• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.21 no.1
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• pp.51-63
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• 2022

Convoy driving is one of the technologies of multi-vehicle cooperation driving along with platoon driving. All over the world, research on vehicle control mechanisms to maintain vehicle formation during convoy driving convoy driving has been actively conducted and in Europe's Autonet 2030 project has developed and demonstrated convoy driving services for highways. But, even the concept of convoy driving is still insufficient in Korea. Therefore, in this study, the concept of convoy driving service was established and scenarios and communication messages for service application on urban roads were developed. And its effectiveness was verified through simulation analysis. As a result of comparing and analyzing individual vehicle cooperative driving and convoy driving for the blind spot support service and dilemma zone safety support service, which are representative V2I cooperative driving services on urban roads, the number of conflicts(indicator of traffic safety) and delays and stops(indicator of traffic efficiency) are significantly improved in convoy driving compared to individual vehicle cooperative driving.

• Journal of Chest Surgery
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• v.40 no.7 s.276
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• pp.480-484
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• 2007

Background: Major vascular injuries can jeopardize a patient's life or imperil limb survival. We performed this study to establish an optimal management plan for vascular injuries. Material and Method: We retrospectively reviewed 26 cases of vascular injury that were treated at Pusan National University Hospital from May, 1999 to September, 2004. The age and sex distribution, the locations and causes of vascular injury, the diagnostic tools, the degree of injuries, clinical manifestations, the treatment modality and complications were reviewed. Result: The mean age was 39.5 years (range: $12{\sim}86$) and the male to female ratio was 22 : 4. The injuries were in 6 descending thoracic aortas, 4 femoral arteries, 4 popliteal veins and so on. The causes of injury were iatrogenic in 8 cases, traffic accident in 7, stab injury in 6 and industrial accident in 5. The most commonly used diagnostic tools were CT and angiography. The degrees of arterial injury were pseudoaneurysm in 10 cases, partial severance in 5, complete severance in 3 and thrombosis in 3. The degrees of venous injury were partial severance in 6 cases, complete severance in 2 and arteriovenous fistula in 2. The clinical manifestations were absence of pulse in 8 cases, coldness in 7, chest pain in 6, swelling in 5, bleeding in 5 and so on. The most frequently used type of revascularization was graft interposition in 11 cases. Two arteriovenous fistulae were repaired by endovascular procedure. There was one case of mortality due to multi-organ failure after hemorrhagic shock, There were three major amputations, and two of them were due to delayed diagnosis and treatment. Conclusion: A system for the early diagnosis and treatment is essential for improving limb salvage and patient mortality. As a consequence of the widespread application of endovascular procedures, the incidence of iatrogenic injuries has recently increased. Educating physicians is important for the prevention of iatrogenic injury. Easy communication and cooperation for earlier involvement of a vascular surgeon is also an important factor.

• Journal of Chest Surgery
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• v.32 no.9
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• pp.790-798
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• 1999

Background: As the early outcome after coronary artery bypass grafting(CABG) has been stabilized, neurologic complication has now become one of the most important morbidity. The aim of this study was to find out the risk factors associated with the neurologic complications after CABG. Material and Method: In 351 patients who underwent CABG, the incidence and features of neurologic complications, with associated perioperative risk factors, were retrospectively reviewed. Neurologic complication was defined as a new cerebral infarction confirmed by postoperative neurologic examination and radiologic studies, or delayed recovery of consciousness and orientation for more than 24 hours after the operation. Result: Neurologic complications occurred in 18 patients(5.1%), of these nine(2.6%) were diagnosed as having new cerebral infarctions(stroke). Stroke was manifested as motor paralysis in four patients, mental retardation or orientation abnormality in four, and brain death in one. Statistical analysis revealed the following variables as significant risk factors for neurologic complications by both univariate and multivariate analyses: cardiopulmonary bypass longer than 180 minutes, atheroma of the ascending aorta, carotid artery stenosis detected by Duplex sonography, and past history of cerebrovascular accident or transient ischemic attack. Age over 65 years, aortic calcification detected by simple X-ray, and intraoperative myocardial infarction were significant risk factors by univariate analysis only. Neither the severity of carotid artery stenosis nor technical modifications such as cannulation of the aortic arch or single clamp technique, which were expected to affect the inciden e of neurologic complications, had significant relationship with the incidence. Conclusion: This study confirmed the strong association between neurologic complications after CABG and atherosclerosis of the arterial system. Therefore, to minimize the incidence of neurologic complications, systematic evaluation focused on atherosclerotic lesions of the arterial system followed by adequate alteration of operative strategy is needed.

• Clinical and Experimental Pediatrics
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• v.51 no.1
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• pp.62-66
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• 2008

Purpose : In addition to epileptic seizures (ES), a variety of physiologic, organic and psychogenic disorders can manifest as paroxysmal behavioral events. Paroxysmal nonepileptic events (PNEs) are quite encountered in infants, young children, and adolescents. In a substantial proportion of cases, a careful history and examination will elucidate their nature. However, in other cases, it is necessary to differentiate PNEs from ES by video-electroencephalographic (EEG) monitoring. We report our experiences with PNEs in a group of children and adolescents who underwent video-EEG monitoring. Methods : From September, 2004 to June, 2006, one hundred thirty patients were monitored in the Pediatric Epilepsy Monitoring Units of Korea University Guro and Ansan hospitals. Their hospital charts were reviewed and video records of these events were analyzed. We observed all patients after video-EEG monitoring for more than 3 months. Results : Typical spells occurred during monitoring in 33 patients, not associated with a seizure pattern on EEG recordings. Two patients were diagnosed as frontal lobe epilepsy on basis of typical semiology and clinical characteristics, so 31 patients were documented to have PNEs finally. The mean age of patients was $7.2{\pm}5.8\;years$. The male to female ratio was 15 (48.4%) to 16 (51.6%). Among 31 patients, fifteen patients had associated disorders such as epilepsy, developmental delay, cerebral palsy, gastric ulcer, attention deficit hyperactivity disorder or depressive disorder. Somatoform disorder and factitious disorder was frequently seen in children more than 5 years old (P<0.05). Psychogenic disorder was more frequent in female (n=6) than in male (n=2) but there was no statistical significance (P>0.05). Conclusion : Our study suggests that video-EEG monitoring is an important diagnostic tool in the evaluation of paroxysmal behavioral events. With correct diagnosis of the PNEs, several unnecessary treatment could be avoided.

• Pediatric Infection and Vaccine
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• v.14 no.1
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• pp.43-46
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• 2007

Purpose : Neonatal bacterial meningitis has been known that its mortality and morbidity is high and its neurologic complications are common. This study was performed to review of the etiology of neonatal bacterial meningitis in Busan, Korea. Methods : We retrospectively analyzed 21 medical records of patients who were diagnosed neonatal bacterial meningitis in four university hospitals in Busan from January 1997 to December 2005. We analyzed age at onset of symptoms, symptoms at admission, causative organisms, and complications. Results : There were 11 male patients and 10 female patients. One premature neonate was included. 7 patients had symptoms at 2-3 weeks after birth and 6 patients at 1-2 weeks after birth. 18 cases had fever, 8 cases had seizure and some had poor feeding, lethargy and irritability. The most common organism causing neonatal bacterial meningitis was Group B streptococcus (GBS). 11 cases were due to GBS, 3 cases due to E. coli, 3 cases were due to Klebsiella pneumoniae, and 2 cases due to Streptococcus pneumoniae. one Listeria monocytogenes and one Enterobacter cloacae were included. 18 patients were alive and 3 patients died. Mental retardation, developmental delay and epilepsy occurred in a living patient. Conclusions : Although this was a retrospective study, we found that Group B streptococcus (GBS) was the most common organism causing neonatal bacterial meningitis and this data is nearly same as others in the world.

• Clinical and Experimental Pediatrics
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• v.51 no.3
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• pp.315-322
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• 2008

Purpose : Prader-Willi syndrome (PWS) is a complex genetic disorder, caused by the deletion of the paternally derived 15q11-13 region or the maternal uniparental disomy of chromosome 15 (mUPD(15)). In this study, we compared phenotypic differences between those patients whose disease was caused by microdeletion and those caused by mUPD(15). In addition, a comparison of the efficacy of growth hormone (GH) therapy between these two PWS genotypes was analyzed. Methods : Fifty-three patients were diagnosed as having PWS based on molecular and cytogenetic analyses and clinical features. Data that included maternal age, birth weight, a feeding problem in the neonatal period, cryptorchidism, developmental delay or mental retardation, short stature, hypopigmentation, changes in height, weight, and body mass indexes (BMI) before and after GH treatment were obtained by a retrospective review of medical records. The data from the patients with microdeletion were compared with those from the patients with mUPD(15). Results : Of the 53 patients with genetically confirmed PWS, 39 cases had microdeletion and 14 mUPD(15). Maternal ages were significantly higher in the mUPD(15) group, and hypopigmentation and a feeding problem in the neonatal period were more frequent in the microdeletion group. Growth hormone was administered to 20 patients [14 with microdeletion, 6 with mUPD(15)]. There were no differences between the two groups in height velocity, weight and height SDS, and BMI after GH therapy. Conclusion : Phenotype and genotype correlations were observed in Korean PWS patients, such as more advanced maternal ages in the mUPD(15) group and more feeding problems and hypopigmentations in the microdeletion group. Further long-term prospective studies are needed to correlate other aspects of the phenotypes.

• The Journal of Korean Academy of Sensory Integration
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• v.7 no.2
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• pp.23-35
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• 2009

Objective : The purpose of this study is to understand whether group Sensory Integration(SI) therapy has the effect on improvement of motor skill and social function for children with developmental disorder. Method : The subjects were recruited among children received sensory integration therapy at a Children's Development Institute in Dae-Jeon, experimental group is total 5 participating in group sensory integration therapy and control group is also 5 participating in individual sensory integration therapy. The program was constructed for 90 minutes and all children either in the experimental or in the control group went through intervention for 20 weeks. Bruininks-Oseretsky test of Motor Proficiency II, Korean-Scales of Independent Behavior-Revised and Social Maturity Scale were used in order to evaluate the degree of improvement in motor skill and social function. Results : Most children in the experimental group showed improvement in overall aspects of motor skill and the social function comparing pre-intervention with post-intervention, but they did not show any statistically significant differences. However, comparing experimental group with control group, children in the experimental group showed improvement in motor skill and social function. Furthermore, there is statistically significant improvement especially in manual coordination, manual dexterity, and social age and social quotient in Behavior-Revised and Social Maturity Scale. Conclusions : It is found that a group Sensory Integration therapy program has effect on motor skill and social function for children with developmental disorder in this study. In the future study, group SI therapy should be applied for children with diverse diagnosis in order to generalize the effectiveness of therapy.

• Clinical and Experimental Pediatrics
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• v.45 no.9
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• pp.1126-1133
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• 2002

Purpose : Prader-Willi syndrome(PWS) is a complex disorder affecting multisystems with characteristic clinical features. Its genetic basis is an expression defect in the paternally derived chromosome 15q11-q13. We analyzed the clinical features and genetic basis of PWS patients for early detection and treatment. Methods : We retrospectively studied 24 patients with PWS in Department of Pediatrics, Samsung Medical Center, from September 1997 to September 2001. We performed cytogenetic and molecular genetic techniques using high resolution GTG banding techniques, fluorescent in situ hybridization and methylation-specific PCR for CpG island of SNRPN gene region. Results : The average birth weight of PWS patients was $2.67{\pm}0.47kg$ and median age at diagnosis was 1.3 years. The average height and weight of PWS patients under one year at diagnostic time were located in a 3-10 percentile relatively, and a rapid weight gain was seen between two and six years. Feeding problems in infancy and neonatal hypotonia were the two most consistently positive major criteria in over 95% of the patients. In 18 of the 24 cases(75%), deletion of chromosome 15q11-q13 was demonstrated and one case among 18 had an unbalanced 14;15 translocation. In four cases without any cytogenetic abnormality, it may be considered as maternal uniparental disomy and the rest showed another findings. Conclusion : We suggest diagnostic testing for PWS in all infants/neonates with unexplained feeding problems and hypotonia. It is necessary for clinically suspicious patients to undergo an early genetic test. As the genetic basis of PWS was heterogenous and complex, further study is required.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.12 no.1
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• pp.14-22
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• 2012

Objectives: This study was performed to review clinical manifestations of hyperphenylalaninemia patients in Korean. Methods: 178 cases of hyperphenyalaninemia were diagnosed at department of pediatrics, Soonchunhyang University Hospital from January, 1983 to August. We reviewed DNA analysis, MR imaging, EEG, radiography of the left hand and wrist, bone densitometry (BMD), IQ test of hyperphenyalaninemia patients. Results: Out of 178 cases, 161 cases were diagnosed classic phenylketonuria and 17 cases were diagnosed BH4 deficiency. 122 cases performed DNA analysis. R243Q (10.3%), Y204C (9.9%), and IVS4-1G>A (8.1%) mutations were predominant. 22 cases underwent MR imaging. Varying degrees of symmetrical high signal intensity were noted on T2-weighted sequences in the periventricular deep white matter of 15 cases. 23 cases were performed EEG. 12 cases (52.3%) showed abnormal pattern. EEG abnormalities showed in 11 cases. On lumbar BMD four of 11 cases (36%) showed reduced bone density of more than 1 S.D. in four of 11 cases, bone age was less than chronological age by at least one year. 18 cases were performed IQ test. Mean IQ scores was $84{\pm}21.6$. Among older than 15 years (9 cases), Mean IQ scores was $72{\pm}21.2$. PTPS deficiency was 14 cases, DHPR deficiency was 2 cases, and GTPCH deficiency was 1 case. Conclusion: We confirmed there were varieties of DNA mutations. And MR imaging and EEG were nonspecific in PKU patients. Older children showed lower IQ score. Low phenylalanine diet prevents brain damage in PKU patient. Not only first few years of life but also lifetime, Keeping low phenylalanine diet is important.

• Journal of Intelligence and Information Systems
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• v.27 no.1
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• pp.177-190
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• 2021

Due to the development of the fourth industrial revolution technology, efforts are being made to improve areas that humans cannot handle by utilizing artificial intelligence techniques such as machine learning. Although on-demand production companies also want to reduce corporate risks such as delays in delivery by predicting total production time for orders, they are having difficulty predicting this because the total production time is all different for each order. The Theory of Constraints (TOC) theory was developed to find the least efficient areas to increase order throughput and reduce order total cost, but failed to provide a forecast of total production time. Order production varies from order to order due to various customer needs, so the total production time of individual orders can be measured postmortem, but it is difficult to predict in advance. The total measured production time of existing orders is also different, which has limitations that cannot be used as standard time. As a result, experienced managers rely on persimmons rather than on the use of the system, while inexperienced managers use simple management indicators (e.g., 60 days total production time for raw materials, 90 days total production time for steel plates, etc.). Too fast work instructions based on imperfections or indicators cause congestion, which leads to productivity degradation, and too late leads to increased production costs or failure to meet delivery dates due to emergency processing. Failure to meet the deadline will result in compensation for delayed compensation or adversely affect business and collection sectors. In this study, to address these problems, an entity that operates an order production system seeks to find a machine learning model that estimates the total production time of new orders. It uses orders, production, and process performance for materials used for machine learning. We compared and analyzed OLS, GLM Gamma, Extra Trees, and Random Forest algorithms as the best algorithms for estimating total production time and present the results.