• Physical Therapy Rehabilitation Science
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• v.13 no.2
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• pp.187-195
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• 2024

Objective: Physical activity can promote physical and mental well-being. University students are more sedentary recently due to the increased use of computers and other technology. The aim of this study was to investigate differences between immersive 360-degree virtual cycling (IVC) and virtual cycling with head-mounted display (VCHMD) on aerobic capacity and usability in young adults. Design: A crossover study. Methods: Twenty-five university students (13 male, 12 female) participated in this study and completed 2 separate 30 min cycling sessions, such as IVC and VCHMD. In the IVC, participants rode on a stationary cycle while watching curved TV where recorded video was played. To enhance the sense of realism, auditory stimulation was given to the headset, and the gyroscope sensor was used to track the screen as the head moved. In the VCHMD, participants rode on the stationary cycle with head-mounted display, and other conditions were the same as IVC. Participants were assessed the aerobic capacity which included gas analyzer and portable near-infrared spectroscopy, and usability which included simulator sickness questionnaire and system usability scale. Results: Aerobic capacity was significantly difference in the IVC compared with the VCHMD except for the total hemoglobin of right and left rectus femoris and muslce oxygen saturation of left rectus femoris (p<0.05). Cybersickness was less in the IVC than VCHMD and usability was high in the IVC than VCHMD (p<0.05). Conclusions: The findings suggested that IVC might be beneficial exericse to improve aerobic capacity and has lower cybersickness and higher usability than VCHMD.

• Restorative Dentistry and Endodontics
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• v.36 no.4
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• pp.290-299
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• 2011

Objectives: The usage of fluoride varnish for a moderate to low caries-risk group has not been well validated. This study aimed to evaluate the preventive and therapeutic efficacies of fluoride varnish on the initiated root caries. Materials and Methods: Ten premolars were sectioned into quarters, further divided into two windows, one of which was painted with Fluor Protector (1,000 ppm fluoride, Ivoclar Vivadent). An initial lesion with a well-preserved surface layer was produced by pH cycling. Scanned line analysis using energy dispersive spectrometry determined the weight percentages of Ca and P in the demineralized layer. Scanning Electron microscopy and confocal laser scanning microscopy (CLSM) evaluated the varnish-applied root surfaces. Results: The mean lesion depth (SD) was 12.3 (2.6) ${\mu}m$ (single cycling) and 19.6 (3.8) ${\mu}m$ (double cycling). Double cycling extended the lesion depth, but induced no more mineral loss than single cycling (p < 0.05). The mean weight percentages of Ca and P between groups with and without varnish were not significantly different (p < 0.05). A CLSM showed varnish remained within 15 ${\mu}m$ of the surface layer. Conclusions: When a mild acid challenge initiated root tissue demineralization, the application of low-concentration fluoride varnish did not influence the lesion depth or the mineral composition of the subsurface lesion.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.7
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• pp.958-963
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• 2009

To improve the quality of boiled rice after storage in rice cookers, temperature was controlled at a lowered condition ($45{\sim}65^{\circ}C$ repeated temperature cycling), compared to the present commercial rice cookers ($75^{\circ}C$). The effect of lowered temperature cycling on the microbial growth, color of rice, and reducing sugar production was measured. The bacteria Bacillus cereus and B. subtilis were killed at $75^{\circ}C$ and $45{\sim}65^{\circ}C$ cycling. The temperature cycling at $45{\sim}65^{\circ}C$ prevented an increase in colony forming unit of E. coli more than the steady temperature at $75^{\circ}C$. Browning during storage was significantly decreased at $45{\sim}65^{\circ}C$ cycling, compared to $75^{\circ}C$. The yellowness increase (${\Delta}b$ value of CIE parameters of the colorimeter) after the 3-day storage was 2.18 at $45{\sim}65^{\circ}C$ cycling whereas 9.12 at $75^{\circ}C$. Reducing sugar was not produced at $75^{\circ}C$ and $45{\sim}65^{\circ}C$ cycling but produced at $30^{\circ}C$ because of the microbial growth. In conclusion, the temperature cycling at $45{\sim}65^{\circ}C$ can improve the quality of stored boiled rice by decreasing the browning and inhibiting the microbial growth.

• Journal of Venture Innovation
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• v.6 no.3
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• pp.95-109
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• 2023

In light of the world grappling with diverse environmental issues due to climate change, the prominence of the 'pre-cycling' movement has grown. This movement strives to curtail or eliminate waste generation even before product purchases, garnering more attention than conventional eco-friendly practices. Consequently, this study employs experiments to delve into effective message strategies for promoting pre-cycling behaviors, which serve as preventive measures against the escalating environmental challenges posed by worsening waste problems. This study investigated the effects of message framing and temporal distance on pre-cycling behavioral intention. In terms of message frame, suggestive messages increased pre-cycling behavioral intention more than coercive messages, and temporal distance had no direct effect on pre-cycling behavioral intention. Assertive messages were associated with higher pre-cycling behavioral intentions when the target was interpreted as near future and suggestive messages were interpreted as distant future. Although temporal distance did not directly affect pre-cycling behavioral intention, it positively influenced consumers' pro-environmental behavioral intention by reducing their antipathy toward assertive messages. The implications of this study extend to the realm of management, offering insights into steering consumer behavior in response to pro-environmental messages.

• Journal of the korean academy of Pediatric Dentistry
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• v.26 no.4
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• pp.677-687
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• 1999

This study was performed to evaluate the effect of aging and thermal cycling on the tensile strength of six commercially available glass-ionomer materials: two chemically set glass-ionomer materials(Fuji II, Fuji IX), two resin-modified glass-ionomer materials(Fuji II LC, Vitremer), and two polyacid-modified composite resins(Compoglass, Dyract). Rectangular tension test specimens were fabricated in a teflon mold giving 5mm in gauge length and 2mm in thickness. All samples were divided into 3 groups. Group 1 was immersed in a $37^{\circ}C$ distilled water for 1 hour. Group 2 was immersed in a $37^{\circ}C$ distilled water for 30 days. Group 3 was subjected to 10,000 thermal cycles between $5^{\circ}C$ and $55^{\circ}C$, and the immersion time in each bath was 15 seconds per cycle. Tensile testing was carried out at a cross-head speed of 0.5mm/min and fracture surfaces were examined with scanning electron microscope. The results obtained were summarized as follows; 1. The polyacid-modified composite resins were stronger than the resin-modified glass-ionomer materials, which were much stronger than the conventional glass-ionomer materials. 2. Tensile strengths were slightly increased after aging treatments for 30days. 3. Tensile strengths of conventional glass ionomers were significantly increased after thermal cycling treatment(p<0.01). 4. The highest tensile strength value of 45.4MPa was observed in the Dyract group and the lowest value of 13.3MPa was observed in the Fuji II LC group after the thermal cycling test, and the strengths of polyacid-modified composite groups were significantly higher than those of other groups. 5. The highest characteristic strength value of 48.6MPa was obtained in the Dyract group, however the highest Weibull modulus value of 8.9MPa was obtained in the Compoglass group after thermal cycling test.

• 한국신재생에너지학회:학술대회논문집
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• 2007.11a
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• pp.192-192
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• 2007

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.1385-1386
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• 2011

• Journal of Korean Society of Environmental Engineers
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• v.37 no.3
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• pp.159-164
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• 2015

This study investigated the environmental risk for up-cycling of air-cooled ladle furnace slag (LFS) and evaluated the mortar compressive strength of binary and ternary blended cements using LFS of 3, 5, 10 wt%. Based on the Soil Environment Conservation Act standard, there was no environmental risk of the up-cycling of LFS. Results of mortar compressive strength assesment showed that the compressive strength of two blended cements using LFS of lower than 5 wt% was about 1.1 times superior to that of un-substituted cement (ordinary portland cement, OPC); however the compressive strength of those with LFS of 10 wt% decreased with 10% compared with that of OPC.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.5
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• pp.640-649
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• 2018

This study analyzed the consumer awareness of cycling wear using web mining, one of the big data analysis methods. For this, the texts of postings and comments related to cycling wear from 2006 to 2017 at Naver cafe, 'people who commute by bicycle' were collected and analyzed using R packages. A total of 15,321 documents were used for data analysis. The keywords of cycling wear were extracted using a Korean morphological analyzer (KoNLP) and converted to TDM (Term Document Matrix) and co-occurrence matrix to calculate the frequency of the keywords. The most frequent keyword in cycling wear was 'tights', including the opinion that they feel embarrassed because they are too tight. When they purchase cycling wear, they appeared to consider 'price', 'size', and 'brand'. Recently 'low price' and 'cost effectiveness' have become more frequent since 2016 than before, which indicates that consumers tend to prefer practical products. Moreover, the findings showed that it is necessary to improve not only the design and wearability, but also the material functionality, such as sweat-absorbance and quick drying, and the function of pad. These showed similar results to previous studies using a questionnaire. Therefore, it is expected to be used as an objective indicator that can be reflected in product development by real-time analysis of the opinions and requirements of consumers using web mining.

• Journal of Environmental Science International
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• v.6 no.6
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• pp.697-709
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• 1997

Sequencing Batch Reactor(SBR) experiments for organics and nutrients removal have been conducted to find an optimum anaerobic/anoxic/aerobic cycling time and evaluate the applicability of oxidation-reduction potential(ORP) as a process control parameter. In this study, a 61 bench-scale plant was used and fed with night-soil wastewater in K city which contained TCODcr : 10, 680 mg/l, TBm : 6, 893 mg/l, $NH_4^+-N$ : 1, 609 mg/l, $PO_4^{3-}-P$ : 602 mg/l on average. The cycling time In SBRs was adjusted at 12 hours and 24 hours, and then certainly included anaerobic, aerobic and inoxic conditions. Also, for each cycling time, we performed 3 series of experiment simultaneously which was set up 10 days, 20 days and 30 days as SRT From the experimental results, the optimum cycling time for biological nutrient removal with nlght-soil wastewater was respctively 3hrs, 5hrs, 3hrs(anaerobic-aerobic-anoxic), Nitrogen removal efficiency was 77.9%, 77.9%, 81.7% for each SRT, respectively. When external carbon source was fed in the anoxic phase, ORP-bending point indicating nitrate break point appeared clearly and nitrogen removal efficiency increased as 96.5%, 97.1%, 98.9%. Phosphate removal efficiency was 59.8%, 64.571, 68.6% for each SRT. Also, we finded the applicability of ORP as a process control parameter in SBRs.