• The KIPS Transactions:PartB
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• v.10B no.1
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• pp.33-40
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• 2003

Data mining plays an important role in a knowledge discovery process and various algorithms of data mining can be selected for the specific purpose. Most of traditional hierachical clustering methode are suitable for processing small data sets, so they difficulties in handling large data sets because of limited resources and insufficient efficiency. In this study we propose a hybrid neural networks clustering technique, called PPC for Pre-Post Clustering that can be applied to large data sets and find unknown patterns. PPC combinds an artificial intelligence method, SOM and a statistical method, hierarchical clustering technique, and clusters data through two processes. In pre-clustering process, PPC digests large data sets using SOM. Then in post-clustering, PPC measures Similarity values according to cohesive distances which show inner features, and adjacent distances which show external distances between clusters. At last PPC clusters large data sets using the simularity values. Experiment with UCI repository data showed that PPC had better cohensive values than the other clustering techniques.

• Restorative Dentistry and Endodontics
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• v.44 no.4
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• pp.37.1-37.10
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• 2019

Objectives: This study evaluated the bond strength of various fiberglass post cementation techniques using different resin-based composites. Materials and Methods: The roots from a total of 100 bovine incisors were randomly assigned to 5 treatment groups: G1, post + Scotchbond Multi-Purpose (SBMP) + RelyX ARC luting agent; G2, relined post (Filtek Z250) + SBMP + RelyX ARC; G3, individualized post (Filtek Z250) + SBMP; G4, individualized post (Filtek Bulk-Fill) + SBMP; G5, individualized post (Filtek Bulk-Fill Flow) + SBMP. The samples were subjected to the push-out (n = 10) and pull-out (n = 10) bond strength tests. Data from the push-out bond strength test were analyzed using 2-way analysis of variance (ANOVA) with the Bonferroni post hoc test, and data from the pull-out bond strength test were analyzed using 1-way ANOVA. Results: The data for push-out bond strength presented higher values for G2 and G5, mainly in the cervical and middle thirds, and the data from the apical third showed a lower mean push-out bond strength in all groups. No significant difference was noted for pull-out bond strength among all groups. The most frequent failure modes observed were adhesive failure between dentine and resin and mixed failure. Conclusions: Fiberglass post cementation using restorative and flowable bulk-fill composites with the individualization technique may be a promising alternative to existing methods of post cementation.

• The Journal of Advanced Prosthodontics
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• v.5 no.2
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• pp.126-132
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• 2013

PURPOSE. Post surface conditioning is necessary to expose the glass fibers to enable bonding between fiber post and resin cement. The purpose of the present study was to evaluate the effect of different surface conditioning on tensile bond strength (TBS) of a glass fiber reinforced post to resin cement. MATERIALS AND METHODS. In this in vitro study, 40 extracted single canal central incisors were endodontically treated and post spaces were prepared. The teeth were divided into four groups according to the methods of post surface treatment (n=10): 1) Silanization after etching with 20% $H_2O_2$, 2) Silanization after airborne-particle abrasion, 3) Silanization, and 4) No conditioning (Control). Adhesive resin cement (Panavia F 2.0) was used for cementation of the fiber posts to the root canal dentin. Three slices of 3 mm thick were obtained from each root. A universal testing machine was used with a cross-head speed of 1 mm/minute for performing the push-out tests. Two-way ANOVA and Tukey post hoc tests were used for analyzing data (${\alpha}$=0.05). RESULTS. It is revealed that different surface treatments and root dentin regions had significant effects on TBS, but the interaction between surface treatments and root canal regions had no significant effect on TBS. There was significant difference among $H_2O_2$ + Silane Group and other three groups. CONCLUSION. There were significant differences among the mean TBS values of different surface treatments. Application of hydrogen peroxide before silanization increased the bond strength between resin cements and fiber posts. The mean TBS mean values was significantly greater in the coronal region of root canal than the middle and apical thirds.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.11
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• pp.1178-1185
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• 2004

In the atmosphere of $N_2$ gas, BaZ $r_{0.08}$ $Ti_{0.92}$ $O_3$ polycrystal was grown by floating zone technique using BaZ $r_{0.08}$ $Ti_{0.92}$ $O_3$ ceramics as a feed and SrTi $O_3$(1l0) single cystal as a seed. The dielectric constant and loss at 10 kHz, 100 kHz, and 1 MHz for the as-grown sample were measured as a function of temperature in the temperature range between -10$0^{\circ}C$ and 150 $^{\circ}C$ to find a dielectric peak with frequency dispersion at Curie point. The hysteresis loop showed that the grown sample had very small polarization which was 0-0.01 $\mu$C/$\textrm{cm}^2$ for the applied dc-electric fields from -7 kV/cm to +7 kV/cm. However, the normal hysteresis loop was appeared after oxygen annealing. The electric-field dependence of the dielectric constant for both the as-grown and the post-annealed samples was studied by measuring the dielectric constants as a function of the biased-electric fields and their tunability was figured out from it at room temperature(27 $^{\circ}C$) and cryotemperature( -73$^{\circ}C$). Tunability for the as-grown sample was 51 % and the figure of merit 20.4 at 10kHz with the biased electric-field of 12 kV/cm. The tunability for the grown sample may be increased up to 80 % if the electric field of 25 kV/cm is applied. Tunability for the post-annealed sample was 41 % and the figure of merit 10.3 at 10 kHz with the biased electric-field of 12 kV /cm. Post-annealing improved the crystallinity of the as-grown sample but decreased its tunability.ability.

• Journal of Yeungnam Medical Science
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• v.6 no.2
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• pp.71-78
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• 1989

Horizontal mattress suture technique on microvascular anastomosis of rat(body weight : 200-250gm) femoral artery was evaluated. The present study was conducted to compare the horizontal mattress suture with simple interrupted suture on the suture time, patency rate of the sutured vessels, and the histological changes of surgical site of the vessel wall during wound healing period. The mean suture time of the vessel wall with horizontal mattress suture technique was 15min. 49sec. ${\pm}$ 2.14, which is significantly shorter than that of simple interrupted suture technique. The patency rate of the sutured vessel in both groups was statistically not different each other till post-operative 3rd day but patency rate of horizontal mattress suture was higher than that of simple interrupted suture at post-operative 3rd week. The histological findings such as intimal noss, medial degenention and intimal regeneration were similar in both groups.

• Clinical and Experimental Reproductive Medicine
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• v.27 no.1
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• pp.99-105
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• 2000

Objective: The objective of this study was to compare results of the macroscopic one-layer vasovasostomy with those of microscopic one-layer vasovasostomy and to analyze the change of semen parameters according to the interval of vasal obstruction. Method and Materials: Between March 1987 and December 1997, we performed 121 vasovasostomies using modified one-layer technique with loupe magnification (macroscopic vasovasostomy) or microscope. Among the 68 could be followed post-operatively, 37 patients were treated by macroscopic technique with loupe, and 31 patients by microscopic technique. We compared rates of anatomical patency (sperm count above than $10{\times}10^{6}$/ml) and pregnancy of macroscopic vasovasotomy with those of microscopic vasovasostomy. Patency and pregnancy rates according to vasal obstructive interval were also examined. Results: The patency rates of macroscopic and microscopic technique were 86.5% and 87.1%, and pregnancy rates of macroscopic and microscopic technique were 64.9% and 67.7%. There was no statistical significance between these two methods (p>0.05). The pregnancy rates and sperm motility were decreased if more than 10 years had elapsed following vasectomy (p<0.05). Conclusion: We found little difference in success rates resulting from macroscopic and microscopic vasovasostomy and the former had the advantage of reduced cost and a lower operator skill level. In post-operative semen analysis, the sperm motility was the most probable factor associated with vasal obstructive interval.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.31 no.6
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• pp.485-491
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• 2009

Postoperative skeletal stability was evaluated in combination of Le Fort I and U-shaped osteotomies for superior repositioning of maxilla in bi-maxillary surgeries in 30 consecutive patients. The fifteen patients underwent Le Fort I osteotomy alone and the other fifteen patients underwent Le Fort I and U-shaped osteotomies. In all patients, the maxilla was first osteomized and fixed with absorbable plates system. A bilateral sagittal split ramus osteotomy (BSSRO) of the mandible was then carried out and fixation was performed using absorbable plates. Maxillo-mandibular fixation with rubber ring was used for two weeks post-operatively in all patients. Lateral cephalograms were obtained pre-operatively, 1 day post-operatively, 6 months after surgery. The changes in anterior nasal spine (ANS), point A, upper incisior (U1), and point of maxillary tuberosity (PMT) were examined. The maxillas in the fifteen patients of both examination group were repositioned nearly in their planned positions during surgery and no significant post-operative changes in the examined points of the maxilla were found. These results suggest that a combination of a Le Fort I and U-shaped osteotomy is a useful technique for reliable superior repositioning of the maxilla. The post-operative change in the maxilla using this combination osteotomy was comparatively stable.

• The Korean Journal of Pain
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• v.8 no.1
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• pp.31-36
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• 1995

Post-tonsillectomy pain in children is a difficult problem to manage. We examined the effect of 10% aerosol lidocaine for the post-tonsillectomy analgesia. ASA physical status I or II, between five and thirteen years of age were assigned, in a randomized fashion, into two groups. The Group I, 30 patients, received a total dose of 4 mg/kg of ten percent aerosol lidocaine on the tonsillar beds. Lidocaine was administered at the end of the surgical procedure. The Group II, 30 patients, were not sprayed with lidocaine aerosol. The postoperative pain scores were assessed by a "red and white" visual analoge pain scales (VAPS). VAPS values were obtained at one and eight hours after the operation. Values of one hour after the operation in the group I and II were $20.83{\pm}10.01$ and $34.50{\pm}10.53$, values of eight hours after the operation were $17.33{\pm}9.07$ and $23.5{\pm}11.08$. The post-tonsilectomy pains were significantly lower in the group I compared with the group II at one and eight hours after the operation. In conclusion, 4 mg/kg of ten percent aerosol lidocaine applied directly on the tonsillar beds was showen a superior, immediate post-tonsillectomy analgesic technique.

• The Journal of the Korean dental association
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• v.51 no.11
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• pp.595-603
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• 2013

The requirements for the successful treatment of all-ceramic restorations are not so different from the ones of conventional restorations. "The provisional restoration followed by an adequate tooth reduction and the accurately fitting prostheses with corresponding to final impression" can be the examples of them. Nevertheless, the one which all-ceramic restorations are distinguished from conventional restorations is the additional procedure of so called "bonding". In addition to the application of resin cement between "inner surface of restoration and outer surface of abutment", bonding technology can be also applied to the treatment process of "Post and Core" in particular if the abutments are non-vital teeth. Core build-up for all-ceramic crown is conducted with fiber post and tooth colored composite by considering the properties of the restorations transmitting light. We know well that a vital abutment is easier than a non-vital one to get the targeted goals for clinical success in connection with esthetics and structure. The creation of "Post and Core" with bonding technique is a decisive factor for a long-term success if the abutment is non-vital tooth with dentinal collapse. I would like to share my clinical experience about "post & core build-up and all-ceramic restoration bonding" out of several success strategies of all-ceramic crown with this presentation.

• Structural Engineering and Mechanics
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• v.85 no.3
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• pp.419-432
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• 2023

This paper studies the effects of porosity distributions on buckling and post-buckling behaviors of a functionally graded saturated porous (FGSP) circular plate. The plate is under the uniformly distributed radial loading and simply supported and clamped boundary conditions. Pores are saturated with compressible fluid (e.g., gases) that cannot escape from the porous solid. Elastic modulus is assumed to vary continuously through the thickness according to three different functions corresponding to three different cases of porosity distributions, including monotonous, symmetric, and asymmetric cases. Governing equations are derived utilizing the classical plate theory and Sanders nonlinear strain-displacement relations, and they are solved numerically via shooting method. Results are verified with the known results in the literature. The obtained results for the monotonous and symmetric cases with the asymmetric case presented in the literature are shown in comparative figures. Effects of the poroelastic material parameters, boundary conditions, and thickness change on the post-buckling behavior of the plate are discussed in details. The results reveal that buckling and post-buckling behaviors of the plate in the monotonous and symmetric cases differ from the asymmetric case, especially in small deflections, that asymmetric distribution of elastic moduli can be the cause.