To see the other types of publications on this topic, follow the link: Heterogeneous.
Dissertations / Theses on the topic 'Heterogeneous'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Heterogeneous.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Koch, Walter V. von (Walter Victor von) 1973. "Heterogeneous synchronization." Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/46232.
Full textAbstract:
Thesis (S.B. and M.Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1998.Includes bibliographical references (p. 59-60).
by Walter V. vonKotch.
S.B.and M.Eng.
2
RUNGI, ARMANDO. "Heterogeneous firms and heterogeneous responses from economic integration: empirical studies." Doctoral thesis, Università Bocconi, 2011. https://hdl.handle.net/11565/4054218.
Full text
3
Nieva, Gabriel. "Integrating Heterogeneous Data." Thesis, Mittuniversitetet, Avdelningen för arkiv- och datavetenskap, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-29950.
Full textAbstract:
Technological advances, particularly in the areas of processing and storage have made it possible to gather an unprecedented vast and heterogeneous amount of data. The evolution of the internet, particularly Social media, the internet of things, and mobile technology together with new business trends has precipitated us in the age of Big data and add complexity to the integration task. The objective of this study has been to explore the question of data heterogeneity trough the deployment of a systematic literature review methodology. The study surveys the drivers of this data heterogeneity, the inner workings of it, and it explores the interrelated fields and technologies that deal with the capture, organization and mining of this data and their limitations. Developments such as Hadoop and its suit components together with new computing paradigms such as cloud computing and virtualization help palliate the unprecedented amount of rapidly changing, heterogeneous data which we see today. Despite these dramatic developments, the study shows that there are gaps which need to be filled in order to tackle the challenges of Web 3.0.
4
Bottomley, L. "Heterogeneous polyethylene alloys." Thesis, Brunel University, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.235021.
Full text
5
Adams, Ieuan. "Asymmetric heterogeneous hydrogenation." Thesis, University of Oxford, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.400018.
Full text
6
Meadows, G. R. "Heterogeneous redox catalysis." Thesis, Swansea University, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.638165.
Full textAbstract:
The practical importance of heterogeneous redox catalysis to many industrial processes has been well-documented over the past decade. Although there has been much technological progress in fields such as mineralogy, electrodeless plating, chlor-alkali production, photographic development, hydrometallurgy and many artificial solar to chemical energy conversion systems, the fundamental processes involved are not always fully understood. There is a need, therefore, to investigate these processes further. Chapter 3 investigates the abilities of different carbon black materials to act as catalysts for the oxidation of brine to chlorine by ceric ions. The kinetics are studied as a function of various experimental parameters, a reaction mechanism is proposed and these results are readily interpreted using an electrochemical model. Chapter 4 follows on from Chapter 3 by extending the investigation to include a study of all the three forms of crystalline carbon (graphite, diamond and C60) as chlorine catalysts. This chapter reports the first example of C60 acting as a redox catalyst. Chapter 5 reports the kinetics and mechanism of a rare example of reversible heterogeneous redox catalysis, in which the oxidation of ruthenium (II) tris (2,2'-bipyridine) ions by thallic ions in nitric acid is catalysed by a dispersion of ruthenium dioxide hydrate. The reaction kinetics fit an electrochemical model of reversible heterogeneous redox catalysis, assuming the kinetics are diffusion-controlled. Chapter 6 similarly investigates the use of a variety of platinum powder dispersions to act as catalysts for the reaction studied in Chapter 5. It also includes a study to show that inert metal oxides can be used as antiflocculants to enhance the rate of heterogeneous catalysis by platinum group metals of this reaction, as well as irreversible redox reactions, such as water and brine oxidation. Chapter 7 describes a novel route for the removal of harmful bromate ions from drinking water. The reaction kinetics are studied both in water and in the presence of organic pollutants and an electrochemical model, in which the two participating redox couples are both electrochemically irreversible, is used to interpret the observed kinetics.
7
Lu, Howard J. (Howard Jason). "Heterogeneous multithreaded computing." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/36584.
Full text
8
Jackson, Robert Owen. "Heterogeneous parallel computing." Thesis, University of Birmingham, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.366162.
Full text
9
Gambetti, Claudio <1978>. "Wireless heterogeneous networks." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2007. http://amsdottorato.unibo.it/394/1/Tesi_Gambetti_finale.pdf.
Full text
10
Gambetti, Claudio <1978>. "Wireless heterogeneous networks." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2007. http://amsdottorato.unibo.it/394/.
Full text
11
Rehman, Faisal. "Heterogeneous Embedded Network Architecture." Thesis, Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-2529.
Full textAbstract:
In this thesis we focused on high performance embedded real-time networks which are designed for systems like radar signalling processing systems, control systems etc. These high performance embedded networks consist of emerging standards like PCI Express, RapidIO, and standard Ethernet. All of these switched embedded networks communicate with each other through common gateway nodes. As these networks have different rate characteristics, maximum packet size (MTU), packet priorities, addressing schemes etc we have therefore defined the gateway nodes for these heterogeneous embedded networks which will allow these heterogeneous embedded networks to communicate with each other with the help of different translation functions. These gateway nodes allow end-to-end transmission across the heterogeneous embedded networks while keeping bound on end-to-end delay and guaranteed throughput. We need to have some flow control mechanism which will shape the traffic flow in the mentioned embedded networks and will avoid from buffer overflow.
12
Aspiotis, Evangelos. "Heterogeneous Agents and Economics." Thesis, Imperial College London, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.487994.
Full textAbstract:
We use an evolutionary psychology framework and hypothesize that men and women have heterogeneous economic preferences. In particular, we propose' that men are financially less risk averse than women. We test this supposition by calibrating the risk aversion coefficient for both sexes, using a Consumption Capital Asset Pricing Model and panel data on consumption. Our results. offer support to our hypothesis. Also, we assert that men prefer status more than women do. To assess the validity of this proposition we conduct direct tests on the structure of preferences, using panel data on life-satisfaction. The results from this exercise verify our hypothesis. We further investigate how gender differences in the preferences for status influence labour supply. To this end, we develop a static labour supply model with interdependent preferences and test for sex differences. Our results in the cross section are largely supportive of our model. However, once we control for fixed individual heterogeneity using panel data. we find no evidence of gender differences on labour supply.
13
Ghazi, Nauman. "Testing of Heterogeneous Systems." Licentiate thesis, Blekinge Tekniska Högskola, Institutionen för programvaruteknik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-00591.
Full textAbstract:
Context: A system of systems often exhibits heterogeneity, for instance in implementation, hardware, process and verification. We define a heterogeneous system, as a system comprised of multiple systems (system of systems) where at least one subsystem exhibits heterogeneity with respect to the other systems. The system of systems approach taken in development of heterogeneous systems give rise to various challenges due to continuous change in configurations and multiple interactions between the functionally independent subsystems. The challenges posed to testing of heterogeneous systems are mainly related to interoperability, conformance and large regression test suites. Furthermore, the inherent complexities of heterogeneous systems also pose challenge to the specification, selection and execution of tests. Objective: The main objective of this licentiate thesis is to provide an insight on the state of the art in testing heterogeneous systems. Moreover, we also aimed to investigate different test techniques used to test heterogeneous systems in industrial settings and their usefulness as well as to identify and prioritize different information sources that can help practitioners to define a generic search space for test case selection process. Method: The findings presented in this thesis are obtained through a controlled experiment, a systematic literature review (SLR), a case study and an exploratory survey. The purpose of systematic literature review was to investigate the existing state of art in testing heterogeneous systems and identification of research gaps. The results from the SLR further laid down the foundation of action research conducted through an exploratory survey to compare different test techniques. We also conducted an industrial case study to investigate the relevant data sources for search space initiation to prioritize and specify test cases in context of heterogeneous systems. Results: Based on our literature review, we found that testing of heterogeneous systems is considered a problem of integration and system testing. It has been observed that multiple interactions between the system and subsystems results into a testing challenge, especially when the configurations change continuously. It is also observed that current literature targets the problem of testing heterogeneous systems with multiple test objectives resulting in employing different test methods to reach a domain specific testing challenge. Using the exploratory survey, we found three test techniques to be most relevant in context of testing heterogeneous systems. However, the most frequently used technique mentioned by the practitioners is manual exploratory testing which is not a much researched topic in the context of heterogeneous systems. Moreover, multiple information sources for test selection process are identified through the case study and the survey. Conclusion: Companies engaged in development of heterogeneous systems encounter huge challenges due to multiple interactions between the system and subsystems. However, the conclusions we draw from the research studies included herein show a gap between literature and industry. Search-based testing is widely discussed in the literature but is the least used test technique in industrial practice. Moreover, for test selection process there are no frameworks that take in account all the information sources that we investigated. Therefore, to fill this gap there is a need for an optimized test selection process based on the information sources. There is also a need to study different test techniques identified through our SLR and survey and compare these techniques on real heterogeneous systems.
14
Leenders, Bram. "Heterogeneous Storage in HopsFS." Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-202970.
Full textAbstract:
In the recent years, the Apache Hadoop distributed file system (HDFS) has become increasingly popular for the storage of large data sets. Both the volume of the data and the variety of applications is unprecedented. The variety of tasks, each with its own access pattern and demands, calls for a file system that supports specialized storages for different tasks. This thesis describes the implementation of heterogeneous storage in HopsFS, a highly-available, highly-scalable version of HDFS. This makes the cluster aware of different storage types (e.g. hard disks and solid state drives) and allows users to specify preferred storage types for their data. By introducing new storage types, we build in support for storage technologies like SSDs and RAID. The latter is especially of interest, since it increases both bandwidth and reliability of the storage on individual nodes while continuing commodity hardware. Since network bandwidth is increasing orders of magnitude faster than disk bandwidth, increasing the disk throughput is of vital importance to avoid local storage becoming a bottleneck. The heterogeneous storage Application Programming Interface (API) described in this thesis offers HDFS administrators more control over their data while being compatible with the HDFS framework. Users can choose whether they want files stored on traditional disks, SSDs or more complex constructions using RAID and erasure coding.
15
Roque, Pedro. "Heterogeneous Collaborative Aerial Manipulation." Thesis, KTH, Reglerteknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-221799.
Full textAbstract:
Unmanned Vehicles are a fast-growing area of robotics due to theirvast application scenarios and ability to perform tasks otherwise impossible.A particular branch, Unmanned Aerial Vehicles, specificallymultirotors, as seen an increasing interest in research due to their mechanicalsimplicity and agility.Within AEROWORKS, UAVs are explored as aerial workers, capableof doing autonomous reconstruction of structures and transportationof payloads. This works targets heterogeneous collaborative aerialmanipulation, in which two different vehicles are used with two differentmanipulation capabilities - a manipulator and a tether - to transporta rod-like object.We consider two cases, one where the manipulator is free of actuation,and another where the manipulator is locked. Each UAV has aPID controller which gains are calculated through a linearization procedureof the system, and such that they guarantee exponential stability.Experiments provide an insight into the modeled transportationscenario and show that our controller is capable of stabilizing the system.Obemannade fordon är en växande teknik inom robotik på groundav att den kan tillämpas på många områden och uföra uppgifter somtidigare varit omöjliga. En specifik gren är obemannade flygfordon,UAV (Unmanned Aerial Vehicles). Intresset för multirotorer har ökateftersom de har en enkel och smidig konstruktion.Inom AEROWORKS, utforskas att använda UAVs som arbetareoch autonomt utföra uppgifter som att rekonstruera strukturer samttransportera object. Detta arbete inriktar sig mot att manipulera objektmed flera samarbetande drönare med som har olika förmågor att manipuleraobjekt. Två fordon där den ena är utrustad med en robotarmoch den andra en tjudra för att transportera ett stav liknande objekt.Två olika fall undersöks, dels då armen är låst samt då armen tillåtsatt röra sig. Varje UAV har en PID regulator. Förstärkningen beräknasgenom att linearisera systemet så att stabilitet garanteras. En inblicki det modelerade transportscenariot ges med experiment och vi visaratt vår regulator stabiliserar systemet.
16
Mugume, Edwin. "Green heterogeneous cellular networks." Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/green-heterogeneous-cellular-networks(e7976a91-c891-4174-abaf-18820ff1736d).html.
Full textAbstract:
Data traffic demand has been increasing exponentially and this trend will continue over theforeseeable future. This has forced operators to upgrade and densify their mobile networks toenhance their capacity. Future networks will be characterized by a dense deployment of different kinds of base stations (BSs) in a hierarchical cellular structure. However network densification requires extensive capital and operational investment which limits operator revenues and raises ecological concerns over greenhouse gas emissions. Although networks are planned to support peak traffic, traffic demand is actually highly variable in both space and time which makes it necessary to adapt network energy consumption to inevitable variations in traffic demand. In this thesis, stochastic geometry tools are used to perform simple and tractable analysis of thecoverage, rate and energy performance of homogeneous networks and heterogeneous networks(HetNets). BSs in each tier are located according to independent Poisson Point Processes(PPPs) to generate irregular topologies that fairly resemble practical deployment topologies. The homogeneous network is optimized to determine the optimal BS density and transmit power configuration that minimizes its area power consumption (APC) subject to both coverage and average rate constraints. Results show that optimal transmit power only depends on the BSpower consumption parameters and can be predetermined. Furthermore, various sleep modemechanisms are applied to the homogeneous network to adapt its APC to changes in userdensity. A centralized strategic scheme which prioritize BSs with the least number of usersenhances energy efficiency (EE) of the network. Due to the complexity of such a centralizedscheme, a distributed scheme which implements the strategic algorithm within clusters of BSsis proposed and its performance closely matches that of its centralized counterpart. It is more challenging to model the optimal deployment configuration per tier in a multi-tier HetNet. Appropriate assumptions are used to determine tight approximations of these deployment configurations that minimize the APC of biased and unbiased HetNets subject tocoverage and rate constraints. The optimization is performed for three different user associationschemes. Similar to the homogeneous network, optimal transmit power per tier also depends onBS power consumption parameters only and can also be predetermined. Analysis of the effect of biasing on HetNet performance shows appropriate biasing can further reduce the deploymentconfiguration (and consequently the APC) compared to an unbiased HetNet. In addition, biasing can be used to offload traffic from congesting and high-power macro BSs to low-power small BSs. If idle BSs are put into sleep mode, more energy is saved and HetNet EE improves. Moreover, appropriate biasing also enhances the EE of the HetNet.
17
Yang, Dan-Hui. "Homogeneous and heterogeneous sonochemistry." Doctoral thesis, Universite Libre de Bruxelles, 1992. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/212940.
Full text
18
Jong, Hayco Alexander de. "Flexible heterogeneous software systems." [S.l : Amsterdam : s.n.] ; Universiteit van Amsterdam [Host], 2007. http://dare.uva.nl/document/39606.
Full text
19
Antoni, Ľubomír, Stanislav Krajči, Ondrej Krídlo, and Lenka Pisková. "Heterogeneous environment on examples." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2013. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-113126.
Full textAbstract:
We propose a running example for heterogeneous approach based on new type of fuzzification that diversifies fuzziness of every object, fuzziness of every attribute and fuzziness of every table value in a formal context. Moreover we suggest another working examples on heterogeneous environment and provide additional utilization and illustration of this new model that allows to use Formal Concept Analysis also for heterogenenous data. An interpretation of heterogeneous formal concepts and the resulting concept lattice is included.
20
Modaressi-Esfeh, Hedieh. "Wetting on heterogeneous surfaces." Thesis, McGill University, 2001. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=38084.
Full textAbstract:
Dynamic wetting and absorption of water droplets on heterogeneous surfaces, including paper, was studied. The objective was to elucidate the role of surface heterogeneities on wetting and absorption properties of paper. To better understand the phenomena, wetting on glass slides with a controlled level of heterogeneity was investigated. Also, partially hydrophobized glass capillaries were used to simulate capillary penetration into the pores on sized paper.Dynamic wetting on paper followed a power law model with a lower rate than wetting on a smooth surface. The chemical composition of the paper surface did not affect the wetting dynamics, which was mainly affected by surface roughness in a micron scale. The super-hydrophobic properties of the sized papers were due to air entrapment in the micron-scale roughness on the surface.
Wetting and absorption of water droplets on sized paper occurred in different time scales. A pseudo-equilibrium contact angle was reached at the end of wetting just before absorption of water droplets. Increasing the surface coverage of the hydrophobic domains on paper by sizing increased the pseudo-equilibrium contact angle and delayed absorption into paper. This delay was related to partial dissolution of the surface sizing polymers in the water droplets on the surface.
The equilibrium contact angle of water droplets on partially hydrophobized glass slides was a linear function of a characteristic dimension of the hydrophobic domains and the length of the three phase contact line.
The dynamic rise of water in partially hydrophobized vertical capillaries followed two mechanisms. First, capillary rise was a function of the dynamic contact angle, changing with the velocity of the contact line. Second, local changes of the advancing contact angle due to the heterogeneities on the capillary walls lowered the capillary rise velocity. The stick (pause) and jump of the contact line was another effect of the hydrophobic domains. Capillary rise dynamics was a function of the advancing contact angle of water droplets measured on a flat glass slide with the same coverage of hydrophobic domains.
21
Forryan, Claire L. "Studies of heterogeneous systems." Thesis, University of Oxford, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.434864.
Full text
22
Davies, Trevor J. "Voltammetry at heterogeneous electrodes." Thesis, University of Oxford, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.427873.
Full text
23
Ravindranathan, Mohan Das K. "Heterogeneous intelligent control systems." Thesis, Heriot-Watt University, 1996. http://hdl.handle.net/10399/736.
Full text
24
Price, P. J. "Heterogeneous catalytic transfer hydrogenolysis." Thesis, University of Liverpool, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.372698.
Full text
25
Peixoto, Fernandes da Silva Eduardo. "Advanced heterogeneous video transcoding." Thesis, Queen Mary, University of London, 2012. http://qmro.qmul.ac.uk/xmlui/handle/123456789/3355.
Full textAbstract:
Video transcoding is an essential tool to promote inter-operability between different video communication systems. This thesis presents two novel video transcoders, both operating on bitstreams of the cur- rent H.264/AVC standard. The first transcoder converts H.264/AVC bitstreams to a Wavelet Scalable Video Codec (W-SVC), while the second targets the emerging High Efficiency Video Coding (HEVC). Scalable Video Coding (SVC) enables low complexity adaptation of compressed video, providing an efficient solution for content delivery through heterogeneous networks. The transcoder proposed here aims at exploiting the advantages offered by SVC technology when dealing with conventional coders and legacy video, efficiently reusing information found in the H.264/AVC bitstream to achieve a high rate-distortion performance at a low complexity cost. Its main features include new mode mapping algorithms that exploit the W-SVC larger macroblock sizes, and a new state-of-the-art motion vector composition algorithm that is able to tackle different coding configurations in the H.264/AVC bitstream, including IPP or IBBP with multiple reference frames. The emerging video coding standard, HEVC, is currently approaching the final stage of development prior to standardization. This thesis proposes and evaluates several transcoding algorithms for the HEVC codec. In particular, a transcoder based on a new method that is capable of complexity scalability, trading off rate-distortion performance for complexity reduction, is proposed. Furthermore, other transcoding solutions are explored, based on a novel content-based modeling approach, in which the transcoder adapts its parameters based on the contents of the sequence being encoded. Finally, the application of this research is not constrained to these transcoders, as many of the techniques developed aim to contribute to advance the research on this field, and have the potential to be incorporated in different video transcoding architectures.
26
Mounzer, Hamza. "Heterogeneous oxidation of alcohols." Thesis, University of Birmingham, 2009. http://etheses.bham.ac.uk//id/eprint/387/.
Full textAbstract:
The selective oxidation of alcohols is one of the most challenging reactions in green chemistry. While the current chemical industry uses organic and inorganic oxidants to produce carbonyl compounds, it is highly desirable to use a heterogeneous catalyst for the efficient oxidation of alcohols. The present research is focused on increasing the activity and selectivity towards the corresponding carbonyl of the heterogeneous oxidation for alcohols. The low activity of 5 wt.%Pt-1 wt. %Bi/Carbon for the oxidation of 2-octanol was investigated in a 500ml stirred tank reactor. The fast reaction rate drops dramatically from 0.23 M/hr to 0.006 M/hr after 15 minutes reaction time when heptane was used as solvent. Different possible causes such as overoxidation, leaching and poisoning were examined. It was found that the loss of high conversion rate was due to product adsorption and hence, different solvents were investigated. A mixture of 16-18% v/v dioxane in heptane was able to effectively regenerate active sites and allow a constant reaction rate of 0.07M/hr. The effects of temperature and pressure were also studied. Gas-liquid, liquid-solid and internal mass transfer effects were determined experimentally and semi-empirically. Six different Langmuir-Hinshelwood rate models were examined where a modified model based on Schuurman et al. (1992) was found to adequately describe the experimental data. The novel 2.5%Au-2.5%Pd/titania catalyst was investigated for the oxidation of benzyl alcohol. Different parameters such as catalyst oxidation state, pressure and stirrer design were studied to increase the activity and selectivity of the catalyst. The selectivity was shown to be highly dependent on the oxygen concentration. Therefore, the pressure, temperature, catalyst treatment were optimised and the reactor configuration was re-designed to enhance oxygen transport to the catalyst. While the conversion rate was unaffected by the oxygen concentration, the catalyst pre-treatment significantly increased the reaction rate. Eventually, the use of a Rushton Turbine at 20 rps with a shower disc sparger and a treated catalyst allowed the selectivity to reach 93%. The reaction could be described with a Power Law model satisfactorily. Transition Metal Oxide catalysts such as \(AgO/ SiO_2, Fe_2O_3/SiO_2, CuO/SiO_2\) and \(CuO/Al_2O_3\) were investigated as an alternative to the expensive noble metal based catalyst. However, it was shown that such catalysts are ineffective for the oxidation of different alcohols by studying the effects of different engineering parameters. The maximum conversion reached was 15% with calcined copper oxide catalyst for 1-octanol oxidation.
27
Koch, Donald Lyle. "Dispersion in heterogeneous media." Thesis, Massachusetts Institute of Technology, 1986. http://hdl.handle.net/1721.1/15207.
Full textAbstract:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 1986.MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE.
Vita.
Includes bibliographies.
by Donald Lyle Koch.
Ph.D.
28
Parker, Lynne E. (Lynne Edwards) 1961. "Heterogeneous multi-robot cooperation." Thesis, MIT Artificial Intelligence Laboratory, 1994. http://hdl.handle.net/1721.1/12187.
Full textAbstract:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1994.Cover title.
Includes bibliographical references (p. 219-227).
Supported by the Advanced Research Projects Agency of the Dept. of Defense under Office of Naval Research contracts. N00014-91-J-4038 N00014-85-K-0124 Supported by the California Institute of Technology Jet Propulsion Laboratory. 959333 Supported in part by Matsushita Research.
Lynne E. Parker.
Ph.D.
29
Pfajfar, Damjan. "Heterogeneous expectations in macroeconomics." Thesis, University of Cambridge, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.611127.
Full text
30
Antoni, Ľubomír, Stanislav Krajči, Ondrej Krídlo, and Lenka Pisková. "Heterogeneous environment on examples." Technische Universität Dresden, 2013. https://tud.qucosa.de/id/qucosa%3A26887.
Full textAbstract:
We propose a running example for heterogeneous approach based on new type of fuzzification that diversifies fuzziness of every object, fuzziness of every attribute and fuzziness of every table value in a formal context. Moreover we suggest another working examples on heterogeneous environment and provide additional utilization and illustration of this new model that allows to use Formal Concept Analysis also for heterogenenous data. An interpretation of heterogeneous formal concepts and the resulting concept lattice is included.
31
Chung, Yoen-Seung. "Sorting in heterogeneous contests." The Ohio State University, 1987. http://rave.ohiolink.edu/etdc/view?acc_num=osu1279738781.
Full text
32
Frandsen, Dallin James. "Heterogeneous Templated Grain Growth." BYU ScholarsArchive, 2018. https://scholarsarchive.byu.edu/etd/7336.
Full textAbstract:
Heterogeneous Templated Grain Growth (HTGG) is a developing method to fabricate designedcrystallographic textures of polycrystalline materials. Designed crystallographic texturesare important for enhancing desired material properties for specific applications. Four steps toHTGG have been identified: fabricating single crystal seeds, aligning seeds embedded into a powdermatrix, compacting seeds in the powder matrix, and promoting templating through sintering.Experimental research was performed on processing parameters, powder particle size and compaction,to indicate template coarsening trends during sintering. The results demonstrated thatlarger powder particles were influenced faster by the seed<'>s crystallographic orientations comparedto smaller particles. The local effects of porosity on the seed and powder interface were analyzedand this powder size effect was explained in the context of the theory of Zener pinning.
33
Recayte, Estefania <1988>. "Caching in Heterogeneous Networks." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2019. http://amsdottorato.unibo.it/8974/1/0_Thesis.pdf.
Full textAbstract:
A promising solution in order to cope with the massive request of wireless data traffic consists of having replicas of the potential requested content memorized across the network.
In cache-enabled heterogeneous networks, content is pre-fetched close to the users during network off-peak periods in order to directly serve the users when the network is congested. Caching content at the edge of heterogeneous networks not only leads to significantly reduce the traffic congestion in the backhaul link but also leads to achieve higher levels of energy efficiency. However, the good performance of a system foresees a deep analysis of the possible caching techniques. Due to the physical limitation of the caches' size and the
excessive amount of content, the design of caching policies which define how the content has to be cached and select the likely data to store is crucial.
Within this thesis, caching techniques for storing and delivering the content in heterogeneous networks are investigated from two different aspects. The first part of the thesis is focused on the reduction of the power consumption when the cached content is delivered over an Gaussian interference channel and per-file rate constraints are imposed. Cooperative approaches between the transmitters in order to mitigate the interference experienced by the users are analyzed. Based on such approaches, the caching optimization problem for obtaining the best cache allocation solution (in the sense of minimizing the average power consumption) is proposed. The second part of the thesis is focused on caching techniques at packet level with the aim of reducing the transmissions from the core of an heterogeneous network. The design of caching schemes based on rate-less codes for storing and delivering the cached content are proposed. For each design, the placement optimization problem which minimizes the transmission over the backhaul link is formulated.
34
Li, Zhen. "Transport of reactive solutes in heterogeneous porous media: Heterogeneous rate-limited mass transfer." Diss., The University of Arizona, 2000. http://hdl.handle.net/10150/284040.
Full textAbstract:
The transport of reactive solutes in the subsurface is influenced by a variety of physical and chemical processes. The processes are characteristically heterogeneous and often operate simultaneously at different temporal and spatial scales. In modeling reactive solute transport different models take different approaches, dependent on the scale of the system and the objective of the study. Two major approaches have been used to incorporate heterogeneous rate-limited mass transfer into mathematical models for solute transport. One focuses on processes operative at the microscopic scale and associated grain-scale heterogeneity, while the other stresses the macroscopic variability of the medium and the field-scale behavior of solute transport. In this work, I first examine the conceptual framework and model formulation of these two approaches in an attempt to evaluate potential commonality, then present a two dimensional numerical model that integrates the first approach with traditional stochastic modeling for reactive transport. In this model multiple processes are explicitly accounted for, including spatially variable flow, spatially variable sorption, locally heterogeneous diffusive mass transfer, locally heterogeneous rate-limited sorption, and locally heterogeneous first-order degradation. Finally, the model is used to (1) examine the individual and concurrent effects of multiple heterogeneous processes on reactive transport, and (2) evaluate the impact of microscopic-scale mass transfer heterogeneity on field-scale transport in systems for which hydraulic conductivity is spatially variable. The comparison of the two approaches shows that despite differences in conceptualization and formulation, both microscopic and macroscopic based models produce comparable behavior for smaller-scale systems. However, greater deviations are observed at larger scales. This suggests that caution should be taken when using mathematical modeling for elucidating the specific processes that may be influencing reactive-solute transport for a given system. Results from 2-D simulations of the new model reveal that inclusion of locally heterogeneous mass transfer does not appear to significantly influence the mean transport behavior for systems with field-scale heterogeneity. However, it does appear to influence low-concentration tailing. For simulations of reactive transport over extended distances, models with locally heterogeneous mass transfer may "preserve" the non-equilibrium effects associated with rate-limited mass transfer better than the models incorporating locally uniform mass transfer when both pore-scale and field-scale heterogeneity coexist.
35
Jiang, Shuaiyu. "Design of Photocatalysts for Efficient Heterogeneous and Heterogeneous/Homogeneous Photocatalytic Carbon Dioxide Reduction Systems." Thesis, Griffith University, 2021. http://hdl.handle.net/10072/403252.
Full textAbstract:
Environment and energy security issues derived from the immoderate consumption of finite fossil fuels have promoted the discovery of environment friendly and sustainable energy conversion strategy. The burning of fossil fuels led to large amount output of carbon dioxide (CO2), which can either cause global warming if emitted to the atmosphere freely or become abundant feedstock if utilised properly. Photocatalytic CO2 reduction reaction can convert CO2 into more valuable carbonaceous molecules, such as carbon monoxide (CO), methane (CH4), formic acid (HCOOH), or even alcohols, by harnessing infinite solar energy, and this process will contribute to alleviate both above issues. In this process, catalysis materials play a key role, and reasonable designed reaction system can provide supportive platform for catalysts to achieve desirable performance. Numerous studies have focused on developing advanced catalysts and various configuration of CO2 reduction. However, current CO2 reduction system are still encountering with enormous challenges, including the competition of hydrogen evolution reaction (HER), further leap in activity, diversity of products and complexity of reaction mechanism and active sites. This thesis aims to improve the performance of traditional heterogenous photocatalysis in gaseous phase CO2 reduction by enhancing the light utilization and mass transfer efficiency and develop new photosensitised homogeneousheterogenerous system for enhanced selectivity and activity in CO2 reduction.
Hierarchical hollow-shell nanomaterials have attracted numerous attentions in multidisciplinary research, especially in photocatalysis area, due to their unique structure and outstanding properties. However, current hard-templating synthesis methods are mainly capable of fabricating hierarchical hollow-shell structure composed with singular component and binary semiconductors, while show some drawbacks to synthesize more complicated compositions. Rational fabricating hierarchical hollow-shell structure composed with multinary semiconductor or semiconductors’ heterojunction remains challenging. In Chapter 2, the wide applicability of a unique one-pot hard-template method was discussed. With the strategy of fixing one component into templating agent (e.g. sucrose) at very beginning, followed by stepwise adsorption of other species, this method was capable of fabricating hierarchical hollow-shell structure composed of multinary semiconductor and semiconductors’ heterojunction. Besides, gaseous phase CO2 photoreduction reactions under high pressure condition were tested on synthesized hierarchical hollow-shell semiconductors’ heterojunction samples which achieved high selectivity and activity towards carbonaceous products.
Highly selective photocatalytic CO2 reduction into CO and methane (CH4) by solidgas interface reaction mode is achieved under ambient pressure on elaborately designed hollow sphere based TiO2/SrTiO3 heterostructures. The synthesized three-dimensional hierarchical hollow multi-shelled TiO2/SrTiO3 spheres (HoMSs-TS) are an assembly of well-organized shells composed of interconnected anatase TiO2 and perovskite SrTiO3 nanoparticles (NPs). This hierarchical structure features multiple porous shells and subunits, which not only serve to maximize light utilization, but also facilitate mass transport during the gaseous phase photocatalytic process. Moreover, the heterojunctions between TiO2 and SrTiO3 provide synergistic enhancement of the charge transfer and separation process, which is equally critically important in the selective photocatalytic CO2 reduction reaction (CO2RR). These advantages empower the HoMSs-TS to effectively suppress hydrogen evolution and ease the selective production of CO and CH4. This work is described in Chapter 3 of this thesis.
Photosensitized heterogeneous CO2 reduction (PHCR), especially the Ru-Co based PHCR system, has emerged as a promising visible-photocatalytic photocatalysis system for converting CO2 into value-added chemicals, however, challenged by the hydrogen evolution reaction (HER) induced low selectivity. Chapter 4 of this thesis reports a PHCR system that couples Ru(bpy)3^2+ homogeneous sensitizer with (001) faceted ultrathin LiCoO2 nanosheets heterogeneous photocatalyst with completely suppressed HER to yield 100% carbonaceous products. The experimental and theoretical studies reveal that the favored CO2 adsorption on the exposed Li on (001) faceted LiCoO2 surface is responsible for the suppressed HER.
Despite recent progress in discovering various photocatalysts, realizing high performance in sensitised homo-hetero CO2 reduction and disclosing CO2 activation site remain challenging. In the work of Chapter 5, we report the synergistic effect of superficial Co-O nano layer and heterogenous Co metallic in enhancing PHCR system. The conductive heterogenous cobalt metallic core composed of face-centred cubic (fcc)cubic Co and hexagonal closest packed (hcp) Co was formed by heat treatment of Co3O4 in reductive atmosphere and can effectively improve the conductivity of photogenerated electron. Moreover, an in situ formed thin oxide shell on the surface provided active sites for CO2 reduction reaction. Owing to the synergistic effect, the performance in photosensitised CO2 reduction into CO is about 1.7 times comparing to that of Co3O4 nanosheets under the same reaction condition. This discovery provides a promising approach for the design of other materials for energy conversion.
This thesis significantly contributes innovative knowledge in material science and CO2 reduction system through: (i) designing novel 3D structured heterogeneous photocatalyst with high photocatalytic CO2 reduction performance toward CO and CH4; (ii) developing gaseous phase CO2 reduction to suppress hydrogen evolution reaction (HER); (iii) reviewing the development of photosensitised homogeneous-heterogeneous CO2 reduction, and developing new approach to improve the selectivity by manipulating exposed ion as active site; (iv) probing the in situ formation of oxidised nanolayer around metallic core and investigating the synergetic effect of interface of oxidised layer and heterogenous metallic core in improving CO2 reduction performance in PHCR reaction system.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Environment and Sc
Science, Environment, Engineering and Technology
Full Text
36
Rackl, Günther. "Monitoring and managing heterogeneous middleware." [S.l.] : [s.n.], 2001. http://deposit.ddb.de/cgi-bin/dokserv?idn=962067164.
Full text
37
Secchi, Alessandro. "Heterogeneous Effects of Monetary Policy." Doctoral thesis, Universitat Pompeu Fabra, 2005. http://hdl.handle.net/10803/7425.
Full textAbstract:
The main objective of this thesis is to offer empirical evidence in support of the hypothesis that differences in firms' balance sheet structures may generate heterogeneous responses to monetary policy innovations. To this end in the second, introductory, chapter we start providing some evidence in favor of a large degree of heterogeneity in the asset and liability side of the balance sheet structure of manufacturing firms belonging to different European countries and different size classes. This static comparison is complemented with a quantitative assessment of the sensitivity of asset and liability items to business cycle conditions.In the third chapter we focus on a specific dimension along which the presence of heterogeneities in the balance sheet structure may induce different responses to a monetary policy action. In particular we address the existence of a channel of transmission of monetary policy, the cost-channel, that operates through the effect of interest expenses on the marginal cost of production. Such a channel is based on an active role of net working capital (inventories, plus trade receivables, less trade payables) in the production process and on the fact that variations in interest rate and credit conditions alter firms' short-run ability to produce final output by investing in net working capital. It has been argued that this mechanism may explain the dimension of the real effects of monetary policy, give a rationale for the positive short-run response of prices to rate increases (the "price puzzle") and call for a more gradual monetary policy response to shocks. The analysis is based on a unique panel, that includes about 2,000 Italian manufacturing firms and 14 years of data on individual prices and interest rates paid on several types of debt. We find robust evidence in favor of the presence of a cost-channel of monetary policy transmission, proportional to the amount of working capital held by each firm and with a size large enough to have non-trivial monetary policy implications.
The empirical analysis of chapter three is based on the hypothesis that the type of heterogeneity that produces different firm level responses to an interest rate variation is well defined and measurable. On the contrary, most of the empirical literature that tests for the existence of heterogeneous effects of monetary policy on firms' production or investment choices is based on an ad hoc assumption of the specific firm level characteristic that should distinguish more sensitive from less sensitive firms. A similar degree of arbitrariness is adopted in selecting the number of classes of firms characterized by different responses to monetary policy shocks as well as in the selection of the cutoff points. The objective of chapter four is to apply a recent econometric methodology that building on data predictive density provides a well defined criteria to detect both the "optimal" dimension along which analyze firms' responses to monetary policy innovations and the "optimal" endogenous groups. The empirical analysis is focused on Italian manufacturing firms and, in particular, on the response of inventory investment to monetary policy shocks from 1983 to 1998. The main results are the following. In strike contrast with what is normally assumed in the literature in most of the cases it turns out that the optimal number of classes that is larger than two. Moreover orderings that are based on variables that are normally thought to be equivalent proxies for the size of the firm (i.e. turnover, total assets and level of employment) do not lead neither to the same number of groups nor to similar splitting points. Finally even if endogenous clusters are mainly characterized by different degrees of within group heterogeneity, with groups composed by smaller firms showing the largest dispersion, there also exist important differences in the average effect of monetary policy across groups. In particular the fact that some of the orderings do not show the expected monotonicity between the rank and the average effect appears to be one of the most remarkable aspects.
38
Pimentel, Niño Maria Alejandra. "Video adaptation over heterogeneous networks." Doctoral thesis, Universitat Autònoma de Barcelona, 2014. http://hdl.handle.net/10803/283931.
Full textAbstract:
Los servicios de video hoy en día hacen parte de nuestras interacciones cotidianas y aportan la mayor parte del tráfico en la red. Su uso más amplio incluye escenarios fuera de lo común como lo son la ayuda en emergencias o en telemedicina. Por otra parte, las demandas de los usuarios de tales servicios, en términos de experiencia usuario, sigue en aumento, llevando a requerimientos más especializados de Calidad de Experiencia ( QoE en ínglés). Garantizar cierto nivel de satisfacción de usuario en escenarios exigentes donde las redes a disposición son heterogéneas continua siendo in problema abierto.
Los objetivos principales de esta tesis han sido: 1) proponer un marco de trabajo para networking heterogéneo que permita la transmisión de video de manera impecable a través de redes heterogéneas, 2) proponer un marco centrado en el usuario, para transmitir video que sea coherente con el networking heterogéneo, y 3) diseñar un modelo y solución completos para ofrecer video adaptativo tal que se cumplan los requerimientos de satisfacción de usuario.
A continuación se presentan las contribuciones de esta tesis que cumplen los tres objetivos trazados.
Primero, proponemos modelar las redes heterogéneas desde un ángulo holístico. La metodología de este diseño holístico de sistema está basado en dos conceptos novedosos. En primer lugar, proveer un marco a través del cual las instancias de red pueden ser modeladas para garantizar generalidad y robustez. En segundo lugar, caracterizar de manera única las instancias de red a través de su min-cut. La ventaja de este marco es que puede verse como un modelo de sistema subyacente que garantiza una impecable transmisión de contenido sin importar la instancia de red. Esto es posible formulando una optimización cross-layer para transmisión de contenido, coherente con la filosofía de networking centrada en la información (information-centric networking).
Segundo, proponemos un marco para video adaptativo impulsado por el QoE, basado en una formulación de optimización cross-layer. El algoritmo resultante permite la adaptación de video y se basa en los retardos de redes variantes en el tiempo, por lo tanto tiene en cuenta las restricciones de redes con retardos largos y las dificultades de establecer un camino de retorno que permita la adaptabilidad a los cambios en la red. Esta solución se ha evaluado sistemáticamente, tanto en entornos emulados como en una solución complemente implementada experimentalmente.
Tercero, proponemos la contribución principal de esta tesis: un modelo completo centrado en el usuario, que ofrece servicios de video en redes heterogéneas. El problema de borrado de paquetes y de congestión en las redes sin garantías (best-effort) es desacoplado para así hacerlos coincidir con los efectos respectivos que degradan el video. Esto permite la formulación de dos problemas de optimización, en tiempo (fotogramas congelados) y espacio (artefactos en la imagen). La solución completa además una novedosa dimensión semántica coherente con information-centric networking, que propone reflejar las necesidades perceptuales del usuario final. Probamos las ventajas de nuestro diseño para escenarios donde el video es necesario para adquirir conciencia de situaciones (situation awareness), donde se usan comúnmente redes heterogéneas y mostramos ganancias considerables en términos de reducción de los efectos de la congestión y el borrado de paquetes, mientras que mejoramos el QoE y cumplimos las demandas perceptuales de los usuarios.Video services have become part of everyday interactions and contribute to a major portion of network traffic. Their broader usage includes out-of-the-ordinary scenarios as aid in emergencies, or telemedicine. Moreover, user demands of such services in terms of overall user experience continue to increase, leading to more specialized Quality of Experience (QoE) requirements. Guaranteeing a level of satisfaction to the user in challenging scenarios where the alternative networks are heterogeneous in nature continues to be an open issue. The main objectives of this thesis have been to: 1) propose a framework for heterogeneous networking that allows for a seamless delivery of video content along diverse heterogeneous networks, 2) propose a user-centric framework for video transmission in line with heterogeneous networking, and 3) design a complete model and solution to provide video adaptation in heterogeneous networks such that it meets the requirements for user satisfaction. The contributions of this thesis, such that the three objectives are met are as follows. First, we propose to model heterogeneous networks with a holistic approach. The methodology of this holistic system design is based on two novel concepts. On one hand, to provide a framework by which heterogeneous network instances can be modeled to guarantee generality and robustness. On the other hand, to uniquely characterize the network instances via their min-cut. The strength of this framework is its usage as an underlying system model that can guarantee seamless content delivery regardless of the network instance. The latter is possible by formulating a general cross-layer optimization for content delivery, coherent to information-centric networking philosophy. Second, we propose a QoE-driven adaptive video framework, based on a cross-layer optimization formulation. The derived adaptive video algorithm for time-variant networks is delay-driven, hence contemplates the constraints of long-delayed networks and the challenges of establishing a feedback loop to enable the network adaptability. The framework is evaluated systematically, in both an emulation and a fully implemented experimental environment. Third, we propose the main contribution of this thesis: a complete model to provide user-centric video services in heterogeneous networks. The problem of combined erasures and congestion in best effort network is decoupled to match the specific degrading effects on the video. This allows for two separate QoE driven optimization approaches in time (freezes) and space (artifacts) domain. The complete solution offers a feasible dynamic streaming adaptation that suits constraint heterogeneous networks such as satellite. The performance is evaluated through a novel QoE three-dimensional analysis. The overall solution contemplates a novel semantical dimension, in line with information-centric networking, with an unexplored take on semantics that intends to reflect on the perceptual needs of the end user. We prove the strength of our design for the situation awareness scenario, where heterogeneous networks are often used, and show substantial gain in terms of mitigation of the effects of congestion and erasures while improving QoE and achieving the expected user's perceptual demands.
39
Alm, Oscar. "Heterogeneous Photolytic Synthesis of Nanoparticles." Doctoral thesis, Uppsala University, Department of Materials Chemistry, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-8256.
Full textAbstract:
Nanoparticles of iron, cobalt and tungsten oxide were synthesised by photolytic laser assisted chemical vapour deposition (LCVD). An excimer laser (operating at 193 nm) was used as an excitation source. The LCVD process, was monitored in situ by optical emission spectroscopy (OES). The synthesised particles were further analysed using transmission electron spectroscopy (TEM), X-ray diffraction (XRD), high resolution scanning electron microscopy (HRSEM), X-ray fluorescence spectroscopy (XRF), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy.
Iron and cobalt single crystalline nanoparticles were synthesized using ferrocene and cobaltocene precursors. The diameter of the particles could be tailored by the experimental parameters (e.g., partial pressure and laser power) and were in the range 1 - 50 nm in diameter. In both cases, the particles were covered by a carbon shell, typically 7 nm thick. A thin graphitic layer was observed at the interface metal-carbon. Amorphous carbon was deposited on top of the graphitic carbon. Particle temperature, reaching the boiling point of the respective metal, was observed by OES of the thermal emission during the laser-induced particle formation process (and subsequent heating). Both bcc and fcc Fe phases were formed, both hcp and fcc for the Co phases. Size dependent magnetic properties were observed using superconducting quantum interference device (SQUID) measurements, where super-paramagnetic magnetic domains dominated for d < 10 nm. The iron particles were further processed, whereby the amorphous shell was removed by refluxing in nitric acid. In a subsequent step, the graphitic surface was functionalized by attaching an octyl ester, rendering the particles hydrophobic.
Tungsten oxides were synthesized from combinations of WF6/H2/O2 as precursors. No particles could be deposited if H2 was removed from the gas-mixture. The as-deposited oxide nanoparticle film was amorphous. A monoclinic WO3 particle film could be achieved by annealing the amorphous oxide. Above 400°C, the oxide particles increased in size from ca. 20 nm to 60 nm through coalescence. The gas-sensing properties of the tungsten oxide were tested by conductance measurements using H2S as analyte. The sensitivity of the amorphous oxide nanoparticle film was found to be superior to that of a crystalline oxide nanoparticle film.
40
Lichtenberg, Julia. "Corporate Taxation of Heterogeneous Firms." Diss., lmu, 2010. http://nbn-resolving.de/urn:nbn:de:bvb:19-111740.
Full text
41
Sharma, Gunjana. "Heterogeneous Technologies for Microfluidic Systems." Doctoral thesis, Uppsala universitet, Mikrosystemteknik, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-131109.
Full textAbstract:
In this thesis, conventional and unconventional technologies have been studied and combined in order to make heterogeneous microfluidics with potential advantages, especially in biological applications. Many conventional materials, like silicon, glass, thermoplastic polymers, polyimide and polydimethylsiloxane (PDMS) have been combined in building heterogeneous microfluidic devices or demonstrators. Aside from these materials, unconventional materials for microfluidics such as stainless steel and the fluoroelastomer Viton have been explored. The advantages of the heterogeneous technologies presented were demonstrated in several examples: (1) For instance, in cell biology, surface properties play an important role. Different functions were achieved by combining microengineering and surface modification. Two examples were made by depositing a Teflon-like film: a) a non-textured surface was made hydrophobic to allow higher pressures for cell migration studies and b) a surface textured by ion track technology was even made super-hydrophobic. (2) In microfluidics, microactuators used for fluid handling are important, e.g. in valves and pumps. Here, microactuators that can handle high-pressures were presented, which may allow miniaturization of high performance bioanalyses that until now have been restricted to larger instruments. (3) In some applications the elastomer PDMS cannot be used due to its high permeability and poor solvent resistivity. Viton can be a good replacement when elasticity is needed, like in the demonstrated paraffin actuated membrane.(4) Sensing of bio-molecules in aquatic solutions has potential in diagnostics on-site. A proof-of-principle demonstration of a potentially highly sensitive biosensor was made by integrating a robust solidly mounted resonator in a PDMS based microfluidic system. It is concluded that heterogeneous technologies are important for microfluidic systems like micro total analysis systems (µTAS) and lab-on-chip (LOC) devices.
42
Meyer, Jan Christian. "Performance Modeling of Heterogeneous Systems." Doctoral thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for datateknikk og informasjonsvitenskap, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-19705.
Full textAbstract:
As the complexity of parallel computers grows, constraints posed by the construction of larger systems require both greater, and increasingly non-linear, parameter sets to model their behavior realistically. These heterogeneous characteristics create a trade-off between the complexity and accuracy of performance models, creating challenges in utilizing them for design decisions. In this thesis, we take a bottom-up approach to realistically model software and hardware interactions, by composing system models from simpler, linear models, which allow parts of the analysis to be automated. We associate empirically benchmarked platform performance metrics with the core elements in a variant of bulk-synchronous execution, aiming to quantify application performance, and associated potential for computation and communication overlap on SMP clusters. The original bulk-synchronous performance model is introduced, and we identify areas of computation and communication where its abstractions impede realistic models of contemporary hardware. These are addressed independently, using experimental evidence to develop a representation collecting computation kernel characteristics and pairwise communications in matrices, to combine into a system model. As bulk-synchronous execution strongly depends on periodic, global synchronization, we develop a cost model for it by combining latency measurements with a parametric representation of signalling patterns, and experimentally verify the resulting predictions for three common algorithms. We describe a design to implement the BSPLib programming interface, combining threads and message-passing parallelism to achieve overlap on commodity cluster platforms, implementing its one-sided communication primitives using out-of-band control messages. We augment and validate the cost model of one adapted synchronization algorithm with the corresponding bandwidth requirement, completing a framework for modeling BSPLib program performance. Finally, we test the utility of this framework as a proof-of-concept for guiding software performance adaptations, using two cases. First, we use the latency terms to automatically generate synchronization operations, using model predictions to generate customized patterns with respect to platform topology, showing that the resulting algorithms equal or outperform the system defaults. Second, the strong scaling characteristics of a 5-point stencil code is compared for three implementations. Experiments show the performance overhead of our implementation, but also its capability for predicting program cost, including parameter values to optimize for balanced overlapping of computation and communication.
43
Svengren, Henrik. "Water splitting by heterogeneous catalysis." Doctoral thesis, Stockholms universitet, Institutionen för material- och miljökemi (MMK), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-148181.
Full textAbstract:
A sustainable solution for meeting the energy demands at our planet is by utilizing wind-, solar-, wave-, thermal-, biomass- and hydroelectric power. These renewable and CO2 emission-free energy sources are highly variable in terms of spatial and temporal availability over the Earth, introducing the need for an appropriate method of storing and carrying energy. Hydrogen has gained significant attention as an energy storage- and carrier media because of the high energy density that is exploited within the ‘power-to-gas’ process chain. A robust way of producing sustainable hydrogen is via electrochemical water splitting. In this work the search for new heterogeneous catalyst materials with the aim of increasing energy efficiency in water splitting has involved methods of both electrochemical water splitting and chemical water oxidation. Some 21 compounds including metal- oxides, oxofluorides, oxochlorides, hydroxide and metals have been evaluated as catalysts. Two of these were synthesized directly onto conductive backbones by hydrothermal methods. Dedicated electrochemical cells were constructed for appropriate analysis of reactions, with one cell simulating an upscale unit accounting for realistic large scale applications; in this cell gaseous products are quantified by use of mass spectrometry. Parameters such as real time faradaic efficiency, production of H2 and O2 in relation to power input or overpotentials, Tafel slopes, exchange current density and electrochemical active surface area as well as turnover numbers and turnover frequencies have been evaluated. Solubility, possible side reactions, the role of the oxidation state of catalytically active elements and the nature of the outermost active surface layer of the catalyst are discussed. It was concluded that metal oxides are less efficient than metal based catalysts, both in terms of energy efficiency and in terms of electrode preparation methods intended for long time operation. The most efficient material was Ni-Fe hydroxide electrodeposited onto Ni metal foam as conductive backbone. Among the other catalysts, Co3Sb4O6F6 was of particular interest because the compound incorporate a metalloid (Sb) and redox inert F and yet show pronounced catalytic performance. In addition, performance of materials in water splitting catalysis has been discussed on the basis of results from electron microscopy, solubility experiments and X-ray diffraction data.
44
Khan, Shahid Amin. "Phase transformations in heterogeneous steels." Thesis, University of Cambridge, 1990. https://www.repository.cam.ac.uk/handle/1810/221888.
Full text
45
Alheid, Amani Abdullatif. "Multipath TCP over heterogeneous environments." Thesis, University of Bristol, 2017. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.720819.
Full text
46
Sanchez, Mathieu. "Distance based heterogeneous volume modelling." Thesis, Bournemouth University, 2015. http://eprints.bournemouth.ac.uk/24521/.
Full textAbstract:
Natural objects, such as bones and watermelons, often have a heterogeneous composition and complex internal structures. Material properties inside the object can change abruptly or gradually, and representing such changes digitally can be problematic. Attribute functions represent physical properties distribution in the volumetric object. Modelling complex attributes within a volume is a complex task. There are several approaches to modelling attributes, but distance functions have gained popularity for heterogeneous object modelling because, in addition to their usefulness, they lead to predictability and intuitiveness. In this thesis, we consider a unified framework for heterogeneous volume modelling, specifically using distance fields. In particular, we tackle various issues associated with them such as the interpolation of volumetric attributes through time for shape transformation and intuitive and predictable interpolation of attributes inside a shape. To achieve these results, we rely on smooth approximate distance fields and interior distances. This thesis deals with outstanding issues in heterogeneous object modelling, and more specifically in modelling functionally graded materials and structures using different types of distances and approximation thereof. We demonstrate the benefits of heterogeneous volume modelling using smooth approximate distance fields with various applications, such as adaptive microstructures, morphological shape generation, shape driven interpolation of material properties through time and shape conforming interpolation of properties. Distance based modelling of attributes allows us to have a better parametrization of the object volume and design gradient properties across an object. This becomes more important nowadays with the growing interest in rapid prototyping and digital fabrication of heterogeneous objects and can find practical applications in different industries.
47
Feng, Jianwen. "Probabilistic modelling of heterogeneous media." Thesis, Swansea University, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.644724.
Full text
48
El, Solh Tarek. "Heterogeneous catalyst for methane reforming." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0007/MQ30748.pdf.
Full text
49
Gammage, Justin Wilkinson D. S. "Damage in heterogeneous aluminum alloys /." *McMaster only, 2002.
Find full text
50
Boyd, David William. "Vertical restraints with heterogeneous retailers." Connect to resource, 1991. http://rave.ohiolink.edu/etdc/view.cgi?acc%5Fnum=osu1271851807.
Full text