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Application of control theory to the hyperthermia problem.Potocki, Jon Kyle. January 1992 (has links)
The objective of a hyperthermia cancer treatment is to heat the tumor tissue to a therapeutic level while limiting the detrimental effects experienced by the surrounding normal tissue. To achieve an optimal treatment requires knowledge of the resulting temperature response and an understanding of the complex interaction between the thermal response, the applied power, and the blood flow in the target tissue region. This dissertation considers model reduction to overcome the large dimensions associated with thermal modelling, extended Kalman filtering to estimate both the unmeasured temperature states and the unknown blood perfusion magnitudes, optimization of the applied power to achieve the best thermal response, and optimal servomechanism control to attain the desired regulated output tracking. A controller methodology that combines thermal estimation, applied power optimization, and optimal servomechanism control with a simple expert system shell is examined. This controller methodology is analyzed for a simulated scanned focussed ultrasound system (SFUS) based upon the bioheat transfer equation (BHTE) model of the thermal response in the target region. The results of the presented studies illustrate the following important points. First, open-loop reduced-order models based on the balanced transformation provide drastic model reduction for controller design purposes. Second, the success of thermal estimation depends on the number and the location of the thermal sensors, and the accuracy of the modelled blood perfusion profile. Third, multiple modelling in estimation provides an alternate technique for overcoming model mismatch associated with the modelling of the blood perfusion pattern. Fourth, the choice of the set points for the optimal servomechanism controller play a crucial role in the resulting tissue temperatures. Fifth, the scan parameter sets that result in optimal SFUS power profiles need to be changed on-line during a treatment as the blood perfusion magnitude and pattern are estimated. Finally, to fully automate a hyperthermia treatment requires that the expertise of the clinician be incorporated into the controller design. Hierarchical control provides a means of incorporating the expert system shell at the higher levels of the controller, while maintaining optimal servomechanism control at the lower levels.
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Hardware-Software Integrated Silicon Photonic SystemsCalhoun, David Mark January 2017 (has links)
Fabrication of integrated photonic devices and circuits in a CMOS-compatible process or foundry is the essence of the silicon photonic platform. Optical devices in this platform are enabled by the high index contrast between silicon and silicon on insulator. These devices offer potential benefits when integrated with existing and emerging high performance microelectronics. Integration of silicon photonics with small footprints and power-efficient and high-bandwidth operation has long been cited as a solution to existing issues in high performance interconnects for telecommunications and data communication. Stemming from this historic application in communications, new applications in sensing arrays, biochemistry, and even entertainment continue to grow. However, for many technologies to successfully adopt silicon photonics and reap the perceived benefits, the silicon photonic platform must extend toward development of a full ecosystem. Such extension includes implementation of low cost and robust electronic-photonic packaging techniques for all applications. In an ecosystem implemented with services ranging from device fabrication all the way to packaged products, ease-of-use and ease-of-deployment in systems that require many hardware and software components becomes possible.
With the onset of the Internet of Things (IoT), nearly all technologies—sensors, compute, communication devices, etc.—persist in systems with some level of localized or distributed software interaction. These interactions often require a level of networked communications. For silicon photonics to penetrate technologies comprising IoT, it is advantageous to implement such devices in a hardware-software integrated way. Meaning, all functionalities and interactions related to the silicon photonic devices are well defined in terms of the physicality of the hardware. This hardware is then abstracted into various levels of software as needed in the system. The power of hardware-software integration allows many of the piece-wise demonstrated functionalities of silicon photonics to easily translate to commercial implementation.
This work begins by briefly highlighting the challenges and solutions for transforming existing silicon photonic platforms to a full-fledged silicon photonic ecosystem. The highlighted solutions in development consist of tools for fabrication, testing, subsystem packaging, and system validation. Building off the knowledge of a silicon photonic ecosystem in development, this work continues by demonstrating various levels of hardware-software integration. These are primarily focused on silicon photonic interconnects.
The first hardware-software integration-focused portion of this work explores silicon microring-based devices as a key building block for greater silicon photonic subsystems. The microring’s sensitivity to thermal fluctuations is identified not as a flaw, but as a tool for functionalization. A logical control system is implemented to mitigate thermal effects that would normally render a microring resonator inoperable. The mechanism to control the microring is extended and abstracted with software programmability to offer wavelength routing as a network primitive. This functionality, available through hardware-software integration, offers the possibility for ubiquitous deployment of such microring devices in future photonic interconnection networks.
The second hardware-software integration-focused portion of this work explores dynamic silicon photonic switching devices and circuits. Specifically, interactions with and implications of high-speed data propagation and link layer control are demonstrated. The characteristics of photonic link setup include transients due to physical layer optical effects, latencies involved with initializing burst mode links, and optical link quality. The impacts on the functionalities and performance offered by photonic devices are explored. An optical network interface platform is devised using FPGAs to encapsulate hardware and software for controlling these characteristics using custom hardware description language, firmware, and software. A basic version of a silicon photonic network controller using FPGAs is used as a tool to demonstrate a highly scalable switch architecture using microring resonators. This architecture would not be possible without some semblance of this controller, combined with advanced electronic-photonic packaging. A more advanced deployment of the network interface platform is used to demonstrate a method for accelerating photonic links using out-of-band arbitration. A first demonstration of this platform is performed on a silicon photonic microring router network. A second demonstration is used to further explore the feasibility of full hardware-software integrated photonic device actuation, link layer control, and out-of-band arbitration. The demonstration is performed on a complete silicon photonic network with both spatial switching and wavelength routing functionalities.
The aforementioned hardware-software integration mechanisms are rigorously tested for data communications applications. Capabilities are shown for very reliable, low latency, and dynamic high-speed data delivery using silicon photonic devices. Applying these mechanisms to complete electronic-photonic packaged subsystems provides a strong path to commercial manifestations of functional silicon photonic devices.
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Dynamical systems theory and school changeTse, Pak-hoi, Isaac. January 2006 (has links)
Thesis (Ph. D.)--University of Hong Kong, 2007. / Title proper from title frame. Also available in printed format.
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Algebraic methods for the solution of some linear matrix equationsJanuary 1979 (has links)
by T.E. Djaferis and S.K. Mitter. / Bibliography: p. 33. / "February 1979." / Supported by ERDA under Grant ERDA-E(49-18)-2087 NASA Grant NGL-22-009-124 Defense Advanced Research Projects Agency, Office of Naval Research Contract no. N0014-75-C-0661 Work Order 2095
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Customer allocation policies in a two server network: stability and exact asymptoticsCoombs-Reyes, Jerome D. 01 December 2003 (has links)
No description available.
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Toward a systematic theory of symbolic actionMcKercher, Patrick Michael 05 1900 (has links)
Though Kenneth Burke has often been dismissed as a brilliant but idiosyncratic
thinker, this dissertation will argue that he is actually a precocious systems theorist.
The systemic and systematic aspects of Burke’s work will be demonstrated by
comparing it to the General Systems Theory (GST) of biologist Ludwig von
Bertalanffy. Though beginning from very different starting points, Bertalanffy and
Burke develop similar aims, methods, and come to remarkably similar conclusions
about the nature and function of language.
The systemic nature of Burke’s language philosophy will also become evident
through an analysis of the Burkean corpus. Burke’s first book contains several
breakthrough ideas that set him irrevocably upon the path of a systemic theory of
symbolic action. Burke’s next book, influenced by GST-inspired biology, seeks to
understand the nature of associative networks by employing an organic metaphor.
Burke’s interest in systems comes from his desire to repair the cultural system
crumbling around him as a result of the Depression. Consequently his next book,
Attitudes Toward History, studies what happens to such “orientations” (i.e., the
systems by which humans classify and evaluate the world) during epistemological
crises. The Philosophy of Literary Form is concerned primarily with the function of
these orientations.
In A Grammar of Motives Burke seeks to understand the basis for transformation of these evaluative systems, and in A Rhetoric of Motives he demonstrates
how these transformations are used to persuade. Burke next turns his attention to
understanding a small part of the system, a theological doctrine, in The Rhetoric of
Religion.
Burke’s theory appears plausible when compared to and supplemented by GST
and the related self-organizing system theory. Furthermore, a paradigm shift to non-mechanistic
cognitive theory allows us to refine and extend Burke’s intuitive theory of
symbolic action. The final chapter will argue that symbolic action is the manipulation
of the quality space, which is a
multi-dimensional model for the super-system
composed of mental, linguistic and cultural sub-systems. In mental systems, skeletal
information structures called schemas combine to form simple models, which in turn
combine to form a model of the world. Similarly, a culture can be seen as a system
of schemas held in common by the group. The linguistic system labels, transmits and
thus evokes these schemas. The primary means by which the quality space becomes
reconfigured is through metaphor, which creates new schemas, and modifies the
connections between schemas (and thus the position and relative value of a schema).
Metaphor, therefore, is the basis of symbolic action.
This systemic theory of symbolic action may be modeled by Connectionist
networks. These analogical neural networks provide a model for how brains form
and associate categories and support Burke’s assertion that thought is primarily
analogical and categorical, thus affording the means for refining Burke’s theory of
symbolic action. Ultimately, such a theory may provide a unified field theory for
rhetoric, showing how various symbolic action strategies work and interrelate.
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The application of systems thinking as applied to corporate communication.Jordan, Graham. January 2003 (has links)
P & 0 Grindrod Logistics (Pty) Ltd (POGL) was the focus of study over a period of two
years and served as the learning field for the systemic appreciation of complex problem resolution.
Organisational conversation and communication surfaced as an issue within the
organisation during this period of research and served as the system of interest (SOl)
warranting further appreciation and understanding. This paper surfaces an
understanding of the complex and emergent issues and dilemmas of the SOl through a
process of generative learning, using systems thinking and a brief theoretical
understanding of communication, as a multimethodological paradigm. The reflective
approach was to gain knowledge and understanding of the SOl and then to subject the
knowledge claims to validation. Various worldviews emerged, as to the causes and
reasons for non-communication. This required the surfacing of personal issues and
experiences, an understanding of emotions, appreciation for other's points of view,
values, knowledge, perceptions, beliefs and ethics of the staff at POGL. A systemic
appreciation facilitated the emergence and understanding of behaviours of the people,
specifically as regards the leadership style and the knowledge-power position of that
management style. During my research, my observation was that organisational
conversations were limited to these issues, void of any strategic value or vision content.
In most job functions including managerial positions, authority levels, empowerment,
innovation, and creativity, was replaced with a command style leadership. People lived
in fear of reprisal and did as they were told. Retrenchments and restrictions on capital
expenditure, equipment maintenance and general day to day running costs, further
limited team building, personal and organisational learning, by removing responsibility
and authority and relocating this to the Executive Team. The absence of a
communicated vision negatively affected commitment, productivity decreased, and focus
and energy was lost. A culture of non-communication, namely, distrust, emotions,
disrespect, and credibility, emerged as barriers to effective communication and were
noted as concerns of the people.
The proposed intervention is the creation of a learning organisation, with the purposeful
construction of a strategy to enhance and maximise organisational learning. The process
is designed as systems starting with leadership development, progressing through
strategic conversation, a system to improve communication, recognition, reward and
performance management systems and staff and management development. The
overall objective is to improve organisational effectiveness. The intervention has
developed as a generative learning process, ie the reflections of the two-year research
process and the additional reflections and learnings from this paper. This was a
conscious attempt to improve competitiveness, productivity and innovation, to
understand uncertainties and the need for learning in order to improve adaptability and
efficiency during these times of change and uncertainty in POGL. As evidenced from the
literary review of systems thinking and the application to the issues in this organisation,
we are dealing with a complex and dynamic environment. 'Learning enables a quicker
and more effective response to this environment, increases information sharing,
communication, understanding, increases the level of energy and excitement in
individuals and the quality of decisions made in organisations.' (April, 2000:49)
The whole process requires a culture change for the organisation and will take time.
However, I am of the opinion that the inclusion of staff in organisational decision making
complemented with staff development will improve innovation and creativity and promote
a sustainable organisation. People desire to be part of a community, where expansive
thinking is encouraged and recognition and reward part of the process of building trust
and respect; where the people talk to one another, learn from each other in ongoing
dialogue, exchange advice, coach and mentor each other. Success is in teamwork,
personal mastery, a shared vision and developing leaders capable of dealing with the
complexities of the present and the future. The five learning disciplines, namely, systems
thinking, personal mastery, team building , mental models and shared vision are seen in
this paper as a foundation and enhance aspiration, reflective conversation and
understanding complexity. (April , 2000:52) Jack Welch, formerly of General Electric,
quoted in April (2000:50) said of learning: 'Our behaviour is driven by a fundamental core
belief: The desire and the ability of an organisation to continually learn from any source -
and to rapidly convert this learning into action - is its ultimate competitive advantage.' / Thesis (M.B.A.)-University of Natal, Durban, 2003.
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Egzistencinis socialinio darbo modelis šiuolaikinio socialinio darbo modelių kontekste / Existential social work model in the context of contemporary social work modelsBogdanova, Natalja 23 June 2014 (has links)
Egzistencinis socialinio darbo modelis yra svarbus, įtakingas ir reikšmingas šiuolaikiniam socialiniam darbui. Kai kurių teoretikų nuomone, jis iki šiol nėra deramai išvystytas ir pritaikytas praktikai, nežiūrint to, kad jo principai ir teiginiai yra aktualūs socialiniame darbe. Dėl šio fakto yra būtina tirti egzistencinio modelio privalumus praktinėje profesinėje veikloje, jo integracijos su kitais modeliais galimybes, taip pat nustatyti jo taikymo trūkumus ir apribojimus. Tyrimo tikslas – išsiaiškinti ir įvertinti egzistencinio modelio taikymo perspektyvą šiuolaikinių socialinio darbo modelių kontekste. Tyrimo metodu buvo pasirinktas kokybinis lyginamosios turinio analizės metodas. Egzistencinis modelis buvo lyginamas su bihevioristiniu ir sistemų teorijos socialinio darbo modeliais pagal išskirtas kategorijas. Tyrimo rezultatai parodė, kad egzistencinis modelis išsiskiria savo filosofiniu pagrindu, kuris nulemia šiuos nepanašumus ir netgi prieštaravimus su kitais dviem modeliais: žmogaus sampratą, kliento bruožai, esminės problemų priežastys, intervencijos tikslas, pokyčio kliento gyvenime traktavimas. Įvertinus egzistencinio modelio integravimo su kitais dviem modeliais galimybes, išaiškėjo, kad integravęs į savo teorinę bei praktinę konstrukciją sistemų teorijos probleminės situacijos įvykių analizės ir bihevioristinio modelio intervencijos metodus bei technikas, egzistencinis modelis tik laimėtų, praturtintų ir praplėstų savo teorinę ir praktinę dalis. Buvo nustatyti... [toliau žr. visą tekstą] / Existential model of social work is important, weighty and significant for contemporary social work. Though some theorists point out that in spite of the relevance of the existential model it is not developed well and not fit to social work practice. Therefore it is necessary to search and analyse the advantages of the model and potentiality of integration with another models of social work as well as to identify the weaknesses. The aim of the research is to evaluate the perspective of the existential model in the context of contemporary models of social work. The method of the research is qualitative comparative content analysis. The existential model is to be compared with behavioural and system theory models according to the given categories. The results of the research show that the most obvious different between observed models is the philosophical background of the existential model. This background set even inconsistency in definition of such categories as conception of human, description of client, main aim of intervention and interpretation of changes in client’s situation. When a possibility of integration of existential and other two models was evaluated, it came clear, that existential model can benefit much for its theoretical frame and practice of including of the system theory’s point of analysis of problems as well as some behavioural intervention methods and techniques. There were find following advantages of the existential model: 1) explanation of... [to full text]
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Logical soft systems for modeling industrial machinery buying decisions in Thailand /Nakswasdi, Suravut. Unknown Date (has links)
Action research methods using Soft Systems Methodology (SSM) and Logico-Linguistic Modelling (LLM) were used to investigate and model decisions made in the buying of industrial machinery by twelve companies in Thailand. The research was exploratory and attempted to discover if SSM and LLM models could be used to structure problems that were common to more than one organization. The research also sought to discover if SSM could be used to build models in the Thai language and in a Thai cultural environment. The experiment can be considered a success in so far as the participants found the results both interesting and informative. Also the research produced a considerable amount of new information that can be used in the marketing of industrial machinery. However, neither the SSM models nor the LLM models could be used in the way their authors had intended. The logical and epistemological status of the models could not be explained in the available contact time. As a result the researcher developed a simplified modelling method. The theoretical conclusion is that a simplified version of SSM/LLM needs to be developed to structure problems that transcend organization boundaries. / Thesis (DBA(DoctorateofBusinessAdministration))--University of South Australia, 2006.
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Complex systems as lenses on learning and teachingHurford, Andrew Charles. January 1900 (has links)
Thesis (Ph. D.)--University of Texas at Austin, 2007. / Vita. Includes bibliographical references.
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