• Journal of Institute of Control, Robotics and Systems
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• v.13 no.10
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• pp.1025-1031
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• 2007

GPS is widely used for positioning applications and attitude of a vehicle can be found also with multiple antennas. However, extremely weak signal level prevents GPS from indoor operation. DR with accelerometers and gyros and landmark based localization method used for indoor applications increase complexity and cost. In this paper, a simple but very efficient ultrasound based attitude determination system which determines both position and attitude in WSN is given. The range between transmitter and receivers are measured using the arrival time difference between ultrasound and RF signal. The 3 dimensional positions can be found using more than 3 range measurements. Furthermore, if more than 2 transmitters are used, the attitude can be determined using the baseline vectors obtained by differencing transmitter and receiver positions. The prototype system is implemented to evaluate the performance of the proposed method. In addition, an error analysis shows the relation between the attitude error and basel me length, quality of measurement and orientation of a vehicle. The static and dynamic experiments performed by micro mobile robot shows accurate position with less than 1.5cm error and attitude with less than 1 degree error can be obtained continuously with 20cm baseline. It is expected that these results can be adapted without modification to indoor applications such as home cleaning robot and autonomous wheelchair maneuvering.

• Corrosion Science and Technology
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• v.3 no.2
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• pp.59-66
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• 2004

In construction of new ships and large steel bridges in Korea, pre-construction primers (PCP), also known as shop primer, are routinely used and retained as an integral part of the protective coating system. Retention of PCP's can significantly reduce building schedule and cost. Retaining PCP through the so-called "sweep blasting" procedure eliminates or minimizes the necessity of a second blast operation, thus shortening overall schedule as well as reducing labor cost and hazardous waste disposal cost. This study evaluates the feasibility of retaining PCP as the part of primer for high performance protective coating systems applied to ships' hull, bottom and ballast tanks. Upon proving that the retention of the PCP is a viable option, the process of coating application can he improved significantly in terms of cost and working schedule of new ships and large steel bridges. Results indicate that use of the PCP via sweeping blasting in conjunction with standard high performance protective coating systems does not degrade the overall performance of the coating systems. At the same time, it is also highly recommended that the secondary surface preparation should consist of grit blasting of weld burnt and other damaged areas to SSPC SP-IO grade (Sa 2.5 Gr.), Near White Blast Cleaning with proper application and attention to detail.

• The Research Journal of the Costume Culture
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• v.19 no.2
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• pp.346-359
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• 2011

The purpose of this study was to examine students' reasons and standards for purchasing their casual upper garments through online shoppin. A questionnaire composed of 26 items in five-point Likert type (14 items for measuring reasons, and 12 items for measuring standards for their purchase) was administered. The subjects were 422 male and female students attending middle schools, high schools and colleges located in the metropolitan region of Daegu. For a statistical analysis, a $3{\times}2$ two way ANOVA design (3 levels of schools: middle school, high school and college and 2 sexes: male and female) was involved, and Turkey's HFD multiple comparisons were made. The results showed that the reasons for students' purchasing casual upper garments through online shopping malls were as follows: quality, availability of discount coupons and points, other benefits such as special promotions, gifts, the easy return of goods and refunds, and also no trial of wearing shirts even at off-line stores. Significant differences in purchasing reasons through online shopping were found among middle schoo, high school and college students. There were also significant differences between male and female students mostly found in three variations of purchasing reasons: ease of availability of garments in contemporary fashion, convenient shopping without any restriction on time, and the decision to purchase with help from consumers' recommendations. Significant differences among middle school, high school and college students were found in the following standards for the students' decision to purchase their casual upper garments through online shopping: affordability, color, design, style, payment safety, and ease of maintenance (cleaning and ironing). Differences between male and female students were found to be significant in the following categories: affordability, fashionable, brand name, free delivery, product quality, coordination with other clothes, and consumers' recommendations on the products concerned.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.33 no.1
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• pp.56-59
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• 2020

Porcelain insulators are typically exposed to surface discharge and lightning impulse in service. This study investigates the insulation characteristics of the external and internal discharges of a porcelain insulator with respect to its flashover for a 154 kV transmission line. The experiments are also conducted using a wet flashover test and an impulse test based on the external discharge and the internal penetration, to classify the flashover voltage-time curve of the porcelain insulator. When an impulse with a strength of 2,500 kV/㎲ was applied three times to 6.5 mm ceramic samples, electrical penetration of approximately 70% occurred. The impulse experiment confirmed that the electrical penetration inside the porcelain insulator coincided with the area where the electric field was concentrated. The wet flashover voltage test revealed that the flashover threshold voltage increases by approximately 7% after cleaning of the surface.

• Journal of Microbiology and Biotechnology
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• v.27 no.4
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• pp.747-758
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• 2017

Chronic wounds, pressure sores, lesions, and infections of microbial origin in bedridden, paralyzed, or malnutrition patients remain the object of study of many researchers. A variety of factors behind the development of these disorders are related to the patient's immune system, making it unable to respond effectively to the treatment of the wound. These factors can be properly controlled, giving particular importance to the ethiology and stage of the wound, as well as the time periods corresponding to the replacement of the dressings. The present research reports a novel foam/soft material, ${{\small}L}$-Cys-g-PCL, with an application for decubitus/pressure ulcers, especially for wounds with a difficult healing process due to infections and constant oxidation of the soft tissues. During this work, the interactions between S. aureus and ${{\small}L}$-Cys-g-PCL foam were studied under conditions that simulate decubitus ulcers; namely, pH and exudate. The effects of duration of grafting (1 or 8 h) and pH (7.0 and 8.9) on wettability, surface energy, swelling, and porosity were also evaluated. Results showed an effective microbicidal activity exhibiting an inhibition ratio of 99.73% against S. aureus. This new ${{\small}L}$-Cys-g-PCL soft material showed saftey to contact skin, ability to be shaped to fill in sunken holes (craters) - pressure ulcers stage III - and to act as a smart material responsive to pH, which can be tailored to develop better swelling properties at alkaline pH where exudates are normally higher, so as to address exudate self-cleaning and prevention of desiccation.

• Journal of Korean Society for Atmospheric Environment
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• v.19 no.4
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• pp.387-396
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• 2003

A field study was conducted during the summer time of 2002 to determine compositions of volatile organic compounds (VOCs) emitted from vehicles and to develop source emission profiles that is applied to CMB model to estimate the source contribution of certain area. Source emission profile is widely used for the estimation of source contribution by the chemical mass balance model and have to be developed applicable for the target area of estimation. This study was aimed to develop source emission profile and estimation of source contribution of VOCs after application of the chemical mass balance (CMB) receptor model. After considering the emission inventory and other research results for the VOCs in Seoul, Korea, the sources like vehicle emission (tunnel), gas station (gasoline, diesel), solvent usage (painting operation, dry cleaning, graphic art), and gas fuels were selected for the major VOCs sources. Furthermore, ambient air samples were simultaneously collected from 09:00 to 11:00 for four days at eight different official air quality monitoring sites as receptors in Seoul during summer of 2001. Source samples were collected by canisters, and then about seventy volatile organic compounds were analyzed by gas chromatography with flame ionization detector (GC/FID). Based on both the developed source profiles and the database of the receptors, CMB model was intensively applied to estimate mass contribution of VOCs sources. Examining the source profile from the vehicle, the portion of alkanes of VOCs was highest, and then the portion of aromatics such toluene, m/p-xylene were followed. In case of gas fuel. they have their own components; the content of butane, propane, ethane was higher than any other component according to the fuel usage. The average of the source apportionment on VOCs for 8 sites showed that the major sources were vehicle emission and gas fuels. The vehicle emission source was revealed as having the highest contribution with an average of 49.6%, and followed by solvent with 21.3%, gas fuel with 16.1%, gasoline with 13.1%.

• Food Science of Animal Resources
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• v.30 no.1
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• pp.73-86
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• 2010

The current study was designed to optimize solid phase microextraction (SPME)-GC-MS conditions for extraction and analysis of volatile components for Hanwoo beef and to establish a tentative database of flavor components. Samples were taken from Hanwoo longissimus muscle (30 mon old steer, $1^+B$ carcass grade) at 24 h postmortem. Results indicated that the optimum adsorption time for $75{\mu}m$ CAR/PDMS fiber was 60 min at $60^{\circ}C$. Thermal cleaning at $250^{\circ}C$ for 60 min was the best practice for decontamination of the fiber. A short analysis program with a sharp oven temperature ramp resulted in a better resolution and higher number of measurable volatile components. With these conditions, 96 volatile compounds were identified with little variation including 22 aldehydes, 8 ketones, 31 hydrocarbons, 12 alcohols, 8 nitrogen- and sulfurcontaining compounds, 5 pyrazines and 10 furans. A noticeable observation was the high number of hydrocarbons, aldehydes, ketones, alcohols and 2-alkylfurans which were generated from lipid decomposition especially the oxidation and degradation of unsaturated and saturate fatty acids. This implies that these compounds can be candidates for flavor specification of highly marbled beef such as Hanwoo flavor.

• Journal of the Korean Home Economics Association
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• v.42 no.6
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• pp.43-53
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• 2004

The purpose of this paper is to investigate the dyeability, antibacterial activity, and deodorization of cotton and silk fabrics dyed with extracted solution from Chrysanthemum boreale. The results are as follows： 1. The optimum conditions of dyeing temperature and time for the cotton fabrics were 90$^{\circ}C$ and 60minutes, while those of the silk fabrics were 60$^{\circ}C$ and 30 minutes respectively. 2. The K/S values of cotton fabrics were slightly higher than those of silk fabrics. The K/S values of both fabrics were slightly increased by mordanting with Cr but were decreased by mordanting with Cu and Fe 3. The colors of the cotton and silk fabrics changed from GY to Y. In both cases, the values of the fabric colors were lowered, and the values of the colors continued to be lowered with Cu and Fe. The chroma and color difference of both fabrics were high and were further increased by mordanting with Cu. 4. The fastness to dry-cleaning and rubbing of the cotton and silk fabrics was very good. The fastness to washing of both fabrics was good except when mordanted with Fe. The fastness to perspiration of both fabrics was fairly good, but the fastness to acid perspiration was poorer than that to the alkaline perspiration. The fastness to light of both fabrics was very poor. 5. The cotton and silk fabrics showed excellent antibacterial activity. Both fabrics mordanted with Cu showed perfect antibacterial activity. 6. The deodorization of the silk fabrics was very good, and that of the silk fabrics mordanted with Cu and Al was excellent, while the deodorization of the cotton fabrics was fairly good.

• Particle and aerosol research
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• v.7 no.3
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• pp.87-97
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• 2011

In this study, we organized the test results obtained from the performance tests for the CA certificated air cleaners which had been commercially available in Korea since 2003, and analyzed the correlation among the test parameters such as flow rate, particle collection efficiency, clean air delivery rate (CADR), ozone emission, odor removal efficiency and noise level etc. The noise level of 267 air cleaners were increased as concentrated at the 45, 50, 55 dB, which are the required noise level for CA certification according to flow rate, and ozone emissions from the CA air cleaners were significantly lower than the requirement limit, 50 ppb for 24 hour operation. The average particle collection efficiency and odor removal efficiency were 89.3 and 80.8%, approximately 20% higher than the requirement of CA certification, regardless of flow rates. The particle removal performance of an air cleaner was clearly discriminated by its CADR, and the CADR was obtained with a simple calculation: 0.79 x flow rate. The low differentiation of gas removal performance of air cleaners by the current CA gas test method was improved by 3.2, 751.3, 13.4 times for ammonia, acetic acid, respectively, by adopting the CADR concept and the real time measurement method, FTIR, for gas removal performance test.

• Korean Journal of Occupational Health Nursing
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• v.19 no.2
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• pp.190-204
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• 2010

Purpose: This study was conducted to obtain the fundamental data on prevention and management of musculoskeletal symptoms, and to assess the prevalence, risk factors and job characteristics of musculoskeletal symptoms in hotel employees. Methods: The work sampling analysis was carried out by OWAS, and the prevalence was surveyed in term of NIOSH diagnostic criteria and work related risk factors on 263 hotel employees in Busan, Korea, using structured self-administered questionnaire from Jan. 20 to Feb. 26, 2010. The collected data were analysed by the SPSS 18.0. Results: 1) The prevailing rate of musculoskeletal symptoms by NIOSH diagnostic criteria was 43.80% for total subjects and 27.91% for shoulders, 12.79% for neck, and 11.24% for back/waist, respectively. 2) Factors affecting the prevalence of musculoskeletal symptoms were examined and multivariate logistic regression analysis was performed. As a result, women, having a burden of musculoskeletal work, increased work time in case of a higher risk of the prevalence of musculoskeletal symptoms (P<0.1). 3) The body parts and the department with the prevalence of musculoskeletal symptoms showed a significant difference (P<0.05) compared with symptoms on shoulders, arms/elbows, and ankles/feet. Conclusion: The prevalence of musculoskeletal symptoms by NIOSH diagnostic criteria in hotel employees was relatively high showing 43.80% for total subjects and higher in departments of laundry, reservations, cooking, food&beverage, dishwashing, and room cleaning than others.