• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2006.05a
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• pp.315-320
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• 2006

This paper presents speed control of IPMSM drive using neural network(NN) PI controller. In general, PI controller in computer numerically controlled machine process fixed gain. They may perform well under some operating conditions, but not all. To increase the robustness of fixed gain PI controller, NNPI controller proposes a new method based neural network. NNPI controller is developed to minimize overshoot, rise time and settling time following sudden parameter changes such as speed, load torque and inertia. Also, this paper is proposed speed control of IPMSM using neural network and estimation of speed using artificial neural network(ANN) controller. The back propagation neural network technique is used to provide a real time adaptive estimation of the motor speed. The results on a speed controller of IPMSM are presented to show the effectiveness of the proposed gain tuner. And this controller is better than the fired gains one in terms of robustness, even under great variations of operating conditions and load disturbance.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.375-378
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• 2007

In these days, Korea Railway apply simple catenary system to general lines and high speed lines of Korea Electric Railway. Circulation Current in catenary system frequently bring undesirable consequences. Namely, the Connector wire has many problems according to a flow of excessive circulation (or traction current) and a sudden rise of temperature on catenary when electric car or locomotive is running in high speed. The occurrence of events by the load increasement do considerable damages to peoples, organizations and systems. On a case by case accidents, the reeltype protective cover as part of various methods has some problems. In this project, we proposed the improved changes on the catenary system of a improvement and change of a messenger wire protector, improvement of connector wire's institution angle and of a replacement the connector wire with a dropper. Its tridimensional space limitation dictated the scale of the $32{\times}{\Phi}55$ to be as small as possible. It is easier to install than work by the existing cover on the messenger wire.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1453-1455
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• 2005

This paper presents self tuning PI controller of IPMSM drive using neural network. Self tuning PI controller is developed to minimize overshoot, rise time and settling time following sudden parameter changes such as speed, load torque and inertia. Also, this paper is proposed speed control of IPMSM using neural network and estimation of speed using artificial neural network(ANN) controller. The results on a speed controller of IPMSM are presented to show the effectiveness of the proposed gain tuner. And this controller is better than the fixed gains one in terms of robustness, even under great variations of operating conditions and load disturbance.

• Plant Journal
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• v.4 no.4
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• pp.71-77
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• 2008

The sulfur oxides is one of important materials to come about air pollution at thermal plant consuming fossil fuel. The several flue gas desulfurization equipments are installed and operated to decrease sulfur oxides. The flue gas desulfurization of our thermal plant is designed for optimizing flue gas desulfurization technical development and research by Korea Electric Power Research Institute. We operate this desulfurization equipment. Now, our country imports nearly 97 percentage of the energy source and competes with the world for the energy because of the sudden rise of raw materials cost. The fuel cost decrease of power plants is the most important factor of the operation. The fuel used in the experiment is the domestic anthracite from Kangwon Taeback and the bituminous coal from Taldinsky Mine in Russia. This Study is experimental investigations of desulfurization characteristics for domestic anthracite power plant by increasing bituminous coal. We surveyed possible parameters and conducted the performance about desulfurization equipment in Yong Dong thermal power plant.

• IEMEK Journal of Embedded Systems and Applications
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• v.18 no.3
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• pp.133-139
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• 2023

This paper proposes a two-stage Water Shield Automation System (WSAS) to predict the possibility of river overflow and vehicle flooding due to sudden rainfall. The WSAS uses a two-stage Deep Neural Network (DNN) model. First, a river overflow prediction module is designed with LSTM to decide whether the river is flooded by predicting the river's water level rise. Second, a vehicle flooding prediction module predicts flooding of underground parking lots by detecting flooded tires with YOLOv5 from CCTV images. Finally, the WSAS automatically installs the water barrier whenever the river overflow and vehicle flooding events happen in the underground parking lots. The only constraint to implementing is that collecting training data for flooded vehicle tires is challenging. This paper exploits the Image C&S data augmentation technique to synthesize flooded tire images. Experimental results validate the superiority of WSAS by showing that the river overflow prediction module can reduce RMSE by three times compared with the previous method, and the vehicle flooding detection module can increase mAP by 20% compared with the naive detection method, respectively.

• Applied Biological Chemistry
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• v.14 no.1
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• pp.35-41
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• 1971

Changes in fatty substance of hot pepper fruit during the after-ripening period were studied for both neutral and polar fatty substance. The results obtained from these studies are tabulated as follows; 1. Total fatty substance decreased as the after-ripening proceeded, while neutral fatty substance was least during the climacteric period. Polar fatty substance showed sudden drop in the amount during the post-climacteric period. 2. Fatty acid composition in neutral fatty substance showed that there is decrease in linoleic acid during the post-climacteric period, and in myristic acid and oleic acid respectively during the climacteric period. Stearic acid contents also drops sharply as after-ripening proceeds. 3. Value for saturates to unsaturates in and the amount of neutral fatty substance became least during the climacteric period, indicating that there is relationship between metabolism of neutral fats and climacteric rise. 4. Fatty acid composition of polar fatty substance showed that there is decrease in linoleic acid when after-ripening takes place whereas linolenic acid increases. These became reverse in the amounts after the climacteric period, suggesting that these changes may be useful to indicate true maturity of the fruits.

• Korean Journal of Construction Engineering and Management
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• v.12 no.2
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• pp.111-120
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• 2011

High-rise buildings have recently increased over the residential, commercial and office facilities, thus an understanding of construction cost for high-rise building projects has been a fundamental issue due to enormous construction cost as well as unpredictable market conditions and fluctuations in the rate of inflation by long-term construction periods of high-rise projects. Especially, recent violent fluctuations of construction material prices add to problems in construction cost forecasting. This research, therefore, develops a time-series model with the Box-Jenkins methodologies and material prices time-series data in Korea in order to forecast future trends of unit prices of required materials. BIM (Building Information Modeling) approaches are also used to analyze injection time of construction resources and to conduct quantity takeoff so that total material price can be forecasted. Comparative analysis of Predictability of tentative ARIMA (Autoregressive Integrated Moving Average) models was conducted to determine optimal time-series model for forecasting future price trends. Proposed BIM based time series forecasting model can help to deal with sudden changes in economic conditions by estimating future material prices.

• Journal of the Korean Institute of Gas
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• v.23 no.6
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• pp.1-7
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• 2019

Most oil refineries and chemical plants have flare systems designed to mitigate pressure rises in process facilities in case of emergencies that require the release of large amounts of gas due to sudden process shutdowns such as power outages. However, the rise of the flame of the flare system causes civil complaints from residents around the factory due to visible pollution, and economic loss occurs in the company, which requires constant management. In this study, two items were diagnosed and analyzed in order to derive the optimal operation method of flare system. First, to detect the cause of the rise in flame height, the acoustic leak detector was used to check gas leaks in safety valves and pressure control valves. Second, to identify the cause of flame instability, the pulsation phenomenon was diagnosed through the CFD simulation and modeling experiments of the sealing drum. By confirming the leak at 4.3% of the safety valve and 10% of the pressure control valve, the cause of abnormal sparking was derived. The information presented in this study can be easily applied to any company that has a flare system, and is expected to prevent complaints and product loss.

• Journal of the Korea Society of Computer and Information
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• v.28 no.8
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• pp.175-186
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• 2023

In this paper, we aim to build a gentrification analysis model and examine its characteristics, focusing on the point at which rents rose sharply alongside the recovery of commercial districts after the gradual resumption of daily life. Recently, in Korea, the influence of social distancing measures after the pandemic has led to the formation of small-scale commercial districts, known as 'hot places', rather than large-scale ones. These hot places have gained popularity by leveraging various media and social networking services to attract customers effectively. As a result, with an increase in the floating population, commercial districts have become active, leading to a rapid surge in rents. However, for small business owners, coping with the sudden rise in rent even with increased sales can lead to gentrification, where they might be forced to leave the area. Therefore, in this study, we seek to analyze the periods before and after by identifying points where rents rise sharply as commercial districts experience revitalization. Firstly, we collect text data to explore topics related to gentrification, utilizing LDA topic modeling. Based on this, we gather data at the commercial district level and build a gentrification analysis model to examine its characteristics. We hope that the analysis of gentrification through this model during a time when commercial districts are being revitalized after facing challenges due to the pandemic can contribute to policies supporting small businesses.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.9 no.1
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• pp.1-13
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• 2006

The recent environmental protection issue has diminished the supply of sand for soft ground improvements so much that the prices of sand have shown a sudden rise. Plastic material is one of substitutes for sand material, but plastic is nonperishable and doubtable if it has potential environmental hormone disrupting substances. Moderate-priced natural fiber drain board made with coconut coir and jute filter are in the spotlight recently as an alternative material for sand and plastic drain board etc. Natural fiber drain has not only competitive price but also a characteristic of assimilation into the soils after finishing of its own function. Discharge capacity of the fiber drain board evaluated by triaxial type discharge capacity test was relatively lower than that of plastic drain board. Nevertheless, settlement and pore pressure dissipation behaviors of the fiber drain board and the plastic drain board which were installed in the clayey soil during the composite discharge capacity test were almost similar. It was also found that biodegradation of the fiber drain board was in progress until 18 month after installation in the clayey soil, but they had still enough engineering properties to use at field.