• Title/Summary/Keyword: matrix theory

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Introduction to the Indian Buffet Process: Theory and Applications (인도부페 프로세스의 소개: 이론과 응용)

  • Lee, Youngseon;Lee, Kyoungjae;Lee, Kwangmin;Lee, Jaeyong;Seo, Jinwook
    • The Korean Journal of Applied Statistics
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    • v.28 no.2
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    • pp.251-267
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    • 2015
  • The Indian Buffet Process is a stochastic process on equivalence classes of binary matrices having finite rows and infinite columns. The Indian Buffet Process can be imposed as the prior distribution on the binary matrix in an infinite feature model. We describe the derivation of the Indian buffet process from a finite feature model, and briefly explain the relation between the Indian buffet process and the beta process. Using a Gaussian linear model, we describe three algorithms: Gibbs sampling algorithm, Stick-breaking algorithm and variational method, with application for finding features in image data. We also illustrate the use of the Indian Buffet Process in various type of analysis such as dyadic data analysis, network data analysis and independent component analysis.

The effect analysis where beauty care service's quality of perception influences to a value of perception

  • Kim, Sung-Nam;Jung, Hyun-Jin
    • Journal of Fashion Business
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    • v.9 no.6
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    • pp.39-55
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    • 2005
  • This study examines closely the relationship between beauty art service quality and value. And satisfaction and purchase action that they do perceive to customers who have beauty art service company's service use experience. Moreover, this study was achieved purposely to present service raising plan of good quality to beauty art company managers and business employees. First, to investigate the concept of beauty art service quality and special quality was with doctrines that have been presented through a virtue aspect to achieve this study. Moreover, the wave and beauty art service, human service relativity is a let down unlike manufacture enterprise. Further more, beauty art service by complex composition of existence and nonexistence style is sold, and it could be known by having personality consumed at the same time production. The concept of quality about beauty art service and quality that became perceived through virtue study of concept and measurement about value. Therefor, value was deduced, and could deduce measurement, the linear measure that is applied to measure this. Large majority virtue study found is measuring quality of service to 22 articles on PZB's theory, and this study corrects measurement, the linear measure that is applied in Morritt's study that is based in PZB matrix and supplements and attempted measurement to 22 items. The result measurement dimension is consisted of functional quality, technological quality, physical quality dimension. To measure this through virtue study about value that become perceive, could confirm that all expense and beauty art companies which the customer is paid, connect with offering general quality of service. Therefor, through measurement, 2 dimension was deduced by monetary value and the non-monetary value.

The evaluation of aid effectiveness using the input-output analysis: the case of Vietnam (산업연관분석을 활용한 원조의 국가단위 효과 평가 - 한국 유상원조의 베트남 지원효과를 중심으로 -)

  • Park, Bokyeong;An, Jiyoun
    • International Area Studies Review
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    • v.22 no.2
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    • pp.211-218
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    • 2018
  • The evaluation of aid effectiveness at the national level has mostly focused on qualitative evaluation. This paper attempts to quantitatively evaluate EDCF 's support for Vietnam in 1995 ~ 2016 on the economy. First, we compare the strengths and weaknesses of various methodologies that can be used for quantitative assessment: panel analysis based on growth theory, input-output analysis, social account matrix analysis, CGE model, DSGE model, and time series analysis. Using the input-output analysis, we estimate that total output and value added have been generated about $5.9 billion and $1.7 billion in Vietnam, respectively. The increase in income per capita from the support was estimated to have contributed to a 0.21%p reduction in the poverty rate in Vietnam.

Study on the Physical Imaging Characteristics by Using Magnetic Resonance Imaging 1.5T (1.5T 자기공명영상을 이용한 물리적 영상 특성에 대한 연구)

  • Min, Jung-Whan;Jeong, Hoi-Woun;Han, Ji-Hyun;Lee, Si-Nae;Park, Jang-Ho;Kim, Ki-Won;Kim, Hyun-Soo
    • Journal of radiological science and technology
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    • v.42 no.5
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    • pp.329-334
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    • 2019
  • This study was purpose to quantitative evaluation of noise power spectrum(NPS) and studied the quantitative evaluation and characteristics of modulation transfer function(MTF) by obtain the optimal edge image by using Coil in magnetic resonance imaging(MRI) equipment through Fujita theory using edge method. The MRI equipment was used (Tim AVANTO 1.5T, Siemense healthcare system, Germany) and the head matrix coil were 12channels(elements) receive coil. The NPS results of showed the best value of 0.004 based on the T2 Nyquist frequency of $1.0mm^{-1}$, and the MTF results of showed that the T1 and T2 values were generally better than the T1 CE and T1 CE FC values. The characteristics of this study were to explain the characteristic method of image quality evaluation in general. To present the quantitative evaluation process and results in the evaluation of MRI image characteristics in radiology.

Higher-order Spectral Method for Regular and Irregular Wave Simulations

  • Oh, Seunghoon;Jung, Jae-Hwan;Cho, Seok-Kyu
    • Journal of Ocean Engineering and Technology
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    • v.34 no.6
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    • pp.406-418
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    • 2020
  • In this study, a nonlinear wave simulation code is developed using a higher-order spectral (HOS) method. The HOS method is very efficient because it can determine the solution of the boundary value problem using fast Fourier transform (FFT) without matrix operation. Based on the HOS order, the vertical velocity of the free surface boundary was estimated and applied to the nonlinear free surface boundary condition. Time integration was carried out using the fourth order Runge-Kutta method, which is known to be stable for nonlinear free-surface problems. Numerical stability against the aliasing effect was guaranteed by using the zero-padding method. In addition to simulating the initial wave field distribution, a nonlinear adjusted region for wave generation and a damping region for wave absorption were introduced for wave generation simulation. To validate the developed simulation code, the adjusted simulation was carried out and its results were compared to the eighth order Stokes theory. Long-time simulations were carried out on the irregular wave field distribution, and nonlinear wave propagation characteristics were observed from the results of the simulations. Nonlinear adjusted and damping regions were introduced to implement a numerical wave tank that successfully generated nonlinear regular waves. According to the variation in the mean wave steepness, irregular wave simulations were carried out in the numerical wave tank. The simulation results indicated an increase in the nonlinear interaction between the wave components, which was numerically verified as the mean wave steepness. The results of this study demonstrate that the HOS method is an accurate and efficient method for predicting the nonlinear interaction between waves, which increases with wave steepness.

On the mechanics of nanocomposites reinforced by wavy/defected/aggregated nanotubes

  • Heidari, Farshad;Taheri, Keivan;Sheybani, Mehrdad;Janghorban, Maziar;Tounsi, Abdelouahed
    • Steel and Composite Structures
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    • v.38 no.5
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    • pp.533-545
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    • 2021
  • What is desirable in engineering is to bring the engineering model as close to reality as possible while the simplicity of model is also considered. In recent years, several studies have been performed on nanocomposites but some of these studies are somewhat far from reality. For example, in many of these studies, the carbon nanotubes (CNTs) are assumed completely straight, flawless and uniformly distributed throughout the matrix but by studying nanocomposites, we find that this is not the case. In this paper, three steps have been taken to bring the presented models for nanocomposites closer to reality. One is that assuming the straightness of nanotubes is removed and the waviness is considered. Also, the nanotubes are not considered to be pristine and the influence of defect is included in accordance with reality. In addition, the approximation of uniform distribution of nanotubes is ignored and according to experimental observations, the effect of nanotube aggregation is considered. As far as we know, this is the first study on these three topics together in an article. Moreover, we also include the size effects in our models for nanocomposites. To show the accuracy of our models, our results are calibrated with experimental results and compared with theoretical model. For numerical examples, we present the buckling behaviors of nanocomposites including the size effects using nonlocal theory and compare the results of our models with the results of models with above-mentioned approximations.

A Scoping Review of Health-Related Intervention Studies Using Intervention Mapping in South Korea (중재 매핑을 활용한 국내 건강관련 중재연구의 주제범위 고찰)

  • Park, Jiyoung;Cho, Jeonghyun;Im, Mihae;Hwang, Gahui
    • Journal of Korean Public Health Nursing
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    • v.35 no.3
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    • pp.448-468
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    • 2021
  • Objectives: This study aimed to understand the trends and issues of health-related intervention research using Intervention Mapping over the last ten years in South Korea. Intervention Mapping is a representative planning protocol to develop theory-and-evidence-based health promotion programs. Methods: The scoping review method was undertaken, and a total of 20 studies were analyzed using Intervention Mapping six steps. Results: The Korean health-related intervention studies using Intervention Mapping showed low methodological quality. In step 1, only 7 out of 20 studies organized a planning group consisting of various stakeholders. In step 2, about half of the studies did not present a matrix, which is the core essential component of Intervention Mapping. In step 5, only 1 out of 20 studies presented program adopters and maintainers. In step 6, most studies described effect evaluation relatively, but only one study mentioned process evaluation. Conclusions: In order to develop sustainable and cost-effective programs, systematic planning using Intervention Mapping is required from the research planning stage. In addition, a concrete and realistic plan needs to be established for the development of programs and adoption, dissemination and maintenance of programs.

Development of Creative Problem-Solving Activities for Integrating Mathematics and Information Science: Focusing on the Hat Game for Mathematically Gifted Students (수학 정보과학 융합을 위한 창의적 문제해결 활동 개발: 영재 학생을 대상으로 한 모자 게임을 중심으로)

  • Seo, Jiyoung;Youn, Sang-Gyun
    • Communications of Mathematical Education
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    • v.36 no.3
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    • pp.439-467
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    • 2022
  • The future society requires not only knowledge but also various competencies, including creativity, cooperative spirit and integrated thinking. This research develops a program for integrating mathematics and information science to enhance important mathematical competencies such as problem-solving and communication. This program does not require much prior knowledge, can be motivated using everyday language and easy-to-access tools, and is based on creative problem-solving activities with multilateral cooperation. The usefulness and rigor of mathematics are emphasized as the number of participants increases in the activities, and theoretical principles stem from the matrix theory over finite fields. Moreover, the activity highlights a connection with error-correcting codes, an important topic in information science. We expect that the real-world contexts of this program contribute to enhancing mathematical communication competence and providing an opportunity to experience the values of mathematics and that this program to be accessible to teachers since coding is not included.

Gamma ray attenuation behaviors and mechanism of boron rich slag/epoxy resin shielding composites

  • Mengge Dong;Suying Zhou ;He Yang ;Xiangxin Xue
    • Nuclear Engineering and Technology
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    • v.55 no.7
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    • pp.2613-2620
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    • 2023
  • Excellent thermal neutron absorption performance of boron expands the potential use of boron rich slag to prepare epoxy resin matrix nuclear shielding composites. However, shielding attenuation behaviors and mechanism of the composites against gamma rays are unclear. Based on the radiation protection theory, Phy-X/PSD, XCOM, and 60Co gamma ray source were integrated to obtain the shielding parameters of boron rich slag/epoxy resin composites at 0.015-15 MeV, which include mass attenuation coefficient (µt), linear attenuation coefficient (µ), half value thickness layer (HVL), electron density (Neff), effective atomic number (Zeff), exposure buildup factor (EBF) and exposure absorption buildup factor (EABF).µt, µ, HVL, Neff, Zeff, EBF and EABF are 0.02-7 cm2/g, 0.04-17 cm-1, 0.045-20 cm, 5-14, 3 × 1023-8 × 1023 electron/g, 0-2000, and 0-3500. Shielding performance is BS4, BS3, BS3, BS1 in descending order, but worse than ordinary concrete. µ and HVL of BS1-BS4 for 60Co gamma ray is 0.095-0.110 cm-1 and 6.3-7.2 cm. Shielding mechanism is main interactions for attenuation gamma ray by BS1-BS4 are elements with higher content or higher atomic number via Photoelectric Absorption at low energy range, and elements with higher content via Compton Scattering and Pair Production in Nuclear Field at middle and higher energy range.

Porosity-dependent vibration investigation of functionally graded carbon nanotube-reinforced composite beam

  • Abdulmajeed M. Alsubaie;Ibrahim Alfaqih;Mohammed A. Al-Osta;Abdelouahed Tounsi;Abdelbaki Chikh;Ismail M. Mudhaffar;Saeed Tahir
    • Computers and Concrete
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    • v.32 no.1
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    • pp.75-85
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    • 2023
  • This work utilizes simplified higher-order shear deformation beam theory (HSDBT) to investigate the vibration response for functionally graded carbon nanotube-reinforced composite (CNTRC) beam. Novel to this work, single-walled carbon nanotubes (SWCNTs) are distributed and aligned in a matrix of polymer throughout the beam, resting on a viscoelastic foundation. Four un-similar patterns of reinforcement distribution functions are investigated for the CNTRC beam. Porosity is another consideration taken into account due to its significant effect on functionally graded materials (FGMs) properties. Three types of uneven porosity distributions are studied in this study. The damping coefficient and Winkler's and Pasternak's parameters are considered in investigating the viscosity effect on the foundation. Moreover, the impact of different parameters on the vibration of the CNTRC beam supported by a viscoelastic foundation is discussed. A comparison to other works is made to validate numerical results in addition to analytical discussions. The findings indicate that incorporating a damping coefficient can improve the vibration performance, especially when the spring constant factors are raised. Additionally, it has been noted that the fundamental frequency of a beam increases as the porosity coefficient increases, indicating that porosity may have a significant impact on the vibrational characteristics of beams.