• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.3
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• pp.50-57
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• 2003

In the paper, the design and evaluation of a helicopter trajectory tracking controller are presented. The control algorithm is implemented using the feedback linearization technique and the two time-scale separation architecture. In addition, and on-line adaptive architecture that employs a neural network compensating the model inversion error caused by the deficiency of full knowledge of helicopter dynamic is applied to augment the attitude control system. Trajectory tracking performance of the control system in evaluated using modified TMAN simulation program representing as Apache helicopter. It is show that the on-line neural network in an adaptive control architecture is very effective in dealing with the performance depreciation problem of the trajectory tracking control caused by insufficient information of dynamics.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.67 no.1
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• pp.21-26
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• 2018

Due to the international environmental regulations and changes in policies, the demand for generators using the renewable energy is increasing. However, renewable energy generators with intermittent output characteristics such as solar and wind power generators, need the buffer facilities such as ESS during system operations. However, because of low price competitiveness in energy storage system, it is difficult to operate the renewable energy generator with ESS. Therefore, the government has recently proposed a policy to compensate the REC for renewable energy system with ESS. For all this, since the initial cost of the ESS is high, it is the most important to calculate and operate the optimal capacity of the ESS through an economic analysis. In this paper, we proposed the method of calculation the optimal capacity of ESS and analyzed economic feasibility of renewable energy system using the ESS according to depreciation in ESS price.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.8
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• pp.41-49
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• 2020

This study investigates the short-run and long-run causal behavior of the Philippine stock market index volatility under vector error correction environment. The variables were tested first for stationarity and then long-run equilibrium relationship. Moreover, an impulse response function was estimated to examine the extent of innovations in the independent variables in explaining the Philippine stock market index volatility. The results reveal that the volatility of the Philippine stock market index exhibit long-run equilibrium relationship with Peso-Dollar exchange rate, London Interbank Offered Rate, and crude oil prices. The short-run dynamics-based VECM estimates indicate that in the short-run, increases (i.e., depreciation) in Peso-Dollar exchange rate cause PSEI volatility to increase. As for the London Interbank Offered Rate, it causes increases in PSEI volatility in the short-run. The adjustment coefficients used with the long-run dynamics validates the presence of unidirectional causal long-run relationship from Peso-Dollar exchange rate, London Interbank Offered Rate, and crude oil prices to PSEI volatility, and bidirectional causal long-run relationship between PSEI volatility and London Interbank Offered Rate. The impulse response functions developed within the VECM framework demonstrate the positive and negative reactions of PSEI volatility to unanticipated Peso-Dollar exchange rate, London Interbank Offered Rate, and crude oil price shocks.

• Korea Journal of Hospital Management
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• v.14 no.2
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• pp.60-74
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• 2009

This study purports to verify managerial effectiveness of the integrated delivery system(IDS) of Japanese health care institutions through comparing the managerial performance between hospital groups providing with both acute and nursing care and those with acute care only. Data on the managerial performance of 697 hospitals providing with nursing care together and 819 hospitals providing with acute care only were collected from Japanese Central Social Insurance Medical Councils 2001, 2003, 2005, and were analyzed using mean comparison test(t-test) between the two groups. The results revealed that there were significant differences between the two groups in such indicators as ratio of material cost, labor cost, depreciation rate, total margin, operating margin, average number of outpatient per day, average revenue of an inpatient per day, total amount of labor cost, gross revenue per employee, and labor productivity. However, we could not find out any consistent evidence which support the effect of integrated delivery system on the hospital managerial performance. Further discussion was made on the limitation of the study and future research agenda relevant to the topic.

• East Asian Journal of Business Economics (EAJBE)
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• v.4 no.4
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• pp.1-7
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• 2016

This paper has studied the impacts of the exchange rate, government debt as a percent of GDP and other relevant macroeconomic variables on aggregate output in the Philippines. A simultaneous-equation model consisting of aggregate demand and short-run aggregate supply is applied. The dummy variable technique is employed to detect whether the slope and intercept of the real effective exchange rate may have changed. Real depreciation during 1998.Q1 - 2006.Q3, real appreciation during 2006.Q4 - 2016.Q1, a lower domestic debt as a percent of GDP, a lower real interest rate, a higher stock price or a higher lagged real oil price would raise aggregate output. Recent trends of real peso appreciation, declining domestic debt as a percent of GDP, lower real interest rates, and rising stock prices are in line with the empirical results and would promote economic growth. The authorities may need to continue to pursue fiscal prudence and maintain a stronger peso as the positive effect of real appreciation dominates its negative effect in recent years.

• Journal of Fisheries and Marine Sciences Education
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• v.28 no.6
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• pp.1629-1639
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• 2016

This study is to estimate the production efficiency of abalone aquaculture and to find its determinants utilizing the survey data of operating expenses in 2015. The first part of the analysis applied both DEA and Super-DEA for the estimation of efficiency of each aquaculture household as DMU. We used wages, feeding costs and area as inputs and annual profits and sales as outputs of the model. The second part of the study applied both Tobit and OLS for the identification of determinants of the efficiency. We investigated cost-ratio, depreciation costs, careers, value of living seeds, cleaning costs of farming ground and a ratio of 1 and 2 year-old abalone at shipment as potential determinants. The estimation results show us that the average technical efficiency, pure technical efficiency, and scale efficiency score turn out to be 72%, 81% and 85% respectively. The Super-BCC and Super-CCR models reveal their average efficiency scores as 81% and 80%. All of the variables used to identify the determinants of the efficiency. The study results suggests that the production efficiency can be improved by cleaning farming ground and hence lowering the death rate of seeds.

• Journal of Agricultural Extension & Community Development
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• v.23 no.2
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• pp.145-156
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• 2016

The purpose of this study is to analyze the farms growing domestic kiwi fruit 'Gold' on their management performance and efficiency in order to reduce the risks involved with introducing new kind of crops for growing, and suggest improvements. First, the result of analysis showed that domestic kiwi fruit 'Gold' growers' income were higher than the average growers due to the fruit's high unit price and productivity. Second, the analysis of management efficiency resulted in scale efficiency having greater impact on inefficiency rather than pure technical efficiency. As for the analysis of technical efficiency, the depreciation costs of agricultural facilities had the greatest influence on its inefficiency. Third, inefficient farms put in excessive inputs across the board, while labor costs(self labor cost + hired labor cost) were the largest factor of optimal inputs according to the models of technical efficiency and pure technical efficiency. Fourth, because of greater reliance on mechanical tools from rising labor costs, there's a need for individual farms to avoid buying farming equipments and instead share the equipments of nearby farms and agricultural cooperatives, or start renting agricultural machines from companies.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.32 no.4
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• pp.184-191
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• 2009

In a technological driven environment, a depreciation estimate which is based on traditional life analysis results in a decelerated rate of capital recovery. This time pattern of technological growths models needs to be incorporated into life analysis framework especially in those industries experiencing fast technological changes. The approximation technique for calculating the variance can be applied to the six growth models that were selected by the degree of skewness and the transformation of the functions. For the Pearl growth model, the Gompertz growth model, and the Weibull growth model, the errors have zero mean and a constant variance over time. However, transformed models like the linearized Fisher-Pry model, the linearized Gompertz growth model, and the linearized Weibull growth model have increasing variance from zero to that point at which inflection occurs. It can be recommended that if the variance of error over time is increasing, then a transformation of observed data is appropriate.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.8 no.3
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• pp.23-27
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• 2012

A seawater pumps in the nuclear power plant is responsible for providing cooling water to other components all the time. Because of the depreciation, the seawater pump with current impeller consumes too much power for maintaining the total head. Therefore the objective of this study is to reduce power with maintaining certain the total head by cutting the current impeller. By using a commercial CFD code, FLUENT, the overall performance of seawater pump with current and modified impeller was simulated. Also Affinity law was applied at pumps with various impeller diameter and evaluated the validity of the affinity law. The numerical results show that the pump efficiency is quite irrelevant to the diameters of the impellers and the pump efficiency becomes worse over the designed flow rate. And affinity law result and numerical one show good agreements at small change of impeller diameter. One of the impeller diameters was decided to modify and was applied to the nuclear power plant with the numerical study above.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.1
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• pp.61-69
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• 2021

The aim of this paper is to empirically investigate whether and how domestic currency valuation is related to firm-level export competitiveness and profitability by using the unique firm-specific dataset on Bangladeshi nonfinancial firms which have been listed continuously from 2010 to 2018. To achieve the aim of this paper, 63 exporting firms are extracted from a total of 125 firms which have been continuously listed during 2010-2018 and used as the final sample firms. The Pedroni cointegration test reveals that export and import prices of the exporting firms are cointegrated in the short-run as well as long-run. The panel dynamic ordinary least square (DOLS) analysis finds that a firm's export competitiveness is maintained by high import inputs even in the presence of depreciation of Bangladeshi currency against the US dollar. Finally, the DuPont analysis finds that the depreciated Bangladeshi currency enhances an exporter's profitability. Conclusions based on the findings are consistent regardless of exchange rate types, such as, real bilateral exchange rate and nominal or real effective exchange rate indexes. Consequently, the firm-level findings of this investigation suggest that undervalution of home currency is essential for Bangaldesh which is one of the frontier markets in South Asia whose exporting firms are mostly price followers in global markets.