• Journal of KIISE:Information Networking
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• v.37 no.6
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• pp.483-488
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• 2010

Due to the prevalence of various mobile devices and wireless broadband networks, there has been a significant increase in interest and demand for multimedia streaming services. Moreover, the user can service the participatory video broadcasting service in the mobile device and it can be used to deliver the real-time news and more variety information in the user side. Live multimedia service of user participation should consider not only the video quality but also the delay bounds and continuity of video playback for improving the user perceived QoS (Quality of Service) of streaming service. In this paper, we propose an adaptive rate control scheme, called DeBuG (Delay Bounds Guaranteed), to guarantee the delay bounds and continuity of video playback for the real-time streaming in mobile devices. In order to provide those, the proposed scheme has a quality adaptation function based on the transmission buffer status and network status awareness. It also has a selective frame dropper, which is based on the media priority, before the transmission video frames. The simulation results demonstrate the effectiveness of our proposed scheme.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.9
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• pp.190-198
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• 2020

The purpose of this study was to investigate the changing trajectory of self-esteem and to explore contemporaneous and lagged effects of social supports(family, friends, and teacher) of 4th graders in elementary school to 9th graders in middle school. The subjects were 1,296 multiethnic students, who participated in the Multicultural Children and Adolescents Panel Study(MCAPS) from 2011 to 2016. The results of piecewise growth function showed that students' self-esteem was increased during upper grade in elementary school but soon deceased during middle school. Individual differences were found at initial, 1st and 2nd changing status. Students with higher level at initial status in self-esteem showed less increased pattern during elementary school but greater decreased pattern during middle school. In addition, supports from family and teacher showed contemporaneous effects across all 6 years while supports from friends showed such effects only for 5 years except 9th grade. Lagged effects of family were found in elementary school and significant lagged effects with supports from friends were found at 6th and 8th grade. The results of this study imply that the social support of family, friends, and teacher has an important role to encourage the self-esteem of multicultural adolescents.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.10 no.1
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• pp.43-49
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• 1999

Objectives：One of the most common developmental problems is communication disorder in which a child appears normal in every way but who has failed to begin speaking or speaks very little. A few studies have examined the temperamental characteristics of children with communication disorders. This study was to investigate the temperamental characteristics of Korean children with communication disorders. Methods：The parents of 20 Korean children with communication disorders and the parents of 50 normal control children, the age of both groups ranges from 3 to 7, completed Korean version of Parental Temperamental Questionnaire developed by Thomas and Chess. Children with a pervasive developmental disorder, mental retardation, or speech-motor or sensory deficit were excluded. The scores of each temperamental scale of two groups and the diagnostic clusters of two groups were compared. Results：The children with communication disorders were characterized by lower mood scores and higher intensity of reaction scores than normal controls. The two groups showed no significant correlation in terms of the temperamental diagnostic clusters. Conclusion：This findings suggest the existence of a distinct temperamental profile of the children with communication disorders. Early detection of the profile may be of great value for parents in understanding the developmental characteristics of the children with communication disorders and in providing appropriate parenting approaches.

• Journal of the korean academy of Pediatric Dentistry
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• v.44 no.1
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• pp.56-63
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• 2017

Delayed eruption of the first molar, without a generalized or localized cause, is usually associated with delayed development of the affected tooth. The aim of this study was to investigate the clinical features of the first permanent molar showing delayed development and eruption, and its association with developmental anomalies of other teeth. Panoramic radiographs of 40 healthy children showing delayed development and eruption of first permanent molars were analyzed. The clinical features of affected first molars and developmental anomalies of other teeth (except third molars) were evaluated. Delayed first molars were more frequent in the maxilla. The incidence of bilateral delayed development of first molars was greater than that of unilateral cases in female patients. In contrast, male patients showed unilateral delayed development of the first molar more frequently. A higher incidence of congenitally missing teeth was observed in patients with delayed first molar. In each case, delayed development or congenital absence was observed in the second molar adjacent to the delayed first molar. Overall, delayed first molar seems to be associated with congenital absence of additional teeth. Understanding the developmental mechanisms of this phenomenon requires further studies.

• Journal of the korean academy of Pediatric Dentistry
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• v.49 no.1
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• pp.95-103
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• 2022

The first permanent molars play a key role in maxillofacial development and occlusion. The purpose of this study is to investigate the characteristics and development stages of first molars with delayed eruption, and to evaluate their associations with congenital missing teeth. Eight-year-old patients who had delayed eruption in their first molars were classified into 75 patients with physical barriers and 77 patients without physical barriers. The development stages of the first and second molars in the delayed area were analyzed using Nolla method from the panoramic radiographs. The relationship between congenital missing teeth and delayed area was also investigated. Delayed eruption of first molars were more common in the maxilla alone. With the presence of physical barriers, male patients showed higher frequency in unilateral cases, while female patients had higher bilateral cases when there was no physical barrier. Delayed development of first molars were observed in delayed eruption area. In the absence of physical barriers, adjacent second molars were also developed slowly and the incidence of congenital missing teeth was high in delayed area. If first molars with delayed eruption are observed, clinical and radiographical follow-ups are necessary for the evaluation of their developmental stages and congenital missing teeth.

• Korean Journal of Psychosomatic Medicine
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• v.24 no.2
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• pp.165-173
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• 2016

Objectives : Since the awareness of autism spectrum disorders(ASD) is growing, as a result, it is increasing numbers of infants and toddlers being referred to specialized clinics for a differential diagnosis and the importance of early autism spectrum disorders detection is emphasized. This study is to know the difference between ASD and intellectual disability(ID) from comparison of the demographics, clinical characters and obstetric complications. Methods : The participants are 816 toddlers who visited the developmental delay clinic(DDC) in National Health Insurance Ilsan hospital. The number of toddlers diagnosed as ASD and ID was 324 and 492. 75 toddlers out of 114 who returned to DDC were diagnosed as ID at the first visit but 7 of them had changed diagnosis to ASD at the second visit. After compared ASD with ID from the first visit, we analyzed characters of toddlers who had the changed diagnosis to ASD at the second visit. Results : As a result, the comparison between ASD and ID at the first visit shows that the boys have higher ratio, lower obstetric complication and lower language assessment score in ASD. The toddlers who had the changed diagnosis at the second visit were all boys and they had more cases of family history of developmental delay and had lower score of receptive language developmental quotient. Conclusions : These findings suggest that sex, language characteristics and obstetric complication could be useful in the early detection of ASD.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2005.11a
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• pp.331-334
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• 2005

현재 무선 이동통신의 발달로 고속 신뢰성 높은 데이터 전송을 요구하고 있다. 그러나 무선 이동통신 환경은 데이터 전송 시 지연과 간섭 등에 의해 주파수 선택성 페이딩을 가진다. OFDM은 주파수 선택성 페이딩에 영향을 받는 통신 시스템에서 채용되는 강력한 기술이다. OFDM에 적응 변조와 함께 송수신기에 다중의 안테나를 설치함으로서 채널 지연 확산에 강력히 대응한다. 본 논문의 연구는 MIMO 시스템에 적용된 적응 변조를 가진 OFDM이다. OFDM 각 서브채널의 상태에 따라 최적의 비트값을 할당하고 전력을 제어한다. 본 논문에서 제안한 적응비트로딩 MIMO-OFDM 시스템을 사용하면 현재의 시스템보다 더 좋은 BER을 가지며 고속 통신할 수 있다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2018.06a
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• pp.128-129
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• 2018

최근 정보통신 기술의 발달로 사용자에게 원격 공간의 실재감을 느낄 수 있게 하는 실감미디어의 발전이 두드러지고 있다. 이 중 360VR의 경우, 시청자의 시청 영역이 넓어지기 때문에 높은 전송률과 넓은 대역폭을 요구하여 전송 지연과 영상 끊김 등의 여러 문제점이 나타나고 있는 상황이다. 이에 본 논문은 360VR 영상을 지연이 발생하지 않고 전송하기 위해 구글에서 제작한 Chromium 프로젝트의 소스코드를 이용하여 QUIC 서버를 제작하였고 QUIC 프로토콜과 HTTP/2을 이용하여 Chromium 브라우저 클라이언트에 송출하였다. 또한 기존 Node.js 서버의 HTTP 1.1와 비교를 통해 QUIC 프로토콜을 이용한 360VR 전송 속도가 빠르다는 것을 확인하였다.

• Clinical and Experimental Pediatrics
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• v.52 no.2
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• pp.242-246
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• 2009

The clinical features of ring chromosome 13 include mental and growth retardation, CNS anomalies, facial dysmorphism, cardiac defects, genital malformations, limb anomalies, skeletal deformities and anal malformations. Although many cases of ring chromosome 13 have been reported worldwide, only 6 cases have been reported in Korea, and the latter cases were not mosaic but pure ring chromosome 13. Here we report a case with mosaic ring chromosome 13. The baby boy was born at 37 weeks of gestation by induced vaginal delivery due to intrauterine growth restriction (IUGR). He was the second baby of a 28-year-old hepatitis B carrier mother and a 32-year-old father. There was no family history of chromosomal anomalies. The baby was a symmetric IUGR with a birth weight of 1,860 g, length of 44.8 cm, and head circumference of 29.4 cm. The physical examination revealed microcephaly, trigonocephaly, flat occiput, large ears, short neck and dysmorphic facial features, including microophthalmia, hypertelorism, antimongoloid slanting palpebral fissures, a flat nasal bridge, and micrognathia. The karyotype of this patient performed by peripheral blood lymphocytes was 46,XY,r(13)(p13q34)/45,XY,-13/46,XY,dic r(13;13)(p13q34;p13q34). The baby showed failure to thrive, hypotonia, and developmental delay. We report the first case of mosaic ring chromosome 13 in a male baby in Korea and compare this case with other Korean cases of non-mosaic ring chromosome 13.

• Clinical and Experimental Pediatrics
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• v.51 no.5
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• pp.546-550
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• 2008

In this untreated classic phenylketonuria (PKU) case, mental retardation is severe; however, there have been individuals- like the mother of this case- who have escaped mental retardation and all the other potential sequelae of phenylketonuria, despite having high blood phenylalanine levels, and very poor dietary control. It appears that they have nearly normal brain phenylalanine levels despite high blood phenylalanine (Phe) levels. A number of studies have now demonstrated considerable variability in blood vs. brain phenylalanine levels in phenylketonuria patients. Outcome of phenylketonuria appears to be related to brain phenylalanine levels. We report a case of "undiagnosed" maternal phenylketonuria syndrome. A female infant had low birth weight (2,400 g) with microcephaly. We examined her family and discovered that her mother was an undiagnosed phenylketonuria patient with a borderline intelligence quotient (IQ). The infant's sister, six years old, was diagnosed with phenylketonuria at the age of four years was mentally retarded and had received an operation for cleft lip and palate. the sister had also had a low birth weight (2,300 g). Her sister and mother were compound heterozygotes (mother: R243Q/Y325X; sister: Y325X/P407S). The infant and father were heterozygous carriers (baby: R243Q/ -; father: P407S/ - ).