• 제목/요약/키워드: roe

검색결과 475건 처리시간 0.021초

와류 셀을 이용한 풍력블레이드 에어포일 주위 유동 제어 (Flow Control on Wind Turbine Airfoil with a Vortex Cell)

  • 강승희;김혜웅;유기완;이준신
    • 한국항공우주학회지
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    • 제40권5호
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    • pp.405-412
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    • 2012
  • 높은 효율의 풍력터빈 블레이드을 위해 와류 셀이 장착된 에어포일의 정지상태 및 동실 속 상태에서의 유동제어 특성을 수치적으로 연구하였다. 수치기법은 Roe의 flux-difference-splitting을 사용한 격자점 중심 유한체적법과 이중시간 전진 기법을 사용하는 내재적 시간적분법을 사용하였다. 계산결과 와류 셀을 장착한 경우 셀 내부의 부압으로 인해 양항비증가를 얻을 수 있음을 확인하였다. 동실속의 경우 셀 내부의 와류에 의해 hysterisis 현상을 상당히 감소시킬 수 있음을 확인하였다.

The Impact of Mergers on the Financial Performance of Jordanian Public Shareholding Companies

  • AYOUSH, Maha;RABAYAH, Hesham;JIBREEL, Thaer
    • The Journal of Asian Finance, Economics and Business
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    • 제7권10호
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    • pp.751-759
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    • 2020
  • This study examines the impact of mergers on the financial performance of the Jordanian public shareholding companies. The study employs data collected for a sample of 10 Jordanian non-financial public firms that were engaged in legal horizontal merger deals between 2000 and 2013. The data was collected from the published annual financial reports of the merging companies and comparative companies for three years before the merger and three years after the merger. Event study methodology was applied to examine the data. Four measures of financial performance (FP) were used, which are return on assets (ROA), return on equity (ROE), earnings per share (EPS), and net profit margin (NPM). Two methods were used in the analysis - the change model and the intercept model using financial performance raw data and industry-adjusted data. The findings in general showed no significant impact of mergers on the financial performance of merging firms using the change model. However, by using the intercept model, significant impact of mergers on the financial performance was found on the sample of the study. The significant impact was found for mergers on the raw ROE of the merging firms, and on the ROA and NPM of the industry-adjusted firms.

2차원 압축공기-물의 압축성 이상 유동 수치 해석 (Numerical Analysis for Two-Dimensional Compressible and Two-Phase Flow Fields of Air-Water in Eulerian Grid Framework)

  • 박찬욱;이승수
    • 대한기계학회논문집B
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    • 제32권6호
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    • pp.429-445
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    • 2008
  • Two-phase compressible flow fields of air-water are investigated numerically in the fixed Eulerian grid framework. The phase interface is captured via volume fractions of each phase. A way to model two phase compressible flows as a single phase one is found based on an equivalent equation of states of Tait's type for a multiphase cell. The equivalent single phase field is discretized using the Roe‘s approximate Riemann solver. Two approaches are tried to suppress the pressure oscillation phenomena at the phase interface, a passive advection of volume fraction and a direct pressure relaxation with the compressible form of volume fraction equation. The direct pressure equalizing method suppresses pressure oscillation successfully and generates sharp discontinuities, transmitting and reflecting acoustic waves naturally at the phase interface. In discretizing the compressible form of volume fraction equation, phase interfaces are geometrically reconstructed to minimize the numerical diffusion of volume fraction and relevant variables. The motion of a projectile in a water-filled tube which is fired by the release of highly pressurized air is simulated presuming the flow field as a two dimensional one, and several design factors affecting the projectile movement are investigated.

Numerical Simulation of Shock Wave Reflecting Patterns for Different Flow Conditions

  • Choi, Sung-Yoon;Oh, Se-Jong
    • International Journal of Aeronautical and Space Sciences
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    • 제3권1호
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    • pp.74-85
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    • 2002
  • The numerical experiment has been conducted to investigate the unsteady shock wave reflecting phenomena. The cell-vertex finite-volume, Roe's upwind flux difference splitting method with unstructured grid is implemented to solve unsteady Euler equations. The $4^{th}$-order Runge-Kutta method is applied for time integration. A linear reconstruction of the flux vector using the least-square method is applied to obtain the $2^{nd}$-order accuracy for the spatial derivatives. For a better resolution of the shock wave and slipline, the dynamic grid adaptation technique is adopted. The new concept of grid adaptation technique, which is much simpler than that of conventional techniques, is introduced for the current study. Three error indicators (divergence and curl of velocity, and gradient of density) are used for the grid adaptation procedure. Considering the quality of the solution and the numerical efficiency, the grid adaptation procedure was updated up to $2^{nd}$ level at every 20 time steps. For the convenience of comparison with other experimental and analytical results, the case of interaction between the straight incoming shock wave and a sharp wedge is simulated for various flow conditions. The numerical results show good agreement with other experimental and analytical results, in the shock wave reflecting structure, slipline, and the trajectory of the triple points. Some critical cases show disagreement with the analytical results, but these cases also have been proven to show hysteresis phenomena.

ABSORBED INTERNAL DOSE CONVERSION COEFFICIENTS FOR DOMESTIC REFERENCE ANIMALS AND PLANT

  • Keum, Dong-Kwon;Jun, In;Lim, Kwang-Muk;Choi, Yong-Ho
    • Nuclear Engineering and Technology
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    • 제42권1호
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    • pp.89-96
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    • 2010
  • This paper describes the methodology of calculating the internal dose conversion coefficient in order to assess the radiological impact on non-human species. This paper also presents the internal dose conversion coefficients of 25 radionuclides ($^3H,\;^7Be,\;^{14}C,\;^{40}K,\;^{51}Cr,\;^{54}Mn,\;^{59}Fe,\;^{58}Co,\;^{60}Co,\;^{65}Zn,\;^{90}Sr,\;^{95}Nb,\;^{99}Tc,\;^{106}Ru,\;^{129}I,\;^{131}I,\;^{136}Cs,\;^{137}Cs,\;^{140}Ba,\;^{140}La,\;^{144}Ce,\;^{238}U,\;^{239}Pu,\;^{240}Pu$) for domestic seven reference animals (roe deer, rat, frog, snake, Chinese minnow, bee, and earthworm) and one reference plant (pine tree). The uniform isotropic model was applied in order to calculate the internal dose conversion coefficients. The calculated internal dose conversion coefficient (${\mu}Gyd^{-1}$ per $Bqkg^{-1}$) ranged from $10^{-6}$ to $10^{-2}$ according to the type of radionuclides and organisms studied. It turns out that the internal does conversion coefficient was higher for alpha radionuclides, such as $^{238}U,\;^{239}Pu$, and $^{240}Pu$, and for large organisms, such as roe deer and pine tree. The internal dose conversion coefficients of $^{239}U,\;^{240}Pu,\;^{238}U,\;^{14}C,\;^3H$, and $^{99}Tc$ were independent of the organism.

Financial Performance of Converted Commercial Banks from Non-Banking Financial Institutions: Evidence from Bangladesh

  • GAZI, Md. Abu Issa;RAHAMAN, Atikur;WALIULLAH, Shaikh Sabbir Ahmed;ALI, Md. Julfikar;MAMOON, Zahidur Rahman
    • The Journal of Asian Finance, Economics and Business
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    • 제8권2호
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    • pp.923-931
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    • 2021
  • The aim of the present study is to analyze the financial performance of converted commercial bank from non-banking financial institution through a case study of Bangladesh Commerce Bank Limited as sample organization. It is observed that the bank is able to achieve a stable growth rate in total deposits, total loans and advances, and net income after tax during the period of 2015-2019. Researchers also calculated some ratio analysis and noticed that the financial position of Bangladesh Commerce Bank Limited was not so strong because bank's ROA, ROE, NIM and other ratios were below standard. Researchers used secondary data that were examined by using descriptive statistical tools and panel data regression model. Result shows that Bangladesh Commerce Bank has satisfactory operating efficiency, assets management efficiency, and gives loans to customers. In addition, the present study has tested some hypotheses regarding net income after tax, ROA and ROE with total assets, total loans, total deposits and interest income. These hypotheses have been accepted, which means there is no significant influence of the independent variable on the dependent variable. The study suggests that Bangladesh Commerce Bank Limited had the opportunities to make their financial position stronger by utilizing their good financial position and management efficiencies.

Relationship Between Profitability and Corporate Social Responsibility Disclosure: Evidence from Vietnamese Listed Banks

  • TRAN, Quoc Thinh;VO, Thi Diu;LE, Xuan Thuy
    • The Journal of Asian Finance, Economics and Business
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    • 제8권3호
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    • pp.875-883
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    • 2021
  • In view of integration and development, compliance with regulations on information disclosure has important implications for users. Corporate social responsibility disclosure (CSRD) is an increasing concern of the community and society. CSRD always poses many challenges for the profitability of banks. The article uses the ordinary least square method to examine this relationship and employs timeseries data of five years from 18 Vietnamese listed banks from 2015 to 2019. The analysis is informed by Jensen and Meckling's Agency theory, Freeman's Stakeholder theory, and Dowling and Pfeffer's Legitimacy theory. The study results show that, with the CSRD dependent variable, return on assets (ROA) and net interest margin (NIM) have an opposite influence, but return on equity (ROE) has no effect on CSRD, while on the profitability dependent variable, CSRD has a different influence from ROA, ROE, and NIM. To enhance the relationship between CSRD and profitability, Vietnamese listed banks need to comply with CSRD as well as demonstrate responsibility to the community and society. Managers need to have clear development policies and strategies to ensure both profitability and responsibility regarding social and community activities. The State Securities Commission of Vietnam should enforce strict sanctions, conduct inspection, and complete evaluation criteria for Vietnamese listed banks.

The Impact of Corporate Social Responsibility Dimensions on Firm Performance: A Perspective of Government-Linked Companies in Malaysia

  • ABD JAMIL, Farazila Rita;ALI, Mazurina Mohd;YEBOAH, Michael
    • The Journal of Asian Finance, Economics and Business
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    • 제9권7호
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    • pp.63-79
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    • 2022
  • Past studies on the influence of corporate social responsibility (CSR) activities on firms have been inconsistent, highlighting the significance of examining how CSR affects the performance of Malaysian government-linked companies (GLCs). The study aims to investigate the impact of CSR dimensions (economic, legal, ethical, and philanthropic) on firm performance from 2016 to 2020 using a sample of 31 GLCs from the top 100 companies under the Main Board of Bursa Malaysia. A total of 35 GLCs were selected as the study sample size based on the top 100 businesses listed under the board of Bursa Malaysia as of 31 December 2020. The study employed correlation and multiple linear regression models to examine the relationship between CSR dimensions and firm performance. Financial performance is evaluated using accounting-based models of return on assets (ROA) and return on equity (ROE) and market-based models of earnings per share (EPS) and market value (MV). The CSRHub database was employed to collect information on the performance of company CSR dimensions. The findings suggested a significant positive relationship between ethical and philanthropic CSR and firm performance regarding ROE. Thus, GLCs prioritized ethical and philanthropic CSR over other dimensions.

Corporate Governance and Performance of Insurance Companies in the Saudi Market

  • OSMAN, Mohamed Abdel Mawla;SAMONTARAY, Durga Prasad
    • The Journal of Asian Finance, Economics and Business
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    • 제9권4호
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    • pp.213-228
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    • 2022
  • This paper investigates the association between key corporate governance characteristics and the performance of general insurance businesses listed on the Saudi stock exchange (TADAWUL). The methodology for the study is based on a pooled data collection for 11 Saudi general insurance companies from 2011 to 20. The linear regression model and the logarithm regression model are suggested to assess the relationship between performance and corporate governance characteristics. The dependent variable is firm performance measured using ROA, ROE, and Tobin's Q. The independent variables are corporate governance variables consisting of a complete set of board and audit committee characteristics. Insurer-specific control variables are introduced. The empirical results reveal that the characteristics of corporate governance influence the performance of insurance companies. In particular, the board size, board's tenure, the proportion of independent directors in the board, audit committee size, audit committee meeting frequency, and proportion of health insurance premiums have a positive impact. However, audit committee independence, size of the company, and proportion of reinsurance premiums have a negative impact on the performance of the Saudi general insurance companies. Finally, the empirical results indicated also that there is an unclear relationship between the performance and board meeting frequency, compensations of the Board, and the average age of the Board.

Does a Firm's IPO Affect Other Firms in the Same Conglomerate?

  • Bhadra, Madhusmita;Kim, Doyeon
    • 아태비즈니스연구
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    • 제12권3호
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    • pp.37-50
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    • 2021
  • Purpose - This study aimed to examine the behavior surrounding the Initial Public Offering (IPO) event of firms within the same conglomerate and the impact of under-pricing and Return on Equity(ROE) on a firm's abnormal stock returns. Design/methodology - This study collected data from 166 South Korean Chaebols, consisting of 355 firms distributed as 202 listed on Korea Composite Stock Price Index (KOSPI) and 153 firms listed on Korean Securities Dealers Automated Quotations (KOSDAQ) from 2000 to 2020. The Capital Asset Pricing Model (CAPM) and the multiple regression analysis were hired to analyze the data. Findings - First, we found an adverse price reaction of IPO listing in the same chaebol group, and firms with higher under-pricing affect other firms' stock prices more adversely within the conglomerate. Next, we explored a negatively significant relation between ROE and the chaebol firms' stock returns during IPO events. Research implications - The novelty of this study is there are not many empirical studies on the impact of IPO within a conglomerate. So, the findings of this study contribute to the literature for analyzing stock's abnormal returns within a conglomerate.