conditions
- 2010
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Ingår i: Theoretical Computer Science. - Berlin, Heidelberg : Springer. - 9783642152405 ; , s. 355-370
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Konferensbidrag (refereegranskat)abstract
- We present a game-theoretic framework for modeling and solving routing problems in dynamically changing networks. The model covers the aspects of reactivity and non-termination, and it is motivated by quality-of-service provisioning in cognitive radio networks where data transmissions are interfered by primary systems. More precisely, we propose an infinite two-player game where a routing agent has to deliver network packets to their destinations while an adversary produces demands by generating packets and blocking connections. We obtain results on the status of basic problems, by showing principal limitations to solvability of routing requirements and singling out cases with algorithmic solutions.
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