934 resultados para distributed denial-of-service attack


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David Tittensor offers a groundbreaking new perspective on the Gülen movement, a Turkish Muslim educational activist network that emerged in the 1960s and has grown into a global empire with an estimated worth of $25 billion. Named after its leader Fethullah Gülen, the movement has established more than 1,000 secular educational institutions in over 140 countries, aiming to provide holistic education that incorporates both spirituality and the secular sciences.

Despite the movement's success, little is known about how its schools are run, or how Islam is operationalized. Drawing on thirteen months of ethnographic fieldwork in Turkey, Tittensor explores the movement's ideo-theology and how it is practiced in the schools. His interviews with both teachers and graduates from Africa, Indonesia, Central Asia, and Turkey show that the movement is a missionary organization, but of a singular kind: its goal is not simply widespread religious conversion, but a quest to recoup those Muslims who have apparently lost their way and to show non-Muslims that Muslims can embrace modernity and integrate into the wider community. Tittensor also examines the movement's operational side and shows how the schools represent an example of Mohammad Yunus's social business model: a business with a social cause at its heart.

The House of Service is an insightful exploration of one of the world's largest transnational Muslim associations, and will be invaluable for those seeking to understand how Islam will be perceived and practiced in the future.

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 The major contributions presented in this thesis are twofold. Firstly, it presents the research towards a unique services-based Hydrocarbon Exploration and Discovery Model that demonstrates the feasibility of using advanced ICT technologies in the reproduction of stages involved in an oil and gas discovery, processing and analysis process. Secondly, the research demonstrated a solution of the problems in providing agreed level of quality of service (QoS) and formalizing of appropriate Service Level Agreements (SLA) within such complex environment where different services within the model can be delivered by a variety of service providers

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PURPOSE: To determine patient, staff and community volunteer opinions and experiences of point of service feedback (POSF) in an inpatient rehabilitation facility. METHOD: Participants were recruited by purposeful sampling. Two researchers conducted in-depth semi-scripted interviews with patients, staff or volunteers until no new issues emerged. Manually transcribed interview data underwent thematic analysis that grouped information into categories of related information. RESULTS: Twenty patients, 26 staff from 10 different professional groups, and 2 community volunteers were interviewed. Patient and volunteer data were grouped into five main categories: patients wanted their voice heard and acted on; patients could be positively and negatively affected by POSF; patients could be reluctant to evaluate staff; patients preferred POSF to post-discharge mailed questionnaires; and patients' feedback was influenced by the data collector. Staff wanted: feedback to help them improve the patient experience; and feedback that was trustworthy, usable and used. Staff believed that the feedback-collector influenced patients' feedback and affected how feedback could be used. CONCLUSIONS: Patients, staff and community volunteers identified issues that determine the appropriateness and usefulness of POSF. Policy and practise should address the preferences, needs and experiences of health service users and providers so that POSF produces maximum benefits for both patients and health services. Implications for Rehabilitation POSF can enhance patients' experiences of inpatient rehabilitation by providing a mechanism to be heard and communicating that patients are valued; care must be exercised with patients who find giving feedback stressful. Collecting POSF is most beneficial when coupled with methods to efficiently and effectively respond to feedback. POSF requires interpretation in light of its limitations including patients' ability to accurately and unreservedly communicate their experiences. Who collects POSF requires careful consideration; community volunteers have both advantages and disadvantages.

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Insider threat has become a serious information security issues within organizations. In this paper, we analyze the problem of insider threats with emphases on the Cloud computing platform. Security is one of the major anxieties when planning to adopt the Cloud. This paper will contribute towards the conception of mitigation strategies that can be relied on to solve the malicious insider threats. While Cloud computing relieves organizations from the burden of the data management and storage costs, security in general and the malicious insider threats in particular is the main concern in cloud environments. We will analyses the existing mitigation strategies to reduce malicious insiders threats in Cloud computing.

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Cognitive radio improves spectrum efficiency and mitigates spectrum scarcity by allowing cognitive users to opportunistically access idle chunks of the spectrum owned by licensed users. In long-term spectrum leasing markets, secondary network operators make a decision about how much spectrum is optimal to fulfill their users' data transmission requirements. We study this optimization problem in multiple channel scenarios. Under the constrains of expected user admission rate and quality of service, we model the secondary network into a dynamic data transportation system. In this system, the spectrum accesses of both primary users and secondary users are in accordance with stochastic processes, respectively. The main metrics of quality of service we are concerned with include user admission rate, average transmission delay and stability of the delay. To quantify the relationship between spectrum provisioning and quality of service, we propose an approximate analytical model. We use the model to estimate the lower and upper bounds of the optimal amount of the spectrum. The distance between the bounds is relatively narrow. In addition, we design a simple algorithm to compute the optimum by using the bounds. We conduct numerical simulations on a slotted multiple channel dynamic spectrum access network model. Simulation results demonstrate the preciseness of the proposed model. Our work sheds light on the design of game and auction based dynamic spectrum sharing mechanisms in cognitive radio networks.

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Word-of-mouth is a powerful force in today’s marketplace. However, few researchers
examine how the dimensions of SERVQUAL relate to positive word-of-mouth, particularly in
the Chinese market. This study attempts to fill this gap. The context is Chinese
telecommunication market. A survey was conducted with a sample of 241 respondents. The
results showed that Reliability and Assurance encouraged more positive word-of-mouth
intention, while Tangibles, Responsiveness, and Empathy did not have any significant effect
on one’s word-of-mouth. These findings have useful implications to international service
companies, particularly those operating in a Chinese environment, by identifying factors that
are salient to the generation of positive word-of-mouth.

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OBJECTIVE: Point of service feedback (POSF) enables patients to give health services feedback about their experiences during or immediately after care. Despite the increasing use of POSF, little is known regarding patients' and staffs' opinions of this practice and whether they consider it acceptable or useful. The study aimed to determine patient and staff opinions regarding POSF. DESIGN: A cross-sectional survey. SETTING: Acute and subacute healthcare facilities. PARTICIPANTS: Two hundred and forty-seven patients and 221 staff. RESULTS: Participants indicated that patients should be invited to evaluate health services when they are in hospital or subacute care and improving services was the most important reason for doing so. Staff indicated that:• collecting patients' feedback during their stay was an important part of providing care and not an interruption to it (n = 187 of 221, 85%).• collecting patients' feedback was best done with a variety of methods; talking directly with patients during their stay was the preferred option (n = 161 of 219, 74%).More patients preferred to:• give feedback during their stay (51%) than after discharge from care (15%).• give feedback by talking with someone (45%) than completing a questionnaire (31%).Some patients (14%) were concerned about reprisal from staff if they gave negative feedback. CONCLUSIONS: POSF can be acceptable and useful for evaluating health services and should be incorporated into a person-centred approach that allows patients to choose from a variety of feedback options both during and after their stay. To be most useful, feedback should be incorporated into a quality improvement system.

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Security is a major challenge in Opportunistic Networks because of its characteristics, such as open medium, dynamic topology, no centralized management and absent clear lines of defense. A packet dropping attack is one of the major security threats in OppNets since neither source nodes nor destination nodes have the knowledge of where or when the packet will be dropped. In this paper, we present a malicious nodes detection mechanism against a special type of packet dropping attack where the malicious node drops one or more packets and then injects new fake packets instead. Our novel detection and traceback mechanism is very powerful and has very high accuracy. Each node can detect and then traceback the malicious nodes based on a solid and powerful idea that is, Merkle tree hashing technique. In our defense techniques we have two stages. The first stage is to detect the attack, and the second stage is to find the malicious nodes. We have compared our approach with the acknowledgement based mechanisms and the networks coding based mechanism which are well known approaches in the literature. Simulation results show this robust mechanism achieves a very high accuracy and detection rate.

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The work described in this thesis aims to support the distributed design of integrated systems and considers specifically the need for collaborative interaction among designers. Particular emphasis was given to issues which were only marginally considered in previous approaches, such as the abstraction of the distribution of design automation resources over the network, the possibility of both synchronous and asynchronous interaction among designers and the support for extensible design data models. Such issues demand a rather complex software infrastructure, as possible solutions must encompass a wide range of software modules: from user interfaces to middleware to databases. To build such structure, several engineering techniques were employed and some original solutions were devised. The core of the proposed solution is based in the joint application of two homonymic technologies: CAD Frameworks and object-oriented frameworks. The former concept was coined in the late 80's within the electronic design automation community and comprehends a layered software environment which aims to support CAD tool developers, CAD administrators/integrators and designers. The latter, developed during the last decade by the software engineering community, is a software architecture model to build extensible and reusable object-oriented software subsystems. In this work, we proposed to create an object-oriented framework which includes extensible sets of design data primitives and design tool building blocks. Such object-oriented framework is included within a CAD Framework, where it plays important roles on typical CAD Framework services such as design data representation and management, versioning, user interfaces, design management and tool integration. The implemented CAD Framework - named Cave2 - followed the classical layered architecture presented by Barnes, Harrison, Newton and Spickelmier, but the possibilities granted by the use of the object-oriented framework foundations allowed a series of improvements which were not available in previous approaches: - object-oriented frameworks are extensible by design, thus this should be also true regarding the implemented sets of design data primitives and design tool building blocks. This means that both the design representation model and the software modules dealing with it can be upgraded or adapted to a particular design methodology, and that such extensions and adaptations will still inherit the architectural and functional aspects implemented in the object-oriented framework foundation; - the design semantics and the design visualization are both part of the object-oriented framework, but in clearly separated models. This allows for different visualization strategies for a given design data set, which gives collaborating parties the flexibility to choose individual visualization settings; - the control of the consistency between semantics and visualization - a particularly important issue in a design environment with multiple views of a single design - is also included in the foundations of the object-oriented framework. Such mechanism is generic enough to be also used by further extensions of the design data model, as it is based on the inversion of control between view and semantics. The view receives the user input and propagates such event to the semantic model, which evaluates if a state change is possible. If positive, it triggers the change of state of both semantics and view. Our approach took advantage of such inversion of control and included an layer between semantics and view to take into account the possibility of multi-view consistency; - to optimize the consistency control mechanism between views and semantics, we propose an event-based approach that captures each discrete interaction of a designer with his/her respective design views. The information about each interaction is encapsulated inside an event object, which may be propagated to the design semantics - and thus to other possible views - according to the consistency policy which is being used. Furthermore, the use of event pools allows for a late synchronization between view and semantics in case of unavailability of a network connection between them; - the use of proxy objects raised significantly the abstraction of the integration of design automation resources, as either remote or local tools and services are accessed through method calls in a local object. The connection to remote tools and services using a look-up protocol also abstracted completely the network location of such resources, allowing for resource addition and removal during runtime; - the implemented CAD Framework is completely based on Java technology, so it relies on the Java Virtual Machine as the layer which grants the independence between the CAD Framework and the operating system. All such improvements contributed to a higher abstraction on the distribution of design automation resources and also introduced a new paradigm for the remote interaction between designers. The resulting CAD Framework is able to support fine-grained collaboration based on events, so every single design update performed by a designer can be propagated to the rest of the design team regardless of their location in the distributed environment. This can increase the group awareness and allow a richer transfer of experiences among them, improving significantly the collaboration potential when compared to previously proposed file-based or record-based approaches. Three different case studies were conducted to validate the proposed approach, each one focusing one a subset of the contributions of this thesis. The first one uses the proxy-based resource distribution architecture to implement a prototyping platform using reconfigurable hardware modules. The second one extends the foundations of the implemented object-oriented framework to support interface-based design. Such extensions - design representation primitives and tool blocks - are used to implement a design entry tool named IBlaDe, which allows the collaborative creation of functional and structural models of integrated systems. The third case study regards the possibility of integration of multimedia metadata to the design data model. Such possibility is explored in the frame of an online educational and training platform.

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Nowadays, networks must support applications such as: distance learning, electronic commerce, access to Internet, Intranets and Extranets, voice over IP (Internet Protocol) and many others. These new applications, employing data, voice, and video traffic, require high bandwidth and Quality of Service (QoS). The ATM (Asynchronous Transfer Mode) technology, together with dynamic resource allocation methods, offers network connections that guarantee QoS parameters, such as minimum losses and delays. This paper presents a system that uses Network Management Functions together with dynamic resource allocation for provision of the end-to-end QoS parameters for rt-VBR connections.