• Journal of the korean academy of Pediatric Dentistry
• /
• v.28 no.2
• /
• pp.300-309
• /
• 2001

The purpose of this study was to investigate the caries prevalence and caries pattern of preschool children in a small city. Six hundred twenty four kindergarten children in Milyang city were examined for their caries experience of individual teeth and surfaces by dmf index. The obtained results were as follows. 1. The rate of children with caries experience(dmft rate) in primary teeth was 74.0% in 3-year-olds, 83.8% in 4-year-olds, and 90.6% in 5-year-olds. The mean number of decayed, missed, and filled primary teeth(dmft index) was 3.47 in 3-year-olds, 5.41 in 4-year-olds, and 6.01 in 5-year-olds. 2. The caries prevalence of children in this study was higher than those of other researches in past and in other cities. 3. The caries-experienced teeth in order in 5-year-olds were as follows : mandibular 2nd primary molar, mandibular 1st primary molar, maxillary 2nd primary molar, maxillary primary central incisor and maxillary 1st primary molar. 4. The pattern of dental caries development was different between the incisors and molars. The prevalent surface of caries was proximal surface in primary incisors, but occlusal surface in primary molars.

• Journal of Navigation and Port Research
• /
• v.34 no.3
• /
• pp.175-180
• /
• 2010

In the almost application parts, GNSS being used the primary navigation system on world-widely. However, some of nations attempt or deliberate to enhance current Loran system, as a backup to satellite navigation system because of the vulnerability to the disturbance signal. Loran interests in supplemental navigation system by the development and enhancement, which is called eLoran, and that consists of advancement of receiver and transmitter and of differential Loran in order to increase the accuracy of current Loran-C. A significant factor limiting the ranging accuracy of the eLoran signal is the ASF in the TOAs observed by the receiver. The ASF is mostly due to the fact that the ground-wave signal is likely to propagate over paths of varying conductivity and topography. This paper presents comparison results between the predicted ASF and the measured ASF in a southern east region of Korea. For predicting ASF, the Monteath model is used. Actual ASF is measured from the legacy Loran signal transmitted Pohang station in the GRI 9930 chain. The test results showed the repeatability of the measured ASF and the consistent characteristics between the predicted and the measured ASF values.

• Journal of Advanced Navigation Technology
• /
• v.17 no.6
• /
• pp.593-599
• /
• 2013

In this paper, the GPS cycle-slip detection for carrier-phase based positioning of land vehicle is presented. For the carrier phase based positioning, cycle-slip detection is necessary to get the reliability of positioning result. There exists many cycle-slip detection algorithms, but we detect the cycle-slip by using the monitoring value which is defined as residual between the carrier phase measurement and estimated value from low-cost inertial sensor. To achieve goal of paper, low-cost cycle-slip detection system, permissible specification region of inertial sensor is derived. By using the result of permissible region, appropriate inertial sensor of cycle-slip detection can be decided, proper cost and proper specification. To verify the result of this paper, we conduct the rate table test. As a result, required cycle-slip detection performance is satisfied conservatively.

• Journal of Industrial Convergence
• /
• v.20 no.2
• /
• pp.71-78
• /
• 2022

This study intends to present a desirable vision so that students can focus on their studies and adapt to the dental hygiene major education perceived by dental hygiene students in un-contact lecturess situations by preparing measures to increase student satisfaction with the dental hygiene department. Data collection was conducted using a self-reported questionnaire from students in the dental hygiene department at universities in Seoul, Chungcheong, and Gangwon from June 20 to August 19, 2021. Variables according to the general characteristics of the subjects were analyzed using t-test and one-way ANOVA, and the post hoc test was verified by Tukey. The correlation between variables was Pearson's correlation, and the factors affecting dental hygiene and students' major satisfaction were multiple regression. The self-directed learning ability of dental hygiene students was 3.57 points, learning immersion was 3.02 points, and major satisfaction was 3.54 points. Dental hygiene students were found to have higher major satisfaction with higher grades, higher college life satisfaction, and higher learning immersion and self-directed learning ability. Therefore, it was found that systematic program development and application is necessary to improve major satisfaction in difficult circumstances due to COVID-19.

• Journal of Intelligence and Information Systems
• /
• v.29 no.3
• /
• pp.229-247
• /
• 2023

With the increasing emphasis on anomaly detection across various fields, diverse anomaly detection algorithms have been developed for various data types and anomaly patterns. However, the performance of anomaly detection algorithms is generally evaluated on publicly available datasets, and the specific performance of each algorithm on anomalies of particular types remains unexplored. Consequently, selecting an appropriate anomaly detection algorithm for specific analytical contexts poses challenges. Therefore, in this paper, we aim to investigate the types of anomalies and various attributes of data. Subsequently, we intend to propose approaches that can assist in the selection of appropriate anomaly detection algorithms based on this understanding. Specifically, this study compares the performance of anomaly detection algorithms for four types of anomalies: local, global, contextual, and clustered anomalies. Through further analysis, the impact of label availability, data quantity, and dimensionality on algorithm performance is examined. Experimental results demonstrate that the most effective algorithm varies depending on the type of anomaly, and certain algorithms exhibit stable performance even in the absence of anomaly-specific information. Furthermore, in some types of anomalies, the performance of unsupervised anomaly detection algorithms was observed to be lower than that of supervised and semi-supervised learning algorithms. Lastly, we found that the performance of most algorithms is more strongly influenced by the type of anomalies when the data quantity is relatively scarce or abundant. Additionally, in cases of higher dimensionality, it was noted that excellent performance was exhibited in detecting local and global anomalies, while lower performance was observed for clustered anomaly types.

• 치위협보
• /
• s.140
• /
• pp.1-12
• /
• 2009

• Journal of the Institute of Electronics Engineers of Korea SC
• /
• v.40 no.3
• /
• pp.152-162
• /
• 2003

In this paper, Binary to Quaternary Converter(BQC), Quaternary to Binary Converter(QBC) and Quaternary inverter circuit, which is the basic logic gate, have been proposed based on voltage mode. The BQC converts the two bit input binary signals to one digit quaternary output signal. The QBC converts the one digit quaternary input signal to two bit binary output signals. And two circuits consist of Down-literal circuit(DLC) and combinational logic block(CLC). In the implementation of quaternary inverter circuit, DLC is used for reference voltage generation and control signal, only switch part is implemented with conventional MOS transistors. The proposed circuits are simulated in 0.35 ${\mu}{\textrm}{m}$ N-well doubly-poly four-metal CMOS technology with a single +3V supply voltage. Simulation results of these circuit show 250MHz sampling rate, 0.6mW power consumption and maintain output voltage level in 0.1V.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.12 no.6
• /
• pp.10-21
• /
• 2013

This study suggested combined filtering model to eliminate outlier travel time data in transportation information system, and it was based on Median Absolute Deviation and Voting Rule. This model applied Median Absolute Deviation (MAD) method to follow normal distribution as first filtering process. After that, Voting rule is applied to eliminate remaining outlier travel time data after Median Absolute Deviation. In Voting Rule, travel time samples are judged as outliers according to travel-time difference between sample data and mean data. Elimination or not of outliers are determined using a majority rule. In case study of national highway No. 3, combined filtering model selectively eliminated outliers only and could improve accuracy of estimated travel time.

• Journal of dental hygiene science
• /
• v.7 no.4
• /
• pp.243-249
• /
• 2007

It has passed 40 years since dental hygiene was introduced to Korea. At this time, We hereby demonstrate the findings from the survey on the academic definition and developmental direction of dental hygiene. This survey has been conducted on dental hygiene majoring students, dental clinic hygienists of health & medical care and related professors in the dental field. The findings show that there exists a big disparity in defining the academic scope of dental hygiene among students, clinical dental hygienists of health & medical care and university professors. Accordingly, we suggest that the academic scope of dental hygiene should be explained in a uniform definition. In addition, the results of this survey suggest that they feel that the status of dental hygiene is really behind other study fields, in view of such high response thereto. For development of dental hygiene study and enhancement of its social status, the joint professional study by private, government and scholars should be immediately promoted and a wide variety of programs for dental hygiene should be continuously implemented under the auspices of government and academic world.

• The Journal of Korean Academy of Prosthodontics
• /
• v.56 no.4
• /
• pp.384-390
• /
• 2018

Hybrid telescopic double crown have ever been good treatment option for patient with periodontally unfavorable few remaining teeth for successful prognosis. Tooth and implant combined telescopic double crown can be used for improving retention and support for denture with strategically placed implants on edentulous ridge. In this case, an 55-year-old female patient had chronic periodontitis with few remaining teeth on maxilla and fixed partial prosthodontics on mandible. Treatment of hybrid telescopic double crown with friction pin lasted 9.5 years only with natural teeth. After 9.5 years, additional implants was installed due to fracture of cast-posted abutment teeth. After implantation, tooth and implant combined double crown had fabricated. Through re-treatment, no complications of new denture has been found during 2 years follow up. This case presents fair prognosis of tooth and implant combined double crown denture in periodontally unfavorable condition.