• Journal of Welding and Joining
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• v.30 no.6
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• pp.80-85
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• 2012

Fatigue cracks in structural components are the most common cause of structural failure when exposed to fatigue loading. In this respect, fatigue crack detection and structural health assessment are very important. Currently, various smart materials are used for detecting fatigue crack and measurement of SIFs(Stress Intensity Factors). So, this paper presented a measurement of SIFs using MFC(Micro Fiber Composite) sensor which is the one of the smart material. MFC sensor is more flexible, durable and reliable than other smart materials. The SIFs of Mode I(K I) as well as Mode II(K II) based on the piezoelectric constitutive law and fracture mechanics are calculated. In this study, the SIF values measured by MFC sensors are compared with the theoretical results.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.24 no.6
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• pp.625-631
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• 2015

The hardness of surface treated magnesium alloy was evaluated using laser induced breakdown spectroscopy. The surface of the specimen was hardened mechanically, and the hardness profiles were measured using a traditional measurement technique. A laser beam was irradiated to generate a plasma, and the peaks of the components of the specimen were analyzed. A wavelength of 333.66 nm and 293.65 nm were selected as the atomic and ionic peaks, respectively. The ratios of the ionic peak to the atomic peak were obtained so as to compare the hardness profile. As the depth increased, the ratio decreased. These results are in good agreement with the previous hardness measurement results. It can be considered that this technique could be applied for remote and time-efficient hardness measurement.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1996.11a
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• pp.86-88
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• 1996

A method is presented for the development of the PC-based measurement system on the 6 cathodes-single anode type multi-functional oxygen electrodes for detecting various components of the solution by measuring the dissolved oxygen(DO) concentration. The system is consisted with the 6 channel sensor signal modyfing circuits for the sensor and the PC interface circuits using the single chip microprocessor 80c196kc. Typical polarograms for the DO probes under test using this sensor circuits are presented. This system covers wide range of measuring time from 300sec to over 16 hour in one measurement step by programming the 9 monitor disply mode.

• Korean Journal of Human Ecology
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• v.15 no.6
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• pp.1037-1047
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• 2006

In this paper, various structures of the healthcare smart clothing for real-time measurement of vital sign were suggested. The wearing efficiency was evaluated to find out the best ergonomic clothing in the suggested design. The supplementary effects of the clothing components (princess line, double fabric, cushion) on the stable and tight positioning of sensors to the body were evaluated with wear test. Five experimental clothing for male subject were made with closely-fitted shape and they included two representative structure: one was the integrated type of inner and outer garments and the other was the separated type with two garments. Eight subjects in their twenties were participated in the wear test to evaluate the wearing efficiency of experimental clothing. As results, the clothing structure of the separated garments with the inner and the outer shells were evaluated as more efficient and comfortable. However, the effects of clothing components on the light positioning of the sensors to the body surface were not differentiated each other in the subjective evaluation.

• The Journal of the Acoustical Society of Korea
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• v.24 no.1E
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• pp.7-15
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• 2005

This paper addresses issues encountered in measuring the general, 6-degree-of-freedom motion of a human head, A complete mathematical description for measuring the head motion using the six-accelerometer configured bite-bar is suggested, The description shows that the six-axis vibration cannot be completely obtained without the roll, pitch and yaw angular velocity components, A new method of estimating the three orthogonal (roll, pitch and yaw) angular velocities from the six acceleration measurements is introduced. The estimated angular velocities are shown to enable further quantitative error analysis in measuring the translational and angular accelerations at the head. To make this point clear, experimental results are also illustrated in this paper. They show that when the effects of angular velocities are neglected in the head vibration measurement the maximum percentage errors were observed to be more than $3 \%$ for the angular acceleration of the head and to be close to $5 \%$ for its translational acceleration, respectively. It means that the inclusion of all the angular velocity dependent acceleration components gives more accurate measurement of the head vibration.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.9
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• pp.905-912
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• 2008

Notion sickness is well known to be caused by long time exposure to the very low frequency motion in the multiple axes of human body Since the vestibular system for the perception of low frequency motion is located in the head, accurate measurement of 6 degree of freedom head motion is of great importance. In this study, the measurement system consisting of a safety helmet and 9 translational accelerometers was constructed for the estimation of 3 translational and 3 rotational motions of human head. Since estimation errors of 3 rotational components can be significantly magnified even by small offset of the sensitivity axis from the geometric center of an accelerometer, accurate measurement of sensitivity axis must be preceded. The method for accurate estimation of the offset was proposed, and the effect of offset on the estimation of angular acceleration was investigated.

• Journal of the Korean Solar Energy Society
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• v.24 no.4
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• pp.65-75
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• 2004

This study aims to identify the degree of heat island in summer in Gwangju. For the purpose the city was classified according to use and surface components and temperature of the city for 24 hours was measured. The period of measurement was from August 11 to 13. 2003(two days). As a result of the measurement, the daily standard temperature of the central business areas and downtown areas was about $26^{\circ}C$. That of new residential areas neighboring the downtown was $25.1^{\circ}C$, and that of the outer residential areas was $23.4^{\circ}C$. In comparison with the result that temperatures of the Gwangju University playground and the Gwangju Weather Bureau were $23.1^{\circ}C$ and $23.3^{\circ}C$ respectively, the temperature of the downtown was about $2.7^{\circ}C$ Higher and that of the new residential area in downtown was about $1.8^{\circ}C$ higher. And it was demonstrated that the downtown outer road under Mt. Mudeung is a low-temperature zone. When temperature of the city was measured based on surface components, the daily standard temperature of Gwangju Stream Bok-gae area was the highest, $24.2^{\circ}C$, followed by $23.6^{\circ}C$ of the downtown stream and $22.2^{\circ}C$ of the greens (city park) and the waterside area.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.7
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• pp.4855-4862
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• 2015

This paper proposes low price power component measurement and record system for preventing electrical safety accident and supporting accident cause analysis by periodically monitoring and recording the operation status of electrical equipments. The proposed system was designed by mainly using parts to measure accurate power component but reduce cost. Especially, low cost and high effectiveness system implementation was possible by using MAXIM 78M6631 to calculate power components in the definition of IEEE Standard 1459-2010 related power quality. The measurement performance of the developed system is tested by using standard devices such as YOKOGAWA power analyzer WT1600. The test results showed that accuracy of the developed system is less than 0.5 % and the developed system is tested in a real area to verify the operation reliability and remote monitoring performance of the system over 6 months.

• Journal of the Korean housing association
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• v.21 no.6
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• pp.53-60
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• 2010

Built-in wardrobe is constructing after ordering and making, because built-in wardrobe's size is fixed as housing measurement. It is hard to speak built-in wardrobe components of construction in these ways, and application of an MC (Modular Coordination) design system is meaningless too. And above all, measurement before construction isn't to expect standardization, and to increase custom-made furniture. So I suggest the standardization of built-in wardrobe utilizing standard last finish and reference plane in order to prevent an evil influence of built-in wardrobe's construction. And we utilized a reference plane, and we present construction document and design plan in order to solve these problems. The first stage, we investigate manufacture of a preferential domestic system kitchen and construction state, and we derive from a problem in viewpoints of standardization for this. And we analyze an effect got by application of the assembly basis aspect that we presented, and we can raise efficiency of standardization of housing and construction industry, and we light ultimately up. I will apply a standardization plan as above, and define that this assures a standardization of components and an economic effect.

• Tribology and Lubricants
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• v.32 no.6
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• pp.189-194
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• 2016

Wear debris in lubricating oil can be indicative of potential damage to mechanical parts in rotating and reciprocating machinery. Therefore, on-line or in-line monitoring of lubricating components in machinery is of great importance. This work presents a device based on inductive measurement of lubricating oil to detect magnetic wear particles in a tested volume. The circuit in the device consists of Maxwell Bridge and LVDT to measure inductance differences between pure and contaminated oil. The device detects the passage of ferrous particles by monitoring inductance change in a coil. The sensing principle is initially demonstrated at the microscale using a solenoid. The device is then tested using iron particles ranging from $50{\mu}m$ to $100{\mu}m$, which are often found in severely worn mechanical components. The test results show that the device is capable of detecting and distinguishing ferrous particles in lubricating oil. The design concept demonstrated here can be extended to an in-line monitoring device for real-time monitoring of ferrous debris particles. A simulation using the CST code is performed to better understand the inductive response in the presence of magnetic bodies in the oil. The CST simulation further verifies the effectiveness of inductance measurement for monitoring magnetic particles within a tube.