This thesis explores possibilities for extending the features of honeypot systems to decrease the chance of an attacker discovering that they have compromised a honeypot. It is proposed that by extending the period of time that an attacker spends on a honeypot oblivious to its status, more information relevant to profiling the attacker can be gained. Honeypots are computer systems that are deployed in a way that attackers can easily compromise them. These systems, which contain no production data, are useful both as early warning systems for attacks on production systems, and for studying the tools, techniques, and motives of attackers. Current honeypot systems mitigate the risks of running a honeypot by restricting out-bound traffic in a way that might be obvious to an attacker. The extensions proposed for honeypots will be tested in a controlled laboratory environment.

Today’s Internet content providers primarily use Content Delivery Networks (CDNs) to deliver content to end-users with the aim to enhance their Web access experience. Yet the prevalent commercial CDNs, operating in isolation, often face resource over-provisioning, degraded performance, and Service Level Agreement (SLA) violations, thus incurring high operational costs and limiting the scope and scale of their services. / To move beyond these shortcomings, this thesis sets out to establish the basis for developing advanced and efficient content delivery solutions that are scalable, high performance, and cost-effective. It introduces techniques to enable coordination and cooperation between multiple content delivery services, which is termed as “CDN peering”. In this context, this thesis addresses five key issues ― when to peer (triggering circumstances), how to peer (interaction strategies), whom to peer with (resource discovery), how to manage and enforce operational policies (re-quest-redirection and load sharing), and how to demonstrate peering applicability (measurement study and proof-of-concept implementation). / Thesis Contributions: To support the thesis that the resource over-provisioning and degraded performance problems of existing CDNs can be overcome, thus improving Web access experience of Internet end-users, we have: / - identified the key research challenges and core technical issues for CDN peering, along with a systematic understanding of the CDN space by covering relevant applications, features and implementation techniques, captured in a comprehensive taxonomy of CDNs; / - developed a novel architectural framework, which provides the basis for CDN peering, formed by a set of autonomous CDNs that cooperate through an interconnection mechanism, providing the infrastructure and facilities to virtualize the service of multiple providers; / - devised Quality-of-Service (QoS)-oriented analytical performance models to demonstrate the effects of CDN peering and predict end-user perceived performance, thus facilitating to make concrete QoS performance guarantees for a CDN provider; / - developed enabling techniques, i.e. resource discovery, server selection, and request-redirection algorithms, for CDN peering to achieve service responsiveness. These techniques are exercised to alleviate imbalanced load conditions, while minimizing redirection cost; / - introduced a utility model for CDN peering to measure its content-serving ability by capturing the traffic activities in the system and evaluated through extensive discrete-event simulation analysis. The findings of this study provide incentive for the exploitation of critical parameters for a better CDN peering system design; and / - demonstrated a proof-of-concept implementation of the utility model and an empirical measurement study on MetaCDN, which is a global overlay for Cloud-based content delivery. It is aided with a utility-based redirection scheme to improve the traffic activities in the world-wide distributed network of MetaCDN.

The purpose of this case study was to examine the types of questions a music teacher uses in the classroom and when, and with what frequency, those question types occurred. The questions an experienced general music teacher asked fourth-grade students over the course of five thirty-minute class periods were classified as either procedural/behavioral (36.17%), content (61.97%), or off-topic (1.86%) questions. The content questions were further categorized as either convergent or divergent, as well as whether they were instances of probing, prompting, or redirection. The participant asked an average of approximately 75 questions per class period, and the majority of these (85.84%; n = 200) were convergent. Though previous research has demonstrated the importance of the use of a variety of question types, this knowledge may not have translated to the classroom.

The key challenge in mobile ad-hoc network (MANET) is the design of routing protocol which adapting their behavior to frequency with rapid changes in the network. As we have known, there are two main kinds of routing protocols in MANET: proactive and reactive routing protocol; and in addition, authors [1] proposed to use location information provided by positioning devices such as global positioning systems (GPS) to assist routing. We wonder whether the assumption of all devices in the communication area have the GPS ability is reasonable; furthermore, a GPS-enabled device has its own limitation on working areas; for example, the GPS ability cannot work in the indoor environments. In this paper, (1) we tried to addition the mechanism of probing routing redirection/discovery at routing protocol in AODV. Using overheard node avoid route breaking and select route batter than origin.(2)we tried to use the property of GPS to solve the routing problems in MANET, which like broadcast storm in the route discovery, device power saving and optimal one-hop destination, channel reuse rate, and optimal routing path. According to 802.11 specification, the best way to reach the goal of device power saving is putting device into the sleep mode. In this routing protocol, we let most mobile devices stay in the sleep mode until it sends or receives data or acts as an intermediate node to forward data. Last, we use simulations and implementation to validate the effectiveness of our design.

No description available.

This research addresses the ability of dissipative passive actuators to generate control effects on a passive haptic interface. A haptic display is a human-machine interface that constructs a sensation of touch for the human operator. Applications can be found in various industries, space, medicine and construction etc. A dissipative passive haptic display contains passive actuators that can remove energy from the system by resisting motions in the system. The advantage of a dissipative passive haptic display is better safety compared to an active display. Its disadvantage is the limited control ability from the passive actuators. This research starts with the identification of the control ability and limitations of dissipative passive haptic interfaces. The ability is identified as the steerability, the ability to redirect motions of a manipulator. The force generation analysis of each individual actuator is then selected as an approach to evaluate the steerability. Steerability metrics are defined to evaluate the steerability. Even though non-redundant manipulators dont have desired steerability, optimal steering configurations are found for the best operation. Steerability is improved by redundancy in serial or parallel structures. A theorem is developed to evaluate steerability for redundant manipulators. The influence of system dynamics on their steerabilities is discussed. Previously developed haptic interfaces are evaluated based on their steerabilities. Steerability analysis of three-dimensional haptic interfaces is also given to a limited extent as an extension of the two-dimensional cases. Brakes and clutches are the two types of dissipative passive actuators in this research.

In a commercial Internet environment, the quality of service experienced by a user is critical to competitive advantage and business survivability. The availability and response time of a distributed software service are central components of the overall quality of service provided to users. Traditionally availability is a measure of service down time. Traditionally availability measures the probability that the service will be live and is expressed in terms of failure occurrence and repair or recovery time. Response time is a measure of the time taken from when the service request is made, to when service provision occurs for the user. Deteriorating response time is also a valuable indicator to denial of service attacks which continue to pose a significant threat to service availability. The concept of the service cluster is increasingly being deployed to improve service availability and response time. Cluster processor replication increases service availability. Cluster dispatching of service requests across the replicated cluster processors increases service scalability and therefore response time. This thesis commences with a review of the research and current technology in the area of distributed software service availability. The review aims to identify any deficiencies within that area and propose critical features that mitigate those deficiencies. The three critical features proposed are in relation to user wait time, cluster dispatching, and the trust-based filtering of service requests. The user wait time proposal is that the availability of a distributed service should reflect both liveness probability level and probabalistic user access time of the service. The cluster dispatching proposal is that dispatching processing overhead is a function of the number of Internet Protocol (IP) datagrams/Transport Control Protocol (TCP) segments that are received by the dispatcher in respect of each service request. Consequently the number of IP datagrams/TCP segments should be minimised ideally so that for each incoming service request there is one IP datagram/TCP segment. The trust-based filtering proposal is that the level of trust in respect of each service request should be identified by the service as this is critical in mitigating distributed denial of service attacks - and therefore maximising the availability of the service A conceptual availability model which supports the three critical features within an Internet clustered service environment is then described. The conceptual model proposes an expanded availability definition and then describes the realization of this definition via additional capabilities positioned within the Transport layer of the Internet communication environment. The additional capabilities of this model also facilitate the minimization of cluster dispatcher processing load and the identification by the cluster dispatcher of request trust level. The model is then implemented within the Linux kernel. The implementation involves the addition of several options to the existing TCP specification and also the addition of several functions to the existing Socket API. The implementation is subsequently evaluated in a dispatcher-based clustered service environment.

This report presents several different techniques for diverting RTP streams when using a handheld mobile device. This device is running a version of Minisip as the SIP user agent. An introduction to the SIP protocol is given to provide some background to the reader prior to focusing upon the main goal: redirecting RTP streams. A set of requirements are defined and an RTP media transfer mode is chosen based upon these requirements. The requirements are derived from a study of a Linux cellular phone’s mobile device features and capabilities. Minisip was ported to this platform and a series of tests conducted to evaluate the design decisions made. These tests show that the best method of redirecting RTP media streams is third party call control (3PCC). / Den här rapporten presenterar flera olika teknikerna för att dra RTP strömar när man använder en mobil anordning. Den här anordningen löper en version av Minisip som den SIP användare agent. En introduktion till SIP protokoll är gjord för att ge läsaren någon bakgrund på focusen ovanför det huvudsakliga målet : omdirigerande de RTP strömarna. En set av bestämd behov är definierad och en RTP media transfer sätt är vald på grund av de här behoven. Behoven är härrörda från en studie över en Linux mobiltelefon. Minisip var installerad till den här plattformen och en serie av test dirigerad för att utvärdera de gjorda designsbesluten. De här testen visar den bästa metoden för att omdirigera RTP media strömar är den tredje part kalla kontrollen (3PCC).

La généralisation de l’usage de l’Internet, ces dernières années, a été marquée par deux tendances importantes. Nous citerons en premier, l’enthousiasme de plus en plus grand des utilisateurs pour les services médias. Cette tendance est particulièrement accentuée par l’avènement des contenus générés par les utilisateurs qui amènent dans les catalogues des fournisseurs de services un choix illimité de contenus. L’autre tendance est la diversification et l’hétérogénéité en ressources des terminaux et réseaux d’accès. Seule la valeur du service lui-même compte aujourd’hui pour les utilisateurs et non le moyen d’y accéder. Cependant, offrir aux utilisateurs un accès ubiquitaire à de plus en plus de services Internet, impose des exigences très rigoureuses sur l’infrastructure actuelle de l’Internet. En effet, L’évolution de l’Internet devient aujourd’hui une évidence et cette évolution est d’autant plus nécessaire dans un contexte de services multimédias qui sont connus pour leur sensibilité au contexte dans lequel ils sont consommés et pour générer d’énormes quantités de trafic. Dans le cadre de cette thèse, nous nous focalisons sur deux enjeux importants dans l’évolution de l’Internet. A savoir, faciliter le déploiement de services médias personnalisés et adaptatifs et améliorer les plateformes de distribution de ces derniers afin de permettre leur passage à l’échelle tout en gardant la qualité de service à un niveau satisfaisant pour les utilisateurs finaux. Afin de permettre ceci, nous introduisons en premier, une nouvelle architecture multi environnements et multi couches permettant un environnement collaboratif pour le partage et la consommation des services médias dans un cadre des réseaux média du futur. Puis, nous proposons deux contributions majeures que nous déployons sur la couche virtuelle formés par les Home-Boxes (passerelles résidentielles évoluées) introduite dans l’architecture précédente. Dans notre première contribution, nous proposons un environnement permettant le déploiement à grande échelle de services sensibles au contexte. Deux approches ont été considérées dans la modélisation et la gestion du contexte. La première approche est basée sur les langages de balisage afin de permettre un traitement du contexte plus léger et par conséquent des temps de réponse très petits. La seconde approche, quant à elle est basée sur les ontologies et les règles afin de permettre plus d’expressivité et un meilleur partage et réutilisation des informations de contexte. Les ontologies étant connues pour leur complexité, le but de cette proposition et de prouver la faisabilité d’une telle approche dans un contexte de services multimédias par des moyen de distribution de la gestion du contexte. Concernant notre deuxième contribution, l’idée et de tirer profit des ressources (disque et connectivité) des Home-Boxes déjà déployées, afin d’améliorer les plateformes de distribution des services médias et d’améliorer ainsi le passage à l’échelle, la performance et la fiabilité de ces derniers et ce, à moindre coût. Pour cela, nous proposons deux solutions pour deux problèmes communément traités dans la réplication des contenus : (1) la redirection de requêtes pour laquelle nous proposons un algorithme de sélection à deux niveaux de filtrage, un premier filtrage basé sur les règles afin de personnaliser les services en fonction du contexte de leur consommation suivi d’un filtrage basé sur des métriques réseaux (charges des serveurs et délais entre les serveurs et les clients) ; et (2) le placement et la distribution des contenus sur les caches pour lesquels on a proposé une stratégie de mise en cache online, basée sur la popularité des contenus. / Users’ willingness to consume media services along with the compelling proliferation of mobile devices interconnected via multiple wired and wireless networking technologies place high requirements on the Future Internet. It is a common belief today that Internet should evolve towards providing end users with ubiquitous and high quality media services and this, in a scalable, reliable, efficient and interoperable way. However, enabling such a seamless media delivery raises a number of challenges. On one hand, services should be more context-aware to enable their delivery to a large and disparate computational context. On another hand, current Internet media delivery infrastructures need to scale in order to meet the continuously growing number of users while keeping quality at a satisfying level. In this context, we introduce a novel architecture, enabling a novel collaborative framework for sharing and consuming Media Services within Future Internet (FI). The introduced architecture comprises a number of environments and layers aiming to improve today’s media delivery networks and systems towards a better user experience. In this thesis, we are particulary interested in enabling context-aware multimedia services provisioning that meets on one hand, the users expectations and needs and on another hand, the exponentially growing users’ demand experienced by these services. Two major and demanding challenges are then faced in this thesis (1) the design of a context-awareness framework that allows adaptive multimedia services provisioning and, (2) the enhancement of the media delivery platform to support large-scale media services. The proposed solutions are built on the newly introduced virtual Home-Box layer in the latter proposed architecture.First, in order to achieve context-awareness, two types of frameworks are proposed based on the two main models for context representation. The markup schemes-based framework aims to achieve light weight context management to ensure performance in term of responsiveness. The second framework uses ontology and rules to model and manage context. The aim is to allow higher formality and better expressiveness and sharing. However, ontology is known to be complex and thus difficult to scale. The aim of our work is then to prove the feasibility of such a solution in the field of multimedia services provisioning when the context management is distributed among the Home-Box layer. Concerning the media services delivery enhancement, the idea is to leverage the participating and already deployed Home-Boxes disk storage and uploading capabilities to achieve service performance, scalability and reliability. Towards this, we have addressed two issues that are commonly induced by the content replication: (1) the server selection for which we have proposed a two-level anycast-based request redirection strategy that consists in a preliminary filtering based on the clients’ contexts and in a second stage provides accurate network distance information, using not only the end-to-end delay metric but also the servers’ load one and, (2) the content placement and replacement in cache for which we have designed an adaptive online popularity-based video caching strategy among the introduced HB overlay.

Com o objetivo de contribuir para a discussão sobre formação contínua de educadores, este estudo analisa as ações de formação empreendidas por uma diretoria de ensino, órgão da estrutura administrativa da Secretaria de Estado de Educação de São Paulo, na implementação do projeto Ensinar e Aprender: Corrigindo o Fluxo do Ciclo II, no período de 2000 a 2003. Para tanto, investiga o papel desempenhado por este órgão na formação contínua de educadores e recorre a um breve retrospecto da história dos órgãos mediadores entre o governo e a escola e da constituição da identidade de seus trabalhadores, na busca dos alicerces de concepções que sobrevivem na atualidade. Os dados empíricos foram coletados por meio de entrevistas semi-estruturadas, intentando captar as perspectivas de sujeitos envolvidos na ação, formadores e formandos, acerca da formação contínua de professores e da atuação, em sua dimensão formadora, da diretoria de ensino. Contrastando as construções individuais, incluindo as da autora, à luz de conceitos sobre formação contínua, desenvolvimento institucional da escola e supervisão escolar, objetiva-se desvelar crenças subjacentes à ação em estudo e apontar dificuldades e possibilidades das diretorias de ensino na viabilização de ações de formação contínua de educadores. Trata-se de uma pesquisa ancorada numa perspectiva qualitativa, que teve como critério para escolha da diretoria de ensino e da escola pesquisadas, suas participações efetivas na implementação do referido projeto, entrevistando-se todos os envolvidos na ação, que ainda encontravam-se em exercício nestes dois órgãos. O estudo evidencia a falta de investimento na estrutura da Secretaria de Estado da Educação, enquanto espaço de formação de professores e aponta permanências de acepções acerca da função executora tanto da diretoria de ensino como da escola, respaldadas na crença de bons modelos de ser professor, prescritos por pessoas ou instituições consideradas detentoras de um saber que as legitima para tal. Constatam-se mudanças na prática docente atribuídas, pelos sujeitos da pesquisa, à participação na ação de formação contínua, mas não se apresentam indícios de sua contribuição para a transformação da escola. Propõe-se, dentro da interinidade das verdades, que as ações de formação da diretoria de ensino direcionem-se para a construção da autonomia da escola e do professor, a partir da priorização da determinação partilhada de suas necessidades, requerendo-se, a vista das evidências apontadas, investimentos no desenvolvimento profissional dos trabalhadores das diretorias de ensino. / Having the aim to make contributions for the discussion about educators continuous development, this research analyses the developmental actions done by a Teaching Directory Body an administrative office belonging to the Education State Board of São Paulo, during the implementation of the Teaching and Learning Project: Redirecting the flow of II Cycle, from 2000 to 2003. In order to fulfill this aim, it investigates the role performed by the Body in educators continuous development actions and resorts to a brief historical retrospective about the mediating offices between the state government and school and to the identity construction of the school workers, in search for the foundation of concepts which are still present nowadays. The empirical data were collected in semi-structured interviews, with the objective of capturing the perspectives of the subjects involved in the action trainers and trainees, about the educators continuous development and about the performance in its developmental aspect, of the Teaching Directory Body. Contrasting the individual constructions, including those of the author, in the light of concepts about continuous development, school institutional development and school supervision, the aim is to unclose beliefs underpinning the action studied and to point at difficulties and possibilities of Teaching Directory Bodies in the implementation process of educators continuous development actions. It is a qualitative research, which had as a criteria for choosing both Teaching Directory Bodies and the school itself, their participation in the implementation of the studied project which was assessed by interviewing all the people involved in the action who were still at work in both institutions. The study shows the lack of investment in the Education State Board structure, both as a developmental locus for teachers and it points at permanent concepts of the working role of both the Teaching Directory Body as well as the school, supported by the belief on right models of what to be a good teacher is, prescribed by people or institutions which have legitimized knowledge. We observe changes in the teaching practice, laid by the research subjects, to the participation in the continuous development action, but we didnt observe any evidence of their contribution to the school transformation. The proposal, regarded provisional truths, is that the developmental actions of the Teaching Directory Body direct themselves towards the construction of school and teacher autonomy, from the process of establishing a priority related to a shared determination of their needs. In order to do this, it is required- based on the observed evidences, investments in the professional development of workers at the Teaching Directory Bodies.