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Search Results: 1 - 10 of 211 matches for " Eigen Imperfection Shapes "
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Post-Buckling Behavior of Laminated Composite Cylindrical Shells Subjected to Axial, Bending and Torsion Loads  [PDF]
Yengula Venkata Narayana, Jagadish Babu Gunda, Ravinder Reddy Pinninti, Markandeya Ravvala
World Journal of Engineering and Technology (WJET) , 2015, DOI: 10.4236/wjet.2015.34019
Abstract: In present work, post-buckling behavior of imperfect (of eigen form) laminated composite cylindrical shells with different L/D and R/t ratios subjected to axial, bending and torsion loads has been investigated by using an equilibrium path approach in the finite element analysis. The Newton-Raphson approach as well as the arc-length approach is used to ensure the correctness of the equilibrium paths up to the limit point load. Post-buckling behavior of imperfect cylindrical shells with different L/D and R/t ratios of interest is obtained and the theoretical knock-down factors are reported for the considered cylindrical shells.
Complex Object Shapes Recognition. Automatic Aid Photointerpretation in a Satellite Image  [PDF]
Macho Anani, Kada Mouedden, Youcef Amar, Sara Lebid, Mohammed Benyahia
International Journal of Geosciences (IJG) , 2012, DOI: 10.4236/ijg.2012.31003
Abstract: The interpretation of geological structures on earth observation images involves like many other domains to both visual observation as well as specialized knowledge. To help this process and make it more objective, we propose a method to extract the components of complex shapes with a geological significance. Thus, remote sensing allows the production of digital recordings reflecting the objects’ brightness measures on the soil. These recordings are often presented as images and ready to be computer automatically processed. The numerical techniques used exploit the morphology ma- thematical transformations properties. Presentation shows the operations’ sequences with tailored properties. The example shown is a portion of an anticline fraction in which the organization shows clearly oriented entities. The results are obtained by a procedure with an interest in the geological reasoning: it is the extraction of entities involved in the observed structure and the exploration of the main direction of a set of objects striking the structure. Extraction of elementary entities is made by their physical and physiognomic characteristics recognition such as reflectance, the shadow effect, size, shape or orientation. The resulting image must then be stripped frequently of many artifacts. Another sequence has been developed to minimize the noise due to the direct identification of physical measures contained in the image. Data from different spectral bands are first filtered by an operator of grayscale morphology to remove high frequency spatial components. The image then obtained in the treatment that follows is therefore more compact and closer to the needs of the geologist. The search for significant overall direction comes from interception measures sampling a rotation from 0 to 180 degrees. The results obtained show a clear geological significance of the organization of the extracted objects.
改进的特征值灵敏度在结构损伤识别中的应用
Structure Damage Detection Based on Improved Eigen Value Sensitivity

邱飞力,张立民,张卫华
- , 2016, DOI: 10.16450/j.cnki.issn.1004-6801.2016.02.009
Abstract: 传统的特征值灵敏度分析中忽略了振型变化的影响,导致特征值灵敏度难以准确地识别出结构损伤。为提高特征值灵敏度的准确性,利用未损伤结构的振型线性表示损伤情况下结构振型的变化,进而改进了特征值灵敏度的理论分析方法。在不同的损伤工况下,计算数值模型改进前后的特征值灵敏度,验证表明改进后的特征值灵敏度具有更高的精度。以孔洞直径和位置均未知的实际结构为研究对象,利用改进后灵敏度方法准确识别了结构损伤的位置和程度,与结构的孔洞直径和位置实测值相吻合,表明了改进后灵敏度方法具有准确实用性,从而弥补了传统特征值灵敏度法在结构损伤识别中的缺陷。
As structural damage may affect performance and even lead to structural failure, the identification of structural damage is crucial. Testing mode parameters such as mode eigen values, natural frequencies and mode shapes is simple and convenient. It makes more sense for the eigen value to be objective for damage detection due to its higher sensitivity for structural damage compared with natural frequencies and mode shapes. However, it was difficult to use the traditional eigen value sensitivity method to identify structural damage accurately, because it was easy to ignore the change of mode shape. In order to improve its accuracy, the change of structure mode shape could be substituted with the linear combination of undamaged structure mode shapes, thus improving the eigen value sensitivity analysis method. The traditional and improved sensitivity was calculated under various damage conditions, and the comparison showed higher accuracy. The improved eigen value sensitivity method was applied to a real structure with holes of unknown size and location. The identified results showed that the accurate damage level and location were identified, thus validating the accuracy and practicability of this improved sensitivity method.
Da imperfei o, ou o complexo de Babel
Luís Adriano Carlos
CEM : Cultura, Espa?o & Memória , 2010,
Abstract: Based on a novel published in the beginning of the Millennium – A Imperfei o, by Jo o Paulo Sousa –, the author critically reflects on the problem of ethic and aesthetic communication, framed by a reinterpretation of the myth of Babel as the symbolic and blessed origin of the cultural and literary universe. The novel’s characters, taken to be symbols of contemporary society, struggle with the imperfection of words , representing themselves as foreign beings devoured by the misunderstanding of communication. However, it is on the journey across the dream of a perfect language that they are marooned, victims of their unconditional belief in the ideology of identity and unicity that characterize our times of globalization.
Characterization of Phosphide Platelets in Eutectic Sand Cast Cu-Sn-P Alloy  [PDF]
L. O. Mudashiru, T. M. Azeez, S. O. Afolabi, I. A. Babatunde
International Journal of Nonferrous Metallurgy (IJNM) , 2015, DOI: 10.4236/ijnm.2015.43004
Abstract: A procedure for evaluating the degree of spheroidization of phosphide platelets in cast Cu-4%Sn- 5%P alloys using fractal analysis was investigated. The specimens were obtained by melting copper and tin in an improvised clay mould raised to a temperature of 1850°C ± 20°C, holding for a period of 10 minutes to 1 hour to modify the aspect ratio of the phosphide platelets. It was found that these platelets have the tendency to change their shape from being spherical to more Euclidian shapes as time elapses. It was found that the inter-platelets distances are approximately equal with time. This effect was more pronounced in samples with high holding time.
IPO Stocks Performance Imperfection: A Review of Models and Empirical Works  [PDF]
Alex A. A. Bruce, P. M. C. Thilakaratne
American Journal of Industrial and Business Management (AJIBM) , 2014, DOI: 10.4236/ajibm.2014.43022
Abstract:

Performance of IPO stocks is determined by the returns on a firm’s IPOs and other subsequent issues. Returns are derived from the price swings (volatility) as compared to the offer price so that a favourable swing indicates favourable returns and vice-versa. In the light of this, we review models and empirical works that try to explain these swings and their consequence on the IPOs performance to hypothesize that IPO stocks performance swing (return volatility) is inevitable as far as a real efficient market cannot exist except in a world of utopia. Evidences from the previous studies show that one reason or the other must be achieved or committed to get the IPO stocks marketed at the instance of the issue which subsequently keep influencing the same stocks even in the secondary market over a very long period of time even though at a minimum volatile rate but not completely eliminated. This is what we regard as stocks performance imperfection.

On Exact Determination of Eigen Vectors  [PDF]
Raghuram Prasad Dasaradhi, V. V. Haragopal
Advances in Linear Algebra & Matrix Theory (ALAMT) , 2015, DOI: 10.4236/alamt.2015.52005
Abstract: In this article, we determine the Eigen values and Eigen vectors of a square matrix by a new approach. This considers all the roots with their multiplicities are known, using only the simple matrix multiplication of a vector. This process does not even require matrix inversion.
Mining Corner Points on the Generic Shapes  [PDF]
M. Sarfraz, Z. N. K. Swati
Open Journal of Applied Sciences (OJAppS) , 2013, DOI: 10.4236/ojapps.2013.31B003
Abstract: This paper designs and implements a corner detection algorithm for mining corner points on the generic shapes. The proposed corner detector detects corners by using combination of one rectangle and two ellipses (REE) with different parameter settings in their descriptions. REE combination slides along the boundary of the shape and records number of boundary points in each rectangle and ellipses. REE setup represents both local and global views of the image outline. The proposed technique presents a natural corners detection methodology to detect all true corners accurately. This technique is consistent with human vision system.
Genetic Algorithm Works for Vectoring Image Outlines of Generic Shapes  [PDF]
Misbah Irshad, Muhammad Sarfraz, Malik Zawwar Hussain
Journal of Software Engineering and Applications (JSEA) , 2013, DOI: 10.4236/jsea.2013.67041
Abstract:

This work proposes a scheme which helps digitizing hand printed and electronic planar objects or vectorizing the generic shapes. An evolutionary optimization technique namely Genetic Algorithm (GA) is used to solve the problem of curve fitting with a cubic spline function. GA works well for finding the optimal values of shape parameters in the description of the proposed cubic spline. The underlying scheme comprises of various phases including data of the image outlines, detection of corner points, using GA for optimal values of shape parameters, and fitting curve using cubic spline to the detected corner points.

Prevalence of Gingival Biotype in a Syrian Population and Its Relation to Tooth Shapes: A Cross-Sectional Study  [PDF]
Haydar Barakat, Suleiman Dayoub
Journal of Biomedical Science and Engineering (JBiSE) , 2016, DOI: 10.4236/jbise.2016.93010
Abstract: Background: Gingival biotype is one of the most important factors that impede success in dental treatments; it affects the outcomes of periodontal surgery, and restorative treatments. Researchers classified gingival biotypes into thin biotype and thick biotype. It is crucial to identify tissue biotype before treatment. Aim of Study: To determine the prevalence of gingival biotypes in a Syrian population, in addition, to study the distribution of gingival biotypes according to gender and tooth shape. Material and Methods: This cross sectional study included 500 volunteers (300 males and 200 females) from the patients who had visited the department of periodontology-dental faculty at Damascus University. Gingival thickness was assessed to determine the gingival biotype for the maxillary central incisors using the direct measurement technique (Trans-gingival probing). Shapes of the maxillary incisors were recorded. A written informed consent was taken from each patient. Statistical analysis was done using test k2 p < 0.05. Results: The mean age was 26.8 ± 4.4 years. Thick gingival biotype was detected in 58.4% of the sample and most of patients are men while the prevalence of thin gingival biotype was 41.6% of the sample. It was also observed that patients with thin gingival biotype had triangular tooth shape in 99.5% (p < 0.05). Conclusion: Thick gingival biotype was observed to be more prevalent in a Syrian population than thin biotype. Most Syrian males had thick gingival biotype with square tooth shape while females had thinner biotype and triangular tooth shape.
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