Sökning: "factor graphs"
Visar resultat 1 - 5 av 16 avhandlingar innehållade orden factor graphs.
1. Towards the Limits of Nonlinearity Compensation for Fiber-Optic Channels
Sammanfattning : The performance of long-haul coherent optical systems is fundamentally limited by fiber nonlinearity and its interplay with chromatic dispersion and noise. Due to nonlinearity, the signal propagating through the fiber interacts with itself and with the noise generated from the inline amplifiers. LÄS MER
2. On Nonlinear Compensation Techniques for Coherent Fiber-Optical Channel
Sammanfattning : Fiber-optical communication systems form the backbone of the internet, enabling global broadband data services. Over the past decades, the demand for high-speed communications has grown exponentially. One of the key techniques for the efficient use of existing bandwidth is the use of higher order modulation formats along with coherent detection. LÄS MER
3. Serially Concatenated Space-Time Coded Continuous Phase Modulation
Sammanfattning : Certain problems associated with reliable digital wireless communication over a frequency-flat slow Rayleigh fadingchannel are treated, when the transmitted signal is modulated using continuous phase modulation (CPM) due to the desirable properties of CPM. The primary focus of attention is on detection strategies, and the thesis proposes iterative detection algorithms for CPM signals transmitted over frequency-flat slow Rayleigh fading channels. LÄS MER
4. Hardness of Approximating Constraint Satisfaction Problems and Their Variants in Presence of Additional Structural Assumptions
Sammanfattning : This thesis studies how the approximability of some fundamental computational problems is affected by some additional requirements on the structure of the inputs. The problems studied in this thesis belong or are closely related to constraint satisfaction problems (CSPs), which are considered to be one of the most fundamental problems in theoretical computer science. LÄS MER
5. Analytical and Iterative Methods of Computing PageRank of Networks
Sammanfattning : This thesis is about variants of PageRank, methods of PageRank computation and perturbation analysis of a PageRank vector as a stationary distribution of a kind of perturbed Markov chain model. Chapter 2 of this thesis gives closed form formulae for ordinary and lazy PageRanks for some specific simple line graphs. LÄS MER