• Journal of the Korean Solar Energy Society
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• v.28 no.3
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• pp.45-52
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• 2008

In order to clarify characteristics of variation in wind energy over a long-term period, an investigation was carried out at Seoguang site on Jeju island. The wind data for 10 years from Automatic Weather System (AWS) were analyzed for each year. The variation in the annual energy production (AEP) for the 2 MW wind turbine was estimated through statistical work. The result shows that the range of the yearly average wind speed at 15 m above ground level for 10 years was from -22.6% to +13.7%, which is wider range than that in Japan. The coefficient of variation for the AEP was 22.7%, which is about twice of that for the yearly average wind speed. Therefore, for estimating the wind energy potential accurately at a given site, the wind data should be analyzed over a long-term period based on the data from the meteorological station.

• Journal of the Earthquake Engineering Society of Korea
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• v.7 no.2
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• pp.39-48
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• 2003

This paper present a summary of the results of statistical study of the ductility factor which is key component of response modification factor(R). To compute the ductility factor, a group of 1,860 ground motions recorded from various earthquake was considered. Based on the local site conditions at the recording station, ground motions were classified into four groups according to average shear wave velocity. Inleastic spectrum were computed for elastic perfectly plastic SDOF systems undergoing different level of inelastic deformation and period. Ductility factors were calculated by deviding elastic response spectrum by inelastic response spectrum. The influence f displacement ductility ratio, site condition, magnitude and epicentral distance on ductility factors were studied. The coefficient of variation was computed to evaluated the dispersion of ductility factors as the defined ratio of the standard deviation to the mean.

• Journal of the Earthquake Engineering Society of Korea
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• v.13 no.3
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• pp.29-38
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• 2009

n the event of an earthquake, additional stresses can occur in the continuous welded rails (CWR) of High-speed railway (HSR) bridges due to relative displacements at expansion joints, and this stress can cause derailment. The amplification of ground motion occurs as a result of site effects, and this is pronounced at the site of a soft surface soil layer and of a rigid surface soil layer over a soft one. As a result, the amplified ground motion leads to an amplified seismic response in HSR bridges. A change in bridge pier height affects the seismic behavior of the bridge. A HSR bridge with gravel ballast tracks will show different dynamic behavior during an earthquake than one with concrete ballast tracks. The seismic responses of HSR bridges and their CWR are analyzed considering the derailment-inducing factors.

• Industrial Engineering and Management Systems
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• v.8 no.1
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• pp.37-46
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• 2009

Patient safety has become a growing concern in health care. The U.S. Institute of Medicine (IOM) report "To Err Is Human: Building a Safer Health System" in 1999 included estimations that medical error is the eighth leading cause of death in the United States and results in up to 100,000 deaths annually. However, many adverse events and errors occur in surgical practice. Within all kinds of surgical adverse events, wrong-side/wrong-site, wrong-procedure, and wrong-patient adverse events are the most devastating, unacceptable, and often result in litigation. Much literature claims that systems must be put in place to render it essentially impossible or at least extremely difficult for human error to cause harm to patients. Hence, this research aims to develop a prototype system based on active RFID that detects and prevents errors in the OR. To fully comprehend the operating room (OR) process, multiple rounds of on site discussions were conducted. IDEF0 models were subsequently constructed for identifying the opportunity of improvement and performing before-after analysis. Based on the analysis, the architecture of the proposed RFID-based OR system was developed. An on-site survey conducted subsequently for better understanding the hardware requirement will then be illustrated. Finally, an RFID-enhanced system based on both the proposed architecture and test results was developed for gaining better control and improving the safety level of the surgical operations.

• Earthquakes and Structures
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• v.9 no.5
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• pp.983-997
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• 2015

This research evaluates the soil conditions for seismic stations situated in Romania using the horizontal-to-vertical spectral ratio (HVSR). The strong ground motion database assembled for this study consists of 179 analogue and digital strong ground motion recordings from four intermediate-depth Vrancea seismic events with $M_w{\geq}6.0$. In the first step of the analysis, the influence of the earthquake magnitude and source-to-site distance on the H/V curves is evaluated. Significant influences from both the earthquake magnitude and hypocentral distance are found especially for soil class A sites. Next, a site classification method proposed in the literature is applied for each seismic station and the soil classes are compared with those obtained from borehole data and from the topographic slope method. In addition, the success and error rates of this method are computed and compared with other studies from the literature. A more in-depth analysis of the H/V results is performed using data from seismic stations in Bucharest and a comparison of the free-field and borehole H/V curves is done for three seismic stations. The results show large differences between the free-field and the borehole curves. As a conclusion, the results from this study represent an intermediary step in the evaluation of the soil conditions for seismic stations in Romania and the need to perform more detailed soil classification analysis is highly emphasized.

• International Journal of Fluid Machinery and Systems
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• v.7 no.2
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• pp.68-79
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• 2014

The type of turbine developed is based on the very low head of water potential source for the electric power production. The area of research is focused for the axial water turbine that can be applied at the simple site open channel with has a very low cost and environmental impact compared to the conventional hydro installation. High efficiency of axial turbine which applied to the very low potential head will made this type of turbine can be used at wider potential site. Existing irrigation weir and river area will be the perfect site for this turbine. This paper will compare the effects of the variation of swirl velocity criterion during the design of the blade of guide vane and rotor of the turbine. Effects of the swirl velocity criterion is wider known as a vortex conditions (free vortex, force vortex and swirl velocity constant), and the free vortex is the very popular condition that applied by most of turbine designer, therefore will be interesting to do a comparison against other criterion. ANSYS Fluent will be used for simulation and to determine the predictive performance obtained by each of design criteria.

• Korean Journal of Metals and Materials
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• v.46 no.12
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• pp.830-834
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• 2008

NiSi is currently being employed in 45 nm CMOS devices as a contact material. We employed a first principles calculation to understand the movements of atoms when Co, Pd, and Pt were added to tetragonal-NiSi on Si (001). The Ni atoms in the tetragonal-NiSi/Si (001) favored away from the original positions along positive c-direction in a systematic way during the energy minimization. Two different Ni sites were identified at the interface and the bulk, respectively. The Ni site at the interface farther away from the interface was more favorable for Pd and Pt substitution. Co, however, prafered the bulk site to the interface site, unlike Pd and Pt.

• Journal of the Korea Safety Management & Science
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• v.17 no.3
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• pp.33-44
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• 2015

Domestic plant construction sites have a tendency to become bigger, more various and complicated. Moreover frequency of industrial incident is increasing due to short project period, coexistence work condition and using heavy construction equipment. Installing safety facilities and safety training contribute to prevent incident. But mostly incident happens due to workers' unsafe action and wrong work method. Technically, it is very difficult for us to closely manage workers preventing incident. Therefore, the role of foreman who ordinarily works together with his workers is considered more important. Specific execution plan was drawn through industrial incident statistics from Ministry of Labor and questionnaire survey to interest parties(supervisor, safety staff and foreman). If foreman has raised sense of belonging and responsibility by conducting practical safety training for his workers, manages job site and receives proper compensation for these roles, it will be expected that it fully influences incident decrease.

• Journal of the Korean Society of Safety
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• v.35 no.6
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• pp.1-8
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• 2020

In recent years, hydrogen has received much attention as an alternative energy source to fossil fuels. In order to ensure safety from the increasing number of hydrogen refueling stations, prevention methods have been required. In this regard, this study suggested an approach to reduce the risk of hydrogen refueling station by increasing Safety Integrity Level (SIL) for a Steam Methane Reformer (SMR) in On-Site Hydrogen Refueling Station. The worst scenario in the SMR was selected by HAZOP and the required SIL for the worst scenario was identified by LOPA. To verify the required SIL, the PFDavg.(1/RRF) of Safety Instrumented System (SIS) in SMR was calculated by using realistic failure rate data of SIS. Next, several conditions were tested by varying the sensor redundancy and proof test interval reduction and their effects on risk reduction factor were investigated. Consequently, an improved condition, which were the redundancy of two-out-of-three and the proof test interval of twelve months, achieved the tolerable risk resulting in the magnitude of risk reduction factor ten times greater than that of the baseline condition.

• International Journal of Internet, Broadcasting and Communication
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• v.13 no.3
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• pp.148-154
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• 2021

We propose the AI Smart Factory Model for integrated management of production processes in this paper .It is an integrated platform system for the production of food packaging containers, consisting of a platform system for the main producer, one or more production partner platform systems, and one or more raw material partner platform systems while each subsystem of the three systems consists of an integrated storage server platform that can be expanded infinitely with flexible systems that can extend client PCs and main servers according to size and integrated management of overall raw materials and production-related information. The hardware collects production site information in real time by using various equipment such as PLCs, on-site PCs, barcode printers, and wireless APs at the production site. MES and e-SCM data are stored in the cloud database server to ensure security and high availability of data, and accumulated as big data. It was built based on the project focused on dissemination and diffusion of the smart factory construction, advancement, and easy maintenance system promoted by the Ministry of SMEs and Startups to enhance the competitiveness of small and medium-sized enterprises (SMEs) manufacturing sites while we plan to propose this model in the paper to state funding projects for SMEs.