• Title/Summary/Keyword: monotonic functions

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Formulation Method of a Solid-To-Beam Transitional Finite Element (연속체-보 천이 유한요소의 구성)

  • Park, Woo-Jin;Lim, Jang-Keun
    • Proceedings of the KSME Conference
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    • 2000.04a
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    • pp.351-356
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    • 2000
  • Various transition elements are generally used for the effective analysis of a complicated mechanical structure. In this paper, a solid-to-beam transition finite element which connects a continuum element and a $c^1-continuity$ beam element each other is proposed. The shape functions of the transition finite elements, which a 8-noded hexahedral solid element fur 3D analysis and a 4-noded quadrilateral plane element fur 2D analysis are connected to a Euler's beam element, are explicitely formulated. In order to show the effectiveness and convergence characteristics of the proposed transition elements. numerical tests are performed for various examples and their results are compared with those obtained by other methods. As the result of this study. following conclusions are obtained: (1)The proposed transition finite elements show the monotonic convergence characteristics because of having used the compatible displacement folds. (2)As being used the transition element in the finite element analysis, the finite element modelings are more convenient and the analysis results are more accurate because of the formulation characteristies of the Euler's beam element.

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Implementation of Operating Software for Small Multi-Jointed Robots (소형 다관절로봇을 위한 운용 소프트웨어 구현)

  • Son, Hyun-Seung;Kim, Woo-Yeol;Kim, Young-Chul
    • Journal of Institute of Control, Robotics and Systems
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    • v.15 no.9
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    • pp.946-951
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    • 2009
  • The small multi-jointed robots for most education are developed with the way of firmware. But the firmware may be very difficult to develop as gradually increasing throughputs and control routines. Due to limit of firmware we try to use on RTOS, but hard to adapt on the small multi-jointed robots. It would be hard to install RTOS into the small multi-jointed robots because of the size capacity of RTOS, and lack of libraries for control of the particular hardware. Moreover, even its RTOS with many functions causes its to make overheads scheduling, TCB (Task Control Block), and task states. Also to keep maintenance of RTOS, it is composed of components for the whole structure of my proposed RTOS. Additionally, We provided with libraries of servo motor and sensor control and developed RMS (Rate Montonic scheduler) to handle tasks on real time and reduce overheads. Therefore, It is possible to work the fixed priority and task preemptive way. We show one example of the multi-jointed robot installed with my proposed RTOS, which shows to obstacle avoidance and climbing up the slope.

Analytical p-version finite elements and application in analyses of structural collision protection

  • Zhu, B.;Chen, Y.M.;Leung, A.Y.T.
    • Structural Engineering and Mechanics
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    • v.23 no.5
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    • pp.487-504
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    • 2006
  • Several new versatile two-dimensional p-version finite elements are developed. The element matrices are integrated analytically to guarantee the accuracy and monotonic convergence of the predicted solutions of the proposed p-version elements. The analysis results show that the convergence rate of the present elements is very fast with respect to the number of additional Fourier or polynomial terms in shape functions, and their solutions are much more accurate than those of the linear finite elements for the same number of degrees of freedom. Additionally, the new p-version plate elements without the reduced integration can overcome the shear locking problem over the conventional h-version elements. Using the proposed p-version elements with fast convergent characteristic, the elasto-plastic impact of the structure attached with the absorber is simulated. Good agreement between the simulated and experimental results verifies the present p-version finite elements for the analyses of structural dynamic responses and the structural elasto-plastic impact. Further, using the elasto-plastic impact model and the p-version finite element method, the absorber of the T structure on the Qiantang River is designed for its collision protection.

An Edge Detector by Using Perfect Sharpening of Ramps (램프의 완전 선명화를 이용한 에지 검출기)

  • Lee, Jong-Gu;Yoo, Cheol-Jung;Chang, Ok-Bae
    • Journal of KIISE:Software and Applications
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    • v.34 no.11
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    • pp.961-970
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    • 2007
  • Since the usual conventional edge detectors employ the local differential derivatives, the detected edges are not uniform in their widths or some edges are missed out of the detection on magnified images. We employ a mapping from the exactly monotonic intensity distributions of ramp edges to the simple step functions of intensity, which is referred to as perfect sharpening map of ramp edges. This map is based on the non-local feature of intensity distribution and used to introduce a modified differentiation, in terms of which we can construct an efficient edge detector adaptive to the variation of edge width. By adopting the operator MADD in this paper, we developed an edge detector that works stably against the magnification of image or the variation of edge width. It is shown by comparing to the conventional algorithms that the proposed one is very excellent.

Bayesian Computation for Superposition of MUSA-OKUMOTO and ERLANG(2) processes (MUSA-OKUMOTO와 ERLANG(2)의 중첩과정에 대한 베이지안 계산 연구)

  • 최기헌;김희철
    • The Korean Journal of Applied Statistics
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    • v.11 no.2
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    • pp.377-387
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    • 1998
  • A Markov Chain Monte Carlo method with data augmentation is developed to compute the features of the posterior distribution. For each observed failure epoch, we introduced latent variables that indicates with component of the Superposition model. This data augmentation approach facilitates specification of the transitional measure in the Markov Chain. Metropolis algorithms along with Gibbs steps are proposed to preform the Bayesian inference of such models. for model determination, we explored the Pre-quential conditional predictive Ordinate(PCPO) criterion that selects the best model with the largest posterior likelihood among models using all possible subsets of the component intensity functions. To relax the monotonic intensity function assumptions, we consider in this paper Superposition of Musa-Okumoto and Erlang(2) models. A numerical example with simulated dataset is given.

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Free Vibration Analysis of a Degenerated Timoshenko Beam Including the Effect of Shear Deformation and Rotatory Inertia (전단변형(剪斷變形)과 회전관성(回轉慣性)을 고려(考慮)한 Timoshenko 보의 자유진동(自由振動) 해석(解析))

  • Byun, Dong Kyun;Shin, Young Shik;Jang, Jong Tak
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.3 no.4
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    • pp.109-122
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    • 1983
  • An accurate thick beam element (TB4) which includes the effects of the shear deformation and rotatory inertia has been degenerated from the three dimensional continuum by employing the Timoshenko beam assumptions. The proposed TB4 element has four nodes and two degrees of freedom at each node, totally eight degrees of freedom. The transverse deflection W and plane rotation ${\theta}$ with the cubic interpolation functions are selected as nodal variables. The element characteristics are formulated by discretizing the beam equations of motion, using the Galerkin weighted residual method, and are numerically integrated by the reduced shear integration technique, using the three-point Gauss quadrature with the various shear coefficients. Several numerical examples are analyzed to demonstrate the accuracy and the monotonic convergence behavior of the proposed TB4 beam element. The result indicates that the TB4 element shows the more excellent performance and the monotonic convergence behavior than the other existing Timoshenko beam type elements for the whole range of the beam aspect ratios, in both static and free vibration analyses.

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GORank: Semantic Similarity Search for Gene Products using Gene Ontology (GORank: Gene Ontology를 이용한 유전자 산물의 의미적 유사성 검색)

  • Kim, Ki-Sung;Yoo, Sang-Won;Kim, Hyoung-Joo
    • Journal of KIISE:Databases
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    • v.33 no.7
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    • pp.682-692
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    • 2006
  • Searching for gene products which have similar biological functions are crucial for bioinformatics. Modern day biological databases provide the functional description of gene products using Gene Ontology(GO). In this paper, we propose a technique for semantic similarity search for gene products using the GO annotation information. For this purpose, an information-theoretic measure for semantic similarity between gene products is defined. And an algorithm for semantic similarity search using this measure is proposed. We adapt Fagin's Threshold Algorithm to process the semantic similarity query as follows. First, we redefine the threshold for our measure. This is because our similarity function is not monotonic. Then cluster-skipping and the access ordering of the inverted index lists are proposed to reduce the number of disk accesses. Experiments with real GO and annotation data show that GORank is efficient and scalable.

A component method model for blind-bolts with headed anchors in tension

  • Pitrakkos, Theodoros;Tizani, Walid
    • Steel and Composite Structures
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    • v.18 no.5
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    • pp.1305-1330
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    • 2015
  • The successful application of the component-based approach - widely used to model structural joints - requires knowledge of the mechanical properties of the constitutive joint components, including an appropriate assembly procedure to derive the joint properties. This paper presents a component-method model for a structural joint component that is located in the tension zone of blind-bolted connections to concrete-filled tubular steel profiles. The model relates to the response of blind-bolts with headed anchors under monotonic loading, and the blind-bolt is termed the "Extended Hollo-bolt". Experimental data is used to develop the model, with the data being collected in a manner such that constitutive models were characterised for the principal elements which contribute to the global deformability of the connector. The model, based on a system of spring elements, incorporates pre-load and deformation from various parts of the blind-bolt: (i) the internal bolt elongation; (ii) the connector's expanding sleeves element; and (iii) the connector's mechanical anchorage element. The characteristics of these elements are determined on the basis of piecewise functions, accounting for basic geometrical and mechanical properties such as the strength of the concrete applied to the tube, the connection clamping length, and the size and class of the blind-bolt's internal bolt. An assembly process is then detailed to establish the model for the elastic and inelastic behaviour of the component. Comparisons of model predictions with experimental data show that the proposed model can predict with sufficient accuracy the response of the component. The model furthers the development of a full and detailed design method for an original connection technology.

A TOPSIS-based Approach to Evaluating the University's Department Homepages for Operational Management Purposes (TOPSIS 기반 대학 학과 홈페이지 운영관리 평가방안)

  • Jeong, Gi-Ho
    • Journal of Convergence for Information Technology
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    • v.9 no.9
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    • pp.126-132
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    • 2019
  • This study presents a TOPSIS-based application for the evaluation of administrative purposes on the website of university's departments. As the school age population decreases, the homepage of the university's departments also has important promotional means. However, most of them are not well managed until a full renewal. This is because the investment is difficult compared to strategic importance. Therefore, this paper tries to show its usefulness by applying a partially modified TOPSIS for management purposes, in consideration of the practicality. TOPSIS is appropriate for target management as a conceptual reason to prioritize based on the distance from the ideal target for each criterion. Also, in the case of monotonic functions of the evaluation criteria used, the same results can be obtained by reducing the amount of calculations through a partially modified procedure as presented in this study.