SwePub
Sök i SwePub databas

  Utökad sökning

Träfflista för sökning "WFRF:(Anderson John) ;hsvcat:2"

Sökning: WFRF:(Anderson John) > Teknik

  • Resultat 1-10 av 91
Sortera/gruppera träfflistan
   
NumreringReferensOmslagsbildHitta
1.
  • Komatsu, Kimberly J., et al. (författare)
  • Global change effects on plant communities are magnified by time and the number of global change factors imposed
  • 2019
  • Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 116:36, s. 17867-17873
  • Tidskriftsartikel (refereegranskat)abstract
    • Accurate prediction of community responses to global change drivers (GCDs) is critical given the effects of biodiversity on ecosystem services. There is consensus that human activities are driving species extinctions at the global scale, but debate remains over whether GCDs are systematically altering local communities worldwide. Across 105 experiments that included over 400 experimental manipulations, we found evidence for a lagged response of herbaceous plant communities to GCDs caused by shifts in the identities and relative abundances of species, often without a corresponding difference in species richness. These results provide evidence that community responses are pervasive across a wide variety of GCDs on long-term temporal scales and that these responses increase in strength when multiple GCDs are simultaneously imposed.Global change drivers (GCDs) are expected to alter community structure and consequently, the services that ecosystems provide. Yet, few experimental investigations have examined effects of GCDs on plant community structure across multiple ecosystem types, and those that do exist present conflicting patterns. In an unprecedented global synthesis of over 100 experiments that manipulated factors linked to GCDs, we show that herbaceous plant community responses depend on experimental manipulation length and number of factors manipulated. We found that plant communities are fairly resistant to experimentally manipulated GCDs in the short term (<10 y). In contrast, long-term (≥10 y) experiments show increasing community divergence of treatments from control conditions. Surprisingly, these community responses occurred with similar frequency across the GCD types manipulated in our database. However, community responses were more common when 3 or more GCDs were simultaneously manipulated, suggesting the emergence of additive or synergistic effects of multiple drivers, particularly over long time periods. In half of the cases, GCD manipulations caused a difference in community composition without a corresponding species richness difference, indicating that species reordering or replacement is an important mechanism of community responses to GCDs and should be given greater consideration when examining consequences of GCDs for the biodiversity–ecosystem function relationship. Human activities are currently driving unparalleled global changes worldwide. Our analyses provide the most comprehensive evidence to date that these human activities may have widespread impacts on plant community composition globally, which will increase in frequency over time and be greater in areas where communities face multiple GCDs simultaneously.
  •  
2.
  •  
3.
  • Anderson, John B, et al. (författare)
  • An optimal circular Viterbi decoder for the bounded distance criterion
  • 2002
  • Ingår i: IEEE Transactions on Communications. - 0090-6778. ; 50:11, s. 1736-1742
  • Tidskriftsartikel (refereegranskat)abstract
    • We propose a Viterbi-type decoder for tailbiting trellis codes that works by traversing the tailbiting circle somewhat more than once. The traversal is the least possible for any bounded distance Viterbi decoder. Procedures are given that compute this minimum. Unlike previous decoders of the type, the new scheme does not suffer limit cycles or from pseudocodewords. The bit-error rate is compared to that of Bahl-Cocke-Jelinek-Raviv and maximum-likelihood decoding.
  •  
4.
  • Anderson, John B, et al. (författare)
  • Analysis of Best High Rate Convolutional Codes for Faster than Nyquist Turbo Equalization
  • 2014
  • Ingår i: 2014 IEEE International Symposium on Information Theory (ISIT). ; , s. 1987-1991
  • Konferensbidrag (refereegranskat)abstract
    • We find good rate 2/3 and 3/4 convolutional codes for use with iterative decoding (turbo equalization) of coded intersymbol interference with AWGN. The method is based on the input-output bit error rate characteristic of the convolutional BCJR decoder module. An analysis leads to an equivalent minimum distance under the required intrinsic subtraction, which depends on free distance and an input-output LLR correlation parameter.
  •  
5.
  • Anderson, John B, et al. (författare)
  • Best Rate 1/2 Convolutional Codes for Turbo Equalization with Severe ISI
  • 2012
  • Ingår i: 2012 IEEE International Symposium on Information Theory Proceedings (ISIT). - 9781467325806 ; , s. 2366-2370
  • Konferensbidrag (refereegranskat)abstract
    • We give a procedure to find good convolutional codes for use with iterative decoding (turbo equalization) of the coded AWGN intersymbol interference (ISI) channel. The method is based on the input-output bit error rate characteristic of the convolutional BCJR module in the iterative decoder, in combination with the code minimum distance. Both are essential to find best codes. Best feedforward and recursive systematic codes are listed for memories 2-4, and some individual good codes at memory 5. Codes are tested over a root raised-cosine faster than Nyquist channel with severe ISI. Turbo BER performance reaches 0.8-1.6 dB from capacity with a 4-16 state codes. Feedforward codes perform better than recursive systematic.
  •  
6.
  • Anderson, John B (författare)
  • Coded modulation by outright filtering
  • 2002
  • Ingår i: Proceedings 2002 IEEE International Symposium on Information Theory (Cat. No.02CH37371). - 0780375017 ; , s. 471-471
  • Konferensbidrag (refereegranskat)abstract
    • We investigate the bandwidth and distance of codes created by ordinary lowpass filtering of a pulse stream. The encoder is thus a convolution, but over the reals. Performance of these codes is compared to the TCM and PRS code families; despite their simplicity, the new codes perform equally well. Since a simple decoder exists, these are attractive codes.
  •  
7.
  • Anderson, John B, et al. (författare)
  • Coded Modulation Systems
  • 2003
  • Ingår i: Kluwer Academic / Plenum Publishers. - 0306472791
  • Bok (övrigt vetenskapligt/konstnärligt)abstract
    • This textbook studies the 3 main types of coded modulation: trellis-coded modulation (TCM), continuous-phase modulation (CPM) codes, and linear modulation codes like those that arise from filtering and intersymbol interference. In 2 final chapters, code-division multiple-access receivers are discussed. The book begins with a review of coding, modulation and information theory.
  •  
8.
  • Anderson, John B (författare)
  • Digital Transmission Engineering
  • 2005
  • Bok (övrigt vetenskapligt/konstnärligt)abstract
    • This textbook is a 4th year(Sweden)/5th year (USA) text in digital communication theory and practice. Chapters include baseband pulse transmission, carrier transmission, synchronization, channels, coding and information theory, and advanced topics. Each chapter ends with 25 home exercises. Worked examples and Matlab tools are integrated with the text.
  •  
9.
  • Anderson, John B, et al. (författare)
  • Faster-Than-Nyquist Signaling
  • 2013
  • Ingår i: Proceedings of the IEEE. - 0018-9219. ; 101:8, s. 1817-1830
  • Tidskriftsartikel (refereegranskat)abstract
    • In this paper, we survey Faster-than-Nyquist (FTN) signaling, an extension of ordinary linear modulation in which the usual data bearing pulses are simply sent faster, and consequently are no longer orthogonal. Far from a disadvantage, this innovation can transmit up to twice the bits as ordinary modulation at the same bit energy, spectrum, and error rate. The method is directly applicable to orthogonal frequency division multiplex (OFDM) and quadrature amplitude modulation (QAM) signaling. Performance results for a number of practical systems are presented. FTN signaling raises a number of basic issues in communication theory and practice. The Shannon capacity of the signals is considerably higher.
  •  
10.
  • Anderson, John B, et al. (författare)
  • New reduced state space BCJR algorithms for the ISI channel
  • 2009
  • Ingår i: Proceedings, International Symp. on Information Theory. - 9781424443130 ; , s. 889-893
  • Konferensbidrag (refereegranskat)abstract
    • A critical component in detection under intersymbol interference (ISI) and in turbo equalization is the BCJR algorithm. We study two approaches to reducing its computation. First, the state space is reduced by optimizing the receiver's phase-maximizing all pass filter. Then the state space used by the BCJR calculation is reduced by breaking the state into an offset and a main state. These procedures are demonstrated by ISI detection and turbo equalization over strongly bandlimited channels.
  •  
Skapa referenser, mejla, bekava och länka
  • Resultat 1-10 av 91
Typ av publikation
konferensbidrag (57)
tidskriftsartikel (25)
bok (8)
bokkapitel (1)
Typ av innehåll
refereegranskat (81)
övrigt vetenskapligt/konstnärligt (10)
Författare/redaktör
Öwall, Viktor (28)
Rusek, Fredrik (22)
Eriksson, Tomas (14)
Sjöland, Henrik (10)
Rodrigues, Joachim (4)
Nilsson, Peter (2)
visa fler...
Johansson, Anders J. (2)
Edfors, Ove (2)
Aalto, Susanne, 1964 (1)
Jutte, E. (1)
Battersby, C. (1)
Chin, Gordon (1)
Hunt, L. K. (1)
Rigopoulou, D. (1)
Stark, Antony A. (1)
Viti, Serena (1)
Walker, Christopher ... (1)
Wilner, D.J. (1)
Moldon, J. (1)
Kappes, A. (1)
Naqvi, Muhammad, 198 ... (1)
Cornelissen, J. Hans ... (1)
Gough, Laura (1)
Koopmans, L. V. E. (1)
van der Horst, A. J. (1)
Kadler, M. (1)
Hardcastle, M. J. (1)
Stoica, Peter (1)
Orru, E. (1)
Coolen, A. H. W. M. (1)
Gunst, A. W. (1)
Wijnholds, S. J. (1)
Damstra, Sieds (1)
Ruiter, Mark (1)
Nyström, Marcus (1)
Nelles, A. (1)
Svensson, Arne, 1955 (1)
Luo, Yiqi (1)
Li, Jian (1)
Conway, John, 1963 (1)
Falcke, H.D. (1)
van Bemmel, I. (1)
Li, Wei (1)
Alatalo, Juha M. (1)
Jägerbrand, Annika K ... (1)
De Beck, Elvire, 198 ... (1)
Anderson, J. M. (1)
Ali, Qasim (1)
Hesselstrand, Roger (1)
Allen, John (1)
visa färre...
Lärosäte
Lunds universitet (86)
Chalmers tekniska högskola (4)
Uppsala universitet (1)
Stockholms universitet (1)
Högskolan i Gävle (1)
Jönköping University (1)
visa fler...
Karlstads universitet (1)
visa färre...
Språk
Engelska (91)
Forskningsämne (UKÄ/SCB)
Naturvetenskap (3)
Medicin och hälsovetenskap (1)

År

Kungliga biblioteket hanterar dina personuppgifter i enlighet med EU:s dataskyddsförordning (2018), GDPR. Läs mer om hur det funkar här.
Så här hanterar KB dina uppgifter vid användning av denna tjänst.

 
pil uppåt Stäng

Kopiera och spara länken för att återkomma till aktuell vy