• Title/Summary/Keyword: model change

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The Pahlev Reliability Index: A measurement for the resilience of power generation technologies versus climate change

  • Norouzi, Nima
    • Nuclear Engineering and Technology
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    • v.53 no.5
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    • pp.1658-1663
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    • 2021
  • Research on climate change and global warming on the power generation systems are rapidly increasing because of the Importance of the sustainable energy supply, thus the electricity supply since its growing share, in the end, uses energy supply. However, some researchers conducted this field, but many research gaps are not mentioned and filled in this field's literature since the lack of general statements and the quantitative models and formulation of the issue. In this research, an exergy-based model is implemented to model a set of six power generation technologies (combined cycle, gas turbine, nuclear plant, solar PV, and wind turbine) and use this model to simulate each technology's responses to climate change impacts. Finally, using these responses to define and calculate a formulation for the relationship between the system's energy performance in different environmental situations and a dimensionless index to quantize each power technology's reliability against the climate change impacts called the Pahlev reliability index (P-index) of the power technology. The results have shown that solar and nuclear technologies are the most, and wind turbines are the least reliable power generation technologies.

Organizational Change Readiness, Service Innovation, and Corporate Image in Improving Competitiveness: A Case Study in Indonesia

  • HUTAPEA, John Gunung;NIMRAN, Umar;IQBAL, Mohammad;HIDAYAT, Kadarisman
    • The Journal of Asian Finance, Economics and Business
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    • v.8 no.3
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    • pp.683-693
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    • 2021
  • Shipping has become an important sector in supporting social, economic, government, defense, security, cultural and other sectors to unite separate islands and broad seas. Thus, ports automatically become an important facility in Indonesia. The purpose of this research is to test and explain the effect of Organizational readiness for change, Service Innovation, and Corporate Image on Perceived opportunity and challenge. The research model with inferential analysis uses Structural Equation Modeling (SEM) analysis with the WarpPLS approach, expected to answer the statements of problem and be able to test the desired hypothesis. The model development in this research was based on the background, statements of problem, conceptual framework and research hypotheses. The model referred to is "Complete and Comprehensive Port." Its development was carried out through studying and synthesizing various sources. The most important source is the results of literature review in the form of theoretical developments and research results, then continued with compilation. The use of Organizational Change Readiness, Service Innovation, and Corporate Image in improving Port Competitiveness is seen as one of the novelties of this research, specifically the use of the Organizational Change Readiness variable which is often used in high-flexibility companies but now used in port companies as well.

Prediction of Three Dimensional Turbulent flows around a MIRA Vehicle Model (MIRA Vehicle Model 주위의 3차원 난류유동 예측)

  • 명현국;진은주
    • Transactions of the Korean Society of Automotive Engineers
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    • v.6 no.5
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    • pp.86-96
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    • 1998
  • A numerical study has been carried out of three-dimensional turbulent flows around a MIRA reference vehicle model both with and without wheels in computation. Two convective difference schemes with two k-$\varepsilon$ turbulence models are evaluated for the performance such as drag coefficient, velocity and pressure fields. Pressure coefficients along the surfaces of the model are compared with experimental data. The drag coefficient, the velocity and pressure fields are found to change considerably with the adopted finite difference schemes. Drag forces computed in the various regions of the model indicate that design change decisions should not rely just on the total drag and that local flow structures are important. The results also indicate that the RNG model with the QUICK scheme predicts fairly well the tendency of velocity and pressure fields and gives more reliable drag coefficient rather than the other cases.

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Emotional Engine Model based on Linear Dynamic Systems (선형 동적 시스템 기반의 감정 엔진 모델)

  • Ahn, Ho-Seok;Choi, Jin-Young
    • Proceedings of the KIEE Conference
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    • 2007.04a
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    • pp.213-215
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    • 2007
  • This paper introduces an emotional behavior decision model for intelligent service robots. An emotional model should make different behavior decisions according to the purpose of the robots. We propose an emotional behavior decision model which can change the character of emotional model and make different behavior decisions although the situation and environment remain the same. We defined each emotional element such as reactive dynamics, internal dynamics, emotional dynamics, and behavior dynamics by state dynamic equations. The proposed system model is a linear system. If you want to add one external stimulus or behavior, you need to add just one dimensional vector to the matrix of external stimulus or behavior dynamics. The case of removing is same. The change of reactive dynamics, internal dynamics, emotional dynamics, and behavior dynamics also follows the same procedure. We implemented the proposed emotional behavior decision model and verified its performance.

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Projection of Future Water Supply Sustainability in Agricultural Reservoirs under RCP Climate Change Scenarios (기후변화 시나리오를 고려한 농업용 저수지의 미래 용수공급 지속가능성 전망)

  • Nam, Won-Ho;Hong, Eun-Mi;Kim, Taegon;Choi, Jin-Yong
    • Journal of The Korean Society of Agricultural Engineers
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    • v.56 no.4
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    • pp.59-68
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    • 2014
  • Climate change influences multiple environmental aspects, certain of which are specifically related to agricultural water resources such as water supply, water management, droughts and floods. Understanding the impact of climate change on reservoirs in relation to the passage of time is an important component of water resource management for stable water supply maintenance. Changes on rainfall and hydrologic patterns due to climate change can increases the occurrence of reservoir water shortage and affect the future availability of agricultural water resources. It is a main concern for sustainable development in agricultural water resources management to evaluate adaptation capability of water supply under the future climate conditions. The purpose of this study is to predict the sustainability of agricultural water demand and supply under future climate change by applying an irrigation vulnerability assessment model to investigate evidence of climate change occurrences at a local scale with respect to potential water supply capacity and irrigation water requirement. Thus, it is a recommended practice in the development of water supply management strategies on reservoir operation under climate change.

Change-point and Change Pattern of Precipitation Characteristics using Bayesian Method over South Korea from 1954 to 2007 (베이지안 방법을 이용한 우리나라 강수특성(1954-2007)의 변화시점 및 변화유형 분석)

  • Kim, Chansoo;Suh, Myoung-Seok
    • Atmosphere
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    • v.19 no.2
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    • pp.199-211
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    • 2009
  • In this paper, we examine the multiple change-point and change pattern in the 54 years (1954-2007) time series of the annual and the heavy precipitation characteristics (amount, days and intensity) averaged over South Korea. A Bayesian approach is used for detecting of mean and/or variance changes in a sequence of independent univariate normal observations. Using non-informative priors for the parameters, the Bayesian model selection is performed by the posterior probability through the intrinsic Bayes factor of Berger and Pericchi (1996). To investigate the significance of the changes in the precipitation characteristics between before and after the change-point, the posterior probability and 90% highest posterior density credible intervals are examined. The results showed that no significant changes have occurred in the annual precipitation characteristics (amount, days and intensity) and the heavy precipitation intensity. On the other hand, a statistically significant single change has occurred around 1996 or 1997 in the heavy precipitation days and amount. The heavy precipitation amount and days have increased after the change-point but no changes in the variances.

Tsunami-induced Change Detection Using SAR Intensity and Texture Information Based on the Generalized Gaussian Mixture Model

  • Jung, Min-young;Kim, Yong-il
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.34 no.2
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    • pp.195-206
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    • 2016
  • The remote sensing technique using SAR data have many advantages when applied to the disaster site due to its wide coverage and all-weather acquisition availability. Although a single-pol (polarimetric) SAR image cannot represent the land surface better than a quad-pol SAR image can, single-pol SAR data are worth using for disaster-induced change detection. In this paper, an automatic change detection method based on a mixture of GGDs (generalized Gaussian distribution) is proposed, and usability of the textural features and intensity is evaluated by using the proposed method. Three ALOS/PALSAR images were used in the experiments, and the study site was Norita City, which was affected by the 2011 Tohoku earthquake. The experiment results showed that the proposed automatic change detection method is practical for disaster sites where the large areas change. The intensity information is useful for detecting disaster-induced changes with a 68.3% g-mean, but the texture information is not. The autocorrelation and correlation show the interesting implication that they tend not to extract agricultural areas in the change detection map. Therefore, the final tsunami-induced change map is produced by the combination of three maps: one is derived from the intensity information and used as an initial map, and the others are derived from the textural information and used as auxiliary data.

Econometric Estimation of the Climate Change Policy Effect in the U.S. Transportation Sector

  • Choi, Jaesung
    • Journal of Climate Change Research
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    • v.8 no.1
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    • pp.1-10
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    • 2017
  • Over the past centuries, industrialization in developed and developing countries has had a negative impact on global warming, releasing $CO_2$ emissions into the Earth's atmosphere. In recent years, the transportation sector, which emits one-third of total $CO_2$ emissions in the United States, has adapted by implementing a climate change action plan to reduce $CO_2$ emissions. Having an environmental policy might be an essential factor in mitigating the man-made global warming threats to protect public health and the coexistent needs of current and future generations; however, to my best knowledge, no research has been conducted in such a context with appropriate statistical validation process to evaluate the effects of climate change policy on $CO_2$ emission reduction in recent years in the U.S. transportation. The empirical findings using an entity fixed-effects model with valid statistical tests show the positive effects of climate change policy on $CO_2$ emission reduction in a state. With all the 49 states joining the climate change action plans, the U.S. transportation sector is expected to reduce its $CO_2$ emissions by 20.2 MMT per year, and for the next 10 years, the cumulated $CO_2$ emission reduction is projected to reach 202.3 MMT, which is almost equivalent to the $CO_2$ emissions from the transportation sector produced in 2012 by California, the largest $CO_2$ emission state in the nation.

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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    • v.7 no.10
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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.

Numerical Simulation of Local Scour in Front of Impermeable Submerged Breakwater Using 2-D Coupled Hydro-morphodynamic Model (2차원 연성모델을 적용한 불투과성 잠제 전면의 국부세굴 모의)

  • Lee, Woo-Dong;Lee, Jae-Cheol;Jin, Dong-Hwan;Hur, Dong-Soo
    • Journal of Ocean Engineering and Technology
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    • v.30 no.6
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    • pp.484-497
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    • 2016
  • In order to understand the characteristics of the topography change in front of an impermeable breakwater, a coupled model for a two-way analysis of the existing LES-WASS-2D and newly developed morphodynamic model was suggested. A comparison to existing experimental results revealed that the results computed using the 2-D hydro-morphodynamic model were in good agreement with the experimental results for the wave form, pore water pressure in the seabed, and topographical change in front of a submerged breakwater. It was shown that the two-way model suggested in this study is applicable to a morphological change in the seabed around a submerged breakwater. Then, using the numerical results, the topographical changes in front of an impermeable submerged breakwater were examined in relation to partial standing waves. Moreover, the characteristics of the local scour depths in front of them are also discussed in relation to incident wave conditions, sediment qualities, and submerged breakwater shapes.