• Clinical and Experimental Pediatrics
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• v.48 no.7
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• pp.685-690
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• 2005

Recently, twinning rate increases in Korea since the early 1990s by delayed marriage and prevailing of assisted reproductive technology. But twin and higher-order multiples are at increased risk for perinatal and neonatal mortality over 5 fold despite of dramatic improvement of perinatal and neonatal care. Because twins are born more prematurely and have lower birth weights than singleton. In addition, twins are at increased risk for cerebral palsy mainly in monochorionic twins due to co-twin fetal death, twin to twin transfusion and congenital anomaly. So, this article reviews the factors contributing to the mortality and morbidity of the twins and the efforts to decrease the neonatal mortality of twins.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.4 no.1
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• pp.21-30
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• 1974

A study was performed to investigate the degree of similarities and differences in components of craniofacial complex between Korean twins and normal children by lateral cephalometric analysis. Dimensions of S-N, S-Ba, N-Ba, Go-Me, Ar-Go and Ar-Me were against linear measurement and angles of N-S-Ba and gonial against measurement in twins and control groups. The lateral cephalograms of twin were composed of 88 twins aged from 7 to 12:44 males aged 10.65 and 44 females aged 9.55, while those of 50 normalities were composed of 25 males and 25 females aged 10.9 respectively. In order to analyze growth proportion and sexual differences, twins were divided into 3 groups according to two year age intervals and the author compared male with female in 3 groups. For the purpose of observing similarities and differences in twins and normalities by sex, total twins were compared with normalities. The obtained results were as follows: 1. There was no difference in craniofacial complex between plotted angular normalities. 2. In general, the measurements of male were larger than both twins and normalities, but there were no statistical sexual differences in both groups. 3. The growth proportion of mandible by aging was larger than that of face twins and those of female significances of in twins. 4. The growth pattern of gonial angle showed slightly reducing tendency in twins by aging. 5. There was little difference in the growth proportion of both male and female.

• The Journal of the Korean dental association
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• v.9 no.1
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• pp.43-48
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• 1971

The purpose of this study is to evaluate the influence of genetics of the dimensions of dental arches in twins. Thirty-four pairs of Korean twins, of which twenty-three were monozygotic and eleven dizygotic, participated in the study. The twins ranged in age from 6 years to 12 years with mixed dentition. The results were as follows: 1) No significant differences were observed between male and female in mean interpair diffenences of monozygotic twins. 2) Mean interpair differences of monozygotic twins were lesser than these of dizygotic twins. 3) Highly significiant zygotic differences were observed in the mean interpair differences of the width of upper and lower dental arch. This suggest that there is a significant component of hereditary variability.

• Electronics and Telecommunications Trends
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• v.36 no.1
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• pp.99-108
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• 2021

Digital twins are digital replicas of objects and systems in the real world. These digital replicas in a virtual environment can be connected with smart sensors and a variety of analyses, and simulations of real-time data from these sensors enable effective the operation, rapid feedback, and future predictions of real world phenomena. Until now, digital twins have been adopted and used mainly in the field of manufacturing, especially for smart factories. As digital twins are expected to be useful not only for productivity improvement but also for social problem solving, it is predicted that they will be extended to other fields such as those of transportation and cities. Digital twins will especially help realize smart cities through real-time monitoring, operation, and predictions using virtual digital twin cities. This paper summarizes the trends in digital twins for smart cities, the concept of digital twins, their application to smart cities, the strategies of various countries, and the development status of companies.

• International Journal of Advanced Culture Technology
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• v.10 no.3
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• pp.397-403
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• 2022

The world is paying a lot of attention to digital twins to preoccupy future technological competitiveness. Digital twins can be used in various fields such as manufacturing, medical care, and cities. Various market research institutes predict that the market size of digital twins will gradually expand. Korea has also selected digital twin as one of the representative tasks of the Korean version of the New Deal and is promoting related policies. However, a common platform or standard for building digital twins is not enough. Interoperability is a very important characteristic for the purpose of creating new value through interconnection between digital twins rather than independently developing and utilizing digital twins. The Digital Twin Consortium is an international council for the effective development and utilization of digital twins, and is working to solve the problem of digital twin interoperability. The Digital Twin Consortium recently published the 'Digital Twin System Interoperability Framework', and this paper analyzes the digital twin interoperability based on it.

• The Journal of the Korean dental association
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• v.13 no.4
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• pp.335-337
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• 1975

The auther observed the oral status of the 14 twins clinically, the obtainde results were as follow : 1. In each twins, the color of the teeth, the form of the uper central incisors, the periodontal conditions and the oral hygiene status were resemble each other. 2. In one twin, the dentition and the size of the palatine tonsil were different each other. 3. In two twins, the occlusion and the number of the dental caries were different each other. 4. In four twins, the eruptions of teeth were different each other.

• Journal of Korean Academy of Nursing
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• v.1 no.1
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• pp.103-110
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• 1970

It is important to point out that the percental mortality rate of the multiple pregnancy is almost twice of the single pregnancy due mainly to their prematurity and the mothers of twins will also be suffered from the plural births to nurse and take care of them. We therefore studied the incidence, the sex ratio, the types of deliveries, the complications and the percental mortality rate of the twin deliveries in order to promote the development of our field of maternal and child nursing. We selected our materials from the 112 patients who had been admitted and delivered twins in the department of OB. & Gyn. of the S.N.U. Hospital from Jan. 1962 to Dec. 1969. The abstructed results of this study were as follows. 1. The incidence of twins among 7, 731 births was 1:69 2. The occurrence of twins from elder multigravida was 4 to 6 times higher than younger primigravida mothers under 35 years of age. 3. The generational length of 45.5% of all twins was under 38 weeks and the mean birth weight of 1st and 2nd twins were 2, 354.7gm and 2, 215.8gm respectively. 4. The sex ratio of twins was 99 males and 124 females. 5. Presentation of twins: 59 cases (52.69%) were in both vertex. 37 cases (33.03%) in vertex plus breech. 15 cases (13.39%) in both breech and one case (0.89%) in transverse presentation. 6. For the types of deliveries Spontaneous deliveries were in 90 babies (40.6%) Breech extraction in 60 babies (26.3%) Vacuum used in 33 babies (15.0%) Cesarean section in 33 babies (9.8%) Forceps in 9 babies (4.2%) and others such as version and destructive measures in 9 babies (4.1%) 7. Intervals between the 1st and 2nd delivery were analyzed and 93% of 2nd twins were delivered within minutes after 1st delivery. 8. The main complications of twin deliveries were totemic (45.5%), second was postmarital hemorrhage (19.6%) and third was hydrations (7.1%) 9. The mean percental mortality of 1st and 2nd twins was 12.52% and 16.96% respectively of which main cause of death were their prematurity.

• Advances in pediatric surgery
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• v.3 no.2
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• pp.164-167
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• 1997

Conjoined twins are one of the rarest and most challenging congenital anomalies in pediatric surgery. Successful surgical separation is difficult because it the majority of conjoined twins in is technically typical to separate shared vital organs successfully. The timing of separation is variable, but separation is usually delayed until such infants are relatively mature(i.e, 9-12 months of age). Operative survival was 50 % in the neonatal period, but 90 % in those over 4 months of age. The present case was successfully separated early beacase of cardiac problems in one of the twins. These twins were omphalopagus and only the liver was shared through a bridge. The vascular and biliary trees were independent from each other. Successful surgical separation was on 11th day of life, but one died of sepsis 18 days after operation.

• Archives of Plastic Surgery
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• v.48 no.4
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• pp.378-383
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• 2021

Conjoined twins are rare, and each set of conjoined twins has a unique conjoined anatomy. It is necessary to perform separation to increase the chance of patient survival. Tissue expansion is an advanced technique for providing sufficient soft tissue and skin for wound closure. We report the successful application of rapid tissue expansion in 10-month-old xipho-omphalopagus conjoined twins in Vietnam. A tissue expander was placed on the anterior body between the sternum and umbilicus with a baseline of 70 mL sterile saline (0.9% NaCl). The first injection into the tissue expander began on the 6th day after expander insertion, and injections continued every 2 days with approximately 30-70 mL per injection according to the expansion of the skin. The expander reached 335 mL after six injections and within 10 days. In order to prepare for surgical separation, expansion was completed on the 15th day after insertion. The expanded skin area was estimated to be 180 cm², which was sufficient to cover both patients' skin deficiencies. The twins presented for surgical separation 6 days following the completion of tissue expansion. Both babies were discharged in good health 1 month after separation.

• Advances in pediatric surgery
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• v.9 no.2
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• pp.117-120
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• 2003

Anal canal duplications occurring in a pair of 4 month-old healthy female twins are presented. The openings were located in the posterior midline of the anus since birth without a history of perianal abscess or swelling. Excision of the duplicated anal canals was performed using posterior sagittal approach. Although the anal canal duplication occurs predominantly in female, to our knowledge, this is the first case of anal duplication in a monozygotic female twins reported.