• Journal of Korea Game Society
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• v.4 no.4
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• pp.11-18
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• 2004

The on-line games in the past were played by only two persons exchanging data based on one-to-one connections, whereas recent ones (e.g. MMORPG: Massively Multi-player Online Role-playings Game) enable tens of thousands of people to be connected simultaneously. Specifically, Korea has established an excellent network infrastructure that can't be found anywhere in the world. Almost every household has a high-speed Internet access. What made this possible was, in part, high density of population that has accelerated the formation of good Internet infrastructure. However, this rapid increase in the use of on-line games may lead to surging traffics exceeding the limited Internet communication capacity so that the connection to the games is unstable or the server fails. expanding the servers though this measure is very costly could solve this problem. To deal with this problem, the present study proposes the load distribution technology that connects in the form of local clustering the game servers divided by their contents used in each on-line game reduces the loads of specific servers using the load balancer, and enhances performance of sewer for their efficient operation. In this paper, a cluster system is proposed where each Game server in the system has different contents service and loads are distributed efficiently using the game server resource information such as CPU utilization. Game sewers having different contents are mutually connected and managed with a network file system to maintain information consistency required to support resource information updates, deletions, and additions. Simulation studies show that our method performs better than other traditional methods. In terms of response time, our method shows shorter latency than RR (Round Robin) and LC (Least Connection) by about 12%, 10% respectively.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.17 no.2
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• pp.55-62
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• 2017

Gaucher disease (GD) is an autosomal recessive lysosomal storage disorder caused by beta-glucosidase deficiency. An 18 month-old male with hepatosplenomegaly, anemia, thrombocytopenia, and growth retardation referred to our hospital. The patient showed neurological symptoms, such as supranuclear gaze palsy and developmental delay. Bone marrow biopsy performed to rule out malignancy and the results revealed no malignant cell; however, abnormal histiocytes suggesting storage disease was noted. Based on hepatosplenomegaly, bicytopenia and unexplained neurologic manifestations, enzyme activity and genetic analysis were conducted emergently with a strong suspicion of GD. Beta-glucosidase activity in leukocyte was decreased. GBA sequencing to confirm the diagnosis revealed compound heterozygous pathogenic variants (i.e., c.754T>A, c.887G>A), both previously reported as the cause of neuronopathic GD. Under the diagnosis of type 3 GD, the patient immediately received enzyme replacement therapy (ERT). After 17 months of ERT, the size of spleen decreased, and hemoglobin and platelet count returned to normal. In addition, the activity of chitotriosidase and angiotensin converting enzyme decreased. However, myoclonic movement and generalized seizure occurred at the age of 19 months and antiepileptic drug was started. Other neurological deterioration including supranuclear gaze palsy and developmental delay also persisted. A new therapy to overcome neurologic problems should be developed for patients with type 3 GD.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.18 no.1
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• pp.23-29
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• 2018

Carbamoyl phosphate synthetase 1 deficiency (CPS1D) is a rare autosomal recessive urea cycle disorder characterized by hyperammonemia. CPS1D is caused by mutations in the CPS1 gene on chromosome 2q35. Based on the age of onset, there are two phenotypes: the neonatal type and the delayed-onset type. The severity of clinical manifestation depends on the degree of CPS1 residual enzymatic activity, and can result in hyperammonemia and neurological dysfunction. We report a case of CPS1D in a neonate who developed vomiting, decreased consciousness and hyperammonemia at 25th day after birth. She showed excellent response to treatment including hydration, ammonia-lowering drugs and a low-protein diet without hemodialysis. Her growth, development and neurological outcomes were fair at the last follow-up at 17 months of age.

• Therapeutic Science for Rehabilitation
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• v.10 no.2
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• pp.37-51
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• 2021

Objective : The purpose of this study was to analyze non-invasive treatments and drooling assessment methods in children with cerebral palsy and developmental disabilities, who drool. Methods : This study searched two hundred papers published in 2005-2019. Forty-four papers were selected based on their abstract and title, and ten papers were finally selected following a secondary search. Results : The PEDro Scale of the selected papers was high with an average of seven points. As a result of analyzing the overall trends, the study participants were primarily patients with cerebral palsy, and recently, the therapeutic intervention of oral sensory exercise was more actively studied than behavioral modification. Studies of behavioral modification and oral sensory exercise intervention methods were found to have differences in participant age and, cognitive level, number of participants, research design, treatment time, and duration. Studies to confirming the frequency and severity of the drooling measurement method were found to be the main factor. Conclusion : This study analyzed typical behavioral modification and oral sensory exercise interventions as examples of non-invasive therapeutic interventions for children with cerebral palsy and developmental disabilities and provided information to help select appropriate therapeutic intervention methods when planning non-invasive therapy using behavioral modification and oral sensory exercise therapy.

• Journal of Food Hygiene and Safety
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• v.27 no.1
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• pp.74-80
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• 2012

Fish contain both the neurotoxin methyl mercury (MeHg) and nutrients important for brain development. The developing brain appears to be most sensitive to MeHg toxicity and mothers who consume fish during pregnancy expose their fetus prenatally. Although brain development is most dramatic during fetal life, it continues for years postnatally and additional exposure can occur when a mother breast feeds or the child consumes fish. This raises the possibility that MeHg might influence brain. We evaluated the relationship between fish consumption and mercury exposure levels in umbilical cord blood of the pregnant women of the city of Tongyeong city, Korea. A total of 159 pregnant women residing in the city of Tongyeong, Korea were recruited for the study between October 2010 and March 2011. Fish consumption was evaluated using food frequency questionnaires including detailed questions on fish consumption. We used ANOVA to estimated the particular relevance between the frequency of fish consumption and the umbilical cord blood mercury concentration, and other various factors. The average mean concentration of mercury levels in umbilical cord blood of pregnant women who participated in our study were $2.69{\pm}2.50ppb$, ranging from 0.01 to 14.80 ppb. The mean concentration of umbilical cord blood mercury exposure was lower than the level recommended by WHO (5.0 ppb), but the mercury exposure level exceeded the WHO recommended in 17 (10.7%) cases of umbilical cord blood. Mercury levels in cord blood of pregnant women were $2.04{\pm}2.00ppb$, ranging from 0 to 8.00 ppb in below 29 years old and $3.18{\pm}2.74ppb$, ranging from 0.01 to 14.80 ppb in more 30 years old. In this study, there was a significant difference for the frequency of eating fish between the groups (p < 0.01). The level of the groups that ate fish 3 to more times per week ($4.15{\pm}4.02ppb$) was significant higher as compared with the level of other groups that ate fish 1 to times per week ($2.63{\pm}2.22ppb$) and none per week ($1.06{\pm}1.44ppb$), respectively. We found that the mercury concentration of umbilical cord blood associate with fish consumption and this was statistically significant and this fact revels that fish consumption is positively related to mercury levels in the umbilical cord blood. We need systematic and periodic research on the general population to prevent mercury poisoning, which can be cause by low-level mercury exposure from dietary intake such as chronic fish consumption.

• Clinical and Experimental Pediatrics
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• v.52 no.4
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• pp.458-463
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• 2009

Purpose : Schizencephaly is a uncommon congenital brain anomaly characterized by congenital clefts spanning the cerebral hemispheres from pial surface to lateral ventricles and lined by gray matter. In this study, we investigated the clinical manifestation and radiologic findings of pediatric schizencephaly. Methods : The data of 13 patients who were diagnosed with schizencephaly in Severance Childrens Hospital and Yongdong Severance Hospital from January 2005 to December 2007 were analyzed retrospectively. Results : The mean age at diagnosis was $9.08{\pm}2.67$ months old and ranged from 1 to 30 months. The ratio of male to female patients was 3.33:1. Five (38.5%) patients had bilateral clefts, while 8 (61.5%) had unilateral clefts. Five (38.5%) patients had closed lip clefts, and 4 (30.8%) had opened lip clefts. Four (30.8%) patients had multiple clefts. Associated anomalies showed in all cases. The clinical features consisted of mild unilateral weakness in 7 (53.8%) cases and a hemiparesis was present in 3 (23.1%) patients. A tetraparesis was in 3 (23.1%) patients. There was no difference in motor deficit between unilateral and bilateral clefts. Delayed development was observed in all cases. Epilepsy was present in 7 (53.8%) patients, 5 patients with unilateral clefts and 2 patients with bilateral clefts. Three (42.8%) patients showed intractable seizures. Conclusion : Schizencephaly showed variable clinical manifestations and radiologic findings in association with the types and locations of the clefts. It is necessary to diagnose schizencephaly early and to detect the development of epilepsy. Intensive and large studies of the correlation of clinical outcomes and radiologic findings should be continued for more effective treatment.

• The Journal of Korean Academy of Sensory Integration
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• v.16 no.3
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• pp.34-49
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• 2018

Objective : This study aimed to examine the psychometric properties of Korean version of Pediatric Volitional Questionnaire (PVQ-K) using classical test theory. Methods : For the translation of Pediatric Volitional Questionnaire (PVQ), as recommended in the literature, four-stage translation method was used. For the psychometric properties of Korean version of the Pediatric Volitional Questionnaire (PVQ-K), internal consistency reliability, content validity, and construct validity of the test using the known groups method and convergent and divergent methods were examined. For the recruitment of participants, a convenience sampling method is used. Participants of this study were 10 children with neuro-developmental disabilities hospitalized two different rehabilitations center and 10 children with typical development living in Daejeon, South Korea. All 20 participants were in aged from two to five years. Results : In terms of the content validity index, it was over 0.78, confirmed by nine experts of children development. PVQ-K successfully discriminated the scores of children with typical development from those with neurodevelopmental disabilities (p < .05). It is found that there is significant correlations between achievement stage of PVQ-K and the Korean Developmental Screening Test for Infants & Children (K-DTS)(.652 ~ .799 for subcategory, .706 for total scale). The internal consistency was .944 (Cronbach's ${\alpha}$). In qualitative content analysis, it was examined that how Korean children behave and respond in the environment, and how children's volition was strengthened or weakened by the environment. Conclusion : The results propose that PVQ-K can be a useful occupation-focused measure. This study recommend further study on PVQ-K with larger samples combined with the item-response theory approach.

• Journal of Preventive Medicine and Public Health
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• v.26 no.4 s.44
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• pp.628-649
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• 1993

This study was conducted to investigate the factors related to the poor school performance of the elementary school children. Two schools in Taegu, one in the affluent area and the other in the poor area, were selected and a total of 175 children whose school performance was within low 10 percentile (poor performers) and 97 children whose school performance were within high 5 percentile (good performers) in each class of 2nd, 4th and 6th grades were tested for the physical health, behavioral problem and family background. Each child had gone through a battery of tests including visual and hearing acuity, anthropometry (body weight, height, head circumference), intelligence (Kodae Stanford-Binet test), test anxiety (TAI-K), neurologic examination by a developmental pediatrician and heavy metal content (Pb, Cd, Zn) in hair by atomic absorption spectrophotometry. A questionnaire was administered to the mothers for prenatal and prenatal courses of the child, family environment, child's developmental history, and child's behavioral and learning problems. Another questionnaire was administered to the teachers of the children for the child's family background, arithmatic & language abilities and behavioral problem. The poor school performance had a significant correlation with male gender, high birth order, broken home, low educational and occupational levels of parents, visual problem, high test anxiety score, attention deficit hyperactivity disorder (ADHD), poor physical growth (weight, height, head circumference) and low I.Q. score. The factors that had a significant correlation with the poor school performance in multiple logistic regression analysis were child's birth order (odds ratio=2.06), male gender(odds ratio=5.91), broken home(odds ratio=9.29), test anxiety score(odds ratio=1.07), ADHD (odds ratio=9.67), I.Q. score (odds ratio=0.85) and height less than Korean standard mean-1S.D.(odds ratio=11.12). The heavy metal contents in hair did not show any significant correlation with poor school performance. However the lead and cadmium contents were high in males than in females. The lead content was negatively correlated with child's grade(P<0.05) and zinc was positively correlated with grade (P<0.05). among the factors that showed a significant correlation with the poor school performance, high birth order, short stature and ADHD may be modified by a good family planning, good feeding practice for infant and child, and early detection and treatment of ADHD. Also, teacher and parents should restrain themselves from inducing excessive test anxiety by forcing the child to study and over-expecting beyond the child's intellectual capability.

• Investigative Magnetic Resonance Imaging
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• v.15 no.2
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• pp.110-122
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• 2011

Purpose : The purpose of this study is to establish the method generating human brain anatomical connectivity from Korean children and evaluating the network topological properties using small-world network analysis. Materials and Methods : Using diffusion tensor images (DTI) and parcellation maps of structural MRIs acquired from twelve healthy Korean children, we generated a brain structural connectivity matrix for individual. We applied one sample t-test to the connectivity maps to derive a representative anatomical connectivity for the group. By spatially normalizing the white matter bundles of participants into a template standard space, we obtained the anatomical brain network model. Network properties including clustering coefficient, characteristic path length, and global/local efficiency were also calculated. Results : We found that the structural connectivity of Korean children group preserves the small-world properties. The anatomical connectivity map obtained in this study showed that children group had higher intra-hemispheric connectivity than inter-hemispheric connectivity. We also observed that the neural connectivity of the group is high between brain stem and motorsensory areas. Conclusion : We suggested a method to examine the anatomical brain network of Korean children group. The proposed method can be used to evaluate the efficiency of anatomical brain networks in people with disease.

• Journal of Life Science
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• v.19 no.3
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• pp.317-321
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• 2009

Down syndrome (DS) results from overexpressed genes on an extra copy of human chromosome 21. Among various phenotypes seen in DS patients, mental retardation, such as learning and memory deficits, is a major factor that prevents DS individuals from leading fully independent lives. The Dyrk1A gene that plays a critical role in neurodevelopment has been isolated from chromosome 21, and transgenic mice with over-expression of Dyrk1A show severe hippocampal dependent learning and memory defects. In the present study, as an initial step to test the treatment of Dyrk1A dependent mental retardation phenotypes in model animals, we isolated human Dyrk1A specific lentiviral short hairpin RNA (shRNA) that inhibits the exogenous human Dyrk1A expression, but not the endogenous mouse expression in transgenic mice with human Dyrk1A overexpression. This limited and specific repression of exogenous human Dyrk1A will prove to be valuable information, if Dyrk1A dependent learning and memory defects in DS patients could be treated or at least ameliorated in vivo.