• Journal of Korea Water Resources Association
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• v.38 no.12 s.161
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• pp.1061-1072
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• 2005

A hydrological grey model is developed to forecast short-term river runoff from the Naju watershed located at upstream of the Youngsan estuary dam in Korea. The runoff of the Naju watershed is measured in real time at the Naju streamflow gauge station, which is a key station for forecasting the upstream inflow and operating the gates of the estuary dam in flood period. The model's governing equation is formulated on the basis of the grey system theory. The model parameters are reparameterized in combination with the grey system parameters and estimated with the annealing-simplex method In conjunction with an objective function, HMLE. To forecast accurately runoff, the fifth order differential equation was adopted as the governing equation of the model in consideration of the statistic values between the observed and forecast runoff. In calibration, RMSE values between the observed and simulated runoff of two and six Hours ahead using the model range from 3.1 to 290.5 $m^{3}/s,\;R^2$ values range from 0.909 to 0.999. In verification, RMSE values range from 26.4 to 147.4 $m^{3}/s,\;R^2$ values range from 0.940 to 0.998, compared to the observed data. In forecasting runoff in real time, the relative error values with lead-time and river stage range from -23.4 to $14.3\%$ and increase as the lead time increases. The results in this study demonstrate that the proposed model can reasonably and efficiently forecast runoff for one to six Hours ahead.

• Journal of the Korean Institute of Gas
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• v.13 no.1
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• pp.14-20
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• 2009

As the consumption of LNG has increased, the capacity and number of LNG facilities are getting bigger and bigger. Such circumstances supports the need for a dedicated risk analysis model to help review and check major issues of the safer construction and operation of LNG storage facilities systematically. Therefore this study suggests an appropriate risk analysis model that enables us to evaluate hazards of LNG storage facilities more easily and systematically, and then to use its result in siting, design and construction stages of the facilities. ill order to develop the model, lots of existing studies and domestic and foreign codes and standards were fully reviewed and a series of case studies also were carried out. The suggested model consists of 4-stage evaluations: in selecting a site, in determining a layout, in designing and constructing the facilities, and in operating them. This model also suggests the weather condition necessary for estimating the consequence of accident-scenarios, and the easy, systematic approach to the analysis of their probability. We expect that the model may help secure LNG storage facilities' inherent safety in determining their site and layout.

• 대한공업교육학회지
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• v.36 no.2
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• pp.239-256
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• 2011

The purpose of this study is to deduce the effective improvement plans of engineering education system and to provide the base materials by analyzing satisfaction and problems in the perception survey of stakeholders related in engineering education system including Engineering Education Accreditation System. Engineering education system improvement plans from the results of study are as follows. First, government and university should provide more financial support to the college in order to improve education environment such as laboratories and equipment. Second, in order to improve links among engineering education stakeholders, student-professor, student-faculty, and colleges should operate effective mentoring program and consultation plan. Third, according to service quality evaluation, colleges need to give rewards to distinguished faculties for their outstanding work and build up job training about services in order to enhance satisfaction of students and professors, Also, business related to Engineering Education Accreditation System should be simplified and needs to increase the number of workers exclusively responsible for this work. Forth, in order to enhance comprehension of learning outcome and outcome of Engineering Education Accreditation System, it is necessary to improve Engineering education innovation center's status, to establish active systematic promotion system and to operate engineering education evaluation expert committee such as 'Engineering education system evaluation council'. Fifth, because of the stakeholder's shortage of benefits and tiredness accumulation, the issue of effectiveness in engineering education institutions has raised controversy. Thus, engineering education institutions needs to take measure necessary. Moreover, engineering education improvements should be improved by reflecting opinions from professors, faculties and students who are practically planning, operating and participating engineering education programs.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.1
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• pp.9-18
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• 2010

This research surveys actual conditions in order to examine the lighting environments of the elderly's residential 50 households. The results is as following. First, The elderly indicated that they felt the living room and the kitchen are usual degree, dark only in bedrooms and rest rooms of brightness. And about satisfactory degree of residential illumination is being above of usual Satisfaction. Second, Problems of lighting environments of elderly's houses were brightness and management, when lighting environmental reconstruct, considered brightness and equipment superannuation, and they want the focus on brightness in the reconstruction. Third. Operating method of lighting was used almost overall lighting in bedroom and bathroom, overall lighting and part lighting are used together in kitchens. The living room has a lot of cases which uses only a general illumination, but the cases which overall lighting and part lighting are used together has occupied 40[%]. Fourth, An average Illuminance of the bedroom is 104.17[lx], an average unifonnity ratio is 60.22[%]. The livingroom's average is 116.15[lx], 51.48[%]. The sink's average is 236.40[lx], the table average is 160.73[lx] in the kitchen. The washstand's average is 109.81[lx], the chamber's average pot is 74.33[lx] in the bathroom. These results are generally darker than the standard.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.8
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• pp.105-114
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• 2018

Membrane fouling in EC-MBR (Electro-Coagulation aided Membrane Bio-Reactor) processes was evaluated according to the operating parameters, such as current density and contact time. In addition, the fouling mechanism was investigated. Compared to the control (i.e., no electro-coagulation), membrane fouling for filtration of the activated sludge suspension after electro-coagulation was reduced significantly. Membrane fouling was improved further when the contact time was doubled under a low current density of $2.5A/m^2$. On the other hand, membrane fouling was not mitigated further, as expected, even though the contact time was doubled from 12 to 24 hr. at a current density of $10A/m^2$. This indicates that the overall decrease in membrane fouling is a function of the product of the current density and contact time. The particle size of the activated sludge flocs after electro-coagulation was changed slightly, which means that the membrane fouling reduction was not attributed to a larger particle size resulting from electro-coagulation. The experimental confirmed that the dynamic membrane made from aluminum hydroxide, Al(OH)3, and/or aluminum phosphate, Al(PO4), which had been formed during the electro-coagulation, played a key role on the reduction of membrane fouling. The dynamic membrane prevents the particles in the feed solution from deposition to the membrane pores and cake layers. Dynamic membrane formation as a result of electro-coagulation plays a critical role in the mitigation of membrane fouling in EC-MBR.

• Environmental and Resource Economics Review
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• v.20 no.3
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• pp.595-628
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• 2011

This study investigates the issues and suggests reform measures in applying CV methods to the Korea Development Institute's (KDI's) Preliminary Feasibility Test (PFT) of public projects. Most public projects on culture, science and environment evaluated under the PFT system belong to the category of "nonstandard" projects whose outputs are non-marketed, and CV is currently the main tool used for their benefit estimation. A careful discussion and investigation is recommended for the selection of target population, payment vehicle, and number of payment times. Operating expert reviews, focus group interviews, and pre-tests is highly recommended to reduce the potential bias involved in the CV studies. A single or double bounded dichotomous choice format is the most popular design of questionnaire, but we identify several undissolved issues in designing and implementing the format. Some other forms of inducing WTPs may still deserve our consideration. Various specifications of the WTP function need to be tried and tested based on their stability, in particular. Employing a nonparametric approach is also recommended. Treatments of 0 or negative WTPs and protest bids are shown to be the most serious issues that affect the estimation results significantly. We review diverse measures of handling those issues and summarize their advantages and shortcomings.

• Journal of Astronomy and Space Sciences
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• v.22 no.3
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• pp.283-292
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• 2005

Ionosphere is deeply coupled to the space environment and introduces the perturbations to radio signal because of its electromagnetic characteristics. Therefore, the status of ionosphere can be estimated by analyzing the GPS signal errors which are penetrating the ionosphere and it can be the key to understand the global circulation and change in the upper atmosphere, and the characteristics of space weather. We used 9 GPS Continuously Operating Reference Stations (CORS), which have been operated by Korea Astronomy and Space Science Institute (KASI) , to determine the high precision of Total Electron Content (TEC) and the pseudorange data which is phase-leveled by a linear combination with carrier phase to reduce the inherent noise. We developed the method to model a regional ionosphere with grid form and its results over South Korea with $0.25^{\circ}\;by\;0.25^{\circ}$ spatial resolution. To improve the precision of ionosphere's TEC value, we applied IDW (Inverse Distance Weight) and Kalman Filtering method. The regional ionospheric model developed by this research was compared with GIMs (Global Ionosphere Maps) preduced by Ionosphere Working Group for 8 days and the results show $3\~4$ TECU difference in RMS values.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.2
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• pp.117-124
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• 2018

This paper describes the localization development of an axial fan for KM-SAM multi-function radar. The multi-function radar, which is constantly affected by the external environment, is a key instrument for detecting and tracking low and medium altitude threat targets. Operating this equipment smoothly requires a fan for controlling the internal temperature and humidity. Presently, all such fans are imported. To solve these problems, localization development research was proposed. The development of localization includes analysis of requirements through review of related technical reports such as original equipment and system equipment specification, prototype design, and verification of design requirement through performance test and environmental test. The study results are described. The blower consisted of an axial fan with guide vanes and the motor was designed to generate a maximum airflow of 970 CFM and a wind pressure of 4.8 IWG. Six prototypes were manufactured for performance evaluation. In addition, for reliable data acquisition, AC power supply, fan performance tester and data acquisition equipment were designed and tested. All prototypes were verified as having design requirements equal to or better than those of imports.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.7
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• pp.375-383
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• 2018

This study was carried out to grasp the economic effects of the social welfare foundation by establishing and operating it. For this purpose, the effects of the social welfare law of Daegu Metropolitan City on the regional economy were analyzed using the input-output analysis model. As a result, the effects of GDP was 43,445 billion won, the total value-added effect was 1,940 billion won, and the total employment inducement effect was 37,411. Based on these results, the future direction of the social welfare corporation is suggested as follows. First, it is necessary to shift the perception of consumer-oriented welfare toward welfare that contributes to the activation of the local economy. Second, efforts should be made to continuously expand employment linked to social welfare services, to create an environment where jobs can be created from a long-term perspective, and to establish a separate support system. Third, the value-added created by the social welfare foundation should be newly recognized and sought to be expanded in various fields. Fourth, efforts should be made to secure the legitimacy of social service provision and ensure accountability by appropriately promoting the economic ripple effects of social welfare foundation to the local community.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.7
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• pp.1-8
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• 2018

This paper describes new communication methods for transmitting torque commands between the vehicle controller that determines the amount of power generation in a range-extended electric vehicle and the engine controller that performs it. Generally, vehicles use CAN communication, but in this case, the hardware and software of the existing engine controller must be modified. For this reason, it is not easy to apply CAN communication to small and medium sized automotive reorganize companies. Therefore, this research presents a pin-pin communication method for applying the existing mass produced engine controller to range-extended electric vehicles. The pin-pin communication method converts the driver's demand torque control map inside an mass produced engine controller into a virtual accelerator opening position according to the target speed and target torque of the engine, and converts this to a voltage signal for the existing mass produced engine controller to recognize it. The virtual accelerator opening positions are mounted in the form of a control map in the vehicle controller through the reverse conversion process in an offline environment and are determined by the engine generating power requirements and engine optimal operating point algorithm. These algorithms and signal conversion circuits for engine torque transmission have been mounted on the vehicle controller to conduct the virtual accelerator opening position conversion process according to the engine target torque and to establish the virtual accelerator voltage signal using the signal converter.