• Journal of the Korea Society for Simulation
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• v.26 no.4
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• pp.35-41
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• 2017

With the advances in Internet over Things, the demand in diverse electronic devices such as mobile phones and sensors has been rapidly increasing and boosting up the researches on those products. Semiconductor materials, devices, and fabrication processes are becoming more diverse and complicated, which accompanies finding parameters for an optimal fabrication process. In order to find the parameters, a process simulation before fabrication or a real-time process control system during fabrication can be used, but they lack incorporating the feedback from post-fabrication data and compatibility with older equipment. In this research, we have developed an artificial intelligence based simulator, which finds parameters for an optimal process and controls process equipment. In order to apply the control concept to all the equipment in a fabrication sequence, we have developed a prototype for a manipulator which can be installed over an existing buttons and knobs in the equipment and controls the equipment communicating with the AI over the Internet. The AI is based on the deep learning to find process parameters that will produce a device having target electrical characteristics. The proposed simulator can control existing equipment via the Internet to fabricate devices with desired performance and, therefore, it will help engineers to develop new devices efficiently and effectively.

• Journal of Wetlands Research
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• v.18 no.4
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• pp.448-455
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• 2016

Diffuse pollution management in Korea initiated by the Ministry of Environment (MOE) resulted to the construction of pilot facilities termed Best Management Practices (BMPs). Twelve BMPs installed for the diffuse pollution management in the Kyung-An Stream were monitored since 2006. Data on the mass loading, removal efficiency, maintenance activities, etc. were gathered and utilized to conduct the evaluation of long-term performance of BMPs. The financial data such as actual construction, design and maintenance cost were also collected to evaluate the lifecycle cost (LCC) of BMPs. In this study, most of the maintenance activity was focused in the aesthetic maintenance that resulted to the annual maintenance cost of the four BMP types was closely similar ranging from 8,483 $/yr for retention pond to 8,888 $/yr infiltration system. The highest LCC were observed in constructed wetland ($418,324) while vegetated system had the lowest LCC ($210,418). LCC of BMPs was not so high as compared with the conventional treatment facility and sewage treatment plant. On the other hand, the relationship of removal efficiency on unit cost for TSS and TN was significant. This study will be used to design the cost effective BMP for diffuse pollution management and become models for LCC analysis.

• Journal of the Korean Society for Nondestructive Testing
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• v.24 no.5
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• pp.499-507
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• 2004

We have studied tile detection techniques, which can determine the location and the weight of an intruder into infrastructure, by using fiber-optic ROTDR (Rayleigh optical time domain reflectometry) sensor and fiber-optic BOTDA (Brillouin Optical time domain analysis) sensor, which can use an optical fiber longer than that of ROTDR sensor Fiber-optic sensing plates of ROTDR sensor, which arc buried in sand, were prepared to respond the intruder effects. The signal of ROTDR was analyzed to confirm the detection performance. The constructed ROTDR could be used up to 10km at the pulse width of 30ns. The location error was less than 2 m and the weight could be detected as 4 grades, such as 20kgf, 40kgf, 60kgf and 80kgf. Also, fiber optic BOTDA sensor was developed to be able to detect intrusion effect through an optical fiber of tells of kilometers longer than ROTDR sensor. fiber-optic BOTDA sensor was constructed with 1 laser diode and 2 electro-optic modulators. The intrusion detection experiment was peformed by the strain inducing set-up installed on an optical table to simulate all intrusion effect. In the result of this experiment, the intrusion effort was well detected as the distance resolution of 3m through the fiber length of about 4.81km during 1.5 seconds.

• Korean Journal of Construction Engineering and Management
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• v.10 no.4
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• pp.111-118
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• 2009

This study is to analyze the performance of SWH(Solar Water Heating) and GSHP(Ground Source Heat Pump) systems by evaluating their energy efficiency and LCC(Life Cycle Cost) as being applied to the OO hall as a selected building in the Army. The OO hall, used as bathrooms, dining rooms, accommodations and offices, has reinforced concrete structure system with three floors above the ground and one underground, and its total floor area is approximately 2,917$m^2$. Two energy simulations are conducted to predict the yearly cooling and heating energy of the selected building: One is for analysis of an air-conditioning energy consumption using the e-Quest program, and another is for two new-renewable energy facilities as a water heating source using the RETScreen. The installed capacity of two new-renewable energy facilities is determined according to the 5% level of total standard construction cost. As a briefly result, SWH system is more energy-effective than GSHP system. Considering the break-even point, it is expected that SWH can take only 3 years 11 months to pay for itself in savings while the investment of GSHP can be recovered in more than 16 years 6 months.

• Journal of Energy Engineering
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• v.27 no.3
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• pp.1-9
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• 2018

In this study, the outdoor evaluation test was performed to characterize the highly-reflective artificial grass to be used for bifacial photovoltaic (PV) power generation system. The 60-cell n-type Si monofacial and bifacial PV modules were employed, where two types of bifacial modules were equipped with split-type and box-type junction boxes, respectively. The results showed that the split-type junction box improved the rear-side power production and thus energy yield of bifacial module compared to the box-type junction box causing the shadow effect. Highly-reflective artificial grass achieved relatively high albedo of 0.18, and excellent bifacial gain of 33%, compared to conventional artificial grass with an albedo of 0.14-0.15, and bifacial gain of 29-30%.

• Fire Science and Engineering
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• v.26 no.5
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• pp.21-27
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• 2012

A real A real scale fire test was performed in accordance with KS F ISO 9705 test method to investigate the combustion characteristics of glass wool sandwich panels. To do this, six kinds of specimens having different density and thickness were examined. The glass sandwich panels were installed inside the room, which had internal dimensions of 2.4 m wide${\times}3.6m$ deep${\times}2.4m$ high. also, combustion characteristic are determined through the exposure of specimens to flame by the propane gas burner has a capacity of 100 kW (10 minutes) and 300 kW (10 minutes) for total 25 minutes of test time. Results of the real sale fire test, it was found that maximum HRR of each specimen was 333.2~365.5 kW, maximum heat flux was 12.4~12.9 kW/$m^2$ And, maximum internal temperature for all specimens was not over $500^{\circ}C$. During the real scale fire test, flash-over didn't occur and the difference by density and thickness of specimen was not found from the results of HRR, heat flux, and internal temperature measurement.

• International Journal of Highway Engineering
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• v.12 no.3
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• pp.17-26
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• 2010

Maintenance of the roads and bridges is a major issue for all road administrators around the world, and various initiatives are being implemented in each region for the purpose of controlling the ever increasing road maintenance cost while ensuring the safety of the vehicles driving. Efforts for such initiatives have also been made in Asia and initiatives for managing heavy-weight vehicles have recently gained momentum in Korea and Japan. We have developed a technology for unevenly installing bar-shaped sensors (piezo quartz sensors) to enable dynamic axle load measurement at a highly accurate level, and have estimated our measurement accuracy of axle load/gross weight, etc. on an actual road. The measurement accuracy of the axle load/gross weight varies significantly depending on the number of sensors installed. In our implementation, the target accuracy was set to below ${\pm}5%$ for gross weight measurement so that automatic regulation can be applied. We have achieved our target by installing 8-point measurement system. However, to have this technology widely accepted, it was necessary to reduce the system size so that it can be easily implemented. Therefore, we have estimated the relationship between the measurement accuracy and the system size (number of measurement points), and have come up with the proposal of 3-point measurement as an optimum number of measurement points, and have estimated its performance on an actual road. Additionally, we evaluated the relationship between the measurement accuracy and vehicle velocity.

• Membrane Journal
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• v.18 no.2
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• pp.157-167
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• 2008

Removal of organic substances and taste/odor control are ones of the main issues in water supply, resulting in introduction of advanced processes such as ozon/GAC, or PAC. However, raw water quality deteriorates, new pollutants advent, so water quality is not acceptable enough even with those existing advanced processes. In this paper, a new advanced water treatment process using PAC slurry blanket, where PAC particles stay in the basin as slurry blanket, coupled with submerged membranes is introduced. A pilot plant $(80m^3/day)$ was installed to assess the performance of this new process using actual raw water, and DOC was removed higher than 90% in the beginning and $70{\sim}80%$ afterwards, while 2-MIB and geosmin were removed completely. This new process still requires future study on process optimization and long-term assessment, however it seems highly possible to countermeasure as a new advanced process with high removal efficiency.

• Journal of the Korean earth science society
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• v.34 no.6
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• pp.588-601
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• 2013

In geophysics and geophysical exploration fields, we can use information about inclination and azimuth in various ways. These include borehole deviation logging for inversion process, real-time data acquisition system, geophysical monitoring system, and so on. This type of information is also necessarily used in the directional drilling of shale gas fields. We thus need to develop a subminiature, low-powered, multi-functional inclination and azimuth measurement system for geophysical exploration fields. In this paper, to develop real-time measurement system, we adopt the high performance low power Micro Control Unit (made with state-of-the-art Complementary Metal Oxide Semiconductor technology) and newly released Micro Electro Mechanical Systems Attitude Heading Reference System sensors. We present test results on the development of a multifunctional real-time inclination and azimuth measurement system. The developed system has an ultra-slim body so as to be installed in 42mm sonde. Also, this system allows us to acquire data in real-time and to easily expand its application by synchronizing with a depth encoder or Differential Global Positioning System.

• Journal of the Korean Institute of Gas
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• v.15 no.5
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• pp.50-56
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• 2011

A preliminary experimental study of new concept air hybrid engine, which stores compressed air in the tank during braking and re-use it to propel vehicle during crusing or acceleration, was carried out in this study. A single cylinder engine was modified to realize the concept of air hybrid engine. Independent variable valve lift system was adopted in one of the exhaust valves to store the compressed air into the air tank during compression period. An air injector module was installed in the place of spark plug, and the stored compressed air was supplied during the expansion period to realize air motoring mode. For air compression mode, the tank with volume of 30 liter could be charged up to more than 13 bar. By utilizing this stored compressed air, motoring work of 0.41 bar of IMEP(Indicated mean effective pressure) at maximum can be generated at the 800rpm conditions, which is higher than the case of normal idle condition by 1.1 bar of IMEP.