• The Journal of Advanced Prosthodontics
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• 제12권3호
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• pp.173-180
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• 2020

PURPOSE. This study compared digital (reference point matching) and replica methods for measuring marginal and internal fit of full coverage restorations. MATERIALS AND METHODS. A maxillary left first molar typodent was fixed on to an aluminum base and prepared to receive all-ceramic full coverage restoration. The model was scanned with an intraoral scanner (CEREC Omnicam, Sirona, York, PA, USA). Twelve crowns were fabricated from lithium disilicate blocks (IPS emax CAD, Ivoclar Vivadent) and then crystalized. Marginal and internal fit of each restoration was measured by two examiners using replica and a new digital three-dimensional technique. Reliability between the two methods and two examiners was assessed by correlation and Cronbach's Alpha coefficient (P<.05). A Bland-Altman assessment for agreement was used to compare the two methods. RESULTS. Bland-Altman assessment showed that the mean of difference for marginal, absolute marginal, and axial gap was respectively -1.04 ㎛, -41.9 ㎛, and -29.53 ㎛ with limit of agreement (LOA) between -37.26 to 35.18 ㎛ for marginal, -105.85 to 22.05 ㎛ for absolute marginal and -80.52 to 22.02 ㎛ for axial gap. Positive correlation for repeatability (P<.05) in determining marginal and internal gaps by the two examiners in both techniques was revealed. Reliability of both techniques in all sites of measurements was at least good (0.8 ≤ α < 0.9). CONCLUSION. Both measuring techniques appeared highly reliable for evaluating fit of fixed dental restorations, while reference point matching provided higher values in axial and absolute marginal gap assessment.

• 한국치위생학회지
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• 제12권6호
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• pp.1221-1231
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• 2012

Objectives : The purpose of this study was to examine the oral health behavior and examine closely the connection factor and plans oral health promotion. Methods : This survey was conducted on 370 high school students in Kyunggi-do Suwon from November 21 to 23, 2011. 352 questionnaires were collected and analyzed. The collected data was analyzed using the statistical package SPSS WIN 15.0 using frequency, mean and standard deviation analysis, T-test, one-way ANOVA and Duncan's test correlation analysis. Results : The results state that 73.3% of students believe brushing teeth is very important and 26.7% of the students method of tooth brushing is up and down. for correct teeth brushing, they think choosing a brush is important(70.7%) also their brush shapes were uneven form(44.3%) and flat form(43.5%). 31.4% of students are using an oral hygiene device and 31.4% of students had received oral health education. 42.7% of female students get information about oral health from their dental clinics. 24.8% of male students receive information on oral health from parents and relatives. They think the best educator for oral health education will be a Dental hygienist(46.5%), or Dentist(48.0%). we found that a correlation between oral health interest, importance, knowledge and condition effect each other(p<.001). It means that if students have high oral health interest, oral care importance and oral health knowledge which can improve their oral health condition. Conclusions : The results of this study state that we need continuous oral health education systems and prevention programs to raise awareness among students and for the improvement of their oral health.

• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 2008년도 한국우주과학회보 제17권2호
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• pp.37.2-37.2
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• 2008

Korea-Japan Joint VLBI Correlator (KJJVC), to be used for Korean VLBI Network (KVN) in Korea Astronomy & Space Science Institute (KASI), is a high-speed calculator that outputs the correlation results in the maximum speed of 1.4GB/sec.To receive and record this data keeping up with this speed and with no loss, the design of the software running on the data archive system for receving and recording the output data from the correlator is very important. But, the simple kind of programming using just single thread that receives data from network and records it by turns, can cause a bottleneck effect while processing high speed data and a probable data loss, and cannot utilize the merit of hardwares supporting multi core or hyper threading, or operating systems supporting these hardwares. In this talk we summarize the design of the data transfer software for KJJVC and high speed, large capacity data archive system using general socket programming and multi threading techniques, and the pre-BMT(Bench Marking Test) results from the tests of the storage product providers' proposals using this software.

• 가족자원경영과 정책
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• 제18권1호
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• pp.1-28
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• 2014

The purpose of this study is to suggest how the first birthday rite, a practice in Korean culture, has changed over the time. A survey of 250 mothers was undertaken from October 11th to November 6th, 2012. The research questions asked in this study are as follows. What general and expert views are held about the first birthday rite? What type of awareness and knowledge do mothers have about the first birthday rite? Is there any correlation between mothers' awareness and knowledge about first birthday rite? What is the importance of the components of the baby's first birthday rite and the importance of choosing first birthday rite goods? The data were analyzed using SPSS 17.0. Frequency, F-test, correlation were also employed. The results of this study are as follows: The first birthday rite shows a clear link to socializing. It is a family event, but is also seen as an opportunity to enhance relationships with relatives, colleagues, and friends. A banquet hall is chosen as preferred first birthday rite location, and participants are served a meal and receive gifts. The banquet information on first birthday rites was initially collected from the internet, blog cafes, and an experienced. However, it has become gradually more common to hire a consultant to organize the first birthday rite. Awareness of the first birthday rite is high, but knowledge is relatively low. In addition, there is a positive relationship between awareness and knowledge about the first birthday rite. When mothers are preparing for their baby's first birthday, they consider food for the guests' banquet, space and time. Finally, individual positive relationships were found between choosing first birthday rite goods and employee services, contract pricing for goods, and food for guests.

• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
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• 제9권5호
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• pp.521-529
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• 2003

본 논문에서는 추천시스템에서 많이 활용되는 협업 여과 방법의 문제점으로 지적되고 있는 희소성(sparsity)으로 인한 유사도의 부정확한 문제를 개선하기 위하여, 인구 통계 정보를 이용한 기법을 제안하였다. 두 사용자간의 유사도는 같은 항목에 동시에 평가된 점수를 기반으로 결정되며, 두 사용자가 동시에 평가하지 않은 항목은 유사도 계산에서 제외된다. 제안된 기법은 이러한 평가 점수 부족으로 인하여 유사도 계산이 정확치 못한 단점을 보완하기 위하여, 인구 통계 정보를 이용한 가상 평가 점수를 부가하여 유사도 계산을 개선, 예측의 정확도를 향상시킨 방식으로 기존의 피어슨 상관관계를 이용한 협업여과 방식의 확장이다. 실험은 Grouplens의 영화 평가 자료를 활용하였고, 평균절대오차(MAE)와 반응자 작용특성(ROC)값을 이용하여 제안 기법과 피어슨 상관관계를 이용한 협업 여과 방식을 비교하였다. 제안한 기법이 피어슨 상관관계를 이용한 협업 여과 추천 방식에 비하여 평균절대오차는 9%, 반응자 작용 특성의 민감도는 13% 향상되었음을 확인하였다.

• 한국컴퓨터정보학회논문지
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• 제12권1호
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• pp.155-160
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• 2007

고속 데이터 전송에 적합한 Multi-Code CDMA 시스템은 출력이 Multi-Level이 됨으로써 출력신호의 복잡성과 출력단에 선형적인 증폭기를 사용하므로 고가, 고복잡성 등의 단점을 가진다. 이러한 단점을 보완하고자 기존 CDMA 기술에 기반을 둔 Binary CDMA 기술이 제안되었다. Binary CDMA 시스템에서 고속 데이터 연산 시 병목현상이 발생되는 코릴레이터는 동기획득시 매우 중요한 파라미터이다. 기존의 코릴레이터는 전력소모가 작다는 장점이 있지만 코릴레이션의 값을 얻기 위해 여러단의 가산을 거쳐야 하므로 연산량이 많아 처리 속도가 낮은 단점을 가지고 있다. 그러므로 본 논문은 Binary CDMA 시스템에서 고속의 데이터를 처리할 수 있으며 데이터 량이 증가하더라도 칩 면적이 독립적이며 전력소모가 일정한 구조를 가지는 코릴레이터를 제안하였다.

• 한국토양비료학회지
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• 제47권4호
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• pp.235-241
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• 2014

A ground-based microwave scatterometer has an advantage for monitoring soil moisture content using multi-polarization, multi-frequencies and various incidence angles. In this paper, ground-based multi-frequency (L-, C-, and X-band) polarimetric scatterometer system capable of making observations every 10 min was used to monitor the soil moisture conditions in a corn field over an entire growth cycle. Measurements of volumetric soil moisture were obtained and their relationships to the backscatter observations were examined. Time series of soil moisture content was not corresponding with backscattering coefficient pattern over the whole growth stage, although it increased until early July (Day Of Year, DOY 160). We examined the relationship between the backscattering coefficients from each band and soil moisture content of the field. Backscattering coefficients for all bands were not correlated with soil moisture content when considered over the entire stage ($r{\leq}0.48$). However, L-band Horizontal transmit and Horizontal receive polarization (HH) had a good correlation with soil moisture ($r=0.85^{**}$) when LAI was lower than 2. Prediction equations for soil moisture were developed using the L-HH data. Relation between L-HH and soil moisture shows linear pattern and related with soil moisture content ($R^2=0.77$). Results from this study show that backscattering coefficients of microwave scatterometer appear to be effective to estimate soil moisture content in the field level.

• 한국학교ㆍ지역보건교육학회지
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• 제20권2호
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• pp.37-51
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• 2019

Purpose: This study aims to substantiate a correlation between the period of living alone in a shabby one-room and a depression experience. Methods: We conducted a cross-sectional study using data from the Korea Homeless Survey carried out by the Korea Institute for Health and Social Affairs in 2016. In the study, the data included 485 survey participants who resided in a single room. The period of single-room occupancy being divided into three groups: less than 1 year, 1 to 4 years, and more than 5 years was considered a primary independent variable. The outcome variable which represented a depression experience was measured by CESD-11(The Center for Epidemiological Studies-Depression Scale). We carried out a Chi-square test and multiple logistic regression to evaluate the association. Results: The rate of depression experienced in this population was 77.5%. Almost 83.9% of the participants were reported as being unable to receive the mental health counselling in the last 12 months. After controlling for covariates, subjects who were living in a single room occupancy for 1-5 years(OR=3.89; 95% CI=1.43-10.56) and more than 5 years(OR=2.71; 95% CI= 1.05-6.95) were found to be more likely to experience depression. Conclusions: The results showed that living alone in a shabby one-room had a high correlation with experiencing depression. We proposed that there is a need to develop a new strategy for mental health promotion program for the poor, vulnerable and deprived population.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권3호
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• pp.838-856
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• 2014

Enhanced network speed and the appearance of various applications have recently resulted in the rapid increase of Internet users and the explosive growth of network traffic. Under this circumstance, Internet users are eager to receive reliable and Quality of Service (QoS)-guaranteed services. To provide reliable network services, network managers need to perform control measures involving dropping or blocking each traffic type. To manage a traffic type, it is necessary to rapidly measure and correctly analyze Internet traffic as well as classify network traffic according to applications. Such traffic classification result provides basic information for ensuring service-specific QoS. Several traffic classification methodologies have been introduced; however, there has been no favorable method in achieving optimal performance in terms of accuracy, completeness, and applicability in a real network environment. In this paper, we propose a method to classify Internet traffic as the first step to provide stable network services. We integrate the existing methodologies to compensate their weaknesses and to improve the overall accuracy and completeness of the classification. We prioritize the existing methodologies, which complement each other, in our integrated classification system.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권3호
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• pp.941-955
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• 2015

In dual-channel networks (DCNs), all frequency hopping (FH) sequences used for data channels are chosen from the original FH sequence used for the control channel by shifting different initial phases. As the number of data channels increases, the hitting frequency point problem becomes considerably serious because DCNs is non-orthogonal synchronization network and FH sequences are non-orthogonal. The increasing severity of the hitting frequency point problem consequently reduces the resource utilization efficiency. To solve this problem, we propose a novel hitting frequency point collision avoidance method, which consists of a sequence-selection strategy called sliding correlation (SC) and a collision avoidance strategy called keeping silent on hitting frequency point (KSHF). SC is used to find the optimal phase-shifted FH sequence with the minimum number of hitting frequency points for a new data channel. The hitting frequency points and their locations in this optimal sequence are also derived for KSHF according to SC strategy. In KSHF, the transceivers transmit or receive symbol information not on the hitting frequency point, but on the next frequency point during the next FH period. Analytical and simulation results demonstrate that unlike the traditional method, the proposed method can effectively reduce the number of hitting frequency points and improve the efficiency of the code resource utilization.