• Journal of the Korean Institute of Telematics and Electronics D
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• v.36D no.1
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• pp.29-37
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• 1999

In this study, we have prepared PLT thin films having various La concentrations by using sol-gel method and studied on the effect of La concentration on the electrical properties of PLT thin films. As the La concentration increases from 5mol% to 28mol%, the dielectric constant at 10kHz increases from 428 to 761, while the loss tangent decreases from 0.063 to 0.024. Also, the leakage current density at 150kV/cm has a tendency to decrease from 6.96${\mu}A/cm^2$ to 0.79${\mu}A/cm^2$. In the result of hysteresis loops of PLT thin films, the remanent polariation and the coercive field decrease from 9.55${\mu}C/cm^2$ to 1.10${\mu}C/cm^2$ and from 46.4kV/cm to 13.7kV/cm, respectively. With the result of the fatigue test on the PLT thin films, we have found that the fatigue properties are improved remarkably as the La concentration increases from 5 mol% to 28mol%. In particular, the PLT28) has paraelectric phase and its charge storage clensity and leakage current density at 5V are 134fC/${\mu}cm^2$ and 1.01${\mu}A/cm^2$, respectively. The remanent polarization and coercive field of the PLT(10) film are 6.96${\mu}C/cm^2$ and 40.2kV/cm, respectively. After applying of $10^9$ square pulses with ${\pm}5V$, the remanent polarilzation of the PLT(10) film decreases about 20% from the initial state. In the results, we conclude that the 10mol% and the 28mol% La doped PLT thin films are very suitable for the capacitor dielectrics of new generation of DRAM and NVFRAM respecitively.

• Progress in Medical Physics
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• v.19 no.1
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• pp.73-79
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• 2008

Retinal prosthesis is regarded as the most feasible method for the blind caused by retinal diseases such as retinitis pigmentosa (RP) or age related macular degeneration (AMD). Recently Korean consortium launched for developing retinal prosthesis. One of the prerequisites for the success of retinal prosthesis is the optimization of the electrical stimuli applied through the prosthesis. Since electrical characteristics of degenerate retina are expected to differ from those of normal retina, we performed voltage stimulation experiment both in normal and degenerate retina to provide a guideline for the optimization of electrical stimulation for the upcoming prosthesis. After isolation of retina, retinal patch was attached with the ganglion cell side facing the surface of microelectrode arrays (MEA). $8{\times}8$ grid layout MEA (electrode diameter: $30{\mu}m$, electrode spacing: $200{\mu}m$, and impedance: $50k{\Omega}$ at 1 kHz) was used to record in-vitro retinal ganglion cell activity. Mono-polar electrical stimulation was applied through one of the 60 MEA channel, and the remaining channels were used for recording. The electrical stimulus was a constant voltage, charge-balanced biphasic, anodic-first square wave pulse without interphase delay, and 50 trains of pulse was applied with a period of 2 sec. Different electrical stimuli were applied. First, pulse amplitude was varied (voltage: $0.5{\sim}3.0V$). Second, pulse duration was varied $(100{\sim}1,200{\mu}s)$. Evoked responses were analyzed by PSTH from averaged data with 50 trials. Charge density was calculated with Ohm's and Coulomb's law. In normal retina, by varying the pulse amplitude from 0.5 to 3V with fixed duration of $500{\mu}s$, the threshold level for reliable ganglion cell response was found at 1.5V. The calculated threshold of charge density was $2.123mC/cm^2$. By varying the pulse duration from 100 to $1,200{\mu}s$ with fixed amplitude of 2V, the threshold level was found at $300{\mu}s$. The calculated threhold of charge density was $1.698mC/cm^2$. Even after the block of ON-pathway with L-(1)-2-amino-4-phosphonobutyric acid (APB), electrical stimulus evoked ganglion cell activities. In this APB-induced degenerate retina, by varying the pulse duration from 100 to $1200{\mu}s$ with fixed voltage of 2 V, the threshold level was found at $300{\mu}s$, which is the same with normal retina. More experiment with APB-induced degenerate retina is needed to make a clear comparison of threshold of charge density between normal and degenerate retina.

• Neonatal Medicine
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• v.17 no.2
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• pp.239-244
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• 2010

Purpose: To evaluate two different heel lancet device in terms of pain response and success of the procedure in the preterm infants undergoing heel puncture. Methods: 100 preterm infants undergoing capillary blood gas analysis or capillary bilirubin monitoring underwent heel puncture, were randomly allocated to blood sampling from the heel with either a conventional manual lancet or an automatic incision device. Primary outcome measures included the Premature Infants Pain Profile (PIPP) score, total duration of procedure, number of heel puncture and number of bruise. The pain response was evaluated using PIPP score and the effectiveness was evaluated using three criteria: total duration of blood sampling, number of puncture, bruising of the heel or ankle. Statistical analysis was performed using the SPSS ver. 13.0 program. Difference between the groups were analysed with t test (continuous variables) and the Chi square test or Fisher test (categorical variables). Results: The mean PIPP score was 4.91 for the automatic lancet group compared with 5.84 for the conventional manual lancet group (P=0.0255).The number of pain scores above 7 during blood collection did not differ between two groups (P=0.2167). The procedure took less time to perform in the automatic lancet group (mean, 30.69 seconds) than in the conventional lancet group (mean, 48.92 seconds) (P<0.0001). Conclusion: This study demonstrated that the automatic lancet device causes less pain and a shorter procedure time than the conventional manual lancet in preterm infants undergoing heel puncture. On the basis of these results the automatic lancet device is very useful method for blood collection in preterm infants by heel puncture.

• Journal of dental hygiene science
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• v.10 no.3
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• pp.131-139
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• 2010

The purpose of this study was to evaluate smoking patterns, oral health behavior and perception of dental healthcare of military personnel in the South Korea Army. All 367 subjects were surveyed by the structured questionnaires with convenience sampling method. The questionnaires were consisting of 22 items. Depending on the conditions of military training, the distribution and differences of smoking patterns and oral behaviors were evaluated by frequency test, Weighted Kappa, Paired t-test and ANOVA. The differences of oral health perception on smoking were demonstrated by Mantel-Haenszel Chi-square test. In addition, Generalized Estimating Equation (GEE) was used to estimate the effects of oral behavior for the conditions of military training and smoking. The number of cigarette during military training period was similar to that during non-military training (p=0.109). The perception of smokers such as smoking effect on oral health, oral health and systemic health, and need of education for smoking cessation was significantly lower than non-smokers (p=0.0095, p=0.0007, and p<0.0001). The probability that toothbrush frequency per day was only one was associated with higher during military training period than non-military training (OR=9.29, 95% CI 5.05-17.07). Moreover, the probability that hours of toothbrush were less than one minute was associated with higher during military training than non-military training (OR=2.19, 95% CI 1.78-2.71). To improve knowledge, attitude, and behavior of oral health for the members, the army needs to develop oral health education and tobacco cessation programs. In particular, motivation and practice for oral health care are required to improve poor oral health behavior during the military training.

• Journal of dental hygiene science
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• v.17 no.4
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• pp.333-340
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• 2017

The prevalence of periodontal disease was steadily increased. The best prevention methods for periodontal disease are teeth brushing and scaling. The purpose of this study was to investigate the status of scaling experience and related factors among some workers. Total 455 workers in 5 manufacturing companies in Gwangju were selected using convenience sampling method. General characteristics, work-related characteristics, oral health-related characteristics and scaling experience were collected by self-reported questionnaires. Chi-square tests, t-tests and multiple logistic regression analysis were performed to investigate the factors influencing the scaling experience using SPSS software. Statistical significance was defined as a p-value<0.05. The proportion of scaling experience during the past year was 47.0%. In simple analysis, age, current working position, number of oral disease, interest in oral health, use of secondary oral products, oral health screening use, oral health education experience and awareness of scaling inclusion in the National Health Insurance (NHI) coverage were associated with scaling experience. Finally, the odds ratios (ORs) for scaling experience were significantly higher in younger subjects (adjusted OR [aOR], 3.09; 95% confidence internal [CI], 1.60~5.96), assistant manager (aOR, 2.68; 95% CI, 1.55~4.63), subjects with high interest in oral health (aOR, 2.15; 95% CI, 1.02~4.52), subjects with oral health screening use (aOR, 2.76; 95% CI, 1.50~5.11) and awareness of scaling inclusion in the NHI coverage (aOR; 2.91, 95% CI, 1.80~4.72) in multiple logistic regression analysis. Scaling experience was relatively low (47.0%). The related factors with scaling experience were age, working position, use of screening and awareness of scaling inclusion in the NHI coverage. Considering these factors will increase the utilization rate of scaling.

• Journal of Animal Environmental Science
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• v.18 no.3
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• pp.247-256
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• 2012

This study was carried out to investigate the effects of various regions of sorghum-sorghum hybrid (SSH) silage on nutritive values and qualities of SSH silage. SSH "SS405" was harvested at ripen stage and ensiled. Samples of SSH silage used in this study were collected in three regions (outside, middle and inside). The contents of crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), total digestible nutrients (TDN) and in vitro dry matter digestibility (IVDMD) in SSH silage were not influenced by SSH silage manufacture methods and lactic acid bacteria. The contents of CP in inside region of SSH silage were lower than those of outside and middle regions (p<0.05). However, the contents of NDF, ADF and TDN, and IVDMD were not different between the regions of SSH silage. The content of lactic acid in SSH round bale silage was significantly decreased (p<0.05), as compared to SSH square bale silage (SB), gunny bag silage (GB) and trench silage (TS). The contents of acetic acid and butyric acid in SSH silage were not influenced by SSH silage manufacture methods and lactic acid bacteria. The contents of lactic acid in inside region of SSH silage were lower than those of outside and middle regions (p<0.05). In addition, the contents of lactic acid, acetic acid and butyric acid were not different between the regions of SSH silage. Therefore we suggest that nutritive values and quality of SSH silage were not influenced by regions of sampling collected from these silages.

• Childhood Kidney Diseases
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• v.11 no.1
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• pp.59-64
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• 2007

Purpose : Suprapubic aspiration(SPA) has been considered the "gold standard" for obtaining urine in non-toilet trained infants. Ultrasound(US)-guided SPA improves the success rate of the procedure and reduces the complications. However, many physicians perceive SPA as invasive and prefer the use of urethral catheterization (Ucat). We compared the success rate, complications and accuracy of US-guided SPA and Ucat. Methods : 121 infants who visited Ewha Womans University Mokdong Hospital with suspected urinary tract infection(UTI) were investigated. For the first study, the study infants were randomly assigned to either the US-guided SPA(n=32) or Ucat(n=32) groups. The success rate and complications of both procedures were compared. For the second study, US-guided SPA and Ucat were performed simultaneously(n=57). The accuracy of urethral catheterization was subsequently analyzed. The criteria for success was defined as the collection of more than 0.5 mL of urine. UTI was diagnosed by the presence of uropathogens over 105 colony-forming units (CFU)/mL. Results : The overall success rate of the US-guided SPA was 96.9%(71.9% in first attempts, 25.0% in second attempts) which was not significantly different compared to 96.9%(90.6% in first attempts, 6.3% in second attempts) in the Ucat(P>0.05) group. The aspirated urine volume was $7.4{\pm}3.7mL$ in the US-guided SPA group, which was not significantly different to $4.5{\pm}2.6mL$ in the Ucat(P>0.05) group. The accuracy of Ucat in comparison to the US guided SPA was low with sensitivity 59.5%, specificity 86.6%, false-positive rate 13.3% and false-negative rate 40.5%. Conclusion : US-guided SPA should be encouraged as the best method to collect the urine in non-toilet trained infants with UTI.

• Journal of the Korean Society of School Health
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• v.12 no.2
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• pp.295-303
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• 1999

The purpose of this study was to evaluate the effect of systemic oral health education on the improvement of knowledge levels and patient hygiene performance(PHP) for elementary school students. The randomly selected 1st and 5th grade students in a public elementary school of Taegu city were divided by education group(118 students) and non-education group(122 students). The oral health education lesson was systematically held on the education group once a month for 4 months. The questionnaire queried all the subjects about their knowledge and attitudes before and after oral health education, and PHP was also tested at the same time. Corresponding p-values were significantly considered at values less than 0.05. The obtained results were as follows: Due to the oral health education lesson, the education group of both 1st and 5th grade students came to have a higher knowledge level than the non-education group. There was high improvement of items such as toothbrushing time, toothbrushing method, cause of dental caries, treatment after tooth damage, and tongue-brushing. Therefore, these items should be educated to all the elementary school students. By increaseing the knowledge level of oral health after education, the PHP index in the education group was significantly decreased in comparison to the non-education group and hence the capability of oral health management improved. From the above results, a systematically and periodically oral health education system for elementary school students can improve the knowledge level and capability of oral health management. Further study will be required to develop an easy and acceptable systemic oral health education program for elementary schools.

• Culinary science and hospitality research
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• v.10 no.3
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• pp.135-154
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• 2004

This study surveyed ancestral service preparation and sacrificial consciousness of housewives living in Pusan and Yeosu area. Statistical analysis of chi-square test was carried out by using SAS program. The results are summarized as follows. l. In major general characteristics of subjects, the forties(35.56%), Buddhism (57.79%), high school education(52.54%), a couple with children(63.45%) were the most abundant. 2. The time of sacrificial rites in both areas was usually hold from 23:00 to 01:00 (47.16%). The housewives having a job hold earlier the service than the full-time housewives(p<0.05). 3. The range of ancestor-memorial rites was usually up to 3rd generation(34.47%). The leader of sacrificial ceremony was mainly the eldest grandson by the eldest son (78.28%) in the old subjects and a person of wealth in the young subjects(p<0.05). 4. There were more positive answers for the necessity of a sacrificial ceremony (57.32%). Older than 50 years of subjects thought the sacrificial rites should be held(70.77%), while as the age of subjects was younger, they realized less necessity for that(p<0.05). Sacrificial consciousness was higher in Buddhists than the other religionists(p<0.0001). The sacrificial rites was thought to be needed for their harmonious family(50.43%). Younger subjects thought that it is necessary to succeed that as the tradition, while older housewives thought that it would contribute toward peace in their family(p<0.05). Buddhists and Christians answered that it was good for harmonious family, and Catholics and the others for tradition(p<0.01). Their consideration of sacrificial rites in the future was higher in keeping the traditional practice (37.04%) and Buddhists took higher these consideration(43.17%). Considering the sacrificial consciousness, there were statistical differences among the religionists (p<0.0001). The eldest daughter-in-raw had a different opinion about the following up the method of sacrificial ceremony from second eldest daughter-in-raw and the next one(p<0.05). The housewives in Pusan were showing more the affirmative attitudes to keep the traditional practice than those in Yeosu.

• Asia pacific journal of information systems
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• v.22 no.4
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• pp.7-29
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• 2012

Smartphone and its applications (i.e. apps) are increasingly penetrating consumer markets. According to a recent report from Korea Communications Commission, nearly 50% of mobile subscribers in South Korea are smartphone users that accounts for over 25 million people. In particular, the importance of smartphone has risen as a geospatially-aware device that provides various location-based services (LBS) equipped with GPS capability. The popular LBS include map and navigation, traffic and transportation updates, shopping and coupon services, and location-sensitive social network services. Overall, the emerging location-based smartphone apps (LBA) offer significant value by providing greater connectivity, personalization, and information and entertainment in a location-specific context. Conversely, the rapid growth of LBA and their benefits have been accompanied by concerns over the collection and dissemination of individual users' personal information through ongoing tracking of their location, identity, preferences, and social behaviors. The majority of LBA users tend to agree and consent to the LBA provider's terms and privacy policy on use of location data to get the immediate services. This tendency further increases the potential risks of unprotected exposure of personal information and serious invasion and breaches of individual privacy. To address the complex issues surrounding LBA particularly from the user's behavioral perspective, this study applied the privacy calculus model (PCM) to explore the factors that influence the adoption of LBA. According to PCM, consumers are engaged in a dynamic adjustment process in which privacy risks are weighted against benefits of information disclosure. Consistent with the principal notion of PCM, we investigated how individual users make a risk-benefit assessment under which personalized service and locatability act as benefit-side factors and information privacy risks act as a risk-side factor accompanying LBA adoption. In addition, we consider the moderating role of trust on the service providers in the prohibiting effects of privacy risks on user intention to adopt LBA. Further we include perceived ease of use and usefulness as additional constructs to examine whether the technology acceptance model (TAM) can be applied in the context of LBA adoption. The research model with ten (10) hypotheses was tested using data gathered from 98 respondents through a quasi-experimental survey method. During the survey, each participant was asked to navigate the website where the experimental simulation of a LBA allows the participant to purchase time-and-location sensitive discounted tickets for nearby stores. Structural equations modeling using partial least square validated the instrument and the proposed model. The results showed that six (6) out of ten (10) hypotheses were supported. On the subject of the core PCM, H2 (locatability ${\rightarrow}$ intention to use LBA) and H3 (privacy risks ${\rightarrow}$ intention to use LBA) were supported, while H1 (personalization ${\rightarrow}$ intention to use LBA) was not supported. Further, we could not any interaction effects (personalization X privacy risks, H4 & locatability X privacy risks, H5) on the intention to use LBA. In terms of privacy risks and trust, as mentioned above we found the significant negative influence from privacy risks on intention to use (H3), but positive influence from trust, which supported H6 (trust ${\rightarrow}$ intention to use LBA). The moderating effect of trust on the negative relationship between privacy risks and intention to use LBA was tested and confirmed by supporting H7 (privacy risks X trust ${\rightarrow}$ intention to use LBA). The two hypotheses regarding to the TAM, including H8 (perceived ease of use ${\rightarrow}$ perceived usefulness) and H9 (perceived ease of use ${\rightarrow}$ intention to use LBA) were supported; however, H10 (perceived effectiveness ${\rightarrow}$ intention to use LBA) was not supported. Results of this study offer the following key findings and implications. First the application of PCM was found to be a good analysis framework in the context of LBA adoption. Many of the hypotheses in the model were confirmed and the high value of $R^2$ (i.,e., 51%) indicated a good fit of the model. In particular, locatability and privacy risks are found to be the appropriate PCM-based antecedent variables. Second, the existence of moderating effect of trust on service provider suggests that the same marginal change in the level of privacy risks may differentially influence the intention to use LBA. That is, while the privacy risks increasingly become important social issues and will negatively influence the intention to use LBA, it is critical for LBA providers to build consumer trust and confidence to successfully mitigate this negative impact. Lastly, we could not find sufficient evidence that the intention to use LBA is influenced by perceived usefulness, which has been very well supported in most previous TAM research. This may suggest that more future research should examine the validity of applying TAM and further extend or modify it in the context of LBA or other similar smartphone apps.