• 한국환경복원기술학회지
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• 제17권1호
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• pp.111-122
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• 2014

The provided habitat of many services from natural capital is important. But because most ecosystem services tools qualitatively evaluated biodiversity or habitat quality, this study quantitatively analyzed those aspects using the species distribution model (MaxEnt). This study used location point data of the goat(Naemorhedus caudatus), marten(Martes flavigula), leopard cat(Prionailurus bengalensis), flying squirrel(Pteromys volans aluco) and otter(Lutra lutra) from the 3rd National Ecosystem Survey. Input data utilized DEM, landcover classification maps, Forest-types map and digital topographic maps. This study generated the MaxEnt model, randomly setting 70% of the presences as training data, with the remaining 30% used as test data, and ran five cross-validated replicates for each model. The threshold indicating maximum training sensitivity plus specificity was considered as a more robust approach, so this study used it to conduct the distribution into presence(1)-absence(0) predictions and totalled up a value of 5 times for uncertainty reduction. The test data's ROC curve of endangered mammals was as follows: growing down goat(0.896), otter(0.857), flying squirrel(0.738), marten(0.725), and leopard cat(0.629). This study was divided into two groups based on habitat: the first group consisted of the goat, marten, leopard cat and flying squirrel in the forest; and the second group consisted of the otter in the river. More than 60 percent of endangered mammals' distribution probability were 56.9% in the forest and 12.7% in the river. A future study is needed to conduct other species' distribution modeling exclusive of mammals and to develop a collection method of field survey data.

• 한국산학기술학회논문지
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• 제16권9호
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• pp.5769-5777
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• 2015

프레스 가공에서 포밍이나 굽힘 등의 변형에 따라 판재는 가공경화를 발생하게 되며, 판재 경화와 가스 스프링 반력에 의한 캠 성형 과정에서 캠 및 판재의 변형과 미 성형이 발생하게 된다. 본 연구는 알루미늄 판재 성형 과정에서 판재경화를 고려한 응력, 변형이 주어진 판재 물성치와 캠 성형 압력에 맞게 입력 값으로 처리하였다. 그리고 유한요소 해석툴인 Hyperstudy와 Abaqus 연동으로 캠 형상을 비선형적으로 형상 최적화 해석을 수행 했다. 그 결과 판재의 변형이 제거 되면서 허용되는 최대, 최소 응력 범위와 최소 변형을 갖는 조건하에서 캠 형상을 최적화 하였다. 따라서 해석 결과를 통해 응력-변형 곡선과 응력-두께의 정규 분포도를 얻을 수 있었고, 또한 Iteration 처리로 판재 경화와 가스 스프링 반력을 고려한 다이캠 두께에 맞는 응력과 변형에 대한 최적화 형상을 얻을 수 있었다.

• 융합신호처리학회논문지
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• 제10권4호
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• pp.233-238
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• 2009

본 논문에서는 얼굴을 자동 초점(Auto-focus) 디지털 카메라의 관심영역(ROI : Region Of Interest)으로 이용하는 시스템에서 요구되는 검출 영역의 안정적인 선택을 위한 방법을 제안한다. 이 방법은 디지털 카메라와 모바일 카메라에 포함되는 ISP(Image Signal Processor)에서 실시간으로 처리되는 프로그레시브 입력 영상에서 얼굴 영역을 관심영역으로 간주하고 자동으로 초점을 맞추는 방법이다. 얼굴 영역 검출을 위하여 사용한 학습 알고리즘은 에이다부스트 알고리즘을 이용하였다. 학습에 포함되지 않은 기울어진 얼굴에 대한 검출방법과 검출 결과에 대한 후처리 방법, 관심영역이 흔들리지 않고 일정한 영역을 유지하도록 하기 위한 안정화 대책을 제안한다. 제안된 ROI 영역 안정화 알고리즘에 대한 성능을 평가하기 위하여 움직임이 있는 얼굴에 대하여 기준 궤적과의 차이를 보이고, 각 궤적의 회귀곡선과의 RMS 오차를 안정화 성능평가의 척도로 이용하였다.

• 한국도로학회논문집
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• 제9권4호
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• pp.55-63
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• 2007

노상토의 변형특성은 포장체의 역학적 해석 및 설계에서 매우 중요한 입력물성치다. 본 연구에서는 시편 성형방법에 따른 국내 노상토의 변형특성 평가를 위하여. 다양한 성형기법을 적용하여 만들어진 시편에 대한 공진주시험을 수행하였다. 시편 성형방법에 따라서 최대탄성계수는 영향 받았으나 정규화탄성계수 감소곡선은 영향받지 않았다. 시편 성형기법의 영향은 구속응력이 증가할 수록 감소하였다. 시편 성형방법에 따른 탄성계수의 평균적인 최대편차는 16.8%로 나타났다. 동일한 함수비 및 건조단위중량 조건에서 선회다짐과 충격다짐으로 성형된 시편의 탄성계수 차이는 5.2% 이내로 매우 작았다. 충격다짐의 장점은 선회다짐에 비하여 보다 간편하고 시편성형 장비비용이 저렴하여 실무적용성이 우수함을 고려하여 설계입력물성치 결정을 위한 시편성형기법으로서 충격다짐기법을 제안하였다.

• 한국초지조사료학회지
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• 제10권2호
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• pp.102-109
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• 1990

This experiment was carried out to study the effect of pure mineral nitrogen fertilizing on dry matter yield of grassland and the advisable mineral nitrogen amounts in long duration under practical conditions at the "Federal Institute for Agriculture in the Alps" in Austria. The application rates were 0, 30, 60,90 and 120 kg N/ha/cut, the cutting regimes 3-, 4-, 5- and 6-cuts/year. In order to explain the nitrogen-profitability were determined that 1 kg pure mineral nitrogen have to produce 8 - 16 kg DM/kg N in dependence on cutting regimes and requiring of nitrogen efficiencies. The results were as follows: 1. With only PK-fertilizaing average dry matter yields from 4.0 to 7.6 tons per ha and year were obtained. 2. Within all applied cutting regimes 60 kg min. Nlhalgrowth have proved to be the most efficient application rate witn 13 - 24 kg DM/kg N in dependent of cutting regimes. Comapred with only PK-treatment the DM yields increased by 3.9 - 4.7 t/ ha nad year. 3. By the sigmaformed process of Input-Output curve the highest marginal yield (the "most efficient" Ndressing rate) per ha and year was calculated: 152 kg N at 3-cut regimes, 204 kg N at 4-cut regimes, 220 kg N at 5-cut regimes and 240 kg N/ha/year at 6-cut regimes. 4. With required efficiencies of 16 and 12 kg DM/kg N 240 - 300 kg N per ha and year respectively would have to be applied at 3-cut regimes; with required efficiencies of 12 and 10 kg DM/kg N at 4-cut regimes the appropriate figures ranged from 320 to 420 kg N/ha and year, at 5- and 6-cut regimes and efficiencies of 10 and 8 kg DM/kg N results of 360 - 460 kg N and 380 - 500 kg N respectively were obtained. 5. At the relatively dry location Piber the highest dressing rates were needed in order to obtain the efficiencies from 8 to 16 kg DM/kg N, about 30 - 60 kg N/ha/year more than at the relatively moist location Admont.ist location Admont.

• Smart Structures and Systems
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• 제16권1호
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• pp.163-181
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• 2015

This research investigates the structural health monitoring of nonlinear structures after a major seismic event. It considers the identification of flag-shaped or pinched hysteresis behavior in response to structures as a more general case of a normal hysteresis curve without pinching. The method is based on the overall least squares methods and the log likelihood ratio test. In particular, the structural response is divided into different loading and unloading sub-half cycles. The overall least squares analysis is first implemented to obtain the minimum residual mean square estimates of structural parameters for each sub-half cycle with the number of segments assumed. The log likelihood ratio test is used to assess the likelihood of these nonlinear segments being true representations in the presence of noise and model error. The resulting regression coefficients for identified segmented regression models are finally used to obtain stiffness, yielding deformation and energy dissipation parameters. The performance of the method is illustrated using a single degree of freedom system and a suite of 20 earthquake records. RMS noise of 5%, 10%, 15% and 20% is added to the response data to assess the robustness of the identification routine. The proposed method is computationally efficient and accurate in identifying the damage parameters within 10% average of the known values even with 20% added noise. The method requires no user input and could thus be automated and performed in real-time for each sub-half cycle, with results available effectively immediately after an event as well as during an event, if required.

• Coupled systems mechanics
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• 제4권4호
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• pp.279-295
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• 2015

The article presents a theoretical-experimental approach developed for modeling the coefficient of sliding friction in the dynamic system tool-workpiece in slide diamond burnishing of low-alloy unhardened steels. The experimental setup, implemented on conventional lathe, includes a specially designed device, with a straight cantilever beam as body. The beam is simultaneously loaded by bending (from transverse slide friction force) and compression (from longitudinal burnishing force), which is a reason for geometrical nonlinearity. A method, based on the idea of separation of the variables (time and metric) before establishing the differential equation of motion, has been applied for dynamic modeling of the beam elastic curve. Between the longitudinal (burnishing force) and transverse (slide friction force) forces exists a correlation defined by Coulomb's law of sliding friction. On this basis, an analytical relationship between the beam deflection and the sought friction coefficient has been obtained. In order to measure the deflection of the beam, strain gauges connected in a "full bridge" type of circuit are used. A flexible adhesive is selected, which provides an opportunity for dynamic measurements through the constructed measuring system. The signal is proportional to the beam deflection and is fed to the analog input of USB DAQ board, from where the signal enters in a purposely created virtual instrument which is developed by means of Labview. The basic characteristic of the virtual instrument is the ability to record and visualize in a real time the measured deflection. The signal sampling frequency is chosen in accordance with Nyquist-Shannon sampling theorem. In order to obtain a regression model of the friction coefficient with the participation of the diamond burnishing process parameters, an experimental design with 55 experimental points is synthesized. A regression analysis and analysis of variance have been carried out. The influence of the factors on the friction coefficient is established using sections of the hyper-surface of the friction coefficient model with the hyper-planes.

• 한국자기학회지
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• 제8권6호
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• pp.388-394
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• 1998

자성물질의 자기이방성을 측정하기 위해 개선된 구조의 null-type 토크마그네토미터를 설계, 제작하였다. 제작된 토크마그네토미터의 측정범위는 $0~{\pm}15\;dyne.cm$이며 조절이 가능하다. 이 범위내에서 분해능은 약 0.0005 dyne.cm 정도이며, 1회 측정시 잡음수준은 ~0.01 dyne.cm, 10회 반복측정한 경우 ~0.004 dyne.cm 이하였으며, 반복재현시 나타나는 오차는 0.5% 이하였다. 본 연구에서 제작된 토크마그네토미터는 종전의 null-type 토크마그네토미터와는 달리 영구자석을 내부에, 헬름홀쯔 코일을 외부에 위치시킨 구조의 토크미터를 포함하고 있다. 이로 인하여, 기하학적으로 등방적인 모양으로 토크미터를 설계할 수 있었으며, 헬름헬쯔 코일의 입력전선과 출력전선의 역학적 및 전기적 임피던스에 으히나 토크곡선의 왜곡을 방지할 수 있었고, 샘플막대의 관성모멘트를 줄일 수 있었다. 그 결과 토크에 대하 보다 민감하면서도 반응속도가 빠르며 토크곡선의 왜곡요인이 적은 토크마그네토미터를 제작할 수 있었다.

• Earthquakes and Structures
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• 제13권2호
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• pp.151-164
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• 2017

This article aims to investigate the possible retrofitting of a deficient building with soft story failure mode by connecting it to an adjacent building which is designed based on current code with friction dampers at all floors. Low cost and high performance reliability along with significant energy dissipation pertaining to stable hysteretic loops may be considered in order to choose the proper damper for connecting adjacent buildings. After connecting two neighbouring floors by friction dampers, the sliding forces of dampers at various stories are set in two arrangements: uniform sliding force and then variable sliding force. In order to account for the stochastic nature of the seismic events, incremental dynamic analyses are employed prior and after the installation of the friction dampers at the various floors. Based on these results, fragility curves and mean annual rate of exceedance of serviceability and ultimate limit states are obtained. The results of this study show that the collapse mode of the deficient building can affect the optimum arrangement of sliding forces of friction dampers at Collapse Prevention (CP) performance level. In particular, the Immediate Occupancy (IO) performance level is not tangible to the sliding force arrangement and it depends solely on sliding force value. Generally it can be claimed that this rehabilitation scheme can turn the challenge of pounding two adjacent buildings into the opportunity of dissipating a large amount of the seismic input energy by the friction dampers, thus improving significantly the poor seismic performance of the deficient structure.

• 한국염색가공학회지
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• 제32권4호
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• pp.217-225
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• 2020

In this study, the dyeing characteristics of nylon fabric which is dyed with supercritical fluid were investigated. There were two dyes used in the dyeing experiment: C.I. Disperse Red 167 and C.I. Disperse Violet 93. Dyeing temperature, pressure, and leveling time were fixed at 110℃, 250bar, 60minutes, and the experiment was conducted with dyeing concentration of 0.1, 0.3, 0.5, and 0.85% o.w.f. The analysis of the experimental results was found out through the measurement of washing fastness and color coordinate. In addition, the calibration curve of each dye was drawn up and the amount of remaining dye was checked by measuring the absorbance of the residual dye. As a result of color difference measurement, as the concentration increased, the L⁎ value decreased and the K/S value increased. However, the increase in K/S value compared to the amount of input decreased as the concentration increased. The comparative experiment on the amount of residual dye(C.I. Disperse Red 167) in the pot showed that 99.14% of the amount was dyed at the concentration of 0.1% o.w.f, while it rapidly decreased to 77% at 0.85% o.w.f. C.I. Disperse Violet 93 dye also decreased from 0.5% o.w.f to 93.91%. In the washing fastness experiment of both dyes, the level of washing fastness began to decrease from samples dyed at 0.5% o.w.f. It may be because the simply absorbed dye was produced instead of completely being fixed in the amorphous region of the nylon fiber.