bluuebunny/crossref_metadata_2025 huggingface dataset:
The Effects of Air Preheat and Number of Orifices on Flow and
Emissions in an RQL Mixing Section
Authors: Holdeman James D. , Chang Clarence T.
Published: November 2007

This study was motivated by a goal to understand the mixing and emissions in the rich-burn/quick-mix/lean-burn combustor scheme that has been proposed to minimize the formation of oxides of nitrogen (NOx) in gas turbine combustors. The study reported in this paper was a reacting jet-in-crossflow experiment at atmospheric pressure in a cylindrical duct. The jets were injected from the perimeter of the duct through round-hole orifices into a fuel-rich mainstream flow. The number of orifices investigated in this study gave over- to optimum to underpenetrating jets at a jet-to-mainstream momentum-flux ratio of 57. The size of individual orifices was decreased as their number increased to maintain a constant total area. The jet-to-mainstream mass-flow ratio was held constant at 2.5. The experiments focused on the effects of the number of orifices and inlet air preheat and were conducted in a facility that provided the capability for independent variation of jet and main inlet air preheat temperature. The number of orifices was found to have a significant effect on mixing and the distributions of species, but very little effect on overall NOx emissions, suggesting that an aerodynamically optimum mixer may not minimize NOx emissions. Air preheat was found to have very little effect on mixing and the distributions of major species, but preheat did increase NOx emissions significantly. Although the air jets injected in the quick-mix section of a RQL combustor may comprise over 70% of the total air flow, the overall NOx emission levels were found to be more sensitive to mainstream air preheat than to jet stream air preheat.
A rigidity penalty term for nonrigid registration
Authors: Staring Marius , Klein Stefan , Pluim Josien P. W.
Published: November 2007

Medical images that are to be registered for clinical application often contain both structures that deform and ones that remain rigid. Nonrigid registration algorithms that do not model properties of different tissue types may result in deformations of rigid structures. In this article a local rigidity penalty term is proposed which is included in the registration function in order to penalize the deformation of rigid objects. This term can be used for any representation of the deformation field capable of modelling locally rigid transformations. By using a B‐spline representation of the deformation field, a fast algorithm can be devised. The proposed method is compared with an unconstrained nonrigid registration algorithm. It is evaluated on clinical three‐dimensional CT follow‐up data of the thorax and on two‐dimensional DSA image sequences. The results show that nonrigid registration using the proposed rigidity penalty term is capable of nonrigidly aligning images, while keeping user‐defined structures locally rigid.
Fast prostate segmentation in 3D TRUS images based on continuity constraint using an autoregressive model
Authors: Ding Mingyue , Chiu Bernard , Gyacskov Igor , Yuan Xiaping , Drangova Maria , Downey Dònal B. , Fenster Aaron
Published: November 2007

In this article a new slice‐based 3D prostate segmentation method based on a continuity constraint, implemented as an autoregressive (AR) model is described. In order to decrease the propagated segmentation error produced by the slice‐based 3D segmentation method, a continuity constraint was imposed in the prostate segmentation algorithm. A 3D ultrasound image was segmented using the slice‐based segmentation method. Then, a cross‐sectional profile of the resulting contours was obtained by intersecting the 2D segmented contours with a coronal plane passing through the midpoint of the manually identified rotational axis, which is considered to be the approximate center of the prostate. On the coronal cross‐sectional plane, these intersections form a set of radial lines directed from the center of the prostate. The lengths of these radial lines were smoothed using an AR model. Slice‐based 3D segmentations were performed in the clockwise and in the anticlockwise directions, where clockwise and anticlockwise are defined with respect to the propagation directions on the coronal view. This resulted in two different segmentations for each 2D slice. For each pair of unmatched segments, in which the distance between the contour generated clockwise and that generated anticlockwise was greater than , a method was used to select the optimal contour. Experiments performed using 3D prostate ultrasound images of nine patients demonstrated that the proposed method produced accurate 3D prostate boundaries without manual editing. The average distance between the proposed method and manual segmentation was . The average intraobserver coefficient of variation (i.e., the standard deviation divided by the average volume) of the boundaries segmented by the proposed method was 1.6%. The average segmentation time of a image on a Pentium IV PC was .
Initial beam size study for passive scatter proton therapy. I. Monte Carlo verification
Authors: Polf Jerimy C. , Harvey Mark C. , Titt Uwe , Newhauser Wayne D. , Smith Alfred R.
Published: November 2007

The purpose of this work was to provide an initial validation of a Monte Carlo (MC) model of the passive scattering treatment nozzle at the University of Texas M. D. Anderson Cancer Center Proton Therapy Center. The MC model included a detailed definition of each beam‐modifying element in the nozzle, and calculations accounted for interactions of the beam with the rotating modulator wheel used to create the spread out Bragg peak. In this work we show comparisons of calculated dose and fluence profiles with measured data from the nozzle for the 250 and beam energies used for patient treatments. Agreement to within of measured data was observed for all MC calculations. The high level of agreement between the measurements and the MC model for the two beam energies studied provides validation for use of the model in a study of the dosimetric effects of the proton beam size and shape at the nozzle entrance.
Soft‐tissue detectability in cone‐beam CT: Evaluation by 2AFC tests in relation to physical performance metrics
Authors: Tward D. J. , Siewerdsen J. H. , Daly M. J. , Richard S. , Moseley D. J. , Jaffray D. A. , Paul N. S.
Published: November 2007

Soft‐tissue detectability in cone‐beam computed tomography (CBCT) was evaluated via two‐alternative forced‐choice (2AFC) tests. Investigations included the dependence of detectability on radiation dose, the influence of the asymmetric three‐dimensional (3D) noise‐power spectrum (NPS) in axial and sagittal or coronal planes, and the effect of prior knowledge on detectability. Custom‐built phantoms ( diameter cylinders) containing soft‐tissue‐simulating spheres of variable contrast and diameter were imaged on an experimental CBCT bench. The proportion of correct responses in 2AFC tests was analyzed as a figure of merit, ideally equal to the area under the receiver operating characteristic curve. was evaluated as a function of the sphere diameter , contrast , dose , plane of visualization (axial/sagittal), apodization filter (Hanning and Ram‐Lak), and prior knowledge provided to the observer [ranging from stimulus known exactly (SKE) to stimulus unknown (SUK)]. Detectability limits were characterized in terms of the dose required to achieve a given level of (e.g., 70%). For example, a stimulus of diameter down to was detected with 70% at dose . Detectability tended to be greater in axial than in sagittal planes, an effect amplified by sharper apodization filters in a manner consistent with 3D NPS asymmetry. Prior knowledge had a marked influence on detectability—e.g., for a sphere was under SUK conditions, compared to for SKE conditions. Human observer tests suggest practical implications for implementation of CBCT: (i) Detectability limits help to define minimum‐dose imaging techniques for specific imaging tasks; (ii) detectability of a given structure can vary between axial and sagittal/coronal planes, owing to the spatial‐frequency content of the 3D NPS in relation to the imaging task; and (iii) performance under SKE conditions (e.g., image guidance tasks in which lesion characteristics are known) is maintained at a lower dose than in SUK conditions (e.g., diagnostic tasks in which lesion characteristics are unknown).
Effects of residual target motion for image‐tracked spine radiosurgery
Authors: Chuang Cynthia , Sahgal Arjun , Lee Letitia , Larson David , Huang Kim , Petti Paula , Verhey Lynn , Ma Lijun
Published: November 2007

A quality assurance method was developed to investigate the effects of residual target motion for hypofractionated spine radiosurgery. The residual target motion (target movement between successive image‐guided corrections) was measured on‐line via dual x‐ray imagers for patients treated with CyberKnife (Accuray, Inc., Sunnyvale, CA), a robotic linear accelerator with intrafractional image‐tracking capability. The six degree‐of‐freedom characteristics of the residual target motion were analyzed, the effects of such motion on patient treatment delivery were investigated by incorporating the probability distribution of the residual motion into the treatment planning dose calculations, and deviations of the doses from those originally planned were calculated. Measurements using a programmable motion phantom were also carried out and compared with the static treatment plan calculations. It was found that the residual target motions were patient specific and typically on the order of . The measured dose distributions incorporating the residual target motion also exhibited discrepancy at the prescription isodose level when compared with the static treatment plan calculations. For certain patients, residual errors introduced significant uncertainties for the dose delivered to the spinal cord, especially at the high dose levels covering a small volume of the spinal cord (e.g., ). In such cases, stringent cord constraints and frequent monitoring of the target position should be implemented.
A dual‐stage method for lesion segmentation on digital mammograms
Authors: Yuan Yading , Giger Maryellen L. , Li Hui , Suzuki Kenji , Sennett Charlene
Published: November 2007

Mass lesion segmentation on mammograms is a challenging task since mass lesions are usually embedded and hidden in varying densities of parenchymal tissue structures. In this article, we present a method for automatic delineation of lesion boundaries on digital mammograms. This method utilizes a geometric active contour model that minimizes an energy function based on the homogeneities inside and outside of the evolving contour. Prior to the application of the active contour model, a radial gradient index (RGI)‐based segmentation method is applied to yield an initial contour closer to the lesion boundary location in a computationally efficient manner. Based on the initial segmentation, an automatic background estimation method is applied to identify the effective circumstance of the lesion, and a dynamic stopping criterion is implemented to terminate the contour evolution when it reaches the lesion boundary. By using a full‐field digital mammography database with 739 images, we quantitatively compare the proposed algorithm with a conventional region‐growing method and an RGI‐based algorithm by use of the area overlap ratio between computer segmentation and manual segmentation by an expert radiologist. At an overlap threshold of 0.4, 85% of the images are correctly segmented with the proposed method, while only 69% and 73% of the images are correctly delineated by our previous developed region‐growing and RGI methods, respectively. This resulting improvement in segmentation is statistically significant.
Monte Carlo study of correction factors for the use of plastic phantoms in clinical electron dosimetry
Authors: Araki Fujio
Published: November 2007

In some recent dosimetry protocols, plastic is allowed as a phantom material for the determination of an absorbed dose to water in electron beams, especially for low energy with beam qualities . In electron dosimetry with plastic, a depth‐scaling factor, , and a chamber‐dependent fluence correction factor, , are needed to convert the dose measured at a water‐equivalent reference depth in plastic to a dose at a reference depth in water. The purpose of this study is to calculate correction factors for the use of plastic phantoms for clinical electron dosimetry using the EGSnrc Monte Carlo code system. RMI‐457 and WE‐211 were investigated as phantom materials. First the values for plastic materials were calculated as a function of a half‐value depth of maximum ionization, , in plastic. The values for RMI‐457 and WE‐211 varied from 0.992 to 1.002 and from 0.971 to 0.979, respectively, in a range of nominal energies from to , and varied slightly as a function of in plastic. Since values depend on the wall correction factor, , of the chamber used, they are evaluated using a pure electron fluence correction factor, , and and for a combination of water or plastic phantoms and plane‐parallel ionization chambers (NACP‐02, Markus and Roos). The and ( and ) values were calculated as a function of the water‐equivalent depth in plastic materials and at a reference depth as a function of in water, respectively. The values varied from 1.024 at to 1.013 at for RMI‐457, and from 1.025 to 1.016 for WE‐211. values for plane‐parallel chambers showed values in the order of 1.5% to 2% larger than unity at , consistent with earlier results. The values of RMI‐457 and WE‐211 were close to unity for all the energy beams. Finally, calculated values of RMI‐457 ranged from 1.009 to 1.005, from 1.010 to 1.003 and from 1.011 to 1.007 for NACP‐02, Markus and Roos chambers, respectively, in the range of to , and the values of WE‐211 were 1.010 to 1.004, 1.010 to 1.004 and 1.012 to 1.008, respectively. The calculated values for the Markus chamber agreed within their combined uncertainty with the measured data.
Dual‐energy approach to contrast‐enhanced mammography using the balanced filter method: Spectral optimization and preliminary phantom measurement
Authors: Saito Masatoshi
Published: November 2007

Dual‐energy contrast agent‐enhanced mammography is a technique of demonstrating breast cancers obscured by a cluttered background resulting from the contrast between soft tissues in the breast. The technique has usually been implemented by exploiting two exposures to different x‐ray tube voltages. In this article, another dual‐energy approach using the balanced filter method without switching the tube voltages is described. For the spectral optimization of dual‐energy mammography using the balanced filters, we applied a theoretical framework reported by Lemacks et al. [Med. Phys. 29, 1739–1751 (2002)] to calculate the signal‐to‐noise ratio (SNR) in an iodinated contrast agent subtraction image. This permits the selection of beam parameters such as tube voltage and balanced filter material, and the optimization of the latter's thickness with respect to some critical quantity—in this case, mean glandular dose. For an imaging system with a thick CsI:Tl scintillator, we predict that the optimal tube voltage would be for a tungsten anode using zirconium, iodine, and neodymium balanced filters. A mean glandular dose of is required to obtain an SNR of 5 in order to detect iodine in the resulting clutter‐free image of a thick breast composed of 50% adipose and 50% glandular tissue. In addition to spectral optimization, we carried out phantom measurements to demonstrate the present dual‐energy approach for obtaining a clutter‐free image, which preferentially shows iodine, of a breast phantom comprising three major components—acrylic spheres, olive oil, and an iodinated contrast agent. The detection of iodine details on the cluttered background originating from the contrast between acrylic spheres and olive oil is analogous to the task of distinguishing contrast agents in a mixture of glandular and adipose tissues.
A Gaussian mixture model for definition of lung tumor volumes in positron emission tomography
Authors: Aristophanous Michalis , Penney Bill C. , Martel Mary K. , Pelizzari Charles A.
Published: November 2007

The increased interest in ‐fluorodeoxyglucose (FDG) positron emission tomography (PET) in radiation treatment planning in the past five years necessitated the independent and accurate segmentation of gross tumor volume (GTV) from FDG‐PET scans. In some studies the radiation oncologist contours the GTV based on a computed tomography scan, while incorporating pertinent data from the PET images. Alternatively, a simple threshold, typically 40% of the maximum intensity, has been employed to differentiate tumor from normal tissue, while other researchers have developed algorithms to aid the PET based GTV definition. None of these methods, however, results in reliable PET tumor segmentation that can be used for more sophisticated treatment plans. For this reason, we developed a Gaussian mixture model (GMM) based segmentation technique on selected PET tumor regions from non‐small cell lung cancer patients. The purpose of this study was to investigate the feasibility of using a GMM‐based tumor volume definition in a robust, reliable and reproducible way. A GMM relies on the idea that any distribution, in our case a distribution of image intensities, can be expressed as a mixture of Gaussian densities representing different classes. According to our implementation, each class belongs to one of three regions in the image; the background (B), the uncertain (U) and the target (T), and from these regions we can obtain the tumor volume. User interaction in the implementation is required, but is limited to the initialization of the model parameters and the selection of an “analysis region” to which the modeling is restricted. The segmentation was developed on three and tested on another four clinical cases to ensure robustness against differences observed in the clinic. It also compared favorably with thresholding at 40% of the maximum intensity and a threshold determination function based on tumor to background image intensities proposed in a recent paper. The parts of the method that are user dependent were evaluated and resulted in initial estimates of the method's precision, which is in the order of of the average tumor volume estimate. With this work we have established the applicability of the GMM‐based segmentation on clinical studies and we have made an initial assessment of the method's precision with respect to tumor volume segmentation.
A method for synchronizing an external respiratory signal with a list‐mode PET acquisition
Authors: Bruyant P. P. , Cheze Le Rest C. , Turzo A. , Jarritt P. , Carson K. , Visvikis D.
Published: November 2007

A method is proposed to synchronize positron emission tomography (PET) list‐mode data with an externally recorded respiratory signal in the absence of a master clock. When the respiratory signal reaches a user‐defined threshold, a trigger mark is stored in the list‐mode file. After the acquisition, synchronization is achieved when the stored trigger marks are superimposed on the respiratory curve to form a horizontal line over time at the user‐defined threshold. Synchronization was possible and unequivocal for ten out of ten clinical studies. The list‐mode acquisition actually started approximately 40 and after acquisition initiation at the user interface of the Philips Gemini and the GE DLS PET‐CT systems, respectively.
Uniform attenuation correction using the frequency‐distance principle
Authors: Zeng Gengsheng L.
Published: November 2007

The frequency‐distance principle (FDP) is a well‐known relationship that relates the distance between the object and the detector to the slope in the two‐dimensional Fourier transform of the projection sinogram. This relationship has been previously applied to compensation of the distance dependent collimator blurring in SPECT (single photon emission computed tomography) in the literature. This paper makes an attempt to use the FDP to correct for uniform attenuation in SPECT. Computer simulations reveal that this technique works well for objects consisting of point sources but does not work well for distributed objects.
Image‐guided high dose rate endorectal brachytherapy
Authors: Devic Slobodan , Vuong Té , Moftah Belal , Evans Michael , Podgorsak Ervin B. , Poon Emily , Verhaegen Frank
Published: November 2007

Fractionated high dose rate endorectal brachytherapy (HDR‐EBT) using CT‐based treatment planning is an alternative method for preoperative down‐sizing and down‐staging of advanced rectal adeno‐carcinomas. The authors present an image guidance procedure that was developed to ensure daily dose reproducibility for the four brachytherapy treatment fractions. Since the applicator might not be placed before each treatment fraction inside the rectal lumen in the same manner as it was placed during the 3D CT volume acquisition used for treatment planning, there is a shift along the catheter axis that may have to be performed. The required shift is determined by comparison of a daily radiograph with the treatment planning digitally‐reconstructed radiograph (DRR). A procedure is developed for DRR reconstruction from the 3D data set used for the treatment planning, and two possible daily longitudinal shifts are illustrated: above and below the planning dose distribution. The authors also describe the procedure for rotational alignment illustrated on a clinical case. Reproduction of the treatment planned dose distribution on a daily basis is crucial for the success of fractionated 3D based brachytherapy treatments. Due to the cylindrical symmetry of the applicator used for preoperative HDR‐EBT, two types of adjustments are necessary: applicator rotation and dwell position shift along the applicator's longitudinal axis. The impact of the longitudinal applicator shift prior to treatment delivery for 62 patients treated in our institution is also assessed.
Optimization of reference library used in content‐based medical image retrieval scheme
Authors: Park Sang Cheol , Sukthankar Rahul , Mummert Lily , Satyanarayanan Mahadev , Zheng Bin
Published: November 2007

Building an optimal image reference library is a critical step in developing the interactive computer‐aided detection and diagnosis (I‐CAD) systems of medical images using content‐based image retrieval (CBIR) schemes. In this study, the authors conducted two experiments to investigate (1) the relationship between I‐CAD performance and size of reference library and (2) a new reference selection strategy to optimize the library and improve I‐CAD performance. The authors assembled a reference library that includes 3153 regions of interest (ROI) depicting either malignant masses (1592) or CAD‐cued false‐positive regions (1561) and an independent testing data set including 200 masses and 200 false‐positive regions. A CBIR scheme using a distance‐weighted ‐nearest neighbor algorithm is applied to retrieve references that are considered similar to the testing sample from the library. The area under receiver operating characteristic curve is used as an index to evaluate the I‐CAD performance. In the first experiment, the authors systematically increased reference library size and tested I‐CAD performance. The result indicates that scheme performance improves initially from to 0.874 and then plateaus when the library size reaches approximately half of its maximum capacity. In the second experiment, based on the hypothesis that a ROI should be removed if it performs poorly compared to a group of similar ROIs in a large and diverse reference library, the authors applied a new strategy to identify “poorly effective” references. By removing 174 identified ROIs from the reference library, I‐CAD performance significantly increases to . The study demonstrates that increasing reference library size and removing poorly effective references can significantly improve I‐CAD performance.
Guiding curve based on the normal breathing as monitored by thermocouple for regular breathing
Authors: Lim Sangwook , Park Sung Ho , Do Ahn Seung , Suh Yelin , Shin Seong Soo , Lee Sang‐wook , Kim Jong Hoon , Choi Eun Kyoung , Yi Byong Yong , Kwon Soo Il , Kim Sookil , Jeung Tae Sig
Published: November 2007

Adapting radiation fields to a moving target requires information continuously on the location of internal target by detecting it directly or indirectly. The aim of this study is to make the breathing regular effectively with minimizing stress to the patient. A system for regulating patient's breath consists of a respiratory monitoring mask (ReMM), a thermocouple module, a screen, inner earphones, and a personal computer. A ReMM with thermocouple was developed previously to measure the patient's respiration. A software was written in LabView 7.0 (National Instruments, TX), which acquires respiration signal and displays its pattern. Two curves are displayed on the screen: One is a curve indicating the patient's current breathing pattern; the other is a guiding curve, which is iterated with one period of the patient's normal breathing curve. The guiding curves were acquired for each volunteer before they breathed with guidance. Ten volunteers participated in this study to evaluate this system. A cycle of the representative guiding curve was acquired by monitoring each volunteer's free breathing with ReMM and was then generated iteratively. The regularity was compared between a free breath curve and a guided breath curve by measuring standard deviations of amplitudes and periods of two groups of breathing. When the breathing was guided, the standard deviation of amplitudes and periods on average were reduced from 0.0029 to 0.00139 (arbitrary units) and from 0.359 s to 0.202 s, respectively. And the correlation coefficients between breathing curves and guiding curves were greater than 0.99 for all volunteers. The regularity was improved statistically when the guiding curve was used.
Sparseness prior based iterative image reconstruction for retrospectively gated cardiac micro‐CT
Authors: Song Jiayu , Liu Qing H. , Johnson G. Allan , Badea Cristian T.
Published: November 2007

Recent advances in murine cardiac studies with three‐dimensional (3D) cone beam micro‐CT used a retrospective gating technique. However, this sampling technique results in a limited number of projections with an irregular angular distribution due to the temporal resolution requirements and radiation dose restrictions. Both angular irregularity and undersampling complicate the reconstruction process, since they cause significant streaking artifacts. This work provides an iterative reconstruction solution to address this particular challenge. A sparseness prior regularized weighted norm optimization is proposed to mitigate streaking artifacts based on the fact that most medical images are compressible. Total variation is implemented in this work as the regularizer for its simplicity. Comparison studies are conducted on a 3D cardiac mouse phantom generated with experimental data. After optimization, the method is applied to in vivo cardiac micro‐CT data.
FEATURE EXTRACTION FOR CLASSIFICATION USING STATISTICAL NETWORKS
Authors: GHOSH ANIL KUMAR , BOSE SMARAJIT
Published: November 2007

In a classification problem, quite often the dimension of the measurement vector is large. Some of these measurements may not be important for separating the classes. Removal of these measurement variables not only reduces the computational cost but also leads to better understanding of class separability. There are some methods in the existing literature for reducing the dimensionality of a classification problem without losing much of the separability information. However, these dimension reduction procedures usually work well for linear classifiers. In the case where competing classes are not linearly separable, one has to look for ideal "features" which could be some transformations of one or more measurements. In this paper, we make an attempt to tackle both, the problems of dimension reduction and feature extraction, by considering a projection pursuit regression model. The single hidden layer perceptron model and some other popular models can be viewed as special cases of this model. An iterative algorithm based on backfitting is proposed to select the features dynamically, and cross-validation method is used to select the ideal number of features. We carry out an extensive simulation study to show the effectiveness of this fully automatic method.
CONTOUR-BASED FEATURE EXTRACTION USING DUAL-TREE COMPLEX WAVELETS
Authors: CHEN G. Y. , XIE W. F.
Published: November 2007

A contour-based feature extraction method is proposed by using the dual-tree complex wavelet transform and the Fourier transform. Features are extracted from the 1D signals r and θ, and hence the processing memory and time are reduced. The approximate shift-invariant property of the dual-tree complex wavelet transform and the Fourier transform guarantee that this method is invariant to translation, rotation and scaling. The method is used to recognize aircrafts from different rotation angles and scaling factors. Experimental results show that it achieves better recognition rates than that which uses only the Fourier features and Granlund's method. Its success is due to the desirable shift invariant property of the dual-tree complex wavelet transform, the translation invariant property of the Fourier spectrum, and our new complete representation of the outer contour of the pattern.
PIXEL-BASED TEXTURE CLASSIFICATION BY INTEGRATION OF MULTIPLE FEATURE EXTRACTION METHODS EVALUATED OVER MULTISIZED WINDOWS
Authors: PUIG DOMENEC , GARCIA MIGUEL ANGEL
Published: November 2007

This paper presents a pixel-based texture classifier oriented to the identification of texture models that can be present in an input image, given a set of models known in advance. The proposed methodology is based on the integration of texture features generated by texture methods that belong to different families, which are evaluated over multiple windows of different sizes. This is a novelty with respect to the current texture classifiers, which are based on specific families of texture methods evaluated over single windows of a size defined empirically. Experiments show that this integration strategy produces better results than classical texture classifiers based on specific families of texture methods.
A COMBINATORIAL APPROACH TO FINGERPRINT BINARIZATION AND MINUTIAE EXTRACTION USING EUCLIDEAN DISTANCE TRANSFORM
Authors: LIANG XUEFENG , BISHNU ARIJIT , ASANO TETSUO
Published: November 2007

Most of the fingerprint matching techniques require extraction of minutiae that are ridge endings or bifurcations of ridge lines in a fingerprint image. Crucial to this step is either detecting ridges from the gray-level image or binarizing the image and then extracting the minutiae. In this work, we firstly exploit the property of almost equal width of ridges and valleys for binarization. Computing the width of arbitrary shapes is a nontrivial task. So, we estimate the width using Euclidean distance transform (EDT) and provide a near-linear time algorithm for binarization. Secondly, instead of using thinned binary images for minutiae extraction, we detect minutiae straightaway from the binarized fingerprint images using EDT. We also use EDT values to get rid of spurs and bridges in the fingerprint image. Unlike many other previous methods, our work depends minimally on arbitrary selection of parameters.
CLASSIFICATION OF TANGLE SOLUTIONS FOR INTEGRASES, A PROTEIN FAMILY THAT CHANGES DNA TOPOLOGY
Authors: BUCK DOROTHY , MARCOTTE CYNTHIA VERJOVSKY
Published: November 2007

A generic integrase protein, when acting on circular DNA, often changes the DNA topology by transforming unknotted circles into torus knots and links. Two systems of tangle equations — corresponding to two possible orientations of two DNA subsequences — arise when modelling this transformation.

With no a priori assumptions on the constituent tangles, we utilize Dehn surgery arguments to completely classify the tangle solutions for each of the two systems. A key step is to combine work of our previous paper [10] with recent results of Kronheimer, Mrowka, Ozsváth and Szabó [39] and work of Ernst [23] to show a certain prime tangle must in fact be a Montesinos tangle.

These tangle solutions are divided into three classes, common to both systems, plus a fourth class for one system that contains the sole Montesinos tangle. We discuss the possible biological implications of our classification, and of this novel solution.
IMPROVING USER RESPONSE TIMES IN APPLICATION DELIVERY NETWORKS THROUGH REDUCTION OF NETWORK AND SERVER LATENCIES
Authors: SELÇUK CANDAN K. , LI WEN-SYAN , AGRAWAL DIVYAKANT
Published: November 2007

An application delivery network (ADN) consists of a set of servers distributed over a large wide area network. In general, ADNs employ two approaches to improve performance in terms of response time: (1) use topological proximity on the network to redirect clients to a closest server, and (2) balance the load of the servers in the original source or the content delivery network using a load balancing algorithm. These two approaches aim to minimize the two major parameters, network latency and server latency, respectively. To accelerate delivery of static content, network latency is the major parameter to minimize. However, to accelerate delivery of dynamically generated content, both parameters are important and a solution requires to achieve a balance between these two approaches. In this paper, we illustrate the need for an integrated approach to this problem. We describe methods for improving the observed performance of an application delivery network by assigning the end user requests to servers. We describe an algorithm which computes such assignments efficiently, so that the assignment task can be performed and adjusted often as the environment changes. The experimental results show that the assignment computation is accurate and close to the optimal.
AN EMPIRICAL STUDY OF HIERARCHICAL DIVISION FOR MESH-STRUCTURED NETWORKS
Authors: WANG DAJIN
Published: November 2007

A parallel/distributed system consists of a collection of processes, which are distributed over a network of processors, and work in a cooperative manner to fulfill various tasks. A hierarchical approach is to group and organize the distributed processes into a logical hierarchy of multiple levels to achieve better system performance. It has been proposed as an effective way to solve various problems in distributed computing, such as distributed monitoring, resource scheduling, and network routing. In [21], we studied hierarchical configuration for mesh and hypercube networks to the end of achieving better system performance. In particular, we proposed theoretically optimal hierarchy for mesh and hypercube, so that the total traffic flow over the network is minimized.

In this paper, we present the experimental results to establish the practical relevance of mesh hierarchy proposed in [21]. We simulated situations for multi-level division, real network loading scenarios, random data aggregation rates, and different division sizes other than derived in [21]. The simulation results not only show that the analytically obtained hierarchy works well for many realistic settings, but also offer some useful insights into the proposed hierarchy scheme.
COMPARATIVE STUDY OF WAVELET BASED NEURAL NETWORK AND NEURO-FUZZY SYSTEMS
Authors: BANAKAR AHMAD , AZEEM MOHAMMAD FAZLE , KUMAR VINOD
Published: November 2007

Based on the wavelet transform theory and its well emerging properties of universal approximation and multiresolution analysis, the new notion of the wavelet network is proposed as an alternative to feed forward neural networks and neuro-fuzzy for approximating arbitrary nonlinear functions. Earlier, two types of neuron models, namely, Wavelet Synapse (WS) neuron and Wavelet Activation (WA) functions neuron have been introduced. Derived from these two neuron models with different non-orthogonal wavelet functions, neural network and neuro-fuzzy systems are presented. Comparative study of wavelets with NN and NF are also presented in this paper.
ROTATIONAL WAVELET BANK FOR EDGE DETECTION
Authors: ZHANG LIMING
Published: November 2007

The Morlet rotational integral wavelet transform was proved, in both practice and mathematical theory, to be effective to detect edges with certain directions. The present paper studies a bank of rotational wavelets of which each is similar to the Morlet wavelet. Experiments are carried out for a number of classical functions in mathematical analysis. They show the effectiveness of the rotational method with different types of kernel functions.
MONO-COMPONENT DECOMPOSITION OF SIGNALS BASED ON BLASCHKE BASIS
Authors: LI HONG , LI LUOQING , TANG YUAN Y.
Published: November 2007

This paper mainly focuses on decomposition of signals in terms of mono-component signals which are analytic with strictly increasing nonlinear phase. The properties of Blaschke basis and the approximation behavior of Blaschke basis expansions are studied. Each Blaschke product is analytic and mono-component. An explicit expression of the phase function of Blaschke product is given. The convergence results for Blaschke basis expansions show that it is suitable to approximate a signal by a linear combination of Blaschke products. Experiments are presented to illustrate the general theory.
QUANTUM TELEPORTATION OF AN ARBITRARY N-QUBIT STATE VIA NON-MAXIMALLY ENTANGLED STATE
Authors: LIU YU-LING , MAN ZHONG-XIAO , XIA YUN-JIE
Published: November 2007

We explicitly present two schemes for quantum teleportation of an arbitrary N-qubit entangled state using, respectively, non-maximally entangled Bell states and GHZ states as the quantum channels, and generalized Bell states as the measurement basis. The scheme succeeds with unit fidelity but less than unit probability. By introducing additional qubit and unitary operations, the success probability of these two schemes can be increased.
FUZZY PARAPROXIMITY SPACES
Authors: KANDIL A. , TANTAWY O. , BARAKAT K.
Published: November 2007

We introduce the concept of a fuzzy completely normal space or FT5-space and fuzzy paraproximity space showing that every fuzzy paraproximity space induces a fuzzy completely normal space and vice versa.
ASSESSMENT INSTRUMENTS AS PREDICTORS OF SUCCESS FOR CHILDREN WITH HEARING IMPAIRMENT IN THE MAINSTREAM CLASSROOM: A FUZZY MATHEMATICS APPROACH
Authors: MORDESON JOHN N. , HOUTZ LYNNE E. , ROSSI KAREN K. , VOSS JENNA M. , BURTON LISA R.
Published: November 2007

We use for the first time fuzzy mathematics to aid in the determination of which tests of preschool, hard of hearing and deaf children are the best predictors of success when these students are mainstreamed in the public school system. The techniques are those of group decision making and consensus under fuzzy preferences and fuzzy majority and techniques of fuzzy outranking relations in preference modelling.
THE NATURAL OPERATIONS OF LINGUISTIC LOGIC
Authors: HSIEH CHIH HSUN
Published: November 2007

A linguistic truth set in which each element is a linguistic truth value is discussed. Ranking linguistic truth values based on Graded Mean Integration Representation method is discussed also. We then give a decreasing linguistic truth set and an increasing linguistic truth set by using the above ranking method, and present a Not function of linguistic truth value combined by the above decreasing linguistic truth set and the increasing linguistic truth set. A minimum function and a maximum function based on representations of linguistic truth values are introduced. In addition, some natural operations of linguistic logic combined by minimum function and maximum function, and Not function are presented. Some properties of our presented natural operations are presented, and are proved. Furthermore, some application examples of linguistic logical statements are discussed finally.
ENERGY TRANSDUCTION IN MOLECULAR MACHINES
Authors: CHANG CHENG-HUNG , TSONG TIAN YOW
Published: November 2007

An applied force may cause the conformation and thus, the activity of a biological molecule to change. Here we consider a system in which an oscillating or fluctuating electric field is used to actuate membrane protein activities. Most proteins have electric dipoles and net charges in the structure and their conformations are susceptible to the electric and magnetic perturbation. The shape of a cell may also amplify an electric field across its plasma membrane. Therefore, a membrane integral protein such as an ion channel, an ion pump, or a molecular motor, is especially amenable to electric perturbation. The theory of electroconformational coupling addresses the functional implication of this field effect. When an alternating electric field or a fluctuating electric field is employed to actuate a two-state protein oscillator, the dynamics of the conformational change of the protein can be synchronized with the applied field. Through this two-state protein oscillator, we construct a four-state catalytic wheel by coupling an energy transducer mechanism to the two-state protein oscillator. Analysis shows that the catalytic wheel can extract energy from a disordered external energy source, be it electrical, mechanical, or chemical, and convert this stochastic energy source to a usable energy format. The catalytic wheel is tested with the experimental data on the electric field-stimulated cation pumping of Na , K -ATPase. A dipole ratchet model based on the electroconformational coupling concept will also be discussed and compared with the ATP-dependent rotation of a rotary motor F1-ATPase. Since the working principle of this model is simpler than that of F1-ATPase, it provides an easier way to realize a nanoscale rotary motor than artificially reconstructing a F1-ATPase.
Multifractal power spectrum and singularity analysis for modelling stream sediment geochemical distribution patterns to identify anomalies related to gold mineralization in Yunnan Province, South China
Authors: Ali Khaled , Cheng Qiuming , Chen Zhijun
Published: November 2007

Abstract:
Two multifractal modelling methods are applied to stream sediment geochemical data from the Zhenyuan gold mineral district, Yunnan Province, South China. In the first method, the ‘Singularity Index’ (α) has been applied for characterizing local structural properties of geochemical maps such as areas characterized by enriched or depleted geochemical concentrations. In the other method, a Spectrum–Area (S-A) method was applied to decompose geochemical element grid maps into background and anomaly maps. The latter are related to gold mineralization. These two methods are demonstrated in this paper and outputs of the research have provided targeted areas for further exploration.
Measurement of Pb isotope ratios by continuous leach–inductively coupled plasma–mass spectrometry: quantification of precision and accuracy
Authors: MacFarlane W.R. , Kyser T.K. , Chipley D.
Published: November 2007

Precision and accuracy have been quantified for the determination of lead isotope ratios using continuous leach–inductively coupled plasma–mass spectrometry (CL-ICP-MS) by optimizing acquisition parameters and minimizing the number of elements in the method. By analysing for only
204
Pb,
206
Pb,
207
Pb,
208
Pb,
200
Hg, and
202
Hg, counting times can be increased allowing improvements in isotope ratio precision over normal CL-ICP-MS determinations, which measure these elements as part of a much larger suite. At total Pb concentrations of 1 ppb in solution, results show that precisions of 6.7% to 8.3% and 7.8% to 21% can be achieved for
207
Pb/
206
Pb and
207
Pb/
204
Pb, respectively, over the 0% to 30% HNO
3
concentrations used in CL-ICP-MS. Accuracy, as measured against the certified values for NIST 981, ranges from 0.5% to 1.4% and 1.4% to 21% for
207
Pb/
206
Pb and
207
Pb/
204
Pb, respectively. The improvement in precision and accuracy afforded by this technique allows greater differentiation of isotopically distinct reservoirs of Pb within natural samples collected for exploration and environmental geochemistry.
Strategies for reducing sampling errors in exploration and resource definition drilling programmes for gold deposits
Authors: Stanley Clifford R. , Smee Barry W.
Published: November 2007

Sampling error is the degree to which the concentration of an element differs from the true element concentration of the material from which the sample was collected. Gold mineralization commonly exhibits sampling errors as large as 50–100%. As a result, collection and preparation of drill samples from Au mineralization can provide significant challenges for the geoscientist, largely because of the coarse particulate nature of Au. To avoid this, geoscientists have opted to collect and prepare larger drill samples to reduce the magnitude of this ‘nugget effect’. Unfortunately, the ‘nugget effect’ can cause sampling error at any stage of sample treatment when sub-sampling takes place. Knowledge of the magnitude of error at each sub-sampling step is necessary to identify strategies to reduce overall error. This is because reduction of only the largest component of measurement error will reduce total measurement error in the most numerically efficient and effective manner. With knowledge of the various components of sampling, preparation and analysis costs, the sample treatment strategy that will most cost-effectively reduce sampling error can be identified. Regrettably, the typical absolute and relative errors that occur during sample collection and preparation of sub-samples with finer particle sizes are not generally known for many Au deposits.

Results from three Au drilling projects document the magnitude of sampling, preparation and analytical errors experienced, and range from 22 to 46%, 7 to 20%, and 1 to 13%, respectively. These results are derived from large, laboratory-blind, duplicate quality control/quality assessment (QA/QC) programmes involving sample treatment protocols that would be considered to be appropriate for coarse Au-bearing samples. These QA/QC programmes measured the sampling errors, and ensured that they were minimized on these projects.

In general, results indicate that a very large component of total measurement error is introduced during the collection of the initial sample, and that subordinate amounts of error are introduced during preparation and analysis. As a result, undertaking extraordinary efforts to reduce preparation or analytical errors does not result in a significant total measurement error reduction. In contrast, the collection of larger initial samples can result in the substantial reduction of total measurement error.
Rutile compositions at the Big Bell Au deposit as a guide for exploration
Authors: Scott Keith M. , Radford Nigel W.
Published: November 2007

The compositions of 277 grains of rutile from 24 samples from the Big Bell Au deposit and nearby smaller deposits, in the Murchison Province of Western Australia, reveal that rutiles associated with ore at Big Bell, and for up to 200 m into the footwall rocks, are V+Fe+W+Sb-rich – a characteristic of rutile that has previously only ever been documented at the Hemlo Au deposit in Canada. Rutile from the nearby Fender and Indicator deposits share this Big Bell-type signature, but that from North Fender contains Nb±Ta, with W and Fe, suggesting formation from a quite different fluid and at a different period. The preservation of the different types of rutile in regolith samples in the Big Bell region indicates that it is possible to discriminate between the V+Fe+W+Sb-rich and Fe+Nb±Ta-rich alteration in rutile using regolith samples.