• Title/Summary/Keyword: 율특성

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Development of Applied Indicator according to Locational Type for Secure of Parks and Green Areas in Residential Land Development District (택지개발지역의 입지유형에 따른 공원녹지확보 적용지표 개발)

  • Han, Bong-Ho;Choi, Jin-Woo;Yeum, Jung-Hun;Ahn, Young-Hee
    • Journal of the Korean Institute of Landscape Architecture
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    • v.40 no.1
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    • pp.34-42
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    • 2012
  • This study aims to suggest the secure indicator of parks and green areas according to the properties of the location. There were 31 study areas where negotiation was finalized from 2001 to 2008. The location types were divided by land use type before development and the ratio of mountainous and constructed parks, the ratio of green change and so forth were analyzed according to the those types. As a result, location types were classified into mountainous type, arable land type, urban district type. In terms of locational property, even though the ratio of parks and green areas was the highest at 24.9% in arable land type, the ratio was not much different from the others. Mountainous type depends on the ratio of mountainous park with 10.5%, and arable land type, and urban district type has high ratio of constructed parks. And, the ratio of green change arable land type is degraded by 32.8% and the ratio of mountainous green change is serious in the mountainous type. As a result of the selection of negotiation indicator, arable land type is closely related to the ratio of parks and green areas and the ratio of green change; mountainous type, the ratio of park and green, the ratio of mountainous green change and the ratio of constructed park and green; urban district type, the ratio of green areas.

The Impact of Street Characteristics on the Streetscape Greenness Index in Rural Area - Focused on Yesan-gun - (농촌지역 가로특성이 가로 녹시율에 미치는 영향 - 예산군을 중심으로 -)

  • Lee, Hyuk-Gyun;Cho, Yong-Hyeon;Kim, Tae-Jong
    • Journal of the Korean Institute of Landscape Architecture
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    • v.47 no.6
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    • pp.78-86
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    • 2019
  • The study analyzed the greenness index that residents experience on the streets of rural areas, where characteristics are different from those of urban areas and the effects of these characteristics were investigated. In Yesan-gun, Chungnam, in order to analyze the greenness indices, the streets were categorized into 7 types. Then, two types of streetscape greenness indices were surveyed, analyzed, and compared. One is the street-trees greenness index which takes into account only the trees lining the street and the other is the street greenness index considering total artificial green, natural green, and productive green surfaces. As a result, using the street-tree greenness index the street greenness index of Yesan-gun was analyzed as 15.93% on national highways, 26.14% for local roads, 28.28% for gun-roads, 24.72% for myun-roads, 40.70% for li-roads, 32.78% for nong-roads, and 18.36% for urban planning roads. Using the street greenness index, the street-trees greenness index was analyzed to be 5.02% for national highways, 9.10% for local roads, 8.55% for gun-roads, 4.51% for myun-roads, 6.92% for li-roads, 2.56% for nong-roads, and 9.39% for urban planning roads. To analyze what factors have an impact on the street-trees greenness index and the street greenness index, the study analyzed the effects of street side-land uses, lane types, street-trees, and sidewalks. As a result, both the street greenness index and the street-trees greenness index responded according to the land use adjacent to the street, lane types, and sidewalks. The street greenness index did not change due to the existence of street-trees, but the street-trees greenness index did. Through comparison with other studies, it was found that Yesan-gun needs to improve its streetscape to improve its greenness index rating.

A Study on the Dielectric Properties of SBS/Conductive Filler/Dielectrics Composites for Phantom Model (팬텀 모델 제작을 위한 SBS/도전체/유전체 3상 복합재료의 유전특성 연구)

  • Kim, Yoon-Jin;Choi, Hyung-Do;Cho, Kwang-Yun;Yoo, Don-Sik;Yoon, Ho-Gyu;Suh, Kwang-Seok
    • Polymer(Korea)
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    • v.25 no.1
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    • pp.98-107
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    • 2001
  • Dielectric properties and shape memory characteristics of SBS composites filled with carbon black as conductive filler and (Ba,Ca)$(Sn,Ti)O_3$ or $SrTiO_3$ as dielectrics were investigated for the development of phantom model. SBS/carbon black composite showed an increment of complex dielectric constant with increasing the content of carbon black and the frequency dependence that the dielectric constant decreases with the frequency. The complex dielectric constant and the conductivity of SBS/carbon black/dielectrics composites increased with the increase of dielectrics and the characteristics of the frequency dependence also occurred by the effect of carbon black. Phantom materials with the dielectric properties and the conductivity corresponding to human tissues for the measurement of specific absorption rate(SAR) within the frequency range of current mobile phones(775MHz~2GHz) could be developed by adjusting the composition ratios of carbon black, dielectrics and SBS and by controlling the characteristic of frequency dependence of composite. From thermomechanical cycling test good shape recoverability could be obtained in SBS composite even though the residual strain was increased by the effect of filler.

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Estimation of Dynamic Displacement and Characteristics of A Simple Beam from FBG Sensor Signals (FBG센서 응답을 이용한 단순보의 동적 변위 및 동특성 추정)

  • Choi, Eun Soo;Kang, Dong Hoon;Chung, Won Seok;Kim, Hak Soo
    • Journal of Korean Society of Steel Construction
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    • v.18 no.4
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    • pp.503-514
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    • 2006
  • FBG sensors are capable of measuring the strain of structures easily and more durably than electric resistance gauges. Thus, many researches are dedicated to the application for the response monitoring or non-destructive evaluation of structures using FBG sensors. Additionally, the measured strains at the top and bottom of a cross-section can be transformed into the curvature of the section, which can be used to calculate its vertical displacement. Hence, this study aims to measure the dynamic strain signals of a steel section simply supported beam and to estimate the dynamic displacement from the strain signals, after which the estimated displacement is com pared with the measured displacement. The dynamic characteristics (natural frequency, damping ratio and mode shape) of the beam are predicted from both the estimated and measured displacement signals, and from the strain time history of the FBG sensors. The predicted properties are compared with those of an analytical model of the beam. The estimated displacement. However, the predicted dynamic properties from both the estimated displacements and the measured strains are well-correlated with those from the measured displacement. It is therefore appreciated that the estimation of the dynamic properties of FBG sensor signals is reasonable. Especially, the strain signal of the FBG sensor was amplified at a higher-frequency region in comparison with the displacement estimation with higher-mode properties.

Improvement of the Strength Properties and Impact Resistance of the Cement Composite Materials by the use of Surface Modification of the Aramid Fibers (아라미드섬유의 표면개질에 의한 시멘트 복합재료의 강도특성 및 내충격성능의 향상효과)

  • Nam, Jeong-Soo;Yoo, Jae-Chul;Kim, Gyu-Yong;Kim, Hong-Seop;Jeon, Joong-Kyu
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.19 no.1
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    • pp.100-108
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    • 2015
  • The purpose of this study is to evaluate the effect of improvement on the impact resistance and strength properties of cement composites by surface modification of aramid fiber. For aramid fiber reinforced cement composites, therefore, dispersion capability and the bonding efficiency between the fibers and the cement composite material need to be improved. It is possible by modifying surface properties to hydrophobic, it is considered that oiling agent ratio of 1.2 % and improvement of performance is in need to be investigated. In this study, short aramid fibers were mixed by different fiber length and oiling agent ratio. And improvement of strength properties and impact resistance performance of hybrid cement composites were evaluated under the influence of steel fiber. As a result, strength properties of aramid fiber reinforced cement composites are different by mixing ratio of fiber, oiling agent ratio and length of fiber. In case of cement composites which have same volume fraction and fiber length, tensile strength and flexural strength were improved with increase of the emulsions throughput of the fiber surface. The results of evaluation on the static strength properties had effects on impact resistance performance by high-velocity impact. And it was observed that the scabbing of rear was suppressed with increase of the oiling agent ratio.

Stress-Strain Behavior and Electrical Resistive of Conductive Silver Particle/Silicone Composite Pastes with Surface Modification (표면처리에 따른 도전성 은입자/실리콘 복합 페이스트의 응력-변형율 거동 및 전기비저항 특성)

  • 이건웅;방대석;박민;조동환
    • Composites Research
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    • v.17 no.5
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    • pp.61-67
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    • 2004
  • This paper reports the electrical conductivity and the stress-strain behavior of silver particle-filled silicone composite pastes for electromagnetic interference (EMI) shielding gasket materials. The percolation threshold (critical concentration) of the composite paste obtained by incorporating irregular sphere-shaped silver particles and room temperature vulcanizing (RTV) silicone resin was determined from the electrical conductivity result. At about 28 vol% Beading of untreated silver particles, the percolation phenomenon occurred and at this critical concentration, the volumetric resistivity, the tensile strength, and the elongation of the pastes were investigated. This work also suggests that the stress-strain characteristics of a composite paste filled with metal particles above the percolation threshold may be effectively improved by properly selecting a coupling agent.

A Study on Combustion Characteristics of Paraffin Blended Fuel on Aluminum Particle Size (알루미늄 입자 크기에 따른 파라핀 혼합연료의 연소 특성 연구)

  • Ko, Soohan;Han, Seongjoo;Ryu, Sunghoon;Kim, Jinkon;Moon, Heejang;Kim, Junhyung;Ko, Seungwon
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2017.05a
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    • pp.791-796
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    • 2017
  • In this study, the combustion characteristics of paraffin blended fuel on aluminum particle size were investigated. The combustion experiments were carried out using aluminum particles with an average particle size of 100 nm and $8{\mu}m$ and microcrystalline paraffin wax (Sasol 0907). A series of comparison was conducted on the regression rate, the pressure curve and the characteristic velocity of pure paraffin and paraffin blended fuels with aluminum particles. It was found that the micro-sized particles enhance the regression rate as the oxidizer mass flux increased. However, the nano-sized particles decrease the regression rate as the oxidizer mass flux is increased.

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Fuzzy Quantization and Rate Control for Very Low Bit­rate Video Coder (초저전송율 동영상 부호기를 위한 퍼지 양자화 및 율 제어에 관한 연구)

  • 양근호
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.7 no.8
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    • pp.1684-1690
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    • 2003
  • In this paper, we proposed a fuzzy controller for the evaluation of the quantization Parameters in the H.263 coder to optimize the subjective quality of each coded frame, keeping the transmission rate constant. We adopted the Mamdani method for fuzzification and the centroid method for defuzzification. The energy and entropy are correlated to features of the HVS in spatial domain, while motion vectors are used to estimate the temporal characteristics of the signal. And then, the fuzzy inputs adapted the variance and the entropy in spatial domain, and the motion vector in temporal domain. We induced the fuzzy membership function and decided the fuzzy relevance to be compatible in visual characteristics. And then, we designed FAM banks. The fuzzy technology has been applied to a practical video compression. This results is obtained an effective rate control technique, an optimum bit allocation and a high subjective quality using fuzzy quantization.