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Esta investigación se centra en la formación inicial del profesorado, irrumpe en el campo de la didáctica de la historia y en los fundamentos teóricos y metodológicos de las diferentes tradiciones sobre las finalidades, se encuadra en el paradigma crítico, adopta una perspectiva cualitativa y recurre a la investigación-acción y al estudio de casos para atender situaciones vinculadas con la práctica profesional de un grupo de estudiantes de maestro en el contexto del sistema educativo mexicano. El trabajo parte de la caracterización de las diferentes tradiciones para disponer de un referente que ayude a identificar dónde se ubican las estudiantes. Enseguida, por medio de un cuestionario y una entrevista en profundidad se describen, analizan e interpretan los rasgos distintivos del modelo didáctico que utilizaban sus maestros de historia durante la educación básica y el bachillerato. El aprendizaje por observación se concibe como la fuente principal para definir el estilo de enseñanza de las normalistas y por esa razón, más adelante se emplea una planeación propia para que comparen las dimensiones tratadas en las representaciones con las que ponen en práctica cuando enseñan historia. Por último, redactan un texto sobre el ideal formativo que se deriva de la secuencia para disponer de una marca que permita juzgar si al final del proceso evolucionaron hacia otras propuestas sobre las finalidades y la enseñanza de la historia. Esta actividad es similar a un diagnóstico e incluye evidencias sobre la decisión de las estudiantes a participar en un espacio formativo que incorpora la presentación, análisis y puesta en práctica de otros proyectos didácticos. La siguiente fase está orientada a generar esquemas de actuación y reflexión que superen las representaciones iniciales, en cuanto a la capacidad para describir, explicar, justificar y argumentar la enseñanza de la historia desde diversos tipos de finalidades. La adquisición de competencias se desarrolla en reuniones de seminario donde las normalistas se implican en la resolución de las situaciones problemáticas que se plantean. En ese momento, se recopilan documentos escritos sobre la habilidad para correlacionar las finalidades con los elementos didácticos de las tradiciones, analizar de manera crítica los materiales curriculares de la educación primaria y valorar sus experiencias como alumnas y maestras de historia. La fase final está destinada a experimentar diferentes perspectivas para enseñar historia (afines a un nuevo ideal formativo) y evaluar de forma sistemática su capacidad para alcanzar las finalidades que se promueven. En esta etapa las evidencias se concatenan entre sí, desde la programación de la acción (planeaciones y diarios de campo), la práctica en el aula (guía de observación, grabación en audio, diarios de clase, productos de aprendizaje), hasta la reflexión posterior sobre las tensiones que aparecen al articular las ideas o intencionalidades, la consistencia lógica en el diseño curricular y su puesta en práctica. Los resultados de la investigación indican que el cambio didáctico ha de concebirse como una mejora en los conocimientos, habilidades y actitudes que se requieren para enseñar, un trayecto que ha de comenzar desde el ingreso a las instituciones formadoras de docentes y realizarse de manera continua, aunque también queda constatada la posibilidad de que la tradición crítica sea una opción desde la formación inicial. De cualquier modo, el conocimiento que se obtiene es relativo a un marco específico y por eso, la transferibilidad de los descubrimientos a otros entornos ha de tomar en cuenta las similitudes, correspondencias y circunstancias de cada objeto de estudio., This research focuses on initial teacher training, bursts into the field of teaching history and the theoretical and methodological traditions of different purposes on fundamentals, falls within the critical paradigm adopts a qualitative perspective and uses action research and case studies to address situations related to professional practice of a group of student teachers in the context of the Mexican educational system. The working part of the characterization of different traditions to provide a benchmark to help identify where students are located. Then, by means of a questionnaire and an interview in depth are described, analyzed and interpreted the distinctive features of the teaching model used their history teachers for basic education and high school. Observational learning is seen as the main source to define the style of teaching normalistas and for that reason, later a planning itself is used for comparing the treated dimensional representations with which implemented when teaching history. Finally, write a text on the normative ideal which is derived from the sequence to have marked so as to judge whether the end of the process evolved into other proposals on the aims and teaching of history. This activity is similar to a diagnosis and includes evidence on the decision of the students to participate in a training environment that incorporates the presentation, analysis and implementation of other educational projects. The next phase is aimed at generating schemes of action and reflection that exceed the initial representations regarding the ability to describe, explain, justify and argue the teaching of history from a variety of purposes. The acquisition of skills developed in seminar meetings where normalistas are involved in resolving problem situations that arise. At that time, written documents are collected on the ability to correlate the purposes for teaching elements of traditions, critically analyze curriculum materials for primary education and evaluate their experiences as students and teachers of history. The final phase is destined to experience different perspectives to teach history (akin to a new training ideal) and systematically assess their ability to achieve the goals that are promoted. At this stage the evidence are concatenated together, from scheduling action (plannings and field diaries), classroom practice (observation guide, audio recording, daily class learning products), to the reflection back on the tensions that appear to articulate ideas or intentions, logical consistency in curriculum design and implementation. The research results indicate that educational change has to be conceived as an improvement in knowledge, skills and attitudes required for teaching, a path must start from admission to teacher training institutions and conducted continuously, but also is proven the possibility that the critical tradition an option from initial training. However, the knowledge gained is relative to a specific context and therefore, the transferability of the findings to other settings must take into account the similarities, correspondences and circumstances of each study subject.

Hem llegit amb molt d'interès la carta del Dr. Natal i col.l. referent al nostre article 'Són realment infreqüents les fractures d'ós llarg en menors de dos anys?'. El nostre estudi tenia com objectiu determinar la freqüència diagnòstica de fractures d'ossos llargs en els infants atesos a Urgències i les característiques que presentaven. Com que es tractava d'un estudi retrospectiu, hi ha dades que no es van poder esbrinar perquè no constaven a la història clínica. El que sí que podem confirmar és que no es van diagnosticar maltractaments en cap dels casos.

Podeu consultar la Setena trobada de professorat de Ciències de la Salut completa a: http://hdl.handle.net/2445/43352, En 2011, se aplicó la metodología del aprendizaje basado en problemas (ABP) en los seminarios prácticos de Pediatría a los estudiantes de 6º de Medicina. La ABP invierte la organización tradicional de los procesos de aprendizaje: primero se presenta el problema, ya partir de la delimitación de lo que ya se conoce, se establecen los objetivos, se identifican las necesidades de aprendizaje, y se diseña y se sigue un plan de actuación, para que el aprendizaje se acompañe de la reso-lución del problema. Previamente, los profesores realizaron un curso específico so-bre ABP organizado por el IES. Transcurrido el primer curso de aplicación del ABP, se pretende evaluar el grado de satisfacción y de aprendizaje obtenidos de los seminarios prácticos ba-sados en el ABP por parte de los estudiantes.

Fonament. Les fractures són habituals entre les lesions no intencionades de la infància, però es creu que són poc fre- qüents en lactants. Objectiu. Determinar la freqüència diagnòstica i les caracte- rístiques de les fractures produides en nens menors de 2 anys. Mètode. Estudi retrospectiu de les consultes d'infants menors de 2 anys diagnosticats de fractura d'os llarg a urgències. Resultats. S'inclouen 258 consultes (prevalença 0,2%), el 25,2% de les quals corresponen a infants de menys d'1 any. Es van diagnosticar 293 fractures (35 infants en pre- sentaven dues). L'os més fracturat va ser el radi (en menors d'1 any, el fèmur), i la fractura en rodet, el tipus més ha- bitual. En 196 consultes (76%) se n'especifica la causa, i les més freqüents són caigudes i traumatismes. El 15,1% dels pacients van necessitar ingressar. Conclusions. Les fractures d'os llarg, tot i que són poc fre- qüents en lactants, presenten una morbiditat elevada. És important fer una anamnesi exhaustiva per esclarir-ne la causa i poder aplicar mesures preventives

The Cloud computing paradigm is offering an innovative and promising vision concerning the Information and Communications Technology (ICT). Actually, it gives the possibility of improving IT systems management and is changing the way in which hardware and software are designed and purchased. Notwithstanding, the use of Cloud resources, which usually are external assets to their consumers, implies risk issues that must be taken into account. In this paper, we propose the involvement of risk management procedures into Cloud computing. In this sense, we present a Cloud computing risk management approach aware of Business- Level Objectives (BLOs) of a given Cloud organization. More to the point, we propose an innovatory SEmi-quantitative BLOdriven Cloud Risk Assessment (SEBCRA) as the core subprocess of this Cloud risk management approach. In addition, we present, as a use case, a Cloud Service Provider (CSP) that is able to improve the achievement of a given BLO, i.e. profit maximization, by managing, assessing, and treating Cloud-related risks. As demonstrated in the experimentation, this provider maximizes its profit by transferring the risks of provisioning its private Cloud, either under- or over-provisioning, to third-party Cloud Infrastructure Providers (CIPs).

For a non IT expert to use services in the Cloud is more natural to negotiate the QoS with the provider in terms of service-level metrics –e.g. job deadlines– instead of resourcelevel metrics –e.g. CPU MHz. However, current infrastructures only support resource-level metrics –e.g. CPU share and memory allocation– and there is not a well-known mechanism to translate from service-level metrics to resource-level metrics. Moreover, the lack of precise information regarding the requirements of the services leads to an inefficient resource allocation –usually, providers allocate whole resources to prevent SLA violations. According to this, we propose a novel mechanism to overcome this translation problem using an online prediction system which includes a fast analytical predictor and an adaptive machine learning based predictor. We also show how a deadline scheduler could use these predictions to help providers to make the most of their resources. Our evaluation shows: i) that fast algorithms are able to make predictions with an 11% and 17% of relative error for the CPU and memory respectively; ii) the potential of using accurate predictions in the scheduling compared to simple yet well-known schedulers.

Crash and omission failures are common in service providers: a disk can break down or a link can fail anytime. In addition, the probability of a node failure increases with the number of nodes. Apart from reducing the provider’s computation power and jeopardizing the fulfillment of his contracts, this can also lead to computation time wasting when the crash occurs before finishing the task execution. In order to avoid this problem, efficient checkpoint infrastructures are required, especially in virtualized environments where these infrastructures must deal with huge virtual machine images. This paper proposes a smart checkpoint infrastructure for virtualized service providers. It uses Another Union File System to differentiate read-only from read-write parts in the virtual machine image. In this way, read-only parts can be checkpointed only once, while the rest of checkpoints must only save the modifications in read-write parts, thus reducing the time needed to make a checkpoint. The checkpoints are stored in a Hadoop Distributed File System. This allows resuming a task execution faster after a node crash and increasing the fault tolerance of the system, since checkpoints are distributed and replicated in all the nodes of the provider. This paper presents a running implementation of this infrastructure and its evaluation, demonstrating that it is an effective way to make faster checkpoints with low interference on task execution and efficient task recovery after a node failure.

As energy-related costs have become a major economical factor for IT infrastructures and data-centers, companies and the research community are being challenged to nd better and more efficient power-aware resource management strategies. There is a growing interest in "Green" IT and there is still a big gap in this area to be covered. In order to obtain an energy-efficient data center, we propose a framework that provides an intelligent consolidation methodology using di erent techniques such as turning on/o ff machines, power-aware consolidation algorithms, and machine learning techniques to deal with uncertain information while maximizing performance. For the machine learning approach, we use models learned from previous system behaviors in order to predict power consumption levels, CPU loads, and SLA timings, and improve scheduling decisions. Our framework is vertical, because it considers from watt consumption to workload features, and cross-disciplinary, as it uses a wide variety of techniques. We evaluate these techniques with a framework that covers the whole control cycle of a real scenario, using a simulation with representative heterogeneous workloads, and we measure the quality of the results according to a set of metrics focused toward our goals, besides traditional policies. The results obtained indicate that our approach is close to the optimal placement and behaves better when the level of uncertainty increases.

Commercialization of computing resources will become more and more important as the transition from Grid computing in academic environments to commercial services based on concepts such as utility or Cloud computing progresses. This results in the necessity to not only base components on technical aspects, but also to include economical aspects in their design. This paper presents a framework that links technical and economical aspects to the management of computational resources. Economic enhancements like dynamic pricing and client classification are introduced based on a technical resource management environment and positioned within this resulting in a proposed architecture for an Economically Enhanced Resource Manager (EERM). The introduced approach is evaluated considering various economic design criteria and example scenarios.

Cloud computing is strongly based on virtualization, allowing applications to be multiplexed onto a physical resource while isolated from other applications sharing that physical resource. This technology simplifies the management of e-Infrastructures, but also requires additional effort if users are to benefit from it. Cloud computing must hide its underlying complexity from users: the key is to provide users with a simple but functional interface for accessing IT resources "as a service", while allowing providers to build costeffective self-managed systems for transparently managing these resources. System developers should be also supported with simple tools that allow them to exploit the facilities of cloud infrastructures.

El contingut d’aquest projecte es basa en el redisseny d’un dispositiu per al transport de un georadar. Es parteix d’un dispositiu ja dissenyat i s’estudia les mancances tècniques i de confort d’aquest. Seguidament es planteja un nou model que aconsegueixi resoldre aquestes deficiències de la millor manera possible. Aquest nou disseny quedarà completament dimensionat mitjançant els càlculs estructurals pertinents i el material que composa cada una de les peces que formen el dispositiu de transport. S’han de tenir en compte les propietats físiques dels materials utilitzats, ja que aquestes poden influir a l’hora de prendre mostres amb el georadar i produir interferències que donguin una lectura errònia de la mesura que s’ha pres. Finalment es calcularà un pressupost del que valdrà construir el prototip que s’ha definit en aquest projecte.

Nowadays, service providers in the Cloud offer complex services ready to be used as it was a commodity like water or electricity to their customers. A key technology for this approach is virtualization which facilitates provider's management and provides on-demand virtual environments, which are isolated and consolidated in order to achieve a better utilization of the provider's resources. However, dealing with some virtualization capabilities, such as the creation of virtual environments, implies an effort for the user in order to take benefit from them. In order to avoid this problem, we are contributing the research community with the EMOTIVE (Elastic Management of Tasks in Virtualized Environments) middleware, which allows executing tasks and providing virtualized environments to the users without any extra effort in an efficient way. This is a virtualized environment manager which aims to provide virtual machines that fulfils with the user requirements in terms of software and system capabilities. Furthermore, it supports fine-grained local resource management and provides facilities for developing scheduling policies such as migration and checkpointing.

The trustworthiness of commodity providers is a key issue to motivate customers to participate in a market. Several Grid Market frameworks are being developed and they are not an exception in the need of demonstrate their trustworthiness to clients. This paper proposes a simple reputation mechanism for auctions within Grid Markets, which is easy to embed in old Grid solutions that do not provide reputation yet. Effectiveness of this mechanism is proved through simulation in different market scenarios, by showing the direct correlation between reputation and revenue of Grid service providers.

The amphioxus Hox cluster is often viewed as “archetypal” for the chordate lineage. Here we present a descriptive account of the 448kb region spanning the Hox cluster of the amphioxus Branchiostoma floridae from Hox14 to Hox1.We provide complete coding sequences of all 14 previously described amphioxus sequences and describe a detailed analysis of the conserved non-coding regulatory sequence elements. We find that the posterior part of the Hox cluster is so highly derived that even the complete genomic sequence is insufficient to decide whether the posterior Hox genes arose by independent duplications or whether they are true orthologs of the corresponding gnathostome paralog groups. In contrast, the anterior region is much better conserved. The amphioxus Hox cluster strongly excludes repetitive elements with the exception of two repeat islands in the posterior region. Repeat exclusion is also observed in gnathostomes, but not protostome Hox clusters. We thus hypothesize that the much shorter vertebrate Hox clusters are the result of extensive resolution of the redundancy of regulatory DNA following the genome duplications rather than the consequence of a selection pressure to remove non-functional sequence from the cluster.

The Open Grid Services Architecture (OGSA) defines a new vision of the Grid based on the use of Web Services (Grid Services). The standard interfaces, behaviors and schemes that are consistent with the OGSA specification are defined by the Open Grid Service Infrastructure (OGSI). Grid Services, as an extension of the Web Services, run on top of rich execution frameworks that make them accessible and interoperable with other applications. Two examples of these frameworks are Sun’s J2EE platform and Microsoft’s .NET. The Globus Project implements the OGSI Specification for the J2EE framework in the Globus Toolkit. As any J2EE application, the performance of the Globus Toolkit is constrained by the performance obtained by the J2EE execution stack This performance can be influenced by many points of the execution stack: operating system, JVM, middleware or the same grid service, without forgetting the processing overheads related to the parsing of the communication protocols. In the scope of this chapter, all this levels together will be referred to as the grid middleware. In order to avoid the grid middleware to become a performance bottleneck for a distributed grid-enabled application, grid nodes have to be tuned for an efficient execution of I/O intensive applications because they can receive a high volume of requests every second and have to deal with a big amount of invocations, message parsing operations and a continuous task of marshaling and unmarshalling service parameters. All the parameters of the system affecting these operations have to be tuned according with the expected system load intensity. A Grid node is connected to to other nodes through a network connection which is also a decisive factor to obtain a high performance for a grid application. If the inter-node data transmission time overlaps completely the processing time for a computational task, the benefits of the grid architecture will be lost. Additionally, in many situations the content exchanged between grid nodes can be considered confidential and should be protected from curious sights. But the cost of data encryption/decryption can be an important performance weak that must be taken into account. In this chapter we will study the process of receiving and executing a Grid job from the perspective of the underlying levels existing below the Grid application. We will analyze the different performance parameters that can influence in the performance of the Grid middleware and will show the general schema of tasks involved in the service of an execution request.

Els objectius d'aquest treball són donar una perspectiva general de la metodologia de les mesures continues de forma, que permeten una descripció senzilla, però acurada, de l'entorn de coordinació en compostos de metalls de transició. S'introduirà una nova eina associada a la metodologia de les mesures de forma pel seguiment d'estructures que es troben en camins d'interconversió entre poliedres. Les mesures de forma seran emprades per analitzar 1'esteroquímica de compostos organometàl·lics, comparant aquests compostos i els seus lligands típics amb els anàlegs de química de coordinació. S'estudiarà l'estereoquímica de compostos tetracoordinats i pentacoordinats en funció de la configuració electrònica del metall i de les restriccions estereoquímiques imposades per lligands amb diferent denticitat. Pels compostos tetracoordinats, es farà un estudi de les corbes d'energia per totes les configuracions electròniques i pels diferents estats de spin, per correlacionar la distribució de les estructures experimentals amb les geometries i estats de spin predits a nivell teòric. Es mostrarà com es poden obtenir un conjunt de regles senzilles per la predicció de l'entom de coordinació en compostos tetracoordinats en funció de l'estructura electrònica del metall, i quins són els factors que poden modificar l'estat de spin del metall. Finalment, i donada la relació intima que hi ha entre estructura i propietats, es farà un estudi de la correlació entre el paràmetre de desdoblarnent a camp zero, calculat teòricament, i l'entom de coordinació del metall.

In this paper we show how modeling and simulating a complex system such as a web-server can help to evaluate di erent metrics and proposals to improve the performance without necessity of using a real system. Many times the system is unavailable or requires spending time and resources to generate results. With simulation and concretely with a coarse-grain simulation as we propose can solve with great success this problem. In this article we have been able to simulate the metric and behaviour of a web server with SSL security, the ellapsed time required by the simulation on a desktop machine is only 1/10 of real time. We have also been able to measure, for example,the performance enhancements with 8 CPUs without having an available machine of similar features.

El disseny del llenguatge Java, que inclou aspectes importants com són la seva portabilitat i neutralitat envers l'arquitectura, les seves capacitats multithreading, la seva familiaritat (degut a la seva semblança amb C/C++), la seva robustesa, les seves capacitats en seguretat i la seva naturalesa distribuïda, fan que sigui un llenguatge potencialment interessant per ser utilitzat en entorns paral·lels com són els entorns de computació d'altes prestacions (HPC), on les aplicacions poden treure profit del suport que ofereix Java a l'execució multithreaded per realitzar càlculs en paral·lel, o en entorns e-business, on els servidors Java multithreaded (que segueixen l'especificació J2EE) poden treure profit de les capacitats multithreading de Java per atendre de manera concurrent un gran nombre de peticions.No obstant, l'ús de Java per la programació paral·lela ha d'enfrontar-se a una sèrie de problemes que fàcilment poden neutralitzar el guany obtingut amb l'execució en paral·lel. El primer problema és el gran overhead provocat pel suport de threads de la JVM quan s'utilitzen threads per executar feina de gra fi, quan es crea un gran nombre de threads per suportar l'execució d'una aplicació o quan els threads interaccionen estretament mitjançant mecanismes de sincronització. El segon problema és la degradació en el rendiment produïda quan aquestes aplicacions multithreaded s'executen en sistemes paral·lels multiprogramats. La principal causa d'aquest problemes és la manca de comunicació entre l'entorn d'execució i les aplicacions, la qual pot induir a les aplicacions a fer un ús descoordinat dels recursos disponibles.Aquesta tesi contribueix amb la definició d'un entorn per analitzar i comprendre el comportament de les aplicacions Java multithreaded. La contribució principal d'aquest entorn és que la informació de tots els nivells involucrats en l'execució (aplicació, servidor d'aplicacions, JVM i sistema operatiu) està correlada. Aquest fet és molt important per entendre com aquest tipus d'aplicacions es comporten quan s'executen en entorns que inclouen servidors i màquines virtuals, donat que l'origen dels problemes de rendiment es pot trobar en qualsevol d'aquests nivells o en la seva interacció.Addicionalment, i basat en el coneixement adquirit mitjançant l'entorn d'anàlisis proposat, aquesta tesi contribueix amb mecanismes i polítiques de planificació orientats cap a l'execució eficient d'aplicacions Java multithreaded en sistemes multiprocessador considerant les interaccions i la coordinació dels mecanismes i les polítiques de planificació en els diferents nivells involucrats en l'execució. La idea bàsica consisteix en permetre la cooperació entre les aplicacions i l'entorn d'execució en la gestió de recursos establint una comunicació bi-direccional entre les aplicacions i el sistema. Per una banda, les aplicacions demanen a l'entorn d'execució la quantitat de recursos que necessiten. Per altra banda, l'entorn d'execució pot ser inquirit en qualsevol moment per les aplicacions ser informades sobre la seva assignació de recursos. Aquesta tesi proposa que les aplicacions utilitzin la informació proporcionada per l'entorn d'execució per adaptar el seu comportament a la quantitat de recursos que tenen assignats (aplicacions auto-adaptables). Aquesta adaptació s'assoleix en aquesta tesi per entorns HPC per mitjà de la mal·leabilitat de les aplicacions, i per entorns e-business amb una proposta de control de congestió que fa control d'admissió basat en la diferenciació de connexions SSL per prevenir la degradació del rendiment i mantenir la Qualitat de Servei (QoS).Els resultats de l'avaluació demostren que subministrar recursos de manera dinàmica a les aplicacions auto-adaptables en funció de la seva demanda millora el rendiment de les aplicacions Java multithreaded tant en entorns HPC com en entorns e-business. Mentre disposar d'aplicacions auto-adaptables evita la degradació del rendiment, el subministrament dinàmic de recursos permet satisfer els requeriments de les aplicacions en funció de la seva demanda i adaptar-se a la variabilitat de les seves necessitats de recursos. D'aquesta manera s'aconsegueix una millor utilització dels recursos donat que els recursos que no utilitza una aplicació determinada poden ser distribuïts entre les altres aplicacions., The design of the Java language, which includes important aspects such as its portability and architecture neutrality, its multithreading facilities, its familiarity (due to its resemblance with C/C++), its robustness, its security capabilities and its distributed nature, makes it a potentially interesting language to be used in parallel environments such as high performance computing (HPC) environments, where applications can benefit from the Java multithreading support for performing parallel calculations, or e-business environments, where multithreaded Java application servers (i.e. following the J2EE specification) can take profit of Java multithreading facilities to handle concurrently a large number of requests.However, the use of Java for parallel programming has to face a number of problems that can easily offset the gain due to parallel execution. The first problem is the large overhead incurred by the threading support available in the JVM when threads are used to execute fine-grained work, when a large number of threads are created to support the execution of the application or when threads closely interact through synchronization mechanisms. The second problem is the performance degradation occurred when these multithreaded applications are executed in multiprogrammed parallel systems. The main issue that causes these problems is the lack of communication between the execution environment and the applications, which can cause these applications to make an uncoordinated use of the available resources.This thesis contributes with the definition of an environment to analyze and understand the behavior of multithreaded Java applications. The main contribution of this environment is that all levels in the execution (application, application server, JVM and operating system) are correlated. This is very important to understand how this kind of applications behaves when executed on environments that include servers and virtual machines, because the origin of performance problems can reside in any of these levels or in their interaction.In addition, and based on the understanding gathered using the proposed analysis environment, this thesis contributes with scheduling mechanisms and policies oriented towards the efficient execution of multithreaded Java applications on multiprocessor systems considering the interactions and coordination between scheduling mechanisms and policies at the different levels involved in the execution. The basis idea consists of allowing the cooperation between the applications and the execution environment in the resource management by establishing a bi-directional communication path between the applications and the underlying system. On one side, the applications request to the execution environment the amount of resources they need. On the other side, the execution environment can be requested at any time by the applications to inform them about their resource assignments. This thesis proposes that applications use the information provided by the execution environment to adapt their behavior to the amount of resources allocated to them (self-adaptive applications). This adaptation is accomplished in this thesis for HPC environments through the malleability of the applications, and for e-business environments with an overload control approach that performs admission control based on SSL connections differentiation for preventing throughput degradation and maintaining Quality of Service (QoS).The evaluation results demonstrate that providing resources dynamically to self-adaptive applications on demand improves the performance of multithreaded Java applications as in HPC environments as in e-business environments. While having self-adaptive applications avoids performance degradation, dynamic provision of resources allows meeting the requirements of the applications on demand and adapting to their changing resource needs. In this way, better resource utilization is achieved because the resources not used by some application may be distributed among other applications.

Rapid development of e-business services has extended the use of application servers on companies. The Java platform has an important presence on this sector because of its portability and development facilities. Java application servers are becoming a key component in these environments, thus the knowledge of these servers behavior requires the use of new tools to overcome the limitations of existing ones in both offered information and semantics of execution. The natural environment for e-business applications is composed by medium-range parallel servers executing Java based threaded applications. So, understanding threaded Java application servers on parallel environments is the main target of our tool: JIS (Java Instrumentation Suite). This paper describes the design and implementation of JIS and highlights some of the main functionalities. Our initial implementation targets the JVM version 1.3 running Jakarta Tomcat v4.0 on top of a Linux parallel platform with a 2.4.16 kernel.