Statistical Modeling of Bit-Error-Rates in Asynchronous Multicarrier CDMA and Direct-Sequence CDMA Systems

This paper presents a method for modeling the bit-error-rate (BER) probability density functions (pdf) of asynchronous Multicarrier Code Division Multiple Access (MC-CDMA) and Direct-Sequence Code Division Multiple Access (DS-CDMA) systems. An uplink channel is considered and it is assumed that the only channel distortion introduced by the channel is caused by the timing misalignments. Deterministic spreading sequences are used and the pdfs of each interferer'’s multiple access interference (MAI) are determined as a function of timing offset. A Nakagami-m distribution is fitted to the pdf of the total MAI power and the BER pdf is obtained directly from this Nakagami-m pdf. Both Walsh-Hadamard (WH) and Gold sequences are analyzed and the mean BERs are compared amongst the two multiple access systems for both sets of spreading sequences of varying lengths. The results suggest a higher resistance to MAI in the MC-CDMA technique for the considered environment

Statistical Modeling of Multiple Access Interference Power: a Nakagami-m Random Variable

This paper proposes a statistical model for the total multiple access interference (MAI) power for both Direct-Sequence Code Division Multiple Access (DS-CDMA) and Multicarrier Code Division Multiple Access (MC-CDMA) systems. We consider the use of both Walsh-Hadamard (WH) and Gold spreading codes transmitting over the asynchronous uplink channel. Detailed signal models of both CDMA systems are derived illustrating the production of MAI under asynchronous conditions. The paper demonstrates the Gaussian nature of the total MAI and shows that the probability density function (pdf) of the total MAI power can be very accurately characterized by the Nakagami-m distribution

Variation of specific morphological traits and ploidy level of five "aegilops" l. species in Morocco

Variation of specific morphological traits and ploidy level of five Aegilops L. species in Morocco.The genus Aegilops L. represents an important natural source of useful genes for wheat breeding, with particular emphasis on biotic and abiotic stress resistance. For successful crosses, the primarily step is to select appropriate Aegilops accessions. In this paper, we studied five Moroccan species of an Aegilops collection on the basis of spike structure and chromosome number. Twenty-eight specific morphological characters were used to differentiate the species. Statistical analyses, in particular the DFA, allowed the characterization of the genetic variability of the species; the two first standardized axes explained 96,2% of the total variability and 100% of the entities were classified within their own group. In addition, the dendrogram constructed using morphological data reveals a significant variability within and between species. Cytogenetic study revealed four species, A. geniculata Roth, A. triuncialis L., A. ventricosa Tausch and A. peregrina Maire & Weiller, to be tetraploid. However, A. neglecta Req. ex. Bertol., where only two accessions are represented in the collection, revealed to be hexaploid, and can then be classified as A. neglecta subsp. recta Chennav

A Systematic Review of Tracing Solutions in Software Product Lines

Software Product Lines are large-scale, multi-unit systems that enable massive, customized production. They consist of a base of reusable artifacts and points of variation that provide the system with flexibility, allowing generating customized products. However, maintaining a system with such complexity and flexibility could be error prone and time consuming. Indeed, any modification (addition, deletion or update) at the level of a product or an artifact would impact other elements. It would therefore be interesting to adopt an efficient and organized traceability solution to maintain the Software Product Line. Still, traceability is not systematically implemented. It is usually set up for specific constraints (e.g. certification requirements), but abandoned in other situations. In order to draw a picture of the actual conditions of traceability solutions in Software Product Lines context, we decided to address a literature review. This review as well as its findings is detailed in the present article.Comment: 22 pages, 9 figures, 7 table

Covid-19 entre rumeur et vérité

Depuis le début de cette pandémie qui a provoqué un arrêt brutal de l’activité humaine dans le monde entier, des milliers d’informations sur internet provenant de sources anonymes propagent des rumeurs qui ne cessent d’envahir les réseaux sociaux : de fausses informations sur l’origine du virus, la contamination, les vaccins, les remèdes traditionnels, les médicaments, les possibilités de sa disparition, les mesures sanitaires, le confinement/ dé-confinement, etc (Eddahbi, 2020). Dans ce foisonnement de discours rumoral, nous nous demandons : comment se constitue la rumeur à l’ère de Covid-19 ? Quel est son impact sur les réseaux sociaux ? Dans qu’elle mesure représente-elle un pouvoir d’évocation collectif ?Pour tenter de répondre à ces questions, nous proposons dans cette recherche, d’étudier quelques images rumorales diffusées sur internet dans le contexte de la pandémie de Covid-19, tout en nous intéressant aux stratégies discursives et énonciatives employées dans la construction du discours rumoral. Avant d’entamer notre analyse, il est judicieux de commencer par la présentation du cadre théorique, dans lequel nous nous intéressons à la rumeur comme concept et phénomène social. Nous verrons également quel était l’impact des nouvelles technologies d’information et de communication la diffusion et la circulation du discours rumoral

Modeling and Parameter Extraction of PV Cell Using Single- and Two-Diode Model

Photovoltaic modules operate under a large range of conditions. This combined with the fact that manufacturers provide electrical parameters at specific conditions (STC). The present study proposes a comparison between single and double diode models of solar PV system and ensures the best suited model under specific environmental condition for accurate performance prediction. An important feature of these models is that its parameters can be determined using data commonly provided by module manufacturers on their published datasheets. Accurate determination of these parameters which arose from a diversification of models and methods dedicated to their estimations is still a challenge for researchers. In this paper the single and two diode models have been studied by mathematical methods based on simulated Newton-Raphson iteration method. Newton-Raphson iteration method is solved by MATLAB simulation.

Le regard entre Je et l’Autre

Le temps de sa narration, la voyeuse interdite - qui donne son nom au roman - laisse entrevoir les possibles plus heureux de la condition des femmes algériennes, ici algéroises, de leurs enfants, comme elle montre les verrous opposés à cette libération et en dénonce les contradictions par la mise en scène des actants mâles, ramenés à des perversions qui sont moins une satire qu'une voie vers une compréhension épistémologique d'une société ; celle-ci est décrite en un microcosme qui vaut, par induction, pour le tout social algérien. Toutefois, le roman de Nina Bouraoui marque la désespérante inanité de ce combat où le pouvoir patriarcal et traditionnel l'emporte sans retour, ne laissant que le roman, ses références à la France et à l'Occident comme tremplin des possibles, des espérances, des sursauts, des projections, des luttes pour échapper à l'aliénation d'être femme arabe.Through her narration, the forbidden " voyeuse ", who gives her name to the French title La voyeuse interdite(translated as Forbidden Vision),gives a perspective on the happier possibilities for the lives of Algerian women, specifically here those from Algiers. At the same time, she shows the shackles preventing this libération and also denounces the contradictions through her representation of male actants, reduced to perversions which figure less as a satire than as a path toward the epistemological understanding of a society. The society of Algiers depicted functions as a microcosm which holds true by induction for the whole of Algerian s;ociety. However, the novel by Nina Bouraoui marks the dispairing inanity of this struggle where patriarchal and traditional power have always prevailed, leaving the novel and its references to France and the West as a springboard of possibilities, hopes, projections and struggles to escape from the alienation of being an Arab woman

Book review: Cities in the anthropocene: new ecology and urban politics by Ihnji Jon

In Cities in the Anthropocene: New Ecology and Urban Politics, Ihnji Jon explores how researchers, city planners and the public can develop a bottom-up approach to environmentalism in urban areas, focusing on the cities of Cape Town, Cleveland, Darwin and Tulsa. This book contributes to establishing a new approach to urban research that understands cities as complex environments and stresses the importance of collaboration with communities, finds Bouchra Tafrata. Cities in the Anthropocene: New Ecology and Urban Politics. Ihnji Jon. Pluto Press. 2021