• Economic Analysis
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• v.27 no.3
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• pp.33-60
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• 2021

This study estimates the fiscal multiplier using Input-Output table panel data from year of 2010 to 2018. Considering the endogeneity of the government expenditure, this study uses the share of government expenditure by sector in the initial period as an instrument variable. The estimation from the panel fixed effect instrumental variables model shows that the estimate for the current period of government expenditure is 1.15~1.22 and the estimate for the cumulative multiplier is 1.23~1.32 depending on the method of controlling time trend. Since the general equilibrium effect absorbed by the time-fixed effect in the estimation equation, the estimated multiplier in this study may be different from the multiplier of the economy as a whole. The general equilibrium effect depends on the response of monetary policy, changes in tax policy, and interaction between sectors.

• Journal of the Korea Safety Management & Science
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• v.25 no.4
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• pp.1-13
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• 2023

This study aims to investigate the correlation between the causes of natural disasters and feng shui factors targeting disaster management experts, feng shui experts, and the general public who are interested in feng shui. To this end, it is intended to reveal that the factors of the disaster at Mt. The purpose of this study is to analyze the impact of three factors on disasters: feng shui factors, natural factors, and social factors. To this end, a survey was conducted targeting feng shui experts, disaster management experts, master's and doctoral students in feng shui geography, residents of the Umyeonsan disaster area, and people interested in feng shui geography. 260 copies of the questionnaire were prepared and 248 copies were used for the final analysis. First, in order to analyze the impact of feng shui factors on awareness of disaster occurrence, after controlling for demographic variables, hierarchical multiple regression analysis was conducted to analyze the impact of feng shui factors on awareness of disaster occurrence. Second, as a result of analyzing the effect of natural factors on awareness of disaster occurrence, looking at each independent variable in the second-stage regression analysis. Third, as a result of analyzing the effect of social factors on awareness of disaster occurrence, looking at each independent variable in the second-stage regression analysis. Finally, as a result of the T-test and Anova analysis conducted for discriminant analysis, if the p-value was less than .005, the F value for each group was obtained as a result of the ANOVA analysis on the feng-shui factors

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.15 no.4
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• pp.232-239
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• 2015

Studies on the control of the inverted pendulum type system have been widely reported. This is because it is a typical complex nonlinear system and may be a good model for verifying the performance of a proposed control system. In this paper, we propose the design of some fuzzy logic control (FLC) systems for controlling a Segway-type mobile robot, which is an inverted pendulum type system. We first derive a dynamic model of the Segway-type mobile robot and then analyze it in detail. Next, we propose the design of some FLC systems that have good performance for the control of any nonlinear system. Then, we design two conventional FLC systems for the position and balance control of the Segway-type mobile robot, and we demonstrate their usefulness through simulations. Next, we point out the possibility of simplifying the design process and reducing the computational complexity,, which results from the skew symmetric property of the fuzzy control rule tables. Finally, we design two other FLC systems for position and balance control of the Segway-type mobile robot. These systems have only one input variable in the FLC systems. Furthermore, we observe that they offer similar control performance to that of the conventional two-input FLC systems.

• The Korean Journal of Health Service Management
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• v.9 no.1
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• pp.17-29
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• 2015

This study, an examination of the plan for effective resource management for national university hospitals, was performed to determine the relationship between the effectiveness of patient output by considering input personnel using the DEA model and Management Performance, in which 4 years of data from 12 national university hospitals were analyzed. Among the components of the effectiveness, utilizing properly imput components from the application of VRS(Variable Returns to Scale), the Management Performance of national university hospitals was found to be affirmatively influenced by PTE(Pure Technical Efficiency). Regarding the Management Performance of national university hospitals in their attempts to establish a plan for effective human resource management, the management of patient numbers on the basis of calculation level with input is more recommendable than the controlling of personnel input using patient numbers. Thus, the establishment of a strategy plan for the proper allocation of administrative staff and sickbeds, considering the variation of patient numbers, is suggested.

• Child Health Nursing Research
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• v.24 no.4
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• pp.506-516
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• 2018

Purpose: The purpose of this study was to investigate psychological capital, sense of community and stress in relation to school adjustment and to identify factors influencing school adjustment in middle school students. Methods: This study population consisted of 150 middle school students. Data were analyzed using t-test, analysis of variance, Pearson correlation coefficient, and multiple regression analysis. Results: The mean score for school adjustment in middle school students was 3.68 out of 5 points. School adjustment explained 34% of the variance in sense of community (${\beta}=.39$, p<.001), positive psychological capital (${\beta}=.35$, p<.001), academic performance (${\beta}=.26$, p<.001), and stress (${\beta}=-.21$, p<.001). Conclusion: The results of our research suggest that sense of community is an important variable influencing school adjustment in middle school students. Therefore, to promote school adjustment in middle school students, it is necessary to develop and implement active educational strategies promoting sense of community, positive psychological capital, academic perfomance, and controlling stress.

• Journal of international Conference on Electrical Machines and Systems
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• v.3 no.4
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• pp.367-373
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• 2014

The most common current controller for the Switched Reluctance Motor (SRM) is the hysteresis controller. This method, however, suffers from such drawbacks as variable switching frequency, consequent audible noise and high current ripple. These disadvantages make this controlling method undesirable for many applications. The alternative solution is the PI controller. Since the fixed gain PI current controller can only be optimized for one operating point, and on the other hand, SR motor is highly nonlinear, PI controller gain should be adjusted according to incremental inductance. This paper presents a novel method for PI current controller gain adaptation which is simple and yields a good performance. The proposed controller has been implemented on a test bench using a eZdsp F28335 board. The performance of the current controller has been investigated in both simulation and experimental tests using a four-phase 8/6 4KW SRM drive system.

• ALGAE
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• v.27 no.2
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• pp.115-123
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• 2012

The establishment of algal spores plays an essential role in adult kelp distribution and abundance patterns. Sedimentation is a key variable regulating algal spore settlement and success, possibly controlling species-specific dominance $in$ $situ$. Laboratory experiments were used to determine spore attachment and survival rates of two Alaskan canopy-forming kelps, $Nereocystis$ $luetkeana$ (K. Mertens) Postels & Ruprecht and $Eualaria$ $fistulosa$ (Postels & Ruprecht) M. J. Wynne, to various types of sediment loading. Spore attachment for both species was significantly and similarly affected by three sediment treatments: suspended particles; settled sediment covering the substratum; and smothering of attached spores by settling sediment. Spore attachment decreased by approximately 90% at 420 mg sediment $L^{-1}$, the highest sediment load tested here, under all three treatments for both species. These results suggest that increases in sedimentation may constrain the success of the spore stages, but sediment does not seem to be a likely factor explaining species-specific distribution patterns. However, while sedimentation affected spores of both species similarly, timing of spore release in relation to times of maximum sediment load in the water might differ for different species, possibly explaining kelp species distribution patterns.

• Journal of Korean Society of Water and Wastewater
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• v.28 no.4
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• pp.431-440
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• 2014

The ozonation process has been widely used for drinking water disinfection around the world. Recently, the pressurized ozone contactor, in which the side stream typed ozone injection method is installed, has been applied to water treatment system. In this study, numerical calculations were conducted to compare prototype and screw-type ozone contactors based on hydraulic effectiveness in more details. The prototype ozone contactor was already installed and operated in domestic water treatment plant, and the screw-type is the suggested one for improving ozone contact efficiency installing the screw plate to the prototype. Screw turn numbers of screw plate were changed as 3, 5, 7 and 9, respectively for numerical simulation. The CT(concentration of disinfectant in mg/L times time in minutes) value was considered as one of the options for evaluating disinfection ability. From the results, it could be concluded that the performance of the screw-type is higher than that of the protype contactor by controlling the variable T as the tracer time. Also, Morill index of the screw-type(turn numbers = 5 ) appeared to be lower than the other.

• Journal of Power Electronics
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• v.11 no.2
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• pp.148-155
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• 2011

Direct torque control(DTC) of induction machines is known to offer fast instantaneous torque and flux control with a simple control structure. However, this scheme has two major disadvantageous, namely, a variable inverter switching frequency and a high torque ripple. These problems occur due to the use of hysteresis comparators in conventional DTC schemes, particularly in controlling the output torque. This paper reviews the utilization of constant frequency torque controllers (CFTC) in DTC to solve these problems while retaining the simple control structure of DTC. Some extensions of the work in utilizing a CFTC will be carried out in this paper which can further reduce the torque ripple. This is particularly useful for a system which has a limited/low sampling frequency. The feasibility of a CFTC with an extended carrier frequency in minimizing the torque ripple is verified through experimental results.

• The KIPS Transactions:PartC
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• v.15C no.5
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• pp.367-374
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• 2008

To realize the voice privacy between CDMA mobile phone and PSTN terminal, the voice frames shall be transmitted transparently between the heterogeneous networks. For satisfying this requirement, we propose the method which transmits voice frames using the CDMA circuit data channel in real time. In this paper we analyze the causes of voice delay which occurs during voice transmission using circuit data channel. And in order to overcome this kind of delay, the technique controlling the TCP control flag and the variable audio block construction algorithm according to the vocoder output rate are proposed. As a result of experimenting by applying the proposed method, we confirmed that the transit delay was improved with about average 70%.