• Title/Summary/Keyword: size-dependent model

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Factors Influencing the Choices of Accounting Policies in Small and Medium Enterprises in Vietnam

  • PHAM, Cuong Duc;PHI, Trong Van
    • The Journal of Asian Finance, Economics and Business
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    • v.7 no.10
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    • pp.687-696
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    • 2020
  • Accounting policies are principles and practices by which an entity uses to recognize, measure and report economic transactions. Improper application of accounting policies can lead to misrepresentation of firms' financial position and performance which consequently results in incorrect accounting information to the users. This paper aims to investigate the factors influencing the choices of accounting policies in small and medium enterprises (SMEs) in Vietnam by reviewing relevant literature to build a research model. The research model comprises of one dependent variable that is income-decreasing accounting procedures and six independent variables namely the firm size, financial leverage, incentives, auditor, accountants, and tax policies. After this, the authors collected primary data from more than 200 questionnaires sent to directors and chief accountants of the SMEs for the period 2018 to 2019. We then used Ordinary Least Squares regression method (OLS) to analyze the data. The results showed that four factors influenced selection of accounting policies in which auditors are associated with income-increasing accounting policies; and there are three factors associated with income-decreasing accounting policies which are, company size, tax and accountant. Especially, the research results indicate that company size has a significant influence on the selection of accounting policies in the SMEs. Based on the results, we propose instructive suggestions for regulators and lawmakers improve choices of accounting policies in the SMEs.

Finite Element Analysis of Micro Forming Process by Crystal Plasticity (결정소성학에 의한 미세 성형공정의 유한요소해석)

  • Kim H. K.;Oh S. I.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2001.05a
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    • pp.209-212
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    • 2001
  • It is known that the mim forming processes show somewhat different phenomena compared with the conventional metal forming processes, namely, the size effect, enhanced friction effect and etc. Such typical phenomena, however, are not predicted by the conventional finite element analysis, which has been an efficient numerical tool to predict the metal forming processes. It is due to the fact that the constitutive relations used does not describe the microstructural characteristics of the materials. In the present investigation, the finite element formulation using the rate-dependent rigid plastic crystal plasticity model of the face-centered cubic materials is conducted to predict the micro mechanical behaviors during the mim forming processes. The finite element analysis, however, provides mesh-dependent solutions for the intragranular deformations. Therefore, the couple stress energy is additionally introduced into the variational principle and formulated within the framework of the rigid plastic finite element method to obtain mesh-independent solutions. Micro deformations of single crystal and bicrystal with various orientations are calculated to show the potential of the developed formulation.

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Semi-analytical vibration analysis of functionally graded size-dependent nanobeams with various boundary conditions

  • Ebrahimi, Farzad;Salari, Erfan
    • Smart Structures and Systems
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    • v.19 no.3
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    • pp.243-257
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    • 2017
  • In this paper, free vibration of functionally graded (FG) size-dependent nanobeams is studied within the framework of nonlocal Timoshenko beam model. It is assumed that material properties of the FG nanobeam, vary continuously through the thickness according to a power-law form. The small scale effect is taken into consideration based on nonlocal elasticity theory of Eringen. The non-classical governing differential equations of motion are derived through Hamilton's principle and they are solved utilizing both Navier-based analytical method and an efficient and semi-analytical technique called differential transformation method (DTM). Various types of boundary conditions such as simply-supported, clamped-clamped, clamped-simply and clamped-free are assumed for edge supports. The good agreement between the presented DTM and analytical results of this article and those available in the literature validated the presented approach. It is demonstrated that the DTM has high precision and computational efficiency in the vibration analysis of FG nanobeams. The obtained results show the significance of the material graduation, nonlocal effect, slenderness ratio and boundary conditions on the vibration characteristics of FG nanobeams.

A framework for geometrically non-linear gradient extended crystal plasticity coupled to heat conduction and damage

  • Ekh, Magnus;Bargmann, Swantje
    • Multiscale and Multiphysics Mechanics
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    • v.1 no.2
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    • pp.171-188
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    • 2016
  • Gradient enhanced theories of crystal plasticity enjoy great research interest. The focus of this work is on thermodynamically consistent modeling of grain size dependent hardening effects. In this contribution, we develop a model framework for damage coupled to gradient enhanced crystal thermoplasticity. The damage initiation is directly linked to the accumulated plastic slip. The theoretical setting is that of finite strains. Numerical results on single-crystalline metal showing the development of damage conclude the paper.

Thermo-Mechanica1 Stress Analyses of Part with Coated Layer under Contact Load Using Partial Model (부분 모델을 이용한 접촉하중을 받는 코팅층이 있는 부재의 열적/기계적 응력해석)

  • 권영두;김석삼;신세현;추상우
    • Tribology and Lubricants
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    • v.18 no.3
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    • pp.228-234
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    • 2002
  • Generally, space structures are subjected to severe situations, such as, sublimation, strong evaporation of lubricants, thermal stresses, high temperature gradients, irradiation, impacts by microscopic meteorites, and other factors. Recent]y, various kinds of coatings are applied to the parts under heavy contact stresses, in order to insure long wear-free lives and/or reduce friction coefficients. In space structures, molybdenum disulfide is using frequently. Moreover TiN, Al$_2$O$_3$, PTFE(Poly Tetra Fluor Ethylene) are introduced recently for space structure. In this part we are going to apply the partial model method, developed in reference[11] to analyze part with coated layer. In referencer[l1], we compute the reasonable size of partial model and aspect ratio. Using these data, we analyze the structures coated with TiN, Al$_2$O$_3$, PTFE under contact load, temperature and crack model . Beside, we consider the stress analysis under time dependent load and transient thermal effect.

Unseen Model Prediction using an Optimal Decision Tree (Optimal Decision Tree를 이용한 Unseen Model 추정방법)

  • Kim Sungtak;Kim Hoi-Rin
    • MALSORI
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    • no.45
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    • pp.117-126
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    • 2003
  • Decision tree-based state tying has been proposed in recent years as the most popular approach for clustering the states of context-dependent hidden Markov model-based speech recognition. The aims of state tying is to reduce the number of free parameters and predict state probability distributions of unseen models. But, when doing state tying, the size of a decision tree is very important for word independent recognition. In this paper, we try to construct optimized decision tree based on the average of feature vectors in state pool and the number of seen modes. We observed that the proposed optimal decision tree is effective in predicting the state probability distribution of unseen models.

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A Study on the Development of One-Dimensional Time - Dependent Cumulus Cloud Model (액적의 크기 분포를 고려한 일차원 적운 모델의 개발에 관한 연구)

  • 곽노혁;김이호;홍민선
    • Journal of Korean Society for Atmospheric Environment
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    • v.6 no.2
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    • pp.176-182
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    • 1990
  • A one dimensional cumulus cloud model has been developed to investigate the size distribution of hydrometeors at different heights and at different stages of cloud development. The model results show that the exponential distribution of droplet radius that was employed by many investigators can misinterpret the cloud dynamic fields during the life cycle of cumulus cloud. The results also show the bimodal distribution of cloud water mixing ratios at 25 $\mu$m and 645 $\mu$m in radius at 45 minutes of simulation time. The developed model can be applied in future on the parameterization of cloud microphysical processes and air pollution models.

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Analytical solutions for bending of transversely or axially FG nonlocal beams

  • Nguyen, Ngoc-Tuan;Kim, Nam-Il;Lee, Jaehong
    • Steel and Composite Structures
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    • v.17 no.5
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    • pp.641-665
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    • 2014
  • This paper presents the analytical solutions for the size-dependent static analysis of the functionally graded (FG) beams with various boundary conditions based on the nonlocal continuum model. The nonlocal behavior is described by the differential constitutive model of Eringen, which enables to this model to become effective in the analysis and design of nanostructures. The elastic modulus of beam is assumed to vary through the thickness or longitudinal directions according to the power law. The governing equations are derived by using the nonlocal continuum theory incorporated with Euler-Bernoulli beam theory. The explicit solutions are derived for the static behavior of the transversely or axially FG beams with various boundary conditions. The verification of the model is obtained by comparing the current results with previously published works and a good agreement is observed. Numerical results are presented to show the significance of the nonlocal effect, the material distribution profile, the boundary conditions, and the length of beams on the bending behavior of nonlocal FG beams.

Nonlinear magneto-electro-mechanical vibration analysis of double-bonded sandwich Timoshenko microbeams based on MSGT using GDQM

  • Mohammadimehr, M.;Shahedi, S.
    • Steel and Composite Structures
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    • v.21 no.1
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    • pp.1-36
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    • 2016
  • In the present study, the nonlinear magneto-electro-mechanical free vibration behavior of rectangular double-bonded sandwich microbeams based on the modified strain gradient theory (MSGT) is investigated. It is noted that the top and bottom sandwich microbeams are considered with boron nitride nanotube reinforced composite face sheets (BNNTRC-SB) with electrical properties and carbon nanotube reinforced composite face sheets (CNTRC-SB) with magnetic fields, respectively, and also the homogenous core is used for both sandwich beams. The connections of every sandwich beam with its surrounding medium and also between them have been carried out by considering Pasternak foundations. To take size effect into account, the MSGT is introduced into the classical Timoshenko beam theory (CT) to develop a size-dependent beam model containing three additional material length scale parameters. For the CNTRC and BNNTRC face sheets of sandwich microbeams, uniform distribution (UD) and functionally graded (FG) distribution patterns of CNTs or BNNTs in four cases FG-X, FG-O, FG-A, and FG-V are employed. It is assumed that the material properties of face sheets for both sandwich beams are varied in the thickness direction and estimated through the extended rule of mixture. On the basis of the Hamilton's principle, the size-dependent nonlinear governing differential equations of motion and associated boundary conditions are derived and then discretized by using generalized differential quadrature method (GDQM). A detailed parametric study is presented to indicate the influences of electric and magnetic fields, slenderness ratio, thickness ratio of both sandwich microbeams, thickness ratio of every sandwich microbeam, dimensionless three material length scale parameters, Winkler spring modulus and various distribution types of face sheets on the first two natural frequencies of double-bonded sandwich microbeams. Furthermore, a comparison between the various beam models on the basis of the CT, modified couple stress theory (MCST), and MSGT is performed. It is illustrated that the thickness ratio of sandwich microbeams plays an important role in the vibrational behavior of the double-bonded sandwich microstructures. Meanwhile, it is concluded that by increasing H/lm, the values of first two natural frequencies tend to decrease for all amounts of the Winkler spring modulus.

Effects of the Net Contrast of a Model Codend on the Escapement of Juvenile Red Seabream Pagrus major

  • Kim, Yong-Hae;Whang, Dae-Sung
    • Fisheries and Aquatic Sciences
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    • v.14 no.2
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    • pp.130-137
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    • 2011
  • Visual stimuli of nets, which affect fishing selectivity, vary by twine diameter, color, and material under different light conditions and visual geometries. In this study, two cylindrical model codends of two mesh sizes, 28 and 43 mm, were made of high-contrast, dark brown polyethylene (PE) netting twine and low contrast, light-blue polyamid (PA) monofilament twine. Each model codend was filled with juvenile seabream and set in the water channel of a light-blue circular tank under a flow speed 0.8 m/s for 30 min. Light conditions were set to relatively bright, dim, and dark. The resulting retention rates of juvenile seabream were 15-35% lower for the low-contrast codend with PA monofilament than for the high contrast PE twine netting under bright and dim light conditions, while no difference was observed under dark conditions. The effects of mesh size and netting contrast on the retention rate were dependent on the light level, while the retention rate due to netting contrast was independent of mesh size. Therefore, low-contrast nets in the codend could help to reduce juvenile bycatch by disturbing the orderly optomotor response.