• Nuclear Engineering and Technology
• /
• v.48 no.1
• /
• pp.98-113
• /
• 2016

A reactor vessel level monitoring system measures the water level in a reactor during normal operation and abnormal conditions. A drop in the water level can expose nuclear fuel, which may lead to fuel meltdown and radiation spread in accident conditions. A level monitoring system mainly consists of a sensing line and pressure transmitter. Over a period of time boron sediments or other impurities can clog the line which may degrade the accuracy of the monitoring system. The aim of this study is to determine blockage in a sensing line using the energy of the composite signal. An equivalent Pi circuit model is used to simulate blockages in the sensing line and the system's response is examined under different blockage levels. Composite signals obtained from the model and plant's unblocked and blocked channels are decomposed into six levels of details and approximations using a wavelet filter bank. The percentage of energy is calculated at each level for approximations. It is observed that the percentage of energy reduces as the blockage level in the sensing line increases. The results of the model and operational data are well correlated. Thus, in our opinion variation in the energy levels of approximations can be used as an index to determine the presence and degree of blockage in a sensing line.

• The Journal of the Acoustical Society of Korea
• /
• v.20 no.2
• /
• pp.77-85
• /
• 2001

This paper proposes a method of time-scale modification of polyphonic audio signals based on a sinusoidal model. The signals are modeled with sinusoidal component and noise component. A multiresolution filter bank is designed which splits the input signal into six octave-spaced subbands without aliasing and sinusoidal modeling is applied to each subband signal. To alleviate smearing of transients in time-scale modification a dynamic segmentation method is applied to subbands which determines the analysis-synthesis frame size adaptively to fit time-frequency characteristics of the subband signal. For extracting sinusoidal components and calculating their parameters matching pursuit algorithm is applied to each analysis frame of subband signal. In accordance with spectrum analysis a psychoacoustic model implementing the effect of frequency masking is incorporated with matching pursuit to provide a resonable stop condition of iteration and reduce the number of sinusoids. The noise component obtained by subtracting the synthesized signal with sinusoidal components from the original signal is modeled by line-segment model of short time spectrum envelope. For various polyphonic audio signals the result of simulation shows suggested sinusoidal modeling can synthesize original signal without loss of perceptual quality and do more robust and high quality time-scale modification for large scale factor because of representing transients without any perceptual loss.

• The Journal of Information Systems
• /
• v.20 no.1
• /
• pp.107-126
• /
• 2011

Model-based decision support system (DSS) has acted as a crucial role in strengthening the business competitiveness by providing a way of modeling and solving real-world decision problems in a quantitative and scientific manner. It is even more important for trading OTC derivatives, which requires extensive financial-engineering expertise while actively reacting to the continuously changing financial market. This paper proposes a flexible model-based DSS architecture that can support user-friendly interface for executing and analyzing the models and can adapt to the changes of financial market seamlessly. For user-friendliness, we implement the user-interfaces (UIs) using Microsoft Excel, a very widely used spreadsheet program for its great generality and extensibility. Users can utilize the analysis results of DSS or reprocess them for their special needs through the UIs in the form of familiar spreadsheets easily. For adaptiveness to the markets, the proposed architecture is constructed based on the object-oriented concepts, which enables such changes as release of a new financial product can be updated into the system without any delay at the lowest cost. We investigate the practical benefits and limitations of the proposed architecture by a case study on the construction of Model-based Trading Support System (MTSS), performed by a commercial bank in Korea.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.25 no.12
• /
• pp.888-894
• /
• 2015

A new method for the simulation of the vehicle's interior road noise is proposed in the present study. The road noise model can synthesize road noise of a vehicle for varying driving speed within a range. In the proposed method, interior road noise is considered as a stochastic time-series, and is modeled by a nonstationary parametric model via two steps. First, each interior road noise signal, obtained from constant speed driving tests performed within a range of speed, is modeled as an autoregressive model whose parameters are estimated by using a standard method. Finally, the parameters obtained for different driving speeds are interpolated based on the varying driving speed to yield a time-varying autoregressive model. To model a full band road noise, audible frequency range is divided into an octave band using a wavelet filter bank, and the road noise in each octave band is modeled.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2005.05b
• /
• pp.414-418
• /
• 2005

A finite element model is developed for the numerical simulation of bed elevation change in a curved channel. The SU/PG (Streamline-Upwind/Petrov-Galerkin) method is used to solve 2D shallow water equations and the BG (Bubnov-Galerkin) method is used for the Exner equation. For the time derivative terms, the Crank-Nicolson scheme is used. The developed model is a decoupled model in a sense that the bed elevation does not change simultaneously with the flow during the computational time step. The total load formula with is used for the sediment transport model. The slip conditions are described along the lateral boundaries. The effects of gravity force due to geometry change and the secondary flows in a curved channel are considered in the model. For the verification, the model is applied to two laboratory experiments. The first is $140^{\circ}$ bended channel data at Delft Hydraulics Laboratory and the second is $140^{\circ}$ bended channel data at Laboratory of Fluid Mechanics of the Delft University of Technology. The finite element grid is constructed with linear quadrilateral elements. It is found that the computed results are in good agreement with measured data, showing a point bar at the inner bank and a pool at the outer bank.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.33 no.7
• /
• pp.541-551
• /
• 2009

Configuration of the inlet transition square duct (hereinafter referred to as "transition duct") for heat recovery steam generator (hereinafter referred to as "HRSG") in combined cycle power plant is limited by the construction type of HRSG and plant site condition. The main purpose of the present study is to analyze the effect of a variation in turbulent flow pattern by roof slop angle change of transition duct for horizontal HRSG, which is influencing heat flux in heat transfer structure to the finned tube bank. In this study, a computational fluid dynamics(CFD) is applied to predict turbulent flow pattern and comparisons are made to 1/12th scale cold model test data for verification. Re-normalization group theory (RNG) based k-$\epsilon$ turbulent model, which improves the accuracy for rapidly strained flow and swirling flow in comparison with standard k-$\epsilon$ model, is used for the results cited in this study. To reduce the amount of computer resources required for modeling the finned tube bank, a porous media model is used.

• Proceedings of the KIEE Conference
• /
• 2005.07b
• /
• pp.1339-1342
• /
• 2005

This paper presents a simple AC-DC power conditioner for a squirell-cage induction generator(IG) operating under variable shaft speeds. The necessary reactive power for the IG system is supplied by means of a capacitor bank and a voltage-source PWM converter. Using a capacitor bank to transfer the reactive power to the IG under the rated speed and no-load conditions starts the IG operation and reduces the PWM power converter size. A simple control compensating for changes in the electrical loads as well as the variation in speed was developed to regulate the voltages of the IG system by controlling the rotor flux through its reactive and active currents control implementation. This proposed power conditioning scheme can be used efficiently as a wind power generation system where the output voltage of the IG is maintained constant voltage despite the variable frequency and the DC bus voltage of the PWM converter can be used for either DC applications such as battery charging or AC power applications with 60/50 Hz by connecting a stand alone inverter. The experimental and simulated operating performance results of a 5 kW IG scheme at various speeds and leads are presented.

• Asian Journal of Business Environment
• /
• v.10 no.3
• /
• pp.35-42
• /
• 2020

Purpose: Islamic banking products and services have always claimed to be unique from its traditional interest-based counterpart. However, in practice, many Islamic banks are alleged to have drifted away from its paradigm version. The purpose of this study is to gauge the perception of university students in Malaysia towards Islamic banking products. Research design, data and methodology: Data were collected from 250 Malaysian university students. Structural Equation Modeling (SEM) was performed to test proposed hypotheses to identify factors influencing customers' perception toward Islamic banking products. Results: The main finding indicates that most of the respondents are familiar with Islamic banking products and consider Islamic banking products as useful as its conventional counterparts. The regression results show that respondents are less convinced of adherence to Shari'ah, efficiency and helpfulness of existing Islamic banks. Conclusions: This is a cue to the Islamic banks' stakeholders that they need to realign their practices in an ethically responsible way in accordance with Shari'ah if they wish to secure existing customers and attract potential ones. In a competitive banking environment, most banks provide efficient and readily available service; thus, focusing on this as a strategy hardly distinguishes an Islamic bank from an interest-based bank.

• The Journal of Asian Finance, Economics and Business
• /
• v.8 no.9
• /
• pp.201-210
• /
• 2021

A bank's competitive advantage helps in enhancing its ability to maintain a competitive advantage in product consumption, expand the consumption market, and effectively use business factors to maximize economic growth. The research aims to investigate the impact of organizational culture on the sustainable competitive advantage of commercial banks in Vietnam. The study adopts a quantitative research method, through structural equation modeling analysis (SEM). A survey was conducted on 608 participants who are staff at commercial banks in Vietnam. Research results show that organizational culture has both a direct and indirect impact on sustainable competitive advantage through factors of social responsibility and knowledge sharing. Based on these findings, the study gives some recommendations to contribute to the creation, maintenance, and development of sustainable competitive advantages of commercial banks. The findings of this study have shown the importance and impact of organizational culture on many aspects of a bank's sustainable competitive advantage. These are meaningful contributions in both theory and practice to help banks gain more insight into human resources management. The study also raises an issue on the need to care about and develop an organizational culture to bring professionalism, initiative, and fairness in all activities of commercial banks.

• Journal of Distribution Science
• /
• v.21 no.7
• /
• pp.41-50
• /
• 2023

Purpose: The purpose of the research is identified factors influencing the competitiveness of the copper industry in Kazakhstan. Research design, data and methodology: A few studies are dedicated to the analysis in developing countries, particularly Kazakhstan. The algorithm was chosen for research provision: statistical and comparative analysis, correlation, and regression analysis. The data of 1999-2021 obtained from the World Bank, Bureau of National Statistics, National Bank of Kazakhstan. Results: The obtained results demonstrate the trends in the development of the industry since 2000. The development of the copper industry is strongly influenced by the distribution and state of the business environment, economic situation, and trends in the global commodity markets. Conclusions: According to econometric modeling, there is a correlation between the profitability of the copper industry, GDP, copper prices, liquidity, and energy resource prices. Trends in global commodity and energy markets have a significant impact on the state of the industry. Further research should be conducted to include an analysis and forecast of internal factors that may affect the development of the industry, such as copper reserves, condition of fixed assets, government programs, etc. It is also important to examine the correlation with the trends in the development of the global green economy and the revival of the Chinese market.