• 대한족부족관절학회지
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• 제23권1호
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• pp.31-34
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• 2019

Chondroblastoma is a rare benign tumor that produces giant cells and cartilage matrix. The tumor occurs in people between 10 and 25 years with slightly higher incidence in males. The condition occurs in the proximal epiphysis of the tibia and humerus, distal epiphysis of the femur, but its occurrence in the talus is relatively rare, accounting for 4% of the total number of chondroblastoma cases. Chondroblastoma is often misdiagnosed as a primary aneurysmal bone cyst, giant cell tumor, chondromyxoid, and lesion of a secondary aneurysmal bone cyst by fibrous dysplasia. The most commonly used surgical method for chondroblastoma is broad curettage with bone grafting. In general, an aneurysmal bone cyst is associated with a second degree chondroblastoma, which is approximately 20%. Chondroblastoma of the talus and secondary aneurysmal bone cysts can be misdiagnosed as primary aneurysmal bone cysts. This paper reports a case of a young male patient with chondroblastoma of the talus, which was initially misdiagnosed as an aneurysmal bone cyst with involvement of the talo-navicular joint.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.637-639
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• 2003

As the number of spectral bands of high spectral resolution data increases, the capability to detect more detailed classes should also increase, and the classification accuracy should increase as well. Often, it is impossible to access enough training pixels for supervise classification. For this reason, the performance of traditional classification methods isn't useful. In this paper, we propose a new model for classification that operates based on decision fusion. In this classifier, learning is performed at two steps. In first step, only training samples are used and in second step, this classifier utilizes semilabeled samples in addition to original training samples. At the beginning of this method, spectral bands are categorized in several small groups. Information of each group is used as a new source and classified. Each of this primary classifier has special characteristics and discriminates the spectral space particularly. With using of the benefits of all primary classifiers, it is made sure that the results of the fused local decisions are accurate enough. In decision fusion center, some rules are used to determine the final class of pixels. This method is applied to real remote sensing data. Results show classification performance is improved, and this method may solve the limitation of training samples in the high dimensional data and the Hughes phenomenon may be mitigated.

• 대한안전경영과학회지
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• 제25권1호
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• pp.61-66
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• 2023

The purpose of this study is to compare and analyze the flame retardant performance of Japanese cypress(Chamaecyparis obtusa) plywood, commonly used in indoor decoration, furniture, and tableware, by treating it with three different fire retardants with different primary ingredients. The experiment was conducted in compliance with Article 31, Paragraph 2 of the Enforcement Decree of the Fire Facilities Installation and Management Act and Articles 4 and 7-2 of the Flame Retardant Performance Standards. After flame time, after glow time, char length, and char area were measured. As a result, first, after flame time was measured at 0 seconds regardless of whether the flame retardant treatment was applied. Second, after glow time was relatively long, measuring 22.7 seconds without treatment, which is likely due to the weak fire resistance and high concentration of carbon monoxide generated by the chemical characteristics of the Japanese cypress itself. Third, it was confirmed that the effects of the primary ingredient, phosphorus, in the flame retardant treatment varied depending on the technological development of the manufacturers of the same species of Japanese cypress plywood. In the future, it is expected that the results of this study will provide fundamental data to select flame retardant treatments that show high flame retardant performance according to the botanical characteristics of the wood.

• Nuclear Engineering and Technology
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• 제55권3호
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• pp.827-838
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• 2023

Centrifugal pump is a key part of nuclear power plant systems, and its health status is critical to the safety and reliability of nuclear power plants. Therefore, fault diagnosis is required for centrifugal pump. Traditional fault diagnosis methods have difficulty extracting fault features from nonlinear and non-stationary signals, resulting in low diagnostic accuracy. In this paper, a new fault diagnosis method is proposed based on the improved particle swarm optimization (IPSO) algorithm-based variational modal decomposition (VMD) and relevance vector machine (RVM). Firstly, a simulation test bench for rotor faults is built, in which vibration displacement signals of the rotor are also collected by eddy current sensors. Then, the improved particle swarm algorithm is used to optimize the VMD to achieve adaptive decomposition of vibration displacement signals. Meanwhile, a screening criterion based on the minimum Kullback-Leibler (K-L) divergence value is established to extract the primary intrinsic modal function (IMF) component. Eventually, the factors are obtained from the primary IMF component to form a fault feature vector, and fault patterns are recognized using the RVM model. The results show that the extraction of the fault information and fault diagnosis classification have been improved, and the average accuracy could reach 97.87%.

• 국제학술발표논문집
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• The 9th International Conference on Construction Engineering and Project Management
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• pp.401-407
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• 2022

Central heating, ventilation and air conditioning (HVAC) is one of the largest consumers of energy in the residential sector. This project explores the use of multiple HVAC units and/or Zoning in a single residence to reduce energy loads. The energy consumption data of a detached single-family home using two HVAC units, one primary for the main house and a secondary HVAC for a casita, was collected for the same month for two consecutive years, along with details related to the outdoor temperature and the square footage being air-conditioned by each HVAC. A regression algorithm was trained using the above details to find the relation between the parameters. Next, based on the occupancy and usage patterns, the HVAC was redesigned assuming more area under the secondary HVAC unit. The trained algorithm was then used to make energy usage predictions for the revised primary HVAC area, with the assumption that the secondary HVAC unit was turned off. The results were compared with existing energy usage data. It was determined that there were significant energy savings in the second scenario. It is expected that this study and its findings will help future research projects explore more ideas as alternatives to central HVAC, in improving the economic viability of existing options, and in developing a savings calculation tool that will help consumers make informed decisions on their best alternatives to central HVAC.

• 영어영문학
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• 제56권1호
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• pp.47-64
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• 2010

It is unfair that environmental pragmatism has been regarded as a mouthpiece for industrial expediency and business boosterism. John Dewey's radical pragmatism known as 'Instrumentalism' has provoked ecological fundamentalists' criticism more vehemently than any other pragmatic philosophies. However, most of the presumptive misunderstandings of such critics as Holmes Rolston, J. Baird Calliott, Erich Katz, C. A. Bowers and many others come from their limited or reduced reading of Deweyan pragmatism. The following three aspects of Deweyan pragmatism can work out in opening up a dialogical space with those eco-centrist thinkers mentioned above. First, the concept of Dewey's 'primary experience' can articulate the foundationalist view of nature, which is often found in aboriginal cultures. Second, as Andrew Light points out, ecological essentialism can share its metaphilosophical position with the pragmatist epistemology. While Anthony Weston pursues pluralism, admitting that the foundationalism might be one of the efficient approaches to nature, Eric Katz is also clearly attracted to the metaphilosophical element in Weston's argument that anyone who attempts to claim the 'inherent value' of non-human nature never possibly avoids a pitfall of anthropomorphism. Lastly, in a more comprehensive perspective, Dewey's pragmatism shows a philosophical complexity, what Larry A. Hickman calls 'post-postmodernism.' a dynamic interaction between modernism and postmodernism. Significantly enough, the environmental version of this complexity can procure a meeting ground between foundationalist ecology and the pragmatic view of nature.

• 대한두개안면성형외과학회지
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• 제25권2호
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• pp.90-94
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• 2024

Primary cutaneous mucinous carcinoma (PCMC) is a rare malignancy of the sweat glands that most commonly affects the periorbital area. It is characterized by slow growth over a prolonged period, and its morphology can be easily confused with a benign tumor, such as an epidermal cyst. Consequently, many patients experience recurrence after undergoing multiple resections. However, there are few reports concerning the surgical management of PCMC. We present two cases of PCMC originating in the periorbital area. The first case involved a 76-year-old man with a mass measuring 3.0×1.5 cm that had been increasing in size. The second case was a 61-year-old man with two masses, each measuring 1.0×1.0 cm, that were also growing. Both patients underwent wide excision with a 5-mm safety margin, which was determined based on the widest view of the cross-section of the mass on the magnetic resonance imaging. Subsequently, based on the intraoperative frozen biopsy results, both patients underwent additional excision with a 5-mm safety margin in only one direction. This report shows that, when determining the surgical margin of PCMC in periorbital area, employing imaging modalities and intraoperative frozen biopsies can be helpful for narrowing the surgical margin.

• Journal of Periodontal and Implant Science
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• 제38권4호
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• pp.723-728
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• 2008

Purpose: During guided bone regeneration procedures for the augmentation of deficient alveolar ridge, primary closure of flap is necessary. For primary flap closure, flap is repositioned coronally and the zone of attached keratinized mucosa may decreased. The need for attached keratinized mucosa around dental implants is still controversial, but sufficient peri-implant attached keratinized mucosa would be beneficial for functional and esthetic aspects. This case report presents three cases that demonstrated free gingival graft for increasing the zone of peri-implant attached keratinized mucosa which was decreased after guided bone regeneration. Materials and Methods: In first case, maxillary incisors were extracted and guided bone regeneration was performed simultaneously. Because the membrane was exposed at 3 weeks after operation, the membrane was removed and free gingival graft was performed for primary flap closure. Free gingival graft was performed again at implant placement for the increase of attached keratinized mucosa. In second case, guided bone regeneration was performed on lower right first molar area, and implant was placed with free gingival graft. In third case, lower right molar area showed insufficient attached keratinized mucosa after implant placement with guided bone regeneration. When abutments were connected, free gingival graft with apically positioned flap was performed. Result: In these three cases, the zone of attached keratinized mucosa around dental implants was decreased after guided bone regeneration. And the increase of peri-implant attached keratinized mucosa could be obtained effectively by free gingival graft. Conclusion: Free gingival graft could be a effective treatment method increasing the zone of attached keratinized mucosa which was decreased after guided bone regeneration procedures.

• 가정과삶의질연구
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• 제34권3호
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• pp.27-43
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• 2016

This study aims to better estimate the amount of time spent for child care and to understand the characteristics of time spent for child care among employed and non-employed mothers with children under age 6 by taking concurrent activities into account. To assess time spent for child care, I differentiate child care activities into three types: primary activity without concurrent activities, primary activity with concurrent activities, and secondary activity with concurrent activities. The Major results of this study are as follows: First, employed mothers spent 145 minutes less than non-employed mothers in the total amount of time spent for child care during weekdays and this difference diminished to 62 minutes on weekends. Specifically there were differences in all types of time spent for child care among employed and non-employed mothers during weekdays, while the difference was only significant in the average amount of primary time spent for child care without concurrent activities on weekends. Second, there was no difference in the average ratio of time spent for child care with concurrent activities among employed and non-employed mothers during weekdays. By contrast, the average ratio of time spent for child care with concurrent activities of employed mothers was 5% higher than non-employed mothers on weekends. Lastly, the highest concurrent activity with child care activities was leisure followed by housework. This means that child care, leisure, and housework are somewhat related to each other among mothers.

• 한국초등과학교육학회지:초등과학교육
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• 제21권1호
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• pp.61-70
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• 2002

The purpose of this study was to examine whether or not they have been revised corresponding to the purpose of revision by making a comparative analysis of the content and illustration in the 6th and 7th primary science textbooks. The analysis of content was composed of knowledge, inquiry process and attitude. The analysis of illustrations was composed of the kinds of illustrations and the role of illustrations. The findings of this research were as follows: First, as a result of content analysis of the primary science textbooks in the 6th and the 7th national curriculum, the ratio of inquiry process showed the highest frequency, next knowledge and lastly scientific attitude. And the 7th textbooks are greatly emphasized knowledge and science attitude. Second, as a results of the illustration analysis are as follows: There are conspicuous differences in that the illustration number of the 7th science textbooks Is about twice the illustration number of the 6th science textbooks and next, they place more weights on pictures and comics hard to discovery in the 6th science textbooks. Therefore, they have tried to induce the interests of students and heighten their understanding by supplementing the role of illustration presented as picture-centered and increasing its number presented as picture. In the results, although they have improved the problems of the 6th national curriculum a lot through the innovation including the interest induction of pupils through comics, the development of its content presentation method, the gradual change of subject number and the cultivation of curriculum according to the level of enrichment and supplementing types, the 7th science textbooks have fallen short of 6.3%, not around 30% in terms of the reduction in the 7th national curriculum. Accordingly, the 7th science textbooks also can be pointed out to have the problems of too much amount of studying compared to the time per week like the 6th science textbooks.