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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
451

Translating Early Outgrowth Cell Therapy into a Clinically Relevant Approach for Long Term Renoprotection

Kepecs, David 29 November 2013 (has links)
Current therapy for chronic kidney disease (CKD) is limited; however, recent studies have shown that a subpopulation of cells derived from the bone marrow, known as early outgrowth cells (EOCs), are able to attenuate kidney injury. Here we examined the efficacy of a modular tissue engineering system whereby the EOCs might be easily removed in the event of malignant change. While modular therapy mimicked the effects seen with standard EOC therapy, the modules degraded allowing the encapsulated EOCs to enter systemic circulation. Given the presumed egress of EOCs, we explored an alternative strategy for kidney protection. Here we investigated the long-term effectiveness of administering the conditioned medium (EOC-CM) that contains the factors the EOCs secrete, rather than the cells themselves. In these studies, repeated administration of EOC-CM attenuated the structural and functional manifestations of kidney injury suggesting that this approach may provide an effective and feasible, cell-free approach for CKD.
452

Translating Early Outgrowth Cell Therapy into a Clinically Relevant Approach for Long Term Renoprotection

Kepecs, David 29 November 2013 (has links)
Current therapy for chronic kidney disease (CKD) is limited; however, recent studies have shown that a subpopulation of cells derived from the bone marrow, known as early outgrowth cells (EOCs), are able to attenuate kidney injury. Here we examined the efficacy of a modular tissue engineering system whereby the EOCs might be easily removed in the event of malignant change. While modular therapy mimicked the effects seen with standard EOC therapy, the modules degraded allowing the encapsulated EOCs to enter systemic circulation. Given the presumed egress of EOCs, we explored an alternative strategy for kidney protection. Here we investigated the long-term effectiveness of administering the conditioned medium (EOC-CM) that contains the factors the EOCs secrete, rather than the cells themselves. In these studies, repeated administration of EOC-CM attenuated the structural and functional manifestations of kidney injury suggesting that this approach may provide an effective and feasible, cell-free approach for CKD.
453

A choice model for mass customisation of lower-cost and higher-performance housing in sustainable development /

Noguchi, Masayoshi January 2004 (has links)
Market demand for housing changes over time, in response to the wants and needs of both individuals and society. Changes in socio-demographics highlight the emergence of non-traditional households in Canada and influence the configuration of a house (or product) which meets buyers' individual requirements. In turn, this affects the design approach (or process). At the same time, society today requires sustainability in housing development, since building a house consumes large amounts of energy during construction and after occupancy. / Technology that improves the cost and performance of housing has advanced over time. Although some innovative design and construction systems (or approaches) that attempt to meet societal and individual demands for housing are available in today's market, homebuilders tend not to apply unfamiliar approaches to their housing developments, since their business operation is often based on convention. Another reason, which inhibits a builder's adoption of new housing technology, is the extra cost required for seeking and analysing information. Thus, the homebuilders' decision-making processes for the adoption of 'familiar' and 'unfamiliar' design and construction systems (or housing systems) which affect the configuration of housing need to be well programmed. / Accordingly, this study, composed of four parts, focuses initially on identifying housing market trends and issues in Quebec, as well as introducing the new concept of mass customisation that encourages homebuilders to standardise parts of a house---i.e. the creation of mass custom homes. Then, in consideration of this new concept, as well as a value analysis approach that helps facilitate homebuilders' buying decisions, it proposes a choice model for the design and construction approaches to the delivery of 'lower-cost and higher-performance' housing. Thirdly, to assess its practicality, the proposed decision-making model is demonstrated in collaboration with a selected homebuilder in Quebec. Finally, the results of this study are discussed in depth in order to identify future research opportunities. / In view of the demonstration project conducted in this study, the author concluded that the proposed 'choice model' could function effectively as a practical decision-making support tool (or system) that helps open the door for homebuilders to generate and select alternatives that aid them to produce lower-cost and higher-performance housing. As a consequence of programming the homebuilders' buying decision-making process, the goal identification uncertainty and goal/purchase matching uncertainty, which often hinder their adoption of unfamiliar, innovative housing systems, could be reduced, or eliminated.
454

Control system architectures for distributed manipulators and modular robots

Thatcher, Terence W. January 1987 (has links)
This thesis outlines the evolution of computer hardware and software architectures which are suitable for the programming and control of modular robots and distributed manipulators. Fundamental aspects of automating manufacturing functions are considered and the use of flexible machines, constructed from components of a family of mechanical modules and associated control system elements, are proposed. Many of the features of these flexible machines can be identified with those of conventional industrial robots. However a broader class of manufacturing machine is represented in as much as the industrial user defines the kinematics and dynamics of the manipulator. Such flexible machines can be referred to as "modular robots" or, where the mechanical modules are arranged in concurrently operating but mechanically decoupled groups, as "distributed manipulators". The main body of the work reported centred on the design of a family of computer control system elements which can serve a range of distributed manipulator and modular robot forms. These control system elements, whose cost is commensurate with the size and complexity of the manipulator's mechanical configuration, necessarily have many of the features found in robot controllers but also require properties of reconfigurability, programmability, and control system performance for the considerable array of manipulator configurations which can be constructed.
455

Module property verification : A method to plan and perform quality verifications in modular architectures

Kenger, Patrik January 2006 (has links)
Modular product architectures have generated numerous benefits for companies in terms of cost, lead-time and quality. The defined interfaces and the module’s properties decrease the effort to develop new product variants, and provide an opportunity to perform parallel tasks in design, manufacturing and assembly. The background of this thesis is that companies perform verifications (tests, inspections and controls) of products late, when most of the parts have been assembled. This extends the lead-time to delivery and ruins benefits from a modular product architecture; specifically when the verifications are extensive and the frequency of detected defects is high. Due to the number of product variants obtained from the modular product architecture, verifications must handle a wide range of equipment, instructions and goal values to ensure that high quality products can be delivered. As a result, the total benefits from a modular product architecture are difficult to achieve. This thesis describes a method for planning and performing verifications within a modular product architecture. The method supports companies by utilizing the defined modules for verifications already at module level, so called MPV (Module Property Verification). With MPV, defects are detected at an earlier point, compared to verification of a complete product, and the number of verifications is decreased. The MPV method is built up of three phases. In Phase A, candidate modules are evaluated on the basis of costs and lead-time of the verifications and the repair of defects. An MPV-index is obtained which quantifies the module and indicates if the module should be verified at product level or by MPV. In Phase B, the interface interaction between the modules is evaluated, as well as the distribution of properties among the modules. The purpose is to evaluate the extent to which supplementary verifications at product level is needed. Phase C supports a selection of the final verification strategy. The cost and lead-time for the supplementary verifications are considered together with the results from Phase A and B. The MPV method is based on a set of qualitative and quantitative measures and tools which provide an overview and support the achievement of cost and time efficient company specific verifications. A practical application in industry shows how the MPV method can be used, and the subsequent benefits / <p>QC 20100906</p>
456

Efficient Modeling of Modular Multilevel HVDC Converters (MMC) on Electromagnetic Transient Simulation Programs

Gnanarathna, Udana 04 September 2014 (has links)
The recent introduction of a new converter topology, the modular multilevel converter (MMC) is a major step forward in voltage sourced converter (VSC) technology for high voltage, high power applications. To obtain a multilevel ac output waveform, a large number of semiconductor switches has to be used in the converter. The number of switches in the MMC for HVDC transmission is typically two orders of magnitudes larger than that in a two or three level VSC used in earlier generation. This large device count creates a computational challenge for electromagnetic transients (EMT) simulation programs, as it significantly increases the simulation time. The purpose of this research is to investigate whether the simulation can be speeded up. This research develops an efficient, time-varying Thévenin's equivalent model for the MMC converter based on partitioning the system’s admittance matrix. EMT simulation results show that the proposed equivalent model can drastically reduce the computational time without loss of accuracy. The use of the proposed equivalent method is demonstrated by simulating a point to point MMC based HVDC transmission system successfully with more than 100 levels. This approach enables what was hitherto not practical; the modeling of large MMC based HVDC systems on personal computers. With the assumption of ideal switch operation and using an equivalent average capacitor value based approach, an average valued model of MMC is also proposed in this thesis. The average model can be accurately used in most of the system level studies. The control algorithms and other modeling aspects of MMC applications are also presented in this thesis. One of the advantages of multilevel converters is the low operating losses as the smaller switching frequency of each individual power electronics switch and the low voltage step change during each switching. Using a recently developed, time domain simulation approach, the operating losses of the MMC converter are estimated in this thesis. When comparing the MMC operating losses against the losses of two-level VSC, the power loss for the two-level VSC is found to be significantly higher than the power loss of the MMC.
457

The Modulor in the mirror /

Oliveira, Tânia Mara Guerra de January 1999 (has links)
This essay discusses Le Corbusier's Modulor through its appearance in the Poeme de l'angle droit. The Poeme reveals the architect's later thinking in a synthetic and precise way, offering precious help for its comprehension. A study of the Modulor in such context demonstrates that it was more than an attempt to develop a modular methodology. Embodied in the Poeme, the Modulor discloses Le Corbusier's struggle to create a framework for his practice, providing invaluable insights into our present condition.
458

Configurable Robot Base Design For Mixed Terrain Applications

Bayar, Gokhan 01 August 2005 (has links) (PDF)
Mobile robotics has become a rapidly developing field of interdisciplinary research within robotics. This promising field has attracted the attention of academicy, industry, several government agencies. Currently from security to personal service mobile robots are being used in a variety of tasks. The use of such robots is expected to only increase in the near future. In this study, it is aimed to design and manufacture a versatile robot base. This base is aimed to be the main driving unit for various applications performed both indoors and outdoors ranging from personal service and assistance to military applications. The study does not attempt to individually address any specific application, indeed it is aimed to shape up a robotic module that can be used in a wide range of application on different terrain with proper modification. The robot base is specifically designed for mixed terrain applications, yet this study attempts to provide some guidelines to help robot designers. The manufactured robot base is tested with tracks, wheels, and with both tracks and wheels, results are provided as guidelines to robot designers. Last but no the least, this study aims to obtain the know-how of building functional and flexible robots in Turkey by facilitating local resources as much as possible.
459

New Montgomery Modular Multiplier Architecture

Ciftcibasi, Mehmet Emre 01 January 2006 (has links) (PDF)
This thesis is the real time implementation of the new, unified field, dual&ndash / radix Montgomery modular multiplier architecture presented by SavaS et al, for performance comparison with standard Montgomery multiplication algorithms. The unified field architecture operates in both GF(p) and GF(2n). The dual radix capability enables processing of two bits of the multiplier in every clock cycle in GF(2n) mode, while one bit of the multiplier is processed in GF(p) mode. The new architecture is implemented in a Xilinx FPGA on the custom printed circuit board. The windows user interface is developed in Borland Builder environment and the ethernet interface is implemented by Ubicom IP2022 controller. The algorithms are compared from operating clock frequency, silicon area cost and multiplication time perspectives. The new architecture multiplies two times faster in GF(p) and four times faster in GF(2n), compared to the previous architectures as expected. The operand length is increased from 8 bits to 1024 bits, with the compromise of decreasing the operating clock frequency from 150 Mhz down to 15 Mhz.
460

Secure Key Establishment for Mobile Networks

Tin, Yiu Shing (Terry) January 2005 (has links)
Informal analysis of authenticated key establishment (ake) protocols was commonly accepted as the valid argument for their security in the past. Although it can provide some confidence in protocol correctness, experience has shown time and again that ake protocols are likely to contain flaws even after an informal analysis is completed. Therefore, it has become increasingly common to expect a formal analysis, and preferably a mathematical proof, of any published ake protocol in order to obtain increased confidence in its security. In this research we use an appropriate model for analysing ake protocols based on its features and properties. The model allows us to design ake protocols modularly and reuse existing protocol components. We provide a detailed description of its formalisation, operations and usage. This description also includes ways of extracting new protocol components from existing ake protocols. Following the description of the model, we propose a new unauthenticated key establishment protocol for two-party communications. By composing this protocol with authentication protocols, we can construct several new secure ake protocols. These new protocols are compared with existing protocols for their computational efficiency. The comparison shows that our new proven secure protocols are as efficient as the existing protocols with an informal security analysis. We then propose a three-party key establishment protocol which involves a trusted server and two users. We also propose a non-interactive authentication protocol and discuss it and a variant of it. These components are used to construct a secure three-party ake protocol that supports a privacy framework. This framework allows users to remain anonymous while conducting electronic transactions with an independent service provider. A new password-based authentication protocol is proposed to address the problem of authentication using passwords. This protocol carries a proof of security and satisfies a slightly relaxed definition of security. We demonstrate its application by composing it with existing key establishment protocols. To maximise its use, we modified a two-party key establishment protocol to become three-party server based. By using the server for authentication, two users within a common network domain can establish a secure session key. Only a small number of ake protocols are demonstrated in this thesis. There exist many more provably secure ake protocols that can be constructed using the protocol components presented by applying the approach of "mix and match". That is, each new component results in a number of new ake protocols depending on the number of existing components.

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