• The korean journal of orthodontics
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• v.47 no.3
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• pp.151-157
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• 2017

Objective: The objective of this study was to investigate the differences in masticatory efficiency among patients with different Angle's classes of malocclusion and to assess the correlation between masticatory efficiency and the occlusal contact area. Methods: The mixing ability index (MAI) was calculated for measuring masticatory efficiency of 61 adult patients according to Angle's classifications of malocclusion. The study included 25, 15, and 21 patients with Angle's Class I, II, and III malocclusions, respectively. Silicone interocclusal recording material was used to measure the occlusal contact area. Results: Both the MAI and occlusal contact area showed the highest average values in the Class I malocclusion group, followed by the Class II and Class III malocclusion groups. No significant difference was observed in the MAI values between the Class I and Class II malocclusion groups (p > 0.05), whereas a significant difference was observed between the Class I and Class III malocclusion groups (p < 0.01) and between the Class II and Class III malocclusion groups (p < 0.05). A weak positive correlation was also observed between the MAI and occlusal contact area (p < 0.01, $r^2=0.13$). Conclusions: The results of this study indicated that masticatory efficiency was the highest in patients with Angle's Class I malocclusion, followed by those with Angle's Class II and Angle's Class III malocclusions. Moreover, a weak positive correlation was observed between masticatory efficiency and the occlusal contact area.

• The Pure and Applied Mathematics
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• v.27 no.4
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• pp.171-186
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• 2020

Long back in 1972, it was shown that the sum of the squares of vertex degrees and the sum of cubes of vertex degrees of a molecular graph both have large correlations with total 𝜋-electron energy of the molecule. Later on, the sum of squares of vertex degrees was named as first Zagreb index and became one of the most studied molecular graph parameter in the field of chemical graph theory. Whereas, the other sum remained almost unnoticed until recently except for a few occasions. Thus it got the name "forgotten" index or F-index. This paper investigates extremal graphs with respect to F-index among the class of bicyclic graphs with n vertices and k pendant vertices, 0 ≤ k ≤ n - 4. As consequences, we obtain the bicyclic graphs with largest and smallest F-indices.

• Journal of Periodontal and Implant Science
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• v.29 no.3
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• pp.539-553
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• 1999

The purpose of this 6-months study was to compare the clinical and radiographic outcomes following guided tissue regeneration treating human mandibular Class II furcation defects with a bioabsorbable BioMesh barrier(test treatment) or a nonabsorbable ePTFE barrier(control treatment). Fourteen defects in 14 patients(mean age 44 years) were treated with BioMesh barriers and ten defects in 10 patients(mean age 48 years) with ePTFE barriers. After initial therapy, a GTR procedure was done. Following flap elevation, root planing, and removal of granulation tissue, each device was adjusted to cover the furcation defect. The flaps were repositioned and sutured to complete coverage of the barriers. A second surgical procedure was performed at control sites after 4 to 6 weeks to remove the nonresorbable barrier. Radiographic and clinical examinations(plaque index, gingival index, tooth mobility, gingival margin position, pocket depth, clinical attachment level) were carried out under standardized conditions immediately before and 6 months after surgery. Furthermore, digital subtraction radiography was carried out. All areas healed uneventfully. Surgical treatment resulted in clinically and statistically equivalent changes when comparisons were made between test and control treatments. Changes in plaque index were 0.7 for test and 0.4 for control treatments; changes in gingival index were 0.9 and 0.5. In both group gingival margin position and pocket depth reduction was 1.0mm and 3.0mm; clinical attachment level gain was 1.9mm. There were no changes in tooth mobility and the bone in radiographic evaluation. No significant(p${\leq }$0.05) difference between the two membranes could be detected with regard to plaque index, gingival index, gingival margin position, pocket depth, and clinical attachment level. In conclusion, a bioabsorbable BioMesh membrane is effective in human mandibular Class II furcation defects and a longer period study is needed to fully evaluate the outcomes.

• Communications for Statistical Applications and Methods
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• v.27 no.2
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• pp.163-175
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• 2020

We consider a wide class of general weakly-dependent processes, called ψ-weak dependence, which unify almost all weak dependence structures of interest found in statistics under natural conditions on process parameters, such as mixing, association, Bernoulli shifts, and Markovian sequences. For detecting the tail behavior of the weakly dependent processes, change point tests are developed by means of cumulative sum (CUSUM) statistics with the empirical distribution functions of sample extremes. The null limiting distribution is established as a Brownian bridge. Its proof is based on the ψ-weak dependence structure and the existence of the phantom distribution function of stationary weakly-dependent processes. A Monte-Carlo study is conducted to see the performance of sizes and powers of the CUSUM tests in GARCH(1, 1) models; in addition, real data applications are given with log-returns of financial data such as the Korean stock price index.

• Journal of Korean Institute of Industrial Engineers
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• v.29 no.3
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• pp.222-229
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• 2003

In this paper, we address a layout design problem, PTN[2], for determining an appropriate 2-class-based dedicated storage layout in a class of unit load storage systems. Our strong conjecture is that PTNI2] is NP-hard. Restricting PTN[2], we provide three solvable cases of PTN[2] in which an optimal solution to the solvable cases is one of the partitions based on the PAI(product activity index)-nonincreasing ordering. However, we show with a counterexample that a solution based on the PAI-non increasing ordering does not always give an optimal solution to PTN[2]. Utilizing the derived properties, we construct an effective heuristic algorithm for solving PTN[2] based on a PAI-non increasing ordering with performance ratio bound. Our algorithm with O($n^2$) is effective in the sense that it guarantees a better class-based storage layout than a randomized storage layout in terms of the expected single command travel time.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.5
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• pp.2189-2198
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• 2012

This study was designed to measure the difference in health-related quality of life (HRQOL) among social classes and explore the factors that may explain it. Study subjects were 7,992 Korean adults aged 20-69 from the 4th (2007-2009) Korea National Health and Nutrition Examination Surveys data. We described mean value of EQ-5D index as a HRQOL by class and performed hierarchical multiple regression analysis to find the factors. The result was as follows. In the distribution of EQ-5D index level among social classes, new middle class (class II) had the highest score (0.966 in men and 0.955 in women); upper and middle-upper class (class I) 0.965 in men and 0.936 in women; working class (class IV) 0.958 in men and 0.936 in women; old middle class (class III) 0.955 in men and 0.932 in women; low class (class VI) 0.941 in men and 0.908 in women; and rural self-management class (class V) the lowest score (0.918 in men and 0.866 in women). In men, chronic disease, job stress, education and income level were found to make the difference in the health-related quality of life among social classes; in women, those factors and health behavior explained the difference. In conclusion, the lower social class has lower HRQOL. Except for education and income level, chronic disease may be the major factor to explain the difference in the health-related quality of life among social classes.

• Journal of Korean Institute of Industrial Engineers
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• v.30 no.3
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• pp.190-196
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• 2004

In this paper, we address a layout design problem, PTL[3], for determining an optimal 3-class-based dedicated linear storage layout in a class of unit load storage systems. Our objective is to minimize the expected single command travel time. We analyze PTL[3] to derive a fundamental property that an optimal solution to PTL[3] is one of the partitions based on the PAI(product activity index)-nonincreasing ordering. Using the property and partial enumeration, we construct an efficient exact algorithm with O $(n\;{\lceil}\;log\;n\;{\rceil}\;)$ for solving PTL[3].

• Korean Journal of Community Nutrition
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• v.11 no.2
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• pp.161-171
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• 2006

This study was carried out to investigate the dietary attitudes and nutritional status of preschool children in different income levels in Busan. The survey was conducted from November 1 to November 30, 2004 by questionnaires mid data analyzed by the SPSS program. The results are summarized as follows: The Kaup index of the upper income class group was higher than that of the other income classes. In the middle income class group, nutrition knowledge scores were higher than in any other income class. Sixty-four point nine percent of the upper income class children, 25.7% of the middle income class children and 15.7% of the low income class children had nutrition education experiences. Intake of protein was higher than that of the Korean recommended dietary allowances (RDAs) for children. In the upper income class group, intake of calcium was higher than in any other income class. Intakes of calcium and iron were lower than those of the RDAs in all children. Dietary attitude had positive correlation with frequency of breakfast, time for outdoor activity, and height and weight, and had negative correlation with frequency of fast food and time for watching television. Frequency of snack had positive correlation with frequency of fast food and time for watching television, but frequency of breakfast had negative correlation with those. These results indicate that nutrition education programs linking parents to children should be carried out to improve their nutritional status.

• Imaging Science in Dentistry
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• v.49 no.4
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• pp.281-286
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• 2019

Purpose: The purpose of this study was to evaluate the morphology of the mandibular cortex in cases of medication-related osteonecrosis of the jaw (MRONJ) in patients with osteoporosis or bone metastases using a computer programme. Materials and Methods: Fifty-four patients with MRONJ (35 with osteoporosis and 19 with bone metastases) were examined using panoramic radiography. The morphology of the mandibular cortex was evaluated using a computer programme that scanned the mandibular inferior cortex and automatically assessed the mandibular cortical index (MCI) according to the thickness and roughness of the mandibular cortex, as follows: normal (class 1), mildly to moderately eroded (class 2), or severely eroded (class 3). The MCI classifications of MRONJ patients with osteoporosis or bone metastases were evaluated with the Pearson chi-square test. In these analyses, a 5% significance level was used. Results: The MCI of MRONJ patients with osteoporosis(class 1: 6, class 2: 15, class 3: 14) tended to be higher than that of patients with bone metastases(class 1: 14, class 2: 5, class 3: 0)(P=0.000). Conclusion: The use of a computer programme to assess mandibular cortex morphology may be an effective technique for the objective and quantitative evaluation of the MCI in MRONJ patients with osteoporosis or bone metastases.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.908-910
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• 2003

In this paper the extraction method for the best suitable green vegetation area in urban area, Daegu, Korea, was developed using satellite images (1994, 1999, Landsat TM). For this, the GIS overlay analysis of GVI (Green Vegetation Index), SBI (Soil Brightness index), NWI (None-Such wetness Index) was performed to estimate the best suitable green vegetation area. Also, the statistical documents, algorithm and Tasseled-Cap index were used to recognize the change of land cover such as cultivation area, urban area, and damaged area. Through the result of this study, it is possible to monitor the large sized reclamation of land by drainage or damaged area by forest fires. Moreover, information with the change of green vegetation and the status of cultivation by GVI, but also moisture content by percentage by NWI and surface class by SBI can be obtained.