• Title/Summary/Keyword: a variable reference model

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Decomposition and Super-efficiency in the Korean Life Insurance Industry Employing DEA

  • Lee, Hyung-Suk;Kim, Ki-Seog
    • International Journal of Contents
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    • v.4 no.3
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    • pp.1-9
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    • 2008
  • The Korean life insurance industry has undergone profound changes, such as the beginning of the variable insurance in July 2001 and the bancassurance enforcement in August 2003. However, little empirical research has analyzed data that includes the bancassurance of life insurance companies operating in Korea. In response to this lack of research, this paper applies DEA (data envelopment analysis) models to measure and decompose their efficiency. We discovered that life insurance companies operating in Korea are a little different in their composition ratio of inputs and outputs, due to the increased variety of distribution channels and new products. We provided efficiency scores, return to scale, and reference frequencies. We also decomposed CCR, BCC, and SBM efficiency into scale efficiency and MIX efficiency. So, we try to investigate whether the sources of inefficiency were caused by the inefficient operation of DMU, disadvantageous conditions, the difference of the composition ratio in inputs and outputs with reference sets, or any combination of the above. Most companies in the sample display had either constant or decreasing returns to scale. The efficiency rankings were less consistent among models and efficient DMUs. In response to this problem, we used the super-efficiency model to rank them and then compared the rankings of the DMUs among the various models. It was also concluded that the availability of panel data, rather than cross-sectional data, would greatly improve the validity of the efficiency estimates.

A Study on Efficient Coding Mode Decision for H.264/AVC (H.264/AVC의 효율적인 부호화 모드 결정에 관한 연구)

  • Hur, Tae-Won
    • Journal of the Korea Computer Industry Society
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    • v.6 no.5
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    • pp.801-812
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    • 2005
  • H.264/AVC is the international video coding standard which has significant improvements of coding efficiency. ITU-T(International Telecommunication Union-Telecommunication standardization sector) and MPEG(Moving Picture Experts Group) adopts various complex coding tool such as variable block size motion, multiple reference frames, quarter-pel motion estimation/compensation (ME/MC) and rate-distortion(RD) optimization, etc. H.264 reference model employs complex mode decision technique based on RD optimization which requires high computational complexity. In this paper, we propose an efficient coding mode decision based on the cost distribution of RD in the macroblock coding mode sequence. Simulation results show that the proposed method reduces encoding time by 34% on average and save the number of computing RD cost by 82%.

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Determinants Influencing the Conversion of Financial Statements: The Case of Multinational Firms in Vietnam

  • TRAN, Manh Dung;NGO, Thi Tuyet Mai;PHAN, To Uyen;DO, Duc Tai;PHAM, Thi Thuy Hang
    • The Journal of Asian Finance, Economics and Business
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    • v.7 no.3
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    • pp.17-27
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    • 2020
  • The research aims to investigate the impact levels of determinants on the conversion of financial statements from Vietnamese accounting standards (VAS) to International financial reporting standards (IFRS) in the multinational firms in Vietnam. The method of data collection was done through the survey and subjects are accountants in Multinational Firms doing business in Hanoi and ten neighboring provinces. After checking the information on the votes, there are 170 questionnaires with full information for data entry and analysis. We use Cronbach's Alpha, EFA analysis and run regression model to investigate the impact levels of each independent variable on dependent variable of the conversion of VAS financial statements to IFRS. The results show that five determinants including Economic, Politics, Law, Culture, and Conditions for implementation have positive relationships with the conversion of VAS financial statements to IFRS. In particular, Economic determinant is the most strongest. Based on the findings, some recommendations are given for improving the conversion of VAS financial statements to IFRS of multinational firms doing business in the context of Vietnam. The results are considered a useful reference for firms when making financial statements to transparently change the financial statement information and improve the quality of financial statement information.

NUMERICAL PREDICTION OF THE OPTIMAL STAGGER ANGLES FOR A HIGH-POWER TURBO BLOWER (고마력 터보 블로어의 최적 깃배치각에 관한 수치 예측)

  • Park, T.G.;Chung, H.T.;Park, J.Y.;Sung, B.I.
    • Journal of computational fluids engineering
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    • v.16 no.3
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    • pp.75-81
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    • 2011
  • The turbo blowers having large power capacity are generally composed of the variable inlet guide vane, the impeller and the variable diffuser. In the present study, the effect of the stagger angles on the aerodynamic performances has been investigated by CFD methods. The design specifications of the reference model having 400kW power were given as 7.43kg/s of mass flow rate, 1.66 of pressure ratio with 12000rpm of impeller rotating speed. As the first simulation parameter, the diffuser vane angle was varied in the range of ${\pm}$20 degree from the initial-design point. The inlet guide vane angles, as the second one, was changed in the range of ${\pm}$40 degree from the initial-design point. The commercial Navier-Stokes solver, ANSYS-CFX, was applied to solve the three-dimensional unsteady flow fields inside the turbo blower. Through the numerical results, the desirable setting angles were proposed to fit the best performance to the variation of the operating conditions.

A Structural Model for Health Promotion and Life Satisfaction of Life in College Students in Korea (대학생들의 건강증진행위와 삶의 만족도에 대한 구조모형)

  • Hong, Youn-Lan;Yi, Ga-Eon;Park, Hyun-Sook
    • Research in Community and Public Health Nursing
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    • v.11 no.2
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    • pp.333-346
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    • 2000
  • The purpose of this study was designed to test and develope the structural model that explains health promoting behaviors among college students in Korea. The hypothetical model was constructed on the Pender's Health promotion Model(l996) and the inclusion of some influential factors for life satisfaction. The conceptual framework was built around eight constructs. Exogenous variables included in the model were self-esteem, perceived health status, self-efficacy, internal locus of control, chance locus of control. powerful other locus of control. Endogenous variables were health promotion behaviors and life satisfaction. The results are as follows; 1. The overall fit of the hypothetical model to the data was moderate <$x^2$=4.18(df=11. p=0.041), GFI= 0.99, AGFI= 0.76, RMR= 0.019, CFI= 0.99, CN= 248.50> 2. Path and variable of the model were modified by considering both its theoretical implication and statistical significance of parameter estimates. Compared to the hypothetical model. the revised model has become parsimonious and had a better fit to the data expected in a chi-square value <$x^2$=8.43( df= 16, p=0.21), GFI= 0.99, AGFI= 0.92., RMR= 0.024, CFI= 0.99, CN= 312.01> 3. Some of the predictive factors. especially self efficacy. self esteem. powerful others locus of control. perceived health status revealed the direct effects on health promoting behaviors. Of these variables. self-efficacy was the most signigicant factor. These predictive variables of health promoting behaviors explained 59% of total variances in the model. 4. Health promoting behaviors, self-esteem. and perceived health status revealed direct effect on the life satisfaction. Self-efficacy was identified as an important variable that contributed indirectly to improve life satisfaction by enhancing health promoting behaviors. These predictive variables of life satisfaction explained 42% of total variances in the model. In conclusion. the derived model in this study is considered appropriate in explaining and predicting health promoting models and life satisfaction among college students in Korea and could effectively be used as a reference model for further studies by suggesting a direction in health promoting nursing practices.

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Practical Modeling and PI Controller Design for Centrifugal Water Chillers (터보냉동기를 위한 실용적 모델링과 PI 제어기 설계)

  • Jeong, Seok-Kwon;Han, Sung-Joon;Jung, Young-Mi
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.27 no.4
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    • pp.187-194
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    • 2015
  • This paper describes the PI controller design based on a practical transfer function model for centrifugal water chillers. The rotational speed of a compressor and the opening angle of an electronic expansion valve were simultaneously regulated as manipulated variables to maintain temperature reference and to ensure high efficiency of the chiller. The COP according to the change in each variable was investigated by performing some static experiments, and it was reflected in the PI controller design to accomplish the high efficiency control. Especially, the practical transfer function model of the chiller was built based on the dynamic experimental data considering the strong inherent non-linearity and complexity of the chiller system. The validity of the designed PI controller was proven by some experimental results using the test facility and the results were also compared to the conventional evaporating pressure control results.

A Study on the Efficiency of Fishing-Ports Based on Super-SBM (Super-SBM을 이용한 어항의 효율성분석에 관한 연구)

  • Park, Cheol-Hyung
    • The Journal of Fisheries Business Administration
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    • v.41 no.3
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    • pp.129-151
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    • 2010
  • This study is to analyze the efficiency of Korean fishing ports using DEA. First, the study calculated the efficiency scores based on a CCR-BCC framework and hence technical, pure technical, and scale efficiency scores are seperated for the 38 fishing ports under study. The Average of technical, pure technical, and scale efficiency are turned out to be 0.6834, 0.8582, and 0.7774 respectively. The 15 fishing ports are fully efficient under the constant returns to scale while 21 fishing ports under the variable returns to scale. Second, the super efficiency scores are also calculated under the radial model without the consideration of slacks. The highest score is turned out to be 4.4984 for the P16 fishing port with the average score of 0.9652 for the entire fishing ports. Nevertheless, P16 fishing port has showed up only once as a reference set. On the other hand, P34 fishing port has showed up 11 times as a reference set, which scored the second highest score of 2.9815. Finally the super efficiency scores are calculated under the non-radial model with the explicit consideration of slacks. Now the P34 fishing port scored the highest score of 2.3424 with even 15 times referred to a bench-mark. Therefore the importance of P34 fishing port is emphasized once again on the field of bench-marking for the efficiency of fishing ports. When the targets for the input factors to improve the efficiency of each DMU are calculated the area of fishing port needs the most adjustment to be reduced for 40.36% on the average, while the cosignment sales area does the least adjustment for 13.70%.

Hyperspectral imaging technique to evaluate the firmness and the sweetness index of tomatoes

  • Rahman, Anisur;Park, Eunsoo;Bae, Hyungjin;Cho, Byoung-Kwan
    • Korean Journal of Agricultural Science
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    • v.45 no.4
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    • pp.823-837
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    • 2018
  • The objective of this study was to evaluate the firmness and the sweetness index (SI) of tomatoes with a hyperspectral imaging (HSI) technique within the wavelength range of 1000 - 1550 nm. The hyperspectral images of 95 tomatoes were acquired with a push-broom hyperspectral reflectance imaging system, from which the mean spectra of each tomato were extracted from the regions of interest. The reference firmness and sweetness index of the same sample was measured and calibrated with their corresponding spectral data by partial least squares (PLS) regression with different preprocessing methods. The calibration model developed by PLS regression based on the Savitzky-Golay second-derivative preprocessed spectra resulted in a better performance for both the firmness and the SI of the tomatoes compared to models developed by other preprocessing methods. The correlation coefficients ($R_{pred}$) were 0.82, and 0.74 with a standard error of prediction of 0.86 N, and 0.63, respectively. Then, the feature wavelengths were identified using a model-based variable selection method, i.e., variable importance in projection, from the PLS regression analyses. Finally, chemical images were derived by applying the respective regression coefficients on the spectral image in a pixel-wise manner. The resulting chemical images provided detailed information on the firmness and the SI of the tomatoes. The results show that the proposed HSI technique has potential for rapid and non-destructive evaluation of firmness and the sweetness index of tomatoes.

Dynamic response of a linear two d.o.f system visco-elastically coupled with a rigid block

  • Di Egidio, Angelo;Pagliaro, Stefano;Fabrizio, Cristiano;de Leo, Andrea M.
    • Coupled systems mechanics
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    • v.8 no.4
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    • pp.351-375
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    • 2019
  • The present work investigates the use of a rigid rocking block as a tool to reduce vibrations in a frame structure. The study is based on a simplified model composed by a 2-DOF linear system, meant to represent a general M-DOF frame structure, coupled with a rocking rigid block through a linear visco-elastic device, which connects only the lower part of the 2-DOF system. The possibility to restrain the block directly to the ground, by means of a second visco-elastic device, is investigated as well. The dynamic response of the model under an harmonic base excitation is then analysed in order to evaluate the effectiveness of the coupling in reducing the displacements and the drift of the 2-DOF system. The nonlinear equations of motion of the coupled assemblage 2-DOF-block are obtained by a Lagrangian approach and then numerically integrated considering some reference mechanical and geometrical quantities as variable parameters. It follows an extensive parametric analysis, whose results are summarized through behaviour maps, which portray the ratio between the maximum displacements and drifts of the system, with and without the coupling with the rigid block, for several combinations of system's parameters. When the ratio of the displacements is less than unity, the coupling is considered effective. Results show that the presence of the rocking rigid block improves the dynamics of the system in large ranges of the characterizing parameters.

Implementation of Auto-reclosing Relay Algorithm based on Multi-Agent System using EMTP-MODELS (EMTP-MODELS를 이용한 Multi-Agent System 기반의 자동 재폐로 계전 알고리즘 구현)

  • Lee, Byung-Hyun;Yeo, Sang-Min;Lee, You-Jin;Kim, Chul-Hwan;Sung, No-Kyu
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.57 no.1
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    • pp.8-13
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    • 2008
  • This paper presents auto-reclosing algorithms with reference to power system stability based on MAS(Multi-Agent System). And this paper shows auto-reclosing algorithms considering power system stability. It includes the variable dead time, optimal reclosing, sequential reclosing, emergency extended equal-area criterion(EEEAC) algorithm, and modified EEEAC algorithm. This paper divides Auto-reclosing algorithms into respectively agents according to their tasks. A separated agent is merely a software entity that is situated in some environment and is able to autonomously react to changes in the environment. And all the simulations in this parer were tested by EMTP MODELS.