bluuebunny/crossref_metadata_2025_split huggingface dataset:
Frequency‐directivity scanning in laboratory radar imaging
Authors: Bertrand Jacqueline , Bertrand Pierre , Ovarlez Jean‐Philippe 
Published: March 2007

AbstractThis work concerns an extension of usual radar imaging in which the pictures of the target do not simply exhibit the position of elementary reflectors but also give the behavior of these reflectors when the frequency and the direction of illumination vary. Essentially, the technique consists of describing the target by a generalized image which can be computed from the knowledge of the backscattering function on a large domain in the angle‐frequency space. A discussion of the physical relevance of the approach is given and its conclusions are used to derive a practical formulation relying on a special wavelet transform. The implementation of the technique is developed by using the fast Mellin transform. Special features of the method are the use of data in polar format without resampling and the fact that the computation can be easily parallelized.©1994 John Wiley & Sons Inc
Ionospheric tomography algorithms
Authors: Raymund T. D. 
Published: March 2007

AbstractThe relatively recent development of inexpensive, high‐speed computational resources has made computerized tomography a readily accessible tool for remote sensing. A variety of geophysical remote applications have made use of the technique; in particular, tomography has been used to image the electron density in the Earth's ionosphere. As in most cases there are problems unique to the application. A review of the algorithms used to date is presented with a sampling of experimental results.©1994 John Wiley & Sons Inc
Resolution analysis of ionospheric tomography systems
Authors: Na Helen , Sutton Eric 
Published: March 2007

AbstractOne of the most recent applications for tomographic imaging is the measurement of the electron density distribution in the ionosphere. This imaging system is a unique and challenging tomographic system because of the physical constraints of the system and the nature of the electron density distribution. To fully understand the potential and limitations of this imaging system, analysis of the resolving capabilities is needed. This article provides a review of current analysis methods for both system evaluation and characterization of the effects of individual degradation parameters. This article also presents a study of the effect of system configuration on the information content of projections.©1994 John Wiley & Sons Inc
Finite state residual vector quantizer for image coding
Authors: Huang Steve Shih‐Yu , Wang Jia‐Shung 
Published: March 2007

AbstractFinite state vector quantization (FSVQ) has been proven to be a high‐quality and low‐bit rate coding scheme. An FSVQ has achieved the efficiency of a small codebook (the state codebook) VQ while maintaining the quality of a large codebook (the master codebook) VQ. However, the large master codebook becomes a primary limitation of FSVQ when the implementation is carefully taken into account. A large amount of memory would be required in storing the master codebook, and much effort would be spent in maintaining the state codebook if the master codebook became too large. This problem could be partially solved by the mean/residual technique (MRVQ)‐that is, the block means and the residual vectors would be separately coded. However, MRVQ has its own drawbacks. Additional bits would be required in coding those means. Moreover, electing the state codebooks in the residual domain would be difficult. A new hybrid coding scheme called the finite state residual vector quantization (FSRVQ) is proposed in this article for the sake of using both advantage in FSVQ and MRVQ. The codewords in FSRVQ were designed by removing the block means to reduce the codebook size. The block means were predicted by the neighboring blocks to reduce the bit rate. In addition, the predicted means were added to the residual vectors so that the state codebooks could be generated entirely. The performance of FSRVQ was indicated from the experimental results to be better than that of both ordinary FSVQ and MRVQ uniformly.©1994 John Wiley & Sons Inc
Part segmentation from stereo
Authors: Chen Liang‐Hua , Lin Wei‐Chung , Liao Hong‐Yuan Mark 
Published: March 2007

AbstractThis article addresses the problem of segmenting objects into parts using stereo images. There are three components in the part segmentation process: surface segmentation, region grouping, and volumetric models (superquadrics) recovery/segmentation. The surface segmentation process segments the image into a set of regions such that each region represents a smooth surface. The region grouping process merges the segmented regions into parts. Finally the process of volumetric models recovery/segmentation recovers the part model and segments that part into smaller parts if necessary. Because we use both surface and volumetric models to drive the part segmentation process, we can capture more geometric properties of the object, and the application domain of our approach is broader than that of previous approaches. The performance of the proposed system is demonstrated with real images and synthetic images. Experimental results show that the system is stable and capable of handling a variety of objects.©1994 John Wiley & Sons Inc
Stochastic geophysical diffraction tomography
Authors: Tsihrintzis George A. , Devaney Anthony J. 
Published: March 2007

AbstractWe revisit geophysical diffraction tomography (GDT) and cast it into a stochastic framework, in which the geophysical formation to be imaged is modeled as a realization of a two‐dimensional stationary random process. It is shown that the optimum reconstruction algorithm, in both the cases of offset vertical seismic profiling and well‐to‐well probing, attains a modified filtered backpropagation form.©1994 John Wiley & Sons Inc
Architecture and implementation of the grand alliance HDTV video encoder
Authors: Mailhot John N. , Paik Woo H. 
Published: March 2007

AbstractA high‐definition television (HDTV) video compression encoder is being constructed for use during the standardization process for United States terrestrial broadcast HDTV. The encoder generates an MPEG‐2 main profile/high level compliant bitstream at compressed data rates from 10–80 million bits/second. Both interlaced and progressive image formats in image sizes up to 1080 lines × 1920 pixels per line are supported.©1994 John Wiley & Sons Inc
HDTV transmission formats and migration path
Authors: Lim Jae S. , Sunshine Lon E. 
Published: March 2007

AbstractThe current proposal for terrestrial broadcasting of HDTV in the United States incorporates a flexible approach toward encoding and transmission. Specifically, the format used to encode an HDTV picture will not be fixed. Instead, a variety of transmission formats will be available, unlike the current (NTSC) system. Furthermore, although a basic set of formats will exist initially, it is possible that this set can change over time, depending on the evolution of relevant technologies. This article will consider various topics related to the current and future transmission formats associated with HDTV systems in the United States. This article discusses the usefulness of allowing multiple transmission formats and describes the formats which will be immediately available for HDTV broadcasting, as agreed upon by the Grand Alliance. The relationship between source formats, transmission formats, and display formats are discussed, with reference to some of the signal processing modules required to convert between formats. Finally, the migration of HDTV to incorporate additional formats is addressed. This report describes a method of achieving this migration in a backward‐compatible manner, so that the basic HDTV receivers will not become obsolete.©1994 John Wiley & Sons Inc
Optimal image formats for advanced television and the NII
Authors: Demos Gary 
Published: March 2007

AbstractVarious high‐definition television (HDTV) and advanced television (ATV) scanning parameter sets have been proposed, including the “Grand Alliance” proposal before the U.S. Federal Communications Commission. However, the American Society of Cinematographers has recommended that the proposed 16:9 aspect ratio should be replaced by a simpler and more pleasing 2:1 aspect ratio. Various proposed and existing formats of interest include 640 × 480, 864 × 648, 1024 × 768, 1152 × 864, and 1280 × 1024 for computer screens, and widescreen formats at or near 2 megapixels. When these formats are analyzed in the context of forming the basis for a suitable hierarchy of scalable resolutions and temporal rates with this new aspect ratio in mind, some significant patterns emerge. Certain fundamental issues in constructing a convenient hierarchy include progressive scanning (no interlace), square pixels (or simple squeezes), and a simple fractional relationship between members of the hierarchy, both temporally and in resolution. There is also a need to exceed 70 Hz in display rate for the wide, bright screens of HDTV/ATV. There is great value in compatibility with computer displays, which exceed 70 Hz with various common resolutions in today's ubiquitous 4:3 aspect ratio. The development of a national and global information infrastructure (NIL/GII) would benefit greatly from such commonality of computer and HDTV/ATV formats. There will be a need for every display to present the richest possible image quality in support of the presentation of text, graphics, and still images, as well as our national and world hertage of high‐resolution films. It will also be necessary to develop guidelines for the composition of images and text by taking into account the common display formats which will be available. This is done by understanding the common “safe area” throughout the variety of existing and future displays, and by considering legibility on each. The best possible architecture for digital HDTV/ATV for the United States and internationally will be needed to support the major NII/GII applications, including health care, library access, education, collaborative and remote work, interactive news, on‐line commerce, and many other uses in addition to entertainment..©1994 John Wiley & Sons Inc
Imaging in three‐dimensional conformal radiation therapy
Authors: Mohan Radhe , Rothenberg Lawrence , Reinstien Lawrence , Ling C. Clifton 
Published: March 2007

AbstractBy and large, radiation therapy is a noninvasive method of the treatment of cancer requiring knowledge of the precise location and extent of the disease to be destroyed and the organs to be protected from radiation damage. Images have always played a central role in providing the requisite information for this mode of cancer treatment. Different types of images, such as computed tomography (CT); magnetic resonance imaging (MRI), positron emission tomographic (PET), simulator, etc., are used to varying degrees depending upon their relevance to radiation oncology as well as their accessibility. It is often necessary to merge data from various types of images. The availability of three‐dimensional information from tomographic images has allowed the introduction of three‐dimensional conformal radiation therapy (3DCRT) methods. Images are employed for diagnosing and establishing the extent of the disease, planning and delivery treatments, and evaluating the effectiveness of the treatment in controlling the disease and assessing the damage to normal tissues. Each image type has a unique informational content of importance to radiation oncology. To extract the maximum information from images, it is necessary to employ various image processing tools. These tools allow us to perform such functions as (1) image enhancement; (2) image correlation to register information from various images; (3) segmentation of images to extract the surface outlines of the tumor volume and normal anatomic structures; and (4) two‐ and three dimensional data visualization. One important aspect of planning radiation treatments is the computation of dose distribution in the patient for a proposed configuration of radiation beams. This step requires tracing rays in a three‐dimensional CT image data set to compute radiologic path lengths through the patient's body. Although images are employed to a great advantage in radiation oncology, many problems still remain to be solved. Of the various 3DCRT tasks, the outlining of contours of the volume of intended treatment and normal anatomy on images is highly labor‐intensive and fraught with uncertainty. In addition, the integration of data from various imaging modalities is difficult and error prone because of distortions inherent in imaging and also because of the motion, deformation, and displacement of patients and their internal anatomy. Investigations are in progress to find solutions to these problems.
Tomotherapy: Optimized planning and delivery of radiation therapy
Authors: Mackie T. Rockwell , Holmes Timothy W. , Reckwerdt Paul J. , Yang James 
Published: March 2007

AbstractIn contemporary radiotherapy dose optimization, radiation beams and beam modifiers are iteratively selected until the dose distribution is acceptable. Another approach, referred to as the “inverse problem,” is: Given the dose prescription, compute the optimal set of photon beams while preventing unphysical solutions such as negative beam weights, and iterate to achieve the prescription as closely as possible. This solution to this inverse problem, which uses image reconstruction mathematics, entails the delivery of large numbers of nonuniform beam intensities to produce uniform dose distributions. These dose distributions can be arranged to conform very closely to even complex target volumes, yet spare surrounding sensitive tissue. Alternatively, the dose distributions can be arranged to generously treat a regional field and “conformally avoid” overtreating sensitive volumes within the field. Multiple dose prescriptions can be delivered without additional effort. We propose that a practical way of delivering optimized dose distributions would be to intensity modulate a photon beam, using collimator leaves intersecting a slit field of radiation. Modulation is achieved by varying the time that the leaves are blocking the field. A practical geometry to deliver such a beam is a computed tomography‐like gantry configuration, which also lends itself to tomographic setup verification of dose delivered to the patient. We refer to such a delivery method as “tomotherapy.” Several types of tomotherapy simulations have been conducted. A fully three dimensional optimized treatment planning system using iterative filtered back‐projection have been developed. We will present examples of conformal plans for breast and prostate radiotherapy. We have constructed an experimental apparatus for simulating helical tomotherapy delivery by simultaneously rotating and longitudinally translating a phantom past an intensity‐modulated fan beam. A comparison between a computation and and experimentally realized plan is presented. A Monte Carlo simulation of the angular distribution and energy fluence spectrum of 10‐MV photons produced by a tungsten target have been used to estimate the optimized shape and mass of a primary shielding required to meet regulatory standards.
The exponential radon transform and projection filtering in radiotherapy planning
Authors: Bortfeld Thomas R. , Boyer Arthur L. 
Published: March 2007

AbstractThe mathematical problem of generating a desired dose distribution in a patient who has to undergo external beam radiotherapy is closely related to the problem of reconstructing an image from its projections. Under some simplifying assumptions the theory of the exponential Radon transform as developed for SPECT image reconstruction can be successfully applied to the field of radiotherapy. This results in a projection‐filtering algorithm for the calculation of optimal beam profiles. The method yields analytical solutions for circular and triangular dose distributions, and combinations thereof. Practical solutions for arbitrary cases can be found numerically. The problem of unphysical negative values in the calculated beam profiles is solved by a method combining “cutting off” and “shifting”.
A general optimization procedure for stereotactic small‐beam multi‐isocentric radiotherapy
Authors: Lefkopoulos D. , Levrier M. , Bendada S. , Touboul E. 
Published: March 2007

AbstractClinical experience in single‐dose stereotactic radiotherapy of irregular complex lesions has shown that new developments in optimization procedures were necessary to improve dose distribution, making this conformal technique more efficient. We propose a conformal procedure for stereotactic radiotherapy of complex lesions treated with multiple isocenters based on the associated targets methodology. The successive steps of this conformal procedure are: (a) the determination of the number of subvolumes; (b) the choice of collimator diameters using a dosimetric data basis; (c) the search by the inverse SVD optimizer algorithm for the optimal irradiation space and the minibeam weights for each subvolume using singular value decomposition; (d) the basis of quantitative evaluation criteria for the choice of satisfactory solutions on dose‐volume histograms and clinical considerations. The efficiency of the SVD optimizer to planify multi‐isocentric treatments was examined in the case of an irregular lesion planified with two isocenters. The condition number of this dual isocentric configuration showed a more ill‐conditioned problem than in the monoisocentric case. Examining different reconstructed weighting vectors, we observed that optimal solutions are obtained with the first singular components and an important healthy tissue overdosage occurs when the number of singular components used in the SVD expansion increases. Our SVD optimization approach is a general procedure which can be applied to different radiotherapy techniques.
Bayesian image restoration in astronomy: Application to images of the recent collision of comet shoemaker‐levy 9 with jupiter
Authors: Molina R. , Mateos J. , Abad J. , De La Blanca N. PÉRez , Molina A. , Moreno F. 
Published: March 2007

AbstractIn this work, we examine simple to complex methods proposed within the Bayesian paradigm to perform image restoration in astronomy. We start by describing the classical conditional and simultaneous autoregressions, then we move on to study how to incorporate smoothness constraints to the classical Richardson‐Lucy restoration method and also how to modify the image scale and define prior models on other scales than the linear one. Finally, we compare those models on images of Jupiter after the impacts of the fragments of the comet Shoemaker‐Levy 9 at two wavelengths.
Palmitic acid substitution on cationic polymers for effective delivery of plasmid DNA to bone marrow stromal cells
Authors: Incani Vanessa , Tunis Emily , Clements Basak Acan , Olson Cori , Kucharski Cezary , Lavasanifar Afsaneh , Uludag Hasan 
Published: March 2007

AbstractNonviral gene carriers are actively explored in gene therapy due to safety concerns of the viral carriers. To design effective gene carriers for modification of bone marrow stromal cells (BMSC), an important cell phenotype for clinical application of gene therapy, cationic polymers polyethyleneimine (PEI), and poly‐L‐Lysine (PLL) were substituted with palmitic acid (PA) via amide linkages. Depending on the reaction conditions, PEI and PLL was substituted with 2.2–5.2 and 13.4–16.2 PA per polymer chain. The PA substituted polymers displayed slightly lower binding efficiency towards a plasmid containing Enhanced Green Fluorescent Protein (pEGFP) in an agarose gel binding assay. The cell binding of PLL‐PA, but not PEI‐PA, was particularly enhanced, resulting in higher percentage of the cells displaying a significant polymer uptake. pEGFP delivery into the BMSC was also significantly increased with the PLL‐PA (vs. PLL), but not PEI‐PA (vs. PEI). The transfection efficiency of PLL‐PA was significantly higher (∼fivefold) than the unmodified polymer. We conclude that PA substitution on PLL provides an effective carrier for transfection of primary cells derived from the bone marrow. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2007.
Identification of a monopartite sequence in PU.1 essential for nuclear import, DNA‐binding and transcription of myeloid‐specific genes
Authors: Kwok Juliana C. , Perdomo José , Chong Beng H. 
Published: March 2007

AbstractThe Ets transcription factor PU.1 is an essential regulator of normal hematopoiesis, especially within the myeloid lineage. As such, endogenous PU.1 predominantly localizes to the nucleus of mammalian cells to facilitate gene regulation. However, to date, little is known regarding the mechanisms of PU.1 nuclear transport. We found, using HeLa and RAW 264.7 macrophage cells, that PU.1 enters the nucleus via passive diffusion and active transport. The latter can be facilitated by: (i) the classical pathway requiring importin α and β; (ii) the non‐classical pathway requiring only importin β; or (iii) direct interaction with nucleoporins. A group of six positively charged lysine or arginine residues within the Ets DNA‐binding domain was determined to be crucial in active nuclear import. These residues directly interact with importin β to facilitate a predominantly non‐classical import pathway. Furthermore, luciferase reporter assays demonstrated that these same six amino acids are crucial for PU.1‐mediated transcriptional activation of myeloid‐specific genes. Indeed, these residues may represent a consensus sequence vital for nuclear import, DNA‐binding and transcriptional activity of Ets family members. By identifying and characterizing the mechanisms of PU.1 nuclear import and the specific amino acids involved, this report may provide insights into the molecular basis of diseases. J. Cell. Biochem. 101: 1456–1474, 2007. © 2007 Wiley‐Liss, Inc.
Homogeneous enzyme immunoassay for macromolecular antigens using avidin biotin enzyme
Authors: Ashihara Yoshihiro , Nishizono Isao , Miyagawa Eiich , Kasahara Yasushi 
Published: March 2007

AbstractA unique homogeneous enzyme immunoassay used for the determination of haptens and macromolecular antigens has been developed. It consists of avidin–antigen conjugate, anti‐ligand antibody, and biotin enzyme (propionyl‐CoA carboxylase). The immunological reaction of the conjugate with antibodies specific to ligand sterically prevents enzyme inactivation by avidin. Goat IgG and theophylline were used as model antigens. Avidin–theophylline conjugate inhibited 100% of enzyme activity. Avidin goat IgG conjugate inhibited 90% of enzyme activity.In this method, the measurable range of theophylline was from 500 ng/ml to 50 μg/ml, and for goat IgG, it was 1–1000 μg/ml.
Hela marker chromosomes in human breast tumors: Proposal about the origin of the hela cell line
Authors: Krizman David B. , Carpenter Nancy J. , Pathak Sen , Olivé Matilde , Cailleau Relda , Hsu T. C. 
Published: March 2007

AbstractPrevious cytogenetic studies have shown that marker chromosomes thought to be unique to the human carcinoma cell line HeLa exist in some human breast tumors, but these studies have not found such markers in human cervical carcinoma lines. The present investigation presents cytogenetic data on 10 breast carcinoma and adenocarcinoma samples taken from fresh solid tumors, pleural effusions, and cell lines established from pleural aspirates. G‐banding analysis showed that 10 of the 19 breast tumor samples studied exhibited one or more HeLa markers. The data have led us to believe that HeLa marker chromosomes are characteristic for human breast adenocarcinomas and infiltrating ductal carcinomas and that the origin of the HeLa line could have been a breast tumor metastatic to the cervix.