CAD Method Research Articles

Analysis of tandem mass spectra by FTMS for improved large-scale proteomics with superior protein quantification.

Using a newly developed dual-cell quadrupole linear ion trap-orbitrap hybrid mass spectrometer (dcQLT-orbitrap), we demonstrate the utility of collecting high-resolution tandem mass spectral data for large-scale shotgun proteomics. Multiple nanoLC-MS/MS experiments on both an older generation quadrupole linear ion trap-orbitrap hybrid (QLT-orbitrap) and the dcQLT-orbitrap, using both resonant-excitation CAD and beam-type CAD (HCD), were performed. Resulting from various technological advances (e.g., a stacked ring ion guide AP inlet, a dual cell QLT), the dcQLT-orbitrap exhibited increased duty cycle (approximately 1.5-2 times) and sensitivity for both CAD (ion trap detection) and HCD (orbitrap detection) methods. As compared to the older system, the dcQLT-orbitrap produced significantly more unique peptide identifications for both methods (approximately 30% improvement for CAD and approximately 115% improvement for HCD). The sizable improvement of the HCD method on the dcQLT-orbitrap system outperforms the current standard method of CAD with ion trap detection for large-scale analysis. Finally, we demonstrate that the increased HCD performance translates to a direct and substantial improvement in protein quantitation precision using isobaric tags.

Novel Computer-Aided Diagnosis Algorithms on Ultrasound Image: Effects on Solid Breast Masses Discrimination

The objective of this study is to retrospectively investigate whether using the newly developed algorithms would improve radiologists' accuracy for discriminating malignant masses from benign ones on ultrasonographic (US) images. Five radiologists blinded to the histological results and clinical history independently interpreted 226 cases according to the sonographic lexicon of the fourth edition of the Breast Imaging Reporting and Data System and assigned a final assessment category to indicate the probability of malignancy. For each case, each radiologist provided three diagnoses: first with the original images, subsequently with the assistant of the resulting images processed by the proposed CAD algorithms which are called as processed images, and another using the processed images only. Observers' malignancy rating data were analyzed with the receiver operating characteristic (ROC) curve. For reading only with the processed images, areas under the ROC curve (A(z)) of each reader (0.863, 0.867, 0.859, 0.868, 0.878) were better than that with the original images (0.772, 0.807, 0.796, 0.828, 0.846), difference of the average A(z) between the twice reading was significant (p < 0.001). Compared with the results single used processed images, A(z) of utilizing the combined images were increased (0.866, 0.885, 0.872, 0.894, 0.903), but the difference is not statistically significant (p = 0.081). The proposed CAD method has potential to be a good aid to radiologists in distinguishing malignant breast solid masses from benign ones.

Computer-aided diagnosis of lumbar disc pathology from clinical lower spine MRI

Detection of abnormal discs from clinical T2-weighted MR Images. This aids the radiologist as well as subsequent CAD methods in focusing only on abnormal discs for further diagnosis. Furthermore, it gives a degree of confidence about the abnormality of the intervertebral discs that helps the radiologist in making his decision. We propose a probabilistic classifier for the detection of abnormality of intervertebral discs. We use three features to label abnormal discs that include appearance, location, and context. We model the abnormal disc appearance with a Gaussian model, the location with a 2D Gaussian model, and the context with a Gaussian model for the distance between abnormal discs. We infer on the middle slice of the T2-weighted MRI volume for each case. These MRI scans are specific for the lumbar area. We obtain our gold standard for the ground truth from our collaborating radiologist group by having the clinical diagnosis report for each case. We achieve over 91% abnormality detection accuracy in a cross-validation experiment with 80 clinical cases. The experiment runs ten rounds; in each round, we randomly leave 30 cases out for testing and we use the other 50 cases for training. We achieve high accuracy for detection of abnormal discs using our proposed model that incorporates disc appearance, location, and context. We show the extendability of our proposed model to subsequent diagnosis tasks specific to each intervertebral disc abnormality such as desiccation and herniation.

Performance Evaluation of Charged Aerosol and Evaporative Light Scattering Detection for the Determination of Ginsenosides by LC

A sensitive LC-CAD method was developed for simultaneous determination of seven major triterpenoid saponins, namely ginsenosides Rg1, Re, Rb1, Rc, Rb2, Rb3 and Rd in Panax ginseng C. A. Meyer, a commonly used traditional Chinese medicine. This CAD method was evaluated in sensitivity, linearity and reproducibility compared to ELSD and UV. It was found the developed method has improved sensitivity, linearity and reproducibility compared to ELSD. This method was successfully applied to analyze the ginsenosides in ten samples of Panax ginseng. The validation results indicated that the improved method can be utilized as another approach for quality control of P. ginseng.

Implementation of a Low Loss Microstrip to Waveguide Transition in X-band using CAD Methods

In this paper, a microstrip to waveguide transition in X-band by a coaxial probe is proposed. The effects of coaxial probe along with a bush added to the excitation probe inside the waveguide in improving the performance of the transition are investigated. In addition, the effect of imperfect connection between waveguide and microstrip substrate to achieve the best matching over the desired bandwidth is examined. The proposed structure is designed and is analyzed using Ansoft HFSS10 and CST Studio Suite 2008. Measurement results for scattering parameters are in agreement with simulation results.

Real‐time motion tracking in image‐guided oral implantology

As a crucial part of an image-guided oral implantology system (IGOIS), intra-operative motion tracking is important in terms of accuracy and efficiency. The tracking method, including the relevant algorithms, is described in detail. The conventional CAD method is proposed to build the three-dimensional (3D) surgical instrument models. With the application of the optical tracking device, calibration can be carried out. Three tracking algorithms are presented, and 'tracking based on registration of RCS to VCS' is regarded as the most efficient of these. In order to evaluate the tracking accuracy, the landmark coordinates are respectively obtained through pre-operative CT data and intra-operative tracking, so that the deviation can be calculated. The result data reveal that FRE and TRE of IGOIS are, respectively, 0.27 +/- 0.11 mm and 0.77 +/- 0.04 mm through a phantom experiment. The experiment demonstrates the accuracy and reliability of IGOIS. The tracking method can be extended to other surgical navigation systems in various areas.

Computer Aided Investigation towards the Wind Power Generation Potentials of Guangzhou

Wind power generation potential of Guangzhou has been analyzed based on the wind speed data collected in the recent 30 years. In order to make the results more accurate, the Weibull distribution function is introduced and the two parameters can be identified by CAD method together with local weather data available. By referring to the power characteristics of the wind turbines, the monthly and yearly operating probabilities and the output power under different heights are analyzed. Given by the above data and the power generation cost, it is proved that although the wind power resources in Guangzhou is not very ideal, it can also be utilized to generate power.

On the application of CAD technology for the synthesis of spatial revolute–revolute dyads

This work presents a method based on Computer Aided Design or CAD for facilitating the synthesis of Revolute–Revolute (R–R) dyads with adjustable moving pivots. The CAD-based method presented in this work ensures that all prescribed rigid-body parameters used to synthesize the R–R dyad satisfy particular kinematic requirements of an R–R dyad. Through the application of this CAD method, five of the six general R–R dyad constraint equations are satisfied and therefore not essential for the synthesis of the R–R dyad. By reducing the number of dyad design constraints from six to one, the user can synthesize R–R links with adjustable moving pivots for multi-phase motion and path generation applications. The example included demonstrates the use of the CAD method in the synthesis of an RRSS path generator with adjustable moving pivots.

Novel distributed circuit model for transition between coplanar waveguide and microstrip by using the generalized telegrapher equation method

AbstractIn this article, a novel distributed circuit model of coplanar waveguide to microstrip (CPW‐M) transition is presented by using generalized telegrapher equation. In comparison with conventional nonuniform transmission line equation, the generalized telegrapher equation has two additional terms, dependent series voltage and shunt current sources, which represent local radiation effect from discontinuities of the nonuniform transmission line itself. Based on the full‐wave numerical results, the distributed circuit parameters can be extracted by using the generalized telegrapher equation. Since the generalized telegrapher equation coefficients are determined by dynamic numerical methods and the coefficients are invariant with the line excitation and load, the equation is dynamical rather TEM. The numerical experiments show that the novel distributed circuit model for this CPW‐M transition can have broadband characteristics. As a preparatory experiment, an improved CAD method using this model is utilized to model different structures of CPW‐M transition. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1323–1328, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22461

GeoTran-HC: Geometric transformation of highly coupled variable topology multi-body problems

Manipulating geometry to prepare a CAD design model for mesh generation is an important step in the finite element analysis (FEA) process. However, complex problems such as electronic chip packages often consist of hundreds or even thousands of sub-features with varying materials, complex geometrical shapes and changeable connectivity configurations. We define a subclass of such problems, termed highly coupled variable topology multi-body (HCVTMB) problems, where configuration and relative geometric sizes cause meshing changes in one body to propagate throughout much of the model. Today creating FEA models for HCVTMB problems typically requires manual geometrical manipulation which is labour-intensive and error-prone. In this paper we introduce an automated geometric transformation method–GeoTran-HC–within the context of a knowledge-based modeling method for CAD–FEA integration. Through five steps–geometry extraction, cell decomposition, associativity maintenance, feature recognition and associativity recovery–this transformation method automatically decomposes an HCVTMB analytical model into a meshable model. It also manages mesh quality and attribution of non-geometrical information such as material properties and boundary conditions. A plastic ball grid array chip package thermo-mechanical case study demonstrates the efficacy of GeoTran-HC within the context of our knowledge-based FEA modelling method. This and similar studies show reductions in total FEA modeling time from days/hours (using traditional methods) to hours/minutes (using the presented method), as well as enhanced modularity and reusability.

Contribution of sagittal orientation of facet joints and disc degeneration to degenerative spondylolisthesis in lumbar spine: A finite element research

目的 探讨小关节矢状化与椎间盘退变间的关系及其对退变性腰椎滑移的作用和意义.方法 采用一种新型CAD方法精确构建65°小关节角、45°小关节角、25°小关节角与正常椎间盘、轻度退变椎间盘、重度退变椎间盘相组配的9种腰椎L4-L5活动节段有限元模型.生理压缩载荷下,分别对9种有限元模型的生物力学参数进行测试.结果 与小关节角45°和25°有限元模型相比,小关节角65°有限元模型的矢状方向椎体前移位增加,关节突、峡部等效应力和关节突水平方向接触力明显增加;小关节角65°有限元模型的终板膨出减小,纤维环基质应力增加.与正常有限元模型相比,椎间盘轻度退变有限元模型刚度下降,小关节突及峡部应力轻度增加.9种有限元模型中,轻度退变椎间盘结合小关节角65°有限元模型的抗前剪力能力最差.结论 小关节角矢状化既是退变性腰椎滑移的原发诱因,又是局部应力变化导致关节突再塑形的继发病理改变,矢状型小关节腰椎活动节段矢状方向内在不稳定性受椎间盘退变程度的影响,椎间盘退变对小关节角矢状化无明显促进作用。

Development of an Integrated System for the Automated Design of a Gerotor Oil Pump

A gerotor pump is suitable for oil hydraulics of machine tools, automotive engines, compressors, construction, and other various applications. In particular, the pump is an essential machine element that feeds lubricant oil in an automotive engine. The main components of the pump are the two rotors. Usually, the outer one is characterized by lobes with a circular shape, while the inner rotor profile is determined as a conjugate to the other. In this study, the design optimization has been carried out to determine the design parameters that maximize the specific flow rate and minimize the flow rate irregularity. The integrated system, which is composed of three main modules, has been developed through AutoLISP, Visual Basic language, and the CAD method, and considers various design parameters. An optimally designed model for a general type of gerotor pump has been generated and experimentally verified for its pump performances. Results obtained using the system enable the designer and manufacturer of the oil pump to be more efficient in this field.

Intrinsic topological representation of real algebraic surfaces

Determining the topology of an algebraic surface is not only an interesting mathematical problem, but also a key issue in computer graphics and CAGD. An algorithm is proposed to determine the intrinsic topology of an implicit real algebraic surface f ( x,y,z ) = 0 in R 3 , where f ( x,y,z ) ∈ Q [ x,y,z ] and Q is the field of rational numbers. There exist algorithms to determine the topology for algebraic surfaces of special type [2, 3, 4, 7]. The CAD method proposed by Collins [1] can divide the space into cylindrical parts. But it does not give the connection information neither the intrinsic representation.

SU‐FF‐I‐03: Evaluation of Computer Aided Diagnosis On Thin‐Slice Pulmonary CT Images

Purpose: Pulmonary stereotactic radiation therapy achieves a &gt;90% local control rate for small tumors (&lt;30mm); motivating early detection of small lung nodules. With the increasing image resolution afforded by multi‐slice CT scanners, radiologists can discern more easily these very small lung nodules. However, to overcome the challenge of image overload, assistance from lung CAD systems becomes a necessity. The purpose of this work is to evaluate the performance of our lung CAD algorithm on low‐dose, thin‐slice CT images from the Early Lung Cancer Action Program (ELCAP) database. Method and Materials: Our CAD algorithm models lung nodules as spheres (a modification of the 3D template‐matching method presented in AAPM'03) and searched for structures similar to the templates throughout the whole lung volume. This approach eliminates the need for segmentation of blood vessel‐nodule complex and is insensitive to noise and low‐contrast of some nodules. In the extraction of lung volume, a watershed transform was applied to separate left and right lungs when necessary. A 3D spherical structure element was used to smooth out the surface of both lungs in order to incorporate pleural nodules. An improved padding scheme was adapted on the templates to make the detection capacity of templates more isotropic. A test dataset was used, consisting of 55 central contiguous slices (voxel size: 0.57×0.57×1.25mm3) from a particularly challenging subject in the ELCAP database. 41 nodules were identified by an experienced radiologist from our institution. Results: 37 out of 41 nodules were detected by our CAD algorithm, a sensitivity of 90.2%. Among them, 28 out of 32 nodules with diameter &lt;3mm were detected. The smallest detected nodule had a diameter of only ∼3 pixels (1.7mm) and a volume of ∼17 voxels. Conclusion: Our CAD method is capable of detecting with high sensitivity very small lung nodules in low‐dose thin‐slice chest CT.

Deamidation: Differentiation of aspartyl from isoaspartyl products in peptides by electron capture dissociation

Deamidation of asparaginyl and isomerization of aspartyl residues in proteins proceed through a succinimide intermediate producing a mixture of aspartyl and isoaspartyl residues. Isoaspartic acid is an isomer of aspartic acid with the C(beta) incorporated into the backbone, thus increasing the length of the protein backbone by one methylene unit. This post-translation modification is suspected to contribute to the aging of proteins and to protein folding disorders such as Alzheimer's disease, so that differentiating the two isomers becomes important. This manuscript reports that distinguishing aspartyl from isoaspartyl residues in peptides has been accomplished by electron capture dissociation (ECD) using a Fourier transform mass spectrometer (FTMS). Model peptides with aspartyl residues and their isoaspartyl analogs were examined and unique peaks corresponding to c(n)*+58 and z(l-n)-57 fragment ions (n, position of Asp; l, total number of amino acids in the peptide) were found only in the spectra of the peptides with isoaspartyl residues. The proposed fragmentation mechanism involves cleavage of the C(alpha)-C(beta) backbone bond, therefore splitting the isoaspartyl residue between the two fragments. Also, a complementary feature observed specific to aspartyl residues was the neutral loss of the aspartic acid side chain from the charge reduced species. CAD spectra of the peptides from the same instrument demonstrated the improved method because previously published CAD methods rely on the comparison to the spectra of standards with aspartyl residues. The potential use of the top-down approach to detect and resolve products from the deamidation of asparaginyl and isomerization of aspartyl residues is discussed.

3813 非円形歯車のCAD(S70-2 新しい設計支援技術(2),S70 新しい設計支援技術)

As a non-circular gear is equipped the motional characteristics of both cam and circular gear, it can be used for transmitting rotary motion at a variable rate in an instrument or a machine. This paper describes a CAD method for non-circular gears. It consists of: (1) Necessity and purposes of the research, (2) Mechanism of non-circular gears and the relationship between a shape and its transmission motion or velocity, (3) Design of teeth and pitch curves, such as an involute curve as a tooth curve, and an ellipse or a free-form curve of B-spline as a pitch curve defined by analytical geometry methods, (4) Calculation and adjustment of the number of teeth, (5) Distribution and trimming of teeth, (6) Creation of 3D models of the gears and (7) Discussions and conclusions.

Reducing Whole-Body Vibration by Geometric Repair of Pavements

Many road users suffer from back pain, fatigue, drowsiness and motion sickness. Such problems are often related to low frequency vibration. While vehicle suspension systems efficiently isolate vibration caused by road texture and short-wave roughness, they often amplify vibration at lower frequencies. Sources of these motions are large variance of cross fall and long-wave roughness; geometric road features longer/wider than vehicle body dimensions. Traditional 35 mm asphalt overlay only partially reduces such road damage, while repairing short-wave roughness efficiently. The most efficient method to reduce vehicle low frequency vibration is geometric large-scale repair of pavements. This paper presents a method for such road repair, using Computer Aided Design of the levelling course and milling works. Use of the CAD method offers an opportunity to – within the road managers' budget frame – optimize road repair to reduce human whole-body vibration in vehicles.

Numerical algorithms for boundary problems with disturbed axial symmetry

The axial symmetry in the real devices of image electron optics is always disturbed by small defects in manufacturing and assembly. We present a complete method for the numerical simulation of problems with such defects, which includes the algorithms for singularity extraction in a numerical solution of the boundary problem described by the Helmholtz equation. The effective recurrent formulas for evaluation of the kernels of integral representations and their derivatives are constructed. New modification of the well-known Bruns–Bertein (Crelles J. Math. 81 (1876) 349; Ann. de Radioelectr. 2 (7) (1947) 379) method is given, and correlation of this method with an integral equation in variations is investigated. The algorithms are implemented in the codes POISSON-2 (CAD Methods in Physical Electronics—2 parts, Inst. Math. RAS, Novosibirsk, 1986; Proceedings of the 2nd International Conference on Computations in Electromagnetism, Notingham, UK, May 13–15, 1994; Proceedings of the 11th IEEE International Pulsed Power Conference, Baltimore, MD, June 29–July 2, 1997) and OPTICS-2 (Proceedings of the XV Conference on High Speed Photography, Photonics and Metrology of High-Speed Processes, Moscow, 26–29 November, 1991). The results of the numerical simulation for various test problems with different kinds of boundary deformation are given.

Research on the Multi-Objective Optimal Control for Electric Drive System

This paper gives a X--Q non--linear controller and CAD method for the Multi--objective Control Systems. Then discusses how to use the X--Q controller to perform it. Finally, In this paper an example of a DC electric drive system designed with CAD multi-objective optimal design method is given. The performance checked by computer simulation shows that the performance of multi-objective optimal system is better than that of linear optimal system .The design method is simple and easy, universal and suitable for engineering design.

Numerically distributed circuit parameters model on microstrip transmission line circuits and its application on CAD

AbstractA new numerical model of microstrip transmission line circuits in terms of distributed circuit parameters is here illustrated. Based on full‐wave electromagnetic results, the extraction methods of these distributed circuit parameters on different types of microstrip transmission line circuits are introduced. As a preparatory experiment, an improved CAD method using this model is tested on microstrip low‐pass filter. Copyright © 2003 John Wiley &amp; Sons, Ltd.