• The korean journal of orthodontics
• /
• v.18 no.2
• /
• pp.421-433
• /
• 1988

The purpose of this study was to investigate the characteristics of craniofacial morphology in adult with crowded dentition. The craniofacial morphology associated with normal and crowded of mandibular dentition was studied in lateral cephalometric radiograph obtained from 145 subjects grouped 44 males and 40 females in normal group, 33 males and 28 females in crowded group. The conclusions were as follows: Means, standard deviations and facial polygons from measurements were obtained from normal and crowded groups. Palatal plane to SN, occlusal plans to SN, mandibular plane to SN, mandibular plane to palatal plane and gonial angle measurements of crowded group were significantly different from normal group and were larger than normal group. SNA, SNB measurements of crowded group were significantly different from normal group and were smaller than normal group. Significant differences were observed between normal group and crowded groups on the basis of $SN/{\underline{1}}$, PP/1, $MP/{\bar{1}}$, and compared with normal group, upper incisors of crowded group were inclined more labially, whereas lower incisors of crowded group were inclined more lingually. Posterior facial height and ramal height were shorter in males of crowded group than those of normal group. Posterior facial height, mandibular length and posterior cranial base length were shorter in females of crowded group than those of normal group. Anterior facial height was longer in females of crowded group than those of normal group.

• The korean journal of orthodontics
• /
• v.27 no.2
• /
• pp.197-208
• /
• 1997

Class III malocclusion patients can be approached with many different types of treatment methods, and thus, each patient's problems must be accurately evaluated to allow selection of the best possible treatment method. Cephalometric analysis is an essential part of diagnosis and treatment planning of orthodontic patients, and it would certainly be helpful if reliable cephalometric guidelines could be set. The author divided 482 Class III malocclusion patients(253 males and 229 females) into fourgroups according to different types of treatment methods they have received to correct imbalance between upper and lower jaws: 1) orthopedic appliance (face mask & RPE), 2) camouflage treatment with fixed appliance, 3) surgical-orthodontic treatment, 4) cross-bite correction with removable plates/ functional appliance. Cephalometric values at the time of first clinical examination were compare among the four groups. Cephalometric analysis indicates the following results: 1)the amounts of antero-posterior and vertical skeletal discrepancies and dental compensation were greatest in surgery group 2) SNB, Wits, distance from Nasion Perpendicular Plane to point a facial angle, facial convexity, and APDI were greater in orthopedic appliance group than fixed appliance(camouflage) group, but there was no statistical difference 3) removable plates/ functional appliance group showed least amounts of skeletal discrepancies and dental compensation with statistical significance.

• Journal of Internet Computing and Services
• /
• v.21 no.4
• /
• pp.97-107
• /
• 2020

This study aims to conduct a comprehensive meta-study from the perspective of content analysis to explore trends in Korean academic research on the sharing economy by using the big data analytics. Comprehensive meta-analysis methodology can examine the entire set of research results historically and wholly to illuminate the tendency or properties of the overall research trend. Academic research related to the sharing economy first appeared in the year in which Professor Lawrence Lessig introduced the concept of the sharing economy to the world in 2008, but research began in earnest in 2013. In particular, between 2006 and 2008, research improved dramatically. In order to grasp the overall flow of domestic academic research of trends, 8 years of papers from 2013 to the present have been selected as target analysis papers, focusing on titles, keywords, and abstracts using database of electronic journals. Big data analysis was performed in the order of cleaning, analysis, and visualization of the collected data to derive research trends and insights by year and type of literature. We used Python3.7 and Textom analysis tools for data preprocessing, text mining, and metrics frequency analysis for key word extraction, and N-gram chart, centrality and social network analysis and CONCOR clustering visualization based on UCINET6/NetDraw, Textom program, the keywords clustered into 8 groups were used to derive the typologies of each research trend. The outcomes of this study will provide useful theoretical insights and guideline to future studies.

• The Journal of the Korea Contents Association
• /
• v.20 no.6
• /
• pp.482-497
• /
• 2020

The purpose of this study is to find out how college students overseas field trip group's social network exist, how the network change during the travel period, and how they are related to trip satisfaction, school involvement and peer relations. College students have an unprecedented school adaptation problem, which is questioning college education practices and measure should be taken. Since travel provides a strong bond with the group of participants, in a similar vein, students' overseas trips are also assumed to strengthen solidarity of students. For 31 trip participants, survey was administered to find out the existence of a distinctive network structure, its changes, and its impact on related variables. First, the network structure of the field trip existed explicitly, in which student representatives held their position in degree centrality. Second, network structure has changed before and after the trip, which is due to the social interaction between participants. Third, the effect on trip performance variables was marginal, even if some participants move to centrality. Forth, field trip satisfaction, school involvement, and peer relations were significant correlated. At the end of the paper, the implications and limitations of the study were included.

• International Commerce and Information Review
• /
• v.19 no.3
• /
• pp.3-23
• /
• 2017

With the globalization of the world economy, international trade networks are expanding beyond geographical proximity, and the expansion of such trade networks is playing a role in promoting globalization. Korea has established itself as a strong FTA for the past 13 years, starting with the Korea-Chile FTA. Successful establishment of a short-term FTA network has shown positive economic effects such as increased trade volume with partner countries and market share in overseas markets. Other countries are also turning to the paradigm of economic development through the formation of a regional economic integration and a bilateral trade agreement network, and it is time to investigate new opportunities through understanding the entire RTA and FTA network. In this study, we analyzed the status of RTA and FTA from the 1960s to 2010s, analyzed network structure and centrality through SNA(social network analysis). The results of the study show that the structure of the FTA network is gradually expanding, and the FTA network, which has been expanding to the center of the early European countries, is changing toward the Asian countries such as Korea, China and Japan. As a result of the analysis of the degree of centrality, Korea was ranked as the top in all the degree of centrality(Degree, Betweenness, Closeness and Eigenvector) indicators for a short period of time and it means that Korea's FTA strategy was evaluated as very successful. This study examines the FTA among the global RTAs, assesses the structure of the FTAs and evaluates Korea's FTA strategies and the FTA network from a network perspective.

• The korean journal of orthodontics
• /
• v.19 no.1 s.27
• /
• pp.201-218
• /
• 1989

This study was focused on the distribution of different facial types of the Class II division I malocclusion groups and skeletal characteristics of the each group and those that anteropsterior relationship of the maxilla and mandible calculated from the analysis of ANB angle and Wits appraisal was quite different from each other, as well. Cephalometric headplates of 140 persons of Class II division 1 malocclusion whose mean age was 11.2 years and 69 persons of normal occlusion whose mean age was 12.2 years were utilize as materials. Measurements were recorded, tabulated and statistically analyzed employing the tracings of the lateral cephalograms, then Class II division 1 malocclusion group was divided into 9 Types according to the angle of SNA and SNB for the anteroposterior relationship of the maxilla and mandible, another 9 Types according to the FH-NPog and SN-MP for the horisontal and vertical relationship, and the other 9 Types according to the ANB and Wits appraisal for intermaxillary relationship as well, with which was based on $Mean{\pm}$ 1SD of those of normal occlusion. The result allowed the following conclusion: 1. $37.1\%$ of population demonstrated maxilla within nounal range and retrognathic mandible to the cranial base, $30\%$ for both maxilla and mandible within normal range, $20\%$ for retrognathic maxilla and mandible and $12.9\%$ of the rest were ananged in Class II division 1 maloccusion groups. 2. Retrognathic mandible and hyperdivergent face accounted for $30.7\%$, mesognathic mandible and neutrodivergent face for $29.3\%$, mesognathic mandible and hyperdivergent face for $16.4\%$, retrognathic mandible and neutrodivergent face for $13.6\%$, mesognathic mandible and hypodivergent face for $10\%$ of population were computed in Class II division 1 malocclusion groups. 3. It was suggested that skeletal Class II malocclusion might be due to anomaly in size and shape of cranial base, underdevelopment of mandible, retropositioning of mandible, underdevelopment of posterior face against anterior face, or any combination of these factors. 4. Population with underdevelopment and / or retropositioning of the mandible showed hyperdivergent tendency of facia profile. 5. The ANB angle and Wits appraisal did not coincide the severity of anteroposterior dysplasia in $35.7\%$ of Class II division 1 malocclusion group each other, and this inconsistency was suggested to be related with mandibular rotation, inclination of cranial base, and anteroposterior position of the maxilla.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.36 no.6
• /
• pp.502-507
• /
• 2010

Introduction: This study examined the genetic influence of mandibular prognathism epidemiologically in Korean families. Materials and Methods: Over a 5-year period from 2005 to 2009, a questionnaire with a pedigree chart was given to 100 (male 51, female 49) probands with skeletal Class III mandibular prognathism, who had undergone orthognathic surgery in Samsung Medical Center. Results: The average age of the probands was 22.1. The average SNA, SNB and ANB angles of the probands were $81.2^{\circ}$, $84.1^{\circ}$ and $-2.9^{\circ}$, respectively. A total of 2729 (male 1,354, female 1,375) family members were examined, and the affected ratio of the families was 3.5% with no significant difference between genders. 45% of families had at least one member with a Class III malocclusion other than the proband. The affected ratio of the first-degree relatives (10.9%) was significantly higher than those of the second-degree (3.3%) and third-degree (1.9%) relatives. The affected ratio of the total relatives from the male probands (4.2%) was significantly higher than that of the female probands (2.8%). Heritability ($h^2$, Falconer' method) was estimated to be 29.8% ($0.298{\pm}0.059$) in first-degree relatives. Conclusion: These results showed the significant influence of mandibular prognathism with relatively low heritability in first-degree relatives in Korean families of probands, who had undergone orthognathic surgery to correct a skeletal Class III malocclusion.

• The korean journal of orthodontics
• /
• v.28 no.5 s.70
• /
• pp.763-774
• /
• 1998

The purpose of this study was to evaluate the morphology of mandibular symphysis and location of lower incisor under the influence of the craniofacial skeleton in skeletal Class III malocclusion. The sample consisted of 132 adults who have severe Class III malocclusion(prognathism group, 33 males and 33 females), and who have normal occlusion(normal group, 33 males and 33 females). They had not received any orthodontic treatment or orthognathic surgery. The lateral cephalograms were evaluated. The results were as follows : 1. Prognathism group were larger than normal group in comparison of facial skeleton (p<0.05) with the exception of ${\angle}FH-Pal$, ${\angle}SNA$. 2. In the morphology of symphysis, measurements of anteroposterior width(LaABBW, LiABBW, SW) of prognathism group were significantly less than that of normal group(p<0.001). 3. In the correlative analysis between the craniofacial skeleton and symphysis measurements of prognathism group, vertical measurements in relation with cranial base and mandibular plane showed reverse correlationship with anteroposterior width of symphysis(LiACBW, LaACBW, LiABBW, SW)(p<0.05). But, there was not distinct difference between horizontal skeletal measurements and symphysis measurements(p>0.05). 4. The probability by regression test between vertical measurements(${\angle}SN-Mn,\;{\angle}FMA,\;{\angle}Pal-Mn,\;{\angle}LFH$) and symphysis measurements(LiACBW, LiABBW, SW, ${\angle}LISA$) were very high(p<0.001).

• The korean journal of orthodontics
• /
• v.40 no.4
• /
• pp.227-238
• /
• 2010

Objective: The purpose of this study was to analyze the effect of growth hormone treatment (GHT) on craniofacial growth in children of short stature. Methods: Nineteen untreated children of short stature were referred from the Pediatric Department, Yeungnam University Hospital as a subject group. All subjects had lateral cephalograms taken before, after 1 year and after 2 years of growth hormone treatment. As a reference group, we selected 19 normal children with paired sampling who matched the subjects' age and sex, from the Department of Orthodontics, Kyungpook National University Hospital. Results: Before GHT, anterior cranial base length and upper posterior facial height, posterior total facial height, mandibular ramus length, and mandibular corpus length were significantly smaller in the reference group. In angular craniofacial measurements, saddle angle and mandibular plane angle were larger. SNA and SNB were smaller in the reference group. After two years of GHT, growth hormone accelerated growth in several craniofacial components. The posterior total facial height, the anterior, posterior cranial base length, and the mandibular ramus length were increased. And the difference in mandibular plane angle and ANB values compared with the reference group was decreased. Conclusions: GHT over 2 years leads to a craniofacial catch-up growth tendency, which is pronounced in interstitial cartilage and condylar cartilage.

• Journal of Navigation and Port Research
• /
• v.39 no.3
• /
• pp.217-222
• /
• 2015

In this research, sea routes of domestic coaster liners between 2005 and 2013 were studied via social network analysis. Study of the sea routes revealed that they follow power-law in a scale-free form, a characteristic found often in social network. We have looked into centrality, which is a major standard in the field of social network analysis. We have also analyzed the annual changing trend in the centrality of the connectivity, examined the effect of quantity through the comparison with the original quantitative analysis method, and lastly, verified the relationship between the centrality of connectivity and mediation. Then, we were able to identify ports according to priority using these factors. This research assumed and interpreted the coaster liners route as a single network and suggested useful results. Based on these results, directing of development of domestic coaster liners route development and other factors will be achieved more smoothly. And if we utilize social network analysis method in other various fields - for example, the centrality of airport and the diplomatic realations analysis of the neighboring country - we will be able to effectively analyze events in diverse perspectives.