Sökning: "Systemteori"

Visar resultat 26 - 30 av 105 avhandlingar innehållade ordet Systemteori.

1. 26. On LFSR based Stream Ciphers - analysis and design

   Författare :Patrik Ekdahl; Institutionen för elektro- och informationsteknik; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; self-shrinking generator; shrinking generator; E0; A5; sober; stream cipher; LFSR; snow; Informatics; systems theory; Informatik; systemteori;

   Sammanfattning : Stream ciphers are cryptographic primitives used to ensure privacy in digital communication. In this thesis we focus on stream ciphers built using Linear Feedback Shift Registers (LFSRs). Several different stream ciphers are analysed and new attacks are presented. In addition, two new stream ciphers are presented, both based on the same design. LÄS MER

3. 27. Analysis of Some Convolutional Coding Constructions

   Författare :Karin Engdahl; Institutionen för elektro- och informationsteknik; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; turbo-codes; low-density parity-check convolutional codes; low-density codes; PSK; PAM; QAM; coded modulation; multilevel coding; convolutional codes; multilevel modulation; iterative decoding; Informatics; systems theory; Informatik; systemteori;

   Sammanfattning : This thesis focuses on different convolutional coding constructions for digital communication systems, and on methods to analyze these constructions. The work presented in the thesis can be divided into three main areas; error probability bounds for convolutional codes, analysis of multilevel modulation, and investigation of low-density parity-check convolutional codes. LÄS MER

4. 28. Knowing and the Art of IT Management. An inquiry into work practices in one-stop shops

   Författare :Sara Eriksén; Institutionen för informatik; []
   Nyckelord :SAMHÄLLSVETENSKAP; SOCIAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; SAMHÄLLSVETENSKAP; SOCIAL SCIENCES; systems theory; Informatics; IT management; one-stop shops; public service; Knowing; work practice; Informatik; systemteori; Knowing;

   Sammanfattning : New information technology is developing faster than the models, metaphors and methods in use for conceptualizing the sharing and managing of information in organizations, in communities and in society in general. The way we utilize information technology today does not seem to succeed in supporting the everyday work practices through which organizations accomplish their work. LÄS MER

5. 29. Trellis Source Coding Methods for Low Rates and Short Blocks

   Författare :Tomas Eriksson; Institutionen för elektro- och informationsteknik; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Elektronik och elektroteknik; Electronics and Electrical technology; systemteori; Informatik; systems theory; Informatics; image coding; tailbiting source codes; BCJR algorithm; linear congruential recursions; trellis coding; low rate quantization; rate-distortion theory; Systems engineering; computer technology; Data- och systemvetenskap; Signal processing; Signalbehandling;

   Sammanfattning : Trellis quantization is a finite state machine based method for data compression. It is mainly applied to quantizing noise-like sources. In this thesis new trellis codes suitable for low rate quantization are derived. LÄS MER

7. 30. Tales of Tailbiting Codes

   Författare :Marc Handlery; Institutionen för elektro- och informationsteknik; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; maximum-likelihood decoding algorithm; minimum distance; active distance; woven convolutional code; tailbiting termination method; convolutional code; tailbiting code; Informatics; systems theory; Informatik; systemteori;

   Sammanfattning : Tailbiting codes are error correcting codes and can be used in digital transmission systems. They are obtained by terminating convolutional codes into block codes. This thesis consists of an introduction to convolutional and tailbiting codes, and the Papers A--G that include the main results. LÄS MER