Engineering designers commonly make sequential information acquisition decisions such as selecting designs for performance evaluation, selecting information sources, deciding whom to communicate with in design teams, and deciding when to stop design exploration. There is significant literature on normative decision making for engineering design, however, there is a lack of descriptive modeling of how designers actually make information acquisition decisions. Such descriptive modeling is important for accurately modeling design decisions, identifying sources of inefficiencies, and improving the design process. To that end, the research objective of the dissertation is to understand how designers make sequential information acquisition decisions and identify models that provide the best description of a designer’s decisions strategies. For gaining this understanding, the research approach consists of a synthesis of descriptive theories from psychological and cognitive sciences, along with empirical evidence from behavioral experiments under different design situations. Statistical Bayesian inference is used to determine how well alternate descriptive decision models describe the experimental data. This approach quantifies a designer's decision strategies through posterior parameter estimation and Bayesian model comparison. <br><br>Two research studies, presented in this dissertation, focus on assessing the effects of monetary incentives, fixed budget, type of design space exploration, and the availability of system-wide information on information acquisition decisions. The first study presented in this dissertation investigates information acquisition by an individual designer when multiple information sources are available and the total budget is limited. The results suggest that the student subjects' decisions are better represented by the heuristic-based models than the expected utility(EU)-based models. <br>While the EU-based models result in better net payoff, the heuristic models used by the subjects generate better design performance. The results also indicate the potential for nudging designers' decisions towards maximizing the net payoff by setting the fixed budget at low values and providing monetary incentives proportional to the saved budget.<br><br>The second study investigates information acquisition through communication. The focus is on designers’ decisions about whom to communicate with, and how much to communicate when there is interdependence between subsystems being designed. This study analyzes team communication of NASA engineers at a mission design laboratory (MDL) as well as of engineering students designing a simplified automotive engine in an undergraduate classroom environment. The results indicate that the rate of interactions increases in response to the reduce in system-level design performance in both settings. Additionally, the following factors seem to positively influence communication decisions: the pairwise design interdependence, node-wise popularity (significant with NASA MDL engineers due to large team size), and pairwise reciprocity.<br><br>The dissertation work increases the knowledge about engineering design decision making in following aspects. First, individuals make information acquisition decisions using simple heuristics based on in-situ information such as available budget amount and present system performance.<br>The proposed multi-discipline approach proves helpful for describing heuristics analytically and inferring context-specific decision strategies using statistical Bayesian inference. This work has potential application in developing decision support tools for engineering design. Second, the comparison of communication patterns between student design teams and NASA MDL teams reveals that the engine experiment preserves some but not all of the communication patterns of interest. We find that the representativeness depends not on matching subjects, tasks, and context separately, but rather on the behavior that results from the interactions of these three dimensions. This work provides lessons for designing representative experiments in the future.

Typescript (photocopy). / Digitized by Kansas State University Libraries / Department: Electrical and Computer Engineering.

Thesis (PhD (Logistics))--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: The design of a water distribution system (WDS) involves finding an acceptable trade-off between cost minimisation and the maximisation of numerous system benefits, such as hydraulic reliability and surplus capacity. The primary design problem involves cost-effective specifica- tion of a pipe network layout and pipe sizes (which are typically available in a discrete set of commercial diameters) in order to satisfy expected consumer water demands within required pressure limits. The problem may be extended to consider the design of additional WDS com- ponents, such as reservoirs, tanks, pumps and valves. Practical designs must also cater for the uncertainty of demand, the requirement of surplus capacity for future growth, and the hydraulic reliability of the system under different demand and potential failure conditions. A detailed literature review of exact and approximate approaches towards single-objective (minimum cost) WDS design optimisation is provided. Essential topics which have to be included in any modern WDS design paradigm (such as demand estimation, reliability quantification, tank design and pipe layout) are discussed. A number of formative concepts in multi-objective evo- lutionary optimisation are also reviewed (including a generic problem formulation, performance evaluation measures, comparative testing strategies, and suitable classes of metaheuristics). The two central themes of this dissertation are conducting multi-objective WDS design optimi- sation using metaheuristics, and a critical examination of surrogate measures used to quantify WDS reliability. The aim in the first theme is to compare numerous modern metaheuristics, in- cluding several multi-objective evolutionary algorithms, an estimation of distribution algorithm and a recent hyperheuristic named AMALGAM (an evolutionary framework for the simulta- neous incorporation of multiple metaheuristics applied here for the first time to a real-world problem), in order to determine which approach is most capable with respect to WDS design optimisation. Several novel metaheuristics are developed, as well as a number of new variants of existing algorithms, so that a total of twenty-three algorithms were compared. Testing with respect to eight small-to-large-sized WDS benchmarks from the literature reveals that the four top-performing algorithms are mutually non-dominated with respect to the vari- ous performance metrics. These algorithms are NSGA-II, TAMALGAMJndu, TAMALGAMndu and AMALGAMSndp (the last three being novel variants of AMALGAM). However, when these four algorithms are applied to the design of a very large real-world benchmark, the AMALGAM paradigm outperforms NSGA-II convincingly, with AMALGAMSndp exhibiting the best perfor- mance overall. As part of this study, a novel multi-objective greedy algorithm is developed by combining several heuristic design methods from the literature in order to mimic the design strategy of a human engineer. This algorithm functions as a powerful local search. However, it is shown that such an algorithm cannot compete with modern metaheuristics, which employ advanced strategies in order to uncover better solutions with less computational effort. The second central theme involves the comparison of several popular WDS reliability surro- gate measures (namely the Resilience Index, Network Resilience, Flow Entropy, and a novel mixed surrogate measure) in terms of their ability to produce designs that are robust against pipe failure and water demand variation. This is the first systematic study on a number of WDS benchmarks in which regression analysis is used to compare reliability surrogate measures with probabilistic reliability typically derived via simulation, and failure reliability calculated by considering all single-pipe failure events, with both reliability types quantified by means of average demand satisfaction. Although no single measure consistently outperforms the others, it is shown that using the Resilience Index and Network Resilience yields designs that achieve a better positive correlation with both probabilistic and failure reliability, and while the Mixed Surrogate measure shows some promise, using Flow Entropy on its own as a quantifier of re- liability should be avoided. Network Resilience is identified as being a superior predictor of failure reliability, and also having the desirable property of supplying designs with fewer and less severe size discontinuities between adjacent pipes. For this reason, it is recommended as the surrogate measure of choice for practical application towards design in the WDS industry. AMALGAMSndp is also applied to the design of a real South African WDS design case study in Gauteng Province, achieving savings of millions of Rands as well as significant reliability improvements on a preliminary engineered design by a consulting engineering firm. / AFRIKAANSE OPSOMMING: Die ontwerp van waterverspreidingsnetwerke (WVNe) behels die soeke na ’n aanvaarbare afruiling tussen koste-minimering en die maksimering van ’n aantal netwerkvoordele, soos hidroliese betroubaarheid en surpluskapasiteit. Die primere ontwerpsprobleem behels ’n koste-doeltreffende spesifikasie van ’n netwerkuitleg en pypgroottes (wat tipies in ’n diskrete aantal kommersiele deursnedes beskikbaar is) wat aan gebruikersaanvraag binne sekere drukspesifikasies voldoen. Die probleem kan uitgebrei word om die ontwerp van verdere WVN-komponente, soos op- gaardamme, opgaartenks, pompe en kleppe in ag te neem. Praktiese WVN-ontwerpe moet ook voorsiening maak vir onsekerheid van aanvraag, genoegsame surpluskapsiteit vir toekom- stige netwerkuitbreidings en die hidroliese betroubaarheid van die netwerk onder verskillende aanvraag- en potensiele falingsvoorwaardes. ’n Omvattende literatuurstudie word oor eksakte en benaderde oplossingsbenaderings tot enkel- doelwit (minimum koste) WVN-ontwerpsoptimering gedoen. Sentrale temas wat by heden- daagse WVN-ontwerpsparadigmas ingesluit behoort te word (soos aanvraagvooruitskatting, die kwantifisering van betroubaarheid, tenkontwerp en netwerkuitleg), word uitgelig. ’n Aantal basiese konsepte in meerdoelige evolusionˆere optimering (soos ’n generiese probleemformulering, werkverrigtingsmaatstawwe, vergelykende toetsingstrategie¨e, en sinvolle klasse metaheuristieke vir WVN-ontwerp) word ook aangeraak. Die twee sentrale temas in hierdie proefskrif is meerdoelige WVN-ontwerpsoptimering deur mid- del van metaheuristieke, en ’n kritiese evaluering van verskeie surrogaatmaatstawwe vir die kwantifisering van netwerkbetroubaarheid. Die doel in die eerste tema is om ’n aantal moderne metaheuristieke, insluitend verskeie meerdoelige evolusionere algoritmes en die onlangse hiper- heuristiek AMALGAM (’n evolusionere raamwerk vir die gelyktydige insluiting van ’n aantal metaheuristieke wat hier vir die eerste keer op ’n praktiese probleem toegepas word), met mekaar te vergelyk om sodoende ’n ideale benadering tot WVN-ontwerpoptimering te identi- fiseer. Verskeie nuwe metaheuristieke sowel as ’n aantal nuwe variasies op bestaande algoritmes word ontwikkel, sodat drie en twintig algoritmes in totaal met mekaar vergelyk word. Toetse aan die hand van agt klein- tot mediumgrootteWVN-toetsprobleme uit die literatuur dui daarop dat die vier top algoritmes mekaar onderling ten opsigte van verskeie werkverrigtings- maatstawwe domineer. Hierdie algoritmes is NSGA-II, TAMALGAMJndu, TAMALGAMndu en AMALGAMSndp, waarvan laasgenoemde drie nuwe variasies op AMALGAM is. Wanneer hierdie vier algoritmes egter vir die ontwerp van ’n groot WVN-toetsprobleem ingespan word, oortref die AMALGAM-paradigma die NSGA-II oortui-gend, en lewer AMALGAMSndp die beste resultate. As deel van hierdie studie is ’n nuwe meerdoelige gulsige algoritme ontwerp wat verskeie heuristiese ontwerpsmetodologiee uit die literatuur kombineer om sodoende die on- twerpstrategie van ’n ingenieur na te boots. Hierdie algoritme funksioneer as ’n kragtige lokale soekprosedure, maar daar word aangetoon dat die algoritme nie met moderne metaheuristieke, wat gevorderde soekstrategie¨e inspan om beter oplossings met minder berekeningsmoeite daar te stel, kan meeding nie. Die tweede sentrale tema behels die vergelyking van ’n aantal gewilde surrogaatmaatstawwe vir die kwantifisering van WVN-betroubaarheid (naamlik die elastisiteitsindeks, netwerkelastisiteit, vloei-entropie en ’n gemengde surrogaatmaatstaf ) in terme van die mate waartoe hul gebruik kan word om WVNe te identifiseer wat robuust is ten opsigte van pypfaling en variasie in aanvraag. Hierdie proefskrif bevat die eerste sistematiese vergelyking deur middel van regressie-analise van ’n aantal surrogaatmaatstawwe vir die kwantifisering van WVN-betroubaarheid en stogastiese betroubaarheid (wat tipies via simulasie bepaal word) in terme van ’n aantal toetsprobleme in die literatuur. Alhoewel geen enkele maatstaf as die beste na vore tree nie, word daar getoon dat gebruik van die elastisiteitsindeks en netwerkelastisiteit lei na WNV-ontwerpe met ’n groter positiewe korrelasie ten opsigte van beide stogastiese betroubaarheid en falingsbetroubaarheid. Verder toon die gebruik van die gemengde surrogaatmaatstaf potensiaal, maar die gebruik van vloei-entropie op sy eie as kwantifiseerder van betroubaarheid behoort vermy te word. Netwerkelastisiteit word as ’n hoe-gehalte indikator van falingsbetroubaarheid geidentifiseer en het ook die eienskap dat dit daartoe instaat is om ontwerpe met ’n kleiner aantal diskontinuiteite sowel as van ’n minder ekstreme graad van diskontinuiteite tussen deursnedes van aangrensende pype daar te stel. Om hierdie rede word netwerkelastisiteit as die surogaatmaatstaf van voorkeur aanbeveel vir toepassings van WVN-ontwerpe in die praktyk. AMALGAM word ook ten opsigte van ’n werklike Suid-Afrikaanse WVN-ontwerp gevallestudie in Gauteng toegepas. Hierdie toepassing lei na die besparing van miljoene rande asook noe- menswaardige verbeterings in terme van netwerkbetroubaarheid in vergeleke met ’n aanvanklike ingenieursontwerp deur ’n konsultasiefirma.

D.Ed. / In South Africa the water and sanitation sector faces many problems in the delivery of services to ensure that all South Africans have access to safe and sufficient water resources and adequate sanitation to meet their needs. Local government, mandated to supply these services, has a lack of resources including trained human resources. Distance education learning programmes could be one way of addressing the lack of trained human resources. Distance education can reach a much wider spectrum of people, the costs to the employers can be greatly reduced, less work hours are lost, people, especially women, have the opportunity to study whilst still taking the caring role at home, and learners are also able to learn at their own pace and time. To address the problem it was identified that a framework for the development of outcomes-based distance education learning programmes for adult learners would be beneficial to the programme planners and educators who plan and design distance education learning programmes. The framework was developed based on the research literature explored. A literature study of three issues namely: outcomes-based education, facilitation of adult learning and distance education was undertaken. Theoretical underpinnings were extrapolated from the literature study which were used as the building blocks for the framework. To establish the theoretical underpinnings for the framework the evolution of competency-based education to outcomes-based education was investigated. It was concluded that competency-based education included core elements such as learning that is not time bound, learning that is stated as outcomes, various means can be used to achieve the outcomes, and assessment is based on the stated outcomes. These concepts have become the focus areas in all developments in competency-based as well as outcomes-based education. In the 1990s the education and training sector in South Africa was transformed, and an outcomes-based education system was adopted. A National Qualifications Framework has been introduced which offers a set of principles and guidelines for the education and training sector. These principles and guidelines were examined. Another issue that was scrutinised was the design of outcomes-based training material for the South African situation. Theoretical underpinnings for the framework were extrapolated from the findings of the literature study on the facilitation of adult learning and planning of adult learning programmes. The characteristics of the adult learner and the importance of these characteristics when planning a learning programme for the adult learner were examined. Two learning theories namely constructivism and transformative learning provided valuable insights into how adults learn in the learning situation. How to plan a learning programme for adult learners using the Critical Events Model, was explained. For the extrapolation of the theoretical underpinnings for the framework from distance education the evolution of distance education, from an informal style of correspondence education to a more formal style of single media correspondence education and eventually to a formal distance education system using multi-media methods was also explored. All these theoretical underpinnings were consolidated into the final product of this study namely a framework for the development of outcomes-based distance education learning programmes for the adult learners in the water and sanitation sector. The framework is designed as an independent document to be used by the programme planners and educators of distance education learning programmes. Within the framework the theoretical underpinnings are applied, guidance and advice on how to plan and design events in the distance learning programmes is given, and an example of how to design outcomes-based training material is included. Checklists are included at the end of every event in the framework. Programme planners and educators can use the checklist to determine if all the activities in the event have been completed. This makes the framework a guide that can be used by the most inexperienced programme planners and educators. It is hoped that this framework will guide many programme planners and educators as they are faced with the immense task of assisting in meeting the challenges of education and training in the water and sanitation sector in South Africa.

Acoustic networks of autonomous underwater vehicles (AUVs) show great promise, but a lack of simulation tools and reliance on protocols originally developed for terrestrial radio networks has hindered progress. This work addresses both issues. A new simulator of underwater communication among AUVs provides accurate communication modeling and flexible vehicle behavior, while a new routing protocol, location-aware source routing (LASR) provides superior network performance. The new simulator was used to evaluate communication without networking, and then with networking using the coding or dynamic source routing (DSR) protocols. The results confirmed that a network was essential to ensure effective fleet-wide communication. The flooding protocol provided extremely reliable communication but with low message volumes. The DSR protocol, a popular routing protocol due to its effectiveness in terrestrial radio networks, proved to be a bad choice in an acoustic environment: in most cases, it suffered from both poor reliability and low message volumes. Due to the high acoustic latency, even moderate vehicle speeds caused the network topology to change faster than DSR could adapt. DSR's reliance on shortest-path routing also proved to be a significant disadvantage. Several DSR optimizations were also tested; most proved to be unhelpful or actually harmful in an underwater acoustic network. LASR was developed to address the problems noted in flooding and DSR. LASR was loosely derived from DSR, most significantly retaining source routes and the reply/request route discovery technique. However, LASR added features which proved, in simulation, to be significant advantages -- two of the most effective were a link/route metric and a node tracking system. To replace shortest-path routing, LASR used the expected transmission count (ETX) metric. / This allowed LASR to make more informed routing decisions which greatly increased performance compared to DSR. The node tracking system was the most novel addition: using only implicit communication coupled with the use of time-division multiple access (TDMA), the tracking system provided predicted node locations. These predictions made it possible for LASR to proactively respond to topology changes. In most cases, LASR outperformed flooding and DSR in message delivery reliability and message delivery volume. / by Edward A. Carlson. / Thesis (Ph.D.)--Florida Atlantic University, 2009. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2009. Mode of access: World Wide Web.

Controlling the cooperative behaviors of a fleet of autonomous underwater vehicles in a stochastic, complex environment is a formidable challenge in artificial intelligence. The complexity arises from the challenges of limited navigation and communication capabilities of underwater environment. A time critical cooperative operation by acoustic networks of Multiple Cooperative Vehicles (MCVs) necessitates a robust task allocation mechanism and an efficient path planning model. In this work, we present solutions to investigate two aspects of the cooperative schema for multiple underwater vehicles under realistic underwater acoustic communications: a Location-aided Task Allocation Framework (LAAF) algorithm for multi-target task assignment and a mathematical programming model, the Grid-based Multi-Objective Optimal Programming (GMOOP), for finding an optimal vehicle command decision given a set of objectives and constraints. We demonstrate that, the location-aided auction strategies perform significantly better than the generic auction algorithm in terms of effective task allocation time and information bandwidth requirements. In a typical task assignment scenario, the time needed in the LAAF algorithm is only a fraction compared to the generic auction algorithm. On the other hand; the GMOOP path planning technique provides a unique means for multi-objective tasks by cooperative agents with limited communication capabilities. Under different environmental settings, the GMOOP path planning technique is proved to provide a method with balance of sufficient expressive power and flexibility, and its solution algorithms tractable in terms of mission completion time, with a limited increase of overhead in acoustic communication. Prior to this work, existing multi-objective action selection methods were limited to robust networks where constant communication available. / The dynamic task allocation, together with the GMOOP path planning controller, provides a comprehensive solution to the search-classify tasks for cooperative AUVs. / by Yueyue Deng. / Thesis (Ph.D.)--Florida Atlantic University, 2010. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2010. Mode of access: World Wide Web.

A long tradition of progressive pedagogy, running from Jean-Jacques Rousseau and through the work of John Dewey, argues that it is ethically and politically important for students to learn to co-direct the process of inquiry. In a series of recent articles, a group of cognitive scientists (hereafter called ‘DI theorists’) has argued that due to the nature of human cognitive architecture, student-led instructional designs are likely to be less effective than fully teacher-led instructional designs and to exacerbate achievement gaps. Were DI theorists correct, contrary to the intentions of many educators, a great deal of progressive pedagogy would be likely to have negative effects on educational justice. In this dissertation, I argue that the framing of the debate in cognitive science misconstrues the ethical and political value of treating students as cooperative designers of educative experiences. To defend this controversial claim, I advance a Deweyan approach to ethics and justice in instructional design against two recent philosophical challenges. The first challenge, which I call ‘Dewey’s grounding problem’, asserts that Dewey’s appeal to the single ethical and political value of learning is unjustified against dissent and oppressive of reasonable pluralism. The second challenge, which I call ‘Dewey’s problem of elitism’, argues that his call to promote the common good of learning in ethics and politics will sometimes permit or require elitism, aristocracy, or tyranny. Based on the Deweyan ethos I defend, I trace four principles of just instructional design to reassess the claims of DI theorists. I argue that integrating DI theorists’ insights about efficacy and equality as means to create a student co-led community of inquiry confirms many educators’ intuitions: that student-led designs are important parts of developing the skills of inquiry, are well placed as culminating tasks, and are best phased in on a developmental pathway towards greater student independence.

With a focus on dynamics and control, an aquatic quadcopter with optical wireless communications is modeled, designed, constructed, and tested. Optical transmitter and receiver circuitry is designed and discussed. By utilization of the small angle assumption, the nonlinear dynamics of quadcopter movement are linearized around an equilibrium state of zero motion. The set of equations are then tentatively employed beyond limit of the small angle assumption, as this work represents an initial explorative study. Specific constraints are enforced on the thrust output of all four rotors to reduce the multiple-input multiple-output quadcopter dynamics to a set of single-input single-output systems. Root locus and step response plots are used to analyze the roll and pitch rotations of the quadcopter. Ultimately a proportional integral derivative based control system is designed to control the pitch and roll. The vehicle’s yaw rate is similarly studied to develop a proportional controller. The prototype is then implemented via an I2C network of Arduino microcontrollers and supporting hardware. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2016. / FAU Electronic Theses and Dissertations Collection

Ping-Ki Tsang. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references (leaves 87-95). / Abstracts in English and Chinese. / Abstract --- p.i / Acknowledgments --- p.iii / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Motivation and Aims --- p.1 / Chapter 1.2 --- Contributions --- p.3 / Chapter 1.3 --- Overview of the Thesis --- p.4 / Chapter 2 --- Asynchronous Logic g --- p.6 / Chapter 2.1 --- Motivation --- p.6 / Chapter 2.2 --- Timing Models --- p.9 / Chapter 2.2.1 --- Fundamental-Mode Model --- p.9 / Chapter 2.2.2 --- Delay-Insensitive Model --- p.10 / Chapter 2.2.3 --- QDI and Speed-Independent Models --- p.11 / Chapter 2.3 --- Asynchronous Signalling Protocols --- p.12 / Chapter 2.3.1 --- 2-phase Handshaking Protocol --- p.12 / Chapter 2.3.2 --- 4-phase Handshaking Protocol --- p.13 / Chapter 2.4 --- Data Representations --- p.14 / Chapter 2.4.1 --- Dual Rail Coded Data --- p.15 / Chapter 2.4.2 --- Bundled Data --- p.15 / Chapter 2.5 --- Previous Asynchronous Processors --- p.16 / Chapter 2.6 --- Summary --- p.20 / Chapter 3 --- The MSL16 Architecture --- p.21 / Chapter 3.1 --- RISC Machines --- p.21 / Chapter 3.2 --- Stack Machines --- p.23 / Chapter 3.3 --- Forth and its Applications --- p.24 / Chapter 3.4 --- MSL16 --- p.26 / Chapter 3.4.1 --- Architecture --- p.28 / Chapter 3.4.2 --- Instruction Set --- p.30 / Chapter 3.4.3 --- The Datapath --- p.32 / Chapter 3.4.4 --- Interrupts and Exceptions --- p.33 / Chapter 3.4.5 --- Implementing Forth primitives --- p.34 / Chapter 3.4.6 --- Code Density Estimation --- p.34 / Chapter 3.5 --- Summary --- p.35 / Chapter 4 --- Design Methodology --- p.37 / Chapter 4.1 --- Basic Notation --- p.38 / Chapter 4.2 --- Specification of MSL16A --- p.39 / Chapter 4.3 --- Decomposition into Concurrent Processes --- p.41 / Chapter 4.4 --- Separation of Control and Datapath --- p.45 / Chapter 4.5 --- Handshaking Expansion --- p.45 / Chapter 4.5.1 --- 4-Phase Handshaking Protocol --- p.46 / Chapter 4.6 --- Production-rule Expansion --- p.47 / Chapter 4.7 --- Summary --- p.48 / Chapter 5 --- Implementation --- p.49 / Chapter 5.1 --- C-element --- p.49 / Chapter 5.2 --- Mutual Exclusion Elements --- p.51 / Chapter 5.3 --- Caltech Asynchronous Synthesis Tools --- p.53 / Chapter 5.4 --- Stack Design --- p.54 / Chapter 5.4.1 --- Eager Stack Control --- p.55 / Chapter 5.4.2 --- Lazy Stack Control --- p.56 / Chapter 5.4.3 --- Eager/Lazy Stack Datapath --- p.53 / Chapter 5.4.4 --- Pointer Stack Control --- p.61 / Chapter 5.4.5 --- Pointer Stack Datapath --- p.62 / Chapter 5.5 --- ALU Design --- p.62 / Chapter 5.5.1 --- The Addition Operation --- p.63 / Chapter 5.5.2 --- Zero-Checker --- p.64 / Chapter 5.6 --- Memory Interface and Tri-state Buffers --- p.64 / Chapter 5.7 --- MSL16A --- p.65 / Chapter 5.8 --- Summary --- p.66 / Chapter 6 --- Results --- p.67 / Chapter 6.1 --- FPGA based implementation of MSL16 --- p.67 / Chapter 6.2 --- MSL16A --- p.69 / Chapter 6.2.1 --- A Comparison of 3 Stack Designs --- p.69 / Chapter 6.2.2 --- Evaluation of the ALU --- p.73 / Chapter 6.2.3 --- Evaluation of MSL16A --- p.74 / Chapter 6.3 --- Summary --- p.81 / Chapter 7 --- Conclusions --- p.83 / Chapter 7.1 --- Future Work --- p.85 / Bibliography --- p.87 / Publications --- p.95

We present a body of work aimed at understanding and improving the security posture of embedded devices. We present results from several large-scale studies that measured the quantity and distribution of exploitable vulnerabilities within embedded devices in the world. We propose two host-based software defense techniques, Symbiote and Autotomic Binary Structure Randomization, that can be practically deployed to a wide spectrum of embedded devices in use today. These defenses are designed to overcome major challenges of securing legacy embedded devices. To be specific, our proposed algorithms are software- based solutions that operate at the firmware binary level. They do not require source-code, are agnostic to the operating-system environment of the devices they protect, and can work on all major ISAs like MIPS, ARM, PowerPC and X86. More importantly, our proposed defenses are capable of augmenting the functionality of embedded devices with a plethora of host-based defenses like dynamic firmware integrity attestation, binary structure randomization of code and data, and anomaly-based malcode detection. Furthermore, we demonstrate the safety and efficacy of the proposed defenses by applying them to a wide range of real- time embedded devices like enterprise networking equipment, telecommunication appliances and other commercial devices like network-based printers and IP phones. Lastly, we present a survey of promising directions for future research in the area of embedded security.