• Journal of Korean Foot and Ankle Society
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• v.5 no.1
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• pp.35-42
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• 2001

Purpose: To analyze the results of conservative or surgical treatment after computed tomograhy(CT) classification in intraarticular calcaneal fractures. Materials and methods: From January 1996 to May 1999, we prospectively analyze 23 cases of intraarticular calcaneal fractures who were treated conservatively or operated by open reduction and internal fixation by extensive L-shaped lateral approach after CT classification. Results: A functional scoring system of 0-100 points which was based upon the responses to AOFAS Ankle-Hindfoot Scale for the operative group was at 82.8, compared with 73.2 for the non-operative group, and these were meaningful statistically(P<0.05). Of type I fracture, in the operative group there were 2 excellent results and in the non-operative group there were 2 excellent results, 1 good result. or type II fractures, in the operative group there were 2 excellent results, 3 good results, 1 fair result and in the non-operative group there were 1 good result, 1 fair result, 2 poor results. Of type III fractures, in the operative group there were 2 fair results, 2 poor results and in the non-operative group there were 1 fair result, 3 poor results. Bohler angles of subtalar joint were changed from initial average $13.3^{\circ}$ to postoperative average $20.9^{\circ}$ for the operative group compared with from initial average $15.5^{\circ}$ to follow-up average $14.8^{\circ}$ of the non-operative group(P<0.01). Conclusions: Computed tomography in the evaluation of intraarticular calcaneal fractures is effective tool. We believed that open reduction and internal fixation in all Crosby & Fitzgibbons type II and according to degrees of comminution reducible type III for the intraarticular calcaneal fractures is more effective method than conservative treatment.

• Ocean Systems Engineering
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• v.12 no.3
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• pp.359-384
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• 2022

We develop in this work a new well-balanced preserving-positivity path-conservative central-upwind scheme for Saint-Venant-Exner (SVE) model. The SVE system (SVEs) under some considerations, is a nonconservative hyperbolic system of nonlinear partial differential equations. This model is widely used in coastal engineering to simulate the interaction of fluid flow with sediment beds. It is well known that SVEs requires a robust treatment of nonconservative terms. Some efficient numerical schemes have been proposed to overcome the difficulties related to these terms. However, the main drawbacks of these schemes are what follows: (i) Lack of robustness, (ii) Generation of non-physical diffusions, (iii) Presence of instabilities within numerical solutions. This collection of drawbacks weakens the efficiency of most numerical methods proposed in the literature. To overcome these drawbacks a reformulation of the central-upwind scheme for SVEs (CU-SVEs for short) in a path-conservative version is presented in this work. We first develop a finite-volume method of the first order and then extend it to the second order via the averaging essentially non oscillatory (AENO) framework. Our numerical approach is shown to be well-balanced positivity-preserving and shock-capturing. The resulting scheme could be seen as a predictor-corrector method. The accuracy and robustness of the proposed scheme are assessed through a carefully selected suite of tests.

• Restorative Dentistry and Endodontics
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• v.43 no.2
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• pp.16.1-16.9
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• 2018

Objectives: Understanding the reason for an unsuccessful non-surgical endodontic treatment outcome, as well as the complex anatomy of the root canal system, is very important. This study examined the cross-sectional root canal structure of mandibular first molars confirmed to have failed non-surgical root canal treatment using digital images obtained during intentional replantation surgery, as well as the causative factors of the failed conventional endodontic treatments. Materials and Methods: This study evaluated 115 mandibular first molars. Digital photographic images of the resected surface were taken at the apical 3 mm level and examined. The discolored dentin area around the root canal was investigated by measuring the total surface area, the treated areas as determined by the endodontic filling material, and the discolored dentin area. Results: Forty 2-rooted teeth showed discolored root dentin in both the mesial and distal roots. Compared to the original filled area, significant expansion of root dentin discoloration was observed. Moreover, the mesial roots were significantly more discolored than the distal roots. Of the 115 molars, 92 had 2 roots. Among the mesial roots of the 2-rooted teeth, 95.7% of the roots had 2 canals and 79.4% had partial/complete isthmuses and/or accessory canals. Conclusions: Dentin discoloration that was not visible on periapical radiographs and cone-beam computed tomography was frequently found in mandibular first molars that failed endodontic treatment. The complex anatomy of the mesial roots of the mandibular first molars is another reason for the failure of conventional endodontic treatment.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.17 no.4
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• pp.351-363
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• 2004

Equation of motion of non conservative system considering mass matrix, elastic stiffness matrix, load correction stiffness matrix by circulatory force's direction change and Winkler and Pasternak foundation stiffness matrix is derived. Also stability analysis due to the divergence and flutter loads is performed. And the influence of internal and external damping coefficient on flutter load is investigated applying the quadratic eigen problem solution. Additionally the influence of non-conservative force's direction parameter, internal and external damping and Winkler and Pasternak foundation on the critical load of Beck's and Leipholz's and Hauger's columns are investigated.

• Steel and Composite Structures
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• v.6 no.2
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• pp.87-101
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• 2006

The deformation and dynamic behavior mechanism of submerged shell-like lattice structures with membranes are in principle of a non-conservative nature as circulatory system under hydrostatic pressure and disturbance forces of various types, existing in a marine environment. This paper deals with a characteristic analysis on quasi-periodic and chaotic behavior of a circular arch under follower forces with small disturbances. The stability region chart of the disturbed equilibrium in an excitation field was calculated numerically. Then, the periodic and chaotic behaviors of a circular arch were investigated by executing the time histories of motion, power spectrum, phase plane portraits and the Poincare section. According to the results of these studies, the state of a dynamic aspect scenario of a circular arch could be shifted from one of quasi-oscillatory motion to one of chaotic motion. Moreover, the correlation dimension of fractal dynamics was calculated corresponding to stochastic behaviors of a circular arch. This research indicates the possibility of making use of the correlation dimension as a stability index.

• The Journal of the Korean dental association
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• v.58 no.11
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• pp.683-689
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• 2020

Dentin surface of non-carious lesion is usually attached with oral biofilm. The biofilm should be removed before application of restorative material, because it may reduce the bond strength of adhesive system. The aim of this study was to evaluate the microtensile bond strength, when the biofilm was removed with brush or bur. Twenty extracted human third molars were sectioned horizontally to obtain dentin surface. Specimen were divided randomly into four group. Biofilm formation was performed in three group, except for Group 1 (negative control). Biofilm was removed as follows: Group 3, using ICB brush; Group 4, using lowspeed round bur #2. Group 2 (positive control) was not removed Biofilm. And in all four groups, the adhesive system (Optibond FL, Kerr) was applied to etched dentin surface, and resin composite was built up in three 1mm increments. After 24 hour storage in distilled water, the teeth were perpendicularly sectioned to obtain beams (1 × 1 mm2). Microtensile bond strength was measured and the data were statistically analyzed using one-way ANOVA and Tukey's post hoc test (p<0.05). Group 4 showed the highest microtensile bond strength (p<0.05), Group 3 showed no significant improvements when compared to Group 1. Group 2 showed lowest microtensile bond strength (p<0.05). When restoring a non-carious cervical lesion, it is essential to remove the biofilm present on the dentin surface. In addition, in the method of removing the biofilm, both the brush removal method and the bur removal method were effective.

• Journal of Institute of Control, Robotics and Systems
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• v.22 no.7
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• pp.496-501
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• 2016

This paper presents a design method of non-parallel distributed compensation (non-PDC) static output feedback controller for continuous- and discrete-time T-S fuzzy systems. The existence condition of static output feedback control law is represented in terms of linear matrix inequalities (LMIs). The proposed sufficient stabilizing condition does not need any transformation matrices and equality constraints and is less conservative than the previous result of [21].

• Restorative Dentistry and Endodontics
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• v.28 no.6
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• pp.498-503
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• 2003

The purpose of this study was to evaluate the rewetting effect of water-based primer on the air-dried dentin. In this in vitro study, freshly extracted non-caries human molars and three-step adhesive system(SBMP) were used. Freshly extracted non-caries human molars and three-step adhesive system(SBMP) were used. Flat occlusal dentin surface were prepared using low-speed diamond saw, Prepared teeth were randomly divided into three groups. Group 1.(W): etched(35% phosphoric acid for 15s) and blot-dried, Group 2.(5D): 5s air-dried, Group 3.(30D): 30s ail-dried, To obtain color contrast in CLSM observation, primer was mixed with rhodamine B and bonding resin was mixed with fluorescein. Microscopic sample of each group were obtained after longitudinal section. Morphological investigation of resin-dentin interface and thickness of hybrid layer measurement using CLSM were done. Microtensile bond strength for each specimen was measured. Specimen were observed under microscope to examine the failure patterns of interface between resin and dentin. The results of this study were as follows: 1. The results(mean) of Thickness of hybrid layer were W:19.67, 5D:20.9, 30D:10$\mu\textrm{m}$. Only 30D had statistically significant differences to Wand 5D(P<0.05). 2. The results(mean) of Microtensile bond strength were W:16.02, 5D:14.69, 30D:11.14MPa. Only 30D had statistically significant differences to Wand 5D(P<0.05). 3. There were positive correlation between Thickness of hybrid layer and microtensile bond strength(P<0.05).

• Restorative Dentistry and Endodontics
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• v.49 no.1
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• pp.4.1-4.9
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• 2024

Objectives: This study aims to correlate caries-causing microorganism load, lactic acid estimation, and blood groups to high caries risk in diabetic and non-diabetic individuals and low caries risk in healthy individuals. Materials and Methods: This study includes 30 participants divided into 3 groups: Group A, High-risk caries diabetic individuals; Group B, High-risk caries non-diabetic individuals; and Group C, Low-risk caries individuals. The medical condition, oral hygiene, and caries risk assessment (American Dental Association classification and International Caries Detection and Assessment System scoring) were documented. Each individual's 3 mL of saliva was analyzed for microbial load and lactic acid as follows: Part I: 2 mL for microbial quantity estimation using nutrient agar and blood agar medium, biochemical investigation, and carbohydrate fermentation tests; Part II: 0.5 mL for lactic acid estimation using spectrophotometric analysis. Among the selected individuals, blood group correlation was assessed. The χ² test, Kruskal-Wallis test, and post hoc analysis were done using Dunn's test (p < 0.05). Results: Group A had the highest microbial load and lactic acid concentration, followed by Groups B and C. The predominant bacteria were Lactobacilli (63.00 ± 15.49) and Streptococcus mutans (76.00 ± 13.90) in saliva. Blood Group B is prevalent in diabetic and non-diabetic high-risk caries patients but statistically insignificant. Conclusions: Diabetic individuals are more susceptible to dental caries due to high microbial loads and increased lactic acid production. These factors also lower the executing tendency of neutrophils, which accelerates microbial accumulation and increases the risk of caries in diabetic individuals.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.3
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• pp.211-217
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• 2011

This paper proposes a quasi-optimal linear DOA (Direction-of-Arrival) estimator which is necessary for the development of a real-time robot auditory system tracking moving acoustic source. It is well known that the use of conventional nonlinear filtering schemes may result in the severe performance degradation of DOA estimation and not be preferable for real-time implementation. These are mainly due to the inherent nonlinearity of the acoustic signal model used for DOA estimation. This motivates us to consider a new uncertain linear acoustic signal model based on the linear prediction relation of a noisy sinusoid. Using the suggested measurement model, it is shown that the resultant DOA estimation problem is cast into the NCRKF (Non-Conservative Robust Kalman Filtering) problem [12]. NCRKF-based DOA estimator provides reliable DOA estimates of a fast moving acoustic source in spite of using the noise-corrupted measurement matrix in the filter recursion and, as well, it is suitable for real-time implementation because of its linear recursive filter structure. The computational efficiency and DOA estimation performance of the proposed method are evaluated through the computer simulations.