• The Journal of Korean Academy of Prosthodontics
• /
• v.39 no.3
• /
• pp.260-272
• /
• 2001

All-ceramic restorations have had a more limited life expectancy than metal ceramic restorations because of their low strength. Their relatively lower strength and resistance to fracture have restricted the use of all-ceramic crowns to anterior applications where occlusal loads are lower. But there has been increasing interest in all-ceramic restorations because patients are primarily concerned with improved esthetics. Many efforts have been made to in prove the mechanical properties of dental ceramics. This study was designed to elucidate the influence of the luting agent on the strength of the Empress 2 crown (staining technique) cemented on human teeth. Seventy extracted human permanent molar teeth were chosen. Teeth were prepared for Empress 2 crowns with milling machine on a surveyor. A dental bur was placed in the mandrel that was positioned so that the long axis of the bur was perpendicular to the surveyor base. Dimensions of the Empress 2 crown preparation were $6^{\circ}$ taper on each side, $1.5{\pm}0.1mm$ shoulder margin, and 4mm crown height. The luting cements used in this study were as follow: 1. Uncemented 2. Zinc phosphate cements (Confi-Dental) 3. Conventional glass ionomer cement : Fuji 1 (GC) 4. Resin-modified glass ionomer cements : Fuji plus (GC) 5. Adhesive cements : Panavia F (Kuralay), Variolink II (Vivadent), Choice (Bisco). Fracture test using Instron. The crowns were loaded in compressive force to evaluate the effect of these cements on the breaking strength of these all-ceramic crowns. A steel ball with a diameter of 4mm was placed on the occlusal surface and load was applied to the steel ball by a cylindrical bolt with a crosshead speed of 0.5mm per minute until fracture occurred. The fractured surface was examined using Scanning Electron Microscopic Image (SEM) to discover the correlation between fracture strength and bonding capacity. Within the limitation of this in vitro study design, the results were as follows : 1. fomentations significantly increased the fracture resistance of Empress ceramic crowns compared to control. Uncemented (206.9 N): ZPC (812.9 N): Fuji 1 (879.5 N): Fuji Plus (937.7 N): Choice (1105.4 N): Variolink II (1221.1 N): Panavia F (1445.2 N). 2. Resin luting agent, treated by a silane bond enhancing agents, yielded a significant increase in fracture resistance. In some of the Panavia F group, a fracture extended into dentin. 3. According to SEM images of fractured Empress crowns, the stronger the bond at both interfaces(crown and die), the more fracture strength was acquired.

• KSBB Journal
• /
• v.24 no.4
• /
• pp.410-414
• /
• 2009

Single-nucleotide polymorphisms (SNPs) are the DNA sequences difference among the same species in the level of nucleic acids and are widely applied in clinical fields such as personalized medicine. The routine and labor-intensive methods to determine SNPs are performing the sequence homology search by using BLAST and navigating the trace of chromatogram files generated by high-throughput DNA sequencing machine by using Chromas program. In this paper, we developed SNPchaser, a web-based program for detecting SNPs substitution and heterozygosity existence, to improve the labor-intensive method in determining SNPs. SNPchaser performed sequence alignment and visualized the suspected region of SNPs by using user's reference sequence, AB1 files, and positional information of SNPs. It simultaneously provided the results of sequences alignment and chromatogram of relevant area of SNPs to user. In addition, SNPchaser can easily determine existence of heterozygosity in SNPs area. SNPchaser is freely accessible via the web site http://www.bioinformatics.ac.kr/SNPchaser and the source codes are available for academic research purpose.

• Korean journal of applied entomology
• /
• v.24 no.4 s.65
• /
• pp.231-238
• /
• 1986

Molecular orbital theoretical study on the stability of conformations and chemical reactivity of 0,0-diethylphenylphosphate derivatives were carried out by EHT and CNDO/2 molecular orbital calculation method. The results shown that the dipole moment(${\mu}$) and total energies of the ${\theta}=90^{\circ}$ conformer were ${\mu}=3.185D\;&\;E_t=-162.6479(au)$ and also that of the ${\theta}=0^{\circ}$ conformer were ${\mu}=5.596D\;&\;E_t=-162.4013(au)$, respectively. Therefore, the values of ${\mu}\;&\;E_t$ of the ${\theta}=90^{\circ}$ conformer were much smaller than that of the ${\theta}=0^{\circ}$ conformer. The form with angle of rotation ${\theta}=90^{\circ}$ of phenyl ring was shown to be most stable and this was interpreted in terms of electrostatic and steric effect. 0,0-diethylphenylphosphate derivatives are predicted to increase both charge and orbital controlled $SN_2$ reactivity of the electron withdrawing substituent reduces the HOMO & LUMO energy, while the electron withdrawing substituent due to increase in positive charge of phosphorus atom of phosphate molecule.

• The Korean Journal of Community Living Science
• /
• v.16 no.1
• /
• pp.149-163
• /
• 2005

Family has emerged as a key concept for health, and it has been identified as one of the most important conditions. The relationship between health habit and its management is different depending on family. The odd pair family, mostly rural lower income class, worry to have poor health because of no spouse and small family size. One thousand eight hundred and seventy(1870) subjects were collected in 9 provinces through the sampling of Probability Proportional to Size (PPS). Questionnaire method was conducted on health checking, bath states, alcohol consumption, cigarette smoking, and the prevalence of farmer's health related problems. The main results were as follows: 1) The characteristics of odd pair families are that the head of household is female(77% ), the size of family is small(1.76 persons), the education level is low(7.5 years for male, 3.1 years for female) and the age group is old (male: 89.78 year old, female: 73.69 year old). 2) For the odd pair family, the frequency of health checking is quite low with one or two times per year(l0.2%) and the rate of no-health checking is much higher(35.8%) .3) Bathing utility is not available 29.6% of the odd pair family and only cold water is supplied at home for the 11.5 % of them. However, for the paired family, 9.8 % of them has no bathing utility and the rate of the family supplied with only cold water is just 7.9%. 4) The bathing frequency score of odd pair family is l.74points for male and 1.25 points for female. 5) The rate of smoking habits for odd pair family is 68.5 % and specially it is 7.6% for female, which is higher comparing with that of pair family. 6) The smoking frequency score of odd pair family is 1.57 points. 7) Alcohol drinking frequency score of odd pair family is 1.79 points for male, and 3.24points for female. 8) Farmers' syndrome(FS) revealed 38.7% of odd pair family and it is lower than that of pair family(57.3%). Special pain of FS was huckle bone and muscle(28.4%) and articular pain(24.l %). The pain rate of huckle bone and muscle(43.l %) and articular pain(33.5%) were higher in a year in odd pair family were lower than those of pair family: farming machine caused accidents(6.5%) and pesticide poisoning(5.7%). l0) The odd pair family use more frequently medical clinic or public health center for the treatment of FS(74.7%) and pesticide poisoning(62.5%) than the pair family for FS(69.0%) and for pesticide poisoning(.53.6%). The score of FS treatment is 5.70 points for odd pair family and it is not significantly different from 5.62 points of the paired family. The result of pesticide poisoning treatment score is as same as that of FS.

• Journal of IKEEE
• /
• v.15 no.4
• /
• pp.354-362
• /
• 2011

One of the unsolved problems in Artificial Neural Networks is related to the capacity of a neural network. This paper presents a CoreNet which has a multi-leveled input and a multi-leveled output as a 2-layered artificial neural network. I have suggested an equation for calculating the capacity of the CoreNet, which has a p-leveled input and a q-leveled output, as $a_{p,q}=\frac{1}{2}p(p-1)q^2-\frac{1}{2}(p-2)(3p-1)q+(p-1)(p-2)$. With an odd value of p and an even value of q, (p-1)(p-2)(q-2)/2 needs to be subtracted further from the above equation. The simulation model 1(3)-1(6) has 3 levels of an input and 6 levels of an output with no hidden layer. The simulation result of this model gives, out of 216 possible functions, 80 convergences for the number of implementable function using the cot(x) input leveling method. I have also shown that, from the simulation result, the two diverged functions become implementable by precalculating the weight values. The simulation result and the precalculation of the weight values give the same result as the above equation in the total number of implementable functions.

• Korean Journal of Optics and Photonics
• /
• v.24 no.6
• /
• pp.331-337
• /
• 2013

A large optical surface is fabricated by grinding, polishing and figuring. The grinding process is the most rapid and has the largest amount of fabrication of all processes. If we measure the surface precisely and rapidly in the grinding process, it is possible to improve the efficiency of the fabrication process. Since the surface of grinding process is rough and not shiny, it is not easy to measure the surface using light so that we cannot use an interferometer. Therefore, we have to measure the surface using a mechanical method. We can measure the surface under the grinding process by using a laser tracker which is a portable 3-dimensional coordinate measuring machine. In this paper, we used the laser tracker to measure the surface error of 1 m diameter spherical mirror. This measurement result was compared to that of an interferometer. As a result, surface measurement error was found to be $0.2{\mu}m$ rms (root mean square) and $2.7{\mu}m$ PV (Peak to Valley), which is accurate enough to apply to the rough surface under the grinding stage.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.23 no.4
• /
• pp.292-303
• /
• 2011

A new type of sand bypassing system is proposed for recovering the eroded beach in this study. This system provides an added methodology to the soft defence which is main recovery method for the coastal shore protection in the world. The study proposes a conceptional design and manufacturing procedure for the relatively small size machine of sand bypassing. In order to get the discharging volume information, the power capacity of the system is tested in the field. The discharge rate of the new system shows up to the expected maximum of 618 ton/hr which is 9.6% lower than that by theoretical calculation. It gives a resonable agreement in this system when the flow is assumed to be of the high density. In this study, the delivering volume of sand is estimated according to the discharge rate. The combination of 300 mm(12 inch) intake and 250 mm(10 inch) discharge pipe line has the pumping capacity of $103\;m^3/hr$ which is nearly the same as that of South Lake Worth Inlet sand bypassing system, Florida, U.S.A.. The proposed system added the mobility to its merit. The unit price of Florida's sand bypassing is $$8~9/m^3$ (US). The system would be economically suitable for small volume of sand because no additional equipment is necessary for the intake. The diesel fuel of 25~30 l/hr was consumed during the system operation. The multiple working system would be the next investigation target for large volume of sand.

• Journal of the Korea Society of Computer and Information
• /
• v.15 no.12
• /
• pp.197-207
• /
• 2010

Using a variety of data-mining methods on high-throughput cDNA microarray data, the level of gene expression in two different tissues can be compared, and DEG(Differentially Expressed Gene) genes in between normal cell and tumor cell can be detected. Diagnosis can be made with these genes, and also treatment strategy can be determined according to the cancer stages. Existing cancer classification methods using machine learning select the marker genes which are differential expressed in normal and tumor samples, and build a classifier using those marker genes. However, in addition to the differences in gene expression levels, the difference in gene-gene correlations between two conditions could be a good marker in disease diagnosis. In this study, we identify gene pairs with a big correlation difference in two sets of samples, build gene classification modules using these gene pairs. This cancer classification method using gene modules achieves higher accuracy than current methods. The implementing clinical kit can be considered since the number of genes in classification module is small. For future study, Authors plan to identify novel cancer-related genes with functionality analysis on the genes in a classification module through GO(Gene Ontology) enrichment validation, and to extend the classification module into gene regulatory networks.

• Journal of Wetlands Research
• /
• v.21 no.4
• /
• pp.312-320
• /
• 2019

The occurrence of cyanobacteria causes problems such as oxygen depletion and increase of organic matter in the water body due to mass prosperity and death. Each year, Algae bloom warning System is issued due to the effects of summer heat and drought. It is necessary to quantitatively characterize the occurrence of cyanobacteria for proactive green algae management in the main Nakdong river. In this study, we analyzed the major influencing factors on cyanobacteria bloom using visualization and correlation analysis. A decision tree, a machine learning method, was used to quantitatively analyze the conditions of cyanobacteria according to the influence factors. In all the weirs, meteorological factors, temperature and SPI drought index, were significantly correlated with cyanobacterial cell number. Increasing the number of days of heat wave and drought block the mixing of water in the water body and the stratification phenomenon to promote the development of cyanobacteria. In the long term, it is necessary to proactively manage cyanobacteria considering the meteorological impacts.

• Journal of Cadastre & Land InformatiX
• /
• v.50 no.1
• /
• pp.75-85
• /
• 2020

This study examines machine learning cross-validation to utilized create ROI for classification of land cover. The study area located in Sejong and one KOMPSAT-3A image was used in this analysis: procedure on October 28, 2019. We used four bands(Red, Green, Blue, Near infra-red) for learning cross validation process. In this study, we used K-fold method in cross validation and used SVM kernel type with cross validation result. In addition, we used 4 kernels of SVM(Linear, Polynomial, RBF, Sigmoid) for supervised classification land cover map using extracted ROI. During the cross validation process, 1,813 data extracted from 3,500 data, and the most of the building, road and grass class data were removed about 60% during cross validation process. Based on this, the supervised SVM linear technique showed the highest classification accuracy of 91.77% compared to other kernel methods. The grass' producer accuracy showed 79.43% and identified a large mis-classification in forests. Depending on the results of the study, extraction ROI using cross validation may be effective in forest, water and agriculture areas, but it is deemed necessary to improve the distinction of built-up, grass and bare-soil area.