• Title/Summary/Keyword: cross sectional shape

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A Cross-sectional Study on the Prevalence of Canine Obesity and Associated Risk Factors in Chuncheon, Kangwon Province (강원도 춘천 지역 개의 비만 유병률과 위험요인에 대한 단면연구)

  • Pak, Son-Il
    • Journal of Veterinary Clinics
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    • v.31 no.1
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    • pp.31-35
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    • 2014
  • As with humans, overweight or obesity is a major health concern in the companion animal population. A cross-sectional questionnaire-based survey of dog owners attending primary small animal veterinary practices from different areas in Chuncheon, Kangwon province, Korea was undertaken to explore the relationships between socioeconomic and other relevant risk factors associated with canine obesity. In addition, the author was to estimate the prevalence of obesity compared to published literatures for dogs. Owners were asked about dog age, neuter status, feeding habits, dog exercise, household income and owner age. The body condition score (BCS) of the dogs was also assessed. Multivariable binary logistic regression was used to assess the association between BCS and potential risk factors controlling for confounding variables, using odds ratios (OR), 95% confidence intervals (CIs). A total of 275 dogs (136 males and 139 females) aged 1-12 years (mean age $5.6{\pm}3.7$ years) were surveyed in 2013. Of these, 46.9% of dogs (n = 129) were classed as an ideal body shape (BCS = 3), 30.9% (n = 85) were overweight (BCS = 4), 8.4% (n = 23) were obese (BCS = 5) and 13.8% (n = 38) were underweight (BCS = 1 or 2). Neutered males and spayed females had the highest prevalence of obesity (43.4% and 33.9%); intact females had the lowest prevalence of obesity (31.6%). In univariable model, risk factors associated with canine obesity are multifactorial and include owner income, owner age, age of dog, neuter status, frequency of feeding per day, frequency of snacks and consultation with veterinarian on dog's weight. In final multivariable logistic regression model, dogs whose owners reported no consultation with veterinarians for weight management were significantly more likely to be obesity than ideal (OR = 7.6, 95% CI, 4.2-13.8; p < 0.0001). This study showed a high prevalence of obesity in domestic companion dogs. Since this was a cross-sectional study with small samples, the association of canine obesity with risk factors warrants more research. To the author's best knowledge, this is the first Korean study on dog body condition and obesity.

An Estimation of RCS through Configuring Element Analysis (형상요소분석을 통한 레이더단면적의 추정)

  • Kwon, T.J.;Shin, Bo-Hyun
    • Journal of the Korea Institute of Military Science and Technology
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    • v.15 no.4
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    • pp.417-423
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    • 2012
  • Radar Cross Section(RCS) is a measure of how detectable an object is with a radar. A larger RCS indicates that an object is more easily detected. Informally, the RCS of an object is the cross-sectional area of a perfectly reflecting sphere that would produce the same amount of reflection strength as the object in question would. In order to estimate RCS of aircraft weapons the external surface is modeled as a collection of simple shape elements. And the overall RCS is estimated as a vector sum of configuring elements' cross-sections which are well known given by analytic formulae. A RCS estimation code is developed for a typical shape of Air-To-Surface bombs and missiles. Size of weapons and location of fins are implemented in the code in addition to the presence of canards. The ability to predict radar return from flying vehicles becomes a critical technology issue in the development of stealth configurations. This simplified method of RCS estimation is known to be fast and accurate enough in an optical region of high frequency incident radio wave.

Shape Reconstruction of Solder Joints on PCB using Iterative Reconstruction Technique (반복복원 기법을 이용한 전자회로기판의 납땜부 형상 복원)

  • 조영빈;권대갑
    • Journal of Institute of Control, Robotics and Systems
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    • v.5 no.3
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    • pp.353-362
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    • 1999
  • This paper presents a shape reconstruction method for automatic inspection of the solder joints on PCBs using X-ray. Shape reconstruction from X-ray radiographic image has been very important since X-ray equipment was used for improving the reliability of inspection result. For this purpose there have been lots of previous works using tomography, which reconstructs the correct shape, laminography or tomosynthesis, which are very fast algorithm. Latter two methods show outstanding performance in cross-sectional image reconstruction of lead type component, but they are also known to show some fatal limitations to some kinds of components such as BGA, because of shadow effect. Although conventional tomography does not have any shadow effect, the shape of PCB prohibits it from being applied to shape reconstruction of solder joints on PCB. This paper shows that tomography using Iterative Reconstruction Technique(IRT) can be applied to this difficult problem without any limitations. This makes conventional radiographic instrument used for shape reconstruction without shadow effect. This means that the new method makes cost down and shadow-free shape reconstruction. To verify the effectiveness of IRT, we develop three dimensional model of BGA solder ball, make projection model to obtain X-ray projection data. and perform a simulation study of shape reconstruction. To compare the performance of IRT with that of conventional laminography or tomosynthesis, reconstruction data are reorganized and error analysis between the original model are also performed.

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Development of a Flexible Incremental Forging Process to Manufacture Asymmetric Shafts (비대칭 축류형 제품의 점진성형공정 개발)

  • Altun A. O.;Lee S. R.;Hong J. T.;Yang D. Y.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2005.10a
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    • pp.95-98
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    • 2005
  • Shafts having asymmetry or odd number of symmetry in the cross-section can not be simply manufactured by conventional incremental radial forging. In order to manufacture such shafts, the new concept of incremental forging with one punch and a flexible fixture is developed by suggesting a flexible fixture, instead of two opposed punches used in radial forging, so that the flexible fixture only supports the workpiece while the punch is moving during forming. A new flexible fixture is designed using the steel shots and vacuum technology. An equilateral triangular cross-section is selected as the sample shape to be manufactured by the proposed manufacturing method. The desired triangular cross-sectional shaft is manufactured with the errors of $3.0\%$.

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Experimental study on laterally restrained steel columns with variable I cross sections

  • Cristutiu, Ionel-Mircea;Nunes, Daniel Luis;Dogariu, Adrian Ioan
    • Steel and Composite Structures
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    • v.13 no.3
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    • pp.225-238
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    • 2012
  • Steel structural elements with web-tapered I cross section, are usually made of welded thin plates. Due to the nonrectangular shape of the element, thin web section may be obtained at the maximum cross section height. The buckling strength is directly influenced by lateral restraining, end support and initial imperfections. If no lateral restraints, or when they are not effective enough, the global behaviour of the members is characterized by the lateral torsional mode and interaction with sectional buckling modes may occur. Actual design codes do not provide a practical design approach for this kind of elements. The paper summarizes an experimental study performed by the authors on a relevant number of elements of this type. The purpose of the work was to evaluate the actual behaviour of the web tapered beam-columns when applying different types of lateral restraints and different web thickness.

Simulation of Fuzzy Shape Control for Cold-Rolled Strip with Randomly Irregular Strip Shape (임의 불량형상을 갖는 냉연판의 퍼지형상제어 시뮬레이션)

  • Jung, Jong-Yeob;Im, Yong-Taek
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.20 no.3
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    • pp.861-871
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    • 1996
  • In this study, a fuzzy control algorithm was developed for the randomly irregular shape of cold-rolled strip. Currently developed fuzzy control algorithm consists of two parts: the first part calculates the changes of work and intermediate roll bender forces based on the symmetric part of the irregular strip shape, and the second part calculates the weighting factors based on the asymmetric part and modifies the pre-determined roll bender forces according to the weighting factors. As a result of this, bender froces applied at the both sides of the cold-rolled strip were different. In order to simulate the continuous shape control. fuzzy controller developed was linked with emulator which was developed based on neural network. The fuzzy controller and emulator developed simulated the cold rolling process until irregular shape converged to a tolerable range in producing uniform cross-sectional strip shape. The results obtained from the simulation were reasonable for various irregular strip shapes.

Process Design of Multi-Pass Shape Rolling for Manufacturing Piston Ring Wire (피스톤 링 제조용 선재의 다단 형상 압연공정 설계)

  • Kim, N.J.;Lee, K.H.;Lim, S.H.;Lee, J.M.;Kim, B.M.
    • Transactions of Materials Processing
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    • v.26 no.1
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    • pp.28-34
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    • 2017
  • Multi-pass shape rolling is performed to produce long products of arbitrary cross-sectional shapes. In the past, the multi-pass shape rolling process has been designed by the trial and error method or the experience of experts based on the empirical approach. Particularly, the design of roll caliber in shape rolling is important to improve product quality and dimensional accuracy. In this paper, the caliber design and pass schedule of multi-pass shape rolling were proposed for manufacturing piston ring wire. In order to design roll caliber, major shape parameter and dimension was determined by analysis of various caliber design. FE-simulation was conducted to verify effectiveness of proposed process design. At first, forming simulation was performed to predict shape of the product. Then, fracture of the wire was evaluated by critical damage value using normalized Cockcroft-Latham criteria. The experiment was carried out and the results are within the allowable tolerance.

Characteristics of the Stress-strain Relationship of Square Sectional Concrete Confined by Hoop Reinforcement with Cross-ties (후프띠철근과 보강띠철근으로 횡구속된 정사각단면 콘크리트의 응력-변형률 특성)

  • Jeong, Hyeok-Chang;Cha, Soo-Won;Kim, Ick-Hyun
    • Journal of the Earthquake Engineering Society of Korea
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    • v.14 no.3
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    • pp.39-48
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    • 2010
  • Improved seismic performances of RC bridges can be attained by sufficient ductilities of piers, which can be obtained by providing sufficient lateral confinements to the plastic hinge regions of piers. The cross sectional shape and the amount of lateral reinforcements are key parameters in the determination of effective confinements. Even though identical amounts of lateral reinforcement are provided, the effective confinement differs due to different spacing, arrangements, hook details and so on. Unlike circular sections in which confinement is exerted by mere hoop reinforcements, cross-ties are arranged in square or rectangular sections to enhance the effective confinements. The stress-strain relationship of confined concrete is varied by how to consider these cross-ties. In this study, the stress-strain relationships of confined concrete with cross-ties are investigated experimentally and their mechanical characteristics are estimated by comparison with other empirical equations.

Free Vibrations of Tapered Beams with Constant Surface Area (일정표면적 변단면 보의 자유진동)

  • Lee, Byoung-Koo;Oh, Sang-Jin;Park, Chang-Eun;Lee, Tae-Eun
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.21 no.1
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    • pp.66-73
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    • 2011
  • This paper deals with free vibrations of the tapered beams with the constant surface area. The surface area of the objective beams are always held constant regardless shape functions of the cross-sectional depth. The shape functions are chosen as the linear and parabolic ones. Ordinary differential equations governing free vibrations of such beams are derived and solved numerically for determining the natural frequencies. In the numerical examples, hinged-hinged, hinged-clamped and clamped-clamped end constraints are considered. As the numerical results, the relationships between non-dimensional frequency parameters and various beam parameters such as section ratio, surface area ratio, end constraint and taper type are reported in tables and figures. Especially, section ratios of the strongest beam are calculated, under which the maximum frequencies are achieved.

Rational B-spline Approximation of Point Data For Reverse Engineering (점 데이타의 Rational B-spline 근사를 통한 역공학)

  • Lee, Hyun-Zic;Ko, Tae-Jo;Kim, Hee-Sool
    • Journal of the Korean Society for Precision Engineering
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    • v.16 no.5 s.98
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    • pp.160-168
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    • 1999
  • This paper describes one method of reverse engineering that machines a free form shape without descriptive model. A portable five-axes 3D CMM was used to digitize point data from physical model. After approximation by rational B-spline curve from digitized point data of a geometric shape, a surface was constructed by the skinning method of the cross-sectional design technique. Since a surface patch was segmented by fifteen part, surface merging was also implemented to assure the surface boundary continuity. Finally, composite surface was transferred to commercial CAD/CAM system through IFES translation in order to machine the modeled geometric shape.

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