• Journal of the Earthquake Engineering Society of Korea
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• v.25 no.6
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• pp.241-249
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• 2021

Communication facilities play an essential role in disaster situations. Therefore, communication facilities need to have structural and functional safety during and after earthquakes. Recently, technology for partial seismic isolation has been increasing to protect data facilities and communication equipment installed in buildings from earthquakes. However, excessive displacement may occur in the seismic isolator during an earthquake due to the resonance between the building and the seismic isolator having long-period characteristics, which may cause overturning and separation of the installed equipment. In this study, analytical and experimental studies were conducted to evaluate the safety of seismic isolators installed in high-rise buildings. It was confirmed that damages might occur in buildings' seismic isolator, with resonance characteristics of less than 1 Hz.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.2192-2197
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• 2005

This paper describes how to diagnose SBR plant equipment using time-series data mining. It shows the equipment diagnostics based upon vibration signals that are acquired from each device for process control. Data transform techniques including two data preprocessing skills and data mining methods were employed in the data analysis. The proposed method is not only suitable for SBR equipment, but is also suitable for other industrial devices. The experimental results performed on a lab-scale SBR plant show a good equipment-management performance.

• Proceedings of the IEEK Conference
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• 2000.07a
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• pp.233-236
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• 2000

A portable equipment that measures a current and voltage waveform of power transmission lines is pro-posed. In the equipment, the current and voltage, respectively, are detected by a loop coil and a capacitor clamped around the power lines. The detected data is transmitted by an FM wave to the receiver on the ground station. Since the receiver is isolated from the power lines, we do not require high potential insulators for the measurement of current and voltage. The proposed equipment is therefore, small-sized, light, and low in the cost of production. Experimental results presented here show that the equipment can monitor the current flowing in single wire over a ground plane and the potential of the wire.

• Journal of the Korean housing association
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• v.9 no.2
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• pp.67-78
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• 1998

Construction equipment noise has caused much annoyance for a number of dwellers in nearby construction field and it has become a very serious issue in our living environment. Therefore, in our country, a practical solution and a better method of reducing construction equipment noise are highly required in construction field. Practical solutions for the construction equipment noise, however, are very difficult to obtain, because of the lack of basic data and insufficient research works. Especially, in order to establish a successful sound isolation plan for piling work noise, which has high sound pressure level, the characteristics of the impact noise should be closely monitored and analyzed. This study attempts to survey the characteristics of attenuation and propagation of construction equipment noise in piling work by SIP(soilcement injected precast pile) method. In addition, this study intends to get the basic data to establish a standard about construction noise.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.05a
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• pp.8-9
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• 2021

FCP requires different curvatures and shapes according to the method of division, and it is necessary to manufacture a formwork accordingly. FCP production equipment consists of CNC equipment and side shape control equipment. This can be implemented in various shapes of upper, lower, and side surfaces. In the side shape control equipment, it is implemented as a variable side formwork. Among the required performance of the variable side formwork, there is stiffness against side pressure, which needs to be verified. Therefore, in this study, the FCP fabrication experiment is conducted with the developed variable side formwork. By analyzing the error in the shape of the fabricated FCP, the lateral pressure resistance capability of the side form is measured and verified.

• International journal of advanced smart convergence
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• v.11 no.4
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• pp.216-226
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• 2022

In this study, we selected and trained 9 people in the diaphragm training group and 9 people in the power-breath training group among elderly people aged 65 or older living in the community, and investigated the effect of combined training using respiratory equipment on lung function, balance, and life satisfaction. We conducted the elderly to do combined exercises, twice a week for a total of 6 weeks, that include the breathing training by diaphragm, the breathing training using Power-breath equipment, and the training using a theraband. We evaluated the changes in the lung function, the balance, and the life satisfaction before and after the intervention for our study subjects.As a result of our measurement, lung function, balance, and life satisfaction showed significant changes in the experimental group that performed the combined training using Power-breath equipment. As a result of the study, we confirmed that the elderly in the community had a positive effect on the life satisfaction by improving lung function and balance ability after conducting a combined training using respiratory equipment.

• International conference on construction engineering and project management
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• 2013.01a
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• pp.188-195
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• 2013

Construction operations generate a significant amount of air pollutant emissions, including carbon emissions. The environmental performance of construction operations is closely relevant to the operational efficiency of each resource employed, which indicates how efficiently each resource (e.g., construction equipment) is utilized. In this context, monitoring the operational efficiency of construction equipment provides key information in managing and improving the environmental performance and productivity of construction operations. In this paper, we report our efforts to measure the operational efficiency of construction equipment, using low-cost accelerometers. An experimental study and real-world case studies are conducted to demonstrate the feasibility of the proposed approach. The results have shown the potential of this approach as an economically feasible means of monitoring the environmental performance of construction operations.

• Journal of the Korean earth science society
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• v.27 no.2
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• pp.177-187
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• 2006

Due to a lack of reproducibility and visibility of the conventional equipment for westerly wave simulation, it is difficult to have indoor experiments at high school that show the stream of Hadley cell. A modified improvement of the old one improves the problem. The side wall and bottom of the new equipment is made by copper and acrylic resin, respectively, in order to clarify the difference between the water temperature inside and outside of the water tank. The equipment also has a high quality digital record for generating exact analysis of the results. And we also carried out several experiments that relate theoretical and experimental aspection of westerly wave. Temperature Detected Sheet (TDS) in flow visualization unit provides not only visual information of liquid flow, but also clear understanding of the relation between upper and lower wind flow structure. And the liquid stream simulated in indoor experiment using proposed equipment is commensurate with westerly wave in real atmosphere. The efficiency of educational properties of the proposed equipment is verified indirectly by Likert Scales survey of high school teachers.

• Transactions of the Korean Society of Automotive Engineers
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• v.24 no.1
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• pp.33-38
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• 2016

The turbocharger is an essential component to realize the engine down-sizing. The moment of inertia of turbocharger rotor is an important parameter with respect to acceleration performance of the vehicle. It can be calculated from the CAD software based the geometry data and the material properties. But the accurate value of the inertia of turbocharger rotor must be measured through the experimental method. In this study, the measurement of moment of inertia of turbocharger rotor for 2.0 L spark-ignition engine was carried out. First, an experimental equipment using a trifilar method was designed and fabricated. Some optical devices, that is, photo sensor, counter, convex lens, etc, were used to increase the accuracy of the measurement. Second, error sensitivity for the equipment was analyzed. The error of period time and the radius can give big affects to the accuracy of the moment of inertia. When the amount of error of these two were each 1.0 %, maximum error of the moment of inertia was under 3.0 %. Third, the calibration for the equipment was performed using a calibration rotor which has similar shape to turbine rotor but simple. Calculated value from CAD software and measured one for the calibration rotor were compared. The total error of the equipment and the measurement is about 1.3 %. This result shows that the equipment can give the good result with resonable accuracy. Finally the moment of inertia of the turbine rotor and compressor wheel were measured. The coefficient of variations, the ratio of standard deviation to mean value, were reasonably small at 0.57 % and 0.73 % respectively. Therefore this equipment is suitable for the measurement of the moment of inertia of the turbine rotor and compressor wheel.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.3173-3177
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• 2007

Recently, we have many problems on the process of the sludge. In past, the sewage sludge was treated by reclaimed land or thrown away in the sea. But these methods caused environmental pollution. Today, many researchers are studying various methods for reducing its volume. One of these method, this study is to reduce the moisture of sewage sludge and to solidify it using a dryer and curing equipment. In this research, we investigated about design parameter and operation condition of the equipment. The curing equipment reduces the percentage of water content from 30% of dryer to 10%. So, we have to study the curing characteristics and performance of curing equipment. For example, there are internal flow characteristics and change of the percentage of water content. And we investigated the change of data at outlet along the initial condition, temperature, humidity and air flow. Using this data, we achieve the experimental results of curing efficiency by each geometry and operating condition. And we also investigated numerical analysis of internal flow using CFD code. This research is basic study for optimal design of the curing equipment.