Dissertations / Theses on the topic 'Adaptable systems'

Audience Response Systems (ARSs) provide a promising opportunity to address issues occurring in traditional higher education, e.g., the lack of interaction, by allowing students to participate anonymously in lectures using their mobile devices. This can promote the students' attention, increase the interaction between the lecturer and the students and foster active thinking during class. In order to choose an appropriate ARS, numerous surveys list and classify these systems according to different criteria, e.g., supported features and platforms. [From the introduction]

Telecommunication service systems have been developing rapidly during the last five decades. The service architectures as well as the technologies for design, implementation, deployment, execution, and management of the services have been under continuous development. The focus of this thesis is mobility management in adaptable service systems. Adaptable service systems are service systems that adapt dynamically to changes in both time and position related to users, nodes, capabilities, status and changed service requirements and mobility management is the handling of movements of the various components that can potentially move. As examples persons, services, terminals, nodes, capabilities, data and programs can move. Mobility management allows services to find locations, and to deliver certain content to the users or terminals regardless of their location. This thesis is focusing on the movement of persons, services, programs and terminals.

The thesis is related to TAPAS (Telematics Architecture for Playbased Adaptable Service Systems) research project. This project started in 1997 and has been founded by the Norwegian Research Council and the Department of Telematics at NTNU.

The thesis has four main parts: 1) a generic terminology framework, 2) a mobility management architecture, 3) a design model for the basic mechanism used to specify and realize the services, i.e. the role-figure model, and 4) a formal model and analysis of the role-figure model. The terminology framework is the basis for the mobility management architecture. Three main mobility types are handled. These types are personal mobility, role-figure mobility, and terminal mobility. For each of these mobility types a set of generic concepts, definitions, and requirement rules are presented.

The mobility management architecture defines the structure and the functionality of the entities needed to handle the various mobility types. The mobility management architecture is worked out within the context of TAPAS.

The role-figure model is an abstract model for the implemented rolefigure functionality. It has parts such as behaviour, capabilities, interfaces, messages, and executing methods. By using an ODP (Open Distributed Processing) semantic framework and the rewriting logic, the structure of the cooperating role-figures and their behaviour is defined.

This model will be used as the basis for a formal model specified in Maude, which is a language and tool supporting specification and analysis of rewriting logic theories. It is used to reason about the structure and the behaviour of the role-figures and the proposed solution for role-figure mobility.

This thesis proposed solutions to some shortcomings to current eLearning architectures. The proposed DeLC architecture supports context-aware and adaptable provision of eLearning services and electronic content. The architecture is fully distributed and integrates service-oriented development with agent technology. Central to this architecture is that a node is our unit of computation (known as eLearning node) which can have purely service-oriented architecture, agent-oriented architecture or mixed architecture. Three eLeaerning Nodes have been implemented in order to demonstrate the vitality of the DeLC concept. The Mobile eLearning Node uses a three-level communication network, called InfoStations network, supporting mobile service provision. The services, displayed on this node, are to be aware of its context, gather required learning material and adapted to the learner request. This is supported trough a multi-layered hybrid (service- and agent-oriented) architecture whose kernel is implemented as middleware. For testing of the middleware a simulation environment has been developed. In addition, the DeLC development approach is proposed. The second eLearning node has been implemented as Education Portal. The architecture of this node is poorly service-oriented and it adopts a client-server architecture. In the education portal, there are incorporated education services and system services, called engines. The electronic content is kept in Digital Libraries. Furthermore, in order to facilitate content creators in DeLC, the environment Selbo2 was developed. The environment allows for creating new content, editing available content, as well as generating educational units out of preexisting standardized elements. In the last two years, the portal is used in actual education at the Faculty of Mathematics and Informatics, University of Plovdiv. The third eLearning node, known as Agent Village, exhibits a purely agent-oriented architecture. The purpose of this node is to provide intelligent assistance to the services deployed on the Education Pportal. Currently, two kinds of assistants are implemented in the node - eTesting Assistants and Refactoring eLearning Environment (ReLE). A more complex architecture, known as Education Cluster, is presented in this thesis as well. The Education Cluster incorporates two eLearning nodes, namely the Education Portal and the Agent Village. eLearning services and intelligent agents interact in the cluster.

Currently, European small and medium-sized enterprises (SMEs) are experiencing increasing pressure to provide high quality goods with customised features while at the same time remain cost effective and competitive in the global market. In the future, manufacturing systems need to be able to cope with constantly changing market requirements. Consequently, there is a need to develop the research foundations for a new generation of manufacturing systems composed of intelligent autonomous entities which are able to reconfigure themselves and to adapt their performance as a result of product and environmental changes. The research described in this thesis addresses the issue by developing three distinctive elements of an adaptation framework for next-generation manufacturing systems. The first element is a capability-based data model for the representation of manufacturing resources to enable self-awareness. The model captures the resources’ life cycle and performance indicators to provide information about the resources’ condition. The second element is a multi-agent architecture for plug and produce and the reconfiguration of manufacturing systems. The resource data model is utilised by the agent society, which is able to instantiate a model to represent a physical resource in the virtual agent society. The shift to the virtual environment enables a communication infrastructure for heterogeneous resources and the application of the digital twin concept. The agent architecture applies negotiation techniques to establish a plan for system adaptation. The third element is a methodology for automated experience-based manufacturing system adaptation. The adaptation methodology is based on previous runtime experience instances to generate adaptation knowledge. The information generated is applied to the current context and part of the agent negotiation which is dynamically executed in case of a disturbance. Collectively, these three elements significantly increase the flexibility and reconfigurability of a manufacturing system reducing the time required for integration and maintenance of complex systems on demand, improving their effectiveness. The developed framework is implemented and evaluated experimentally on a physical, industrial standard demonstrator and using a virtual simulation model. The experimental results confirm a significant step towards new solutions for the deployment of self-adaptable intelligent manufacturing systems.

Networked services have been an important research topic for over 40 years. These days, the amount and variety of services are growing enormously at the same time as the complexity and heterogeneity of the service systems is also increasing. Adaptable services and service systems are a research issue aiming to cope with the complexity.

Adaptable Service Systems are service systems that are able to adapt dynamically to changes in time and position related to users, nodes, capabilities, status, changed service requirements and policies.

A service can be considered at different abstraction levels. In this thesis, three abstraction levels are used, denoted as the conceptual, engineered and physical services. Service engineering is the creation of conceptual, engineered and physical services. Service management is the functionality to control the provision of service functionality and quality of a service, both within and across service systems, through the service life cycle phases.

This thesis addresses some service issues related to service engineering and service management in adaptable service systems. The work presented in this thesis is related with TAPAS (Telematics Architecture for Play-based Adaptable Service Systems). On one hand, TAPAS concepts, architectures and platform are the context and the basis of the thesis. On the other hand, my research work also aims to further develop TAPAS concepts, architectures and platform. The research aims to answer the following five problem statements:

P1: How can services be modelled and represented?

P2: How can services be discovered efficiently, automatically and accurately?

P3: How can services be instantiated dynamically and according to available capabilities and status information?

P4: How can new service specifications or modifications to existing services dynamically be introduced without interrupting the executing services?

P5: How to evaluate and validate the proposed frameworks and mechanisms?

The problem statements P1-P4 are related to the following four research topics:

T1: Service representation

T2: Service discovery

T3: Service instantiation

T4: Service adaptation.

Service representation is the representation of a service (conceptual, engineered and physical) based on a specific language and a data model. Service discovery is the process of finding services that satisfy functional and non-functional requirements. It is a core functionality to locate desired services in a distributed environment. Service instantiation is the process of creating a service instance upon request and making it available to the user, and finally service adaptation is the process of adapting the structure or behaviour of the service to the various changes during its execution.

There is one-to-one mapping from P1-P4 to T1-T4. P5 is related with all the four research topics T1-T4. The problem statements P1 and P2 are further refined into subproblems.

The problem statement P1 is refined into sub-problem statements P1 1-P1.3 defined as follows:

P1.1: How to represent conceptual services?

P1.2: How to represent physical services in a flexible manner so that it is possible to adapt the services to changes dynamically?

P1.3: How to extract the component interface behaviour from the physical service representation so that compositional service verification can be applied?

The problem statement P2 is refined into sub-problem statements P2 1-P2.2 defined as follows:

P2.1: How to ensure automatic and accurate service discovery?

P2.2: How to locate services efficiently in a large-scale service system? The result of the research work is classified as nine research contributions C1-C9.

These contributions are related to the research topics and accordingly problem statements as defined below:

Research topic T1 Service representation:

• C1: Conceptual service representation. This contribution addresses P1.1. An integrated semantic service description based on a service ontology is proposed and is represented using Web Services and Semantic Web languages. The service ontology defines a model of functional and non-functional properties, where the service functionality is represented as operations, inputs, outputs, preconditions and effects and the non-functional properties include service parameters, Quality of Service (QoS) parameters and policies consisting of business policies, QoS policies and context policies. Such semantic-annotated service description is the basis for semantic matching procedure in service discovery.

• C2: Physical service representation. This contribution addresses P1 2. XML (eXtensible Markup Language) is the physical service representation language. An Extended Finite State Machine (EFSM)-based XML manuscript data model is defined. It is based on modifiable and parameterized behaviour patterns, separating action types from actual action codes. Service functionality is further classified into Action Groups and Capability Categories according to the nature of actions and the dependability on capability respectively. Such manuscript data model is the basis for service instantiation and adaptation.

• C3: Preparation for service verification. This contribution addresses P1.3. Service verification is the process of checking service specifications to ensure that service components can play well together. In order to utilize compositional verification based on an interface type language, rules are given for automatic translation from EFSM-based XML manuscript to the interface type language. Projection technique is applied during the translation process.

Research topic T2 Service discovery:

• C4: Semantic service discovery procedure. This contribution addresses P2.1. An integrated semantic service description model is defined based on a service ontology (i.e. the conceptual service representation). An integrated semantic discovery procedure based on such service descriptions is proposed for semantic matching of both functional and non-functional properties. Such procedure consists of both ontological inference and rule-based reasoning andhas been implemented on a Reasoning Machine (RM).

• C5: Super-peer Semantic Overlay Network (SON)-based service discovery system. This contribution addresses P2.2. A service discovery system based on super-peer managed SONs is proposed and functionality for efficient service discovery and efficient SON management is defined. The integrated semantic service discovery procedure proposed for C4 is applied for semantic matching on selected directories (i.e. selected SONs). A self-organizing process based on an autonomous super-peer selection algorithm is applied for super-peer SONs construction and maintenance. The system performance is evaluated by simulations and the results indicate efficient service discovery (in terms of recall, messages-per-request and hops-per-request) and efficient SON management (in terms of self-organization time, management procedure overhead and load factor).

Research topic T3 Service instantiation:

• C6: Manuscript execution support – State Machine Interpreter (SMI). This contribution addresses P3. This thesis implements an execution support for service instantiation, namely the SMI, which can interpret and execute EFSMbased XML manuscripts. SMI can instantiate the manuscripts according to available capability and status information.

Research topic T4 Service adaptation:

• C7: Physical service adaptation. This contribution addresses P4. An approach for physical service adaptation is proposed based on the XML manuscripts. Given a service adaptation request, the system dynamically selects and instantiates XML manuscripts according to runtime capability and status information. The actual execution codes for the behaviour patterns defined in the manuscripts can be dynamically selected according to available capability and status. The dynamic generation of such adaptation requests according to traffic situation and failure states is not considered.

• C8: Dynamic service management framework. This contribution addresses P4 and is related with C2, C6 and C7. A RM-based framework integrating service behaviour specification (i.e. EFSM-based XML manuscript), selection (instantiation) and adaptation is proposed and prototyped. Selection and Mapping Rules are proposed and modelled.

For research topics T1-T4:

• C9: Prototypes and simulations. This contribution addresses P5 and is used to evaluate and validate the proposed frameworks and mechanisms.

In recent years, multi-tier architectures have become the standard computing environment for web- and enterprise applications. The application server tier is often the heart of the system embedding the business logic. Adaptability, in particular the capability to adjust to the load submitted to the system and to handle the failure of individual components, are of outmost importance in order to provide 7/24 access and high performance. Replication is a common means to achieve these reliability and scalability requirements. With replication, the application server tier consists of several server replicas. Thus, if one replica fails, others can take over. Furthermore, the load can be distributed across the available replicas. Although many replication solutions have been proposed so far, most of them have been either developed for fault-tolerance or for scalability. Furthermore, only few have considered that the application server tier is only one tier in a multi-tier architecture, that this tier maintains state, and that execution in this environment can follow complex patterns. Thus, existing solutions often do not provide correctness beyond some basic application scenarios.
In this thesis we tackle the issue of replication of the application server tier from ground off and develop a unified solution that provides both fault-tolerance and scalability. We first describe a set of execution patterns that describe how requests are typically executed in multi-tier architectures. They consider the flow of execution across client tier, application server tier, and database tier. In particular, the execution patterns describe how requests are associated with transactions, the fundamental execution units at application server and database tiers. Having these execution patterns in mind, we provide a formal definition of what it means to provide a correct execution across all tiers, even in case failures occur and the application server tier is replicated. Informally, a replicated system is correct if it behaves exactly as a non-replicated that never fails. From there, we propose a set of replication algorithms for fault-tolerance that provide correctness for the execution patterns that we have identified The main principle is to let a primary AS replica to execute all client requests, and to propagate any state changes performed by a transaction to backup replicas at transaction commit time. The challenges occur as requests can be associated in different ways with transactions. Then, we extend our fault-tolerance solution and develop a unified solution that provides both fault-tolerance and load-balancing. In this extended solution, each application server replica is able to execute client requests as a primary and at the same time serves as backup for other replicas. The framework provides a transparent, truly distributed and lightweight load distribution mechanism which takes advantage of the fault-tolerance infrastructure. Our replication tool is implemented as a plug-in of JBoss application server and the performance is carefully evaluated, comparing with JBoss' own replication solutions. The evaluation shows that our protocols have very good performance and compare favorably with existing solutions.

The project has been directed towards improving the accuracy and safety of marine navigation and ship handling, whilst contributing to reduced manning and improved fuel costs. Thus, the aim of the work was to investigate, design and develop an adaptable mathematical model that could be used in an integrated navigation system (INS) and an automatic collision avoidance system (ACAS) for use in marine vehicles. A general overview of automatic navigation is undertaken and consideration is given to the use of microprocessors on the bridge. Many of these systems now require the use of mathematical models to predict the vessels' manoeuvring characteristics: The different types and forms of models have been investigated and the derivation of their hydrodynamic coefficients is discussed in detail. The model required for an ACAS should be both accurate and adaptable, hence, extensive simulations were undertaken to evaluate the suitability of each model type. The modular model was found to have the most adaptable structure. All the modular components of this model were considered in detail to improve its adaptability, the number of non-linear terms in the hull module being reduced. A novel application, using the circulation theory to model the propeller forces and moments, allows the model to be more flexible compared to using traditional B-series four-quadrant propeller design charts. A new formula has been derived for predicting the sway and yaw components due to the propeller paddle wheel effect which gives a good degree of accuracy when comparing simulated and actual ship data, resulting in a mean positional error of less than 7%. As a consequence of this work, it is now possible for an ACAS to incorporate a ship mathematical model which produces realistic manoeuvring characteristics. Thus, the study will help to contribute to safety at sea.

CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO
No cenário atual do setor de telecomunicações, percebe-se uma tendência crescente em direção ao uso de sistemas de comunicação que permitam a criação rápida e de baixo custo de serviços. Na busca por arquiteturas de rede que respondam a essa tendência, vários grupos têm centrado seus esforços em pesquisas na área de redes programáveis. O surgimento da tecnologia de processamento de rede no mercado de equipamentos de telecomunicações abriu ainda maior espaço para pesquisas nessa área. Nesse contexto, é imprescindível que os processos de criação de serviços sejam bem estruturados e, o quanto possível, sistemáticos. Esta tese, inserida em um projeto desenvolvido no Laboratório TeleMídia da PUC-Rio, adota uma abordagem de criação de serviços em que técnicas de Arquitetura de Software e de Desenvolvimento Baseado em Componentes são aplicadas consistentemente e de modo ubíquo, desde especificações de alto nível de serviços até a implementação de software básico em unidades programáveis de processamento de rede. Os objetivos principais são expressar a adaptabilidade de múltiplos aspectos nesses serviços e, simultaneamente, reduzir a sobrecarga cognitiva em projetistas e programadores, decorrente dessa multiplicidade de aspectos. Para isso, foi desenvolvida uma linguagem de especificação baseada em XML, chamada Lindax, que permite descrever arquiteturalmente diversos aspectos de sistemas de comunicação - por meio de um arcabouço sintático único para DSLs - e restrições de adaptação em cada aspecto particular - por meio de estruturas de estilos arquiteturais. Complementando o trabalho, um conjunto de ferramentas de manipulação de descrições arquiteturais em LindaX é definido. Essas ferramentas permitem o refinamento para diferentes linguagens formais ou a síntese de configurações e mecanismos de controle de adaptações para diversas plataformas.
It is increasingly noticeable, in the current telecommunications market, a trend towards using communication systems that allow rapid and cheap deployment of new services. In pursuit of network architectures that keep up with such trend, significant research has been carried out on programmable networks. This field is set to gain further impetus from developments in network processor-based equipment. In this context, it is crucial that service creation processes be well structured and, as far as possible, systematic. This thesis, which is part of an ongoing project at the TeleMídia Laboratory, PUC-Rio, adopts a service creation approach in which techniques from Software Architecture and Component-Based Software Development are uniformly and ubiquitously applied at all levels of a communication system, ranging from high- level service specifications to low-level software implementation running in network processors. The main aim is to express adaptibility in cross-cutting service aspects and, meanwhile, cut down on the cognitive overhead usually imposed upon designers and programmers due to such multiplicity of concerns. For the sake of the aforementioned aim, an XML-based specification language, called LindaX, has been developed. Such language allows various system aspects to be architecturally described - by means of a single syntactic framework for DSLs - as well as adaptable in a constrained way - through style structures. Complementing the work, a toolset for handling LindaX architecture descriptions has been defined, which allows their refinement to different formal languages or their synthesis onto system configurations and adaptation controlling mechanisms for diverse platforms.

Networked Service Systems are considered. Services are realized by service components, which by their inter-working, provide a service in the role of a service provider to service users. During more than two decades, networked service systems have been an important research topic. Focus was on efficiency in the definition, deployment and execution of services. This focus now has been changed into adaptability.

Adaptable service systems are service systems that are able to adapt dynamically to changes in time and position related to users, nodes, capabilities, system performance, changed service requirements and policies.

This thesis has focus on adaptability aspects related to capabilities. A capability is defined here as an inherent property of a node, which is used as a basis for implementing a service.

Goal adaptability properties of an adaptable service system can be classified as general and core properties. The general properties are requirement to the architectural framework while the core properties are requirement to the functionality. The core properties are classified as i) re-arrangement flexibility, ii) failure robustness and iii) resource load awareness and control properties.

The realization of the goal adaptability properties both needs an appropriate architectural framework as well as management functionality. This thesis presents a solution framework for reasoning-based capability configuration management for adaptable service systems. This framework is defined to consist of five contributions. Each contribution consists of sub-contributions; each of which represents contributed concept, model or mechanism. The contributions are:

• C1: Capability-based computing architecture

• C2: Policy-based reasoning

• C3: Capability configuration management

• C4: Concept model and data representation

• C5: Scenarios - experimentation and simulation

Capability-based computing architecture is a capability and QoS-based architectural framework intended to be used for the specification and execution of any service functionality. Policy-based reasoning is a support functionality that makes adaptable service systems being able to take decisions based on flexible and expressive behavioral specification. Capability configuration management is a functionality related to capability specifications, configuration, allocation, re-allocation and optimization. Concept model and data representation is the data model applied for the formalization and representation of the concepts applied for the capability configuration management based on policy-based reasoning. Scenarios – experimentation and simulation shows the experiments and simulations that have been conducted for validating the other contributions.

My PhD work and thesis is related to TAPAS (Telematics Architecture for Play-based Adaptable Service Systems). This thesis is structured into two main parts: Part I – Introduction and Part II – Selected publications. Part I is intended for the reader to get an overview of the publications included in Part II.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Architecture, 2004.
Includes bibliographical references (p. 61-62).
Based on the fact that architecture is, among other things, the crystallization of a mediation among design intentions (function), meaning and contextual constraints (performance), we as designers are obligated to produce morphologically flexible & adaptive design solutions; both during the design process and as a final outcome. In that sense this thesis is an open ended exploration of embedding rational adaptability to object design through computational tools. This thesis will speculate on the advantages of thinking architecture in terms of "adaptation" in an action-reaction fashion, evolving from the seed idea of "motion" in architecture but rather pushing and exploring the potential of digitally designed responsive buildings and the dissection of its methodological approach. Empirically, it will look into some of nature's responsive designs, arguing that buildings can be conceptualized as adaptable living organisms. It will also analyze the role of computational tools and programming languages as meaningful mediums that help designers to better understand, set-up, define and re-define design problems. It will argue that more than an automated provider of an endless number of design solution computers can work as a systematic tool, making us more conscious during the design process.
by Alejandro Zulas.
S.M.

The widespread adoption of embedded computing systems has resulted in the realization of numerous sensing, decision, and control applications with diverse application-specific requirements. However, such embedded systems applications are becoming increasingly difficult to design, simulate, and optimize due to the multitude of interdependent parameters that must be considered to achieve optimal, or near-optimal, performance that meets design constraints. This situation is further exacerbated for data-adaptable embedded systems (DAES) applications due to the dynamic characteristics of the deployment environment and the data streams on which these systems operate. As operating conditions change, these embedded systems must continue to adapt their configuration and composition at runtime in order to meet application requirements. To assist both platform developers and application domain experts, this dissertation presents design and optimization frameworks for the synthesis of runtime adaptable embedded systems. For sensor network applications, we present an initial dynamic profiling and optimization platform that profiles network and sensor node activity to generate optimal node configurations at runtime based on designed-specified application requirements. To support a broader class of DAES applications, we present a modeling and optimization framework that supports the specification of application task flows, data types, and runtime estimation models for the runtime adaptation of task implementations and device mappings. Experimental results for these design and optimization frameworks demonstrate the benefits of dynamic optimization compared to static optimization alternatives. For the presented sensor network and video-based collision avoidance applications, dynamic configurations exhibited improvements of up to 109% and 76%, respectively. Moreover, the performance of the heuristic design space exploration (DSE) algorithms utilized by the runtime optimization frameworks is compared to exhaustive DSE implementations, resulting in speedups of up to 1662X and 544X for the same two applications, respectively.

The need to give educators the ability to enter a particular teaching strategy of their choice into an Intelligent Tutoring System (ITS) and have the ITS respond appropriately to each student has been stated by many researchers. For example, an educator could tell the ITS to keep students within a certain help level ratio (how much help they request), or to introduce a new topic in a particular manner and the ITS simply carries this out at each learning point of interest. Educators could then try new strategies, ones that unaided are impossible to try out in class (such as keeping a student within a help-seeking range) or difficult within an ITS (as the ITS would have to be specially programmed in that way). Current ITSs provide adaptivity to the student at the domain level but not necessarily at the pedagogical level. While a variety of pedagogical strategies have been implemented (e.g. apprenticeship, socratic, practice), there is no system that offers parts or all of these strategies with the ability to choose between them dynamically. In this project, we designed a new framework for an ITS to include multiple, potentially adaptable pedagogical strategies. This was done by breaking up the pedagogical module into separate components. The Pedagogical Strategy Set (PSS) contains all the strategies, written as constraints. The Pedagogical Student Model (PSM) keeps track of which pedagogical strategies were used by each student. Within the ITS, there is still a smaller, separate pedagogical module to deal with domain-specific strategies. The Pedagogical Control Centre (PCC) contains the logic of when and how to use the pedagogical strategies. It gathers its information from the other modules and uses decision logic to trigger strategies. We implemented and evaluated this framework within the context of SQL-Tutor and found that the framework could be used to enter pedagogical strategies, which in turn compared favourably to the original SQL-Tutor. This proof of concept opens up the possibility of the logic and algorithms that could be implemented (e.g. in the PCC) in future ITSs. The PSS is a separate module, written in a different language, independent of ITSs. This could lead to sharing of pedagogical strategies between tutors. Furthermore, students learn differently to each other; this framework allows them to do so.

The aim of this thesis is to track objects on a network of cameras both within [intra) and across (inter) cameras. The algorithms must be adaptable to change and are learnt in a scalable approach. Uncalibrated cameras are used that are patially separated, and therefore tracking must be able to cope with object oclusions, illuminations changes, and gaps between cameras.

Networked services are considered. A networked service is offered by a service system consisting of components, which by their interworkings provide a service in the role of a service provider to users. An adaptable service system is a service system that is able to adapt to changes brought about by users, nodes, capabilities, system performance, and service functionalities. A capability is defined as an inherent property of a node, which is used as a basis to implement a service. This thesis focuses on adaptability aspects related to nodes and capabilities. A service framework is a system for the specification, management, and execution of adaptable service systems. Functionalities of the service framework enable various adaptability types, as follows: capability-related adaptation, functionality-related adaptation, and context-related adaptation. The capability-related adaptation is considered in this thesis. Capability-related adaptation is related to the shortage of capabilities with appropriate logical functionality or the overload or failure of capabilities leading to reduced system performance. This thesis presents a service framework for capability-related adaptation. This service framework consists of a computing architecture, concepts, ontologies, service component models, mechanisms, system architectures, and service execution platforms. The service framework presented is related to TAPAS (Telematics Architecture for Play-based Adaptable Service Systems). The TAPAS concepts and architectures that existed at the beginning of this Ph.D. study are the foundation of this thesis. On the other hand, the research work presented in this thesis has contributed to new TAPAS concepts, ontologies, service component models, mechanisms, system architectures, and service execution platforms. The service framework is classified into six contibutions (C1-C6) as follows: C1: Ontology-based computing architecture C2: Ontologies, models, and representations C3: Policy-based reasoning C4: Autonomic-based model C5: Capability-related adaptation functionality realisation C6: Service execution platforms, prototypes, and simulations Ontology-based computing architecture is an architectural framework for the specification and execution of adaptable service systems that provide any service functionality. Ontologies, models, and representations are applied for the formalisation and representation of the necessary concepts; these are also the basis for the formal definition of the requirements of the capabilities and service component specifications, i.e., the policy and goal specifications. Policy-based reasoning is a support functionality that takes adaptation actions based on flexible and expressive behavioural specifications. The Autonomic-based model is composed of the specification and learning mechanism of the Autonomic Elements that make up an autonomic service system, which is a specialised version of adaptable service systems. Capability-related adaptation functionality realisation defines specific functionalities, interworkings, and structural organisation of the service components that implement the functionalities required for capability-related adaptation. Finally, service execution platforms, prototypes, and simulations provide the validation and evaluation of the remaining contributions

Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2020
Cataloged from the official PDF of thesis.
Includes bibliographical references (pages 102-104).
Unlike traditional impeller trimming, mechanically varying centrifugal pump impellers or volutes can significantly affect pump performance. This thesis explores the potential for performance enhancement by variable impellers as an alternative to, or possibly in conjunction with, popular pump improvement methods like adjustable speed drives (ASD) and permanent impeller trimming. A review of the theory, existing technology, and potential for future advancement creates the foundation for the final assessment and comparison. The methods developed in the thesis are applied to a case study of the United States Navy Arleigh Burke-class guided missile destroyer (DDG-51 class) firemain to propose appropriate impeller trimming to improve system performance, resulting in an annual fuel savings of nearly 10,000 gallons per ship. Although the DDG firemain is used as the primary example throughout the thesis, the review of pump improvement methods could be applied to many Navy, military, or civilian pumping systems. Additionally, the inclusive analysis that the thesis provides may serve as a helpful starting point for future centrifugal pump research and concept development.
by Julia E. Cumming.
S.M.
S.M. Massachusetts Institute of Technology, Department of Mechanical Engineering

This thesis proposes adaptable error detection technique for improving the availability of embedded systems, and in particular Automated Teller Machines (ATMs). The principles associated with immune-inspired techniques are exploited for detecting unforseen errors during run-time, since traditional techniques for error detection are usually limited to the knowledge available during design-time. Furthermore, the adaptable error detectors can be used to predict system failure well before it happens in order to improve overall system availability and/or maintainability. This thesis introduces a framework for realising adaptable error detection (AED), and demonstrates the effectiveness of an artificial immune system (AIS) as a technique for its implementation. Using data obtained from ATMs, the effectiveness of the AIS technique is evaluated based on the efficacy at detecting the incipience of failures. From the early awareness of impending failures, appropriate actions, such as error recovery or operator warning, can be initiated to prevent the deviaton of system's operations from correct service delivery. Alternatively, the foreknowledge of an imminent failure may quicken system repair with the effect that the downtime of the system is reduced and the system's availability is enhanced. The outcome of the investigations showed that the implemented AED could detect the antecedents to failure. The effects of the continuous learning feature were demonstrated in terms of: (1) a continual update of error detectors depending on new run-time bheaviours, and (2) an improvement in the detection capability by anticipating potential failures. Based on these results, I concluded that the adaptable error detection technique proposed is a step towards enhancing the availability of ATMs.

This master thesis is devoted to developing an adaptive control scheme for the well- known Interconnection and Damping Assignment Passivity-Based Control (IDA-PBC) technique. The main objective of this adaptive scheme is to asymptotically stabilize a class of Underactuated Mechanical Systems (UMSs) in the presence of uncertainties (not necessarily matched). This class of UMSs is characterized by the solvability of the Partial Differential Equation (PDE) resulting from the IDA-PBC technique. Two propositions are stated in this work to design the adaptive IDA-PBC. One of the main properties of these propositions is that even though the parameter estimation conver- gence is not guaranteed, the adaptive IDA-PBC achieves asymptotic stabilization. To illustrate the effectiveness of these propositions, this work performs simulations of the Inertia Wheel Inverted Pendulum (IWIP) system, considering a time-dependent input disturbance, a type of physical damping, i.e., friction (not considered in the standard IDA-PBC methodology), and parameter uncertainties in the system (e.g., inertia).
Tesis

Increasing global competition, market uncertainties and high product variance are a few of the factors posing challenges to the existing manufacturing industry. Having a quick response to market fluctuations and adapting to changing customer demands while maintaining shorter lead times and low costs are a few of the major challenges. The main focus of this thesis is on Evolvable Production Systems, which is one of the promising solutions to deal with the emerging manufacturing challenges by changing the conventional manufacturing systems towards a more flexible, intelligent and adaptable approach. Although promising, further research is needed in several directions for a wider industrial acceptance of EPS. The directions include but are not limited to methodological aspects, tool support, etc. throughout the development lifecycle. This thesis aims to provide a basis for a holistic model-based development methodology for evolvable production systems. One of the main contributionsof this work is the identification of major architectural elements (i.e stakeholders,concerns, viewpoints and views) and their dependencies on each other.This work shall serve as a basis for establishing a well-defined architectural framework for EPS. The second important contribution of this thesis is the development of a domain specific modeling language (EPS- DSL) based on the existing EPS ontology. The DSM platform does not only store the domain knowledge in the form of models but also provides support for the re-use of these models, i.e. enables utilization of the domain ontology during system development. Moreover, the automatic code generation support for the module library presented in this work, significantly reduces the risks of information discrepancies when transferring data from one abstraction level to another. The existing EPS ontology is also evaluated from a holistic perspective and resulted in contributing a few improvement suggestions for achieving a seamless model-based development approach. Evaluation of Simulink/SimEvents as a modeling and simulation tool for EPS is the third main contribution of this thesis. One of the main advantages of evaluating this tool for EPS is the opportunity to analyze the complete system behavior on a single modeling platform. The integration of agent-based system behavior (discrete event) with dynamic system behavior (continuous & discrete time) provides a holistic modeling approach and implies less information inconsistencies.

QC 20160429

This thesis investigates the use of static, adaptive, adaptable and mixed-initiative approaches to the personalisation of content and graphical user interfaces (GUIs). This empirical study consisted of three experimental phases. The first examined the use of static, adaptive, adaptable and mixed-initiative approaches to web content. More specifically, it measured the usability (efficiency, frequency of error occurrence, effectiveness and satisfaction) of an e-commerce website. The experiment was conducted with 60 subjects and was tested empirically by four independent groups (15 subjects each). The second experiment examined the use of adaptive, adaptable and mixed-initiative approaches to GUIs. More specifically, it measured the usability (efficiency, frequency of error occurrence, effectiveness and satisfaction) in GUI control structures (menus). In addition, it investigated empirically the effects of content size on five different personalised menu types. In order to carry out this comparative investigation, two independent experiments were conducted, on small menus (17 items) and large ones (29 items) respectively. The experiment was conducted with 60 subjects and was tested empirically by four independent groups (15 subjects each). The third experiment was conducted with 40 subjects and was tested empirically by four dependent groups (5 subjects each). The aim of the third experiment was to mitigate the drawbacks of the adaptive, adaptable and mixedinitiative approaches, to improve their performance and to increase their usability by using multimodal auditory solutions (speech, earcons and auditory icons). The results indicate that the size of content affects the usability of personalised approaches. In other words, as the size of content increases, so does the need of the adaptive and mixed-initiative approaches, whereas that of the adaptable approach decreases. A set of empirically derived guidelines were also produced to assist designers with the use of adaptive, adaptable and mixed-initiative approaches to web content and GUI control structure.

This thesis investigates the use of static, adaptive, adaptable and mixed-initiative approaches to the personalisation of content and graphical user interfaces (GUIs). This empirical study consisted of three experimental phases. The first examined the use of static, adaptive, adaptable and mixed-initiative approaches to web content. More specifically, it measured the usability (efficiency, frequency of error occurrence, effectiveness and satisfaction) of an e-commerce website. The experiment was conducted with 60 subjects and was tested empirically by four independent groups (15 subjects each). The second experiment examined the use of adaptive, adaptable and mixed-initiative approaches to GUIs. More specifically, it measured the usability (efficiency, frequency of error occurrence, effectiveness and satisfaction) in GUI control structures (menus). In addition, it investigated empirically the effects of content size on five different personalised menu types. In order to carry out this comparative investigation, two independent experiments were conducted, on small menus (17 items) and large ones (29 items) respectively. The experiment was conducted with 60 subjects and was tested empirically by four independent groups (15 subjects each). The third experiment was conducted with 40 subjects and was tested empirically by four dependent groups (5 subjects each). The aim of the third experiment was to mitigate the drawbacks of the adaptive, adaptable and mixedinitiative approaches, to improve their performance and to increase their usability by using multimodal auditory solutions (speech, earcons and auditory icons). The results indicate that the size of content affects the usability of personalised approaches. In other words, as the size of content increases, so does the need of the adaptive and mixed-initiative approaches, whereas that of the adaptable approach decreases. A set of empirically derived guidelines were also produced to assist designers with the use of adaptive, adaptable and mixed-initiative approaches to web content and GUI control structure.

The main goal of this thesis is the creation o f the tool agent-oriented programming tool AJA. AJA is the acronym for Adaptable Java Agents. AJA consists o f two programming languages:- A higher-level language used for the description of the main agent parts. This language is called HADL, which is the acronym for Higher Agent Definition Language.- A lower-level language used for the programming o f the agent parts defined in HADL. This language is called Java+. It is actually Java enriched with the constructs for accessing higher-level agent parts defined in HADL.A translator from AJA to Java is implemented in the practical part o f the thesis. AJA agents have the following features: - Agent communicates with other agents using a construct called negotiation. The messages sent can be encrypted or digitally signed in order to ensure the security of the system. - Agent possesses adaptable  parameters and neural nets that adapt themselves when the environment changes.- Agent has reflexes, which are the reactive component o f the agent architecture.- Agent can perform its actions parallel. Actions execution is synchronized.- Agent is accessible via Internet, because it acts as a simple HTTP server. People can use this way to communicate with an agent.- Agent has Java Swing based graphical user interface. Its owner uses this interface to communicate with the agent.- Because o f the fact that Java-i- language extends Java, it is possible to use all useful Java features in the implementation o f AJA agents (e.g. JDBC for the database access). The thesis also presents an original approach of integrating artificial intelligence techniques, such as neural nets, with a programming language. Having the artificial intelligence components as a part of the programming language runtime environment makes their use straightforward. A programmer uses the language constructs that are implemented using the artificial intelligencewithout the need for understanding their background and theory.The thesis contains eight chapters and three appendixes. In the first chapter, an overview of agents and multi-agent systems is given. The second chapter surveys existing agent-oriented programming languages and tools. The third chapter introduces AJA and describes the architecture of AJA agents. The syntax and semantics o f AJA languages HADL and Java+ is described in the fourth chapter. The fifth chapter presents adaptable AJA constructs in more details. To demonstrate and test the created tool, a case-study multi-agent system has been implemented in AJA. There are four personal digital assistant agents in the system. The sixth chapter describes the example agents and positively evaluates the tool. In the seventh chapter the related work and tools are analyzed and compared to AJA. The last chapter concludes the thesis. The first appendix describes the implementation details of the AJA to Java translator. The second appendix is a guide for the installation and usage of the implemented AJA to Java translator. Finally, the thirdappendix describes step by step how to translate, compile, run, and use the example agents. The thesis contains many references, which include almost all the most important and the most actual papers in the field. The reference list can be found at the end o f the thesis.
Glavni doprinos doktorske teze je napravljeni alat za programiranje agenata AJA . AJA - Adaptabilni Java Agenti je jezički alat za programsku implementaciju agenata Sastoji se od dva programska jezika:- Jezik višeg nivoa kojim se opisuju glavne kom ponente agenta. Ovaj jezik se naziva HADL - Higher Agent Definition Language.- Jezik nižeg nivoa koji služi za implementaciju pojedinih komponenti agenta specificiranih HADL jezikom . Ovaj jezik se najava Java+, jer je on zapravo programski jezik Java obogaćen konstrukcijama pomoću kojih je moguće pristupati komponentama agenta, definisanim u jezik u HADL.AJA agent poseduje sledeće osobine:- Sigurna kom unikacija sa drugim A JA agentim a koristeći mehanizam pregovaranja, šifrovanje i digitalno potpisivanje poruka.- Mogućnost adaptiranja na promene u okruženju u kom se nalazi, koristeći neuralne mreže i adaptabilne parametre.- Reaktivnost zasnovana n a kom ponenti zvanoj refleks.- Paralelno izvršavanje akcija agenta u z njihovu internu sinhronizaciju.- D ostupnost agenta preko Interneta. Agent se ponaša kao jednostavan HTTP server. Na ovaj način se drugim osobama omogućuje da komuniciraju sa agentom .- G rafički korisnički interfejs zasnovan n a Java Swing tehnologiji- Pošto se u program iranju agenta koristi Java+, moguće je uposliti sve pogodnosti Jave, kao što su na primer pristup bazama podataka koristeći JDBC , rad sa multimedijalnim sadržajem , itd.U tezi je predstavljen i originalni pristup integrisanja tehnika veštačke inteligencije sa program skim jezikom . U građujući kom ponente veštačke inteligencije u izvršnu okolinu je z ik a čini n jihovo korišćenje veom a jednostavnim . Programer ne mora da bude ekspert iz veštačke inteligencije a da pri tome koristi konstrukcije jezika koje su implementirane pomoću veštačke inteligencije. AJA specifikacija agenta se sastoji od HADL i Java+ delova. U tezi je implementiran prevodioc kojim se A JA specifikacija prevodi u skup klasa programskog jezika Java. Implementiran je i jedan multi-agentski sistem kojim se praktično pokazuje korišćenje i mogućnosti napravljenog alata D oktorska teza sadrži i detaljan pregled oblasti o agentskpj m etodologiji. O n a kruniše višegodišnji rad kandidata i njegovog mentora u ovoj sve značajnijoj oblasti računarstva.Teza sadrži o sam glava i tri dodatka. U prvoj glavi se opisuje oblast agenata i m ulti-agentskih sistem a. Pregled postojećih agentskih program skih jezik a i alata se daje u drugoj glavi. O pis A JA agenata i njihove arhitekture je dat u trećoj glavi teze. Četvrta glava se bavi sintaksom i sem antikom oba A JA jezika: H A D L -a i Jave+. Adaptabilni elem enti A JA agenata se opisuju u petoj glavi. U šestoj glavi je opisan m ulti-agentski sistem koji j e ujed n o i prim er prim ene A JA alata. A JA se sa drugim postojećim agentskim alatim a upoređuje u sedm oj glavi. Osma glava sadrži zaključak. N a kraju se u tri dodatka detaljno opisuju im plem entacija prevodioca A JA -e u Javu, instalacija prevodioca i korišćenje napravljenog m ulti-agentskog sistema respektivno. U doktorskom radu su korišćene i navedene brojne reference kojim a su obuhvaćeni gotovo svi najznačajniji i najaktuelniji radovi iz oblasti multi-agentskih sistema. Lista referenci je navedena na kraju teze.

GENERATING USER-CENTRIC DYNAMIC AND ADAPTABLE KNOWLEDGE MODELS FOR WORLD WIDE WEB By LEI LI JUNE, 2007 Committee Chair: Dr. Vijay Vaishnavi Major Department: Computer Information Systems In the current Internet age, more and more people, organizations, and businesses access the web to share and search for information. A web-based resource is often organized and presented based on its knowledge models (categorization structures). The static and inflexible knowledge models of web-based resources have become a major challenge for web users to successfully use and understand the information on the web. In this dissertation, I propose a research approach to generate user-centric dynamic and adaptable knowledge models for web-based resources. The user-centric feature means that a knowledge model is created based on a web user specified perspective for a web resource and that the user can provide feedback on the model building process. The dynamic feature means the knowledge models are built on the fly. The adaptable feature means the web user can have control of the user adaptation process by specifying his or her perspective for the web resource of interest. In this study, I apply a design science paradigm and follow the General Design Cycle (Vaishnavi and Kuechler 2004) during the course of research. A research prototype, Semantic Facilitator TM SM V2.0, has been implemented based on the proposed approach. A simulation-based experimentation is used to evaluate the research prototype. The experimental results show that the proposed research approach can effectively and efficiently create knowledge models on the fly based on a web user preferred perspective for the web resource. I found that incorporating user feedback into the modeling building process can greatly improve the quality of the knowledge models. At the end of the dissertation, I discuss the limitations and future directions of this research.

Abstract The development of mobile and ubiquitous computing has recently been rapid. One of the most promising research and development fields has been location-aware services. These services are challenging as they require a lot of resources for generating maps from spatial data and for visualizing temporary data gathered from the environment. Applying location-awareness and ubiquitous computing in the industry is currently under intensive research and development activities especially because of signs of promising new business opportunities. This thesis studies the development and evaluation of a location-aware system platform called Locawe designed for indoor and outdoor conditions. This decentralized middleware-based platform has been developed at CENTRIA Research and Development, Ylivieska. The main objectives of this research have been primarily to study and develop new ubiquitous features for the Locawe platform with various software and hardware combinations. In addition, during these studies gathered experiences have been used in order to design new versions of the Locawe architecture. These ubiquitous features, covering the use of GPS, RFID and WSAN technologies, have been tested in five field experiments, one laboratory experiment and several industrial pilots. In these evaluations, the author has considered what software and hardware alternatives are feasible and appropriate for improving the newly developed features in the Locawe platform. These features have been evaluated from usability, visualization and communication techniques perspective. As a result the author presents in this thesis main characteristics in location-aware system development from system layers, ubiquitous computing, mobility, and restrictions perspective. The author also suggests that the architeture presented in this thesis enables location-aware system development in indoor and outdoor conditions. With respect of state-of-the-art platforms, the Locawe platform is, at the moment, in some sense unique, although only as a research prototype. This platform combines two approaches, namely research on location platforms, and research on geosensor networks or smart environments. In addition, this platform gives one answer how RFID or WSAN technologies could be integrated under one framework together with mobile devices. Finally, the author also proposes that the research and development approach presented in this thesis can be applied successfully in research and development organizations specialized in applied research
Tiivistelmä Mobiilin ja sulautetun tietotekniikan kehitys on ollut viime aikoina nopeaa. Yksi lupaavimmista tutkimus- ja kehityskohteista on ollut paikkatietoiset palvelut. Näiden palveluiden kehittäminen on varsin haasteellista, koska kehittämistyö vaatii runsaasti resursseja sekä karttojen generoimisessa paikkatietoaineistoista että ympäristöstä kerättävän väliaikaisen tiedon visualisoinnissa. Paikkatietoisten sovellusten ja sulautetun tietotekniikan soveltaminen teollisuudessa on aktiivisen tutkimus- ja kehittämistoiminnan keskiössä, koska näköpiirissä on selvästi uusia lupaavia liiketoimintamahdollisuuksia. Tässä väitöskirjassa keskitytään Locawe-nimisen paikkatietoisen ohjelmistoalustan kehittämisen ja arvioinnin raportointiin. Locawe-alusta on suunniteltu sekä sisä- että ulko-olosuhteisiin. Tämä hajautettu väliohjelmistopohjainen alusta on kehitetty CENTRIA Tutkimus ja kehityksen Ylivieskan yksikössä. Väitöskirjan tavoitteena on ollut ensisijaisesti tutkia ja kehittää uusia, sulautettua tietotekniikkaa hyödyntäviä ominaisuuksia Locawe-alustaan hyödyntäen erilaisia ohjelmisto- ja laitteistokombinaatioita. Väitöskirjaan liittyvän tutkimustyön aikana käyttäjiltä on useaan otteeseen kerätty käyttökokemuksia. Kokemuksia on hyödynnetty Locawe-arkkitehtuurin seuraavien versioiden suunnittelussa. Uusia, sulautettua tietotekniikkaa hyödyntäviä ominaisuuksia on testattu kaikkiaan viidessä kenttätestissä, yhdessä laboratoriotestissä sekä useissa teollisissa piloteissa. Ominaisuuksien toteuttamisessa käytettiin GPS-, RFID- ja WSAN-teknologioita. Testeissä kirjoittaja arvioi, minkälaiset ohjelmisto- ja laitteistovaihtoehdot ovat toteuttamiskelpoisimpia ja soveliaimpia uusien ominaisuuksien kehittämiseksi Locawe-alustaan. Ominaisuuksia on arvioitu käytettävyyden, visualisoinnin ja viestintätekniikoiden näkökulmista. Tutkimustyön tuloksena kirjoittaja esittelee väitöskirjassa paikkatietoisten järjestelmien kehittämiseen liittyviä ominaispiirteitä järjestelmätasojen, sulautetun tietotekniikan, mobiliteetin ja rajoitteiden näkökulmista. Lisäksi kirjoittaja esittää väitöskirjassa arkkitehtuurin, joka mahdollistaa paikkatietoisen järjestelmän kehittämisen soveltuen niin sisä- kuin ulko-olosuhteisiin. Huomioiden paikkatietoisten alustojen tason maailmanlaajuisesti väitöskirjassa kuvattu Locawe-alusta on tutkimusprototyyppinäkin tällä hetkellä tietyssä määrin ainutlaatuinen. Alustan tutkimisessa on nimittäin keskitytty sekä paikkatietoisten alustojen että geosensoriverkkojen ja älykkäiden ympäristöjen tutkimiseen. Lisäksi Locawe-alusta tarjoaa yhden ratkaisun RFID ja WSAN teknologioiden integrointiin yhdeksi kehykseksi yhdessä mobiililaitteiden kanssa. Lopuksi kirjoittaja esittää, että väitöskirjassa esitetty tutkimus- ja kehittämistoiminnan lähestymistapaa voidaan soveltaa vastaavissa tutkimusorganisaatioissa kuin CENTRIA

This thesis aims to define software and hardware mechanisms helping in the management the Heterogeneous and dynamically Reconfigurable Systems-on-Chip (HRSoC). The heterogeneity is due to the presence of general processing units and reconfigurable IPs. Our objective is to provide to an application developer an abstracted view of this heterogeneity, regarding the task mapping on the available processing elements. First, we homogenize the user interface defining a hardware thread model. Then, we pursue with the homogenization of the hardware threads management. We implemented OS services permitting to save and restore a hardware thread context. Conception tools have also been developed in order to overcome the relocation issue. The last step consisted in extending the access to the distributed OS services to every thread running on the platform. This access is provided independently from the thread location and is is realized implementing the MRAPI API. With these three steps, we build a solid basis to, in future work, provide to the developer, a conception flow dedicated to HRSoC allowing to perform precise architectural space explorations. Finally, to validate these mechanisms, we realize a demonstration platform on a Virtex 5 FPGA running a dynamic tracking application.

The combination of graphical user interface (GUI) and usability evaluation presents an advantage to mastering every piece of software and ensuring perfect quality of work. The increasing demand for online learning is becoming more important, both individually and academically. This thesis introduces and describes an empirical study to investigate and compare how vocabulary can be learned by using different interactive approaches; specifically, a static learning website (with straightforward words and meanings), an adaptable learning website (allowing the user to choose a learning method), an adaptive learning website (a system-chosen way of learning), and a mixed-initiative (mixing approaches and techniques). The purpose of this study is to explore and determine the effects of these approaches in learning vocabu-lary achievement to enhance vocabulary learning for non-English speakers. The par-ticipants were Arabic speakers. The three levels of vocabulary learning activities were categorised as easy, medium, and hard. The independent variables (IVs) were controlled during the experiment to ensure consistency and were as follows: tasks, learning effects, and time. The dependent variables (DVs) were learning vocabulary achievements and scores. Two aims were explored in relation to the effects of these approaches to achievement. The first related to learning vocabularies for non-English speakers tackling the difficulties of the English language and the second related to studying system usability of learning English vocabulary in terms of usability measures (efficiency, frequency of error occurrence, effectiveness, and satisfaction). For this purpose, a vocabulary-learning language website was designed, implement-ed, and tested empirically. To fulfill these requirements, it was first necessary to measure two usability components (efficiency and effectiveness) with a within-subject design of n = 24 subjects recruited and, for users’ satisfaction, a between-subject design of n = 99 subjects recruited, while investigating satisfaction with a system usability scale (SUS) survey. The results and data analysis were described. Overall, the results shown were all satisfactory.

Unfortunately, the global conventional fuels in reserves are running out while the world energy consumption is increasing unruly. Therefore, innovative methods for providing sustainable heating and cooling through thermal energy storage (TES) have gained increasing attention. This study presents a numerical and experimental investigation of near surface ground energy systems including the use of adaptable insulation layers. The experimental set up involves the development of an innovative technique that is proposed to regulate the transfer of heat energy to the storage regions of the soil mass. Furthermore, a theoretical framework to represent the transient processes of such systems was developed and 1D and 2D numerical models were established to simulate ground energy system behaviour. The finite element method was utilised for spatial discretization and the finite difference method for time-stepping. The resulting model took into account conductive and convective heat transfer between the fluid inside pipe heat exchangers and the surrounding soil. Key additions were introduced to the recent model work which allowed it to take into account surface snow and ground freezing presence in the system, the amount of thermal energy available in the system and the ability to represent porous layer thermal properties of a multi layered system through considering its components (i.e. air, water and solids particles). The proposed new experimental setup was used to investigate the practical implementation of adaptable insulation layers with the experimental data then used to validate the numerical model. Further validation of the modelling of the surface snow and ground freezing was achieved via comparison against an experimental case study performed by others. In the analysis performed, particular attention was given to the energy balance at the soil surface and its impact on the performance of thermal energy storage devices in shallow regions of the ground. Additionally, the developed models were applied to explore the use of the adaptable insulation layer in different systems in comparison to typical designs. Three case scenarios were chosen to represent different type of systems, a comparisons analysis was then introduced which shows the potential effectiveness of using the adaptable insulation layer.

The purpose of this study was to develop a list of usability guidelines, i.e. a usability checklist, which can assist in evaluating the usability of Massive Open Online Courses (MOOCs) user interfaces. Interviews were conducted to help understand their context of use and to find design focus points for the evaluation of MOOCs interface. These design focus points were then inspected for usability issues with Jakob Nielsen’s usability inspection method - heuristic evaluation - using author’s own set of 10 usability heuristics. The study reveals two main findings. Firstly, the context of use of MOOCs differs from a regular university course in the manner of how users perceive and approach them. And secondly, the usability checklist has to be adaptable and up-to-date in order to support the constant change of context of use of MOOCs. The combination of both findings is what makes this study not just another checklist, but a valid contribution to the understanding of MOOCs and the research field in HCI.

Runtime dynamic reconfiguration of field-programmable gate arrays (FPGAs) and devices incorporating microprocessors and FPGA has been successfully utilized to increase performance and reduce power consumption. While previous methods have been successful, they typically do not consider the runtime behavior of the application that can be significantly affected by variations in data inputs, user interactions, and environmental conditions. In this dissertation, we present a dynamically reconfigurable system and design methodology that optimizes performance and power consumption by determining which coprocessors to implement with an FPGA based upon the current application behavior.For dynamically reconfigurable systems, in which the selection of hardware coprocessors to implement within the FPGA is determined at runtime, online estimation methods are essential to evaluate the performance and power consumption impact of the hardware coprocessor selection. We present a base profile assisted online system-level performance and power estimation framework for estimating the speedup and power consumption of dynamically reconfigurable embedded systems.Importantly though, complex interactions between multiple application tasks, non-deterministic execution behavior, and effects of operating system scheduling introduce significant challenges. To address these, we further present an adaptive online performance and power estimation framework suing kernel speedup coefficient adaptation that monitors and adapts the changing application and system behavior for multitasked applications. By exhaustively examining predefined voltage and frequency settings for the microprocessor and hardware kernels, the potential speedup and power reduction can be effectively estimated for each configuration and voltage/frequency settings. These estimates can be utilized to determine the optimal system configuration. At the same time, the kernel speedup coefficients for each kernel can be dynamically updated to account for the difference between the estimated and actual performance measured at runtime.Finally, in order to quickly determine kernel selection and voltage and frequency settlings, we present an efficient, online heuristic performance and power estimation framework that significantly decreases execution time at the cost of a small increase in power consumption. This online heuristic estimation framework achieves significant power reduction compared to software only implementation without performance degradation.

Many digital logic applications can take advantage of the reconfiguration capability of Field Programmable Gate Arrays (FPGAs) to dynamically patch design flaws, recover from faults, or time-multiplex between functions. Partial reconfiguration is the process by which a user modifies one or more modules residing on the FPGA device independently of the others. Partial Reconfiguration reduces the granularity of reconfiguration to be a set of columns or rectangular region of the device. Decreasing the granularity of reconfiguration results in reduced configuration filesizes and, thus, reduced configuration times. When compared to one bitstream of a non-partial reconfiguration implementation, smaller modules resulting in smaller bitstream filesizes allow an FPGA to implement many more hardware configurations with greater speed under similar storage requirements. To realize the benefits of partial reconfiguration in a wider range of applications, this thesis begins with a survey of FPGA fault-handling methods, which are compared using performance-based metrics. Performance analysis of the Genetic Algorithm (GA) Offline Recovery method is investigated and candidate solutions provided by the GA are partitioned by age to improve its efficiency. Parameters of this aging technique are optimized to increase the occurrence rate of complete repairs. Continuing the discussion of partial reconfiguration, the thesis develops a case-study application that implements one partial reconfiguration module to demonstrate the functionality and benefits of time multiplexing and reveal the improved efficiencies of the latest large-capacity FPGA architectures. The number of active partial reconfiguration modules implemented on a single FPGA device is increased from one to eight to implement a dynamic video-processing architecture for Discrete Cosine Transform and Motion Estimation functions to demonstrate a 55-fold reduction in bitstream storage requirements thus improving partial reconfiguration capability.
M.S.Cp.E.
School of Electrical Engineering and Computer Science
Engineering and Computer Science
Computer Engineering MSCpE

In this dissertation, neural networks are designed to effectively model static non-linear aeroelastic problems in adaptive structures and linear dynamic aeroelastic systems with time varying stiffness. The use of adaptive materials in aircraft wings allows for the change of the contour or the configuration of a wing (morphing) in flight. The use of smart materials, to accomplish these deformations, can imply that the stiffness of the wing with a morphing contour changes as the contour changes. For a rapidly oscillating body in a fluid field, continuously adapting structural parameters may render the wing to behave as a time variant system. Even the internal spars/ribs of the aircraft wing which define the wing stiffness can be made adaptive, that is, their stiffness can be made to vary with time. The immediate effect on the structural dynamics of the wing, is that, the wing motion is governed by a differential equation with time varying coefficients. The study of this concept of a time varying torsional stiffness, made possible by the use of active materials and adaptive spars, in the dynamic aeroelastic behavior of an adaptable airfoil is performed here. A time marching technique is developed for solving linear structural dynamic problems with time-varying parameters. This time-marching technique borrows from the concept of Time-Finite Elements in the sense that for each time interval considered in the time-marching, an analytical solution is obtained. The analytical solution for each time interval is in the form of a matrix exponential and hence this technique is termed as Matrix Exponential time marching. Using this time marching technique, Artificial Neural Networks can be trained to represent the dynamic behavior of any linearly time varying system. In order to extend this methodology to dynamic aeroelasticity, it is also necessary to model the unsteady aerodynamic loads over an airfoil. Accordingly, an unsteady aerodynamic panel method is developed using a distributed set of doublet panels over the surface of the airfoil and along its wake. When the aerodynamic loads predicted by this panel method are made available to the Matrix Exponential time marching scheme for every time interval, a dynamic aeroelastic solver for a time varying aeroelastic system is obtained. This solver is now used to train an array of neural networks to represent the response of this two dimensional aeroelastic system with a time varying torsional stiffness. These neural networks are developed into a control system for flutter suppression. Another type of aeroelastic problem of an adaptive structure that is investigated here is the shape control of an adaptive bump situated on the leading edge of an airfoil. Such a bump is useful in achieving flow separation control for lateral directional maneuverability of the aircraft. Since actuators are being used to create this bump on the wing surface, the energy required to do so needs to be minimized. The adverse pressure drag as a result of this bump needs to be controlled so that the loss in lift over the wing is made minimal. The design of such a "spoiler bump" on the surface of the airfoil is an optimization problem of maximizing pressure drag due to flow separation while minimizing the loss in lift and energy required to deform the bump. One neural network is trained using the CFD code FLUENT to represent the aerodynamic loading over the bump. A second neural network is trained for calculating the actuator loads, bump displacement and lift, drag forces over the airfoil using the finite element solver, ANSYS and the previously trained neural network. This non-linear aeroelastic model of the deforming bump on an airfoil surface using neural networks can serve as a fore-runner for other non-linear aeroelastic problems. This work enhances the traditional aeroelastic modeling by introducing time varying parameters in the differential equations of motion. It investigates the calculation of non-conservative aerodynamic loads on morphing contours and the resulting structural deformation for non-linear aeroelastic problems through the use of neural networks. Geometric modeling of morphing contours is also addressed.
Ph. D.

The increasing use of model-driven software development has renewed emphasis on using domain-specific models during application development. More specifically, there has been emphasis on using domain-specific modeling languages (DSMLs) to capture user-specified requirements when creating applications. The current approach to realizing these applications is to translate DSML models into source code using several model-to-model and model-to-code transformations. This approach is still dependent on the underlying source code representation and only raises the level of abstraction during development. Experience has shown that developers will many times be required to manually modify the generated source code, which can be error-prone and time consuming. An alternative to the aforementioned approach involves using an interpreted domain-specific modeling language (i-DSML) whose models can be directly executed using a Domain Specific Virtual Machine (DSVM). Direct execution of i-DSML models require a semantically rich platform that reduces the gap between the application models and the underlying services required to realize the application. One layer in this platform is the domain-specific middleware that is responsible for the management and delivery of services in the specific domain. In this dissertation, we investigated the problem of designing the domain-specific middleware of the DSVM to facilitate the bifurcation of the semantics of the domain and the model of execution (MoE) while supporting runtime adaptation and validation. We approached our investigation by seeking solutions to the following sub-problems: (1) How can the domain-specific knowledge (DSK) semantics be separated from the MoE for a given domain? (2) How do we define a generic model of execution (GMoE) of the middleware so that it is adaptable and realizes DSK operations to support delivery of services? (3) How do we validate the realization of DSK operations at runtime? Our research into the domain-specific middleware was done using an i-DSML for the user-centric communication domain, Communication Modeling Language (CML), and for microgrid energy management domain, Microgrid Modeling Language (MGridML). We have successfully developed a methodology to separate the DSK and GMoE of the middleware of a DSVM that supports specialization for a given domain, and is able to perform adaptation and validation at runtime.

International Telemetering Conference Proceedings / October 25-28, 1999 / Riviera Hotel and Convention Center, Las Vegas, Nevada
Emerging technologies in the field of "Test & Measurement" have recently enabled the development of the Rapidly Adaptable Instrumentation Tester (RAIT). Based on software developed with LabVIEW®, the RAIT design enables quick reconfiguration to test and calibrate a wide variety of telemetry systems. The consequences of inadequate testing could be devastating if a telemetry system were to fail during an expensive flight mission. Supporting both open-bench testing as well as automated test sequences, the RAIT has significantly lowered total time required to test and calibrate a system. This has resulted in an overall lower per unit testing cost than has been achievable in the past.

The growth in the number of wireless devices and applications underscores the need for characterizing and mitigating interference induced problems such as distortion and blocking. A typical interference scenario involves the detection of a small amplitude signal of interest (SOI) in the presence of a large amplitude interfering signal; it is desirable to attenuate the interfering signal while preserving the integrity of SOI and an appropriate dynamic range. If the frequency of the interfering signal varies or is unknown, an adaptive notch function must be applied in order to maintain adequate attenuation. This work explores the performance space of a phase cancellation technique used in implementing the desired notch function for communication systems in the 1-3 GHz frequency range. A system level model constructed with MATLAB and related simulation results assist in building the theoretical foundation for setting performance bounds on the implemented solution and deriving hardware specifications for the RF notch subsystem devices. Simulations and measurements are presented for a Low Noise Amplifer (LNA), voltage variable attenuators, bandpass filters and phase shifters. Ultimately, full system tests provide a measure of merit for this work as well as invaluable lessons learned. The emphasis of this project is the on-wafer LNA measurements, dependence of IC system performance on mismatches and overall system performance tests. Where possible, predictions are plotted alongside measured data. The reasonable match between the two validates system and component models and more than compensates for the painstaking modeling efforts. Most importantly, using the signal to interferer ratio (SIR) as a figure of merit, experimental results demonstrate up to 58 dB of SIR improvement. This number represents a remarkable advancement in interference rejection at RF or microwave frequencies.

У овом раду приказанa je анализа резултата истраживања,постојећих техничких решења и искустава из IT индустрије упојединачним и комбинованим областима: дистрибуираниразвој софтвера и управљање софтверским пројектима удистрибуираном окружењу, метричка заснованост управљањасофтверским пројектима, адатибилност у управљању агилнимсофтверским пројектима, адаптибилни дистрибуиранихинформациони системи.Предложен је функционално-технолошки теоријски моделсофтверске подршке адаптибилног дистрибуираногинформационог система за подршку управљању реализацијомсофтверских пројеката. Предложени су приступи у процесуразвоја система у оквиру креирања модела софтверскихфункција и концептуалног модела података. Предложени суметрички модели за евалуацију артефакта у развоју софтвера уобласти развоја информационих система, као и метричкимодели за процену трајања пројекта и мониторинг успехапроцеса у дистрибуираном развоју софтвера.Описана је имплементација почетног прототипа система(реализованог као web апликација www.it-project.rs), у оквируког су реализоване основне функције система. Извршена суемпиријска истраживања могућности коришћења прототипасистема у настави и професионалном усавршавању студената ианализа резултата пробног коришћења прототипа од стране ИТкадрова уз пратеће анкетирање. Извршена је бенчмаркинганализа најчешће коришћених расположивих алата издвојениханкетирањем. Извршена је анализа резултата емпиријскихистраживања у односу на ефикасност примене прототипа.Извршена је анализа резултата примене метричких модела заевалуацију артефакта развоја софтвера, мониторинг успехапроцеса и процену трајања пројекта у делу процесаимплементације софтвера. Реализовано је унапређењепрототипа у односу на претходно дефинисане захтевефункционално-технолошког теоријског модела система.
U ovom radu prikazana je analiza rezultata istraživanja,postojećih tehničkih rešenja i iskustava iz IT industrije upojedinačnim i kombinovanim oblastima: distribuiranirazvoj softvera i upravljanje softverskim projektima udistribuiranom okruženju, metrička zasnovanost upravljanjasoftverskim projektima, adatibilnost u upravljanju agilnimsoftverskim projektima, adaptibilni distribuiranihinformacioni sistemi.Predložen je funkcionalno-tehnološki teorijski modelsoftverske podrške adaptibilnog distribuiranoginformacionog sistema za podršku upravljanju realizacijomsoftverskih projekata. Predloženi su pristupi u procesurazvoja sistema u okviru kreiranja modela softverskihfunkcija i konceptualnog modela podataka. Predloženi sumetrički modeli za evaluaciju artefakta u razvoju softvera uoblasti razvoja informacionih sistema, kao i metričkimodeli za procenu trajanja projekta i monitoring uspehaprocesa u distribuiranom razvoju softvera.Opisana je implementacija početnog prototipa sistema(realizovanog kao web aplikacija www.it-project.rs), u okvirukog su realizovane osnovne funkcije sistema. Izvršena suempirijska istraživanja mogućnosti korišćenja prototipasistema u nastavi i profesionalnom usavršavanju studenata ianaliza rezultata probnog korišćenja prototipa od strane ITkadrova uz prateće anketiranje. Izvršena je benčmarkinganaliza najčešće korišćenih raspoloživih alata izdvojenihanketiranjem. Izvršena je analiza rezultata empirijskihistraživanja u odnosu na efikasnost primene prototipa.Izvršena je analiza rezultata primene metričkih modela zaevaluaciju artefakta razvoja softvera, monitoring uspehaprocesa i procenu trajanja projekta u delu procesaimplementacije softvera. Realizovano je unapređenjeprototipa u odnosu na prethodno definisane zahtevefunkcionalno-tehnološkog teorijskog modela sistema.
Тhis work presents analysis of research results, existingtechnical solutions and experiences from IT industry inseparate and combined fields of: distributed softwaredevelopment, software project management in distributedenvironment, metric-based software project management,adaptability in management of agile software projects, aswell in the field of adaptable distributed informationsystems.Functional-technological theoretical model of softwaresupport to adaptable distributed information system forsoftware projects realization has been proposed. Approachesto creating software functions model and conceptual datamodel within the process of the system development wereproposed. Metric models for evaluation of artefacts createdin software development within information systemdevelopment, as well as metric models for project durationestimation and monitoring of process success in distributedsoftware development were proposed.Implementation of initial prototype of the system(developed as web application www.it-project.rs), thatincludes basic functions, was described. Empirical researchon possibilities for using prototype in educationalenvironment and professional improvement of students, aswell as analysis of results from using the prototype by ITprofessionals, with additional questionnaire, has beenconducted. Benchmarking analysis of most frequently usedavailable tools, extracted from questionnaire results, hasbeen performed. Analysis of empirical research results hasbeen performed in the context of prototype using efficiency.Analysis of results in metric models application in evaluationof software development artefacts, process successmonitoring and project duration estimation, in softwareimplementation process part, has been conducted.Improvement of prototype has been implemented accordingto requirements defined in previously proposed functionaltechnologicaltheoretical model of the system.

Over the last decades, the worldwide increase in cases of neuromotor health issues, due to overall population aging, motivated a growing research interest in improving rehabilitation processes with robotics. The performed studies opened the possibility to include other auxiliary technologies in physical and occupational therapy, like virtual reality and remote interaction between patients and therapists. Although there are verified and potential benefits to rehabilitation provided by these techniques, there are still few attempts towards tooling and methodology standardization, which could lead to faster developments. This work describes the creation of a proposed common computational platform for robotic rehabilitation studies, with support for virtual games and telecommunication. A preceding literature review helped to determine the requirements and development tools for such multipurpose system. Its modular and configurable design aims to allow components reuse and adaptability to different robotic therapy cases, even ones not initially intended, preventing work duplication. Details about the system\'s structure, components and operation are shown, focusing its provided flexibility. Multiplayer games involving position and force control are also created to test the proposed system in real and simulated environment, in order to demonstrate its usability for application and evaluation of robotic rehabilitation strategies. At the end, the results obtained so far are discussed and considerations about missing points and future developments are made.
Nas últimas décadas, o aumento global nos casos de problemas de saúde neuromotores, devido ao envelhecimento da população, motivou um interesse crescente na pesquisa sobre melhoria de processos de rehabilitação utilizando robótica. Os estudos realizados realizados abriram possibilidade de se incluir outras tecnologias auxiliares na terapia física e ocupacional, como realidade virtual e interação remota entre pacientes e terapeutas. Apesar dos benefícios verificados ou potenciais da aplicação dessas técnicas, ainda há poucas iniciativas no sentido de padronizar ferramentas e metodologias para sua implementação e teste, o que poderia catalisar os avanços na área. Esse trabalho descreve a criação de uma plataforma computacional comum para estudos de Reabilitação Robótica, com suporte a utilização de Jogos Sérios e teleoperação. Uma revisão bibliográfica prévia ajudou a definir os requisitos e ferramentas de desenvolvimento adequadas para tal sistema multipropósito. Seu projeto modular e configurável tem o intuito de permitir reutilização de componentes e sua fácil adaptação a diferentes tipos de terapia, mesmo não inicialmente planejadas, evitando duplicação de trabalho. Jogos multijogador envolvendo controle de força e posição são também criados para testar o sistema proposto em situações reais ou simuladas, de modo a demonstrar sua utilidade para aplicação Detalhes de sua estrutura de operação, protocolos de comunicação e componentes são mostrados, destacando-se a flexibilidade oferecida. Testes simples de viabilidade com indivíduos saudáveis são realizados, a fim de demonstrar sua utilidade para aplicação e avaliação de estratégias de reabilitação robótica. Ao fim, os resultados obtidos até então são discutidos, e considerações sobre informações ainda faltantes e trabalhos futuros são feitas.

Smart Environment is built with the help of embedded system that can give an access to the environment in which it is placed. The embedded systems are electronic systems constituting electronic devices which are specially built to facilitate certain processes such as the human interaction with an environment. These systems play a vital role in an electronic application systems such as  medical diagnosis, geological investigation, surveillances, cash records, play stations and etc. The Mobile Adaptable Surveillance System for Critical Areas (MASURCA) is an embedded system wireless sensor network application system that embodies both the hardware (node) and software. In this thesis project, Development of Hardware Platform for Mobile Adaptable Surveillance System for Critical Areas, the design and development of the hardware platform for the system is built. The project deals with building the smart system comprising of radio frequency (RF) radio, global positioning system (GPS) sensor module, Accelerometer, Temperature sensor, and Ultrasonic sensor.  The design focuses on designing the power supply stage from a single AA battery in such a way that the entire connected components and sensors get a required supply source with best possible extended battery life. The design of power supply stage includes EMC, signal integrity, thermal and efficiency design considerations, and prototyping and testing of the power supply stage.  First the sensors and the necessary design components are selected with more emphasis on their power/energy consumption, size of footprint and signal output (I2C-bus protocol interface capability). Then the system schematic will be designed and simulated for signal integrity and design rule using the Mentor Graphics design entry Dxdesigner and hyperlynx Analog simulator. The designed schematic is also packaged and the part is listed and the bill of material is generated so as to be able to annotate to the PCB layout and later component placement.  Likewise, the PCB layout is designed according to the Saab Training Systems AB’s standards, regulatory guidelines and standards, and the MASURCA main node system specific requirements. The project will also design and provide the mechanical enclosure kit and software development kit for the MASURCA main node hardware platform. Finally testing and evaluation of the system is done to make the hardware ready for the application implementation.

Automated visual recognition and detection processes are becoming increasingly prevalent in almost all scientific fields and being currently implemented in many fields of industry. In most cases, systems are painstakingly designed and developed in order to detect only a single and specific object or property of an object. The objective of this project was to create a framework of development in which any object distinguishable in a two-dimensional digital image could be analyzed and subsequently detected in other images. Furthermore, as new methods are developed, they could be easily incorporated into this framework to ultimately improve the performance of the system.
This thesis describes a highly adaptable, general-application visual detection system as well as several innovative methods for the description of objects without which such adaptivity would be impossible. Two-dimensional, still images are analyzed and objects of interest can be introduced to the system. Objects are then described by a variety of properties through derived attributes and stored in a database. Occurrences of these objects can then be detected in future images through comparisons to selected models. The system is fully expandable in that new properties and comparison techniques or criteria can be added as they are developed and as their need becomes apparent. The system is presented with a basic set of attribute representations and methods of comparison, and their development and origin are described in detail. The database structure is outlined and the process by which new properties and comparative methods can be added is described. Seventeen different images containing nearly two thousand separate objects were searched for various model objects and the average classification accuracy was 98.3%. In most images, more than 100 object classifications could be performed per second at an accuracy higher than 95% when no higher order analyses were required.

A novel noise control system is developed using adaptable tuned vibration absorbers (ATVA) to interact with a vibrating host structure in such a way as to reduce radiated acoustic energy. ATVA's are single-degree-of-freedom resonant devices that can change their resonant frequency and damping over a range. This ATVA noise control system is targeted at applications with tonal disturbances such as propeller aircraft. The motivation for this work is to better understand and experimentally demonstrate the noise control performance of globally detuned vibration absorbers (i.e. tuned away from the disturbance) compared to that of perfectly tuned devices on complex structures. A two-tier hierarchical control approach is used where a global control algorithm attempts to minimize a global parameter such as radiated acoustic energy by directing the adaptation of subordinate ATVA's. The global control algorithm uses an adaptive simplex search algorithm that requires no initial knowledge of the structure or the ATVA's. The ATVA's also require no model of the structure, each utilizing only the local vibration of its own mass and control gains set by the global controller. Noise control using a single ATVA is first studied on a small simply supported plate. Then, a multiple ATVA system is tested on a large plate structure at several test frequencies where many structural modes participate. Noise reductions up to 22 dB are achieved at locations in the radiated field. Further, it is found in some cases, classic tuning of the ATVA results in increased structural noise radiation. ATVA's are realized by outfitting typical inertial (proof-mass) actuators with a classical feedback loop. The device's resonant frequency and damping can be controlled independently, yet simultaneously via two control gains. The ATVA's are designed, built, and characterized for their adaptable domain and power requirements. A cohesive analytical model of the ATVA is also developed and used to compliment the experimental results.
Ph. D.