• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2070-2075
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• 2008

Identification of steady-state is the first step in developing a fault detection and diagnosis (FDD) system. In a complete FDD system, the steady-state detector will be included as a module in a self-learning algorithm which enables the working system's reference model to "tune" itself to its particular installation. In this study, a steady-state detector of a residential air conditioner based on moving windows was designed. Seven representing measurements were selected as key features for steady-state detection. The optimized moving window size and the feature thresholds was suggested through startup transient test and no-fault steady-state test. Performance of the steady-state detector was verified during indoor load change test. From the research, the general methodology to design a moving window steady-state detector was provided for vapor compression applications.

• Proceedings of the Korea Water Resources Association Conference
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• 2010.05a
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• pp.77-81
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• 2010

This study carried out hydraulic model test for water circulation system in Cheongna district as part of Incheon Free Economic Zone. Canal way project of Cheongna was planned to establish for environment-friendly water circulation system, improve quality of life and diversification of traffic through using boat as a water-friendly international business city. The navigation canal, There are two intake facility in central park and it can purify water 15,000$m^3$ per day. After purify, water move to 8 facility of water culture area which supplies water in canal way. This process called water circulation system in cheongna. Also, there are several flow induction machine in canal way except south-north way. Therefore, this study will verify about validity of water circulation system's safety through hydraulic model test.

• Journal of the Korean Society of Industry Convergence
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• v.22 no.6
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• pp.615-626
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• 2019

In this study, the applicability of PHC pile jointing method using rectangular steel tubular was studied. PHC pile joints are welded and bolt assembly. The bolt assembly method is a method that improves the various problems of welded joints. Numerical analysis and tests were conducted to analyze the applicability of the PHC pile jointing method using a rectangular steel tubular. The tests were carried out to test the material properties of the rectangular steel tubular material and the bending test of the pile joints. The numerical analysis was interpreted in the same conditons as the tests conditions. As a result, the material strength of each rectangular steel tubular could be used as a joint material. In the bending test, it was evaluated as a sTable material above the allowable stress of piles. In the numerical analysis results under the same conditions as the tests, it was possible to apply the pile joint material without exceeding the allowable stress of the material.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.03a
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• pp.442-447
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• 2008

A numerical analysis has been conducted to investigate and characterize the unsteadiness of flow structure and oscillatory vacuum pressure inside of a supersonic diffuser equipped to simulate the high-altitude rocket test on the ground. A physical model of concern includes a rocket motor, a vacuum chamber, and a diffuser, which have axisymmetric configurations, using nitrogen gas as a driving fluid. Emphasis is placed on investigating physical phenomena of very complex and oscillatory flow evolutions in the diffuser operating at very close to the starting condition, i.e. minimum starting condition, which is one of major important parameters in diffuser design points of view.

• Annals of Pediatric Endocrinology and Metabolism
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• v.23 no.4
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• pp.215-219
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• 2018

Purpose: We investigated the effect of overweight on luteinizing hormone (LH) levels after a gonadorelin stimulation test in Korean girls with idiopathic central precocious puberty (CPP). Methods: Medical records of 234 girls diagnosed with idiopathic CPP were reviewed retrospectively. CPP was diagnosed when the peak LH levels after gonadorelin stimulation was >5.0 U/L. The enrolled girls had a peak LH level >5.0 U/L after a gonadorelin stimulation test. Selected girls were classified as normoweight (body mass index [BMI] below the 85th percentile with respect to age) and overweight (BMI greater than the 85th percentile with respect to age). Results: The peak LH ($8.95{\pm}2.85U/L$ vs. $11.97{\pm}8.42U/L$, P<0.01) and peak folliclestimulating hormone ($9.60{\pm}2.91U/L$ vs. $11.17{\pm}7.77U/L$, P=0.04) after gonadorelin stimulation were lower in overweight girls with idiopathic CPP than in normoweight girls with idiopathic CPP. Being overweight was negatively associated with peak LH levels after gonadorelin stimulation test (odds ratio, 0.89; 95 % confidence interval, 0.81-0.98, P=0.02). Conclusion: In girls with idiopathic CPP, being overweight led to a lower LH peak after gonadorelin stimulation. Further research is needed to better understand the role of overweight on gonadotropin secretion in precocious puberty.

• The Journal of the Convergence on Culture Technology
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• v.10 no.2
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• pp.439-446
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• 2024

The purpose of this study was to investigate relationship among sexual knowledge, sexual attitudes, and reproductive health promoting behaviors of nursing college students. The research tools utilized were sexual knowledge measurement tool by Jeon(2004), sexual attitudes measurement tool by Ho(2009), and reproductive health promoting behaviors measurement tool by Jo(2014). A total of 300 nursing college students were surveyed, and 229 responses were analyzed. Data analysis was performed using descriptive statistics, t-test, ANOVA, Scheffe's post hoc test and pearson's correlation coefficients with IBM SPSS Statistics 21.0. Female students exhibited higher sexual knowledge, and it was evident that reproductive health promoting behavior education is appropriate during lower academic years. Additionally, the indication that higher sexual knowledge corresponds to higher reproductive health promoting behaviors suggests the ongoing necessity for sexual education to enhance reproductive health promoting behaviors. Therefore, this study could serve as foundational data for developing educational materials on reproductive health promoting behaviors for counseling and education aimed at improving nursing college students' reproductive health.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.12
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• pp.87-98
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• 1999

This study is concentrated on the development of real-time estimation model and vision control method as well as the experimental test. The proposed method permits a kind of adaptability not otherwise available in that the relationship between the camera-space location of manipulable visual cues and the vector of manipulator joint coordinates is estimate in real time. This is done based on a estimation model ta\hat generalizes known manipulator kinematics to accommodate unknown relative camera position and orientation as well as uncertainty of manipulator. This vision control method is roboust and reliable, which overcomes the difficulties of the conventional research such as precise calibration of the vision sensor, exact kinematic modeling of the manipulator, and correct knowledge of position and orientation of CCD camera with respect to the manipulator base. Finally, evidence of the ability of real-time vision control method for manipulator's position control is provided by performing the thin-rod placement in space with 2 cues test model which is completed without a prior knowledge of camera or manipulator positions. This feature opens the door to a range of applications of manipulation, including a mobile manipulator with stationary cameras tracking and providing information for control of the manipulator event.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.605-612
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• 2008

The shear wave velocity ($V_s$) has been commonly used to evaluate the dynamic properties of soil. The field $V_s$ probe (FVP) was already developed to assess the shear stiffness of a soft clay. The objective of this study is to investigate the disturbance effects of the FVP due to the penetration. The laboratory tests are conducted in a large-scale consolidometer (calibration chamber). The reconstituted clay is mixed at the water content of 110% using a slurry mixer. The FVP and down-hole test are carried out every 1cm interval to compare the data. In addition, two square rods with transducers are also implemented to get the reference value. The shear waves evaluated by the FVP, dow-hole tests, and reference rods are closely matched. This study suggests that the disturbance effect of the FVP due to the penetration into the soft clay soils is small enough and the $V_s$ evaluated by the FVP reflects well the in-situ characteristics. Furthermore, the combination of the FVP and down-hole test shows the possibility of hybrid equipment.

• Nuclear Engineering and Technology
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• v.52 no.9
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• pp.1926-1938
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• 2020

We validated the performance of RELAP MOD3.3 code regarding the hybrid SIT with available experimental data. The concept of the hybrid SIT is to connect the pressurizer to SIT to utilize the water inside SIT in the case of SBO or SB-LOCA combined with TLOFW. We investigated how well RELAP5 code predicts the physical phenomena in terms of the equilibrium time, stratification, condensation against Separate Effect Test (SET) data. We also conducted the validation of RELAP5 code against Integrated Effect Test (IET) experimental data produced by the ATLAS facility. We followed conventional approach for code validation of IET data, which are pre-test and post-test calculation. RELAP5 code shows substantial difference with changing number of nodes. The increase of the number of nodes tends to reduce the condensation rate at the interface between liquid and vapor inside the hybrid SIT. The environmental heat loss also contributes to the large discrepancy between the simulation results of RELAP5 and the experimental data.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1405-1405
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• 2011

Sudden earthquake is changing national energy stratagem for future energy resource. In case Germany, current nuke power station will be shut down with several decades. Newly constructed build in Japan must have photovoltaic system as a obligations.. As a long-term sustainable energy one, PV should give confidence to customers up to more than 20 years. Today, IEC 61215 and IEC 61646 standards are representative one for ensuring performance and safety of PV module. But it is still needed to develop more realistic test method. For example, if we think about extreme condition like desert and North Pole, the temperature condition describe in test standards can have little effect on life time expectation of PV module. Installation speed of PV system is very high, but establishing test standards are very complex and not easy. So in this paper, I tried to open the long-term test method for PV module to ensure 25 year's old life time. It is just starting point of PV related long-term test methods. The specific and technical explanation will be shown in the following paper in detail.