Submitted by Erika Demachki (erikademachki@gmail.com) on 2015-02-05T19:59:39Z No. of bitstreams: 2 Dissertação - Pedro Henrique Pires de Castro - 2014.pdf: 1908182 bytes, checksum: edac87bddd8346a2bcce5d9b5f00301d (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Erika Demachki (erikademachki@gmail.com) on 2015-02-05T20:00:48Z (GMT) No. of bitstreams: 2 Dissertação - Pedro Henrique Pires de Castro - 2014.pdf: 1908182 bytes, checksum: edac87bddd8346a2bcce5d9b5f00301d (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2015-02-05T20:00:48Z (GMT). No. of bitstreams: 2 Dissertação - Pedro Henrique Pires de Castro - 2014.pdf: 1908182 bytes, checksum: edac87bddd8346a2bcce5d9b5f00301d (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2014-08-04 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Cloud computing is being consolidated as a new distributed systems paradigm, offering computing resources in a virtualized way and with unprecedented levels of flexibility, reliability, and scalability. Unfortunately, the benefits of cloud computing come at a high cost with regard to energy, mainly because of one of its core enablers, the data center. There are a number of proposals that seek to enhance energy efficiency in data centers. However, most of them focus only on the energy consumed by CPU and ignore the remaining hardware, e.g., RAM. In this work, we show the considerable impact that RAM can have on total energy consumption, particularly in servers with large amounts of this memory. We also propose three new approaches for dynamic consolidation of virtual machines (VMs) that take into account both CPU and RAM usage. We have implemented and evaluated our proposals in the CloudSim simulator using real-world traces and compared the results with state-of-the-art solutions. By adopting a wider view of the system, our proposals are able to reduce not only energy consumption but also the number of SLA violations, i.e., they provide a better service at a lower cost. / A computação em nuvem tem levado os sistemas distribuídos a um novo patamar, oferecendo recursos computacionais de forma virtualizada, flexível, robusta e escalar. Essas vantagens, no entanto, surgem juntamente com um alto consumo de energia nos centros de dados, ambientes que podem ter até centenas de milhares de servidores. Existem muitas propostas para alcançar eficiência energética em centros de dados para computação em nuvem. Entretanto, muitas propostas consideram apenas o consumo proveniente do uso de CPU e ignoram os demais componentes de hardware, e.g., RAM. Neste trabalho, mostramos o impacto considerável que RAM pode ter sobre o consumo total de energia, principalmente em servidores com grandes quantidades dessa memória. Também propomos três novas abordagens para consolidação dinâmica de máquinas virtuais, levando em conta tanto o consumo de CPU quanto de RAM. Nossas propostas foram implementadas e avaliadas no simulador CloudSim utilizando cargas de trabalho do mundo real. Os resultados foram comparados com soluções do estado-da-arte. Pela adoção de uma visão mais ampla do sistema, nossas propostas não apenas são capazes de reduzir o consumo de energia como também reduzem violações de SLA, i.e., proveem um serviço melhor a um custo mais baixo.

No description available.

Les centres de données verts de dernière génération ont été conçus pour une consommation optimisée et une meilleure qualité du niveau de service SLA. Cependant,ces dernières années, le marché des centres de données augmente rapidement,et la concentration de la puissance de calcul est de plus en plus importante, ce qui fait augmenter les besoins en puissance électrique et refroidissement. Un centre de données est constitué de ressources informatiques, de systèmes de refroidissement et de distribution électrique. De nombreux travaux de recherche se sont intéressés à la réduction de la consommation des centres de données afin d'améliorer le PUE, tout en garantissant le même niveau de service. Certains travaux visent le dimensionnement dynamique des ressources en fonction de la charge afin de réduire le nombre de serveurs démarrés, d'autres cherchent à optimiser le système de refroidissement qui représente un part important de la consommation globale.Dans cette thèse, afin de réduire le PUE, nous étudions la mise en place d'un système autonome d'optimisation globale du refroidissement, qui se base sur des sources de données externes tel que la température extérieure et les prévisions météorologiques, couplé à un module de prédiction de charge informatique globale pour absorber les pics d'activité, pour optimiser les ressources utilisés à un moindre coût, tout en préservant la qualité de service. Afin de garantir un meilleur SLA, nous proposons une architecture distribuée pour déceler les anomalies de fonctionnements complexes en temps réel, en analysant de gros volumes de données provenant des milliers de capteurs du centre de données. Détecter les comportements anormaux au plus tôt, permet de réagir plus vite face aux menaces qui peuvent impacter la qualité de service, avec des boucles de contrôle autonomes qui automatisent l'administration. Nous évaluons les performances de nos contributions sur des données provenant d'un centre de donnée en exploitation hébergeant des applications réelles. / Next-generation green datacenters were designed for optimized consumption and improved quality of service level Service Level Agreement (SLA). However, in recent years, the datacenter market is growing rapidly, and the concentration of the computing power is increasingly important, thereby increasing the electrical power and cooling consumptions. A datacenter consists of computing resources, cooling systems, and power distribution. Many research studies have focused on reducing the consumption of datacenters to improve the PUE, while guaranteeing the same level of service. Some works aims the dynamic sizing of resources according to the load, to reduce the number of started servers, others seek to optimize the cooling system which represents an important part of total consumption. In this thesis, in order to reduce the PUE, we study the design of an autonomous system for global cooling optimization, which is based on external data sources such as the outside temperature and weather forecasting, coupled with an overall IT load prediction module to absorb the peaks of activity, to optimize activere sources at a lower cost while preserving service level quality. To ensure a better SLA, we propose a distributed architecture to detect the complex operation anomalies in real time, by analyzing large data volumes from thousands of sensors deployed in the datacenter. Early identification of abnormal behaviors, allows a better reactivity to deal with threats that may impact the quality of service, with autonomous control loops that automate the administration. We evaluate the performance of our contributions on data collected from an operating datacenter hosting real applications.

A economia globalizada e os avanços tecnológicos propiciaram um novo modelo de Outsourcing de Tecnologia de Informação (TI): os provedores de serviços de aplicativos (ASP - Application Service Providers). As discussões a respeito de ASP intensificaram-se nos três últimos anos, com a proposta de comercialização do software como um serviço. Quanto maior a interdependência da área de TI com as metas de negócios das organizações, maior a ênfase dada à satisfação das expectativas do cliente quanto aos serviços prestados pelos provedores. No mercado, têm-se adotado os acordos dos níveis de serviços (SLA - Service Level Agreements) como mecanismo de controle das atividades de outsourcing. Porém, essa adoção é nova e imatura, e a literatura é escassa. Tanto os provedores quanto os cliente sentem a necessidade por estruturas de implantação semelhantes às de SLA. Essa carência é ressaltada no caso dos modelos ASP. Propondo-se a contribuir com a compressão do modelo ASP e de SLA para ASP, apresenta-se uma pesquisa exploratória das características desse modelo com SLA, de modelos de qualidade de serviços de outsourcing e finalmente de considerações que devem ser feitas para garantir a qualidade dos serviços ASP, empregando-se os SLA. / The global economy and technological advances propitiated a new model of Information Technology (IT) Outsourcing: the Application Service Providers - ASP. Discussions regarding ASP became more frequent in the last three years because of the new approach of selling software as a service. As the interdependency between the IT area and the business goals of organizations becomes greater, the emphasis on fulfilling the client\'s expectations regarding service rendered by providers becomes stronger. In the market, Service Level Agreements - SLA have been adopted as control mechanisms of outsourcing activities. However, this adoption is new and immature, and the literature on the matter is scarce. Providers and clients feel the need for implementation structures similar to SLA\'s. In lhe case of ASP models, this necessity is emphasized mainly due to the lack of conceptual information on the ASP model. In order to better comprehend lhe ASP and the SLA models for ASP, I am presenting an exploratory research about the characteristics of the new approach with SLA models, outsourcing models of service quality and considerations, which must be carried out to ensure quality of ASP services employing SLA.

INTRODUÇÃO: 50-86% dos pacientes recidivam a hepatite autoimune (HAI) após a suspensão do tratamento imunossupressor. A manutenção da imunossupressão em longo prazo diminui o risco de recidiva, entretanto é necessário ajuste da dose/suspensão do tratamento em 10-30%, em razão do maior risco de neoplasias e infecções. O difosfato de cloroquina (CQ) é droga imunomoduladora que foi utilizada anteriormente em monoterapia para manutenção da remissão da HAI com diminuição da recidiva quando comparada com controle histórico. O objetivo desse estudo foi investigar a eficácia e segurança do CQ na manutenção da remissão em estudo duplo cego e randomizado e avaliar se há um subgrupo com maior benefício ao seu uso. METODOLOGIA: 61 pacientes com diagnóstico provável ou definitivo de HAI em remissão histológica, 90,1% HAI tipo 1; 23% com reatividade do anti-SLA/LP, 56,6% com fibrose avançada (F3/4) à inclusão no estudo, mas com doença hepática compensada, foram randomizados de forma duplo cego e aleatória para receber CQ 250 mg/d ou placebo, durante 36 meses ou até recidiva da doença. No primeiro mês a droga foi utilizada em combinação com a imunossupressão que induziu remissão; com posterior desmame semanal da prednisona, suspensão imediata da azatioprina e manutenção do CQ/placebo até 36 meses. As curvas de sobrevida livre de recidiva foram estimadas pelo método de Kaplan-Meyer e comparadas pelo teste de Log-Rank; as razões de risco e seus respectivos intervalos de confiança foram estimados por regressão simples de Cox. Na regressão múltipla foram avaliadas co-variáveis clinicamente relevantes para recidiva. Para investigar o subgrupo com maior benefício, as interações entre a droga e reatividade de autoanticorpos e perfil de HLA foram analisadas por regressão múltipla de Cox. As variáveis categóricas foram comparadas pelo teste exato de Fisher e as quantitativas pelo teste-t ou teste de Mann-Whitney. Foi considerado estatisticamente significante um valor de p < 0,05. RESULTADOS: 31 pacientes receberam CQ e 30 placebo. Não houve diferenças entre os grupos em relação aos achados clínicos, laboratoriais, histológicos e perfil de HLA. A sobrevida livre de recidiva foi significativamente maior no grupo CQ quando comparada ao placebo (59,3% X 19,9%, p=0,039). Após a suspensão da medicação ao término do estudo, houve 41,6% de recidiva no grupo CQ e 0% no placebo. Na regressão simples de Cox, os fatores associados com recidiva da HAI foram uso placebo, reatividade do anticorpo anti-SLA/LP, perfil de HLA DR3 e DR8. Na regressão múltipla, o uso de placebo (razão de risco de 2,4[IC 95%:1,05- 5,5], p=0,039) e reatividade do anticorpo anti-SLA/LP (razão de risco= 5.4 [IC 95%:1,91-15,3], p=0,002) associaram-se a maior risco de recidiva. Não foi possível definir subgrupo de maior benefício com uso de CQ no que se refere à reatividade do anti-SLA/LP ou perfil de HLA, embora a recidiva tenha ocorrido em 100% dos pacientes anti-SLA/LP(+) no grupo placebo e 50% no grupo CQ. No grupo CQ, 54,8% apresentaram efeitos colaterais, com suspensão da droga em 19,3%. Os efeitos colaterais mais comuns foram prurido e hiperpigmentação cutânea. CONCLUSÕES: O CQ reduziu com segurança o risco de recidiva de HAI, mas não foi possível definir subgrupo com maior benefício com essa medicação / INTRODUCTION: 50-86% of patients relapse autoimmune hepatitis (AIH) after immunosuppressive treatment withdrawal, with a higher risk of progression to liver cirrhosis, death due to liver disease and liver transplantation. The maintenance of long-term immunosuppression decreases the risk of relapse, however, treatment dose adjustment and/or interruption is required in 10-30%, with increased risk of neoplasias and infections. Chloroquine diphosphate (CQ) is an immunomodulatory drug used previously in monotherapy to maintain AIH remission with a decrease risk in relapse rates when compared to a historical control. The aims of this study were to investigate the efficacy and safety of CQ in the maintenance of remission in a double-blind and randomized study, and to evaluate if there is a subgroup with a greater benefit of its use. METHODS: 61 patients with probable or definitive diagnosis of AIH in histological remission, 90.1% type 1; 23% with anti-SLA / LP seropositivity, 56.6% with advanced fibrosis [F3 / 4] at inclusion in the study and with compensated liver disease were randomized double-blindly to receive either CQ 250 mg/day or placebo for 36 months or until relapse. In the first month, the drug was used in combination with the immunosuppressive regimen that induced the remission; with subsequent weekly weaning of prednisone, immediate withdrawal of azathioprine and maintenance of CQ/placebo for up to 36 months. Recurrence-free survival curves were estimated by the Kaplan-Meyer method and compared by the Log-Rank test; the hazard ratios and their respective confidence intervals were estimated by simple Cox regression. Clinically relevant covariables for relapse were re-evaluated bymultiple Cox regression. To investigate the existence of a subgroup with a greater benefit, interactions between the drug and autoantibody reactivity and HLA profile were analyzed by the Cox multiple regression. Categorical variables were compared by Fisher\'s exact test and the quantitative by the t-test or Mann- Whitney test. A p value of < 0.05 was considered statistically significant. RESULTS: 31 patients received CQ and 30 placebo. There were no differences between the two groups in relation to clinical, laboratory, histological and HLA profiles. Relapse-free survival was significantly higher in the CQ group when compared to placebo (59.3% X 19.9%, p=0.039). After antimalarial withdrawal at the end of the study, there was 41.6% relapse in the CQ group and 0% in the placebo. In the Cox simple regression, factors associated with AIH relapse were placebo use, anti-SLA/LP seropositivity, and HLA DR3 and DR8 profiles. In multiple regression, placebo use (Hazard Ratio = 2.4 [95% CI: 1.05-5.5], p = 0.039) and anti-SLA/LP seropositivity (Hazard Ratio = 5.4 [95% CI: 1.91-15.3], p = 0.002) were associated with a higher risk of relapse. It was not possible to define a subgroup with a greater benefit of CQ with respect to anti-SLA/LP positivity or HLA profile, although all anti-SLA/LP(+) patients in placebo group relapsed, compared to 50% in CQ group. In the CQ group, 54.8% had side effects, but 19.3% had drug withdrawal. The most common side effects were pruritus and cutaneous hyperpigmentation. CONCLUSIONS: Chloroquine safely reduced the risk of relapse of AIH, but it was not possible to define a subgroup with greater benefit with medication use

Syftet med denna studie var att undersöka och kartlägga den komplexa språksituationen och - användningen hos en flerspråkig person. Den undersökta personen kallas för Frida. Hon hade redan i ung ålder lärt sig mer än två språk och har sedermera varit i kontakt med sju språk på en signifikant kunskapsnivå. Denna studie ville knyta an till de teorier och modeller som har presenterats i den modernare forskningen kring andra- och tredjespråksinlärning. Undersökningen baserades enbart på Fridas självredogörelser enligt tre kriterier; hennes språkbiografiska bakgrund, språkfärdigheten och hennes attityder gentemot sin egen språksituation och språk i allmänhet. Dessa kriterier undersöktes med hjälp av kvalitativa intervjuer och självbedömningsmallar. Resultaten bekräftade antaganden om att Fridas språkanvändning och –situation idag påverkas av ett komplext samspel mellan ett flertal multifaktorella komponenter som uppstår i en flerspråkig kontext. Kartläggningen av Fridas språkbiografiska bakgrund, hennes språkanvändning och hennes attityder gentemot språken samt medvetenhet har gett inblick i hur de underliggande mekanismerna inom flerspråkighet verkar. / The aim of this study was to explore and analyse the complex language situation and use of a multilingual person. The examined person is called Frida. Already at a young age she had acquired more than two languages and today she has been in relevant contact with around seven languages. This study wanted to connect to the theories and models, which are presented in today’s research on Second and Third Language Acquisition. The study was entirely based on Frida’s self reports according to the following criteria: her background of language acquisition, her proficiency levels and her attitudes and perception towards her own language situation and languages in general. These criteria had been worked out with the help of guided qualitative interviews and a self-assessment grid for the language skills. The results approved that Frida’s language use and situation is affected by the interaction of an amount of multifactorial components, which occur in a multilingual context. This analysis of Frida’s language background, her language use, attitudes and awareness gave an insight into how the underlying mechanisms of multilingualism work.

Le Cloud Computing est un nouveau modèle économique hébergeant les applications de la technologie de l’information. Le passage au Cloud devient un enjeu important des entreprises pour des raisons économiques. La nature dynamique et la complexité croissante des architectures de Cloud impliquent plusieurs défis de gestion. Dans ce travail, nous nous intéressons à la gestion des contrats SLA. Vu le manque de standardisation, chaque fournisseur de service décrit les contrats SLA avec son propre langage, ce qui laisse l'utilisateur perplexe concernant le choix de son fournisseur de services. Dans ce travail, nous proposons une architecture de Cloud Broker permettant d’établir et de négocier les contrats SLA entre les fournisseurs et les consommateurs du Cloud. L’objectif de cette architecture est d’aider l’utilisateur à trouver le meilleur fournisseur en utilisant une méthode multi-critère. Cette méthode considère chaque critère comme une fonction d’utilité à intégrer dans une super-fonction d’utilité. Nous proposons d’illustrer chaque fonction d’utilité par une courbe spécifique à lui représentant bien le critère de choix. Nous essayons de cerner la plupart des critères qui contribuent dans le choix du meilleurs service et de les classer en critères fonctionnels et critères non fonctionnels. Les contrats SLA établit par notre broker sont formalisés sous forme d’ontologies qui permettent de masquer l'hétérogénéité et d’assurer l'interopérabilité entre les acteurs du Cloud. En outre, l’utilisation des règles d'inférence nous a permis de détecter les violations dans le contrat SLA établit et de garantir ainsi le respect de la satisfaction client dans le temps / Cloud Computing is a dynamic new technology that has huge potentials in enterprises and markets. The dynamicity and the increasing complexity of Cloud architectures involve several management challenges. In this work, we are interested in Service Level Agreement (SLA) management. Actually, there is no standard to express Cloud SLA, so, providers describe their SLAs in different manner and different languages, which leaves the user puzzled about the choice of its Cloud provider. To overcome these problems, we introduce a Cloud Broker Architecture managing the SLA between providers and consumers. It aims to assist users in establishing and negotiating SLA contracts and to help them in finding the best provider that satisfies their service level expectations. Our broker SLA contracts are formalized as OWL ontologies as they allow hiding the heterogeneity in the distributed Cloud environment and enabling interoperability between Cloud actors. Besides, by combining our ontology with our proposed inference rules, we contribute to detect violations in the SLA contract assuring thereby the sustainability of the user satisfaction. Based on the requirements specified in the SLA contract, our Cloud Broker assists users in selecting the right provider using a multi attribute utility theory method. This method is based on utility functions representing the user satisfaction degree. To obtain accurate results, we have modelled both functional and non functional attributes utilities. We have used personalized utilities for each criterion under negotiation so that our cloud broker satisfies the best consumer requirements from functional and non functional point of view

Detta är ett examensarbete inom Industriell teknik och produktionsunderhåll som handlar om kundkrav för service av mobilnät i stora industrier. De stora industrierna, som exempelvis Scania och Boliden, har fokus på att underlätta underhåll och hantering av produktionen med hjälp av automation och digitalisering i sina företag. Idag är det nya mobilnätet, 5G, en efterfrågad teknologi i stora industrier med stora produktionsanläggningar, som gör det möjligt att koppla upp de fysiska komponenterna och därmed effektivisera sitt företag. I detta arbete har intervjuer genomförts med tre svenska företag, Ericsson, Scania och Boliden, där de stora kraven med implementering och användning av 5G tagits fram. Utöver den kvalitativ studien har en litteraturstudie genomförts, där kravet var att välja information som inriktar sig på 5G och dess implementering i stora produktionsanläggningar. Målet med detta arbete är att identifiera kundens behov av egen service och kundkrav på operatören vid implementering och användning av 5G, samt komma fram med ett förslag på ett SLA. Resultaten, från intervjuer och litteraturstudie, visar att kundens krav på operatören överväger kundkrav av egen service. Vid implementering av 5G måste industrikunder ställa om hela produktionen, vilket kräver ny utrustning, ny teknik och kompetent personal. Dessa krav ska operatörer, som implementerar och levererar mobilnät, ta hand om. Industrikunder har också krav att kunna själv hantera vissa delar i 5G-mobilnätet, exempelvis att ha tekniker som kan ta hand om enkel underhåll. Detta gör nätet säkrare och effektivare men även billigare, då operatören inte behöver genomföra enklar underhållsarbete. Vidare har ett förslag på ett SLA tagits fram, där vissa krav som industrikunder hade på ett serviceavtal dokumenterades. / The conducted project within the program of Industrial Technology and Production Maintenance concerns the industrial customer requirements for service of mobile networks within large industries. The large industrial customers, such as Scania and Boliden, have an immense focus on supporting the maintenance processes and managing production with the help of automation and digitalization within their companies. Today, the new mobile network of 5G, is a sought-after technology within large industries with large production facilities, that enables the opportunity to connect physical components and thereby increasing the efficiency within the operations. In this thesis work, interviews have been conducted with three Swedish companies, Ericsson, Scania, and Boliden. This is where the requirements of implementation and usage of 5G network have been determined. Moreover, a literature study has also been carried out with the requirement of selecting information that emphasizes on 5G and implementation within large production facilities. The objective of this thesis work is to identify the requirements of large industrial customers, such as their needs for self-maintenance, their requirements on the network operator during implementation and usage of 5G. Finally, the objective is to also present a Service Level Agreement or SLA. The result from the interview and the literature study shows that the customer requirements on the network operator are higher than the requirements the network operator has on thecustomers. During the implementation of 5G, industrial customers must adapt and change their production facilities, which requires new equipment, technology, and competent workers. These aspects should be considered by the and handled by the network operator. Industrial customers also have the condition of handling certain areas of the 5G network themselves, for example having technicians ready that can conduct simple maintenance. This in turn will enable more secure and efficient network and on the same time, at a lesser cost, due to the network operator no longer must conduct simple maintenance. Furthermore, a proposition for a Service Level Agreement have been composed, where the requirements from the industrial customers were documented.

Blockchain seems to be the hot new innovation that brings disruption to many different industries in the form of decentralization. Groups of peers can finally organize and work together without a central actor having an authority over the transactions that occur. Other than decentralization, due to the distributed and cryptographic nature of the data, the system also enjoys resilience, immutability and safety. In this thesis, we are leveraging permissioned blockchain technology to take steps towards a trustless service level agreement (SLA) management system where both service providers and customers lack the power to tamper with the contracts and their outcomes. The thesis yields a systematic literature review on the state-of-the-art within SLA management and relevant blockchain technology, a proof-of-concept working with Ericssons decentralized edge service marketplace, Nubo, and finally asimulation which evaluates how the proof-of-concept performs in terms of throughput and latency under different network loads. The simulation shows that the network works as expected, until 70 transactions per second (TPS) are reached, at which point the network is limited by throughput. / Blockchain ser ut att vara den nya teknologin som leder till stora förändringar i olika industrier i form av decentralisering. En grupp av noder kan till slut organisera sig och arbeta tillsammmans utan en central figur som styr och har kontroll över arbetet. Utöver decentralisering ger blockchain också fördelen av uthållighet, oföränderlighet och säkerhet till systemet tack vare sin kryptografiska grund. I den här studien utnyttjar vi privat blockchainteknologi för att ta steg mot en decentraliserad service level agreement (SLA) platform, där både tjänsteleverantörer och konsumenter saknar makten att manipulera kontrakt och dess resultat. Studien ger en systematisk literaturstudie på state-of-the-art inom SLA och relevant blockchain teknologi, ett bevis på koncept som fungerar tillsammans med Ericssons decentraliserade Nubo Service Marknad, och till slut en simulation som undersöker hur systemet reagerar i form av genomströmmning och responstid under olika nätverksbelastningar. Undersökningen visar att nätverket fungerar som förväntat upp till 70 transaktioner per sekund, då nätverket begränsas av genomströmning och köer bildas.

The purpose of this paper is to examine in depth and to synthesize the literature on foreign language anxiety, with specific focus on speaking anxiety. This paper reviews the development of the foreign language anxiety construct and extensive research on its relationship with other domains of second language acquisition, including specific language skills and language learning processes. Review of the literature has confirmed that foreign language anxiety plays a significant role in learners’ performance and achievement. However, there are still many areas that need further research and clarification. Variables such as individual differences still cloud the relationship between anxiety and achievement, thus suggesting that further research should be conducted in order to clarify the effects of foreign language anxiety and should strive to alleviate learners’ anxiety in the language classroom. / text