• Journal of the Korean Mathematical Society
• /
• v.51 no.5
• /
• pp.1089-1104
• /
• 2014

An operator $T{\in}L(H)$, is said to belong to k-quasi class $A_n^*$ operator if $$T^{*k}({\mid}T^{n+1}{\mid}^{\frac{2}{n+1}}-{\mid}T^*{\mid}^2)T^k{\geq}O$$ for some positive integer n and some positive integer k. First, we will see some properties of this class of operators and prove Weyl's theorem for algebraically k-quasi class $A_n^*$. Second, we consider the tensor product for k-quasi class $A_n^*$, giving a necessary and sufficient condition for $T{\otimes}S$ to be a k-quasi class $A_n^*$, when T and S are both non-zero operators. Then, the existence of a nontrivial hyperinvariant subspace of k-quasi class $A_n^*$ operator will be shown, and it will also be shown that if X is a Hilbert-Schmidt operator, A and $(B^*)^{-1}$ are k-quasi class $A_n^*$ operators such that AX = XB, then $A^*X=XB^*$. Finally, we will prove the spectrum continuity of this class of operators.

• The korean journal of orthodontics
• /
• v.17 no.1
• /
• pp.63-72
• /
• 1987

This is to investigate the difference between craniofacial correlation of Angle's class III malocclusion and that of normal occlusion. For this investigation, 28 adult males and famales, who have class III malocclusion, and 35 adult males and 46 adult famals., who have normal occlusion were selected to measure actual dimension of cranial base and to investigate ratio of various parts of maxillofacial skeleton against cranial base. Class III malocclusion were, also , classified based on SNA and SNB angle in normal range. Results were as follows. 1. In class III malocclusion, actual dimension of cranial base were appeared to be less than normal occlusion in both sex. 2. In class III malocclusion, values were less than normal occlusion in BN/ptm-A in both sex, but had no significance between two. 3. In class III malocclusion, ramal inclination, mandible inclination, BN/Go-Pog, lower genial angle were appeared to be greater. Thus, characteristic mandibular protrusive appearance of class III malocclusion was due to relative ratio and morphologic characteristic of mandibular body dimension against cranial base. 4. In class III malocclusion, upper incisors were labially tilted and lower incisors were lingually tilted compared to normal occlusion. 5. In typing of class III malocclusion, the most common type was found to be one which maxillas were in normal range, while mandibles were in protrusive tendency.

• The korean journal of orthodontics
• /
• v.41 no.2
• /
• pp.127-137
• /
• 2011

Objective: The aim of the study was to compare the opening and protrusive mandibular movements between Class I and Class II malocclusions in healthy adolescents by clinical and axiographic evaluations. Methods: Mechanical axiography was performed on non-orthodontically treated, temporomandibular disorder (TMD)-free adolescents (12 - 16 years) with Class I (n = 38, 16 boys, 22 girls) or Class II (n = 40, 19 boys, 21 girls) malocclusion. Opening and protrusive movements were measured clinically and axiographically. Intergroup comparisons were evaluated by t-tests. Results: In opening movement, the maximum clinical opening capacity was significantly different (p ${\leq}$ 0.05) between the groups. In protrusive movement, the Class II group had significantly greater maximum clinical protrusion (p < 0.001) and maximum axiographic protrusive length (p < 0.01) than the Class I group. No significant difference in the other opening and protrusive axiographic measurements was observed. Conclusions: TMD-free adolescents with Class II malocclusion have increased protrusive capacity compared with TMD-free adolescents with Class I malocclusion; however, the detected differences could be normal variations during adolescence.

• Journal of Fisheries and Marine Sciences Education
• /
• v.29 no.1
• /
• pp.209-223
• /
• 2017

The purpose of this study is to compare and analyze science self-efficacy, science self-concept and scientific attitude according to the class size in the elementary school. For this purpose, three research questions were set as follows; First, are there any differences in science self-efficacy according to the class size? Second, are there any differences in science self-concept according to the class size? Third, are there any differences scientific attitude according to the class size? To solve this research questions, the subjects in this study were 809 5th and 6th grade students of eight elementary schools in Busan. 220 were sampled from small-size classes, 354 from mid-size classes and 235 from large-size classes. The results of this study through the process are as follows; First, there were significant differences in science self-efficacy according to the class size. Second, there were significant differences in science self-concept according to the class size. Third, according to the result, there was not a significant difference in scientific attitude according to the class size. The findings of the study suggest that it is necessary the class size should be adjusted to the appropriate level for improving student's science self-efficacy and science self-concept.

• Journal of Korean Neurosurgical Society
• /
• v.44 no.1
• /
• pp.19-25
• /
• 2008

Objective : To analyze the relationship of concomitant foraminallumbar disc herniation (FLDH) with postoperative leg pain after microdecompression for extraforaminallumbar disc herniation (EFLDH) at the L5-S1 level. Methods : Sixty-five patients who underwent microdecompression for symptomatic EFLDH at the L5-S1 level were enrolled, According to the severity of accompanying FLDH, EFLDH was classified into four categories (Class I : no FLDH; Class II : mild to moderate FLDH confined within a lateral foraminal zone; Class III : severe FLDH extending to a medial foraminal zone; Class IV : Class III with intracanalicular disc herniation). The incidence of postoperative leg pain, dysesthesia, analgesic medication, epidural block, and requirement for revision surgery due to leg pain were evaluated and compared at three months after initial surgery. Results : The incidences of postoperative leg pain and dysesthesia were 36.9% and 26.1%, respectively. Pain medication and epidural block was performed on 40% and 41.5%, respectively, Revision surgery was recommended in six patients (9.2%) due to persistent leg pain, The incidences of leg pain, dysesthesia, and requirement for epidural block were higher in Class III/IV, compared with Class I/II. The incidence of requirement for analgesic medication was significantly higher in Class III/IV, compared with Class I/II (p=0,02, odds ratio=9,82). All patients who required revision surgery due to persistent leg pain were included in Class III/IV. Conclusion : Concomitant FLDH seems related to postoperative residual leg pain after microdecompression for EFLDH at the L5-S1 level.

• Journal of the Korean Society of Earth Science Education
• /
• v.9 no.1
• /
• pp.54-64
• /
• 2016

The purpose of this study was to see the influences of science class applying learning cycle emphasized exploration on science learning motivation and scientific attitude of elementary students. The results drawn from this analysis were as below. Firstly, positive relationship was found between science learning motivation and science class applying learning cycle emphasized exploration among the research group. This shows that science learning motivation was improved by science class applying learning cycle emphasized exploration. It indicates that science class applying learning cycle emphasized exploration is effective in improving science learning motivations. Secondly, positive relationship was found between scientific attitude and science class applying learning cycle emphasized exploration among the research group and this means that science class applying learning cycle that emphasizes exploration stimulates intellectual curiosity of elementary school students and improves their scientific attitude. Thirdly, students thought that science class applying learning cycle emphasized exploration was very effective to improve their satisfaction, interest, participation in their science classes. Above results show that science class applying learning cycle emphasized exploration is highly effective for elementary students. Thus, it is needed to utilize science class applying learning cycle emphasized exploration to current science class as it can promote wider scientific activities among elementary school students.

• Journal of the Korea Fashion and Costume Design Association
• /
• v.17 no.1
• /
• pp.13-24
• /
• 2015

The purpose of this study is to examine the influences of learners' self-efficacy on class satisfaction in learning practical basic sewing. Questionnaires were distributed to 181 college women students living in the areas of Deagu Metropolitan City and Gyeongbuk Province. The data obtained were analyzed by using various statistical tools: frequency, factor analysis, reliability analysis, correlation analysis, and multiple regression. The self efficacy of learners of practical basic sewing were made up of five factors: ability to manage interpersonal relationships, ability to deal with assigned tasks, anxiety, challenging spirit, and fear. Class satisfaction was composed of the following factors such as interest in class, professors' ability, achievement of class objectives, connectivity, preparation for class, preference for practices, and perfectibility. This study indicated the correlations between sub-variables of learners' self efficacy and class satisfaction. In other words, the higher were the levels of ability to manage interpersonal relationships, and ability to deal with assigned tasks in self efficacy, the higher were the levels of interest in class, professors' ability, achievement of class objectives, preference for practices, and perfectibility in class satisfaction. The factors of ability to deal with assigned tasks, anxiety, and challenging spirit, in learners' self efficacy were found to have statistically significant effects on the achievement of class objectives. The factor of ability to deal with assigned tasks in self efficacy had a statistically significant influence on professors' ability. The factors of ability to deal with assigned tasks, anxiety, challenging spirit and fear were found to have statistically significant effects on all the factors of class satisfaction.

• The korean journal of orthodontics
• /
• v.48 no.6
• /
• pp.349-356
• /
• 2018

Objective: This study was performed to investigate the alveolar bone of lower incisors in skeletal Class III adults of different vertical facial patterns and to compare it with that of Class I adults using cone-beam computed tomography (CBCT) images. Methods: CBCT images of 90 skeletal Class III and 29 Class I patients were evaluated. Class III subjects were divided by mandibular plane angle: high (SN-MP > $38.0^{\circ}$), normal ($30.0^{\circ}$ < SN-MP < $37.0^{\circ}$), and low (SN-MP < $28.0^{\circ}$) groups. Buccolingual alveolar bone thickness was measured using CBCT images of mandibular incisors at alveolar crest and 3, 6, and 9 mm apical levels. Linear mixed model, Bonferroni post-hoc test, and Pearson correlation analysis were used for statistical significance. Results: Buccolingual alveolar bone in Class III high, normal and low angle subjects was not significantly different at alveolar crest and 3 mm apical level while lingual bone was thicker at 6 and 9 mm apical levels than on buccal side. Class III high angle group had thinner alveolar bone at all levels except at buccal alveolar crest and 9 mm apical level on lingual side compared to the Class I group. Class III high angle group showed thinner alveolar bone than the Class III normal or low angle groups in most regions. Mandibular plane angle showed negative correlations with mandibular anterior alveolar bone thickness. Conclusions: Skeletal Class III subjects with high mandibular plane angles showed thinner mandibular alveolar bone in most areas compared to normal or low angle subjects. Mandibular plane angle was negatively correlated with buccolingual alveolar bone thickness.

• The korean journal of orthodontics
• /
• v.10 no.1
• /
• pp.45-53
• /
• 1980

This study was based on the study models of 32 subjects with normal occlusion, 40 with Class I malocclusion, 32 with Class II, Division 1 malocclusion and 38 with Class III malocclusion, aged 12 to 20 years (mean age 16.4 years). The purpose of present study was to define the difference between normal and malocclusion groups in maxillary dental arch and palate. On the basis of findings of this study, the following results were obtained. 1. The intermolar widths and the intercanine widths in Class II, Div. 1 malocclusion group were smaller than in normal occlusion group significantly. 2. The arch lengths measured in both Class I and Class II, Div.1 malocclusion groups were larger than in normal occlusion group. 3. The palates in Class I and Class II, Div. 1 malocclusion groups were longer and narrower than in normal occlusion, but the palates in Class III malocclusion group were shorter than in normal occlusion group significantly. 4. The palatal depths measured at level 1 in Class III malocclusion group were significantly higher than in normal occlusion and in Class II, Div. 1 group they were significantly higher than in normal occlusion at level 2 and 3. 5. The measurements of palatal areas at various levels showed no significant difference between malocclusion and normal occlusion groups. 6. The palatal indies 1 (palatal length / palatal width) measured in both Class I and Class II, Div. 1 malocclusion groups were significantly greater than in normal occlusion and the palatal indice 2 (palatal depth at level 1/palatal width) measured in all malocclusion groups are greater than in normal occlusion. 7. It was determined from findings of this study that the measurements of maxillary dental arch and palate were influenced to a considerable extent by the molar relationship.

• The korean journal of orthodontics
• /
• v.43 no.3
• /
• pp.134-140
• /
• 2013

Objective: To evaluate lower incisor position and bony support between patients with Class II average- and high-angle malocclusions and compare with the patients presenting Class I malocclusions. Methods: CBCT records of 79 patients were divided into 2 groups according to sagittal jaw relationships: Class I and II. Each group was further divided into average- and high-angle subgroups. Six angular and 6 linear measurements were performed. Independent samples t-test, Kruskal-Wallis, and Dunn post-hoc tests were performed for statistical comparisons. Results: Labial alveolar bone thickness was significantly higher in Class I group compared to Class II group (p = 0.003). Lingual alveolar bone angle (p = 0.004), lower incisor protrusion (p = 0.007) and proclination (p = 0.046) were greatest in Class II average-angle patients. Spongious bone was thinner (p = 0.016) and root apex was closer to the labial cortex in high-angle subgroups when compared to the Class II average-angle subgroup (p = 0.004). Conclusions: Mandibular anterior bony support and lower incisor position were different between average- and high-angle Class II patients. Clinicians should be aware that the range of lower incisor movement in high-angle Class II patients is limited compared to average- angle Class II patients.