• 대한소아치과학회지
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• 제38권4호
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• pp.435-440
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• 2011

상악 견치의 매복은 소아치과 의사가 흔히 접할 수 있는 맹출장애이며, 이를 방치하였을 경우 인접치의 치근 흡수, 낭종 형성 등의 임상적인 문제점을 유발할 수 있다. 이에 대한 치료는 간단한 유치 발치에서부터 매복치아의 교정적 견인, 외과적 자가이식 등 다양한 방법을 고려할 수 있다. 이 중 자가 이식은 매복치아가 교정적 견인술을 시행하기 어려운 위치에 존재하거나 재위치 시키는데 실패했을 경우에 매복치아의 발거에 앞서 고려할 수 있으며, 그 예후는 치근의 완성도, 환자연령, 외과적 술식, 근관치료 시기, 치아고정 기간 등에 의해 결정된다. 본 두 증례들은 혼합치열기 말기에 상악 견치가 매복된 환자에서 그 매복 위치가 자발적인 맹출 유도나 교정적 견인 및 배열이 어렵다고 판단된 경우이며, 자가 이식 후 근관치료와 교정 치료를 시행하고 현재까지 성공적으로 유지되고 있어 보고하는 바이다.

• 치위생과학회지
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• 제23권3호
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• pp.225-235
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• 2023

Background: This study aimed to analyze the effects of periodontal treatment and individual- and tooth-related factors on tooth extraction in people with disabilities. Methods: The Korea National Health Insurance claims data of individuals with disabilities aged 40~64 years with chronic periodontitis in 2008 were obtained. Of these, data on the disabled who underwent scaling/root plaining, subgingival curettage/periodontal surgery, or non-periodontal treatments, and data on their teeth were selected. The extraction of 716,688 teeth from 39,097 patients was tracked until 2018, and the patient- and tooth-level factors related to tooth loss were identified using a mixed-effect logistic regression analysis. Results: Data from approximately 17% of the teeth were extracted during a follow-up period of approximately 11 years. Among the tooth-level variables, scaling/root planing treatment at baseline and periodontal treatment during the follow-up period were associated with a lower risk of tooth loss (odds ratio=0.692 and 0.769, respectively, p<0.001). Non-vital teeth increased the risk of tooth loss by 3.159 times (p<0.001). Among the patient-level variables, females were less likely to have lost their teeth than males, and those with orthopedic impairment or brain lesions/mental disabilities, a higher age group, lower income level, or residents in medium/small cities or rural areas were more likely to have lost their teeth (p<0.001). Conclusion: Through approximately 11 years of follow-up, scaling or root planing, experience with periodontal treatment at least once, female sex, older age, lower income, smaller residential areas, type of disability, and pulp vitality were found to be associated with tooth loss in individuals with disabilities aged 40~64 years with chronic periodontitis. To prevent tooth loss in individuals with disabilities, it is necessary to establish a dental treatment plan that considers the timing of periodontal treatment and the characteristics of the patient and teeth.

• 산업공학
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• 제23권2호
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• pp.182-192
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• 2010

Customer needs for final products are very unpredictable because product specifications and technologies are being improved very quickly thereby their requirement level is also elevated correspondingly. In order to survive and to enhance competitiveness in the global market, many manufacturing companies are trying to find a breakthrough from collaborization. Even though they want to collaborate with others, however, they do not exactly know what kind of system they have to develop or which technology they have to use. In this paper, therefore, we first investigate status and trend of information systems and infrastructure that are essential for collaboration. We then clearly describe definition and classification of collaboration with various point of views considering collaboration pattern, timing condition of collaborative activities, organizational structure, etc. With web-based collaboration systems already developed by i-Manufacturing (Korean-style Manufacturing Innovation) project, led by Korean government from 2004, we introduce main functions and analyze collaboration types of each system. Strategically important technologies for supporting collaboration will also be illustrated by reorganizing collaborization technologies after evaluating them with respect to emergency and importance of each technology. We hope this research will provide a guideline on collaboration especially for small and medium sized manufacturing companies.

• Journal of information and communication convergence engineering
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• 제13권3호
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• pp.180-188
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• 2015

As a potential alternative to the complementary metal-oxide semiconductor (CMOS) technology, many researchers are focusing on carbon-nanotube field-effect transistors (CNFETs) for future electronics. However, existing studies report the advantages of CNFETs over CMOS at the device level by using small-scale circuits, or over outdated CMOS technology. In this paper, we propose a methodology of analyzing CNFET-based circuits and study its impact at the full-chip scale. First, we design CNFET standard cells and use them to construct large-scale designs. Second, we perform parasitic extraction of CNFET devices and characterize their timing and power behaviors. Then, we perform a full-chip analysis and show the benefits of CNFET over CMOS in 45-nm and 20-nm designs. Our full-chip study shows that in the 45-nm design, CNFET circuits achieve a 5.91×/3.87× (delay/power) benefit over CMOS circuits at a density of 200 CNTs/µm. In the 20-nm design, CNFET achieves a 6.44×/3.01× (delay/power) benefit over CMOS at a density of 200 CNTs/µm.

• 웰빙융합연구
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• 제5권1호
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• pp.1-7
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• 2022

Purpose: This study aimed to investigate spatial and temporal features of motor control in an individual with hemiparesis during the curvilinear gait (CG) and proposed an exercise guideline. Research design, data and methodology: An individual aged 63 with hemiparesis by stroke disease was participated in the study. Autoencoder (AE) was used to extract four motor modules from eight muscle activities of the paretic leg during CG. After extraction, each module of four modules was operationally defined by numbering from M1 to M4 according to spatial and temporal features and compared with results reported in a previous study. Results: As a result, an individual with hemiparesis had motor module problems related to difficulty of weight acceptance (module 1), compensation for the weakness of ankle plantar flexor (module 2), a spastic synergistic pattern (module 3) and difficulty with transition from the swing to stance phase (module 4) in terms of spatial features. Also, a delayed activation timing of temporal motor module (module 2) related to the forward propulsion during CG was observed. Conclusions: Gait rehabilitation for the stroke will need to consider clinical significances in respect of the deterioration of motor module and provide the tailored approaches for each gait phase.

• ETRI Journal
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• 제45권2호
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• pp.346-357
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• 2023

Hardware security primitives, also known as physical unclonable functions (PUFs), perform innovative roles to extract the randomness unique to specific hardware. This paper proposes a novel hardware security primitive using a commercial off-the-shelf flash memory chip that is an intrinsic part of most commercial Internet of Things (IoT) devices. First, we define a hardware security source model to describe a hardware-based fixed random bit generator for use in security applications, such as cryptographic key generation. Then, we propose a hardware security primitive with flash memory by exploiting the variability of tunneling electrons in the floating gate. In accordance with the requirements for robustness against the environment, timing variations, and random errors, we developed an adaptive extraction algorithm for the flash PUF. Experimental results show that the proposed flash PUF successfully generates a fixed random response, where the uniqueness is 49.1%, steadiness is 3.8%, uniformity is 50.2%, and min-entropy per bit is 0.87. Thus, our approach can be applied to security applications with reliability and satisfy high-entropy requirements, such as cryptographic key generation for IoT devices.

• 한국항공운항학회지
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• 제32권2호
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• pp.151-158
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• 2024

Microalgae are aquatic microorganisms capable of photosynthetic growth using water, carbon dioxide and sunlight, and can replace petroleum for transportation. It is receiving great attention as a potential next-generation biological resource. The microalgae biodiesel production process is largely based on the development of highly efficient strains and mass production. It consists of cultivation, harvesting, oil extraction, fuel conversion and by-product utilization. Currently, microalgae diesel is 3-5 times more expensive than petroleum diesel. However, with the optimization of each element technology and the development of integrated systems, not only biofuels, but also industrial materials, wastewater treatment, and greenhouse gases As application expands to various fields such as abatement, the timing of commercialization may be brought forward. Oil prices have recently fallen due to the influence of sail gas. Although there has been a significant drop, global warming is an urgent challenge for current and future generations. In particular, Korea, which does not have oil resources, We must always prepare for political environmental changes, high oil prices, and energy crises. In this paper, the need for eco-friendly biofuel for carbon dioxide conversion. In addition to research trends, domestic and international research trends, and economic prospects, the concept of microalgae and the element technologies of the biodiesel production process are briefly discussed introduced.

• 대한소아치과학회지
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• 제32권3호
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• pp.403-408
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• 2005

치아유착은 치근의 상아질 또는 백악질이 치조골과 융합된 것으로 치아의 맹출이상을 야기하여 치조골 성장의 장애를 일으킨다. 본 6세 여아는 유구치의 유착과 영구 소구치의 결손을 주소로 본과에 의뢰되었으며 특이할 만한 의과적, 치과적 병력은 없었다. 구강 검진 소견상 상, 하악의 좌, 우측 유구치에서 저위교합이 관찰되었으며, 다수의 치아우식증이 존재하였다. 방사선 사진 검사 소견상 상악의 좌, 우측 영구 견치와 계승 소구치의 결손, 상악 유구치의 치근흡수와 하악 유구치의 치주인대공간의 소실 및 미약한 치근흡수가 관찰되었다. 계승 영구치의 결손을 동반한 유구치 유착시 치료목표는 적절한 치조골 성장과 유치의 유지이며, 유착의 발현 시기와 치근의 흡수 정도에 따라 관찰, 수복 또는 발치 등의 치료를 고려할 수 있다. 유착치아의 발치는 인접 치조골 성장에 문제가 없고 인접치의 경사가 일어나지 않도록 최대성장점(growth spurt)을 고려하여 그 시기를 결정해야 한다.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제31권3호
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• pp.207-215
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• 2009

Purpose: The aim of the present study is to evaluate the long term bone healing after horizontal ridge augmentation using auto block bone graft for implant installation timing. Materials and Methods: Five Beagle dogs(which were 14 months old and weighted approximately 10kg). In surgery 1(extraction & bone defect), premolars(P2, P3,P4) were extracted and the buccal bone plate was removed to create a horizontally defected ridge. After three months healing, in surgery 2(ridge augmentation). Auto block bone grafts from the mandibular ramus were used in filling the bone defects were fixed with stabilizing screws. The following fluorochrome labels were given intravenously to the beagle dogs: oxytetracycline 1week after the surgery, alizarin red 4 weeks after the surgery, calcein blue 8 weeks after the surgery. The tissue samples were obtained from the sacrificed dogs of 1, 4, 8, 12, 16 weeks after the surgery. Non-decalcified sections were prepared by resin embedding and microsection to find thickness of $10{\mu}m$ for the histologic examination and analysis. Results: 1. We could achieve the successful reconstruction of the horizontal bone defect by auto block bone graft. The grafted bone block remained stable morohologically after 16 weeks of the surgery. 2. In the histologic view. We observed osteoid tissue from the sample $4^{th}$ week sample and active capillary reconstruction in the grafted bone from the $12^{th}$ week sample. Healing procedures of auto bone grafts were compared to that of the host bone. 3. Bone mineralization could be detected from the $8^{th}$ week sample. 4. Fluorochrome labeling showed active bony changes and formation at the interface of the host bone and the block graft mainly. Bony activation in the grafted bone could be seen from the $4^{th}$ week samples. Conclusions: Active bone formation and remodeling between the grafted bone and host bone can be seen through the revascularization. After the perfect adhesion to host bone, Timing of successful implant installation can be detected through the ideal ridge formation by horizontal ridge augmentation.

• 대한소아치과학회지
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• 제43권3호
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• pp.246-253
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• 2016

과잉치의 발거시기는 조기발거와 지연발거로 나뉠 수 있으며 각각의 장단점이 있으며 특히 상악 중절치에 미치는 영향이 크다. 이 연구에서는 과잉치 발거 후 3개월 이상 추적관찰이 시행된 166명을 조사하여 최적의 과잉치 발거시기를 결정하고자 하였다. 환자의 나이가 어리고, 상악 중절치 미맹출 혹은 발육단계가 낮고, Hellman's dental stage상 낮은 단계에서 정중선 변위는 적게 일어났다. 정중이개와 상악 중절치의 회전, 추적 관찰 기간에 따른 변화는 통계적 유의성이 없었다. 상악 중절치가 아직 맹출하지 않은 경우라 하더라도 파노라마 방사선 사진을 촬영하여 정중선 변위가 보인다면 이른 시기에 과잉치를 발거할 필요가 있다. 이 연구는 상악 중절치의 위치 변위에 따라 과잉치의 발거시기를 결정하는 데에 도움을 줄 수 있을 것이다.