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Boundary Element Analysis of Singular Residual Thermal Stresses in A Fiber-Reinforced Unifirectional Viscoelastic Laminate (섬유가 보강된 단일방향 점탄성 복합재료에 발생하는 특이 잔류 열응력의 경계요소해석)

  • 이상순;박준수
    • Computational Structural Engineering
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    • v.9 no.4
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    • pp.181-187
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    • 1996
  • This paper concerns the singular thermal stresses at the interface corner between the elastic fiber and the viscoelastic matrix of a two-dimensional unidirectional laminate model induced during cooling from cure temperature down to room temperature. Time-domain boundary element method is employed to investigate the nature of residual thermal stresses at the interface. Numerical results show that very large stress gradients are present at the interface corner and such stress singularity might lead to local yielding or fiber-matrix debonding.

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Ferromagnetic Domain Behaviors in Mn doped ZnO Film

  • Soundararajan, Devaraj;Santoyo-Salazar, Jaime;Ko, Jang-Myoun;Kim, Ki-Hyeon
    • Journal of Magnetics
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    • v.16 no.3
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    • pp.216-219
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    • 2011
  • Mn doped ZnO films were prepared on Si (100) substrates using sol-gel method. The prepared films were annealed at $550^{\circ}C$ for decomposition and oxidation of the precursors. XRD analysis revealed the presence of ZnMnO hexagonal wurtzite phase along with the presence of small quantity of $ZnMn_2O_3$ secondary phase and poor crystalline nature. The 2D, 3D views of magnetic domains and domain profiles were obtained using magnetic force microscopy at room temperature. Rectangular shaped domains with an average size of 4.16 nm were observed. Magnetic moment measurement as a function of magnetic field was measured using superconducting quantum interference device (SQUID) magnetometry at room temperature. The result showed the ferromagnetic hysteresis loop with a curie temperature higher than 300 K.

The Role of Lozenge in Drosophila Hematopoiesis

  • Koranteng, Ferdinand;Cha, Nuri;Shin, Mingyu;Shim, Jiwon
    • Molecules and Cells
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    • v.43 no.2
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    • pp.114-120
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    • 2020
  • Drosophila hematopoiesis is comparable to mammalian differentiation of myeloid lineages, and therefore, has been a useful model organism in illustrating the molecular and genetic basis for hematopoiesis. Multiple novel regulators and signals have been uncovered using the tools of Drosophila genetics. A Runt domain protein, lozenge, is one of the first players recognized and closely studied in the hematopoietic lineage specification. Here, we explore the role of lozenge in determination of prohemocytes into a special class of hemocyte, namely the crystal cell, and discuss molecules and signals controlling the lozenge function and its implication in immunity and stress response. Given the highly conserved nature of Runt domain in both invertebrates and vertebrates, studies in Drosophila will enlighten our perspectives on Runx-mediated development and pathologies.

Collaborative Object-Oriented Analysis for Production Control Systems

  • Kim, Chang-Ouk
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.23 no.56
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    • pp.19-34
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    • 2000
  • Impact of business process re-engineering requires the fundamental rethinking of how information systems are analyzed and designed. It is no longer sufficient to establish a monolithic system for fixed business environments. Information systems must be adaptive in nature. This demand is also applied in production domain. Enabling concept for the adaptive information system is reusability. This paper presents a new object-oriented analysis process for creating such reusable software components in production domain, especially for production planning and scheduling. Our process called MeCOMA is based on three meta-models: physical object meta-model, data object meta-model, and activity object meta-model. After the three meta-models are extended independently for a given production system, they are collaboratively integrated on the basis of integration pattern. The main advantages of MeCOMA are (1) to reduce software development time and (2) to consistently build reusable production software components.

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What's Next? Connecting the Past and Future of Business-IT Alignment Research

  • Joshy K. X.;Rahul Thakurta
    • Asia pacific journal of information systems
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    • v.32 no.2
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    • pp.395-434
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    • 2022
  • The importance of Business-IT alignment has been well emphasized, and the topic has been a top management concern for the past four decades. The current business environment demands in response to digitalization have made Business-IT alignment even more challenging. We take on the challenge in this research by presenting a comprehensive review of the domain of Business-IT alignment, based on a conceptual model which we propose, to facilitate future theoretical work. The review brought out multiple representations of the concept of Business-IT alignment and the characterization of its antecedents, nature, and outcomes. Based on the treatment of the domain in the extant literature, we chart out possible areas of future explorations. By doing so, this research lays a foundation for continuing inquiry on Business-IT alignment and facilitating future theoretical work.

Axisymmetric deformation of thick circular plate in microelongated thermoelastic solid

  • Rajneesh Kumar;Aseem Miglani;Ravinder Kumar
    • Coupled systems mechanics
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    • v.13 no.3
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    • pp.231-245
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    • 2024
  • In the present work, a microelogated thermoelastic model based on Lord-Shulman (1967) and Green-Lindsay (1972) theories of thermoelasticity has been constructed. The governing equations for the simulated model are converted into two-dimensional case and made dimensionless for further simplification. Laplace and Hankel transforms followed by eigen value approach has been employed to solve the problem. The use of eigen value approach hasthe advantage of finding the solution of governing equationsin matrix form notations. This approach is straight forward and convenient for numerical computation and avoids the complicate nature of the problem. The components of displacement,stress and temperature distribution are obtained in the transformed domain. Numerical inversion techniques have been used to invert the resulting quantities in the physical domain. Graphical representation of the resulting quantities for describing the effect of microelongation are presented. A special case is also deduced from the present investigation. The problem find application in many engineering problems like thick-walled pressure vesselsuch as a nuclear containment vessel, a cylindricalroller etc.

Application of GNSS Multipath Map by Correction Projection to Position Domain in Urban Canyon (도심지 GNSS 다중경로 오차 지도 적용을 위한 다중경로 보정정보 위치 영역 투영 기법)

  • Yongjun Lee;Heonho Choi;Byungwoon Park
    • Journal of Advanced Navigation Technology
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    • v.28 no.1
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    • pp.155-158
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    • 2024
  • Multipath, a major error source in urban GNSS positioning (global navigation satellite system), pose a challenge due to its site-dependent nature, varying with the user's signal reception environment. In our previous study, we introduced a technique generating GNSS multipath map in urban canyon. However, due to uncertainty in initial GNSS positions, applying multipath maps required generating multiple candidate positions. In this study, we present an efficient method for applying multipath maps by projecting the multipath correction in position domain. This approach effectively applies multipath maps, addressing the challenges posed by urban user position uncertainties.

A magneto-thermo-viscoelastic problem with fractional order strain under GN-II model

  • Deswal, Sunita;Kalkal, Kapil Kumar;Sheoran, Sandeep Singh
    • Structural Engineering and Mechanics
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    • v.63 no.1
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    • pp.89-102
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    • 2017
  • In this work, we present a theoretical framework to study the thermovisco-elastic responses of homogeneous, isotropic and perfectly conducting medium subjected to inclined load. Based on recently developed generalized thermoelasticity theory with fractional order strain, the two-dimensional governing equations are obtained in the context of generalized magnetothermo-viscoelasticity theory without energy dissipation. The Kelvin-Voigt model of linear viscoelasticity is employed to describe the viscoelastic nature of the material. The resulting formulation of the field equations is solved analytically in the Laplace and Fourier transform domain. On the application of inclined load at the surface of half-space, the analytical expressions for the normal displacement, strain, temperature, normal stress and tangential stress are derived in the joint-transformed domain. To restore the fields in physical domain, an appropriate numerical algorithm is used for the inversion of the Laplace and Fourier transforms. Finally, we have demonstrated the effect of magnetic field, viscosity, mechanical relaxation time, fractional order parameter and time on the physical fields in graphical form for copper material. Some special cases have also been deduced from the present investigation.

Directional ARMAX Model-Based Approach for Rotordynamics Identification, Part 2 : Performance Evaluations and Applications (방향 시계열에 의한 회전체 동특성 규명 : (II) 성능 평가 및 응용)

  • 박종포;이종원
    • Journal of KSNVE
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    • v.9 no.1
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    • pp.60-69
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    • 1999
  • In the first paper of this research$^{(1)}$. a new time series method. directional ARMAX (dARMAX) model-based approach. was proposed for rotordynamics identification. The dARMAX processes complex-valued signals, utilizing the complex modal testing theory which enables the separation of the backward and forward modes in the two-sided frequency domain and makes effective modal parameter identification possible. to account for the dynamic characteristics inherent in rotating machinery. In this second part. an evaluation of its performance characteristics based on both simulated and experimental data is presented. Numerical simulations are carried out to show that the method. a complex time series method. successfully implements the complex modal testing in the time domain. and it is superior in nature to the conventional ARMAX and the frequency-domain methods in the estimation of the modal parameters for isotropic and weakly anisotropic rotor systems. Experiments are carried out to demonstrate the applicability and the effectiveness of the dARMAX model-based approach, following the proposed fitting strategy. for the rotordynamics identification.

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Effects of Development Environmental Club Programs for Creative Experiential Learning Activity (창의적 체험활동을 위한 환경동아리 프로그램 개발 및 적용 효과)

  • Lee, Sang-Gyun
    • Journal of the Korean Society of Earth Science Education
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    • v.5 no.1
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    • pp.114-123
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    • 2012
  • This study investigates the effect of environmental club activities of the creative experiential learning activities on the improvement of students' Environmental Literacy and Pro-environmental Behavior. For that purpose, This study divided 24 students at Jinhae U Elementary School into test groups of 12 students and Control groups of 12 students. Test groups participated in the 'GomGomi' environmental Club for sixteen times from March 2011 to December 2011. Conclusions of this study include; First, we found that the environmental club activities is effective to improve the students' environmental Literacy overall. Specifically, the Environmental Club Activities was effective in the sub-catagories of environmental Literacy such as 'rights of nature' and 'eco-crisis'. However, there was no significant change in the sub-category of 'human exemptionalism' Second, we found that the environmental club activities is effective to improve students' pro-environmental behavior overall. Specifically, the environmental club activities was effective in the sub-domains of Pro-environmental Behavior such as 'cognitive domain' and 'affective domain'. However, there was no significant change in the sub-domains of 'behavioral domain'. Summary, the environmental club activities was shown to be effective for improving their environmental literacy and pro-environmental behavior; This study implies that the environmental club activities of the creative experiential learning activities would be a effective tool to help students to improve their environmental literacy and pro-environmental behavior.