• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 256
  • 71
  • 63
  • 52
  • 29
  • 13
  • 12
  • 8
  • 8
  • 6
  • 4
  • 3
  • 3
  • 3
  • 2
  • Tagged with
  • 603
  • 142
  • 133
  • 106
  • 93
  • 82
  • 59
  • 57
  • 56
  • 50
  • 44
  • 44
  • 42
  • 42
  • 40
  • 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.
151

Mixed-fidelity prototyping of user interfaces

Petrie, Jennifer 08 February 2006 (has links)
<p> This research presents a new technique for user interface prototyping, called mixed-fidelity prototyping. Mixed-fidelity prototyping combines low-, medium-, and high-fidelity interface elements within a single prototype in a lightweight manner, supporting independent refinement of individual elements. The approach allows designers to investigate alternate designs, including more innovative designs, and elicit feedback from stakeholders without having to commit too early in the process. As well, the approach encourages collaboration among a diverse group of stakeholders throughout the design process. For example, individuals who specialize in specific fidelities, such as high-fidelity components, are able to become involved earlier on in the process. </p> <p> We developed a conceptual model called the Region Model and implemented a proof-of-concept system called ProtoMixer. We demonstrated the mixed-fidelity approach by using ProtoMixer to design an example application. </p> <p> ProtoMixer has several benefits over other existing prototyping tools. With ProtoMixer, prototypes can be composed of multiple fidelities, and elements are easily refined and transitioned between different fidelities. Individual elements can be tied into data and functionality, and can be executed inside prototypes. As well, traditional informal practices such as sketching and storyboarding are supported. Furthermore, ProtoMixer is designed for collaborative use on a high-resolution, large display workspace. </p>
152

Digitally-Assisted Mixed-Signal Wideband Compressive Sensing

Yu, Zhuizhuan 2011 May 1900 (has links)
Digitizing wideband signals requires very demanding analog-to-digital conversion (ADC) speed and resolution specifications. In this dissertation, a mixed-signal parallel compressive sensing system is proposed to realize the sensing of wideband sparse signals at sub-Nqyuist rate by exploiting the signal sparsity. The mixed-signal compressive sensing is realized with a parallel segmented compressive sensing (PSCS) front-end, which not only can filter out the harmonic spurs that leak from the local random generator, but also provides a tradeoff between the sampling rate and the system complexity such that a practical hardware implementation is possible. Moreover, the signal randomization in the system is able to spread the spurious energy due to ADC nonlinearity along the signal bandwidth rather than concentrate on a few frequencies as it is the case for a conventional ADC. This important new property relaxes the ADC SFDR requirement when sensing frequency-domain sparse signals. The mixed-signal compressive sensing system performance is greatly impacted by the accuracy of analog circuit components, especially with the scaling of CMOS technology. In this dissertation, the effect of the circuit imperfection in the mixed-signal compressive sensing system based on the PSCS front-end is investigated in detail, such as the finite settling time, the timing uncertainty and so on. An iterative background calibration algorithm based on LMS (Least Mean Square) is proposed, which is shown to be able to effectively calibrate the error due to the circuit nonideal factors. A low-speed prototype built with off-the-shelf components is presented. The prototype is able to sense sparse analog signals with up to 4 percent sparsity at 32 percent of the Nqyuist rate. Many practical constraints that arose during building the prototype such as circuit nonidealities are addressed in detail, which provides good insights for a future high-frequency integrated circuit implementation. Based on that, a high-frequency sub-Nyquist rate receiver exploiting the parallel compressive sensing is designed and fabricated with IBM90nm CMOS technology, and measurement results are presented to show the capability of wideband compressive sensing at sub-Nyquist rate. To the best of our knowledge, this prototype is the first reported integrated chip for wideband mixed-signal compressive sensing. The proposed prototype achieves 7 bits ENOB and 3 GS/s equivalent sampling rate in simulation assuming a 0.5 ps state-of-art jitter variance, whose FOM beats the FOM of the high speed state-of-the-art Nyquist ADCs by 2-3 times. The proposed mixed-signal compressive sensing system can be applied in various fields. In particular, its applications for wideband spectrum sensing for cognitive radios and spectrum analysis in RF tests are discussed in this work.
153

A Similarity-based Data Reduction Approach

Ouyang, Jeng 07 September 2009 (has links)
Finding an efficient data reduction method for large-scale problems is an imperative task. In this paper, we propose a similarity-based self-constructing fuzzy clustering algorithm to do the sampling of instances for the classification task. Instances that are similar to each other are grouped into the same cluster. When all the instances have been fed in, a number of clusters are formed automatically. Then the statistical mean for each cluster will be regarded as representing all the instances covered in the cluster. This approach has two advantages. One is that it can be faster and uses less storage memory. The other is that the number of new representative instances need not be specified in advance by the user. Experiments on real-world datasets show that our method can run faster and obtain better reduction rate than other methods.
154

Innovation-diffusion processes in urban design movements: application of the model-prototype-adaptation framework to new urbanism and neighborhood development practices in Atlanta

Kim, Jaecheol 27 August 2010 (has links)
This dissertation investigates the transitions of urban design models in practice: the ways in which practitioners have adopted the urban design models and the factors that have influenced such adoption. In particular, this dissertation focused on the unexpected consequences of the adaptations of urban design models and distinguished these effects from those stemming from the inherent limitations of urban design models themselves. The major goal of this dissertation is to clarify the patterns of the transitions associated with urban design models in practice (particularly adaptation) to ensure a better understanding their impact on the urban environment. However, the transitions of urban design models in practice are complex phenomena that multiple actors with diverse interests have participated in and implemented numerous principles of the models over a long period of time and in diverse contexts. Therefore, to minimize such complexities while capturing important elements of the diffusion and adaptation processes, this dissertation presented a theoretical framework, the Model-Prototype-Adaptation (MPA) framework, based on recurring patterns of urban design movements. In the MPA framework, a "model" refers to an integrated set of urban design principles derived from a consensus of opinion of the enthusiastic proponents of an urban design movement; "prototypes" are projects developed by enthusiastic proponents who have strong commitment to the model and the movement; and "adaptations" are projects developed by eclectic followers who have weak commitment to the model and the movement and take advantage of the model for their interests and concerns. With these three key elements, the MPA framework hypothesizes two distinct transitions of urban design models in practice: "evolution," the developmental transition from old prototypes to new prototypes by enthusiastic proponents seeking to more effectively embody the model; and "divergence," a "watered down" application of the model in practice by eclectic followers responding to external factors such as market forces. This dissertation fleshed out the proposed basic MPA framework with historical reviews of the three urban design movements (Garden City, City Beautiful, and Modern) and a literature review of innovation-diffusion theories. In particular, the literature review focused on theories that present major factors influencing the adoption of innovations. The theories suggested that the ways in which adopters, who have different innovativeness and roles, perceive the attributes of innovations influence their decisions to adopt the innovations. In addition to the theoretical construction of the MPA framework, this dissertation presented a comparative case study with New Urbanist practices to test the MPA framework in a real world context. In particular, "divergence" of New Urbanism principles was examined specifically through a comparison of the six matched prototype-adaptation pairs of neighborhood developments in the Atlanta area. The case study first hypothesized three predictions about the perceptions and implementation of New Urbanism principles based on the MPA framework, that is, 1) enthusiastic proponents of New Urbanism perceive New Urbanism principles more positively than eclectic followers; 2) prototypes developed by enthusiastic proponents incorporate more New Urbanism principles and do so more thoroughly than adaptations developed by eclectic followers; and 3) New Urbanism principles that actors perceive more positively are implemented more often and more thoroughly. Data for the case study have been collected through interviews, surveys, field observations, planning documents, and local periodicals. The methods of analysis that were used in this study were pattern matching between predictions and observations, the explanation-building for the findings from pattern matching based on detailed contextual information derived from each case, and finally, cross-case synthesis. The comparative analysis showed that the case observations generally confirmed the three predictions. For example, among the New Urbanism principles, the "creation of an identifiable neighborhood" was perceived the most positively and also implemented the most often and thoroughly by both the enthusiastic proponents and the eclectic followers while "access to public transit" was perceived the least positively and implemented least often by both groups. In addition to the general confirmation of the three predictions, the analysis also revealed numerous unexpected findings, and efforts to build explanations for such findings based on the detailed contexts of each case yielded several important insights: the issue of compatibility between the thorough implementation of the New Urbanism model and the supply of affordable housing; the possibility of positive externalities from the proximity of prototypes to adaptations; two distinct flexibility arguments--flexibility for incremental accomplishment and that for contexts; the extent of public-private partnerships that broaden the influence of the New Urbanism principles beyond project boundaries; and communication problems between enthusiastic proponents and eclectic followers.
155

Controlling a Robot Hand in Simulation and Reality

Birgestam, Magnus January 2008 (has links)
<p>This master thesis was made at the Institute of Technology Stockholm and is a part of a robot hand project called 10-X with the aim to develop a low-cost robot hand that is light and strong.</p><p>The project specification is to further improve the ability to control the robot hand in a user friendly way. This has been done by implementing a controller, earlier used and developed at KTH, which is intuitive and easy to customize after the needs in different kinds of grasps. To make the controller easy to use an user interface has been made.</p><p>Before the implementation of the controller was made on the real hand it was tested and development on a simulation created in MATLAB/simulink with help from a graphic physics engine called GraspIt! The movement of the robot finger is effected of the force from a leaf spring and a tendon that bends the finger. Also the finger is exposed of contact forces and all these components had to be modeled in the simulation to make the finger act properly.</p> / <p>Detta examensarbete är genomfört på KTH Stockholm och är en del av ett projekt, kallat 10-X, vars syfte är att utveckla och ta fram en robothand som är lätt och stark samtidigt som den är billig.</p><p>Projektets målsättning är att vidare förbättra och utveckla möjligheten att kontrollera robothanden på ett användarvänligt sätt. Detta har gjorts genom att implementera en regulator, tidigare utvecklad och använd på KTH, som är instruktiv och lätt att anpassa efter olika typer av grepp. För att göra regulatorn enkel att använda har ett användargränssnitt skapats.</p><p>Innan regulatorn implementerades på den riktiga robothanden utvecklades och testades den på en simuleringsmodell, skapad i MATLAB/simulink med hjälp av en grafisk fysikmotor GraspIt! Rörelsen hos ett robotfinger påverkas av krafter från en bladfjäder och den lina som böjer fingret. Fingret utsätts också för kontaktkrafter och alla dessa komponenter blev modellerade i simulatorn för att få fingret att bete sig korrekt.</p>
156

SIG ET TÉLÉDÉTECTION POUR L'ÉTUDE DE L'ENSABLEMENT<br />DANS UNE ZONE ARIDE : LE CAS DE LA WILAYA DE NAÂMA (ALGÉRIE).

Bensaid, Abdelkrim 27 June 2006 (has links) (PDF)
En Algérie, près de 20 millions d'hectares sont menacés par l'érosion éolienne. Depuis longtemps, le phénomène de l'érosion éolienne et ses effets néfastes sur le milieu naturel et l'environnement, constituent un sérieux problème, surtout dans les zones arides du pays. Ces dernières années, suite à l'exploitation irrationnelle des ressources naturelles (fourragères) et à la mise en culture des terres fragiles (défrichement) ce processus s'est particulièrement accentué. L'ampleur de la dégradation dans la zone aride de la wilaya de Naâma a engendré une situation nouvelle caractérisée par la réduction du couvert végétal, la diminution de la production ainsi que l'extension de l'ensablement rapide sur les zones mises en valeur. <br /><br />A travers cette étude, nous avons essayé de montrer d'une part, le potentiel de l'utilisation de la télédétection et du système d'information géographique pour la caractérisation de l'état de l'occupation du sol et son évolution spatio-temporelle à partir des traitements effectués sur une série d'images satellitaires de Landsat de différentes dates (1972, 1987 et 2002). <br />D'autre part, de mettre à la disposition des utilisateurs potentiels et des décideurs les informations sur l'état de l'environnement et les ressources naturelles de ces zones, via la mise en place d'un prototype intégré dans un système d'information géographique. Le prototype ainsi développé est basé sur le principe du double prototypage. Le système sera un outil d'aide à la décision, utile pour la gestion des phénomènes naturels, et plus particulièrement la dégradation des sols et l'ensablement des terres de la wilaya de Naâma.
157

Web-based highway maintenance functions prioritizing system using analytical hierarchy process

Liu, Jin, master of science in engineering 30 October 2012 (has links)
The Texas Department of Transportation has been experiencing maintenance budget fluctuations recently. The shortage of budget has a negative impact on the agency’s maintenance strategies and results in the undesirable deterioration of highway conditions increasing the risk towards both road users and the agency. This paper aims at developing a methodology to minimize the impact of budget fluctuation by quantifying the risk of not performing a maintenance activity and identifying the priority of maintenance activities based on the quantified risk. With the help of maintenance experts from TxDOT, four maintenance objectives and 16 maintenance function groups were identified and a hierarchy structure was developed based on the objectives and function groups. Four pilot districts were selected to represent the different demographic and climatic regions in Texas and maintenance experts were selected from the four districts to participate in the workshop. The Overall Relative Weights of 16 maintenance function groups were determined based on the individual evaluator’s judgments using the Analytical Hierarchy Process. To determine if the four pilot districts give different relative importance to the four defined objectives and different priority to the 16 maintenance groups, statistical analyses were conducted with the four sets of values, one for each of the four pilot districts, using Kruskal-Wallis test. At last, a web-based prototype system was developed to assist users in generating the list of maintenance projects under budget constraints. Exposure factors, ADT and truck volume, were applied in the system to factor in the impact of traffic to the maintenance strategy. Users of this system can choose to use the weights and parameter values from one of the pilot districts which they think is most comparable to their own district or the state average values that has been proved to be applicable to all the districts in Texas. / text
158

Automated Pattern Recognition for Intonation (PRInt) : an essay on intonational phonology and categorization / Essay on intonational phonology and categorization

Bacuez, Nicholas 25 February 2013 (has links)
This dissertation provides experimental evidence for the validity of an intonational phonology. The widely used Autosegmental-Metrical theory con- tends that the phonological structure of intonation can be expressed with two tonal targets (L/H tones and derivatives) and retrieved from its phonetic im- plementations. However, it has not been specifically demonstrated so far in a systematic way. This dissertation argues that this view on intonational phonol- ogy considers the phonetic forms of intonation as instances of phonologically structured intonational units forming functionally discrete categories (tones and derivatives). The model of Pattern Recognition for Intonation (PRInt) applies the concepts of categorization (vagueness, prototype, degrees of typicality) to in- tonation in order to abstract the phonological structure of intonational cate- gories from the ranking, by degree of typicality, of their variations in phonetic implementation. First, instances belonging to an intonation category are collected. Sec- ond, a pattern recognition module, relying on the 4-layer structure protocol, extracts a feature vector from the phonetic data of each instance: a sequence of structurally organized tones (L/H tones and derivatives). Third, a fuzzy classifier, using two functions (frequency and similar- ity), organizes the data from the feature vectors of all instances by degree of typicality (grade of membership of values in multisets) and generates the phonological structure of the intonation category, the prototypical pattern, ex- tracted from all instances, and that subsumes them all. It also re-creates the phonetic implementations of the phonological structure but with their features ranked by degree of typicality. This allows the model to distinguish phono- logically distinct structures from phonetic variations of the same phonological structure. The model successfully extracted the phonological intonation structure associated to three modalities of closed questions in French: neutral, doubt- ful, and surprised. It found that neutral and doubtful closed questions are phonologically distinct while surprise is a phonetic allocontour of the neutral modality, in line with prior characterizations of these patterns. It demon- strated that a bi-tonal phonological structure of intonation can be retrieved from phonetic variations. A versatile modeling tool, PRInt will be developed to use its acquired knowledge to evaluate the categorical status of novel instances and to extract multiple phonological units from mixed corpora. / text
159

Controlling a Robot Hand in Simulation and Reality

Birgestam, Magnus January 2008 (has links)
This master thesis was made at the Institute of Technology Stockholm and is a part of a robot hand project called 10-X with the aim to develop a low-cost robot hand that is light and strong. The project specification is to further improve the ability to control the robot hand in a user friendly way. This has been done by implementing a controller, earlier used and developed at KTH, which is intuitive and easy to customize after the needs in different kinds of grasps. To make the controller easy to use an user interface has been made. Before the implementation of the controller was made on the real hand it was tested and development on a simulation created in MATLAB/simulink with help from a graphic physics engine called GraspIt! The movement of the robot finger is effected of the force from a leaf spring and a tendon that bends the finger. Also the finger is exposed of contact forces and all these components had to be modeled in the simulation to make the finger act properly. / Detta examensarbete är genomfört på KTH Stockholm och är en del av ett projekt, kallat 10-X, vars syfte är att utveckla och ta fram en robothand som är lätt och stark samtidigt som den är billig. Projektets målsättning är att vidare förbättra och utveckla möjligheten att kontrollera robothanden på ett användarvänligt sätt. Detta har gjorts genom att implementera en regulator, tidigare utvecklad och använd på KTH, som är instruktiv och lätt att anpassa efter olika typer av grepp. För att göra regulatorn enkel att använda har ett användargränssnitt skapats. Innan regulatorn implementerades på den riktiga robothanden utvecklades och testades den på en simuleringsmodell, skapad i MATLAB/simulink med hjälp av en grafisk fysikmotor GraspIt! Rörelsen hos ett robotfinger påverkas av krafter från en bladfjäder och den lina som böjer fingret. Fingret utsätts också för kontaktkrafter och alla dessa komponenter blev modellerade i simulatorn för att få fingret att bete sig korrekt.
160

Finansų maklerio įmonės veiklos automatizavimo sistemos prototipas / Automatization system prototype of Finance Macler Company

Noreikaitė, Kristina 10 January 2005 (has links)
Automatization system prototype of Finance Macler Company.

Page generated in 0.0447 seconds