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1
Danielsson, Oscar. "Adaptive AR-system : Adapting manufacturing instructions to worker needs." Thesis, Högskolan i Skövde, Institutionen för ingenjörsvetenskap, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:his:diva-11631.
Testo completoAbstract (sommario):
This thesis looks at Augmented Reality (AR) and Expert Systems (ES) and how concepts from these techniques can be used to make instructions simpler for workers in the manufacturing industry. The experiment performed is based on a case study of “Block 9-11” at Volvo GTO in Skövde. A comparative study between the developed AR-system and the currently used instruction format has been made. For practical reasons the tasks and instructions were modified from the original. The results showed a similar time usage for the two systems but with a large amount of steps missed in the control group as well as a lower subjective usability-score from the testers, showing an advantage for the AR-system. In future work the plan is to further develop the adaptability-aspect, an aspect that didn’t give clear results in this study.<br>YOU2
2
Khan, Javed Arif. "A visual adaptive authoring framework for adaptive hypermedia." Thesis, University of Warwick, 2018. http://wrap.warwick.ac.uk/111668/.
Testo completoAbstract (sommario):
In a linear hypermedia system, all users are offered a standard series of hyperlinks. Adaptive Hypermedia (AH) tailors what the user sees to the user's goals, abilities, interests, knowledge and preferences. Adaptive Hypermedia is said to be the answer to the 'lost in hyperspace' phenomenon, where the user has too many hyperlinks to choose from, and has little knowledge to select the most appropriate hyperlink. AH offers a selection of links and content that is most appropriate to the current user. In an Adaptive Educational Hypermedia (AEH) course, a student's learning experiences can be personalised using a User Model (UM), which could include information such as the student's knowledge level, preferences and culture. Beside these basic components, a Goal Model (GM) can represent the goal the users should meet and a Domain Model (DM) would represent the knowledge domain. Adaptive strategies are sets of adaptive rules that can be applied to these models, to allow the personalisation of the course for students, according to their needs. From the many interacting elements, it is clear that the authoring process is a bottleneck in the adaptive course creation, which needs to be improved in terms of interoperability, usability and reuse of the adaptive behaviour (strategies). Authoring of Adaptive Hypermedia is considered to be difficult and time consuming. There is great scope for improving authoring tools in Adaptive Educational Hypermedia system, to aid already burdened authors to create adaptive courses easily. Adaptation specifications are very useful in creating adaptive behaviours, to support the needs of a group of learners. Authors often lack the time or the skills needed to create new adaptation specifications from scratch. Creating an adaptation specification requires the author to know and remember the programming language syntax, which places a knowledge barrier for the author. LAG is a complete and useful programming language, which, however, is considered too complex for authors to deal with directly. This thesis thus proposes a visual framework (LAGBlocks) for the LAG adaptation language and an authoring tool (VASE) to utilise the proposed visual framework, to create adaptive specifications, by manipulating visual elements. It is shown that the VASE authoring tool along with the visual framework enables authors to create adaptive specifications with ease and assist authors in creating adaptive specifications which promote the "separation of concern". The VASE authoring tool offers code completeness, correctness at design time, and also allows for adaptive strategies to be used within other tools for adaptive hypermedia. The goal is thus to make adaptive specifications easier, to create and to share for authors with little or no programming knowledge and experience. This thesis looks at three aspects of authoring in adaptive educational hypermedia systems. The first aspect of the thesis is concerned with problems faced by the author of an adaptive hypermedia system; the second aspect is concerned with describing the findings gathered from investigating the previously developed authoring tools; and the final aspect of the thesis is concerned with the proposal, the implementation and the evaluation of a new authoring tool that improves the authoring process for authors with different knowledge, background and experience. The purpose of the new tool, VASE, is to enable authors to create adaptive strategies in a puzzle-building manner; moreover, the created adaptive strategies could be used within (are compatible with) other systems in adaptive hypermedia, which use the LAG programming language.
3
Fjær, Dag Henrik, and Kjeld Karim Berg Massali. "Adaptive Robotics." Thesis, Norwegian University of Science and Technology, Department of Computer and Information Science, 2009. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-9861.
Testo completoAbstract (sommario):
<p>This report explores continuous-time recurrent neural networks (CTRNNs) and their utility in the field of adaptive robotics. The networks herein are evolved in a simulated environment and evaluated on a real robot. The evolved CTRNNs are presented with simple cognitive tasks and the results are analyzed in detail.</p>
4
Grundtman, Per. "Adaptive Learning." Thesis, Luleå tekniska universitet, Institutionen för system- och rymdteknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-61648.
Testo completoAbstract (sommario):
The purpose of this project is to develop a novel proof-of-concept system in attempt to measure affective states during learning-tasks and investigate whether machine learning models trained with this data has the potential to enhance the learning experience for an individual. By considering biometric signals from a user during a learning session, the affective states anxiety, engagement and boredom will be classified using different signal transformation methods and finally using machine-learning models from the Weka Java API. Data is collected using an Empatica E4 Wristband which gathers skin- and heart related biometric data which is streamed to an Android application via Bluetooth for processing. Several machine-learning algorithms and features were evaluated for best performance.
5
Lamprecht, Christiaan Johan. "Adaptive security." Thesis, University of Newcastle Upon Tyne, 2012. http://hdl.handle.net/10443/1435.
Testo completoAbstract (sommario):
Automated runtime security adaptation has great potential in providing timely and fine grained security control. In this thesis we study the practical utility of a runtime security-performance trade off for the pervasive Secure Socket Layer (SSL/TLS) protocol. To that end we address a number of research challenges. We develop an Adaptive Security methodology to extend non-adaptive legacy security systems with adaptive features. We also create a design of such an extended system to support the methodology. The design aids in identifying additional key components necessary for the creation of an adaptive security system. We furthermore apply our methodology to the Secure Socket Layer (SSL) protocol to create a design and implementation of a practical Adaptive SSL (ASSL) solution that supports runtime security adaptation in response to cross-cutting environmental concerns. The solution effectively adapts security at runtime, only reducing maximum server load by 15% or more depending on adaptation decision complexity. Next we address the security-performance trade off research challenge. Following our methodology we conduct an offline study of factors affecting server performance when security is adapted. These insights allow for the creation of policies that can trade off security and performance by taking into account the expected future state of the system under adaptation. In so doing we found that client SSL session duration, requested file size and current security algorithm play roles predicting future system state. Notably, performance deviation is smaller when sessions are longer and files are smaller and vice versa. A complete Adaptive Security solution which successfully demonstrates our methodology is implemented with trade-off policies and ASSL as key components. We show that the solution effectively utilises available processing resources to increase security whilst still respecting performance guarantees.
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Wege, Claudia. "Adaptive Eyes." Doctoral thesis, Universitätsbibliothek Chemnitz, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-164158.
Testo completoAbstract (sommario):
Technology pervades our daily living, and is increasingly integrated into the vehicle – directly affecting driving. On the one hand technology such as cell phones provoke driver distraction and inattention, whereas, on the other hand, Advanced Driver Assistance Systems (ADAS) support the driver in the driving task. The question is, can a driver successfully adapt to the ever growing technological advancements? Thus, this thesis aimed at improving safe driver behaviour by understanding the underlying psychological mechanisms that influence behavioural change. Previous research on ADAS and human attention was reviewed in the context of driver behavioural adaptation. Empirical data from multiple data sources such as driving performance data, visual behaviour data, video footage, and subjective data were analyzed to evaluate two ADAS (a brake-capacity forward collision warning system, B-FCW, and a Visual Distraction Alert System, VDA-System). Results from a field operational test (EuroFOT) showed that brake-capacity forward collision warnings lead to immediate attention allocation toward the roadway and drivers hit the brake, yet change their initial response later on by directing their eyes toward the warning source in the instrument cluster. A similar phenomenon of drivers changing initial behaviour was found in a driving simulator study assessing a Visual Distraction Alert System. Analysis showed that a Visual Distraction Alert System successfully assists drivers in redirecting attention to the relevant aspects of the driving task and significantly improves driving performance. The effects are discussed with regard to behavioural adaptation, calibration and system acceptance. Based on these findings a novel assessment for human-machine-interaction (HMI) of ADAS was introduced. Based on the contribution of this thesis and previous best-practices, a holistic safety management model on accident prevention strategies (before, during and after driving) was developed. The DO-IT BEST Feedback Model is a comprehensive feedback strategy including driver feedback at various time scales and therefore is expected to provide an added benefit for distraction and inattention prevention. The central contributions of this work are to advance research in the field of traffic psychology in the context of attention allocation strategies, and to improve the ability to design future safety systems with the human factor in focus. The thesis consists of the introduction of the conducted research, six publications in full text and a comprehensive conclusion of the publications. In brief this thesis intends to improve safe driver behaviour by understanding the underlying psychological mechanisms that influence behavioral change, thereby resulting in more attention allocation to the forward roadway, and improved vehicle control<br>Technologie durchdringt unser tägliches Leben und ist zunehmend integriert in Fahrzeuge – das Resultat sind veränderte Anforderungen an Fahrzeugführer. Einerseits besteht die Gefahr, dass er durch die Bedienung innovativer Technologien (z.B. Mobiltelefone) unachtsam wird und visuell abgelenkt ist, andererseits kann die Nutzung von Fahrerassistenzsystemen die den Fahrer bei der Fahraufgabe unterstützten einen wertvollen Beitrag zur Fahrsicherheit bieten. Die steigende Aktualität beider Problematiken wirft die Frage auf: "Kann der Fahrer sich erfolgreich dem ständig wachsenden technologischen Fortschritt anpassen?" Das Ziel der vorliegenden Arbeit ist der Erkenntnisgewinn zur Verbesserung des Fahrverhaltens indem der Verhaltensänderungen zugrunde liegende psychologische Mechanismen untersucht werden. Eine Vielzahl an Literatur zu Fahrerassistenzsystemen und Aufmerksamkeitsverteilung wurde vor dem Hintergrund von Verhaltensanpassung der Fahrer recherchiert. Daten mehrerer empirischer Quellen, z. B. Fahrverhalten, Blickbewegungen, Videomitschnitte und subjektive Daten dienten zur Datenauswertung zweier Fahrerassistenzsysteme. Im Rahmen einer Feldstudie zeigte sich, dass Bremskapazitäts-Kollisionswarnungen zur sofortigen visuellen Aufmerksamkeitsverteilung zur Fahrbahn und zum Bremsen führen, Fahrer allerdings ihre Reaktion anpassen indem sie zur Warnanzeige im Kombinationsinstrument schauen. Ein anderes Phänomen der Verhaltensanpassung wurde in einer Fahrsimulatorstudie zur Untersuchung eines Ablenkungswarnsystems, das dabei hilft die Blicke von Autofahrern stets auf die Straße zu lenken, gefunden. Diese Ergebnisse weisen nach, dass solch ein System unterstützt achtsamer zu sein und sicherer zu fahren. Die vorliegenden Befunde wurden im Zusammenhang zu Vorbefunden zur Verhaltensanpassung zu Fahrerassistenzsystemen, Fahrerkalibrierung und Akzeptanz von Technik diskutiert. Basierend auf den gewonnenen Erkenntnissen wurde ein neues Vorgehen zur Untersuchung von Mensch- Maschine-Interaktion eingeführt. Aufbauend auf den Resultaten der vorliegenden Arbeit wurde ein ganzheitliches Modell zur Fahrsicherheit und -management, das DO-IT BEST Feedback Modell, entwickelt. Das Modell bezieht sich auf multitemporale Fahrer-Feedbackstrategien und soll somit einen entscheidenen Beitrag zur Verkehrssicherheit und dem Umgang mit Fahrerunaufmerksamkeit leisten. Die zentralen Beiträge dieser Arbeit sind die Gewinnung neuer Erkenntnisse in den Bereichen der Angewandten Psychologie und der Verkehrspsychologie in den Kontexten der Aufmerksamkeitsverteilung und der Verbesserung der Gestaltung von Fahrerassistenzsystemen fokusierend auf den Bediener. Die Dissertation besteht aus einem Einleitungsteil, drei empirischen Beiträgen sowie drei Buchkapiteln und einer abschliessenden Zusammenfassung
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Brunne, Jens [Verfasser], and Ulrike [Akademischer Betreuer] Wallrabe. "Adaptive Axiconspiegel." Freiburg : Universität, 2015. http://d-nb.info/1119805619/34.
Testo completo
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Kshniakin, S. E. "Adaptive camouflage." Thesis, Sumy State University, 2016. http://essuir.sumdu.edu.ua/handle/123456789/45004.
Testo completoAbstract (sommario):
The creation of adaptive camouflage is one of the main tasks for scientists. First of all, this technology is designed to be used in the army. It can push tactics in the battlefield to a higher level. However, all of prototypes that have been already created are still at the stage of testing and development.
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Vollbrecht, Tracy. "Adaptive Aesthetics." Kent State University Honors College / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ksuhonors1525685379561019.
Testo completo
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Maile, Annette. "Adaptive Informationsaufbereitung." [S.l.] : Universität Stuttgart , Fakultät Informatik, 1996. http://www.bsz-bw.de/cgi-bin/xvms.cgi?SWB6783386.
Testo completo
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Silva, Marcelo Pereira da. "Adaptive Remus: replicação de máquinas virtuais Xen com checkpointing adaptável." Universidade do Estado de Santa Catarina, 2015. http://tede.udesc.br/handle/handle/2046.
Testo completoAbstract (sommario):
Made available in DSpace on 2016-12-12T20:22:53Z (GMT). No. of bitstreams: 1
Marcelo Pereira da Silva.pdf: 1790996 bytes, checksum: 8b61245ad63935d86a70520f22eae9bc (MD5)
Previous issue date: 2015-07-03<br>Coordenação de Aperfeiçoamento de Pessoal de Nível Superior<br>With the ever-increasing dependence on computers and networks, many systems are required to be continuously available in order to fulfill their mission. Virtualization technology enables high availability to be offered in a convenient, cost-effective manner: with the encapsulation provided by virtual machines (VMs), entire systems can be replicated transparently in software, obviating the need for expensive fault-tolerant hardware. Remus is a VM replication mechanism for the Xen hypervisor that provides high availability despite crash failures. Replication is performed by checkpointing the VM at fixed intervals. However, there is an antagonism between processing and communication regarding the optimal checkpointing interval: while longer intervals benefit processorintensive applications, shorter intervals favor network-intensive applications. Thus, any chosen interval may not always be suitable for the hosted applications, limiting Remus usage in many scenarios. This work introduces Adaptive Remus, a proposal for adaptive checkpointing in Remus that dynamically adjusts the replication frequency according to the characteristics of running applications. Experimental results indicate that our proposal improves performance for applications that require both processing and communication, without harming applications that use only one type of resource.<br>Com a dependência cada vez maior de computadores e redes, muitos sistemas precisam estar continuamente disponíveis para cumprir sua missão. A tecnologia de virtualização permite prover alta disponibilidade de forma conveniente e a um custo razoável: com o encapsulamento oferecido pelas máquinas virtuais (MVs), sistemas inteiros podem ser replicados em software, de forma transparente, eliminando a necessidade de hardware tolerante a faltas dispendioso. Remus é um mecanismo de replicação de MVs que fornece alta disponibilidade diante de faltas de parada. A replicação é realizada através de checkpointing, seguindo um intervalo fixo de tempo predeterminado. Todavia, existe um antagonismo entre processamento e comunicação em relação ao intervalo ideal entre checkpoints: enquanto intervalos maiores beneficiam aplicações com processamento intensivo, intervalos menores favorecem as aplicações cujo desempenho é dominado pela rede. Logo, o intervalo utilizado nem sempre é o adequado para as características de uso de recursos da aplicação em execução na MV, limitando a aplicabilidade de Remus em determinados cenários. Este trabalho apresenta Adaptive Remus, uma proposta de checkpointing adaptativo para Remus, que ajusta dinamicamente a frequência de replicação de acordo com as características das aplicações em execução. Os resultados indicam que a proposta obtém um melhor desempenho de aplicações que utilizam tanto recursos de processamento como de comunicação, sem prejudicar aplicações que usam apenas um dos tipos de recursos.
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Shah, Ijteba-ul-Hasnain. "Constrained adaptive natural gradient algorithms for adaptive array processing." Thesis, University of Strathclyde, 2011. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=15646.
Testo completo
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Blogh, Jonathan S. "Adaptive modulation and adaptive antenna assisted wireless TDMA/CDMA networks." Thesis, University of Southampton, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.341647.
Testo completo
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Spadoni, Andrea. "Adaptive Brake By Wire: From Human Factors to Adaptive Implementation." Doctoral thesis, Università degli studi di Trento, 2013. https://hdl.handle.net/11572/368607.
Testo completoAbstract (sommario):
The introduction of the Brake By Wire is replacing the traditional mechanical control systems with ECUs and it is raising the need to reproduce feelings of eliminated static mechanical components (i.e. hydraulic fluids, pumps and cylinders). Thanks to electromechanical actuators and human-machine interfaces (i.e. active pedal) it is possible to reproduce such feelings and, therefore, arbitrarily change their features. In this way it will be possible to customize the pedal feelings and the vehicle deceleration needed depending on several factors (i.e. surrounding braking scenario, driver characteristics, race vs day-by-day driving condition). Since braking maneuvers are typically critical and involve the driver, the design and development of brake by wire system must start from the consideration of human factors in order to increase acceptance and braking effectiveness. The objective of this research was to redesign the pedal feelings, making them adaptable to the surrounding. Driver acceptance and braking effectiveness could be highly improved by means of adaptive pedal feelings. The starting points of this research were humans factors in the braking domain. Literature and relevant studies have been taken into consideration to put into evidence human mechanisms and behaviors during braking phases. On such basis, two main results have been found out: braking use cases and pedal feeling curves.
With regard to the pedal feelings curves, 4 different pedal curves which describe both force on brake pedal travel and acceleration on brake pedal travel are designed. The pedal feeling depends on several factors like the pedal travel, the pedal idle travel, the effort, responsiveness, deceleration perceived, ease of balance (i.e. ease of modulation), gradual braking and so on. Regarding braking use cases, they are described by vehicle data as speed, acceleration, angles and relevant rates, engine rpm, gas and brake pedal position/speed and so on. These use cases have been clustered in order to meet the 4 pedal curves.
The research continued on the implementation of a Matlab/Simulink/Stateflow model for the use case recognition. Basing on the vehicle data, the model is able to find out in which use case the vehicle is (parking, low speed maneuvers, emergency, downhill, and so on). Once it finds out the scenario, the model applies the most appropriate pedal feeling curve (both force feedback and deceleration needed). In the end, the model commands an EC brushless motor which is responsible of the changing of static springs force feedback of the pedal. The scenario recognition model has been validated through vehicle data on real road whereas the pedal feeling and relevant motor behaviors have been validate on bench tests.
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Spadoni, Andrea. "Adaptive Brake By Wire: From Human Factors to Adaptive Implementation." Doctoral thesis, University of Trento, 2013. http://eprints-phd.biblio.unitn.it/1319/1/SPADONI_PHD_150dpi.pdf.
Testo completoAbstract (sommario):
The introduction of the Brake By Wire is replacing the traditional mechanical control systems with ECUs and it is raising the need to reproduce feelings of eliminated static mechanical components (i.e. hydraulic fluids, pumps and cylinders). Thanks to electromechanical actuators and human-machine interfaces (i.e. active pedal) it is possible to reproduce such feelings and, therefore, arbitrarily change their features. In this way it will be possible to customize the pedal feelings and the vehicle deceleration needed depending on several factors (i.e. surrounding braking scenario, driver characteristics, race vs day-by-day driving condition). Since braking maneuvers are typically critical and involve the driver, the design and development of brake by wire system must start from the consideration of human factors in order to increase acceptance and braking effectiveness. The objective of this research was to redesign the pedal feelings, making them adaptable to the surrounding. Driver acceptance and braking effectiveness could be highly improved by means of adaptive pedal feelings. The starting points of this research were humans factors in the braking domain. Literature and relevant studies have been taken into consideration to put into evidence human mechanisms and behaviors during braking phases. On such basis, two main results have been found out: braking use cases and pedal feeling curves.
With regard to the pedal feelings curves, 4 different pedal curves which describe both force on brake pedal travel and acceleration on brake pedal travel are designed. The pedal feeling depends on several factors like the pedal travel, the pedal idle travel, the effort, responsiveness, deceleration perceived, ease of balance (i.e. ease of modulation), gradual braking and so on. Regarding braking use cases, they are described by vehicle data as speed, acceleration, angles and relevant rates, engine rpm, gas and brake pedal position/speed and so on. These use cases have been clustered in order to meet the 4 pedal curves.
The research continued on the implementation of a Matlab/Simulink/Stateflow model for the use case recognition. Basing on the vehicle data, the model is able to find out in which use case the vehicle is (parking, low speed maneuvers, emergency, downhill, and so on). Once it finds out the scenario, the model applies the most appropriate pedal feeling curve (both force feedback and deceleration needed). In the end, the model commands an EC brushless motor which is responsible of the changing of static springs force feedback of the pedal. The scenario recognition model has been validated through vehicle data on real road whereas the pedal feeling and relevant motor behaviors have been validate on bench tests.
16
Kvapil, Jiří. "Adaptivní ekvalizace histogramu digitálních obrazů." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2009. http://www.nusl.cz/ntk/nusl-228687.
Testo completoAbstract (sommario):
The diploma thesis is focused on histogram equalization method and his extension by the adaptive boundary. This thesis contains explanations of basic notions on that histogram equalization method was created. Next part is described the human vision and priciples of his imitation. In practical part of this thesis was created software that makes it possible to use methods of adaptive histogram equalization on real images. At the end is showed some results that was reached.
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Takhirov, Naimdjon. "Adaptive personalized eLearning." Thesis, Norwegian University of Science and Technology, Department of Computer and Information Science, 2008. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-8855.
Testo completoAbstract (sommario):
<p>This work has found that mapping prior knowledge and learning style is important for constructing personalized learning offerings for students with different levels of knowledge and learning styles. Prior knowledge assessment and a learning style questionnaire were used to assess the knowledge level and learning style. The proposed model for automatic construction of prior knowledge assessment aims to connect questions in the assessment to speci c course modules in order to identify levels on different modules, because a student may have varying levels of knowledge within different modules. We have also found that it is not easy to map students' prior knowledge with total accuracy. However, this is not required in order to achieve a tailored learning experience; an assessment of prior knowledge can still be used to decide what piece of content should be presented to a particular student. Learning style can be simply de ned as either the way people learn or an individual's preferred way of learning. The VAK learning style inventory has been found suitable to map the learning styles of students, and it is one of few learning style inventories appropriate for online learning assessment. A questionnaire consisting of 16 questions has been used to identify the learning style of students prior to commencement of the course. It is important to consider the number of questions, because the students may feel reluctant to spend too much time on the questionnaire. However, the user evaluation has shown that students willingly answer questions to allow the system to identify their learning styles. This work also presents a comprehensive overview of the state-of-the-art pertaining to learning, learning styles, Learning Management Systems, technologies related to web-based personalization and related standards and speci cations. A brief comparison is also made of various schools that have tried to address personalization of content for web-based learning. Finally, for evaluation purposes, a course on "Designing Relational Databases" was created, and a group of fourteen users evaluated the personalized course.</p>
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Haglund, Leif. "Adaptive Multidimensional Filtering." Doctoral thesis, Linköpings universitet, Bildbehandling, 1991. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-54339.
Testo completoAbstract (sommario):
This thesis contains a presentation and an analysis of adaptive filtering strategies for multidimensional data. The size, shape and orientation of the flter are signal controlled and thus adapted locally to each neighbourhood according to a predefined model. The filter is constructed as a linear weighting of fixed oriented bandpass filters having the same shape but different orientations. The adaptive filtering methods have been tested on both real data and synthesized test data in 2D, e.g. still images, 3D, e.g. image sequences or volumes, with good results. In 4D, e.g. volume sequences, the algorithm is given in its mathematical form. The weighting coefficients are given by the inner products of a tensor representing the local structure of the data and the tensors representing the orientation of the filters. The procedure and lter design in estimating the representation tensor are described. In 2D, the tensor contains information about the local energy, the optimal orientation and a certainty of the orientation. In 3D, the information in the tensor is the energy, the normal to the best ftting local plane and the tangent to the best fitting line, and certainties of these orientations. In the case of time sequences, a quantitative comparison of the proposed method and other (optical flow) algorithms is presented. The estimation of control information is made in different scales. There are two main reasons for this. A single filter has a particular limited pass band which may or may not be tuned to the different sized objects to describe. Second, size or scale is a descriptive feature in its own right. All of this requires the integration of measurements from different scales. The increasing interest in wavelet theory supports the idea that a multiresolution approach is necessary. Hence the resulting adaptive filter will adapt also in size and to different orientations in different scales.
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Yin, Hang. "Adaptive Embedded Systems." Thesis, Mälardalens högskola, Akademin för innovation, design och teknik, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-10590.
Testo completoAbstract (sommario):
Modern embedded systems are evolving in the direction of increased adaptivity and complexity. It is extremely important for a system with limited resource to be adaptive in order to maximize its efficiency of resource usage while guaranteeing a high level of fault tolerance and QoS. This report aims at exploring such a kind of system, i.e. Adaptive Embedded System (AES), which is featured by dynamic reconfiguration at runtime. Based on the investigation and analysis of a variety of case studies related with AES, we proposed the conceptual view and overall architecture of an AES by highlighting its predominant characteristics. We also made an incomplete but detailed summary of the most popular techniques that can be used to realize adaptivity. Those techniques are categorized into dynamic CPU/network resource re-allocation and adaptive fault tolerance. A majority of adaptive applications resort to one or more of those techniques. Besides, there is a separate discussion on dynamic reconfiguration and mode switch for AES. Finally, we classify adaptivity into different modeling problems at a higher abstraction level and build UPPAAL models for two different AESs, a smart phone and an object-tracking robot. Our UPPAAL models provide clear demonstration on how a typical AES works.
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Davidsson, Staffan. "Adaptive Driver Information." Doctoral thesis, Luleå tekniska universitet, Arbetsvetenskap, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-25850.
Testo completoAbstract (sommario):
New societal requirements and functional growth put new demand on future driver information. Simultaneously, new technology and IT capabilities makes it possible to constantly adapt the information given to the driver for different reasons. Therefore, the aim of this thesis was to obtain an improved understanding, strengthen knowledge of the adaptive control of driver information to understand if, for what reason, when and where to use adaptive driver information (ADI). Also some possible new means to support drivers were suggested.The main purpose of driver information is to support the driver in achieving goals such as a safer, more environmentally friendly, more efficient, legal and enjoyable transportation by providing correct information and feedback.ADI can support the driver throughout development of skill and when performing operational, tactical, and strategic level tasks. Also tasks related to setting goals for the driving task and encouraging good driving behaviour can be supported. ADI can, furthermore help drivers to stay within their comfort zone by visualizing risk or certainty, identify and thereafter adapt how a message is communicated to different personalities, maintain the driver’s mental workload within the safe task load area by reducing demand when it is too high, increase mental workload by extra stimulating task during too low a mental demand, and minimize the risk for mismatches between effort and real demand.ADI changes automatically that may cause new and unpredictable issues reducing the purpose of driver information. These may include: mode confusion, function allocation, over and under trust, locus of control issues, skill degeneration and too low/high mental workload. Research has suggested that the most efficient way to reduce these issues is to make the driver and the automation (the agents) get along together and become team players. The team players should share goals, show intention, show limits of performance, state etcetera. However, for cars, a consumer product, in which visual demand is high, an approach can be where information vanishes when agents have become a “team”. This approach may be called “team building”.Research and industrial contributions has been presented. Several examples of how ADI can be carried out have been suggested and some even illustrated.<br><p>Godkänd; 2014; 20141006 (stadav); Nedanstående person kommer att disputera för avläggande av teknologie doktorsexamen. Namn: Staffan Davidsson Ämne: Teknisk Psykologi/Engineering Psychology Avhandling: Adaptive Driver Information Opponent: Docent Forskningsledare Björn Peters, Statens väg- och transportforskningsinstitut, Linköping Ordförande: Professor Håkan Alm, Institutionen för ekonomi, teknik och samhälle, Luleå Tekniska Universitet Tid: Tisdag 11 november 2014, kl. 10.00 Plats: E243, Luleå tekniska universitet</p>
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Nasiopoulos, Panagiotis. "Adaptive compression coding." Thesis, University of British Columbia, 1988. http://hdl.handle.net/2429/28508.
Testo completoAbstract (sommario):
An adaptive image compression coding technique, ACC, is presented. This algorithm is shown to preserve edges and give better quality decompressed pictures and better compression ratios than that of the Absolute Moment Block Truncation Coding. Lookup
tables are used to achieve better compression rates without affecting the visual quality of the reconstructed image. Regions with approximately uniform intensities are successfully detected by using the range and these regions are approximated by their average. This procedure leads to further reduction in the compression data rates. A method for preserving edges is introduced. It is shown that as more details are preserved around edges the pictorial results improve dramatically. The ragged appearance of the edges in AMBTC is reduced or eliminated, leading to images far superior than those of AMBTC.
For most of the images ACC yields Root Mean Square Error smaller than that obtained
by AMBTC. Decompression time is shown to be comparable to that of AMBTC for low threshold values and becomes significantly lower as the compression rate becomes
smaller. An adaptive filter is introduced which helps recover lost texture at very low compression rates (0.8 to 0.6 b/p, depending on the degree of texture in the image). This algorithm is easy to implement since no special hardware is needed.<br>Applied Science, Faculty of<br>Electrical and Computer Engineering, Department of<br>Graduate
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Fu, Ye. "Robust adaptive control." Thesis, University of British Columbia, 1989. http://hdl.handle.net/2429/30574.
Testo completoAbstract (sommario):
This thesis describes discrete robust adaptive control methods based on using slow sampling and slow adaptation. For the stability analysis, we consider that the plant model order is not exactly known and assume that the estimation model order is lower than the plant model order. A stability condition is derived with a given upper limit for the adaptation gain which is related to a strictly positive real operator. Discussion of the relation between sampling and stability condition is then given. For the robust adaptive control design, we study slow adaptation and predictive control. For the slow adaptation, the main idea is to use only good estimates and use a compensation filter. Some frequency domain information on the plant is necessary for this method. For predictive control, we discuss the relationship between the extended control horizon and the critical sampling. For a simple case, it is shown that the larger extended control horizon brings more robust adaptive control.
The purpose of this thesis is to provide robust discrete adaptive controller design guidelines, especially in such cases as using slow sampling frequency, slow adaptation rate. It is true that in practice, for various discrete adaptive control algorithms, slow sampling and slow adaptation rate will bring more robustness. The use of slow sampling and slow adaptation rate is simple and economic, thus a careful choice of sampling rate and adaptation rate is highly recommended. This thesis provides such guidelines for choosing proper sampling rate and adaptation rate for robust discrete adaptive control.<br>Applied Science, Faculty of<br>Electrical and Computer Engineering, Department of<br>Graduate
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González, Vélez Horacio. "Adaptive structured parallelism." Thesis, University of Edinburgh, 2008. http://hdl.handle.net/1842/29122.
Testo completoAbstract (sommario):
Algorithmic skeletons abstract commonly-used patterns of parallel computation, communication, and interaction. Parallel programs are expressed by interweaving parameterised skeletons analogously to the way in which structured sequential programs are developed, using well-defined constructs. Skeletons provide top-down design composition and control inheritance throughout the program structure. Based on the algorithmic skeleton concept, structured parallelism provides a high-level parallel programming technique which allows the conceptual description of parallel programs whilst fostering platform independence and algorithm abstraction. By decoupling the algorithm specification from machine-dependent structural considerations, structured parallelism allows programmers to code programs regardless of how the computation and communications will be executed in the system platform. Meanwhile, large non-dedicated multiprocessing systems have long posed a challenge to known distributed systems programming techniques as a result of the inherent heterogeneity and dynamism of their resources. Scant research has been devoted to the use of structural information provided by skeletons in adaptively improving program performance, based on resource utilisation. This thesis presents a methodology to improve skeletal parallel programming in heterogeneous distributed systems by introducing adaptivity through resource awareness. As we hypothesise that a skeletal program should be able to adapt to the dynamic resource conditions over time using its structural forecasting information, we have developed ASPara: Adaptive Structured Parallelism. ASPara is a generic methodology to incorporate structural information at compilation into a parallel program, which will help it to adapt at execution. By means of the skeleton API, ASPara instruments a skeletal program with a series of pragmatic rules, which depend on particular performance thresholds based on the nature of the skeleton, the computation/communication ratio of the program, and the availability of resources in the system. Every rule essentially determines the scheduling for the given skeleton. ASpara is comprised of four phases: programming, compilation, calibration, and execution. We illustrate the feasibility of this approach and its associated performance improvements using independent case studies based on two algorithmic skeletons, the task farm and the pipeline, programmed in C and MPI and executed in a non-dedicated heterogeneous bi-cluster system.
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Williams, Ross Neil. "Adaptive data compression." Adelaide, 1989. http://web4.library.adelaide.edu.au/theses/09PH/09phw7262.pdf.
Testo completo
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Abdel-Khalik, Hany Samy. "Adaptive Core Simulation." NCSU, 2004. http://www.lib.ncsu.edu/theses/available/etd-10252004-094938/.
Testo completoAbstract (sommario):
The work presented in this thesis is a continuation of a master?s thesis research project conducted by the author to gain insight into the applicability of inverse methods to developing adaptive simulation capabilities for core physics problems. Use of adaptive simulation is intended to improve the fidelity and robustness of important core attributes predictions such as core power distribution, thermal margins and core reactivity. Adaptive simulation utilizes a selected set of past and current reactor measurements of reactor observables to adapt the simulation in a meaningful way that is reflected in higher fidelity and robustness of the adapted core simulators models. We propose an inverse theory approach in which the multitudes of input data to core simulators, i.e. reactor physics and thermal-hydraulic data, are to be adjusted to improve agreement with measured observables while keeping core simulators models unadapted. At a first glance, devising such adaption for typical core simulators models would render the approach impractical. This follows, since core simulators are based on very demanding computational models, i.e. based on complex physics models with millions of input data and output observables. This would spawn not only several prohibitive challenges but also numerous disparaging concerns. The challenges include the computational burdens of the sensitivity-type calculations required to construct Jacobian operators for the core simulators models. Also, the computational burdens of the uncertainty-type calculations required to estimate the uncertainty information of core simulators input data presents a demanding challenge. The concerns however are mainly related to the reliability of the adjusted input data. We demonstrate that the power of our proposed approach is mainly driven by taking advantage of this unfavorable situation and show that significant reductions in both computational and storage burdens can be attained for a typical BWR core simulator adaption problem without compromising the quality of the adaption.
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Spronck, Pieter Hubert Marie. "Adaptive game AI." [Maastricht] : Maastricht : UPM, Universitaire Pers Maastricht ; University Library, Maastricht University [Host], 2005. http://arno.unimaas.nl/show.cgi?fid=5330.
Testo completo
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Marshall, Jonathan W. "Adaptive [re]use." PDF viewer required Home page for entire collecton, 2007. http://archives.udmercy.edu:8080/dspace/handle/10429/9.
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Mitchell, Bradley Yilmaz Levent. "Symbiotic adaptive multisimulation." Auburn, Ala., 2007. http://repo.lib.auburn.edu/2007%20Fall%20Theses/Mitchell_Bradley_53.pdf.
Testo completo
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Jervis, Timothy Tristram. "Connectionist adaptive control." Thesis, University of Cambridge, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.319554.
Testo completo
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Mayfield, Andrew James. "Adaptive mesh refinement." Thesis, University of Oxford, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.358687.
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練偉森 and Wai-sum Lin. "Adaptive parallel rendering." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1999. http://hub.hku.hk/bib/B31221415.
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Bontcheva, Kalina Lubomirova. "Generating adaptive hypertext." Thesis, University of Sheffield, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.369961.
Testo completo
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Abu-Bakar, Nordin. "Adaptive genetic algorithms." Thesis, University of Essex, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.343268.
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Raja, Yogesh. "Adaptive visual sampling." Thesis, Queen Mary, University of London, 2010. http://qmro.qmul.ac.uk/xmlui/handle/123456789/607.
Testo completoAbstract (sommario):
Various visual tasks may be analysed in the context of sampling from the visual field. In visual psychophysics, human visual sampling strategies have often been shown at a high-level to be driven by various information and resource related factors such as the limited capacity of the human cognitive system, the quality of information gathered, its relevance in context and the associated efficiency of recovering it. At a lower-level, we interpret many computer vision tasks to be rooted in similar notions of contextually-relevant, dynamic sampling strategies which are geared towards the filtering of pixel samples to perform reliable object association. In the context of object tracking, the reliability of such endeavours is fundamentally rooted in the continuing relevance of object models used for such filtering, a requirement complicated by realworld conditions such as dynamic lighting that inconveniently and frequently cause their rapid obsolescence. In the context of recognition, performance can be hindered by the lack of learned context-dependent strategies that satisfactorily filter out samples that are irrelevant or blunt the potency of models used for discrimination. In this thesis we interpret the problems of visual tracking and recognition in terms of dynamic spatial and featural sampling strategies and, in this vein, present three frameworks that build on previous methods to provide a more flexible and effective approach. Firstly, we propose an adaptive spatial sampling strategy framework to maintain statistical object models for real-time robust tracking under changing lighting conditions. We employ colour features in experiments to demonstrate its effectiveness. The framework consists of five parts: (a) Gaussian mixture models for semi-parametric modelling of the colour distributions of multicolour objects; (b) a constructive algorithm that uses cross-validation for automatically determining the number of components for a Gaussian mixture given a sample set of object colours; (c) a sampling strategy for performing fast tracking using colour models; (d) a Bayesian formulation enabling models of object and the environment to be employed together in filtering samples by discrimination; and (e) a selectively-adaptive mechanism to enable colour models to cope with changing conditions and permit more robust tracking. Secondly, we extend the concept to an adaptive spatial and featural sampling strategy to deal with very difficult conditions such as small target objects in cluttered environments undergoing severe lighting fluctuations and extreme occlusions. This builds on previous work on dynamic feature selection during tracking by reducing redundancy in features selected at each stage as well as more naturally balancing short-term and long-term evidence, the latter to facilitate model rigidity under sharp, temporary changes such as occlusion whilst permitting model flexibility under slower, long-term changes such as varying lighting conditions. This framework consists of two parts: (a) Attribute-based Feature Ranking (AFR) which combines two attribute measures; discriminability and independence to other features; and (b) Multiple Selectively-adaptive Feature Models (MSFM) which involves maintaining a dynamic feature reference of target object appearance. We call this framework Adaptive Multi-feature Association (AMA). Finally, we present an adaptive spatial and featural sampling strategy that extends established Local Binary Pattern (LBP) methods and overcomes many severe limitations of the traditional approach such as limited spatial support, restricted sample sets and ad hoc joint and disjoint statistical distributions that may fail to capture important structure. Our framework enables more compact, descriptive LBP type models to be constructed which may be employed in conjunction with many existing LBP techniques to improve their performance without modification. The framework consists of two parts: (a) a new LBP-type model known as Multiscale Selected Local Binary Features (MSLBF); and (b) a novel binary feature selection algorithm called Binary Histogram Intersection Minimisation (BHIM) which is shown to be more powerful than established methods used for binary feature selection such as Conditional Mutual Information Maximisation (CMIM) and AdaBoost.
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GUTIERRES, RICARDO. "ADAPTIVE HEURISTIC CONTROLLERS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 1991. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=9409@1.
Testo completoAbstract (sommario):
CENTRO DE PESQUISAS LEOPOLDO AMÉRICO MIGUEZ DE MELLO<br>Um controlador Heurístico Adaptativo baseia-se num
conjunto de regras lingüísticas para conduzir um processo
com modelo impreciso ou complexo ao estado desejado. O
comportamento do processo deve respeitar os requisitos de
performance predefinidos. Para satisfazer estes objetivos,
a estrutura interna do controle sofre mudanças para adequá-
la as condições vigentes no processo.
Os métodos de adaptação abordados consideram a modificação
de uma estrutura matricial interpretada como as correções
incrementais, compatíveis com os ajustes a serem efetuados
sobre o processo, ou como regras, constituídas por
variáveis nebulosas, que requerem manipulações adicionais
para produzir a saída do controlador. Em qualquer dos
casos, a adaptação é realizada a partir de uma Tabela de
Índices de Performance. Para facilitar a sua obtenção é
implementado um procedimento, que fornece a representação
matricial das regras lingüísticas, concatenadas na forma
de um Algoritmo Lingüístico de Controle.
O comportamento dinâmico do Sistema, composto pelos
Controladores Heurísticos e por processos com modelos
distintos, é considerado para Tabelas de índices de
Performance com várias dimensões. As regras lingüísticas,
correlacionadas com estas tabelas, foram elaboradas com
diversas classes de atributos.
As simulações realizadas concentram-se sobre os parâmetros
dos controladores, que influenciam significativa-
Os estudos abordam também o comportamento da estrutura
interna destes controladores e o seu desempenho em termos
da velocidade de atuação sobre o processo.<br>A heuristic Controller uses a set of linguistic rules,
which are derived from expertise or human operators´
skills, in order to achieve control of processes that have
inaccurate or complex models.
An adaptative Heuristic Controller adjusts the set of
rules in an automatic and continuous way, aiming to
achieve prescribed objectives indicated by a performance
measure.
The adaptative procedures modify a matrix, the elements of
which are either incremental corrections or numeric rules
associated with fuzzy variables. In both cases a
Performance Index Table and a learning method are employed
to correct that matrix. The Performance Table is a matrix
calculated from a set of linguistic rules.
The controllers are implemented with different Performance
Tables, considering various sets of linguistic values and
quantization levels.
The dynamic behaviour of overdamped and underdamped
processes is investigated. The performance of simulated
systems is analyzed with respect to relevant parameters
that affect their behaviour.
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Lee, Bernard K. 1975. "Adaptive structural control." Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/50021.
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Benardete, Emma A. 1973. "Rethinking adaptive reuse." Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/64558.
Testo completoAbstract (sommario):
Thesis (M.Arch.)--Massachusetts Institute of Technology, Dept. of Architecture, 2002.<br>Includes bibliographical references (p. [109]-[111]).<br>Adaptive reuse of manufacturing plants in post-industrial countries has become an increasing trend. In the United States, evidence of our industrial past is present in both urban and rural landscapes. The appearance of "brownfields" is due to the change in the U.S. economy from heavy industry and the manufacturing of commodities to the digitized products and supports required of the information age. The need to recycle these lands is part of the realities we face, as we become increasingly aware of the environmental damage caused by the industrial age. Paterson, NJ is the oldest industrial site in America founded by Alexander Hamilton. He chose it because the seventy-foot Great Falls was a prime source of hydroelectric power. He laid foundations in the city that helped make Paterson a prime textile-manufacturing center throughout the nineteenth and early part of the twentieth centuries. Since the 1960s, Paterson has experienced a decline in its industrial economic base. The city has sought to regenerate interest in the area through historic trails and the attraction of the Great Falls. These efforts have failed. However, through out its history Paterson has been the site of adaptive reuse. The mills and factories constantly had to change in order to keep pace with new technology. Currently, several mills have been renovated to form apartments for artists. While providing picturesque housing, these renovated mills no longer have a place in the piecemeal industries that still exist. This type of renewal has not helped to reunify this community. To counteract these singular interventions I have proposed reprogramming the central industrial area around the Falls as a center for Ecologists and Environmental Artists. The urban strategy I have adopted is one of creating desire for the current transient population to remain in the area and reinvest in the existing infrastructure. I have used nature to unify the area by artificially reinserting nature where, before Hamilton, nature flourished. A path unifies the area taking the pedestrian through the natural and artificial (man-made) topography of this landscape. The landscape offers sectional characteristics, which I have tried to make the pedestrian aware: aerial, canopic, terrestrial, aquatic, and sub-terrestrial. The path illustrates that we are always moving between sky and water. While the mountain and river offer some geographical orientation, once the pedestrian is embedded in the existing urban fabric, his sense of direction may become obfuscated. The path begins by orientating the pedestrian North and over the course of his walk, if repeated over the course of a year, he would find that the summer and winter solstices help strengthen his sectional placement within this landscape. Along the path I have interjected sustainable infrastructures in order to show how the industrial past can help us revitalize our landscape for a post-industrial future. In my own renovation of certain buildings, I have tried to create a balance between nostalgia for the past and romance for new technology. F or nostalgia does not necessitate a recreation of what once was, but can reintroduce us to the past's own love and desire for the future.<br>by Emma A. Benardete.<br>M.Arch.
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Ward, David James. "Adaptive computer interfaces." Thesis, University of Cambridge, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.620273.
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Adamskiy, Dmitry. "Adaptive online learning." Thesis, Royal Holloway, University of London, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.591060.
Testo completoAbstract (sommario):
The research that constitutes this thesis was driven by the two related goals in mind. The first one was to develop new efficient online learning algorithms and to study their properties and theoretical guarantees. The second one was to study real-world data and find algorithms appropriate for the particular real-world problems. This thesis studies online prediction with few assumptions about the nature of the data. This is important for real-world applications of machine learning as complex assumptions about the data are rarely justified. We consider two frameworks: conformal prediction, which is based on the randomness assumption, and prediction with expert advice, where no assumptions about the data are made at all. Conformal predictors are set predictors, that is a set of possible labels is issued by Learner at each trial. After the prediction is made the real label is revealed and Learner's prediction is evaluated. 10 case of classification the label space is finite so Learner makes an error if the true label is not in the set produced by Learner. Conformal prediction was originally developed for the supervised learning task and was proved to be valid in the sense of making errors with a prespecified probability. We will study possible ways of extending this approach to the semi-supervised case and build a valid algorithm for this t ask. Also, we will apply conformal prediction technique to the problem of diagnosing tuberculosis in cattle. Whereas conformal prediction relies on just the randomness assumption, prediction with expert advice drops this one as well. One may wonder whether it is possible to make good predictions under these circumstances. However Learner is provided with predictions of a certain class of experts (or prediction strategies) and may base his prediction on them. The goal then is to perform not much worse than the best strategy in the class. This is achieved by carefully mixing (aggregating) predictions of the base experts. However, often the nature of data changes over time, such that there is a region where one expert is good, followed by a region where another is good and so on. This leads to the algorithms which we call adaptive: they take into account this structure of the data. We explore the possibilities offered by the framework of specialist experts to build adaptive algorithms. This line of thought allows us then to provide an intuitive explanation for the mysterious Mixing Past Posteriors algorithm and build a new algorithm with sharp bounds for Online Multitask Learning.
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Love, Lonnie J. "Adaptive impedance control." Diss., Georgia Institute of Technology, 1995. http://hdl.handle.net/1853/15911.
Testo completo
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Vera, Azócar Alberto Abel. "Adaptive rumor spreading." Tesis, Universidad de Chile, 2015. http://repositorio.uchile.cl/handle/2250/134778.
Testo completoAbstract (sommario):
Magíster en Gestión de Operaciones<br>Ingeniero Civil Industrial<br>El esparcimiento de rumores es un modelo intuitivo para la difusión de información en una red social.
Una entidad que controla la red, por ejemplo el proveedor del servicio, desea acelerar el proceso de esparcimiento del rumor, de forma tal que se maximice la cantidad de información entregada.
Este problema, definido a grandes rasgos, ha sido objeto de múltiples investigaciones en el último tiempo, entre otros como marketing viral y maximización de influencia.
Un enfoque natural y ausente en los estudios previos es la adaptividad. En este trabajo se abordan las siguientes preguntas: ¿cómo el controlador puede usar la información del estado de la red para acelerar el proceso de rumor? y ¿cuánto beneficio se obtiene de tal conocimiento?
Un concepto novedoso es la comunicación oportunista en redes; cada agente de la red social comparte información (noticias, actualización de software, etc.) con otros usuarios al momento de estar momentáneamente en rango (vía wi-fi, bluetooth, etc.), de esta forma se evita la saturación de la infraestructura que soporta la red.
Con esta motivación se estudia un modelo a tiempo continuo, donde cada par de nodos se comunica de acuerdo a un proceso de Poisson de cierta tasa y el rumor se transmite siempre que alguno estuviera informado.
Las anteriores comunicaciones no tienen costo para el controlador, pero si éste lo desea puede informar a cualquier nodo pagando un costo unitario por ello.
En vez de la usual restricción de presupuesto se fija un deadline, en tal tiempo todos los nodos deben estar informados, debiendo pagar el controlador un costo unitario por cada nodo que no haya obtenido el rumor antes del deadline.
Una estrategia no-adaptativa puede informar sólo al comienzo del periodo y cuando se cumple el deadline, pagando por todos aquellos nodos que no se comunicaron nunca con otro nodo informado. Una estrategia adaptativa puede intervenir la red en cualquier instante, usando toda la información disponible hasta ese entonces, en particular sabiendo cuales nodos tienen el rumor en cada momento.
El resultado principal de este trabajo es que en el caso homogéneo, donde cada par de nodos se encuentra con la misma tasa, el beneficio de la adaptividad está acotado por una constante.
La demostración requiere un entendimiento profundo del proceso estocástico que domina el sistema, que se cree ya una contribución interesante.
Adicionalmente, se presenta una extensión natural del caso homogéneo, donde el controlador está interesado sólo en un conjunto de nodos y no en toda la red social, se demuestra que en este escenario el beneficio de la adaptividad también está acotado por una constante.
Finalmente, se muestra que, sin el supuesto de homogeneidad, el beneficio de la adaptividad puede crecer de forma no acotada.
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Choudhury, Sanjiban. "Adaptive Motion Planning." Research Showcase @ CMU, 2018. http://repository.cmu.edu/dissertations/1212.
Testo completoAbstract (sommario):
Mobile robots are increasingly being deployed in the real world in response to a heightened demand for applications such as transportation, delivery and inspection. The motion planning systems for these robots are expected to have consistent performance across the wide range of scenarios that they encounter. While state-of-the-art planners, with provable worst-case guarantees, can be employed to solve these planning problems, their finite time performance varies across scenarios. This thesis proposes that the planning module for a robot must adapt its search strategy to the distribution of planning problems encountered to achieve real-time performance. We address three principal challenges of this problem. Firstly, we show that even when the planning problem distribution is fixed, designing a nonadaptive planner can be challenging as the performance of planning strategies fluctuates with small changes in the environment. We characterize the existence of complementary strategies and propose to hedge our bets by executing a diverse ensemble of planners. Secondly, when the distribution is varying, we require a meta-planner that can automatically select such an ensemble from a library of black-box planners. We show that greedily training a list of predictors to focus on failure cases leads to an effective meta-planner. For situations where we have no training data, we show that we can learn an ensemble on-the-fly by adopting algorithms from online paging theory. Thirdly, in the interest of efficiency, we require a white-box planner that directly adapts its search strategy during a planning cycle. We propose an efficient procedure for training adaptive search heuristics in a data-driven imitation learning framework. We also draw a novel connection to Bayesian active learning, and propose algorithms to adaptively evaluate edges of a graph. Our approach leads to the synthesis of a robust real-time planning module that allows a UAV to navigate seamlessly across environments and speed-regimes. We evaluate our framework on a spectrum of planning problems and show closed-loop results on 3 UAV platforms - a full-scale autonomous helicopter, a large scale hexarotor and a small quadrotor. While the thesis was motivated by mobile robots, we have shown that the individual algorithms are broadly applicable to other problem domains such as informative path planning and manipulation planning.We also establish novel connections between the disparate fields of motion planning and active learning, imitation learning and online paging which opens doors to several new research problems.
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Pollard, John. "Adaptive distance sampling." Thesis, University of St Andrews, 2002. http://hdl.handle.net/10023/15176.
Testo completoAbstract (sommario):
We investigate mechanisms to improve efficiency for line and point transect surveys of clustered populations by combining the distance methods with adaptive sampling. In adaptive sampling, survey effort is increased when areas of high animal density are located, thereby increasing the number of observations. We begin by building on existing adaptive sampling techniques, to create both point and line transect adaptive estimators, these are then extended to allow the inclusion of covariates in the detection function estimator. However, the methods are limited, as the total effort required cannot be forecast at the start of a survey, and so a new fixed total effort adaptive approach is developed. A key difference in the new method is that it does not require the calculation of the inclusion probabilities typically used by existing adaptive estimators. The fixed effort method is primarily aimed at line transect sampling, but point transect derivations are also provided. We evaluate the new methodology by computer simulation, and report on surveys of harbour porpoise in the Gulf of Maine, in which the approach was compared with conventional line transect sampling. Line transect simulation results for a clustered population showed up to a 6% improvement in the adaptive density variance estimate over the conventional, whilst when there was no clustering the adaptive estimate was 1% less efficient than the conventional. For the harbour porpoise survey, the adaptive density estimate cvs showed improvements of 8% for individual porpoise density and 14% for school density over the conventional estimates. The primary benefit of the fixed effort method is the potential to improve survey coverage, allowing a survey to complete within a fixed time and effort; an important feature if expensive survey resources are involved, such as an aircraft, crew and observers.
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Jenson, Audra Christine. "Adaptive Preference Tradeoffs." Thesis, Virginia Tech, 2018. http://hdl.handle.net/10919/83433.
Testo completoAbstract (sommario):
Consider the following scenario: A mother chooses to marry off her 10 year-old daughter, not because she doesn’t know the harmful effects of child marriage, nor because she thinks that it is good that her daughter marries when she is 10 years old. Rather, she is unable to feed her daughter and realizes that her daughter’s survival depends upon her marrying a financially stable man. This is an apparent example of what human development practitioners and political philosophers call an adaptive preference (AP): a preference, formed under oppressive circumstances, that seems to perpetuate the agent’s own oppression. Prevailing opinion is that forced tradeoffs—especially following Serene Khader’s taxonomy—, like the case presented above, are a type of AP: one in which a person makes a decision because of a limited option set. In this paper I argue that no paradigm cases of forced tradeoffs should not be classified as APs. Instead, I offer a revised definition of adaptive preferences where I argue that adaptive preferences are psychological traits that cause the agent with adaptive preferences to make irrational or uninformed decisions that perpetuate their own oppression. I defend this new definition by exploring the implications of changing the definition. In particular, forced tradeoffs involve different kinds of interventions from other kinds of adaptive preferences and including forced tradeoffs risks committing testimonial injustice against those who have limited option sets.<br>Master of Arts
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Ryan, James Gregory Carleton University Dissertation Engineering Electrical. "Subband adaptive filters." Ottawa, 1992.
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Moyka, Ana S. "Adaptive vibration absorber." Diss., This resource online, 1996. http://scholar.lib.vt.edu/theses/available/etd-10052007-143216/.
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Berry, Dominic William. "Adaptive phase measurements /." [St. Lucia, Qld.], 2002. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe16247.pdf.
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Lin, Wai-sum. "Adaptive parallel rendering /." Hong Kong : University of Hong Kong, 1999. http://sunzi.lib.hku.hk/hkuto/record.jsp?B20868236.
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Banda, Nagamani. "Adaptive video segmentation." Morgantown, W. Va. : [West Virginia University Libraries], 2004. https://etd.wvu.edu/etd/controller.jsp?moduleName=documentdata&jsp%5FetdId=3520.
Testo completoAbstract (sommario):
Thesis (M.S.)--West Virginia University, 2004.<br>Title from document title page. Document formatted into pages; contains vi, 52 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 50-52).
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Williams, Hywel Thomas Parker. "Homeostatic adaptive networks." Thesis, University of Leeds, 2006. http://etheses.whiterose.ac.uk/1344/.
Testo completoAbstract (sommario):
Homeostasis is constancy in the face of perturbation. The concept was originally developed to describe the fixed internal environment of an organism and this descriptive view of homeostasis has been prevalent in literature. However, homeostasis cal also be seen as the dynamic process of self-regulation and as such it is an organising principle by which systems adapt their behaviour over time. In this thesis we adopt this casual view of homeostasis and develop a theory of homeostatic adaptive systems. We study homeostatic adaptive networks by looking at specific examples of homeo-static systems: the Homeostat, homeostatic plasticity in neural networks, and homeostatic regulation of the environment by the biota. Investigation of these cases studies forms the basis for the development of a generalised theory of homeostatic adaptive systems. The Homeostat was an electromechanical device designed by W.A. Ross Ashby to demonstrate the principle of ultra stability, where the stability of a system requires homeostasis of essential variables. Ashby put forward a theory of mammalian learning as a process of homeostatic adaptation that was based on the idea of the ultra stable system. Here we develop a simulated Homeostat and explore its properties as a homeostatic adaptive system, looking at its ultra stable nature and its ability to adapt to external perturbations. The second case study, neural homeostasis, has recently been a topic much interest in the neurosciences, with new data being presented concerning the existence and functioning of a variety of mechanisms by which neural activity is regulated. Homeostatic plastic mechanisms prevent long term quiescence or hyper-excitation in biological neurons and this suggests that such mechanisms may be used to solve the problem of node saturation in artificial neuron networks. Here we develop homeostatic plastic mechanisms for use in continuous-time recurrent neural networks; a kind of network often used in evolutionary robotics, and studies the effect of these mechanisms on network behaviour. Node saturation effects can make these networks difficult to evolve as robot controllers and we also look at the effect of homeostatic plasticity on evolvabilty. The third case study is the evolution of homeostatic regulation of the physical environment by the biota. The Gaia theory state that life regulates the entire biosphere to conditions suitable for life, but the general concept of biological regulation of the environment is applicable on a variety of scales. However, there are major theoretical issues concerning the compatibility of environmental regulation with environmental theory. Here we develop a modified version of the Daisyworld model and use it to determine the compatibility of global regulation with individual selection. We show that regulation in Daisyworld depends on several key assumptions and fails if these assumptions are removed. We develop the Flask model, in which environmental regulation by microbial communities evolves as a result of multi-level selection, in order to show how regulation can occur when the core assumptions of Daisyword are relaxed. At the end of the thesis we try to draw some general conclusions concerning homeostatic adaptive systems. We consider the adaptive and homeostatic properties of each of the case study systems, and then generalise from these to give some principles of homeostatic adaptation. Our analysis shows that the perturbations to a system can be classified in terms of their effects on homeostasis, and that the ability of a system to adapt to a perturbation and maintain homeostasis depends on the variety of responses it can produce. We argue that the parameter change caused by a loss of homeostasis depends on the variety of responses it can produce. We argue that parameter change caused by a loss of homeostasis causes 'organisation death' in a homeostatic adaptive system, where the system does not survive in its current form. This suggests a view of learning and evolution of organisms as second order homeostatic adaptive process.