• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.11
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• pp.935-943
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• 2020

This paper presents a methodology for evaluating suitability of a manned-unmanned aerial vehicle team for a complicated mission. The study identified vehicle performance, equipment performance and level of autonomy as the key factors that affect the mission effectiveness. A manned and an unmanned aircraft were compared, and their performance was quantized in these respects. SEAD was chosen as a representative manned-unmanned team mission. The SEAD mission was broken down to a sequence of tasks. Mission experts evaluated the importance of each mark item for the mission legs. Combining the results showed proper type of aircraft for each leg depending on the complexity, safety, and importance of the task. Finally, the whole mission plan was laid out as a time-based sequence which alleviate pilot workload significantly.

• Journal of the Korea Institute of Building Construction
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• v.16 no.5
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• pp.389-395
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• 2016

The evolution of electro-mechanical impedance (EMI) of the piezoelectricity (PZT) sensor was investigated to determine the setting times of cementitious materials in this study. The PZT sensor coated with non-conductive acrylic resin was embedded in cement paste before casting and the EMI signatures were continuously measured. Vicat needle test and semi-adiabatic calorimetry test were also conducted to justify the validity of EMI senssing technique in setting monitoring of cementitious materials. The results show that significant changes in EMI resonant peak magnitude and frequency during setting process were observed, and that the setting times determined by EMI sensing technique were relevant to the setting times measured by Vicat needle test and semi-adiabatic calorimetry test.

• Journal of the Korean Society of Clothing and Textiles
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• v.33 no.3
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• pp.410-419
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• 2009

The purpose of this study was to develop the functionally improved winter work clothing for the Korean railroad workers. Based on the questionnaires, sample clothing for the Korean railroad workers was produced. The design, materials, and patterns were modified to increase mobility and comfort for workers. Water-repellent treatment was added to the material in order to decrease the dirt and stains while working. Also, reflective strips were added to side seams and hems of the trousers in order to increase the visibility and safety of the workers. In terms of the design and pattern, a circumference of 4.5cm was added to the crotch area in order to minimize tightness on the hip and crotch areas, but no additional circumference was added to the hip area. And a 1cm width dart was inserted between the side seams and yoke in order to add activity. Also three 1.4cm width tucks were used at 2.5cm space on the knees to alleviate tightness at the knees. The prototype was evaluated objectively and subjectively to compare with the existing working uniform. The assessment group consisted of 5 subject groups and 11 expert groups to evaluate external appearance and adaptability of the movements. Subject and panels were asked to evaluate the prototype that followed an ergonomic design and pattern. According to the results, the prototype was evaluated better than the existing working uniform in appearance and adaptability. A field test was conducted to compare the prototype and the existing working uniform. The field tests were performed by 6 workers in the Korean railroad. According to the results, the prototype advanced in terms of adaptability and comfort.

• 한국지구물리탐사학회:학술대회논문집
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• 1999.08a
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• pp.202-216
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• 1999

The deep foundation is frequently used for the infrastructures. Since the quality control of the cast-in-place concrete foundations such as CIP piles and slurry walls is not so easy as that of the ready made PC(prestressed concrete) piles, it is necessary to get the information on the integrity of the concrete of the foundation. The depth estimation of foundations whose depths are unknown is also very important in repair and reinforcement works or in safety inspection and assessment to the big structures. The cross-hole sonic logging(CSL) system and the single channel reflection seismic measurement system were developed to test the integrity of pile. The former is well applied to CIP structures, while the later to all kinds of piles with less accurate result compared to that of CSL. To estimate the depth of the deep foundations, parallel seismics, borehole RADAR, and borehole magnetics can be used.

• Journal of the Korean Geotechnical Society
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• v.28 no.12
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• pp.65-76
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• 2012

In this study, probabilistic analysis of seepage through a two-layered soil foundation was performed. The hydraulic conductivity of soil shows significant spatial variations in different layers because of stratification; further, it varies on a smaller scale within each individual layer. Therefore, the deterministic seepage analysis method was extended to develop a probabilistic approach that accounts for the uncertainties and spatial variation of the hydraulic conductivity in a layered soil profile. Two-dimensional random fields were generated on the basis of the Karhunen-Lo$\grave{e}$ve expansion in a manner consistent with a specified marginal distribution function and an autocorrelation function for each layer. A Monte Carlo simulation was then used to determine the statistical response based on the random fields. A series of analyses were performed to verify the application potential of the proposed method and to study the effects of uncertainty due to the spatial heterogeneity on the seepage behavior of two-layered soil foundation beneath water retaining structure. The results showed that the probabilistic framework can be used to efficiently consider the various flow patterns caused by the spatial variability of the hydraulic conductivity in seepage assessment for a layered soil foundation.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.1
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• pp.129-135
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• 2013

There is not enough absorption space in the side of a vehicle so injuries to a passenger are higher compared to frontal impact injuries. For the protection of the passenger in the event of a side impact, vehicle regulations and new car assessment program(NCAP) are implemented all over the world. However, passive safety such as absorption technology of vehicle body itself is limited due to the narrow space of the side part. At the present time, it is well known that a side airbag including a curtain airbag is the most effective system to protect the passenger during a side impact. In this study, optimum design of the curtain airbag is carried out to reduce Head Injury Criterion(HIC) of the passenger. Based on crashworthiness simulation, an orthogonal array is selected based on the defined design variables, the response surfaces are generated from the orthogonal array and optimization is conducted with the surfaces.

• Journal of Korea Multimedia Society
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• v.16 no.1
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• pp.87-99
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• 2013

The demands of IC card payment system has been increased according to the rapid advancement of the IT convergence application technologies. Recently IC card payment systems are in demands of the usage space at anytime and anywhere by developing the wireless communication technology and its related multimedia processing technology. Therefore the security of IC card payment system becomes more important and necessary. There are many fault analysis methods to evaluate the security and safety of information systems according to their characteristics and usages. However, the only assessment method to evaluate the security of information systems is not enough to analyse properly on account of the various types and characteristics of information systems by the progress of IT convergence and their applications. Therefore, this paper proposes an integrative method of the Fault Tree Analysis (FTA) and Fault Modes and Effect Analysis/Criticality (FMEA/C) based on criticality to evaluate and improve the security of IC card payment system as an illustration.

• Journal of the Korean Geotechnical Society
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• v.35 no.7
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• pp.5-14
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• 2019

In this study, a prototype abutment was constructed to establish a safety assessment technique of pier and a series of non-destructive tests using impact load. The surcharge load was loaded from 0 tonf to 2.5 tonf on the prototype abutment, and maximum surcharge load was up to 25 tonf. To analyze the behavior of the piers according to the direction of impact, a total of three types of analysis were performed: the direction of the pier, the direction perpendicular to the pier, and the outer direction of the pier. The height of the impact was also tested at each top and bottom. The measuring instrument used an accelerometer to measure the acceleration response when impacted. Based on the series of experimental results, specific values were calculated according to the direction of an impact and the surcharge load using the Fast Fourier Transform (FFT). In addition, the phase difference was used to analyze the pier from the primary 1st mode to the 4th mode.

• Journal of Applied Biological Chemistry
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• v.62 no.3
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• pp.257-264
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• 2019

Rice bran is considered a natural source of antioxidants. In this study, rice bran was fermented with lactic acid bacteria to increase its antioxidant activity. Four strains isolated from fermented food, Lactobacillus plantarum MJM60383, Lactococcus lactis subsp. lactis MJM60392, Lactobacillus fermentum MJM60393, and Lactobacillus paracasei MJM60396, were confirmed as safe through stability tests such as safety assessment for biogenic amine production, hemolytic activity, and mucin degradation, and showed high reducing capacity. The antioxidant activity of rice bran fermentation altered by these strains was evaluated using several methods including measurement of $Fe^{2+}$ chelating activity and scavenging activity by 1,1-diphenyl-2-picryl-hydrazil (DPPH), 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), and nitric oxide assays. In this study, the total phenolic content and ${\gamma}$-oryzanol were evaluated by high-performance liquid chromatography. Compared to non-fermented rice bran and a commercial product, rice bran fermented with Lactococcus lactis subsp. lactis MJM60392 showed the highest phenolic content (844.13 mg GAE/g). Moreover, the content of ferulic acids, ${\rho}$-coumaric acid, and ${\gamma}$-oryzanol in rice bran increased after fermentation with L. lactis subsp. lactis MJM60392 and L. fermentum MJM60393 compared to other samples. Indeed, the DPPH radical scavenging activity and NO scavenging activity were also found to be high in these fermented rice brans. These results indicated that fermentation with lactic acid bacteria increases the active compound levels and the potent antioxidant activities of rice bran.

• Korean Journal of Plant Resources
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• v.34 no.1
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• pp.52-58
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• 2021

Homogenization of quality was important in order to use herbal medicines as pharmaceuticals. To solve this problem, it was important to establish quality standards. Atractylodis Rhizoma Alba has no quantitative method in the Korean Pharmacopoeia. Thus, we have researched to improve the quality evaluation method of Atractylodis Rhizoma Alba with an HPLC. Atractylenolide III and atracylodin were selected as potential marker compounds. This analytical procedure was subject to validation. According to validation guideline of South Korea's Ministry of Food and Drugs Safety, the specificity, linearity, precision, range, quantitative limits, detection limits and accuracy were measured. Because the specificity, linearity, precision, range, quantitative limits, detection limits and accuracy meet criteria of the guideline, the analytic method was validated. With this analysis, Atractylodis Rhizoma Alba and Atractylodis Rhizoma analyzed. As a result, both atractylenolide III and atracylodin appear to be suitable standard compounds. it confirmed that tractylodes Rhizome, similar to Atractylodes Rhizome Alba, could be distinguished.