• 제목/요약/키워드: computational mathematics

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The Effect of Physical Computing Education to Improve the Convergence Capability of Secondary Mathematics-Science Gifted Students (중등 수학과학 영재를 위한 피지컬컴퓨팅 교육이 융합적 역량 향상에 미치는 영향)

  • Kim, Jihyun;Kim, Taeyoung
    • The Journal of Korean Association of Computer Education
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    • 제19권2호
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    • pp.87-98
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    • 2016
  • Our study is composed of Arduino robot assembly, board connecting and collaborative programming learning, and it is to evaluate their effect on improving secondary mathematics-science gifted students' convergence capability. Research results show that interpersonal skills, information-scientific creativity and integrative thinking disposition are improved. Further, by analyzing the relationship between the sub-elements of each thinking element, persistence and imagination for solving problems, interest of scientific information, openness, sense of adventure, a logical attitude, communication, productive skepticism and so on are extracted as important factors in convergence learning. Thus, as the result of our study, we know that gifted students conducted various thinking activities in their learning process to solve the problem, and it can be seen that convergence competencies are also improved significantly.

SYMMETRIC SOLUTIONS FOR A FOURTH-ORDER MULTI-POINT BOUNDARY VALUE PROBLEMS WITH ONE-DIMENSIONAL $p$-LAPLACIAN AT RESONANCE

  • Yang, Aijun;Wang, Helin
    • Journal of applied mathematics & informatics
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    • 제30권1_2호
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    • pp.161-171
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    • 2012
  • We consider the fourth-order differential equation with one-dimensional $p$-Laplacian (${\phi}_p(x^{\prime\prime}(t)))^{\prime\prime}=f(t,x(t),x^{\prime}(t),x^{\prime\prime}(t)$) a.e. $t{\in}[0,1]$, subject to the boundary conditions $x^{\prime\prime}}(0)=0$, $({\phi}_p(x^{\prime\prime}(t)))^{\prime}{\mid}_{t=0}=0$, $x(0)={\sum}_{i=1}^n{\mu}_ix({\xi}_i)$, $x(t)=x(1-t)$, $t{\in}[0,1]$, where ${\phi}_p(s)={\mid}s{\mid}^{p-2}s$, $p$ > 1, 0 < ${\xi}_1$ < ${\xi}_2$ < ${\cdots}$ < ${\xi}_n$ < $\frac{1}{2}$, ${\mu}_i{\in}\mathbb{R}$, $i=1$, 2, ${\cdots}$, $n$, ${\sum}_{i=1}^n{\mu}_i=1$ and $f:[0,1]{\times}\mathbb{R}^3{\rightarrow}\mathbb{R}$ is a $L^1$-Carath$\acute{e}$odory function with $f(t,u,v,w)=f(1-t,u,-v,w)$ for $(t,u,v,w){\in}[0,1]{\times}\mathbb{R}^3$. We obtain the existence of at least one nonconstant symmetric solution by applying an extension of Mawhin's continuation theorem due to Ge. Furthermore, an example is given to illustrate the results.

Explicit Matrix Expressions of Progressive Iterative Approximation

  • Chen, Jie;Wang, Guo-Jin
    • International Journal of CAD/CAM
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    • 제13권1호
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    • pp.1-11
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    • 2013
  • Just by adjusting the control points iteratively, progressive iterative approximation (PIA) presents an intuitive and straightforward scheme such that the resulting limit curve (surface) can interpolate the original data points. In order to obtain more flexibility, adjusting only a subset of the control points, a new method called local progressive iterative approximation (LPIA) has also been proposed. But to this day, there are two problems about PIA and LPIA: (1) Only an approximation process is discussed, but the accurate convergence curves (surfaces) are not given. (2) In order to obtain an interpolating curve (surface) with high accuracy, recursion computations are needed time after time, which result in a large workload. To overcome these limitations, this paper gives an explicit matrix expression of the control points of the limit curve (surface) by the PIA or LPIA method, and proves that the column vector consisting of the control points of the PIA's limit curve (or surface) can be obtained by multiplying the column vector consisting of the original data points on the left by the inverse matrix of the collocation matrix (or the Kronecker product of the collocation matrices in two direction) of the blending basis at the parametric values chosen by the original data points. Analogously, the control points of the LPIA's limit curve (or surface) can also be calculated by one-step. Furthermore, the $G^1$ joining conditions between two adjacent limit curves obtained from two neighboring data points sets are derived. Finally, a simple LPIA method is given to make the given tangential conditions at the endpoints can be satisfied by the limit curve.

COMPARISONS OF PARALLEL PRECONDITIONERS FOR THE COMPUTATION OF SMALLEST GENERALIZED EIGENVALUE

  • Ma, Sang-Back;Jang, Ho-Jong;Cho, Jae-Young
    • Journal of applied mathematics & informatics
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    • 제11권1_2호
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    • pp.305-316
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    • 2003
  • Recently, an iterative algorithm for finding the interior eigenvalues of a definite matrix by CG-type method has been proposed. This method compares to the inverse power method. The given matrices A, and B are assumed to be large and sparse, and SPD( Symmetric Positive Definite) The CG scheme for the optimization of the Rayleigh quotient has been proven a very attractive and promising technique for large sparse eigenproblems for smallest eigenvalue. Also, it is very amenable to parallel computations, like the CG method for the linear systems. A proper choice of the preconditioner significantly improves the convergence of the CG scheme. But for parallel computations we need to find an efficient parallel preconditioner. Our candidates we ILU(0) in the wave-front order, ILU(0) in the multi-coloring order, Point-SSOR(Symmetric Successive Overrelaxation), and Multi-Color Block SSOR preconditioner. Wavefront order is a simple way to increase parallelism in the natural order, and Multi-coloring realizes a parallelism of order(N), where N is the order of the matrix. Another choice is the Multi-Color Block SSOR(Symmetric Successive OverRelaxation) preconditioning. Block SSOR is a symmetric preconditioner which is expected to minimize the interprocessor communication due to the blocking. We implemented the results on the CRAY-T3E with 128 nodes. The MPI (Message Passing Interface) library was adopted for the interprocessor communications. The test problem was drawn from the discretizations of partial differential equations by finite difference methods. The results show that for small number of processors Multi-Color ILU(0) has the best performance, while for large number of processors Multi-Color Block SSOR performs the best.

Model selection via Bayesian information criterion for divide-and-conquer penalized quantile regression (베이즈 정보 기준을 활용한 분할-정복 벌점화 분위수 회귀)

  • Kang, Jongkyeong;Han, Seokwon;Bang, Sungwan
    • The Korean Journal of Applied Statistics
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    • 제35권2호
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    • pp.217-227
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    • 2022
  • Quantile regression is widely used in many fields based on the advantage of providing an efficient tool for examining complex information latent in variables. However, modern large-scale and high-dimensional data makes it very difficult to estimate the quantile regression model due to limitations in terms of computation time and storage space. Divide-and-conquer is a technique that divide the entire data into several sub-datasets that are easy to calculate and then reconstruct the estimates of the entire data using only the summary statistics in each sub-datasets. In this paper, we studied on a variable selection method using Bayes information criteria by applying the divide-and-conquer technique to the penalized quantile regression. When the number of sub-datasets is properly selected, the proposed method is efficient in terms of computational speed, providing consistent results in terms of variable selection as long as classical quantile regression estimates calculated with the entire data. The advantages of the proposed method were confirmed through simulation data and real data analysis.

Exploration of the educational possibilities of one-stroke drawing problems of complex figure using programming (프로그래밍을 이용한 복잡한 도형의 한붓그리기 문제의 교육적 가능성 탐색 )

  • Cheong, Yong Wook
    • Communications of Mathematical Education
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    • 제38권2호
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    • pp.247-261
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    • 2024
  • This study propose the educational potential of an activity that solves the task of one-stroke drawing of complex figures using a drag-and-drop type educational programming language such as Scratch. The problem of determining whether a given shape is capable of one-stroke drawing is a separate problem from actually finding the path of one-stroke drawing and implementing it through programming. In particular, finding a path that allows one-stroke drawing of complex shapes with regularity and implementing it through programming requires problem-solving capabilities based on the convergence of various mathematical knowledge. Accordingly, in this study, problems related to one-stroke drawing concerning polygon-related shapes, tessellation-related shapes, and fractal shapes were presented, and the results of one-stroke drawing programming of the shapes were exemplified. In addition, the mathematical knowledge and computational thinking elements necessary for the solution of the illustrated problem were analyzed. This study is significant as a new example of the mathematics education that combines mathematics and information.

A Privacy-Preserving Health Data Aggregation Scheme

  • Liu, Yining;Liu, Gao;Cheng, Chi;Xia, Zhe;Shen, Jian
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제10권8호
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    • pp.3852-3864
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    • 2016
  • Patients' health data is very sensitive and the access to individual's health data should be strictly restricted. However, many data consumers may need to use the aggregated health data. For example, the insurance companies needs to use this data to setup the premium level for health insurances. Therefore, privacy-preserving data aggregation solutions for health data have both theoretical importance and application potentials. In this paper, we propose a privacy-preserving health data aggregation scheme using differential privacy. In our scheme, patients' health data are aggregated by the local healthcare center before it is used by data comsumers, and this prevents individual's data from being leaked. Moreover, compared with the existing schemes in the literature, our work enjoys two additional benefits: 1) it not only resists many well known attacks in the open wireless networks, but also achieves the resilience against the human-factor-aware differential aggregation attack; 2) no trusted third party is employed in our proposed scheme, hence it achieves the robustness property and it does not suffer the single point failure problem.

Penalized quantile regression tree (벌점화 분위수 회귀나무모형에 대한 연구)

  • Kim, Jaeoh;Cho, HyungJun;Bang, Sungwan
    • The Korean Journal of Applied Statistics
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    • 제29권7호
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    • pp.1361-1371
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    • 2016
  • Quantile regression provides a variety of useful statistical information to examine how covariates influence the conditional quantile functions of a response variable. However, traditional quantile regression (which assume a linear model) is not appropriate when the relationship between the response and the covariates is a nonlinear. It is also necessary to conduct variable selection for high dimensional data or strongly correlated covariates. In this paper, we propose a penalized quantile regression tree model. The split rule of the proposed method is based on residual analysis, which has a negligible bias to select a split variable and reasonable computational cost. A simulation study and real data analysis are presented to demonstrate the satisfactory performance and usefulness of the proposed method.

Effective Inverse Matrix Transformation Method for Haptic Volume Rendering (햅틱 볼륨 렌더링을 위한 효과적인 역행렬 계산법)

  • Kim, Nam-Oh;Min, Wan-Ki;Jung, Won-Tae;Kim, Young-Dong
    • Proceedings of the KIEE Conference
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    • 대한전기학회 2007년도 학술대회 논문집 전문대학교육위원
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    • pp.183-186
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    • 2007
  • Realistic deformation of computer simulated anatomical structures is computationally intensive. As a result, simple methodologies not based in continuum mechanics have been employed for achieving real time deformation of virtual reality. Since the graphical interpolations and simple spring models commonly used in these simulations are not based on the biomechanical properties of tissue structures, these "quick and dirty"methods typically do not accurately represent the complex deformations and force-feedback interactions that can take place during surgery. Finite Element(FE) analysis is widely regarded as the most appropriate alternative to these methods. However, because of the highly computational nature of the FE method, its direct application to real time force feedback and visualization of tissue deformation has not been practical for most simulations. If the mathematics are optimized through pre-processing to yield only the information essential to the simulation task run-time computation requirements can be drastically reduced. To apply the FEM, We examined a various in verse matrix method and a deformed material model is produced and then the graphic deformation with this model is able to force. As our simulation program is reduced by the real-time calculation and simplification because the purpose of this system is to transact in the real time.

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CoReHA: conductivity reconstructor using harmonic algorithms for magnetic resonance electrical impedance tomography (MREIT)

  • Jeon, Ki-Wan;Lee, Chang-Ock;Kim, Hyung-Joong;Woo, Eung-Je;Seo, Jin-Keun
    • Journal of Biomedical Engineering Research
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    • 제30권4호
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    • pp.279-287
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    • 2009
  • Magnetic resonance electrical impedance tomography (MREIT) is a new medical imaging modality providing cross-sectional images of a conductivity distribution inside an electrically conducting object. MREIT has rapidly progressed in its theory, algorithm and experimental technique and now reached the stage of in vivo animal and human experiments. Conductivity image reconstructions in MREIT require various steps of carefully implemented numerical computations. To facilitate MREIT research, there is a pressing need for an MREIT software package with an efficient user interface. In this paper, we present an example of such a software, called CoReHA which stands for conductivity reconstructor using harmonic algorithms. It offers various computational tools including preprocessing of MREIT data, identification of boundary geometry, electrode modeling, meshing and implementation of the finite element method. Conductivity image reconstruction methods based on the harmonic $B_z$ algorithm are used to produce cross-sectional conductivity images. After summarizing basics of MREIT theory and experimental method, we describe technical details of each data processing task for conductivity image reconstructions. We pay attention to pitfalls and cautions in their numerical implementations. The presented software will be useful to researchers in the field of MREIT for simulation as well as experimental studies.