• Journal of the Korean Society for Aeronautical & Space Sciences
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• 제37권11호
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• pp.1157-1163
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• 2009

This paper introduces the lithium ion battery management system for STSAT-3 satellite. The specifications of lithium ion battery unit are proposed to supply power to the satellite and the overall electrical design for lithium ion battery BMS is presented. Furthermore, the test results of battery management system are shown to verify the design.

• Research in Community and Public Health Nursing
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• 제30권3호
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• pp.271-280
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• 2019

Purpose: This study evaluates the efficacy of a Self-Care Reinforcement Program (SCRP) based on the Selection Optimization Compensation (SOC) model, in socially vulnerable elderly women with metabolic syndrome. Methods: This study adopts a pretest-posttest nonequivalent control group design. The participants were 64 socially vulnerable elderly Korean women with metabolic syndrome (experimental group: 31, control group: 33). Participants' body composition analysis, nutrient intake, risk factors of metabolic syndrome, depressive symptoms, and social network were measured. Data were analyzed with an independent t-test; statistical significance levels were set at p<.05. The SCRP, including metabolic syndrome education, nutritional education, exercise, and social network, was performed three times a week for 8 weeks. Results: There were statistically significant differences between the experimental and control groups in terms of systolic blood pressure, diastolic pressure, fasting blood sugar, triglycerides, sodium intake, depressive symptoms, and social networks. Conclusion: The SCRP is effective and can be recommended as a community health nursing intervention for socially vulnerable elderly women with metabolic syndrome.

• Journal of Sensor Science and Technology
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• 제30권6호
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• pp.420-428
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• 2021

In this study, linearized sweeping of a wavelength sweeping laser was realized. This technique was used to measure the strain on a fiber Bragg grating(FBG) sensor. For linear sweeping, PID control over the wavelength difference between linear and nonlinear sweeping was employed. The performance test showed that linear sweeping with a 46 nm range and a 1 kHz frequency held up well with a 99.5 % decrement in nonlinearity after the 120th feedback. When attached to a strain gage, the FBG sensor registered strain that matched the data sheet within a difference of 4.5[με]. Altogether, linear sweeping can play a leading role in monitoring a safety of large SOC structures as well as in other wavelength sweeping laser related fields.

• KEPCO Journal on Electric Power and Energy
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• 제8권2호
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• pp.143-149
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• 2022

As ESS safety issues increase recently, there is a need to more precisely monitor the temperature of the ESS. In this paper, DTS technology for temperature monitoring of ESS batteries is introduced and the temperature measurement principle is explained. The temperature of the battery module is measured using the DTS system, and the thermal deviation between battery cells inside the battery module is analyzed. In order to analyze how thermal imbalance affects the charging and discharging performance of the battery, an accelerated degradation test was conducted. Cycle life characteristics analysis, battery surface temperature change, and AC impedance characteristics were conducted to analyze how the performance of battery cells differs according to temperature conditions.

• Proceedings of the Korean Geotechical Society Conference
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• 한국지반공학회 2008년도 춘계 학술발표회 초청강연 및 논문집
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• pp.587-598
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• 2008

In the trackbed design using elastic multi-layer model, the stress-dependent resilient modulus is an important input parameter, which reflects substructure performance under repeated traffic loading. The resilient moduli of crushed stone and weathered granite soil were developed using nonlinear dynamic stiffness, which can be measured by in-situ and laboratory seismic tests. The prediction models of resilient modulus varying with the deviatoric or bulk stress were proposed (Park et al., 2008). To investigate the performance of the prediction models proposed herein, the elastic response of the test trackbed near PyeongTaek, Korea was evaluated using a 3-D nonlinear elastic computer program (GEOTRACK) and compared with measured elastic vertical displacement during the passages of freight and passenger trains. The material types of the test sub-ballasts are crushed stone and weathered granite soil, respectively. The calculated vertical displacements within the sub-ballasts are within the order of 1mm, and agree well with measured values with the reasonable margin. The prediction models are thus concluded to work properly in the preliminary investigation. The prediction models proposed for resilient modulus were verified by the comparison of the calculated vertical displacements with measured ones during train passages.

• Proceedings of the Korean Geotechical Society Conference
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• 한국지반공학회 2010년도 춘계 학술발표회
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• pp.221-228
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• 2010

A sliding accident on the road have a high percentage by road freezing, especially, it is often appeared at bridges and Tunnel of freezing areas. Thus, the stability of road operations is enhanced by preventing a partial freezing phenomenon. According to the geothermal snow melting system analysis, a pattern of thermal conductivity is found out about pavement materials of concrete and asphalt when it is buried. The thermal conductivity study is essential that be applied the geothermal snow melting system according to heating exchanger pipe laying of lower pavements. The model tests are conducted on low temperature in freezer using the manufactured test model which is equal to pavement materials. And Many variables are discovered from numerical analyzes of the same conditions with model test.

• Journal of Hydrogen and New Energy
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• 제21권3호
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• pp.207-213
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• 2010

Fuel consumption measurement of hydrogen fuel cell vehicle is considerably different from internal combustion engine vehicle such as carbon balance method. A practical method of fuel consumption measurement has been developed for hydrogen fuel cell vehicles. There are three method of hydrogen fuel consumption testing, gravimetric, PVT (pressure, volume and temperature), and mass flow, all of which necessitate physical measurements of the fuel supply. The purpose of this research is to measure the fuel consumption of hydrogen fuel cell vehicles on chassis-dynamometer and to give information when the research is intended to develop test method to measure hydrogen fuel economy.

• Journal of Astronomy and Space Sciences
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• 제25권4호
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• pp.471-480
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• 2008

COMS Image Data Acquisition and Control System (IDACS) plays a key role in real time ground processing of Meteorological and Ocean observation data. Beyond processing, it serves processed image data and additional data to end users through the spacecraft in the internationally recommended format. The IDACS will be installed at three location (MSC, KOSC, and SOC) and automatically operated 24h/365days. After the IDACS subsystem tests and inter -subsystem interface tests had been completed in the first half of 2008, the acceptance test which was a comprehensive test performed as an integrated form to verify function performance and operational requirements. This paper introduces test objective, preparation, and major result of the COMS IDACS acceptance test.

• International Journal of Highway Engineering
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• 제17권6호
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• pp.47-54
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• 2015

PURPOSES : The objective of this study is to evaluate the early adhesive characteristic of asphalt emulsions, including polymer-modified emulsions, for chip seals using the surface energy concept, the bitumen bond strength (BBS) test, and the Vialit test. METHODS : Two general methods, the BBS test and Vialit test, were applied to investigate the bond strength and the aggregate loss, respectively. A new theory, the surface free energy (SFE) theory, was used to evaluate the adhesive characteristic between the emulsion and the aggregate. Based on the theory, the contact angles were measured, and then the surface energy components were calculated. Using those components, the work of adhesion (Wa) was calculated for each emulsion. To ensure reliable results, all the tests were performed under the same conditions, i.e., at $25^{\circ}C$ for 240 minutes of curing time. For the materials, three emulsions (CRS-2, CRS-2L, and CRS-2P) and one aggregate type (granite) were employed. RESULTS AND CONCLUSIONS : Under the same conditions, the modified emulsions showed better adhesive characteristics and curing behaviors than the unmodified emulsions. In addition, there was no significant difference between the various modified emulsions. One of the important findings is that the analysis by Wa presents more sensitive results than other methods. The results of the Wa showed that the CRS-2P emulsion has the best adhesive characteristics. Consequently, the use of modified emulsions for chip seals could prevent aggregate loss and allow open traffic earlier.

• Journal of the Korean Geotechnical Society
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• 제21권9호
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• pp.35-44
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• 2005

Recently, underground cavities such as limestone cavity and abandoned mine give rise to a lot of damage in SOC facilities. But there are many difficult problems such as delay of the working terms and enormous economic losses in finding a new method and changing construction design. In this study, a new filling material for underground cavities was developed using the stone-dust classified as industry waste polluting environment. As a result of test, filling material properties was that a compressive strength was $34{\~}60\;kgf/cm^2$, a change ratio in length was $0.268{\~}0.776\%$ and water absorption was $34.3{\~}46.9\%$. Also as a result of suspended mass test and pH test, it was confirmed that the developed filling material has a characteristic of non-separating in water and it was an environmentally friendly material.