Sökning: "error rates"

Visar resultat 11 - 15 av 198 avhandlingar innehållade orden error rates.

1. 11. Low-density parity-check codes : unequal error protection and reduction of clipping effects

   Författare :Sara Sandberg; David Declercq; Luleå tekniska universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Signalbehandling; Signal Processing;

   Sammanfattning : The invention of low-density parity-check (LDPC) codes made reliable communication possible at transmission rates very close to the theoretical limit predicted by Shannon. However, communication close to the Shannon limit requires very long codes and results in long delay and high encoder and decoder complexity. LÄS MER

3. 12. Voronoi Constellations for Coherent Fiber-Optic Communication Systems

   Författare :Shen Li; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; coded modulation; constellation shaping; geometric shaping; forward error correction coding; lattices; Voronoi constellations.; multidimensional modulation formats; Achievable information rates; coherent fiber-optic communications;

   Sammanfattning : The increasing demand for higher data rates is driving the adoption of high-spectral-efficiency (SE) transmission in communication systems. The well-known 1. LÄS MER

4. 13. On finite element schemes for Vlasov-Maxwell system and Schrödinger equation

   Författare :Christoffer Standar; Göteborgs universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Nonlinear Schrödinger equation; Nitsche scheme; Streamline diffusion; Vlasov-Maxwell; a posteriori error analysis; a priori error analysis; hp-scheme; a posteriori error analysis;

   Sammanfattning : This thesis treats finite element schemes for two kind of problems, the Valsov-Maxwellsystem and the nonlinear Schrödinger equation. We study streamline diffusion schemes applied for numerical solution of the one and one-half dimensional relativistic Vlasov-Maxwell system. The study is made both in a priori and a posteriori settings. LÄS MER

5. 14. Breast tomosynthesis – new perspectives on breast cancer screening

   Författare :Kristina Lång; Malmö Diagnostisk radiologi; []
   Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Breast cancer; Breast tomosynthesis; Mammography; Breast cancer screening; Cancer detection rate; Recall rate; False positive rate; Image perception; Reading time; Lesion visualisation; Detection error;

   Sammanfattning : Abstract: Mammography is currently the established method in breast cancer screening, although the sensitivity is known be affected by overlapping tissue concealing tumours. Breast tomosynthesis takes advantage of multiple exposures at different angles reducing the negative effect of obscuring tissue. LÄS MER

7. 15. Towards a Theory of Codes for Iterative Decoding

   Författare :Michael Lentmaier; Institutionen för elektro- och informationsteknik; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; bit error probability; low-density parity-check convolutional code; low-density parity-check code; turbo code; convolutional code; channel coding; iterative decoding; Informatics; systems theory; Informatik; systemteori;

   Sammanfattning : Channel codes in combination with iterative decoding techniques are a both powerful and efficient method to protect data against disturbances in digital communication systems. This thesis deals with various code constructions for block-wise and continuous transmission that have the potential to achieve low bit error rates with iterative decoding, even when operating close to the Shannon limit. LÄS MER