• 대한전기학회논문지
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• 제41권6호
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• pp.615-624
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• 1992

For the operation of the resonant DC link inverters, only limited number of modulation techniques such as the delta modulation and instantaneous current control techniques have been suggested. However, these modulation techniques have some limitations in practical operation. In this paper, the application of conventional inverter modulation techniques is suggested for the control of the resonant DC link inverter. The harmonic analysis results are presented. The results show that these modulation techniques offer good output characteristics similar to conventional inverter PWM techniques for the operation of the resonant DC link inverter. This implies that not only the delta modulation technique and instantaneous current control techniques but also various other modulation techniques can be applied to the operation of the resonant DC link inverter. This also indicates that open loop control as well as closed loop control can be used for the operation of the resonant inverter. The resonant DC link inverter with various modulation strategies is implemented using V-40 microprocessors.

• 공학교육연구
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• 제24권3호
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• pp.58-69
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• 2021

It is very necessary to have a creative problem-solving capacities to learn various majors and liberal arts based on the major, and to solve the bottleneck techniques led by students. In this study, the existing creative problem-solving curriculums, 'Methodology of Inventive Problem Solving' based on TRIZ, were improved and applied, and industrial bottleneck techniques were provided to students to solve these techniques. To improve the curriculum, 1) improvement of instructional objectives and learning contents, 2) improvement of evaluation methods and contents (reflecting the evaluation of instructor and students), and 3) learning satisfaction survey were conducted in the following order. As a result of the application of the improved curriculum, the level of activities for each team was improved, and when the core process was well understood, the evaluation of team activities was also excellent, but there was a tendency to focus on methods that are relatively easy to apply in the problem solving process. In the final exam (learning contents evaluation), teams with difficult understanding of the TRIZ theory or low team activities showed a relatively high trend, but the difference in level between divisions was slightly reduced.

• Nuclear Engineering and Technology
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• 제53권12호
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• pp.3944-3951
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• 2021

Several reasons such as no free lunch theorem indicate that there is not a universal Feature selection (FS) technique that outperforms other ones. Moreover, some approaches such as using synthetic dataset, in presence of large number of FS techniques, are very tedious and time consuming task. In this study to tackle the issue of dependency of estimation accuracy on the selected FS technique, a methodology based on the heterogeneous ensemble is proposed. The performance of the major learning algorithms of neural network (i.e. the FFNN-BR, the FFNN-LM) in combination with the diverse FS techniques (i.e. the NCA, the F-test, the Kendall's tau, the Pearson, the Spearman, and the Relief) and different combination techniques of the heterogeneous ensemble (i.e. the Min, the Median, the Arithmetic mean, and the Geometric mean) are considered. The target parameters/transients of Bushehr nuclear power plant (BNPP) are examined as the case study. The results show that the Min combination technique gives the more accurate estimation. Therefore, if the number of FS techniques is m and the number of learning algorithms is n, by the heterogeneous ensemble, the search space for acceptable estimation of the target parameters may be reduced from n × m to n × 1. The proposed methodology gives a simple and practical approach for more reliable and more accurate estimation of the target parameters compared to the methods such as the use of synthetic dataset or trial and error methods.

• Interdisciplinary Bio Central
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• 제4권3호
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• pp.7.1-7.8
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• 2012

With the development of many methods of studying the brain, the field of neuroscience has generated large amounts of information obtained from various techniques: imaging techniques, electrophysiological techniques, techniques for analyzing brain connectivity, techniques for getting molecular information of the brain, etc. A plenty of neuroinformatics databases have been made for storing and sharing this useful information and those databases can be publicly accessed by researchers as needed. However, since there are too many neuroinformatics databases, it is difficult to find the appropriate database depending on the needs of researcher. Moreover, many researchers in neuroscience fields are unfamiliar with using neuroinformatics databases for their studies because data is too diverse for neuroscientists to handle this and there is little precedent for using neuroinformatics databases for their research. Therefore, in this article, we review databases in the field of neuroscience according to both their methods for obtaining data and their objectives to help researchers to use databases properly. We also introduce major neuroinformatics databases for each type of information. In addition, to show examples of novel uses of neuroinformatics databases, we represent several studies that combine neuroinformatics databases of different information types and discover new findings. Finally, we conclude our paper with the discussion of potential applications of neuroinformatics databases.

• Journal of Periodontal and Implant Science
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• 제38권2호
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• pp.253-262
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• 2008

Background: Incomplete flap coverage or early exposure over implants and/or barrier membranes have a negative effect on bone regeneration. In cases of using regenerative techniques, complete soft tissue coverage of the implant area is necessary to promote adequate conditions for guided bone regeneration. Primary socket closure may be difficult, when periosteal releasing incision is only used, due to the opening left by extracted tooth. Therefore, Soft tissue grafting techniques are used to achieve primary soft tissue closure. Materials and Methods: Soft tissue grafting techniques, with or without barrier membranes, were performed for primary closure in four cases of immediate placements. Three different methods were used (CTG, VIP-CT, Palatal advanced flap). Clinical results of the grafting were evaluated. Result: One case showed early exposure of cover-screw and, no other complications were noted. In the others, Primary closure was achieved by soft tissue grafting techniques. One of the cases, Graft showed partial necrosis, but there were no exposure over implants and/or barrier membranes. Conclusion: The use of grafting techniques, in immediate implant placement, can predictably obtain primary closure of extraction sockets, thereby providing predictable bone formation and improved implant results.

• 대한인간공학회지
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• 제26권2호
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• pp.15-20
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• 2007

The purpose of this study is to compare assessment techniques for Korean characters entry methods of mobile phones. This study was performed based on survey of relevant existing studies. The assessment techniques were classified into three: 1) predicting entry time using conceptual models such as Fitts' law, Hick-Hyman's law and KLM-GOMS model (conceptual model); 2) counting the number of pressing button(number of pressing button); and 3) measuring performance or rating subjective measures using real mobile phones(real mobile phone). The comparison revealed that the assessment results were different depending upon the techniques used. The results from the conceptual model using only Fitts' law and the number of pressing button were opposite to those from techniques of the real mobile phone and conceptual model using Fitts' and Hick-Hyman's laws. Based on this result and suggestions provided by the literature, it is recommended that for more precisely assessing interfaces of mobile phones such as Korean characters entry method, real mobile phones be used instead of the conceptual models.

• 여성건강간호학회지
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• 제23권3호
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• pp.155-165
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• 2017

Purpose: The aim of this study was to understand the hand-on breast massage techniques used by well-known experts in breastfeeding clinics. Methods: A qualitative multiple-case design was applied that involved a feasibility test. Four experts sampling qualitative data collected by observing participants and in individual interviews were analyzed by content analysis, linking data to the propositions, and cross-case pattern matching. This study explored differences within and between cases, and the possibilities of replicating findings across cases. Thirty-nine postpartum women participated voluntarily in the feasibility test, which investigated the usability of four massage techniques. Results: The four techniques showed considerable similarities in terms of the application of stimulation to the breast base and increased flexibility of the wired flexible body, which was the core mechanism underlying the techniques. The breast management strategies were consistent with existing practice guidelines with the exception of using cold cabbage to control engorgement pain. There was insufficient scientific evidence for supporting the massage techniques used by the experts. All of the techniques showed 100% education completeness, but application rates were higher for self-control-oriented techniques. Conclusion: The massage techniques applied by experts in breastfeeding were based on hypotheses and self-control techniques are feasible to apply in practice.

• Mass Spectrometry Letters
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• 제13권4호
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• pp.95-105
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• 2022

Amatoxin-induced mushroom poisoning starts with nonspecific symptoms of toxicity but hepatic damage may follow, resulting in the rapid development of liver insufficiency and, ultimately, coma and death. Accurate detection of amatoxins, such as α-, β-, and γ-amanitin, within the first few hours after presentation is necessary to improve the therapeutic outcomes of patients. Therefore, analytical methods for the identification and quantification of α-, β-, and γ-amanitin in biological samples are necessary for clinical and forensic toxicology. This study presents a literature review of the analytical techniques available for amatoxin detection in biological matrices, and established an inventory of liquid chromatography (LC) techniques with mass spectrometry (MS), ultraviolet (UV) detection, and electrochemical detection (ECD). LC-MS methods using quadrupole tandem mass spectrometry, time-of-flight mass spectrometry, and orbitrap MS are powerful analytical techniques for the identification and determination of amatoxins in plasma, urine, serum, and tissue samples, with high sensitivity, specificity, and reproducibility compared to LC with UV and ECD, enzyme-linked immunoassay, and capillary electrophoresis methods.

• 한국의사학회지
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• 제20권2호
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• pp.81-86
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• 2007

In ancient East Asia surgical methods existed even before the modern surgical methods were introduced. These surgical methods were mainly used to treat tumor, bruises, and dermatosis. The methods include many techniques such as making incisions in the skin, tell when to operate, and the aftercare following an operation. The traditional ways are not practiced any more due to its being replaced by the anesthesia techniques originating from the West, but the ancient methods can still be found in documents and these methods can be reproduced through such documents. There is a possibility that this ancient method could replace the present day method because of its nature-friendly characteristic as well as its post-operation management.

• 제어로봇시스템학회논문지
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• 제9권6호
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• pp.413-419
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• 2003

The objective of this paper is to survey and put in perspective the existing methods of dynamic filter development. This includes theories and practices for linear and nonlinear filters, multiple model filters, and data association methods for tracking in multitarget environment. The presentation of this paper is motivated by recent surge of interest in the area of designing feedback control systems with reduced number of sensors, detection and identification of abrupt changes, and multitarget tracking in clutter. It is hoped to be useful in view of the need to take a grasp of existing techniques before using them in practice and developing new techniques.