• Journal of Electrical Engineering and Technology
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• v.9 no.5
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• pp.1729-1738
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• 2014

The offline verification of state of charge estimation, power estimation, fault diagnosis and emergency control of battery management system (BMS) is one of the key technologies in the field of electric vehicle battery system. It is difficult to test and verify the battery management system software in the early stage, especially for algorithms such as system state estimation, emergency control and so on. This article carried out the virtual environment modeling for verification of battery management system. According to the input/output parameters of battery management system, virtual environment is determined to run the battery management system. With the integration of the developed BMS model and the external model, the virtual environment model has been established for battery management system in the vehicle's working environment. Through the virtual environment model, the effectiveness of software algorithm of BMS was verified, such as battery state parameters estimation, power estimation, fault diagnosis, charge and discharge management, etc.

• The Transactions of the Korea Information Processing Society
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• v.7 no.6
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• pp.1810-1817
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• 2000

The purpose of this research is to develop an estimation model for information systems operating costs. Current cost estimation practices and types of sytem management projects have been reviewed an analyses. Typical operating project types of information systems are determined. They are application system operation, help disk operation, network management and operation, and hardware management. For each type of projects, cost factors ar identified and a structure of cost estimation model is defined. Cost estimation models have been constructed and tested by 24 real operation projects data. Statistical analysis shows derived models are statistically significant. User groups' opinion on these draft cost estimation model has been surveyed and summarized. The results of this research can be used as a cornerstone for future research on operating cost estimation, and for cost estimation guideline of information systems operation projects.

• Journal of Korean Institute of Industrial Engineers
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• v.42 no.4
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• pp.256-262
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• 2016

The Weibull is widely used in reliability analysis, and several studies have attempted to improve estimation of the distribution's parameters. least squares estimation (LSE) or Maximum likelihood estimation (MLE) are often used to estimate distribution parameters. However, it has been proven that Bayesian methods are more suitable for small sample sizes than LSE and MLE. In this work, the Weibull parameter estimation accuracy of LSE, MLE, and Bayesian method are compared for sample sets with 3 to 30 data points. The Bayesian method was most accurate for sample sizes under 25, and the accuracy of the Bayesian method was similar to LSE and MLE as the sample size increased.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2009.05b
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• pp.159-162
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• 2009

Today's construction is more various and more complex. Because of that, a lot of uncertain factors are occurred and they related uncertain construction duration. For management complex architecture project, importance of construction schedule management also increased. In previous studies, one of solutions to overcome those problems is suggested. It was BIM based construction simulation process which focused on construction schedule and construction schedule management. But latest process had limited point which has no duration estimation function. So this paper suggested duration estimation method and developed duration estimation module. Duration estimation module developed with current scheduling tool MS Project and their macro function. However, this module has just developed Reinforced Concrete Structure and has to do more development and research.

• Journal of Korean Society for Quality Management
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• v.9 no.1
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• pp.51-60
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• 1981

This paper deals with the estimation of the Weibull parameters, which have a close relation with product reliability characteristics. Among the many kinds of estimation methods, Ishikawa's Weibull Probability Paper (WPP) is commonly used. The WPP is very convenient, but it has a great disadvantage in estimation accuracy by plotting method. It is very difficult to get the same results even if one use the same data several times. A computer program for the regression method is used for the parameter estimation to reduce these errors.

• Journal of Korean Society for Quality Management
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• v.15 no.2
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• pp.61-68
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• 1987

This paper considers the estimation of the parameters of a normal population from which a sample which has been censored at a known point is obtained. Simple estimators are presented which are given in closed forms. It is shown that maximum likelihood estimators are obtained by using the estimation procedure iteratively. Some computer simulation results are given.

• Journal of Korea Society of Waste Management
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• v.35 no.8
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• pp.777-784
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• 2018

Since climate change increases the risk of extreme rainfall events, concerns on flood management have also increased. In order to rapidly recover from flood damages and prevent secondary damages, fast collection and treatment of flood debris are necessary. Therefore, a quick and precise estimation of flood debris generation is a crucial procedure in disaster management. Despite the importance of debris estimation, methodologies have not been well established. Given the intrinsic heterogeneity of flood debris from local conditions, a regional-scale model can increase the accuracy of the estimation. The objectives of this study are 1) to identify significant damage variables to predict the flood debris generation, 2) to ascertain the difference in the coefficients, and 3) to evaluate the accuracy of the debris estimation model. The scope of this work is flood events in Ulsan city region during 2008-2016. According to the correlation test and multicollinearity test, the number of damaged buildings, area of damaged cropland, and length of damaged roads were derived as significant parameters. Key parameters seems to be strongly dependent on regional conditions and not only selected parameters but also coefficients in this study were different from those in previous studies. The debris estimation in this study has better accuracy than previous models in nationwide scale. It can be said that the development of a regional-scale flood debris estimation model will enhance the accuracy of the prediction.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.54 no.2
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• pp.124-137
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• 2018

Due to the decrease in coastal productivity and deterioration in the quality of ecosystem which result from the excessive overfishing of fisheries resources and the environmental pollution, fisheries resources in the Korean waters hit the dangerous level in respect of quantity and quality. In order to manage sustainable and effective fisheries resources, it is necessary to suggest the potential yield (PY) for clarifying available fisheries resources in the Korean waters. So far, however, there have been few studies on the estimation methods for PY in Korea. In addition, there have been no studies on the comparative analysis of the estimation methods and the substantial estimation methods for PY targeted for large marine ecosystem (LME) For the reasonable management of fisheries resources, it is necessary to conduct a comprehensive study on the estimation methods for the PY which combines population dynamics and ecosystem dynamics. To reflect the research need, this study conducts a comparative analysis of estimation methods for the PY in the Korean waters of the East Sea to understand the advantages and disadvantages of each method, and suggests the estimation method which considered both population dynamics and ecosystem dynamics to supplement shortcomings of each method. In this study, the maximum entropy (ME) model of the holistic production method (HPM) is considered to be the most reasonable estimation method due to the high reliability of the estimated parameters. The results of this study are expected to be used as significant basic data to provide indicators and reference points for sustainable and reasonable management of fisheries resources.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.3
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• pp.11-21
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• 2021

In the last few years, there is growing interest in the field of simultaneous equation estimation in finance due to the endogeneity problem caused by measurement errors, simultaneity, or omitted variables. This study aims to discuss the endogeneity problem in corporate financing decisions and investigate the interrelationship of financial decision-making such as investment decision, dividend decision, and external financing decision in Pakistan Stock Exchange (PSX) using two-stage least squares (2SLS) and generalized method of moment (GMM) estimation. The Bruech-Pagan test shows that the data has no heteroskedasticity issue and 2SLS is a better approach in the context of this study as compared to the GMM approach, and internal instruments are also sufficiently strong and valid. The three financial decision-making attributes are not jointly determined, and the dividend is influenced by one-sided investment. In the emerging stock market context, external financing and investment are not inter-related and did not affect each other. The question of whether the simultaneous equation estimation can be useful in the context of the emerging stock markets and newly-growing firms remains unanswered. The inclusive evidence shows that the theoretical link in the emerging stock market is difficult to prove like in developed stock markets.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.5
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• pp.1356-1376
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• 2023

Software effort estimation is one of the most difficult tasks in software development whereas predictability is also of equal importance for strategic management. Accurate prediction of the actual cost that will be incurred in software development can be very beneficial for the strategic management. This study discusses the latest trends in software estimation focusing on analogy-based techniques to show how they have improved the accuracy for software effort estimation. It applies the standard deviation technique to the expected value of analogy-based estimates to improve accuracy. In more than 60 percent cases the applied technique of this study helped in improving the accuracy of software estimation by reducing the Magnitude of Relative Error (MRE). The technique is simple and it calculates the expected value of cost or time and then uses different confidence levels which help in making more accurate commitments to the customers.