• The Korean Journal of Applied Statistics
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• v.32 no.5
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• pp.671-681
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• 2019

Studies on predicting arrhythmia using machine learning have been actively conducted with increasing number of arrhythmia patients. Existing studies have predicted arrhythmia based on multivariate data of feature variables extracted from RR interval data at a specific time point. In this study, we consider that the pattern of the heart state changes with time can be important information for the arrhythmia prediction. Therefore, we investigate the usefulness of predicting the arrhythmia with multivariate time series data obtained by extracting and accumulating the multivariate vectors of the feature variables at various time points. When considering 1-nearest neighbor classification method and its ensemble for comparison, it is confirmed that the multivariate time series data based method can have better classification performance than the multivariate data based method if we select an appropriate time series distance function.

• Journal of the Korean Orthopaedic Association
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• v.56 no.2
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• pp.117-124
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• 2021

Although current surgical techniques have reduced the incidence of malunion, it is still observed because of the complexity of the fracture or associated injuries. Osteotomy is needed when the amount of malunion is expected to result in an overload of cartilage and instability of the joint. Preoperative planning is essential when performing an osteotomy for malunion. Inadequate planning can result in serious complications, such as iatrogenic malalignment, intraoperative fracture, postoperative recurrence of deformity, or soft tissue injuries. In addition, a poor functional result can occur secondary to poor patient selection. This review article includes the surgical indications and planning to correct malunion. Various methods of corrective osteotomy are described according to the kinds of plane and fixation implants.

• Journal of Dental Rehabilitation and Applied Science
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• v.39 no.4
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• pp.204-213
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• 2023

Invasive or non-invasive reduction of fractures could be conducted as treatments of traumatic maxillofacial bone fractures. But when suboptimal reduction or malunion of maxillofacial bone fracture occurs, malocclusion could occur as a result of the lost relationship of the mandible and midface. This malocclusion is called post-traumatic malocclusion and orthognathic surgery, orthodontic treatment, selective grinding and prosthetic reconstruction are suggested as treatments for post-traumatic malocclusion after securement of stable TMJ. Stable TMJ is essential for occlusal rehabilitation to prevent occlusal change and relapse of malocclusion. Centric relation and adapted centric posture are suggested as start points of occlusal rehabilitation because they are most stable TMJ position. This case report presents a case in which post-traumatic malocclusion occurred after reduction of panfacial fracture. To rehabilitate full mouth occlusion, selective grinding and prosthetic reconstruction of implant supported fixed prostheses were conducted in centric relation and showed satisfying results in functional and occlusal aspects.

• 한국노년학
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• v.38 no.1
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• pp.83-102
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• 2018

According to socioemotional selectivity theory, if people perceive their time left in life as expanded, they have a future-oriented goal of life, but if perceive as limited the goal of life is changed into the pursuit of present emotional satisfaction. Thus, if we perceive our time left as getting limited as we get older, we pay more attention to the positive stimuli than the negative ones and remember more the positive stimuli in order to maintain the current emotional state as positive. This is known as the positivity effect. This study examined whether the positivity effect is caused by a limited future time perspective. The participants were presented with scenarios for hypothetical situations in which the future time was expanded or limited, and were encouraged to immerse in the virtual situation by talking about what they would like to do and whom they wanted to spend time with. Then the participants were presented with 48 positive, negative, and neutral emotional pictures and were asked to recall after 10 minutes delay. 75 university students and 65 elderly participated in the study. In the control condition where the future time perspective was not manipulated, the elderly showed the positivity effect but the youth showed the bias toward negative pictures. The elderly in the expanded time condition recalled positive pictures less and negative pictures more than the elderly in the control condition. On the other hand, the youth in the limited time condition recalled less the negative pictures than the youth in the control condition. These results demonstrated that the elderly did not show the positive bias when the future time perspective was expanded, and that the youth showed the positive bias when the future time perspective was limited. These results show that the positivity effect is related with the limited future time perspective.

• The Journal of the Korea Contents Association
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• v.20 no.4
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• pp.658-672
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• 2020

The purpose of this study is to empirically compare statistical models for pre-service teachers' help networks. We identified similarities and differences based on the results of the binary and valued ERGM. Research questions are as follows: First, what are the similarities of factors influencing the binary/valued help network for pre-service teachers? Second, what are differences of factors influencing the binary/valued help network for pre-service teachers? We measured 42 pre-service teachers with focus on their help and friend networks, happiness, and personal characteristics. Results indicated that, first, the similar factors influencing the binary and valued help network of pre-service teachers were local dependencies (reciprocity, transitivity), similarity (major, gender), activity (early childhood education, negative emotion), popularity (early childhood education) and multiplicity (friend network). Second, the difference between factors affecting pre-service teacher's binary and valued help network was the effect of activity (physical education) and popularity (GPA, negative emotion). Based on these findings, we presented implications.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.12
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• pp.1542-1550
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• 2019

Legacy studies for classifying arrhythmia have been studied to improve the accuracy of classification, Neural Network, Fuzzy, etc. Deep learning is most frequently used for arrhythmia classification using error backpropagation algorithm by solving the limit of hidden layer number, which is a problem of neural network. In order to apply a deep learning model to an ECG signal, it is necessary to select an optimal model and parameters. In this paper, we propose optimal parameter extraction method based on a deep learning. For this purpose, R-wave is detected in the ECG signal from which noise has been removed, QRS and RR interval segment is modelled. And then, the weights were learned by supervised learning method through deep learning and the model was evaluated by the verification data. The detection and classification rate of R wave and PVC is evaluated through MIT-BIH arrhythmia database. The performance results indicate the average of 99.77% in R wave detection and 97.84% in PVC classification.

• Applied Microscopy
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• v.41 no.1
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• pp.37-45
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• 2011

Known as a female hormone, estrogen, has an effect on the male reproductive organs. The estrogen has to combine with the estrogen receptor to communicate a signal. Propyl pyrazole triol (PPT) is an estrogen receptor alpha selective agonist with a 410-, or 1,000-fold relative binding affinity for estrogen receptor alpha versus estrogen receptor beta. In this study, adult male mice were treated weekly with subcutaneously injections of PPT (0.01 mg, 0.1 mg, 1mg and 4 mg) suspended in castor oil (as control) for 8 weeks and observed histologically changes in testis, efferent ductule and epididymis. In the high concentrations of PPT 4 mg treatment group, a remarkable reduction was observed in the weight of the body, testis and epididymis. Microscopic examination revealed a reduction in seminiferous tubular diameter of the testis, and epithelial cell height of the epididymis in treated group during the experiment. In addition, as the diameter of the efferent ductule increased gradually, the height of epithelial cells was decreased. PPT 4 mg treatment group caused inhibition of spermatogenesis due to atrophied germinal epithelium in the testis, and decrease of adipocyte size attached to the epididymis. Sperm was not observed in the caudal epididymis of PPT 4 mg treated group. In conclusion, the injection of high concentrations of PPT into adult male mice induced physiological changes, such as an inhibition of spermatogenesis, and also histological changes within the reproductive organs.

• Journal of the korean academy of Pediatric Dentistry
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• v.39 no.4
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• pp.339-347
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• 2012

There still remains a controversial debate whether facial skeletal morphological differences exist between patients with nasal and mouth breathing habits. The aim of this study is to assess a relationship between over a period of time mouth breathing and facial skeletal morphology by analyzing lateral cephalometric radiographs of patients with nasal or mouth breathing habits. A total of 120 patients with skeletal class I, II, and III, who had undergone orthodontic diagnosis in department of pediatric dentistry - chonbuk national university, were chosen and their lateral cephalometric radiographs were analyzed. These patients were divided into six groups of 20, each with or without mouth breathing habits. The result of this study has not showed noticeable differences in cephalometric measurements between nasal and mouth breathing children of skeletal class I, II, and III (p > 0.05). However, when the groups were divided by age factor, mouth breathers of age 12 and older showed significant differences in cephalometrics such as decreased ramus height, maxillary retrusion, and clockwise pattern of mandible than children under age 12 (p < 0.05). In conclusion, a longer period of mouth-breathing habits in children displayed a greater chance of impaired facial growth.

• Journal of the korean academy of Pediatric Dentistry
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• v.40 no.1
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• pp.21-27
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• 2013

In growing children it is frequently found that dental maturation is strongly influenced by the growth rate of maxilla or mandible. If there is evidence to prove this, it might be utilized as a criterion in the early diagnosis of skeletal malocclusion, even before the object's real skeletal features are yet revealed. The purpose of this study was to find out if the difference of dental maturation in over-grown mandible in children with skeletal Class III has any relationship with some skeletal features of mandible. 50 patients in Hellman dental age IIIA with normal occlusion and Class III malocclusion of mandibular over-growth type respectively were selected as study objects. The age estimation was performed on maxillary and mandibular teeth, eruption rate of the 2nd molars of each group have been measured on panoramic radiography, and the differences in dental age of the upper and lower jaw were analyzed under Demirijian's method. The results were as follows: The difference of dental age of maxillary and mandibular teeth between the two groups was 0.66 and 1.20 years respectively, with a higher difference in the experimental group (p < 0.05). The difference of eruption rate of the maxillary and mandibular second molar was not found between two group (p >0.05).

• Proceedings of the Korean Information Science Society Conference
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• 2012.06a
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• pp.334-336
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• 2012

EEG 신호에 대한 연구는 의학, 신경과학, 심리학, 컴퓨터과학, 전자 공학 등 여러 학문 분야에서 많은 연구가 진행되고 있다. EEG 신호는 추출하는데 있어서 필연적으로 각종 Artifact와 분석대상이 아닌 신호가 혼재되어 분석 결과의 부정확성을 가지고 있어 EEG 신호의 활용이 주목받은지 오래되었지만 충분히 활용되지 못하고 있다. 이 문제를 해결하기 위해 각종 필터링 연산 등을 통하여 잡음을 제거하고 혼재된 신호를 분류해 내고 있지만, 잡음제거나 신호분류에 사용되는 방법이 고정된 수식을 이용하는 방법이기 때문에 유연한 측정 및 분류를 할 수 없는 것이 현실이다. 본 논문에서 제안하는 매개변수 선택형 시스템은 정제되지 않은 EEG 신호에서 잡파를 제거하고 정제된 신호에서 분석에 필요한 특징을 추출하는데 있어 사용자에게 착용된 EEG 신호 측정기기에서 전극채널, 신호발생영역 및 주파수 대역 등의 매개변수를 선택하고 필요에 따라 매개변수에 가중치를 부여함으로써, 측정의 정확성을 높이고 EEG 신호의 활용에 신뢰도를 향상 시킬 수 있다.