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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.
61

Determining Inclinations of Active Galactic Nuclei via their Narrow-Line Region Kinematics

Fischer, Travis C 07 August 2012 (has links)
Active Galactic Nuclei (AGN) are axisymmetric systems to first order; their observed properties are likely strong functions of inclination with respect to our line of sight. However, except for a few special cases, the specific inclinations of individual AGN are unknown. We have developed a promising technique for determining the inclinations of nearby AGN by mapping the kinematics of their narrow-line regions (NLRs), which are easily resolved with Hubble Space Telescope (HST) [O III] imaging and long-slit spectra from the Space Telescope Imaging Spectrograph (STIS). Our studies indicate that NLR kinematics dominated by radial outflow can be fit with simple biconical outflow models that can be used to determine the inclination of the bicone axis, and hence the obscuring torus, with respect to our line of sight. We present NLR analysis of 52 Seyfert galaxies and resultant inclinations from models of 17 individual AGN with clear signatures of biconical outflow. From these AGN, we can for the first time assess the effect of inclination on other observable properties in radio-quiet AGN, including the discovery of a distinct correlation between AGN inclination and X-ray column density.
62

Pose estimation of a VTOL UAV using IMU, Camera and GPS / Position- och orienteringsskattning av en VTOL UAV med IMU, Kamera och GPS

Bodesund, Fredrik January 2010 (has links)
When an autonomous vehicle has a mission to perform, it is of high importance that the robot has good knowledge about its position. Without good knowledge of the position, it will not be able to navigate properly and the data that it gathers, which could be of importance for the mission, might not be usable. A helicopter could for example be used to collect laser data from the terrain beneath it, which could be used to produce a 3D map of the terrain. If the knowledge about the position and orientation of the helicopter is poor then the collected laser data will be useless since it is unknown what the laser actually measures. A successful solution to position and orientation (pose) estimation of an autonomous helicopter, using an inertial measurement unit (IMU), a camera and a GPS, is proposed in this thesis. The problem is to estimate the unknown pose using sensors that measure different physical attributes and give readings containing noise. An extended Kalman filter solution to the simultaneous localisation and mapping (SLAM) is used to fuse data from the different sensors and estimate the pose of the robot. The scale invariant feature transform (SIFT) is used for feature extraction and the unified inverse depth parametrisation (UIDP) model is used to parametrise the landmarks. The orientation of the robot is described by quaternions. To be able to evaluate the performance of the filter an ABB industrial robot has been used as reference. The pose of the end tool of the robot is known with high accuracy and gives a good ground truth so that the estimations can be evaluated. The results shows that the algorithm performs well and that the pose is estimated with good accuracy. / När en autonom farkost skall utföra ett uppdrag är det av högsta vikt att den har god kännedom av sin position. Utan detta kommer den inte att kunna navigera och den data som den samlar in, relevant för uppdraget, kan vara oanvändbar. Till exempel skulle en helikopter kunna användas för att samla in laser data av terrängen under den, för att skapa en 3D karta av terrängen. Om kännedomen av helikopterns position och orientering är dålig kommer de insamlade lasermätningarna att vara oanvändbara eftersom det inte är känt vad lasern faktiskt mäter. I detta examensarbete presenteras en väl fungerande lösning för position och orienterings estimering av autonom helikopter med hjälp av en inertial measurement unit (IMU), en kamera och GPS. Problemet är att skatta positionen och orienteringen med hjälp av sensorer som mäter olika fysiska storheter och vars mätningar innehåller brus. En extended Kalman filter (EKF) lösning för simultaneous localisation and mapping (SLAM) problemet används för att fusionera data från de olika sensorerna och estimera positionen och orienteringen. För feature extrahering används scale invariant feature transform (SIFT) och för att parametrisera landmärken används unified inverse depth parametrisation (UIDP). Orienteringen av roboten beskrivs med hjälp av qvartinjoner. För att evaluera skattningarna har en ABB robot används som referens vid datainsamling. Då roboten har god kännedom om position och orientering av sitt främre verktyg gör detta att prestandan i filtret kan undersökas. Resultaten visar att algorithmen fungerar bra och att skattningar har hög noggrannhet.
63

Design of low-cost multi-thread unified shader architecture

Sun, Ya-hsien 14 February 2011 (has links)
In order to increase the data-path utilization of the programmable graphics processor units (GPU) which often stall by waiting for the execution results of those long-latency instructions, multi-thread technique is very often used in the design of GPU. This thesis proposes a multi-thread single unified core GPU design which owns several key features. First, its processor core can execute not only the vertex and fragment shading programs, but also the software rasteriation module which is mostly implemented by a individual hardware module in other GPU designs. Next, the thread-switching policy in our design is based on the non-preempt blocked scheduling. Normally, whether an instruction will be stalled cannot be detected until it enters the instruction-decode stage. In order to achieve zero-penalty thread switching, a single assistant bit will be padded to each instruction in a thread to tell if the next instruction in the same thread will be stalled or not. This mechanism can help achieve a speed-up of 1.4 in some benchmarks used in this thesis. The register file used in GPU processor is usually equipped with up to four access ports, such that it will occupy a significant portion of the entire GPU especially for muti-thread designs where the register set has to be duplicated by several copies. The implementation cost of the register file can be reduced by decreasing its access port number to two based on the proposed multi-bank approach in this thesis. Our experimental results show that this approach can help reduce the overall gate count by 26.12%. Finally, the rest of fixed-pipeline fragment operation is realized by an iterative time-sharing architecture in order to further save the silicon area. The overall gate count of the proposed GPU is 600K.
64

The Executive-Legislature Relations under the Divided Government¢wthe Case Study of Kaohsiung County(1985-2001)

Hung, Chen-Lin 23 September 2003 (has links)
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65

A methodology for component-based user interface modeling with UML

Cheng, Chih-Hsiung 12 July 2004 (has links)
User interface (UI) has become the key element of modern information systems (ISs) and is commonly viewed as one of the decisive factors for the success of an IS project. Many component-based development tools have been introduced by software vendors to meet the needs of designing a variety of UIs. Such modern design tools offer system developer vehicles to create sophisticated UIs with a few codes. However, the modeling methodology from the stages of user requirement modeling to UI modeling based on the modern design tools is virtually lacking. This study presents an integrated modeling methodology, which integrates the unified modeling language with interface drawing and interface glossary to provide a seamless and graphical approach and specifications for component-based UI modeling from user requirement modeling. A real-world case using the integrated approach is presented and a prototype system is developed to illustrate the concepts, application, and the advantages of using the proposed methodology.
66

¢Û¢Ò¢Ï¡GTransformation from Class Diagram to User Interface

Chien, Juei-Lung 30 June 2005 (has links)
Modeling software with unified modeling language (UML) and model driven architechutre (MDA) concept have become the new paradigm of modern systems analysis and design. Several CASE tools have been introduced to facilitate the transformation from platform independent model (i.e., class diagram) to platform specific model, and thereby enhance the efficiency of system development. This research presents a systematic methodology which integrated the UML and MDA concept with CASE tool to transform the class diagram into web-based user interface during the system development process. A real-world case using the integrated techniques is presented and the Rational Rose is used to illustrate the concepts, application, and the advantages of using the proposed methodology. With this approach, the system developer can transform class diagram into web-based user interface automatically and thereby enhance the efficiency of system development.
67

Modeling Software with UML¡ÐA Case Study of Personnel Leave System

Chang, Jei-Chen 23 July 2007 (has links)
Modeling software with the model driven architecture (MDA) concept and unified modeling language (UML) has become a new trend for the objected-oriented systems analysis and design. Several CASE tools which embed MDA concept and UML have been introduced to facilitate the transformation from platform independent model (PIM, i.e., class diagram) to platform specific model (PSM) in order to enhance the efficiency of software development. In this work, we present a systematic methodology which integrates the concept of MDA and UML with CASE tool to refine the process of UML transformation. A personnel leave prototype system is implemented to illustrate the concepts, application, and advantages of the proposed methodology. With this approach, software developers can construct the PIM efficiently and thereby enhance the efficiency of system development.
68

The modeling of arsenic removal from contaminated water using coagulation and sorption

Kim, Jin-Wook 01 November 2005 (has links)
To achieve predictive capability for complex environmental systems with coagulation and arsenic sorption, a unified improved coagulation model coupled with arsenic sorption was developed. A unified coagulation model coupled with arsenic sorption was achieved by the following steps: (1) an improved discretized population balance equation (PBE) was developed to obtain the exact solution of conventional coagulation, (2) the improved PBE was extended to an adjustable geometric size interval having higher numerical stability, accuracy, and computational efficiency than existing models for fractal aggregate coagulation that includes agglomeration and fragmentation, (3) a surface complexation equilibrium model and a sorption kinetic model was introduced to predict arsenic sorption behavior onto hydrous metal oxide surfaces, and (4) an improved discretized PBE was coupled with arsenic sorption kinetics and equilibrium models by aid of collision efficiency ?? depending on surface charge (potential) on the hydrous metal oxide particles, colliding particle size ratio, and fluid strain-rate in applied flow system. The collision efficiency ?? into the improved (r,r)ij(r,r)ijdiscretized coagulation model for fractal aggregate yielded a unified improved coagulation model coupled with arsenic sorption kinetics and the equilibrium model. Thus, an improved unified coagulation model could provide high statistical accuracy, numerical stability, and computational efficiency to enhance predictive capability for behavior of arsenic sorption and fractal colloid particle aggregation and break-up, simultaneously. From the investigation, it is anticipated that the unified coagulation model coupled with arsenic sorption kinetics and equilibrium will provide a more complete understanding of the arsenic removal mechanism and its application to water/wastewater treatment. Further, this coupled model can be applied to other water and wastewater treatment systems combined with sorption and filtration processes. These combined processes can be optimized by the coupled model that was developed in this study. By simulating the arsenic sorption and particle size distribution as a pretreatment before filtration (sand filtration or membrane filtration), the overall arsenic removal efficiency and operation cost can be estimated.
69

Aspects of grand unified and string phenomenology

Walker, Joel Wesley 01 November 2005 (has links)
Explored in this report is the essential interconnectedness of Grand Unified and String Theoretic Phenomenology. In order to extract a modeled connection to low-energy physics from the context of superstring theory, it is presently necessary to input some preferred region of parameter space in which to search. This need may be well filled by a parallel study of Grand Unification, which is by contrast in immediate proximity to a wealth of experimental data. The favored GUT so isolated may then reasonably transfer this phenomenological correlation to a string embedding, receiving back by way of trade a greater sense of primary motivation, and potentially enhanced predictability for parameters taken as input in a particle physics context. The Flipped SU(5) GUT will be our preferred framework in which to operate and first receives an extended study in a non-string derived setting. Of particularly timely interest are predictions for super-particle mass ranges and the interrelated question of proton decay lifetime. Corrections to such a picture under the lift to a string embedding are also considered. Two principal approaches to string model building are next treated in turn: the Heterotic Free Fermionic construction and Intersecting D-branes in Orientifold compactifications. In both contexts, a summary of existing constructions, extensions to known procedures, and original phenomenological contributions are described.
70

Improving Business Logic Expression with OCL and CASE Tool

Chen, Sheng-hsien 16 July 2008 (has links)
Traditionally software testing is performed at the coding stage and is costly. Prior research indicated that if the errors can be found prior to the coding stage, the cost for fixing the errors can be reduced. Today, Unified Modeling Language (UML) has become a standard modeling language in object-oriented systems analysis and design. Over the past few years a considerable effort has been made in synthesizing UML, MDA (Model-Driven Architecture), and CASE tool to increase the productivity of the system development. Specifying the business logic constraints with Object Constraint Language (OCL) has become a main trend in this area. This study presents a methodology to specify the business logic constraint with OCL on the platform independent model during the systems analysis and design stage, then transform the OCL expressions into the code model and do the model testing simultaneously with a CASE tool. Three real-world cases and a CASE tool are used to test the usability (including the concepts, application, and advantages) of the proposed methodology. With this approach, software bugs related to business logic constraints can be found at the systems analysis and design stage and thereby reduce the cost of software testing and enhance the efficiency of system development.

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