• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 1620
  • 548
  • 454
  • 349
  • 171
  • 67
  • 61
  • 59
  • 31
  • 22
  • 21
  • 21
  • 14
  • 11
  • 11
  • Tagged with
  • 4011
  • 612
  • 590
  • 472
  • 431
  • 389
  • 302
  • 293
  • 284
  • 253
  • 245
  • 228
  • 210
  • 206
  • 195
  • 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.
111

3D Shape Reconstruction from Multiple Range Image Views

Ganapathi Annadurai, Kartick January 2006 (has links)
Shape reconstruction of different three dimensional objects using multiple range images has evolved recently within the recent past. In this research shape reconstruction of a three dimensional object using multiple range image views is investigated. Range images were captured using the Waikato Range Imager. This range images camera is novel in that it uses heterodyne imaging and is capable of acquiring range images with precision less than a millimeter simultaneously over a full field. Multiple views of small objects were taken and the FastRBF was explored as a mean of registration and surface rendering. For comparison to the real range data, simulated range data under noise free condition were also generated and reconstructed with the FastRBF tool box. The registration and reconstruction of simple object was performed using different views with the FastRBF toolbox. Analysis of the registration process showed that the translation error produced due to distortion during registration of different views hinders the process of reconstructing a complete surface. While analyzing the shape reconstruction using the FastRBF tool it is also determined that a small change in accuracy values can affect the interpolation drastically. Results of reconstruction of a real 3D object from multiple views are shown.
112

Fast solvers for Toeplitz systems with applications to image restoration

Wen, Youwei. January 2006 (has links)
Thesis (Ph. D.)--University of Hong Kong, 2006. / Title proper from title frame. Also available in printed format.
113

Advances in parallel imaging reconstruction techniques

Qu, Peng, January 2006 (has links)
Thesis (Ph. D.)--University of Hong Kong, 2006. / Title proper from title frame. Also available in printed format.
114

Parametric reconstruction of multidimensional seismic records

Naghizadeh, Mostafa 11 1900 (has links)
Logistic and economic constraints often dictate the spatial sampling of a seismic survey. The process of acquisition records a finite number of spatial samples of the continuous wave field. The latter leads to a regular or irregular distribution of seismograms. Seismic reconstruction methods are used to recover non-acquired data and to synthesize a dense distribution of sources and receivers that mimics a properly sampled survey. This dissertation examines the seismic sampling problem and proposes algorithms for efficient multidimensional seismic data reconstruction. In particular, I address the problem of reconstructing irregularly sampled data using multidimensional linear prediction filters. The methodology entails a strategy that consists of two steps. First, the unaliased part of the wave field is reconstructed via Fourier reconstruction (Minimum Weighted Norm Interpolation). Then, prediction filters for all the frequencies are extracted from the reconstructed low frequencies. The latter permits the the recovery of aliased data with Multi-Step Auto-Regressive (MSAR) algorithm. The recovered prediction filters are used to reconstruct the complete data in either the f-x domain (MSAR-X) or the f-k domain (MSAR-K). The thesis also presents the use of Exponentially Weighted Recursive Least Squares (EWRLS) to estimate adaptive prediction filters for f-x seismic interpolation. Adaptive prediction filters are able to model signals where the dominant wavenumbers are varying in space. This concept leads to a f-x interpolation method that does not require windowing strategies for optimal results. In other words, adaptive prediction filters can be used to interpolate waveforms with spatially variant dips. / Geophysics
115

Intramural Stress and Inflammation in Arterial Branches: A Histology-Based Approach

Carnell, Peter Hamilton 22 September 2004 (has links)
Hypertension is a major risk factor for coronary artery disease, stroke, and kidney disease. Many studies suggest that elevated intramural stresses caused by hypertension may stimulate inflammatory changes, but little has been done to ascertain whether inflammation and stress are spatially correlated. Such correlations are a first step in identifying the mechanisms that may relate intramural stress to disease so that more effective clinical treatments may be developed. Arterial branches exhibit local stress peaks and are focal points for the onset of disease. They are thus a logical place to examine whether high stresses spatially correlate with increased inflammation. This research seeks to 1) develop a histology-based method to reconstruct small arterial branches; 2) use finite element analysis to evaluate intramural stresses where experimental testing is of limited use; 3) quantify biological measures of inflammation; and 4) visually and statistically compare the distribution of stress with the distribution of inflammation. Hypertension was induced in Sprague-Dawley rats by implanting Angiotensin II pumps for 7 days or 21 days. Normotensive rats were used as controls. To preserve morphology the mesentery was pressure-fixed in situ, harvested, processed, and embedded in glycol methacrylate resin. Branch geometry was reconstituted from serial sections. This involved: correcting deformations caused by sectioning; aligning sections into an image stack; identifying vessel boundaries; creating a surface suitable for finite element analysis; reducing the branch geometry to a midplane surface; and using Ansys (Ansys, Inc.) to mesh the midplane surface with a variable-thickness shell element. The pattern of inflammation was characterized by measuring the local density of monocytes and macrophages. Cell density was expressed as a distribution on the branch surface, which simplified visualization and facilitated statistical comparisons of inflammation with stress. Both intramural stresses and inflammation were greater near branches during hypertension. In most cases, however, high stresses and high cell density were not spatially collocated. The onset of an adaptive response may reduce the strength of this correlation. Maximal wall tension, defined as the maximal midplane stress multiplied by the wall thickness, was elevated near branches and strongly correlated with cell density.
116

A study on Reconstruction Areas Sustainable Development Strategies¢wThe case study of Liouguei

Yang, Chen-Hung 12 September 2012 (has links)
Typhoon, Morakot lashed Taiwan. Many cities had been destroyed. Liouguei was one of disaster areas. Some roads, farms, rivers, industry had been strong damage. Travel industry was a typical case. Traveler numbers severely reduced after event. In order to reconstructed Liouguei. The research adopts sustainable development and Delphi method to study some strategies for Liouguei. The research surveyed sample from specialist s, who was industry personnel or Officials or academics. The research result is ¡§Prohibit overdevelopment Liouguei¡¨, ¡§Hold international activities¡¨, ¡§Training of tourism personnel¡¨. These Strategies are good with development in Liouguei.
117

A Preliminary Reconstruction of the Yassiada Sixteenth-Century Ottoman Wreck

Labbe, Matthew A. 2010 May 1900 (has links)
While excavating a late fourth-century Roman merchantman off the coast of Yassiada, Turkey in 1967, archaeologists discovered another, more recent wreck lying across the stern of the Roman wreck. The artifact assemblage, dendrochronology, and carbon-14 dating indicated that the wreck was of Ottoman origin and dated to the late sixteenth-century. In 1982 and 1983, archaeologists under the auspices of the Institute of Nautical Archaeology at Texas A&M University returned to the site to fully excavate the vessel and raise its timbers for detailed study and conservation at the Bodrum Museum of Underwater Archaeology in Turkey. The purpose of this thesis is to analyze the remains of the hull by building upon previous preliminary reconstruction efforts to determine the ship's intended form and function. To accomplish this task, 1:10 scale drawings of the timbers were used to construct a half breadth model of the ship. By matching the nail holes on the recovered planking to the preserved remains of the ship's framing, it was possible to assess the hull's contours through transfer to a lines drawing. The resulting drawings show a moderately sized vessel with a wide flat bottom. In order to place the reconstruction into perspective, archaeological remains of similar shipwrecks and period iconography were consulted in order to suggest the ship's type and function. Four shipwrecks were found that have similar construction features to those on the Ottoman wreck. Three of the wrecks had the same unusual knuckle joints used in securing futtocks to frames that the Ottoman wreck has, shedding light on design and construction philosophy of ships in the eastern Mediterranean. The preliminary analysis of period iconography in conjunction with the remains of similar shipwrecks indicated that the vessel was a cargo carrier that may have ties to the Ottoman navy. Four types of ships from the same general period, the felluca, polacre, and shebek were found to have similar design features to the Ottoman wreck, but the closest iconographic parallel was the saique, which was a two-masted cargo carrier found in the Black Sea and the west coast of Turkey between the sixteenth and eighteenth centuries.
118

The Kitten Shipwreck: Archaeology and Reconstruction of a Black Sea Merchantman

Batchvarov, Kroum Nickolaev 2009 August 1900 (has links)
In the early 1980s Bulgarian archaeologists of the newly established Centre for Underwater Archaeology at Sozopol discovered the remains of a post-medieval ship in the southern Bay of Kitten, in the lee of Cape Urdoviza. Between 2000 and 2003, the Institute of Nautical Archaeology at Texas A&M University and a team from the Bulgarian Centre for Underwater Archaeology returned to the site to complete the first excavation of a post-medieval shipwreck in the Black Sea. The well-preserved vessel, lost in the reign of the Ottoman Sultan Selim III (1789-1807), featured constructional characteristics seen in Iberian shipbuilding tradition, such as scarfed floors and futtocks and filling pieces between the frames. Analysis of the Kitten ship permitted the author to reconstruct the whole-molding process used by the shipwright to build the vessel. The futtock-floor hook-scarphs appear to be the identifying part of the molding process. Morphologically identical scarfs have also been observed on Mediterranean wrecks such as Culip VI (14th century), Yassiada (16th century) and Sardineax (17th century), which suggests that the Kitten ship is a very late example of a Mediterranean-wide shipbuilding tradition that developed in the Middle Ages and from which the Atlantic vessel descended. It also points that the Black Sea maritime culture was an integral part of Mediterranean seafaring tradition. The dissertation offers an overview of the artifact assemblage raised from the Kitten shipwreck. Fragments of an iconostas prove that at the time of sinking the vessel was operated by Christians. The smoking paraphernalia found on the wreck provides opportunity to correct the dating of some pipe bowl types proposed by previous scholars. Personal belongings open a window into the life of the crew of a Black Sea merchantman. Although the ethnicity of the crew cannot be determined at this time, a group of copper galley ware suggests that they may have been Bulgarian. An unsolved mystery is presented by the presence of a navigational instrument, probably an octant, on board.
119

Tissue-Engineering Bone from Omentum

Kamei, Yuzuru, Toriyama, Kazuhiro, Takada, Toru, Yagi, Shunjiro 08 1900 (has links)
No description available.
120

The Reconstruction Formula of Inverse Nodal Problems and Related Topics

Chen, Ya-ting 12 June 2001 (has links)
Consider the Sturm-Liouville system : 8 > > > > > < > > > > > : − y00 + q(x)y = y y(0) cos + y0(0) sin = 0 y(1) cos + y0(1) sin = 0 , where q 2 L 1 (0, 1) and , 2 [0, £¾). Let 0 < x(n)1 < x(n)2 < ... < x(n)n − 1 < 1 be the nodal points of n-th eigenfunction in (0,1). The inverse nodal problem involves the determination of the parameters (q, , ) in the system by the knowledge of the nodal points . This problem was first proposed and studied by McLaughlin. Hald-McLaughlin gave a reconstruc- tion formula of q(x) when q 2 C 1 . In 1999, Law-Shen-Yang improved a result of X. F. Yang to show that the same formula converges to q pointwisely for a.e. x 2 (0, 1), when q 2 L 1 . We found that there are some mistakes in the proof of the asymptotic formulas for sn and l(n)j in Law-Shen-Yang¡¦s paper. So, in this thesis, we correct the mistakes and prove the reconstruction formula for q 2 L 1 again. Fortunately, the mistakes do not affect this result.Furthermore, we show that this reconstruction formula converges to q in L 1 (0, 1) . Our method is similar to that in the proof of pointwise convergence.

Page generated in 0.1264 seconds