Search results for "Codes"

Electromagnetic energy within dielectric spheres

1987

We present exact and approximate analytic expressions for the time-averaged electromagnetic energy within dielectric spheres on the basis of rigorous Mie theory. Such information is of importance for the study of photochemical reactions within atmospheric water spheres. Numerical results show that on the average the energy inside a cloud droplet is enlarged by a factor exceeding 2 compared with that of a sphere of the same radius of the surrounding medium. In regions of resonance peaks the electromagnetic energy may be increased by more than 2 orders of magnitude.

Moderate-to-Strong Turbulence Generation in a Laboratory Indoor Free Space Optics Link and Error Mitigation via RaptorQ Codes

2016

Free Space Optics (FSO) is rapidly gaining interest as a line-of sight communication technology that offers capabilities similar - in terms of bandwidth and transfer rates - to optical fibre, also possessing several advantages compared with traditional radio frequency links. However, FSO link quality can be strongly affected by unfavourable weather conditions and also by the phenomenon of optical turbulence, even in clear sky. In this work, we have implemented an indoor FSO link and generated moderate-to-strong turbulence conditions along the optical path by using heaters and a mechanical ventilation system. In this way, we have been able to investigate the effects of the generated turbulen…

Diagonal space time hadamard codes with erasure decoding algorithm

2005

A major challenge in the area of space time (ST) codes is to find codes suitable for efficient decoding, thus overcoming the problem of many existing ST code designs which require maximum-likelihood (ML) decoding. A solution could be to apply single-input single-output (SISO) channel codes and theory over temporal channel fading to the multi-input single-output (MISO) code construction and classical suboptimum decoding methods. For these purposes, an ST code construction which allows the use of efficient decoding algorithms is described. We propose a concatenated code, where the inner code is the diagonal ST Hadamard (D-STH) code with Paley constructions and the outer code is an algebraic b…

Transducers for the bidirectional decoding of prefix codes

2010

AbstractWe construct a transducer for the bidirectional decoding of words encoded by the method introduced by Girod (1999) in [5] and we prove that it is bideterministic and that it can be used both for the left-to-right and the right-to-left decoding.We also give a similar construction for a transducer that decodes in both directions words encoded by a generalization of Girod’s encoding method. We prove that it has the same properties as those of the previous transducer. In addition we show that it has a single initial/final state and that it is minimal.

On the nonarchimedean quadratic Lagrange spectra

2018

We study Diophantine approximation in completions of functions fields over finite fields, and in particular in fields of formal Laurent series over finite fields. We introduce a Lagrange spectrum for the approximation by orbits of quadratic irrationals under the modular group. We give nonarchimedean analogs of various well known results in the real case: the closedness and boundedness of the Lagrange spectrum, the existence of a Hall ray, as well as computations of various Hurwitz constants. We use geometric methods of group actions on Bruhat-Tits trees. peerReviewed

QR kodu kā tirdzniecības instrumenta atbilstība uzņēmumiem

2021

Tā kā tehnoloģija ir pārņēmusi mārketinga pasauli, visefektīvākais mārketinga veids ir mobilais mārketings, un, mainoties tendencēm, daudzi mārketinga rīki ir praktizējuši, lai sniegtu produktīvu reklāmu. QR kodi pēdējos gados ir kļuvuši par jauno mārketinga tendenci, taču problēma ir tā, vai šie QR kodi patiešām ir produktīvi viņu centienos. Šī pētījuma mērķis ir analizēt, vai uzņēmumi, kas izmanto QR kodus kā savu mārketinga rīku, var sasniegt savus mērķus vai neietekmē mārketinga shēmas, kā arī noskaidrot, vai cilvēki zina QR kodus un vai tie tos ietekmē / piesaista. Pētījuma rezultāti acīmredzami atrisina pētījuma problēmu, uzņēmumi, kas izmanto QR kodus kā mārketinga rīku, sasniedz sav…

Aporocotyle mariachristinae n. sp., and A. ymakara VillalbaFernández, 1986 (Digenea: Aporocotylidae) of the pink cusk-eel, Genypterus blacodes (Ophid…

2012

Aporocotyle mariachristinae n. sp. and A. ymakara Villalba & Fernández, 1986 were collected from the bulbus arteriosus and ventral aorta of pink cusk-eels, Genypterus blacodes (Forster, 1801) from Patagonia, Argentina. A. mariachristinae n. sp. can be distinguished from all the species of Aporocotyle by the asymmetrical extension of posterior caeca (right posterior caecum longer, terminating at the area between mid-level of ovary and posterior body end; left posterior caecum shorter, terminating at the area between mid-level of cirrus sac and posterior to reproductive organs), the distribution of spines along the ventro-lateral body margins and the number of testes. The new species clearly …

Comparison between different sources of atmospheric profiles for land surface temperature retrieval from single channel thermal infrared data

2012

Abstract Different sources of atmospheric water vapor and temperature profiles were used with a radiative transfer model for retrieving land surface temperature (LST) from thermal infrared remote sensing data with the so-called single channel (SC) method. Retrieved LSTs were compared to concurrent ground measurements over homogeneous rice fields to assess the accuracy of the atmospheric profiles. These included radiosonde balloons launched at the test site near-concurrently to satellite overpasses, re-analysis profiles from the National Centers for Environmental Prediction (NCEP), and satellite sounder products from the Atmospheric Infrared Sounder (AIRS) and the Moderate Imaging Spectrorad…

Application of the SKYRAD Improved Langley plot method for the in situ calibration of CIMEL Sun-sky photometers

2007

The in situ procedure for determining the solar calibration constants, originally developed for the PREDE Sun-sky radiometers and based on a modified version of the Langley plot, was applied to a CIMEL instrument located in Valencia, Spain, not integrated into AERONET. Taking into account the different mechanical and electronic characteristics of the two radiometers, the method was adapted to the characteristics of the CIMEL instrument. The iterative procedure for the determination of the solar calibration constants was applied to a 3-year data set. The results were compared with the two sets of experimental calibration constants determined during this period using the standard Langley plot…

Rateless codes implementation, optimization and application to Free Space Optics links affected by optical turbulence

In this work, I have implemented, optimized and tested the most advanced rateless codes available up to now, i.e., RaptorQ codes. In detail, a multiplatform data transmission software has been appositely developed in order to verify the effectiveness of the above-mentioned codes to decrease packet loss and hence to improve the link quality, under different network and channel conditions. Several simulative and experimental investigations have been carried out to evaluate the performance of the encoding and decoding schemes and the relative recovery capabilities under different test scenarios. In particular, I have applied the software embedding RaptorQ codes to Free Space Optics communicati…