Sökning: "superposition"

Visar resultat 1 - 5 av 105 avhandlingar innehållade ordet superposition.

  1. 1. Hardness of Constraint Satisfaction and Hypergraph Coloring : Constructions of Probabilistically Checkable Proofs with Perfect Completeness

    Författare :Sangxia Huang; Johan Håstad; Rishi Saket; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Combinatorial optimization; approximation; inapproximability; hardness; probabilistically checkable proofs; pcp; perfect completeness; boolean constraint satisfaction problem; csp; graph coloring; hypergraph coloring; direct sum; superposition; label cover; Computer Science; Datalogi;

    Sammanfattning : A Probabilistically Checkable Proof (PCP) of a mathematical statement is a proof written in a special manner that allows for efficient probabilistic verification. The celebrated PCP Theorem states that for every family of statements in NP, there is a probabilistic verification procedure that checks the validity of a PCP proof by reading only 3 bits from it. LÄS MER

  3. 2. Visual ecology of insect superposition eyes

    Författare :Pär A Brännström; Biologiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Animal physiology; tiger beetle; hawkmoth; mayfly; insect; visual ecology; eye design; vision; compound eye; Djurfysiologi;

    Sammanfattning : In the superposition compound eye each rhabdom (light sensitive unit) receives light through many ommatidial facets, while in the apposition compound eye every rhabdom receives light from a single facet. The superposition design increases photon capture, which is an advantage in dark environments. LÄS MER

  4. 3. Ommatidial adaptations for vision in nocturnal insects

    Författare :Rikard Frederiksen; Biologiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Gain of transduction; Information rate; Signal-to-noise ratio; Apposition eye; Optical sensitivity; Nocturnal insects; Superposition eye; Vision;

    Sammanfattning : Nocturnal vision is a demanding task for insects with small eyes. As it gets dimmer the noise imposed by the stochastic nature of photon arrival makes vision unreliable. Despite this, there are quite a number of animal species that are active at night and apparently see well. LÄS MER

  5. 4. Improved Techniques for Retransmission and Relaying in Wireless Systems

    Författare :Chaitanya V. K. Tumula; Erik G. Larsson; Tobias J. Oechtering; Linköpings universitet; []
    Nyckelord :Hybrid-ARQ; relaying schemes; superposition coding; 3GPP- LTE; TECHNOLOGY; TEKNIKVETENSKAP;

    Sammanfattning : The last three decades have seen significant advances in the wireless communication field. As the data rates of wireless systems are increasing, the demand for mobile services also is increasing rapidly. Like other natural resources, radio spectrum suitable for mobile wireless communications is also limited. LÄS MER

  7. 5. HARQ Systems: Resource Allocation, Feedback Error Protection, and Bits-to-Symbol Mappings

    Författare :Chaitanya Tumula V. K.; Erik G. Larsson; Danyo Danev; Ana I. Pérez-Neira; Linköpings universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; HARQ Systems; Resource Allocation; Geometric Programming; 3GPP-LTE; PUCCH Format 2; Complex-field coding; Signal Space Diversity; Optimization; Superposition Coding;

    Sammanfattning : Reliability of data transmission is a fundamental problem in wireless communications. Fading in wireless channels causes the signal strength to vary at the receiver and this results in loss of data packets. To improve the reliability, automatic repeat request (ARQ) schemes were introduced. LÄS MER