• Title/Summary/Keyword: Dynamic factors

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A Dynamic Approach to Understanding Business Performance

  • Kusuma Indawati HALIM
    • Journal of Distribution Science
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    • v.22 no.6
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    • pp.1-10
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    • 2024
  • Purpose: This study's objective is to examine the impact of firm-specific and macroeconomic factors on the business performance of non-cyclical and cyclical sectors in Indonesian listed firms. The evaluation of business performance holds paramount importance for the achievement and long-term viability of a company. Research Design Data and Methodology: The data for 61 non-cyclicals sector companies and 57 cyclicals sector companies was gathered over a 4-year period from 2018-2021. The model integrates firm size, leverage, and sales growth as firm-specific factors, with real GDP growth and inflation rate as macroeconomic variables. ROA and ROE are indicators of a firm's business performance. The regression models are estimated using the distribution of a dynamic approach with Arellano-Bond Panel Generalized Method of Moments (GMM) estimation. Results: The results of the pooled sample indicate that the historical ROA and ROE have a positive relationship with the business performance of all sectors, including both non-cyclical and cyclical industries. The ROE of non-cyclical enterprises is primarily influenced by firm-specific characteristics and macroeconomic influences. Conclusion: To ensure the successful implementation of the distribution of a dynamic approach towards enhancing corporate business performance, organizations need to take into account a combination of firm-specific factors and macroeconomic factors.

Dynamic Analysis of a Washing Machine Using a Multi-body Dynamic Model (다물체 동역학 모델을 이용한 세탁기의 동적 해석)

  • Kim, Tae-Jin;Kim, Byung-Jin;Kim, Seung-Oh;Min, Je-Hong;Chung, Jin-Tai
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.22 no.1
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    • pp.88-93
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    • 2012
  • In this study, a multi-body dynamic model is developed for a washing machine and the dynamic behaviors of the machine are investigated. The mechanical properties such as spring constants and damping factors are measured from vibrational experiments. With these experimentally obtained mechanical properties, a computer simulation model for the washing machine is established by using a commercial multi-body dynamics software DAFUL. In order to verify the developed simulation model, the dynamic responses computed from simulation are compared to the responses measured from vibration experiments. In addition, the effects of the stiffness and damping factors on the dynamic responses are also analyzed.

Comparison of Wedge Factors of Dynamic Wedge and Physical Wedge (기능상쐐기와 물질쐐기의 쐐기인수의 비교)

  • Kim Jae Sung;Kang Wee-Saing
    • Progress in Medical Physics
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    • v.15 no.4
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    • pp.237-246
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    • 2004
  • Even though the wedge factor was defined by ICRU, RTPS uses other definition different from the wedge factor to consider the wedge effect to correct dose. Because the factors with different concept are defined in a very different way, replacement of different factor could make severe error of dose and is unacceptable because their values are very different from each other. Radiotherapy machine installed in department includes physical wedges and function of dynamic wedge by upper jaws, and Eclipse and Pinnacle$^{3}$ such as RTPS are used. The wedge factors, relative wedge output factors and wedge field output factors of physical wedges and dynamic wedges were measured by an ionization chamber in water phantom. They are analyzed and compared in according to wedge position, field size, wedge angle, X-ray quality, measurement condition. Wedge factor, relative wedge output factors and wedge field output factors of dynamic wedges comparing physical wedges have an effect of several factors. Main factors effecting to the factors of dynamic wedges were field size and wedge angle. Beam quality of X-ray introduces a few effect to the factors. Because the factors related to wedge and defined with different concepts are different from each other, to reduce dose error it should be input by values proper to RTPS.

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Dynamic risk assessment of water inrush in tunnelling and software development

  • Li, L.P.;Lei, T.;Li, S.C.;Xu, Z.H.;Xue, Y.G.;Shi, S.S.
    • Geomechanics and Engineering
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    • v.9 no.1
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    • pp.57-81
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    • 2015
  • Water inrush and mud outburst always restricts the tunnel constructions in mountain area, which becomes a major geological barrier against the development of underground engineering. In view of the complex disaster-causing mechanism and difficult quantitative predictions of water inrush and mud outburst, several theoretical methods are adopted to realize dynamic assessment of water inrush in the progressive process of tunnel construction. Concerning both the geological condition and construction situation, eleven risk factors are quantitatively described and an assessment system is developed to evaluate the water inrush risk. In the static assessment, the weights of eight risk factors about the geological condition are determined using Analytic Hierarchy Process (AHP). Each factor is scored by experts and the synthesis scores are weighted. The risk level is ultimately determined based on the scoring outcome which is derived from the sum of products of weights and comprehensive scores. In the secondary assessment, the eight risk factors in static assessment and three factors about construction situation are quantitatively analyzed using fuzzy evaluation method. Subordinate levels and weight of factors are prepared and then used to calculate the comprehensive subordinate degree and risk level. In the dynamic assessment, the classical field of the eleven risk factors is normalized by using the extension evaluation method. From the input of the matter-element, weights of risk factors are determined and correlation analysis is carried out to determine the risk level. This system has been applied to the dynamic assessment of water inrush during construction of the Yuanliangshan tunnel of Yuhuai Railway. The assessment results are consistent with the actual excavation, which verifies the rationality and feasibility of the software. The developed system is believed capable to be back-up and applied for risk assessment of water inrush in the underground engineering construction.

Structural Optimization under Equivalent Static Loads Transformed from Dynamic Loads Based on Displacement (변위에 기초한 동하중에서 변환된 등가정하중하에서의 구조최적설계)

  • Gang, Byeong-Su;Choe, U-Seok;Park, Gyeong-Jin
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.24 no.8 s.179
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    • pp.1949-1957
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    • 2000
  • All the loads in the real world act dynamically on structures. Since dynamic loads are extremely difficult to handle in analysis and design, static loads are utilized with dynamic factors. The dyna mic factors are generally determined based on experiences. Therefore, the static loads can cause problems in precise analysis and design. An analytical method based on modal analysis has been proposed for the transformation of dynamic loads into equivalent static load sets. Equivalent static load sets are calculated to generate an identical displacement field in a structure with that from dynamic loads at a certain time. The process is derived and evaluated mathematically. The method is verified through numerical tests. Various characteristics are identified to match the dynamic and the static behaviors. For example, the opposite direction of a dynamic load should be considered due to the vibration response. A dynamic bad is transformed to multiple equivalent static loads according to the number of the critical times. The places of the equivalent static load can be different from those of the dynamic load. An optimization method is defined to use the equivalent static loads. The developed optimization process has the same effect as the dynamic optimization which uses the dynamic loads directly. Standard examples are solved and the results are discussed

Dynamic Stress Intensity Factor $K_{IIID}$ for a Propagating Crack in Liner Functionally Gradient Materials Along X Direction (X방향의 선형함수구배인 재료에서 전파하는 균열의 동적응력확대계수 $K_{IIID}$)

  • Lee, Kwang-Ho
    • Proceedings of the KSME Conference
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    • 2001.11a
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    • pp.3-8
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    • 2001
  • Dynamic stress intensity factors (DSIFs) are obtained when a crack propagates with constant velocity in rectangular functionally gradient materials (FGMs) under dynamic mode III load. To obtain the dynamic stress intensity factors, it is used the general stress and displacement fields of FGMs for propagating crack and the boundary collocation method (BCM). The stress intensity factors and energy release rates are the greatest in the increasing properties $(\xi>0)$, next constant properties $(\x=0)$ and decreasing properties $(\xi<0)$ under constant crack tip properties and crack tip speed.

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A Study on Dynamic Characteristics Improvement of Fast Response Proportional Flow Control Valve (고응답 비래 유량제어 밸브의 동특성 향상에 관한 연구)

  • 김고도;김원수;이현철;윤소남
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1996.11a
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    • pp.1053-1057
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    • 1996
  • The purpose of this study is to bring out the optimal design factors which effect on dynamic characteristics in the design of proportional flow control valve with fast response characteristics, and to verify the validity of the design factors In this study, force feedback type flow control valve with nozzle-flapper is studied. And, the influences which fixed orifice, nozzle diameter, and maximum displacement between nozzle and flapper effect on dynamic characteristics are analyzed. We have done simulations using the optimal design factors and simulink(Matlab) as a simulation tool, and verified the validity of our simulations by means of comparison our simulation results with an experimental results of another similar valve.

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The buckling of a cross-ply laminated non-homogeneous orthotropic composite cylindrical thin shell under time dependent external pressure

  • Sofiyev, A.H.
    • Structural Engineering and Mechanics
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    • v.14 no.6
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    • pp.661-677
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    • 2002
  • The subject of this investigation is to study the buckling of cross-ply laminated orthotropic cylindrical thin shells with variable elasticity moduli and densities in the thickness direction, under external pressure, which is a power function of time. The dynamic stability and compatibility equations are obtained first. These equations are subsequently reduced to a system of time dependent differential equations with variable coefficients by using Galerkin's method. Finally, the critical dynamic and static loads, the corresponding wave numbers, the dynamic factors, critical time and critical impulse are found analytically by applying a modified form of the Ritz type variational method. The dynamic behavior of cross-ply laminated cylindrical shells is investigated with: a) lamina that present variations in the elasticity moduli and densities, b) different numbers and ordering of layers, and c) external pressures which vary with different powers of time. It is concluded that all these factors contribute to appreciable effects on the critical parameters of the problem in question.

Torsional Vibration Analysis of a Spur Gear Pair with the Variable Mesh Stiffness (기어이의 변동물림강성을 고려한 비틀림진동해석)

  • Ryu, Jae-Wan;Han, Dong-Chul;Choi, Sang-Hyun
    • Journal of the Korean Society for Precision Engineering
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    • v.16 no.12
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    • pp.99-108
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    • 1999
  • A four-degree-of-freedom non-linear model with time varying mesh stiffness has been developed for the dynamic analysis of spur gear trains. The model includes a spur gear pair, two shafts, two inertias representing load and prime mover. In the model, developed several factors such as time varying mesh stiffness and damping, separation of teeth, teeth collision, various gear errors and profile modifications have been considered. Two computer programs are developed to calculate stiffness of a gear pair and transmission error and the dynamic analysis of modeled system using time integration method. Dynamic tooth and mesh forces, dynamic factors are calculated. Numerical examples have been given, which shows the time varying mesh stiffness ha a significant effect upon the dynamic tooth force and torsional vibrations.

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Analysis of Influence Factors on Dynamic Properties of Floor Impact Noise Insulation Materials (바닥충격음 완충재의 동적특성에 영향을 미치는 요인 분석)

  • Kim, Heung-Sik;Joo, Si-Woong;Kim, Dae-Jun;Kim, Byeung-Jin
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2005.11a
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    • pp.946-949
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    • 2005
  • In this paper, influence factors on dynamic properties of floor impact noise insulation materials are suggested. For this purpose measurements on the dynamic stiffness and the loss factor of resilient materials are carried out by Korea standard (KS F 2868) according to the change of density, thickness, design pattern, and composition of materials. As a result the values of dynamic stiffness was decreased at high density and thick thickness, and that of loss factor was increased at low density. For dynamic properties, the pattern of lattice and waffle type material is better than that of plat type, and the mixed composition of materials is better than the composition of double layer materials at same thickness.

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