• Journal of Korean Dental Science
• /
• v.4 no.2
• /
• pp.46-51
• /
• 2011

Purpose: For aesthetic reasons, composite resin brackets are widely used. However, related studies are rare. This pilot study sought to compare the stress distributions in two commercially available composite resin brackets with metal slot. Materials and Methods: Two commercially available resin brackets -- full-metal slot resin bracket (fSRB) and partial-metal slot resin bracket (pSRB) with straight wire appliance dimension of $0.022{\times}0.028$ in -- were selected. In each bracket, 3-dimensional finite element models were constructed, and stress level was evaluated using finite element analysis. By loading the tipping force and torsion moment, which are similar to those applied by the stainless steel rectangular wire ($0.019{\times}0.025$ -in), stress distributions were calculated, and von Mises stress values were obtained. Results: In pSRB and fSRB, the stress value of the torque moment was much higher than that of the tipping force. The pSRB showed higher stress value than fSRB in both tipping force and torque moment because of the difference in size and configuration of the metal frame inserted into the slot. More stress was also found to be concentrated on the slot area than the wing area in fSRB. Conclusion: The slot form of fSRB was found to be more resistant to the stress of tipping and torque than the slot form of pSRB. In addition, the slot areas -- rather than the wing areas -- of the bracket showed breakage susceptibility. Therefore, resistance to the torque moment on the slot area should be considered in bracket design.

• Management & Information Systems Review
• /
• v.33 no.4
• /
• pp.99-118
• /
• 2014

Using the theory of attribution, this study investigates the determinants if controllability and explores underlying dimensions of online information credibility, and then investigates if the credibility of online information influences the users' intention to use the online information for evaluating or judging the involved products. Moreover, as a research attempt to investigate the impacts of online information credibility, this study examines whether the main effect of perceived online information credibility on the intention of using online information to make a decision of purchase is mediated by both perceived risk and perceived usefulness. A total of 287 survey forms were collected from online consumers. We examined reliability by exploring internal consistency of the multiple item scales in the overall sample. Convergent and discriminant validity were also examined for evidence of construct validity. Then, PLS technique was employed to test the research model. As a result of analyzing data from a dataset of 287 responses via PLS technique, it is found that (1) both sources (controllability and stability) of perceived credibility are significantly associated with both perceived risk and perceived usefulness, and (2) perceived risk as well as perceived usefulness partially mediate the link between the two sources of credibility and intention to use. The findings of this study also suggest that the two dimensions of online information credibility influence information recipient's intention to use. Moreover, the online information including descriptions about controllability and stability can trigger potential consumers to perceive risk about consumption of the informed products and services. Therefore, providing online information with highly described controllability and stability can increase not only the credibility of the online information itself, but also the intention to use the online information through perceived risk and usefulness.

• Culinary science and hospitality research
• /
• v.21 no.5
• /
• pp.98-108
• /
• 2015

The provincial education office considers providing school lunch as a foodservice and intends to improve consumer satisfaction. This study investigates the effect of student food habits and perceived food quality on satisfaction with school lunch based on Oliver's expectancy disconfirmation theory. We test the moderating effect of student gender and school conditions, such as the location of the school, job positon of the nutrition teacher, renovating kitchen and food distributing place. Questionnaires were collected from 240 sixth graders in the eight elementary schools in Gyeonggi province from August to September 2014. Excluding inadequate questionnaires, 208 were analyzed. PLS (Partial Least Square) and bootstrap t-tests were conducted for this study. The results showed food habits affected satisfaction directly (p<0.01). The perceived food quality of the school lunch service mediated this relationship in part (p<0.01). Moderating effects identified were gender (p<0.1), nutrition teacher's position(p<0.05), and renovating kitchen (p<0.1), but not location of school or distributing place. The study revealed the importance of student food habits and perceived food quality, which had an influence on satisfaction. We make a distinction between the concepts of satisfaction and quality so as to improve student satisfaction. When it comes to offering education program about food habits, the schools with old-fashion kitchen is given priority to than renovating one.

• Fire Science and Engineering
• /
• v.27 no.4
• /
• pp.21-26
• /
• 2013

This study was performed to test the combustive properties of Pinus rigida plates treated with bis-(dimethylaminomethyl) phosphinic acid (DMDAP), bis-(diethylaminomethyl) phosphinic acid (DEDAP), and bis-(dibuthylaminomethyl) phosphinic acid (DBDAP). Pinus rigida specimens were painted in three times with 15 wt% bis-(dialkylaminoalkyl) phosphinic acid solutions at the room temperature. After drying specimen treated with chemicals, combustive properties were examined by the cone calorimeter (ISO 5660-1). It is supposed that the combustion-retardation properties were improved by the partial due to the treated bis-(dialkylaminoalkyl) phosphinic acids in the virgin Pinus rigida. Especially, the specimens treated with chemicals showed both the lower total smoke release rate (TSRR) ($16.94{\sim}18.92m^2/m^2$) and lower $CO_{2mean}$ production (1.98~2.09 kg/kg) than those of virgin plate. However the specimens treated with chemicals showed both the higher peak mass loss rate (PMLR) (0.1250~0.1297 g/s) and higher 1st-smoke production rate (SPR) (0.0153~0.0167 g/s) than those of virgin plate. Compared with virgin Pinus rigida plate, the specimens treated with the bis-dialkylamimoalkyl phosphinic acids showed partially low combustive properties.

• Membrane Journal
• /
• v.21 no.1
• /
• pp.55-61
• /
• 2011

$BaCo_{0.7}Fe_{0.22}Nb_{0.08}O_{3-{\delta}}$ oxide was synthesized by solid state reaction method. Dense ceramic membrane was prepared using as-prepared powder by pressing and sintering at $1,200^{\circ}C$. XRD result of membrane showed single perovskite structure. Leakage and oxygen permeation test were conducted on the membrane sealed by glass ring as a sealing material. The oxygen permeation flux increased with increasing temperature and pressure difference and maximum oxygen permeation flux was $2.3mL/min{\cdot}cm^2$ at $950^{\circ}C$ with $Po_2$ = 0.63 atm of oxygen partial pressure. The oxygen permeation in the condition of air with $CO_2$ (300 ppm) as feed stream decreased as much as only maximum 2.9% in comparison with air feed stream. It indicated $BaCo_{0.7}Fe_{0.22}Nb_{0.08}O_{3-{\delta}}$ membrane is more stable than another membrane for carbon dioxide.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.45 no.11
• /
• pp.1571-1579
• /
• 2016

We investigated the effect of peanut sprout extract (PSE) on andropause symptoms. PSE was evaluated for impotency and benign prostatic hyperplasia via phosphodiesterase (PDE) or 5-alpha reductase II inhibition assay. Inhibition of PDE and 5-alpha reductase II activities in PSE was significantly higher than that of the non-treated control. To investigate the effects of testosterone levels by PSE, we performed cell media test using TM3 cells. Production of testosterone in TM3 cells was elevated by PSE. These results indicate that PSE was able to alleviate andropause symptoms.

• Journal of Broadcast Engineering
• /
• v.9 no.4 s.25
• /
• pp.391-401
• /
• 2004

In this paper, we introduce a novel coding method to efficiently enable spatial random access for high resolution video. In terms of resolution and display size, standard display devices (such as cathode-ray tubes. monitors. PDAs, and LCDs) do not sufficiently support high resolution video such as digital cinema and panoramic video. Currently, users have no choice but to view video at lower resolution as a result of down-sampling, or only a partial region of the video due to display size limitations. Our proposed method. which we call the B-map, represents the set of starting locations of the coded segments in a picture frame. This information, or B-map, is first sent to the decoder prior to the coded data stream of the frame and is then used for fast local decoding. To test our method, we compare our B-map with JPEG tiling and the JPEG Resynchronization marker. Experimental results show that the proposed coding method requires less overhead than existing methods during the same decoding time. The results show promise for future panoramic or digital cinema applications.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.14 no.3
• /
• pp.1451-1458
• /
• 2013

This paper deals with the programs and algorithms that generate the full data set that satisfy the basic combinatorial requirement of combination, permutation, partial permutation or shortly r-permutation, which are used in the application of the total data testing or the simulation input. We search the programs able to meet the rules which is permutations and combinations, r-permutations, select the fastest program by field. With further study, we developed a new program reducing the time required to processing. Our research performs the following pre-study. Firstly, hundreds of algorithms and programs in the internet are collected and corrected to be executable. Secondly, we measure running time for all completed programs and select a few fast ones. Thirdly, the fast programs are analyzed in depth and its pseudo-code programs are provided. We succeeded in developing two programs that run faster. Firstly, the combination program can save the running time by removing recursive function and the r-permutation program become faster by combining the best combination program and the best permutation program. According to our performance test, the former and later program enhance the running speed by 22% to 34% and 62% to 226% respectively compared with the fastest collected program. The programs suggested in this study could apply to a particular cases easily based on Pseudo-code., Predicts the execution time spent on data processing, determine the validity of the processing, and also generates total data with minimum access programming.

• The KIPS Transactions:PartB
• /
• v.9B no.5
• /
• pp.663-672
• /
• 2002

In this paper, Using an automatic tracking system, behavior of an aquatic insect, Chironomus sp. (Chironomidae), was observed in semi-natural conditions in response to sub-lethal treament of a carbamate insecticide, carbofuran. The fourth instar larvae were placed in an observation cage $(6cm\times{7cm}\times{2.5cm)}$ at temperature of $18^\circ{C}$ and the light condition of 10 time (light) : 14 time (dark). The tracking system was devised to detect the instant, partial movement of the insect body. Individual movement was traced after the treatment of carbofuran (0.1ppm) for four days 2days : before treatment, 2 days : after treatment). Along with the other irregular behaviors, "ventilation activity", appearing as a shape of "compressed zig-zag", was more frequently observed after the treatment of the insecticide. The activity of the test individuals was also generally depressed after the chemical treatment. In order to detect behavioral changes of the treated specimens, wavelet analysis was implemented to characterize different movement patterns. The extracted parameters based on Discrete Wavelet Transforms (DWT) were subsequently provided to artificial neural networks to be trained to represent different patterns of the movement tracks before and after treatments of the insecticide. This combined model of wavelets and artificial neural networks was able to point out the occurrence of characteristic movement patterns, and could be an alternative tool for automatically detecting presences of toxic chemicals for water quality monitoring. quality monitoring.

• Journal of Korea Water Resources Association
• /
• v.43 no.8
• /
• pp.733-745
• /
• 2010

Seasonality of hydrologic extreme variable is a significant element from a water resources managemental point of view. It is closely related with various fields such as dam operation, flood control, irrigation water management, and so on. Hydrological frequency analysis conjunction with partial duration series rather than block maxima, offers benefits that include data expansion, analysis of seasonality and occurrence. In this study, nonstationary frequency analysis based on the Bayesian model has been suggested which effectively linked with advantage of POT (peaks over threshold) analysis that contains seasonality information. A selected threshold that the value of upper 98% among the 24 hours duration rainfall was applied to extract POT series at Seoul station, and goodness-fit-test of selected GEV distribution has been examined through graphical representation. Seasonal variation of location and scale parameter ($\mu$ and $\sigma$) of GEV distribution were represented by Fourier series, and the posterior distributions were estimated by Bayesian Markov Chain Monte Carlo simulation. The design rainfall estimated by GEV quantile function and derived posterior distribution for the Fourier coefficients, were illustrated with a wide range of return periods. The nonstationary frequency analysis considering seasonality can reasonably reproduce underlying extreme distribution and simultaneously provide a full annual cycle of the design rainfall as well.