• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 춘계학술대회논문집
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• pp.79-82
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• 2005

This study aims to propose fundamental data for development of noise reduction system that is applied to classification for light-weight impact sound. For this reason, eight types of damping materials were constructed in new construction field. Comparison and analysis among the reduction materials were carried out on the acoustical characteristics through test. In the end, the suitability as a damping material was evaluated by the analysis.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2018년도 춘계 학술논문 발표대회
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• pp.249-250
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• 2018

To control the floor noise generated in the apartment building, a method of reinforcing the floor at the floor is applied. However, since existing buildings are difficult to reinforce upper generations, the ceilings of lower generations should be reinforced. The purpose of this study is to analyze the reduction effect by measuring the impact noise after reinforcing the floor soundproofing material on the ceiling of the existing building. In order to ensure the economical efficiency and flame retardancy of the products used as building interior materials, the existing polyurethane foam was impregnated with mineral to prepare test specimens and attached to the concrete slab surface. As a result, it was shown that heavy impact sound can reduce 2dB~5dB and light impact sound can reduce 4~8dB.

• 한국안전학회지
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• 제29권3호
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• pp.14-19
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• 2014

The global demand for reduction in the weight of automobiles has led many countries to focus on the development of hybrid, eco-friendly, and electric cars. Reduction in the weight of materials can both increase fuel efficiency and maximize automobile performance. Therefore, the design of automobile should be inclined towards the safety aspects. but at the same time, it also consider reducing the structural weight of an automobile. In this study, CFRP side members with circular and double hat shaped section was manufactured. The impact collapse tests performed with change of the stacking condition, such as variation of interface number and outerlayer angle. The impact collapse load and absorbed energy were quantitatively analyzed according to the changes in section shapes and stacking condition. This analysis was performed to obtain design data that can be applied in the development of optimum lightweight members for automobiles.

• 한국음향학회:학술대회논문집
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• 한국음향학회 2002년도 하계학술발표대회 논문집 제21권 1호
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• pp.461-468
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• 2002

Prediction method of floor impact noise for light and heavy weight impact is described. Sound pressure level is predicted based on the impedance method. For floating floor system, noise reduction is studied assuming 1-D mass-spring system. It is found that comparisons of predictions and measurements show good agreements. However, certain correction factor is needed to predict noise reduction of floating floor system.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2001년도 추계학술발표대회 논문집
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• pp.179-182
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• 2001

Impacter tester was build of to evaluate the characterization of non-flamable Glass/phenol laminate plates under the low velocity impact. The damage of composite laminates are matrix cracking, delamination, and fiber breakage for impact energy. In this study, this is to find impact properties of Glass/phenol in used in a forehead part of lighting subway. To determine impact damage characteristics which is made in a laminate, use the UT C-scan after- macrography. And then evaluated the reduction of strength in a rate of impact energy with CAI(Compression After Impact) test

• 한국습지학회지
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• 제22권1호
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• pp.1-7
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• 2020

비점오염은 수계에 악영향을 끼치며 그 영향은 점차 커지고 있다. 이러한 비점오염을 관리하기 위해 정부에서는 LID(Low Impact Development) 시설의 연구와 다양한 효율평가를 시행하고 있다. 본 연구에서는 다양한 LID 시설 중 실제 설치된 투수 블록 시설의 강우 유출 억제를 위한 유출 저감율, 저류 강우량 분석 및 유출 지연시간 그리고 최대 유입 및 유출의 저감율을 분석했으며, 그 결과를 각 시설 간 비교했다. 불투수블록, 필터형 투수블록, 틈새형 투수블록 순서대로 분석 결과 저감 효율이 높게 나타났으며, 이를 통해 강우강도-유출지연시간간의 관계를 나타낸 그래프를 제시하였다. 이 그래프를 통해 앞으로 설계 시, 본 시설과 유사한 투수블록 시설의 재현 기간에 따른 시설 용량 선정 등의 설계에 도움을 줄 수 있으리라 생각한다.

• 대한두개안면성형외과학회지
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• 제11권2호
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• pp.77-84
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• 2010

Purpose: The nasal bones are the most common fracture sites of the facial bones, and a careful reduction may still result in secondary deformities, such as saddle nose, deviated nose, hump nose etc, requiring secondary cosmetic rhinoplasty. Therefore, this study examined the clinical characteristics of nasal bone fractures to propose guidelines for patient selection and surgical procedures to achieve more satisfactory results and to prevent secondary deformities with simultaneous augmentation rhinoplasty and bony reduction. Methods: The study was based on 26 out of 149 nasal bone fracture patients who underwent simultaneous augmentation rhinoplasty with bony reduction between May 2008 and April 2009. Retrospective analysis was performed according to the clinical data, surgical techniques and postoperative results. Results: Of the 26 patients, there were 15 males and 11 females. The incidence according to the Stranc's classification revealed that 62% of patients were injured by a frontal impact and 38% by a lateral impact. Frontal impact plane I (50%) was the most frequent type. At the follow up, 18 (81.2%) out of 22 patients were satisfied with their postoperative outcome, and the remaining 4 patients were fair. No one was dissatisfied. However, 5 cases in 3 patients (23%) had some complications; minimal implant deviation in 2 cases, minor irregularity on the nasal dorsum in 2 cases and palpable implant movement under palpation in 1 case. None of these cases required surgical correction. Conclusion: With the proper guidance, simultaneous augmentation rhinoplasty with bony reduction can prevent secondary deformities and satisfy the cosmetic outcomes.

• 한국물환경학회지
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• 제36권2호
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• pp.109-115
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• 2020

Recently, since impervious areas have increased due to urban development, the water cycle system of urban watersheds has been destructed. Hence, researches on LID (Low Impact Development) technique have been conducted to solve such problems environmentally. In order to verify suitability with the scale and arrangement of LID technique, the runoff reduction effect of the LID technique should be analyzed per small watershed unit. In this study, pre-post difference of the runoff by applying the LID was estimated using the rational method and rainwater treatment capacity equation. As a result, the runoff before and after the application of LID were estimated as 22,533.5 ㎥ and 14,992.1 ㎥, respectively. In addition, rainfall-runoff simulations were carried out using SWMM to evaluate the efficiency of the LID technique. The SWMM simulation results showed that the runoff before and after the application of LID were 21,174 ㎥ and 15,664 ㎥, respectively. Based on the results of the two methods, the scale and arrangement of the LID technique were revised in order to maximize the effect of the water cycle improvement. Rainfall-runoff simulations were carried out using the SWMM with the revised LID techniques. As a result, despite 34.8 % reduction of pervious pavement area, the rate of runoff reduction increased by 2.1 %. These results indicate that designing the scale and arrangement of LID technique, while considering the total amount of inflow entering into each LID techniques, is essential to effectively achieve the goals of runoff reduction in urban development.

• 자원리싸이클링
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• 제32권2호
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• pp.43-51
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• 2023

본 연구에서는 자동차엔진의 신품제조시와 재제조시 발생하는 환경영향을 전과정 관점에서 산정하고 이를 기반으로 온실가스 저감효과를 산정하였다. 자동차엔진 원부자재 원료취득 및 제조공정에서 배출되는 온실가스량은 신품제조시 약 3,473 kg, 재제조시 약 872 kg으로 재제조를 통해 저감되는 온실가스량은 약 2,601kg으로 나타나 폐기 단계를 제외한 전과정 측면에서 저감효과가 있는 것으로 분석되었다. LCA 가중화 분석 결과 신품 제조시 환경영향은 1.07E+03 Eco-point, 재제조시 2.67E+02 Eco-point로 나타났으며, 주요 6대 영향 범주 중 지구온난화 점유비율이 99.72%, 99.68%로 높게 나타났다.

• Journal of Information Processing Systems
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• 제14권2호
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• pp.418-434
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• 2018

With the increasing use of the Internet and electronic documents, automatic text categorization becomes imperative. Several machine learning algorithms have been proposed for text categorization. The k-nearest neighbor algorithm (kNN) is known to be one of the best state of the art classifiers when used for text categorization. However, kNN suffers from limitations such as high computation when classifying new instances. Instance selection techniques have emerged as highly competitive methods to improve kNN through data reduction. However previous works have evaluated those approaches only on structured datasets. In addition, their performance has not been examined over the text categorization domain where the dimensionality and size of the dataset is very high. Motivated by these observations, this paper investigates and analyzes the impact of instance selection on kNN-based text categorization in terms of various aspects such as classification accuracy, classification efficiency, and data reduction.