This thesis deals with design and implementation of mapping of match action tables from P4 language to FPGA technology. Goal of the thesis was to describe key principles, which need to be understood in order to design such a mapping and function of algorithms needed, apply these principles by implementing them and analyze the speed and memory requirements of such an implementation. Outcome provides configurable hardware unit capable of classifying packets and connection between the unit and match action tables from P4 language. The implementation is based on DCFL algorithm and requires less memory compared to HiCuts and HyperCuts algorithms while being comparably fast at worst-case scenarios.

P4 is a high-level language for programming the data plane of a network switch. These P4-programmable switches come with no pre-defined behavior or protocols, so it is entirely up to the loaded P4 program to define these. This allows the user to exclude any unwanted functionality and to create custom protocols. It also removes the dependence on the switch vendor in terms of both trust and addition of new features. This thesis looks at migration from traditional switches to P4-programmable ones. Since no behavior is included out-of-the-box in the P4 switches, a search is made for open-source P4 projects and the functionality they provide is evaluated. It is found that most link layer functionality can be achieved with them, with the exception being loop prevention by spanning tree protocols. Therefore, one of the projects is extended with an implementation of the Rapid Spanning Tree Protocol based on the IEEE 802.1D-2004 standard. Finally, partial migration of networks to P4 switches and to the Software Defined Networking (SDN) paradigm is studied based on a literature review. Four general approaches and specific architectures for these are found, and it is concluded that such a hybrid network can still benefit from P4 and having a centralized SDN controller.

Huvudsyftet med denna uppsats är att undersöka varför människor i ålderskategorin 35-49 år inte lyssnar på radiokanalen P4 Västmaland, en av Sveriges Radios 26 st P4 kanaler. Den andra punkten som analyserats är, varför P4 Västmanlands publik lyssnar på kanalen. Med hjälp av fokusgruppsintervjuer via sociala media Facebook undersöks 15 personer uppdelade i två fokusgrupper: P4s lyssnare och icke lyssnare. Det gemensamma för båda grupperna är radiolyssnande som intresse och ålderskategorin. Tillsammans har grupperna genererat ca 234 facebook-inlägg, som utgör grundmaterialet till denna studie. En kompletterande enkät finns med som stöd inför analysdelen samt en intervju med P4 Västmanlands programledare, Annika Nordin. Denna studie använder sig främst av medieteoretikern, Barbara Thomass (2003) teoretiska perspektiv om public sphere (Habermas, 1989) och knowledge society sammankopplat till Public Service. Studiens resultat visar att majoriteten i målgruppen icke-lyssnare uppfattar kanalen som omodern. Denna uppfattning delas även av P4s egna lyssnare. Studien visar att Icke-lyssnarna inte tycker att lokala nyheter är viktiga.  När det gäller hur man tar reda på nationella och internationella nyheter är det framförallt webben, inte radio, som är det prioriterade alternativet för den sistnämnda gruppen. Studien visar även att för båda grupperna är datavana avgörande för hur man interagerar med medier och konsumerar nyheter. Slutsatsen av studien är att om P4 Västmanland upplevs som omodern, så kan detta vara ett hinder för radiokanalen att rekrytera nya lyssnare. Kanalen måste hitta en balans för att främja både sin egen publik, som efterfrågar variation i lokala nyheter, och samtidigt nå flera lyssnare i åldersgruppen mellan 35 och 49 år. Båda grupperna signalerar att möjligheten till interaktion via nya medier bör tas tillvara i dessa nya tider. / The main purpose of this thesis is to examine why people aged between 35-49 years are not listening to the Public Service radio channel P4 Västmanland, one of Swedish Radio´s 26 local channels. The second point has been analyzed is why P4 Västmanland audience listens to the channel. With the help of focus group interviews via social media site Facebook we examined 15 individuals divided into two focus groups: P4 listeners and non-listeners. Listening to the radio for pleasure is common to both groups, who are in the same age category. Together the groups are generated from about 234 Facebook posts, which are the basic material for this study. A supplemental questionnaire is included as a pre-analysis portion as well as an interview with P4 Västmanland journalist, Annika Nordin. This study mostly uses Barbara Thomass' (2003) theoretical perspectives on the public sphere (Habermas, 1989) and knowledge society linked to the Public Service. Our results demonstrate that the majority of the target non-listeners perceive the channel as outdated; this view is also shared with the P4's listeners. The study shows that non-listeners do not think local news is important. When it comes to how to get in contact with national and international news, it is primarily the Web, not the radio, which is the priority choice for the latter group. The study also shows that for both groups, computer access is crucial to how people interact with media and consume news. The conclusion of this study is that if the P4 Västmanland channel is perceived as outdated, so this may be an obstacle to the radio channel to recruit new listeners. The channel must find a balance in order to promote it´s own audience, which require the variation in local news, while reaching more listeners in the  35 and 49 age group. Both groups indicate that the potential for interaction through new media should be utilized in these new times. / A função principal deste estudo é analisar a razão pela qual pessoas na faixa etária de 35 a 49 anos não têm interesse na programação da emissora pública de rádio, P4 Västmanland, um dos 26 canais locais da Suécia. Em contrapartida, a outra questão a ser analisada refere-se à razão pela qual os ouvintes do canal citado, têm interesse na programação.  Este estudo utiliza-se do método de entrevista de foco realizado através da mídia social Facebook e tem como participantes 15 pessoas divididas em dois grupos: ouvintes da P4 Västmanland e ouvintes de outras emissoras de rádio suecas. O fator comum entre os grupos é o interesse por programas de rádio e o fato de serem da mesma faixa etária. A base do material de estudo é composta por aproximadamente 234 comentários realizados através da mídia social Facebook. O estudo dispõe também de uma enquete feita com os participantes e uma entrevista com a jornalista Annika Nordin,  locutora de um dos programas da rádio P4 Västmanland. O estudo se utiliza, em primeiro plano, das perspectivas teóricas de Barbara Thomass (2003) a respeito de public sphere ( Habermas, 1989) e knowledge society acopladas ao ideal de emissoras púbicas de rádio e TV. O resultado do estudo mostra que a maioria dos não -  ouvintes da P4 Västmanlands consideram o canal como antiquado, fator que também foi verificado entre os próprios ouvintes da rádio. Além disso, os não-ouvintes relatam não considerarem importante o noticiário local. A respeito do consumo de notícias nacionais e internacionais, o estudo mostra que a internet, para o último grupo citado, é o meio de comunicação priorizado para se ter acesso à informação. O estudo mostra ainda que o acesso à internet define o modo de interação com os meios de comunicação  e consumo de notícias, de modo geral. O estudo chega à conlusão de que se a emissora de rádio P4 Västmanland é vista como antiquada, torna-se, assim, difícil o recrutamento de novos ouvintes. A emissora em questão necessita de um equilíbrio para agradar seus próprios ouvintes , que estão em busca de um conteúdo variado no que diz respeito à abordagem de notícias locais e, ao mesmo tempo, adquirir novos ouvintes na faixa etária de 35 a 49 anos. Os dois grupos de participantes mostram também que as novas possibilidades de interação mediática precisam ser utilizadas em maior escala na atualidade.

L’Ins(1,4,5)P3 joue un rôle évident dans la signalisation cellulaire : il permet la libération du Ca 2+ des stocks intracellulaires par son action au niveau de récepteurs spécifiques. Pour mettre fin à son action, l’Ins(1,4,5)P3 peut être dégradé par une Ins(1,4,5)P3 5-phosphatase en Ins(1,4)P2, un métabolite inactif. L’Ins(1,4,5)P3 peut aussi être transformé en Ins(1,3,4,5)P4 par une Ins(1,4,5)P3 3-kinase. L’Ins(1,3,4,5)P4 semble posséder des capacités de signalisation propres ou au contraire liées à celles de l’Ins(1,4,5)P3. L’Ins(1,3,4,5)P4 est aussi le point de départ de toute une série d’inositol hautement phosphorylés, dont les rôles ne sont pas clairs. Trois isoformes de l’Ins(1,4,5)P3 3-kinase existent (A, B et C). Ces isoformes possèdent un domaine catalytique carboxy-terminal bien conservé. Par contre, les domaines amino-terminaux sont spécifiques et leur permettraient d’établir des interactions ou de subir des régulations propres. Pour tenter d’élucider le rôle fonctionnel de l’Ins(1,3,4,5)P4, nous avons généré et analysé des souris déficientes pour les isoformes B et C de cette enzyme. Les souris déficientes pour l’Ins(1,4,5)P3 3-kinase C ne présentent pas de phénotype évident, ce qui suggère que son rôle n’est pas crucial ou que son absence peut être compensée par une autre enzyme. Les souris déficientes pour l’Ins(1,4,5)P3 3-kinase B, par contre, présentent une immunodéficience caractérisée par une absence spécifique des lymphocytes T αβ périphériques. Cette absence fait suite à un blocage dans la différenciation du précurseur du lymphocyte, le thymocyte. Les caractéristiques de la signalisation induite par le récepteur de surface (TCR) permettent la sélection des thymocytes, de manière à constituer un pool de lymphocytes T restreints pour le MHC et tolérants pour le soi. Nous avons montré que ces phénomènes de sélection étaient défectueux dans les thymocytes mutants, du fait de leur hyporéactivité à la stimulation par le TCR. Le mécanisme responsable de cette hyporéactivité n’est pas encore élucidé. A première vue, la mobilisation de Ca 2+ ne semble pas altérée dans ces thymocytes mutants en réponse à des stimulations classiques. Cependant, d’autres types de stimulation, se rapprochant plus de celles réellement rencontrées par le thymocyte in vivo, doivent encore être investigués. L’intégrité d’autres voies de signalisation cruciales du lymphocyte T doit aussi être vérifiée. En conclusion, l’isoforme B de l’Ins(1,4,5)P3 3-kinase et l’Ins(1,3,4,5)P4 qu’il produit jouent un rôle crucial dans la différenciation du thymocyte, par un mécanisme qui reste encore à déterminer.

Les membranes plasmiques et les membranes du trans-Golgi des cellules eucaryotes présentent une asymétrie des lipides qui les composent, avec les aminophospholipides (APLs : phosphatidylsérine et phosphatidyléthanolamine) enrichis dans le feuillet cytosolique. La dissipation de cette asymétrie est impliquée dans de nombreux processus (patho)physiologiques. Plusieurs études suggèrent que les ATPases P4 sont les candidats les plus probables pour le transport des APLs et le maintien de leur distribution asymétrique ; leur délétion dans la levure inhibe le trafic membranaire. En outre, des études ont montré que les ATPases P4 interagissaient avec les protéines de la famille CDC50 ; cette interaction est essentielle pour l'adressage et peut-être aussi la fonction des ATPases P4. Afin de contribuer à la compréhension du mécanisme de transport des lipides par les ATPases P4, l'objectif de ce travail a été de mettre au point la co-expression fonctionnelle, dans la levure, de l'ATPase P4 Drs2p et de sa protéine partenaire Cdc50p. Nous avons obtenu une fraction membranaire enrichie à 3% avec la protéine Drs2p, majoritairement en complexe avec Cdc50p. L'étude fonctionnelle du complexe nous a permis de mettre en évidence un rôle crucial du phosphatidylinositol-4-phosphate (PI(4)P), un important régulateur du trafic membranaire, au cours d'une étape particulière du cycle catalytique. Nous avons également développé un protocole de purification sur résine streptavidine du complexe Drs2p/Cdc50p. Enfin, comme un site potentiel d'interaction avec le PI(4)P est présent sur l'extrémité C-terminale de Drs2p, nous avons engendré différentes constructions de Drs2p, dans lesquelles une partie de l'extrémité C-terminale a été délétée ; dans une autre construction, l'extrémité N-terminale a également été délétée. Notre travail ouvre la voie à la caractérisation fonctionnelle et structurale détaillée du complexe Drs2p/Cdc50p, et à l'étude du rôle du transport de lipides dans le trafic membranaire.

In radars, matched filters are used in the receiver of the system. Since the target velocity is not known a priori, degradation occurs due to mismatch of the return signal and the matched filter. The performance of the radar can be improved by using a bank of matched filters. The first topic investigated in this work is optimization of the bank of matched filter structure. Two methods are proposed for the design of the parallel filter structure and computations are performed with both methods. The output signal of a radar receiver filter consists not only of the main peak from the target but also of range sidelobes. In a multi-target radar environment, the sidelobes of one large target may appear as a smaller target at another range, or the integrated sidelobes from targets or clutter may mask all the information of another target. The second part of this thesis discusses the methods for decreasing the sidelobe level of the receiver output. Two methods are studied for this purpose. The first is the classical amplitude weighting and the second is the use of an inverse filter that minimizes total sidelobe energy. Both methods decrease the sidelobe levels while bringing a mismatch loss and main peak broadening. For the inverse filter case it is observed that the effect of inverse filter becomes evident as the filter length is increased beyond some point. Finally, the effects of quantization on video signal and the receiver filter coefficients are evaluated. It is observed that 16 bits quantization is sufficient for all kinds of receiver filters tested.

It is necessary to monitor networks namely for diagnostics, troubleshooting, detection of anomalies and suspicious header encapsulations. This thesis aims to design and implement a system for monitoring protocol structure on 10 Gb networks, which will be able to capture packets based on the sequence of encapsulated protocols. To achieve requested throughput some tasks like packet parsing and packet filtering were accelerated in FPGA. Flexibility is achieved by using a tool that maps P4 programs, which define packet parsing process, to VHDL language. Based on the information gained from packet parsing, flow records are created and stored via IPFIX protocol. This information is displayed through a graphical user interface in the form of protocol tree, whose nodes are associated with flow records.

Network downtime is costly for providers of information technology services. One cause of network downtime is link failures. The control plane of the network is the entity responsible for ensuring connectivity upon link failures. The data plane of the network forwards packets at line speed and it is controlled by the control plane. One disadvantage of ensuring connectivity at the control plane level is the time needed to react to a failure. The control plane is several orders of magnitude slower than the data plane. Moving the connectivity responsibility to the quicker data plane has therefore the potential to reduce network downtime. This work explored what level of connectivity robustness can be achieved when implementing data plane connectivity algorithms in today’s high-speed speed programmable switches. A literature study of several data plane connectivity algorithms was conducted. A critical aspect considered in this study was the simplicity of the data plane connectivity mechanism as high-speed programmable switches cannot support arbitrarily complex forwarding function. Data-Driven Connectivity (DDC) was selected as a suitable algorithm due to its high guaranteed connectivity and algorithmic simplicity. DDC was implemented in a virtual network environment using P4 programmable software switches. Our solution automates the generation of the virtual network based on a topology description. It also initializes the switches and generates the specific DDC P4 code for each switch. All the functions of DDC P4 have been tested to verify that each function behaved as expected. The path optimality of DDC P4 after several link failures were evaluated on the emulated Google’s wide area network topology, called B4 (2011). The path optimality evaluation shows that the path stretch of DDC P4, i.e., the gap from the shortest path in the number of hops, is not optimal for about 30% of the possible source/destination node pairs in the topology. The throughput of the DDC P4 was also evaluated along different number of link failures. The throughput results show a linear decrease in steps of 0.4 Mbps depending on which outbound link was utilized, starting from a throughput of 6.3 Mbps in the absence of failures. The current DDC P4 implementation does not scale well due to duplicate code for each destination in the topology. Both improving the scalability of the current implementation and an implementation on a hardware programmable switch remain as future work. / Avbrott i nätverket är kostsamt för leverantörer av informationsteknologitjänster. En orsak till avbrott är länkfel. Nätverkets textit kontrollplan är den entitet som ansvarar för att säkerställa anslutning vid länkfel. Nätverkets textit dataplan vidarebefordrar paket så snabbt som nätverkslänken klarar av, och det styrs av kontrollplanet. En nackdel med att säkerställa anslutning i kontrollplanet är den tid som krävs för att reagera på ett fel. Kontrollplanet är många gånger långsammare än dataplanet. Att flytta anslutningsansvaret till det snabbare dataplanet kan därför korta ner avbrotten i nätverket. Detta arbete undersökte vilken nivå av robusthet i anslutningsbarheten som kanuppnås vid implementering av algoritmer för anslutningsbarhet i dataplanet i dagens programmerbara höghastighetsswitchar. En litteraturstudie av flera dataplananslutningsalgoritmergenomfördes. En kritisk aspekt som beaktades i denna studie var enkelheten i dataplananslutningsmekanismen eftersom programmerbara höghastighetsswitchar inte kan stödja godtyckligt komplex vidarebefordringsfunktion. Datadriven anslutningsbarhet (DDC) valdes som en lämpligalgoritm på grund av dess höga garanterade anslutningsbarhet och algoritmiska enkelhet. DDC implementerades i en virtuell nätverksmiljö med P4-programmerbara mjukvaruswitchar. Vår lösning automatiserar genereringen av det virtuella nätverket baserat på en topologibeskrivning.Den initialiserar också switcharna och genererar den specifika DDC P4-koden för varje switch. Alla funktioner i DDC P4 har testats för att verifiera att varje funktion uppträdde som förväntat. Sökvägsoptimaliteten för DDC P4 efter flera länkfel utvärderades på Googles emulerade Wide Area Network (WAN), kallad B4 (2011). Bedömningen av sökvägsoptimaliteten visar att vägsträckningen för DDC P4, textit d.v.s., avståndet från den kortaste vägen i antalet hopp, inte är optimal för cirka 30 % av de möjliga ursprungs-/ destinationsnodparna i topologin. Genomströmningen av DDC P4 utvärderades också utifrån olika antal länkfel. Genomströmningsresultaten visar en linjär minskning i steg på 0,4 Mbps beroende på vilken utgående länk som användes, med utgångspunkt från en genomströmning på 6,3 Mbps vid frånvaro av fel. Den nuvarande DDC P4-implementeringen skalas inte bra på grund av duplicerad kod för varje destination i topologin. Både förbättring av skalbarheten för den nuvarande implementeringen och en implementering av en hårdvaruprogrammerbar switch kvarstår som framtida arbete.

Software Defined Networking (SDN) has gained popularity and attractiveness in the past years’ thanks to its dynamic and programmable nature. The possibility to decouple the data plane and control plane allows for the implementation of Internet networks in an innovative way. Thanks to its ease in changing flow rules in network switches, SDN allows network resources optimization. In the case of critical applications, an essential aspect is to ensure connectivity on the network even in case of link failures. Even when a failure causes an interruption of connectivity, the challenge also stays in recovering as fast as possible. Nonetheless, the SDN controller should have the policy to decide which pairs of end-hosts to disable connectivity when there is a shortage of resources to keep the most important connections active. In this thesis, we developed a proactive-reactive SDN controller coded in Python that copes with restoring end-hosts connectivity as fast as possible. The controller prioritizes the couples of end-hosts that need connectivity based on their importance. During a shortage of network resources, the connectivity of pairs of end-hosts with low importance is disabled, and the connectivity between the most important couples can be ensured. We tested our solution with a reactive-only SDN controller and a proactive-reactive SDN controller that does not consider any prioritization order between end-hosts connectivity. Both the benchmark SDN controllers were developed in the thesis. Experiments were run on the same network topology, with the same couple of endhosts involved. The comparison between the proactive-reactive and reactive-only controllers showed the first one to be faster in restoring the connectivity after a failure. It saves time restoring the connectivity and has fewer packets lost under certain conditions in the relationship between the switch-to-switch and the switchto-controller transmission delay. The comparison between the proactive-reactive iii controller and the controller with no prioritization confirms that without an ordered queue of priorities, it may be the most important couple of end-hosts to lose connectivity in case of shortages of network resources. To simulate a realistic scenario, the project considers the case study of electric power transmission networks using SDN. In particular, the focus is on reconnecting Phasor Measurement Unit (PMU)s to the power grid to ensure system observability. During our experiments, we adopted the typical measurement transmission frequency used by PMUs (50Hz). The SDN switches are deployed with P4, and the SDN controller is coded in Python. Furthermore, it exploits P4Runtime to communicate with the switches in run-time. / Software Defined Networking (SDN) har vunnit popularitet och attraktionskraft under de senaste åren tack vare sin dynamiska och programmerbara natur. Möjligheten att frikoppla dataplanet från kontrollplanet gör det möjligt att genomföra Internetnät på ett innovativt sätt. Tack vare att det är lätt att ändra flödesreglerna i nätverksväxlar gör SDN det möjligt att optimera nätverksresurserna. När det gäller kritiska tillämpningar är en viktig aspekt att säkerställa konnektiviteten i nätet även vid länkfel. Även när ett fel orsakar ett avbrott i konnektiviteten är utmaningen också att återhämta sig så snabbt som möjligt. Trots detta bör SDNstyrenheten ha en policy för att avgöra vilka par av slutvärdar som ska inaktivera anslutningen när det råder brist på resurser för att hålla de viktigaste anslutningarna aktiva. I den här avhandlingen har vi utvecklat en proaktiv-reaktiv SDN-styrenhet kodad i Python som klarar av att återställa slutvärdarnas anslutning så snabbt som möjligt. Styrenheten prioriterar paren av slutvärdar som behöver anslutning utifrån deras betydelse. Vid brist på nätverksresurser inaktiveras anslutningen för par av slutvärdar med låg betydelse, och anslutningen mellan de viktigaste paren kan säkerställas. Vi testade vår lösning med en enbart reaktiv SDN-styrenhet och en proaktiv-reaktiv SDN-styrenhet som inte tar hänsyn till någon prioriteringsordning mellan slutvärdarnas konnektivitet. Båda riktmärkeskontrollerna SDN utvecklades i avhandlingen. Experimenten genomfördes på samma nätverkstopologi med samma antal slutvärdar. Jämförelsen mellan den proaktivt-reaktiva och den enbart reaktiva kontrollören visade att den förstnämnda kontrollören var snabbare när det gäller att återställa anslutningen efter ett fel. Den sparar tid för att återställa anslutningen och har färre förlorade paket under vissa förhållanden i förhållandet mellan överföringsfördröjningen från switch till switch och från switch till styrenhet. Jämförelsen mellan den proaktiva-reaktiva styrenheten och v styrenheten utan prioritering bekräftar att utan en ordnad kö av prioriteringar kan det vara det viktigaste paret av slutvärdar som förlorar konnektiviteten vid brist på nätverksresurser. För att simulera ett realistiskt scenario används SDN i projektet som fallstudie för elöverföringsnät. Fokus ligger särskilt på att återansluta Phasor Measurement Unit (PMU)s till elnätet för att säkerställa systemets observerbarhet. Under våra experiment antog vi den typiska överföringsfrekvensen för mätningar som används av PMUs (50Hz). SDN-växlarna installeras med P4, och SDN-styrenheten är kodad i Python. Dessutom utnyttjas P4Runtime för att kommunicera med växlarna i körtid.

Submitted by Ricardo Cedraz Duque Moliterno (ricardo.moliterno@uefs.br) on 2016-07-13T23:29:40Z No. of bitstreams: 1 entrega DISSERTA??O SIMEIA.pdf: 2026591 bytes, checksum: 1a9f43b45ba81ae8ce62414bca386df7 (MD5) / Made available in DSpace on 2016-07-13T23:29:40Z (GMT). No. of bitstreams: 1 entrega DISSERTA??O SIMEIA.pdf: 2026591 bytes, checksum: 1a9f43b45ba81ae8ce62414bca386df7 (MD5) Previous issue date: 2016-02-22 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / This dissertation is mainly aimed to do a mapping or not of occurrence of plural reading in the first person of existing verbs in spoken language in the Baiano semiarid region through a sociolinguistic analysis, checking which linguistic and sociocultural factors that contribute or not to this variation.We sought to investigate the hypothesis that there are patterns of variation and quantitative differences among the communities studied, due to: i) the ethnic background; ii) the community isolation and iii) the distance geographic area of the capital city, urbanization center. For this, it was taken as a research topic verbal agreement with the first person plural (P4) in rural communities of the Baiano semi-arid region, this topic has already been investigated by scholars as Silva (2003) and Lucchesi, Baxter and Silva (2009) which focused only in rural communities marked ethnically, Nina (1980), Almeida (2006), Araujo (2012), in addition to the descriptive analysis undertaken by dialectology scholars of the early twentieth century and by Veado (1982). Perceiving that the studies with the theme of the verbal agreement with P4 take, in most cases, as an example urban Brazilian Portuguese and also the study of pronominal switching (we / us), it is believed that this research becomes relevant because it is a work, in a way, unprecedented, once investigates rural speech and search to see specifically how the verb agreement is made with the first person plural in this variety. It drew up a comparative study between the dialects of the Baiano regions: Rio de Contas and Jeremoabo which according to social history are formed by black people (Barra / Bananal community) and white people (Mato Grosso community), located in the municipality communities of Rio de Contas; remaining Indians in Tapera community, Quilombo remnants in Casinhas community; mestizos and whites people in Lagoa do In?cio community, such communities are located in the municipality of Jeremoabo.In conclusion, the characterization of popular Portuguese of the country is marked by the socio-historical influence of each chosen community. Therefore, it can state that the verbal agreement is a variable phenomenon in the Baiano semi-arid region that it has gained trend towards the use of CV. Thus, it is used the theoretical - methodological model of Variationist Sociolinguistics it was found that the contact of ethnic groups, such as the isolation of some of them, resulted in linguistic differences, so that it can?t be ignored that formation of the popular Brazilian Portuguese language has its roots planted in the rural variety. / Esta disserta??o teve como objetivo central realizar um mapeamento da ocorr?ncia ou n?o da marca??o de plural na primeira pessoa dos verbos existentes na l?ngua falada no Semi?rido Baiano atrav?s de uma an?lise sociolingu?stica, verificando quais fatores lingu?sticos e socioculturais contribuem ou n?o para essa varia??o. Buscou-se investigar a hip?tese de existem padr?es de varia??o e diferen?as quantitativas entre as comunidades estudadas, por conta: i) da forma??o ?tnica; ii) do isolamento da comunidade e iii) da dist?ncia espa?o geogr?fico da capital, centro de urbaniza??o. Para isso, tomou-se como t?pico de pesquisa a concord?ncia verbal com a primeira pessoa do plural (P4) em comunidades rurais do semi?rido baiano, t?pico este j? investigado por estudiosos como Silva (2003) e Lucchesi, Baxter e Silva (2009), que centraram apenas em comunidades rurais marcadas etnicamente, Nina (1980), Almeida (2006), Araujo (2012), al?m da an?lise descritiva empreendida por dialet?logos do inicio do s?culo XX e de Veado (1982), entre outros. Observando que os estudos realizados com a tem?tica da concord?ncia verbal com P4 tomam, na maioria das vezes, como amostra o portugu?s brasileiro urbano ou apenas o estudo da altern?ncia pronominal (n?s/a gente), acredita-se que esta pesquisa torna-se relevante por ser um trabalho, de certa forma, in?dito, visto que investiga a fala rural e busca ver, especificamente, como a concord?ncia verbal se realiza com a primeira pessoa do plural nessa variedade. Tra?ou-se um estudo comparativo entre os falares das regi?es baianas: Rio de Contas e Jeremoabo que segundo a s?cio-hist?ria s?o formadas por negros (a comunidade de Barra/Bananal) e brancos (a comunidade de Mato Grosso), comunidades situadas do munic?pio de Rio de Contas; remanescentes de ?ndios na comunidade de Tapera, remanescentes de quilombolas na comunidade Casinhas; mesti?os e brancos na comunidade Lagoa do In?cio, comunidades essas situadas no munic?pio de Jeremoabo. Concluiu-se que a caracteriza??o do portugu?s popular do pa?s est? pautada na influ?ncia s?cio-hist?rica de cada comunidade escolhida. Deste modo, ? poss?vel afirmar que a concord?ncia verbal ? um fen?meno vari?vel na regi?o semi?rida baiana que tem ganhado tend?ncia ao uso da marca??o de plural nas formas verbais. Desse modo, utilizando-se o modelo te?rico-metodol?gico da Sociolingu?stica Variacionista constatou-se que o contato de etnias, tal como o isolamento de algumas delas, implicou em diferen?as lingu?sticas, de modo que n?o se pode desconsiderar que forma??o do portugu?s popular brasileiro tem suas ra?zes fincadas na variedade rural.